Conjugacy of Embeddings of Alternating Groups in Exceptional Lie Groups

We discuss conjugacy classes of embeddings of Alternating groups in Exceptional Lie groups. We settle the count of classes of embeddings in E8 of a subgroup Alt10 and its double cover. This involves computation and the reduction of the problems to relative eigenvector problems. We update previously published tables of embeddings. We comment on the improvements present in our table and on the remaining unsettled conjugacy questions

Filamin cross-linked semiflexible networks: Fragility under strain

The semiflexible F-actin network of the cytoskeleton is cross-linked by a variety of proteins including filamin, which contain Ig-domains that unfold under applied tension. We examine a simple semiflexible network model cross-linked by such unfolding linkers that captures the main mechanical features of F-actin networks cross-linked by filamin proteins and show that under sufficiently high strain the network spontaneously self-organizes so that an appreciable fraction of the filamin cross-linkers are at the threshold of domain unfolding. We propose an explanation of this organization based on a mean-field model and suggest a qualitative experimental signature of this type of network reorganization under applied strain that may be observable in intracellular microrheology experiments of Crocker et al.Comment: 4 Pages, 3 figures, Revtex4, submitted to PR

El Método de Halley

El método de Halley es un conocido método de orden tres para la resolución numérica de ecuaciones no lineales, que puede interpretarse como una modificación del método de Newton para acelerar su convergencia. En este trabajo se estudian con detalle distintos procedimientos que permiten llegar a la formulación del método de Halley (desarrollos de Taylor, interpolación hiperbólica, fracciones continuas, ), y se establecen también resultados teóricos sobre la convergencia local de dicho método, incluyendo resultados numéricos que ilustran los órdenes de convergencia probados.Departamento de Matemática AplicadaGrado en Matemática

Determinación de las características agronómicas de 6 Ecotipos de Pijuayo para Palmito (Bactris Gasipaes K.) con posibilidades de propagación y desarrollo en la zona del Pongo de Caynarachi - San Martín

El presente trabajo de investigación titulado “Determinación de las características agronómicas de 6 ecotipos de pijuayo para palmito (Bactris gasipaes K.) Con posibilidades de propagación y desarrollo en la zona del pongo de Caynarachi – San Martin” se realizó en sector condoryacu, caserío naranjal, a lo largo del eje carretero Pongo de Caynarachi – Yurimaguas, en los campos de la empresa agro industrial San Pedro entre los meses de enero del 2016 y marzo del 2017, con el objetivo de determinar las características de los ecotipos, con posibilidad de propagación que superase a los cultivos instalados en campo y una producción continúa de hijuelos como mínimo tres por planta, se realizó la investigación según la exigencia de la experimentación agrícola, para lo cual se aplicó el Diseño de bloque completos al azar con 4 repeticiones donde se evaluaron 6 ecotipos del pijuayo tipo yurimaguas sin espinas. Los parámetros evaluados fueron los siguientes: altura de planta, diámetro a 5 cm del suelo, numero de hojas, longitud de la hoja bandera, número de hijuelos y enfermedades fungosas. Se encontró que el Tratamiento T3 (Paranapura) presento las mejores características agronómicas por su precocidad y capacidad de desarrollo y así mismo este ecotipo presento una buena capacidad en la producción de hijuelos con un promedio de 4.83 hijuelos/planta, y el que presento la menor capacidad de hijuelos/planta fue Caynarachi con 1.08. Se encontró que el tratamiento T4 (Cuiparillo) y T2 (Yurimaguas) también presentaron una buena capacidad hijuelos/planta teniendo como promedio 3.58 y 3.09 respectivamente. Se determinó que las condiciones medio ambientales de la localidad del Pongo de Caynarachi son adecuadas para el desarrollo de los Ecotipos en estudio. Se determinó que la enfermedad que tuvo mayor incidencia en el desarrollo de los ecotipos de pijuayo en estudio fue (Rhizoctonia sp

Selection of peptide ligands binding to the basolateral cell surface of proximal convoluted tubules

