An incomplete variant of Wilson's congruence

This article examines the nontrivial solutions of the congruence $$(p-1)\cdots(p-r) \equiv -1 \pmod p.$$ We discuss heuristics for the proportion of primes $p$ that have exactly $N$ solutions to this congruence. We supply numerical evidence in favour of these conjectures, and discuss the algorithms used in our calculations.Comment: 7 pages, 2 table

Gas phase fugacity coefficients

A method is presented for calculation of fugacity coefficients in gas mixtures. This work is based on a recent paper by Leland, Gamson, and Chappelear, wherein they presented a new method for evaluation of ideal K values. The information required for the method presented here includes pure component physical properties, and generalized tables or equations for compressibility factors, fugacity coefficients, and real gas enthalpy departure terms. Pseudo-critical temperatures and pressures for the mixture are calculated using the expressions presented by Leland and Mueller. Five different binary systems consisting of paraffin hydro-carbon and CO2 mixtures containing 318 separate points were used to test this method. The results were compared with fugacity coefficients calculated from experimental data. For mixtures containing molecules of small size, this work predicts fairly accurate coefficients. For mixtures containing molecules with an appreciable difference in molecular size, the component with the larger molecule displays substantial deviations from the experimental fugacity coefficient. The one-non-hydrocarbon molecule studied, carbon dioxide, was accurately treated by this method. For binary systems containing two parraffinic components, this method will predict fugacity coefficients higher than experimental data for both components. By comparison of this method with Pitser\u27s for the same set of data, it was established that the Pitzer method was more accurate, but does require experimental data on equimolal mixtures. The method considered here requires further study to determine what modifications can be made so systems with large differences in molecular size can be accurately treated

Suicide et tentatives de suicide en prison : vulnérabilité, ostracisme et soutien social

Malgré L'attention considérable des politiques dans ce domaine, le nombre de suicides dans les prisons d'Angleterre et du pays de Galles continue de poser un problème. Suite à la prolifération des études entreprises, d'importants progrès ont été réalisés. Nous allons ici revoir les conclusions clés de différentes études menées dans plusieurs pays au cours des dix dernières années. De plus en plus, le suicide en prison est considéré comme un problème de vulnérabilité et d'adaptation, et l'on croit qu'en améliorant les politiques et les relations on pourra offrir aux prisonniers ce soutien dont ils ont un si grand besoin. Les liens entre la capacité à résoudre des problèmes, l'adaptation, le soutien social et le comportement suicidaire en prison sont évidents ; le présent article soutient donc qu'il faut aborder le suicide dans le cadre des relations sociales interpersonnelles pour arriver à le comprendre. La recherche devrait s'appuyer sur la littérature sociologique facilement disponible et qui insiste sur l'importance des réseaux sociaux au sein de la communauté carcérale. Les détenus qui constituent un risque de suicide sont souvent les plus démunis quand il s'agit d'obtenir du soutien social ou de réagir aux rares sources de soutien disponible. Parallèlement aux méthodes psychologiques et aux tests psychométriques, la recherche devrait s'appuyer sur l'ethnographie et sur les modèles qualitatifs, ainsi que sur l'examen systématique du tissu complexe des relations existantes dans la communauté carcérale. Si cet article sert de tremplin à de plus amples discussions et qu'il génère davantage de recherche, son but aura été atteint.Prison suicides in England and Wales continue and present a problem despite considerable policy attention. Research has proliferated and some important advances have been made. Key findings from studies carried out over the last decade in several countries are reviewed. Prison suicide is increasingly seen as a problem of vulnerability and coping. Improvements to regimes and relationships can offer much needed support. There are clear links between problem-solving, coping, social support and suicidal behaviour in prison. This paper argues that prison suicide needs to be understood within a framework of interpersonal social relationships. Research should draw on readily available sociological literature, which highlights the significance of social networks in the prison community. Those at risk of suicide may be least likely to have, be able to summon, or respond to scarce sources of social support. Ethnographic and other qualitative modes of research should be used to supplement psychological methods and the use of psychometric tests. The complex web of relationships that constitute the prison community should be systematically examined. The aim of the paper is to serve as a springboard for further discussion and for the generation of further research

Introducing New Approaches into Social Agencies: The Case of Behavior Modification

This paper explores the issues involved in introducing behavior modification procedures into social work agencies, sane of the common problems encountered in using this approach, and suggestions for dealing with these problems

