RESUMO
Using atomistic simulations, we have investigated the transport and annihilation of skyrmions interacting with a funnel array under a current applied perpendicular to the funnel axis. We find that transport without annihilation is possible at low currents, when the motion is dominated by skyrmion-skyrmion interactions and skyrmions push each other through the funnel opening. Skyrmion annihilation occurs for higher currents when skyrmions in the upper half of the sample exert pressure on skyrmions in the bottom half of the sample due to the external current. Upon interacting with the funnel wall, the skyrmions undergo a size reduction that makes it easier for them to pass through the funnel opening. We find five phases as a function of the applied current and the size of the funnel opening: (i) pinned, (ii) transport without annihilation, (iii) transport with annihilation, (iv) complete annihilation, and (v) a reentrant pinning phase that only occurs for very narrow openings. Our findings provide insight into how to control skyrmion transport using funnel arrays by delineating regimes in which transport of skyrmions is possible as well as the conditions under which annihilation occurs.
RESUMO
Avaliou-se o comportamento de genótipos de feijoeiro sob infestação de Bemisia tabaci (Genn.) biótipo B em condições de campo, nas épocas de cultivo "da seca" e "das águas". Utilizaram-se os genótipos IAC-Tybatã, IAC-Una, FT-Nobre, Pérola, LP 98-122, LP 02-130, LP 01-38, LP 9979, BRS-Pontal, BRS-Requinte, BRS-Triunfo, BRS-Grafite, CV-48 e Z-28. Adotou-se o delineamento de blocos casualizados com 14 tratamentos e três repetições. As avaliações foram realizadas semanalmente, contando-se o número de ovos e de ninfas de B. tabaci biótipo B em dez folíolos por parcela. Na safra "da seca" os genótipos menos ovipositados por B. tabaci biótipo B foram IAC-Una e LP 02-130 e os mais ovipositados foram os genótipos Z-28 e Pérola. As menores presenças de ninfas de mosca-branca foram observadas em LP 98-122 e FT-Nobre e as maiores em LP 01-38, Pérola e Z-28. Para a safra "das águas" os genótipos não diferiram entre si em relação ao ataque de B. tabaci biótipo B. Os fatores da produção apresentaram diferença estatística somente na safra das secas.
Bean genotypes were evaluated under the infestation of Bemisia tabaci (Genn.) biotype B under field conditions in the dry and rainy season. The genotypes used were IAC-Tybatã, IAC-Una, FT-Nobre, Pérola, LP 98-122, LP 02-130, LP 01-38, LP 9979, BRSPontal, BRS-Requinte, BRS-Triunfo, BRS-Grafite, CV-48 and Z-28. The experiment was arranged in randomized blocks with 14 treatments and 3 replications. The evaluations were made on a weekly basis by counting B. tabaci biotype B eggs and nymphs on 10 leaflets per plot. In the dry season the least oviposited genotypes by B. tabaci biotype B were IAC-Una and LP 02-130, while the most oviposited were Z-28 and Pérola. The least presence of nymphs of whitefly was observed on LP 98-122 and FT-Nobre, and the most on LP 01-38, Perola and Z-28. For the rainy season the genotypes did not differ in relation to the attack of B. tabaci biotype B. The yield factors presented a statistical difference only in the dry season.
Assuntos
Phaseolus/genética , Imunidade Vegetal/genética , Hemípteros/parasitologia , Repelentes de Insetos/análiseRESUMO
Fifty nine chronic chagasic patients were simultaneously submitted to xenodiagnosis and hemoculture for Trypanosoma cruzi samples isolations. The xenodiagnosis was done with 40 Panstrongylus megistus, Triatoma infestans and Dipetalogaster maximus nymphs, performing 120 triatomines. Groups of 10 insects per specie were dissecated and the intestinal content pooled and examined, after previous trituration and homogenization. The microscopically negative material was seed into LIT medium and examined after 20 days. Twenty nine patients were parasitologically proved, being 15 only by xenodiagnosis, 4 only by hemoculture and 10 by both methods. It was discussed the parasitological comprovation difficulties in chronic chagasic patients, the value of the simultaneous utilization of different triatomine species in xenodiagnosis and the hemoculture, in a favorable positive association to the sensitivity increase in the diagnosis' disease. The 49.2% of positivity obtained in this group, visualize approaches like clinic-therapeutic assay and or epidemiological (case-control) with the purpose to investigate a possible association with T. cruzi samples and different clinic forms in Chagas' disease.
