Literate programming on a team project

We used literate programming on a team project to write a 33,000 line program for the Synthesizer Generator. The program, Penelope, was written using WEB, a tool designed for writing literate programs. Unlike other WEB programs, many of which have been written by WEB's developer or by individuals, Penelope was not intended to be published. We used WEB in the hope that both our team and its final product would benefit from the advantages often attributed to literate programming. The WEB source served as good internal documentation throughout development and maintenance, and it continues to document Penelope's design and implementation. Our experience also uncovered a number of problems with WEB.     

Use of FEA for Design of Posttensioning Anchor Head

This paper deals with the development process of a multistrand wedge anchor head mechanism. Generally, this development process involves a number of different experimental tests but, while informative and necessary, these tests cannot provide valuable information such as internal strain distributions, stress concentrations, or percentage of the anchorage yielded volume. To answer these questions, an efficient numerical finite element model has been developed and validated which includes nonlinearities such as: large strain; plasticity; and contact between interfaces. First, this paper presents a comparison between numerical and experimental results of VSL International CS 6-31 anchorage mechanism under standard loading conditions. Based on the good agreement between results, the numerical model was then used to assess the anchorage behavior under more severe loading conditions and improved mechanical characteristics. Through anchorage deflection, von Mises stresses as well as equivalent plastic strains, it is shown that the anchor areas most severely stressed are concentrated along its peripheral wedge cavities and that, while suitable for typical loadings, the VSL anchorage is not acceptable for the more severe loading conditions examined. Finally, this paper underlines the proposed numerical model usefulness with regard to the development of new post-tensioned anchorages by providing information not otherwise available.     

Numerical and experimental validation of thermo-hygro-mechanical behaviour of wood during drying process

This research aims at developing a new approach able to simulate 3-D heat and moisture transfer coupled with the mechanical behaviour of a wood during drying process. From the moisture content and temperature profiles, a 3-D formulation and a relevant constitutive model are used to calculate the stress/strain evolution within the board due to shrinkage and external mechanical loading. This allows a fast, comprehensive and realistic model to be implemented. The mechanical model takes into account the hydrous, thermal, mechano-sorptive and elastic deformations, as well as the changes of wood properties, caused by these processes, e.g. porosity, permeability, stress–strain relation, etc. The mathematical model describing simultaneous unsteady heat and moisture transfer between a gas phase and a solid phase during heat treatment has been developed. The conservation equations for the wood sample are obtained using diffusion equation and the 3-D incompressible Navier–Stokes equations have been solved for the flow field. The constitutive equations are discussed in some detail. ANSYS-CFX10 commercial code was used to solve the hygro-thermal problem and FESh++ for the mechanical behaviour. Experimental results obtained regarding temperature, moisture content and deformation profiles during industrial drying of black spruce wood are compared with the numerical results. Satisfactory agreement is obtained over a range of drying air temperatures.     

Improving the MAC Layer of Multi-Hop Networks

Ad hoc and multi-hop networks will probably be a part of the fourth generation of wireless networks, which will integrate networks of several sizes and capacities with heterogeneous coverage: cellular networks (3G), WLAN hot spots, wireless personal area networks (WPAN) and wireless body area networks (WBAN). In this context, MAC protocols play a deciding role for a high utilization of the wireless channel. In this paper, several issues of the MAC layer and concepts for the definition of a new MAC protocol are presented. These concepts include synchronization, multi-user diversity, and multi-packet reception. It is shown that all these techniques can drastically increase the capacity of the MAC layer for multi-hop networks.     

Regional variation in adipose tissue insulin action and GLUT4 glucose transporter expression in severely obese premenopausal women

Insulin action and GLUT4 expression were examined in adipose tissue of severely obese premenopausal women undergoing gastrointestinal surgery. Fat samples were taken from three different anatomical regions: the subcutaneous abdominal site, the round ligament (deep abdominal properitoneal fat), and the greater omentum (deep abdominal intraperitoneal fat). The stimulatory effect of insulin on glucose transport and the ability of the hormone to inhibit lipolysis were determined in adipocytes isolated from these three adipose depots. Insulin stimulated glucose transport 2-3 times over basal rates in all adipocytes. However, round ligament adipose cells showed a significantly greater responsiveness to insulin when compared to subcutaneous and omental adipocytes. Round ligament fat cells also displayed the greatest sensitivity and maximal antilipolytic response to insulin. We also investigated whether regional differences in fat cell insulin-stimulated glucose transport were linked to a differential expression of the GLUT4 glucose transporter. GLUT4 protein content in total membranes was 5 and 2.2 times greater in round ligament adipose tissue than in subcutaneous and omental fat depots, respectively. Moreover, GLUT4 mRNA levels were 2.1 and 3 times higher in round ligament than in subcutaneous or omental adipose tissues, respectively. Adipose tissue GLUT4 protein content was strongly and negatively associated (r = -0.79 to -0.89, p < 0.01) with the waist-to-hip ratio but not with total adiposity. In conclusion, these results demonstrate the existence of site differences in adipose tissue insulin action in morbidly obese women. The greater insulin effect on glucose transport in round ligament adipocytes was associated with a higher expression of GLUT4 when compared to subcutaneous abdominal and omental fat cells. Moreover, despite the regional variation in GLUT4 expression, an increased proportion of abdominal fat was found to be associated with lower levels of GLUT4 in all adipose regions investigated.     

