Running coupling and fermion mass in strong coupling QED

Simple toy model is used in order to exhibit the technique of extracting the non-perturbative information about Green's functions in Minkowski space. The effective charge and the dynamical electron mass are calculated in strong coupling 3+1 QED by solving the coupled Dyson-Schwinger equations for electron and photon propagators. The minimal Ball-Chiu vertex was used for simplicity and we impose the Landau gauge fixing on QED action. The solution obtained separately in Euclidean and Minkowski space were compared, the latter one was extracted with the help of spectral technique.Comment: 23 pages, 4 figures, v4: revised and extended version, one introductory section adde

An Improved Simulated Annealing Technique for Enhanced Mobility in Smart Cities

Vehicular traffic congestion is a significant problem that arises in many cities. This is due to the increasing number of vehicles that are driving on city roads of limited capacity. The vehicular congestion significantly impacts travel distance, travel time, fuel consumption and air pollution. Avoidance of traffic congestion and providing drivers with optimal paths are not trivial tasks. The key contribution of this work consists of the developed approach for dynamic calculation of optimal traffic routes. Two attributes (the average travel speed of the traffic and the roads’ length) are utilized by the proposed method to find the optimal paths. The average travel speed values can be obtained from the sensors deployed in smart cities and communicated to vehicles via the Internet of Vehicles and roadside communication units. The performance of the proposed algorithm is compared to three other algorithms: the simulated annealing weighted sum, the simulated annealing technique for order preference by similarity to the ideal solution and the Dijkstra algorithm. The weighted sum and technique for order preference by similarity to the ideal solution methods are used to formulate different attributes in the simulated annealing cost function. According to the Sheffield scenario, simulation results show that the improved simulated annealing technique for order preference by similarity to the ideal solution method improves the traffic performance in the presence of congestion by an overall average of 19.22% in terms of travel time, fuel consumption and CO2 emissions as compared to other algorithms; also, similar performance patterns were achieved for the Birmingham test scenario

The Impacts of the City and County of Denver’s Breed Specific Legislation

In August of 1989, the City and County of Denver, CO, USA enacted legislation that prohibits the presence of all “pit bull” type dogs (PBTD) (defined in Denver as: American Pit Bull Terrier, American Staffordshire Terrier, or Staffordshire Bull Terrier) within the city limits. In the 30 years the “pit bull ban” has been in place, the City and County of Denver and its animal control agency, Denver Animal Protection, have committed substantial resources to removing PBTDs from the community, including patrolling communities and/or responding to complaints made by neighbors, conducting thorough breed evaluations of suspected PBTDs, and kenneling PBTDs found in the city limits. This Social-Environmental-Economic Impact Assessment (SEEIA) examines how the City and County of Denver’s Breed-Specific Legislation (BSL) policy has impacted the economic and social systems of the Denver community. An economic assessment of BSL identified that the City and County of Denver has spent at least $5.8 million on enforcing the legislation, with additional economic analyses estimating that BSL resulted in approximately$107 million in lost direct and indirect economic activity related to lost pet care revenue. BSL in the City and County Denver has resulted in an extended length of stay for PBTDs in the care of animal shelters and also places additional strain on transfer partnerships with shelters in surrounding communities. An estimated $1 million has been spent by shelters in surrounding communities to care for the PBTDs that are transferred as a result of BSL. An assessment of the social impacts of BSL determined that the removal of a single breed of dog is inconsistent with the documented benefits of increasing opportunities for pet-keeping in community. Furthermore, the disproportionate enforcement of BSL in underserved communities and communities of color perpetuates historic trends of discrimination and marginalization in the U.S. and negatively impacts social cohesion of these communities. Despite some of the more negative impacts of the legislation, there appear to be a number of social factors that have sustained Denver’s “pit bull” ban. While in the minority of opinions, 19.4% of Denver residents who participated in an online survey about BSL (n = 252) said that the City and County of Denver’s breed ban positively impacted their perception of Denver and 24.6% of Denver residents said that the breed ban makes them feel safer. This perceived increase in sense of safety, even if only reported for a minority percentage of Denver residents, may continue to serve as the primary reason for policymakers to continue the ban in the present day (Maher, 2009, September 24). The breed ban’s prioritization of human public safety at the expense of the welfare of a specific type of dog, particularly without a substantial impact on the former, represents a diversion from the components that contribute to a Humane Community. In conclusion, we recommend alternatives to BSL that will address the root causes of the issue of dangerous dogs, including: building the City and County of Denver\u27s capacity to support residents in caring for their pets by identifying and expanding pet-support infrastructure such as affordable and accessible veterinary and behavior services, implementing robust non-breed-specific dangerous dog laws, and implementing evidence-based interventions for challenges to social cohesion and interpersonal and interspecies violence

Effect of the National Resident Assessment Instrument on Selected Health Conditions and Problems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111253/1/j.1532-5415.1997.tb02972.x.pd

