4,232 research outputs found
Photoproduction at collider energies: from RHIC and HERA to the LHC
We present the mini-proceedings of the workshop on ``Photoproduction at
collider energies: from RHIC and HERA to the LHC'' held at the European Centre
for Theoretical Studies in Nuclear Physics and Related Areas (ECT*, Trento)
from January 15 to 19, 2007. The workshop gathered both theorists and
experimentalists to discuss the current status of investigations of high-energy
photon-induced processes at different colliders (HERA, RHIC, and Tevatron) as
well as preparations for extension of these studies at the LHC. The main
physics topics covered were: (i) small- QCD in photoproduction studies with
protons and in electromagnetic (aka. ultraperipheral) nucleus-nucleus
collisions, (ii) hard diffraction physics at hadron colliders, and (iii)
photon-photon collisions at very high energies: electroweak and beyond the
Standard Model processes. These mini-proceedings consist of an introduction and
short summaries of the talks presented at the meeting
Agrobiodiversidade nos quintais agroflorestais em trĂȘs assentamentos na AmazĂŽnia Central.
A agrobiodiversidade dos quintais agroflorestais vem sendo destacada como determinante da sustentabilidade das comunidades tradicionais na AmazĂŽnia. Contudo, trabalhos voltados para anĂĄlise desta diversidade de espĂ©cies agrĂcolas e arbĂłreas, como componentes de quintais agroflorestais, em assentamentos em ĂĄreas de terra firme, sĂŁo pouco discutidos, bem como, as razĂ”es do seu estabelecimento. O objetivo deste trabalho foi avaliar a agrobiodiversidade nos quintais de trĂȘs projetos de assentamentos mo Estado do Amazonas
Multi-experiment assessment of soil nitrous oxide emissions in sugarcane
Soil nitrous oxide (N 2O) fluxes comprise a significant part of the greenhouse gas emissions of agricultural products but are spatially and tempo-rally variable, due to complex interactions between climate, soil and management variables. This study aimed to identify the main factors that affect N2Oemissions under sugarcane, using a multi-site data-base from field experiments. Greenhouse gas fluxes, soil, climate, and management data were obtained from 13 field trials spanning the 2011â2017 period. We conducted exploratory, descriptive and inferential data analyses in experiments with varying fertiliser and stillage (vinasse) type and rate, and crop residue rates. The most relevant period of high N2O fluxes was the first 46 days after fertiliser application. The results indicate a strong positive correlation of cumulative N2O with nitrogen (N) fertiliser rate, soil fungi community (18S rRNA gene), soil ammonium(NH 4+ ) and nitrate (NO3â); and a moderate negative correlation with amoA genes of ammonia-oxidising archaea (AOA) and soil organic matter content. The regression analysis revealed that easily routinely measured climate and management-related variables explained over 50% of the variation in cumulativeN2O emissions, and that additional soil chemical and physical parameters improved the regression fit within R2 = 0.65. Cross-wavelet analysis indicated significant correlations of N2O fluxes with rainfall and air temperature up to 64 days, associated with temporal lags of 2 to 4 days in some experiments, and presenting a good environmental control over fluxes in general. The nitrogen fertiliser mean emission factors ranged from 0.03 to 1.17% of N applied, with urea and ammonium nitrate plus vinasse producing high emissions, while ammonium sulphate, ammonium nitrate without vinasse, calcium nitrate, and mitigation alternatives (nitrification inhibitors and timing of vinasse application) producing low N2O-EFs. Measurements from multiple sites spanning several crop-ping seasons were useful for exploring the influence of environmental and management-related variables on soil N 2O emissions in sugarcane production, providing support for global warming mitigation strategies, nitrogen management policies, and increased agricultural input efficiency
UHMWPE/HDPE in-reactor blends, prepared by in situ polymerization: synthetic aspects and characterization
This work covers the synthesis and characterization of in-reactor Ultra-High Molecular Weight Polyethylene/
High Density Polyethylene, UHMWPE/HDPE, blends by in situ polymerization in a single reactor, through dual catalyst
immobilization. These blends are synthesized combining two different catalysts (one for each targeted molar mass) co-immobilized
in mesoporous Santa Barbara Amorphous, SBA-15, particles. First, the ethylene polymerization behavior is investigated,
under different polymerization conditions. Then, studies on the thermal, mechanical and rheological characteristics
of the produced in-reactor blends are presented and their performance is compared and discussed in a comprehensive way.
Moreover, the effect of different filler contents on the properties exhibited by the resulting materials is investigated.
