Evolutionary games on complex networks : the emergence and maintenance of cooperation

Abstract The object of game theory lies in the analysis of situations where different social actors have conflicting requirements and where their individual decisions will all influence the global outcome. In this framework, several games have been invented to capture the essence of various dilemmas encountered in many common important socio-economic situations. Even though these games often succeed in helping us understand human or animal behavior in interactive settings, some experiments have shown that people tend to cooperate with each other in situations for which classical game theory strongly recommends them to do the exact opposite. Several mechanisms have been invoked to try to explain the emergence of this unexpected cooperative attitude. Among them, repeated interaction, reputation, and belonging to a recognizable group have often been mentioned. However, the work of Nowak and May (1992) showed that the simple fact of arranging the players according to a spatial structure and only allowing them to interact with their immediate neighbors is sufficient to sustain a certain amount of cooperation even when the game is played anonymously and without repetition. Nowak and May's study and much of the following work was based on regular structures such as two-dimensional grids. Axelrod et al. (2002) showed that by randomizing the choice of neighbors, i.e. by actually giving up a strictly local geographical structure, cooperation can still emerge, provided that the interaction patterns remain stable in time. This is a first step towards a social network structure. However, following pioneering work by sociologists in the sixties such as that of Milgram (1967), in the last few years it has become apparent that many social and biological interaction networks, and even some technological networks, have particular, and partly unexpected, properties that set them apart from regular or random graphs. Among other things, they usually display broad degree distributions, and show small-world topological structure. Roughly speaking, a small-world graph is a network where any individual is relatively close, in terms of social ties, to any other individual, a property also found in random graphs but not in regular lattices. However, in contrast with random graphs, small-world networks also have a certain amount of local structure, as measured, for instance, by a quantity called the clustering coefficient. In the same vein, many real conflicting situations in economy and sociology are not well described neither by a fixed geographical position of the individuals in a regular lattice, nor by a random graph. Furthermore, it is a known fact that network structure can highly influence dynamical phenomena such as the way diseases spread across a population and ideas or information get transmitted. Therefore, in the last decade, research attention has naturally shifted from random and regular graphs towards better models of social interaction structures. The primary goal of this work is to discover whether or not the underlying graph structure of real social networks could give explanations as to why one finds higher levels of cooperation in populations of human beings or animals than what is prescribed by classical game theory. To meet this objective, I start by thoroughly studying a real scientific coauthorship network and showing how it differs from biological or technological networks using divers statistical measurements. Furthermore, I extract and describe its community structure taking into account the intensity of a collaboration. Finally, I investigate the temporal evolution of the network, from its inception to its state at the time of the study in 2006, suggesting also an effective view of it as opposed to a historical one. Thereafter, I combine evolutionary game theory with several network models along with the studied coauthorship network in order to highlight which specific network properties foster cooperation and shed some light on the various mechanisms responsible for the maintenance of this same cooperation. I point out the fact that, to resist defection, cooperators take advantage, whenever possible, of the degree-heterogeneity of social networks and their underlying community structure. Finally, I show that cooperation level and stability depend not only on the game played, but also on the evolutionary dynamic rules used and the individual payoff calculations. Synopsis Le but de la th��orie des jeux r��side dans l'analyse de situations dans lesquelles diff��rents acteurs sociaux, avec des objectifs souvent conflictuels, doivent individuellement prendre des d��cisions qui influenceront toutes le r��sultat global. Dans ce cadre, plusieurs jeux ont ��t�� invent��s afin de saisir l'essence de divers dilemmes rencontr��s dans d'importantes situations socio-��conomiques. Bien que ces jeux nous permettent souvent de comprendre le comportement d'��tres humains ou d'animaux en interactions, des exp��riences ont montr�� que les individus ont parfois tendance �� coop��rer dans des situations pour lesquelles la th��orie classique des jeux prescrit de faire le contraire. Plusieurs m��canismes ont ��t�� invoqu��s pour tenter d'expliquer l'��mergence de ce comportement coop��ratif inattendu. Parmi ceux-ci, la r��p��tition des interactions, la r��putation ou encore l'appartenance �� des groupes reconnaissables ont souvent ��t�� mentionn��s. Toutefois, les travaux de Nowak et May (1992) ont montr�� que le simple fait de disposer les joueurs selon une structure spatiale en leur permettant d'interagir uniquement avec leurs voisins directs est suffisant pour maintenir un certain niveau de coop��ration m��me si le jeu est jou�� de mani��re anonyme et sans r��p��titions. L'��tude de Nowak et May, ainsi qu'un nombre substantiel de travaux qui ont suivi, ��taient bas��s sur des structures r��guli��res telles que des grilles �� deux dimensions. Axelrod et al. (2002) ont montr�� qu'en randomisant le choix des voisins, i.e. en abandonnant une localisation g��ographique stricte, la coop��ration peut malgr�� tout ��merger, pour autant que les sch��mas d'interactions restent stables au cours du temps. Ceci est un premier pas en direction d'une structure de r��seau social. Toutefois, suite aux travaux pr��curseurs de sociologues des ann��es soixante, tels que ceux de Milgram (1967), il est devenu clair ces derni��res ann��es qu'une grande partie des r��seaux d'interactions sociaux et biologiques, et m��me quelques r��seaux technologiques, poss��dent des propri��t��s particuli��res, et partiellement inattendues, qui les distinguent de graphes r��guliers ou al��atoires. Entre autres, ils affichent en g��n��ral une distribution du degr�� relativement large ainsi qu'une structure de "petit-monde". Grossi��rement parlant, un graphe "petit-monde" est un r��seau o�� tout individu se trouve relativement pr��s de tout autre individu en termes de distance sociale, une propri��t�� ��galement pr��sente dans les graphes al��atoires mais absente des grilles r��guli��res. Par contre, les r��seaux "petit-monde" ont, contrairement aux graphes al��atoires, une certaine structure de localit��, mesur��e par exemple par une quantit�� appel��e le "coefficient de clustering". Dans le m��me esprit, plusieurs situations r��elles de conflit en ��conomie et sociologie ne sont pas bien d��crites ni par des positions g��ographiquement fixes des individus en grilles r��guli��res, ni par des graphes al��atoires. De plus, il est bien connu que la structure m��me d'un r��seau peut passablement influencer des ph��nom��nes dynamiques tels que la mani��re qu'a une maladie de se r��pandre �� travers une population, ou encore la fa��on dont des id��es ou une information s'y propagent. Ainsi, durant cette derni��re d��cennie, l'attention de la recherche s'est tout naturellement d��plac��e des graphes al��atoires et r��guliers vers de meilleurs mod��les de structure d'interactions sociales. L'objectif principal de ce travail est de d��couvrir si la structure sous-jacente de graphe de vrais r��seaux sociaux peut fournir des explications quant aux raisons pour lesquelles on trouve, chez certains groupes d'��tres humains ou d'animaux, des niveaux de coop��ration sup��rieurs �� ce qui est prescrit par la th��orie classique des jeux. Dans l'optique d'atteindre ce but, je commence par ��tudier un v��ritable r��seau de collaborations scientifiques et, en utilisant diverses mesures statistiques, je mets en ��vidence la mani��re dont il diff��re de r��seaux biologiques ou technologiques. De plus, j'extrais et je d��cris sa structure de communaut��s en tenant compte de l'intensit�� d'une collaboration. Finalement, j'examine l'��volution temporelle du r��seau depuis son origine jusqu'�� son ��tat en 2006, date �� laquelle l'��tude a ��t�� effectu��e, en sugg��rant ��galement une vue effective du r��seau par opposition �� une vue historique. Par la suite, je combine la th��orie ��volutionnaire des jeux avec des r��seaux comprenant plusieurs mod��les et le r��seau de collaboration susmentionn��, afin de d��terminer les propri��t��s structurelles utiles �� la promotion de la coop��ration et les m��canismes responsables du maintien de celle-ci. Je mets en ��vidence le fait que, pour ne pas succomber �� la d��fection, les coop��rateurs exploitent dans la mesure du possible l'h��t��rog��n��it�� des r��seaux sociaux en termes de degr�� ainsi que la structure de communaut��s sous-jacente de ces m��mes r��seaux. Finalement, je montre que le niveau de coop��ration et sa stabilit�� d��pendent non seulement du jeu jou��, mais aussi des r��gles de la dynamique ��volutionnaire utilis��es et du calcul du b��n��fice d'un individu.

