World city network research at a theoretical impasse::On the need to re-establish qualitative approaches to understanding agency in world city networks

From the late 1990s, the establishment of a new relational ‘turn’ in the study of world city connectedness in globalization has run parallel to the wider relational turn occurring in economic geography. Early work, built firmly upon a qualitative approach to the collection and analyses of new inter-city datasets, considered cities as being constituted by their relations with other cities. Subsequent research, however, would take a strong quantitative turn, best demonstrated through the articulation of the inter-locking world city network (ILWCN) ‘model’ for measuring relations between cities. In this paper, we develop a critique of research based around the ILWCN model, arguing that this ‘top down’ quantitative approach has now reached a theoretical impasse. To address this impasse, we argue for a move away from Structural approaches in which the firm is the main unit of analysis, towards qualitative approaches in which individual agency and practice are afforded greater importance

Electron scattering in ethene: Excitation of the ã 3B1u state, elastic scattering, and vibrational excitation

Experimental and calculated absolute differential cross sections for the scattering of low-energy electrons from ethene are presented. Emphasis is on the excitation of the ã 3B1u 3(pi,pi*) state, but selected elastic and vibrational excitation cross sections are also given. In contrast to earlier calculations, which were nearly a factor of 2 too large, the present calculation agrees very well with the experimental triplet excitation cross section in the threshold region. The improvement is due primarily to the inclusion of target polarization, which results in proper positioning of the pi* resonance, whose high-energy tail dominates the triplet state excitation near threshold. The present experimental elastic cross sections agree very well with recent calculations taking into account target polarization

Absolute angle-differential elastic cross sections for electron collisions with diacetylene

We report measured and calculated differential elastic cross sections for collisions of low-energy electrons with diacetylene (1,3-butadiyne). A generally satisfactory agreement between theory and experiment has been found. The calculated cross sections provide interesting insight into the underlying resonant structure

Biophysical Fitness Landscapes for Transcription Factor Binding Sites

Evolutionary trajectories and phenotypic states available to cell populations are ultimately dictated by intermolecular interactions between DNA, RNA, proteins, and other molecular species. Here we study how evolution of gene regulation in a single-cell eukaryote S. cerevisiae is affected by the interactions between transcription factors (TFs) and their cognate genomic sites. Our study is informed by high-throughput in vitro measurements of TF-DNA binding interactions and by a comprehensive collection of genomic binding sites. Using an evolutionary model for monomorphic populations evolving on a fitness landscape, we infer fitness as a function of TF-DNA binding energy for a collection of 12 yeast TFs, and show that the shape of the predicted fitness functions is in broad agreement with a simple thermodynamic model of two-state TF-DNA binding. However, the effective temperature of the model is not always equal to the physical temperature, indicating selection pressures in addition to biophysical constraints caused by TF-DNA interactions. We find little statistical support for the fitness landscape in which each position in the binding site evolves independently, showing that epistasis is common in evolution of gene regulation. Finally, by correlating TF-DNA binding energies with biological properties of the sites or the genes they regulate, we are able to rule out several scenarios of site-specific selection, under which binding sites of the same TF would experience a spectrum of selection pressures depending on their position in the genome. These findings argue for the existence of universal fitness landscapes which shape evolution of all sites for a given TF, and whose properties are determined in part by the physics of protein-DNA interactions

