Unsupervised Machine Learning for the Classification of Astrophysical X-ray Sources

The automatic classification of X-ray detections is a necessary step in extracting astrophysical information from compiled catalogs of astrophysical sources. Classification is useful for the study of individual objects, statistics for population studies, as well as for anomaly detection, i.e., the identification of new unexplored phenomena, including transients and spectrally extreme sources. Despite the importance of this task, classification remains challenging in X-ray astronomy due to the lack of optical counterparts and representative training sets. We develop an alternative methodology that employs an unsupervised machine learning approach to provide probabilistic classes to Chandra Source Catalog sources with a limited number of labeled sources, and without ancillary information from optical and infrared catalogs. We provide a catalog of probabilistic classes for 8,756 sources, comprising a total of 14,507 detections, and demonstrate the success of the method at identifying emission from young stellar objects, as well as distinguishing between small-scale and large-scale compact accretors with a significant level of confidence. We investigate the consistency between the distribution of features among classified objects and well-established astrophysical hypotheses such as the unified AGN model. This provides interpretability to the probabilistic classifier. Code and tables are available publicly through GitHub. We provide a web playground for readers to explore our final classification at https://umlcaxs-playground.streamlit.app.Comment: 21 pages, 11 figures. Accepted in MNRA

On the use of biased-randomized algorithms for solving non-smooth optimization problems

Soft constraints are quite common in real-life applications. For example, in freight transportation, the fleet size can be enlarged by outsourcing part of the distribution service and some deliveries to customers can be postponed as well; in inventory management, it is possible to consider stock-outs generated by unexpected demands; and in manufacturing processes and project management, it is frequent that some deadlines cannot be met due to delays in critical steps of the supply chain. However, capacity-, size-, and time-related limitations are included in many optimization problems as hard constraints, while it would be usually more realistic to consider them as soft ones, i.e., they can be violated to some extent by incurring a penalty cost. Most of the times, this penalty cost will be nonlinear and even noncontinuous, which might transform the objective function into a non-smooth one. Despite its many practical applications, non-smooth optimization problems are quite challenging, especially when the underlying optimization problem is NP-hard in nature. In this paper, we propose the use of biased-randomized algorithms as an effective methodology to cope with NP-hard and non-smooth optimization problems in many practical applications. Biased-randomized algorithms extend constructive heuristics by introducing a nonuniform randomization pattern into them. Hence, they can be used to explore promising areas of the solution space without the limitations of gradient-based approaches, which assume the existence of smooth objective functions. Moreover, biased-randomized algorithms can be easily parallelized, thus employing short computing times while exploring a large number of promising regions. This paper discusses these concepts in detail, reviews existing work in different application areas, and highlights current trends and open research lines

Integrating data warehouses with web data : a survey

This paper surveys the most relevant research on combining Data Warehouse (DW) and Web data. It studies the XML technologies that are currently being used to integrate, store, query, and retrieve Web data and their application to DWs. The paper reviews different DW distributed architectures and the use of XML languages as an integration tool in these systems. It also introduces the problem of dealing with semistructured data in a DW. It studies Web data repositories, the design of multidimensional databases for XML data sources, and the XML extensions of OnLine Analytical Processing techniques. The paper addresses the application of information retrieval technology in a DW to exploit text-rich document collections. The authors hope that the paper will help to discover the main limitations and opportunities that offer the combination of the DW and the Web fields, as well as to identify open research line

A multi-start biased-randomized algorithm for the capacitated dispersion problem

The capacitated dispersion problem is a variant of the maximum diversity problem in which a set of elements in a network must be determined. These elements might represent, for instance, facilities in a logistics network or transmission devices in a telecommunication network. Usually, it is considered that each element is limited in its servicing capacity. Hence, given a set of possible locations, the capacitated dispersion problem consists of selecting a subset that maximizes the minimum distance between any pair of elements while reaching an aggregated servicing capacity. Since this servicing capacity is a highly usual constraint in real-world problems, the capacitated dispersion problem is often a more realistic approach than is the traditional maximum diversity problem. Given that the capacitated dispersion problem is an NP-hard problem, whenever large-sized instances are considered, we need to use heuristic-based algorithms to obtain high-quality solutions in reasonable computational times. Accordingly, this work proposes a multi-start biased-randomized algorithm to efficiently solve the capacitated dispersion problem. A series of computational experiments is conducted employing small-, medium-, and large-sized instances. Our results are compared with the best-known solutions reported in the literature, some of which have been proven to be optimal. Our proposed approach is proven to be highly competitive, as it achieves either optimal or near-optimal solutions and outperforms the non-optimal best-known solutions in many cases. Finally, a sensitive analysis considering different levels of the minimum aggregate capacity is performed as well to complete our study.Peer ReviewedPostprint (published version

