1,775 research outputs found

    Full metastable asymptotic of the Fisher information

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    We establish an expansion by Gamma-convergence of the Fisher information relative to the reference measure exp(-beta V), where V is a generic multiwell potential and beta goes to infinity. The expansion reveals a hierarchy of multiple scales reflecting the metastable behavior of the underlying overdamped Langevin dynamics: distinct scales emerge and become relevant depending on whether one considers probability measures concentrated on local minima of V, probability measures concentrated on critical points of V, or generic probability measures on R^d. We thus fully describe the asymptotic behavior of minima of the Fisher information over regular sets of probabilities. The analysis mostly relies on spectral properties of diffusion operators and the related semiclassical Witten Laplacian and covers also the case of a compact smooth manifold as underlying space.Comment: 24 pages. Typos correcte

    Design of an Application to Collect Data and Create Animations from Visual Algorithm Simulation Exercises

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    Visual Algorithm Simulation (VAS) exercises are commonly used in Computer Science education to help learners understand the logic behind the abstractions used in programming. These exercises also present problems common in the daily work of Computer Science graduates. Aalto University uses the JSAV library to create VAS exercises and evaluate the solutions submitted by students. The evaluation process counts the amount of correct steps given by the user during the exercise. However, because more detailed data is not collected, teachers currently can not recreate and analyse the submitted solutions more in depth. This thesis presents the design, development and evaluation of an application prototype, which can be easily integrated in existing VAS exercises created with the JSAV library. The prototype is called Player Application, and it is designed as a service that can be easily integrated into other systems while still remaining independent. The Player Application consists of two main independent components: the Exercise Recorder and the Exercise Player. A third important contribution is the new JSON-based Algorithm Animation Language, which is designed to describe, structure and store the data collected from the VAS exercises. The prototype was successfully tested in an online environment by importing the Exercise Recorder into existing exercises and replaying the submitted solutions in the Exercise Player. The tests showed that its design and architecture were valid. Next, the aim is to create a mature application, which can be used at Aalto University and other institutions, in addition the prototype still needs further development to support more VAS exercise types

    Quantifying and suppressing ranking bias in a large citation network

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    It is widely recognized that citation counts for papers from different fields cannot be directly compared because different scientific fields adopt different citation practices. Citation counts are also strongly biased by paper age since older papers had more time to attract citations. Various procedures aim at suppressing these biases and give rise to new normalized indicators, such as the relative citation count. We use a large citation dataset from Microsoft Academic Graph and a new statistical framework based on the Mahalanobis distance to show that the rankings by well known indicators, including the relative citation count and Google's PageRank score, are significantly biased by paper field and age. Our statistical framework to assess ranking bias allows us to exactly quantify the contributions of each individual field to the overall bias of a given ranking. We propose a general normalization procedure motivated by the z-score which produces much less biased rankings when applied to citation count and PageRank score

    Surface decontamination protocols for surgical treatment of peri-implantitis: A systematic review with meta-analysis

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    OBJECTIVE: To answer the following PICO question: “In patients requiring surgical treatment of peri‐implantitis (P), is any implant surface decontamination protocol (I) superior to others (C) in terms of clinical and radiographic parameters (O)?” METHODS: Randomized clinical trials (RCTs) comparing two or more decontamination protocols as part of the surgical treatment of peri‐implantitis were included. Two authors independently searched for eligible studies, screened titles and abstracts, did full‐text analysis, extracted data, and performed the risk‐of‐bias assessment. Whenever possible, results were summarized through random effects meta‐analyses. RESULTS: Twenty‐two manuscripts reporting on 16 RCTs were included, testing mechanical, chemical and physical decontamination protocols. All of them resulted in an improvement in clinical parameters; however, the superiority of specific protocols over others is mainly based on single RCTs. The use of titanium brushes and implantoplasty showed favorable results as single decontamination methods. Meta‐analyses indicated a lack of added effect of Er:Yag laser on probing pocket depth (PPD) reduction (n = 2, WMD = −0.24 mm, 95% confidence interval [CI] [−1.10; 0.63], p = .59); while systemic antimicrobials (amoxicillin or azithromycin) showed an added effect on treatment success ([PPD ≀5 mm, no bleeding or suppuration, no progressive bone loss]; n = 2, RR = 1.84, 95% CI [1.17;2.91], p = .008), but not in terms of PPD reduction (n = 2, WMD = 0.93 mm, 95% CI [−0.69; 2.55], p = .26), even if with substantial heterogeneity. CONCLUSIONS: No single decontamination method demonstrated clear evidence of superiority compared to the others. Systemic antibiotics, but not Er:Yag laser, may provide short‐term clinical benefits in terms of treatment success (CRD42020182303)

    Epithelial V-like Antigen (EVA), a Novel Member of the Immunoglobulin Superfamily, Expressed in Embryonic Epithelia with a Potential Role as Homotypic Adhesion Molecule in Thymus Histogenesis

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    Thymus development depends on a complex series of interactions between thymocytes and the stromal component of the organ. To identify regulated genes during this codependent developmental relationship, we have applied an RNA fingerprinting technique to the analysis of thymus expansion and maturation induced in recombinase-deficient mice injected with anti-CD3 antibodies. This approach led us to the identification of a gene encoding a new member of the immunoglobulin superfamily, named epithelial V-like antigen (EVA), which is expressed in thymus epithelium and strongly downregulated by thymocyte developmental progression. This gene is expressed in the thymus and in several epithelial structures early in embryogenesis. EVA is highly homologous to the myelin protein zero and, in thymus-derived epithelial cell lines, is poorly soluble in nonionic detergents, strongly suggesting an association to the cytoskeleton. Its capacity to mediate cell adhesion through a homophilic interaction and its selective regulation by T cell maturation might imply the participation of EVA in the earliest phases of thymus organogenesis
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