A hybrid recommendation approach for a tourism system

Many current e-commerce systems provide personalization when their content is shown to users. In this sense, recommender systems make personalized suggestions and provide information of items available in the system. Nowadays, there is a vast amount of methods, including data mining techniques that can be employed for personalization in recommender systems. However, these methods are still quite vulnerable to some limitations and shortcomings related to recommender environment. In order to deal with some of them, in this work we implement a recommendation methodology in a recommender system for tourism, where classification based on association is applied. Classification based on association methods, also named associative classification methods, consist of an alternative data mining technique, which combines concepts from classification and association in order to allow association rules to be employed in a prediction context. The proposed methodology was evaluated in some case studies, where we could verify that it is able to shorten limitations presented in recommender systems and to enhance recommendation quality

Fatores de motivação dos enfermeiros em cuidados de saúde primários

Introdução: A motivação dos enfermeiros é fundamental para uma maior produtividade, eficiência e qualidade dos cuidados prestados e por isso é tão importante para a gestão em enfermagem. Objetivos: Compreender os fatores motivacionais dos enfermeiros de um Agrupamento de Centros de Saúde da região de Lisboa. Metodologia: Estudo de caso de natureza qualitativa, exploratório-descritivo. A recolha de dados teve por base a entrevista semiestruturada, realizada a nove enfermeiros de um Agrupamento de Centros de Saúde da região de Lisboa. Para garantir uma maior variedade e riqueza dos dados, foram selecionados enfermeiros de diferentes tipologias de unidades funcionais. O número de participantes foi determinado seguido o critério de saturação das respostas. As entrevistas gravadas foram transcritas na íntegra, e analisadas através da análise de conteúdo. Resultados: Os resultados do estudo indicam que os principais fatores de motivação dos enfermeiros são: as recompensas, o desenvolvimento da carreira de enfermagem, o reconhecimento, o local de trabalho/ambiente da prática, o financiamento baseado no desempenho, a liderança e a realização profissional. O fator desenvolvimento de carreira foi o de maior importância. O financiamento baseado no desempenho foi o fator a que a maioria dos participantes atribuiu menor importância enquanto fator de motivação. Conclusão: Os fatores motivacionais dos participantes, vão ao encontro do que é descrito na literatura para outros contextos. Verificou-se que o significado e a importância atribuída aos diferentes fatores é variável de participante para participante, o que realça a individualidade de cada um, motivado por necessidades próprias. Mais estudos sobre a motivação dos enfermeiros devem ser realizados, nomeadamente em Cuidados de Saúde Primários (CSP), onde se verifica escassez de evidência científica.ntroduction: Nurses’ motivation is fundamental for increase productivity, efficiency and quality of nursing care and that is why it is so important for nursing management. Objectives: To understand the motivational factors of nurses in a group of health centres in the Lisbon region. Methodology: Qualitative, exploratory-descriptive case study. Data collection was based on a semi-structured interview, conducted with nine nurses from a Group of Health Centres in the Lisbon region. To ensure a greater variety and richness of data, nurses were selected from different types of functional units. The number of participants was determined following the response saturation criterion. The recorded interviews were transcribed in full, and analysed through content analysis. Results: The results of the study indicate that the main motivating factors for nurses are: rewards, career development, recognition, workplace / work environment, performance- 28 Pensar Enfermagem|Vol. 24 | N.º 1 | 1º Semestre de 2020based financing, leadership and professional achievement, being that career development was the factor to which the participants attributed greater importance and performance-based financing the factor to which the majority of the participants attributed less importance as a motivational factor. Conclusion:The motivational factors of the participants are in line with what is described in the literature for other contexts. It was found that the meaning and importance attributed to the different factors varies from participant to participant, which highlights the individuality of each one, motivated by their own needs. Further studies on the motivation of nurses should be carried out, namely in Primary Health Care (PHC), where there is a shortage of scientific content.info:eu-repo/semantics/publishedVersio

Massive open star clusters using the VVV survey II. Discovery of six clusters with Wolf-Rayet stars

