Aroldo Gomes Filho

All-Optical Half-Adder Using All-Optical XOR and AND Gates for Optical Generation of “Sum” and “Carry”

Abstract In this article, a numerical simulation study using the symmetric planar three-core non-linear directional coupler, operating with a short light pulse (2 ps), for the implementation of an all-optical half-adder is presented. The half-adder is the key building block for many digital processing functions such as shift register, binary counter, and serial parallel data converters. Optical couplers are an important component for application in optical fiber telecommunication systems and all integrated optical circuits because of very high switching speeds (as high as the femto-second range). In this numerical simulation, the symmetric planar three-core non-linear directional coupler presents a planar symmetrical structure with three cores in a parallel equidistant arrangement, three logical inputs (CP, A, and B), and two output logic functions (C and S). The CP(ΔΦ) input is a control pulse with a phase difference ΔΦ = Δθπ (0 ≤ Δθ ≤ 2) between inputs A and B (logical inputs of the half-adder) and one amplitude discriminator circuit. The half-adder uses two output logic functions of Sum(S) and Carry(C), which can be demonstrated by using XOR and AND gates, respectively. For the half-adder, the phase [ΔΦMIN, ΔΦMAX] intervals are studied, allowing the operation of the device as a half-adder. For the selected range of CP(ΔΦBETTER), the extinction ratio was studied, the compression factors for both Sum(S) and Carry(C) outputs of the symmetric planar three-core non-linear directional coupler.

Marcadores moleculares RAPD e descritores morfológicos na avaliação da diversidade genética de goiabeiras (Psidium guajava L.)

The knowledge of the genetic and phenotypic variability among different accessions of guava is important for supporting improvement programs of this specie in northern Rio de Janeiro state, which needs new cultivars able to generate income for local farmers. This work aimed to evaluate the genetic divergence among six cultivars and 19 accessions of guava via RAPD molecular markers and morphological characteristics. One hundred and seventeen polymorphic markers were obtained from 28 primers. The results showed a partial agreement between the methods of studied groupings, with the formation of 12 groups. The accessions ‘Vita 3’and ‘6’ were the most divergent, showing genetic distance of 0.663. The comparative analysis of groupings showed that RAPD markers and morphological descriptors were effective in discriminating the accessions and to show potential genetic variability useful in genetic improvement programs.

Logic gates based in asymmetric couplers : Numerical analysis

Abstract In this work, we present a numerical investigation of the transmission and switching of fundamental solitons in asymmetric nonlinear directional couplers, constructed with dispersion decreasing fibers (DDF). In this configuration, the coupler consists of two separated parallel fibers, one with a DDF profile and the other with a constant profile. We obtained the characteristics of transmission, extinction ratio, and compression factor of the device. The truth tables for the logic gates AND, OR, and XOR were obtained. We concluded that the device presenting a constant profile provided the best performance of the studied logic gates. Logic gates AND, OR, and XOR operating with extinction coefficient around 16.6 dB were obtained.

Add-Drop Demultiplexer Operating in an Optical Michelson Interferometer Based in Fiber Bragg Gratings for Time Division Multiple Access Systems

Abstract This article presents a numerical investigation of the propagation and switching of ultra-short pulses (∼2 ps) using a fiber-optic Michelson interferometer. In this study, the performance of the Michelson interferometer is studied as a function of the non-linear characteristics of the coupler and the fiber Bragg gratings. The numerical studies were done starting from the coupled-mode equations solved using the fourth-order Runge–Kutta method. The switching characteristic of the short pulses was examined as a function of pump power and the dephasing in the reflection amplitude of one of the Bragg gratings in order to obtain an add–drop filter operation. Transmission characteristics, such as cross-talk level, extinction ratio coefficient, and compression factor, were analyzed for different dephasing values and pump powers. Pump powers were examined from below the critical power of the coupler of switching (P = 1 W), at the critical power of switching (Pc = 1.73 W), and above (P = 1.95 W). Through this study, one can verify that the transmission, cross-talk level, extinction coefficient, and compression factor depend on the pump power inserted into the device and in the dephasing. The optical fiber Michelson interferometers with identical gratings in the two output arms implement important components as a demultiplexer in add–drop devices. This device has attracted great interest in the field of all-optical switching in telecommunications for operating with high transmission rates.

Mancha fisiologica e produtividade do mamão Tainung 01: efeito da lâmina de irrigação e cobertura do solo

Nesse experimento avaliou-se o efeito de diferentes lâminas de irrigacao e coberturas do solo, sobre a incidencia da mancha fisiologica do mamao e aspectos de producao do mamao cv. Tainung 01, no periodo de dezembro de 2003 a novembro de 2004. Utilizou-se delineamento em blocos casualizados em esquema fatorial. Quando as interacoes foram significativas desdobraram-se as mesmas e efetuaram-se as comparacoes das medias, via Teste Tukey. Os resultados encontrados demonstram uma alta correlacao entre os fatores estudados e a epoca de colheita. Com relacao a mancha fisiologica do mamoeiro confirmou-se o aspecto sazonal de incidencia, sendo que, a cv. Tainung 01 apresentou a maior incidencia do disturbio, nos meses de setembro e outubro. Com relacao as coberturas de solo, a cobertura morta se mostrou promissora para as variaveis de producao, ao contrario da cobertura verde com a leguminosa Arachis pintoi, pois a mesma competiu com o mamoeiro acarretando, assim, reducao na produtividade.