Effective Shoulder Design and Maintenance, 2007

Granular shoulders are an important element of the transportation system and are constantly subjected to performance problems due to wind- and water-induced erosion, rutting, edge drop-off, and slope irregularities. Such problems can directly affect drivers��� safety and often require regular maintenance. The present research study was undertaken to investigate the factors contributing to these performance problems and to propose new ideas to design and maintain granular shoulders while keeping ownership costs low. This report includes observations made during a field reconnaissance study, findings from an effort to stabilize the granular and subgrade layer at six shoulder test sections, and the results of a laboratory box study where a shoulder section overlying a soft foundation layer was simulated. Based on the research described in this report, the following changes are proposed to the construction and maintenance methods for granular shoulders: ��� A minimum CBR value for the granular and subgrade layer should be selected to alleviate edge drop-off and rutting formation. ��� For those constructing new shoulder sections, the design charts provided in this report can be used as a rapid guide based on an allowable rut depth. The charts can also be used to predict the behavior of existing shoulders. ��� In the case of existing shoulder sections overlying soft foundations, the use of geogrid or fly ash stabilization proved to be an effective technique for mitigating shoulder rutting.

Appropriateness of respiratory care: evidence-based guidelines.

PRINCIPLES: Respiratory care is universally recognised as useful, but its indications and practice vary markedly. In order to improve the appropriateness of respiratory care in our hospital, we developed evidence-based local guidelines in a collaborative effort involving physiotherapists, physicians and health service researchers. METHODS: Recommendations were developed using the standardised RAND appropriateness method. A literature search was conducted based on terms associated with guidelines and with respiratory care. A working group prepared proposals for recommendations which were then independently rated by a multidisciplinary expert panel. All recommendations were then discussed in common and indications for procedures were rated confidentially a second time by the experts. The recommendations were then formulated on the basis of the level of evidence in the literature and on the consensus among these experts. RESULTS: Recommendations were formulated for the following procedures: non-invasive ventilation, continuous positive airway pressure, intermittent positive pressure breathing, intrapulmonary percussive ventilation, mechanical insufflation-exsufflation, incentive spirometry, positive expiratory pressure, nasotracheal suctioning and non-instrumental airway clearance techniques. Each recommendation referred to a particular medical condition and was assigned to a hierarchical category based on the quality of the evidence from the literature supporting the recommendation and on the consensus among the experts. CONCLUSION: Despite a marked heterogeneity of scientific evidence, the method used allowed us to develop commonly agreed local guidelines for respiratory care. In addition, this work fostered a closer relationship between physiotherapists and physicians in our institution.

