1,797 research outputs found
Using Regression Discontinuity Design to Identify the Effect of Zoning
We test the effect of minimum lot zoning on rural-to-urban land use conversion using Regression Discontinuity Design (RDD), a technique that exploits natural discontinuities in the data to identify causal effects. Observations are drawn from either size of a discontinuous minimum lot size zoning boundary. Using these selected sub-samples, a binary discrete choice model of residential land use change is estimated using parcel-level data and other spatially explicit data from an exurban county that lies on the fringes of Cleveland, Ohio. Results show that controlling for unobserved correlation in the data clearly identifies a negative and significant effect of larger minimum lot size zoning on the probability of conversion to a residential use.Land Economics/Use,
Fatigue Behavior of Ti-6Al-4V ELI including Mean Stress Effects
This study investigates the cyclic deformation, fatigue behavior, and failure mechanisms for Ti-6Al-4V ELI (extra low interstitial) with and without mean strain/stress. Mean stress effects on fatigue behavior were studied using four strain ratios. Fatigue data generated was used to assess mean stress fatigue life prediction approaches, including stress-based methods such as Goodman, Gerber, Morrow, Walker and Kwofie; as well as strain-based models, such as Morrow, Smith-Watson-Topper, Walker, Kwofie, Ince-Glinka and a modified version of the Smith-Watson-Topper. The stress-based models did not yield reasonable results and data scatter was observed. The strain-based models offered better results, specifically the Morrow approach which provided more accurate fatigue life predictions. Fractography analysis determined that the influence of material defects on fatigue life had no major differences across all the strain ratios considered. Overall observations indicate that inclusions near the surface had great influence on the fatigue behavior
Do Voluntary Pollution Reduction Programs (VPRs) Spur Innovation in Environmental Technology
In the context of the EPA's 33/50 program, we study whether a VPR can prompt firms to develop new environmental technologies that yield future emission reduction benefits. Because pollutant reductions generally require costly reformulations of products and/or production processes, environmental over-compliance induced by a VPR may potentially spur environmental innovation that can reduce these costs. Conversely, a VPR may induce a participating firm to divert resources from environmental research to environmental monitoring and compliance activities that yield short-term benefits in reduced emissions. We find evidence that higher rates of 33/50 program participation are associated with significant reductions in the number of successful environmental patent applications four to six years after the program ended; these results suggest a negative relationship between the 33/50 program and longer-run environmental innovation.Research and Development/Tech Change/Emerging Technologies,
Land Use Change: A Spatial Multinomial Choice Analysis
Urban decentralization and dispersion trends have led to increased conversion of rural lands in many urban peripheries and exurban regions of the U.S. The growth of the exurban areas has outpaced growth in urban and suburban areas, resulting in growth pressures at the urban-rural fringe. A thorough analysis of land use change patterns and the ability to predict these changes are necessary for the effective design of regional environmental, growth, and development policies. We estimate a multinomial discrete choice model with spatial dependence using parcel-level data from Medina County, Ohio. Accounting for spatial dependence should result in improved statistical inference about land use changes. Our spatial model extends the binary choice âlinearized logitâ model of Klier and McMillen (2008) to a multinomial setting. A small Monte Carlo simulation indicates that this estimator performs reasonably well. Preliminary results suggest that the location of new urban development is guided by a preference over lower density areas, yet in proximity to current urban development. In addition, we find significant evidence of spatial dependence in land use decisions.Land Use Change, Multinomial Logit, Spatial Dependence, Community/Rural/Urban Development, Land Economics/Use, Research Methods/ Statistical Methods, R14, C21, C25,
A Representation of the Virasoro Algebra via Wigner-Heisenberg Algebraic Technique to Bosonic Systems
Using the Wigner-Heisenberg algebra for bosonic systems in connection with
oscillators we find a new representation for the Virasoro algebra.Comment: Revised version. Revtex, 7 pages, no figures. This work was presented
in the XXII Brazilian National Meeting on Particles and Fields
(October/2001), to appear in Braz. J. of Phys., 33, 1 (2003
Mesenchymal stem cells for the treatment of systemic lupus erythematosus: is the cure for connective tissue diseases within connective tissue?
Mesenchymal stem cells (MSCs) are now known to display not only adult stem cell multipotency but also robust anti-inflammatory and regenerative properties. After widespread in vitro and in vivo preclinical testing in several autoimmune disease models, allogenic MSCs have been successfully applied in patients with severe treatment-refractory systemic lupus erythematosus. The impressive results of these uncontrolled phase I and II trials - mostly in patients with non-responding renal disease - point to the need to perform controlled multicentric trials. In addition, they suggest that there is much to be learned from the basic and clinical science of MSCs in order to reap the full potential of these multifaceted progenitor cells in the treatment of autoimmune diseases
Big brother is watching - using digital disease surveillance tools for near real-time forecasting
Abstract for the International Journal of Infectious Diseases 79 (S1) (2019).https://www.ijidonline.com/article/S1201-9712(18)34659-9/abstractPublished versio
Study of Apollo water impact. Volume 11 - User's manual for unsymmetric shell of revolution analysis Final report
Users manual on static and dynamic computer programs on linear elastic thin shell theory - Apollo command module water impac
A shared database of underground utility lines for 3D mapping and GIS applications
For the purpose of facility management it is very important to have detailed and up-to-date databases of underground utility lines,
but such data are not always available with adequate accuracy. Hence, the need of collecting and organizing suitable information on
underground services is a fundamental issue when dealing with urban data. Besides, by analyzing the process of designing and laying
new underground infrastructures it is possible to implement an efficient and cost-effective approach to integrate and update existing
maps by exploiting the surveying required for the installation of new facilities. It is also important to underline that collecting all the
data in a unique integrated database (and GIS) gives the possibility to share (at least at a local level) the cartographic and thematic
information for an optimal management of underground networks. In this paper, a database (DB) model for archiving the
underground lines data is presented. The structure of the DB has been designed by following the standard methodology for the
modelling of a relational DB, going through successive phases and originating the external, conceptual and logical model. Finally,
preliminary tests have been carried on for parts of the DB to verify quality parameters
Glueball Regge trajectories from gauge/string duality and the Pomeron
The spectrum of light baryons and mesons has been reproduced recently by
Brodsky and Teramond from a holographic dual to QCD inspired in the AdS/CFT
correspondence. They associate fluctuations about the AdS geometry with four
dimensional angular momenta of the dual QCD states. We use a similar approach
to estimate masses of glueball states with different spins and their
excitations. We consider Dirichlet and Neumann boundary conditions and find
approximate linear Regge trajectories for these glueballs. In particular the
Neumann case is consistent with the Pomeron trajectory.Comment: In this revised version we made some additional remarks on the text.
We also included 2 more references. The glueball spectrum and Regge
trajectories are unchanged. 10 pages, 2 eps figure
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