Ch. 8 Resources: Graduate Student Support Programs

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The minimal nilpotent orbit, the Joseph ideal, and differential operators

AbstractFix a simple complex Lie algebra g, not of type G2, F4, or E8. Let Ōmin denote the Zariski closure of the minimal non-zero nilpotent orbit in g, and let g = n+ ⊕ h ⊕ n− be a triangular decomposition. We proveTHEOREM. (1) If g is not of type An then there exists an irreducible component X̄ of Ōmin ∩ n+ such that U(g)/Jo = D(X̄), where Jo is the Joseph ideal and D(X̄) denotes the ring of differential operators on X̄. (2) If g is of type An then for n − 2 of the n irreducible components X̄i of Ōmin∩ n+ there exist (distinct) maximal ideals Ji of U(g) such that U(g)/Ji= D(X̄i)

Integrated weed management strategies for delaying herbicide resistance in wild oats

Les biotypes de folle avoine (Avena fatua) résistants aux herbicides infestent les principales régions céréalières de l'Ouest américain et de l'Ouest canadien. Cet article passe en revue les stratégies de lutte intégrée contre les mauvaises herbes qui peuvent être utilisées pour empêcher ou retarder le développement de la résistance aux herbicides chez la folle avoine. Une stratégie de lutte intégrée contre la folle avoine, destinée à retarder ou à empêcher le développement de la résistance, devrait être basée sur la prévention de l'introduction des grains de folle avoine dans le sol. Deux façons d'y arriver sont d'empêcher l'immigration de graines dans le champ à partir de sources externes, et de réduire ou éliminer la production de graines par la folle avoine déjà présente au champ. Il est de plus en plus évident que le recours à l'utilisation continuelle d'herbicides comme seul moyen de lutte contre les mauvaises herbes n'éliminera pas la folle avoine ni les autres graines de mauvaises herbes de la banque de graines du sol. Au contraire, tout porte à croire que cette pratique va sélectionner des biotypes résistants aux herbicides utilisés, particulièrement là où des herbicides ayant le même mode d'action sont utilisés de façon continue. Il est essentiel, cependant, que les herbicides soient considérés seulement comme une composante d'un système intégré global incluant la lutte culturale et d'autres stratégies de gestion, et que les principes agronomiques soient considérés lors du développement de ce système.Herbicide-resistant biotypes of wild oats (Avena fatua) infest most major cereal producing regions in the western United States and Canada. This paper reviews potential integrated weed management strategies that can be used to prevent or delay selection of herbicide-resistant wild oats plants. An integrated wild oats management strategy to delay or prevent the development of herbicide resistance should be based on preventing the movement of wild oats seed into the soil. Two ways to achieve this are by preventing the immigration of seed into the field from external sources, and by reducing or eliminating seed production by wild oats already in the field. It is becoming increasingly clear that reliance on continuous herbicide useas the sole means of weed control will fail to eliminate wild oats and other weed seed from the soil seedbank. On the contrary, evidence is mounting that this practice will select for biotypes that are resistant to the herbicides used, especially where herbicides of the same mode of action are used continuously. It is essential, therefore, that herbicides be considered as just one component of an overall integrated System together with cultural control and other management strategies, and that agronomic principles be considered when developing this System

Bactericidal activity of the new 4-quinolones DU-6859a and DV-7751a

The bactericidal activity of two new 4-quinolones, DU-6859a and DV-7751a, was investigated against strains of Escherichia coli, Staphylococcus aureus, S. epidermidis, Streptococcus pneumoniae and Enterococcus faecalis. DU-6859a and DV-7751a were more bactericidal than any 4-quinolone tested previously. Furthermore, DU-6859a was unique among 4-quinolones in being able to kill Ent. faecalis after incubation for only 3 h in nutrient broth. The bactericidal mechanisms of DV-7551a were similar to those of other 4-quinolones, but, uniquely, DU-6859a possessed additional bactericidal mechanisms against both Str. pneumoniae and Ent. faecalis. This may explain the unusually potent bactericidal activity of this agent against these species. These results show that DU-6859a is a unique extended-spectrum 4-quinolone, which should prove to be superior to established 4-quinolones

Effect of Hydrostatic Pressure on the Superconductivity in NaxCoO2.yH2O

The effect of hydrostatic pressure on the superconducting transition temperature of Na{0.35}CoO{2}.yH{2}O was investigated by ac susceptibility measurements up to 1.6 GPa. The pressure coefficient of T{c} is negative and the dependence T{c}(p) is nonlinear over the pressure range investigated. The magnitude of the average dlnT{c}/dp=-0.07 GPa^{-1} is comparable to the pressure coefficient of electron-doped high-T{c} copper oxide superconductors with a similar value of T{c}. Our results provide support to the assumption of two-dimensional superconductivity in Na{0.35}CoO{2}.yH{2}O, which is similar to the cuprate systems, and suggest that intercalation of larger molecules may lead to an enhancement of T{c}.Comment: Revised Manuscrip

Qu’apporte l’étude des town meetings à la quête d’une démocratie plus participative et délibérative?