Biocracia y tanatocracia en los escenarios territoriales ante la reconfiguración del orden mundial

Nos encontramos en un punto crucial en la historia humana en el cual los sucesos de guerras, hambrunas, enfermedades, pestes, discriminación racial y cultural, aunado a los cambios climáticos, aumentos de temperatura, sequías e inundaciones han provocado pérdidas humanas, destrucción y deterioro de recursos naturales en una Tanatocracia cimentada en muerte donde lo principal es el control territorial y el poder sobre los recursos naturales. En contraste, la Biocracia se fundamenta en un poder político que permite el cuidado y respeto a la vida, a los derechos, no solo a humanos o hacia las diferentes culturas y territorios sino a los ecosistemas, a la naturaleza, a conservar la seguridad alimentaria y los recursos ecosistémicos como el suelo y el agua necesarios para preservar cualquier forma de vida existente. Las nuevas estructuras hegemónicas con apoyo de multilaterales visualizan al agua dulce como un bien económico factible de privatizarse; en otra perspectiva es un bien común al que en primer lugar tiene derecho el ecosistema que lo produce. Los países que destacan por su participación en un gasto militar, armamentista son Estados Unidos, Rusia, Alemania, China, Reino Unido e India. Por otro lado, Ecuador y Bolivia han formulado acciones en pro de la Biocracia, la sustentabilidad de su territorio a través de la conservación de la naturaleza. Por lo anterior, el objetivo del presente trabajo es evaluar en contraste a la Biocracia y la Tanatocracia como principios del desarrollo territorial ante la reconfiguración del orden mundial

Revisiting the Epipalaeolithic-Neolithic Transition in the Extreme NW of Africa : The Latest Results of the Chronological Sequence of the Cave of Kaf Taht el-Ghar (Tétouan, Morocco)

This study focuses on the chronostratigraphic sequence of the Cave of Kaf Taht el-Ghar (Dar Ben Karrich, Tétouan, Morocco) excavated in 2012 in the framework of the AGRIWESTMED research project. The broad sequence reveals a series of occupations ranging from the Pleistocene (Moroccan Aterian) to recent historical times. Our research identifies a rich Early Neolithic phase (sixth millennium cal BC) containing the earliest pottery and domesticated animal and plant remains in the western Maghreb. However, this Early Neolithic level is not an immediate successor of the last traces of the Epipalaeolithic hunter-gatherer occupation, which started at the end of the Younger Dryas (10,900-9700 cal BC). An abandonment phase, spanning more than a millennium, separated them. This hiatus appears to originate from a cold climatic event that began in the late seventh millennium cal BC (ca. 6200 BC) and ended around the mid-sixth millennium cal BC. La présente étude est centrée sur la séquence chronostratigraphique de la grotte de Kaf Taht el-Ghar (Dar Ben Karrich, Tétouan, Maroc), fouillée pour la dernière fois en 2012 dans le cadre du projet de recherche AGRIWESTMED. La séquence générale révèle une série d'occupations allant du Pléistocène (Atérien marocain) jusqu'aux temps historiques récents. Parmi les résultats les plus remarquables, on peut souligner l'identification d'une riche phase du Néolithique Ancien (6ème millénaire avant JC) contenant les plus anciens restes de poteries et de plantes et animaux domestiques datés au Maghreb occidental. Cette phase n'est. pas consécutive à l'occupation épipaléolithique, car il existe une nette rupture entre les deux phases, qui s'étend sur plus d'un millénaire. Cela semble coïncider en partie avec l'événement climatique froid de 6200 cal av. J.-C. Le début de l´ occupation épipaléolithique commencerait à son tour avec la fin du Dryas récent (10,900-9,700 cal av. J.-C.)

Maternal imprinting on cognition markers of wild type and transgenic Alzheimer's disease model mice.

