Misalignment-Resilient Propagation Model for Underwater Optical Wireless Links.

This paper proposes a multiple-lens receiver scheme to increase the misalignment tolerance of an underwater optical wireless communications link between an autonomous underwater vehicle (AUV) and a sensor plane. An accurate model of photon propagation based on the Monte Carlo simulation is presented which accounts for the lens(es) photon refraction at the sensor interface and angular misalignment between the emitter and receiver. The results show that the ideal divergence of the beam of the emitter is around 15° for a 1 m transmission length, increasing to 22° for a shorter distance of 0.5 m but being independent of the water turbidity. In addition, it is concluded that a seven-lense scheme is approximately three times more tolerant to offset than a single lens. A random forest machine learning algorithm is also assessed for its suitability to estimate the offset and angle of the AUV in relation to the fixed sensor, based on the power distribution of each lens, in real time. The algorithm is able to estimate the offset and angular misalignment with a mean square error of 5 mm (6 mm) and 0.157 rad (0.174 rad) for a distance between the transmitter and receiver of 1 m and 0.5 m, respectively.

Performance of phytosanitary products for control of soybean caterpillar.

The present work evaluated the efficiency of applied biological control and chemical control of Chrysodeixis includens, and the management of this looper caterpillar in the field soybean crop. The experimental design was a randomized complete block design, consisting of six treatments applied only once: two different doses of Bacillus thuringiensis (Bt), 0.2 and 0.35 L ha-1; Metarhizium rileyi strain UFMS 02 (Mr), 2.0 and 5.0 kg ha-1; insecticide Flubendiamide (Fd) 20 mL ha-1; and the control. The reduction of the pest and the percentage of efficiency of the products along the development of the soybean, besides some phytotechnical parameters, were evaluated thirteen days after the application. In general, there was a decrease in the number of caterpillars after thirteen days of spraying, with the Bt treatment being 350 mL ha-1, which provided the greatest reduction in the population (96.2%) when compared to the control (6.7 %). Regarding efficiency, treatments containing biological products Bt (two doses) and Mr 5.0 kg ha-1 provided the best results: 95.88, 84.69 and 92.35%, respectively. Among the phytotechnical parameters evaluated, the biological treatments were superior to the chemical treatments in relation to the productivity and the number of pods per plant, not differing statistically among them.

Selectivity of Entomopathogenic Fungi to Chrysoperla externa (Neuroptera: Chrysopidae).

We aimed to evaluate the selectivity of entomopathogenic fungi to larvae of Chrysoperla externa (Neuroptera: Chrysopidae). For this purpose, Beauveria bassiana (strain ESALQ PL63), Metarhizium anisopliae (strain ESALQ E9) and Metarhizium rileyi (strain UFMS 03) were assessed at different concentrations (1 × 107, 1 × 108 and 1 × 109 conidia mL-1). The control treatment consisted of distilled water and Tween80 0.01. The treatments were applied with a Potter spray tower using two different methodologies: direct application (DA) and dry film (DF). Up to 96 h after application, no treatment provided a larval mortality above 3%. After 120 h, only B. bassiana induced significant mortality in all instars, with rates of 26%, 17% and 10% for first, second and third instar larval periods, respectively. There was no difference regarding to the application method or concentration of conidia. The percentage of individuals that revealed changes in the length of the larval and pupal periods varied among different treatments with entomopathogenic fungi and control treatments, application methodologies and concentrations. Despite B. bassiana revealing a higher mortality than M. anisopliae and M. rileyi on larvae of C. externa, these three entomopathogenic fungi may be used in association with C. externa for sustainable pest management.

Interactions between Fungal-Infected Helicoverpa armigera and the Predator Chrysoperla externa.

The aim of the present study was to evaluate the interactions between Chrysoperla externa (Hagen, 1861) and the eggs and first-instar larvae of Helicoverpa armigera (Hübner 1805) infected by entomopathogenic fungi. The H. armigera eggs and larvae were treated with sterile distilled water + 0.01% Tween 80 (T1, control), Beauveria bassiana (Bals.) Vuill (T2), Metarhizium anisopliae (Metsch.) Sorok (T3), or Metarhizium rileyi (Farlow) Samson. (T4) at different concentrations (1 × 107, 1 × 108, and 1 × 109 con. mL-1). For each treatment, a single third-instar C. externa was offered prey (a combination of 80 eggs and 50 first-instar H. armigera larvae) at 0, 24, and 48 h after inoculation. Ten trials were completed for each treatment, and the entire experiment was repeated three times. Neither the concentrations of fungi nor the application method affected consumption by C. externa. Because all the predator larvae reached the pupal phase, with 100% viability in adults, these results suggest that entomopathogenic fungi and C. externa are compatible and that the simultaneous use of these biological control agents is possible for managing H. armigera.