The Michigan Disability Prevention Study: Research Highlights

This 3-year collaborative research project was designed to provide empirical evidence to substantiate the impact of various employer policies and practices on the prevention and management of workplace disability. It studied a random sample of 220 Michigan establishments with more than 100 employees from seven different industries who responded to a mail survey in the first half of 1991. The study correlates differences in employer-reported levels of achievement on policy and practice dimensions with performance on disability outcome measures, while controlling for a set of establishment characteristics in a multivariate regression analysis. There are three sets of policy and practice interventions evaluated here. First is safety intervention, that is, the attempt to prevent injuries from happening at all (measured as Safety Diligence, Ergonomic Solutions, and Safety Training). Second is disability management, the set of strategies to minimize the disability consequences of a given injury or disease arising from the workplace (measured as Disability Case Monitoring and Proactive Return-to-Work Program). Third is health promotion, which represents an attempt to intervene directly with individuals to encourage more healthy lifestyles, in the expectation that this will reduce the likelihood of a workplace accident or disease, or reduce the lost worktime resulting from a given injury or disease (measured as Wellness Orientation). In addition, a fourth dimension was included to capture the general environment of the firm and the orientation of its management in areas relevant to the study (measured as People Oriented Culture and Active Safety Leadership). These interventions and the general environment of the firm were scored on this set of eight variables which represent self-rated firm achievement of the policy and practice dimensions. The marginal effect of these interventions is determined by comparing firm performance on the incidence of work-related disability (Lost Workday Cases and Workers' Compensation Wage-Loss Claims), the duration of disability (Lost Workdays per Case), and overall disability prevention and management performance (Total Lost Workdays). Our results show that a higher self-rating on Safety Diligence is strongly associated with better performance on disability outcomes, varying with the specific measure. Higher self-rating on Proactive Return-to-Work Programs is also strongly associated with better performance outcomes. Safety Training and Active Safety Leadership is shown to have significant effects on the number of Lost Workday Cases. For example, on the summary measure of total Lost Workdays per 100 Employees, 10 percent better self-rating on Safety Diligence translates into 17 percent fewer lost workdays, and 10 percent better self-rating on Proactive Return-to-Work Programs translates into 7 percent fewer lost workdays. Thus, the twin strategies of trying to prevent injuries in the first place, and working to ameliorate their disability effects through disability management techniques, are both shown to be productive in reducing workplace disability in those establishments that have implemented them rigorously. Disability Case Monitoring could not be shown to have significant effects; in fact, Disability Case Monitoring had negative impacts in some cases. This probably reflects the controlling aspects of Disability Case Monitoring, as we speculate that these practices can be viewed by the employees as negative and interfering if they do not emanate from a supportive company human resource climate. Ergonomic Solutions and Wellness Orientation generally do not perform significantly, and this is attributed to their indirect connection to the performance outcomes used here or ineffective measurement of these dimensions in the study. Site visits were made to a subsample of 32 firms selected from the larger, random sample in order to confirm the quantitative survey findings and gain operational understanding of successful policies and practices contributing to low disability rates. Companies were generally found to be most advanced in their safety efforts, very active in injury management, and had implemented at least some form of return-to-work. Health promotion strategies to prevent specific work injuries have not yet been fully developed. The disability prevention efforts of successful firms use data effectively to measure performance, identify problems, guide actions taken, and motivate active support and participation of management, supervisors and line employees. Successful firms rigorously investigate injuries and communicate their commitment by immediately responding to risks when they are identified. In these low-disability firms, safety and disability management are viewed as components of quality, productivity and financial stability. Working relationships have been developed with responsive health care providers to assure effective injury management, but firms also maintain an active role in case management themselves. Their return-to-work process is systematic, yet flexible to respond to individual needs. Innovative firms have also implemented ergonomic principles to prevent risks. Nearly all companies visited reported increasing incidence and costs due to cumulative trauma and repetitive motion disorders. Additional strategies are needed to resolve and prevent these disabilities. This study demonstrates that many employers have moved aggressively to policies and practices designed to reduce the incidence and the costs of disability in their workplace. The project concludes that disability can be prevented and managed; and those who do it well can expect to be rewarded with lower disability costs, more satisfied workers, higher productivity and, ultimately, higher profits.disability, workers', compensation, Michigan, Hunt, Habeck

Thermalization of Squeezed States

Starting with a thermal squeezed state defined as a conventional thermal state based on an appropriate hamiltonian, we show how an important physical property, the signal-to-noise ratio, is degraded, and propose a simple model of thermalization (Kraus thermalization).Comment: 7 pages, 1 table, 1 figure. Presented at ICSSUR 2005, Besancon, Franc

Disability Prevention Among Michigan Employers

This chapter briefly discusses the magnitude of the problem of disability in the workplace. It also presents an overview of the three and one-half year research project for which this Final Report is the product. It highlights the origins of the project and the major design elements that are reflected in this report. It concludes with a discussion of the remaining limitations of the research

OPTIMAL HOG SLAUGHTER WEIGHTS UNDER ALTERNATIVE PRICING SYSTEMS

Three hog genotypes are simulated to determine how producer profits, economically optimal slaughter weights, and carcass component weights change under three pricing models. Live weight pricing pays more for the fatter barrows whereas a three component (separate payments for fat, lean, and byproducts) and six component (separate payments for major primal cuts, other lean, fat, and byproducts) pricing system pay more for the leaner gilts. Implications for selection of genetic stock and pricing system are presented.Swine production management, Hog pricing systems, Hog marketing, Livestock Production/Industries,