ATM network striping

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (leaves 134-136).by Michael Ismert.M.Eng

Outils d'évaluation de la biodisponibilité des contaminants dans les sols et apport en évaluation des risques pour les écosystèmes.

p71 à 87: texte p85-111: diaporama conférenceNational audienceLa biodisponibilité est la part des contaminants du milieu disponible pour l'assimilation par les organismes. Elle peut être déterminée par mesure des effets (= biodisponibilité toxicologique) et/ou de la bioaccumulation (= biodisponibilité environnementale) des contaminants chez des organismes exposés en laboratoire ou in situ à des sols contaminés. Des exemples d'utilisation des escargots et des plantes pour évaluer la biodisponibilité sont présentés. http://www2.ademe.fr/servlet/KBaseShow?sort=-1&cid=96&m=3&catid=1014

Intraspecific adaptive response of Periconia macrospinosa, a ubiquitous root-associated fungus, to persistent salinity stress provides evidence for its adaptive variability and high-osmolarity glycerol pathway mediated adaptive response

Master of ScienceDepartment of BiologyAri M JumpponenRoot associated fungi are critical to environmental success of their plant hosts. Whether through their interactions with hosts, nutrient recycling, decomposition, or even contribution to soil structure, soil-dwelling fungi play a pivotal role in environmental preservation and function. As climate change continues to affect and change patterns in climate, researchers are increasingly concerned about the impacts our global environments may endure as a result. In a terrestrial ecosystem, mean annual precipitation (MAP) is an important control of biological productivity. As water leaves a system, via evapotranspiration, mass flow, surface flow, or other means, salts remain and concentrate in soils causing salinity stress for organisms that remain. This increasing salt concentration is a major stressor for organisms and requires specialized osmoadaptive responses. Plant communities as well as those of soil-dwelling fungi and bacteria change along precipitation gradients, indicating their responses to water availability. However, it is less certain if conspecific organisms also differ across similar gradients, especially in their abilities to tolerate salt stress. To investigate the inter- and intraspecific adaptive responses of root-associated ascomycetes to salinity, we devised an experiment wherein conspecific isolates representing five ascomycete species were subjected to increasing concentrations of salinity in an effort to quantify and compare the effective dose of salt (NaCl) necessary to limit colony growth by 50% (ED50). For each of the five species, we selected three conspecifics originating from drier “arid” environments and compared those to three conspecifics originating from wetter “mesic” environments. We hypothesized that (1) ascomycete species differ in their growth response to salinity across species; (2) conspecific strains from drier sites have greater salt tolerance than those from more mesic sites. Each isolate was tested three times in triplicate and exposed to four levels of NaCl concentrations in a quad-plate. We measured colony growth and used regression analyses to estimate the isolates’ ED50. In support of our first hypothesis, we observed that species differed in their growth response to salinity according to ED50. However, we observed no consistent, strong evidence to support our second hypothesis. Still, we observed non-significant differences in ED50 within three species observed, partial support in Periconia macrospinosa isolates and the most significant difference across sites within Fusarium cf. equiseti isolates. While isolate results within F. cf. equiseti do support our second hypothesis, Periconia macrospinosa appear to demonstrate an inverse response. This coupled with the non-significant differences between ED50 results across site conditions of the other three species – our second hypothesis was rejected. To further investigate the underlying mechanisms and differences in adaptive response among conspecific isolates, we designed an experiment in which two isolates, DS 1091 and DS 0982, of Periconia macrospinosa that differed most in their salt tolerance as inferred from NaCl ED50 estimated in the experiment described above were subjected to prolonged salinity stress followed by proteomic analysis. The selection of Periconia macrospinosa isolates over Fusarium equiseti isolates was based on the species’ critical importance globally in ecosystems experiencing low nutrient and MAP inputs as well as the availability of a recently annotated genome. We hypothesized that (3) the highest and lowest performing strains within a species will differ in their proteomic profiles; (4) colony expansion under saline stress (ED50) will correlate with cell wall related protein abundances under salt stress (signaling cell wall modifications); (5) similarly to the cell wall associated proteins, colony growth (ED50) will correlate with plasma membrane related protein abundances under salt stress (signaling cell membrane alterations); (6) the mitogen-activated protein kinase (MAPK) signaling pathway will be one strategy for tolerating prolonged salinity amongst the conspecifics (suggesting “compatible-solute” strategy); and, (7) conspecifics associated with the highest ED50 will demonstrate greater abundance of proteins involved in salt-tolerant strategies such as cell wall, plasma membrane, and MAPK-related proteins than their counterparts originating from more mesic sites. Our third hypothesis was supported as the two isolates demonstrated unique proteomic profiles both with and without salinity induced responses. Our fourth and fifth hypotheses, which proposed correlation between isolate colony growth and the abundance profiles of proteins involved in cell walls and cell membranes respectively, were also supported by our proteomic data. The fourth hypothesis was reinforced by our proteomic analysis of our high-ED50 isolate, DS 0982, through the upregulated chitin synthase coupled with downregulation of chitinase demonstrating an investment in cell wall maintenance. The fifth hypothesis was supported through the evident DS 0982 responses to salinity where indicators of sphingolipid biosynthetic processing and ergosterol biosynthesis were observed. Specifically, support for the cell membrane related protein increase correlated with the colony growth was through ergosterol biosynthesis contributors CDP-diacylglycerol synthase, sterol C-14 reductase-like protein, and sterol 24-C methyltransferase. The sixth hypothesis, which focused on the positive correlation between colony growth and MAPK signaling interactions was also supported. The MAPK high-osmolarity glycerol HOG pathway regulates and initiates osmoadaptive responses within the cell, the most critical of which being the production of the compatible-solute – glycerol. This hypothesis was strongly supported due to observations of abundance differences in response to salinity of several key HOG pathway MAPK proteins, most notably Gdp1 the downstream initiator of glycerol production. Finally, our seventh hypothesis was supported by the observed inverse responses between our two conspecific isolates. As per our hypothesis, the isolate with greatest ED50, DS 0982, did indeed have the greatest abundance of proteins involved with osmoadaptive strategy across the board from those involved in cell wall modifications such as chitin synthase, to proteins involved in plasma membrane amendments such as including such observations as C-14 reductase-like protein, and even the critical MAPK compatible osmolyte production initiator protein Gdp1. Understanding soil-inhabiting and root-associated fungi is critical to ecosystem health. Whether through providing nutrient cycling and ecosystem services, or direct interactions with host plants, fungal impacts cannot be ignored. Through the effects of climate change and corresponding changes in precipitation, soil salinization is a major threat to plant and animal health as well as the overall function of our natural world. This research aims to fill the gap in our knowledge on the impact of salinity toward root-associated fungi and their limits in salt-tolerance both within and across species. Further, this study aids in identifying varying functional adaptations soil-dwelling fungi depend on for survival in response to salt stress in soil matrices

