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Search Results: 1 - 10 of 468085 matches for " María Angélica; "
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Electrical Properties and Phase Behavior of Proton Conducting Nanocomposites Based on the Polymer System (1 - x)[PVOH + H3PO2 + H2O]·x(Nb2O5)  [PDF]
Angélica María Mazuera, Rubén Antonio Vargas
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.55037
Abstract: In the present work, novel blend polymer electrolyte membranes using poly(vinyl alcohol) (PVA), doped with hypophosphorous acid (H3PO2) and reinforced with porous niobium oxide (Nb2O5) microparticles in different compositions were prepared by the solution-casting technique. Their phase behavior and ionic conductivity were studied by differential scanning calorimetric (DSC), thermogravimetric analysis (TGA) and impedance spectroscopy (IS) in the radio-frequency range. Using a constant H3PO2/PVA weigh ratio of 0.25, it was found that the water content in the blended hydrogel membranes increased with increasing the filler Nb2O5 content, thus increasing the electrical conductivity. However, the suitable weight ratio of Nb2O5:(H3PO2/PVA) for the blend performance (both mechanically and electrically) was x = 0.075, with a maximum ionic conductivity of 2.7 × 10﹣3 S·cm﹣1 at 120°C. For all blends prepared, the lost tangent plots show asymmetrical peaks, as a consequence of correlations in the mobile ion diffusion as a function of frequency. Although this “universal dynamic response” was observed at all temperatures, variations in the tan(δ) relaxation peaks indicate a decrease of ionic correlation when the temperature is increased. Both the dc conductivity and tan(δ) peaks frequency dependency are thermally activated, following an Arrhenius-type behavior with activation energy of the same order, indicating that the corresponding ionic processes have the same origin, i.e., proton jump among available sites in the polymer matrix. The additions of oxide particles to the membranes improve their thermal and electrical properties, attributed to an approximation effect.
La teoría platónica del éros en la República
Fierro, María Angélica;
Diánoia , 2008,
Abstract: here, i intend to show that some aspects of the platonic conception of eros which are hinted at in the symposium receive further development in the republic, mainly: a) in the symposium eros is conceived like the intense, universal desire for the good, which is focused in different individuals in different ways (symp. 205d1-9). according to my interpretation, this idea is explained in the psychology of the republic. b) in addition to this in symp. 210a1-212a7 an "erotic ladder" is traced: the love for beautiful bodies; afterwards, for beautiful habits; then, for beautiful sciences; finally, for beauty itself. however, no enlightenment about what these different "levels" refer to is provided. here i show how the whole program of education in the republic constitutes a systematic development of these ideas of the symposium.
Morfometría de unidades de inflorescencia, Flores y políades en especies de la tribu ingeae (mimosoideae)
TAISMA,María Angélica;
Acta Botánica Venezuelica , 2007,
Abstract: a morphometric study was done for spikes and racemes (ia), globose capitate inflorescences (icg) and umbeliform capitate inflorescences (icu) for 19 species of the genera albizia, calliandra, enterolobium, inga, pithecellobium, zapoteca and zygia,tribe ingeae (mimosoideae). ia inflorescences showed hermaphrodite flowers and homomorphic polyads with 24-32 pollen grains. icg inflorescences showed hermaphrodite flowers and a mixture of heteromorphic and homomorphic polyads with 16-24 pollen grains. icu inflorescences were hermaphrodite or andromonoic and showed a majority of heteromorphic polyads with 7-16 pollen grains. positive and significant regression coefficients were found between raquis dimensions and flower number per inflorescence, stamen number per flower, stamen number per inflorescence, pollen grains per flower, pollen grains per inflorescence, ovule number per ovary, ovule number per inflorescence, and p/o. an anova test showed significant differences in morphometric variables related with raquis size, flower size, pollen and ovule production between ia, icg and icu. no prevalence of the andromonoecious condition was found for capitate inflorescences. results suggest morphometric relationships between rachis size of ingeae species and quantitative variables related to resource allocation to male and female inflorescence structures
Crecimiento de tubos polínicos y eficiencia reproductiva en acacia glomerosa benth. (mimosoideae)
Taisma,María Angélica;
Acta Botánica Venezuelica , 2008,
Abstract: three trees of a natural population of acacia glomerosa were studied. the following sexual reproduction variables were measured: number of flowers by inflorescence, number of stamens per flower, number of polyads per stamen, number of pollen per polyad, number of gynoecia with viable and no viable polyads, and numbers of pollen tubes per viable polyad growing at the styles (tpp). the number of fruits per inflorescence, number of seeds per fruit and number of ovules per ovary were also measured. it was found that the pollen/ovule ratio was 3699.14, the seeds/ovule ratio was 0.81 (seed-set), and the fruits/flower ratio per head was 0.08 (fruit-set). these two last ratios show that the total of ovules that produces a plant, only 6.5% (seed-set × fruit-set × 100) becomes seeds in natural pollination. not only the high pollen/ovule ratio, but also the low percentage of ovules that becomes seeds, are coherent with the results of the most of the allogame species. the study of the stigmas in natural pollination reveals that 35% were not pollinated, and from those which were pollinated about 39% contained no viable polyads. these results might indicate that the pollinators in the population are limited, without finding important differences among the three trees studied. the moderate sterility of the polyads or the gynoecias, are both factors limiting the fruit-set. when the stigmas receive a viable polyad, a high percentage of pollen grain fertilizes the ovules of the ovary. this increases the number of seeds in the ripe fruits (ca. 80% of the ovules of ovary becomes a seed).
