Evolution of self-organized division of labor in a response threshold model.

Division of labor in social insects is determinant to their ecological success. Recent models emphasize that division of labor is an emergent property of the interactions among nestmates obeying to simple behavioral rules. However, the role of evolution in shaping these rules has been largely neglected. Here, we investigate a model that integrates the perspectives of self-organization and evolution. Our point of departure is the response threshold model, where we allow thresholds to evolve. We ask whether the thresholds will evolve to a state where division of labor emerges in a form that fits the needs of the colony. We find that division of labor can indeed evolve through the evolutionary branching of thresholds, leading to workers that differ in their tendency to take on a given task. However, the conditions under which division of labor evolves depend on the strength of selection on the two fitness components considered: amount of work performed and on worker distribution over tasks. When selection is strongest on the amount of work performed, division of labor evolves if switching tasks is costly. When selection is strongest on worker distribution, division of labor is less likely to evolve. Furthermore, we show that a biased distribution (like 3:1) of workers over tasks is not easily achievable by a threshold mechanism, even under strong selection. Contrary to expectation, multiple matings of colony foundresses impede the evolution of specialization. Overall, our model sheds light on the importance of considering the interaction between specific mechanisms and ecological requirements to better understand the evolutionary scenarios that lead to division of labor in complex systems. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00265-012-1343-2) contains supplementary material, which is available to authorized users.

Spinal cord T-cell infiltration in the spared nerve injury model of neuropathic pain: a time course study

Background : Numerous studies have shown that immune cells infiltrate the spinal cord after peripheral nerve injury and that they play a major contribution to sensory hypersensitivity in rodents. In particular, the role of monocyte-derived cells and T lymphocytes seems to be prominent in this process. This exciting new perspective in research on neuropathic pain opens many different areas of work, including the understanding of the function of these cells and how they impact on neural function. However, no systematic description of the time course or cell types that characterize this infiltration has been published yet, although this seems to be the rational first step of an overall understanding of the phenomenon. Objective : Describe the time course and cell characteristics of T lymphocyte infiltration in the spinal cord in the Spared Nerve Injury (SNI) model of neuropathic pain in rats. Methods : Collect of lumbar spinal cords of rats at days 2, 7, 21 and 40 after SNI or sham operation (n=4). Immunofluorescence detecting different proteins of T cell subgroups (CD2+CD4+, CD2+CD8+, Th1 markers, Th2 markers, Th17 markers). Quantification of the infiltration rate of the different subgroups. Expected results : First, we expect to see an infiltration of T cells in the spinal cord ipsilateral to nerve injury, higher in SNI rats than in sham animals. Second, we anticipate that different subtypes of T cells penetrate at different time points. Finally, the number of T lymphocytes are expected to decrease at the latest time point, showing a resolution of the process underlying their infiltrating the spinal cord in the first place. Impact : A systematic description of the infiltration of T cells in the spinal cord after peripheral nerve injury is needed to have a better understanding of the role of immune cells in neuropathic pain. The time course that we want to establish will provide the scientific community with new perspectives. First, it will confirm that T cells do indeed infiltrate the spinal cord after SNI in rats. Second, the type of T cells infiltrating at different time points will give clues about their function, in particular their inflammatory or anti-inflammatory profile. From there on, other studies could be lead, investigating the functional side of the specific subtypes put to light by us. Ultimately, this could lead to the discovery of new drugs targeting T cells or their infiltration, in the hope of improving neuropathic pain.

