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. Résumé La gynodïoécie est définie comme étant la présence simultanée d'hermaphrodites et de femelles au sein de populations naturelles d'une même espèce. Ce système de reproduction a toujours fasciné le monde scientifique depuis Darwin, comme en témoigne ses écrits (1876, 1877) sur les systèmes de reproduction chez les plantes. Les femelles ne transmettent leurs gènes qu'à travers leurs ovules alors que les hermaphrodites transmettent leurs gènes à la fois par la voie mâle (le pollen) et la voie femelle (les ovules). La condition pour que la gynodïoécie se maintienne nécessite donc une fitness de la fonction femelle plus élevée chez les femelles que chez les hermaphrodites. Deux mécanismes mutuellement non exclusifs peuvent expliquer le maintien des femelles au sein de ces populations gynodioïques. D'une part, les femelles peuvent réallouer les ressources non utilisées pour la production de pollen et peuvent par conséquent produire plus d'ovules. D'autre part, la reproduction des femelles ne peut se faire que par allo-fécondation alors que les hermaphrodites, peuvent se reproduire à la fois par auto- et allo-fécondation. L'autofécondation s'accompagne en général d'une diminution de fitness de la descendance relativement à la progéniture issue d'allo-fécondation ; ce phénomène est connu sous le nom de dépression de consanguinité. Cette thèse avait pour but de mettre en évidence une éventuelle dépression de consanguinité chez Silene vulgaris, une espèce gynodioïque. Des hermaphrodites, issus de trois vallées alpines, ont été auto- et allo¬fécondés sur deux générations successives. La dépression de consanguinité pouvant s'exprimer à tous les stades de vie d'un individu, plusieurs traits de fitness, allant du nombre de graines par fruit à la production de gamètes ont été mesurés sur différents stades de vie successifs. L'estimation de la dépression de consanguinité totale atteignait des valeurs allant de 0.52 à 0.76 selon la vallée considérée, ce qui indiquerait que les hermaphrodites ont tout intérêt à limiter l'autofécondation et que les femelles ne devraient pas avoir de peine à subsister dans les vallées étudiées. Par la même occasion des mécanismes diminuant la purge potentielle du fardeau génétique, et permettant ainsi le maintien du « niveau » de dépression de consanguinité et par conséquence le maintien de la gynodïoécie ont été mis en évidence. En effet, nos résultats montrent que la dépression de consanguinité s'exprimait tard dans le cycle de vie permettant ainsi à un certain nombre individus consanguins de transmettre leurs allèles délétères à la génération suivante. D'autre part, la croissance in vivo des tubes polliniques d'auto-pollen était plus lente que celle de l'allo-pollen et donc en situation de compétition directe, les ovules devraient plutôt être issus d'allo-fécondation, diminuant ainsi les chances de purges d'allèles délétères. Enfin, l'apparition de femelles dans la progéniture d'hermaphrodites autofécondés diminue aussi les chances de purge d'allèles délétères. Il nous a été impossible de déterminer si l'apparition de femelles dans la descendance d'hermaphrodites autofécondés était due au déterminisme génétique du sexe ou si la différence de sexe ratio entre la descendance auto- et allo-fécondée était due à une éventuelle dépression de consanguinité inhibant la production de pollen. Nous avons observé que S. vulgaris ne présentaient pas uniquement des hermaphrodites et des femelles mais aussi toute sorte d'individus intermédiaires avec un nombre variable d'étamines viables. Nous avons pu mettre' en évidence des corrélations positives entre (1) la différence de sexe ratio (la proportion d'individus produisant du pollen) entre individus consanguins et non consanguins et une estimation de la dépression de consanguinité pour le nombre d'étamines viables d'individus produisant du pollen, ainsi qu'entre (2) la dépression de consanguinité pour le nombre d'étamines viables et celle estimée pour la viabilité du pollen. Chaque corrélation indique soit l'effet d'un (ou plusieurs) gène(s) pléiotropique(s), soit un déséquilibre de liaison entre les gènes. En considérant que ces corrélations sont le résultat d'effet pléiotropiques, la relation entre le nombre d'étamines viables par fleur et la viabilité du pollen, indiquerait un effet négatif de la consanguinité sur la production et la viabilité du pollen due partiellement à un gène majeur. La seconde corrélation indiquerait soit que les gènes responsables de la détermination du sexe agissent aussi sur l'expression de la fonction mâle soit que l'expression du sexe est sujette à la dépression de consanguinité, ou encore un mélange des deux. Aux regards de ces résultats, Silene vulgaris s'est avéré être un bon modèle de compréhension de l'évolution des systèmes de reproduction vers la séparation des sexes.

