280 research outputs found

    Mozambique's Future: Modeling Population and Sustainable Development Challenges

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    What are the prospects for sustainable development over the next 20 years in Mozambique? Although it looks as if much of the development prospects are determined by such inherently unpredictable events as war, peace, and weather calamities, there are also many changes and patterns which have a long-term stability and which change only slowly over time. For example, socio-demographic changes, such as labor force skills, and population health have a long momentum. These are very important indicators for the economic development potential of a country. Also, although it is impossible to predict a particular year of heavy rains or droughts, there are long time series of weather from which we can calculate the country's vulnerability to single- or multiple-year weather disasters. To focus our efforts in answering this bold question, we concentrate on four issues: (1) Can poverty be erased in the next 20 years? (2) How will school enrollment lead to higher skills in the labor force by 2020? (3) What role will water play in development, in particular, water provision by rain to rural areas, and infrastructure to cities? (4) And, most importantly, what will be the impacts of the HIV/AIDS pandemic in the next decades

    Bosonic String and String Field Theory: a solution using Ultradistributions of Exponential Type

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    In this paper we show that Ultradistributions of Exponential Type (UET) are appropriate for the description in a consistent way string and string field theories. A new Lagrangian for the closed string is obtained and shown to be equivalent to Nambu-Goto's Lagrangian. We also show that the string field is a linear superposition of UET of compact support CUET). We evaluate the propagator for the string field, and calculate the convolution of two of them.Comment: 30 page

    Total Mass TCI driven by Parametric Estimation

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    This paper presents the Total Mass Target Controlled Infusion algorithm. The system comprises an On Line tuned Algorithm for Recovery Detection (OLARD) after an initial bolus administration and a Bayesian identification method for parametric estimation based on sparse measurements of the accessible signal. To design the drug dosage profile, two algorithms are here proposed. During the transient phase, an Input Variance Control (IVC) algorithm is used. It is based on the concept of TCI and aims to steer the drug effect to a predefined target value within an a priori fixed interval of time. After the steady state phase is reached the drug dose regimen is controlled by a Total Mass Control (TMC) algorithm. The mass control law for compartmental systems is robust even in the presence of parameter uncertainties. The whole system feasibility has been evaluated for the case of Neuromuscular Blockade (NMB) level and was tested both in simulation and in real cases

    Wetting evaluation of a refractory castable matrix (Al2O3-SiC-SiO2-C) by synthetic slags containing different amounts of MgO

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    O comportamento de espalhamento de quatro escórias sintéticas foi investigado pelo método da gota séssil, quando em contato com a matriz de um concreto refratário contendo alto teor de carbono e carbeto de boro como agente antioxidante. A evolução do molhamento do sólido foi monitorada a 1450, 1550 e 1650 ºC por 1800 s. Além disso, simulações termodinâmicas foram efetuadas, usando o programa FactSage®, visando promover um maior entendimento das reações químicas que podem ocorrer na interface dos materiais avaliados. Foi observado que a composição química do líquido afetou diretamente o espalhamento deste e quanto maior o teor de MgO na composição da escória, maiores foram os valores do ângulo de contato entre líquido e sólido. No entanto, em altas temperaturas e tempos prolongados, foram verificadas a formação de bolhas na superfície do líquido e a infiltração das escórias nos poros do refratário. Estes fatores afetaram negativamente e tornaram menos conclusivos os dados coletados nos ensaios propostos, apontando que ainda são necessários aperfeiçoamentos da técnica de molhabilidade para a avaliação de materiais complexos, tais como os concretos refratários

    A direct proof of Jauregui-Tsallis' conjecture

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    We give here direct proof of a recent conjecture of Jauregui and Tsallis about a new representation of Dirac's delta distribution by means of q-exponentials. The proof is based in the use of tempered ultradistributions' theory.Comment: 19 pages, no figure

    Modulation of subventricular zone oligodendrogenesis: a role for hemopressin?

