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Search Results: 1 - 10 of 450055 matches for " J. C. Forte "
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Avalia??o do desempenho de catalisadores híbridos Ziegler-Natta/metaloceno na homo- e copolimeriza??o de etileno
Cunha, Fernanda O. V.;Forte, Madalena C.;Zacca, Jorge J.;
Polímeros , 2000, DOI: 10.1590/S0104-14282000000300008
Abstract: hybrid catalysts formed by a heterogeneous ziegler-natta catalyst (mgcl2.ticl4) and a metallocene (cpticl3) were prepared in this work. the formation of a new catalytic species cpti(ibu)cl2 on the (100) mgcl2 face has been proposed. these catalyst systems were applied to synthesize high density polyethylene (hdpe) and linear low density polyethylene (lldpe), using only triethyl aluminium (tea) as a cocatalyst. the influence of al/ti molar ratio, temperature and time of polymerization on the catalyst activity and on the polymer properties were evaluated. the catalyst activities were about 5.0 kgpol/gcat.h for ethylene polymerization and 7.0 kgpol/gcat.h for ethylene-1-butene coplymerization.
Avalia o do desempenho de catalisadores híbridos Ziegler-Natta/metaloceno na homo- e copolimeriza o de etileno
Cunha Fernanda O. V.,Forte Madalena C.,Zacca Jorge J.
Polímeros , 2000,
Abstract: Foram preparados catalisadores híbridos a partir de um catalisador do tipo Ziegler-Natta heterogêneo (MgCl2.TiCl4) e de um metalocênico (CpTiCl3), afim de se obter catalisadores com diferentes tipos de centros ativos. Foi proposta a forma o de um novo centro ativo (CpTi(iBu)Cl2) na face 100 do suporte de MgCl2. Estes catalisadores foram avaliados na síntese de polietileno de alta densidade (PEAD) e de polietileno linear de baixa densidade (PELBD), utilizando-se somente trietilalumínio (TEA) como cocatalisador. Foi verificada a influência da raz o molar Al/Ti, temperatura e tempo de polimeriza o na produtividade dos catalisadores e nas propriedades dos polímeros obtidos. Os catalisadores mistos apresentaram atividade catalítica da ordem de 5,0 kgPol/g cat.h na polimeriza o de etileno e da ordem de 7,0 kgPol/g cat.h na copolimeriza o etileno-1-buteno.
The Outer Halo Cluster System of NGC 1399
B. Dirsch,D. Geisler,T. Richtler,J. C. Forte
Physics , 2001,
Abstract: We investigate the outer halo globular cluster population of NGC 1399. This study uses wide-field imaging of this cluster system, which covers the largest area studied with CCD photometry until now. The cluster system of NGC 1399 is found to extend further than 100 kpc from the galaxy. A population of metal-rich, as well as metal-poor clusters has been identified at these large radii. At radii smaller than 55 kpc the specific frequency of the red cluster system remains constant, while that of the blue clusters increases proportional to $r^{0.8\pm0.2}$. For larger radii, the uncertainty of the galaxy light profile does not permit any reliable statement.
Doping dependence of magnetic excitations of 1D cuprates as probed by Resonant Inelastic x-ray Scattering
F. Forte,M. Cuoco,C. Noce,J. van den Brink
Physics , 2011, DOI: 10.1103/PhysRevB.83.245133
Abstract: We study the dynamical, momentum dependent two- and four-spin response functions in doped and undoped 1D cuprates, as probed by resonant inelastic x-ray scattering, using an exact numerical diagonalization procedure. In the undoped $t-J$ system the four-spin response vanishes at $\pi$, whereas the two-spin correlator is peaked around $\pi/2$, with generally larger spectral weight. Upon doping spectra tend to soften and broaden, with a transfer of spectral weight towards higher energy. However, the total spectral weight and average peak position of either response are only weakly affected by doping up to a concentration of 1/8. Only the two-spin response at $\pi$ changes strongly, with a large reduction of spectral weight and enhancement of excitation energy. At other momenta the higher-energy, generic features of the magnetic response are robust against doping. It signals the presence of strong short-range antiferromagnetic correlations, even after doping mobile holes into the system. We expect this to hold also in higher dimensions.