Iowa Highway Research Board FY 2012 Annual Report

This report, entitled ―Iowa Highway Research Board Research and Development Activities FY2012‖ is submitted in compliance with Sections 310.36 and 312.3A, Code of Iowa, which direct the submission of a report of the Secondary Road Research Fund and the Street Research Fund, respectively. It is a report of the status of research and development projects in progress on June 30, 2012. It is also a report on projects completed during the fiscal year beginning July 1, 2011 and ending June 30, 2012. Detailed information on each of the research and development projects mentioned in this report is available from the Office of Research and Analytics, Performance and Technology Division, Iowa Department of Transportation. All approved reports are also online for viewing at: www.iowadot.gov/operationsresearch/reports.aspx.

FY2012 Highway Construction Program Expenditures/Obligations

This report describes the highway construction program, actual expenditures of the program and contractual obligations of the program for FY 2012.

Predicting the need for ditch network maintenance in drained peatland sites in Finland

Kunnostusojitustarpeen ennustaminen ojitusalueilla

Effect of drainage maintenance on the nutrient status on drained Scots pine mires

Tiivistelmä: Kunnostusojituksen vaikutus rämeiden ravinnetilaan

Radioimmunotherapy combined with maintenance anti-CD20 antibody may trigger long-term protective T cell immunity in follicular lymphoma patients.

Growing evidence suggests that the patient's immune response may play a major role in the long-term efficacy of antibody therapies of follicular lymphoma (FL). Particular long-lasting recurrence free survivals have been observed after first line, single agent rituximab or after radioimmunotherapy (RIT). Rituximab maintenance, furthermore, has a major efficacy in prolonging recurrence free survival after chemotherapy. On the other hand, RIT as a single step treatment showed a remarkable capacity to induce complete and partial remissions when applied in recurrence and as initial treatment of FL or given for consolidation. These clinical results strongly suggest that RIT combined with rituximab maintenance could stabilize the high percentages of patients with CR and PR induced by RIT. While the precise mechanisms of the long-term efficacy of these 2 treatments are not elucidated, different observations suggest that the patient's T cell immune response could be decisive. With this review, we discuss the potential role of the patient's immune system under rituximab and RIT and argue that the T cell immunity might be particularly promoted when combining the 2 antibody treatments in the early therapy of FL.

Roadway Alignments as Assets: Evaluating Alternatives for Valuing Major Highway Corridor Rights of Way Final Report December 2010 Sponsored

In most highway asset management exercises, real estate used in alignments is considered to be an asset class that does not depreciate. Although the treatment of right of way assets as non-depreciable real property may be appropriate as an accounting exercise, the fact is that the real estate contained in transportation corridors can in fact lose value from a traffic service point of view. Such facilities become functionally obsolete in that they no longer serve the purpose that was intended when they were planned, designed, and built. This report is intended to begin a discussion of the topic of how highway alignments ought be valued as assets as opposed to how they generally are valued, at either book value or replacement value, given it can be shown that some highway alignments do in fact depreciate in value.

General highway and transportation map,1978.

