Aspects of resistance in deepwater rice to the stem nematode Ditylenchus angustus

Une technique utilisant les plants de riz a été mise au point pour cribler la résistance du riz flottant à #Ditylenchus angustus$. Cette technique copie l'infestation naturelle à partir de l'eau et permet une infestation de 100$ est rapide sur les cvs sensibles (la durée du cycle est de 10 à 20 jours, à 30°C). L'expression des symptômes et la multiplication du nématode ont été étudiées sur une série de cultivars et lignées de riz flottant, tant sensibles que résistants. La résistance est en partie conférée par une réaction nécrotique rapide de l'hôte lors de la prise de nourriture du nématode. Cette réaction est présente chez quelques lignées (CNL 319, Bazail 65, Rayada 16-02, Rayada 16-03, Rayad 16-06 à 16-09) qui se sont montrées en champ résistantes en divers endroits et au cours du temps. Une telle réaction est qualitativement différente de celle, bien connue, montrée par les plantes sensibles, et peut ainsi fournir une base en vue de la sélection génotypique. La relation entre profondeur de l'eau et taille des plants de riz est d'une importance cruciale pour le déclenchement de l'infestation et le développement des symptômes. #D. angustus$ pénètre dans les plants d'abord au niveau de la surface de l'eau, aussi une submersion des gaînes des feuilles retardera-t-elle l'infestation. Les symptômes se développent plus rapidement si, durant l'infestation, le niveau de l'eau est voisin de ou très peu inférieur à celui du collet situé au sommet de la gaîne foliaire. L'expression des symptômes, et par conséquent les dégâts précoces, sont ralentis en abaissant le niveau de l'eau. (Résumé d'auteur

Leadership between decks: a synthesis and development of engagement and resistance theories of leadership based on evidence from practice in Royal Navy warships

Purpose To understand the role of interaction in the process of leadership. Interaction has been claimed to be a leadership competence in earlier research into leadership in the Royal Navy. The aim of this research is to define how interaction works within naval teams. Design/methodology/approach The research uses Grounded Theory. Following a series of leadership discussions in separate focus groups, discussion topics were coded and subjected to recursive qualitative analysis. The grounded approach is used to synthesise and develop existing leadership theory strands as well as to extend the trait-process approach to leadership. Findings The research discovers the key interaction behaviours of engagement, disengagement and levelling. Our findings support recent developments in follower-centric perceptions of leadership and in interaction specifically. We develop engagement theory by combining it with the less well researched area of leadership resistance. We then re-frame resistance as social levelling, a more comprehensive interaction mechanism. Research limitations/implications The research is highly contextual because of its qualitative approach. Some of the detailed reactions to leadership behaviours may not found in other naval or military teams and are unlikely to be generalizable to non-military environments. However, the mechanism described, that of engagement, disengagement and levelling is considered highly generalizable if not universal. Rather than develop new theory fragments in an already confusing research environment, we fuse engagement and resistance theory to extend trait-process theories of leadership. The result is a coherent and integrative model of leadership dynamics which frames leadership in the mundane interaction of leaders and followers. Practical implications Interaction as a competence is strongly supported as is the encouragement of cultures which promote interaction. Selection procedures for future leaders should include interaction skills. The use of subtle methods of resistance are highlighted. Such methods may indicate poor interaction long before more overt forms of resistance are apparent. Originality/value This research uniquely uses Grounded Theory to extend current theories (competence based leadership and trait-process theories of leadership), explaining the complexity of leadership-interaction. The research also synthesises and develops engagement and levelling (resistance to leadership) theories for the first time. As such the project suggests a full range model of follower response to leadership including subtle forms of resistance to power. The value of group-level analysis using focus groups is recommended, especially for other collective leader-follower approaches to leadership. The research is of interest to those studying leadership process theories, competencies, leader-follower traditions, engagement and power/resistance research

Recreational Fishing Initiatives Fund Final Report: Can recreational fishers provide a cost effective means for monitoring artificial reefs?