Introduzione
C. Forte
Aestimum , 1974,
Abstract:
Enhancing cognitive functioning in the elderly: multicomponent vs resistance training
Forte R, Boreham CA, Costa Leite J, De Vito G, Brennan L, Gibney ER, Pesce C
Clinical Interventions in Aging , 2013, DOI: http://dx.doi.org/10.2147/CIA.S36514
Abstract: hancing cognitive functioning in the elderly: multicomponent vs resistance training Original Research (1902) Total Article Views Authors: Forte R, Boreham CA, Costa Leite J, De Vito G, Brennan L, Gibney ER, Pesce C Published Date January 2013 Volume 2013:8 Pages 19 - 27 DOI: http://dx.doi.org/10.2147/CIA.S36514 Received: 30 July 2012 Accepted: 15 September 2012 Published: 10 January 2013 Roberta Forte,1,2 Colin AG Boreham,1 Joao Costa Leite,3 Giuseppe De Vito,1 Lorraine Brennan,3 Eileen R Gibney,3 Caterina Pesce2 1Institute for Sport and Health, University College Dublin, Dublin, Ireland; 2Department of Human Movement and Sport Science, University of Rome "Foro Italico," Rome, Italy; 3Institute of Food and Health, University College Dublin, Dublin, Ireland Purpose: The primary purpose of this study was to compare the effects of two different exercise training programs on executive cognitive functions and functional mobility in older adults. A secondary purpose was to explore the potential mediators of training effects on executive function and functional mobility with particular reference to physical fitness gains. Methods: A sample of 42 healthy community dwelling adults aged 65 to 75 years participated twice weekly for 3 months in either: (1) multicomponent training, prioritizing neuromuscular coordination, balance, agility, and cognitive executive control; or (2) progressive resistance training for strength conditioning. Participants were tested at baseline (T1), following a 4-week control period (T2), and finally at postintervention (T3) for executive function (inhibition and cognitive flexibility) and functional mobility (maximal walking speed with and without additional task requirements). Cardiorespiratory and muscular fitness were also assessed as potential mediators. Results: Indices of inhibition, the functions involved in the deliberate withholding of prepotent or automatic responses, and measures of functional mobility improved after the intervention, independent of training type. Mediation analysis suggested that different mechanisms underlie the effects of multicomponent and progressive resistance training. While multicomponent training seemed to directly affect inhibitory capacity, resistance training seemed to affect it indirectly through gains in muscular strength. Physical fitness and executive function variables did not mediate functional mobility changes. Conclusion: These results confirm that physical training benefits executive function and suggest that different training types might lead to such benefits through different pathways. Both types of training also promoted functional mobility in older adulthood; however, neither inhibitory capacity, nor muscular strength gains seemed to explain functional mobility outcomes.
Globular cluster candidates within the Fornax Cluster: intracluster globulars?
L. P. Bassino,S. A. Cellone,J. C. Forte,B. Dirsch
Physics , 2002, DOI: 10.1051/0004-6361:20021810
Abstract: We present the results of a search for globular clusters in the surroundings of 15 low surface brightness dwarf galaxies belonging to the Fornax Cluster, which was carried out on CCD images obtained with the C and T1 filters of the Washington photometric system. The globular cluster candidates show an extended and probably bimodal (C-T1) color distribution, which is inconsistent with the presence of a single population of metal-poor clusters detected in several dwarf galaxies. The surface number density of these candidates shows no concentration towards the respective dwarf galaxies, in whose outskirts they have been identified. On the contrary, if we split the candidates in two groups according to their projected distances to the center of the Fornax Cluster, those located closer to the center show a higher projected density than those located farther from it. These results suggest that the potential globular clusters might not be bound to the dwarf galaxies. Alternatively, these globulars could form part of the very peripheral regions of NGC 1399 (the central galaxy of the Fornax Cluster) or even belong to the intracluster medium.
Imobiliza??o de dicloreto de bis(butilciclopentadienil) zirc?nio em adutos de cloreto de magnésio (MgCl2.nEtOH) e seu desempenho em homopolimeriza??o de etileno
Silveira, Flávia D.;Forte, Madalena C.;Santos, Jo?o H. Z.;Stedile, Fernanda C.;Zacca, Jorge J.;
Polímeros , 2000, DOI: 10.1590/S0104-14282000000100008
Abstract: this work describes the preparation of catalysts by the immobilization of bis(n-butylcyclopentadienyl)zirconium dichloride, (nbucp)2zrcl, on magnesium dichloride adducts, mgcl2.netoh. the metal content on the support, which varied from 0,5 to 1,5 wt.-% zr/mgcl2 and the catalysts activity were dependent on the ethanol content. in the temperature immobilization range between 25 and 75°c, the highest zr incorporation and polymerization yield were obtained with the catalyst prepared at 25°c. based on the results obtained in this work, a series of reactions that may occur between the catalyst components during its preparation are proposed. the polyethylenes obtained were characterized by its molecular weight and polydispersivity.