Comme annoncé dans l’introduction, ce numéro spécial de Participations se clôt sur un entretien collectif, mené par Paula Cossart et Andrea Felicetti, rassemblant certains des plus éminents représentants de la recherche sur les town meetings de Nouvelle-Angleterre. Trois ensembles de questions ont été soumis à chaque interviewé, qui y a répondu individuellement par écrit. Hors corrections mineures, le texte des réponses n’a pas été modifié ; mais il a parfois été segmenté de manière à rendre la lecture plus fluide, et à mettre en évidence les interactions entre les différentes perspectives présentes dans ces lignes. La version finale de ce texte a été éditée et approuvée par les chercheurs interrogés

An intravaginal ring for real-time evaluation of adherence to therapy

© 2017 Moss et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Two recent Phase III clinical trials to investigate an intravaginal ring for preventing HIV infection demonstrated that adherence to prescribed device use was a primary driver of efficacy. Surrogate methods for determining adherence in the studies were limited in their inability to monitor temporal patterns of use and allow deconvolution of the effects of adherence and device efficacy on HIV infection rates. To address this issue, we have developed functionality in an intravaginal ring to continuously monitor when the device is being used and maintain a log of adherence that can be accessed by clinicians after it is removed. An electronic module fabricated with common, inexpensive electronic components was encapsulated in a silicone intravaginal ring. The device uses temperature as a surrogate measure of periods of device insertion and removal, and stores a record of the data for subsequent retrieval. The adherence-monitoring intravaginal ring accurately recorded the device status over 33 simulated IN-OUT cycles and more than 1000 measurement cycles in vitro. Following initial in vitro testing in a temperature-controlled chamber, the device was evaluated in vivo in sheep using a predetermined insertion/removal pattern to simulate intravaginal ring use. After insertion into the vaginal cavity of a sheep, the logged data correctly indicated the device status over 29 hours of continuous measurement including three cycles of insertion and removal. The device described here is a promising, low-cost method for real-time adherence assessment in clinical trials involving medicated intravaginal rings or other intravaginal devices

Shape of nanosize superconducting grains: Does it influence pairing characteristics?

The Richardson exact solution for the reduced BCS Hamiltonian is applied to examine how sensitive are the pairing characteristics (condensation energy, spectroscopic gap, parity gap) to a specific configuration of single-electron energy levels in nanosize metallic grains. Using single-electron energy spectra in parallelepiped-shaped potential boxes with various volumes and aspect ratios as a model of energy levels in grains, we show that this sensitivity is extremely high. Just due to such an extreme sensitivity, the detailed shape of grains cannot be detected through the pairing characteristics, averaged over an ensemble of grains, even in the case of relatively small size dispersion within this ensemble. We analyse the effect of the pairing interaction on the excited-level spacings in superconducting grains and comment on the influence of shape-dependent fluctuations in single-electron energy spectra on the possibility to reveal this effect through tunnelling measurements.Comment: 13 pages, 5 figures, to be published in Solid State Communications, E-mail addresses: [email protected], [email protected], [email protected]

A demand-driven approach for a multi-agent system in Supply Chain Management

This paper presents the architecture of a multi-agent decision support system for Supply Chain Management (SCM) which has been designed to compete in the TAC SCM game. The behaviour of the system is demand-driven and the agents plan, predict, and react dynamically to changes in the market. The main strength of the system lies in the ability of the Demand agent to predict customer winning bid prices - the highest prices the agent can offer customers and still obtain their orders. This paper investigates the effect of the ability to predict customer order prices on the overall performance of the system. Four strategies are proposed and compared for predicting such prices. The experimental results reveal which strategies are better and show that there is a correlation between the accuracy of the models' predictions and the overall system performance: the more accurate the prediction of customer order prices, the higher the profit. © 2010 Springer-Verlag Berlin Heidelberg