The calorimetry at the future e+ e- linear collider

The physics programme for a coming electron linear collider is dominated by events with final states containing many jets. We develop in this paper the opinion that the best approach is to optimise the independent measurement of the tracks in the tracker, the photons in the electromagnetic calorimeter and the neutral hadrons in the camorimetry, together with a good lepton identification. This can be achieved with a high granularity calorimetry providing particle separation, through an efficient energy flow algorithm.Comment: 7 pages, 6 Postscript figures, to appear in the Proceedings of the APS / DPF / DPB Summer Study on the Future of Particle Physics (Snowmass 2001), Snowmass, Colorado, 30 Jun - 21 Jul 200

Experimental Study of the Transformation-Induced Plasticity in a Cr-Ni-Mo-Al-Ti Steel

This paper shows experimental results concerning the martensitic transformation and the transformation-induced plasticity under multiaxial loading. The material investigated is a Cr-Ni-Mo-Al-Ti steel, which is submitted to a γ → α' martensitic phase transformation under an applied stress. The specimens are thin tubes loaded in tension-torsion. The tests were specially designed to provide information on classical questions related with transformation plasticity and the interaction between applied stresses and phase transformations in the case of tension-shear loadings : effect of the applied stresses on Ms temperature, definition of the transformation-induced plasticity (flow intensity, direction in stress space, evolution vs phase change), eventual presence of internal stresses. Some of the answers given by the present study confirm the usual assumptions, but the analysis of the tests also reveals new effects not predicted by the classical theories proposed to quantify the transformation induced plasticity phenomenon

ABC Transporter Required for Intercellular Transfer of Developmental Signals in a Heterocystous Cyanobacterium

In the filamentous cyanobacterium Anabaena, patS and hetN encode peptide-derived signals with many of the properties of morphogens. These signals regulate the formation of a periodic pattern of heterocysts by lateral inhibition of differentiation. Here we show that intercellular transfer of the patS- and hetN-dependent developmental signals from heterocysts to vegetative cells requires HetC, a predicted ATP-binding cassette transporter (ABC transporter). Relative to the wild type, in a hetC mutant differentiation resulted in a reduced number of heterocysts that were incapable of nitrogen fixation, but deletion of patS or hetN restored heterocyst number and function in a hetC background. These epistasis results suggest that HetC is necessary for conferring self-immunity to the inhibitors on differentiating cells. Nine hours after induction of differentiation, HetC was required for neither induction of transcription of patS nor intercellular transfer of the patS-encoded signal to neighboring cells. Conversely, in strains lacking HetC, the patS- and hetN-encoded signals were not transferred from heterocyst cells to adjacent vegetative cells. The results support a model in which the patS-dependent signal is initially transferred between vegetative cells in a HetC-independent fashion, but some time before morphological differentiation of heterocysts is complete, transfer of both signals transitions to a HetC-dependent process

Identification and Characterization of Fungal Isolates from Land-applied Sewage Sludge

Approximately eight million dry tons of sewage sludge is generated in the U.S. each year, with more than half of that now land-applied as the primary method of disposal. Despite the proliferation of this practice, little is known about the microbial constituents of these noxious materials. To address this knowledge gap, we isolated and characterized fungi present in archived samples of land-disposed sewage sludge collected from the Snoqualmie National Forest (Washington State). Sludge samples were resuspended in sterile water and 15 fungal isolates were selected and purified on sabouraud dextrose agar plates supplemented with 50 mg/L of chloramphenicol. Fungal morphology was assessed and photodocumented following growth on sabouraud dextrose agar, potato dextrose agar, yeast maltose agar, and malt extract agar. Additionally, pH and temperature tolerance was assessed by growth in liquid cultures of sabouraud dextrose broth from 0 ºC to 50 ºC and determined from pH 2 to 11 at 28 ºC. Carbon source utilization was assessed using Biolog Filamentous Fungi plates. Amplification and sequencing of the ITS region, commonly used in fungal phylogenetic analysis, is in progress to identify each isolate. Phenotypic assessments of growth, carbon utilization, and lactophenol cotton blue staining revealed that sludge-associated fungi are quite varied in size and appearance, but commonly grow in a mesophilic range (10-40 ºC and pH 4-10). Interspecies variation is further evident in the percentage of 31 carbon sources utilized (63-100%). To our knowledge, this work represents the first reported assessment of the fungal community in sewage sludge wastes disposed in the Snoqualmie National Forest

Characterizing the Volatilome of Land-disposed Sewage Sludge Under Seasonal Temperature Regimes