The risk of suffering from Alzheimer's disease (AD) is higher in individuals from AD-affected mothers. The purpose of this investigation was to study whether maternal transmission might produce AD-related alterations in progenies of mice that do not have any genotypic alteration. We used cognitively-intact mothers harbouring in heterozygosity the transgene for overexpressing the Swedish double mutant version of the human amyloid precursor protein (hAβPPswe). The phenotype of the offspring with or without the transgene resulting from crossing young Tg2576 females with wild-type males were compared with those of the offspring resulting from crossing wild-type females with Tg2576 males. The hAβPPswe-bearing offspring from Tg2576 mothers showed an aggravated AD-like phenotype. Remarkably, cognitive, immunohistochemical and some biochemical features displayed by Tg2576 heterozygous mice were also found in wild-type animals generated from Tg2576 females. This suggests the existence of a maternal imprinting in the wild-type offspring that confers a greater facility to launch an AD-like neurodegenerative cascade. Such progeny, lacking any mutant amyloid precursor protein, constitutes a novel model to study maternal transmission of AD and, even more important, to discover early risk markers that predispose to the development of AD

Reflections on the Other Side. A Southern Iberia Origin for the First Pottery Production of Northern Morocco?

Archaeological works in Morocco (the Spanish-Moroccan team) were funded by a European Research Council Advanced Grant AGRIWESTMED (Origins and spread of agriculture in the western Mediterranean region) coordinated by L.P.-CH. Processing works were performed thanks to a IJCI-2016-27812 -Spanish Ministry of Science, Innovation and Universities-Universidad de Granada, Juan de la Cierva-Incorporacion Agreement (2016, by RMMS), and by funding provided in the framework of project "Archaeobiology of the Neolithic of the Southern Iberian Peninsula" (NeArqBioSI) A-HUM-460-UGR18 by Consejeria de Economia, Conocimiento, Empresas y Universidad. FEDER Programme - Andalusian CouncilGranada University. Finally, G. Perez-Jorda has carried out this research within the grant CIDEGENT/2019/00, funded by the Generalitat Valenciana.This work is a starting point for rethinking the role of the Iberian Peninsula in the neolithisation of northern Morocco. It focuses on the similarities and divergences between the first pottery productions and their decorations in both territories. This relationship is supported by the existence of an accurate chronological gradation between the first evidence of Neolithisation in Iberian Peninsula and that of northern Morocco which suggests a north–south direction. We also present arguments on the possible links between the early ceramics from the north of Morocco and those from the south of Iberia, providing a first approach to an issue that will need to be carefully analysed in future research.European Research Council Advanced Grant AGRIWESTMED (Origins and spread of agriculture in the western Mediterranean region)Consejeria de Economia, Conocimiento, Empresas y Universidad A-HUM-460-UGR18FEDER Programme - Andalusian CouncilGranada UniversityGeneralitat Valenciana European Commission General Electric CIDEGENT/2019/0

Improved control on the microwave devulcanizing of ground tire rubber by means of sulphur gas sensors

The success of a Ground Tire Rubber (GTR) devulcanization process relies on the elimination of the Sulphur atoms that are crosslinking the rubber polymer. From the Chemical point of view, this requires providing enough energy to break the Sulphur bonds while preserving the Carbon bonds, to ensure a high quality devulcanized GTR for being of interest to the rubber manufacturing industry. GTR is very responsive to microwaves due to the presence of Carbon Black (CB) in its composition, so the radiant energy is absorbed quickly in the form of thermal energy. When its temperature reaches 140°C, the breakage of Sulphur bonds may happen under an exothermic reaction, but also some new links might be built under that condition. Therefore, from the Physical point of view, the released Sulphur in the gaseous form of SO2, H2S, and/or CS2 must be promoted to abandon the reactor to avoid its recombination. In this work, microwave devulcanization is monitored by detecting the concentration of Sulphurous gases at the exhaust of the reactor. These sensors are very effective especially when pyrometer readings are degraded because of the gaseous layer on the GTR during the process.This research project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement number 870000. More information at https://valuerubber.eu/. The authors acknowledge CETEC and Synthelast for the GTR powder. Authors would like to extend the gratitude to Mr. Juan Antonio Albaladejo-López for his help with the mechanical development of the set u