Analysis of acute brain slices by electron microscopy: A correlative light-electron microscopy workflow based on Tokuyasu cryo-sectioning.

Acute brain slices are slices of brain tissue that are kept vital in vitro for further recordings and analyses. This tool is of major importance in neurobiology and allows the study of brain cells such as microglia, astrocytes, neurons and their inter/intracellular communications via ion channels or transporters. In combination with light/fluorescence microscopies, acute brain slices enable the ex vivo analysis of specific cells or groups of cells inside the slice, e.g. astrocytes. To bridge ex vivo knowledge of a cell with its ultrastructure, we developed a correlative microscopy approach for acute brain slices. The workflow begins with sampling of the tissue and precise trimming of a region of interest, which contains GFP-tagged astrocytes that can be visualised by fluorescence microscopy of ultrathin sections. The astrocytes and their surroundings are then analysed by high resolution scanning transmission electron microscopy (STEM). An important aspect of this workflow is the modification of a commercial cryo-ultramicrotome to observe the fluorescent GFP signal during the trimming process. It ensured that sections contained at least one GFP astrocyte. After cryo-sectioning, a map of the GFP-expressing astrocytes is established and transferred to correlation software installed on a focused ion beam scanning electron microscope equipped with a STEM detector. Next, the areas displaying fluorescence are selected for high resolution STEM imaging. An overview area (e.g. a whole mesh of the grid) is imaged with an automated tiling and stitching process. In the final stitched image, the local organisation of the brain tissue can be surveyed or areas of interest can be magnified to observe fine details, e.g. vesicles or gold labels on specific proteins. The robustness of this workflow is contingent on the quality of sample preparation, based on Tokuyasu's protocol. This method results in a reasonable compromise between preservation of morphology and maintenance of antigenicity. Finally, an important feature of this approach is that the fluorescence of the GFP signal is preserved throughout the entire preparation process until the last step before electron microscopy.

Exposure of highway maintenance workers to fine particulate matter and noise

In this study, we assessed the mixed exposure of highway maintenance workers to airborne particles, noise, and gaseous co-pollutants. The aim was to provide a better understanding of the workers' exposure to facilitate the evaluation of short-term effects on cardiovascular health endpoints. To quantify the workers' exposure, we monitored 18 subjects during 50 non-consecutive work shifts. Exposure assessment was based on personal and work site measurements and included fine particulate matter (PM2.5), particle number concentration (PNC), noise (Leq), and the gaseous co-pollutants: carbon monoxide, nitrogen dioxide, and ozone. Mean work shift PM2.5 concentrations (gravimetric measurements) ranged from 20.3 to 321 μg m(-3) (mean 62 μg m(-3)) and PNC were between 1.6��10(4) and 4.1��10(5) particles cm(-3) (8.9��10(4) particles cm(-3)). Noise levels were generally high with Leq over work shifts from 73.3 to 96.0 dB(A); the averaged Leq over all work shifts was 87.2 dB(A). The highest exposure to fine and ultrafine particles was measured during grass mowing and lumbering when motorized brush cutters and chain saws were used. Highest noise levels, caused by pneumatic hammers, were measured during paving and guardrail repair. We found moderate Spearman correlations between PNC and PM2.5 (r = 0.56); PNC, PM2.5, and CO (r = 0.60 and r = 0.50) as well as PNC and noise (r = 0.50). Variability and correlation of parameters were influenced by work activities that included equipment causing combined air pollutant and noise emissions (e.g. brush cutters and chain saws). We conclude that highway maintenance workers are frequently exposed to elevated airborne particle and noise levels compared with the average population. This elevated exposure is a consequence of the permanent proximity to highway traffic with additional peak exposures caused by emissions of the work-related equipment.

Melanin-based coloration covaries with ovary size in an age-specific manner in the barn owl.

While the adaptive function of black eumelanin-based coloration is relatively well known, the function of reddish-brown pheomelanin-based coloration is still unclear. Only a few studies have shown or suggested that the degree of reddish-brownness is associated with predator-prey relationships, reproductive parameters, growth rate and immunity. To gain insight into the physiological correlates of melanin-based coloration, I collected barn owl (Tyto alba) cadavers and examined the covariation between this colour trait and ovary size, an organ that increases in size before reproduction. A relationship is expected because melanin-based coloration often co-varies with sexual activity. The results showed that reddish-brown juveniles had larger ovaries than whiter juveniles particularly in individuals in poor condition and outside the breeding season, while in birds older than 2 years lightly coloured females had larger ovaries than reddish-brown conspecifics. As barn owls become less reddish-brown between the first and second year of age, the present study suggests that reddish-brown pheomelanic and whitish colorations are associated with juvenile- and adult-specific adaptations, respectively.

Synchronizability of EEG-Based Functional Networks in Early Alzheimer's Disease.

Recently graph theory and complex networks have been widely used as a mean to model functionality of the brain. Among different neuroimaging techniques available for constructing the brain functional networks, electroencephalography (EEG) with its high temporal resolution is a useful instrument of the analysis of functional interdependencies between different brain regions. Alzheimer's disease (AD) is a neurodegenerative disease, which leads to substantial cognitive decline, and eventually, dementia in aged people. To achieve a deeper insight into the behavior of functional cerebral networks in AD, here we study their synchronizability in 17 newly diagnosed AD patients compared to 17 healthy control subjects at no-task, eyes-closed condition. The cross-correlation of artifact-free EEGs was used to construct brain functional networks. The extracted networks were then tested for their synchronization properties by calculating the eigenratio of the Laplacian matrix of the connection graph, i.e., the largest eigenvalue divided by the second smallest one. In AD patients, we found an increase in the eigenratio, i.e., a decrease in the synchronizability of brain networks across delta, alpha, beta, and gamma EEG frequencies within the wide range of network costs. The finding indicates the destruction of functional brain networks in early AD.

