Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.0305
F. Azevedo, L. Esteva, C. Ferreira
A mathematical model considering female and male individuals is proposed to evaluate vaccination strategies applied to control of HPV transmission in human population. The basic reproductive number of the disease, $R_0$, is given by the geometric mean of the basic reproductive number of female and male populations. The model has a globally asymptotically stable disease-free equilibrium whenever $R_0 <1$. Furthermore, it has an unique endemic state when $R_0$ exceeds unity which is globally asymptotically stable. Numerical simulations were done to compare several different vaccination schedules. The results showed that the vaccination strategies that do not include vaccination of men can only control the disease if more than 90% of women are vaccinated. The sensitivity analysis indicated that the relevant parameters to control HPV transmission, in order of importance, are vaccine efficacy times the fraction of population that is vaccinated, disease recovery-rate, and disease transmission rate. Therefore, health politics that promoting the increase of vaccine coverage, and screening for the disease in both population can improve disease control.
{"title":"Assessing the Impact of Prophylactic Vaccines on HPV Prevalence","authors":"F. Azevedo, L. Esteva, C. Ferreira","doi":"10.5540/TEMA.2019.020.02.0305","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.0305","url":null,"abstract":"A mathematical model considering female and male individuals is proposed to evaluate vaccination strategies applied to control of HPV transmission in human population. The basic reproductive number of the disease, $R_0$, is given by the geometric mean of the basic reproductive number of female and male populations. The model has a globally asymptotically stable disease-free equilibrium whenever $R_0 <1$. Furthermore, it has an unique endemic state when $R_0$ exceeds unity which is globally asymptotically stable. Numerical simulations were done to compare several different vaccination schedules. The results showed that the vaccination strategies that do not include vaccination of men can only control the disease if more than 90% of women are vaccinated. The sensitivity analysis indicated that the relevant parameters to control HPV transmission, in order of importance, are vaccine efficacy times the fraction of population that is vaccinated, disease recovery-rate, and disease transmission rate. Therefore, health politics that promoting the increase of vaccine coverage, and screening for the disease in both population can improve disease control.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130519707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.0381
M. Curi, Vanessa Vitoriano da Silva, Vanessa Vitoriano da Silva
This paper describes the steps to convert a paper-and-pencil English proficiency test for academic purposes, consisting of multiple choice items administered following the Admissible Probability Measurement Procedure [24], adopted by the graduate program at the Institute of Mathematics and Computer Sciences at the University of São Paulo (ICMC-USP), Brazil, to a computerized adaptive test (CAT) based on an Item Response Theory Model (IRT). Despite the fact that the program accepts various internationally recognized tests that attest non-native speakers English proficiency, such as the Test of English as a Foreign Language (TOEFL), the International English Language Testing System (IELTS) and the Cambridge English: Proficiency (CPE), for instance, its requirement is incoherent in public universities in Brazil due to the cost, which ranges from US$ 200.00 to US$ 300.00 per exam. The TAI-PI software (Computerized Adaptive Test for English Proficiency), which was developed in Java language and SQLite, started to be used to assess the English pro?ciency of students on the program from October, 2013. The statistical methodology used was defined considering the history and aims of the test and adopted Samejima's Graded Response Model [21], the Kullback-Leibler information criterion for item selection, the a posteriori estimation method for latent trait [2] and the Shadow Test approach [29] to impose restrictions (content and test length) on the test composition of each individual. A description of the test design, the statistical methods used, and the results of a real application of TAI-PI for graduate students are presented in this paper, as well as the validation studies of the new methodology for pass or fail classification, showing the good quality of the new evaluation system and examination of improvement using the IRT and CAT methods.
