4,056 research outputs found
Analysis of Neighbourhoods in Multi-layered Dynamic Social Networks
Social networks existing among employees, customers or users of various IT
systems have become one of the research areas of growing importance. A social
network consists of nodes - social entities and edges linking pairs of nodes.
In regular, one-layered social networks, two nodes - i.e. people are connected
with a single edge whereas in the multi-layered social networks, there may be
many links of different types for a pair of nodes. Nowadays data about people
and their interactions, which exists in all social media, provides information
about many different types of relationships within one network. Analysing this
data one can obtain knowledge not only about the structure and characteristics
of the network but also gain understanding about semantic of human relations.
Are they direct or not? Do people tend to sustain single or multiple relations
with a given person? What types of communication is the most important for
them? Answers to these and more questions enable us to draw conclusions about
semantic of human interactions. Unfortunately, most of the methods used for
social network analysis (SNA) may be applied only to one-layered social
networks. Thus, some new structural measures for multi-layered social networks
are proposed in the paper, in particular: cross-layer clustering coefficient,
cross-layer degree centrality and various versions of multi-layered degree
centralities. Authors also investigated the dynamics of multi-layered
neighbourhood for five different layers within the social network. The
evaluation of the presented concepts on the real-world dataset is presented.
The measures proposed in the paper may directly be used to various methods for
collective classification, in which nodes are assigned to labels according to
their structural input features.Comment: 16 pages, International Journal of Computational Intelligence System
A Detection Method for Tropical Race 4 of the Banana Pathogen Fusarium oxysporum f. sp. cubense
Fusarium oxysporum f. sp. cubense (Foc) is the causal agent of Fusarium wilt, the devastating disease that ruined the âGros Michelâ (AAA)-based banana production in the first half of the 20th century. The occurrence of a new variant in Southeast Asia that overcomes the resistance in Cavendish clones such as âGrand Naineâ (AAA) is a major concern to current banana production worldwide. The threat posed by this new variant, called tropical race 4 (TR4), may be overcome by the introduction of resistant cultivars. However, the identification of new resistant sources or breeding for resistance is a long-term effort. Currently, the only option to control the disease is to avoid or reduce the spread of the pathogen by eradication of infected plants and isolation of infested plantations. This requires sensitive and highly specific diagnostics that enable early detection of the pathogen. A two-locus database of DNA sequences, from over 800 different isolates from multiple formae speciales of F. oxysporum, was used to develop a molecular diagnostic tool that specifically detects isolates from the vegetative compatibility group (VCG) 01213, which encompasses the Foc TR4 genotype. This diagnostic tool was able to detect all Foc TR4 isolates tested, while none of the Foc isolates from 19 VCGs other than 01213 showed any reaction. In addition, the developed diagnostic tool was able to detect Foc TR4 when using DNA samples from different tissues of âGrand Naineâ plants inoculated with TR4 isolate
A molecular diagnostic for tropical race 4 of the banana
This study analysed genomic variation of the translation elongation factor 1 (TEF-1) and the intergenic spacer region (IGS) of the nuclear ribosomal operon of Fusarium oxysporum f. sp. cubense (Foc) isolates, from different banana production areas, representing strains within the known races, comprising 20 vegetative compatibility groups
Hydrostatic Stokes Equations With Non-smooth Date For Mixed Boundary Conditions
The main subject of this work is to study the concept of very weak solution for the hydrostatic Stokes system with mixed boundary conditions (non-smooth Neumann conditions on the rigid surface and homogeneous Dirichlet conditions elsewhere on the boundary). In the Stokes framework, this concept has been studied by Conca [Rev. Mat. Apl. 10 (1989)] imposing non-smooth Dirichlet boundary conditions. In this paper, we introduce the dual problem that turns out to be a hydrostatic Stokes system with non-free divergence condition. First, we obtain strong regularity for this dual problem (which can be viewed as a generalisation of the regularity results for the hydrostatic Stokes system with free divergence condition obtained