A collaborative filtering similarity measure based on singularities     

Jesús Bobadilla  Fernando OrtegaAntonio Hernando 《Information processing & management》2012

Recommender systems play an important role in reducing the negative impact of information overload on those websites where users have the possibility of voting for their preferences on items. The most normal technique for dealing with the recommendation mechanism is to use collaborative filtering, in which it is essential to discover the most similar users to whom you desire to make recommendations. The hypothesis of this paper is that the results obtained by applying traditional similarities measures can be improved by taking contextual information, drawn from the entire body of users, and using it to calculate the singularity which exists, for each item, in the votes cast by each pair of users that you wish to compare. As such, the greater the measure of singularity result between the votes cast by two given users, the greater the impact this will have on the similarity. The results, tested on the Movielens, Netflix and FilmAffinity databases, corroborate the excellent behaviour of the singularity measure proposed.  相似文献   

Raman mapping analysis of pigments from Proas Iluminadas by Quinquela Martín     

Emilia B. Halac  María Reinoso  Marcelo Luda  Fernando Marte 《Journal of Cultural Heritage》2012,13(4):469-473

The painting Proas Iluminadas (Illuminated Bows) by Benito Quinquela Martín is studied by Raman spectroscopy in order to analyse the technique and the pigments employed by the artist: ultramarine blue, carbon black, cadmium-sulphure based compounds for the hue of yellow, orange and red; also zinc white, barium yellow, massicot yellow and viridian were observed. The importance of using different excitation laser lines in the analysis of mixtures of pigments is highlighted. The Raman mapping analysis of cross section samples shows the way the artist composed the ground layer: a lead white stratum over a calcite one. It also allows distinguishing between a mixture of components and strata superposition, both presenting the same appearance under an optical microscope. This paper provides information about the materials and techniques used in a period of Argentine art not studied before from this point of view.  相似文献   

Agents control in intelligent learning systems: The case of reactive characteristics     

Ana Lilia Laureano-Cruces  Javier Ramírez-Rodríguez  Fernando de Arriaga  Rafael Escarela-Pérez 《Interactive Learning Environments》2013,21(2):95-118

Intelligent learning systems (ILSs) have evolved in the last few years basically because of influences received from multi-agent architectures (MAs). Conflict resolution among agents has been a very important problem for multi-agent systems, with specific features in the case of ILSs. The literature shows that ILSs with cognitive or pedagogical agents are prone to arbitration methods, where as ILSs with reactive agents are much in favor of control mechanisms. For these kind of systems, different control types are proposed based on the different stimuli that these agents will receive. These stimuli are aspects to be evaluated during the teaching/learning process such as: (1) error analysis, (2) learning styles, (3) analogies, (4) social aspects, etc.

The paper reviews several ILSs, related to our work; different control mechanisms are proposed to solve the agents' intervention conflicts. Finally, the use of several mechanisms is exemplified by the results of a specific ILS.  相似文献   

The relationship between teacher’s autonomy support and students’ autonomy and vitality     

Juan L. Núñez  Celia Fernández  Fernando Grijalvo 《Teachers and Teaching》2013,19(2):191-202

Abstract

Within education, some teachers’ interpretation of professionalism emphasizes conformity to the perceived norms of collective associations. Unprofessional behaviour, often equated with ‘unethical’ behaviour, is seen by many to be that which threatens solidarity and loyalty to colleagues. Informal norms typified by casual collegial relations as well as more formal attachments to organized unions or teachers’ federations exert a significant influence on individuals’ behaviour within the group. Professional ethics, in this sense, become concerned primarily with how one relates to colleagues rather than how one fulfils moral responsibilities to students. Qualitative findings from interviews with elementary and secondary school teachers suggest that, as a result of an ethic of collegial loyalty, some teachers experience personal moral and ethical dilemmas that they find difficult to resolve. Some respondents acknowledged that this can enable serious situations to be ignored or ‘covered up’. This paper examines some of the tensions and dilemmas experienced by teachers and raises questions about the ethical adequacy of defining professionalism in terms of inter‐colleague behaviour.  相似文献   

Determinants of cultural and popular celebration attendance: the case study of Seville Spring Fiestas     

María Luisa Palma  Luis Palma  Luis Fernando Aguado 《Journal of Cultural Economics》2013,37(1):87-107

The Spring Fiestas in Seville (Spain) (SFS) are the most important cultural events in the city each year. The present paper pursues two aims. The first is to characterize the SFS as a new prototype of a complex cultural good that expresses the link between the people and the place in which they live based on material and immaterial cultural heritage represented through popular celebrations. The second goal is to conduct an empirical analysis of the determinants that shape attendance intensity by estimating a zero-truncated count data model using a unique dataset of attendees at the SFS in 2009. Findings indicate that attendance is strongly associated with variables reflecting knowledge, institutional links, past experiences, and the perceived external benefits generated by the existence of the SFS. The article contributes to the literature by exploring participation in popular celebrations, a field of inquiry that to date is extremely limited in cultural economics.  相似文献   

Granite desalination using electromigration. Influence of type of granite and saline contaminant     

Jorge Feijoo  Xosé Ramón Nóvoa  Teresa Rivas  María Jesús Mosquera  Javier Taboada  Cristina Montojo  Fernando Carrera 《Journal of Cultural Heritage》2013,14(5):365-376

