Learning information extraction patterns

The rapid growth of online texts call for systems that can extract relevant information. Many information extraction systems have been developed using the knowledge engineering approach, which is often time-consuming, laborious, and of no portability. A more promising direction is to apply machine learning techniques to information extraction. A complete Information Extraction (IE) system, IEPlus, has been developed for exploring various design issues. Fine-grained semantic units were defined, and a strategy for semantic resolution was proposed in IEPlus. An enhancement for rule evaluation based on case frame matching was implemented in IEPlus. A rule firing strategy was also presented in IEPlus, which prioritizes the most specific rule in terms of the number of terms matched. Experiments on the Rental Ads domain demonstrated the effectiveness of the IEPlus system. IEPlus is highly flexible resulting from its object-oriented design, and has the capability of exploring various issues in information extraction system design

Cooperative Coding and Caching for Streaming Data in Multihop Wireless Networks

This paper studies the distributed caching managements for the current flourish of the streaming applications inmultihop wirelessnetworks. Many caching managements to date use randomized network coding approach, which provides an elegant solution forubiquitous data accesses in such systems. However, the encoding, essentially a combination operation, makes the coded datadifficult to be changed. In particular, to accommodate new data, the system may have to first decode all the combined datasegments, remove some unimportant ones, and then reencode the data segments again. This procedure is clearly expensivefor continuously evolving data storage. As such, we introduce a novel Cooperative Coding and Caching (C3) scheme, whichallows decoding-free data removal through a triangle-like codeword organization. Its decoding performance is very close to theconventional network coding with only a sublinear overhead. Our scheme offers a promising solution to the caching managementfor streaming data

Behavioral evidence for a magnetic sense in the oriental armyworm, Mythimna separata

Progress has been made in understanding the mechanisms underlying directional navigation in migratory insects, yet the magnetic compass involved has not been fully elucidated. Here we developed a flight simulation system to study the flight directionality of the migratory armyworm Mythimna separata in response to magnetic fields. Armyworm moths were exposed to either a 500 nT extreme weak magnetic field, 1.8 T strong magnetic field, or a deflecting magnetic field and subjected to tethered flight trials indoors in the dark. The moths were disoriented in the extreme weak magnetic field, with flight vectors that were more dispersed (variance=0.60) than in the geomagnetic field (variance=0.32). After exposure to a 1.8 T strong magnetic field, the mean flight vectors were shifted by about 105° in comparison with those in the geomagnetic field. In the deflecting magnetic field, the flight directions varied with the direction of the magnetic field, and also pointed to the same direction of the magnetic field. In the south-north magnetic field and the east-west field, the flight angles were determined to be 98.9° and 166.3°, respectively, and formed the included angles of 12.66° or 6.19° to the corresponding magnetic direction. The armyworm moths responded to the change of the intensity and direction of magnetic fields. Such results provide initial indications of the moth reliance on a magnetic compass. The findings support the hypothesis of a magnetic sense used for flight orientation in the armyworm Mythimna separata

A cold high-pressure system over North China hinders the southward migration of Mythimna separata in autumn

Background In warm regions or seasons of the year, the planetary boundary layer is occupied by a huge variety and quantity of insects, but the southward migration of insects (in East Asia) in autumn is still poorly understood. Methods We collated daily catches of the oriental armyworm (Mythimna separata) moth from 20 searchlight traps from 2014 to 2017 in China. In order to explore the autumn migratory connectivity of M. separata in East China, we analyzed the autumn climate and simulated the autumn migration process of moths. Results The results confirmed that northward moth migration in spring and summer under the East Asian monsoon system can bring rapid population growth. However, slow southerly wind (blowing towards the north) prevailed over the major summer breeding area in North China (33°–40° N) due to a cold high-pressure system located there, and this severely disrupts the autumn ‘return’ migration of this pest. Less than 8% of moths from the summer breeding area successfully migrated back to their winter-breeding region, resulting in a sharp decline of the population abundance in autumn. As northerly winds (blowing towards the south) predominate at the eastern periphery of a high-pressure system, the westward movement of the high-pressure system leads to more northerlies over North China, increasing the numbers of moths migrating southward successfully. Therefore, an outbreak year of M. separata larvae was associated with a more westward position of the high-pressure system during the previous autumn. Conclusion These results indicate that the southward migration in autumn is crucial for sustaining pest populations of M. separata, and the position of the cold high-pressure system in September is a key environmental driver of the population size in the next year. This study indicates that the autumn migration of insects in East China is more complex than previously recognized, and that the meteorological conditions in autumn are an important driver of migratory insects’ seasonal and interannual population dynamics

