53 research outputs found
Gate recess engineering of pseudomorphic In0.30GaAs/GaAs HEMTs
No full textThe authors report how the performance of 0.12 μm GaAs pHEMTs is improved by controlling both the gate recess width, using selective dry etching, and the gate position in the source drain gap, using electron beam lithography. pHEMTs with a transconductance of 600 mS/mm, off state breakdown voltages >2 V, fτ of 120 GHz, f max of 180 GHz and MAG of 13.5 dB at 60 GHz are reported
Regularity of solutions to higher-order integrals of the calculus of variations
No full textWe obtain new regularity conditions for problems of calculus of variations with higher-order derivatives. As a corollary, we get non-occurrence of the Lavrentiev phenomenon. Our main regularity result asserts that autonomous integral functionals with a Lagrangian having coercive partial derivatives with respect to the higher-order derivatives admit only minimisers with essentially bounded derivatives
Alfred Marshall And "evolutions" Victorian: Situating Darwin And Spencer Theoretical Foundations Of Thought Marshallian [alfred Marshall E As "evoluções" Vitorianas: Situando Darwin E Spencer Nos Fundamentos Teóricos Do Pensamento Marshalliano]
No full textStarting from a comparative study of the theoretical views of Charles Darwin and Herbert Spencer on the processes of change, this paper seeks to understand how the genesis of these ideas about evolution influenced the economic thought of Alfred Marshall. In this sense, we first present how Darwin and Spencer built completely different and irreconcilable approaches to understanding the phenomena of change in complex systems. Subsequently, we try to understand how Marshall absorbed these Victorians elaborations about evolution within his own theoretical construct. Thus, focusing our investigation on Principles (1890) and working with the ideas contained therein about change, progress, equilibrium and representative firm, we seek to show that Marshall followed a code of science characteristically Spencerian, where his approach, often interpreted as "evolutionary," presents no contradiction or incompatibility with a perspective based on neoclassical essentialism.223417450Alvey, J., Some Thought on the Philosophical and Value Assumptions underlying Marshall's Principles of Economics (1987) Macquire University School of Economic and Financial Studies, (317). , Research paperAspers, P., The Economic Sociology of Alfred Marshall (1999) American Journal of Economics and Sociology, 58 (4), pp. 651-667Baiardi, D., (2008) Conhecimento, Evolução e Complexidade na Filosofia Sintética de Herbert Spencer, , Dissertação de Mestrado. Faculdade de Filosofia e Ciências Humanas, USPCarneiro, R.L., Structure, Function, and Equilibrium in the Evolutionism of Herbert Spencer (1973) Journal of Anthropological Research, 29 (2), pp. 77-95Darwin, C., (1859) A Origem das Espécies, , São Paulo: Martin ClaretDawkins, R., (2008) The Oxford Book of Modern Science Writing, , Oxford: Oxford University PressDennet, D.C., (1995) A Perigosa Ideia de Darwin, , Rio de Janeiro: RoccoDennet, D.C., The Selfish Gene as a Philosophical Essay (2006) Richard Dawkins: How a Scientist Changed the Way We Think, , In: GRAFFEN, ARIDLEY, M. (2006). Oxford: Oxford University PressFishburn, G., Natura non facit saltum in Alfred Marshall and Charles Darwin (2004) History of Economics Review, (40), pp. 60-68Foa, B., Marshall revisited in the Age of DNA (1982) Journal of Post Keynesian Economics, 5 (1), pp. 3-16Foucault, M., (1966) As Palavras e as Coisas: Uma arqueologia das ciências, , São Paulo: Martins FontesFoss, J.N., The Suppreion of Evolutionary Approaches in Economics: The Case of Marhall and Monopolistic Competition (1991) Methodus, pp. 65-72. , dezembroFoss, J.N., The Biological Analogy and the Theory of the Firm: Marshall and Monopolistic Competition (1994) The Foundations of Evolutionary Economics: 1890-1973, , In: HODGSON, Geoffrey M. (1998) Cheltenham: Edward ElgarFoss, J.N., Thorstein B. Veblen: Precursor of the Competence-Based Approach to the Firm (1996) DRUID Working Paper, 15 (96). , novembroFreeman, D., The Evolutionary Theories of Charles Darwin and Herbert Spencer (1974) Current Anthropology, 15 (3), pp. 211-237Galbraith, J.K., (1977) A Era da Incerteza, , São Paulo: PioneiraGlassburner, B., Alfred Marshall on Economic History and Historical Development (1955) The Quarterly Journal of Economics, 69 (4), pp. 577-595Gould, S.J., Introduction (1982) Genetics and the