233 research outputs found
Families of Canonical Transformations by Hamilton-Jacobi-Poincar\'e equation. Application to Rotational and Orbital Motion
The Hamilton-Jacobi equation in the sense of Poincar\'e, i.e. formulated in
the extended phase space and including regularization, is revisited building
canonical transformations with the purpose of Hamiltonian reduction. We
illustrate our approach dealing with orbital and attitude dynamics. Based on
the use of Whittaker and Andoyer symplectic charts, for which all but one
coordinates are cyclic in the Hamilton-Jacobi equation, we provide whole
families of canonical transformations, among which one recognizes the familiar
ones used in orbital and attitude dynamics. In addition, new canonical
transformations are demonstrated.Comment: 21 page
A catalog of natural products occurring in watermelon— Citrullus lanatus
Sweet dessert watermelon ( Citrullus lanatus ) is one of the most important vegetable crops consumed throughout the world. The chemical composition of watermelon provides both high nutritional value and various health benefits. The present manuscript introduces a catalog of 1,679 small molecules occurring in the watermelon and their cheminformatics analysis for diverse features. In this catalog, the phytochemicals are associated with the literature describing their presence in the watermelon plant, and when possible, concentration values in various plant parts (flesh, seeds, leaves, roots, rind). Also cataloged are the chemical classes, molecular weight and formula, chemical structure, and certain physical and chemical properties for each phytochemical. In our view, knowing precisely what is in what we eat, as this catalog does for watermelon, supports both the rationale for certain controlled feeding studies in the field of precision nutrition, and plant breeding efforts for the development of new varieties with enhanced concentrations of specific phytochemicals. Additionally, improved and comprehensive collections of natural products accessible to the public will be especially useful to researchers in nutrition, cheminformatics, bioinformatics, and drug development, among other disciplines
Supersymmetric Branes on AdS_5 x Y^{p,q} and their Field Theory Duals
We systematically study supersymmetric embeddings of D-brane probes of
different dimensionality in the AdS_5xY^{p,q} background of type IIB string
theory. The main technique employed is the kappa symmetry of the probe's
worldvolume theory. In the case of D3-branes, we recover the known three-cycles
dual to the dibaryonic operators of the gauge theory and we also find a new
family of supersymmetric embeddings. The BPS fluctuations of dibaryons are
analyzed and shown to match the gauge theory results. Supersymmetric
configurations of D5-branes, representing domain walls, and of spacetime
filling D7-branes (which can be used to add flavor) are also found. We also
study the baryon vertex and some other embeddings which break supersymmetry but
are nevertheless stable.Comment: LaTeX, 2 figures, 54 pages; v2: discussions sharpened at several
points, new subsection and references adde
High-level of viral genomic diversity in cervical cancers: a Brazilian study on human papillomavirus type 16
Invasive cervical cancer (ICC) is the third most frequent cancer among women worldwide and is associated with persistent infection by carcinogenic human papillomaviruses (HPVs). The combination of large populations of viral progeny and decades of sustained infection may allow for the generation of intra-patient diversity, in spite of the assumedly low mutation rates of PVs. While the natural history of chronic HPVs infections has been comprehensively described, within-host viral diversity remains largely unexplored. In this study we have applied next generation sequencing to the analysis of intra-host genetic diversity in ten ICC and one condyloma cases associated to single HPV16 infection. We retrieved from all cases near full-length genomic sequences. All samples analyzed contained polymorphic sites, ranging from 3 to 125 polymorphic positions per genome, and the median probability of a viral genome picked at random to be identical to the consensus sequence in the lesion was only 40%. We have also identified two independent putative duplication events in two samples, spanning the L2 and the L1 gene, respectively. Finally, we have identified with good support a chimera of human and viral DNA. We propose that viral diversity generated during HPVs chronic infection may be fueled by innate and adaptive immune pressures. Further research will be needed to understand the dynamics of viral DNA variability, differentially in benign and malignant lesions, as well as in tissues with differential intensity of immune surveillance. Finally, the impact of intralesion viral diversity on the long-term oncogenic potential may deserve closer attention.Funded by Grants # 2011/24035-2 and # 2012/23290-1, São Paulo Research Foundation (FAPESP
Binding and uptake of H-ferritin are mediated by human transferrin receptor-1
Ferritin is a spherical molecule composed of 24 subunits of two types, ferritin H chain (FHC) and ferritin L chain (FLC). Ferritin stores iron within cells, but it also circulates and binds specifically and saturably to a variety of cell types. For most cell types, this binding can be mediated by ferritin composed only of FHC (HFt) but not by ferritin composed only of FLC (LFt), indicating that binding of ferritin to cells is mediated by FHC but not FLC. By using expression cloning, we identified human transferrin receptor-1 (TfR1) as an important receptor for HFt with little or no binding to LFt. In vitro, HFt can be precipitated by soluble TfR1, showing that this interaction is not dependent on other proteins. Binding of HFt to TfR1 is partially inhibited by diferric transferrin, but it is hindered little, if at all, by HFE. After binding of HFt to TfR1 on the cell surface, HFt enters both endosomes and lysosomes. TfR1 accounts for most, if not all, of the binding of HFt to mitogen-activated T and B cells, circulating reticulocytes, and all cell lines that we have studied. The demonstration that TfR1 can bind HFt as well as Tf raises the possibility that this dual receptor function may coordinate the processing and use of iron by these iron-binding molecules