2011 Road Use Tax Fund (RUTF) Study A report to the Iowa Legislature, per 2011 Iowa Code Section 307.31

The transportation system is in demand 24/7 and 365 days a year irrespective of neither the weather nor the conditions. Iowa���s transportation system is an integral and essential part of society serving commerce and daily functions of all Iowans across the state. A high quality transportation system serves as the artery for economic activity and, the condition of the infrastructure is a key element for our future growth opportunities. A key component of Iowa���s transportation system is the public roadway system owned and maintained by the state, cities and counties. In order to regularly re-evaluate the conditions of Iowa���s public roadway infrastructure and assess the ability of existing revenues to meet the needs of the system, the Iowa Department of Transportation���s 2006 Road Use Tax Fund (RUTF) report to the legislature included a recommendation that a study be conducted every five years. That recommendation was included in legislation adopted in 2007 and signed into law. The law specifically requires the following (2011 Iowa Code Section 307.31): ������The department shall periodically review the current revenue levels of the road use tax fund and the sufficiency of those revenues for the projected construction and maintenance needs of city, county, and state governments in the future. The department shall submit a written report to the general assembly regarding its findings by December 31 every five years, beginning in 2011. The report may include recommendations concerning funding levels needed to support the future mobility and accessibility for users of Iowa's public road system.��� ������The department shall evaluate alternative funding sources for road maintenance and construction and report to the general assembly at least every five years on the advantages and disadvantages and the viability of alternative funding mechanisms.��� Consistent with this requirement, the Iowa Department of Transportation (DOT) has prepared this study. Recognizing the importance of actively engaging with the public and transportation stakeholders in any discussion of public roadway conditions and needs, Governor Terry E. Branstad announced on March 8, 2011, the creation of, and appointments to, the Governor���s Transportation 2020 Citizen Advisory Commission (CAC). The CAC was tasked with assisting the Iowa DOT as they assess the condition of Iowa���s roadway system and evaluate current and future funding available to best address system needs. In particular the CAC was directed to gather input from the public and stakeholders regarding the condition of Iowa���s public roadway system, the impact of that system, whether additional funding is needed to maintain/improve the system, and, if so, what funding mechanisms ought to be considered. With this input, the CAC prepared a report and recommendations that were presented to Governor Branstad and the Iowa DOT in November 2011 for use in the development of this study. The CAC���s report is available at www.iowadot.gov/transportation2020/pdfs/CAC%20REPORT%20FINAL%20110211.pdf. The CAC���s report was developed utilizing analysis and information from the Iowa DOT. Therefore, the report forms the basis for this study and the two documents are very similar. Iowa is fortunate to have an extensive public roadway system that provides access to all areas of the state and facilitates the efficient movement of goods and people. However, it is also a tremendous challenge for the state, cities and counties to maintain and improve this system given flattening revenue, lost buying power, changing demands on the system, severe weather, and an aging system. This challenge didn���t appear overnight and for the last decade many studies have been completed to look into the situation and the legislature has taken significant action to begin addressing the situation. In addition, the Iowa DOT and Iowa���s cities and counties have worked jointly and independently to increase efficiency and streamline operations. All of these actions have been successful and resulted in significant changes; however, it is apparent much more needs to be done. A well-maintained, high-quality transportation system reduces transportation costs and provides consistent and reliable service. These are all factors that are critical in the evaluation companies undertake when deciding where to expand or locate new developments. The CAC and Iowa DOT heard from many Iowans that additional investment in Iowa���s roadway system is vital to support existing jobs and continued job creation in the state of Iowa. Beginning June 2011, the CAC met regularly to review material and discuss potential recommendations to address Iowa���s roadway funding challenges. This effort included extensive public outreach with meetings held in seven locations across Iowa and through a Transportation 2020 website hosted by the Iowa DOT (www.iowadot.gov/transportation2020). Over 500 people attended the public meetings held through the months of August and September, with 198 providing verbal or written comment at the meetings or through the website. Comments were received from a wide array of individuals. The public comments demonstrated overwhelming support for increased funding for Iowa���s roads. Through the public input process, several guiding principles were established to guide the development of recommendations. Those guiding principles are: ��� Additional revenues are restricted for road and bridge improvements only, like 95 percent of the current state road revenue is currently. This includes the fuel tax and registration fees. ��� State and local governments continue to streamline and become more efficient, both individually and by looking for ways to do things collectively. ��� User fee concept is preserved, where those who use the roads pay for them, including non��residents. ��� Revenue-generating methods equitable across users. ��� Increase revenue generating mechanisms that are viable now but begin to implement and set the stage for longer-term solutions that bring equity and stability to road funding. ��� Continue Iowa���s long standing tradition of state roadway financing coming from pay-as-you-go financing. Iowa must not fall into the situation that other states are currently facing where the majority of their new program dollars are utilized to pay the debt service of past bonding. Based on the analysis of Iowa���s public roadway needs and revenue and the extensive work of the Governor���s Transportation 2020 Citizen Advisory Commission, the Iowa DOT has identified specific recommendations. The recommendations follow very closely the recommendations of the CAC (CAC recommendations from their report are repeated in Appendix B). Following is a summary of the recommendations which are fully documented beginning on page 21. 1. Through a combination of efficiency savings and increased revenue, a minimum of $215 million of revenue per year should be generated to meet Iowa���s critical roadway needs. 2. The Code of Iowa should be changed to require the study of the sufficiency of the state���s road funds to meet the road system���s needs every two years instead of every five years to coincide with the biennial legislative budget appropriation schedule. 3.Modify the current registration fee for electric vehicles to be based on weight and value using the same formula that applies to most passenger vehicles. 4.Consistent with existing Code of Iowa requirements, new funding should go to the TIME-21 Fund up to the cap ($225 million) and remaining new funding should be distributed consistent with the Road Use Tax Fund distribution formula. 5.The CAC recommended the Iowa DOT at least annually convene meetings with cities and counties to review the operation, maintenance and improvement of Iowa���s public roadway system to identify ways to jointly increase efficiency. In direct response to this recommendation, Governor Branstad directed the Iowa DOT to begin this effort immediately with a target of identifying $50 million of efficiency savings that can be captured from the over $1 billion of state revenue already provided to the Iowa DOT and Iowa���s cities and counties to administer, maintain and improve Iowa���s public roadway system. This would build upon past joint and individual actions that have reduced administrative costs and resulted in increased funding for improvement of Iowa���s public roadway system. Efficiency actions should be quantified, measured and reported to the public on a regular basis. 6.By June 30, 2012, Iowa DOT should complete a study of vehicles and equipment that use Iowa���s public roadway system but pay no user fees or substantially lower user fees than other vehicles and equipment.

