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Search Results: 1 - 10 of 140379 matches for " Eugenio K.;Leiras "
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Otimiza??o conjunta de gráficos de X-barra - S ou X-barra - R: um procedimento de fácil implementa??o
Epprecht, Eugenio K.;Leiras, Adriana;
Produ??o , 2007, DOI: 10.1590/S0103-65132007000300009
Abstract: a model is developed for optimum choice of the operation parameters for x-bar - r (or x-bar - s) charts, which minimizes the ratio of sampling costs to detection speed of shifts in the process mean or increases in the process dispersion. three alternative problem formulations are allowed: minimization of the average time to signal subject to a sampling cost constraint; minimization of the sampling cost subject to a constraint on the average times to signal; and multi-objective optimization of both the average time to signal and the sampling cost. through optional additional constraints, several practical variants of the problem are admitted. the procedure avoids the complexity of usual economic design models, and methods for determining the values for the few input and specification parameters required are given in detail. an example shows that the procedure is easy to apply. all these features increase its applicability for a wide range of typical practical situations.
Planejamento do controle estatístico de processos com baixa fra??o n?o conforme restrito a amostras pequenas
Epprecht, Eugenio Kahn;Leiras, Adriana;Costa, Antonio Fernando Branco;
Produ??o , 2007, DOI: 10.1590/S0103-65132007000100010
Abstract: we present the non-conventional design of np charts used for the surveillance of processes characterized by a very low fraction nonconforming, with a costly and/or time-consuming inspection procedure, which makes the inspection of large samples prohibitive. under these circumstances, the trade-off between the false-alarm rate and the speed with which the chart signals process deteriorations is the basis to design the control chart, once (depending on the sample size) the conventional np chart with "three-sigma" limits offers little protection against false alarms or is slow in detecting process disturbances. the study was motivated by the real case of a newspapers packaging process. the nominal number of newspapers in the package depends on the newspaper's breadth, and packages with a number of newspapers different from nominal are considered nonconforming.
Los procesos de descentralización y la nacionalización de los sistemas de partidos en América Latina
Leiras, Marcelo;
Política y gobierno , 2010,
Abstract: recent theories argue that decentralization induces party system denationalization because the transfer of financial resources and administrative responsibilities renders sub-national governments more relevant. the effect only holds if: a) voters can judge sub-national policies but the institutional environment prevents them from voting for different parties in election for offices of different level; or b) if sub-national party organizations have incentives to prioritize sub-national competition. a comparative analysis of four highly decentralized latin american countries and a closer look at the argentine case confirm the validity of this interpretation. the results suggest that decentralization may alter territorial patterns of political competition depending on how evolves, for other reasons, the relationship between arenas of different level. in order to analyze more conclusively the relationship between decentralization and party nationalization it is necessary to refine existing theories and apply improved estimation techniques that allow for the identification of endogenous effects.
Argentina: Problemas Macroeconómicos, Conflicto Social y Debilitamiento de la Coalición de Gobierno
LEIRAS,MARCELO; CRUZALEGUI,INéS;
Revista de ciencia política (Santiago) , 2009, DOI: 10.4067/S0718-090X2009000200001
Abstract: in 2008, difficulties found in the resolution of macro-economic problems weakened the liases of support of the argentine national government. this common occurrence, in this case presents singular traits. it takes place after four years of good social and economic performance and follows an electoral result clearly favorable to the incumbent government. in order to increase public income, the national government proposed to increase agricultural export duties. agricultural producers and their representativeorganizations■ forcefully'resisted theproposal,wmchwas eventually defeatedincongress. after the legislative defeat and a fall in public approval ratings, the government partially recomposed its position, leaning on the basic structure of its legislative coalition and promoting proposals that could gather support from ideologically motivated allies. the impact of the international economic crisis and the result of the 2009 mid-term elections will test the robustness of the recomposed coalition.
