A goodness-of-fit test for the functional linear model with scalar response

In this work, a goodness-of-fit test for the null hypothesis of a functional linear model with scalar response is proposed. The test is based on a generalization to the functional framework of a previous one, designed for the goodness-of-fit of regression models with multivariate covariates using random projections. The test statistic is easy to compute using geometrical and matrix arguments, and simple to calibrate in its distribution by a wild bootstrap on the residuals. The finite sample properties of the test are illustrated by a simulation study for several types of basis and under different alternatives. Finally, the test is applied to two datasets for checking the assumption of the functional linear model and a graphical tool is introduced. Supplementary materials are available online.Comment: Paper: 17 pages, 2 figures, 3 tables. Supplementary material: 8 pages, 6 figures, 10 table

Computer aided volumetric assessment of orbital structures in patients with Graves' orbitopathy: correlation with serum thyroid antiperoxidase antibodies and disease activity

Introduction: Graves' disease is an autoimmune disorder. Goiter and Graves' orbitopathy are frequently seen clinically. It would be helpful for the diagnosis, grading, prognosis, and treatment of this condition if it was possible to find serum biomarkers to establish a connection between the plasma levels of these compounds and orbital changes. Methods: A retrospective study was performed by revising the medical records of 44 patients with Graves' orbitopathy and 15 controls. The Osirix software (Pixmeo, Geneva, Switzerland) was used for manual orbital measurements. Plasma levels of Graves' orbitopathy substances were obtained in the analytical review of the patients. Results: A greater muscle volume was observed in patients with Graves' orbitopathy in relation to the control group (p < 0.001). The clinical activity score (CAS) was associated to total muscle mass (p = 0.013) and retrorbital fat (p = 0.048). Our results indicated a direct relationship between serum concentrations of anti-thyroid peroxidase antibodies and inferior rectus thickening (p = 0.036); however, we did not observe a positive correlation between other muscle volumes and serum concentrations of various thyroid-related substances. Conclusions: This study is the first that uses Osirix measurement software to manually assess orbital features in patients with Graves' orbitopathy. These measurements were compared to the outcomes of tests performed in a laboratory. Among several serum biomarkers, anti-thyroid peroxidase appears to be a reliable biomarker that correlates positively with inferior rectus muscle thickness in patients with thyroid eye disease. This may help to improve the management of this diseaseOpen Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was financially supported by ISCIII (RETICS RD16/0008/0003) and the European Union (European Regional Development Fund—ERDF)S

Functional Classification of Bitcoin Addresses

This paper proposes a classification model for predicting the main activity of bitcoin addresses based on their balances. Since the balances are functions of time, we apply methods from functional data analysis; more specifically, the features of the proposed classification model are the functional principal components of the data. Classifying bitcoin addresses is a relevant problem for two main reasons: to understand the composition of the bitcoin market, and to identify addresses used for illicit activities. Although other bitcoin classifiers have been proposed, they focus primarily on network analysis rather than curve behavior. Our approach, on the other hand, does not require any network information for prediction. Furthermore, functional features have the advantage of being straightforward to build, unlike expert-built features. Results show improvement when combining functional features with scalar features, and similar accuracy for the models using those features separately, which points to the functional model being a good alternative when domain-specific knowledge is not available.Comment: Keywords: Bitcoin market, Darknet market, Functional Data Analysis, Functional Classification, Functional Principal Component

Serum DJ-1/PARK 7 Is a Potential Biomarker of Choroidal Nevi Transformation

PURPOSE. There is substantial evidence that intraocular melanomas arise from benign nevi in the uveal tract. Previous studies performed by the authors revealed that uveal melanoma cells secrete the oncoprotein DJ-1/PARK7 into the extracellular environment and circulation. The aim of this study was to determine whether circulating DJ-1 serum levels correlate with known clinical risk factors of nevi growth. METHODS. Standardized ultrasonography, optical coherence tomography, and eye fundus examinations were used to evaluate the clinical risk factors of nevi growth. These clinical risk factors (including nevi size, distance of margins to the optic disc, detection of acoustic hollowness, presence of ocular symptoms, orange pigment, subretinal fluid, and absence of drusen) were examined in 53 consecutive patients from January 2009 to February 2011. Serum levels of DJ-1/PARK7 in these patients and in healthy age-and sex-matched controls (n ϭ 32) were analyzed using ELISA. RESULTS. Within the choroidal nevi group, DJ-1 serum levels were higher in those with symptoms (P Ͻ 0.033), with a nevus thickness greater than 1.5 mm (P Ͻ 0.001), a large basal diameter greater than 8 mm (P Ͻ 0.001), and the presence of acoustic hollowness (P Ͻ 0.001), compared to those patients without these risk factors. Similar significant differences were found when these at risk nevi subgroups were compared to healthy persons. CONCLUSIONS. Elevated serum levels of DJ-1 are associated with choroidal nevi transformation risk factors. Therefore, DJ-1 appears to be a promising factor for predicting the growth of choroidal nevi and may be a potential biomarker of malignancy. (Invest Ophthalmol Vis Sci. 2012;53:62-67