Uncertainty Characterization Of A Conceptual Rainfall-Runoff Model By Using Grey Numbers

A procedure for characterizing global uncertainty of a rainfall-runoff simulation model based on using grey numbers is presented. By using the grey numbers technique the uncertainty is characterized by an interval; once the parameters of the rainfall-runoff model have been properly defined as grey numbers, by using the grey mathematics and functions it is possible to obtain simulated discharges in the form of grey numbers whose envelope defines a band which represents the vagueness/uncertainty associated with the simulated variable. The grey numbers representing the model parameters are estimated in such a way that the band obtained from the envelope of simulated grey discharges includes an assigned percentage of observed discharge values and is at the same time as narrow as possible. The approach is applied to a real case study highlighting that a rigorous application of the procedure for direct simulation through the rainfall-runoff model with grey parameters involves long computational times. However, these times can be significantly reduced using a simplified computing procedure with minimal approximations in the quantification of the grey numbers representing the simulated discharges. Relying on this simplified procedure, the conceptual rainfall-runoff grey model is thus calibrated and the uncertainty bands obtained both downstream of the calibration process and downstream of the validation process are compared with those obtained by using a well-established approach, like the GLUE approach, for characterizing uncertainty. The results of the comparison show that the proposed approach may represent a valid tool for characterizing the global uncertainty associable with the output of a rainfall-runoff simulation model.

Trade and poverty in latin american countries: conceptual and methodological challenges

This paper addresses topics - either relevant or confusing or needing more attention - related to measuring the trade and poverty nexus. It sheds a critical light on the existing material and suggests needed research lines. It starts with questions akin to the LAC realities; then, keeping this view, general methodological issues are also examined. In a broader perspective, further ideas for the research agenda are formulated. The main conclusion is that relevant findings still demand considerable efforts. Moreover, the Information-measurement-model-evaluation paradigm is not enough, policy guidelines being usually too general. In LAC, it must be extended and deepened, accounting more for the heterogeneity of cases, including, whenever possible, the physical constraints and incorporating new ways of integrating both the local and global perspectives. Other aspects, like the role of specific juridical measures, should play a role. How all this can be combined into more encompassing evaluations remains open

Do empirismo para a ciência, na procura da eficiência conceptual e metodológica no treino da capoeira

Na actual conjuntura de crise, é necessária a emergência de um paradigma mais rentável e que analise os fenómenos na sua globalidade, mantendo a coerência do todo. Utilizando o desporto, mais concretamente a capoeira, pretende-se promover a desejada transformação do Homem de forma intencional e eficiente, através da rentabilização da modalidade quer nos seus objectivos imediatos quer mediatos. A generalidade do conhecimento sobre capoeira é baseado e veiculado sob a forma empírica, o que se reflecte no processo de operacionalização da modalidade. Procura-se então, iniciar a ruptura com o empirismo, através da aplicação de ferramentas já testadas, nomeadamente o Modelo de Desportos de Combate da taxonomia de Almada (1994), que permite desdobrar as variáveis básicas de movimento e identificar quais as que podem ser tratadas de forma rentável. Recorrendo a um elemento técnico da capoeira – a meia-lua de compasso –, procurou-se verificar se a análise realizada através do modelo poderia ser útil. Realizaram-se duas situações experimentais, de análise videográfica, que permitem conhecer os limites temporais sobre os quais a acção se pode dar, utilizando para a situação 1 uma amostra de n=13 capoeiristas, e para a situação 2 duas amostras de n1=12 capoeiristas de nível iniciado-intermédio, e n2=8 capoeiristas de nível avançado. Verificou-se, assim, que através da utilização do referido modelo, é possível identificar variáveis fundamentais para a compreensão do fenómeno e de limites a respeitar.

A (re)significação conceptual nas práticas colaborativas com professores do Ensino Fundamental

The work objectified to apprehend the degree of the teachers' concept concerning the territory concept and to intervene with situations of critical reflections to accompany and to analyze the process of conceptual elaboration. It contemplates on the (new)meaning of knowledge and (new)elaboration of the concept in study done inside a pedagogic intervention. The Municipal School Dr. Julio Senna - Ceará-Mirim/RN and six (6) teacher-collaborators that taught in the 3rd and 4th grades of the fundamental teaching, constitutes the empiric field of the research. Its theoretical-methodological contributions are built in the studies of Vigotski (2000a, 2000b and 2001) on the formation process and development of concepts; in the methodology colaborate (Ibiapina (2004), Bartomé (1986), Kemmis and Mctaggart (1988), Arnal, Del Ricon and Latorre (1992), Pepper and Ghedin (2002), among others) and in the critical-reflexive conception of the Geography (Soares Júnior (2000 and 1994), Silva (1998), Raffestin (1993), Santos (1994), Felipe (1998), among others). The accomplishment of the work presupposed starting from the reflections on the following subjects: which the teachers' understanding in the school space concerning the territory concept? How does happen the process of conceptual construction territory for the teachers? The analysis of the teachers' previous knowledge on the concept in study, evidenced that its apprehensions on the attributes of the referred concept went mentioned the to light of the perceptible dimension of the real-concrete relationships of the reality linked to the degree of the spontaneous concepts and followed by the ideas of the traditional, humanistic and cultural geographical conceptions (positivism and phenomenology), restricting the territory meaning the notion of State-Nation and place of the men's dwelling. In the intervention process, it was verified to real possibility of the acquisition of indispensable scientific concepts to the process of (new)meaning conceptual of geographical knowledge through the continuous practice of the educational formation, when it was evidenced that the teacher-collaborators acquired high degrees of attributions of the significance of the territory concept to the they elaborate generalizations by means of analyses and syntheses of the concept-attribute (essential and multiples) of the reference conceptual in study

DFT study of alpha-alanine as a function of the medium polarity

The zwitterionic (Z) form, neutral (N) form and transition structure (TS) connecting N to Z, have been studied at the B3LYP/6-31++G** level of calculation by using the SCRF methodology. The intramolecular proton transfer from oxygen to nitrogen atoms of alpha -alanine and vibrational spectrum were analyzed in the different environments employed: acetonitrile, ethanol, carbon tetrachloride and gas phase. The Z species is a stationary point in acetonitrile and ethanol, but not in carbon tetrachloride and gas phase media. The geometry of N, Z and TS was similar in acetonitrile and ethanol. The vibrational spectrum of Z was similar in the two solvents studied. (C) 2001 Elsevier B.V. B.V. All lights reserved.

