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Search Results: 1 - 10 of 12785 matches for " Marcelo; "
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Clinical Psychophysical Assessment of the ON- and OFF-Systems of the Magnocellular and Parvocellular Visual Pathways  [PDF]
Marcelo Fernandes Costa
Neuroscience & Medicine (NM) , 2011, DOI: 10.4236/nm.2011.24043
Abstract: We developed a psychophysical paradigm for the clinical assessment of the contrast sensitivity (CS) mediated by the ON- and OFF-systems of the Magnocellular and Parvocellular pathways. We designed a stimulus considering two dimensions: two spatial frequencies (0.5 and 4.5 cpd) and two temporal rates of flicker (33 ms and 1500 ms). To evidence the ON- and OFF responses, the CS was measured for two polarities of light with luminance changes of 0.6 dB steps above and below the medium luminance grey background. We tested 38 healthy volunteers. The results shows that Magnocellular contrast sensitivity was higher than Parvocellular for the 33 ms flickering stimulus and the Parvocellular contrast sensitivity was higher than Magnocellular for 1500 ms stimuli. The reliability of the test was checked and confirmed. We concluded that the test performs a rapid measurement of the CS mediated by the ON and OFF systems of Magnocellular and Parvocellular pathways. It is useful in clinical protocols due to its high sensitivity and good reliability.
Heat Flow as Origin of Dark Energy  [PDF]
Marcelo Samuel Berman
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.410175

We first introduce entropy according to University Physics textbooks, then, briefly discuss it, and then we prove by a general relativistic derivation that the Universe has entropy growth, like a white-hole, that it is R2-dependent, and that dark energy, represented by a cosmological constant, is caused by heat flow, and provides for entropy growth.

Titanium Oxide Nanorods pH Sensors: Comparison between Voltammetry and Extended Gate Field Effect Transistor Measurements  [PDF]
Elidia Maria Guerra, Marcelo Mulato
Materials Sciences and Applications (MSA) , 2014, DOI: 10.4236/msa.2014.57049
In recent years there has increased interest in the characterization of titanium oxide nanorods for application in analytical devices. The titanium oxide nanorods (NRTiO) were obtained by hydrothermal reaction with a NaOH solution heated in the autoclave at 150°C for up to 50 h. Experimental data indicate that the prepared nanorods consist of anatase and rutile phases, with a possible interlayer structure. The NRTiO was investigated as pH sensor in the pH range 2 - 12, and the extended gate field effect transistor (EGFET) configuration presented a sensitivity of 49.6 mV/pH. Voltammetric data showed a sensitivity of 47.8 mV/pH. These results indicate that the material is a promising candidate for applications as an EGFET-pH sensor and as a disposable biosensor in the future.
Positive solutions of higher order quasilinear elliptic equations
Marcelo Montenegro
Abstract and Applied Analysis , 2002, DOI: 10.1155/s1085337502204030
Abstract: The higher order quasilinear elliptic equation −Δ(Δp(Δu))=f(x,u) subject to Dirichlet boundaryconditions may have unique and regular positive solution. If thedomain is a ball, we obtain a priori estimate to the radialsolutions via blowup. Extensions to systems and general domainsare also presented. The basic ingredients are the maximumprinciple, Moser iterative scheme, an eigenvalue problem, apriori estimates by rescalings, sub/supersolutions, andKrasnosel'skiĭ fixed point theorem.
Producir para el agro en un entorno turbulento: El caso de una fábrica de cosechadoras en la Argentina
Mundo agrario , 2007,
Abstract: the production of rural machines in argentina has its beginning very early, stimulated by the great opportunities that gave the cereal production. a remarkable trait of this sector is the tradition of technological innovation encouraged without any doubt by the specific nature of the agricultural production in our country and the high cost of the imported machinery. this tradition of innovation and the land tapestry will be the key to understand the development of a firm of harvest machines in the south of santa fe since the fifties. we can identify four moments in roque vassalli s.a.'s trajectory, each one is presented in this work in a chronological order that emphasises some aspect of the enterprises dynamic that explains the productive development and the financial-economic evolution of the firm in that period. on a first moment we will see the innovative disposition of the founder partner, his relationship with the public policies to promote the sector and the strong will to create a web of distributors; these are the key factors to the consolidation of this enterprise in the internal market. instead, in a second place we emphasize the problems that it had in the agricultural machinery commerce on the second half of the seventies that ended up affecting its productive and financial situation. on the third part this work focalises on the variables that let us explain the recovery of the enterprise, mainly in the important dynamic of the internal market but also in the commercialization strategies and the capture of the wide external markets. finally, the analysis on the fourth part remarks the thin limits that had the macroeconomic conjuncture over the entrepreneur negotiation, which ended up with the selling of the firm.
Jardín de los ni?os
ARQ (Santiago) , 2003, DOI: 10.4067/S0717-69962003005500006
Abstract: as houellebecq talks of "broadening the battleground", others might speak of "broadening the playground". it?s not just football pitches or yards; urban parks offer scope to extend play space in the city space. situationist efforts to use streets and public places as the setting for new experiences speak to the children?s pavilion that forms part of a plan to recover an old park in the heart of the city of rosario, argentina.
El espacio rural entre la producción y el consumo: algunas referencias para el caso argentino
EURE (Santiago) , 1999, DOI: 10.4067/S0250-71611999007500003
Abstract: in this short article we want to reflect about the modifications that have been occurred in the rural means as well as in the conceptualizations that have been elaborated at this respect. in the developed countries, and in the south? countries too, the rural area at the end of the century is different in so many aspects that we could observe some decades ago. it is not only about changes in the functional or physical aspects, but also we face some deep mutations in the way of valuing to the rural by the urban, this implicate that is modeled (structural and functionality) in base to these valuations. an of the most complete expressions of these modifications are the changes in the conceptualization of the use of rural?s space: before this changes it was a space for the production, nowadays it is a space for the consumption. but not for the consumption of the produced, but for the consumption of the space in itself. the rural tourism, in their multiple facets is a clear example of this
Los trazados de la sal: Lugar y paisaje: transformaciones culturales , salinas de CAHUIL, VI Región
ARQ (Santiago) , 2002, DOI: 10.4067/S0717-69962002005000017
Abstract: the salt marshes of cáhuil conform a landscape shaped by a gulf of sea water that penetrates several kilometres inland between two capes because of a coastal depression. it is a productive landscape that stays almost unaffected by change as from the colonial time thus bespeaking of the transformation of the natural environment as an act of developmen
Las aguas ocultas de Valparaíso
ARQ (Santiago) , 2009, DOI: 10.4067/S0717-69962009000300007
Abstract: the topography forces the modification of the regular urban weave and generates variations, such as the folds leading the waterways. valparaiso is understood in its crevices, in the relationships between the hills, the waters and the sea. it is in this way that its inhabitants adapt to the geography and benefit from it.
Los bajos de los edificios altos: Un itinerario construido con 4 visitas puntuales
ARQ (Santiago) , 2006, DOI: 10.4067/S0717-69962006000200006
Abstract: the engagement between architecture and gravity force is particularly noticeable within the ground floor of any building. this stratum displays the unavoidable link of architectural project with material world, including carrying of loads, support, structure and even its considerations to context.
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