The Iowa Homemaker vol.29, no.5

Give a Cookbook for Christmas, Margaret Leveson, page 3 Here’s What’s Open for you in TV, Barbara Short, page 4 What’s New, Virginia Foth, page 6 Holiday Treats, Marian Ismert, page 7 We’re Square Dancing Tonight, Elizabeth Fox, page 8 Alums in the News, Marjorie Miller, page 10 Here’s an Idea, Janet Sutherland, page 12 For the Men on Vicky’s Gift List, Frances Bosnak, page 1

Effects of Feeding Fluorescent Brightener 28 and Blue Dextran to European Corn Borer Larvae

The European corn borer (ECB), Ostrinia nubilalis, is a common pest for corn crops in the United States and most of Europe (Hudan and LeRoux, 1986). Use of traditional pesticides to control ECB has resulted in the development of resistance in pest populations and significant loss of important biological control species. As such, novel methods, such as use of RNA interference (RNAi), are necessary to overcome resistance to traditional pesticides and protect non-target insects. RNAi takes advantage of intrinsic pathways that use long double-stranded RNAs (dsRNAs) to suppress the expression of specific genes (Zhang et al., 2010), however, many insects do not produce an efficient RNAi response, at least partially as a result of the presence of double-stranded ribonucleases (dsRNases) that degrade the dsRNAs prior to incorporation into the RNAi pathway (Kim et al., 2015). These dsRNases are present in the guts of many species, including ECB and are a powerful factor limiting the efficacy of RNAi. We hypothesize that applying dsRNA when expression of dsRNases is low (such as in young ECB larvae) and degrading the gut lining will minimize contact between dsRNAs and dsRNases and increase RNAi efficiency. Fluorescent Brightener 28 (FB28) is a chemical that has been used previously to damage insect gut linings and so is a good candidate for performing these experiments (Zhang et al., 2010). In addition, blue dextran (BD) is also necessary as a marker to demonstrate successful weakening and increased permeability of the gut, however, it is still unclear what concentrations of these chemicals ECB larvae will tolerate without significant adverse effects. Accordingly, these experiments were designed to identify the optimum levels of FB28 and BD needed in the diet of larval ECB for clear visualization of gut disruption

Unbounded Derivations of C*-algebras and the Heisenberg Commutation Relation

This dissertation investigates the properties of unbounded derivations on C*-algebras, namely the density of their analytic vectors and a property we refer to as kernel stabilization. We focus on a weakly-defined derivation δD which formalizes commutators involving unbounded self-adjoint operators on a Hilbert space. These commutators naturally arise in quantum mechanics, as we briefly describe in the introduction. A first application of kernel stabilization for δD shows that a large class of abstract derivations on unbounded C*-algebras, defined by O. Bratteli and D. Robinson, also have kernel stabilization. A second application of kernel stabilization provides a sufficient condition for when a pair of self-adjoint operators which satisfy the Heisenberg Commutation Relation on a Hilbert space must both be unbounded. A directly related classification program is of pairs of unitary group representations which satisfy the Weyl Commutation Relation on a Hilbert space. The famous Stone-von Neumann Theorem classifies these pairs when the group is locally compact abelian. In collaboration with L. Huang, we extend the Stone-von Neumann Theorem to a uniqueness statement for representations of C*-dynamical systems on Hilbert K(H)-modules. Advisors: A.P. Donsig and D.R. Pitt