Lenalidomide maintenance after stem-cell transplantation for multiple myeloma.

BACKGROUND: High-dose chemotherapy with autologous stem-cell transplantation is a standard treatment for young patients with multiple myeloma. Residual disease is almost always present after transplantation and is responsible for relapse. This phase 3, placebo-controlled trial investigated the efficacy of lenalidomide maintenance therapy after transplantation. METHODS: We randomly assigned 614 patients younger than 65 years of age who had nonprogressive disease after first-line transplantation to maintenance treatment with either lenalidomide (10 mg per day for the first 3 months, increased to 15 mg if tolerated) or placebo until relapse. The primary end point was progression-free survival. RESULTS: Lenalidomide maintenance therapy improved median progression-free survival (41 months, vs. 23 months with placebo; hazard ratio, 0.50; P<0.001). This benefit was observed across all patient subgroups, including those based on the &#946;(2)-microglobulin level, cytogenetic profile, and response after transplantation. With a median follow-up period of 45 months, more than 70% of patients in both groups were alive at 4 years. The rates of grade 3 or 4 peripheral neuropathy were similar in the two groups. The incidence of second primary cancers was 3.1 per 100 patient-years in the lenalidomide group versus 1.2 per 100 patient-years in the placebo group (P=0.002). Median event-free survival (with events that included second primary cancers) was significantly improved with lenalidomide (40 months, vs. 23 months with placebo; P<0.001). CONCLUSIONS: Lenalidomide maintenance after transplantation significantly prolonged progression-free and event-free survival among patients with multiple myeloma. Four years after randomization, overall survival was similar in the two study groups. (Funded by the Programme Hospitalier de Recherche Clinique and others; ClinicalTrials.gov number, NCT00430365.).

Holt Oram syndrome: a registry-based study in Europe.

BACKGROUND: Holt-Oram syndrome (HOS) is an autosomal dominant disorder characterised by upper limb anomalies and congenital heart defects. We present epidemiological and clinical aspects of HOS patients using data from EUROCAT (European Surveillance of Congenital Anomalies) registries. METHODS: The study was based on data collected during 1990-2011 by 34 registries. The registries are population-based and use multiple sources of information to collect data on all types of birth using standardized definitions, methodology and coding. Diagnostic criteria for inclusion in the study were the presence of radial ray abnormalities and congenital heart disease (CHD), or the presence of either radial ray anomaly or CHD, with family history of HOS. RESULTS: A total of 73 cases of HOS were identified, including 11 (15.1%) TOPFA and 62 (84.9%) LB. Out of 73 HOS cases, 30.8% (20/65) were suspected prenatally, 55.4% (36/65) at birth, 10.7% (7/65) in the first week of life, and 3.1% (2/65) in the first year of life. The prenatal detection rate was 39.2% (20/51), with no significant change over the study period. In 55% (11/20) of prenatally detected cases, parents decided to terminate pregnancy. Thumb anomalies were reported in all cases. Agenesis/hypoplasia of radius was present in 49.2% (30/61), ulnar aplasia/hypoplasia in 24.6% (15/61) and humerus hypoplasia/phocomelia in 42.6% (26/61) of patients. Congenital heart defects (CHD) were recorded in 78.7% (48/61) of patients. Isolated septal defects were present in 54.2 (26/48), while 25% (12/48) of patients had complex/severe CHD. The mean prevalence of HOS diagnosed prenatally or in the early years of life in European registries was 0.7 per 100,000 births or 1:135,615 births. CONCLUSIONS: HOS is a rare genetic condition showing regional variation in its prevalence. It is often missed prenatally, in spite of the existence of major structural anomalies. When discovered, parents in 45% (9/20) of cases opt for the continuation of pregnancy. Although a quarter of patients have severe CHD, the overall first week survival is very good, which is important information for counselling purposes.

