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关键词： Frobenius extriangulated categories   2-Calabi-Yau extriangulated (or triangulated) categories   Cotorsion pairs   Cluster algebras  

摘要： Nakaoka and Palu introduced the notion of extriangulated categories by extracting the similarities between exact categories and triangulated categories. In this paper, we study cotorsion pairs in a Frobenius extriangulated category C. Especially, for a 2-Calabi-Yau extriangulated category C with a cluster structure, we describe the cluster substructure in the cotorsion pairs. For rooted cluster algebras arising from C with cluster tilting objects, we give a one-to-one correspondence between cotorsion pairs in C and certain pairs of their rooted cluster subalgebras which we call complete pairs. Finally, we explain this correspondence by an example relating to a Grassmannian cluster algebra.

关键词： Altmetrics   Mendeley   Egyptian research   Research impact   Readership analysis  

摘要： Mendeley is a social network that allows researchers worldwide to discover, search and share resources and to cooperate with peer researchers. We can recognize a large amount of exhaustive information about who reads research articles and the contexts in which research articles are read by using data about people who register in Mendeley as readers of articles. The purpose of this paper is to explore different types of users of international Egyptian academic articles indexed in Scopus across four major fields: health sciences, life sciences, physical sciences and social sciences inside and outside academia. The aim is to determine the impact and use of international Egyptian academic articles in Mendeley compared to their citation impact and to explore whether there is any correlation between Mendeley readership counts and the citation indicators for these publications. Furthermore, this study analyses readers' categories and discovers their country locations according to the data retrieved from Mendeley profiles. The data for this study are collected from the Scopus database. Webometric Analyst 2.0 is used to retrieve Mendeley readership statistics for all collected articles. This information will help in understanding how and to what extent Mendeley readership metrics are applicable in assessing the publications of Egyptian authors and in understanding the usage versus citation pattern and impact of Egyptian scientific outputs on global society. The results indicate that the majority of readers in all disciplines are Ph.D. students, master's students, and post-graduate students;however, other types of academics are also represented. The findings also indicate that the highest correlations between citations and Mendeley readership counts are found for the types of users who frequently author academic papers, except for professors in some sub-disciplines. Regarding country locations, Egyptian international publications are mostly used by users from more than 100 co

关键词： Policy-specific uncertainty   Cross-category spillovers   Variance decomposition  

摘要： This paper examine cross-category spillovers of policy-specific uncertainty in China. We find that monetary policy and exchange rate policy are net givers, while fiscal policy and trade policy are net receivers. Monetary policy plays the dominant role. Spillovers are countercyclical. (C) 2019 Elsevier B.V. All rights reserved.

关键词： bootstrap   decision trees   personalized medicine   random forest   subgroup discovery  

摘要： Personalized medicine aims at identifying best treatments for a patient with given characteristics. It has been shown in the literature that these methods can lead to great improvements in medicine compared to traditional methods prescribing the same treatment to all patients. Subgroup identification is a branch of personalized medicine, which aims at finding subgroups of the patients with similar characteristics for which some of the investigated treatments have a better effect than the other treatments. A number of approaches based on decision trees have been proposed to identify such subgroups, but most of them focus on two-arm trials (control/treatment) while a few methods consider quantitative treatments (defined by the dose). However, no subgroup identification method exists that can predict the best treatments in a scenario with a categorical set of treatments. We propose a novel method for subgroup identification in categorical treatment scenarios. This method outputs a decision tree showing the probabilities of a given treatment being the best for a given group of patients as well as labels showing the possible best treatments. The method is implemented in an R package psica available on CRAN. In addition to a simulation study, we present an analysis of a community-based nutrition intervention trial that justifies the validity of our method.

关键词： Body composition   Anthropometry accelerometer   Movement monitor   Measurement  

摘要： ObjectivesTo investigate the relationship between longitudinal weight-change and objectively-measured physical activity (PA) in a rural African setting in 143 adults (>= 30years), using data from two cross-sectional surveys, separated by approximately 10years. Participants were categorised into three weight-change groups (Weight-loss:>= 25kgm(-2)-><25kgm(-2);Weight-gain:<25kgm(-2)->>= 25kgm(-2);Weight-stability: remained<25kgm(-2) or >= 25kgm(-2)). Daily ambulation and activity energy expenditure (AEE), measured in the 2005-2007 health survey, was examined across the weight-change groups. Using the daily AEE data, the proportion of those in the weight-change groups, meeting or not meeting two PA guidelines (150- and 420minweek(-1)), was ***-change was found in 18.2% of the sample. There was no significant overall body mass change (+1.2kg, p=0.1616). However, there was significant change in body mass in the weight-gain (+15.2kg) and weight-loss (-10.8kg) groups (p <= 0.0011). Nearly 90% of those who gained weight met the 150minweek(-1) guideline. A significantly greater proportion of the weight-stable group (<25kgm(-2)) met the 420minweek(-1) guideline (p<0.05). Ambulatory level was high irrespective of weight group, although the weight-stable group (<25kgm(-2)) approached 15,000stepsday(-1). There was an inconsistent and weak association between PA and weight-change in this group.

