9,348 research outputs found
Study of psi' and chi_c decays as feed-down sources of J/psi hadro-production
The interpretation of the J/psi suppression patterns observed in nuclear
collisions, at CERN and RHIC, as a signature of the formation of a deconfined
phase of QCD matter, requires knowing which fractions of the measured J/psi
yields, in pp collisions, are due to decays of heavier charmonium states. From
a detailed analysis of the available mid-rapidity charmonium hadro-production
cross sections, or their ratios, we determine that the J/psi feed-down
contributions from psi' and chi_c decays are, respectively, (8.1 +/- 0.3) % and
(25 +/- 5) %. These proton-proton values are derived from global averages of
the proton-nucleus measurements, assuming that the charmonium states are
exponentially absorbed with the length of matter they traverse in the nuclear
targets.Comment: 12 pages, 4 figures, 3 table
From ‘creative cities’ to ‘urban creativity’? Space, creativity and governance in the contemporary city
DINÂMIA, Dezembro de 2009This paper derives from a broader research program studying the forms of governance associated with creative dynamics in cities (the “Creatcity” project) and draws on the first empirical results generated by the
study following analysis of a set of exploratory interviews involving actors central to thinking and acting on
the contemporary city (political decision makers, official structures and civil society) in the three
metropolitan areas selected for the project: Lisbon (Portugal), São Paulo (Brazil) and Barcelona (Spain).
Analysis of the responses sought to identify the different perspectives on the concepts of urban creativity and
creative city and the relationship between creativity, vitality and competitivity within urban contexts while seeking to understand interviewee perspectives on the structural conditions necessary for the development of
creativity in the city in terms of spatial/geographic configurations and the associated cultural ambiances and
economic activities. In parallel, we aim to debate the means of fostering and supporting creativity in urban environments and discuss just which strategic policies and governance processes best achieve this.FC
Heavy-ion Physics at a Fixed-Target Experiment Using the LHC Proton and Lead Beams (AFTER@LHC): Feasibility Studies for Quarkonium and Drell-Yan Production
We outline the case for heavy-ion-physics studies using the multi-TeV lead
LHC beams in the fixed-target mode. After a brief contextual reminder, we
detail the possible contributions of AFTER@LHC to heavy-ion physics with a
specific emphasis on quarkonia. We then present performance simulations for a
selection of observables. These show that , and
production in heavy-ion collisions can be studied in new energy and
rapidity domains with the LHCb and ALICE detectors. We also discuss the
relevance to analyse the Drell-Yan pair production in asymmetric
nucleus-nucleus collisions to study the factorisation of the nuclear
modification of partonic densities and of further quarkonia to restore their
status of golden probes of the quark-gluon plasma formation.Comment: 18 pages, 7 figure
Cambio climatico y plagas forestales: el caso de la procesionaria del pino en el noreste de Portugal
The pine processionary moth, Thaumetopoea pityocampa (Den. & Schiff.) (Lep., Thaumetopoeidae) is known as the most defoliating insect in Pinus and Cedrus in many countries. In the last three decades, climate change has led to a substantial expansion of its range and high attack rates in previously unaffected areas were observed. A 3-year analysis of the effect of several climatic elements on the T. pityocampa adult emergence was made and one climatic change scenario was tested in order to predict the insect’s behaviour in the future. Results showed that mean air temperature was the climatic element with the best single regression fit to adult emergence, whereas minimum air temperature and relative humidity provided the best multiple regression fits. Results also demonstrated that higher emergence of adults is often related to a maximum temperature above 30°C, a mean temperature above 23°C, a minimum temperature above 17°C, relative humidity lower than 60% and precipitation values lower than 10 mm. Using the same thresholds for future climatic conditions simulated by the COSMO-CLM model, the period for pine processionary moth emergence will be expanded, starting much sooner. Contrasting with the actual emergence period, the insect is projected to have favorable climatic conditions to start emerging in May. This might have serious implications in forest ecosystems, concerning not only ecological issues, but also forest management.La procesionaria del pino, Thaumetopoea pityocampa (Den. & Schiff.) (Lep., Thaumetopoeidae), es conocido en muchos
países como el insecto más defoliador de Pinus y Cedrus. En las últimas tres décadas el cambio climático ha originado
una considerable expansión de su rango de distribución y aumentado la proporción de ataques en áreas previamente
