493 resultados para Smale’s Conjecture


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Este trabajo aborda críticamente los argumentos fundamentales de un sector de teorizaciones y prácticas psicoanalíticas que han sido agrupadas bajo la denominación de "tradición hermenéutica", basándose en dos aspectos: primero, atendiendo a la distancia que dichos argumentos mantienen respecto de la propuesta original de Freud; segundo, analizando los supuestos y valores epistémicos que han orientado (explícita e implícitamente) a tales perspectivas. Posteriormente al abordaje crítico, se conjeturan argumentos tendientes a trascender o reenfocar algunos problemas metodológicos de la investigación y práctica psicoanalítica, tales como la conceptualización y formalización de la acción causal, la validación de las conjeturas (metapsicológicas y clínicas) y el lugar de las formalizaciones teóricas en la clínica

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Understanding the evolutionary history of threatened populations can improve their conservation management. Re-establishment of past but recent gene flow could re-invigorate threatened populations and replenish genetic diversity, necessary for population persistence. One of the four nominal subspecies of the common yellow-tufted honeyeater, Lichenostomus melanops cassidix, is critically endangered despite substantial conservation efforts over 55 years. Using a combination of morphometric, genetic and modelling approaches we tested for its evolutionary distinctiveness and conservation merit. We confirmed that cassidix has at least one morphometric distinction. It also differs genetically from the other subspecies in allele frequencies but not phylogenetically, implying that its evolution was recent. Modelling historical distribution supported the lack of vicariance and suggested a possibility of gene flow among subspecies at least since the late Pleistocene. Multi-locus coalescent analyses indicated that cassidix diverged from its common ancestor with neighbouring subspecies gippslandicus sometime from the mid-Pleistocene to the Holocene, and that it has the smallest historical effective population size of all subspecies. It appears that cassidix diverged from its ancestor with gippslandicus through a combination of drift and local selection. From patterns of genetic subdivision on two spatial scales and morphological variation we concluded that cassidix, gippslandicus and (melanops + meltoni) are diagnosable as subspecies. Low genetic diversity and effective population size of cassidix may translate to low genetic fitness and evolutionary potential, thus managed gene flow from gippslandicus is recommended for its recovery.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El crecimiento de la población puneña durante el siglo XX resulta de la evolución de tres circunstancias centrales. La primera consiste en que la sociedad puneña, especialmente la rural, ha sido, y en buena medida lo es, una sociedad tradicional, es decir, no moderna, preindustrial, con estructura social poco diferenciada, con pautas culturales diferenciales. La otra se relaciona con el proceso de articulación entre esa sociedad tradicional y la moderna, capitalista, extra-puneña. La conjetura es que la consolidación del capitalismo en el Noroeste argentino a partir del último tercio del siglo XIX no desplazó ni reemplazó a la sociedad tradicional: convivió con ella durante décadas generando cambios sustanciales en numerosos aspectos. La tercera tiene que ver con la acción del Estado: al menos durante las primeras décadas del XX operó en el contexto del positivismo, asociado con el concepto de desarrollo no lejano al de progreso. A través del progreso, la sociedad tradicional se transforma en una sociedad racional, secular, con estructuras sociales diferenciadas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Este trabajo aborda críticamente los argumentos fundamentales de un sector de teorizaciones y prácticas psicoanalíticas que han sido agrupadas bajo la denominación de "tradición hermenéutica", basándose en dos aspectos: primero, atendiendo a la distancia que dichos argumentos mantienen respecto de la propuesta original de Freud; segundo, analizando los supuestos y valores epistémicos que han orientado (explícita e implícitamente) a tales perspectivas. Posteriormente al abordaje crítico, se conjeturan argumentos tendientes a trascender o reenfocar algunos problemas metodológicos de la investigación y práctica psicoanalítica, tales como la conceptualización y formalización de la acción causal, la validación de las conjeturas (metapsicológicas y clínicas) y el lugar de las formalizaciones teóricas en la clínica

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El crecimiento de la población puneña durante el siglo XX resulta de la evolución de tres circunstancias centrales. La primera consiste en que la sociedad puneña, especialmente la rural, ha sido, y en buena medida lo es, una sociedad tradicional, es decir, no moderna, preindustrial, con estructura social poco diferenciada, con pautas culturales diferenciales. La otra se relaciona con el proceso de articulación entre esa sociedad tradicional y la moderna, capitalista, extra-puneña. La conjetura es que la consolidación del capitalismo en el Noroeste argentino a partir del último tercio del siglo XIX no desplazó ni reemplazó a la sociedad tradicional: convivió con ella durante décadas generando cambios sustanciales en numerosos aspectos. La tercera tiene que ver con la acción del Estado: al menos durante las primeras décadas del XX operó en el contexto del positivismo, asociado con el concepto de desarrollo no lejano al de progreso. A través del progreso, la sociedad tradicional se transforma en una sociedad racional, secular, con estructuras sociales diferenciadas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Este trabajo aborda críticamente los argumentos fundamentales de un sector de teorizaciones y prácticas psicoanalíticas que han sido agrupadas bajo la denominación de "tradición hermenéutica", basándose en dos aspectos: primero, atendiendo a la distancia que dichos argumentos mantienen respecto de la propuesta original de Freud; segundo, analizando los supuestos y valores epistémicos que han orientado (explícita e implícitamente) a tales perspectivas. Posteriormente al abordaje crítico, se conjeturan argumentos tendientes a trascender o reenfocar algunos problemas metodológicos de la investigación y práctica psicoanalítica, tales como la conceptualización y formalización de la acción causal, la validación de las conjeturas (metapsicológicas y clínicas) y el lugar de las formalizaciones teóricas en la clínica

