Housing

Entry for the Concise Encyclopedia of Economics on Housing covering housing markets and zoning regulations.

Non-radiative decay and stability of NN-heterocyclic carbene iridium(III) complexes

Devices based on deep-blue emitting iridium (III) complexes with N-heterocyclic carbene (NHC) ligands have recently been shown to give excellent performance as phosphorescent organic light-emitting diodes (PHOLEDs). To facilitate the design of even better deep-blue phosphorescent emitters we carried out density functional theory (DFT) calculations of the lowest triplet ($T_1$) potential-energy surfaces (PES) upon lengthening the iridium-ligand (Ir-C) bonds. Relativistic time dependent-DFT (TDDFT) calculations demonstrate that this changes the nature of $T_1$ from a highly-emissive metal-to-ligand charge transfer ($^3$MLCT) state to a metal centered ($^3$MC) state where the radiative decay rate is orders of magnitude slower than that of the $^3$MLCT state. We identify the elongation of an Ir-C bond on the NHC group as the pathway with lowest energy barrier between the $^3$MLCT and $^3$MC states for all complexes studied and show that the barrier height is correlated with the experimentally measured non-radiative decay rate. This suggests that the thermal population of $^3$MC states is the dominant non-radiative decay mechanism at room temperature. We show that the $^3$MLCT $\rightarrow$ $^3$MC transition is reversible, in marked contrast to other deep blue phosphors containing coordinating nitrogen atoms, where the population of $^3$MC states breaks Ir-N bonds. This suggests that, as well as improved efficiency, blue PHOLEDs containing phosphors where the metal is only coordinated by carbon atoms will have improved device lifetimes.Comment: 15 pages, 4 figures, 3 table

Public choice and the economic analysis of anarchy: a survey

Public choice economists began studying the economics of anarchy in the 1970s. Since then, the amount of research on anarchy has burgeoned. This article surveys the important public choice contributions to the economics of anarchy. Following the lead of the early public choice economists, many current economists are researching and analyzing how individuals interact without government. From their non-ublic-interested explanations of the creation of government law enforcement to their historical studies of attempts to internalize externalities under anarchy, public choice scholars are arriving at a more realistic perspective on government and how people interact when government law enforcement is lacking. Although the economics of politics often receives more attention, the economics of anarchy is an important area of research in public choice.anarchism; lawlessness; order; internalization of externalities; self-governance

Corruption and the Institutional Environment for Growth

Several cross-country studies have found that corruption is detrimental to economic growth, but the findings are not universally robust. We utilize the economic freedom index to examine if corruption can facilitate growth by allowing entrepreneurs to avoid inefficient policies and regulations when economic freedom is limited. Using regression analysis, we find that corruption is growth enhancing when economic freedom is most limited but the beneficial impact of corruption decreases as economic freedom increases. Not all areas of economic freedom affect the corruption-growth relationship equally. In particular, we find that when we analyze individual areas of economic freedom the beneficial effect of corruption disappears most quickly when the size of government and the extent of regulation decrease.Corruption; Economic Freedom; Growth

Public Choice and the Economic Analysis of Anarchy: A Survey

Public choice economists began studying the economics of anarchy in the 1970s. Since then, the amount of research on anarchy has burgeoned. This article surveys the important public choice contributions to the economics of anarchy. Following the lead of the early public choice economists, many current economists are researching and analyzing how individuals interact without government. From their non-public-interested explanations of the creation of government law enforcement to their historical studies of attempts to internalize externalities under anarchy, public choice scholars are arriving at a more realistic perspective on government and how people interact when government law enforcement is lacking. Although the economics of politics often receives more attention, the economics of anarchy is an important area of research in public choice.Anarchism; Lawlessness; Order; Internalization of Externalities; Self-Governance

Identity Crisis: The Misclassification of California Uber Drivers

The Uber ridesharing service is synonymous with the rise of mobile application-based services. This business model has spurred a number of novel legal questions, particularly surrounding the proper identification of Uber drivers. Are they employees, guaranteed the ample protections and workers\u27 rights under California law? Or independent contractors, less subject to employer control, but without the same protections the State provides to employees? With the proliferation of these types of services, answering this question is of critical importance, both to current Uber drivers as well as the countless others who will enter this rapidly-developing field in the coming years. This Article provides an answer to that question by applying longstanding California employment law to the Uber model with the aim of properly and accurately characterizing its drivers as legally-recognized employees