We describe the results of electromigration desalination of two soluble salt-contaminated Galician granites. The efficacy of electromigration, which had not been previously applied to granite, was assessed for two types of granite contaminated with a 20% NaCl solution and seawater. Desalination effectiveness was evaluated as follows: (1) analysis of anode and cathode ion content during testing; (2) analysis of ions at different distances from the electrodes after testing; (3) pH assessment of the stone surfaces; and (4) evaluation of colour changes. Results were very satisfactory; by the end of testing, chloride was reduced by almost 100% in both the NaCl and seawater contaminated samples. Sulfate reduction was also significant, despite this ion's lower mobility. The granite pH values remained close to neutral and colour changes were minimal. The difference in effectiveness of the process for the two types of stone was associated with their dissimilar pore structure.  相似文献   

Effects of purposeful soccer heading on circulating small extracellular vesicle concentration and cargo     

Eric R. Muoz  Jaclyn B. Caccese  Brittany E. Wilson  Kyle T. Shuler  Fernando V. Santos  Carolina T. Cabn  John J. Jeka  Dianne Langford  Matthew B. Hudson 《运动与健康科学(英文)》2021,10(2):122

BackgroundConsidering the potential cumulative effects of repetitive head impact (HI) exposure, we need sensitive biomarkers to track short- and long-term effects. Circulating small extracellular vesicles (sEVs) (<200 nm) traffic biological molecules throughout the body and may have diagnostic value as biomarkers for disease. The purpose of this study was to identify the microRNA (miRNA) profile in circulating sEVs derived from human plasma following repetitive HI exposure.MethodsHealthy adult (aged 18–35 years) soccer players were randomly assigned to one of 3 groups: the HI group performed 10 standing headers, the leg impact group performed 10 soccer ball trapping maneuvers over 10 min, and the control group did not participate in any soccer drills. Plasma was collected before testing and 24 h afterward, and sEVs were isolated and characterized via nanoparticle tracking analysis. Next-generation sequencing was utilized to identify candidate miRNAs isolated from sEVs, and candidate microRNAs were analyzed via quantitative polymerase chain reaction. In silico target prediction was performed using TargetScan (Version 7.0; targetscan.org) and miRWalk (http://mirwalk.umm.uni-heidelberg.de/) programs, and target validation was performed using luciferase reporter vectors with a miR-7844-5p mimic in human embryonic kidney (HEK) 293T/17 cells.ResultsPlasma sEV concentration and size were not affected across time and group following repetitive HI exposure. After 24 h, the HI read count from next-generation sequencing showed a 4-fold or greater increase in miR-92b-5p, miR-423-5p, and miR-24-3p and a 3-fold or greater decrease in miR-7844-5p, miR-144-5p, miR-221-5p, and miR-22-3p. Analysis of quantitative polymerase chain reaction revealed that leg impact did not alter the candidate miRNA levels. To our knowledge, miR-7844-5p is a previously unknown miRNA. We identified 8 miR-7844-5p mRNA targets: protein phosphatase 1 regulatory inhibitor subunit 1B (PPP1R1B), LIM and senescent cell antigen-like domains 1 (LIMS1), autophagy-related 12 (ATG12), microtubule-associated protein 1 light chain 3 beta (MAP1LC3B), integrin subunit alpha-1 (ITGA1), mitogen-activated protein kinase 1 (MAPK1), glycogen synthase kinase 3β (GSK3β), and mitogen-activated protein kinase 8 (MAPK8).ConclusionCollectively, these data indicate repetitive HI exposure alters plasma sEV miRNA content, but not sEV size or number. Furthermore, for the first time we demonstrate that previously unknown miR-7844-5p targets mRNAs known to be involved in mitochondrial apoptosis, autophagy regulation, mood disorders, and neurodegenerative disease.  相似文献   

Handwriting production in Spanish children with dyslexia: spelling or motor difficulties?     

Martínez-García  Cristina  Afonso  Olivia  Cuetos  Fernando  Suárez-Coalla  Paz 《Reading and writing》2021,34(3):565-593

Reading and Writing - Spelling and handwriting are different processes; however, they are learned simultaneously, and numerous studies have shown that they interact. Besides the commonly reported...  相似文献   

Prosody in the reading of children with specific language impairment / La prosodia en la lectura de niños con trastorno específico del lenguaje     

Natalia Jordán  Fernando Cuetos  Paz Suárez-Coalla 《Infancia y Aprendizaje》2019,42(1):87-127

Expressive reading is considered one of the subprocesses involved in reading fluency, and good readers show greater changes in tone and fewer unnecessary pauses than bad ones. Given the high frequency of reading difficulties in specific language impairment (SLI), there may be certain differences in the use of prosody among children with SLI. The purpose of this study was to research whether prosody in the reading of children with Spanish SLI differs from that in the reading of typical readers. To do so, 44 children (SLI and control) read aloud a text which contained declarative, interrogative and exclamatory sentences. Different prosodic parameters referring to length, tone and intensity were measured. The results showed that the children with SLI read slower, commit more errors and make more inappropriate pauses. Furthermore, fewer pitch variations were found in the interrogative sentence and in the final features of the sentence. These results confirm the relationship between decoding and prosody; therefore, interventions with these children should bear in mind the practice of expressive reading while learning reading fluency.  相似文献   

Guest Editorial     

Fernando Almeida Diniz 《欧洲师范教育杂志》1991,14(2):103-105

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