5 research outputs found
Neuromorphometric characterization with shape functionals
This work presents a procedure to extract morphological information from
neuronal cells based on the variation of shape functionals as the cell geometry
undergoes a dilation through a wide interval of spatial scales. The targeted
shapes are alpha and beta cat retinal ganglion cells, which are characterized
by different ranges of dendritic field diameter. Image functionals are expected
to act as descriptors of the shape, gathering relevant geometric and
topological features of the complex cell form. We present a comparative study
of classification performance of additive shape descriptors, namely, Minkowski
functionals, and the nonadditive multiscale fractal. We found that the proposed
measures perform efficiently the task of identifying the two main classes alpha
and beta based solely on scale invariant information, while also providing
intraclass morphological assessment
Algebraic methods in molecular science
O espectro vibracional do monofluoracetileno (HCCF) e do monocloroacetileno (HCCCl) são calculados por meio de técnicas algébricas sob a hipótese de que eles resultam de uma simetria u(4) dada pela cadeia u(4) ⊃ so(4) ⊃ so(3). Os resultados são comparados com as 170 linhas vibracionais experimentais disponíveis para o HCCF e com as 23 disponíveis para o HCCCL. Os desvios médios encontrados de 7 cm-1 e 4 cm-1, respectivamente, estabelecem estes sistemas como os melhores exemplos de simetria dinâmica em Física Molecular até o momento. Numa outra aplicação de técnicas algébricas, tendo em mente aplicações que requerem a manipulação de diferentes representações irredutíveis, nós calculamos fórmulas fechadas e analíticas para os elementos de matriz dos geradores da álgebra simplética sp(4,C) atuando numa representação irredutível arbitrária da cadeia sp(4,C) ⊃ sp(2,C) ⊕sp(2, C), a qual está sendo utilizada no estudo do código genético. A base utilizada é ortogonal e é análoga à base de Gel\'fand- Tsetlin para as álgebras unitárias.The vibrational spectrum of monofluoroacetylene (HCCF) and of monochloroacetylene (HCCCl) are calculated by means of algebraic techniques under the hypothesis that they result from a U(4) symmetry through the chain U(4) symmetry through the chain U(4) ⊃ O(4) ⊃ O(3). The results are compared with the 170 experimentally available vibrational lines for the HCCF and with the 23 experimentally available vibrational lines for the HCCCl. The mean square deviation is founded to be 7 cm-1 and 4 cm-1, respectivelly, establishing these spectra as the best examples of a dynamical symmetry reported in Molecular Physics so far. In another application of algebraic techniques, having in mind applications in which the algebraic handling of several different irreducible representations are necessary, we provide closed formulas for the matrix elements of the symplectic sp(4,C) Lie algebra on an arbitrary irreducible representation on the chain sp(4,C) ⊃ sp(2,C) ⊕ sp(2,C), which is being used in the study of the genetic code by Lie algebras. The used basis is orthogonal and analogous to the Gel\'fand- Tsetlin basis of unitary algebras
Algebraic methods in molecular science
O espectro vibracional do monofluoracetileno (HCCF) e do monocloroacetileno (HCCCl) são calculados por meio de técnicas algébricas sob a hipótese de que eles resultam de uma simetria u(4) dada pela cadeia u(4) ⊃ so(4) ⊃ so(3). Os resultados são comparados com as 170 linhas vibracionais experimentais disponíveis para o HCCF e com as 23 disponíveis para o HCCCL. Os desvios médios encontrados de 7 cm-1 e 4 cm-1, respectivamente, estabelecem estes sistemas como os melhores exemplos de simetria dinâmica em Física Molecular até o momento. Numa outra aplicação de técnicas algébricas, tendo em mente aplicações que requerem a manipulação de diferentes representações irredutíveis, nós calculamos fórmulas fechadas e analíticas para os elementos de matriz dos geradores da álgebra simplética sp(4,C) atuando numa representação irredutível arbitrária da cadeia sp(4,C) ⊃ sp(2,C) ⊕sp(2, C), a qual está sendo utilizada no estudo do código genético. A base utilizada é ortogonal e é análoga à base de Gel\'fand- Tsetlin para as álgebras unitárias.The vibrational spectrum of monofluoroacetylene (HCCF) and of monochloroacetylene (HCCCl) are calculated by means of algebraic techniques under the hypothesis that they result from a U(4) symmetry through the chain U(4) symmetry through the chain U(4) ⊃ O(4) ⊃ O(3). The results are compared with the 170 experimentally available vibrational lines for the HCCF and with the 23 experimentally available vibrational lines for the HCCCl. The mean square deviation is founded to be 7 cm-1 and 4 cm-1, respectivelly, establishing these spectra as the best examples of a dynamical symmetry reported in Molecular Physics so far. In another application of algebraic techniques, having in mind applications in which the algebraic handling of several different irreducible representations are necessary, we provide closed formulas for the matrix elements of the symplectic sp(4,C) Lie algebra on an arbitrary irreducible representation on the chain sp(4,C) ⊃ sp(2,C) ⊕ sp(2,C), which is being used in the study of the genetic code by Lie algebras. The used basis is orthogonal and analogous to the Gel\'fand- Tsetlin basis of unitary algebras
The monofluoracetylene spectrum in the vibron model
Descrição do espectro vibracional da molécula linear HCCF (monofluoracetileno) via uma simetria dinâmica SU(4) no modelo dos vibrons.Description of the vibrational spectra of the linear molecule HCCF (monofluoroacetylene) via a SU(4) dynamical symmetry in the vibron model
The monofluoracetylene spectrum in the vibron model
Descrição do espectro vibracional da molécula linear HCCF (monofluoracetileno) via uma simetria dinâmica SU(4) no modelo dos vibrons.Description of the vibrational spectra of the linear molecule HCCF (monofluoroacetylene) via a SU(4) dynamical symmetry in the vibron model