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Search Results: 1 - 10 of 586749 matches for " R. J. D’Souza "
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Discovery of Frequent Closed Itemsets using Reduced Pattern Count Tree
Geetha M,R.J. D'Souza
Lecture Notes in Engineering and Computer Science , 2008,
Abstract:
Significance of Eigenvector Centrality for Routing in a Delay Tolerant Network
R. J. DSouza,Johny Jose
Journal of Computations & Modelling , 2011,
Abstract: Centrality measure is an important concept in networks. It indicates the relative importance of nodes in a network. Various centrality measures have been proposed in the literature, such as degree centrality, closeness centrality etc. Practically all these measures are some values based on the properties of the node concerned. Eigenvector centrality takes into account the centrality value of the neighbours of a node to assign a centrality value to it. In this paper, we show how this value can be utilized to select relay nodes in a delay tolerant network and improve the delivery delay.
Quantitative analysis of heavy mineral in the adjacent continental shelf to the center-north coast of the Santa Catarina state Análise quantitativa dos minerais pesados na plataforma continental interna adjacente ao litoral centro-norte de Santa Catarina
D. R. Souza,J. G. N. Abreu
Brazilian Journal of Aquatic Science and Technology , 2005,
Abstract: Heavy minerals are detritics material originated from igneous, sedimentary and metamorfic rocks, having specific weight superior to the most common minerals, as quartz and feldspat. Its occurrence in coastal and marine continental deposits allows to infer in regard to the evolution of these environments, outstanding as an important tool for Sedimentology and Estratigrafy. Its provenience and distribution trend contribute for the sedimentologic and mineralogic characterization of the deposicional environment, detailing relative sedimentary aspects to each environment. In petroliferous exploration, they are used in the interpretation of the ambient processes and in the analysis of the sedimentary basins. When found in concentrations higher than 1% in relation to the studied fraction it can became economically viable for the exploration and then they are known as placers. Amongst placers of economic value outstand those of ilmenite, rutile, zircon, monazite and magnetite, concentrating in high-energy environments after the disaggregation of the rocks source. Exist in Santa Catarina continental shelf the need of more detailed studies about the mineral species, its concentrations and its distribution areas. Thus, this studied can give start to a series of researches referent to this mineral good and contributes to the production of important bibliographical references for the Southern-Brazilian Continental Edge. Heavy minerals are detritics material originated from igneous, sedimentary and metamorfic rocks, having specific weight superior to the most common minerals, as quartz and feldspat. Its occurrence in coastal and marine continental deposits allows to infer in regard to the evolution of these environments, outstanding as an important tool for Sedimentology and Estratigrafy. Its provenience and distribution trend contribute for the sedimentologic and mineralogic characterization of the deposicional environment, detailing relative sedimentary aspects to each environment. In petroliferous exploration, they are used in the interpretation of the ambient processes and in the analysis of the sedimentary basins. When found in concentrations higher than 1% in relation to the studied fraction it can became economically viable for the exploration and then they are known as placers. Amongst placers of economic value outstand those of ilmenite, rutile, zircon, monazite and magnetite, concentrating in high-energy environments after the disaggregation of the rocks source. Exist in Santa Catarina continental shelf the need of more detailed studies about the mineral sp
Comparison of excretory-secretory antigen and positive faecal supernatant antigen in the detection of Echinococcus granulosus infection in dogs by CIEP
P. R. Prathiush,K. J. Ananda,Placid E. DSouza
Veterinary World , 2009,