no atacadas. Durante tres años fue realizada una monitorización de los efectos de diversos elementos climáticos sobre
la emergencia de los adultos de T. pityocampa y un escenario de cambio climático fue testado con el fin de predecir el
comportamiento de los insectos en el futuro. Los resultados revelan que la temperatura media del aire es el elemento climático
que más contribuye en la regresión simple para explicar la emergencia de adultos, seguidos de la temperatura mínima
del aire y la humedad relativa. Nuestros resultados también demostraron que el aumento de emergencia de adultos
estaba a menudo relacionado con temperaturas máximas superiores a 30°C, temperatura media por encima de los 23°C,
temperatura mínima por encima de 17°C, humedad relativa inferior al 60% y valores de precipitación inferiores a los 10
mm. Atendiendo a los resultados para eses umbrales climáticos y el modelo de CLM, el periodo de emergencia de la procesionaria
de pino se extenderá, comenzando mucho antes. En contraste con el actual periodo de emergencia, el insecto
tendrá condiciones climáticas favorables para comenzar a emerger en Mayo. Esto tendrá consecuencias graves para los
ecosistemas forestales no sólo al nivel de las cuestiones ecológicas, sino también para la gestión forestal
Factorial Moments in a Generalized Lattice Gas Model
We construct a simple multicomponent lattice gas model in one dimension in
which each site can either be empty or occupied by at most one particle of any
one of species. Particles interact with a nearest neighbor interaction
which depends on the species involved. This model is capable of reproducing the
relations between factorial moments observed in high--energy scattering
experiments for moderate values of . The factorial moments of the negative
binomial distribution can be obtained exactly in the limit as becomes
large, and two suitable prescriptions involving randomly drawn nearest neighbor
interactions are given. These results indicate the need for considerable care
in any attempt to extract information regarding possible critical phenomena
from empirical factorial moments.Comment: 15 pages + 1 figure (appended as postscript file), REVTEX 3.0,
NORDITA preprint 93/4
First record of the Hauxwell's Thrush, Turdus hauxwelli Lawrence, 1869 (Aves: Turdidae) from Mato Grosso do Sul, Brazil, and geographic range extension
We report the first record of the Hauxwell’s Thrush, Turdus hauxwelli Lawrence, 1869 (Aves: Turdidae) in the state of Mato Grosso do Sul, Brazil. During an ornithological inventory conducted in Serra de Maracajú, municipality of Corguinho, we mist-netted and collected an individual of the species. The specimen was prepared as study skin and is held in the ornithological collection of the Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro. This record is located 472 km south of the closest visual/song record and 616 km southeast of the closest museum specimen, being the southernmost occurrence of this thrush
Uso e manejo de leguminosas em agroecossistemas na Amazônia Central.
Este estudo teve como objetivo gerar informações que poderão auxiliar os fruticultores da região na tomada de decisão quanto ao uso e manejo de leguminosas, como tefrósia, para inserção em sistemas de produção de fruteiras, visando à melhoria e manutenção da capacidade produtiva do solo, o controle de invasoras e o desenvolvimento e a produtividade das plantas
Insights into the transcriptional regulation of poorly characterized alcohol acetyltransferase-encoding genes (HgAATs) shed light into the production of acetate esters in the wine yeast Hanseniaspora guilliermondii
Hanseniaspora guilliermondii is a well-recognized producer of acetate esters associated with fruity and floral aromas. The molecular mechanisms underneath this production or the environmental factors modulating it remain unknown. Herein, we found that, unlike Saccharomyces cerevisiae, H. guilliermondii over-produces acetate esters and higher alcohols at low carbon-to-assimilable nitrogen (C:N) ratios, with the highest titers being obtained in the amino acid-enriched medium YPD. The evidences gathered support a model in which the strict preference of H. guilliermondii for amino acids as nitrogen sources results in a channeling of keto-acids obtained after transamination to higher alcohols and acetate esters. This higher production was accompanied by higher expression of the four HgAATs, genes, recently proposed to encode alcohol acetyl transferases. In silico analyses of these HgAat's reveal that they harbor conserved AATs motifs, albeit radical substitutions were identified that might result in different kinetic properties. Close homologues of HgAat2, HgAat3, and HgAat4 were only found in members of Hanseniaspora genus and phylogenetic reconstruction shows that these constitute a distinct family of Aat's. These results advance the exploration of H. guilliermondii as a bio-flavoring agent providing important insights to guide future strategies for strain engineering and media manipulation that can enhance production of aromatic volatiles.info:eu-repo/semantics/publishedVersio
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