Analysis of Tumor Metabolism Reveals Mitochondrial Glucose Oxidation in Genetically Diverse Human Glioblastomas in the Mouse Brain In Vivo
SummaryDysregulated metabolism is a hallmark of cancer cell lines, but little is known about the fate of glucose and other nutrients in tumors growing in their native microenvironment. To study tumor metabolism in vivo, we used an orthotopic mouse model of primary human glioblastoma (GBM). We infused 13C-labeled nutrients into mice bearing three independent GBM lines, each with a distinct set of mutations. All three lines displayed glycolysis, as expected for aggressive tumors. They also displayed unexpected metabolic complexity, oxidizing glucose via pyruvate dehydrogenase and the citric acid cycle, and using glucose to supply anaplerosis and other biosynthetic activities. Comparing the tumors to surrounding brain revealed obvious metabolic differences, notably the accumulation of a large glutamine pool within the tumors. Many of these same activities were conserved in cells cultured ex vivo from the tumors. Thus GBM cells utilize mitochondrial glucose oxidation during aggressive tumor growth in vivo
Alguns dados sobre a Fauna entomológica da ilha das Flores - Açores
IV Expedição Científica do Departamento de Biologia - Flores 1989Com este trabalho, realizado em Julho de 1989 nas Flores - a ilha mais ocidental
do Arquipélago dos Açores -, acrescentaram-se onze espécies de Lepidópteros à lista referenciada para aquela ilha, pertencendo uma à família Lycaenidae (Lampides boeticus L.), oito a familia Noctuidae (Agrotis ipsilon HFN., Brotolomia meticulosa L., Chrysodeixis chalcites ESPER., Heliothis armigera HBN., Noctua atlantica WARREN, Noctua pronuba L., Peridroma saucia HBN., Sesamia nonagrioides LEF.), uma à família Nymphalidae (Vanessa atalanta L.) e uma a família Pyralidae (Glyphodes unionalis HBN.). Entre os demais insectos, foram identificadas cerca de duas dezenas e meia de espécies, distribuídas pelas Ordens Dermaptera, Orthoptera, Dictyoptera, Heteroptera, Homoptera, Coleoptera, Neuroptera, Diptera, Hymenoptera e Collembola. Salienta-se ainda a importância, do ponto de vista agronómico, das pragas Mythimna unipuncta (HAWORTH) e Xestia c-nigrun L. naquela ilha.RÉSUMÉ: Avec ce travail, réalisé en Juillet 1989 a Flores - l'île plus occidental de l'archipel des Açores, onze espèces de Lépidoptères ont été ajoutées à la liste des espèces connus pour cette île, dont une appartient a la famille Lycaenidae (Lampides boelicus L.), huit à la famille Noctuidae (Agrotis ipsilon HFN., Brotolomia meticulosa L. Chrysodeicis chalcites ESPER., Heliothis armigera HBN., Noctua atlantica WARREN, Noctua pronuba L., Peridroma saucia HBN., Sesamia nonagrioides LEF.), une à la famille Nymphalidae (Vanessa atalanta L.) et une à la famille Pyralidae (Glyphodes unionalis HBN.). Parmi les autres insects ont été identifiés environ deux dizaines et demie d'espèces, lesquelles sont réparties par les Ordres Dermaptera, Orthoptera, Dictyoptera, Heteroptera, Homoptera, Coleoptera, Neuroptera, Diptera, Hymenoptera et Collembola. On remarque I'importance, du point de vue agronomique, des ravageurs Mythimna unipuncra (HAWORTH) et Xestia c-nigrum L. dans cette île
Modelo de quatro forças para alavancagem da sustentabilidade de empresas do setor da construção civil
O presente trabalho aplica o Modelo de Quatro Forças para analisar como transformar o desenvolvimento de uma organização de um modelo insustentável para um modelo sustentável, focado no aspecto ambiental, mas sem desconsiderar os aspectos econômico e social. Para seu desenvolvimento, foi realizada pesquisa bibliográfica e exploratória em um estudo de caso sobre a análise de maturidade em sustentabilidade de uma empresa do setor de construção civil, como diagnóstico da situação atual da empresa. Foram utilizadas as análises obtidas no estudo de caso para aplicação do Modelo de Quatro Forças e, como resultado, foi elaborada uma proposta de priorização das ações de melhoria para tornar o desenvolvimento da empresa sustentáve
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Inflation and Dark Energy from spectroscopy at z > 2
The expansion of the Universe is understood to have accelerated during two
epochs: in its very first moments during a period of Inflation and much more
recently, at z < 1, when Dark Energy is hypothesized to drive cosmic
acceleration. The undiscovered mechanisms behind these two epochs represent
some of the most important open problems in fundamental physics. The large
cosmological volume at 2 < z < 5, together with the ability to efficiently
target high- galaxies with known techniques, enables large gains in the
study of Inflation and Dark Energy. A future spectroscopic survey can test the
Gaussianity of the initial conditions up to a factor of ~50 better than our
current bounds, crossing the crucial theoretical threshold of
of order unity that separates single field and
multi-field models. Simultaneously, it can measure the fraction of Dark Energy
at the percent level up to , thus serving as an unprecedented test of
the standard model and opening up a tremendous discovery space
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