bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drawing Large Graphs by Low‐Rank Stress Majorization
Authors: Khoury Marc , Hu Yifan , Krishnan Shankar , Scheidegger Carlos 
Published: June 2012

AbstractOptimizing a stress model is a natural technique for drawing graphs: one seeks an embedding into Rd which best preserves the induced graph metric. Current approaches to solving the stress model for a graph with |𝒱| nodes and |ɛ| edges require the full all‐pairs shortest paths (APSP) matrix, which takes O(|𝒱|2 log |ɛ|+|𝒱‖ɛ|) time and O(|𝒱|2) space. We propose a novel algorithm based on a low‐rank approximation to the required matrices. The crux of our technique is an observation that it is possible to approximate the full APSP matrix, even when only a small subset of its entries are known. Our algorithm takes time O(k|𝒱|+|𝒱|log|𝒱|+|ɛ|) per iteration with a preprocessing time of O(k3+ k(|ɛ|+|𝒱| log |𝒱|) + k2|𝒱|) and memory usage of O(k|𝒱|), where a user‐defined parameter k trades off quality of approximation with running time and space. We give experimental results which show, to the best of our knowledge, the largest (albeit approximate) full stress model based layouts to date.
Document Thumbnails with Variable Text Scaling
Authors: Stoffel A. , Strobelt H. , Deussen O. , Keim D. A. 
Published: June 2012

AbstractDocument reader applications usually offer an overview of the layout for each page as thumbnail views. Reading the text in these becomes impossible when the font size becomes very small. We improve the readability of these thumbnails using a distortion method, which retains a readable font size of interesting text while shrinking less interesting text further. In contrast to existing approaches, our method preserves the global layout of a page and is able to show context around important terms. We evaluate our technique and show application examples.
A Design Study of Direct‐Touch Interaction for Exploratory 3D Scientific Visualization
Authors: Klein Tijmen , Guéniat Florimond , Pastur Luc , Vernier Frédéric , Isenberg Tobias 
Published: June 2012

AbstractWe present an interaction design study of several non‐overlapping direct‐touch interaction widgets, postures, and bi‐manual techniques to support the needs of scientists who are exploring a dataset. The final interaction design supports navigation/zoom, cutting plane interaction, a drilling exploration, the placement of seed particles in 3D space, and the exploration of temporal data evolution. To ground our design, we conducted a requirements analysis and used a participatory design approach throughout development. We chose simulations in the field of fluid mechanics as our example domain and, in the paper, discuss our choice of techniques, their adaptation to our target domain, and discuss how they facilitate the necessary combination of visualization control and data exploration. We evaluated our resulting interactive data exploration system with seven fluid mechanics experts and report on their qualitative feedback. While we use flow visualization as our application domain, the developed techniques were designed with generalizability in mind and we discuss several implications of our work on further development of direct‐touch data exploration techniques for scientific visualization in general.
Vismon: Facilitating Analysis of Trade‐Offs, Uncertainty, and Sensitivity In Fisheries Management Decision Making
Authors: Booshehrian Maryam , Möller Torsten , Peterman Randall M. , Munzner Tamara 
Published: June 2012

AbstractIn this design study, we present an analysis and abstraction of the data and task in the domain of fisheries management, and the design and implementation of the Vismon tool to address the identified requirements. Vismon was designed to support sophisticated data analysis of simulation results by managers who are highly knowledgeable about the fisheries domain but not experts in simulation software and statistical data analysis. The previous workflow required the scientists who built the models to spearhead the analysis process. The features of Vismon include sensitivity analysis, comprehensive and global trade‐offs analysis, and a staged approach to the visualization of the uncertainty of the underlying simulation model. The tool was iteratively refined through a multi‐year engagement with fisheries scientists with a two‐phase approach, where an initial diverging experimentation phase to test many alternatives was followed by a converging phase where the set of multiple linked views that proved effective were integrated together in a useable way. Several fisheries scientists have used Vismon to communicate with policy makers, and it is scheduled for deployment to policy makers in Alaska.
ConnectedCharts: Explicit Visualization of Relationships between Data Graphics
Authors: Viau C. , McGuffin M. J. 
Published: June 2012

