60 research outputs found
Temporal characterization of the requests to Wikipedia
This paper presents an empirical study about the temporal patterns
characterizing the requests submitted by users to Wikipedia.
The study is based on the analysis of the log lines registered by the
Wikimedia Foundation Squid servers after having sent the appropriate
content in response to users' requests. The
analysis has been conducted regarding the ten most visited editions of
Wikipedia and has involved more than 14,000 million log lines
corresponding to the traffic of the entire year 2009. The conducted methodology
has mainly consisted in the parsing and filtering
of users' requests according to the study directives. As a result, relevant information
fields have been finally stored in a database for persistence and further
characterization. In this way, we, first, assessed, whether the traffic to Wikipedia could serve
as a reliable estimator of the overall traffic to all the Wikimedia Foundation
projects. Our subsequent analysis of the temporal evolutions corresponding to
the different types of requests to Wikipedia revealed interesting differences
and similarities among them that can be related to the users' attention to the Encyclopedia.
In addition, we have performed separated characterizations of each Wikipedia edition
to compare their respective evolutions over time
A quantitative examination of the impact of featured articles in Wikipedia
This paper presents a quantitative examination of the impact of the presentation of featured articles as quality content in the main page of several Wikipedia editions. Moreover, the paper also presents the analysis performed to determine the number of visits received by the articles promoted to the featured status. We have analyzed the visits not only in the month when articles awarded the promotion or were included in the main page, but also in the previous and following ones. The main aim for this is to assess the attention attracted by the featured content and the different dynamics exhibited by each community of users in respect to the promotion process. The main results of this paper are twofold: it shows how to extract relevant information related to the use of Wikipedia, which is an emerging research topic, and it analyzes whether the featured articles mechanism achieve to attract more attention
Characterization of the Wikipedia Traffic
Since its inception, Wikipedia has grown to a solid and stable project and turned into a mass collaboration tool that allows the sharing and distribution of knowledge. The wiki approach that basis this initiative promotes the participation and collaboration of users. In addition to visits for browsing its contents, Wikipedia also receives the contributions of users to improve them. In the past, researchers paid attention to different aspects concerning authoring and quality of contents. However, little effort has been made to study the nature of the visits that Wikipedia receives. We conduct such an study using a sample of users' requests provided by the Wikimedia Foundation in the form of Squid log lines. Our sample contains more that 14,000 million requests from users all around the world and directed to all the projects maintained by the Wikimedia Foundation, including different editions of Wikipedia. This papers describes the work made to characterize the traffic directed to Wikipedia and consisting of the requests sent by its users. Our main aim is to obtain a detailed description of its composition in terms of the percentages corresponding to the different types of requests making part of it. The benefits from our work may range from the prediction of traffic peaks to the determination of the kind of resources most often requested, which can be useful for scalability considerations
Effect of the support composition on the vapor-phase hydrogenation of crotonaldehyde over Pt/CexZr1-xO2 catalysts
Vapor-phase hydrogenation of toluene and selective hydrogenation of crotonaldehyde (2-butenal) have been performed at 333 K over Cl-free Pt/ZrO2 and Pt/CexZr1−xO2 catalysts (0.2⩽x⩽0.8) after reduction under H2 at low (473 K) and high (773 K) temperatures. The catalysts were characterized by X-ray diffraction, Raman spectroscopy, temperature-programmed reduction, and X-ray photoelectron spectroscopy after each reduction treatment. An important effect of the support composition on the catalytic activity was observed for both reactions. The catalytic behavior of Pt in the two test reactions studied was strongly dependent on the support composition and on the reduction temperature. For toluene hydrogenation, after reduction at 473 K, catalytic activity was higher for catalysts with no or low ceria content. Furthermore, whereas the increase in the reduction temperature hardly modified the activity of Pt/ZrO2, it strongly deactivated the catalysts with high cerium content in the support. For crotonaldehyde hydrogenation, on the other hand, increased reduction temperature produced a general increase in activity (except for the catalyst with the highest cerium content), along with an increase in selectivity toward the hydrogenation of the carbonyl bond to yield crotyl alcohol. The results are explained on the basis of the effect of partial reduction of Ce(IV) in the support
Zn-modified MCM-41 as support for Pt catalysts