Argentina: Problemas Macroeconómicos, Conflicto Social y Debilitamiento de la Coalición de Gobierno Argentina: Macro-economic Problems, Social Conflict and Weakening of the Governing Coalition
MARCELO LEIRAS,INéS CRUZALEGUI
Revista de Ciencia Política , 2009,
Abstract: En 2008 las dificultades para resolver problemas macroeconómicos debilitaron las bases de sustentación política del gobierno nacional argentino. Este problema común presenta en este caso rasgos singulares. Tiene lugar tras cuatro a os de muy buen desempe o económico y social y luego de un resultado electoral claramente favorable al oficialismo. Con el propósito de incrementar los ingresos públicos, el gobierno nacional propuso aumentar la tasa de retención a las exportaciones agropecuarias. Los productores y sus organizaciones representantes resistieron fuertemente la medida, que finalmente fue derrotada en el Congreso. Tras la derrota legislativa y una caída en la imagen pública, el gobierno recompuso parcialmente su posición, apoyándose en la estructura básica de su coalición legislativa y promoviendo propuestas que pudieran sumar aliados ideológicamente motivados. El impacto de la crisis internacional y el resultado de las elecciones de renovación legislativa de 2009 pondrán a prueba la robustez de la coalición recompuesta. In 2008, difficulties found in the resolution of macro-economic problems weakened the liases of support of the Argentine national government. This common occurrence, in this case presents singular traits. It takes place after four years of good social and economic performance and follows an electoral result clearly favorable to the incumbent government. In order to increase public income, the national government proposed to increase agricultural export duties. Agricultural producers and their representativeorganizations■ forcefully'resisted theproposal,wMchwas eventually defeatedinCongress. After the legislative defeat and a fall in public approval ratings, the government partially recomposed its position, leaning on the basic structure of its legislative coalition and promoting proposals that could gather support from ideologically motivated allies. The impact of the international economic crisis and the result of the 2009 mid-term elections will test the robustness of the recomposed coalition.
Um método simples para o projeto ótimo de gráficos de X
Epprecht, Eugenio K.;Santos, Alessandra Bastos dos;
Gest?o & Produ??o , 1998, DOI: 10.1590/S0104-530X1998000300004
Abstract: a simple but efficient method has been developed for the design of -charts. the solutions provided are optimal in terms of the ratio between the number of items inspected per unit time and the detection speed (defined as the inverse of the average time to signal a shift in the mean). the method is superior to design procedures based exclusively on statistical properties of the chart (such as the arl), and does not have the implementation drawbacks of economical design models. the results obtained differ from some results widely reported in the literature, which are shown to be sub-optimal as a consequence of their underlying model not considering some important aspects of the problem. an additional contribution of the method is the explicit treatment of optional constraints on the sample size and/or on the interval between samples. the ease of use of the method makes its implementation straightforward in any environment, and also makes it suitable for the classroom.
An Integrated Supply Chain Perspective Evaluation for Biodiesel Production in Brazil
Adriana Leiras,Silvio Hamacher,Luiz Felipe Scavarda
Brazilian Journal of Operations & Production Management , 2010,
Abstract: Biodiesel has been highlighted as an important source of energy worldwide, but there is still a lack of research focused on Brazil, a major biofuel producer. Within this context, this paper analyzes the biodiesel supply chain developed from oil plants in Brazil and evaluates its feasibility. To achieve this goal, visits in loco and interviews with 42 participants were conducted across different links in the supply chain, from the farming of oil plants (agricultural production) to the extraction of oil and the production of biodiesel, up to its distribution (logistics) and commercialization. The paper also develops an economic evaluation model that generated 204 scenarios for the complete supply chain analysis for biodiesel produced from soybean, palm, castor, and cotton. Despite the many price fluctuations observed since the beginning of this research (end of 2005), for instance the petroleum diesel and oil plant prices, the conclusion of this work is that biofuel can be a feasible fuel alternative in Brazil. However, further studies should be conducted to address pending issues like the possible competition of the biodiesel supply chain with food chains and the expansion of crop cultivation areas into the native flora in Brazil.