Origin of Species, , In: DOBZHANSKY, Theodosius. (1937). New York: Columbia University PressGuillebaud, C., The Evolution of Marshall's Principles of Economics (1942) The Economic Journal, 52 (208), pp. 330-349Groenewegen, P., (1995) A Soaring Eagle: Alfred Marshall 1842-1924, , Hants: Edward ElgarHaines, V.A., Is Spencer's Theory an Evolutionary Theory? (1988) The American Journal of Sociology, 93 (5), pp. 1200-1223Haines, V.A., Spencer's Philosophy of Science (1992) The British Journal of Sociology, 43 (2), pp. 155-172Hammond, J., Alfred Marshall's Methodology (1991) Methodus, pp. 95-101. , junhoHiskes, R.P., Spencer and the Liberal Idea of Community (1983) The Review of Politics, 45 (4), pp. 595-609Hodgson, G., The Mecca of Alfred Marshall (1993) Economic Journal, 103, pp. 406-415Hodgson, G., Introduction (1998) The Foundations of Evolutionary Economics: 1890-1973, , In: HODGSON, Geoffrey M. (1998) Cheltenham: Edward ElgarHodgson, G., How Can Evolutionary Economics Evolve? (2001) Evolutionary Controversies in Economics, , In: ARUKA, Y. (2001). New York: SpringerHodgson, G., Darwinism, Causality and the Social Sciences (2004) Journal of Economic Methodology, 11 (2), pp. 175-194. , junhoHuxley, J., Darwin (1940) Biblioteca do Pensamento Vivo, , In: São Paulo: Martins EditoraJablonka, E., Lamb, M.J., (2005) Evolution in Four Dimensions, , Cambridge: The Massachusetts Institute of Technology PressKeynes, J.M., Alfred Marshall, 1842-1924 (1924) The Economic Journal, 34 (135), pp. 311-372la Vergata, A., Herbert Spencer: Biology, Sociology, and Cosmic Evolution (1995) The Foundations of Evolutionary Economics: 1890-1973, , In: HODGSON, G M (1998) Cheltenham: Edward ElgarLeakey, R., Introdução (2007) A Origem das Espécies, , In: DARWIN, Charles. (1859). São Paulo: Martin ClaretLeão, I.C., Notas Sobre Marx, Darwin e o Progresso (2001) Economia e Sociedade, (16), pp. 141-145Lévi-Strauss, C.C., (1962) O Pensamento Selvagem. São Paulo: PapirusLevine, A., Marshall's Principle and the "Biological Viewpoint": A Reconsideration (1983) Manchester School of Economics and Social Studies, 51 (3), pp. 276-293Loasby, B., Marshall's Economics of Progress (1986) Journal of Economic Studies, 13 (5), pp. 16-26Loasby, B., Firms, Markets, and the Principle of Continuity (1990) Centenary Essays on Alfred Marshall, , In: WHITAKER, J. (1990). (Org.). Cambridge: Cambridge University PressLuz, M.R.S., Fracalanza, P.S., Da Te(le)ologia ao Evolucionário: O legado essencialista e a possibilidade darwiniana de teorização econômica (2010) Anais, , In: Anpec, 38, 2010, Salvador. SalvadorMarshall, A., The Present Position of Economics (1885) Memorials of Alfred Marshall, , In: PIGOU, A. C. (1925). Londres: MacmillanMarshall, A., (1890) Princípios de Economia, , São Paulo: Abril CulturalMarshall, A., Mechanical and Biological Analogies in Economics (1898) Memorials of Alfred Marshall, , In: PIGOU, A. C.(1925). 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Charles Darwin e a Gênese do Moderno Pensamento Evolucionista, , Ribeirão Preto: FUNPEC EditoraMoss, L., Biological Theory and Technological Entrepreneurship in Marshall's Writings (1982) Eastern Economic Journal, 8 (1), pp. 3-13Moss, L., Evolutionary Change and Marshall's Abandoned Second Volume (1990) Economie Appliquée, 43 (1), pp. 85-98Nelson, R., Recent Evolutionary Theorizing About Economic Change (1995) Journal of Economic Literature, 1 (33), pp. 48-90. , marçoNelson, R., Winter, S.G., (1982) Uma Teoria Evolucionária da Mudança Econômica, , Campinas: Editora UnicampParsons, T., Economics and Sociology: Marshall in Relation to the Thought of his Time (1932) The Quarterly Journal of Economics, 46 (2), pp. 316-347Perrin, R.G., Herbert Spencer's Theories of Social Evolution (1976) The American Journal of Sociology, 81 (6), pp. 1339-1359Pigou, A.C., An Analysis of Supply (1928) Economic Journal, (38), pp. 238-257Popper, K., (1950) A Sociedade Aberta e Seus Inimigos, , Belo Horizonte: Livraria Itatiaia Editora LtdaReisman, D., (1987) Alfred Marshall, progress and politics, , Londres: MacMillanScrepanti, E., Zamagni, S., (2005) An Outline of the History of Economic Thought, , New York: Oxford University PressSober, E., Evolution, Population Thinking and Essentialism (1980) Philosophy of Science, 47 (3), pp. 350-383Spencer, H., (1851) Social Statics, , London: RoutledgeSpencer, H., (1857) Do Progresso: Suas Leis e Suas Causas, , Lisboa: InqueritoSpencer, H., (1862) First Principles, , London: RoutledgeStaveley, R., Alvey, J., The Philosophical Assumptions Underlying Marshall's Economics (1988) Alfred Marshall Critical Assessments, , In: WOOD, J.(1988). 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Comparative morphometric studies of the sting apparatus of the worker bees of four different Apis species (Apis dorsata, Apis mellifera, Apis cerana and Apis florea)
