782 research outputs found
Absence of CD59 in guinea pigs: Analysis of the Cavia porcellus genome suggests the evolution of a CD59 pseudogene
CD59 is a membrane-bound regulatory protein that inhibits the assembly of the terminal membrane attack complex (C5b-9) of complement. From its original discovery in humans almost 30 years ago, CD59 has been characterized in a variety of species, from primates to early vertebrates, such as teleost fish. CD59 is ubiquitous in mammals; however, we have described circumstantial evidence suggesting that guinea pigs (Cavia porcellus) lack CD59, at least on erythrocytes. In this study, we have used a combination of phylogenetic analyses with syntenic alignment of mammalian CD59 genes to identify the only span of genomic DNA in C. porcellus that is homologous to a portion of mammalian CD59 and show that this segment of DNA is not transcribed. We describe a pseudogene sharing homology to exons 2 through 5 of human CD59 present in the C. porcellus genome. This pseudogene was flanked by C. porcellus homologs of two genes, FBXO3 and ORF91, a relationship and orientation that were consistent with other known mammalian CD59 genes. Analysis using RNA sequencing confirmed that this segment of chromosomal DNA was not transcribed. We conclude that guinea pigs lack an intact gene encoding CD59; to our knowledge, this is the first report of a mammalian species that does not express a functional CD59. The pseudogene we describe is likely the product of a genomic deletion event during its evolutionary divergence from other members of the rodent order
Thermal tool in the evaluation of the "pinhão'' (seed of Araucaria angustifolia) starch aimed agroindustrial process.
''Pinhão'' is an important source of food for inhabitants in the subtropical region of South America. Gelatinization temperatures for ''pinhão'' are smaller than for corn and cassava starches, bringing advantages in industrial processes. The ''pinhão'' starches of the 4 different provenances were subjected to dilutions of 1:4, 1:5 e 1:6, in water. The starches were evaluated using DSC to determine gelatinization characteristics of them. The results showed that the source and dilutions have influence in the gelation process of the starch.Edição dos Anais do 7º Simpósio de Análise Térmica, 2015, Bauru
Lack of uniqueness for weak solutions of the incompressible porous media equation
In this work we consider weak solutions of the incompressible 2-D porous
media equation. By using the approach of De Lellis-Sz\'ekelyhidi we prove
non-uniqueness for solutions in in space and time.Comment: 23 pages, 2 fugure
White Blood, Black Gold: The Commodification of Wild Rubber in the Bolivian Amazon, 1870-1920
The Bolivian rubber boom thrived during the 1880 and 1920 decades throughout the Amazonian fluvial network (Madre de Dios, Beni, Purús, Madeira and Beni rivers). The economic potential of rubber quickly became a decisive phenomenon in the social history of Eastern Bolivia, linked with the definitive ocupation of marginal territories, new interethnic relations, national and international migration, taxation, property entitlement, the foundation of cities, the rise of nationalism, the struggle to settle republican frontiers and a novel regional opening to global economy. The boom also encouraged substantial developments in cartography, hidrography, botanics and ethnology. Our goal is to describe the singularities of the rubber-tapping industry in Bolivia and to analyse the representations of “nature” held by rubber tappers of the period: there was indeed a modernist discourse based on the usual ideas of "progress" and "civilization" of the industry opposed to the "wildness", "savagery" and "barbarism" massively attributed to Amazonia, and also a generalized notion of the jungle as a "desert land" open to opportunities for the self-made man. In retrospect, these discourses can certainly reveal a lack of “ecological awareness”. However, a closer analysis of historical sources also shows the existence of voices that were more nuanced and reflexive, and in some cases even dared to point out the limits of extractivism –not only in "ecological" terms but also in reference to the life of the indigenous and creole populations involved in the rubber boom
Resonance-free Region in scattering by a strictly convex obstacle
We prove the existence of a resonance free region in scattering by a strictly
convex obstacle with the Robin boundary condition. More precisely, we show that
the scattering resonances lie below a cubic curve which is the same as in the
case of the Neumann boundary condition. This generalizes earlier results on
cubic poles free regions obtained for the Dirichlet boundary condition.Comment: 29 pages, 2 figure
Dissipative continuous Euler flows
We show the existence of continuous periodic solutions of the 3D
incompressible Euler equations which dissipate the total kinetic energy
Theoretical aspects of the CEBAF 89-009 experiment on inclusive scattering of 4.05 GeV electrons from nuclei
We compare recent CEBAF data on inclusive electron scattering on nuclei with
predictions, based on a relation between structure functions (SF) of a nucleus,
a nucleon and a nucleus of point-nucleons. The latter contains nuclear
dynamics, e.g. binary collision contributions in addition to the asymptotic
limit. The agreement with the data is good, except in low-intensity regions.
Computed ternary collsion contributions appear too small for an explanation. We
perform scaling analyses in Gurvitz's scaling variable and found that for
, ratios of scaling functions for pairs of nuclei differ by less
than 15-20% from 1. Scaling functions for are, for increasing ,
shown to approach a plateau from above. We observe only weak -dependence
in FSI, which in the relevant kinematic region is ascribed to the diffractive
nature of the NN amplitudes appearing in FSI. This renders it difficult to
separate asymptotic from FSI parts and seriously hampers the extraction of
from scaling analyses in a model-independnent fashion.Comment: 11 p. Latex file, 2 ps fig
Relativistic approaches to structure functions of nuclei
We employ a propagator technique to derive a new relativistic 1/\qq
expansion of the structure function of a nucleus, composed of point-nucleons.
We exploit non-relativistic features of low-momentum nucleons in the target and
only treat relativistically the nucleon after absorption of a high-momentum
virtual photon. The new series permits a 3-dimensional reduction of each term
and a formal summation of all Final State Interaction terms. We then show that
a relativistic structure function can be obtained from its non-relativistic
analog by a mere change of a scaling variable and an addition of an energy
shift. We compare the obtained result with an ad hoc generalized
Gersch-Rodriguez-Smith theory, previously used in computations of nuclear
structure functions.Comment: Comparison with data is included, to be published in PRC, Feb. 200
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