Unbounded B-Fredholm operators on Hilbert spaces

This paper is concerned with the study of a class of closed linear operators densely defined on a Hilbert space H and called B-Fredholm operators. We characterize a B-Fredholm operator as the direct sum of a Fredholm closed operator and a bounded nilpotent operator. The notion of an index of a B-Fredholm operator is introduced and a characterization of B-Fredholm operators with index 0 is given in terms of the sum of a Drazin closed operator and a finite-rank operator. We analyse the properties of the powers Tm of a closed B-Fredholm operator and we establish a spectral mapping theorem

El valor añadido que aportan las redes sociales a las bibliotecas y a sus stakeholders

Sección: En directoTras este título podríamos preguntarnos si realmente las redes sociales han aportado valor añadido a las bibliotecas y a sus usuarios. Si estamos planteando, contribuyendo con estudios y resultados sobre el valor en general que las bibliotecas de todo tipo proporcionan a la sociedad (Gómez Yáñez, 2014), no es de extrañar que nos preguntemos si realmente los medios sociales están añadiendo algún valor a las bibliotecas y sus stakeholders.N

On the convergence of semiiterative methods to the Drazin inverse solution of linear equations in Banach spaces

We consider general semiiterative methods (SIMs) to find approximate solutions of singular linear equations of the type x = Tx + c, where T is a bounded linear operator on a complex Banach space X such that its resolvent has a pole of order ν1 at the point 1. Necessary and sufficient conditions for the convergence of SIMs to a solution of x = Tx+ c, where c belongs to the subspace range R(I − T) ν1 ν1, are established. If c ∈ R(I − T) sufficient conditions for the convergence to the Drazin inverse solution are described. For the class of normal operators in a Hilbert space, we analyze the convergence to the minimal norm solution and to the least squares minimal norm solution. 1

Separating Topological Noise from Features Using Persistent Entropy

Topology is the branch of mathematics that studies shapes and maps among them. From the algebraic definition of topology a new set of algorithms have been derived. These algorithms are identified with “computational topology” or often pointed out as Topological Data Analysis (TDA) and are used for investigating high-dimensional data in a quantitative manner. Persistent homology appears as a fundamental tool in Topological Data Analysis. It studies the evolution of k−dimensional holes along a sequence of simplicial complexes (i.e. a filtration). The set of intervals representing birth and death times of k−dimensional holes along such sequence is called the persistence barcode. k−dimensional holes with short lifetimes are informally considered to be topological noise, and those with a long lifetime are considered to be topological feature associated to the given data (i.e. the filtration). In this paper, we derive a simple method for separating topological noise from topological features using a novel measure for comparing persistence barcodes called persistent entropy.Ministerio de Economía y Competitividad MTM2015-67072-

Bibliometrics services and academic libraries: Towards transparency

Las unidades de bibliometría se están consolidando en el panorama universitario español debido al creciente interés de sus gestores universitarios por el rendimiento académico, ocupando los bibliotecarios un papel central en estas unidades como expertos en el apoyo y formación a los investigadores y el asesoramiento en la evaluación de la investigación. Se describen las funciones de estas unidades de bibliometría y se presenta una visión del panorama actual de las unidades de bibliometría en Españ

Las bibliotecas universitarias en su contexto actual

The academic libraries are complex institutions with a lot of roles; they have offered their services and products along the History and their main goal has been permanent: to offer access to the useful and real scientific information. But today, we are seeing that this role is not the same because of the digital technology. In this paper we try to show basics lines in order the academic libraries recover their prominent status in the digital era: selecting resources and management licences, working with metadata, offering reference virtual services, information literacy, digitizing documents, IR and learning spaces. These services come from the main mission of the academic library and they are in the line of the academic library future

A marketing plan is not a communication plan

Se aborda la diferencia entre un plan de comunicación y uno de marketing. Aunque tienen elementos que las asemejan, básicamente un plan de comunicación debe estar integrado en el de marketing. Sin Comunicación no hay Marketing porque la Comunicación es una de las etapas del marketing y sin Marketing tampoco hay Comunicación. La Comunicación es una de las principales tareas del Marketing, es un instrumento que se enmarca en la estrategia de marketing de la empresa o biblioteca. El marketing es el puente entre lo que las bibliotecas ofrecen y lo que los usuarios esperan y hay que estar dispuestos a comunicar de forma constante lo que los bibliotecarios son capaces de hacer para responder a las necesidades de sus usuarios. Un plan de marketing es un documento en el que se definen los objetivos y campos de responsabilidad de la función de marketing y posibilita el control de la gestión. Debe incluir una serie de apartados entre los que destaca la definición del objetivo, la escucha activa, la definición de los canales que se van a utilizar, el público objetivo al que se dirige la acción y el plan de acción. La evaluación continua del plan en clave para el éxito del proyecto. Se presentan una serie de ejemplos tanto de plan de comunicación como de marketing.We show the difference between the communication plan and the marketing plan. Despite the fact that both of them have a lot of similar characteristics, the communication plan has to be part of the marketing plan. Without communication it is not possible a marketing plan because the communication is one of the marketing plan parts. The communication is not possible without marketing. Communication is one of the most important tasks of marketing. It is a tool which is enshrined in the business or library strategy. Marketing is the bridge between what the libraries are offering and the users are expecting. We have to be ready to communicate steadily what the librarians are able to do in order to satisfy the user’s need. A marketing plan is a document where the objectives, communication channels, public objective and action plan are defined. The continuous assessment is the key to the success. We offer some examples of communication plan and marketing plan

What does user focus mean? Marketing strategy and tactics

Se expone la evolución del concepto de marketing para llegar a sus expresiones actuales como marketing de atracción, de contenidos y relacional, así como su especial implicación en el mundo de las bibliotecas y servicios de información. Se analiza la diferencia entre estrategia y táctica en marketing digital y se plantean las tendencias que los expertos ven más seguras a corto plazo, así como los retos que estas tendencias obligan a afrontar a las bibliotecas y organizaciones en general.The development of a marketing concept is described, and current types are explained: inbound marketing, content marketing and relationship marketing, especially concerning libraries and information services. Marketing strategy and tactics are analyzed. Finally, current marketing trends that experts predict for the short term, and the new challenges related to these trends that libraries, and organizations in general, have to confront are discussed