Optical direct intensity modulation of a 79GHz resonant tunneling diode-photodetector oscillator.

We report on the direct intensity modulation characteristics of a high-speed resonant tunneling diode-photodetector (RTD-PD) with an oscillation frequency of 79 GHz. This work demonstrates both electrical and optical modulation and shows that RTD-PD oscillators can be utilized as versatile optoelectronic/radio interfaces. This is the first demonstration of optical modulation of an RF carrier using integrated RTD-PD oscillators at microwave frequencies.

Experimental evaluation of a digitized fiber-wireless system employing sigma delta modulation.

Digitized radio-over-fiber (D-RoF) transport schemes are being pointed as viable alternative solutions to their analog counterparts, in order to avoid distortion/dynamic range problems. Here we propose a novel D-RoF architecture that takes advantage of a bandpass sigma-delta modulator at the transmitter which subsequently permits the usage of a simpler/cheaper base station that avoids the employment of a digital to analog converter. The proposed architecture exploits the properties of the digital signal to enable the extraction of an higher carrier frequency through the employment of a bandpass filter. Furthermore, we present a comprehensive analysis regarding the impact of a low-cost electro-optic modulation on the quality of received demodulated signal. Finally, a comparison performance analysis between the conventional D-RoF and the proposed architecture is presented. We conclude that although the proposed architecture performs similarly to conventional D-RoF schemes, it is more competitive for either upgrading installed systems as well as for new deployments.

Rendimento de conídios e germinação de diferentes isolados de Metarhizium anisopliae (Metsch.) Sorok. (Ascomycota: Clavicipitaceae) cultivados em arroz / Yield of conidia and germination of different isolates of Metarhizium anisopliae (Metsch) Sorok. (Ascomycota: Clavicipitaceae) grown on rice

O objetivo desta pesquisa foi determinar a produção e a viabilidade de diferentes isolados de Metarhizium anisopliae em arroz. Foram colocados em sacos de polipropileno medindo 35 cm de comprimento e 22 cm de largura 100 g de arroz pré-cozido, imediatamente autoclavados a 120 °C, por 25 minutos. Após o resfriamento do arroz, inoculou-se 1 mL de uma suspensão contendo 1,0 x 109 conídios/mL de cada isolado testado, sendo acondicionados em câmara climatizada à temperatura de 25 ± 1°C, 70 ± 10% de UR e fotofase de 12 horas de incubação por 10 dias. Decorrido esse período, o arroz + fungo foi acondicionado em bandejas plásticas para promover a conidiogênese do fungo, dentro da câmara climática a 25 ± 1°C, 70 ± 10% de UR e fotofase de 12 horas. As bandejas ficaram empilhadas por quatro dias, cruzando-as por mais quatro dias. O isolado IBCB 425 foi o que mais produziu conídios em arroz com 1,82 x 109 conídios/g de arroz pré-cozido pelo método de bandeja. Com relação à viabilidade dos isolados, o IBCB 425 também apresentou maior capacidade de germinação dos conídios, com 94,84%.(AU)

In order to determine the production and viability of different isolates of Metarhizium anisopliae, 100 g of pre-cooked rice were placed in 35 cm long and 22 cm wide polypropylene bags, being immediately autoclaved at 120°C for 25 minutes. After cooling down, the rice was inoculated with 1 mL of a suspension containing 1,0 x 109 conidia/mL, packed in an incubator at 25 ± 1°C, 70 ± 10% RH and 12 hours of photophase. Plastic bags containing rice + fungus were incubated for 10 days. After this period, rice + fungus was packed in plastic trays to promote fungal conidiogenesis, within the climatic chamber at 2 5 ±1°C, 70 ± 10% RH and 12 hours of photophase. The trays were stacked for four days, being crossed for another four days. The IBCB 425 isolate was the most produced conidia on rice with 1.82 x 109 conidia/g of pre-cooked rice by the tray method. Regarding the viability of the isolates, IBCB 425 also showed a higher germination of conidia, with 94.84%.(AU)

Photo-detectors integrated with resonant tunneling diodes.

We report on photo-detectors consisting of an optical waveguide that incorporates a resonant tunneling diode (RTD). Operating at wavelengths around 1.55 µm in the optical communications C band we achieve maximum sensitivities of around 0.29 A/W which is dependent on the bias voltage. This is due to the nature of RTD nonlinear current-voltage characteristic that has a negative differential resistance (NDR) region. The resonant tunneling diode photo-detector (RTD-PD) can be operated in either non-oscillating or oscillating regimes depending on the bias voltage quiescent point. The oscillating regime is apparent when the RTD-PD is biased in the NDR region giving rise to electrical gain and microwave self-sustained oscillations Taking advantage of the RTD's NDR distinctive characteristics, we demonstrate efficient detection of gigahertz (GHz) modulated optical carriers and optical control of a RTD GHz oscillator. RTD-PD based devices can have applications in generation and optical control of GHz low-phase noise oscillators, clock recovery systems, and fiber optic enabled radio frequency communication systems.