About eight million dry tons of sewage sludge waste is generated in the US annually, with more than half of that now land-disposed on agricultural and forested lands. Though containing essential plant nutrients, sludge also harbors complex mixtures of volatile organic compounds (VOCs) that result in toxic emissions therefrom. While ecotoxic impacts to sludged ecosystems are a primary concern, the stifling emissions are most obvious to and disconcerting for the public, which has led to increasing concerns for the safety of this practice. The large-scale disposal of sludge in the temperate rainforests of the Puget Sound Watershed has resulted in acute toxicity to macrobiota, and despite escalating concerns for detrimental impacts, little is known about the total VOC inventories, or “volatilomes,” of these complex wastes. To address this knowledge gap, we characterized VOC emissions from forest-disposed sewage sludge over a range of seasonal temperature regimes. We also incubated sludge samples at the more extreme 100 o C to assess the “complete volatilome.” After 1-hr incubations in gastight vials, VOCs accumulated in the headspace were sampled with a gastight syringe and analyzed with gas chromatography-mass spectrometry to generate distinct chemical fingerprints of sludge sample volatilomes over the range of temperatures. Total integrated chromatographic peak areas increased with temperature, indicating increased VOC production. Sludge volatilomes were dominated by a multitude of aliphatics and aromatics, with comparatively lesser emissions of alcohols, esters, aldehydes, terpenes, and nitrogen-, sulfur-, and halogen-containing compounds

Contribution of the d-Serine-Dependent Pathway to the Cellular Mechanisms Underlying Cognitive Aging

An association between age-related memory impairments and changes in functional plasticity in the aging brain has been under intense study within the last decade. In this article, we show that an impaired activation of the strychnine-insensitive glycine site of N-methyl-d-aspartate receptors (NMDA-R) by its agonist d-serine contributes to deficits of synaptic plasticity in the hippocampus of memory-impaired aged rats. Supplementation with exogenous d-serine prevents the age-related deficits of isolated NMDA-R-dependent synaptic potentials as well as those of theta-burst-induced long-term potentiation and synaptic depotentiation. Endogenous levels of d-serine are reduced in the hippocampus with aging, that correlates with a weaker expression of serine racemase synthesizing the amino acid. On the contrary, the affinity of d-serine binding to NMDA-R is not affected by aging. These results point to a critical role for the d-serine-dependent pathway in the functional alterations of the brain underlying memory impairment and provide key information in the search for new therapeutic strategies for the treatment of memory deficits in the elderly

Testing the Higgs Mechanism in the Lepton Sector with multi-TeV e+e- Collisions

Multi-TeV e+e- collisions provide with a large enough sample of Higgs bosons to enable measurements of its suppressed decays. Results of a detailed study of the determination of the muon Yukawa coupling at 3 TeV, based on full detector simulation and event reconstruction, are presented. The muon Yukawa coupling can be determined with a relative accuracy of 0.04 to 0.08 for Higgs bosons masses from 120 GeV to 150 GeV, with an integrated luminosity of 5 inverse-ab. The result is not affected by overlapping two-photon background.Comment: 6 pages, 2 figures, submitted to J Phys G.: Nucl. Phy

Generic and Layered Framework Components for the Control of a Large Scale Data Acquisition System

The complexity of today's experiments in High Energy Physics results in a large amount of readout channels which can count up to a million and above. The experiments in general consist of various subsystems which themselves comprise a large amount of detectors requiring sophisticated DAQ and readout electronics. We report here on the structured software layers to control such a data acquisition system for the case of LHCb which is one of the four experiments for LHC. Additional focus is given on the protocols in use as well as the required hardware. An abstraction layer was implemented to allow access on the different and distinct hardware types in a coherent and generic manner. The hierarchical structure which allows propagating commands down to the subsystems is explained. Via finite state machines an expert system with auto-recovery abilities can be modeled

Rewriting System for Profile-Guided Data Layout Transformations on Binaries

International audienceCareful data layout design is crucial for achieving high performance. However exploring data layouts is time-consuming and error-prone, and assessing the impact of a layout transformation on performance is difficult without performing it. We propose to guide application programmers through data layout restructuring by providing a comprehensive multidimensional description of the initial layout, built from trace analysis, and then by giving a performance evaluation of the transformations tested and an expression of each transformed layout. The programmer can limit the exploration to layouts matching some patterns. We apply this method to two multithreaded applications. The performance prediction of multiple transformations matches within 5% the performance of hand-transformed layout code