22 research outputs found

    A construção do mercado para o café em Alto Paraíso de Goiás.

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    Este estudo apresenta os principais resultados da análise de como habitantes de Alto Paraíso de Goiás estão buscando alternativas para o desenvolvimento sustentável do município, por meio da implantação, pela Embrapa, de projeto relativo ao resgate do café. A mineração e as atividades agropecuárias foram exercidas na região até os anos 60, quando a atividade principal passou a ser o turismo, a partir da criação do Parque Nacional da Chapada dos Veadeiros e da inauguração de Brasília. Em 2000, o fluxo de turistas decaiu devido a problemas relativos à saúde pública, acarretando estagnação da economia local. Nos últimos anos, produtores familiares despertaram para a existência, ali, de um café que pode ser comercializado em nichos de mercado de grãos especiais: orgânicos e de origem definida, e buscaram, na Embrapa, o desenvolvimento de projeto de pesquisa. O estudo na região revelou que por meio do desvelamento de valores - história, cultura e tradições - é possível estabelecer estratégia mais eficiente de busca de mercado, a partir da experiência revelada no trabalho concreto e na cultura dos produtores. E que o desenvolvimento rural deve ser buscado por meio do desenvolvimento de atividades da nova ruralidade e da aplicação de abordagem territorial de desenvolvimento

    The enzymatic basis for pesticide bioremediation

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    Enzymes are central to the biology of many pesticides, influencing their modes of action, environmental fates and mechanisms of target species resistance. Since the introduction of synthetic xenobiotic pesticides, enzymes responsible for pesticide turnover have evolved rapidly, in both the target organisms and incidentally exposed biota. Such enzymes are a source of significant biotechnological potential and form the basis of several bioremediation strategies intended to reduce the environmental impacts of pesticide residues. This review describes examples of enzymes possessing the major activities employed in the bioremediation of pesticide residues, and some of the strategies by which they are employed. In addition, several examples of specific achievements in enzyme engineering are considered, highlighting the growing trend in tailoring enzymatic activity to a specific biotechnologically relevant function

    First measurement of <math><msubsup><mi mathvariant="normal">Λ</mi><mrow><mi>c</mi></mrow><mo>+</mo></msubsup></math> production down to <math><mrow><msub><mi>p</mi><mi>T</mi></msub><mo>=</mo><mn>0</mn></mrow></math> in <math><mrow><mi>p</mi><mi>p</mi></mrow></math> and <math><mi>p</mi></math>-Pb collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> TeV

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    International audienceThe production of prompt Λc+ baryons has been measured at midrapidity in the transverse momentum interval 0&lt;pT&lt;1 GeV/c for the first time, in pp and p–Pb collisions at a center-of-mass energy per nucleon-nucleon collision sNN=5.02TeV. The measurement was performed in the decay channel Λc+→pKS0 by applying new decay reconstruction techniques using a Kalman-Filter vertexing algorithm and adopting a machine-learning approach for the candidate selection. The pT-integrated Λc+ production cross sections in both collision systems were determined and used along with the measured yields in Pb–Pb collisions to compute the pT-integrated nuclear modification factors RpPb and RAA of Λc+ baryons, which are compared to model calculations that consider nuclear modification of the parton distribution functions. The Λc+/D0 baryon-to-meson yield ratio is reported for pp and p–Pb collisions. Comparisons with models that include modified hadronization processes are presented, and the implications of the results on the understanding of charm hadronization in hadronic collisions are discussed. A significant (3.7σ) modification of the mean transverse momentum of Λc+ baryons is seen in p–Pb collisions with respect to pp collisions, while the pT-integrated Λc+/D0 yield ratio was found to be consistent between the two collision systems within the uncertainties

    Light (anti)nuclei production in Pb-Pb collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn><mo> </mo><mi>TeV</mi></mrow></math>

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    International audienceThe measurement of the production of deuterons, tritons and He3 and their antiparticles in Pb-Pb collisions at sNN=5.02TeV is presented in this article. The measurements are carried out at midrapidity (|y|&lt; 0.5) as a function of collision centrality using the ALICE detector. The pT-integrated yields, the coalescence parameters and the ratios to protons and antiprotons are reported and compared with nucleosynthesis models. The comparison of these results in different collision systems at different center-of-mass collision energies reveals a suppression of nucleus production in small systems. In the Statistical Hadronisation Model framework, this can be explained by a small correlation volume where the baryon number is conserved, as already shown in previous fluctuation analyses. However, a different size of the correlation volume is required to describe the proton yields in the same data sets. The coalescence model can describe this suppression by the fact that the wave functions of the nuclei are large and the fireball size starts to become comparable and even much smaller than the actual nucleus at low multiplicities

    Exclusive and dissociative <math display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> photoproduction, and exclusive dimuon production, in p-Pb collisions at <math display="inline"><mrow><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>NN</mi></mrow></msub></mrow></msqrt><mo>=</mo><mn>8.16</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math>

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    International audienceThe ALICE Collaboration reports three measurements in ultraperipheral proton-lead collisions at forward rapidity. The exclusive two-photon process γγ→μ+μ- and the exclusive photoproduction of J/ψ are studied. J/ψ photoproduction with proton dissociation is measured for the first time at a hadron collider. The cross section for the two-photon process of dimuons in the invariant mass range from 1 to 2.5  GeV/c2 agrees with leading-order quantum electrodynamics calculations. The exclusive and dissociative cross sections for J/ψ photoproductions are measured for photon-proton center-of-mass energies from 27 to 57 GeV. They are in good agreement with HERA results