{"title":"Academic English Proficiency Assessment Using a Computerized Adaptive Test","authors":"M. Curi, Vanessa Vitoriano da Silva, Vanessa Vitoriano da Silva","doi":"10.5540/TEMA.2019.020.02.0381","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.0381","url":null,"abstract":"This paper describes the steps to convert a paper-and-pencil English proficiency test for academic purposes, consisting of multiple choice items administered following the Admissible Probability Measurement Procedure [24], adopted by the graduate program at the Institute of Mathematics and Computer Sciences at the University of São Paulo (ICMC-USP), Brazil, to a computerized adaptive test (CAT) based on an Item Response Theory Model (IRT). Despite the fact that the program accepts various internationally recognized tests that attest non-native speakers English proficiency, such as the Test of English as a Foreign Language (TOEFL), the International English Language Testing System (IELTS) and the Cambridge English: Proficiency (CPE), for instance, its requirement is incoherent in public universities in Brazil due to the cost, which ranges from US$ 200.00 to US$ 300.00 per exam. The TAI-PI software (Computerized Adaptive Test for English Proficiency), which was developed in Java language and SQLite, started to be used to assess the English pro?ciency of students on the program from October, 2013. The statistical methodology used was defined considering the history and aims of the test and adopted Samejima's Graded Response Model [21], the Kullback-Leibler information criterion for item selection, the a posteriori estimation method for latent trait [2] and the Shadow Test approach [29] to impose restrictions (content and test length) on the test composition of each individual. A description of the test design, the statistical methods used, and the results of a real application of TAI-PI for graduate students are presented in this paper, as well as the validation studies of the new methodology for pass or fail classification, showing the good quality of the new evaluation system and examination of improvement using the IRT and CAT methods.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125501591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.0257
Marcos Vinícius Bião Cerqueira, D. G. Costa
As redes de sensores sem fio alcancaram um papel de destaque no cenario atual das novas de tecnologias de comunicacao, centradas em aplicacoes de Internet das Coisas e Cidades Inteligentes, sobretudo quando câmeras sao utilizadas para obter dados visuais do ambiente monitorado. Nessas redes, questoes de eficiencia energetica sao centrais, uma vez que, frequentemente, sensores sao alimentados por bateria. Para tanto, um correto e eficiente planejamento energetico de redes de sensores sem fio e fundamental para diversas aplicacoes, levando a escolha mais apropriada dos sensores, dos protocolos de comunicacao e das unidades de monitoramento. Visando dar suporte a estimativas de desempenho de redes de sensores visuais sem fio, permitindo analises teoricas sem necessitar da implantacao fisica das redes, este artigo propoe um novo modelo matematico para estimativas de consumo de energia de sensores equipados com câmeras, permitindo importantes avaliacoes de desempenho antes da implantacao da rede real. Alem do modelo e apresentada uma nova ferramenta computacional, EnergyWVSN, desenvolvida para facilitar o uso pratico do modelo proposto.
{"title":"Um Modelo Matemático para Estimativas do Consumo de Energia em Redes de Sensores Visuais sem Fio","authors":"Marcos Vinícius Bião Cerqueira, D. G. Costa","doi":"10.5540/TEMA.2019.020.02.0257","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.0257","url":null,"abstract":"As redes de sensores sem fio alcancaram um papel de destaque no cenario atual das novas de tecnologias de comunicacao, centradas em aplicacoes de Internet das Coisas e Cidades Inteligentes, sobretudo quando câmeras sao utilizadas para obter dados visuais do ambiente monitorado. Nessas redes, questoes de eficiencia energetica sao centrais, uma vez que, frequentemente, sensores sao alimentados por bateria. Para tanto, um correto e eficiente planejamento energetico de redes de sensores sem fio e fundamental para diversas aplicacoes, levando a escolha mais apropriada dos sensores, dos protocolos de comunicacao e das unidades de monitoramento. Visando dar suporte a estimativas de desempenho de redes de sensores visuais sem fio, permitindo analises teoricas sem necessitar da implantacao fisica das redes, este artigo propoe um novo modelo matematico para estimativas de consumo de energia de sensores equipados com câmeras, permitindo importantes avaliacoes de desempenho antes da implantacao da rede real. Alem do modelo e apresentada uma nova ferramenta computacional, EnergyWVSN, desenvolvida para facilitar o uso pratico do modelo proposto.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114309572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.0229
Robson Mariano Oliveira Silva, M. Leal, F. M. Lima
O uso de modelos para diagnostico auxiliado por computador (CAD) tem sido proposto para auxiliar na deteccao e classificacao do câncer de mama. Neste trabalho, avaliou-se o desempenho dos modelos de rede neural de perceptrons de multiplas camadas e maquina de vetores de suporte nao linear, para classificar nodulos de câncer de mama. Dez caracteristicas morfologicas, do contorno de 569 amostras, foram usadas como entrada nos classificadores. Os melhores resultados obtidos para a acuracia e taxa de falso negativo no modelo de maquina de vetor de suporte nao linear foram 98,58% e 1,96%, respectivamente. O modelo de rede neural apresentou desempenho inferior ao classificador de maquina de vetor de suporte nao linear. Os resultados medios obtidos, com a aplicacao dos modelos propostos, mostram-se promissores, na classificacao do câncer de mama.
