Core reference sets of sorghum and musa : from a whole collection to a mini core collection and back (W291)

The core approach for investigating genetic diversity in a crop germplasm collection has proven merits, among which the possibility to choose a sample of manageable size (e.g. a 'minicore'), so that it can be studied in details, be exchanged among researchers and users and serve as a common reference for integration of data of multiple sources. In turn, studies on a mini core collection can help direct further investigation in the whole collection and target specific compartments for specific purposes. The Generation Challenge Programme is helping various germplasm centers develop genetic stocks to serve as core reference sets for an array of important food crops ; the case of sorghum will be presented as an advanced example. Sorghum reference set has been evaluated under normal and postflowering water stress conditions at ICRISAT. A wide range of variation for agronomic traits, including yield and Fe and Zn have been observed and promising lines selected for use in breeding programmes. The forthcoming possibility to apply massive genotyping to crop germplasm may justify adaptation of scientific strategies, in relation to the biology and the history of the crops. These aspects will be discussed for two contrasting crops, namely sorghum, a diploid, predominantly inbreeding cereal crop with vast germplasm collections, and banana/plantain, a multi-, essentially tri-ploid, vegetatively propagated fruit crop with collections of limited size. (Texte intégral

Access to Core Course Materials Project: Teaching Collection Experiment report

This report documents the third phase in the Access to Core Course Material project, known as the Teaching Collection Experiment. The work began in March 2001 and was completed in September 2001. The Teaching Collection is the name given to the printed reserve at UCL. It contains off-prints of essential course readings that are kept behind issue desks at both the Main and Science Library. Lecturers can place up to five copies of materials in the Collection, which are entered onto the library catalogue and given an unique identifying number. The Experiment investigated the feasibility of digitising a selection of this material and making it available electronically. This report documents the production process and compares the costs and quality of an in-house service with out-sourcing production. This allowed the project team to investigate the feasibility of offering a clearance and/or digitisation service in-house and the costs associated with such activities. The experiment also examined how this service related to the current activities of the Library and might be integrated into existing services. Following on from this experiment, a pilot service known as DigiCOMS was offered to a further 5 departments at UCL. The digitised material produced during the Teaching Collection Experiment was therefore made available through the DigiCOMS service. More details about DigiCOMS are available in a separate report. The Economics Department was selected to participate in this experiment, as they currently use the Teaching Collection to deposit a considerable number of course readings. Using a department from the social sciences also compliments the earlier work for the Dutch Department. It was also important to choose a department whose reading lists contained considerable numbers of published journal articles and chapters from books that required copyright permission from publishers. A selection of material that the department currently deposit in the Teaching Collection was identified, in addition to some material which students had found problematic to get hold of in the past. It should be pointed out at this stage that the distinction between a printed study pack and a teaching collection item in a print environment is significant, in particular for legal reasons, because a set of readings cannot placed within the teaching collection to avoid the copyright costs associated with producing a study pack. However, this distinction is less clear cut once material is made available electronically. Therefore, although the material in the teaching collection did not form a printed study pack, the set of digitised readings are referred to as an electronic study pack. Electronic permissions are also granted by publishers along similar lines to printed study packs, in that the pricing model is based on the length of a particular extract and the number of students on the course

Bacterial wilt resistance in tomato, eggplant and pepper : genetic resources challenged with the multifaceted Ralstonia solanacearum species complex : [P3-49]

Bacterial wilt caused by strains belonging to the #Ralstonia solanacearum# species complex inflicts severe economic losses in many crops worldwide. Host resistance remains the most effective control strategy against the bacterial wilt. However, interactions among plant, strain and environment often result in overcoming resistance properties due to variation in strain pathogenicity and adaptation. To help breeders circumvent this problem, we assembled a worldwide collection of 30 accessions of Tomato, Eggplant and Pepper (Core-TEP) that are commonly used as sources of resistance to #R. solanacearum# or for mapping QTLs. The Core-TEP lines were challenged with a core collection of 12 pathogen strains (Core-Rs2) representing the phylogenetic diversity of #R. solanacearum#. To our knowledge, this is the first study that investigated bacterial wilt resistance in a set of worldwide genetic resources used as sources of resistance in three solanaceous species (tomato, eggplant, and pepper). Our results showed that none of the Core-TEP accessions, representative of the TEP genetic diversity for resistance, was resistant to all Core-Rs2 strains. Hence, none of them displayed universal resistance. We observed six wilt interaction phenotypes, from highly susceptible to highly resistant. Intermediate phenotype resulted from the ability of plants to tolerate latent infections, i.e. bacterial colonization of vascular elements with limited or no wilting. #R. solanacearum# strains exhibited specific patterns of interaction with Core-TEP accessions. Thanks to several similarities of virulence patterns between strains of Core-Rs2, we defined two working concepts associated with two levels of resolution of the interactions between strains and plant phenotypes. One concept, the "pathoprofile" is based on the interactions for the three solanaceae taken together, and the other, the pathotype is based on the interactions for each plant species taken separately. The 12 Core-Rs2 strains partitioned into four pathotypes on Pepper accessions, five pathotypes on Tomato, six pathotypes on Eggplant, and six pathoprofiles on the whole set of Core-TEP accessions. Neither pathotypes nor pathoprofiles were phylotype-specific. Pathoprofiles with high pathogenicity were mainly found in strains from phylotypes I, IIB and III. One pathoprofile included a strain that overcame almost all resistance sources. (Résumé d'auteur

