Optimal Diversity Research Articles

Aspergillus flavus pangenome (AflaPan) uncovers novel aflatoxin and secondary metabolite associated gene clusters

BackgroundAspergillus flavus is an important agricultural and food safety threat due to its production of carcinogenic aflatoxins. It has high level of genetic diversity that is adapted to various environments. Recently, we reported two reference genomes of A. flavus isolates, AF13 (MAT1-2 and highly aflatoxigenic isolate) and NRRL3357 (MAT1-1 and moderate aflatoxin producer). Where, an insertion of 310 kb in AF13 included an aflatoxin producing gene bZIP transcription factor, named atfC. Observations of significant genomic variants between these isolates of contrasting phenotypes prompted an investigation into variation among other agricultural isolates of A. flavus with the goal of discovering novel genes potentially associated with aflatoxin production regulation. Present study was designed with three main objectives: (1) collection of large number of A. flavus isolates from diverse sources including maize plants and field soils; (2) whole genome sequencing of collected isolates and development of a pangenome; and (3) pangenome-wide association study (Pan-GWAS) to identify novel secondary metabolite cluster genes.ResultsPangenome analysis of 346 A. flavus isolates identified a total of 17,855 unique orthologous gene clusters, with mere 41% (7,315) core genes and 59% (10,540) accessory genes indicating accumulation of high genomic diversity during domestication. 5,994 orthologous gene clusters in accessory genome not annotated in either the A. flavus AF13 or NRRL3357 reference genomes. Pan-genome wide association analysis of the genomic variations identified 391 significant associated pan-genes associated with aflatoxin production. Interestingly, most of the significantly associated pan-genes (94%; 369 associations) belonged to accessory genome indicating that genome expansion has resulted in the incorporation of new genes associated with aflatoxin and other secondary metabolites.ConclusionIn summary, this study provides complete pangenome framework for the species of Aspergillus flavus along with associated genes for pathogen survival and aflatoxin production. The large accessory genome indicated large genome diversity in the species A. flavus, however AflaPan is a closed pangenome represents optimum diversity of species A. flavus. Most importantly, the newly identified aflatoxin producing gene clusters will be a new source for seeking aflatoxin mitigation strategies and needs new attention in research.

A parallel particle swarm optimization and enhanced sparrow search algorithm for unmanned aerial vehicle path planning

Unmanned Aerial Vehicle (UAV) path planning is to plan an optimal path for its flight in a specific environment. But it cannot get satisfactory results using ordinary algorithms. To solve this problem, a hybrid algorithm is proposed named as PESSA, where particle swarm optimization (PSO) and an enhanced sparrow search algorithm (ESSA) work in parallel. In the ESSA, the random jump of the producer’s position is strengthened to guarantee the global search ability. Each scrounger keeps learning from the vintage experience of the producers. For the best-positioned sparrow, when it perceives the threat, the difference between the best individual and the worst individual will be imposed to speed up the search process. The elite reverse search strategy was added to yields the optimum diversity. In this paper, the performance of the PESSA algorithm is verified by 10 basic functions, and it can find the optimal value on the 7 test functions. Compared with the other 12 algorithms, PESSA’s average value always ranks first. Finally, the proposed PESSA is applied in 4 different scenarios including two groups of 2D environments and two groups of 3D environments. In 2D environments, the average optimization results can reach 0.0165 and 0.0521 in two cases respectively. In 3D environments, the average optimization results can reach 0.6635 and 0.5349 in two cases respectively. The results show that the PESSA algorithm can acquire more feasible and effective route than compared algorithms.

Three-dimensional numerical study for determining the optimum diversion angle of bifurcating channels

Water diversion to bifurcating canals has been attracting interest from water engineering researchers for decades. It can be described by the size of the separation zone in the intake channel and the quantity of flow rate into the bifurcating channel based on the diversion angle. The present study is an attempt to determine the optimum diversion angle of bifurcating channels that can achieve the minimum separation zone size in the intake channel and maximum discharge in the bifurcating channel. The study’s objectives were achieved by using the theoretical three-dimensional (3D) ANSYS 16 software to investigate the diverted flow into bifurcating channels with different diversion angles (90, 75, 60, 45, 30, and 15-degrees). Theoretical expected flow characteristics have been validated by experimental work. According to the findings, the ANSYS 16 software is a good tool for calculating bifurcating channel flow patterns. The final results proved that the 15-degree diversion angle has the optimum impact on the diverted flow. In addition, it achieves a maximum flow rate in the bifurcating channel (about 8.1 L/s), which represents nearly 49.4% of the main channel flow. It also provides a negligible separation zone with respect to the other diversion angles of the bifurcating channel. As a result, the efficiency of distributing, transporting, and controlling the limited amount of water available will improve.

