Tame and wild theorem for the category of filtered by standard modules for a quasi-hereditary algebra

We introduce the notion of interlaced weak ditalgebras and apply reduction procedures to their module categories to prove the tame-wild dichotomy for the category ${\cal F}(\Delta)$ of filtered by standard modules for a quasi-hereditary algebra. Moreover, in the tame case, we show that given a fixed dimension $d$, for every $d$-dimensional indecomposable module $M \in {\cal F}(\Delta)$, with the only possible exception of those lying in a finite number of isomorphism classes, the module $M$ coincides with its Auslander-Reiten translate in ${\cal F}(\Delta)$. Our results are based on a theorem by Koenig, K\"ulshammer, and Ovsienko relating ${\cal F}(\Delta)$ with the module category of some special type of ditalgebra.Comment: 51 page

Special Issue: new trends in Process Simulation and Modeling

This special issue of the Journal of Industrial Engineering and Management is focused on new trends in Process Simulation and Modeling.Many business processes are so complex, interconnected and subject to variability. For those reasons, it is hard to understand the components evolution and interactions within the business processes without a dynamic model. Simulation and modeling approach is a good choice to predict processes performance, to compare alternatives and to establish the effect of several scenarios on performance. Moreover, if a process does not yet exist, or company is considering a new implementation, a simulation model can give a clue how well the proposed process will perform. In addition, process simulation and modeling is a growing and exciting research field.Peer Reviewe

MODELO BIDIMENSIONAL DE RIESGOS DEL MANTENIMIENTO DE SISTEMAS INTEGRADOS DE GESTIÓN (ERP)

La adopción y expansión de las Tecnologías de la Información y la Comunicación en el ámbito empresarial se está produciendo a gran velocidad. De la mano de las más innovadoras TIC y de los sistemas informáticos, surgen y se desarrollan los sistemas ERP. Éstos han sido implantados por empresas de todo el mundo. Tras su implantación, comienza su mantenimiento. Para que el resultado de estos proyectos sea satisfactorio, los riesgos que lo afectan tienen que ser gestionados. Una pobre gestión de estos riesgos, con frecuencia origina fallos en el sistema, lo que hace que las compañías tengan que asumir altas pérdidas. Para gestionar adecuadamente los riesgos, los profesionales deben comenzar identificándolos y clasificándolos. Para apoyar su labor, hemos realizado un estudio formal de los riesgos que afectan al mantenimiento de ERPs. La investigación finaliza con la elaboración de un Modelo de dos dimensiones compuesto por los riesgos identificados en la literatura

Dorsal and ventral stimuli in cell–material interactions: effect on cell morphology

Cells behave differently between bidimensional (2D) and tridimensional (3D) environments. While most of the in vitro cultures are 2D, most of the in vivo extracellular matrices are 3D, which encourages the development of more relevant culture conditions, seeking to provide more physiological models for biomedicine (e.g., cancer, drug discovery and tissue engineering) and further insights into any dimension-dependent biological mechanism. In this study, cells were cultured between two protein coated surfaces (sandwich-like culture). Cells used both dorsal and ventral receptors to adhere and spread, undergoing morphological changes with respect to the 2D control. Combinations of fibronectin and bovine serum albumin on the dorsal and ventral sides led to different cell morphologies, which were quantified from bright field images by calculating the spreading area and circularity. Although the mechanism underlying these differences remains to be clarified, excitation of dorsal receptors by anchorage to extracellular proteins plays a key role on cell behavior. This approach—sandwich-like culture—becomes therefore a versatile method to study cell adhesion in well-defined conditions in a quasi 3D environment

Change in Elasmobranchs and Other Incidental Species in the Spanish Deepwater Black Hake Trawl Fishery off Mauritania (1992–2001)

From 1992 to 2001, by-catch that was landed from the Spanish deepwater trawl fishery for black hake off Mauritania was closely monitored. This is a highly specialised fishery, with two species of black hake (Merluccius senegalensis and Merluccius polli) constituting between 77–99% of total landings, which have annually averaged 9 300 tons over the past two decades. Landings of Sparidae were highest among by-catch species of commercial value, with the large-eye dentex, Dentex macrophthalmus being the most important until 1996, after which the family Lophiidae and others predominated. Next were the Elasmobranchii, including large demersal squalids and several species of rays, although their annual landings fell from 182 tons in 1992 to only 4 tons in 1999, rising to 37 tons in 2001. The present paper analyses these changes using by-catches retained in the black hake fishery. We believe that the decline could be due to a set of different factors: a change in depths fished, economic reasons and probable over-exploitation of both targeted species and by-catch. Elasmobranchs constituted only 0.1% of total landings in 1999, compared to 1.9% in 1992, although their contribution to total commercial by-catch was constant. Seasonality was clearly evident, with an absolute and proportional rise in elasmobranch by-catch during warm periods, reaching 75% of by-catch landings in some months, coinciding with a drop in total by-catch. These seasonal variations could be related to the migratory habits of the fishery's target species, black hake

Composition of Demersal Fish Assemblages in Deep-waters of the Western Guinean Gulf

Data from deep water hauls carried out during the Spanish Research trawling Survey 'GUINEA -90', conducted in Sierra Leone, Liberia, Ivory Coast and Ghana, between 100 and 700 m depth, were analysed. The taxonomic list of the survey showed a total of 91 fish species caught between 100 and 700 m depth. The maximum species richness and the highest abundances were found between 2000 and 300 m (60 species), depth range corresponding to the breaking of the continental shelf and to the upper part of the slope. Despite the local differences, the 'GUINEA -90' Survey showed the existence of fish assemblages

An AHP-based methodology to rank Critical Success Factors of Executive Information Systems

For academics and practitioners concerned with computer-based Information Systems, one central issue is the study of Critical Success Factors of Information Systems development and implementation. Whereas several Critical Success Factors analyses appear in the literature, most of them do not have any technical background. In this paper we propose the use of the Analytic Hierarchy Process to set Critical Success Factors priorities. Results suggest that technical elements are less critical than information and human factors and that an adequate knowledge of the information requirements of users is the most important Critical Success Factors related with Executive Information Systems.Department of Business Organization and MarketingPostprin

Parallelization of the PC Algorithm

This paper describes a parallel version of the PC algorithm for learning the structure of a Bayesian network from data. The PC algorithm is a constraint-based algorithm consisting of fi ve steps where the first step is to perform a set of (conditional) independence tests while the remaining four steps relate to identifying the structure of the Bayesian network using the results of the (conditional) independence tests. In this paper, we describe a new approach to parallelization of the (conditional) independence testing as experiments illustrate that this is by far the most time consuming step. The proposed parallel PC algorithm is evaluated on data sets generated at random from five different real- world Bayesian networks. The results demonstrate that signi cant time performance improvements are possible using the proposed algorithm