by Ziane [Appl. Anal. 58 (1995)]). Afterwards, we prove existence and uniqueness of very weak solution for the (primal) problem. As a consequence of this result, the existence of strong solution for the non-stationary hydrostatic Navier-Stokes equations is proved, weakening the hypothesis over the time derivative of the wind stress tensor imposed by GuillĂ©n-GonzĂĄlez, Masmoudi and RodrĂguez-Bellido [Differential Integral Equations 50 (2001)]. © 2004 Elsevier SAS. All rights reserved.216807826Amrouche, C., Girault, V., Decomposition of vector spaces and application to the Stokes problem in arbitrary dimension (1994) Czechoslovak Math. J., 44 (119), pp. 109-140AzĂ©rad, P., GuillĂ©n, F., Mathematical justification of the hydrostatic approximation in the Primitive Equations of qeophysical fluid dynamics (2001) SIAM J. Math. Anal., 33 (4), pp. 847-859Besson, O., Laydi, M.R., Some estimates for the anisotropic Navier-Stokes equations and for the hydrostatic approximation (1992) M2AN-Mod. Math. Ana. Nume., 7, pp. 855-865Cattabriga, L., Sur un problema al contorno relativo al sistema di equazioni di Stokes (1961) Rend. Mat. Sem. Univ. Padova, 31, pp. 308-340ChacĂłn, T., GuillĂ©n, F., An intrinsic analysis of existence of solutions for the hydrostatic approximation of the Navier-Stokes equations (2000) C. R. Acad. Sci. Paris, SĂ©rie I, 330, pp. 841-846Conca, C., Stokes equations with non-smooth data (1989) Revista de MatemĂĄticas Aplicadas, 10, pp. 115-122Girault, V., Raviart, P.A., (1986) Finite Element Methods for Navier-Stokes Equations, , Berlin: Springer-VerlagGuillĂ©n-GonzĂĄlez, F., RodrĂguez-Bellido, M.A., On the strong solutions of the Primitive Equations in 2D domains (2002) Nonlin. Anal., 50, pp. 621-646GuillĂ©n-GonzĂĄlez, F., Masmoudi, N., RodrĂguez-Bellido, M.A., Anisotropic estimates and strong solutions of the Primitive Equations (2001) Differential Integral Equations, 14 (11), pp. 1381-1408Lewandowski, R., (1997) Analyse MathĂ©matique et OcĂ©anographie, , MassonLions, J.L., Magenes, E., (1969) ProblĂšmes aux Limites Non HomogĂšnes et Applications, 1. , Paris: DunodLions, J.L., Temam, R., Wang, S., New formulation of the primitive equations of the atmosphere and applications (1992) Nonlinearity, 5, pp. 237-288Lions, J.L., Temam, R., Wang, S., On the equations of the large scale ocean (1992) Nonlinearity, 5, pp. 1007-1053Pedlosky, J., (1987) Geophysical Fluid Dynamics, , Berlin: Springer-VerlagTemam, R., (1977) Navier-Stokes Equations: Theory and Numerical Analysis, , Amsterdam: North HollandZiane, M., Regularity results for Stokes type systems (1995) Appl. Anal., 58, pp. 263-29
Quantitative Analysis of the Publishing Landscape in High-Energy Physics
World-wide collaboration in high-energy physics (HEP) is a tradition which
dates back several decades, with scientific publications mostly coauthored by
scientists from different countries. This coauthorship phenomenon makes it
difficult to identify precisely the ``share'' of each country in HEP scientific
production. One year's worth of HEP scientific articles published in
peer-reviewed journals is analysed and their authors are uniquely assigned to
countries. This method allows the first correct estimation on a ``pro rata''
basis of the share of HEP scientific publishing among several countries and
institutions. The results provide an interesting insight into the geographical
collaborative patterns of the HEP community. The HEP publishing landscape is
further analysed to provide information on the journals favoured by the HEP
community and on the geographical variation of their author bases. These
results provide quantitative input to the ongoing debate on the possible
transition of HEP publishing to an Open Access model.Comment: For a better on-screen viewing experience this paper can also be
obtained at:
http://doc.cern.ch/archive/electronic/cern/preprints/open/open-2006-065.pd
Into the depths of deep eutectic solvents
Ionic liquids (ILs) have been successfully tested in a wide range of applications; however, their high price and complicated synthesis make them infeasible for large scale implementation. A decade ago, a new generation of solvents so called deep eutectic solvents (DESs) was reported for the first time. DESs show similar properties to ILs and they have proven to be an excellent alternative to ILs in many applications where ILs succeeded first. Besides, DESs can be prepared easily and cheaply, with low-cost starting materials, no need of solvents, no atom loss during the formation and no additional purification requirements. The main problem that scientist are facing when they want to use DESs in different applications is the lack of information on the fundamentals of these solvents. Why do they form? How do they form? How