Filomat最新文献

{"title":"Alcohol consumption among adolescents during the COVID-19 pandemic, ConVid Adolescents - Behavior Research.","authors":"Deborah Carvalho Malta, Crizian Saar Gomes, Nádia Machado de Vasconcelos, Marilisa Berti de Azevedo Barros, Margareth Guimarães Lima, Paulo Roberto Borges de Souza Júnior, Celia Landmann Szwarcwald","doi":"10.1590/1980-549720230007.supl.1","DOIUrl":"10.1590/1980-549720230007.supl.1","url":null,"abstract":"<p><strong>Objective: </strong>To describe the prevalence of alcohol consumption before and during the COVID-19 pandemic and to analyze the factors associated with this behavior during the period of social distancing among Brazilian adolescents.</p><p><strong>Methods: </strong>Cross-sectional study using data from the ConVid Adolescents survey, carried out via the Internet between June and September 2020. The prevalence of alcohol consumption before and during the pandemic, as well as association with sociodemographic variables, mental health, and lifestyle were estimated. A logistic regression model was used to assess associated factors.</p><p><strong>Results: </strong>9,470 adolescents were evaluated. Alcohol consumption decreased from 17.70% (95%CI 16.64-18.85) before the pandemic to 12.80% (95%CI 11.85-13.76) during the pandemic. Alcohol consumption was associated with the age group of 16 and 17 years (OR=2.9; 95%CI 1.08-1.53), place of residence in the South (OR=1.82; 95%CI 1.46-2.27) and Southeast regions (OR=1.33; 95%CI 1.05-1.69), having three or more close friends (OR=1.78; 95%CI 1.25-2.53), reporting worsening sleep problems during the pandemic (OR=1.59; 95%CI 1.20-2.11), feeling sad sometimes (OR=1,83; 95%CI 1,40-2,38) and always (OR=2.27; 95%CI 1.70-3.05), feeling always irritated (OR=1,60; 95%CI 1,14-2,25), being a smoker (OR=13,74; 95%CI 8.63-21.87) and a passive smoker (OR=1.76; 95%CI 1.42-2.19). Strict adherence to social distancing was associated with lower alcohol consumption (OR=0.40; 95%CI 0.32-0.49).</p><p><strong>Conclusions: </strong>The COVID-19 pandemic led to a decrease in consumption of alcoholic beverages by Brazilian adolescents, which was influenced by sociodemographic and mental health factors, adherence to social restriction measures and lifestyle in this period. Managers, educators, family and the society must be involved in the articulation of Public Policies to prevent alcohol consumption.</p>","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"1 1","pages":"e230007"},"PeriodicalIF":0.0,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90245264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stability analysis for pricing options via time fractional Heston model","authors":"Hassen Arfaoui, Mohamed Kharrat","doi":"10.2298/fil2309685a","DOIUrl":"https://doi.org/10.2298/fil2309685a","url":null,"abstract":"In this work, we have studied the time fractional-order derivative of the pricing European options under Heston model. We found some positivity conditions for the solution obtained relative to the numerical methods used. Also, thanks to the properties of the Mittag-Leffler function, we were able to establish a stability result of the solution. Some numerical experiments are carried out to confirm the theoretical results obtained.","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135594170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On a classification of faithful representations of the Galilean lie algebra on the polynomial ring in three variables","authors":"Liang Wu, Youjun Tan","doi":"10.2298/fil2309807w","DOIUrl":"https://doi.org/10.2298/fil2309807w","url":null,"abstract":"We show a complete classification of faithful representations of the 2 + 1 space-times Galilean Lie algebra on the polynomial ring in three variables, where actions of the Galilean Lie algebra are given by derivations with coefficients of degree at most one. In particular, all such representations of the Galilean Lie algebra are explicitly constructed and classified by one parameter. In a more general setting we show that, with respect to a nonzero abelian ideal of a finite-dimensional Lie algebra, there is at most one such representation up to graded-equivalence.","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135594176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The spinor representations of framed Bertrand curves","authors":"Zehra İşbilir, Bahar Yazıcı, Murat Tosun","doi":"10.2298/fil2309831i","DOIUrl":"https://doi.org/10.2298/fil2309831i","url":null,"abstract":"In this study, we intend to examine the framed Bertrand curves in three-dimensional Euclidean space E3 by using the spinors, which have a fundamental place and importance in different disciplines from mathematics to physics. For this purpose, we investigate the spinor representations of framed Bertrand mates in E3. Additionally, we present some geometric results and interpretations. Then, we construct numerical examples with illustrative figures in order to support the given materials.","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135594435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mappings preserving sum of products α1ab* + α2b*a + α3ba* (resp., Α1ab* + α2b*a + α3a*b) on *-algebras","authors":"Ali Taghavi, Motta da, Maria Marietto","doi":"10.2298/fil2309799t","DOIUrl":"https://doi.org/10.2298/fil2309799t","url":null,"abstract":"Let A and B be two unital prime complex *-algebras such that A has a nontrivial projection. In this paper, we study the structure of the bijective mappings ? ? A ? B preserving sum of products ?1ab* + ?2b*a + ?3ba* (resp., ?1ab* + ?2b*a + ?3a*b), where the scalars {?k}3k =1 are rational numbers satisfying some conditions.","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135595950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Existence and stability results for a coupled system of Hilfer fractional Langevin equation with non local integral boundary value conditions","authors":"Khalid Hilal, Ahmed Kajouni, Hamid Lmou","doi":"10.2298/fil2304241h","DOIUrl":"https://doi.org/10.2298/fil2304241h","url":null,"abstract":"This paper deals with the existence and uniqueness of solution for a coupled system of Hilfer fractional Langevin equation with non local integral boundary value conditions. The novelty of this work is that it is more general than the works based on the derivative of Caputo and Riemann-Liouville, because when ? = 0 we find the Riemann-Liouville fractional derivative and when ? = 1 we find the Caputo fractional derivative. Initially, we give some definitions and notions that will be used throughout the work, after that we will establish the existence and uniqueness results by employing the fixed point theorems. Finaly, we investigate different kinds of stability such as Ulam-Hyers stability, generalized Ulam-Hyers stability.","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135686288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Jordan *-derivations on standard operator algebras","authors":"A. Ansari, F. Shujat","doi":"10.2298/fil2301037a","DOIUrl":"https://doi.org/10.2298/fil2301037a","url":null,"abstract":"LetH be a real or complex Hilbert space with dim(H) > 1, B(H) be algebra of all bounded linear operators on H and A(H) ? B(H) be a standard operator algebra on H. If D : A(H) ? B(H) is a linear mapping satisfying D(An+1) = Pn i=0 AiD(A)(A*)n?i for all A ? A(H), then D is a Jordan *-derivation on A(H). Later, we discuss some algebraic identities on semiprime rings.","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68266084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abundant semigroups with weakly simplistic RGQA transversals","authors":"Pei Wang, Xiangjun Kong","doi":"10.2298/fil2301155w","DOIUrl":"https://doi.org/10.2298/fil2301155w","url":null,"abstract":"As the real common generalisations of both orthodox transversals and adequate transversals in abundant semigroups, the concept of refined generalised quasi-adequate transversals, briefly, RGQA transversals was introduced by Kong and Wang. In this paper, for the RGQA transversal, the necessary and sufficient condition for the sets I and ? to be bands is investigated. It is demonstrated that the sets I and ? are both bands if and only if the RGQA transversal is weakly simplistic. Moreover, the RGQA transversal So being weakly simplistic is different from So being a quasi-ideal nor the abundant semigroup S satisfying the regularity condition. Finally, by means of a quasi-adequate semigroup and a band, the structure theorem for an abundant semigroup with a weakly simplistic RGQA transversal is established.","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68266534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Representation of essentially semi regular linear relations and perturbations","authors":"Sonia Keskes, M. Mnif","doi":"10.2298/fil2302443k","DOIUrl":"https://doi.org/10.2298/fil2302443k","url":null,"abstract":"In the case of linear operator the property P(B, k) was introduced by M.A. Kaashoek. In this paper, we characterize the essentially semi regular linear relation in terms of the property P(B, k). After that and as an application of this result we give some connection between essentially semi regular and semi regular linear relations. Further, we will give some supplementary conditions on essentially semi regular linear relation to be semi Fredholm. Then, we analyze the stability of the class of essentially semi regular linear relations under small perturbations and Riesz operators. Finally, we study some properties of the essentially semi regular spectrum of a linear relation and we establish a spectral mapping theorem.","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68266972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Confidence ellipses for simple regression parameters with strongly mixing errors","authors":"Abdelkader Elmoumen, Halima Zerouati, A. Dahmani","doi":"10.2298/fil2302591e","DOIUrl":"https://doi.org/10.2298/fil2302591e","url":null,"abstract":"In this work, we establish exponential inequalities which allow us to construct confidence regions, characterized by ellipses, for the least squares estimates of the parameters in the case of a linear regression model with ?-mixing errors.","PeriodicalId":12305,"journal":{"name":"Filomat","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68267274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}