An independent estimate of the triple-Pomeron coupling

The value of the important triple-Pomeron coupling is estimated by an unorthodox procedure using the known diffractive parton distribution functions. The result is g_{3P}\simeq 0.2g_N, where g_N is the Pomeron-nucleon coupling. This is in excellent agreement with an independent determination, g_{3P}\simeq 0.2g_N, previously obtained by analysing the available data in the triple-Regge region with absorptive effects taken into account.Comment: 7 pages, 5 figure

HUMUS FLORESTAIS: SINTESE E DIAGNOSTICO DAS INTERRELACÕES VEGETAÇÃO/SOLO

With an essentially ecosystem approach this paper tries to present the problem of the soil organic matter under its most interactive aspect: soil-vegetation interrelationships. The macro-morphological study of the humus type in some forest ecosystems of the intertropical Brazilian coast faced both with dilferent approaches and bibliography resulls about organic matter of forest soils. Thus, the different uses of the humus concept, which perrneates different research, will be clarified to show further ahead our resulls both about the quantitative characteristics of humus layers and their morphological structure in order to classify the humus forms of the Resting and Atlantic forest. The resulls contradict the hypothesis, generally accepted, that in tropical regions the faster recycling of soil organic matter leads to determine humic structures of the mull-like type. The dynamics of the interactive processes arnong litter fall, mineral substrata and decomposer communities (microorganisms and fauna) is analyzed in order to elucidate lhe factors which determine the diversity of the humus form in Brazilian coastal forests.O presente trabalho procura, numa abordagem essencialmente ecossistêmica, resituar o problema da matéria orgânica do solo sob seu aspecto interativo maior: o das interrelações vegetação/solo. O estudo macro-morfológico dos tipos de húmus em alguns ecossistemas de Florestas Costeira Intertropical é situado em relação as diferentes abordagens e resultados da bibliografia sobre matéria orgânica de solos florestais. São, assim, explicitadas as diferentes utilizações da noção de húmus subjacentes a diversas pesquisas, para apresentar posteriormente nossos resultados sobre a estrutura macromorfológica e a classificação de húmus de Restinga e de Floresta Atlântica. Estes resultados contradizem a hipótese geralmente admitida, segundo a qual em região tropical a rápida decomposição dos restos foliares determina estruturas húmicas de tipo mull. A dinâmica do processo interativo entre o substrato mineral, os aportes foliares e os agentes biológicos microrganismos e fauna é analisada, a fim de elucidar os fatores que determinam a diversidade de húmus em florestas costeiras

Probing the Statistical Properties of Unknown Texts: Application to the Voynich Manuscript

While the use of statistical physics methods to analyze large corpora has been useful to unveil many patterns in texts, no comprehensive investigation has been performed on the interdependence between syntactic and semantic factors. In this study we propose a framework for determining whether a text (e.g., written in an unknown alphabet) is compatible with a natural language and to which language it could belong. The approach is based on three types of statistical measurements, i.e. obtained from first-order statistics of word properties in a text, from the topology of complex networks representing texts, and from intermittency concepts where text is treated as a time series. Comparative experiments were performed with the New Testament in 15 different languages and with distinct books in English and Portuguese in order to quantify the dependency of the different measurements on the language and on the story being told in the book. The metrics found to be informative in distinguishing real texts from their shuffled versions include assortativity, degree and selectivity of words. As an illustration, we analyze an undeciphered medieval manuscript known as the Voynich Manuscript. We show that it is mostly compatible with natural languages and incompatible with random texts. We also obtain candidates for keywords of the Voynich Manuscript which could be helpful in the effort of deciphering it. Because we were able to identify statistical measurements that are more dependent on the syntax than on the semantics, the framework may also serve for text analysis in language-dependent applications

Método de pontos interiores barreira logarítmica preditor-corretor especializado para o problema de regressão pela norma Lp

The logaritmie barrier and predictor-corretor interior point methods are applied to the Lp norm fitting problem exploiting the matrix structure in order to obtain an efficient implementation.. The fitting problem has numerous applications in various areas. The 2-norin is very popular, among other reasons, for allowing a direct solution. The 1-norin allows the reduction of the effect of outliers while the ∞-norin provides protection against the worst case. The pnorm allows to think these characteristics in different ways adapting the method to the problem to be solved. The interior point method implementation to be developed is compared with existing methods.Os métodos de pontos interiores barreira logarítmica e preditor-corretor são aplicados ao problema de regressão pela norma Lp com algumas particularidades com o objetivo de obter uma implementação eficiente. O problema de regressão tem inúmeras aplicações em diversas áreas. A norma-2 é muito popular, entre outros motivos, por permitir uma solução direta. Por sua vez, a norma-1 permite reduzir o efeito de pontos discrepantes enquanto que a norma-∞ garante proteção contra o pior caso. A norma-p permite pensar estas características de diferentes formas, adaptando o método ao problema a ser resolvido. A implementação do método de pontos interiores desenvolvida é comparada com métodos existentes.21923

FORMAS DE HUMUS EM ECOSSISTEMAS DE FLORESTA COSTEIRA INTERTROPICAL. 1- A MATA ATLANTICA DE TABULEIROS

The Mata Atlantica ecosystems, located in the north part of Espirito Santo (Linhares) has two humus foons according to the forest type: Mata Alta Forest and Mussununga Forest. In the first case, humus is a mull-like fonn, and in the second, a moder-like humus is present. In the moder humus, 22t/ha corresponding to holorganic horizons- are superposed ou the A horizon, with 500kg/ha of organic nitrogen, while in the mull, this quantity reaches 6t/ha, with 100kg/ha of organic nitrogen. Below-ground pools -A horizon at 0-10cm depth- are similar in the two decomposition systems (10t/ha of organic carbon and700kg/ha of total nitrogen). A marked organic matter accumulation in Mussunnnga forest is essentially linked to the parental soil substrata with a limited clay fraction and very poor nutrieut content. Despite the factors detennining the humus fonns, which are simihlr to temperate forests, Mata Atlântica humus are differentiated by faster recycling of nutrieuts and a high organic-maner turnover.O ecossistema de Mata Atlantica localizado no norte do Espírito Santo (Linhares), apresenta duas fomas de húmus, de acordo com o tipo florestal: Mata Alta e Mata Mussununga. No primeiro caso, observa-se um húmus do tipo mull, enquanto a segunda fitofisionomia apresenta um humus do tipo moder. Nesta forma de humus, encontramos no horizonte holorgânico 22t/ha de matéria orgânica superficial e 500kg/ha de nitrogênio orgânico, enquanto no mull, estes valores alcançam 6t/ha de matéria orgânica superficial e 100kg/ha de nitrogênio orgânico. Com relação ao horizonte A subjacente (0-10cm), as duas áreas são similares nos seus conteúdos de matéria orgânica nitrogênio (10t/ha de carbono orgânico e 700kg/ha de nitrogênio total). Uma marcada acumulação superficial de matéria orgânica na Mata de Mussununga está intimamente relacionada à composição do substrato parental, com uma limitada fração de argila e baixíssimo conteúdo de nutrientes. Apesar dos fatores determinantes das formas húmicas serem semelhantes aos das florestas temperadas, os húmus da Mata Atlântica são diferenciados pela rápida reciclagem de nutrientes e alto" turnover" da matéria orgânica