This paper presents bees algorithm (BA) for null steering of linear antenna arrays by controlling only the element positions. The BA is an optimization algorithm inspired by the natural foraging behavior of honey bees to find the optimal solution. To show the versatility and flexibility of the proposed BA, several examples of Chebyshev array pattern with the imposed single, multiple and broad nulls are given. It is found that the nulling technique based on BA is capable of steering the array nulls precisely to the undesired interference directions. For practical consideration, the sensitivity of the produced patterns due to small variations of the element positions is also examined by rounding the element position values to the second decimal position.
In Italy, food-borne outbreaks of opisthorchiasis have occurred since 2003, all of them originating from some lakes in Central Italy where the only European liver fluke, Opisthorchis felineus (Rivolta, 1884) is endemic. The aim of the present study is to investigate the factors that may facilitate the life cycle of O. felineus in the area of Bolsena Lake, the knowledge of the local population about opisthorchiasis, and preventative healthcare measures. We performed a descriptive observational study through the submission of questionnaires to three target populations: fishermen who fish exclusively in Bolsena Lake, restaurateurs whose businesses are close to the lake and general population living in the province of Viterbo. Results showed hazardous behaviours and eating habits in the three target populations, as well as a poor knowledge of opisthorchiasis and preventative healthcare measures., Paola Scaramozzino, Roberto Condoleo, Enrica Martini, Teresa Bossù, Silvia Aquilani, Valentina Spallucci, Elisabetta Aquilini, Selene Marozzi., and Obsahuje bibliografii
1_Certain monoterpenes produced by aromatic plants are known to have lethal and sublethal effects on insects. As there is a need to replace conventional pesticides (organophosphates, carbamates, pyrethroids) with biorational pesticides, we evaluated the behavioural and toxicological responses of the German cockroach, Blattella germanica, exposed to the following monoterpenes, namely (+)-a-pinene, (–)-a-pinene, limonene, menthone, linalool, menthyl acetate and geraniol. Locomotor activity and repellency were quantified using a video tracking system. To study the effect on locomotor activity, larvae were exposed to filter papers treated with concentrations of monoterpenes ranging between 1.4 and 1,400 µg/cm2. Only menthyl acetate applied at a concentration of 14 µg/cm2 or higher increased the locomotor activity of the larvae. Repellency was evaluated by exposing larvae to circles of filter paper divided in two equal zones: one zone was treated with a solution of a monoterpene in acetone (14 or 140 µg/cm2) and the other with only acetone. Larvae were repelled by all the monoterpenes tested. The two concentrations of geraniol and the highest concentration of menthyl acetate and linalool were as repellent as DEET (positive control). The fumigant effect was evaluated by exposing larvae to vapour from 100 µl of pure monoterpene in a sealed container., 2_The values of the 50% Knock-down Times (KT50), expressed in minutes, were: (+)-a-pinene: 11.8, (–)-a-pinene: 14.6, limonene: 81.0, menthone: 141.0, and linalool: 238.6. (+)-a-Pinene was as good a fumigant as dichlorvos (positive control, KT50 = 9.7 min). The least effective compounds were menthyl acetate and geraniol (both affected less than 50% of larvae after 490 min of exposure). In conclusion, (+)-a-pinene (for its fumigant effect), menthyl acetate (for its hyperactivant effect) and menthone and geraniol (for their repellent properties) could potentially be used for controlling B. germanica., Raúl A. Alzogaray ... [et al.]., and Obsahuje seznam literatury
Larvae of the endangered Scarce Large Blue butterfly, Phengaris (Maculinea) teleius, are initially endophytic, feeding upon developing seeds of Sanguisorba officinalis, but complete their development as social parasites preying on the brood of Myrmica ants. Females show very specific preferences, laying eggs exclusively in young flower heads of the food plant. In the present contribution we report the results of a detailed study of female behaviour at three sites differing in size and abundance of S. officinalis. Tracked individuals switched between feeding on nectar (nectaring), flight and oviposition. They fed exclusively on flowers of reddish, pink or violet colouration, favouring Viccia cracca and S. officinalis. However, females spent about one fifth of the time they were active ovipositing and laid about 20 eggs per hour. Oviposition visits to flower heads were highly stereotyped and followed a specific ritual. Examination of accepted, rejected and randomly sampled flower heads showed that females avoided those containing conspecific eggs and at a site where this was difficult due to a shortage of suitable flower heads, they tended to distribute their eggs evenly among the available flower heads. Our results indirectly indicate the existence of an oviposition-deterring pheromone (ODP) in P. teleius. This hypothetical marking ensures a more even distribution of eggs and possibly increases the chances of survival of caterpillars by reducing competition during both the phytophagous and myrmecophagous stages of development. There are few reports of butterflies producing ODPs and to our knowledge this is the first evidence of their presence in the family Lycaenidae., Marcin Sielezniew, Anna M. Stankiewicz-Fiedurek., and Obsahuje seznam literatury