Artificial reefs have been constructed and deployed in over 50 countries around the world to enhance the productivity of aquatic habitats and fishing experiences. In April 2013, two purpose-built concrete artificial reefs were deployed in Geographe Bay, Western Australia to provide additional fish habitat and increase upwelling and thus enhance recreational fishing opportunities. Due to the relatively high cost of planning, purchasing and deploying these structures, it is important to understand spatial and temporal usage of the reef by fish assemblages, in order to determine the extent to which fishing opportunities are actually enhanced. One potential method to reduce monitoring costs is to utilise volunteers from the general public to collect data, i.e. citizen science. The overall objective of this project was to determine whether recreational fishers, through a citizen science program, could potentially provide an effective means for monitoring artificial reefs

Avian Influenza among Waterfowl Hunters and Wildlife Professionals

We report serologic evidence of avian influenza infection in 1 duck hunter and 2 wildlife professionals with extensive histories of wild waterfowl and game bird exposure. Two laboratory methods showed evidence of past infection with influenza A/H11N9, a less common virus strain in wild ducks, in these 3 persons

Optimal low-thrust trajectories to asteroids through an algorithm based on differential dynamic programming

In this paper an optimisation algorithm based on Differential Dynamic Programming is applied to the design of rendezvous and fly-by trajectories to near Earth objects. Differential dynamic programming is a successive approximation technique that computes a feedback control law in correspondence of a fixed number of decision times. In this way the high dimensional problem characteristic of low-thrust optimisation is reduced into a series of small dimensional problems. The proposed method exploits the stage-wise approach to incorporate an adaptive refinement of the discretisation mesh within the optimisation process. A particular interpolation technique was used to preserve the feedback nature of the control law, thus improving robustness against some approximation errors introduced during the adaptation process. The algorithm implements global variations of the control law, which ensure a further increase in robustness. The results presented show how the proposed approach is capable of fully exploiting the multi-body dynamics of the problem; in fact, in one of the study cases, a fly-by of the Earth is scheduled, which was not included in the first guess solution

A weakly stable algorithm for general Toeplitz systems

We show that a fast algorithm for the QR factorization of a Toeplitz or Hankel matrix A is weakly stable in the sense that R^T.R is close to A^T.A. Thus, when the algorithm is used to solve the semi-normal equations R^T.Rx = A^Tb, we obtain a weakly stable method for the solution of a nonsingular Toeplitz or Hankel linear system Ax = b. The algorithm also applies to the solution of the full-rank Toeplitz or Hankel least squares problem.Comment: 17 pages. An old Technical Report with postscript added. For further details, see http://wwwmaths.anu.edu.au/~brent/pub/pub143.htm

Extrapolating SMBH correlations down the mass scale: the case for IMBHs in globular clusters

Empirical evidence for both stellar mass black holes M_bh<10^2 M_sun) and supermassive black holes (SMBHs, M_bh>10^5 M_sun) is well established. Moreover, every galaxy with a bulge appears to host a SMBH, whose mass is correlated with the bulge mass, and even more strongly with the central stellar velocity dispersion sigma_c, the `M-sigma' relation. On the other hand, evidence for "intermediate-mass" black holes (IMBHs, with masses in the range 1^2 - 10^5 M_sun) is relatively sparse, with only a few mass measurements reported in globular clusters (GCs), dwarf galaxies and low-mass AGNs. We explore the question of whether globular clusters extend the M-sigma relationship for galaxies to lower black hole masses and find that available data for globular clusters are consistent with the extrapolation of this relationship. We use this extrapolated M-sigma relationship to predict the putative black hole masses of those globular clusters where existence of central IMBH was proposed. We discuss how globular clusters can be used as a constraint on theories making specific predictions for the low-mass end of the M-sigma relation.Comment: 14 pages, 3 figures, accepted for publication in Astrophysics and Space Science; fixed typos and a quote in Sec.