do the hydrogen bond donor (HBD) and the hydrogen bond acceptor (HBA) interact? How do DESs interact with other compounds? Can we predict their thermophysical properties? The answer to these questions will provide to researches new insights on the application of these solvents, solving the problem of trial-and-error experimentation. In this work, we present a detailed analysis of molecular interactions and conformational states of two selected DESs: lactic acid â choline chloride (2:1) and glycolic acid â choline chloride (1:1), using density functional theory (DFT) and second-order MĂžllerÂżPlesset perturbation theory (MP2) with various basis sets. Theoretical calculations were performed using the GAUSSIAN 03 software package. The obtained results are used to evaluate the nature of interactions between the HBD and HBA and their structural features. Additionally, it will contribute to the better understanding of how DESs are formed
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Mapping Texas
textThe evolution of scientific reasoning and its practice today is noticeable to say the least. Access to the Internet exemplifies how technologies redefine the speed, access and interaction with information. In cartography, innovations at the turn of the twenty-first century travel alongside the growth of computation and the Internet, particularly in the graphic presentation and reproduction of maps. The Internet has molded cartographic practices to advance the virtual representation of space, a tool bounding potential voters for political ends. Simply, they provide a platform to make populations legible to the point of immediacy. The method of this thesis is to get entrenched in the fiction of Texas. Fiction, here, is interchangeable with the idea of social constructions. It is an attempt to build off the approach of Walter Benjamin, as described in Susan Buck Morris's The Dialetics of Seeing (1989) where consumers get engulfed in a dream world with the commodities that makes their relation to society more personal. The commodity of interest for this work is that of maps. Accordingly, this work builds its analysis on the fiction that makes up the Texas story, as told by maps and cartography. In addition, fiction itself is specifically theorized in analyzing the field of demography and cities in Texas. In conclusion, in calling for critical thought, particularly feminist thought, modern mapping practices are presented to help provide voters an empowering lens in relation to electoral mapping.Latin American Studie
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Direct-Write Fabrication of Integrated, Multilayer Ceramic Components
The need for advanced (electronic) ceramic components with smaller size, greater
functionality, and enhanced reliability requires the ability to integrate electronic ceramics in
complex 3-D architectures. For rapid prototyping and small-lot manufacturing, traditional tape
casting and screen printing approaches are poorly suited. To address this need, we are developing
a direct-write approach for fabricating highly integrated, multilayer components using a
micropen to deposit slurries in precise patterns. With this technique, components can be
constructed layer by layer, simplifying fabrication. It can also be used to produce structures
combining several materials in a single layer. The parts are either cofired or sequentially fired,
after each layer is deposited. Since differential shrinkage can lead to defects in these multilayer
structures, we are characterizing the sintering behavior ofindividua1layers. This technique has
been used to fabricate devices such integrated RC filters, multilayer voltage transformers, and
other passive components. The direct-write approach provides the ability to fabricate
multifunctional, multimaterial integrated ceramic components (MMICCs) in an agile and rapid
way.Mechanical Engineerin
Nigrosine staining of wheat endosperm proteolipid patterns on starch gels
We have previously characterized a group of proteolipids from wheat endosperm, designated CM proteins, which are soluble in chloroformmethanol (2:1, v/v) and have a molecular weight lower than 25,000 daltons (1-3). These have been also studied by Redman and Ewart (4). The CM proteins are suitably fractionated into several components by starch gel electrophoresis at pH 3.2 (1). A sensitive staining procedure was required in connection with genetic studies of these proteins because phenotypes had to be ascertained in small endosperm fractions dissected without impairing normal germination and plant development. We report here on Nigrosine staining conditions for CM proteins under which high sensitivity and selectivity are achieve
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