Highway Maintenance Concept Vehicle, June 2002

This report documents Phase IV of the Highway Maintenance Concept Vehicle (HMCV) project, a pooled fund study sponsored by the Departments of Transportation of Iowa, Pennsylvania, and Wisconsin. This report provides the background, including a brief history of the earlier phases of the project, a systems overview, and descriptions of the research conducted in Phase IV. Finally, the report provides conclusions and recommendations for future research. Background The goal of the Highway Maintenance Concept Vehicle Pooled Fund Study is to provide travelers with the level of service defined by policy during the winter season at the least cost to taxpayers. This goal is to be accomplished by using information regarding actual road conditions to facilitate and adjust snow and ice control activities. The approach used in this study was to bring technology applications from other industries to the highway maintenance vehicle. This approach is evolutionary in that as emerging technologies and applications are found to be acceptable to the pooled fund states and as they appear that to have potential for supporting the study goals they become candidates for our research. The objective of Phase IV is to: Conduct limited deployment of selected technologies from Phase III by equipping a vehicle with proven advanced technologies and creating a mobile test laboratory for collecting road weather data. The research quickly pointed out that investments in winter storm maintenance assets must be based on benefit/cost analysis and related to improving level of service. For example, Iowa has estimated the average cost of fighting a winter storm to be about $60,000 to $70,000 per hour typically. The maintenance concept vehicle will have advanced technology equipment capable of applying precisely the correct amount of material, accurately tailored to the existing and predicted pavement conditions. Hence, a state using advanced technology could expect to have a noticeable impact on the average time taken to establish the winter driving service level. If the concept vehicle and data produced by the vehicle are used to support decision-making leading to reducing material usage and the average time by one hour, a reasonable benefit/cost will result. Data from the friction meter can be used to monitor and adjust snow and ice control activities and inform travelers of pavement surface conditions. Therefore, final selection of successfully performing technologies will be based on the foundation statements and criteria developed by the study team.

Mechanisms involved in the maintenance of inbreeding depression in gynodioecious "Silene vulgaris" (Caryophyllaceae): an experimental investigation