{"title":"Predição do Câncer de Mama com Aplicação de Modelos de Inteligência Computacional","authors":"Robson Mariano Oliveira Silva, M. Leal, F. M. Lima","doi":"10.5540/TEMA.2019.020.02.0229","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.0229","url":null,"abstract":"O uso de modelos para diagnostico auxiliado por computador (CAD) tem sido proposto para auxiliar na deteccao e classificacao do câncer de mama. Neste trabalho, avaliou-se o desempenho dos modelos de rede neural de perceptrons de multiplas camadas e maquina de vetores de suporte nao linear, para classificar nodulos de câncer de mama. Dez caracteristicas morfologicas, do contorno de 569 amostras, foram usadas como entrada nos classificadores. Os melhores resultados obtidos para a acuracia e taxa de falso negativo no modelo de maquina de vetor de suporte nao linear foram 98,58% e 1,96%, respectivamente. O modelo de rede neural apresentou desempenho inferior ao classificador de maquina de vetor de suporte nao linear. Os resultados medios obtidos, com a aplicacao dos modelos propostos, mostram-se promissores, na classificacao do câncer de mama.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121029664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.359
Manolo Rodriguez Heredia, Cecilia Orellana Castro, A. Oliveira
This study aims to improve the computation of the search direction in the primal-dual Interior Point Method through preconditioned iterative methods. It is about a hybrid approach that combines the Controlled Cholesky Factorization preconditioner and the Splitting preconditioner. This approach has shown good results, however, in these preconditioners there are factors that reduce their efficiency, such as faults on the diagonal when performing the Cholesky factorization, as well as a demand for excessive memory, among others. Thus, some modifications are proposed in these preconditioners, as well as a new phase change, in order toimprove the performance of the hybrid preconditioner. In the Controlled Cholesky Factorization, the parameters that control the filling and the correction of the faults which occur on the diagonal are modified. It considers the relationship between the components from Controlled Cholesky Factorization obtained before and after the fault on the diagonal. In the Splitting preconditioner, in turn, a sparse base is constructed through an appropriate ordering of the columns from constrained matrix optimization problem. In addition, a theoretical result is presented, which shows that, with the proposed ordering, the condition number of the preconditioned Normal Equation matrix with the Splitting preconditioner is uniformly limited by an amount that depends only on the original data of the problem and not on the iteration of the Interior Point Method. Numerical experiments with large scale problems, corroborate the robustness and computational efficiency from this approach.
