2,772 research outputs found
Overlap Removal of Dimensionality Reduction Scatterplot Layouts
Dimensionality Reduction (DR) scatterplot layouts have become a ubiquitous
visualization tool for analyzing multidimensional data items with presence in
different areas. Despite its popularity, scatterplots suffer from occlusion,
especially when markers convey information, making it troublesome for users to
estimate items' groups' sizes and, more importantly, potentially obfuscating
critical items for the analysis under execution. Different strategies have been
devised to address this issue, either producing overlap-free layouts, lacking
the powerful capabilities of contemporary DR techniques in uncover interesting
data patterns, or eliminating overlaps as a post-processing strategy. Despite
the good results of post-processing techniques, the best methods typically
expand or distort the scatterplot area, thus reducing markers' size (sometimes)
to unreadable dimensions, defeating the purpose of removing overlaps. This
paper presents a novel post-processing strategy to remove DR layouts' overlaps
that faithfully preserves the original layout's characteristics and markers'
sizes. We show that the proposed strategy surpasses the state-of-the-art in
overlap removal through an extensive comparative evaluation considering
multiple different metrics while it is 2 or 3 orders of magnitude faster for
large datasets.Comment: 11 pages and 9 figure
High Fibre Diets and Alzheimer\u27s Disease
The convergence of diet and AD may be related to the effects of phytosterols since plasma cholesterol is closely linked and regulated by phytosterols. Dietary fibre modifications that are low in fat and glucose reduce the risk for AD by not only effecting cell membranes and nutrient sensing G coupled receptors but also by regulating number of nuclear receptors such as histone deacetylases (HDAC) and peroxisome proliferator activated receptors (PPAR) that control glucose, fatty acids and cholesterol and have significant effects on the brain cholesterol homeostasis and amyloidosis. The peripheral sink Aβ hypothesis indicates that the peripheral clearance of Aβ and its regulation by dietary phytosterols is of substantial interest since it may delay hypercholesterolemia and the early onset of amyloid plaque development. Liver disease has been of central importance with aging and programmed cell death pathways. Nutritional therapy has emerged as a novel approach to control appetite and the role of nutrigenomics as an early nutritional therapy may assist genes to delay liver and brain diseases such as Parkinson’s disease (PD) and Huntington’s disease (HD) that are associated with aging. The understanding of phytosterols and the role of these lipids in drug therapy such as cholesterol lowering drugs may provide molecular mechanisms that are involved in the regulation of cell Aβ clearance and metabolism. High fibre diets also contain various fatty acids such as the short chain fatty acids (SCFA) and the understanding of synergistic effects of SCFA and phytosterols in glucose regulation and cholesterol homeostasisis important to our understanding of diet, lifestyle and drugs in relation to peripheral amyloidosis and gene expression that play an early role in the development of AD
Why are some prices stickier than others? Firm-data evidence on price adjustment lags
Infrequent price changes at the firm level are now well documented in the literature. However, a number of issues remain partly unaddressed. This paper contributes to the literature on price stickiness by investigating the lags of price adjustments to different types of shocks. We find that adjustment lags to cost and demand shocks vary with firm characteristics, namely the firm’s cost structure, the type of pricing policy, and the type of good. We also document that firms react asymmetrically to demand and cost shocks, as well as to positive and negative shocks, and that the degree and direction of the asymmetry varies across firms. JEL Classification: C41, D40, E31Firm heterogeneity, Panel-ordered probit, real rigidities, survey data
Understanding Water Equilibration Fundamentals as a Step for Rational Protein Crystallization
Background: Vapor diffusion is the most widely used technique for protein crystallization and the rate of water evaporation plays a key role on the quality of the crystals. Attempts have been made in the past to solve the mass transfer problem governing the evaporation process, either analytically or by employing numerical methods. Despite these efforts, the methods used for protein crystallization remain based on trial and error techniques rather than on fundamental principles. Methodology/Principal Findings: Here we present a new theoretical model which describes the hanging drop method as a function of the different variables that are known to influence the evaporation process. The model is extensively tested against experimental data published by other authors and considering different crystallizing conditions. Aspects responsible for the discrepancies between the existing theories and the measured evaporation kinetics are especially discussed; they include the characterization of vapor-liquid equilibrium, the role of mass transfer within the evaporating droplet, and the influence of the droplet-reservoir distance. Conclusions/Significance: The validation tests show that the proposed model can be used to predict the water evaporation rates under a wide range of experimental conditions used in the hanging drop vapor-diffusion method, with no parameter fitting or computational requirements. This model combined with protein solubility data is expected to become a usefu
Who are the prominent players in the UEFA champions league? : an approach based on network analysis
This study aimed to analyze the centrality levels of elite football players. Tactical positions and
tactical line-ups were considered factors to be used in analyzing the variance in the prominence of
players, measured by social network measures. The best 16 teams from the UEFA Champions league
were analyzed during the entire competition. A total of 109 matches were analyzed for this study.