AbstractMultidimensional multivariate data can be visualized using many different well‐known charts, such as bar charts, stacked bar charts, grouped bar charts, scatterplots, or pivot tables, or also using more advanced high‐dimensional techniques such as scatterplot matrices (SPLOMs) or parallel coordinate plots (PCPs). These many techniques have different advantages, and users may wish to use several charts or data graphics to understand a dataset from different perspectives. We present ConnectedCharts, a technique for displaying relationships between multiple charts. ConnectedCharts allow for hybrid combinations of bar charts, scatterplots, and parallel coordinates, with curves drawn to show the conceptual links between charts. The charts can be thought of as coordinated views, where linking is achieved not only through interactive brushing, but also with explicitly drawn curves that connect corresponding data tuples or axes. We present a formal description of a design space of many simple charts, and also identify different kinds of connections that can be displayed between related charts. Our prototype implementation demonstrates how the connections between multiple charts can make relationships clearer and can serve to document the history of a user's analytical process, leading to potential applications in visual analytics and dashboard design.
Importance Driven Automatic Color Design for Direct Volume Rendering
Authors: Wang Lei , Kaufman Arie 
Published: June 2012

AbstractThis paper introduces an automatic color design method that is driven by an importance function of the objects within a volumetric dataset. Our method allows the user to intuitively modify the object classification and the importance distribution function in the 2D rendered image. It automatically computes the transfer function, especially the color distribution, to convey the importance of the objects. In our approach, the importance of an object is represented as the attentiveness of a color. In addition, we preserve the color harmony in the rendered image in order to provide a visually pleasing result. In this paper, we propose a set of computational measurements to compute the color attentiveness and color harmony. Our color assignment algorithm supports arbitrary‐dimensional transfer functions and obtains interactive frame rates. Our method involves three color spaces, namely Coloroid system, CIE LChuv, and Adobe RGB color space. It calculates the color attentiveness in CIE LChuv space, and the color harmony in Coloroid system. It, then, assigns the transfer function in a dual space of Adobe RGB space and renders the resulting image in Adobe RGB space. We conducted a detailed user study, which proves that our method successfully conveys the importance distributions. Our contribution in this paper is not only our importance driven approach, but also our computational measurements and our color assignment algorithm.
A Taxonomy of Visual Cluster Separation Factors
Authors: Sedlmair M. , Tatu A. , Munzner T. , Tory M. 
Published: June 2012

AbstractWe provide two contributions, a taxonomy of visual cluster separation factors in scatterplots, and an in‐depth qualitative evaluation of two recently proposed and validated separation measures. We initially intended to use these measures to provide guidance for the use of dimension reduction (DR) techniques and visual encoding (VE) choices, but found that they failed to produce reliable results. To understand why, we conducted a systematic qualitative data study covering a broad collection of 75 real and synthetic high‐dimensional datasets, four DR techniques, and three scatterplot‐based visual encodings. Two authors visually inspected over 800 plots to determine whether or not the measures created plausible results. We found that they failed in over half the cases overall, and in over two‐thirds of the cases involving real datasets. Using open and axial coding of failure reasons and separability characteristics, we generated a taxonomy of visual cluster separability factors. We iteratively refined its explanatory clarity and power by mapping the studied datasets and success and failure ranges of the measures onto the factor axes. Our taxonomy has four categories, ordered by their ability to influence successors: Scale, Point Distance, Shape, and Position. Each category is split into Within‐Cluster factors such as density, curvature, isotropy, and clumpiness, and Between‐Cluster factors that arise from the variance of these properties, culminating in the overarching factor of class separation. The resulting taxonomy can be used to guide the design and the evaluation of cluster separation measures.
Semi‐Supervised Dimensionality Reduction based on Partial Least Squares for Visual Analysis of High Dimensional Data
Authors: Paiva Jose Gustavo S. , Schwartz William Robson , Pedrini Helio , Minghim Rosane 
Published: June 2012