{"title":"A New Hybrid Preconditioner for the Interior Point Method","authors":"Manolo Rodriguez Heredia, Cecilia Orellana Castro, A. Oliveira","doi":"10.5540/TEMA.2019.020.02.359","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.359","url":null,"abstract":"This study aims to improve the computation of the search direction in the primal-dual Interior Point Method through preconditioned iterative methods. It is about a hybrid approach that combines the Controlled Cholesky Factorization preconditioner and the Splitting preconditioner. This approach has shown good results, however, in these preconditioners there are factors that reduce their efficiency, such as faults on the diagonal when performing the Cholesky factorization, as well as a demand for excessive memory, among others. Thus, some modifications are proposed in these preconditioners, as well as a new phase change, in order toimprove the performance of the hybrid preconditioner. In the Controlled Cholesky Factorization, the parameters that control the filling and the correction of the faults which occur on the diagonal are modified. It considers the relationship between the components from Controlled Cholesky Factorization obtained before and after the fault on the diagonal. In the Splitting preconditioner, in turn, a sparse base is constructed through an appropriate ordering of the columns from constrained matrix optimization problem. In addition, a theoretical result is presented, which shows that, with the proposed ordering, the condition number of the preconditioned Normal Equation matrix with the Splitting preconditioner is uniformly limited by an amount that depends only on the original data of the problem and not on the iteration of the Interior Point Method. Numerical experiments with large scale problems, corroborate the robustness and computational efficiency from this approach.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"97 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130390201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.331
Wesley de Oliveira Barbosa, A. W. Vieira
The automatic detection of lines and curves from color images is a very important task in many applications, such as object recognition and scene reconstruction. Although there are closed formulation for curve fitting to a set of points, if the point set describes more than one instance of the object, as two circles for example, there is no closed formulation for obtaining the individual set of parameters without a priori information of which points belong to each object. However, it is usual the presence of multiple instances of objects such as lines and circles on an image. The well known Hough Transform is an efficient tool for recovering multiple objects from images using a voting process where the usual presence of false positives is an issue. In our work, we present an improvement on the voting process to detect multiple circles using Hough Transform in order to avoid false positives. Our experiments show that our voting process leads to a more robust detection, reducing the number of false positive and providing a more accurate detection even with large number of circles.
{"title":"On the Improvement of Multiple Circles Detection from Images Using Hough Transform","authors":"Wesley de Oliveira Barbosa, A. W. Vieira","doi":"10.5540/TEMA.2019.020.02.331","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.331","url":null,"abstract":"The automatic detection of lines and curves from color images is a very important task in many applications, such as object recognition and scene reconstruction. Although there are closed formulation for curve fitting to a set of points, if the point set describes more than one instance of the object, as two circles for example, there is no closed formulation for obtaining the individual set of parameters without a priori information of which points belong to each object. However, it is usual the presence of multiple instances of objects such as lines and circles on an image. The well known Hough Transform is an efficient tool for recovering multiple objects from images using a voting process where the usual presence of false positives is an issue. In our work, we present an improvement on the voting process to detect multiple circles using Hough Transform in order to avoid false positives. Our experiments show that our voting process leads to a more robust detection, reducing the number of false positive and providing a more accurate detection even with large number of circles.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"243 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120934134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.0343
Wesley Felipe Ferreira Mora Gil, T. Carvalho, P. Mancera, D. S. Rodrigues
The incidence of neoplastic diseases shows that the search for more effective cancer treatments is still necessary. In addition to standard treatments such as chemo- and radiotherapy, new treatment modalities have been focused in recent advances in immunology. Since little has been discussed about the biological implications of chemotherapy with respect to its impact on the immune system and on the other normal, ``healthy'' cells, we devote the present mathematical modeling work to do so. First, we prove the invariance of the region where all state variables remain positive (i.e., the number of cancer cells, normal cells and immune cells, and the amount of chemotherapy); afterwards, we analyze the model in terms of the linear stability of the system, and we establish a necessary and sufficient condition for the local stability of the {it{cure}} equilibrium point. Moreover, we simulate some scenarios involving both the immune system and chemotherapy, showing that a reasonable treatment strategy occurs when these are combined suitably.
{"title":"A Mathematical Model on the Immune System Role in Achieving Better Outcomes of Cancer Chemotherapy","authors":"Wesley Felipe Ferreira Mora Gil, T. Carvalho, P. Mancera, D. S. Rodrigues","doi":"10.5540/TEMA.2019.020.02.0343","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.0343","url":null,"abstract":"The incidence of neoplastic diseases shows that the search for more effective cancer treatments is still necessary. In addition to standard treatments such as chemo- and radiotherapy, new treatment modalities have been focused in recent advances in immunology. Since little has been discussed about the biological implications of chemotherapy with respect to its impact on the immune system and on the other normal, ``healthy'' cells, we devote the present mathematical modeling work to do so. First, we prove the invariance of the region where all state variables remain positive (i.e., the number of cancer cells, normal cells and immune cells, and the amount of chemotherapy); afterwards, we analyze the model in terms of the linear stability of the system, and we establish a necessary and sufficient condition for the local stability of the {it{cure}} equilibrium point. Moreover, we simulate some scenarios involving both the immune system and chemotherapy, showing that a reasonable treatment strategy occurs when these are combined suitably.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125403527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.217
E. C. Grigoletto, E. C. Oliveira, R. F. Camargo
The Mittag-Leffler functions appear in many problems associated with fractional calculus. In this paper, we use the methodology for evaluation of the inverse Laplace transform, proposed by M. N. Berberan-Santos, to show that the three-parameter Mittag-Leffler function has similar integral representations on the positive real axis. Some of the integrals are also presented.
