Group Size Effect on the Success of Wolves Hunting

Social foraging shows unexpected features such as the existence of a group size threshold to accomplish a successful hunt. Above this threshold, additional individuals do not increase the probability of capturing the prey. Recent direct observations of wolves in Yellowstone Park show that the group size threshold when hunting its most formidable prey, bison, is nearly three times greater than when hunting elk, a prey that is considerably less challenging to capture than bison. These observations provide empirical support to a computational particle model of group hunting which was previously shown to be effective in explaining why hunting success peaks at apparently small pack sizes when hunting elk. The model is based on considering two critical distances between wolves and prey: the minimal safe distance at which wolves stand from the prey, and the avoidance distance at which wolves move away from each other when they approach the prey. The minimal safe distance is longer when the prey is more dangerous to hunt. We show that the model explains effectively that the group size threshold is greater when the minimal safe distance is longer. Although both distances are longer when the prey is more dangerous, they contribute oppositely to the value of the group size threshold: the group size threshold is smaller when the avoidance distance is longer. This unexpected mechanism gives rise to a global increase of the group size threshold when considering bison with respect to elk, but other prey more dangerous than elk can lead to specific critical distances that can give rise to the same group size threshold. Our results show that the computational model can guide further research on group size effects, suggesting that more experimental observations should be obtained for other kind of prey as e.g. moose.Comment: 20 pages, 4 figures, 8 references. Other author's papers can be downloaded at http://www.denys-dutykh.com

Liver Transplantation for perihilar cholangiocarcinoma. Do we need to move forward?

Perihilar cholangiocarcinoma; Liver transplantation; OutcomesColangiocarcinoma perihilar; Trasplantament hepàtic; ResultatsColangiocarcinoma perihiliar; Trasplante hepático; ResultadosPerihilar cholangiocarcinoma (pCCA) is a challenging disease with limited options. Surgical resection and adjuvant therapy remain the only established treatment for those with resectable disease. Since the publication of the Mayo protocol in 2000, neoadjuvant chemoradiation and liver transplantation have become the standard of care in selected patients with unresectable de novo pCCA or resectable pCCA arising under primary sclerosing cholangitis. However, its application is diverse worldwide, and the need for donor organs is one of the main limitations. Also, differences in the neoadjuvant regimen used were observed. In this review, we discuss the latest results of this approach, the recommended tools for diagnostic work-up, and advances in systemic therapy to improve patient selection and long-term survival

Evolving temporal conceptual schemas: the reification case

We study temporal conceptual schema evolutions related to reification, a typical and complex modeling construct. Various types of reification are considered. Using a previously defined framework, we specify only at conceptual level (and without descending to logical or application levels), the effects of any possible evolution related to reification, thus reducing the complexity of the management of those changes.Peer ReviewedPostprint (published version

Genome-wide analysis of the emigrant family of MITEs: amplification dynamics and evolution of genes in Arabidopsis thaliana

MITEs are structurally similar to defective class II elements but their high copy number and the size and sequence conservation of most MITE families suggest that they can be amplified by a replicative mechanism. Here we present a genome-wide analysis of the Emigrant family of MITEs from Arabidopsis thaliana. In order to be able to detect divergent ancient copies and low copy number subfamilies with a different internal sequence we have developed a computer program (http://www.lsi.upc.es/~alggen) that allows looking for Emigrant elements based solely on its TIR sequence. Our results show that different bursts of amplification of one or very few active, or master, elements have occurred at different times during Arabidopsis evolution, with an insertion dynamics similar to that of some SINEs. The analysis of the insertion sites of the Emigrant elements show that, although Emigrant elements tend to integrate far from ORFs, the elements inserted within or close to genes are preferentially maintained during evolution.Postprint (published version

New learning scenarios for the 21st century related to Education, Culture and Technology

This paper presents a summary of proposals and new learning scenarios for the 21st century related to the theme of “Education, Culture and Technology”. These proposals and scenarios are based on the work conducted in 2014 by a group of experts from Andorra, Catalonia, the United States and the United Kingdom during the International Forum on Education and Technology (FIET) held in Tarragona, Spain. The main aim of this work is to analyze the interconnection between education and culture through the discussion and selection of best practices and to identify the role played by technology in this process. The methodology used in this qualitative research was the focus group, whereby a group of experts analyzed and selected a range of good practices related to the main issue. The results of this process were shared at two plenary sessions with 100 expert reviewers and 500 educators. After considering the challenges faced by education in the 21st century and the best practices selected by the experts, it was agreed that digital technology can promote the dialogue that is needed to create a culture of innovation and enhance new ways of learning, participating, and contributing to local and global culture. At the end of this paper we make several proposals and recommendations for constructing learning environments that integrate education, culture and technology for a transformative experience

