413 research outputs found
Evolução da produção e do mercado mundial do feijão.
Realizou-se uma avaliação do mercado internacional de feijão, considerando produção, exportação e importação, mostrando o comportamento e oscilações dos principais países
Design, Synthesis and Catalytic Activity of (Cyclopentadienone)iron Complexes Containing a Stereogenic Plane and a Stereogenic Axis
Herein, we report the synthesis and characterization of several chiral (cyclopentadienone)iron complexes (CICs) featuring either two (R)-BINOL-derived stereoaxes or a combination of one (R)-BINOL-derived stereoaxis and a stereogenic plane. The stereoplane-containing CICs were obtained as epimer mixtures, which were separated by flash column chromatography and assigned an absolute configuration based on XRD analysis, NMR and order of elution. The library was tested in the asymmetric hydrogenation of ketones showing good catalytic activity and a moderate stereoselectivity which, notably, is mostly imparted by the stereogenic plane. Indeed, the two epimers of each CIC possessing a stereoplane show opposite and equally strong stereochemical preference.Winning plane: chiral (cyclopentadienone)iron complexes (CICs) featuring a combination of an (R)-BINOL-derived stereoaxis and a stereogenic plane were synthesized in diastereoisomerically pure form, characterized and tested in the asymmetric hydrogenation of ketones. The new CICs showed good catalytic activity and, remarkably, the stereoplane epimers displayed similar and opposite stereochemical preference
I clienti invadenti. Nuove relazioni di mercato tra clienti e imprese / Invading customers. New Markets relationships
Measuring diversity in multilingual communication
This article develops new indices to measure linguistic diversity. It is new in two respects: firstly, existing indices to measure the probability that in a given multilingual context communication among people speaking different languages can successfully occur are based on the assumption that communication is possible only if at least one single language is shared. This study develops new indices that describe the probability that people with different linguistic repertoires can effectively communicate not only through one common language, but also by relying on their receptive competence in multiple languages, or a mix between the two communication strategies. Secondly, it develops indices to measure the degree of diversity of language policies aimed at providing multilingual communication (through translation and interpretation). The focus, therefore, is on the organisation as collective actors rather than individuals. The indices may be relevant to the study of the political and economic implications of linguistic diversity in multilingual countries, and in the management of diversity in multilingual organisations
Does higher sampling rate (multiband + SENSE) improve group statistics - An example from social neuroscience block design at 3T
Grupos de desenvolvimento humano: uma proposta para a promoção da auto-análise e autogestão na Embrapa Soja.
Naturalness and theoretical constraints on the Higgs boson mass
Arbitrary regularization dependent parameters in Quantum Field Theory are
usually fixed on symmetry or phenomenology grounds. We verify that the
quadratically divergent behavior responsible for the lack of naturalness in the
Standard Model (SM) is intrinsically arbitrary and regularization dependent.
While quadratic divergences are welcome for instance in effective models of low
energy QCD, they pose a problem in the SM treated as an effective theory in the
Higgs sector. Being the very existence of quadratic divergences a matter of
debate, a plausible scenario is to search for a symmetry requirement that could
fix the arbitrary coefficient of the leading quadratic behavior to the Higgs
boson mass to zero. We show that this is possible employing consistency of
scale symmetry breaking by quantum corrections. Besides eliminating a
fine-tuning problem and restoring validity of perturbation theory, this
requirement allows to construct bounds for the Higgs boson mass in terms of
(where is the renormalized Higgs mass and
is the 1-loop Higgs mass correction). Whereas
(perturbative regime) in this scenario allows the Higgs boson mass around the
current accepted value, the inclusion of the quadratic divergence demands
arbitrarily large to reach that experimental value.Comment: 6 pages, 4 figure
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