Genetic diversity analysis of maintainer lines using SSR markers in rice (Oryza sativa L.)

Hybrid breeding technology is one of the most feasible options to meet the future food challenges and sustainable agriculture. Genetic diversity studies determine the inherent potential of a cross for heterosis and frequency of desirable recombinants. Optimum parental diversity is required to obtain superior cross combinations in the further generations. Hence, the present study was conducted with 100 maintainer lines of rice hybrids using eighty SSR markers, out of which 16 were found to be polymorphic and 10 were monomorphic. Molecular diversity analysis revealed a total of five clusters at a similarity coefficient 0.73. Sixteen out of 80 markers were found to be polymorphic. The number of alleles per locus ranged from 2 to 8 with an average per locus of 4.5. The PIC values varied widely among SSR loci tested and ranged from a minimum 0.37 (JGT725.2) to maximum 0.76 (RM12424) with an average of 0.61. The highest similarity was observed between TCP 1128 and TCP 1145 whereas the most diverse genotypes were TCP726 and TCP816. The most diverse genotypes could be used as parents in the hybridization experiments.

Genetic characterization and diversity assessment in ‘Bhangor’ indigenous swamp buffalo population using heterologous microsatellite markers

‘Bhangor’ newly identified swamp buffalo population from North East Indian, was characterized using microsatellite markers. Genomic DNA was isolated from blood samples of 76 unrelated animals, 15 microsatellite markers (CSSM33, BM1818, CSRM60, HEL13, ILSTS019, ILSTS025, ILSTS028, ILSTS029, ILSTS033, ILSTS036, ILSTS056, ILSTS058, ILSTS061, ILSTS089 and ETH003) were found to be highly polymorphic in the population of the selected markers. A total of 114 alleles were observed, which ranged from 3 in CSRM60 and ILSTS025 locus to 12 in ILSTS056 and ILSTS061. The mean effective number of alleles across all polymorphic loci was found to be 3.76. The overall mean expected heterozygosity and unbiased expected heterozygosity values were 0.67 and 0.68, ranging from 0.067 (ILSTS025) to 0.85 (ILSTS058) and 0.068 (ILSTS025) to 0.86 (ILSTS058), respectively. Within the population, the inbreeding estimates (FIS) ranged between −0.4352 and 0.804, with an average FIS of 0.114 ± 0.033. The outcome for infinite allele model (IAM), two-phase model (TPM) and test for mode shift revealed the absence of any recent bottleneck in the investigated buffalo population. The population was found to be in optimum diversity based on polymorphic microsatellite markers. With fast changing agro-climatic conditions; there is an urgent need to characterize the nondescript livestock populations.

Aboveground Biomass of Living Trees Depends on Topographic Conditions and Tree Diversity in Temperate Montane Forests from the Slătioara-Rarău Area (Romania)

The study zone includes one of the largest montane old-growth forests in Europe (Slatioara UNESCO site), and understanding the structure and functioning of sill intact forests in Europe is essential for grounding management strategies for secondary forests. For this reason, we set out to analyze the dependencies between aboveground biomass (AgB), tree species and size diversity and terrain morphology, as well as the relationship between biomass and diversity, since neither of these issues have been sufficiently explored. We found that tree species diversity decreases with increased solar radiation and elevation. Tree size heterogeneity reaches its highest mean values at elevations between 1001 and 1100 m, on slopes between 50 and 60 degrees. AgB is differentiated with elevation; the highest mean AgB (293 tonnes per hectare) is recorded at elevations between 801 and 900 m, while it decreases to 79 tonnes per hectare at more than 1500 m a.s.l. It is also influenced by tree species diversity and tree size heterogeneity, with the highest AgB reached in the most complex forest ecosystems in terms of structural diversity. We showed that intact temperate montane forests develop maximum biomass for optimum species diversity and highest size heterogeneity; all three are modulated mainly by elevation.

Forest Transformation Urgency for Topsoil Diversity Optimization During Environmental Change

Abstract Combined effect of environmental change and management variability leads to reduced soil diversity in homogenous forest stands. On the other hand, forest soil diversity is maintained with rich tree species composition. In this study, focus has been put on deriving urgency to change forest tree species composition in order to increase soil diversity in biogeographic regions with uneven impact of environmental change. The relation of forest tree species and soil diversities was compared between the periods of dominant sulphur deposition (1985–1994) and the period of regional environmental change (2003–2012) in the Czech Republic (Central Europe; 78 866 km2; 115–1602 m n.m.). Forest tree species and soil diversities were assessed using linear regression, discrimination analysis and geographically weighted regression including residue analysis. The effect of spatial differences of acid deposition on soil properties, though, decreased, still dependencies between the diversity of bedrock, soils and forest tree species increased significantly. Only 12.9 % of forests in the territory of the CR have optimum tree species diversity. The total of 65.9 % of forest require highly or moderately urgent transformation. An increase in spatial dependencies between soil and tree species diversities confirms the importance of site differentiation in forest transformation.