AbstractDimensionality reduction is employed for visual data analysis as a way to obtaining reduced spaces for high dimensional data or to mapping data directly into 2D or 3D spaces. Although techniques have evolved to improve data segregation on reduced or visual spaces, they have limited capabilities for adjusting the results according to user's knowledge. In this paper, we propose a novel approach to handling both dimensionality reduction and visualization of high dimensional data, taking into account user's input. It employs Partial Least Squares (PLS), a statistical tool to perform retrieval of latent spaces focusing on the discriminability of the data. The method employs a training set for building a highly precise model that can then be applied to a much larger data set very effectively. The reduced data set can be exhibited using various existing visualization techniques. The training data is important to code user's knowledge into the loop. However, this work also devises a strategy for calculating PLS reduced spaces when no training data is available. The approach produces increasingly precise visual mappings as the user feeds back his or her knowledge and is capable of working with small and unbalanced training sets.
Tracing Tuples Across Dimensions: A Comparison of Scatterplots and Parallel Coordinate Plots
Authors: Kuang X. , Zhang H. , Zhao S. , McGuffin M.J. 
Published: June 2012

AbstractOne of the fundamental tasks for analytic activity is retrieving (i.e., reading) the value of a particular quantity in an information visualization. However, few previous studies have compared user performance in such value retrieval tasks for different visualizations. We present an experimental comparison of user performance (time and error distance) across four multivariate data visualizations. Three variants of scatterplot (SCP) visualizations, namely SCPs with common vertical axes (SCP‐common), SCPs with a staircase layout (SCP‐staircase), and SCPs with rotated axes between neighboring cells (SCP‐rotated), and a baseline parallel coordinate plots (PCP) were compared. Results show that the baseline PCP is better than SCP‐rotated and SCP‐staircase under all conditions, while the difference between SCP‐common and PCP depends on the dimensionality and density of the dataset. PCP shows advantages over SCP‐common when the dimensionality and density of the dataset are low, but SCP‐common eventually outperforms PCP as data dimensionality and density increase. The results suggest guidelines for the use of SCPs and PCPs that can benefit future researchers and practitioners.
Do Non-Response Follow-Ups Improve or Reduce Data Quality?: A Review of the Existing Literature
Authors: Olson Kristen 
Published: June 2012

SummaryThe paper systematically reviews existing literature on the relationship between the level of effort to recruit a sampled person and the measurement quality of survey data. Hypotheses proposed for this relationship are reviewed. Empirical findings for the relationship between level of effort as measured by paradata (the number of follow-up attempts, refusal conversion and time in the field) and question-specific item non-response rates, aggregate measures of item non-response rates, response accuracy and various measurement errors on attitudinal questions are examined through a qualitative review.
The Efficiency of Performance‐Based Fee Funds
Authors: Díaz‐Mendoza Ana C. , López‐Espinosa Germán , Martínez Miguel A. 
Published: June 2012

AbstractThis paper compares the efficiency of mutual funds that charge management fees based totally or partially on returns (performance) with those that charge them exclusively on assets under management. We analyse Spanish risky mutual funds during 1999–2009 for which both types of management fees are authorised. We find that performance‐based fee funds perform significantly better than the other risky funds considered. Moreover, a strongly positive performance‐expenses relation is found for such funds, and negative for the other. These results seem to indicate more efficient management in performance‐based fee funds, in contrast with their low presence in the fund industry.
Eosinophilic annular erythema is a peculiar subtype in the spectrum of Wells syndrome: a multicentre long‐term follow‐up study
Authors: El‐Khalawany M. , Al‐Mutairi N. , Sultan M. , Shaaban D. 
Published: June 2012