Molecular Evidence for the Fitness of Cotton Aphid, Aphis gossypii in Response to Elevated CO2 From the Perspective of Feeding Behavior Analysis

Rising atmospheric carbon dioxide (CO2) concentration is likely to influence insect–plant interactions. Aphid, as a typical phloem-feeding herbivorous insect, has shown consistently more positive responses in fitness to elevated CO2 concentrations than those seen in leaf-chewing insects. But, little is known about the mechanism of this performance. In this study, the foliar soluble constituents of cotton and the life history of the cotton aphid Aphis gossypii and its mean relative growth rate (MRGR) and feeding behavior were measured, as well as the relative transcript levels of target genes related appetite, salivary proteins, molting hormone (MH), and juvenile hormone, to investigate the fitness of A. gossypii in response to elevated CO2 (800 ppm vs. 400 ppm). The results indicated that elevated CO2 significantly stimulated the increase in concentrations of soluble proteins in the leaf and sucrose in seedlings. Significant increases in adult longevity, lifespan, fecundity, and MRGR of A. gossypii were found under elevated CO2 in contrast to ambient CO2. Furthermore, the feeding behavior of A. gossypii was significantly affected by elevated CO2, including significant shortening of the time of stylet penetration to phloem position and significant decrease in the mean frequency of xylem phase. It is presumed that the fitness of A. gossypii can be enhanced, resulting from the increases in nutrient sources and potential increase in the duration of phloem ingestion under elevated CO2 in contrast to ambient CO2. In addition, the qPCR results also demonstrated that the genes related to appetite and salivary proteins were significantly upregulated, whereas, the genes related to MH were significantly downregulated under elevated CO2 in contrast to ambient CO2, this is in accordance with the performance of A. gossypii in response to elevated CO2. In conclusion, rise in atmospheric CO2 concentration can enhance the fitness of A. gossypii by increasing their ingestion of higher quantity and higher quality of host plant tissues and by simultaneously upregulating the transcript expression of the genes related to appetite and salivary proteins, and then this may increase the control risk of A. gossypii under conditions of climate change in the future

Learning information extraction patterns

The rapid growth of online texts call for systems that can extract relevant information. Many information extraction systems have been developed using the knowledge engineering approach, which is often time-consuming, laborious, and of no portability. A more promising direction is to apply machine learning techniques to information extraction. A complete Information Extraction (IE) system, IEPlus, has been developed for exploring various design issues. Fine-grained semantic units were defined, and a strategy for semantic resolution was proposed in IEPlus. An enhancement for rule evaluation based on case frame matching was implemented in IEPlus. A rule firing strategy was also presented in IEPlus, which prioritizes the most specific rule in terms of the number of terms matched. Experiments on the Rental Ads domain demonstrated the effectiveness of the IEPlus system. IEPlus is highly flexible resulting from its object-oriented design, and has the capability of exploring various issues in information extraction system design.</p

Shading Gradients Drive Differential Responses of Leaf Traits in an Early Community Germinated by Forest Topsoil

Seedling performance in the early stage is crucial to natural forest restoration, and functional traits have been widely employed in exploring plant adaptation under field conditions. However, the responses and variabilities of leaf traits have not been clearly defined at the light gradients that are used in restoration practices. We evaluated the variation in leaf treats in species and community levels in a controlled field plot with shading treatments. We found that the variation characteristics differed across different species and trait types along shading gradients. Individuals of most species had a larger leaf area (LA) and specific leaf area (SLA) in the shaded habitats, while only a few tree species showed significant responses in their leaf shape and chlorophyll concentration. Although LA and SLA showed similar directions and trends of changes in the trait mean, four response models were observed based on the light points corresponding to initial responses and following trends. The extent of within-species trait variation for each treatment was similar at the community level due to diverse changes in the direction and degrees of variation in co-occurring species. Intraspecific variation was limited within each shading treatment, while it noticeably contributed to the local adaptation in the entire heterogeneous restoration community. Our findings indicate that species with different trait combinations will have different responses to light gradients, and that the mean and degree of variation in leaf traits will also lead to distinctive strategies being created to match the different shading conditions. Vegetation restoration should consider the adaptive traits and their response diversity when selecting species and for habitat management with specific trait&ndash;environment interactions