RAPD molecular markers and morphological descriptors in the evaluation of genetic diversity of guava (Psidium guajava L.).

The knowledge of the genetic and phenotypic variability among different accessions of guava is important for supporting improvement programs of this specie in northern Rio de Janeiro state, which needs new cultivars able to generate income for local farmers. This work aimed to evaluate the genetic divergence among six cultivars and 19 accessions of guava via RAPD molecular markers and morphological characteristics. One hundred and seventeen polymorphic markers were obtained from 28 primers. The results showed a partial agreement between the methods of studied groupings, with the formation of 12 groups. The accessions ‘Vita 3’and ‘6’ were the most divergent, showing genetic distance of 0.663. The comparative analysis of groupings showed that RAPD markers and morphological descriptors were effective in discriminating the accessions and to show potential genetic variability useful in genetic improvement programs.

Genetic diversity of barbados cherry (Malphigia emarginata D. C.), with RAPD molecular markers and morpho-agronomical characteristics

The knowledge on genetic variability and the relationship among different Barbados cherry accesses is important to maximize the resources for the future genetic breeding. The objective of this work was to determine the genetic variability among 48 accessions of Barbados cherry evaluated using RAPD as DNA markers and morpho-agronomical characteristics. It was used 25 primers, making it possible to obtain 108 markers and to generate 92 different polymorphic products. The obtained markers were of analyzed by the method of Tocher and UPGMA what generated a dendrogram using the Jaccard index. There was a concordance among the studied methods with the formation of 14 groups. The accessions ACE 023 and ACE 033 were the most distinct, presenting a genetic dissimilarity of 0.58. The results allowed to us to conclude that RAPD marker associated with morpho-agronomical characteristics were efficient to discriminate the genetic relationship among the accessions of Barbados cherry and the divergent accessions should be useful in the use of genetic breeding and six of them were recommended for future clonal evaluation as varieties and clonal propagation.

Validação do método das notas para quantificação da incidência da mancha fisiológica do mamão através do uso de imagens digitais

In this experiment the ImageJ software version 1.32j was used to quantify the incidence of the skin freckles on papaya with the objective of survey the method of numerical scale, since the same it a subjective method. The experiment consisted of a completely randomized design in a factorial arrangement of 3x6, with three cultivars (Golden, Diva and Tainung 01) and six numerical values (from 0 to 5; being 0 to the absence of skin freckles incidence and 5 to the maximum occurrence of skin freckles incidence). The results were statistically interpreted using regression analysis and single factor analyses of variance. It was sampled 10 fruits per cultivar, and per numerical value, totalizing 180 analyzed fruits being the results evaluated through the Genes software. The results show that the numerical scale method can be used, since it provides trusting results, being well precise to quantify the level of skin freckles incidence on papaya.

Numerical analysis in triangular and planar three-core nonlinear optical fiber couplers (TNLDC) operating logical gates

In this paper, we investigate the switching process in triangular symmetric and planar symmetric three-core nonlinear fiber coupler (TNLDC) and we have numerically shown, via the coupled nonlinear Schrodinger equations (NLSEs), that logic gates AND, OR and NXOR can be constructed from a triangular TNLDC while the planar TNLDC produced logical gates AND, NAND, OR, and XOR. We consider two basic models. The first, one triangular symmetrical structure with three cores in an equilateral-triangle arrangement and using a control signal (CS) applied to the first core and the second model present a transverse symmetrical structure with three cores in a parallel equidistant arrangement (or planar symmetrical structure), however the position of the control signal (CS) is applied to the input of the first fiber (core 1). Looking at the transmission characteristics of the device, through the direct and cross channel, we did a study of the extinction ratio (Xratio) of these devices. In comparing the performance of both switches operating as logic gates we will use the figure-of-merit of the logic gates [FOMELG(dB)] defined as a function of the extinction ratio of the gate outputs.

Marcadores moleculares RAPD e descritores morfológicos na avaliação da diversidade genética de goiabeiras ( Psidium guajava L.) - doi: 10.4025/actasciagron.v32i4.4720

The knowledge of the genetic and phenotypic variability among different accessions of guava is important for supporting improvement programs of this specie in northern Rio de Janeiro state, which needs new cultivars able to generate income for local farmers. This work aimed to evaluate the genetic divergence among six cultivars and 19 accessions of guava via RAPD molecular markers and morphological characteristics. One hundred and seventeen polymorphic markers were obtained from 28 primers. The results showed a partial agreement between the methods of studied groupings, with the formation of 12 groups. The accessions ‘Vita 3’and ‘6’ were the most divergent, showing genetic distance of 0.663. The comparative analysis of groupings showed that RAPD markers and morphological descriptors were effective in discriminating the accessions and to show potential genetic variability useful in genetic improvement programs.