Relevância:

10.00% 10.00%

Publicador:

Resumo:

International politics affect trade patterns, especially for firms in extractive industries. We construct the firm-level dataset for the U.S. oil-importing companies over 1986-2010 to test whether the state of international relations with the trading partners of the U.S. affect importing behavior of the U.S. firms. To measure "political distance" between the U.S. and her trading partners we use voting records for the UN General Assembly. We find that the U.S. firms, in fact, import significantly less oil from the political opponents of the U.S. Our conjecture is that the decrease in oil imports is mainly driven by large, vertically-integrated U.S. firms that engage in foreign direct investment (FDI) overseas.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

International politics affects oil trade. But why? We construct a firm-level dataset for all U.S. oil-importing companies over 1986-2008 to examine what kinds of firms are more responsive to change in "political distance" between the U.S. and her trading partners, measured by divergence in their UN General Assembly voting patterns. Consistent with previous macro evidence, we first show that individual firms diversify their oil imports politically, even after controlling for unobserved firm heterogeneity. We conjecture that the political pattern of oil imports from these individual firms is driven by hold-up risks, because oil trade is often associated with backward vertical FDI. To test this hold-up risk hypothesis, we investigate heterogeneity in responses by matching transaction-level import data with firm-level worldwide reserves. Our results show that long-run oil import decisions are indeed more elastic for firms with oil reserves overseas than those without, although the reverse is true in the short run. We interpret this empirical regularity as that while firms trade in the spot market can adjust their imports immediately, vertically-integrated firms with investment overseas tend to commit to term contracts in the short run even though they are more responsive to changes in international politics in the long run.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

International politics affects oil trade. But does it affect the oil-exporting developing countries more? We construct a firm-level dataset for all U.S. oil-importing companies over 1986-2008 to examine how these firms respond to changes in "political distance" between the U.S. and her trading partners, measured by divergence in their UN General Assembly voting patterns. Consistent with previous macro evidence, we first show that individual firms diversify their oil imports politically, even after controlling for unobserved firm heterogeneity. We conjecture that the political pattern of oil imports from these individual firms is driven by hold-up risks, because oil trade is often associated with backward vertical FDI. To the extent that developing countries have higher hold-up risks because of their weaker institutions, the political effect on oil trade should be more significant in the developing world. We find that oil import decisions are indeed more elastic when firms import from developing countries, although the reverse is true in the short run. Our results suggest that international politics can affect oil revenue and hence long-term development in the developing world.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper introduces and studies the notion of CLP projection for Constraint Handling Rules (CHR). The CLP projection consists of a naive translation of CHR programs into Constraint Logic Programs (CLP). We show that the CLP projection provides a safe operational and declarative approximation for CHR programs. We demónstrate moreover that a confluent CHR program has a least model, which is precisely equal to the least model of its CLP projection (closing henee a ten year-old conjecture by Abdenader et al.). Finally, we illustrate how the notion of CLP projection can be used in practice to apply CLP analyzers to CHR. In particular, we show results from applying AProVE to prove termination, and CiaoPP to infer both complexity upper bounds and types for CHR programs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We show the existence of sets with n points (n ? 4) for which every convex decomposition contains more than (35/32)n?(3/2) polygons,which refutes the conjecture that for every set of n points there is a convex decomposition with at most n+C polygons. For sets having exactly three extreme pointswe show that more than n+sqr(2(n ? 3))?4 polygons may be necessary to form a convex decomposition.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this work, we demonstrate how it is possible to sharply image multiple object points. The Simultaneous Multiple Surface (SMS) design method has usually been presented as a method to couple N wave-front pairs with N surfaces, but recent findings show that when using N surfaces, we can obtain M image points when Nconjecture that maximal SMS designs are very close to a good solution, hence using them as a starting point for the optimization will lead us faster to a final optical system. We suggest here different optimization strategies which combined with the SMS method are proven to give the best solution. Through the example of imaging with the high aspect ratio, we compare the results obtained optimizing the rotational lens and using a combination of SMS method and optimization, showing that the second approach is giving significantly smaller value of overall RMS spot diameter.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

It is widely conjectured that muscle shortens because portions of myosin molecules (the “cross-bridges”) impel the actin filament to which they transiently attach and that the impulses result from rotation of the cross-bridges. Crystallography indicates that a cross-bridge is articulated–consisting of a globular catalytic/actin-binding domain and a long lever arm that may rotate. Conveniently, a rhodamine probe with detectable attitude can be attached between the globular domain and the lever arm, enabling the observer to tell whether the anchoring region rotates. Well-established signature effects observed in shortening are tension changes resulting from the sudden release or quick stretch of active muscle fibers. In this investigation we found that closely correlated with such tension changes are changes in the attitude of the rhodamine probes. This correlation strongly supports the conjecture about how shortening is achieved.