DFT study of the water-assisted tautomerization process between hydrated oxide, MO(H2O)(+), and dihydroxide, M(OH)(2)(+) cations (M = V, Nb and Ta)

Density functional theory (DFT) calculations point out that the participation of water can effectively lower the barrier height for the isomerization process between hydrated oxide cation, MO(H2O)(+), and dihydroxide cation, M(OH)(2)(+), (M = V, Nb and Ta). The catalytic effect is achieved by a water-assisted mechanism in which water acts as proton donor and acceptor, via a transition structure corresponding to a six-membered ring. In the case of vanadium atom, the presence of two water molecules has been taken into account and the tautomerization becomes nearly barrierless, decreasing both the stability of the transition structures relative to intermediates and the depths of wells associated with the intermediates. (C) 2003 Elsevier B.V. All rights reserved.

Fully Relativistic 4-Components DFT Investigation on Bonding and Dissociation Energy of HgO

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo teórico QTAIM e DFT dos compostos de coordenação: efeito quelato, titanocenos e ligação química

This work is a study of coordination compounds by quantum theory of atoms in molecules (QTAIM), based on the topological analysis of the electron density of molecular systems, both theoretically and experimentally obtained. The coordination chemistry topics which were studied are the chelate effect, bent titanocene and chemical bond in coordination complexes. The chelate effect was investigated according to topological and thermodynamic parameters. The exchange of monodentate ligands on polydentate ligands from same transition metal increases the stability of the complex both from entropy and enthalpy contributions. In some cases, the latter had a higher contribution to the stability of the complex in comparison with entropy. This enthalpic contribution is explained according to topological analysis of the M-ligand bonds where polidentate complex had higher values of electron density of bond critical point, Laplacian of electron density of bond critical point and delocalization index (number of shared electrons between two atoms). In the second chapter, was studied bent titanocenes with bulky cyclopentadienyl derivative π-ligand. The topological study showed the presence of secondary interactions between the atoms of π-ligands or between atoms of π-ligand and -ligand. It was found that, in the case of titanocenes with small difference in point group symmetry and with bulky ligands, there was an nearly linear relationship between stability and delocalization index involving the ring carbon atoms (Cp) and the titanium. However, the titanocene stability is not only related to the interaction between Ti and C atoms of Cp ring, but secondary interactions also play important role on the stability of voluminous titanocenes. The third chapter deals with the chemical bond in coordination compounds by means of QTAIM. The quantum theory of atoms in molecules so far classifies bonds and chemical interactions in two categories: closed shell interaction (ionic bond, hydrogen bond, van der Waals interaction, etc) and shared interaction (covalent bond). Based on topological parameters such as electron density, Laplacian of electron density, delocalization index, among others, was classified the chemical bond in coordination compounds as an intermediate between closed shell and shared interactions

Archival information and organic information: a conceptual analysis of the Brazilian literature

Information has increasingly become a crucial resource for organizations that want to remain competitive in the market. For this reason, analysis and a correct understanding of informational types that are present in these environments become relevant to achieving the highest levels of performance. The aim of this paper is to review the literature of the concepts of organic and archival information within the organizational context/business environments. This is still an emerging theoretical field and therefore is conducive to intense discussions. We point out elements that help to characterize and distinguish these two types of information.

Bronsted Acid Catalyzed Morita-Baylis-Hillman Reaction: A New Mechanistic View for Thioureas Revealed by ESI-MS(/MS) Monitoring and DFT Calculations

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Molecular structures and vibrational frequencies for [PdX2(tdmPz)] (X = Cl-, SCN-): A DFT study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Synthesis, characterization, thermal studies, and DFT calculations on Pd(II) complexes containing N-methylbenzylamine

This work describes the synthesis, characterization, and the thermal behavior investigation of four palladium(II) complexes with general formulae [PdX(2)(mba)(2)], in which mba = N-methylbenzylamine and X = OAc(-) (1), Cl(-) (2), Br(-) (3) or I(-) (4). The complexes were characterized by elemental analysis, infrared vibrational spectroscopy, and (1)H nuclear magnetic resonance. The stoichiometry of the complexes was established by means of elemental analysis and thermogravimetry (TG). TG/DTA curves showed that the thermodecomposition of the four complexes occurred in 3-4 steps, leading to metallic palladium as final residue. The palladium content found in all curves was in agreement with the mass percentages calculated for the complexes. The following thermal stability sequence was found: 3 > 2 > 4 > 1. The geometry optimization of 1, 2, 3, and 4, calculated using the DFT/B3LYP method, yielded a slightly distorted square planar environment around the Pd(II) ion made by two anionic groups and two nitrogen atoms from the mba ligand (N1 and N2), in a trans-relationship.

Antioxidant Properties of Plant Extracts: an EPR and DFT Comparative Study of the Reaction with DPPH, TEMPOL and Spin Trap DMPO

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Absolute configuration reassignment of two chromanes from Peperomia obtusifolia (Piperaceae) using VCD and DFT calculations

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)