Significant statistical differences between positions were found in % indegree (p = 0.001; ES = 0.268,
moderate effect), % outdegree (p = 0.001; ES = 0.301, moderate effect) and % betweenness (p = 0.001;
ES = 0.114, minimum effect). No statistical differences between tactical line-ups in % outdegree (p =
1.000; ES = 0.001, no effect) or % indegree (p = 1.000; ES = 0.001, no effect) were found. Central
midfielders had the greatest values of centrality, thus confirming their importance in the linkage process
of the team. Position had great influence on the centrality levels of players.info:eu-repo/semantics/publishedVersio
Simulador de Carga Mecânica, em Tempo Real, para Accionamento Eléctrico
O objectivo deste trabalho Ă© implementar um simulador, em tempo real, de
carga mecânica por forma a aferir os diferentes comportamentos de uma máquina
eléctrica em função do tipo de carga a accionar. O protótipo desenvolvido permite ensaiar
o comportamento de qualquer tipo de máquina rotativa, inserida num accionamento
eléctrico, para vários tipos de carga mecânica. De forma a estudar o comportamento de
uma máquina eléctrica para um conjunto alargado de cargas mecânicas foram
implementadas várias cargas tĂpicas, cujo binário de carga pode depender do tempo ou da
velocidade. SĂŁo apresentadas caracterĂsticas de implementação do sistema desenvolvido,
que faz uso de um travão magnético e de um autómato programável, e resultados
experimentais obtidos para vários tipos de carga
Análise dos IncĂŞndios Florestais num perĂodo de 30 anos (1990-2017). Caso de estudo Concelho de Mação (Portugal)
As mudanças climáticas globais são uma temática de grande destaque na nossa sociedade,
surgindo, inevitavelmente, associado a esta preocupação, o aumento dos gases de efeito de estufa
(GEE) presentes na atmosfera. Segundo Chuvieco et al. (2007) os incĂŞndios florestais sĂŁo
responsáveis por quase 40% das emissões totais de CO2, aumentando significativamente na
contribuição dos GEE na atmosfera. Uma forma de compreender os fluxos associados ao carbono é o
estudo da quantificação da biomassa florestal, que atua como sumidouro. Ao ocorrer um incêndio
florestal, esta dinâmica fica profundamente afetada (Celes et al., 2013).Este artigo é financiado por Fundos Nacionais através da FCT - Fundação para a Ciência e a Tecnologia
no âmbito do projeto UID/SOC/04020/2013.info:eu-repo/semantics/publishedVersio
Outdoor play and interaction skills in early childhood education : approaching for measuring using social network analysis
Over the last decade, researches show evidences that the free play and the outdoor activities have positive impact
on children, namely on social skills’ development as cooperation. However, the study of children interaction,
especially when we want to identify and study a particular type of interaction, like cooperative interaction,
requires a reflexion about the most efficient tolls and methods that can be used. With this article we intend to
present a first reflective review of mathematical techniques and methods that can be potentially useful in the
study of cooperative interactions with children in outdoor free play. Considering the characteristics of outdoor
learning environments, which are based on freedom and free play exploitation of nature, the methods used in
studies of this nature in indoor environment, tend to be more controlled by adults and more spatially limited,
may not be the most effective. We intend to demonstrate that it is necessary to create a combination of
mathematical techniques and methods based on the social network analysis, given the specificity of the
educational outdoor environment or the space level and the dynamics of activities that there are usually
generated.info:eu-repo/semantics/publishedVersio
Identifying the centrality levels of futsal players : a network approach
The aim of this study it was verify the differences of prominence levels between tactical positions in
futsal (indoor football). For that reason, it was performed an analysis of variance between competitive levels and
tactical positions for the centrality metrics computed by using network analysis. Forty-six futsal players from
different competitive levels (U12, U14, U16 and Amateurs) it were analysed during three official futsal matches.
Results revealed no differences in centrality metrics between competitive levels (p = 1.00; = 0.001; very small
effect size) had no significant statistical differences in the centrality metrics. Nevertheless, tactical position (p =
0.001; = 0.593; moderate effect size) had significant main effects on the centrality metrics. Centrality metrics
revealed that defenders are the most prominent players in to receive the ball. By the other hand, defenders and
wings are the positions with greater centralities in to pass the ball for the teammates.info:eu-repo/semantics/publishedVersio
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