Jose María Álvarez Rodríguez

Localization of metallothionein in breast carcinomas. An immunohistochemical study

Metallothionein (MT) is a cysteine-rich, low molecular weight protein that binds zinc, copper, and cadmium. It is present in a number of normal cells including hepatocytes particularly during fetal and early postnatal life. It has been suggested that developmental profile of MT is similar to other oncofetal gene products and hence, it could be used as a marker for aggressive tumour behaviour. In order to test that hypothesis, we used a monoclonal antibody to MT and immunohistochemically evaluated formalin-fixed, paraffin-embedded tissues from 79 breast carcinomas. In non-neoplastic breast tissue, a strong nuclear and cytoplasmic staining was observed in myoepithelial cells. Positive staining for MT was present in 35 (44%) of breast carcinomas. In most positive cases, nuclear, or both nuclear and cytoplasmic staining was seen. All positive tumours were invasive ductal carcinomas, including a medullary and a metaplastic carcinoma. None of the mucinous, lobular, or intraductal papillary carcinomas reacted for MT. A statistically significant association was found between MT immunostaining and histological grade (P<0.01) as well as with nuclear grade (P<0.01). We also observed an inverse relationship between MT staining and oestrogen receptor content of tumours (P<0.01). Similarly, a statistically significant association was found between moderate and strong MT immunostainig and decreased overall survival and shorter disease-free survival (P<0.01). MT immunostaining was also predective of a worse prognosis in the subgroup of lymph node negative (P<0.001) and oestrogen receptor negative patients (P<0.01). No statistically significant association was found between MT staining and size of tumour or the presence of lymph node metastasis. We conclude that MT staining may be a useful marker of less differentiated and more aggressive carcinomas of the breast.

Characterization of discontinuities in dielectric waveguides using Schelkunoff's method: application to tapers and transitions

Transitions, tapers and abrupt discontinuities are frequently used between different types of dielectric waveguides. This work presents a theoretical method to analyse the former structures. A modal matching method together with the generalized telegraphists’ equations are used. By using the generalized scattering matrix of two discontinuities, we can find the generalized scattering matrix of the cascaded set. Theoretical results of reflection and transmission coefficients, both module and phase, as well as some measurements are compared with those published by other authors.

Phase constants and scattering electromagnetic properties of circular dielectric waveguides

A variational method, based on the telegraphists equations, is used to calculate the dispersion and scattering characteristics of circular dielectric waveguides which arc enclosed by perfectly conducting walls of rectangular cross-section. Our propagation solutions are compared with those obtained by other authors and the convergence of the method is evaluated. A procedure which combines this variational method with the modal matching technique was implemented in order to analyse multiple discontinuities in cyclindrical dielectric waveguides. To verify the usefulness and accuracy of the procedure, theoretical and experimental results were obtained for different dielectric guiding structures, connected by means of abrupt and gradual transitions. The experimental values show a good agreement with the theoretical ones.

A MapReduce Implementation of the Spreading Activation Algorithm for Processing Large Knowledge Bases Based on Semantic Networks

The emerging Web of Data as part of the Semantic Web initiative and the sheer mass of information now available make it possible the deployment of new services and applications based on the reuse of existing vocabularies and datasets. A huge amount of this information is published by governments and organizations using semantic web languages and formats such as RDF, implicit graph structures developed using W3C standard languages: RDF-Schema or OWL, but new flexible programming models to process and exploit this data are required. In that sense the use of algorithms such as Spreading Activation is growing in order to find relevant and related information in this new data realm. Nevertheless the efficient exploration of the large knowledge bases has not yet been resolved and that is why new paradigms are emerging to boost the definitive deployment of the Web of Data. This cornerstone is being addressed applying new programming models such as MapReduce in combination with old-fashioned techniques of Document and Information Retrieval. In this paper an implementation of the Spreading Activation technique based on the MapReduce programming model and the problems of applying this paradigm to graph-based structures are introduced. Finally, a concrete experiment with real data is presented to illustrate the algorithm performance and scalability.

Towards a Stepwise Method for Unifying and Reconciling Corporate Names in Public Contracts Metadata: The CORFU Technique

The present paper introduces a technique to deal with coporate names heterogeneities in the context of public procurement metadata. Public bodies are currently facing a big challenge trying to improve both the performance and the transparency of administrative processes. The e-Government and Open Linked Data initiatives have emerged as efforts to tackle existing interoperability and integration issues among ICT-based systems but the creation of a real transparent environment requires much more than the simple publication of data and information in specific open formats; data and information quality is the next major step in the pubic sector. More specifically in the e-Procurement domain there is a vast amount of valuable metadata that is already available via the Internet protocols and formats and can be used for the creation of new added-value services. Nevertheless the simple extraction of statistics or creation of reports can imply extra tasks with regards to clean, prepare and reconcile data. On the other hand, transparency has become a major objective in public administractions and, in the case of public procurement, one of the most interesting services lies in tracking rewarded contracts (mainly type, location, and supplier). Although it seems a basic kind of reporting service the truth is that its generation can turn into a complex task due to a lack of standardization in supplier names or the use of different descriptors for the type of contract. In this paper, a stepwise method based on natural language processing and semantics to address the unfication of corporate names is defined and implemented. Moreover a research study to evaluate the precision and recall of the proposed technique, using as use case the public dataset of rewarded public contracts in Australia during the period 2004-2012, is also presented. Finally some discussion, conclusions and future work are also outlined.

