Modeling the evolution of item rating networks using time-domain preferential attachment

The understanding of the structure and dynamics of the intricate network of connections among people that consumes products through Internet appears as an extremely useful asset in order to study emergent properties related to social behavior. This knowledge could be useful, for example, to improve the performance of personal recommendation algorithms. In this contribution, we analyzed five-year records of movie-rating transactions provided by Netflix, a movie rental platform where users rate movies from an online catalog. This dataset can be studied as a bipartite user-item network whose structure evolves in time. Even though several topological properties from subsets of this bipartite network have been reported with a model that combines random and preferential attachment mechanisms [Beguerisse Díaz et al., 2010], there are still many aspects worth to be explored, as they are connected to relevant phenomena underlying the evolution of the network. In this work, we test the hypothesis that bursty human behavior is essential in order to describe how a bipartite user-item network evolves in time. To that end, we propose a novel model that combines, for user nodes, a network growth prescription based on a preferential attachment mechanism acting not only in the topological domain (i.e. based on node degrees) but also in time domain. In the case of items, the model mixes degree preferential attachment and random selection. With these ingredients, the model is not only able to reproduce the asymptotic degree distribution, but also shows an excellent agreement with the Netflix data in several time-dependent topological properties.

Determination of spectral variations by means of component cells useful for CPV rating and design

A methodology is presented to determine both the short-term and the long-term influence of the spectral variations on the performance of Multi-Junction (MJ) solar cells and Concentrating "This is the peer reviewed version of the following article: R. Núñez, C. Domínguez, S. Askins, M. Victoria, R. Herrero, I. Antón, and G. Sala, “Determination of spectral variations by means of component cells useful for CPV rating and design,” Prog. Photovolt: Res. Appl., 2015., which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/pip.2715/full. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving [http://olabout.wiley.com/WileyCDA/Section/id-820227.html#terms]." Photovoltaic (CPV) modules. Component cells with the same optical behavior as MJ solar cells are used to characterize the spectrum. A set of parameters, namely Spectral Matching Ratios (SMRs), is used to characterize spectrally a particular Direct Normal Irradiance (DNI) by comparison to the reference spectrum (AM1.5D-ASTM-G173-03). Furthermore, the spectrally corrected DNI for a given MJ solar cell technology is defined providing a way to estimate the losses associated to the spectral variations. The last section analyzes how the spectrum evolves throughout a year in a given place and the set of SMRs representative for that location are calculated. This information can be used to maximize the energy harvested by the MJ solar cell throughout the year. As an example, three years of data recorded in Madrid shows that losses lower than 5% are expected due to current mismatch for state-of-the-art MJ solar cells.

Adaptación del BRIEF ("Behavior Rating Inventory of Executive Function") a población española y su utilidad para el diagnóstico del trastorno por déficit de atención-hiperactividad subtipos inatento y combinado

La valoración de las funciones ejecutivas tiene una especial dificultad cuando se intenta llevar a cabo mediante un enfoque tradicional de pruebas neuropsicológicas. Este aspecto es especialmente relevante en la evaluación de funciones ejecutivas en población pediátrica, lo que propició el desarrollo de cuestionarios de conducta como el Behavior Rating Inventory of Executive Function (BRIEF), con el fin de convertirse en una medida ecológica de las alteraciones de funciones ejecutivas. Resulta necesario realizar una adaptación completa de una prueba psicométrica para que ésta pueda ser utilizada en una población diferente para la cual fue diseñada. El BRIEF ha sido utilizado para la valoración de las alteraciones ejecutivas en numerosas patologías, pero destacan los estudios realizados en niños con Trastorno por Déficit de Atención - Hiperactividad (TDAH). El TDAH presenta alteraciones neuropsicológicas que implican especialmente a las funciones ejecutivas, lo que justifica el uso de la prueba en esta patología. Incluso, algunas de las teorías más importantes sobre TDAH apuntan a las alteraciones en inhibición como el síntoma nuclear del trastorno. La existencia de dos subtipos principales en el TDAH (subtipo predominantemente inatento y combinado) podría implicar un patrón diferente de alteraciones ejecutiva en cada tipo. OBJETIVOS: Se presentan dos objetivos principales: 1) Adaptación del BRIEF a población española, y 2) Estudio del perfil diferencial del BRIEF entre los subtipos inatento y combinado del TDAH...

