83,069 research outputs found
Control of bacterial disease in small scale fresh-water aquaculture: Project R0754. Project completion report December 1998 - May 1999
The work presented here represents an 18-month study to examine the relationship between environmental conditions, bacterial load in the water and bacteria levels in tissue macrophages of a range of clinically healthy freshwater fish species, farmed in a range of culture systems in Thailand and Vietnam. Preliminary assessment was made of the clinical significance of the macrophage bacterial load. The aim of this work was to improve production in fresh-water aquaculture through the control of clinical bacterial disease and subclinical infection, and to identify management practices most effective in promoting fish health. [PDF contains 37 pages
In-migrants and exclusion in east African rangelands: access, tenure and conflict
East African rangelands have a long history of population mobility linked to competition over key resources, negotiated access, and outright conflict. Both in the literature and in local discourse, in-migration is presented as leading to increased competition, driving poverty and social exclusion on the one hand, and conflict and violence on the other. Current analyses in developing countries identify economic differences, ethnic fault lines, ecological stresses and a breakdown in state provision of human and constitutional rights as factors in driving conflict. The present paper explores this interaction of in-migration and conflict with respect to Kenyan and Tanzanian pastoralist areas and populations. Using quantitative and qualitative methods, patterns of resource access and control in Kenya and Tanzania Maasailand are explored in terms of the ways land and livestock are associated with migration status, ethnicity and wealth or political class. Contrasts and similarities between the two national contexts are used to develop a better understanding of the ways these factors operate under different systems of tenure and access. The conclusion briefly considers implications of these patterns, their potential for exacerbating poverty, and policies for minimising social exclusion and conflict in East African rangelands. / Abstract in French: Les prairies d'Afrique orientale connaissent depuis longtemps une mobilité des populations, liée aux problèmes de concurrence pour les ressources clés, d'accès négocié et de conflits pures et simples. Dans la littérature comme dans le discours local, l'immigration interne est présentée comme cause de concurrence accrue, motrice de pauvreté et d'exclusion sociale d'une part, et de conflit et de violence d'autre part. Des analyses menées actuellement dans les pays en développement identifient comme facteurs moteurs de conflit des écarts économiques, des failles ethniques, des tensions écologiques et une détérioration des droits humains et constitutionnels. Cet article examine l'interaction entre immigration interne et conflit au sein des régions et populations pastorales du Kenya et de la Tanzanie. Il utilise des méthodes quantitatives et qualitatives pour étudier les modèles d'accès et de contrôle des ressources dans le pays masaï du Kenya et de la Tanzanie en termes d'association des terres et du bétail au statut d'immigration, à l'ethnicité et à la catégorie de richesse ou politique. Les contrastes et similarités entre les deux contextes nationaux servent à mieux comprendre le mode de fonctionnement de ces facteurs dans des régimes fonciers et systèmes d'accès différents. La conclusion examine brièvement les implications de ces modèles, leur capacitéà exacerber la pauvreté et les politiques de minimisation de l'exclusion sociale et des conflits dans les prairies d'Afrique orientale
Search for Contact Interactions in the Dimuon Final State at ATLAS
The Standard Model has been successful in describing many fundamental aspects
of particle physics. However, there are some remaining puzzles that are not
explained within the context of its present framework. We discuss the
possibility to discover new physics in the ATLAS Detector via a four-fermion
contact interaction, much in the same way Fermi first described Weak
interactions. Using a simple ratio method on dimuon events, we can set a 95%
C.L. lower limit on the effective scale Lambda = 7.5 TeV (8.7 TeV) for the
constructive Left-left Isoscalar Model of quark compositeness with 100 pb^-1
(200 pb^-1) of data at sqrt{s} = 10 TeV.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July
2009, eConf C09072
Research on graphite reinforced glass matrix composites
A broad group of fibers and matrices were combined to create a wide range of composite properties. Primary material fabrication procedures were developed which readily permit the fabrication of flat plate and shaped composites. Composite mechanical properties were measured under a wide range of test conditions. Tensile, flexure mechanical fatigue, thermal fatigue, fracture toughness, and fatigue crack growth resistance were evaluated. Selected fiber-matrix combinations were shown to maintain their strength at up to 1300 K when tested in an inert atmosphere. Composite high temperature mechanical properties were shown to be limited primarily by the oxidation resistance of the graphite fibers. Composite thermal dimensional stability was measured and found to be excellent
Coz: Finding Code that Counts with Causal Profiling
Improving performance is a central concern for software developers. To locate
optimization opportunities, developers rely on software profilers. However,
these profilers only report where programs spent their time: optimizing that
code may have no impact on performance. Past profilers thus both waste
developer time and make it difficult for them to uncover significant
optimization opportunities.
This paper introduces causal profiling. Unlike past profiling approaches,
causal profiling indicates exactly where programmers should focus their
optimization efforts, and quantifies their potential impact. Causal profiling
works by running performance experiments during program execution. Each
experiment calculates the impact of any potential optimization by virtually
speeding up code: inserting pauses that slow down all other code running
concurrently. The key insight is that this slowdown has the same relative
effect as running that line faster, thus "virtually" speeding it up.
We present Coz, a causal profiler, which we evaluate on a range of
highly-tuned applications: Memcached, SQLite, and the PARSEC benchmark suite.
Coz identifies previously unknown optimization opportunities that are both
significant and targeted. Guided by Coz, we improve the performance of
Memcached by 9%, SQLite by 25%, and accelerate six PARSEC applications by as
much as 68%; in most cases, these optimizations involve modifying under 10
lines of code.Comment: Published at SOSP 2015 (Best Paper Award
17Beta-estradiol modulates gastroduodenal preneoplastic alterations in rats exposed to the carcinogen N-methyl-N'-nitro-nitrosoguanidine
- …