20,819 research outputs found
A new role for science - II
We are entering a period of change
in the very styles of science
A new role for science - I
Science and technology are in desperate need of change,
just because they have been extraordinarily successful
Tensor-Scalar Torsion
A theory of gravity with torsion is examined in which the torsion tensor is
constructed from the exterior derivative of an antisymmetric rank two potential
plus the dual of the gradient of a scalar field. Field equations for the theory
are derived by demanding that the action be stationary under variations with
respect to the metric, the antisymmetric potential, and the scalar field. A
material action is introduced and the equations of motion are derived. The
correct conservation law for rotational angular momentum plus spin is observed
to hold in this theory.Comment: 10 pages, LaTeX, Mod. Phys. Lett. A accepte
Player agency in interactive narrative: audience, actor & author
The question motivating this review paper is, how can
computer-based interactive narrative be used as a constructivist learn-
ing activity? The paper proposes that player agency can be used to
link interactive narrative to learner agency in constructivist theory,
and to classify approaches to interactive narrative. The traditional
question driving research in interactive narrative is, ‘how can an in-
teractive narrative deal with a high degree of player agency, while
maintaining a coherent and well-formed narrative?’ This question
derives from an Aristotelian approach to interactive narrative that,
as the question shows, is inherently antagonistic to player agency.
Within this approach, player agency must be restricted and manip-
ulated to maintain the narrative. Two alternative approaches based
on Brecht’s Epic Theatre and Boal’s Theatre of the Oppressed are
reviewed. If a Boalian approach to interactive narrative is taken the
conflict between narrative and player agency dissolves. The question
that emerges from this approach is quite different from the traditional
question above, and presents a more useful approach to applying in-
teractive narrative as a constructivist learning activity
Local Decentralization and Economic Growth: Evidence from U.S. Metropolitan and Non-Metropolitan Regions
This paper extends the recent empirical literature on the relationship between local decentralization and growth using data from both metropolitan and non-metropolitan regions in the U.S. The analysis utilizes both metropolitan and non-metropolitan regions, and thus avoids the possible selection bias present in previous research. The results for non-metropolitan regions indicate a relatively weak or negative relationship between the local decentralization measures and local economic growth compared to a positive relationship suggested by a recent study on metropolitan regions. Results for the non-metro regions also suggest that there are different impacts across population and income than we observe for metropolitan regions.Decentralization, metropolitan, non-metropolitan, economic growth
The Impact of Local Decentralization on Economic Growth: Evidence from U.S. Counties
We analyze the impact of fiscal decentralization on U.S. county population, employment, and real income growth. Our findings suggest that government organization matters for local economic growth, but that the impacts vary by government unit and by economic indicator. We find that single-purpose governments per square mile have a positive impact on metropolitan population and employment growth, but no significant impact on nonmetropolitan counties. In contrast, the fragmentation of general-purpose governments per capita has a negative impact on employment and population growth in nonmetropolitan counties. Our results suggest that local government decentralization matters differently for metropolitan and nonmetropolitan counties.fiscal decentralization, metropolitan, nonmetropolitan, population, employment, income, spatial econometrics
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Concentrations and potential health risks of metals in lip products.
BackgroundMetal content in lip products has been an issue of concern.ObjectivesWe measured lead and eight other metals in a convenience sample of 32 lip products used by young Asian women in Oakland, California, and assessed potential health risks related to estimated intakes of these metals.MethodsWe analyzed lip products by inductively coupled plasma optical emission spectrometry and used previous estimates of lip product usage rates to determine daily oral intakes. We derived acceptable daily intakes (ADIs) based on information used to determine public health goals for exposure, and compared ADIs with estimated intakes to assess potential risks.ResultsMost of the tested lip products contained high concentrations of titanium and aluminum. All examined products had detectable manganese. Lead was detected in 24 products (75%), with an average concentration of 0.36 ± 0.39 ppm, including one sample with 1.32 ppm. When used at the estimated average daily rate, estimated intakes were > 20% of ADIs derived for aluminum, cadmium, chromium, and manganese. In addition, average daily use of 10 products tested would result in chromium intake exceeding our estimated ADI for chromium. For high rates of product use (above the 95th percentile), the percentages of samples with estimated metal intakes exceeding ADIs were 3% for aluminum, 68% for chromium, and 22% for manganese. Estimated intakes of lead were < 20% of ADIs for average and high use.ConclusionsCosmetics safety should be assessed not only by the presence of hazardous contents, but also by comparing estimated exposures with health-based standards. In addition to lead, metals such as aluminum, cadmium, chromium, and manganese require further investigation
Electromagnetic radiation from ingested sources in the human intestine between 150 MHz and 1.2 GHz
The conventional method of diagnosing disorders of the human gastro-intestinal (GI) tract is by sensors embedded in cannulae that are inserted through the anus, mouth, or nose. However, these cannulae cause significant patient discomfort and cannot be used in the small intestine. As a result, there is considerable ongoing work in developing wireless sensors that can be used in the small intestine. The radiation characteristics of sources in the GI tract cannot be readily calculated due to the complexity of the human body and its composite tissues, each with different electrical characteristics. In addition, the compact antennas used are electrically small, making them inefficient radiators. This paper presents radiation characteristics for sources in the GI tract that should allow for the optimum design of more efficient telemetry systems. The characteristics are determined using the finite-difference time-domain method with a realistic antenna model on an established fully segmented human body model. Radiation intensity outside the body was found to have a Gaussian-form relationship with frequency. Maximum radiation occurs between 450 and 900 MHz. The gut region was found generally to inhibit vertically polarized electric fields more than horizontally polarized fields
Electromagnetic radiation from ingested sources in the human intestine
There is currently considerable work on the development of wireless sensors that can be used in the small intestine. The radiation characteristics of sources in the gastro-intestinal (GI) tract cannot be readily calculated due to the complexity of the human body and its composite tissues, each with different electrical characteristics. This paper presents radiation characteristics for sources in the GI tract that should allow for the optimum design of more efficient telemetry systems. The characteristics are determined using the finite difference time domain method with a realistic antenna model on an established fully segmented human body model. Maximum radiation was found to occur between 450 and 900 MHz and the gut region was found generally to inhibit vertically polarized electric fields more than horizontally polarized fields
PRICE ENHANCEMENT, RETURNS VARIABILITY, AND SUPPLY RESPONSE IN THE U.S. DAIRY SECTOR
Dairy producers operating in the U.S. have been protected against market price variability by the federal price support program for over 35 years. During the late 1970s tax outlays to operate this program grew at a rapid rate. While many authors have addressed the economic implications of the existing dairy price support program, few have explicitly considered the relationship between risk aversion, capital investment, milk production, and support price policy in this process. This paper considers the role of uncertainty and risk-averse behavior and suggests that these elements are crucial to an economic analysis of the current program and future dairy policy issues.Livestock Production/Industries,
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