Two major groups of chloroplast DNA haplotypes in diploid and tetraploid Aconitum subgen : Aconitum (Ranunculaceae) in the Carpathians

Aconitum in Europe is represented by ca. 10% of the total number of species and the Carpathian Mts. are the center of the genus variability in the subcontinent. We studied the chloroplast DNA intergenic spacer trnL(UAG)-rpl32-ndhF (cpDNA) variability of the Aconitum subgen. Aconitum in the Carpathians: diploids (2n=16, sect. Cammarum), tetraploids (2n=32, sect. Aconitum) and triploids (2n=24, nothosect. Acomarum). Altogether 25 Aconitum accessions representing the whole taxonomic variability of the subgenus were sequenced and subjected to phylogenetic analyses. Both parsimony, Bayesian and character network analyses showed the two distinct types of the cpDNA chloroplast, one typical of the diploid and the second of the tetraploid groups. Some specimens had identical cpDNA sequences (haplotypes) and scattered across the whole mountain arch. In the sect. Aconitum 9 specimens shared one haplotype, while in the sect. Camarum one haplotype represents 4 accessions and the second –accessions. The diploids and tetraploids were diverged by 6 mutations, while the intrasectional variability amounted maximally to 3 polymorphisms. Taking into consideration different types of cpDNA haplotypes and ecological profiles of the sections (tetraploids – high-mountain species, diploids – species from forest montane belt) we speculate on the different and independent history of the sections in the Carpathians

Multidimensional Pattern Formation Has an Infinite Number of Constants of Motion

Extending our previous work on 2D growth for the Laplace equation we study here {\it multidimensional} growth for {\it arbitrary elliptic} equations, describing inhomogeneous and anisotropic pattern formations processes. We find that these nonlinear processes are governed by an infinite number of conservation laws. Moreover, in many cases {\it all dynamics of the interface can be reduced to the linear time--dependence of only one ``moment" $M_0$} which corresponds to the changing volume while {\it all higher moments, $M_l$, are constant in time. These moments have a purely geometrical nature}, and thus carry information about the moving shape. These conserved quantities (eqs.~(7) and (8) of this article) are interpreted as coefficients of the multipole expansion of the Newtonian potential created by the mass uniformly occupying the domain enclosing the moving interface. Thus the question of how to recover the moving shape using these conserved quantities is reduced to the classical inverse potential problem of reconstructing the shape of a body from its exterior gravitational potential. Our results also suggest the possibility of controlling a moving interface by appropriate varying the location and strength of sources and sinks.Comment: CYCLER Paper 93feb00

Search strategies of Wikipedia readers

The quest for information is one of the most common activity of human beings. Despite the the impressive progress of search engines, not to miss the needed piece of information could be still very tough, as well as to acquire specific competences and knowledge by shaping and following the proper learning paths. Indeed, the need to find sensible paths in information networks is one of the biggest challenges of our societies and, to effectively address it, it is important to investigate the strategies adopted by human users to cope with the cognitive bottleneck of finding their way in a growing sea of information. Here we focus on the case of Wikipedia and investigate a recently released dataset about users’ click on the English Wikipedia, namely the English Wikipedia Clickstream. We perform a semantically charged analysis to uncover the general patterns followed by information seekers in the multi-dimensional space of Wikipedia topics/categories. We discover the existence of well defined strategies in which users tend to start from very general, i.e., semantically broad, pages and progressively narrow down the scope of their navigation, while keeping a growing semantic coherence. This is unlike strategies associated to tasks with predefined search goals, namely the case of the Wikispeedia game. In this case users first move from the ‘particular’ to the ‘universal’ before focusing down again to the required target. The clear picture offered here represents a very important stepping stone towards a better design of information networks and recommendation strategies, as well as the construction of radically new learning paths

Harmonic moment dynamics in Laplacian growth

Harmonic moments are integrals of integer powers of z = x+iy over a domain. Here the domain is an exterior of a bubble of air growing in an oil layer between two horizontal closely spaced plates. Harmonic moments are a natural basis for such Laplacian growth phenomena because, unlike other representations, these moments linearize the zero surface tension problem (Richardson, 1972), so that all moments except the lowest one are conserved in time. For non-zero surface tension, we show that the the harmonic moments decay in time rather than exhibiting the divergences of other representations. Our laboratory observations confirm the theoretical predictions and demonstrate that an interface dynamics description in terms of harmonic moments is physically realizable and robust. In addition, by extending the theory to include surface tension, we obtain from measurements of the time evolution of the harmonic moments a value for the surface tension that is within 20% of the accepted value.Comment: 10 pages, 7 figure

Novel PHB/PCL scaffolds produced by melt base technologies

[Excerpt] On this work, the natural origin polymer Polyhydroxybutyrate (PHB) was melt blended with synthetic aliphatic polyester Polye-caprolactone (PCL). The ratio of PHB/PCL was varied from 25% to 75% by weight. These blends were further injection moulded and characterized. The thermal properties of the developed blends were accessed by differential scanning calorimetry DSC). The effect of the ratio PHB/PCL on the mechanical properties (tensile modulus and tensile strength) was determined by tensile tests. […]info:eu-repo/semantics/publishedVersio

