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Search Results: 1 - 10 of 5219 matches for " Martinez "
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Discrete Evolutionary Genetics: Multiplicative Fitnesses and the Mutation-Fitness Balance  [PDF]
Thierry Huillet, Servet Martinez
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.21002
Abstract: We revisit the multi-allelic mutation-fitness balance problem especially when fitnesses are multiplicative. Using ideas arising from quasi-stationary distributions, we analyze the qualitative differences between the fitness-first and mutation-first models, under various schemes of the mutation pattern. We give some stochastic domination relations between the equilibrium states resulting from these models.
Teaching with an Attitude: Finding Ways to the Conundrum of a Postmodern Curriculum  [PDF]
Ana Paula Martinez Duboc
Creative Education (CE) , 2013, DOI: 10.4236/ce.2013.412A2009
Abstract: Several scholars in the field of education have questioned the constituent aspects of a curriculum that would better respond to the rising demands in contemporary societies. The relevance of such enquiry finds its place in the very transformations in today’s societies marked by significant changes in the ways of knowing, being, and acting primarily due to the advent of new digital media in more recent globalizing processes. As Burke (2009) has stated, if schools wish to maintain their relevance in society, they must take into account such changes by first and foremost acknowledging the new and complex ways of making meanings in out-of-school literacy practices as equally legitimating those happening within school contexts. Along with Burke (ibid.), this paper advocates the need of rethinking the notion of curriculum in the light of the new ontologies and epistemologies of postmodernity. Such task proves itself to be a conundrum inasmuch as the very notion of curriculum has been traditionally founded on modern principles such as linearity, stability, and universality (Silva, 2009). In view of this, how can educators respond to the challenge of redefining what should be taught in schools in postmodern times so that students would better perform in relation to the self and the other within their social practices? This paper aims to analyse the relationship between postmodern philosophical concepts, curriculum theory and educational practice by presenting the notion of curricular attitude (Duboc, 2012) as a local redesign of teaching practices within a Brazilian educational context. Despite being situated in the field of foreign language teaching, the notion of a curricular attitude might be of interest of other areas of knowledge since it seeks to revisit teaching practices in the light of wider philosophical concerns.
Static Properties and Current-Driven Dynamics of Domain Walls in Perpendicular Magnetocrystalline Anisotropy Nanostrips with Rectangular Cross-Section
Eduardo Martinez
Advances in Condensed Matter Physics , 2012, DOI: 10.1155/2012/954196
Abstract: The current-induced domain wall motion along thin ferromagnetic strips with high perpendicular magnetocrystalline anisotropy is studied by means of full micromagnetic simulations and the extended one-dimensional model, taking into account thermal effects and edge roughness. A slow creep regime, where the motion is controlled by wall pinning and thermal activation, and a flow regime with linear variation of the DW velocity, are observed. In asymmetric stacks, where the Rashba spin-orbit field stabilizes the domain wall against turbulent transformations, the steady linear regime is extended to higher currents, leading to higher velocities than in single-layer or symmetric stacks. The pinning and depinning at and from a local constriction were also studied. The results indicate that engineering pinning sites in these strips provide an efficient pathway to achieve both high stability against thermal fluctuations and low-current depinning avoiding Joule heating. Finally, the current-driven dynamics of a pinned domain wall is examined, and both the direct and the alternating contributions to the induced voltage signal induced are characterized. It was confirmed that the direct contribution to the voltage signal can be linearly enhanced with the number of pinned walls, an observation which could be useful to develop domain-wall-based nano-oscillators. 1. Introduction A typical pattern of a ferromagnetic sample consist on a set of domains and domain walls (DWs). The domains are uniformly magnetized regions, and DWs constitute the boundary between them. DWs have been intensively researched in the past, both in bulk or continuous films [1]. However, as many other areas of physics, the study of DWs has been revitalized by the advent of nanotechnology, and at the present, modern nanolithograpy techniques allow the fabrication of suitable ultra-thin ferromagnetic strips where DWs can be easily nucleated. The development of advance microscopy methods has also permitted them to be imaged and their dynamics to be explored. The traditional way to promote the DW dynamics is done by applying magnetic fields. Recently, a more promising alternative to drive DWs has been proposed. It consists on flowing electrical currents though ferromagnetic strip by using the novel physics of spin-transfer torque. Electrical current passing through a ferromagnetic strip becomes spin polarized along the local magnetization direction. When the current crosses a DW, spin angular momentum is transferred from the current to the magnetization, thereby inducing a torque which leads to DW motion.
Further insights of the variance component method for detecting QTL in livestock and aquacultural species: relaxing the assumption of additive effects
Victor Martinez
Genetics Selection Evolution , 2008, DOI: 10.1186/1297-9686-40-6-585
Abstract: (To access the full article, please see PDF)
Narrativas de viagem: escritos autorais que transcendem o tempo e o espa?o
Martinez, Monica;
Intercom: Revista Brasileira de Ciências da Comunica??o , 2012, DOI: 10.1590/S1809-58442012000100003
Abstract: the aim of this paper is to recover the history of travel writing, from its origins in the literature and, after consolidation of journalism in the nineteenth century, in the production of journalists and writers who devoted themselves to the practice, particularly in book form, based on bibliographical resarch. the main topic of this paper is to revive the history of the genre from homer (viii bc) as well as to list the most relevant contemporary journalistic production and reflect on the modality in the context of literary journalism, as well as its connection with other areas of knowledge, such as ethnography and anthropology. the main conclusion of this study is that this method has the potential to play a transforming role for both the producer and the reader of such narratives.
