Loop Corrections and Naturalness in a Chiral Effective Field Theory

The loop expansion is applied to a chiral effective hadronic lagrangian; with the techniques of Infrared Regularization, it is possible to separate out the short-range contributions and to write them as local products of fields that are already present in our lagrangian. (The appropriate field variables must be re-defined at each order in loops.) The corresponding parameters implicitly include short-range effects to all orders in the interaction, so these effects need not be calculated explicitly. The remaining (long-range) contributions that must be calculated are nonlocal and resemble those in conventional nuclear-structure calculations. Nonlinear isoscalar scalar $(\sigma)$ and vector $(\omega)$ meson interactions are included, which incorporate many-nucleon forces and nucleon substructure. Calculations are carried out at the two-loop level to illustrate these techniques at finite nuclear densities and to verify that the coupling parameters remain natural when fitted to the empirical properties of equilibrium nuclear matter. Contributions from the $\omega N$ tensor coupling are also discussed.Comment: 22 pages, 6 figure

The Importance of the Study of Medical Sociology

This 1894 article by a physician discusses the relationshp between the medical profession and the general field of sociology

Design of a neural network simulator on a transputer array

A brief summary of neural networks is presented which concentrates on the design constraints imposed. Major design issues are discussed together with analysis methods and the chosen solutions. Although the system will be capable of running on most transputer architectures, it currently is being implemented on a 40-transputer system connected to a toroidal architecture. Predictions show a performance level equivalent to that of a highly optimized simulator running on the SX-2 supercomputer

Reforming Cote d'Ivoire's cocoa marketing and pricing system

Cote d'Ivoire has historically taxed cocoa producers. Market reforms over the past 10 years have somewhat succeeded in making domestic and foreign marketing more transparent and competitive. But they have not done much to raise producer prices in real terms or as a share of the FOB (free on board) price. Maintaining fixed producer prices and marketing costs and margins has encouraged rent-seeking and led to efficiency losses. New reform will fully liberalize the country's export marketing system by eliminating public management of exports. This means the end of mandatory export authorization, of public forward sales, and of fixed minimum producer prices and marketing margins. The new reform is expected to improve producers'incomes. The authors find that the benefits from the new reform (in terms of lower implicit taxes, lower marketing costs and margins, and higher producer prices) will outweigh the costs from eliminating public forward sales and fixed producer prices. Results from a general equilibrium model indicate that reducing export taxes would have a small negative effect on aggregate income but would improve income distribution for poorer rural areas. The fact that Cote d'Ivoire has market power in the world cocoa market justifies a higher optimal export tax than the current one. But raising export taxes may eventually reduce its market share and worsen income distribution, at the expense of the poorer rural sector.Payment Systems&Infrastructure,Economic Theory&Research,Environmental Economics&Policies,Markets and Market Access,Labor Policies,Consumption,Markets and Market Access,Access to Markets,Economic Theory&Research,Environmental Economics&Policies

Allocation of livestock research resources in sub-Saharan Africa

Describes possible methods of allocating research resources based on different analytical models. Presents a brief review of models proposed; and some evidence about current agricultural and livestock reserch in sub-Saharan Africa. Also presents emperical tests of which variables might be important in defining the research priorities in 32 of ILCA's mandate countries. Compares ILCA's current allocation of funds and those suggested by the models

Shear stress induced stimulation of mammalian cell metabolism

A flow apparatus was developed for the study of the metabolic response of anchorage dependent cells to a wide range of steady and pulsatile shear stresses under well controlled conditions. Human umbilical vein endothelial cell monolayers were subjected to steady shear stresses of up to 24 dynes/sq cm, and the production of prostacyclin was determined. The onset of flow led to a burst in prostacyclin production which decayed to a long term steady state rate (SSR). The SSR of cells exposed to flow was greater than the basal release level, and increased linearly with increasing shear stress. It is demonstrated that shear stresses in certain ranges may not be detrimental to mammalian cell metabolism. In fact, throughout the range of shear stresses studied, metabolite production is maximized by maximizing shear stress

The Correlation Between Perceptions of Safety and Perceived Stress Among Residents of the Somerset Neighborhood of Kensington, Philadelphia

Background: The Somerset neighborhood of Kensington, Philadelphia is affected by economic, environmental, and social issues that come with disinvestment. The average median income for Somerset is $26,015 per year which is much lower than Philadelphia’s city-wide income of$36, 957. This study evaluated the connection between perceptions of safety and perceived stress among residents of the Somerset neighborhood. Methods: This study was a secondary data analysis from a cross-sectional study in the Somerset neighborhood. The data included self-reported surveys from Somerset residents that were completed at their homes. The surveys were completed using an electronic (tablet) format which took approximately 20 to 30 minutes to complete. Trained members of the neighborhood collected the data from July to December 2017. We used SPSS to quantify relationships between perceptions of safety and perceived stress using Spearman’s Rank Order Correlation for each of our 12 perceptions of safety variables and stress. Our final model was created using a multivariable linear regression model. Results: We had 328 adults with an average age of 48 years old in our study sample. We found that most of the residents were female, 35.3% were Latino, predominantly single, and mainly employed full-time. Additionally, over half of the residents owned their home and 16 years was the average amount of time lived in the neighborhood. We found that the average score on the stress scale was a 5.18 (range 0-16). In our final model, we found 4 variables to be statistically significant (α= .10) age, years lived in the community, police should spend more time working with community members and groups to solve problems, and members of my community are interested in crime prevention activities. Discussion: Overall, the mean stress levels were lower than we expected. We found associations between demographics and perceptions of safety variables specifically, as age increased, stress decreased and as the years lived in the community increased, stress increased. Our results also indicated as police spent more time working with community members and as crime prevention activities increased in the community, stress decreased. The strongest predictor of stress was the variable: “police should spend more time working with community members and groups to solve problems.” Collaborations between police officers and community members have the potential to improve health and may also help residents feel safer and less stressed in the neighborhood