Effects of practical impairments on cooperative distributed antennas combined with fractional frequency reuse

Cooperative Multiple Point (CoMP) transmission aided Distributed Antenna Systems (DAS) are proposed for increasing the received Signal-to-Interference-plus-Noise-Ratio (SINR) in the cell-edge area of a cellular system employing Fractional Frequency Reuse (FFR) in the presence of realistic imperfect Channel State Information (CSI) as well as synchronisation errors between the transmitters and the receivers. Our simulation results demonstrate that the CoMP aided DAS scenario is capable of increasing the attainable SINR by up to 3dB in the presence of a wide range of realistic imperfections

Analysis and design of distributed antenna aided twin-layer femto-and macro-cell networks relying on fractional frequency-reuse

Distributed Antenna Systems (DAS) and femtocells are capable of improving the attainable performance in the cell-edge area and in indoor residential areas, respectively. In order to achieve a high spectral efficiency, both the Distributed Antenna Elements (DAEs) and Femtocell Base Stations (FBSs) may have to reuse the spectrum of the macrocellular network. As a result, the performance of both outdoor macrocell users and indoor femtocell users suffers from Co-Channel Interference (CCI). Hence in this paper, heterogenous celluar networks are investigated, where the DAS-aided macrocels and femtocells co-exist within the same area

Biology, physiology and gene expression of grasshopper Oedaleus asiaticus exposed to diet stress from plant secondary compounds

This study was supported by the National Natural Science Foundation of China, 31672485, the Earmarked Fund for China Agriculture Research System, CARS-35-07, and the Innovation Project of Chinese Academy of Agricultural Science.We studied the role of plant primary and secondary metabolites in mediating plant-insect interactions by conducting a no-choice single-plant species field experiment to compare the suitability, enzyme activities, and gene expression of Oedaleus asiaticus grasshoppers feeding on four host and non-host plants with different chemical traits. O. asiaticus growth showed a positive relationship to food nutrition content and a negative relationship to secondary compounds content. Grasshopper amylase, chymotrypsin, and lipase activities were positively related to food starch, crude protein, and lipid content, respectively. Activity of cytochrome P450s, glutathione-S-transferase, and carboxylesterase were positively related to levels of secondary plant compounds. Gene expression of UDP-glucuronosyltransferase 2C1, cytochrome P450 6K1 were also positively related to secondary compounds content in the diet. Grasshoppers feeding on Artemisia frigida, a species with low nutrient content and a high level of secondary compounds, had reduced growth and digestive enzyme activity. They also had higher detoxification enzyme activity and gene expression compared to grasshoppers feeding on the grasses Cleistogenes squarrosa, Leymus chinensis, or Stipa krylovii. These results illustrated Oedaleus asiaticus adaptive responses to diet stress resulting from toxic chemicals, and support the hypothesis that nutritious food benefits insect growth, but plant secondary compounds are detrimental for insect growth.Publisher PDFPeer reviewe

Quantitative analysis of diet structure by real-time PCR, reveals different feeding patterns by two dominant grasshopper species

This study was supported by the National Natural Science Foundation of China, 31471823, the Earmarked Fund for China Agriculture Research System, CARS-35-07, and the Innovation Project of Chinese Academy of Agricultural Science.Studies on grasshopper diets have historically employed a range of methodologies, each with certain advantages and disadvantages. For example, some methodologies are qualitative instead of quantitative. Others require long experimental periods or examine population-level effects, only. In this study, we used real-time PCR to examine diets of individual grasshoppers. The method has the advantage of being both fast and quantitative. Using two grasshopper species, Oedaleus asiaticus and Dasyhippus barbipes, we designed ITS primer sequences for their three main host plants, Stipa krylovii, Leymus chinensis and Cleistogenes squarrosa and used real-time PCR method to test diet structure both qualitatively and quantitatively. The lowest detection efficiency of the three grass species was ~80% with a strong correlation between actual and PCR-measured food intake. We found that Oedaleus asiaticus maintained an unchanged diet structure across grasslands with different grass communities. By comparison, Dasyhippus barbipes changed its diet structure. These results revealed why O. asiaticus distribution is mainly confined to Stipa-dominated grassland, and D. barbipes is more widely distributed across Inner Mongolia. Overall, real-time PCR was shown to be a useful tool for investigating grasshopper diets, which in turn offers some insight into grasshopper distributions and improved pest management.Publisher PDFPeer reviewe

Large manipulative experiments revealed variations of insect abundance and trophic levels in response to the cumulative effects of sheep grazing