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    Neural stem cells (NSCs) from the subventricular zone (SVZ) have been indicated as a source of new oligodendrocytes to use in regenerative medicine for myelin pathologies. Indeed, NSCs are multipotent cells that can self-renew and differentiate into all neural cell types of the central nervous system. In normal conditions, SVZ cells are poorly oligodendrogenic, nevertheless their oligodendrogenic potential is boosted following demyelination. Importantly, progressive restriction into the oligodendrocyte fate is specified by extrinsic and intrinsic factors, endocannabinoids being one of these factors. Although a role for endocannabinoids in oligodendrogenesis has already been foreseen, selective agonists and antagonists of cannabinoids receptors produce severe adverse side effects. Herein, we show that hemopressin (Hp),a modulator of CB1 receptors, increased oligodendroglial differentiation in SVZ neural stem/progenitor cell cultures derived from neonatal mice. The original results presented in this work suggest that Hp and derivates may be of potential interest for the development of future strategies to treat demyelinating diseases

    Understanding chemical reactions of CO2 and its isoelectronic molecules with 1-butyl-3-methylimidazolium acetate by changing the nature of the cation: The case of CS2 in 1-butyl-1-methylpyrrolidinium acetate studied by NMR spectroscopy and density functional theory calculations

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    NMR spectroscopy (H-1, C-13, N-15) shows that carbon disulfide reacts spontaneously with 1-butyl-1-methylpyrrolidinium acetate ([BmPyrro][Ac]) in the liquid phase. It is found that the acetate anions play an important role in conditioning chemical reactions with CS2 leading, via coupled complex reactions, to the degradation of this molecule to form thioacetate anion (CH3COS-), CO2, OCS, and trithiocarbonate (CS32-). In marked contrast, the cation does not lead to the formation of any adducts allowing to conclude that, at most, its role consists in assisting indirectly these reactions. The choice of the [BmPyrro](+) cation in the present study allows disentangling the role of the anion and the cation in the reactions. As a consequence, the ensemble of results already reported on CS2-[Bmim][Ac] (1), OCS-[Bmim][Ac] (2), and CO2-[Bmim][Ac] (3) systems can be consistently rationalized. It is argued that in system (1) both anion and cation play a role. The CS2 reacts with the acetate anion leading to the formation of CH3COS-, CO2, and OCS. After these reactions have proceeded the nascent CO2 and OCS interact with the cation to form imidazolium-carboxylate ([Bmim] CO2) and imidazolium-thiocarboxylate ([Bmim] COS). The same scenario also applies to system (2). In contrast, in the CO2-[Bmim] [Ac] system a concerted cooperative process between the cation, the anion, and the CO2 molecule takes place. A carbene issued from the cation reacts to form the [Bmim] CO2, whereas the proton released by the ring interacts with the anion to produce acetic acid. In all these systems, the formation of adduct resulting from the reaction between the solute molecule and the carbene species originating from the cation is expected. However, this species was only observed in systems (2) and (3). The absence of such an adduct in system (1) has been theoretically investigated using DFT calculations. The values of the energetic barrier of the reactions show that the formation of [Bmim] CS2 is unfavoured and that the anion offers a competitive reactive channel via an oxygen-sulphur exchange mechanism with the solute in systems (1) and (2). (C) 2014 AIP Publishing LLC

    Intercomparison Study of Six HTDMAs: Results and Recommendations

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    We report on an intercomparison of six different hygroscopicity tandem differential mobility analysers (HTDMAs). These HTDMAs are used worldwide in laboratory experiments and field campaigns to measure the water uptake of aerosol particles and have never been intercompared. After an investigation of the different design of the instruments with their advantages and inconveniencies, the methods for calibration, validation and data analysis are presented. Measurements of nebulised ammonium sulphate as well as of secondary organic aerosol generated from a smog chamber were performed. Agreement and discrepancies between the instruments and to the theory are discussed, and final recommendations for a standard instrument are given, as a benchmark for laboratory or field experiments to ensure a high quality of HTDMA data.JRC.H.2-Climate chang

    Productivity and reserve carbohydrates of pastures under cutting intensities

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    There is a need to better understand the effects that cutting or grazing exert on forage, thus to facilitate planning of management that will not be detrimental to the productivity or persistence of the plants. To this end, experimentation was conducted in the pastures of the Experimental Station of Empresa Pernambucana de Pesquisa Agropecuária, Itambé-PE to determine the effect of height of cutting on dry matter production (DMP), daily rate of DMP, total N accumulation, and concentration of reserve carbohydrate (RC) in the herbage. A completely randomized experimental design was used, with five replicates per treatment: Brachiaria decumbens and B. humidicola cut at heights of 5, 15, and 25 cm and at 25 cm plus 80 kg of N/ha; and Pennisetum purpureum cut at 5, 25 and 50 cm and 50 cm plus 80 kg of N/ha. Four cuttings took place, the first during the transitional season from dry to wet (Februrary 2001), and three during the wet season (April, July, and August 2001). The 5 cm cutting height resulted in the greatest DMP and total N accumulation. There was a tendency toward higher concentration of RC in the grass harvested in the transition period during which B. decumbens showed higher RC values than the other two species
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