Validation of a Spanish Version of the Lille Apathy Rating Scale for Parkinson’s Disease

Introduction. To date, no rating scales for detecting apathy in Parkinson’s disease (PD) patients have been validated in Spanish. For this reason, the aim of this study was to validate a Spanish version of Lille apathy rating scale (LARS) in a cohort of PD patients from Spain. Participants and Methods. 130 PD patients and 70 healthy controls were recruited to participate in the study. Apathy was measured using the Spanish version of LARS and the neuropsychiatric inventory (NPI). Reliability (internal consistency, test-retest, and interrater reliability) and validity (construct, content, and criterion validity) were measured. Results. Interrater reliability was 0.93. Cronbach’s α for LARS was 0.81. The test-retest correlation coefficient was 0.97. The correlation between LARS and NPI scores was 0.61. The optimal cutoff point under the ROC curve was , whereas the value derived from healthy controls was . The prevalence of apathy in our population tested by LARS was 42%. Conclusions. The Spanish version of LARS is a reliable and useful tool for diagnosing apathy in PD patients. Total LARS score is influenced by the presence of depression and cognitive impairment. However, both disorders are independent identities with respect to apathy. The satisfactory reliability and validity of the scale make it an appropriate instrument for screening and diagnosing apathy in clinical practice or for research purposes.

Characterization of rock slopes through slope mass rating using 3D point clouds

Rock mass classification systems are widely used tools for assessing the stability of rock slopes. Their calculation requires the prior quantification of several parameters during conventional fieldwork campaigns, such as the orientation of the discontinuity sets, the main properties of the existing discontinuities and the geo-mechanical characterization of the intact rock mass, which can be time-consuming and an often risky task. Conversely, the use of relatively new remote sensing data for modelling the rock mass surface by means of 3D point clouds is changing the current investigation strategies in different rock slope engineering applications. In this paper, the main practical issues affecting the application of Slope Mass Rating (SMR) for the characterization of rock slopes from 3D point clouds are reviewed, using three case studies from an end-user point of view. To this end, the SMR adjustment factors, which were calculated from different sources of information and processes, using the different softwares, are compared with those calculated using conventional fieldwork data. In the presented analysis, special attention is paid to the differences between the SMR indexes derived from the 3D point cloud and conventional field work approaches, the main factors that determine the quality of the data and some recognized practical issues. Finally, the reliability of Slope Mass Rating for the characterization of rocky slopes is highlighted.

Validation of the Spanish version of mackey childbirth satisfaction rating scale

Background: The “Mackey Childbirth Satisfaction Rating Scale” (MCSRS) is a complete non-validated scale which includes the most important factors associated with maternal satisfaction. Our primary purpose was to describe the internal structure of the scale and validate the reliability and validity of concept of its Spanish version MCSRS-E. Methods: The MCSRS was translated into Spanish, back-translated and adapted to the Spanish population. It was then administered following a pilot test with women who met the study participant requirements. The scale structure was obtained by performing an exploratory factorial analysis using a sample of 304 women. The structures obtained were tested by conducting a confirmatory factorial analysis using a sample of 159 women. To test the validity of concept, the structure factors were correlated with expectations prior to childbirth experiences. McDonald’s omegas were calculated for each model to establish the reliability of each factor. The study was carried out at four University Hospitals; Alicante, Elche, Torrevieja and Vinalopo Salud of Elche. The inclusion criteria were women aged 18–45 years old who had just delivered a singleton live baby at 38–42 weeks through vaginal delivery. Women who had difficulty speaking and understanding Spanish were excluded. Results: The process generated 5 different possible internal structures in a nested model more consistent with the theory than other internal structures of the MCSRS applied hitherto. All of them had good levels of validation and reliability. Conclusions: This nested model to explain internal structure of MCSRS-E can accommodate different clinical practice scenarios better than the other structures applied to date, and it is a flexible tool which can be used to identify the aspects that should be changed to improve maternal satisfaction and hence maternal health.

Minorities and women as government contractors : a report of the United States Commission on Civil Rights.

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The development and evaluation of a prototype grade severity rating system. Final report.

Federal Highway Administration, Washington, D.C.

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Privacy Act of 1974 has little impact on federal contractors.

Mode of access: Internet.

A bibliography of mental tests and rating scales.

Mode of access: Internet.

Employment of retired commissioned officers by contractors of the Department of Defense and the Armed Forces : report (to accompany H.R. 10959)

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Mechanics of style : a guide for solid waste management authors, secretaries, grantees, and contractors /

Mode of access: Internet.

Investigation of punchability tests for electrical steels. [Final report on development of a punchability rating method for electrical steels, for the Research Fund of American Society of Tool and Manufacturing Engineers,

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