479 research outputs found
Solution of the Bessel equation via fractional calculus
In this work we discuss the solvability of Bessel's differential equation of order p, which is a particular case of the confluent hypergeometric equation, from the perspective of the theory of calculus of arbitrary order, also usually known as fractional calculus. In particular, in order to compare our method with the formulations in the literature, we raise some questions about interpretations of the Riemann-Liouville operators when acting on certain types of functions. In order to do so, we present the main fractional operators (Riemann-Liouville) as well as the fractional integrodifferential operator, which is a unified view of both integration and differentiation under a single operator. © Sociedade Brasileira de Física.Nesse trabalho estudamos a resolução de um caso particular da equaçãoo hipergeométrica confluente, a equação de Bessel de ordem p, utilizando a teoria do cálculo de ordem não inteira. Em particular, a fim de comparar com a literatura existente, expomos os resultados da nossa investigação sob o rigor do formalismo matemático e levantamos alguns questionamentos a respeito da interpretação dos operadores de Riemann-Liouville quando agindo em certas funções. Para tanto, introduzimos as principais formulações dos operadores fracionários (Riemann-Liouville), assim como o operador de integrodiferenciação fracionária que é a tentativa de se expressar ambos operadores de integração e diferenciação fracionárias de forma unificada373115Oldham, K.B., Spanier, J., (2002) The Fractional Calculus, Theory and Applications of Differentiation and Integration to Arbitrary Order, , (Dover Publications, Inc., New York)de Oliveira, E.C., Tenreiro Machado, J.A., (2014) Math. Prob. EngGarra, R., (2014) Appl. Math. & Comp, 242, p. 576Katugampola, U.N., (2014) A new fractional derivative with classical properties, , ArXiv: 1410.6535v2 [math.CA]Khalil, R., (2014) J. Comput. & Appl. Math, 264, p. 65Ortigueira, M.D., Tenreiro Machado, J.A., (2014) J. Comp. Phys, , http://dx.doi.org/10.1016/j.jcp.2014.07.019Tenreiro Machado, J.A., Galhano, A.M.S.F., Trujillo, J.J., (2014) Scientometrics, 98, p. 577Wang, X., (2014) On the Leibniz rule and fractional derivative for differentiable and nondifferentiable functions, , http://vixra.org/pdf/1404.0072v1.pdf, viXra.org:1404.0072West, B.J., Colloquium: Fractional calculus view of complexity: A tutorial (2014) Rev. Mod. Phys, 8, p. 1169Tenreiro Machado, J.A., Galhano, A.M.S.F., Trujillo, J.J., (2013) Fract. Cal. & App. Anal, 16 (2), p. 479Tarasov, V.E., (2013) Comm. Nonlinear Science and Num. Sim, 18 (11), p. 2945Kobelev, V.V., (2012) On a Leibniz-type fractional derivative, , ArXiv: 1202.2714 [math-ph]Rodrigues, F.G., de Oliveira, E.C., (2015) Introdução ao Cálculo Fracionário, , (a ser submetido para publicação)Gelf'and, I.M., Shilov, G.E., (1964) Generalized Functions, , (Academic Press, Inc., New York)Kilbas, A.A., Srivastava, H.M., Trujillo, J.J., (2006) Theory and Applications of Fractional Differential Equations, , (Elsevier B. V., Amsterdam)Samko, S.G., Kilbas, A.A., Marichev, O.I., (1993) Fractional Integrals and Derivatives, Theory and Applications, , (Gordon and Breach Science Publishers, Amsterdam)Diethelm, K., (2010) The Analysis of Fractional Differential Equations, , (Springer-Verlag, Berlin)Hadamard, J., (1923) Lectures on Cauchy's Problem in Linear Partial Differential Equations, , (Yale Univ. Press, New Haven, (Dover NY, 1952))Elliot, D., (1993) IMA J. Numer. Anal, 13, p. 445Podlubny, I., (1999) Fractional Differential Equations, , (Academic Press, San Diego)Myint-U, T., Debnath, L., (2007) Linear Partial Differential Equations for Scientists and Engineers, , (Birkhäuser Boston)de Oliveira, E.C., Maiorino, J.E., (2010) Introdução aos Métodos da Matemática Aplicada, , (Editora Unicamp, Campinas), 3a: EdiçãoMiller, K.S., Ross, B., (1993) An Introduction to the Fractional Calculus and Fractional Differential Equations, , (John Wiley & Sons, Inc., New York)Tarasov, V.E., (2010) Fractional Dynamics: Applications of Fractional Calculus to Dynamics of Particles, Fields and Media, , (Springer-Verlag, Berlin)Rodrigues, F.G., de Oliveira, E.C., Confluent hypergeometric equation by fractional calculus approach (2015) (aceito para publicação no J. Phys. Math.)Rodrigues, F.G., de Oliveira, E.C., (2015) Introdução às técnicas do cálculo fracionário para estudar modelos da Física-Matemática, , (aceito para publicação na RBEF)In this work we discuss the solvability of Bessel’s differential equation of order p, which is a particular case of the confluent hypergeometric equation, from the perspective of the theory of calculus of arbitrary order, also usually known as fractional calculus. In particular, in order to compare our method with the formulations in the literature, we raise some questions about interpretations of the Riemann-Liouville operators when acting on certain types of functions. In order to do so, we present the main fractional operators (Riemann-Liouville) as well as the fractional integrodifferential operator, which is a unified view of both integration and differentiation under a single operato