关键词： HIV infection   Latent reservoirs   Global stability   Lyapunov function   discrete time models  

摘要： This paper studies the global stability of two discrete-time HIV infection models. The models integrate (i) latently infected cells, (ii) long-lived chronically infected cells and (iii) short-lived infected cells. The second model generalizes the first one by assuming that the incidence rate of infection as well as the production and removal rates of the HIV particles and cells are modeled by general nonlinear functions. We discretize the continuous-time models by using a nonstandard finite difference scheme. The positivity and boundedness of solutions are established. The basic reproduction number is derived. By using the Lyapunov method, we prove the global stability of the models. Numerical simulations are presented to illustrate our theoretical results.

关键词： Atypia of undetermined significance   Bethesda system   follicular lesion of undetermined significance  

摘要： Background:Thyroid gland nodules are common and fine-needle aspiration (FNA) is the gold standard for screening those *** Bethesda system for reporting thyroid cytolopathology standardized reporting thyroid nodules aspirations, but atypia of undetermined significance or follicular lesion of undetermined significance (Bethesda category III) was the most controversial *** aim of our study is to review our institutional experience and analyze the clinical implications of making a diagnosis of AUS/FLUS (Bethesda category III). Methods: This is a retrospective study of an 889 thyroid FNAs from 825 patients in Salmaniya Medical Complex, during (January 2013-December 2017). Results:The most common cause for designating cases as AUS/FLUS (Bethesda category III) was the presence of features suggestive of papillary thyroid carcinoma, but not quite fulfilling the criteria for such diagnosis. Ninety-six cases were diagnosed asAUS/FLUS (10.7%),in which 26 (27%) patients underwent surgery without repeating the FNA,25 (26%) underwent a second FNA and 43 (44.7%) patients were followed up by ultrasound. On repeating the FNA, 1 (4%) was unsatisfactory, 13 (52%) were benign, 10 (40%) were AUS/FLUS, and only 1 (4%) was categorized as *** cases were surgically excised, in which 4 (13.3%) were diagnosed as follicular adenoma, 2 (6.6%) as Hurthle cell adenoma, 9 (30%) as multinodular goiter, 5 (16.6%) as multinodular goiter with Hashimoto thyroiditis, 1 (3.3%) as colloid nodule with Hashimoto thyroiditis, and 9 (30%) as papillary thyroid *** all the cases diagnosed initially as AUS/FLUS (Bethesda category III), 9 (9.3%) cases were diagnosed as papillary thyroid carcinoma. Conclusion: Diagnostically, we almost meet the international standards of designating cases with AUS/FLUS (Bethesda category III) and approximate the risk of malignancy. However, the clinical management's guidelines should be followed to decrease the risk of unnecessary surgeries

关键词： Group action   Equivariantization   Triangulated category   Weighted projective line  

摘要： In this article, we investigate the category A(G) of equivariant objects of an additive category A with respect to an action of a finite group G. We show that if G is solvable then we can reconstruct A from A(G) via a finite sequence of equivariantizations. We also consider the possibility of a triangulated structure on A(G) canonical in certain sense when A is triangulated and give several instances in which A(G) is indeed canonically triangulated. (C) 2019 Elsevier Inc. All rights reserved.

关键词： Relative category   Sectional category   Lusternik-Schnirelmann category   Topological complexity  

摘要： We give a characterization of relative category in the sense of Doeraene-El Haouari by using open covers. We also prove that relative category and sectional category can be defined by taking arbitrary covers (not necessarily open) when dealing with ANR spaces. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Fell hypograph topology   Compact-open topology   Moving off property   Baire space   Meager space  

摘要： For a Tychonoff space X and a subspace Y subset of R, we study Baire category properties of the space C-down arrow F(X, Y) of continuous functions from X to Y, endowed with the Fell hypograph topology. We characterize pairs X, Y for which the function space C down arrow F(X, Y) is oo-meager, meager, Baire, Choquet, strong Choquet, (almost) complete-metrizable or (almost) Polish. (C) 2019 Elsevier B.V. All rights reserved.