Garbage collection auto-tuning for Java MapReduce on Multi-Cores

MapReduce has been widely accepted as a simple programming pattern that can form the basis for efficient, large-scale, distributed data processing. The success of the MapReduce pattern has led to a variety of implementations for different computational scenarios. In this paper we present MRJ, a MapReduce Java framework for multi-core architectures. We evaluate its scalability on a four-core, hyperthreaded Intel Core i7 processor, using a set of standard MapReduce benchmarks. We investigate the significant impact that Java runtime garbage collection has on the performance and scalability of MRJ. We propose the use of memory management auto-tuning techniques based on machine learning. With our auto-tuning approach, we are able to achieve MRJ performance within 10% of optimal on 75% of our benchmark tests

Becoming the Gothic Archive: From Digital Collection to Digital Humanities

The Gothic Archive is the flagship digital humanities project for the Marquette University library. The project was birthed from a simple digital collection, and through the partnership of faculty and librarians, was transformed into something more. The core tenets of digital collection creation were adhered to in order to create a solid foundation upon which to build the Archive. The expertise of both groups and communication were key in the evolution of the collection, and in discovering and highlighting the relationships between the objects. This case study reviews the steps Marquette took in creating the collection and taking it to the level of digital humanities project

COMPARATIVE STATICS AND LAWS OF SCARCITY FOR GAMES

A 2law of scarcity2 is that scarceness is rewarded. We demonstrate laws of scarcity for cores and approximate cores of games. Furthermore, we demonstrate conditions under which all payoffs in the core of any game in a parametized collection have an equal treatment property and show that equal treatment core payoff vectors satisfy a condition of cyclic monotonicity. Our results are developed for parameterized collections of games and exact bounds on the maximum possible deviation of approximate core payoff vectors from satisfying a law of scarcity are stated in terms of the parameters describing the games. We note that the parameters can, in principle, be estimated. Results are compared to the developments in the literature on matching markets, pregames and general equilibrium. This paper expands on results published in Kovalenkov and Wooders, Economic Theory )to appear).Monotonicity ; cooperative games ; clubs ; games with side payments (TU games) ; cyclic monotonicity ; laws of scarecity ; law of demand ; approximate cores ; effective small groups ; parameterized collection of games

Optimization of the composition of crop collections for ex situ conservation

Many crop genetic resources collections have been established without a clearly defined conservation goal or mandate, which has resulted in collections of considerable size, unbalanced composition and high levels of duplication. Attempts to improve the composition of collections are hampered by the fact that conceptual views to optimize collection composition are very rare. An optimization strategy is proposed herein, which largely builds on the concepts of core collection and core selection. The proposed strategy relies on hierarchically structuring the crop gene pool and assigning a relative importance to each of its different components. Comparison of the resulting optimized distribution of the number of accessions with the actual distribution allows identification of under- and over-representation within a collection. Application of this strategy is illustrated by an example using potato. The proposed optimization strategy is applicable not only to individual genebanks, but also to consortia of cooperating genebanks, which makes it relevant for ongoing activities within projects that aim at sharing responsibilities among institutions on the basis of rational conservation, such as a European genebank integrated system and the global cacao genetic resources network CacaoNet

Cooperative Games in Graph Structure

By a cooperative game in coalitional structure or shortly coalitional game we mean the standard cooperative non-transferable utility game described by a set of payoffs for each coalition that is a nonempty subset of the grand coalition of all players.It is well-known that balancedness is a sufficient condition for the nonemptiness of the core of such a cooperative non-transferable utility game.For this result any information on the internal organization of the coalition is neglected.In this paper we generalize the concept of coalitional games and allow for organizational structure within coalitions.For a subset of players any arbitrarily given structural relation represented by a graph is allowed for.We then consider non-transferable utility games in which a possibly empty set of payoff vectors is assigned to any graph on every subset of players.Such a game will be called a cooperative game in graph structure or shortly graph game.A payoff vector lies in the core of the game if there is no graph on a group of players which can make all of its members better off.We define the balanced-core of a graph game as a refinement of the core.To do so, for each graph a power vector is determined that depends on the relative positions of the players within the graph.A collection of graphs will be called balanced if to any graph in the collection a positive weight can be assigned such that the weighted power vectors sum up to the vector of ones.A payoff vector lies in the balanced-core if it lies in the core and the payoff vector is an element of payoff sets of all graphs in some balanced collection of graphs.We prove that any balanced graph game has a nonempty balanced-core and therefore a nonempty core.We conclude by some examples showing the usefulness of the concepts of graph games and balanced-core.In particular these examples show a close relationship between solutions to noncooperative games and balanced-core elements of a well-defined graph game.This places the paper in the Nash research program, looking for a unifying theory in which each approach helps to justify and clarify the other.cooperative games;graphs