Electrophysiological Study of Supraspinal Input and Spinal Output of Cat's Subnucleus Reticularis Dorsalis (SRD) Neurons
Patricia Velo, Roberto Leiras, Antonio Canedo
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0060686
Abstract: This work addressed the study of subnucleus reticularis dorsalis (SRD) neurons in relation to their supraspinal input and the spinal terminating sites of their descending axons. SRD extracellular unitary recordings from anesthetized cats aimed to specifically test, 1) the rostrocaudal segmental level reached by axons of spinally projecting (SPr) neurons collateralizing or not to or through the ipsilateral nucleus reticularis gigantocellularis (NRGc), 2) whether SPr fibers bifurcate to the thalamus, and 3) the effects exerted on SRD cells by electrically stimulating the locus coeruleus, the periaqueductal grey, the nucleus raphe magnus, and the mesencephalic locomotor region. From a total of 191 SPr fibers tested to cervical 2 (Ce2), thoracic 5 (Th5) and lumbar5 (Lu5) stimulation, 81 ended between Ce2 and Th5 with 39 of them branching to or through the NRGc; 21/49 terminating between Th5 and Lu5 collateralized to or through the same nucleus, as did 34/61 reaching Lu5. The mean antidromic conduction velocity of SPr fibers slowed in the more proximal segments and increased with terminating distance along the cord. None of the 110 axons tested sent collaterals to the thalamus; instead thalamic stimulation induced long-latency polysynaptic responses in most cells but also short-latency, presumed monosynaptic, in 7.9% of the tested neurons (18/227). Antidromic and orthodromic spikes were elicited from the locus coeruleus and nucleus raphe magnus, but exclusively orthodromic responses were observed following stimulation of the periaqueductal gray or mesencephalic locomotor region. The results suggest that information from pain-and-motor-related supraspinal structures converge on SRD cells that through SPr axons having conduction velocities tuned to their length may affect rostral and caudal spinal cord neurons at fixed delays, both directly and in parallel through different descending systems. The SRD will thus play a dual functional role by simultaneously regulating dorsal horn ascending noxious information and pain-related motor responses.
Dise?o de sistemas de medición de desempe?o de proveedores: experiencias de un caso de estudio
Fernandez, Nicole Suclla;Scavarda, Luiz Felipe;Leiras, Adriana;Hamacher, Silvio;
Produ??o , 2012, DOI: 10.1590/S0103-65132011005000043
Abstract: the evaluation of suppliers’ performance is important for organizations because of the imperative role they play in the supply chains and the importance that purchasing functions have due to the outsourcing of activities which are not part of the company’s know-how. there is a need to work on the identification of practical problems concerning the design and implementation of supplier performance measurement systems (spms). this paper presents the most important factors in designing and implementing such systems through an action research in a multinational media enterprise. in addition to the details of the method and results of its application, the paper presents an analysis of processes and attributes that define the design of the proposed system. the authors aim to contribute to the academic literature in providing practical issues regarding spms.
La ciencia política en Argentina: el camino de la institucionalización dentro y fuera de las aulas universitarias
Leiras,Marcelo; Abal Medina (h.),Juan; D'Alessandro,Martín;
Revista de ciencia política (Santiago) , 2005, DOI: 10.4067/S0718-090X2005000100005
Abstract: abstract this article analyzes the development of political science in argentina. it defends four theses. first, that the development of the scientific analysis of politics in argentina stems from the professionalization and internal differentiation of social sciences, is centered in universities and is highly vulnerable to regime change. second, that in the last few years the discipline's academic autonomy grows, supported by the growth of university undergraduate and graduate programs. its autonomy as a field of professional practice evolves at a slower pace. third, that research agendas reflect mainly the priorities of decision makers, international scholarly communities and personal trajectories of local practitioners. public concerns play a less significant role. finally, that the specific contribution of political scientists to political analysis still struggles to clearly define its difference from interventions made by jurists, sociologists, economists and journalists.
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