209 research outputs found

    How to project a bipartite network?

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    The one-mode projecting is extensively used to compress the bipartite networks. Since the one-mode projection is always less informative than the bipartite representation, a proper weighting method is required to better retain the original information. In this article, inspired by the network-based resource-allocation dynamics, we raise a weighting method, which can be directly applied in extracting the hidden information of networks, with remarkably better performance than the widely used global ranking method as well as collaborative filtering. This work not only provides a creditable method in compressing bipartite networks, but also highlights a possible way for the better solution of a long-standing challenge in modern information science: How to do personal recommendation?Comment: 7 pages, 4 figure

    Host--parasite models on graphs

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    The behavior of two interacting populations, ``hosts''and ``parasites'', is investigated on Cayley trees and scale-free networks. In the former case analytical and numerical arguments elucidate a phase diagram, whose most interesting feature is the absence of a tri-critical point as a function of the two independent spreading parameters. For scale-free graphs, the parasite population can be described effectively by Susceptible-Infected-Susceptible-type dynamics in a host background. This is shown both by considering the appropriate dynamical equations and by numerical simulations on Barab\'asi-Albert networks with the major implication that in the termodynamic limit the critical parasite spreading parameter vanishes.Comment: 10 pages, 6 figures, submitted to PRE; analytics redone, new calculations added, references added, appendix remove

    Pseudoexons provide a mechanism for allele-specific expression of APC in familial adenomatous polyposis

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    Allele-specific expression (ASE) of the Adenomatous Polyposis Coli (APC) gene occurs in up to one-third of families with adenomatous polyposis (FAP) that have screened mutation-negative by conventional techniques. To advance our understanding of the genomic basis of this phenomenon, 54 APC mutation-negative families (21 with classical FAP and 33 with attenuated FAP, AFAP) were investigated. We focused on four families with validated ASE and scrutinized these families by sequencing of the blood transcriptomes (RNA-seq) and genomes (WGS). Three families, two with classical FAP and one with AFAP, revealed deep intronic mutations associated with pseudoexons. In all three families, intronic mutations (c.646-1806T > G in intron 6, c.1408+729A > G in intron 11, and c.1408+731C > T in intron 11) created new splice donor sites resulting in the insertion of intronic sequences (of 127 bp, 83 bp, and 83 bp, respectively) in the APC transcript. The respective intronic mutations were absent in the remaining polyposis families and the general population. Premature stop of translation as the predicted consequence as well as co-segregation with polyposis supported the pathogenicity of the pseudoexons. We conclude that next generation sequencing on RNA and genomic DNA is an effective strategy to reveal and validate pseudoexons that are regularly missed by traditional screening methods and is worth considering in apparent mutation-negative polyposis families.Instituto Multidisciplinario de Biología Celula

    Correlations in Bipartite Collaboration Networks

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    Collaboration networks are studied as an example of growing bipartite networks. These have been previously observed to have structure such as positive correlations between nearest-neighbour degrees. However, a detailed understanding of the origin of this phenomenon and the growth dynamics is lacking. Both of these are analyzed empirically and simulated using various models. A new one is presented, incorporating empirically necessary ingredients such as bipartiteness and sublinear preferential attachment. This, and a recently proposed model of team assembly both agree roughly with some empirical observations and fail in several others.Comment: 13 pages, 17 figures, 2 table, submitted to JSTAT; manuscript reorganized, figures and a table adde

    Academic experience satisfaction of pharmacy and dentistry students

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    Objective: To assess the psychometric properties of the Academic Experience Satisfaction Scale (ESEA) applied to Pharmacy and Dentistry students and investigate the effect of demographic and course-related characteristics on the ESEA factors. Methods: This was a cross-sectional study. Academic satisfaction was assessed by the ESEA. Construct validity was measured by confirmatory factor analysis (CFI, TLI, RMSEA). The composite reliability (CR) and the ordinal α were estimated. Structural model was elaborated considering demographic and course-related characteristics as the independent variable and ESEA factors as the dependent variables. The model fit and path estimates significance (β) were evaluated (z test; α = 5%). Results: 544 students participated in the study (70.0% female; mean age: 21.4 ± 2.4 years; 52.4% dental students). ESEA showed adequate fit to the data (CFI = 0.90; TLI = 0.90; RMSEA = 0.064, CR and α ≥ 0.88). In general, students reported being satisfied with their academic experience. Dental students and those from the first and second years of the course showed greater satisfaction with the academic experience. Sex did not have a significant impact on any of the scale's factors. Conclusion: ESEA produced valid and reliable data. Course-related characteristics, but not demographic characteristics, significantly affected the academic experience of students.info:eu-repo/semantics/publishedVersio

    Early diagnosis of temporomandibular joint involvement in juvenile idiopathic arthritis: a pilot study comparing clinical examination and ultrasound to magnetic resonance imaging