Review Essay: "Is it Real"? Probleme und Perspektiven von Forschung in der "realen Welt" Review Essay: Is it Real? Problems and Prospects of Research in "the Real World" Ensayo: "Is it Real"? Problemas y perspectivas de la investigación en el "mundo real"
Maximilian C. Forte
Forum : Qualitative Social Research , 2002,
Abstract: Dieses Handbuch vermittelt einen sehr nützlichen überblick über verschiedene Strategien, Methoden und Forschungsdesigns in den Sozialwissenschaften, wobei der Autor die Kombination von quantitativen und qualitativen Forschungsmethoden im Sinne eines kritisch-realistischen Paradigmas thematisiert. Den Leser(inne)n wird zun chst ein überblick über die Debatten zu den verschiedenen Forschungsans tzen – von positivistischen bis zu relativistischen Positionen – gegeben; der Autor setzt sich selbst für einen Ansatz ein, den er als "real world research" bezeichnet. In den folgenden Teilen des Buches erhalten die Leser(innen) eine Einführung in das Design von Untersuchungen, in Methoden der Datenerhebung und schlie lich in die Datenanalyse und die Darstellung von Forschungsergebnissen. W hrend das Buch potenziell ein nützlicher Einführungstext für Noviz(inn)en bzw. eher unerfahrene Forschende sein kann, insbesondere, wenn diese sich für politisch orientierte Forschung interessieren, erscheint es weniger geeignet für st rker spezialisierte Leser(innen) mit anderen disziplin ren Schwerpunktinteressen. URN: urn:nbn:de:0114-fqs0204471 This handbook will be very useful as an overview of various strategies, methods and research designs in social research, combining quantitative and qualitative research in a critical realist paradigm. The reader is introduced to debates concerning various approaches to research, from the positivist to the relativist, whilst putting forth an argument for a reconstructed scientific approach that the author calls "real world research." Readers are then introduced to research design, methods of gathering data and then, finally, the analysis of data and reporting on one's enquiry. While this will most likely be a useful introductory text for novice or lay researchers, especially those engaged in research with a policy orientation, more specialized readers in some disciplines might not be as well served. URN: urn:nbn:de:0114-fqs0204471 Este manual trasmite una visión general útil sobre diferentes estrategias, métodos y dise os de investigación en la ciencias sociales, en la que el autor tematiza la combinación de métodos cuantitativos y cualitativos en el sentido de un paradigma crítico-realista. Primero se presenta al lector un resumen de los debates sobre los diferentes principios de investigación (desde la posición positivista hasta la relativista). El autor mismo introduce un principio, que lo caracteriza como "investigación del mundo real". En las secciones posteriores del libro el lector puede encontrar una introducción en dise o de l
Review: Robert V. Kemper & Anya Peterson Royce (Hrsg.) (2002). Chronicling Cultures: Long-term Field Research in Anthropology Review: Robert V. Kemper & Anya Peterson Royce (Eds.) (2002). Chronicling Cultures: Long-term Field Research in Anthropology Rese a: Robert V. Kemper & Anya Peterson Royce (Eds.) (2002). Chronicling Cultures: Long-term Field Research in Anthropology
Maximilian C. Forte
Forum : Qualitative Social Research , 2004,
Abstract: Chronicling Cultures" liefert den Leser(inne)n detaillierte Fallgeschichten ethnographischer Projekte, die lange Zeit, in einigen F llen Jahrzehnte, andauerten und in die oft zahlreiche Mitarbeiter(innen) und neue Forscher(innen)generationen involviert waren. Das zentrale Thema des Textes ist, dass die lange Zeit im Feld zu sowohl qualitativen als auch quantitativen Ver nderungen in der Forschung geführt hat. Die Autor(inn)en des Bandes erforschen diese Ver nderungen unter Berücksichtigung der Daten, die den Prozess, die theoretischen Ergebnisse der Langzeitforschung, die Einflüsse auf die Gastgemeinden und die vielen Probleme und Vorteile einer durch wiederholte Besuche und Studien lang ausdehnten Zeit im Feld zusammengefasst zeigen. Der Band ist vor allem für Leser(innen) wichtig, die sich für die Geschichte der Anthropologie interessieren, weniger für die an Feldmethoden Interessierten. Schw chen des Bandes bestehen in gewisser Hinsicht in der losen thematischen Organisation, in der überm ig deskriptiven Art vieler Beitr ge, in der geringen Vielfalt der ausgew hlten F lle und im Fehlen diverser Perspektiven. URN: urn:nbn:de:0114-fqs0401242 Chronicling Cultures provides readers with detailed case histories of ethnographic projects that are long-term in duration, lasting decades in some cases and often involving multiple collaborators and new generations of researchers. The central theme of the text is that extended time spent in the field leads to both qualitative and quantitative transformations in research. Contributors to the volume examine these transform-ations with respect to the data gathering process, the theoretical outcomes of long-term research, the impacts on host communities and the many problems and benefits of spending extended time in the field through multiple revisits and restudies. The volume will be of especial interest to those interested in the history of anthropology and to a lesser degree those interested in field methods. Amongst the shortcomings of the volume are its somewhat loose thematic organization, the overly descriptive nature of many of the contributions, the narrow range of cases selected and the lack of diverse perspectives. URN: urn:nbn:de:0114-fqs0401242 Este libro proporciona a los lectores detalladas historias de caso de proyectos etnográficos de larga duración, de las últimas décadas en algunos casos e involucrando a menudo colaboradores múltiples y nuevas generaciones de investigadores. El tema central del texto es que el tiempo total invertido en el campo permite las transformaciones cualitativas y cuantitat
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