The effect of Zn location and reduction temperature have been studied on pure and Zn-modified MCM-41 supported Pt catalysts. Experimental results show that incorporation of Zn into the siliceous framework of the MCM-41 material introduces structural oxidized Zn centres with a high stability towards a reduction treatment even at high temperatures. XP spectra confirm the high stability of these Zn species although, at the highest reduction temperature (723 K), a high mobility of the doping cations from structural positions to the inner wall of the mesopores is observed. Catalytic studies in the chemoselective hydrogenation of crotonaldehyde show that the presence of Zn produces an important decrease in the catalytic activity of the Pt nanoparticles, in accordance with Pt dispersion measurements. However, the presence of Zn improves the selectivity towards the formation of crotyl alcohol. Compared with a conventional impregnated PtZn/MCM-41 catalyst, structural Zn centres in the doped Pt/ZnMCM-41 catalysts exhibit a higher polarizing/activation of the carbonyl double bond giving rise to a higher yield to crotyl alcohol, the product of interest. Additionally, these Zn-modified MCM-41-based Pt catalysts show an excellent behaviour in an important industrial reaction such as the dehydrogenation of iso-butane to iso-butene, with a selectivity of 100%, which remains stable with time on stream.Es la versión preprint del artículo. Se puede consultar la versión final en https://doi.org/10.1016/j.apcata.2008.08.02
Hydrogenation of α, β unsaturated aldehydes over polycrystalline, (111) and (100) preferentially oriented Pt nanoparticles supported on carbon
The influence of the shape/surface structure of Pt nanoparticles on the selective hydrogenation of crotonaldehyde and cinnamaldehyde has been studied. (111) and (100) preferentially oriented Pt nanoparticles (10 nm) as well as polyoriented Pt nanoparticles (3 nm) were synthesized, characterized (by TEM, cyclic voltammetry and adsorption microcalorimetry) and their catalytic properties evaluated. TEM analysis provided information about the size and shape of the Pt nanoparticles, whereas cyclic voltammetry allowed gaining qualitative and quantitative information about their surface structure. Thus, small Pt nanoparticles (
) were revealed to have a polyoriented surface, containing high ratio of corner and edges atoms to terrace atoms, whereas large Pt nanoparticles (
) were shown to have larger Pt domains with (100) and (111) surface structures. Microcalorimetric results for CO adsorption showed higher values of initial heat for polyoriented Pt/C compared to preferentially oriented samples, thus accounting for a higher amount of highly unsaturated surface platinum atoms for Pt/C, in agreement with cyclic voltammetry. The catalytic performances of the samples showed a strong structure-sensitive character for both reactions, with TOF values following the trend Pt(100)/C > Pt(111)/C > Pt/C. Moreover, Pt(111)/C showed higher selectivities to unsaturated alcohol than Pt(100)/C and Pt/C samples.Es la versión prepritn del artículo. Se puede consultar la versión final en https://doi.org/10.1016/j.jcat.2007.10.01
Culto y culturas en la cueva de Gorham (Gibraltar): La historia del santuario y sus materiales inscritos
This paper presents an updated overview of the ongoing archaeological research carried out in the Protohistoric sanctuary of Gorham’s Cave (Gibraltar). It is based on the results of recent excavations, focusing on incised pottery with inscriptions or other marks. The catalogue of inscriptions includes both Phoenician and Graeco-Iberian examples, which could be related with the deposition of votive offerings from Archaic to Hellenistic periods.El artículo presenta un nuevo estado de la cuestión arqueológico sobre el santuario protohistórico de la Cueva de Gorham (Gibraltar) a la luz de los resultados de las recientes campañas de excavación y estudia los materiales cerámicos con inscripciones u otro tipo de marcas hallados en la cueva. El catálogo incluye un nuevo grafito fenicio y una inscripción greco-ibérica que se relacionan con las ofrendas depositadas en el lugar desde época arcaica hasta el periodo helenístico
A cohort of patients with COVID-19 in a major teaching hospital in Europe
Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMArtículo escrito en nombre del COVID@HULP Working GroupSince the confirmation of the first patient infected with SARS-CoV-2 in Spain in January 2020, the epidemic has grown rapidly, with the greatest impact on the region of Madrid. This article describes the first 2226 adult patients with COVID-19, consecutively admitted to La Paz University Hospital in Madrid. Methods: Our cohort included all patients consecutively hospitalized who had a final outcome (death or discharge) in a 1286-bed hospital of Madrid (Spain) from 25 February (first case admitted) to 19 April 2020. The data were manually entered into an electronic case report form, which was monitored prior to the analysis. Results: We consecutively included 2226 adult patients admitted to the hospital who either died (460) or were discharged (1766). The patients’ median age was 61 years, and 51.8% were women. The most common comorbidity was arterial hypertension (41.3%), and the most common symptom on admission was fever (71.2%). The median time from disease onset to hospital admission was 6 days. The overall mortality was 20.7% and was higher in men (26.6% vs. 15.1%). Seventy-five patients with a final outcome were transferred to the intensive care unit (ICU) (3.4%). Most patients admitted to the ICU were men, and the median age was 64 years. Baseline laboratory values on admission were consistent with an impaired immune-inflammatory profile. Conclusions: We provide a description of the first large cohort of hospitalized patients with COVID-19 in Europe. Advanced age, male sex, the presence of comorbidities and abnormal laboratory values were more common among the patients with fatal outcome
