53,325 research outputs found

    High quality indoor environments for sustainable office buildings

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    The quality of office indoor environments is considered to consist of those factors that impact occupants according to their health and well-being and (by consequence) their productivity. Indoor Environment Quality (IEQ) can be characterized by four indicators: • Indoor air quality indicators • Thermal comfort indicators • Lighting indicators • Noise indicators. Within each indicator, there are specific metrics that can be utilized in determining an acceptable quality of an indoor environment based on existing knowledge and best practice. Examples of these metrics are: indoor air levels of pollutants or odorants; operative temperature and its control; radiant asymmetry; task lighting; glare; ambient noise. The way in which these metrics impact occupants is not fully understood, especially when multiple metrics may interact in their impacts. While the potential cost of lost productivity from poor IEQ has been estimated to exceed building operation costs, the level of impact and the relative significance of the above four indicators are largely unknown. However, they are key factors in the sustainable operation or refurbishment of office buildings. This paper presents a methodology for assessing indoor environment quality (IEQ) in office buildings, and indicators with related metrics for high performance and occupant comfort. These are intended for integration into the specification of sustainable office buildings as key factors to ensure a high degree of occupant habitability, without this being impaired by other sustainability factors. The assessment methodology was applied in a case study on IEQ in Australia’s first ‘six star’ sustainable office building, Council House 2 (CH2), located in the centre of Melbourne. The CH2 building was designed and built with specific focus on sustainability and the provision of a high quality indoor environment for occupants. Actual IEQ performance was assessed in this study by field assessment after construction and occupancy. For comparison, the methodology was applied to a 30 year old conventional building adjacent to CH2 which housed the same or similar occupants and activities. The impact of IEQ on occupant productivity will be reported in a separate future pape

    Optimal focal-plane restoration

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    Image restoration can be implemented efficiently by calculating the convolution of the digital image and a small kernel during image acquisition. Processing the image in the focal-plane in this way requires less computation than traditional Fourier-transform-based techniques such as the Wiener filter and constrained least-squares filter. Here, the values of the convolution kernel that yield the restoration with minimum expected mean-square error are determined using a frequency analysis of the end-to-end imaging system. This development accounts for constraints on the size and shape of the spatial kernel and all the components of the imaging system. Simulation results indicate the technique is effective and efficient

    The Estimation of Consumer Surplus Benefits from a City Owned Multipurpose Coliseum Complex

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    Coliseums can create consumer surplus benefits by providing types of entertainment to local residents that would otherwise not be available to them. This paper estimates consumer surplus for a major City owned entertainment/convention facility, the Greensboro Coliseum Complex (GCC). A novel aspect of this paper is that it estimates the distribution of consumer surplus across households of different income levels as well as aggregate consumer surplus. It is estimated that aggregate consumer surplus from the GCC in 1999 exceeded the public subsidy for this complex, but a disproportionate amount of the consumer surplus benefits go to higher income households.

    Morphometric Analysis of Dinosaur Tracks from Southwest Arkansas

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    Dinosaur trackways were discovered in Cretaceous De Queen Limestone strata in Howard County, Arkansas, in June 2011. Multiple trackways with variably sized tridactyl tracks were exposed in a commercial quarry, suggesting multiple theropod species or adult and juvenile tracks of a single species. Results of morphometric analyses of 32 plaster casts from selected trackways are reported in an effort to identify the specific track-making dinosaurs and differentiate large and small tracks. Track measurements included length and width of each track, the lengths and widths of each digit impression, and the angular spread (divarication) between digit impressions. Twenty-nine plaster casts were of tridactyl theropod tracks whereas three casts were of poorly preserved tracks of a presumed but unknown tetradactyl (and possibly tetrapod) organism. Plaster casts of tridactyl theropod tracks ranged from 0.36 to 0.61 m long and 0.22 to 0.54 m wide. The longest digit impression on each track was the second, or middle, digit (range = 0.15 – 0.35 m long) with total digit divarication ranging from 31 - 57 degrees. The Arkansas track measurements were compared to tracks (Eubrontes glenrosensis Shuler 1935) preserved in the correlative Glen Rose Formation, Texas and attributed to the large Early Cretaceous carnosaur, Acrocanthosaurus atokensis. The E. glenrosensis track measurements from Texas plotted within the Arkansas data range, suggesting affinity of the Arkansas tracks to E. glenrosensis. Relatively poor preservation of tetradactyl tracks precluded morphometric analysis, but visual comparison to known Cretaceous crocodilian tracks is suggestive of affinity to such organisms