Context: The ESO Public Survey "VISTA Variables in the V\'ia L\'actea" (VVV) provides deep multi-epoch infrared observations for an unprecedented 562 sq. degrees of the Galactic bulge, and adjacent regions of the disk. In this survey nearly 150 new open clusters and cluster candidates have been discovered. Aims: This is the second in a series of papers about young, massive open clusters observed using the VVV survey. We present the first study of six recently discovered clusters. These clusters contain at least one newly discovered Wolf-Rayet (WR) star. Methods: Following the methodology presented in the first paper of the series, wide-field, deep JHKs VVV observations, combined with new infrared spectroscopy, are employed to constrain fundamental parameters for a subset of clusters. Results: We affirm that the six studied stellar groups are real young (2-7 Myr) and massive (between 0.8 and 2.2 10^3 Msol) clusters. They are highly obscured (Av ~ 5-24 mag) and compact (1-2 pc). In addition to WR stars, two of the six clusters also contain at least one red supergiant star. We claim the discovery of 8 new WR stars, and 3 stars showing WR-like emission lines which could be classified WR or OIf. Preliminary analysis provides initial masses of ~30-50 Msol for the WR stars. Finally,we discuss the spiral structure of the Galaxy using as tracers the six new clusters together with the previously studied VVV clusters.Comment: 17 pages, 8 figurs, accepted in A&

Ultrahard carbon film from epitaxial two-layer graphene

Atomically thin graphene exhibits fascinating mechanical properties, although its hardness and transverse stiffness are inferior to those of diamond. To date, there hasn't been any practical demonstration of the transformation of multi-layer graphene into diamond-like ultra-hard structures. Here we show that at room temperature and after nano-indentation, two-layer graphene on SiC(0001) exhibits a transverse stiffness and hardness comparable to diamond, resisting to perforation with a diamond indenter, and showing a reversible drop in electrical conductivity upon indentation. Density functional theory calculations suggest that upon compression, the two-layer graphene film transforms into a diamond-like film, producing both elastic deformations and sp2-to-sp3 chemical changes. Experiments and calculations show that this reversible phase change is not observed for a single buffer layer on SiC or graphene films thicker than 3 to 5 layers. Indeed, calculations show that whereas in two-layer graphene layer-stacking configuration controls the conformation of the diamond-like film, in a multilayer film it hinders the phase transformation.Comment: Published online on Nature Nanotechnology on December 18, 201

Influence of Ionic Liquids on the Aggregation and Pre-aggregation Phenomena of Asphaltenes in Model Solvent Mixtures by Molecular Dynamics Simulations and Quantum Mechanical Calculations

This work presents a systematic study of asphaltene pre-aggregation phenomena in the absence and in the presence of ionic liquids (ILs) from the family of 1-alkyl-3- methylimidazolium by molecular dynamics simulations. The effects of the alkyl chain length of the cation (studying ILs with alkyl chains between C4 and C10) and of the dimension of the anion (testing chloride and bromide) on the aggregation behavior of asphaltenes have been studied. To correlate the results obtained with the direct interaction between each additive and asphaltene, the latter was investigated both by the analysis of the radial distribution functions obtained by molecular dynamics simulations and quantum mechanical calculations. The DFT method was used to calculate the relative stability of the asphaltene-ionic liquid dimers and also the energy, shape, and spatial distribution of frontier orbitals. It was found that all the ionic liquids studied present a dispersing effect on asphaltene in model solvents, except for mixtures rich in toluene where, in most cases, the opposite effect is observed. This is accompanied by the interaction intensity as measured by radial distribution functions. The effects of the alkyl side chain length of the cation and of the anion radius are subtler, but it seems that the asphaltene dispersion effect increases with the length of the cation’s alkyl side chain and decreases with the radius of the anion; these effects are more clearly observed in the mixtures richer in n-heptane. These trends were corroborated by DFT calculations, which showed that the energetic stability of the asphaltene-additive dimer is as higher as the alkyl chain is longer and the anion is smaller. Preaggregation phenomena were also studied in mixtures containing CO2, which proved to be a precipitating agent as observed experimentally. The relative performances of the IL studied were not altered by the presence of CO2

Dimeric Self-assembling via Hydrogen Bonding and Emissive Behavior of a New Copper (I) Complex

This work describes the synthesis, structural characterization and emissive behavior of a new copper (I) complex based on 1-thiocarbamoyl-5-(4-methoxiphenyl)-3-phenyl-4,5-dihydro-1H-pyrazole ligand. A dimeric self-assembling via hydrogen bonding was determined by analyzing the short contacts present in the solid-state structure by means of X-ray crystallography. The spectroscopic properties were determined using UV-Vis and fluorescence experiments and an interesting behavior as bluish luminescence was assigned mainly to the mixed (MLCT + IL) electronic transitions of the Cu(I)d10 ® (S=C–Nligand) type. The complete characterization of the new copper (I) complex also included elemental analyses and IR spectroscopy. DOI: http://dx.doi.org/10.17807/orbital.v9i1.95