We use Chen iterated line integrals to construct a topological algebra A p of separating functions on the Group of Loops LM p . A p has an Hopf algebra structure which allows the construction of a group structure on its spectrum. We call this topological group, the group of generalized loops LM p .Then we develope a Loop Calculus, based on the Endpoint and Area Derivative Operators, providing a rigorous mathematical treatment of early heuristic ideas of Gambini, Trias and also Mandelstam, Makeenko and Migdal. Finally we define a natural action of the "pointed" diffeomorphism group Dif f p (M) on LM p , and consider a Variational Derivative which allows the construction of homotopy invariants.This formalism is useful to construct a mathematical theory of Loop Representation of Gauge Theories and Quantum Gravity.
SUMMARY:Sporadic gastric carcinomas (SGC) with microsatellite instability (MSI) exhibit mutations in target genes and display a particular clinicopathological profile. In SGC the MSI phenotype has been associated with hMLH1 promoter hypermethylation. Fifty-seven SGC, classified as high-frequency MSI (MSI-H), low-frequency MSI (MSI-L), and microsatellite stable (MSS), were analyzed for hMLH1 promoter methylation status and clinicopathological features. hMLH1 mutations and hMLH1 expression, as well as target gene mutations, were also evaluated. Our aims were to characterize the molecular and clinicopathological features of SGC, with and without hMLH1 promoter hypermethylation, and to compare the molecular and clinicopathological features of MSI-L, MSI-H, and MSS tumors in an attempt to clarify the place of MSI-L tumors in the mismatch repair (MMR) pathway. Hypermethylation of hMLH1 promoter occurred in 27 of 57 SGC (47.3%) and was significantly associated with MSI status, target gene mutations, and expansive pattern of growth of the tumors. Seventy-five percent of the MSI-H and 50% of MSI-L carcinomas showed hypermethylation (Metϩ) of hMLH1 in contrast to 0% in MSS carcinomas. No hMLH1 expression was observed in MSI-L/Metϩ and MSI-H/Metϩ cases. MSS and MSI-L tumors share the same clinicopathological profile regardless of the methylation status of the latter and are distinct from MSI-H tumors. We conclude that mutations in target genes, more than hypermethylation or absence of expression of hMLH1, are the link between MSI status and most of the clinicopathological features of SGC. (Lab Invest 2000, 80:1915-1923.
Rao et al.'s mandibular canine index (MCI) is a simple odontometric method which uses the mandibular canine as the key to sex estimation. This index is defined as the ratio between the right canine mesiodistal dimension and the mandibular canine arch width. The aim of this study was to contribute to sex estimation using dental techniques by analysing the MCI efficiency, and to propose a new approach for its use. Measurements were taken from 120 plaster casts (70 females) in the 16-30 year age group. Although statistically significant sexual dimorphism was observed in both the mesiodistal dimension and the mandibular canine arch width, the MCI showed a low accuracy in sex classification (54.2% correct identifications). This accuracy was improved to 64.2% using receiver operating characteristics curve analysis. Yet, despite the better accuracy, these results reinforce the idea that the MCI may not be particularly useful in sex prediction, since it may not reflect the same degree of sexual dimorphism as its absolute measures.
This paper presents a class of packing problems where circles may be placed either inside or outside other circles, the whole set being packed in a rectangle. This corresponds to a practical problem of packing tubes in a container. Before being inserted in the container, tubes may be put inside other tubes in a recursive fashion. A variant of the greedy randomized adaptive search procedure is proposed for tackling this problem, and its performance is assessed in a set of benchmark instances.
CITAÇÃOTavares, JN (2017) Modelo SIR em epidemiologia, Rev. Ciência Elem., V5 (02) Neste pequeno texto, procura-se ilustrar, através de um modelo simples (SIR), como a Matemática pode serútil na previsão da evolução de uma epidemia e na tomada de decisão sobre estratégias de combate à sua propagação (vacinação, quarentenas, etc.). INTRODUÇÃO Ao longo dos séculos, tem havido muitos exemplos de epidemias de várias doenças com efeitos dramáticos na população humana (e não só). Uma das mais conhecidas é aPeste Negra na Europa no século XIV 1 , que dizimou entre 25 a 75 milhões de pessoas (cerca de um terço da populacão europeia da altura!). Nos tempos coloniais, a propagação de doenças europeias, tais como o sarampo e a varíola, teve um impacto desastroso sobre certas populacões indígenas que não tinham desenvolvido resistência a essas doenças.Hoje em dia, existem ainda exemplos trágicos -a SIDA, o vírus Ébola, o ZIKA e muitos outros.Se conseguirmos compreender como uma doença se propaga numa determinada população, então estaremos melhor equipados para a conter, através de vacinação ou quarentena. 1.2.Muitas doenças são propagadas por indivíduos infectados que, por contacto com in-divíduos susceptíveis, os contagiam. Estas incluem gripe, sarampo, varicela, febre glandular e SIDA. Por outro lado, a malária é transmitida por meio de um hospedeiro, um mosquito, que transporta a doença de indivíduo para indivíduo. Algumas doenças são mais contagiosas do que outras. Sarampo e gripe são altamente contagiosas, enquanto a febre glandular é muito menos. Muitas doenças, tais como papeira e sarampo, conferem uma imunidade ao longo da vida; no entanto, gripe e febre tifóide têm períodos curtos de imunidade e podem ser contraídas mais do que uma vez. 1.3.Comecemos por esclarecer alguns conceitos prévios que surgem recorrentemente na modelação de epidemias.• O período de incubação da doença é o tempo entre a infecção e a aparência visível de sintomas. Isto não deve ser confundido com o
Following the ideas ofÉlie Cartan (1928), we use Cartan's equivalence method and the notion of Cartan's affine generalized space and development to geometrize non holonomic mechanics. 1
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