AbstractBackground/Objective  Eosinophilic annular erythema (EAE) was proposed to describe annular skin lesions associated with tissue eosinophilia, however, its relation to Well’s syndrome (WS) remains a source of controversy. We studied a series of patients to increase awareness of this entity and to clarify its relation to WS.Methods  A multicentre study in which the clinical records, histological findings, laboratory results, therapeutic responses and follow‐up of 10 patients were demonstrated.Results  The study included seven women and three men with age ranging from 31 to 54 years. The duration of the disease ranged from 3 to 28 months. All patients showed involvement of trunk and extremities. Early lesions were manifested as erythematous plaques, which progressed to well‐developed figurate lesions and ended as large annular lesions with pigmented centre and elevated border. Flame figures were only observed in well‐developed and long‐standing lesions. Blood eosinophilia was found in all patients with different grades. Associated disorders included chronic gastritis, diabetes mellitus, chronic hepatitis‐C virus infection and chronic kidney disease. The disease showed chronic course with high relapse rate and resistance to various therapeutic modalities including systemic steroid alone and in combination with hydroxychloroquine and cyclosporine.Conclusion  We believe that EAE is a peculiar clinical variant in the spectrum of WS, which is characterized by a chronic course, resistance to treatment and high relapse rate. The diagnosis and evaluation of this condition need a close monitoring with repeated clinical, histological and laboratory assessment.
Psoriasis and cardiovascular risk. Assessment by different cardiovascular risk scores
Authors: Fernández‐Torres R. , Pita‐Fernández S. , Fonseca E. 
Published: June 2012

AbstractBackground:  Psoriasis is an inflammatory disease associated with an increased risk of cardiovascular morbidity and mortality. However, very few studies determine cardiovascular risk by means of Framingham risk score or other indices more appropriate for countries with lower prevalence of cardiovascular risk factors.Objectives  To determine multiple cardiovascular risk scores in psoriasis patients, the relation between cardiovascular risk and psoriasis features and to compare our results with those in the literature.Methods  We assessed demographic data, smoking status, psoriasis features, blood pressure and analytical data. Cardiovascular risk was determined by means of Framingham, SCORE, DORICA and REGICOR scores.Results  A total of 395 patients (59.7% men and 40.3% women) aged 18–86 years were included. The proportion of patients at intermediate and high risk of suffering a major cardiovascular event in the next 10 years was 30.5% and 11.4%, respectively, based on Framingham risk score; 26.9% and 2.2% according to DORICA and 6.8% and 0% using REGICOR score. According to the SCORE index, 22.1% of patients had a high risk of death due to a cardiovascular event over the next 10 years. Cardiovascular risk was not related to psoriasis characteristics, except for the Framingham index, with higher risk in patients with more severe psoriasis (P = 0.032).Conclusions  A considerable proportion of patients had intermediate or high cardiovascular risk, without relevant relationship with psoriasis characteristics and treatment schedules. Therefore, systematic evaluation of cardiovascular risk scores in all psoriasis patients could be useful to identify those with increased cardiovascular risk, subsidiary of lifestyle changes or therapeutic interventions.
Xer‐cise in Helicobacter pylori: One‐step Transformation for the Construction of Markerless Gene Deletions
Authors: Debowski Aleksandra W. , Gauntlett Jonathan C. , Li Hong , Liao Tingting , Sehnal Miriam , Nilsson Hans‐Olof , Marshall Barry J. , Benghezal Mohammed 
Published: June 2012

AbstractBackgroundXer‐cise is an efficient selectable marker removal technique that was first applied in
Bacillus subtilis and
Escherichia coli for the construction of markerless gene deletions. Xer‐cise marker excision takes advantage of the presence of site‐specific Xer recombination in most bacterial species for the resolution of chromosome dimers at the dif site during replication. The identification and functional characterization of the difH/XerH recombination system enabled the development of Xer‐cise in
Helicobacter pylori.MethodsMarkerless deletions were obtained by a single natural transformation step of the Xer‐cise cassette containing rpsL
and cat genes, for streptomycin susceptibility and chloramphenicol resistance respectively, flanked by difH
sites and neighboring homologous sequences of the target gene. Insertion/deletion recombinant
H. pylori were first selected on chloramphenicol‐containing medium followed by selection on streptomycin‐containing medium for clones that underwent XerH mediated excision of the rpsL‐cat cassette, resulting in a markerless deletion.Results
XerH‐mediated removal of the antibiotic marker was successfully applied in three different
H. pylori strains to obtain markerless gene deletions at very high efficiencies. An unmarked triple deletion mutant was also constructed by sequential deletion of ureA, vacA
and HP0366 and removal of the selectable marker at each step. The triple mutant had no growth defect suggesting that multiple difH
sites per chromosome can be tolerated without affecting bacterial fitness.ConclusionXer‐cise eliminates the need for multiple passages on non selective plates and subsequent screening of clones for loss of the antibiotic cassette by replica plating.
Transfusion reactions: a comparative observational study of blood components produced before and after implementation of semiautomated production from whole blood
Authors: Semple Elisabeth , Bowes‐Schmidt Audrey , Yi Qi‐Long , Shimla Susan , Devine Dana V. 
Published: June 2012