Política educativa y profundizacion de la desigualdad en chile
Oliva,María Angélica;
Estudios pedagógicos (Valdivia) , 2008, DOI: 10.4067/S0718-07052008000200013
Abstract: the educational unequality became greater during chile's militar dictatorship. although seventeen years have passed after the return to democracy, the situation hasn't improved. this situation deserves being analyzed, which, in this piece of work is carried out from the "deontological" point of view, giving emphasis to three main aspects: conflict between wel-farestate ("estado docente") versus freedom of education ("libertad de ense?anza") and educational unequality; the role of the sub-sidiary state, a fracture upon educational as public wealth, and finally the 1980 constitution and the enforcing of a neoliberal policy upon chilean education.
Razones de una muestra
Palombo,María Angélica;
Subjetividad y procesos cognitivos , 2009,
Abstract: in the frame of a conceptual research, the present work has the objective of exposing a particular sample related to the psychopathological value of emptiness state category. the sample is formed by the emptiness concept present in the work of donald winnicott, otto kernberg, andré green, frances tustin and david maldavsky. these concepts are brought up to analyze how the authors first describe them. then, how they approach the liaison between emptiness and psychological structure and, finally, the theorical approach to these matters, used by them. the object of the research is to find a precise and demonstrable way to establish similitudes and differences in the authors's theories.
Los modos educativos de transmisión en una cátedra de pregrado universitario
Nazur,María Angélica;
Cuadernos de la Facultad de Humanidades y Ciencias Sociales. Universidad Nacional de Jujuy , 2004,
Abstract: in this paper we will analyze the educational transmission modes in psycho diagnosis, a graduate course, at the faculty of psychology, state university at tucumán. these modes are characterized by a set of mechanisms which define certain stages. according to alfredo furlan (1999), the analysis of teaching strategies submits us to searching for a significant clue to understand the greater transmission modes which are carried out at schools. our objectives are to examine two of the transmission modes deployed in teaching psycho diagnosis from the 60's up to the present, in order to characterize and compare them. besides, the formative proposals which derive from them and the context in which they appear will also be studied. the so-called traditional teaching model as well as distance learning are both analyzed taking into account roles, communication, class management and transmission mode. a historical survey shows that the didactic mode is most commonly deployed in the first courses of the career of psychology in tucumán. this transmission mode is centered on the way in which teachers transmit, supporting the basic formative process. in the 90's, however, the curricular mode prevails, insofar as the students' personal progress is highlighted as well as the recovery of their previous knowledge, the linkage with later sections of the career and their future professional performance. at present, the transmission mode of psycho diagnosis is largely curricular, nevertheless it still has some features of the didactic mode, including educational technology.
Política educativa chilena 1965-2009: ?Qué oculta esa trama?
Oliva, María Angélica;
Revista Brasileira de Educa??o , 2010, DOI: 10.1590/S1413-24782010000200008
Abstract: it is discussed the chilean educative policy from the period, enquiring, what does the weft hide? the conjecture is, the educative policy, except the allende's government, shows the neoliberal order institution. some antinomies are revised, mechanisms of that order, that is introduced in 1965 with the pedagogy by objectives and the human capital theory. this pedagogy is made deeper during the dictatorship period, with the subsidiarity idea, that instigate the change of the state's role, ruled in the 1980 constitution, still valid current, and present in the general law of education. the municipalization, the change in the financing and the lost of the status as public employee of teachers, are a legacy of the dictatorship period. this, unsharp the democratic desire of the current educational policy, transforming it into accomplice of a system that generates inequality and social fragmentation.
La justicia en la primera década revolucionaria
Corva,María Angélica;
Revista de historia del derecho , 2010,
Abstract: the suppression of the town council in 1821 led to the judicial reorganization across a pendulous effort for solving from the legislation relating to the moment problems and forming a power of the state of the province of buenos aires. this study has for aim reach to the knowledge of the administration of justice, studying the documents that affected her between 1810 and 1821, to trace the ideas that motivated them and the changes that reached. for this, we will raise first of that the law of 1821 consisted; then we will analyze every document from 1810, finally to recover all the theoretical contributions and of organization to the provincial justice. we think that in this first decade there began a process in which they were seeking to overcome the functions established by the royal ordinance for intendants and to come this way to the division of power, for which was indispensable to take from him to the town council the function of justice, to organize the formal first instance and the informal justice of peace, without need to create a high court as that of the constitution of 1819, expecting to join in some moment to a state nation.
Las vías administrativas y judiciales para la resolución de conflictos de tierras en la provincia de Buenos Aires, 1860--1880
Corva,María Angélica;
Revista de historia del derecho , 2011,
Abstract: the early years of institutional organization and profound changes in social and economic life of the province of buenos aires, involved the resurgence of insecurity in the border, where the installation was unattractive. a group of neighbors mobilized to lead the fort esperanza, and then to retain the ejido lands that the state promised the property, regardless of whether they had an owner, rancher luis goya. the conflict, which passed through various administrative and judicial instances over twenty years (1860-1880), allow to study the ways in which civil society actors tried to resolve the conflicts generated by the possession of the land.
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