Abstract: Coproantigen detection of Echinococcosis in dogs by counter immunoelectrophoresis was standardized. Adult Echinococcus granulosus worms were obtained from intestine of a necropsied positive dog. Excretory-secretory antigen was prepared by culturing adult worms in Medium 199 (pH 7.4). Faeces of positive dog were collected and fecal supernatant was prepared and used for coproantigen detection. CIEP was carried out using tris-borate buffer (pH 8.0) at a constant current of 8mA/slide for 60 minutes. CIEP detected infection with both the antigens. [Vet World 2009; 2(11.000): 421-422]
Progeroid Syndrome of De Barsy With Hypocalcemic Seizures
J Cheriathu,IE D'souza,LJ John,R El Bahtimi
Journal of Nepal Paediatric Society , 2012, DOI: 10.3126/jnps.v32i2.5993
Abstract: De Barsy et al first reported a rare cutaneo-oculo-cerebral malformation-syndrome now commonly referred as ‘progerioid syndrome of de Barsy’. It is the constellation of progeria-like appearance, cutis laxa, intrauterine growth retardation, corneal clouding and hypotonia. We report a case of Debarsy syndrome in a neonate presented at birth with typical clinical features with hypocalcemic seizures. There are no previous reports among Afghani origin and also first case reported from United Arab Emirates, there have been no reported cases of hypocalcemic seizures. J Nepal Paediatr Soc 2012;32(2):175-177 doi: http://dx.doi.org/10.3126/jnps.v32i2.5993
Parametrizing the Stellar Haloes of Galaxies
R. D'Souza,G. Kauffmann,J. Wang,S. Vegetti
Physics , 2014, DOI: 10.1093/mnras/stu1194
Abstract: We study the stellar haloes of galaxies out to 70-100 kpc as a function of stellar mass and galaxy type by stacking aligned $r$ and $g$ band images from a sample of 45508 galaxies from SDSS DR9 in the redshift range $0.06\,\le\,z\,\le\,0.1$ and in the mass range $10^{10.0} M_{\odot} < M_{*} < 10^{11.4} M_{\odot}$r. We derive surface brightness profiles to a depth of almost $\mu_r \sim 32 \,\mathrm{mag\,arcsec}^{-2}$. We find that the ellipticity of the stellar halo is a function of galaxy stellar mass and that the haloes of high concentration ($C > 2.6$) galaxies are more elliptical than those of low concentration ($C < 2.6$) galaxies. The $g$-$r$ colour profile of high concentration galaxies reveals that the $g$-$r$ colour of the stellar population in the stellar halo is bluer than in the main galaxy, and the colour of the stellar halo is redder for higher mass galaxies. We further demonstrate that the full two-dimensional surface intensity distribution of our galaxy stacks can only be fit through multi-component S\'{e}rsic models. Using the fraction of light in the outer component of the models as a proxy for the fraction of accreted stellar light, we show that this fraction is a function of stellar mass and galaxy type. For high concentration galaxies, the fraction of accreted stellar light rises from $30\%$ to $70\%$ for galaxies in the stellar mass range from $10^{10.0} M_{\odot}$ to $10^{11.4} M_{\odot}$. The fraction of accreted light is much smaller in low concentration systems, increasing from $2\%$ to $25\%$ over the same mass range. This work provides important constraints for the theoretical understanding of the formation of stellar haloes of galaxies.
Evaluation of the Antimicrobial Activity of Stryphnodendron barbatiman against Citrobacter freundii  [PDF]
Nara C. de Souza, Marcio N. Gomes, Rafael R. G. Maciel, Romário J. da Silva, Tarquin F. Trescher, Filipe D. S. Gorza, Graciela C. Pedro, Kennedy C. S. Correa, Marcio C. R. Souza, Josmary R. Silva
Materials Sciences and Applications (MSA) , 2013, DOI: 10.4236/msa.2013.412099
Abstract:

Medicinal plants have been presented as a valuable source of preservation of human health. In special, Stryphnodendron barbatiman has been employed due to its antimicrobial activity. This plant is rich in tannins and has been used in popular medicine for the treatment of gastrointestinal disorder, treatment of lesions, and also as anti-inflammatory microbicide. Citrobacter freundii is a member of the family Enterobacteriaceae and is one of the major causes of opportunistic infections. This microorganism is a bacterium (bacillus) aerobic gram-negative with a length in the range of 1 to 5 mm. C. freundii is commonly found in water, soil, food and occasionally in the gastrointestinal tract of animals and humans. In this paper, we have demonstrated the antibacterial activity of S. barbatiman by observing cellular death by using inhibition halo approach. Atomic force microscopy and FT-IR spectroscopy results suggested that interaction between the main active components of S. barbatiman with cellular wall of C. freundii gives rise to cellular wall damage, and then leads this microorganism to death.