Effects of Fertilizer Level and Intercropping Planting Pattern with Corn on the Yield-Related Traits and Insect Community of Soybean

Intercropping of corn and soybean is widely practiced in agricultural production. However, few studies have investigated the effect of intercropping and fertilizer reduction on soybean yield. In the present study, corn and soybean were interplanted in 2:2, 2:3 and 2:4 ratios. Two fertilizer levels (normal: 600 kg/ha VS. reduced: 375 kg/ha) were set. The effects of fertilizer levels and intercropping planting patterns on the growth and yield of intercropping soybeans were studied based on the changes in enzyme activities related to nitrogen metabolism and insect community in the field. The results show that fertilizer reduction significantly reduced the biomass, 100-seed weight and yield of soybean. Intercropping also reduced these yield-related traits; a decreasing trend was more obvious with a decrease in soybean ratio. Intercropping had greater effect on soybean plant biomass, 100-seed weight and yield than fertilizer reduction. Reduction in fertilizer reduced the activities of nitrogen-metabolism-related enzymes in soybean. In addition to increased NR (nitrate reductase) enzyme activity in R5, intercropping planting pattern also had negative effect on the activities of nitrogen-metabolism-related enzymes in soybean. Reduced fertilizer only significantly reduced the Pielou evenness index. Reduced fertilizer application was beneficial with respect to the outbreak of greenhouse whitefly. However, an intercropping planting pattern can significantly increase the number of species, as well as the Shannon–Wiener diversity index and the Pielou evenness index of the insect community, and significantly reduce the Simpson dominance index and the population of the important pest, green leafhopper. In conclusion, C2S4 (two corn rows with four rows of soybean) is a scientific intercropping planting pattern that can reduce the occurrence of pests through ecological regulation and does not significantly reduce the activity of enzymes-related to nitrogen metabolism in most cases, ensuring soybean yield

Influence of elevated CO2 on development and food utilization of armyworm Mythimna separata fed on transgenic Bt maize infected by nitrogen-fixing bacteria

Background Bt crops will face a new ecological risk of reduced effectiveness against target-insect pests owing to the general decrease in exogenous-toxin content in Bt crops grown under elevated carbon dioxide (CO2). The method chosen to deal with this issue may affect the sustainability of transgenic crops as an effective pest management tool, especially under future atmospheric CO2 level raising. Methods In this study, rhizobacterias, as being one potential biological regulator to enhance nitrogen utilization efficiency of crops, was selected and the effects of Bt maize (Line IE09S034 with Cry1Ie vs. its parental line of non-Bt maize Xianyu 335) infected by Azospirillum brasilense (AB) and Azotobacter chroococcum (AC) on the development and food utilization of the target Mythimna separate under ambient and double-ambient CO2 in open-top chambers from 2016 to 2017. Results The results indicated that rhizobacteria infection significantly increased the larval life-span, pupal duration, relative consumption rate and approximate digestibility of M. separata, and significantly decreased the pupation rate, pupal weight, adult longevity, fecundity, relative growth rate, efficiency of conversion of digested food and efficiency of conversion of ingested food of M. separata fed on Bt maize, while here were opposite trends in development and food utilization of M. separata fed on non-Bt maize infected with AB and AC compared with the control buffer in 2016 and 2017 regardless of CO2 level. Discussion Simultaneously, elevated CO2 and Bt maize both had negative influence on the development and food utilization of M. separata. Presumably, CO2 concentration arising in future significantly can increase their intake of food and harm to maize crop; however, Bt maize infected with rhizobacterias can reduce the field hazards from M. separata and the application of rhizobacteria infection can enhance the resistance of Bt maize against target lepidoptera pests especially under elevated CO2