A First Step Towards Automatically Building Network Representations

To fully harness Grids, users or middlewares must have some knowledge on the topology of the platform interconnection network. As such knowledge is usually not available, one must uses tools which automatically build a topological network model through some measurements. In this article, we define a methodology to assess the quality of these network model building tools, and we apply this methodology to representatives of the main classes of model builders and to two new algorithms. We show that none of the main existing techniques build models that enable to accurately predict the running time of simple application kernels for actual platforms. However some of the new algorithms we propose give excellent results in a wide range of situations

Energy Dependence of Cross Sections for Stretched States Excited in (p,n) Reactions

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

High-Spin States Excited Via (p,n) Reactions

This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit

Regional Corn Planting Date Recommendations for Iowa

Corn is planted earlier every year and thisis one important component in maximizing grain yield. In 2009, 47% of the statewide corn crop was planted by approximately April 26. This was four days earlier than the previous 5-year average (USDA NASS, 2009). Earlier planting dates are attributed to several causes: larger acreage per producer, less spring tillage, advancements in hybrids, increased tile drainage, and improved seed treatments. The start of corn planting is generally related to the date when the soil temperature reaches 50°F (10°C) or greater

Stretched State Excitations in the 26-Mg(p,n)26-Al Reaction at 134 MeV

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Acid pH activation of the PmrA/PmrB two-component regulatory system of Salmonella enterica

Acid pH often triggers changes in gene expression. However, little is known about the identity of the gene products that sense fluctuations in extracytoplasmic pH. The Gram-negative pathogen Salmonella enterica serovar Typhimurium experiences a number of acidic environments both inside and outside animal hosts. Growth in mild acid (pH 5.8) promotes transcription of genes activated by the response regulator PmrA, but the signalling pathway(s) that mediates this response has thus far remained unexplored. Here we report that this activation requires both PmrA's cognate sensor kinase PmrB, which had been previously shown to respond to Fe(3+) and Al(3+), and PmrA's post-translational activator PmrD. Substitution of a conserved histidine or of either one of four conserved glutamic acid residues in the periplasmic domain of PmrB severely decreased or abolished the mild acid-promoted transcription of PmrA-activated genes. The PmrA/PmrB system controls lipopolysaccharide modifications mediating resistance to the antibiotic polymyxin B. Wild-type Salmonella grown at pH 5.8 were > 100 000-fold more resistant to polymyxin B than organisms grown at pH 7.7. Our results suggest that protonation of the PmrB periplasmic histidine and/or of the glutamic acid residues activate the PmrA protein, and that mild acid promotes cellular changes resulting in polymyxin B resistance

High-Spin "Stretched" States Excited in (p,n) Reactions

This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit

Measurements of Gamow-Teller Strength for Double-Beta Decaying Nuclei Via the (p,n) Reaction at 134 MeV

This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit

P-A Measurements in the 48-Ca(p,n)48-Sc Reaction at 135 MeV

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

High-Spin States in Nuclei Excited Via the (p,n) Reactions

Supported by the National Science Foundation and Indiana Universit