    The Case against a Tennessee Income Tax

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    On November 2 the Tennessee legislature will convene a special session to debate reform of the state tax system. The center of the controversy is whether Tennessee should adopt a personal income tax, as proposed by Gov. Don Sundquist, to close an estimated $400 million budget shortfall. This study finds that a personal income tax in Tennessee would likely have two negative economic effects. First, an income tax would almost certainly reduce economic growth and job creation in the state. The absence of an income tax in Tennessee gives Tennessee a large competitive advantage over other states with which it competes for jobs and businesses. We find, for example, that Kentucky, a state very similar to Tennessee except that it has an income tax, has had considerably weaker economic performance since 1980. Between 1980 and 1998 the per capita economic growth rate of Tennessee was 47 percent compared to 36 percent in Kentucky. The second negative effect of a state income tax would be to trigger much faster growth in state expenditures. That has been the almost universal pattern in other states after they enacted a state income tax. Yet the premise of pro-income tax forces in Tennessee that the state's revenues have been growing too slowly is contradicted by the evidence. In the 1990s, even without an income tax, Tennessee's per capita tax receipts have grown 12th fastest among the 50 states. Tennessee's tax revenues have climbed at twice the rate of inflation plus population growth. The legislature should be cutting taxes, not introducing new ones

    Temporal Dynamics of Decision-Making during Motion Perception in the Visual Cortex

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    How does the brain make decisions? Speed and accuracy of perceptual decisions covary with certainty in the input, and correlate with the rate of evidence accumulation in parietal and frontal cortical "decision neurons." A biophysically realistic model of interactions within and between Retina/LGN and cortical areas V1, MT, MST, and LIP, gated by basal ganglia, simulates dynamic properties of decision-making in response to ambiguous visual motion stimuli used by Newsome, Shadlen, and colleagues in their neurophysiological experiments. The model clarifies how brain circuits that solve the aperture problem interact with a recurrent competitive network with self-normalizing choice properties to carry out probablistic decisions in real time. Some scientists claim that perception and decision-making can be described using Bayesian inference or related general statistical ideas, that estimate the optimal interpretation of the stimulus given priors and likelihoods. However, such concepts do not propose the neocortical mechanisms that enable perception, and make decisions. The present model explains behavioral and neurophysiological decision-making data without an appeal to Bayesian concepts and, unlike other existing models of these data, generates perceptual representations and choice dynamics in response to the experimental visual stimuli. Quantitative model simulations include the time course of LIP neuronal dynamics, as well as behavioral accuracy and reaction time properties, during both correct and error trials at different levels of input ambiguity in both fixed duration and reaction time tasks. Model MT/MST interactions compute the global direction of random dot motion stimuli, while model LIP computes the stochastic perceptual decision that leads to a saccadic eye movement.National Science Foundation (SBE-0354378, IIS-02-05271); Office of Naval Research (N00014-01-1-0624); National Institutes of Health (R01-DC-02852

    The Basic Liberties: An Essay on Analytical Specification

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    We characterize, more precisely than before, what Rawls calls the “analytical” method of drawing up a list of basic liberties. This method employs one or more general conditions that, under any just social order whatever, putative entitlements must meet for them to be among the basic liberties encompassed, within some just social order, by Rawls’s first principle of justice (i.e., the liberty principle). We argue that the general conditions that feature in Rawls’s own account of the analytical method, which employ the notion of necessity, are too stringent. They ultimately fail to deliver as basic certain particular liberties that should be encompassed within any fully adequate scheme of liberties. To address this under-generation problem, we provide an amended general condition. This replaces Rawls’s necessity condition with a probabilistic condition and it appeals to the standard liberal prohibition on arbitrary coercion by the state. We defend our new approach both as apt to feature in applications of the analytical method and as adequately grounded in justice as fairness as Rawls articulates the theory’s fundamental ideas

    Renewable and Nonrenewable Resource Theory Applied to Coastal Agriculture, Forest, Wetland, and Fishery Linkages

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    This paper addresses tradeoffs in wetland development using a framework that integrates economic theory of renewable and nonrenewable resources. The theory treats wetland development as use of a nonrenewable resource, while wetland preservation protects critical fishery habitat. The framework recognizes that wetland quality may vary for either development or fisheries. An illustrative application assesses tradeoffs in converting pocosin wetlands to agriculture rather than maintaining wetlands to protect salinity in estuarine nursery areas. Results reveal the marginal value of salinity protection may be substantial, while location may affect a wetland's value to an estuarine shrimp fishery. Comparisons between agricultural and forestry landuses show that ecological links may cause wetland values to depend upon the land-use chosen for the developed state. Future assessments of other development may reveal additional impacts through impacts on salinity.nonrenewable, renewable, fishery, wetland value, pocosin, Pamlico Sound, Community/Rural/Urban Development, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,
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