Most aspects of agriculture in Cuba prior to 1989 were comparable to California: a high energy input, conventional agriculture (based on what the Cubans now call the “classical model”) in which little was done to protect the nation's soils from erosion, loss of fertility, salinization, and other forms of degradation. In stark contrast the new “Alternative Model,” which has been rapidly replacing the previous model since 1989, emphasizes soil conservation and rehabilitation and the general improvement of the nation's soils as (...) the key to sustaining low-input production and attainment of food security. One of the first steps in implementing the new model was the launching of an ambitious program to reclassify, evaluate, and map the nation's soils in great detail, and to interpret the maps for management of sustainable production. A main feature of this program is coordinated fertility trials to determine, for each combination of crop and soil, the minimum quantity of plant nutrients needed to produce the crop. The build up and maintenance of soil fertility and productivity is being accomplished with various organic and mineral amendments and biofertilizers, produced or mined within the country (locally, where possible) and through rational management utilizing cover crops, green manures, crop successions (intercropping and rotations), and other appropriate technologies. Rehabilitation of degraded soils, tillage reduction, reforestation, vermiculture, vermicomposting, and other forms of waste cycling are other features of the new model that are important to soil conservation and maintenance for sustainable production. (shrink)

In Computer Science stepwise refinement of algebraic specifications is a well-known formal methodology for rigorous program development. This paper illustrates how techniques from Algebraic Logic, in particular that of interpretation, understood as a multifunction that preserves and reflects logical consequence, capture a number of relevant transformations in the context of software design, reuse, and adaptation, difficult to deal with in classical approaches. Examples include data encapsulation and the decomposition of operations into atomic transactions. But if interpretations open such a new (...) research avenue in program refinement, (conceptual) tools are needed to reason about them. In this line, the paper’s main contribution is a study of the correspondence between logical interpretations and morphisms of a particular kind of coalgebras. This opens way to the use of coalgebraic constructions, such as simulation and bisimulation, in the study of interpretations between (abstract) logics. (shrink)

A solution of the sourceless Einstein's equation with an infinite value for the cosmological constant Λ is discussed by using Inönü–Wigner contractions of the de Sitter groups and spaces. When Λ→∞, spacetime becomes a four-dimensional cone, dual to Minkowski space by a spacetime inversion. This inversion relates the four-cone vertex to the infinity of Minkowski space, and the four-cone infinity to the Minkowski light-cone. The non-relativistic limit c→∞ is further considered, the kinematical group in this case being a modified Galilei (...) group in which the space and time translations are replaced by the non-relativistic limits of the corresponding proper conformal transformations. This group presents the same abstract Lie algebra as the Galilei group and can be named the conformal Galilei group. The results may be of interest to the early Universe Cosmology. (shrink)

The psychological state and neural correlates of 19 women undergoing normal childbirth were studied. Frequent occurence of nonordinary psychological phenomena was traced back in 6 subjects, occurring in active and passive alertness, as well as hypnagogic/hypnopompic periods, and in dreaming, during the late period of pregnancy, giving birth, and the period of 2-4 days post partull. The brain activity of the aforementioned subgroup during this time was characterized primarily by general activation of the right hemisphere in the bandpass of infraslow (...) electrical processes and by more localized EEG activation. The implications of the data for research on gender-specific altered states of consciousness are discussed. (shrink)

The cognitive and behavioral functions of the frontal lobes have been of great interest to neuroscientists, neurologists, psychologists and psychiatrists. Recent technical advances have made it possible to trace their neuroanatomical connections more precisely and to conduct evoked potential and neuroimaging studies in patients. This book presents a broad and authoritative synthesis of research progress in this field. It encompasses neuroanatomical studies; experiments involving temporal organization and working memory tasks in non-human primates; clinical studies of patients following frontal lobe excisions (...) for intractable epilepsy; metabolic imaging in schizophrenia and affective disorder; neurobehavioral studies of patients with dementia, frontal lobe tumors, and head injuries; magnetic resonance imaging methods for studying human frontal lobe anatomy; theoretical approaches to describing frontal lobe functions; and rehabilitation of patients with frontal lobe damage including their core problem of diminished awareness. Written by a distinguished group of neuroscientists, psychologists and clinicians, Frontal Lobe Function and Dysfunction provides the best current source of information on this region of the brain and its role in cognition, behavior and clinical disorders. (shrink)

O objetivo do artigo é colocar em evidência algumas disputas em torno da identidade da educação infantil, explorando como tema central os processos de construção e implementação da Base Nacional Comum Curricular para a primeira etapa da educação básica. Para contextualizar nossa argumentação, colocamos a Base em diálogo com outras mudanças no campo das políticas educacionais, que incidem sobre a organização curricular, tais como o Documento Referência para o Sistema de Avaliação da Educação Básica, a Política Nacional de Alfabetização e (...) a Base Nacional Comum para Formação de Professores da Educação Básica, orientações ou normativas que visam produzir definições curriculares, com desdobramentos para a educação das crianças da creche e/ou da pré-escola. A metodologia contemplou revisão bibliográfica e análise documental, incluindo os documentos orientadores para as políticas elaborados pelo Ministério da Educação e o ordenamento legal recente do país. A revisão da literatura aponta no sentido de que grupos de interesse mercantil transnacionais ganham cada vez mais espaço na formulação de políticas educacionais no Brasil, juntamente com outros coletivos ligados a matrizes neoconservadoras e anticientíficas. As repercussões para a organização da oferta de educação infantil são analisadas a partir de estudos que tematizam as especificidades curriculares da educação de crianças de até seis anos, questionando o uso de modelos padronizados de educação, propostas uniformizadas para a formação de docentes e a realização de avaliações em larga escala. Dada à exigência legal de implementação da Base, argumentamos sobre a importância dos movimentos de leitura desse documento a serem realizados nos espaços voltados à formação continuada em serviço no nível local. Essa seria uma condição para efetivar a construção e vivência de currículos mais contextualizados, pensados a partir do documento nacional, mas avançando para além desse, no sentido de garantir um protagonismo das equipes profissionais e colocar crianças concretas no centro do processo de planejamento, promovendo práticas cotidianas em maior consonância com os direitos de aprendizagem e de desenvolvimento, em diálogo com as Diretrizes Curriculares Nacionais para a Educação Infantil. Palavras-chave : Educação Infantil. Base. Política Curricular. Formação Continuada. (shrink)

Jean Philiponus est un théologien monophysite du VIe siècle qui a commenté le De Anima d'Aristote. Il suit le traitement d'Aristote au sujet de la vue et de la lumière. Il se demande si l'oeil est purement un récepteur passif de lumière ou si il est un émetteur de rayons visuels en interaction avec l'objet et de ce fait rend la vision possible. Jean Philiponus en arrive à une nouvelle théorie de la vision où celle-ci apparaît comme une faculté en (...) interaction avec ce qui est vu en raison de la nature non corporelle de la lumière. On est ici au tout début de la controverse sur les images. (shrink)