No full textTwo glands associated with the sting apparatus of worker honey bees produce venom. The aim of this study was to analyse the size and morphometrics of the sting apparatus of worker bees of four Apis species. The sting apparatus consists of a venom gland, venom sac or venom reservoir and sting. These structures are located in the posterior region of the abdomen between the rectum and ovaries. The venom gland is a long tubular filamentous region (acid gland) connected to a reservoir at its proximal region in which the venom is stored. The distal end of the reservoir or venom sac is connected to the bulb of the sting, which leads into the venom canal present inside the shaft of the sting. Little variation was observed in the morphology of the sting apparatus of the different Apis species, although significant variations were found in the length and width of the different parts of sting apparatus. Copyright © 2013 IBRA
Effect of truck speed on the response of flexible pavement systems to traffic loading
No full textThe road network in South Africa, particularly in urban areas, is experiencing a steady increase in traffic
volumes and congestion. Speed has a significant effect on the response of flexible pavement systems
to traffic loading. Truck tyre loads are more often analysed as a static load in order to simplify the
computations, although in reality the pavement system is subjected to a dynamic load. This paper
investigates the influence of truck speed on flexible pavement system response to moving traffic
loading. A truck with standard axle loads was used to conduct runs at controlled speeds and wander
over a full-scale instrumented pavement test sections on road R104 east of Pretoria. The findings of
this research indicate that pavement deflections increase exponentially as the truck speeds reduce to
speeds below 30 km/h. Furthermore, deflections decrease marginally as the truck speeds increase to
speeds greater than 40 km/h. Different flexible pavement systems present different exponential factors
that reflect differences in sensitivity of the pavement systems to changes in truck speed. It is thus
essential to introduce adjustment factors to deflection measurements done at different truck speeds
on different pavement systems in order to compare such deflection data.SANRAL, University of Pretoria and the National Research Foundation of South Africa.https://www.tandfonline.com/loi/gpav20am2020Civil Engineerin
Model Of The Electronic Structure Of Amorphous Germanium Tin Alloys
No full textThe electronic structure of an amorphous Ge-Sn alloy is modelled by an extension of the coherent potential approximation (CPA), which takes into account the chemical order and the absence of Sn dangling bonds found experimentally. In accordance with experiment, the present calculations predict a smooth linear decrease of the band gap with tin concentration. With respect to transport properties, however, an important difference appears. No electronic levels are theoretically found in the band-gap, which seem to be present in deposited samples, as deduced from conductivity vs temperature measurements. Therefore, these defect centers should arise from local bonding configurations other than the pure tetrahedral substitutional one. © 1990.742103108Amorphous Silicon Technology, (1988) Proc. Materials Research Society, 118. , See for instance, A. Madan, M.J. Thompson, P.C. Taylor, P.G. de Comber, Y. Hamakawa, M.R.S, Pittsburgh, PAJackson, (1958) Trans. Conf. on the Use of Solar Energy, , An extensive literature exists on these structures, which were proposed by, University of Arizona Press, Tucson, AZ, in the Proceedings of the IEEE Photovoltaic Specialists Conferences, Ed. IEEE, New YorkKuwano, Ohnishi, Nishiwaki, Tsuda, Fukatsu, Nakashima, Tarui, (1982) Proc. 16th IEEE Photovoltaic Specialists Conf., p. 1338. , Ed. IEEE, New YorkChambouleyron, Marques, (1989) J. Appl. Phys., 65, p. 1591Amorphous Silicon Technology, (1988) Proc. Materials Research Society, 118, p. 685. , See also, A. Madan, M.J. Thompson, P.C. Taylor, P.G. Le Comber, Y. Hamakawa, M.R.S, Pittsburgh, PATrumbore, Solid Solubilities