\u3cem\u3eNEOCHETINA\u3c/em\u3e SPECIES AND ARTHROPOD COMMUNITIES IN WATER-HYACINTH RAFTS IN SOUTH CAROLINA

Arthropod communities inhabiting feral water-hyacinth rafts were surveyed monthly in South Carolina\u27s Coastal Plain from March 2005 through February 2006. Special attention was given to the chevroned waterhyacinth weevil [Neochetina bruchi (Hustache)], the mottled waterhyacinth weevil [N. eichhorniae (Warner)] (both Coleoptera: Curculionidae), and the waterhyacinth moth [Niphograpta albiguttalis (Warren)] (Lepidoptera: Crambidae), which were imported into North America to control water-hyacinth. Communities of arthropods are compared among sites, flow regimes (lentic, lotic, and tidal), and months of the year. The arthropod communities in waterhyacinth rafts in South Carolina are more diverse than previously reported. Rafts in each of five freshwater systems contained numerous species that were unique to each ecosystem. Water-hyacinth rafts in lentic and lotic systems produced similar arthropod abundances and diversities and contained arthropod assemblages with similar feeding strategies. Rafts that were repeatedly stranded on river banks in tidal waterways contained fewer species than lentic and lotic sites. Tidally stranded plants contained different arthropod assemblages with reduced frequencies of collectors-gatherers, collectors-filterers, and shredders-detritivores and increased frequencies of predators and shredders-herbivores. Arthropod species richness and abundance remained relatively constant throughout the year at each site, with minor fluctuations that coincided with the emergences of Odonata and chironomid Diptera in late spring and early summer. Seven species of aquatic insects are reported as new records for South Carolina. Though none of the three imported biological control agents have ever been released in South Carolina, 3 all were collected. Niphograpta albiguttalis was not collected at the regular study sites but was recorded during initial surveys in 2004. Both of the Neochetina weevil species were collected at all seven study sites during this study. Weevil abundances varied among sites and between species. Neochetina eichhorniae was significantly more abundant than N. bruchi at two sites, and the two species were about equally abundant at the five remaining sites. Weevil abundances were similar at lentic and lotic sites but were slightly reduced in tidally stranded rafts. An inverse, temporal relationship occurred between abundances of adult weevils and their larvae. In addition, descriptions and illustrations of the larvae of the water-hyacinth weevils are provided for discriminating between the two species

Modelling spatial strategies for the durable deployment of crop disease resistance

Maximising the durability of crop disease resistance genes in the face of pathogen evolution is a major challenge in modern agricultural epidemiology. Spatial diversification in the deployment of resistance genes, where susceptible and resistant fields are more closely intermixed, is predicted to drive lower epidemic intensities over evolutionary timescales. This is due to an increase in the strength of dilution effects, caused by pathogen inoculum challenging host tissue to which it is not well-specialised. The factors that interact with and determine the magnitude of this spatial effect are not currently well understood however, leading to uncertainty over the pathosystems where such a strategy is most likely to be cost-effective. We initially use a spatially explicit model, incorporating seasonality and localised reservoirs of inoculum, to explore disease dynamics within landscapes containing a mixture of fields planted with either susceptible or resistant cultivars. When the spatial diversification of these fields is maximised, with lower aggregation of similar fields, the overall intensity of the landscape scale epidemic is reduced. The strength of this spatial effect however depends strongly on the pathogen dispersal characteristics, any fitness cost(s) of the resistance breaking trait, the efficacy of host resistance, and the length of the timeframe of interest. The conclusions drawn from this initial work, about how multi-strain disease dynamics respond to the scale of spatial diversification in a multi-host landscape, allow us to construct a general spatially implicit model that captures these fundamental dynamics. This new model features a novel method for incorporating spatial structure using an intuitive spatial aggregation metric that can be easily estimated from spatially explicit landscape data. The model is simple enough to be amenable to mathematical invasion analysis, while being flexible enough that questions of resistance durability can be thoroughly explored. In particular, results demonstrating interaction between spatial heterogeneity and cultivar cropping ratio are presented, an investigation that was not easily possible in our earlier more complex model. These results indicate that optimal spatial deployment strategies depend on a variety of factors, and may not necessarily be constant over time. Overall, these models allow us to make general predictions of the types of system for which spatial diversification is most likely to be cost-effective, paving the way for potential economic modelling and pathosystem specific evaluation. In addition, this approach for capturing detailed spatial structure and multi-species interactions within simple mathematical models could be applied to a wide variety of ecological and evolutionary systems. This study highlights the importance of studying the effect of genetics on landscape scale spatial dynamics within host-pathogen disease systems, as well as providing new mathematical tools to do so

Processes and/of performance: difference, memory, and experimentation

This study enacts performance analyses by combining experimental and avant-garde performance practices of artists or art movements such as John Cage, Jerzy Grotowski, Dadaism, and Eugenio Barba with the differential philosophies of Jacques Derrida and Gilles Deleuze. By focusing on the ways that performance practice informs understandings of “the ghost” and différance in Derrida’s theories, and processes of production and experimentation in Deleuze’s, this study examines performance as a process of negotiating practice and theory that continues to produce rather than disappear. To reinforce the productive capacity of performance, this study looks at three different sites and the processes at work in their development as performance products: the development of the performance The Maidens, the photography exhibit The Perfect Medium: Photography and the Occult, and Marina Abramović’s performance art series Seven Easy Pieces. Within each of these sites, the processes of experimentation at work in their creation are highlighted to focus performance practice and theory on the multiple variables at work before, during, and after the “event” of performance