Tumor targeted 4-1BB agonist antibody-albumin fusions with high affinity to FcRn induce anti-tumor immunity without toxicity
17 p.-4 fig.-1 tab.-1 grph. abst.Costimulation of tumor-infiltrating T lymphocytes by anti-4-1BB monoclonal antibodies (mAbs) has shown anti-tumor activity in human trials, but can be associated with significant off-tumor toxicities involving FcγR interactions. Here, we introduce albumin-fused mouse and human bispecific antibodies with clinically favorable pharmacokinetics designed to confine 4-1BB costimulation to the tumor microenvironment. These Fc-free 4-1BB agonists consist of an EGFR-specific VHH antibody, a 4-1BB-specific scFv, and a human albumin sequence engineered for high FcRn binding connected in tandem (LiTCo-Albu). We demonstrate in vitro cognate target engagement, EGFR-specific costimulatory activity, and FcRn-driven cellular recycling similar to non-fused FcRn high-binding albumin. The mouse LiTCo-Albu exhibited a prolonged circulatory half-life and in vivo tumor inhibition, with no indication of 4-1BB mAb-associated toxicity. Furthermore, we show a greater therapeutic effect when used in combination with PD-1-blocking mAbs. These findings demonstrate the feasibility of tumor-specific LiTCo-Albu antibodies for safe and effective costimulatory strategies in cancer immunotherapy.Financial support for this work was obtained from the MCIN/AEI/10.13039/501100011033 (SAF2017-89437-P and PDC2021-121711-100 to LA-V, PID2019-104544GB-I00 to CA, and PID2020-113225GB-I00 to FJB), partially supported by the European Regional Development Fund (ERDF); the Carlos III Health Institute (ISCIII) (PI19/00132 to LS; PI20/01030 to BB), partially supported by the ERDF; the ISCIII-RICORS within the Next Generation EU program (plan de Recuperación, Transformación y Resilencia); the Spanish Association Against Cancer (AECC 19084 to LA-V); the CRIS Cancer Foundation (FCRIS-2018-0042 and FCRIS-2021-0090 to LA-V), the BBVA Foundation (Ayudas Fundación BBVA a Equipos de Investigación Científica SARS-CoV-2 years COVID-19 to LA-V); and the Fundació “La Caixa” (HR21-00761 project IL7R_LungCan to LA-V). AD, OAM, and KAH were funded by the Novo Nordisk Foundation, Grant; CEMBID (Center for Multifunctional Biomolecular Drug Design, Grant Number: NNF17OC0028070). OH was supported by an industrial PhD fellowship from the Comunidad de Madrid (IND2020/BMD-17668). AE-L was supported industrial PhD fellowship from the Carlos III Health Institute (IFI18/00045). CD-A was supported by a predoctoral fellowship from the Spanish Ministry of Science Innovation and Universities (PRE2018-083445). LR-P was supported by a predoctoral fellowship from the Immunology Chair, Universidad Francisco de Vitoria/Merck. LD-A was supported by a Rio Hortega fellowship from the Carlos III Health Institute (CM20/00004).Peer reviewe
Análisis cuantitativo para la evaluación de competencias transversales en wikis
El proceso de Bolonia, materializado en el Espacio
Europeo de Educación Superior (EEES), ha supuesto la incorporación
de nuevas capacidades y destrezas a los itinerarios
educativos universitarios. Así, las directivas que emanan este
proceso promueven, además de una mayor involucración de los
estudiantes en su propio proceso formativo, el desarrollo de
competencias transversales relacionadas con el trabajo en equipo,
el análisis crítico, y la defensa y divulgación de ideas entre otras.
En este contexto, las herramientas Web 2.0 en general, y las
plataformas wiki en particular, se han revelado como eficaces
instrumentos para el desarrollo de actividades académicas basadas
en el enfoque colaborativo. En este trabajo, se presentan
dos experiencias basadas en el empleo de wikis, incluida la
propia Wikipedia, cada una con una herramienta de análisis con
el objetivo de discriminar patrones y perfiles de participación
por parte de los estudiantes. En concreto, nuestro estudio tiene
como objetivo presentar diversos indicadores cuantitativos que
pueden obtenerse de manera automática a partir de actividades
realizadas sobre wikis, así como discutir su utilidad para el
seguimiento y evaluación de las tareas.The Bologna Process, which has led to the foundation
of the European Higher Education Area, has brought
the inclusion of new capacities and skills in Higher education
curricula. The main directives given by this process promote,
in addition to a higher participation of students in their own
learning process, the development of generic competencies related
to teamwork, critical analysis and the dissemination and
discussion of ideas among others. In such a context, Web 2.0
tools, generally, and wiki platforms particularly, have proven to
be suitable mechanisms to support academic experiences based in
collaborative approaches, especially for the Bologna foundational
principles. In this paper, we presenttwo different initiatives
including the use of wiki platforms, including the Wikipedia,
each one using a different analytical tool with the aim of finding
different students’ profiles and patterns of participation. The
objective of this study is to show a number of quantitative
indicators that can be automatically obtained from activities
developed on wiki platforms and to discuss their utility in the
monitoring and assessment of tasks.info:eu-repo/semantics/publishedVersio
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