Shoreline changes in Concón and Algarrobo bays, central Chile, using an adjustment model
Martinez,Carolina;
Investigaciones marinas , 2007, DOI: 10.4067/S0717-71782007000200010
Abstract: adjustment models for both algarrobo and concón bays, central chile, are presented herein; the results show a nearly logarithmic spiral shape for the shore. spatial-temporal variations in the shorelines of both bays were found based on aerial photographs from different years. the results indicate important variations in the relative position of the concón bay shoreline between 1945 and 2006, with extreme oscillations (-368 to 123.8 m) only occurring in the proximal zone, where the aconcagua estuary is located. on the other hand, the spatial-temporal variations in the algarrobo bay shoreline between 1967 and 2006 are moderate (131 in the proximal and -73 in the distal zone). whereas concón bay exhibits a stable state of equilibrium for the past 60 years, if the estuary zone is excluded, algarrobo bay presents a stable state with a tendency for growth in the proximal zone and retreat in the distal zone. the results are discussed in terms of coastal changes associated with highly urbanized shorelines and applications for coastal area management that are derived from the models
Atualiza??o no uso de agentes antifúngicos
Martinez, Roberto;
Jornal Brasileiro de Pneumologia , 2006, DOI: 10.1590/S1806-37132006000500013
Abstract: we summarize here data regarding the spectrum of action, the pharmacological aspects, the toxicological aspects and the clinical efficacy of liposomal amphotericin b, amphotericin b in colloidal dispersion, amphotericin b lipid complex, voriconazole and caspofungin. we discuss the use of these more recently introduced antifungal agents in terms of their safety, efficiency and cost. we also offer suggestions for the clinical use of these drugs in pulmonary and systemic infections, with an emphasis on the lower toxicity of the lipid formulations of amphotericin b in comparison with conventional medications. in addition, we explore the possibility of using voriconazole as the primary treatment for invasive infections such as aspergillosis, as well as those caused by scedosporium spp. and fusarium spp., together with that of using caspofungin to treat disseminated candidiasis and invasive aspergillosis.
Conducta alimentaria de Daphnia ambigua Scourfield 1947, Moina micrura Kurz 1874 y Ceriodaphnia dubia Richard 1895 (Cladocera) frente a un gradiente de concentración de alimento
MARTINEZ,GINGER;
Revista chilena de historia natural , 2000, DOI: 10.4067/S0716-078X2000000100006
Abstract: because cladocera is the most abundant group of filter-feeders in the freshwater zooplankton and their populations are usually found under limited resources conditions, the individual response under a resources concentration gradient has important consequences on the population and community patterns. feeding behavior of moina micrura, ceriodaphnia dubia and daphnia ambigua (cladocera) on the microalgae chlorella sp. and oocystis sp. (chlorophyceae) was compared by using the following parameters: maximum ingestion rate (imax), incipient limiting concentration (ilc) and consumption efficiency (b), which were obtained through a model of functional response. results indicated that d. ambigua showed the highest imax and ilc on both resources, however, this specie presented the lowest b. whereas, d. ambigua did not show differences in b on chlorella sp. or oocystis sp., m. micrura showed a higher b on chlorella sp. and c. dubia on oocystis sp. these results reveal significant interspecific differences in the feeding response of cladocera, which showed a complex behavior exposed to variations in the availability of food resources
Medical Care Organization to Face Dengue Epidemics
Martinez,Eric;
Revista Cubana de Medicina Tropical , 2009,
Abstract: introduction: dengue is only a disease with a wide clinical spectrum including undifferentiated fever or fever with malaise and general manifestations, and severe dengue, induced mainly by plasma extravasation leading to prolonged or recurrent shock and death. medical care organization during epidemics is crucial to prevent fatalities and includes at least five components: 1. training of medical and nurse personnel. it is an investment that shall be programmed, controlled and evaluated. the time and resources for training must be considered as the equivalent of the expenses in still unavailable vaccines or drugs against dengue. 2. health education. to involve patients and their families in their own care, so that they can be prepared to ask for medical care at the right time, avoid self medication, identify skin bleedings (petechiae), and look for warning signs. 3. classification of every suspected dengue case (triage). a good classification of patients should be simple to be used in every place and should be dynamic to allow changes in treatment. early recognition of warning signs that announce dengue severity and intravenous fluids (crystalloids) given at that very moment can prevent dengue shock and other complications. 4. rearrangement of medical services and warranty of some resources. it is not correct to think that the preparation to face a dengue epidemic will include big amounts of drugs, blood and blood products. the most important resource continues being the human resource. if doctors and nurses are well trained, the prescription of such drugs and procedures will decrease, including platelet transfusion or blood transfusions. 5. research. biomedical and social research are needed, with emphasis on the impact of health education on patients and their families, the natural course of the illness and the best way to do ambulatory treatment. conclusions: the future of the severe dengue cases will be usually decided upon not in the intensive care unit but long
Recherches curriculaires : retour vers le futur
Pierre Martinez
Synergies Chine , 2012,
Abstract: Ce texte vise à exposer sur quels objets peuvent porter les recherches curriculaires et avec quelles méthodes elles peuvent se développer. Pour comprendre une telle problématique, il faut revenir aux conditions dans lesquelles s’est développé le concept, dans le monde anglo-saxon et en Europe actuellement. Des références et des exemples nombreux peuvent aider le lecteur à aller plus loin. Réfléchir au curriculum est de nature à remettre en question les finalités mêmes de nos conceptions éducatives.
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