Full machine translation for factoid question answering

In this paper we present an SMT-based approach to Question Answering (QA). QA is the task of extracting exact answers in response to natural language questions. In our approach, the answer is a translation of the question obtained with an SMT system. We use the n-best translations of a given question to find similar sentences in the document collection that contain the real answer. Although it is not the first time that SMT inspires a QA system, it is the first approach that uses a full Machine Translation system for generating answers. Our approach is validated with the datasets of the TREC QA evaluation.Peer ReviewedPreprin

The Creation of an Experimental Camp of Protohistory at the Iberian Settlement of Estinclells (Verdú, Urgell, Catalonia)

The site of Estinclells is an Iberian Culture settlement in the Municipality of Verdú, Urgell (Catalonia) dating from thethird century BC (See Figures 1 and 2). Archaeological work was carried out between 2002 and 2014 under the auspices of the Regional Museum of Urgell (Museu Comarcal de l’Urgell) and the Archaeology Section of the Centre d’Estudis Lacetans in the framework of the research project entitled, "Economy and Evolution of the Iberian population in the Corb, Ondara and Sió River Valleys: Excavation of the Iberian Settlement of Estinclells, Verdú

All optical implementation of a stochastic logic gate using a VCSEL with external optical injection

We perform numerical simulations of the dynamics of two VCSELs optically coupled in a master-slave configuration. We show that the interplay of nonlinearity and spontaneous emission noise can yield logic behavior, and the emergent outcome of such system is a reliable logic gate. Specifically in our case represents an all-optical logic gate, with the logic input encoded in the strength of the light injected in the slave laser by the master laser, and the fast and robust response decoded from the polarization state of the light emitted by the slave laser.Peer ReviewedPostprint (author’s final draft

Hydrogenation of furfural over supported Pd catalysts

Lignocellulosic biomass is the most abundant and economical non-fossil carbon source. Furthermore, it is not competitive with the food chain, coming from lignocellulosic wastes including agricultural and food processing, local urban solid and forestry wastes. However, these are made up of complex carbohydrates (mainly, cellulose and hemicellulose), which require to be broken down in their respective monomers. The hemicellulose is mainly composed of pentosans, which, after an initial hydrolysis step, are dehydrated to furfural. Furfural is an important platform molecule, since it has a wide range of applications, being considered the main chemical, aside from bioethanol, obtained from the sugar platform for the synthesis of chemicals, for plastics, agrochemical and pharmaceutical industries. In the present work, the hydrogenation of furfural in gas phase has been studied by using Pd as active phase, and different metal oxides as support, in order to elucidate the influence of the support on the catalytic performance. Furfural can be converted into chemicals with important applications in many different industrial fields. Thus, reduction of furfural can proceed through different pathways depending on the experimental conditions, where the nature of the catalysts plays a key role. In the case of Pd-based catalysts, the main products come from the decarbonylation of furfural.The catalytic results reveals that the nature of the support exerts an important influence on furfural conversion and yield. The highest conversion (92% after 5 h of TOS at 463 K) was attained with a Pd-SiO2 catalyst, with a furan yield of 70 mol%. This catalyst is the most selective to furan and a moderate deactivation is only observed after 5 h reaction. The catalytic performance demonstrates that decarbonylation reaction was the main pathway, although the formation of furfuryl alcohol and 2-methylfuran also suggests that the hydrogenation of the carbonyl group of furfural takes place.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

γ-Al2O3 as acid catalyst for dehydration of glucose to 5-hydroxymethylfurfural

Currently, the search and development of sustainable feedstocks for chemicals derived from petrol have gained worldwide attraction because of the instability of the price of crude oil, the reduction of fossil oil reserves, and the environmental concerns associated to the greenhouse effect caused by CO2 emissions, being biomass one of the world’s most important renewable carbon sources. The major component of plant-derived biomass are carbohydrates, being of great importance to develop efficient and green approaches to their valorization by conversion into high value-added products. Thus, glucose can be transformed by dehydration into 5-hydroxymethylfurfural (HMF), which is a versatile and key intermediate for the production of a wide variety of biobased chemicals and it is attracting much attention in biofuels and chemical industry. Different catalytic systems have been evaluated for HMF production from C6 carbohydrates as glucose, mostly based on heterogeneous catalysis as alternative to the use of liquid mineral acids. On the other hand, the high surface area, large pore size and thermal and hydrothermal stabilities of some mesoporous solids make them suitable for many catalytic processes. In the present work, the dehydration of glucose to HMF has been evaluated by using different mesoporous γ-Al2O3 with acid, neutral or basic character, in a biphasic water–MIBK solvent system to avoid the HMF degradation and its possible reaction with the intermediates from glucose to give soluble polymers and humins or acetalization with glucose. Different experimental parameters, such as reaction temperature and time, as well as the addition of inorganic salts have been studied in order to reach the maximum HMF yield.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Ministry of Economy and Competitiveness (CTQ2012-38204-C04-02 project), Junta de Andalucía (RNM-1565) and FEDER fund