Implementation of Benchmark Project Recommendations for Iowa DOT Offices of Construction, Addendum to HR-381, 1996

This report describes the continuation of the development of performance measures for the Iowa Department of Transportation (DOT) Offices of Construction. Those offices are responsible for administering transportation construction projects for the Iowa DOT. Researchers worked closely with the Benchmark Steering Team which was formed during Phase I of this project and is composed of representatives of the Offices of Construction. The research team conducted a second survey of Offices of Construction personnel, interviewed numerous members of the Offices and continued to work to improve the eight key processes identified during Phase I of this research. The eight key processes include Inspection of Work, Resolution of Technical Issues, Documentation of Work Progress and Pay Quantities, Employee Training and Development, Continuous Feedback for Improved Contract Documents, Provide Safe Traffic Control, External/Public Communication, and Providing Pre-Letting Information. Three to four measurements were specified for each key process. Many of these measurements required opinion surveys of employees, contractors, and others. During Phase II, researchers concentrated on conducting surveys, interviewing respondents to improve future surveys, and facilitating Benchmark Steering Team monthly meetings. Much effort was placed on using the information collected during the first year's research to improve the effectiveness and efficiency of the Offices of Construction. The results from Process Improvement Teams that studied Traffic Control and Resolution of Technical Issues were used to improve operations.

¿Y después del trabajo, qué? Más allá de la integración laboral de las personas con discapacidad = What happens after work? Going further than labour integration for disabled people

La actividad profesional es fundamental en la vida de cualquier persona y en el caso de las que padecen una discapacidad tiene una gran importancia para contribuir a configurar su identidad adulta. En este sentido, la finalidad del artículo es valorar la importancia del trabajo en los procesos de participación social y de calidad de vida de las personas con discapacidad. Por ello, en el artículo se pone de manifiesto la relación que se establece entre la dimensión laboral y la integración social de los individuos con discapacidad mediante el análisis de investigaciones desarrolladas en nuestro contexto, entre las que figuran diversos estudios realizados por nuestro grupo de investigación durante los últimos años. Con la voluntad de conocer con más detalle esta cuestión, se presenta una investigación reciente realizada por nuestro equipo. En ella desarrollamos un estudio de casos centrado en personas con discapacidad psíquica que han participado en experiencias de integración laboral en el mercado ordinario, con el objetivo de obtener información sobre la incidencia de la inserción laboral en diferentes dimensiones de la vida de los trabajadores con discapacidad. Los resultados nos permiten valorar que la experiencia genera cambios positivos, sobre todo a nivel personal (expectativas personales, potenciación del proyecto de vida, mejora de competencias…). Sin embargo, a pesar de que se aprecian mejoras en la dimensión social, el estudio plantea la necesidad de emprender acciones alternativas para potenciar la participación comunitaria de las personas implicadas en la investigación. El artículo concluye con algunas propuestas orientadas a mejorar los procesos de inserción social del colectivo

Work accident indemnity in Iowa, 1912

This paper on Work Accident Indemnity in Iowa, as well as the volume on the History of Work Accident Indemnity in Iowa, is the outgrowth of the author's, E. H. Downey, study of the History of Labor Legislation in Iowa, which was published by The State Historical Society of Iowa in the Iowa Economic History Series. Dealing with the vital subject of employers' liability and workmen's compensation, Professor Downey's paper will, it is thought, be found especially helpful to those interested in present day legislation. This paper was edited by Benjamen F. Shambaugh.

L'Experiència autobiogràfica, l'art i el compromís ètic de l'escriptor: tres eixos de la narrativa de Maria Àngels Anglada

L’obra de M. Àngels Anglada constitueix un tramat complex de lectures i influències que s’interpreta a través de nivells de significació i d’interessos que s’entrecreuen. Com a pilar que sosté tot aquest corpus hi ha un gran bagatge clàssic i una vasta formació literària que, juntament amb l’experiència vital i el posicionament ètic de l’autora, proporcionen les claus de lectura dels seus llibres. Partint d’aquesta idea, l’article aprofundeix en els tres aspectes que considerem eixos fonamentals de l’obra de l’escriptora: els elements autobiogràfics, l’art i el compromís social.