Selection of peptide ligands binding to the basolateral cell surface of proximal convoluted tubules.BackgroundRecently, we have reported a novel approach of screening phage-display peptide libraries on microdissected intact renal tubular segments and identified an RGD-containing peptide ligand that specifically binds to the basolateral membrane of cortical collecting ducts (CCD). However, screening phage libraries on proximal convoluted tubules (PCT) did not yield a tubule segment-specific ligand. Here, we describe the successful modification of our previously developed phage-display approach and the identification of two distinct ligands that bind specifically to receptors expressed at the basolateral membrane of PCT.MethodsEx vivo screening of phage-display peptide libraries for specific ligands was adapted for PCT. The previously developed method was significantly extended by applying it to a distinct tubular segment, varying the number of rounds of biopanning and incubating phage libraries with absorber cells prior to biopanning. Binding specificity and cellular localization of selected peptide-displaying phage or the corresponding synthetic peptide were analyzed using various epithelial cell lines as well as competition assays and confocal immunofluorescence microscopy.ResultsScreening phage-display peptide libraries, depleted of ligands binding to ubiquitously expressed receptors by preincubation with HEK-293 cells, led to the identification of two PCT-specific ligands. Phage expressing peptides with the consensus sequence GV(K/R)GX3(T/S) or RDXR mediated 15-fold and 13-fold higher binding to PCT than control phage, and binding to PCT was 13-fold and 21-fold higher than binding to CCD, respectively. Neither phage mediated significant binding to various epithelial cell lines, and binding of both ligands was abolished by the addition of the corresponding synthetic peptide. Immunofluorescence experiments revealed a submembrane localization of both ligands upon incubation with PCT.ConclusionsExploiting the versatility of phage-display and biopanning allowed the identification of two distinct peptide ligands that bind specifically to the basolateral membrane of PCT. Tubule segment-specific ligands, such as the described PCT ligands, may be useful for the analysis of cell-extracellular matrix interactions and may contribute to the development of new therapeutic strategies for renal diseases

Unfolding cross-linkers as rheology regulators in F-actin networks

We report on the nonlinear mechanical properties of a statistically homogeneous, isotropic semiflexible network cross-linked by polymers containing numerous small unfolding domains, such as the ubiquitous F-actin cross-linker Filamin. We show that the inclusion of such proteins has a dramatic effect on the large strain behavior of the network. Beyond a strain threshold, which depends on network density, the unfolding of protein domains leads to bulk shear softening. Past this critical strain, the network spontaneously organizes itself so that an appreciable fraction of the Filamin cross-linkers are at the threshold of domain unfolding. We discuss via a simple mean-field model the cause of this network organization and suggest that it may be the source of power-law relaxation observed in in vitro and in intracellular microrheology experiments. We present data which fully justifies our model for a simplified network architecture.Comment: 11 pages, 4 figures. to appear in Physical Review

One- and two-particle microrheology

We study the dynamics of rigid spheres embedded in viscoelastic media and address two questions of importance to microrheology. First we calculate the complete response to an external force of a single bead in a homogeneous elastic network viscously coupled to an incompressible fluid. From this response function we find the frequency range where the standard assumptions of microrheology are valid. Second we study fluctuations when embedded spheres perturb the media around them and show that mutual fluctuations of two separated spheres provide a more accurate determination of the complex shear modulus than do the fluctuations of a single sphere.Comment: 4 pages, 1 figur

Direito autoral de criações feitas por inteligência artificial: diferentes percepções para o mesmo dilema

A Inteligência Artificial (IA) tem possibilitado grandes avanços em diversos campos da ciência e atividades do cotidiano da sociedade, principalmente pela capacidade de realizar tarefas de forma mais rápida e mais eficaz em comparação ao desempenho humano, entretanto existe um dilema acerca da autoria de uma criação feita por IA. Para esclarecer esta questão, este trabalho foi idealizado com o objetivo de identificar as diferentes percepções sobre o tratamento dado ao direito autoral de criações de IA, do ponto de vista de estudiosos do campo da Propriedade Intelectual, cortes judiciais e o poder legislativo de alguns países e as disposições legais brasileiras atualmente disponíveis para solucionar esse impasse no Brasil. A metodologia utilizada no trabalho foi a pesquisa bibliográfica e documental, para coletar artigos científicos e documentos governamentais que tratassem da temática. Os resultados demonstraram que existem quatro posicionamentos distintos para o autor: o criador da IA, o usuário da IA, o criador do banco de dados que alimentou a IA e ninguém, ou seja, a obra fará parte do domínio público, sendo esta a opção que mais obteve registros na pesquisa realizada em dez países pesquisados