Insetos em presépios e as "formigas vestidas" de Jules Martin (1832-1906): uma curiosa manufatura paulistana do final do século XIX
Encontrados no Brasil desde os primórdios da colonização portuguesa, os presépios logo tiveram de adaptar-se à realidade local, circunstância muito propícia ao aparecimento de concepções heterodoxas e ao emprego de elementos exóticos da fauna e flora de cada região. Como registros envolvendo insetos são muito pouco comuns, chama a atenção que fêmeas de saúva, Atta sp. (Hymenoptera, Formicidae), tenham sido aproveitadas na composição de presépios no estado de São Paulo. Tendo subsistido pelo menos até a década 1960, os "presépios de formigas" existentes em cidades como Embu das Artes poderiam estar relacionados às "formigas vestidas" criadas por Jules Martin, curiosa manufatura paulistana do último quartel do século XIX.Present in Brazil since the beginning of Portuguese colonization, crèche nativity scenes were soon adapted to local reality, a propitious circumstance for the appearance of heterodox conceptions and the use of exotic elements of the fauna and flora peculiar to each region. As records about insects are very uncommon, it is noteworthy that females of leaf-cutting ants, Atta sp. (Hymenoptera, Formicidae), were used to compose crèche nativity scenes in São Paulo State. Having subsisted at least up to the decade of 1960, the "ant crèches" of cities such as Embu das Artes could be related to the then famous "dressed ants" created by Jules Martin, a curious manufacture of the city of São Paulo in the last quarter of the 19th century
Predicting the Proteins of Angomonas deanei, Strigomonas culicis and Their Respective Endosymbionts Reveals New Aspects of the Trypanosomatidae Family
Endosymbiont-bearing trypanosomatids have been considered excellent models for the study of cell evolution because the host protozoan co-evolves with an intracellular bacterium in a mutualistic relationship. Such protozoa inhabit a single invertebrate host during their entire life cycle and exhibit special characteristics that group them in a particular phylogenetic cluster of the Trypanosomatidae family, thus classified as monoxenics. in an effort to better understand such symbiotic association, we used DNA pyrosequencing and a reference-guided assembly to generate reads that predicted 16,960 and 12,162 open reading frames (ORFs) in two symbiont-bearing trypanosomatids, Angomonas deanei (previously named as Crithidia deanei) and Strigomonas culicis (first known as Blastocrithidia culicis), respectively. Identification of each ORF was based primarily on TriTrypDB using tblastn, and each ORF was confirmed by employing getorf from EMBOSS and Newbler 2.6 when necessary. the monoxenic organisms revealed conserved housekeeping functions when compared to other trypanosomatids, especially compared with Leishmania major. However, major differences were found in ORFs corresponding to the cytoskeleton, the kinetoplast, and the paraflagellar structure. the monoxenic organisms also contain a large number of genes for cytosolic calpain-like and surface gp63 metalloproteases and a reduced number of compartmentalized cysteine proteases in comparison to other TriTryp organisms, reflecting adaptations to the presence of the symbiont. the assembled bacterial endosymbiont sequences exhibit a high A+T content with a total of 787 and 769 ORFs for the Angomonas deanei and Strigomonas culicis endosymbionts, respectively, and indicate that these organisms hold a common ancestor related to the Alcaligenaceae family. Importantly, both symbionts contain enzymes that complement essential host cell biosynthetic pathways, such as those for amino acid, lipid and purine/pyrimidine metabolism. These findings increase our understanding of the intricate symbiotic relationship between the bacterium and the trypanosomatid host and provide clues to better understand eukaryotic cell evolution.Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)ERC AdG SISYPHEUniv Fed Rio de Janeiro, Inst Biofis Carlos Chagas Filho, Lab Ultraestrutura Celular Hertha Meyer, BR-21941 Rio de Janeiro, BrazilUniv Fed Rio de Janeiro, Inst Biofis Carlos Chagas Filho, Lab Metab Macromol Firmino Torres de Castro, BR-21941 Rio de Janeiro, BrazilLab Bioinformat, Lab Nacl Computacao Cient, Rio de Janeiro, BrazilINRIA Grenoble Rhone Alpes, BAMBOO Team, Villeurbanne, FranceUniv Lyon 1, CNRS, UMR5558, Lab Biometrie & Biol Evolut, F-69622 Villeurbanne, FranceUniv Estadual Campinas, Inst Biol, Dept Genet Evolucao & Bioagentes, São Paulo, BrazilUniv São Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Ciencias Farmaceut, São Paulo, BrazilLab Nacl Ciencia & Tecnol Bioetano, São Paulo, BrazilUniv Fed Minas Gerais, Inst Ciencias Biol, Dept Bioquim & Imunol, Belo Horizonte, MG, BrazilUniv Fed Goias, Inst Ciencias Biol, Mol Biol Lab, Goiania, Go, BrazilFundacao Oswaldo Cruz, Inst Carlos Chagas, Lab Biol Mol Tripanossomatideos, Curitiba, Parana, BrazilFundacao Oswaldo Cruz, Inst Carlos Chagas, Lab Genom Func, Curitiba, Parana, BrazilUniv Estadual Campinas, Ctr Pluridisciplinar Pesquisas Quim Biol & Agr, São Paulo, BrazilUniv Fed Minas Gerais, Inst Ciencias Biol, Dept Parasitol, Belo Horizonte, MG, BrazilUniv Fed Santa Catarina, Dept Microbiol Imunol & Parasitol, Ctr Ciencias Biol, Lab Protozool & Bioinformat, Florianopolis, SC, BrazilUniv Fed Vicosa, Dept Bioquim & Biol Mol, Ctr Ciencias Biol & Saude, Vicosa, MG, BrazilInst Butantan, Lab Especial Ciclo Celular, São Paulo, BrazilUniv São Paulo, Dept Biol, Fac Filosofia Ciencias & Letras Ribeirao Preto, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilWeb of Scienc
Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli
Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts. Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins. Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets
Livro Verde dos Montados
O Livro Verde dos Montados apresenta diversos objectivos que se interligam:
Em primeiro lugar, o Livro Verde pretende reunir e sistematizar, de uma forma simples e acessível ao público, o conhecimento produzido em Portugal pelos investigadores e técnicos de várias instituições de investigação ou de gestão que estudam o Montado. Assume-se como uma oportunidade de caracterizar o sistema tendo em conta as suas várias dimensões, identificando as principais ameaças à sua preservação assim como os caminhos que podem ajudar à sua sustentabilidade. Não sendo um documento científico, baseia-se no conhecimento científico e pretende constituir a base para uma plataforma de organização, tanto dos investigadores como do conhecimento científico actualmente produzido em Portugal sobre o Montado.Em segundo lugar, o Livro Verde deverá contribuir para um entendimento partilhado do que é o Montado, por parte do público, de técnicos e de especialistas, conduzindo a uma classificação mais clara do que pode ser considerado Montado e de quais os tipos distintos de Montados que podem ser identificados.
Em terceiro lugar, o Livro Verde estabelece as bases para uma estratégia coordenada de disponibilização de informação sobre o sistema Montado, visando o seu conhecimento, apreciação e valorização pela sociedade portuguesa no seu conjunto. Deste modo, o Livro Verde poderá constituir um instrumento congregador e inspirador para a realização de acções de sensibilização e informação sobre o Montado.
Em quarto lugar, pretende-se que o Livro Verde contribua para um maior reconhecimento e valorização do Montado como sistema, a nível do desenho das políticas nacionais por parte dos vários sectores envolvidos.Finalmente, o Livro Verde constituirá um documento parceiro do Livro Verde das Dehesas, produzido em Espanha em 2010, de forma a reforçar o reconhecimento e a devida valorização destes sistemas silvo-pastoris no desenho das estratégias e políticas relevantes pelas instituições europeias.
Em suma, os autores pretendem que o Livro Verde dos Montados se afirme como o primeiro passo para uma efectiva definição e implementação de uma estratégia nacional para os Montados
Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences
The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported
by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on
18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based
researchers who signed it in the short time span from 20 September to 6 October 2016
- …