Summary Gynodioecy, the joint occurrence of females and hermaphrodites within natural populations, is a widely studied mating system ever since Darwin (1877). It is an exceptional mating system because continuous selection is necessary to maintain it. Since females only reproduce through ovules whereas hermaphrodites transmit genes through ovules and pollen, larger female fitness, in terms of seed output, is required to allow their maintenance. Two non-exclusive mechanisms can account for the maintenance of females. First, as females do not produce pollen they can reallocate their resources towards a higher ovule production. Second, hermaphrodites can self- and cross-fertilize whereas females are obligate outcrossers. Thus hermaphrodites should partly suffer from inbreeding depression (i.e.: the fitness decline of inbred relative to outbred individuals) and thereby produce less fit progeny than females. This thesis investigated the effects of self- and cross-fertilization of heimaphrodites over two consecutive generations. Inbreeding depression increased across the successive stages of the life- cycle (i.e.: from "seed traits" to "reproductive traits") displaying large inbreeding depression estimates (up to 0.76). This investigation not only detected large inbreeding depression estimates but also detected mechanisms involved in the maintenance of inbreeding depression. For instance cryptic self-incompatibility which is here a larger in vivo pollen performance of distant pollen compared to self-pollen; the expression of inbreeding depression especially in late life-cycle stages, and the appearance of females in the progeny of selfed hermaphrodites. The female biased sex ratio in the progeny of selfed hermaphrodites was a surprising result and could either come from the sex determining mechanisms (complex nucleo-cytoplasmic interaction(s)) and/or from inbreeding depression. Indeed, we not only got females and hermaphrodites but also partial male-sterile (PMS) individuals (i.e.: individuals with differing number of viable stamens). We detected that inbred pollen bearing plants (excluding females) have less viable stamens per flower than outbred plants. A positive correlation was detected between inbreeding depression for the number of viable stamens per flower and the difference in sex ratio between inbred and outbred individuals. A positive relationship was also detected between inbreeding depression for pollen viability and inbreeding depression for number of viable stamens per flower. Each correlation can either account for pleiotropic effects (a major gene acting on the two considered traits) or linkage disequilibrium between genes controlling each of the two related traits. If we hypothesize that these correlations are due to a major gene with pleiotropic effects, the positive relationship between inbreeding depression for number of viable stamens per flower and inbreeding depression for pollen viability showed that deleterious alleles present on a major gene coding for pollen production and viability depressed male fitness within inbred plants. The positive relationship between sex ratio difference between inbred and outbred individuals and inbreeding depression for number of viable stamens per flower indicates that (1) either number of viable stamens per flower is, in addition to inbreeding, also affected by the loci coding for sex determinism or, (2) the presence of females within the progeny of selfed hermaphrodites is a consequence of large inbreeding depression inhibiting pollen production, or (3) sex is here determined by a combination of loci coding for sex expression and inbreeding depression for male reproductive traits. In conclusion, Silene vulgaris has been shown to be a good model for understanding the evolution of mating systems that promote outbreeding. R��sum�� La gynod��o��cie est d��finie comme ��tant la pr��sence simultan��e d'hermaphrodites et de femelles au sein de populations naturelles d'une m��me esp��ce. Ce syst��me de reproduction a toujours fascin�� le monde scientifique depuis Darwin, comme en t��moigne ses ��crits (1876, 1877) sur les syst��mes de reproduction chez les plantes. Les femelles ne transmettent leurs g��nes qu'�� travers leurs ovules alors que les hermaphrodites transmettent leurs g��nes �� la fois par la voie m��le (le pollen) et la voie femelle (les ovules). La condition pour que la gynod��o��cie se maintienne n��cessite donc une fitness de la fonction femelle plus ��lev��e chez les femelles que chez les hermaphrodites. Deux m��canismes mutuellement non exclusifs peuvent expliquer le maintien des femelles au sein de ces populations gynodio��ques. D'une part, les femelles peuvent r��allouer les ressources non utilis��es pour la production de pollen et peuvent par cons��quent produire plus d'ovules. D'autre part, la reproduction des femelles ne peut se faire que par allo-f��condation alors que les hermaphrodites, peuvent se reproduire �� la fois par auto- et allo-f��condation. L'autof��condation s'accompagne en g��n��ral d'une diminution de fitness de la descendance relativement �� la prog��niture issue d'allo-f��condation ; ce ph��nom��ne est connu sous le nom de d��pression de consanguinit��. Cette th��se avait pour but de mettre en ��vidence une ��ventuelle d��pression de consanguinit�� chez Silene vulgaris, une esp��ce gynodio��que. Des hermaphrodites, issus de trois vall��es alpines, ont ��t�� auto- et allo��f��cond��s sur deux g��n��rations successives. La d��pression de consanguinit�� pouvant s'exprimer �� tous les stades de vie d'un individu, plusieurs traits de fitness, allant du nombre de graines par fruit �� la production de gam��tes ont ��t�� mesur��s sur diff��rents stades de vie successifs. L'estimation de la d��pression de consanguinit�� totale atteignait des valeurs allant de 0.52 �� 0.76 selon la vall��e consid��r��e, ce qui indiquerait que les hermaphrodites ont tout int��r��t �� limiter l'autof��condation et que les femelles ne devraient pas avoir de peine �� subsister dans les vall��es ��tudi��es. Par la m��me occasion des m��canismes diminuant la purge potentielle du fardeau g��n��tique, et permettant ainsi le maintien du �� niveau �� de d��pression de consanguinit�� et par cons��quence le maintien de la gynod��o��cie ont ��t�� mis en ��vidence. En effet, nos r��sultats montrent que la d��pression de consanguinit�� s'exprimait tard dans le cycle de vie permettant ainsi �� un certain nombre individus consanguins de transmettre leurs all��les d��l��t��res �� la g��n��ration suivante. D'autre part, la croissance in vivo des tubes polliniques d'auto-pollen ��tait plus lente que celle de l'allo-pollen et donc en situation de comp��tition directe, les ovules devraient plut��t ��tre issus d'allo-f��condation, diminuant ainsi les chances de purges d'all��les d��l��t��res. Enfin, l'apparition de femelles dans la prog��niture d'hermaphrodites autof��cond��s diminue aussi les chances de purge d'all��les d��l��t��res. Il nous a ��t�� impossible de d��terminer si l'apparition de femelles dans la descendance d'hermaphrodites autof��cond��s ��tait due au d��terminisme g��n��tique du sexe ou si la diff��rence de sexe ratio entre la descendance auto- et allo-f��cond��e ��tait due �� une ��ventuelle d��pression de consanguinit�� inhibant la production de pollen. Nous avons observ�� que S. vulgaris ne pr��sentaient pas uniquement des hermaphrodites et des femelles mais aussi toute sorte d'individus interm��diaires avec un nombre variable d'��tamines viables. Nous avons pu mettre' en ��vidence des corr��lations positives entre (1) la diff��rence de sexe ratio (la proportion d'individus produisant du pollen) entre individus consanguins et non consanguins et une estimation de la d��pression de consanguinit�� pour le nombre d'��tamines viables d'individus produisant du pollen, ainsi qu'entre (2) la d��pression de consanguinit�� pour le nombre d'��tamines viables et celle estim��e pour la viabilit�� du pollen. Chaque corr��lation indique soit l'effet d'un (ou plusieurs) g��ne(s) pl��iotropique(s), soit un d��s��quilibre de liaison entre les g��nes. En consid��rant que ces corr��lations sont le r��sultat d'effet pl��iotropiques, la relation entre le nombre d'��tamines viables par fleur et la viabilit�� du pollen, indiquerait un effet n��gatif de la consanguinit�� sur la production et la viabilit�� du pollen due partiellement �� un g��ne majeur. La seconde corr��lation indiquerait soit que les g��nes responsables de la d��termination du sexe agissent aussi sur l'expression de la fonction m��le soit que l'expression du sexe est sujette �� la d��pression de consanguinit��, ou encore un m��lange des deux. Aux regards de ces r��sultats, Silene vulgaris s'est av��r�� ��tre un bon mod��le de compr��hension de l'��volution des syst��mes de reproduction vers la s��paration des sexes.