An Extensible Framework to Sort out Nodes in Graph-Based Structures Powered by the Spreading Activation Technique: The ONTOSPREAD Approach

This paper presents an extensible framework for the Spreading Activation technique. This technique is supported by the ONTOSPREAD framework enabling the development, configuration, customization, and execution of the Spreading Activation method on graph-based structures. It has been used for a long time to the efficient exploration of knowledge bases built on semantic networks in Information and Document Retrieval domains. The emerging Web of Data and the sheer mass of information now available make it possible the deployment of new services and applications based on the reuse of existing vocabularies and datasets. A large amount of this information is published using semantic web languages and formats such as RDF, implicit graph structures developed using W3C standard languages; but new flexible and scalable methods to create added-value services and exploit the data are required. That is why ONTOSPREAD is considered relevant in providing a new way to implement the double process of activation and spreading of concepts in graph-based structures, more specifically to browse and rank resources in the Web of Data realm. The original constraints like weight degradation according to the distance are provided in combination with others coming from the extension of this technique like the converging paths reward. Finally an evaluation methodology and two examples using the well-known ontologies GALEN and SNOMED CT are presented to validate the goodness, the improvement, and the capabilities of this technique.

ONTOSPREAD: A Framework for Supporting the Activation of Concepts in Graph-Based Structures through the Spreading Activation Technique

The present paper introduces the ONTOSPREAD framework for the development, configuration, customization and execution of the Spreading Activation technique over graph-based structures, more specifically over RDF graphs and ontologies arising from the Semantic Web area. This technique has been used to the efficient exploration and querying of large and heterogeneous knowledge bases based on semantic networks in the Information and Document Retrieval domains. ONTOSPREAD implements the double process of activation and spreading of concepts in ontologies applying different restrictions of the original model like weight degradation according to the distance or others coming from the extension of this technique like the converging paths reward. This technique provide a whole framework to ease the information access, common required feature in the exploitation of the current Web of Data. Moreover, it is considered to be relevant to support the recommendation of concepts in different fields liked e-health, e-procurement or e-tourism with the objective of getting a set of ranked resources. Finally an evaluation methodology and two examples using ontologies from different domains are provided to validate the goodness, the improvement and the capabilities of this framework applied to digital libraries.

Equivalent-optical-waveguide model for the analysis of optical waveguides by means of an asymptotic effective-index method

We present a theoretical method that makes it possible to analyze three-dimensional (3-D) integrated optical waveguides with arbitrary refractive-index profiles. With this method it is easy to obtain effective indexes, propagation constants, and coupling-switching properties of planar and channel optical waveguides. This theoretical approach involves ones modeling the original optical waveguide by means of an equivalent optical waveguide whose effective index is evaluated by the application of a technique that we call the asymptotic effective-index method. The numerical values show good convergence and accuracy for effective indexes, propagation constants, and coupling-switching characteristics. Theoretical and experimental results are given.

Inductive representations of RDF graphs

RDF forms the basis of the semantic web technology stack. It is based on a directed graph model where nodes and edges are identified by URIs. Occasionally, such graphs contain literals or blank nodes. The existential nature of blank nodes complicates the graph representation.In this paper we propose a purely functional representation of RDF graphs using a special form of inductive graphs called inductive triple graphs. We employ logical variables to represent blank nodes. This approach can be implemented in any functional programming language such as Haskell and Scala. We propose a purely functional representation of RDF graphs.We present two implementations in Haskell and Scala.We outline an algebra of RDF graphs with common operations like mapping, folding, or merging.We demonstrate the potential advantages of an inductive representation of RDF graphs.We outline some possible applications such as parallel programming among others.

Inductive Triple Graphs: A Purely Functional Approach to Represent RDF

RDF is one of the cornerstones of the Semantic Web. It can be considered as a knowledge representation common language based on a graph model. In the functional programming community, inductive graphs have been proposed as a purely functional representation of graphs, which makes reasoning and concurrent programming simpler. In this paper, we propose a simplified representation of inductive graphs, called Inductive Triple Graphs, which can be used to represent RDF in a purely functional way. We show how to encode blank nodes using existential variables, and we describe two implementations of our approach in Haskell and Scala.