and Electrical Properties of Tin in Germanium Single Crystals (1956) Journal of The Electrochemical Society, 103, p. 597Verie, Rochette, Rebuillat, (1981) J. Phys. C, 10, p. 667. , See for exampleTemkin, Connell, Paul, (1972) Solid State Commun., 11, p. 1591Chambouleyron, Marques, de Souza, Baumvol, (1988) J. Appl. Phys., 63, p. 5596Castillo-Alvarado, Contreras-Puente, Barrio, (1988) J. Phys. C, 21, p. 1887Barrio, Carriço, Sanjurjo, Chambouleyron, (1989) J. Phys. Condens. Matter, 1, p. 69Tagüeña-Martinez, Barrio, Castillo-Alvarado, Hydrogenated amorphous silicon as a binary alloy (1987) Journal of Physics C: Solid State Physics, 20, p. 1679Carriço, Elliott, Barrio, Model of electronic states at the Si-SiO_{2} interface (1986) Physical Review B, 34 B, p. 872Barrio, Elliott, (1982) J. Phys. C, 15, p. 4493Chadi, Cohen, (1975) Phys. Status Solidi (b), 68, p. 405. , Vol. 1Mailhiot, Duke, Chadi, (1985) Phys. Rev. B, 31, p. 2213Yndurain, Barrio, Elliott, Thorpe, (1983) Phys. Rev. B, 28, p. 3576Rochow, Abel, The Chemistry of Ge, Sn and Pb (1975) Texts in Inorganic Chemistry, 14. , Pergamon Press, U.KLey, Kawalczyk, Pollak, Shirley, (1972) Phys. Rev. Lett., 24, p. 1008Chambouleyron, Marques, Dionisio, Baumvol, Barrio, (1989) J. Appl. Phys., 66, p. 2083R.A. Barrio, I. Chambouleyron & J. Tagüeña-Martinez, unpublishe
In silico analysis of the interaction of de novo peptides derived from Salvia hispanica with anticancer targets
No full textCancer is one of the leading causes of death worldwide. Conventional cancer therapies are not selective to cancer cells resulting in serious side effects on patients. Thus, the need for complementary treatments that improve the patient’s response to cancer therapy is highly important. To predict and evaluate the physicochemical characteristics and potential anticancer activity of the peptides identified from S. hispanica protein fraction <1 kDa through the use of in silico tools. Peptides derived from Salvia hispanica’s protein fraction <1 kDa were identified and analyzed for the prediction of their physicochemical properties. The characterized peptide sequences were then submitted to a multi-criteria decision analysis to identify the peptides that possess the characteristics to potentially exert anticancer activity. Through molecular docking analysis, the potential anticancer activity of the Potentially Anticancer Peptide (PAP)-1, PAP-2, PAP-3, PAP-4, and PAP-5 was estimated by their binding interactions with cancer and apoptosis-related molecules. All five evaluated PAPs exhibited strong binding interactions (< −100 kcal/mol). However, PAP-3 showed the lowest binding free energies with several of the targets. Thus, PAP-3 shows potential to be used as a nutraceutical or ingredient for functional foods that adjuvate in cancer treatment. Conclusions: Through the molecular docking studies, the binding of the PAPs to target molecules of interest for cancer treatment was successfully simulated, from which PAP-3 exhibited the lowest binding free energies. Further in vitro and in vivo studies are required to validate the predictions obtained by the in silico analysis
Arrested Plasmodium liver stages as experimental anti-malaria vaccines.
No full textEukaryotic pathogens typically follow a complex life cycle, including host switch and morphologically distinct forms. Parasite stage conversion offers exceptional opportunities for whole organism vaccine development. In case of Plasmodium, the causative agent of malaria, disease is exclusively caused by asexual blood stages that invade and replicate within erythrocytes. Pathogenic blood stage infections are preceded by a silent parasite growth phase inside the liver. Two alternative experimental whole organisms vaccine strategies that lead to arrested Plasmodium liver stages elicit potent, lasting immunity against re-infection. Live irradiation- or genetically arrested parasites are metabolically active and correspond to classical attenuated vaccines. Specific antimalarial treatment during experimental natural sporozoite infections prevents a febrile malaria episode and, simultaneously, induces effective anti-liver stage immunity. Translation of these strategies into a safe, affordable, and accessible pediatric anti-malaria vaccine requires major bioengineering and pharmaceutical improvements, respectively, but holds promise for a truly effective immunization scheme against the most prevalent and fatal vector-borne disease
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