Differential Spatial Gradients of Wheat Streak Mosaic Virus into Winter Wheat from a Central Mite-Virus Source

The wheat curl mite (WCM), Aceria tosichella Keifer, transmits three potentially devastating viruses to winter wheat. An increased understanding of mite movement and subsequent virus spread through the landscape is necessary to estimate the risk of epidemics by the virus in winter wheat. Owing to the small size of WCMs, their dispersal via wind is hard to monitor; however, the viruses they transmit produce symptoms that can be detected with remote sensing. The objective of this study was to characterize the spatial dispersal of the virus from a central mite-virus source. Virus infection gradients were measured spatially by using aerial remote sensing, ground measurements, geostatistics, and a geographic information system between 2006 and 2009. The red edge position vegetation index as measured via aerial imagery was significantly correlated with in-field biophysical measurements. The occurrence of virus symptoms extended differentially in all directions from mite-virus source plots, and predictions from cokriging revealed an oval pattern surrounding the source but displaced to the southeast. The variable dispersal in different directions appeared to be influenced by the mite source density and wind direction and speed, but temperature also seemed likely to have affected mite spread. The spatial spread revealed in this study may be used to estimate the potential sphere of influence of mite-infested volunteer wheat in production fields. These risk parameter estimates require further validation, but they may potentially aid growers in making better virus management decisions regarding differential virus spread potential away from a central source.

Study on ARP Protocol and Network Security in Digital Manufacturing

Network spoofing attacks are very specialized attacks, and network security managers brought a severe test. In this paper, through the analysis of the ARP protocol works, it discusses ARP protocol ARP virus are two common attacks from the IP address to the security risks that exist in the physical address resolution process, and then analyzes in detail, and then introduces the ARP Find virus source and virus removal methods, and finally putting forward effective measures to guard against ARP virus.

A New Virus Source Inference Model Based on Network Performance Estimation

Combining network tomography, a new virus source inference model based on network performance is proposed. Both the topology information and real time network status are considered in our model. Performance metrics are introduced into rumor-centrality-based source detecting algorithm in an active inference way. By improving the process of setting up the spanning tree of infected topology we raise the virus source inference precision and reduce the time complexity of rumor-centrality-based algorithm from O(N2(|V|+|E|)) to O(N2). The simulation results show that our model achieves better estimation accuracy than the algorithm using rumor center as the estimator.

Peste des petits ruminants in Arabian wildlife

SUMMARYRecurrence of peste des petits ruminants (PPR) was diagnosed in the United Arabian Emirates in several wild ruminants confirmed by morphological, immunohistochemical, serological and molecular findings. Phylogenetic analysis revealed that the virus strain belongs to lineage IV, which is different to some previously isolated PPR strains from the Arabian Peninsula. This study shows that wild ruminants may play an important epidemiological role as virus source for domestic small ruminants.