BACKGROUND: A semiautomated method of component production from whole blood was implemented at Canadian Blood Services. To assess safety of the new components, the frequency of adverse transfusion events (ATEs) to platelet components (PCs) and red blood cell (RBCs) produced before and after implementation of the new method was surveyed and compared.STUDY DESIGN AND METHODS: This retrospective, observational, noninferiority study was conducted in 12 sentinel hospitals across Canada. The control group received RBCs in additive solution‐3 (AS‐3) and platelet‐rich plasma (PRP)‐produced platelets (PLTs) for 3 to 11 months before implementation of semiautomated production, and the study group received RBCs in saline‐adenine‐glucose‐mannitol (SAGM) and buffy coat (BC)‐produced PLTs for 3 to 11 months after implementation. ATE definitions at each hospital and standard practice for reporting did not change between control and study periods. Data for analysis were obtained from databases and original report forms.RESULTS: The pooled risk ratio of a reaction to SAGM versus AS‐3 RBCs was 0.77 (95% confidence interval [CI], 0.66‐0.90), suggesting that SAGM products had significantly lower reaction rates than AS‐3 products (p < 0.01). Reported allergic reactions to RBCs decreased from 0.07% (AS‐3) to 0.04% (SAGM). For PLTs, the difference in reaction rates between BC and PRP was not significant (p = 0.37), and the pooled risk ratio of BC versus PRP was 1.14 (95% CI, 0.86‐1.50).CONCLUSION: The change in manufacturing method was associated with lower reaction rates to SAGM RBCs than to AS‐3 RBCs. Pooled BC PLTs were noninferior to random‐donor PRP PLTs with respect to ATEs.
Heterogeneity of F cells in β‐thalassemia
Authors: Prus Eugenia , Fibach Eitan 
Published: June 2012

BACKGROUND: Fetal hemoglobin (HbF), which is largely replaced after birth by the adult Hb, is concentrated in a few “F cells.” Their number significantly increases in certain physiologic and clinical situations, including in β‐thalassemia (β‐thal). Their quantification is used to detect fetal–maternal hemorrhage (FMH), where fetal cells enter the maternal circulation. We were confronted with a pregnant woman with β‐thal who was suspected to have FMH. To establish the usefulness of a flow cytometric procedure to differentiate between fetal cells and the maternal F cells, we screened adult β‐thal patients.STUDY DESIGN AND METHODS: Blood samples were simultaneously stained with fluorescent antibodies to HbF and to carbonic anhydrase (CA) isotype II, which is specific to adult red blood cells (RBCs).RESULTS: A heterogeneous distribution of RBCs with respect to HbF and CA expression was observed: adult non‐F cells (CA+HbF–) and F cells (CA+HbF+/HbF++) as well as F cells with characteristics of fetal cells (CA–HbF++).CONCLUSIONS: The presence of CA–HbF++ RBCs in nonpregnant women, and even men, with thal indicates that the CA/HbF method is inappropriate for detection of FMH. The coexistence of F cells carrying fetal or adult markers suggests that they originate from two types of stem cell, adult and fetal, lineages. Normally, the fetal lineage is insignificant, but in β‐thal, as HbF‐containing RBCs have a selective advantage, the “fetal” lineage gains significance.
Risk Taking and Performance of Public Insurers: An International Comparison
Authors: Fields L. Paige , Gupta Manu , Prakash Puneet 
Published: June 2012

AbstractWe investigate how investor protection, government quality, and contract enforcement affect risk taking and performance of insurance companies from around the world. We find that better investor protection results in less risk taking, as do higher quality government and greater contract enforceability. However, we find only limited evidence that these factors influence firm performance. We conclude that better overall operating environments result in less risk taking by insurers without the concomitant decline in performance. These results imply that better investor protection environments benefit policyholders and outside stockholders by preventing corporate insiders from expropriating wealth from policyholders and outside stockholders.