The Impacts of the City and County of Denver’s Breed Specific Legislation

In August of 1989, the City and County of Denver, CO, USA enacted legislation that prohibits the presence of all “pit bull” type dogs (PBTD) (defined in Denver as: American Pit Bull Terrier, American Staffordshire Terrier, or Staffordshire Bull Terrier) within the city limits. In the 30 years the “pit bull ban” has been in place, the City and County of Denver and its animal control agency, Denver Animal Protection, have committed substantial resources to removing PBTDs from the community, including patrolling communities and/or responding to complaints made by neighbors, conducting thorough breed evaluations of suspected PBTDs, and kenneling PBTDs found in the city limits. This Social-Environmental-Economic Impact Assessment (SEEIA) examines how the City and County of Denver’s Breed-Specific Legislation (BSL) policy has impacted the economic and social systems of the Denver community. An economic assessment of BSL identified that the City and County of Denver has spent at least $5.8 million on enforcing the legislation, with additional economic analyses estimating that BSL resulted in approximately$107 million in lost direct and indirect economic activity related to lost pet care revenue. BSL in the City and County Denver has resulted in an extended length of stay for PBTDs in the care of animal shelters and also places additional strain on transfer partnerships with shelters in surrounding communities. An estimated $1 million has been spent by shelters in surrounding communities to care for the PBTDs that are transferred as a result of BSL. An assessment of the social impacts of BSL determined that the removal of a single breed of dog is inconsistent with the documented benefits of increasing opportunities for pet-keeping in community. Furthermore, the disproportionate enforcement of BSL in underserved communities and communities of color perpetuates historic trends of discrimination and marginalization in the U.S. and negatively impacts social cohesion of these communities. Despite some of the more negative impacts of the legislation, there appear to be a number of social factors that have sustained Denver’s “pit bull” ban. While in the minority of opinions, 19.4% of Denver residents who participated in an online survey about BSL (n = 252) said that the City and County of Denver’s breed ban positively impacted their perception of Denver and 24.6% of Denver residents said that the breed ban makes them feel safer. This perceived increase in sense of safety, even if only reported for a minority percentage of Denver residents, may continue to serve as the primary reason for policymakers to continue the ban in the present day (Maher, 2009, September 24). The breed ban’s prioritization of human public safety at the expense of the welfare of a specific type of dog, particularly without a substantial impact on the former, represents a diversion from the components that contribute to a Humane Community. In conclusion, we recommend alternatives to BSL that will address the root causes of the issue of dangerous dogs, including: building the City and County of Denver\u27s capacity to support residents in caring for their pets by identifying and expanding pet-support infrastructure such as affordable and accessible veterinary and behavior services, implementing robust non-breed-specific dangerous dog laws, and implementing evidence-based interventions for challenges to social cohesion and interpersonal and interspecies violence

Multiplicative renormalizability and quark propagator

The renormalized Dyson-Schwinger equation for the quark propagator is studied, in Landau gauge, in a novel truncation which preserves multiplicative renormalizability. The renormalization constants are formally eliminated from the integral equations, and the running coupling explicitly enters the kernels of the new equations. To construct a truncation which preserves multiplicative renormalizability, and reproduces the correct leading order perturbative behavior, non-trivial cancellations involving the full quark-gluon vertex are assumed in the quark self-energy loop. A model for the running coupling is introduced, with infrared fixed point in agreement with previous Dyson-Schwinger studies of the gauge sector, and with correct logarithmic tail. Dynamical chiral symmetry breaking is investigated, and the generated quark mass is of the order of the extension of the infrared plateau of the coupling, and about three times larger than in the Abelian approximation, which violates multiplicative renormalizability. The generated scale is of the right size for hadronic phenomenology, without requiring an infrared enhancement of the running coupling.Comment: 17 pages; minor corrections, comparison to lattice results added; accepted for publication in Phys. Rev.

Chiral symmetry breaking in dimensionally regularized nonperturbative quenched QED

In this paper we study dynamical chiral symmetry breaking in dimensionally regularized quenched QED within the context of Dyson-Schwinger equations. In D < 4 dimensions the theory has solutions which exhibit chiral symmetry breaking for all values of the coupling. To begin with, we study this phenomenon both numerically and, with some approximations, analytically within the rainbow approximation in the Landau gauge. In particular, we discuss how to extract the critical coupling alpha_c = pi/3 relevant in four dimensions from the D dimensional theory. We further present analytic results for the chirally symmetric solution obtained with the Curtis-Pennington vertex as well as numerical results for solutions exhibiting chiral symmetry breaking. For these we demonstrate that, using dimensional regularization, the extraction of the critical coupling relevant for this vertex is feasible. Initial results for this critical coupling are in agreement with cut-off based work within the currently achievable numerical precision.Comment: 24 pages, including 5 figures; submitted to Phys. Rev.

Association of the Resident Assessment Instrument (RAI) with Changes in Function, Cognition, and Psychosocial Status

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111069/1/j.1532-5415.1997.tb02971.x.pd

Spacelab Life Sciences-1

This report provides an historical overview of the Spacelab Life Sciences-1 (SLS-1) mission along with the resultant biomaintenance data and investigators' findings. Only the nonhuman elements, developed by Ames Research Center (ARC) researchers, are addressed herein. The STS-40 flight of SLS-1, in June 1991, was the first spacelab flown after 'return to orbit', it was also the first spacelab mission specifically designated as a Life Sciences Spacelab. The experiments performed provided baseline data for both hardware and rodents used in succeeding missions

A Series of Manganese(III) Salen Complexes as a Result of Team-Based Inquiry in a Transnational Education Programme.

The development of a team-based approach to research-led transnational practical chemistry teaching is described in which a team of five Chinese students on an articulated transnational degree programme, supported by a team of academic and technical staff, carried out a study examining the structural chemistry of a series of manganese(III) salen complexes. A series of four crystallographically characterized manganese(III) salen complexes with ancillary carboxylate ligands are reported here. The carboxylate coordination modes range from the bridging syn-anti μ2 -κO : κO' mode observed in the predominant cyclohexanoate and isobutyrate species, to a capping terminal monodentate mode for the adamantanoate species, and an unusual mixture of bridging and terminal coordination modes observed in a second minor phase of the cyclohexanoate species. The variation on extended structures based on the weakly interacting aliphatic backbones may provide a useful basis for further structural studies