First-contact incidence rates of schizophrenia in Trinidad and one-year follow-up

BACKGROUND: Incidence rates of schizophrenia among UK African-Caribbeans have been reported as high. Various explanations including selective migration and genetic vulnerability have been proposed. METHOD: In one calendar year, all new cases of psychosis presenting to various psychiatric services in two clearly defined geographical catchment areas in Trinidad-one in the rural south and the other an urban area-were studied. Standardised diagnostic instruments were applied and information collected using WHO screening and measurement instruments. RESULTS: A total of 56 cases were collected, giving an incidence rate of 2.2/1000 of broad schizophrenia with a rate of 1.6 for S+ schizophrenia. CONCLUSION: These rates are similar to those from the WHO study in Honolulu and Aarhus, and much lower than the rates for African-Caribbeans in London. The cases were followed up for one year and the poor outcome rate for schizophrenia was 19%. The findings are discussed in a cross-cultural context and suggestions for future research made.     

Sur l'importance des hétérogénéités du sous-sol en électrodépollution

Des études expérimentales de dépollution par méthode électrocinétique de sols contaminés nous ont révélé que d'excellents résultats peuvent être obtenus avec des sols argileux homogènes et pollués par du Cd, tant lors d'essais en cellules qu'en s'assujettissant de l'effet d'échelle lors d'essais pilotes conduits sur plus de 3 tonnes de matériaux. Par contre l'introduction d'une discontinuité de stratification, par exemple la superposition de deux couches d'argile légèrement différentes, toutes deux polluées de manière identique, nous montre que le taux de dépollution chute immédiatement, la cause en étant l'introduction d'une hétérogénéité de stratification. D'autres types d'hétérogénéités fortes ou diffuses vont probablement poser problème. Ceci tend à atténuer l'intérêt de la méthode d'électrodépollution dans son application directe sur le terrain.     

CROMA – An Enhanced Slotted MAC Protocol for MANETs

TDMA based MAC protocols can provide a very good utilization of the shared radio resources, especially at high input loads, in synchronized mobile ad hoc networks (MANETs). Global positioning systems like GPS or GALLILEO should provide a very good timing accuracy for synchronization of nodes. This paper presents a new medium access protocol for mobile ad hoc networks, called CROMA. CROMA is collision-free and receiver-oriented. It operates in a slotted environment, in a dynamic and distributed way. In this protocol, receivers act as local base stations and can manage one or several communications on a single slot. Thus, sophisticated functions are allowed at higher layers. Moreover, the hidden terminal as well as the exposed terminal problems are handled by CROMA. A theoretical analysis and extensive simulations show that CROMA can reach very high throughputs.     

Down-regulation of interleukin-1beta production and PGE2 accumulation by an indomethacin-phenylalanine derivative in human monocytes

This study was initiated to investigate the mechanism of action of a new indomethacin derivative, indomethacin-phenylalanine (indo-Phe) in human monocytes. We determined the effect of indo-Phe on the induction by LPS of prostaglandin-E2 (PGE2) and interleukin-1beta (IL-1beta) production in human monocytes. Indomethacin and indo-Phe inhibited the PGE2 synthesis in treated and untreated IL-1beta or LPS-treated monocytes. Furthermore, in IL-1beta and LPS-treated monocytes, prostaglandin G/H synthase-1 (PGHS-1) protein expression was down-regulated with indomethacin or its indo-Phe analog whereas the level of the inducible protein (PGHS-2) was up-regulated. We analyzed the effect of indomethacin and indo-Phe on the expression of IL-1beta protein in LPS-treated monocytes and found that indo-Phe blocked the LPS-induction of IL-1beta synthesis while indomethacin did not. These differential effects of indomethacin and indo-Phe suggest that two independent ways are involved in the stimulation of monocytes by LPS: the PGHS-2 protein induction and the IL-1beta secretion.