Performance Evaluation Of Iowa Bridge Decks Constructed With Epoxy-Coated Reinforcing Bars, RB06-011, 2011

Epoxy coatings have been used on the embedded reinforcing bars of bridge decks since the mid-1970s to mitigate deterioration caused by chloride-induced corrosion. The use of chloride-based deicers became common in the early 1960s and caused corrosion of conventional uncoated bars in bridge decks within 5 to 10 years of commencement of deicer applications. In response to this rapid deterioration, the National Bureau of Standards researched coatings to protect the reinforcement (National Bureau of Standards, 1975), resulting in the development of epoxy-coated reinforcing bars, which were used in bridge decks beginning in 1973. While corrosion-related deterioration has been prevalent on bridge decks with uncoated reinforcing bars in northern climates where the use of deicing salts is common, bridge decks constructed after 1973 with epoxy-coated reinforcing have shown good corrosion resistance with only limited exceptions. On the whole, previous laboratory and field studies regarding the performance of epoxy-coated reinforcing bars are very promising; however, some laboratory and field studies have yielded differing results. In recent years, maintenance personnel for the Iowa Department of Transportation (Iowa DOT) have reportedly performed patch repairs to some bridge decks reinforced with epoxy-coated bars. At one such bridge, the southbound US 65 bridge (Bridge No. 7788.5L065) over the Union Pacific Railroad near Bondurant in Polk County, Iowa, deck repairs were performed by Iowa DOT maintenance personnel in the Spring of 2010, based on our communications regarding this topic with Mr. Gordon Port of the Iowa DOT. These repairs were observed by engineers from the Iowa DOT Office of Bridges and Structures, who reported that significant corrosion was found at a number of epoxy-coated reinforcing bars uncovered during this patch work. These repairs were reportedly performed at spalls and delaminated areas corresponding to cracks over transverse reinforcing bars, and involved careful removal of the concrete from over the bars. Figures 1 through 4 contain photographs provided by Iowa DOT personnel showing the removal process (Figure 1), the conditions encountered (Figures 2 and 3), and close-up views of the corroded reinforcing (Figure 4). As a result of these observations, the Iowa Department of Transportation has requested this study to gain further understanding of the long-term performance of bridge decks reinforced with epoxy-coated bars. The two main objectives of this study are to determine the long-term effectiveness of the epoxy coatings and to determine the potential causes for the deterioration at locations where corrosion has occurred. Wiss, Janney, Elstner Associates, Inc. (WJE) and the Iowa DOT identified eight different bridge decks across Iowa for this study that were constructed using epoxy-coated reinforcing bars. A field investigation consisting of visual inspections, a delamination survey, a concrete cover survey, electrical testing for susceptibility to corrosion, and concrete sampling was conducted within a survey area deemed to be representative of the condition of each bridge deck. Laboratory testing, including chloride ion content testing, characterization of the extracted bars, petrographic examination of the concrete, and carbonation testing, was conducted on the core samples taken from each bridge deck.

Assessment of Weathering Steel Bridge Performance in Iowa and Development of Inspection and Maintenance Techniques, RB17-012, 2013

Weathering steel is commonly used as a cost-effective alternative for bridge superstructures, as the costs and environmental impacts associated with the maintenance/replacement of paint coatings are theoretically eliminated. The performance of weathering steel depends on the proper formation of a surface patina, which consists of a dense layer of corrosion product used to protect the steel from further atmospheric corrosion. The development of the weathering steel patina may be hindered by environmental factors such as humid environments, wetting/drying cycles, sheltering, exposure to de-icing chlorides, and design details that permit water to pond on steel surfaces. Weathering steel bridges constructed over or adjacent to other roadways could be subjected to sufficient salt spray that would impede the development of an adequate patina. Addressing areas of corrosion on a weathering steel bridge superstructure where a protective patina has not formed is often costly and negates the anticipated cost savings for this type of steel superstructure. Early detection of weathering steel corrosion is important to extending the service life of the bridge structure; however, written inspection procedures are not available for inspectors to evaluate the performance or quality of the patina. This project focused on the evaluation of weathering steel bridge structures, including possible methods to assess the quality of the weathering steel patina and to properly maintain the quality of the patina. The objectives of this project are summarized as follows: ��� Identify weathering steel bridge structures that would be most vulnerable to chloride contamination, based on location, exposure, environment, and other factors. ��� Identify locations on an individual weathering steel bridge structure that would be most susceptible to chloride contamination, such as below joints, splash/spray zones, and areas of ponding water or debris. ��� Identify possible testing methods and/or inspection techniques for inspectors to evaluate the quality of the weathering steel patina at locations discussed above. ��� Identify possible methods to measure and evaluate the level of chloride contamination at the locations discussed above. ��� Evaluate the effectiveness of water washing on removing chlorides from the weathering steel patina. ��� Develop a general prioritization for the washing of bridge structures based on the structure���s location, environment, inspection observations, patina evaluation findings, and chloride test results.

Development of a GPS-Based Sign Inventory Tool for Iowa���s Statewide Management System, May 2011

This report is on state-of-the-art research efforts specific to infrastructure inventory/data collection with sign inventory as a case study. The development of an agency-wide sign inventory is based on feature inventory and location information. Specific to location, a quick and simple location acquisition tool is critical to tying assets to an accurate location-referencing system. This research effort provides a contrast between legacy referencing systems (route and milepost) and global positioning system- (GPS-) based techniques (latitude and longitude) integrated into a geographic information system (GIS) database. A summary comparison of field accuracies using a variety of consumer grade devices is also provided. This research, and the data collection tools developed, are critical in supporting the Iowa Department of Transportation (DOT) Statewide Sign Management System development effort. For the last two years, a Task Force has embarked on a comprehensive effort to develop a sign management system to improve sign quality, as well as to manage all aspects of signage, from request, ordering, fabricating, installing, maintaining, and ultimately removing, and to provide the ability to budget for these key assets on a statewide basis. This effort supported the development of a sign inventory tool and is the beginning of the development of a sign management system to support the Iowa DOT efforts in the consistent, cost effective, and objective decision making process when it comes to signs and their maintenance.