    Symmetry plane correlations in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76TeV

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    International audienceA newly developed observable for correlations between symmetry planes, which characterize the direction of the anisotropic emission of produced particles, is measured in Pb–Pb collisions at sNN\sqrt{s_\text {NN}} = 2.76 TeV with ALICE. This so-called Gaussian Estimator allows for the first time the study of these quantities without the influence of correlations between different flow amplitudes. The centrality dependence of various correlations between two, three and four symmetry planes is presented. The ordering of magnitude between these symmetry plane correlations is discussed and the results of the Gaussian Estimator are compared with measurements of previously used estimators. The results utilizing the new estimator lead to significantly smaller correlations than reported by studies using the Scalar Product method. Furthermore, the obtained symmetry plane correlations are compared to state-of-the-art hydrodynamic model calculations for the evolution of heavy-ion collisions. While the model predictions provide a qualitative description of the data, quantitative agreement is not always observed, particularly for correlators with significant non-linear response of the medium to initial state anisotropies of the collision system. As these results provide unique and independent information, their usage in future Bayesian analysis can further constrain our knowledge on the properties of the QCD matter produced in ultrarelativistic heavy-ion collisions

    Accessing the strong interaction between Λ baryons and charged kaons with the femtoscopy technique at the LHC

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    The interaction between Λ baryons and kaons/antikaons is a crucial ingredient for the strangeness S=0 and S=−2 sector of the meson–baryon interaction at low energies. In particular, the ΛK‾ might help in understanding the origin of states such as the Ξ(1620), whose nature and properties are still under debate. Experimental data on Λ–K and Λ–K‾ systems are scarce, leading to large uncertainties and tension between the available theoretical predictions constrained by such data. In this Letter we present the measurements of Λ–K⊕+Λ‾–K− and Λ–K⊕−Λ‾–K+ correlations obtained in the high-multiplicity triggered data sample in pp collisions at s=13 TeV recorded by ALICE at the LHC. The correlation function for both pairs is modeled using the Lednický–Lyuboshits analytical formula and the corresponding scattering parameters are extracted. The Λ–K⊕−Λ‾–K+ correlations show the presence of several structures at relative momenta k⁎ above 200 MeV/c, compatible with the Ω baryon, the Ξ(1690), and Ξ(1820) resonances decaying into Λ–K− pairs. The low k⁎ region in the Λ–K⊕−Λ‾–K+ also exhibits the presence of the Ξ(1620) state, expected to strongly couple to the measured pair. The presented data allow to access the ΛK+ and ΛK− strong interaction with an unprecedented precision and deliver the first experimental observation of the Ξ(1620) decaying into ΛK−

    Production of pions, kaons, and protons as a function of the relative transverse activity classifier in pp collisions at s \sqrt{s} = 13 TeV

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    International audienceThe production of π±^{±}, K±^{±}, and (p)p \left(\overline{\textrm{p}}\right)\textrm{p} is measured in pp collisions at s \sqrt{s} = 13 TeV in different topological regions of the events. Particle transverse momentum (pT_{T}) spectra are measured in the “toward”, “transverse”, and “away” angular regions defined with respect to the direction of the leading particle in the event. While the toward and away regions contain the fragmentation products of the near-side and away-side jets, respectively, the transverse region is dominated by particles from the Underlying Event (UE). The relative transverse activity classifier, RT_{T} = NT_{T}/〈NT_{T}〉, is used to group events according to their UE activity, where NT_{T} is the measured charged-particle multiplicity per event in the transverse region and 〈NT_{T}〉 is the mean value over all the analysed events. The first measurements of identified particle pT_{T} spectra as a function of RT_{T} in the three topological regions are reported. It is found that the yield of high transverse momentum particles relative to the RT_{T}-integrated measurement decreases with increasing RT_{T} in both the toward and the away regions, indicating that the softer UE dominates particle production as RT_{T} increases and validating that RT_{T} can be used to control the magnitude of the UE. Conversely, the spectral shapes in the transverse region harden significantly with increasing RT_{T}. This hardening follows a mass ordering, being more significant for heavier particles. Finally, it is observed that the pT_{T}-differential particle ratios \left(\textrm{p}+\overline{\textrm{p}}\right)/\left({\uppi}^{+}+{\uppi}^{-}\right) and (K+^{+} + K^{−})/(π+^{+} + π^{−}) in the low UE limit (RT_{T} → 0) approach expectations from Monte Carlo generators such as PYTHIA 8 with Monash 2013 tune and EPOS LHC, where the jet-fragmentation models have been tuned to reproduce e+^{+}e^{−} results.[graphic not available: see fulltext

    Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at √ s = 5.02 and 13 TeV

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    The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of √s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within 0.8pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|2GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at √s=13TeV.

    Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at <math display="inline"><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> and 13 TeV

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    International audienceThe pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2  GeV/c is measured in pp collisions at the center of mass energies of s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within ±0.8 and pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|&lt;1 in pp collisions at s=5.02  TeV for the first time at the LHC. These measurements are compared to the pythia 6, pythia 8, and epos-lhc models. In general, the models describe the η dependence of particle production well. However, discrepancies are observed for the highest transverse momentum threshold (pT&gt;2  GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at s=13  TeV
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