Evaluation of Dowel Bar Retrofits for Local Road Pavements, TR-520, 2008

As truck traffic on Iowa secondary roads has increased, engineers have moved to concrete pavements of greater depths. Early designs included thickened edge pavements and depths of seven inches or greater. The designs typically did not have load transfer devices installed in the transverse joints and relied on aggregate interlock for this purpose. In some cases, aggregate interlock was not adequate to deal with the soils and traffic conditions and faulting of the joints has begun to appear. Engineers are now faced with the need to install or retrofit load transfer in the joints to preserve the pavements. Questions associated with this decision range from the type of dowel material to dowel diameter, spacing, number of bars, placement method, and construction techniques to be used to assure reduction or elimination of faulting. Buena Vista County constructed a dowel bar retrofit project on one mile of road. The plan called for addition of the dowels (2, 3, or 4) in the outer wheel path only and surface grinding in lieu of asphalt overlay. The project included the application of elliptical- and round-shaped dowels in a rehabilitation project. Dowel material types included conventional epoxy-coated steel and fiber-reinforced polymer (FRP). This work involved the determination of relative costs in materials to be used in this type of work and performance of FRP and elliptical-shaped steel dowels in the retrofit work. The results indicate good performance from each of the bar configurations and use the results of ride and deflection testing over the research period to project the benefits that can be gained from each configuration vs. the anticipated construction costs. The reader is cautioned that this project could not relate the number of dowels required to the level of anticipated truck traffic for other roads that might be considered.

Réactualisation de la douzième conférence de consensus de la Société de réanimation de langue française (SRLF) : infections liées aux cathéters veineux centraux en réanimation [Updating of the 12th consensus conference of the Société de Réanimation de langue française (SRLF) : catheter related infections in Intensive Care unit]

Concerning catheter-related infections, many studies have been conducted until the last consensus conference of the Sociétéde réanimation de langue française (SRLF) in 1994. This text is the synthesis of the considerable amount of work performed by the experts of the society to review recent studies. The experts' texts as well as extensive bibliography are available at http://www.srlf.org.

Effectiveness of Roadway Safety Improvements, 2001

The Iowa Department of Transportation (DOT) continuously assesses the likely causes of crashes at high-crash locations throughout the Iowa roadway network and designs solutions to reduce the incidences of crashes. This research analyzed approximately 100 safety projects constructed in the past 10 years to see what affect they had on highway safety. The projects are grouped into seven categories as defined by their scope of work: (1) install new traffic signal, (2) add turn lane(s), (3) install new signal and turn lane(s), (4) add left-turn phasing, (5) add left-turn phasing and turn lane(s), (6) replace pedestal mount signals with mast arm signals, and (7) other geometric improvements. The project makes use of an extensive statewide crash database. The results of the project will evaluate the assumed reduction factors and benefit/cost (B/C) analysis, determine the actual cost effectiveness of the Iowa DOT's safety programs, and allow the Iowa DOT to better prioritize future improvements.

Traffic Management Strategies for Merge Area in Rural Interstate Work Zones, CTRE 97-12, 1999

The Iowa Department of Transportation, like many other state transportation agencies, is experiencing growing congestion and traffic delays in work zones on rural interstate highways. The congestion results in unproductive and wasteful delays for both motorists and commercial vehicles. It also results in hazardous conditions where vehicle stopped in queues on rural interstate highways are being approached by vehicles upstream at very high speeds. The delays also result in driver frustration, making some drivers willing to take unsafe risks in an effort to bypass delays. To reduce the safety hazards and unproductive delays of congested rural interstate work zones, the Iowa Department of Transportation would like to improve its traffic management strategies at these locations. Applying better management practices requires knowledge of the traffic flow properties and driver behavior in and around work zones, and knowledge of possible management strategies. The project reported here and in a companion report documents research which seeks to better understand traffic flow behavior at rural interstate highway work zones and to estimate the traffic carrying capacity of work zone lane closures. In addition, this document also reports on technology available to better manage traffic in and around work zones.