Projeto interdisciplinar: por dentro da Copa

O Projeto interdisciplinar desenvolvido com alunos da Alfabetização Ciclo Básico I de 6 e 7 anos, visou tomar ciência do evento mundial – Copa do Mundo 2010 – disseminado pela mídia e que interfere na rotina escolar, devido se tratar de um esporte tipicamente brasileiro. O projeto abordou Geografia (localização no globo terrestre), História (África e Brasil), Ciência (animais), Cultura (hábitos, costumes e características), Linguagem (língua e escrita / alfabetização contextualizada / Música), Pesquisas, Trabalho em equipe, Valores, Racismo, Jogos e Recreação. Como prática social finalizadora avaliou-se o conhecimento e as formas de pensar e agir de outras culturas. Observou-se o conhecimento da diversidade do reino animal, conhecimento e utilização de vários suportes de circulação social da escrita (biografias, narrativas, notícias, bilhetes, e-mails, cartas, blogs, ritmos musicais, etc.), reconhecimento dos meios de comunicação para a circulação da notícia, compreensão da importância do respeito, tolerância e união diante de um evento mundial que une povos de diferentes culturas. A culminância se realizou com a aula-passeio ao Horto Municipal de Volta Redonda para a observação de animais abordados na área de ciências; também com uma Exposição de trabalhos realizados durante o Projeto em forma de teatro, músicas, danças e textos. Este Projeto é parte das reflexões sobre a prática didático-pedagógica na pesquisa dissertativa: “Musicalização Infantil: Formação Docente para Educação Ambiental”, cujas ferramentas didáticas contribuem para a aprendizagem significativa critica (MOREIRA, 2010)

Functional and Biogenetical Heterogeneity of the Inner Membrane of Rat-Liver Mitochondria

Rat liver mitochondria were fragmented by a combined technique of swelling, shrinking, and sonication. Fragments of inner membrane were separated by density gradient centrifugation. They differed in several respects: electronmicroscopic appearance, phospholipid and cytochrome contents, electrophoretic behaviour of proteins and enzymatic activities. Three types of inner membrane fractions were isolated. The first type is characterized by a high activity of metal chelatase, low activities of succinate-cytochrome c reductase and of glycerolphosphate dehydrogenase, as well as by a high phospholipid content and low contents of cytochromes aa3 and b. The second type displays maximal activities of glycerolphosphate dehydrogenase and metal chelatase, but contains relatively little cytochromes and has low succinate-cytochrome c reductase activity. The third type exhibits highest succinate-cytochrome c reductase activity, a high metal chelatase activity and highest cytochrome contents. However, this fraction was low in both glycerolphosphate dehydrogenase activity and phospholipid content. This fraction was also richest in the following enzyme activities: cytochrome oxidase, oligomycin-sensitive ATPase, proline oxidase, 3-hydroxybutyrate dehydrogenase and rotenone-sensitive NADH-cytochrome c reductase. Amino acid incorporation in vitro and in vivo in the presence of cycloheximide occurs predominantly into inner membrane fractions from the second type. These data suggest that the inner membrane is composed of differently organized parts, and that polypeptides synthesized by mitochondrial ribosomes are integrated into specific parts of the inner membrane

Random Matrices in 2D, Laplacian Growth and Operator Theory

Since it was first applied to the study of nuclear interactions by Wigner and Dyson, almost 60 years ago, Random Matrix Theory (RMT) has developed into a field of its own within applied mathematics, and is now essential to many parts of theoretical physics, from condensed matter to high energy. The fundamental results obtained so far rely mostly on the theory of random matrices in one dimension (the dimensionality of the spectrum, or equilibrium probability density). In the last few years, this theory has been extended to the case where the spectrum is two-dimensional, or even fractal, with dimensions between 1 and 2. In this article, we review these recent developments and indicate some physical problems where the theory can be applied.Comment: 88 pages, 8 figure

Estimation of Relevant Variables on High-Dimensional Biological Patterns Using Iterated Weighted Kernel Functions

BACKGROUND The analysis of complex proteomic and genomic profiles involves the identification of significant markers within a set of hundreds or even thousands of variables that represent a high-dimensional problem space. The occurrence of noise, redundancy or combinatorial interactions in the profile makes the selection of relevant variables harder. METHODOLOGY/PRINCIPAL FINDINGS Here we propose a method to select variables based on estimated relevance to hidden patterns. Our method combines a weighted-kernel discriminant with an iterative stochastic probability estimation algorithm to discover the relevance distribution over the set of variables. We verified the ability of our method to select predefined relevant variables in synthetic proteome-like data and then assessed its performance on biological high-dimensional problems. Experiments were run on serum proteomic datasets of infectious diseases. The resulting variable subsets achieved classification accuracies of 99% on Human African Trypanosomiasis, 91% on Tuberculosis, and 91% on Malaria serum proteomic profiles with fewer than 20% of variables selected. Our method scaled-up to dimensionalities of much higher orders of magnitude as shown with gene expression microarray datasets in which we obtained classification accuracies close to 90% with fewer than 1% of the total number of variables. CONCLUSIONS Our method consistently found relevant variables attaining high classification accuracies across synthetic and biological datasets. Notably, it yielded very compact subsets compared to the original number of variables, which should simplify downstream biological experimentation