Results have shown that these in-reactor UHMWPE/HDPE blends exhibit a complex thermal, mechanical and rheological
behavior, which depends mainly on the proportion between the two polymer components and on the amount of SBA-15.info:eu-repo/semantics/publishedVersio
Rapidity Distributions of Dileptons from a Hadronizing Quark-Gluon Plasma
It has been predicted that dilepton production may be used as a quark-gluon
plasma probe. We calculate the rapidity distributions of thermal dileptons
produced by an evolving quark-gluon plasma assuming a longitudinal scaling
expansion with initial conditions locally determined from the hadronic rapidity
density. These distributions are compared with Drell-Yan production and
semileptonic charm decays at invariant mass , 4, and 6 GeV.Comment: 17 pages (standard LaTeX), 6 figures (available as topdraw files or
printed versions upon request), GSI-93-6
Hybrid Stars in a Strong Magnetic Field
We study the effects of high magnetic fields on the particle population and
equation of state of hybrid stars using an extended hadronic and quark SU(3)
non-linear realization of the sigma model. In this model the degrees of freedom
change naturally from hadrons to quarks as the density and/or temperature
increases. The effects of high magnetic fields and anomalous magnetic moment
are visible in the macroscopic properties of the star, such as mass, adiabatic
index, moment of inertia, and cooling curves. Moreover, at the same time that
the magnetic fields become high enough to modify those properties, they make
the star anisotropic.Comment: Revised version with updated reference
Heavy Quarkonium Physics
This report is the result of the collaboration and research effort of the
Quarkonium Working Group over the last three years. It provides a comprehensive
overview of the state of the art in heavy-quarkonium theory and experiment,
covering quarkonium spectroscopy, decay, and production, the determination of
QCD parameters from quarkonium observables, quarkonia in media, and the effects
on quarkonia of physics beyond the Standard Model. An introduction to common
theoretical and experimental tools is included. Future opportunities for
research in quarkonium physics are also discussed.Comment: xviii + 487 pages, 260 figures. The full text is also available at
the Quarkonium Working Group web page: http://www.qwg.to.infn.i
Percepção ambiental de docentes e discentes da rede de ensino pĂșblico superior do municĂpio de Parintins - CESP/ UEA.
As questĂ”es ambientais sĂŁo pautas das arenas de discussĂŁo locais e globais. Todos reconhecem que o nosso ambiente estĂĄ sendo devastado, pois sĂŁo constantes as notĂcias vinculadas na mĂdia falada e escrita sobre mudanças climĂĄticas, poluição de rios e do ar, destruição da floresta, extinção de espĂ©cies, esgotamento dos recursos minerais. A importĂąncia da pesquisa em percepção ambiental para o planejamento ambiental Ă© uma ação coordenada para minimizar estes impactos antrĂłpicos negativos gerados por nossas açÔes ao ambiente. "Uma das dificuldades para a proteção dos ecossistemas naturais estĂĄ na existĂȘncia de diferenças nas percepçÔes dos valores e da importĂąncia dos mesmos entre indivĂduos de culturas diferentes ou de grupos sĂłcio-econĂŽmicos que desempenham funçÔes, no plano social. Neste cenĂĄrio, caracterizar o conhecimento e a percepção ambiental dos atores envolvidos, docentes e discentes da rede de ensino pĂșblico (superior) do municĂpio de Parintins, instigando-os atravĂ©s de abordagem participativa na construção de estratĂ©gias e açÔes transformadoras, pode ajudar a clarear os passos a serem trilhados na expectativa de implantação de um programa de educação ambiental com começo, meio e fim
Vaccines against toxoplasma gondii : challenges and opportunities
Development of vaccines against Toxoplasma gondii infection in humans is of high priority, given the high burden of disease in some areas of the world like South America, and the lack of effective drugs with few adverse effects. Rodent models have been used in research on vaccines against T. gondii over the past decades. However, regardless of the vaccine construct, the vaccines have not been able to induce protective immunity when the organism is challenged with T. gondii, either directly or via a vector. Only a few live, attenuated T. gondii strains used for immunization have been able to confer protective immunity, which is measured by a lack of tissue cysts after challenge. Furthermore, challenge with low virulence strains, especially strains with genotype II, will probably be insufficient to provide protection against the more virulent T. gondii strains, such as those with genotypes I or II, or those genotypes from South America not belonging to genotype I, II or III. Future studies should use animal models besides rodents, and challenges should be performed with at least one genotype II T. gondii and one of the more virulent genotypes. Endpoints like maternal-foetal transmission and prevention of eye disease are important in addition to the traditional endpoint of survival or reduction in numbers of brain cysts after challenge
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