Impact of NO2 horizontal heterogeneity on tropospheric NO2 vertical columns retrieved from satellite, multi-axis differential optical absorption spectroscopy, and in situ measurements
D. Mendolia,R. J. C. D'Souza,G. J. Evans,J. Brook
Atmospheric Measurement Techniques Discussions , 2013, DOI: 10.5194/amtd-6-825-2013
Abstract: Tropospheric NO2 vertical column densities were retrieved for the first time in Toronto, Canada using three methods of differing spatial scales. Remotely-sensed NO2 vertical column densities, retrieved from multi-axis differential optical absorption spectroscopy and satellite remote sensing, were evaluated by comparison with in situ vertical column densities derived using a pair of chemiluminescence monitors situated 0.01 and 0.5 km above ground level. The chemiluminescence measurements were corrected for the influence of NOz, which reduced the NO2 concentrations at 0.01 and 0.5 km by 8 ± 1% and 12 ± 1%, respectively. The average absolute decrease in the chemiluminescence NO2 measurement as a result of this correction was less than 1 ppb. Good correlation was observed between the remotely sensed and in situ NO2 vertical column densities (Pearson R ranging from 0.68 to 0.79), but the in situ vertical column densities were 27% to 55% greater than the remotely-sensed columns. These results indicate that NO2 horizontal heterogeneity strongly impacted the magnitude of the remotely-sensed columns. The in situ columns reflected an urban environment with major traffic sources, while the remotely-sensed NO2 vertical column densities were representative of the region, which included spatial heterogeneity introduced by residential neighbourhoods and Lake Ontario. Despite the difference in absolute values, the reasonable correlation between the vertical column densities determined by three distinct methods increased confidence in the validity of the values provided by each of the methods.
Degree Distribution of Competition-Induced Preferential Attachment Graphs
N. Berger,C. Borgs,J. T. Chayes,R. M. D'Souza,R. D. Kleinberg
Mathematics , 2005,
Abstract: We introduce a family of one-dimensional geometric growth models, constructed iteratively by locally optimizing the tradeoffs between two competing metrics, and show that this family is equivalent to a family of preferential attachment random graph models with upper cutoffs. This is the first explanation of how preferential attachment can arise from a more basic underlying mechanism of local competition. We rigorously determine the degree distribution for the family of random graph models, showing that it obeys a power law up to a finite threshold and decays exponentially above this threshold. We also rigorously analyze a generalized version of our graph process, with two natural parameters, one corresponding to the cutoff and the other a ``fertility'' parameter. We prove that the general model has a power-law degree distribution up to a cutoff, and establish monotonicity of the power as a function of the two parameters. Limiting cases of the general model include the standard preferential attachment model without cutoff and the uniform attachment model.
Competition-Induced Preferential Attachment
N. Berger,C. Borgs,J. T. Chayes,R. M. D'Souza,R. D. Kleinberg
Computer Science , 2004,
Abstract: Models based on preferential attachment have had much success in reproducing the power law degree distributions which seem ubiquitous in both natural and engineered systems. Here, rather than assuming preferential attachment, we give an explanation of how it can arise from a more basic underlying mechanism of competition between opposing forces. We introduce a family of one-dimensional geometric growth models, constructed iteratively by locally optimizing the tradeoffs between two competing metrics. This family admits an equivalent description as a graph process with no reference to the underlying geometry. Moreover, the resulting graph process is shown to be preferential attachment with an upper cutoff. We rigorously determine the degree distribution for the family of random graph models, showing that it obeys a power law up to a finite threshold and decays exponentially above this threshold. We also introduce and rigorously analyze a generalized version of our graph process, with two natural parameters, one corresponding to the cutoff and the other a ``fertility'' parameter. Limiting cases of this process include the standard Barabasi-Albert preferential attachment model and the uniform attachment model. In the general case, we prove that the process has a power law degree distribution up to a cutoff, and establish monotonicity of the power as a function of the two parameters.
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