Contains a highway map of each county in Iowa

Maintenance Asset Management Project -- Phase II, July 31, 2013

Expanded abstract: Iowa Department of Transportation (IA DOT) is finalizing research to streamline field inventory/inspection of culverts by Maintenance and Construction staff while maximizing the use of tablet technologies. The project began in 2011 to develop some new best practices for field staff to assist in the inventory, inspection and maintenance of assets along the roadway. The team has spent the past year working through the complexities of identifying the most appropriate tablet hardware for field data collection. A small scale deployment of tablets occurred in spring of 2013 to collect several safety related assets (culverts, signs, guardrail, and incidents). Data can be collected in disconnected or connected modes and there is an associated desktop environment where data can be viewed and queried after being synced into the master database. The development of a deployment plan and related workflow processes are underway; which will eventually feed information into IA DOTs larger asset management system and make the information available for decision making. The team is also working with the IA DOT Design Office on Computer Aided Drafting (CAD) data processing and the IA DOT Construction office with a new digital As-Built plan process to leverage the complete data life-cycle so information can be developed once and leveraged by the Maintenance staff farther along in the process.

Feasibility Study for Detection and Quantification of Corrosion in Bridge Barrier Rails, RB11-012, 2013

"Technical challenges exist with infrastructure that can be addressed by nondestructive evaluation (NDE) methods, such as detecting corrosion damage to reinforcing steel that anchor concrete bridge railings to bridge road decks. Moisture and chloride ions reach the anchors along the cold joint between the rails and deck, causing corrosion that weakens the anchors and ultimately the barriers. The Center for Nondestructive Evaluation at Iowa State University has experience in development of measurement techniques and new sensors using a variety of interrogating energies. This research evaluated feasibility of three technologies — x-ray radiation, ground-penetrating radar (GPR), and magnetic flux leakage (MFL) — for detection and quantification of corrosion of embedded reinforcing steel. Controlled samples containing pristine reinforcing steel with and without epoxy and reinforcing steel with 25 percent and 50 percent section reduction were embedded in concrete at 2.5 in. deep for laboratory evaluation. Two of the techniques, GPR and MFL, were used in a limited field test on the Iowa Highway 210 Bridge over Interstate 35 in Story County. The methods provide useful and complementary information. GPR provides a rapid approach to identify reinforcing steel that has anomalous responses. MFL provides similar detection responses but could be optimized to provide more quantitative correlation to actual condition. Full implementation could use either GPR or MFL methods to identify areas of concern, followed by radiography to give a visual image of the actual condition, providing the final guidance for maintenance actions." The full 103 page report and the 2 page Tech Transfer Summary are included in this link.

Concrete Pavement Mixture Design and Analysis (MDA) Guide Specification for Highway Concrete Pavements: Commentary, TPF-5(205), 2012

This guide specification and commentary for concrete pavements presents current state-of-the art thinking with respect to materials and mixture selection, proportioning, and acceptance. This document takes into account the different environments, practices, and materials in use across the United States and allows optional inputs for local application. The following concrete pavement types are considered: jointed plain concrete pavement, the most commonly used pavement type and may be doweled or non-doweled at transverse joints; and continuously reinforced concrete pavement, typically constructed without any transverse joints, typically used for locations with high truck traffic loads and/or poor support conditions.

Concrete Pavement Mixture Design and Analysis (MDA) Guide Specification for Highway Concrete Pavements, TPF-5(205), 2012

A guide specification and commentary have been prepared that lay out current state-of-the art thinking with respect to materials and mixture selection, proportioning, and acceptance. These documents take into account the different environments, practices, and materials in use across the US and allow optional inputs for local application.

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.

Laboratory and Field Testing of an Accelerated Bridge Construction Demonstration Bridge: US Highway 6 Bridge over Keg Creek, RB02-012, 2013

The US Highway 6 Bridge over Keg Creek outside of Council Bluffs, Iowa is a demonstration bridge site chosen to put into practice newly-developed Accelerated Bridge Construction (ABC) concepts. One of these new concepts is the use of prefabricated high performance concrete (HPC) bridge elements that are connected, in place, utilizing advanced material closure-pours and quick-to-install connection details. The Keg Creek Bridge is the first bridge in the US to utilize moment-resisting ultra-high performance concrete (UHPC) joints in negative moment regions over piers. Through laboratory and live load field testing, performance of these transverse joints as well as global bridge behavior is quantified and examined. The effectiveness of the structural performance of the bridge is evaluated to provide guidance for future designs of similar bridges throughout the US.