Potencial reprodutivo de Chrysoperla externa (Hagen) (Neuroptera, Chrysopidae) em função do número de indivíduos por unidade de criação / Reproductive capacity of Chrysoperla externa (Hagen) (Neuroptera, Chrysopidae) in function of the number of individuals per unit of rearing

This work was carried out to investigate the reproductive potential of Chrysoperla externa subjected to different densities per rearing unit. Adults of the F4 offspring were kept at 25 ± 1ºC, RH 70 ± 10 percent and 12 h photophase. It was used the following densities per rearing unit (10 cm of diameter by 23 cm of height, and volume of 1650 cm³): 1 male: 3 female, 2 males: 6 females, 3 males: 9 females and 4 males: 12 females. It was evaluated the pre-oviposition period, the daily and total oviposition per female and per rearing unit, the percentage of viable and infertile eggs percentage and the exploitation index per female and per rearing unit. The density 4 males: 12 females presented better exploitation when compared to the other densities thus equalizing the low values obtained for the mean and total egg laying per female.

Verificou-se o efeito de diferentes densidades de insetos por unidade de criação sobre o potencial reprodutivo de Chrysoperla externa. Utilizaram-se adultos da geração F4 mantidos a 25 ± 1ºC, 70 ± 10 por cento de UR e fotofase de 12 horas. Foram utilizadas as seguintes densidades por unidade de criação (10 cm de diâmetro por 23 cm de altura e volume de 1650 cm³): um macho e três fêmeas, dois machos e seis fêmeas, três machos e nove fêmeas e quatro machos e doze fêmeas. Avaliou-se o período de pré-oviposição, a oviposição diária e total por fêmea e por unidade de criação, as porcentagens de ovos viáveis e inférteis e o índice de aproveitamento, calculado por fêmea e por unidade de criação. A densidade quatro machos e doze fêmeas apresentou melhor aproveitamento da unidade de criação, compensando as reduções observadas nos valores de postura média e total por fêmea.

Seleção de isolados de Metarhizium anisopliae (Metsch.) sorok. contra a cigarrinha da raiz da cana-de-açúcar Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) em laboratório / Screening of Metarhizium Anisopliae (Metsch.) sorok. strains against the sugarcane root spittlebug Mahanarva Fimbriolata (Stål) (Hemiptera: Cercopidae) in laboratory

O corte mecanizado da cana-de-açúcar resulta num acúmulo da palhada depositada no solo, proporcionando temperatura e umidade favoráveis à cigarrinha-da-raiz, Mahanarva fimbriolata (Stål), que provoca sérios problemas devido a sua ocorrência generalizada e altas populações. A patogenicidade de 79 isolados do fungo Metarhizium anisopliae (Metsch.) Sorok, provenientes de diferentes hospedeiros e regiões do País, foi testada em laboratório. Dez ninfas da cigarrinha foram colocadas em placas de Petri (9 cm de diâmetro) contendo folhas de cana lavadas e pulverizadas com 1 ml de uma suspensão contendo 5 x 107 conídios/ml. Cada tratamento foi composto por cinco repetições. Após a pulverização, as placas foram colocadas em câmara climatizada a 25 ± 1ºC, 70 ± 10% de UR e fotofase de 12h. A mortalidade foi avaliada diariamente, calculando-se os índices de mortalidade acumulada total, confirmada e corrigida de cada tratamento. Os melhores isolados testados foram: IBCB 348, IBCB 351, IBCB 363, IBCB 408, IBCB 410, IBCB 418, IBCB 425 e IBCB 482, os quais apresentaram mortalidade confirmada igual ou superior a 70% seis dias após a pulverização.

The accumulated mulch on the soil resultant from the mechanized cutting of sugarcane promotes favorable temperature and moist to Mahanarva fimbriolata (Stål), a pest that causes serious problems due to its widespread occurrence and high populations. Seventy nine isolates of Metarhiziumanisopliae (Metsch.) Sorok. from different hosts and regions were tested for their pathogenicity. Ten spitlebugs were put in petri dishes (9 cm of diameter) containing sugarcane leaves sprayed with 1 ml of a suspension containing 5 x 107 conidia/ml. Five replicates were used per treatment. The petri dishes were kept at 25 ± 1°C, 70 ± 10% RH and 12h photophase. Insects were monitored daily to calculate total cumulative mortality, as well as corrected and confirmed mortality for each treatment. The best tested isolates were: IBCB 348, IBCB 351, IBCB 363, IBCB 408, IBCB 410, IBCB 418, IBCB 425 and IBCB 482, which showed confirmed mortality equal or higher than 70%, six days after spraying.