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    Objectives. To study the validity of both rheumatological and orthodontic examinations and ultrasound (US) as screening methods for early diagnosis of TMJ arthritis against the gold standard MRI. Methods. Thirty consecutive juvenile idiopathic arthritis (JIA) patients were included in this pilot study. Rheumatological and orthodontic examinations as well as US were performed within 1 month of the MRI in a blinded fashion. Joint effusion and/or increased contrast enhancement of synovium or bone were considered signs of active arthritis on MRI. Results. A total of 19/30 (63%) patients and 33/60 (55%) joints had signs of TMJ involvement on MRI. This was associated with condylar deformity in 9/19 (47%) patients and 15/33 (45%) joints. Rheumatological, orthodontic and US examinations correctly diagnosed 11 (58%), 9 (47%) and 6 (33%) patients, respectively, with active TMJ arthritis, but misdiagnosed 8 (42%), 10 (53%) and 12 (67%) patients, respectively, as having no signs of inflammation. The best predictor for active arthritis on MRI was a reduced maximum mouth opening. Conclusion. None of the methods tested was able to reliably predict the presence or absence of MRI-proven inflammation in the TMJ in our cohort of JIA patients. US was the least useful of all methods tested to exclude active TMJ arthriti

    Impact of body and orofacial appearance on life satisfaction among Brazilian adults

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    Aims 1. to elaborate a general model of physical appearance taking into account body image (BI) and orofacial appearance (OA) components; and 2. to evaluate the impact of BI and OA on life satisfaction among Brazilian adults. Methods This is a cross-sectional observational study. The cognitive, behavioral, affective, and satisfaction/ dissatisfaction aspects of BI, the satisfaction and psychosocial impact of OA, and life satisfaction were evaluated by self-reported psychometric scales. Principal Component Analysis and Parallel Analysis were performed. Structural equation models were elaborated to estimate the impact of BI and OA on life satisfaction. The fit of the models was verified and the significance of the path estimates (β) was evaluated using z-tests (α = 5%). Results A total of 1,940 individuals participated in the study (age: mean = 24.8, standard deviation = 5.7 years; females = 70.1%). In the male sample, three physical appearance factors were retained (OA, cognitive and behavioral components of BI, and affective and satisfaction/dissatisfaction components of BI). In the female sample, two factors were retained (OA and all components of BI). All factors had significant impact on life satisfaction (β = |0.26|-|0.48|, p<0.001) in both samples. Individuals dissatisfied with BI and OA had lower levels of life satisfaction. For men, the affective and satisfaction components of BI had a greater impact on life satisfaction (β = 0.48, p<0.001) than the other factors (β =] -0.30;-0.25[, p<0.001). For women, both BI and OA had a similar impact (BI: β = -0.30, p<0.001; OA: β = -0.32, p<0.001). Conclusion BI and OA formed distinct clusters in the physical appearance evaluation. Physical appearance was perceived differently by men and women, fostering discussion about the sociocultural construction of the body. BI and OA had a significant impact on life satisfaction and should be considered in assessment and treatment protocols.info:eu-repo/semantics/publishedVersio

    Assessing the length of the mandibular ramus and the condylar process: a comparison of OPG, CBCT, CT, MRI, and lateral cephalometric measurements

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    SummaryBackground/Objectives: To compare different imaging procedures [cone beam computed tomography (CBCT), computed tomography (CT), magnetic resonance imaging (MRI), orthopantomography (OPG), and lateral cephalometry (LC)] for assessing the mandibular height [ramus height (RH)] and condylar process (CondProc) length as they reflect mandibular growth. Materials/Methods: The RH and CondProc of eight cadaver heads (each side separately) were measured using CBCT, CT, MRI, OPG, and LC. They were measured twice by two independent observers parallel to the posterior border of the mandibular ramus. An intraclass correlation coefficient (ICC) was used to assess the inter- and intraobserver reliability. The coefficient of variation was used to elucidate precision. Bland-Altman (BA) plots were used to assess the agreement between the procedures and the intra- and interobserver measurements. Results: All procedures, with the exception of LC, showed good intra- and interobserver agreement (maximum range of agreement: 5.3mm) and excellent reliability (ICC > 0.9). The BA plot analysis for the CondProc and RH showed similar ranges of agreement between MRI, CT, and CBCT (maximum 6.4mm) but higher ranges for OPG and LC. The MRI and OPG values were generally smaller. Conclusions/Implications: All 3D imaging procedures yielded nearly equal results when used to measure the CondProc and RH. MRI is recommended because it avoids ionizing radiation and has higher sensitivity in the detection of inflammation. A 2-year threshold for detecting growth in the follow-up period should be taken into account for all 3D imaging methods. Measuring the RH is recommended for the follow-up of condylar growth because reference values for annual increments are publishe

    On the Number of Closed Factors in a Word

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    A closed word (a.k.a. periodic-like word or complete first return) is a word whose longest border does not have internal occurrences, or, equivalently, whose longest repeated prefix is not right special. We investigate the structure of closed factors of words. We show that a word of length nn contains at least n+1n+1 distinct closed factors, and characterize those words having exactly n+1n+1 closed factors. Furthermore, we show that a word of length nn can contain Θ(n2)\Theta(n^{2}) many distinct closed factors.Comment: Accepted to LATA 201
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