Lo Zelus renardii (Kolenati, 1857) (Heteroptera Reduviidae): un promettente predatore della Macrohomotoma gladiata (Kuwayama, 1908) (Psylloidea Homotomidae) sui Ficus microcarpa Hort. Berol. ex Walp. (Moraceae) ornamentali del verde urbano a Bari
Most applications of the extreme value theory have assumed stationarity, i.e. that the statistica... more Most applications of the extreme value theory have assumed stationarity, i.e. that the statistical properties of the process do not change over time. However, there is evidence suggesting that the occurrence of extreme events is not stationary but changes naturally, as it has been found for many other climate variables. Of paramount importance for hazard analysis is whether the observed precipitation time series exhibit long-term trends or cycles; such information is also relevant in climate change studies. In this study the theory of non-stationary extreme value analysis was applied to data series of daily precipitation using the peaks-over-threshold approach. A Poisson/Generalized Pareto model, in which the model parameters were allowed to vary linearly with time, was fitted to the resulting series of precipitation event's intensity and magnitude. A log-likelihood ratio test was applied to determine the existence of trends in the model parameters. The method was applied to a case study in northeast Spain, comprising a set of 64 daily rainfall series from 1930 to 2006. Statistical significance was achieved in less than 5% of the stations using a linear non-stationary model at the annual scale, indicating that there is no evidence of a generalised trend in extreme precipitation in the study area. At the seasonal scale, however, a significant number of stations along the Mediterranean (Catalonia region) showed a significant decrease of extreme rainfall intensity in winter, while experiencing an increase in spring.
The recent introduction of orange spiny whitefly (OSW), Aleurocanthus spiniferus (Quaintance) (He... more The recent introduction of orange spiny whitefly (OSW), Aleurocanthus spiniferus (Quaintance) (Hemiptera Aleyrodidae), in Italy is a new challenge for whoever is involved in citrus producing chain activity. A.spiniferus is a polyphagous insect, reported to infest 90 plant species of 38 plant families and it is considered as one of the most destructive Citrus whiteflies worldwide. It causes a general weakening of the infested trees due to sap loss and sooty mould blackening. In Italy, A. spiniferus diffusion from its primary detection sites has been monitored, with a special focus on population density and eventual new host plant species. Up to the end of 2012, the pest was found in Lecce district only; but more recently (till April 2014) it has been collected in both Taranto and Bari districts. These findings are isolated from the original infested areas in Italy and far northern from them. Moreover, these recent collections demonstrate the OSW ability to overwinter in the new north...
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture, 2015
The presence of Aleurocanthusspiniferusis reported in Apulia from April 2008. This polyphagous wh... more The presence of Aleurocanthusspiniferusis reported in Apulia from April 2008. This polyphagous whitefly is now spreading northward and invading new territories.This paper refers about recently occupied areas detailing local and urban outbreaks and population density per host plant species.We use digital camera-equipped stereoscope and Cryo-SEM on the laboratory and direct observation on the field.We note the presence of A. Spiniferus in Puglia region and we depict the invasion of agricultural and urban areas.The overall behaviour and ecological preferences of the alien pest are discussed in view of its available means of control.
The recent introduction of orange spiny whitefly (OSW), Aleurocanthus spiniferus (Quaintance) (He... more The recent introduction of orange spiny whitefly (OSW), Aleurocanthus spiniferus (Quaintance) (Hemiptera Aleyrodidae), in Italy is a new challenge for whoever is involved in citrus producing chain activity. A.spiniferus is a polyphagous insect, reported to infest 90 plant species of 38 plant families and it is considered as one of the most destructive Citrus whiteflies worldwide. It causes a general weakening of the infested trees due to sap loss and sooty mould blackening. In Italy, A. spiniferus diffusion from its primary detection sites has been monitored, with a special focus on population density and eventual new host plant species. Up to the end of 2012, the pest was found in Lecce district only; but more recently (till April 2014) it has been collected in both Taranto and Bari districts. These findings are isolated from the original infested areas in Italy and far northern from them. Moreover, these recent collections demonstrate the OSW ability to overwinter in the new north...
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Papers by AHMED ELKENAWY