Dilaton Contact Terms in the Bosonic and Heterotic Strings

Dilaton contact terms in the bosonic and heterotic strings are examined following the recent work of Distler and Nelson on the bosonic and semirigid strings. In the bosonic case dilaton two-point functions on the sphere are calculated as a stepping stone to constructing a `good' coordinate family for dilaton calculations on higher genus surfaces. It is found that dilaton-dilaton contact terms are improperly normalized, suggesting that the interpretation of the dilaton as the first variation of string coupling breaks down when other dilatons are present. It seems likely that this can be attributed to the tachyon divergence found in \TCCT. For the heterotic case, it is found that there is no tachyon divergence and that the dilaton contact terms are properly normalized. Thus, a dilaton equation analogous to the one in topological gravity is derived and the interpretation of the dilaton as the string coupling constant goes through.Comment: 44 pages, Figures now included. This replacement version includes the 7 figures as PostScript files appended to the end and the macros to insert them into the text. Also some typos in intermediate formulae were correcte

Jurassic Greenways: Planning a Dinosaur Trail for the Connecticut River Valley

Greenways often combine natural, historic/cultural, and recreational resources (Fábos 1995). However, there has been less integration with scientific interpretation, particularly in the area of paleontology and geology, except for a few notable examples. The current threat of global climate compels a look back in geologic time to how different landscapes, ecosystems, and human settlements evolved and adapted to rapidly changing climatic and environmental conditions. This study involves research and project development of a greenway and trail network that connects the important historical and cultural sites related to dinosaurs in New England’s Connecticut River Valley of Massachusetts and Connecticut (USA). The project is a partnership of museums, cultural sites, and tourist businesses related to the discovery of dinosaur tracks and other significant paleo-geologic sites (www.jurassicroadshow.com). The lead organization, the Pocumtuck Valley Memorial Association, a historic museum in Deerfield, MA (www.deerfieldma. org), is developing an interactive web-site called the Impressions from a Lost World that is the beginning point for this project, which was conducted as part of a graduate landscape architecture studio at the University of Massachusetts, Amherst under the direction of Professor Robert L. Ryan

Ethical approval for national studies in Ireland: an illustration of current challenges.

BACKGROUND: Ethical approval of research projects is, appropriately, an essential prerequisite in health settings. AIMS: This paper outlines difficulties encountered with procedures for gaining ethical approval for two multicentre surveys in Ireland. METHODS: The experiences of two national surveys were documented. RESULTS: Delays in processing ethics applications led to substantial delays in both surveys. Research ethics committees (RECs) assessed applications in an idiosyncratic manner. CONCLUSION: In Ireland, there is currently no accepted mechanism for single location ethical approval for multicentre studies. Instead, they require separate approval from all participating centres. The challenges of this system of application to multiple committees are outlined in this paper, and possible solutions presented

Optimizing the scale of markets for water quality trading

Applying market approaches to environmental regulations requires establishing a spatial scale for trading. Spatially large markets usually increase opportunities for abatement cost savings but increase the potential for pollution damages (hot spots), vice versa for spatially small markets. We develop a coupled hydrologic-economic modeling approach for application to point source emissions trading by a large number of sources and apply this approach to the wastewater treatment plants (WWTPs) within the watershed of the second largest estuary in the U.S. We consider two different administrative structures that govern the trade of emission permits: one-for-one trading (the number of permits required for each unit of emission is the same for every WWTP) and trading ratios (the number of permits required for each unit of emissions varies across WWTP). Results show that water quality regulators should allow trading to occur at the river basin scale as an appropriate first-step policy, as is being done in a limited number of cases via compliance associations. Larger spatial scales may be needed under conditions of increased abatement costs. The optimal scale of the market is generally the same regardless of whether one-for-one trading or trading ratios are employed

World-Sheet Supersymmetry Without Contact Terms

Green and Seiberg showed that, in simple treatments of fermionic string theory, it is necessary to introduce contact interactions when vertex operators collide. Otherwise, certain superconformal Ward identities would be violated. In this note, we show how these contact terms arise naturally when proper account is taken of the superconformal geometry involved when punctures collide. More precisely, we show that there is no contact term at all! Rather, corrections arise to the ``na\"\i ve" formula when the boundary of moduli space is described correctly.Comment: 14pp., 2 figures (included

Increase in observed mental health difficulties one year after acute coronary syndrome: general practitioner survey.

BACKGROUND: General practitioners (GPs) are often the first to assess mental health difficulties after acute coronary syndrome (ACS). AIMS: To determine whether GPs observed an increase in mental health difficulties one-year post-hospitalisation for ACS. METHODS: Postal survey. RESULTS: GPs rated patients (n = 442) as having probable (GP assessed 10%) or definite (formally assessed 7%) mental health difficulties pre-hospitalisation. Post-hospitalisation the prevalence of probable cases increased significantly to 19% (OR = 4.3, 95% CI 2.1-10.2, P \u3c 0.001). In multivariate analysis, only smoking at index hospitalisation was associated with being assessed as a new case of probable/formal mental health difficulties (RR = 2.1, 95% CI 1.3-3.4, P = 0.003). Forty-seven percent of cases were prescribed some medication for this problem. CONCLUSIONS: GPs recorded a significant increase in mental health difficulties in ACS patients 12 months after hospitalisation, with smoking used as an indicator of new cases

The Hospital Anxiety and Depression Scale depression subscale, but not the Beck Depression Inventory-Fast Scale, identifies patients with acute coronary syndrome at elevated risk of 1-year mortality.

OBJECTIVE: The objective of this study was to investigate the use of short-form depression scales in assessing 1-year mortality risk in a national sample of patients with acute coronary syndrome (ACS). METHODS: Patients with ACS (N=598) completed either the Hospital Anxiety and Depression Scale depression subscale (HADS-D) or the Beck Depression Inventory-Fast Scale (BDI-FS). Their mortality status was assessed at 1 year. RESULTS: Cox proportional hazards modeling showed that patients depressed at baseline (combining HADS-D and BDI-FS depressed cases) were more likely to die within 1 year [hazard ratio (HR)=2.8, 95% CI=1.4-5.7, P=.005], even when controlling for major medical and demographic variables (HR=4.1, 95% CI=1.6-10.3, P=.003). Scoring above the threshold on the HADS-D predicted mortality (HR=4.2, 95% CI=1.8-10.0, P=.001), but scoring above the threshold on the BDI-FS did not (HR=1.8, 95% CI=0.6-5.6, P=.291). CONCLUSION: The HADS-D predicted increased risk of 1-year mortality in patients with ACS