Mittag-Leffler函数出现在许多与分数阶微积分相关的问题中。在本文中，我们使用M. N. Berberan-Santos提出的求拉普拉斯逆变换的方法来证明三参数Mittag-Leffler函数在正实轴上具有相似的积分表示。文中也给出了一些积分。
{"title":"Integral representations of Mittag-Leffler function on the positive real axis","authors":"E. C. Grigoletto, E. C. Oliveira, R. F. Camargo","doi":"10.5540/TEMA.2019.020.02.217","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.217","url":null,"abstract":"The Mittag-Leffler functions appear in many problems associated with fractional calculus. In this paper, we use the methodology for evaluation of the inverse Laplace transform, proposed by M. N. Berberan-Santos, to show that the three-parameter Mittag-Leffler function has similar integral representations on the positive real axis. Some of the integrals are also presented.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127803118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.295
Luiz Otávio R. A. Sereno, J. L. Acebal
Among many structures in the cells of living beings, there are proteins called transcription factors (TF) that are responsible to inhibit or promote the transcription of the DNA. To accomplish their function, the transcription factors perform aleatory searches around the cytoplasm (for prokaryotic cells) and along the DNA chain as well for specific targets located in the DNA. Its movement fits into the class of anomalous Brownian. The efficiency in TFs search has implications in the cellular copy and in protection against viruses, hence the knowledge of the mechanism is of great interest. In the present work, we study the searching process of the TFs by simulating the anomalous Brownian motion through the cytoplasm and DNA chain by means of Levy flights through a lattice model and through a free grid model. The final distribution of positions of the TF are obtained. The search efficiency is investigated in terms of the model parameters.
{"title":"Target Search for Transcription Factors on DNA Chains","authors":"Luiz Otávio R. A. Sereno, J. L. Acebal","doi":"10.5540/TEMA.2019.020.02.295","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.295","url":null,"abstract":"Among many structures in the cells of living beings, there are proteins called transcription factors (TF) that are responsible to inhibit or promote the transcription of the DNA. To accomplish their function, the transcription factors perform aleatory searches around the cytoplasm (for prokaryotic cells) and along the DNA chain as well for specific targets located in the DNA. Its movement fits into the class of anomalous Brownian. The efficiency in TFs search has implications in the cellular copy and in protection against viruses, hence the knowledge of the mechanism is of great interest. In the present work, we study the searching process of the TFs by simulating the anomalous Brownian motion through the cytoplasm and DNA chain by means of Levy flights through a lattice model and through a free grid model. The final distribution of positions of the TF are obtained. The search efficiency is investigated in terms of the model parameters.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126109396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-29DOI: 10.5540/TEMA.2019.020.02.323
L. Markenzon, C. F. E. M. Waga
Block graphs has been extensively studied for many decades. In this paper we present a new characterization of the class in terms of one-vertex extensions. To this purpose, a specific representation based on the concept of boundary cliques is presented, bringing about some properties of the graph.
{"title":"Characterizing Block Graphs in Terms of One-vertex Extensions","authors":"L. Markenzon, C. F. E. M. Waga","doi":"10.5540/TEMA.2019.020.02.323","DOIUrl":"https://doi.org/10.5540/TEMA.2019.020.02.323","url":null,"abstract":"Block graphs has been extensively studied for many decades. In this paper we present a new characterization of the class in terms of one-vertex extensions. To this purpose, a specific representation based on the concept of boundary cliques is presented, bringing about some properties of the graph.","PeriodicalId":163536,"journal":{"name":"TEMA - Tendências em Matemática Aplicada e Computacional","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114765399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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