This study was supported by the National Natural Science Foundation of China, 31672485, the Earmarked Fund for China Agriculture Research System, CARS-34-07, and the Innovation Project of Chinese Academy of Agricultural Sciences.Livestock grazing can affect insects by altering habitat quality; however, the effects of grazing years and intensities on insect abundance and trophic level during manipulative sheep grazing are not well understood. Therefore, we investigated these effects in a large manipulative experiment from 2014 to 2016 in the eastern Eurasian steppe, China. Insect abundance decreased as sheep grazing intensities increased, with a significant cumulative effect occurring during grazing years. The largest families, Acrididae and Cicadellidae, were susceptible to sheep grazing, but Formicidae was tolerant. Trophic primary and secondary consumer insects were negatively impacted by increased grazing intensities, while secondary consumers were limited by the decreased primary consumers. Poor vegetation conditions caused by heavy sheep grazing were detrimental to the existence of Acrididae, Cicadellidae, primary and secondary consumer insects, but were beneficial to Formicidae. This study revealed variations in insect abundance and trophic level in response to continuous sheep grazing in steppe grasslands. Overall, our results indicate that continuous years of heavy- and over- sheep grazing should be eliminated. Moreover, our findings highlight the importance of more flexible sheep grazing management and will be useful for developing guidelines to optimize livestock production while maintaining species diversity and ecosystem health.Publisher PDFPeer reviewe

Molecular ecological basis of grasshopper (Oedaleus asiaticus) phenotypic plasticity under environmental selection

This research was supported by the Special Fund for Agro-scientific Research in the Public Interest (201003079), China, the earmarked fund for the China Agriculture Research System (CARS-35-07 and CARS-34-7B), the Innovation Project of the Chinese Academy of Agricultural Sciences, National Nature Science Foundation of China (31672485), and the CSC Scholarship from the China Scholarship Council. The transcriptome data of O. asiaticus females was submitted to SRA database in NCBI and have been released (ID: SRP059063).While ecological adaptation in insects can be reflected by plasticity of phenotype, determining the causes and molecular mechanisms for phenotypic plasticity (PP) remains a crucial and still difficult question in ecology, especially where control of insect pests is involved. Oedaleus asiaticus is one of the most dominant pests in the Inner Mongolia steppe and represents an excellent system to study phenotypic plasticity. To better understand ecological factors affecting grasshopper phenotypic plasticity and its molecular control, we conducted a full transcriptional screening of O. asiaticus grasshoppers reared in four different grassland patches in Inner Mongolia. Grasshoppers showed different degrees of PP associated with unique gene expressions and different habitat plant community compositions. Grasshopper performance variables were susceptible to habitat environment conditions and closely associated with plant architectures. Intriguingly, eco-transcriptome analysis revealed five potential candidate genes playing important roles in grasshopper performance, with gene expression closely relating to PP and plant community factors. By linking the grasshopper performances to gene profiles and ecological factors using canonical regression, we first demonstrated the eco-transcriptomic architecture of grasshopper phenotypic traits. Regression biplot revealed plant food type, plant density, coverage, and height were the main ecological factors influencing PP, while insect cuticle protein (ICP), negative elongation factor A (NELFA), and lactase-phlorizin hydrolase (LCT) were the key genes associated with PP. Our study gives a clear picture of gene-environment interaction in the formation and maintenance of PP and enriches our understanding of the transcriptional events underlying molecular control of rapid phenotypic plasticity associated with environmental variability. The findings of this study may also provide new targets for pest control and highlight the significance of ecological management practice on grassland conservation.Publisher PDFPeer reviewe

A Novel Wireless Sensor Network Node Localization Algorithm Based on BP Neural Network

The accurate localization of wireless sensor network node is one of the supporting technologies of network application. A novel localization algorithm of wireless sensor network node based on BP neural network is put forward in the paper. This localization algorithm constructs the BP neutral network model in accordance with the number of the anchor node firstly, and then trains the network by the anchor node and estimates the location of the unknown node. Moreover, the virtual anchor node is introduced into this algorithm in order to realize its optimization, which increases the anchor node scale in the network and improves the localization accuracy of the node. The simulation experiment results in two different conditions show that compared with Centroid algorithm and DV-Hop algorithm, the localization algorithm of this paper estimates the location of the unknown node more precisely and improves the location accuracy more effectively. This algorithm demonstrates its merits greatly

Vibronic fine structure in the nitrogen 1s photoelectron spectra from Franck-Condon simulations II: Indoles

The vibronic coupling effect in nitrogen 1s X-ray photoelectron spectra (XPS) was systematically studied for a family of 17 bicyclic indole molecules by combining Franck-Condon simulations (including the Duschinsky rotation effect) and density functional theory. The simulated vibrationally-resolved spectra of 4 molecules agree well with available experiments. Reliable predictions for this family further allowed us to summarize rules for spectral evolution in response to three types of common structural changes (side chain substitution, CH$\leftrightarrow$N replacement, and isomerization). Interestingly, vibronic properties of amine and imine nitrogen are clearly separated: they show negative and positive $\Delta$ZPE (zero-point vibration energy of the core-ionized with respect to the ground state), respectively, indicating flatter and steeper PESs induced by the N 1s ionization; amine N's show stronger mode mixing effects than imine N's; the 1s ionizations on two types of nitrogens led to distinct changes in local bond lengths and angles. The rules are useful for a basic understanding of vibronic coupling in this family, and the precise spectra are useful for future reference and data mining studies