New family of potentials with analytical twiston-like solutions

In this letter we present a new approach to find analytical twiston models. The effective two-field model was constructed by a non-trivial combination of two one field systems. In such an approach we successfully build analytical models which are satisfied by a combination of two defect-like solutions, where one is responsible to twist the molecular chain by $180^{\,0}$, while the other implies in a longitudinal movement. Such a longitudinal movement can be fitted to have the size of the distance between adjacent molecular groups. The procedure works nicely and can be used to describe the dynamics of several other molecular chains.Comment: 7 pages, 3 figure

Science-religion dialogue in education: religion teachers’ perceptions in a roman-catholic context

This paper examines the relationship between science and religion in the education system of Roman-Catholic Portuguese society. In particular, we explored perceptions of the relationship between science and religion for religious education teachers. We surveyed 198 Portuguese religious education teachers about how they view science and religion. The questionnaires’ results revealed a number of similarities: religious education teachers are highly involved in religious practices and exposed to science; they perceived a compatibility between science and religion; and they have an openness to dialogue between both. They do not adhere to anti-scientific perspectives, but they simultaneously try to limit what can be explained by science. Thus, an interpretative view of dialogue and/or integration seems to best explain the perceptions of religious education teachers of the relationship between science and religion. These findings allow a space of discussion, enabling teachers to possibly foster the science-religion dialogue in their contexts of pedagogical activity.info:eu-repo/semantics/acceptedVersio

Ferromagnetic tendency at the surface of CE charge-ordered manganites

Most previous investigations have shown that the surface of a ferromagnetic material may have antiferromagnetic tendencies. However, experimentally the opposite effect has been recently observed: ferromagnetism appears in some nano-sized manganites with a composition such that the antiferromagnetic charge-ordered CE state is observed in the bulk. A possible origin is the development of ferromagnetic correlations at the surface of these small systems. To clarify these puzzling experimental observations, we have studied the two-orbital double-exchange model near half-doping n=0.5, using open boundary conditions to simulate the surface of either bulk or nano-sized manganites. Considering the enhancement of surface charge density due to a possible AO termination (A = trivalent/divalent ion composite, O = oxygen), an unexpected surface phase-separated state emerges when the model is studied using Monte Carlo techniques on small clusters. This tendency suppresses the CE charge ordering and produces a weak ferromagnetic signal that could explain the experimental observations.Comment: 8 pages, 5 figure

Prognostic Factors of Tympanoplasty Type I in Pediatric Population – 4 Years Series of Dona Estefânia Hospital (HDE) of Centro Hospitalar Lisboa CentraL (CHLC –EPE)

Objetivos: Identificação de fatores de prognóstico em crianças submetidas a timpanoplastia tipo I. Materiais e métodos: Estudo retrospetivo baseado na análise de todos os processos clínicos de crianças atá aos 15 anos de idade, submetidas a timpanoplastia tipo I de Portmann durante um período de 4 anos. Resultados: Das 260 timpanoplastias realizadas neste período no serviço foram incluídos no estudo apenas 109 crianças. Das timpanoplastias realizadas, obteve-se sucesso cirúrgico em 68.8%, não se tendo identificado fatores de mau prognóstico cirúrgico com significância estatística. Conclusões: As timpanoplastias tipo I em crianças são um procedimento válido e com elevada taxa de sucesso, não tendo sido identificado qualquer fator de mau prognóstico cirúrgico com significado estatístico.info:eu-repo/semantics/publishedVersio

Testing the performance of warehousing rival policies through discrete event simulation

This research tested the performance of alternative warehouse designs concerning the picking process. Travel Distance and Total Fulfillment Time were the chosen measures. An explanatory case study was built up around a model implemented with SIMUL8. Hypotheses were set by selecting outcomes of the literature survey matching popular empirical findings. 15% reductions were found out for Total Fulfillment Time and Resource Utilisation, which was used as a proxy for operational efficiency. Literal replication of theoretical data patterns was considered as an internal validity sign. Assessing estimated changes benefits ahead of implementation was found out as a relevant contribution to practice.info:eu-repo/semantics/acceptedVersio

Irrigação do arroz de terras altas em função da porcentagem de cobertura do solo pela palhada, no sistema plantio direto.

Introdução; Coeficiente do tanque; Coeficiente de cultura; Controle de irrigação.bitstream/CNPAF/23535/1/circ_69.pd

Time Resolution and Linearity Measurements for a Scintillating Fiber Detector Instrumented with VLPC's

The time resolution for a charged particle detection is reported for a typical scintillating fiber detector instrumented with Rockwell HISTE-IV Visible Light Photon Counters. The resolution measurements are shown to agree with a simple Monte Carlo model, and the model is used to make recomendations for improved performance. In addition, the gain linearity of a sample of VLPC devices was measured. The gain is shown to be linear for incident light intensities which produce up to approximately 600 photoelectrons per event.Comment: 18 pages, 14 figures; Submitted to Nucl. Instr & Meth. in Phys. Res. A; Please direct correspondence to [email protected]

Statics and dynamics of an Ashkin-Teller neural network with low loading

An Ashkin-Teller neural network, allowing for two types of neurons is considered in the case of low loading as a function of the strength of the respective couplings between these neurons. The storage and retrieval of embedded patterns built from the two types of neurons, with different degrees of (in)dependence is studied. In particular, thermodynamic properties including the existence and stability of Mattis states are discussed. Furthermore, the dynamic behaviour is examined by deriving flow equations for the macroscopic overlap. It is found that for linked patterns the model shows better retrieval properties than a corresponding Hopfield model.Comment: 20 pages, 6 figures, Latex with postscript figures in one tar.gz fil

Transport on exploding percolation clusters

We propose a simple generalization of the explosive percolation process [Achlioptas et al., Science 323, 1453 (2009)], and investigate its structural and transport properties. In this model, at each step, a set of q unoccupied bonds is randomly chosen. Each of these bonds is then associated with a weight given by the product of the cluster sizes that they would potentially connect, and only that bond among the q-set which has the smallest weight becomes occupied. Our results indicate that, at criticality, all finite-size scaling exponents for the spanning cluster, the conducting backbone, the cutting bonds, and the global conductance of the system, change continuously and significantly with q. Surprisingly, we also observe that systems with intermediate values of q display the worst conductive performance. This is explained by the strong inhibition of loops in the spanning cluster, resulting in a substantially smaller associated conducting backbone.Comment: 4 pages, 4 figure