CropEx Web-Based Agricultural Monitoring and Decision Support

CropEx is a Web-based agricultural Decision Support System (DSS) that monitors changes in crop health over time. It is designed to be used by a wide range of both public and private organizations, including individual producers and regional government offices with a vested interest in tracking vegetation health. The database and data management system automatically retrieve and ingest data for the area of interest. Another stores results of the processing and supports the DSS. The processing engine will allow server-side analysis of imagery with support for image sub-setting and a set of core raster operations for image classification, creation of vegetation indices, and change detection. The system includes the Web-based (CropEx) interface, data ingestion system, server-side processing engine, and a database processing engine. It contains a Web-based interface that has multi-tiered security profiles for multiple users. The interface provides the ability to identify areas of interest to specific users, user profiles, and methods of processing and data types for selected or created areas of interest. A compilation of programs is used to ingest available data into the system, classify that data, profile that data for quality, and make data available for the processing engine immediately upon the data s availability to the system (near real time). The processing engine consists of methods and algorithms used to process the data in a real-time fashion without copying, storing, or moving the raw data. The engine makes results available to the database processing engine for storage and further manipulation. The database processing engine ingests data from the image processing engine, distills those results into numerical indices, and stores each index for an area of interest. This process happens each time new data is ingested and processed for the area of interest, and upon subsequent database entries, the database processing engine qualifies each value for each area of interest and conducts a logical processing of results indicating when and where thresholds are exceeded. Reports are provided at regular, operator-determined intervals that include variances from thresholds and links to view raw data for verification, if necessary. The technology and method of development allow the code base to easily be modified for varied use in the real-time and near-real-time processing environments. In addition, the final product will be demonstrated as a means for rapid draft assessment of imagery

Computer Simulation of Cytoskeleton-Induced Blebbing in Lipid Membranes

Blebs are balloon-shaped membrane protrusions that form during many physiological processes. Using computer simulation of a particle-based model for self-assembled lipid bilayers coupled to an elastic meshwork, we investigated the phase behavior and kinetics of blebbing. We found that blebs form for large values of the ratio between the areas of the bilayer and the cytoskeleton. We also found that blebbing can be induced when the cytoskeleton is subject to a localized ablation or a uniform compression. The results obtained are qualitatively in agreement with the experimental evidence and the model opens up the possibility to study the kinetics of bleb formation in detail.Comment: To appear in Physical Review

Decision Support for Emergency Operations Centers

The Flood Disaster Mitigation Decision Support System (DSS) is a computerized information system that allows regional emergency-operations government officials to make decisions regarding the dispatch of resources in response to flooding. The DSS implements a real-time model of inundation utilizing recently acquired lidar elevation data as well as real-time data from flood gauges, and other instruments within and upstream of an area that is or could become flooded. The DSS information is updated as new data become available. The model generates realtime maps of flooded areas and predicts flood crests at specified locations. The inundation maps are overlaid with information on population densities, property values, hazardous materials, evacuation routes, official contact information, and other information needed for emergency response. The program maintains a database and a Web portal through which real-time data from instrumentation are gathered into the database. Also included in the database is a geographic information system, from which the program obtains the overlay data for areas of interest as needed. The portal makes some portions of the database accessible to the public. Access to other portions of the database is restricted to government officials according to various levels of authorization. The Flood Disaster Mitigation DSS has been integrated into a larger DSS named REACT (Real-time Emergency Action Coordination Tool), which also provides emergency operations managers with data for any type of impact area such as floods, fires, bom

Herschel Observations and Updated Spectral Energy Distributions of Five Sunlike Stars with Debris Disks

Observations from the Herschel Space Observatory have more than doubled the number of wide debris disks orbiting Sunlike stars to include over 30 systems with R > 100 AU. Here we present new Herschel PACS and re-analyzed Spitzer MIPS photometry of five Sunlike stars with wide debris disks, from Kuiper belt size to R > 150 AU. The disk surrounding HD 105211 is well resolved, with an angular extent of >14" along the major axis, and the disks of HD 33636, HD 50554, and HD 52265 are extended beyond the PACS PSF size (50% of energy enclosed within radius 4.23"). HD 105211 also has a 24-micron infrared excess that was previously overlooked because of a poorly constrained photospheric model. Archival Spitzer IRS observations indicate that the disks have small grains of minimum radius ~3 microns, though the minimum grain gradius is larger than the radiation pressure blowout size in all systems. If modeled as single-temperature blackbodies, the disk temperatures would all be <60 K. Our radiative transfer models predict actual disk radii approximately twice the radius of model blackbody disks. We find that the Herschel photometry traces dust near the source population of planetesimals. The disk luminosities are in the range 0.00002 <= L/L* <= 0.0002, consistent with collisions in icy planetesimal belts stirred by Pluto-size dwarf planets.Comment: Accepted for publication in ApJ. 18 pages, including 10 figures and 3 table