Long-term outcome of transplant ureterostomy in children: A National Review.

CAKUT are the most common cause of end-stage renal failure in children (Pediatr Nephrol. 24, 2009, 1719). Many children with CAKUT have poor urinary drainage which can compromise post-transplant outcome. Identifying safe ways to manage anatomical abnormalities and provide effective urinary drainage is key to transplant success. Much debate exists regarding optimum urinary diversion techniques. The definitive formation of a continent urinary diversion is always preferable but may not always be possible. We explore the role of ureterostomy formation at transplantation in a complex pediatric group. We report six pediatric patients who had ureterostomy formation at the time of transplantation at the National Paediatric Transplant Centre in Dublin, Ireland. We compared renal function and burden of urinary tract infection to a group with alternative urinary diversion procedures and a group with normal bladders over a 5-year period. There was no demonstrable difference in estimated glomerular filtration rate between the groups at 5-year follow-up. The overall burden of UTI was low and similar in frequency between the three groups. Ureterostomy formation is a safe and effective option for temporary urinary diversion in children with complex abdominal anatomy facilitating transplantation; it is, however, important to consider the implications and risk of ureterostomy for definitive surgery after transplantation.

Reducing the Non-Recurrent Freeway Congestion with Detour Operations: Case Study in Florida

To alleviate the impacts of freeway incidents and improve the traffic conditions on the entire transportation network, operational systems of discrete facilities need to be coordinated on a corridor. As such, this study focuses on a new traffic diversion methodology for a better utilization of the available traffic capacity of the corridor. The methodology aims to divert incident-induced freeway congestion to the adjacent arterials using the VISSIM microsimulation tool, which can simulate a freeway incident and measure the performance of detour operations. Within the study, an experiment with a 23 full factorial central composite design is utilized in order to define the optimum diversion rate in different demand levels. Experimental results are also modeled with the hierarchical multilevel regression model. Findings indicate that the resultant regression equation can successfully predict the corridor delay with 7 (s/veh) error and 83.85% accuracy. Traffic agencies can employ the proposed hierarchical model to decide whether or not a detour should be implemented. Furthermore, with the estimate of the incident duration and the current V/C ratio on the freeway, the diversion rate that results in a minimum corridor delay can be identified.

Near-Field Cross-Correlation Analysis for MIMO Wireless Communications

We propose a source-based approach to the analysis and evaluation of cross correlation in generic near-field (NF) interaction scenarios. The proposed theory integrates electromagnetics and stochastic considerations to derive a general formula for Rx port-to-port cross correlation. The derivation is quite general and is expressed in terms of the stochastic correlation tensor of arbitrary random NF source cloud close to the Rx multiple-input-multiple-output (MIMO) antenna terminals. The theory is then simplified by computing the response to a random NF point source, allowing fast and efficient computations when the NF source is replaced by an equivalent infinitesimal dipole model. The resulted formula is then exploited to devise a new cross-correlation performance evaluation metric suitable for the design of optimum NF spatial diversity applications antennas. The proposed approach and performance evaluation metric are anticipated to play a direct role in NF communication systems antenna design in particular, and stochastic electromagnetics in general.

Genetic characterization and assessment of diversity in Pandharpuri buffalo breed of India using heterologous microsatellite markers

The present study was aimed at genetic characterization and diversity analysis of Pandharpuri buffalo population using the Food and Agriculture Organization (FAO) recommended bovine microsatellite markers. Genomic DNA was isolated from blood samples of 50 unrelated animals and a total of 23 microsatellite loci were amplified using polymerase chain reaction. Among 23 recommended microsatellite markers, 14 markers (BM2113, BM1818, CSSM66, HEL13, INRA037, ILSTS05, HAUT27, INRA023, INRA035, HEL5, ETH3, NRA063, MM12 and ETH10) were found to be highly polymorphic in Pandharpuri population. The amplified products were run on polyacrylamide gel electrophoresis (PAGE) apparatus along with a ladder; subsequently, the allele typing was done based on silver staining of the gel. The effective and observed number of alleles, heterozygosity (expected and unbiased) estimates and polymorphic information content (PIC) levels were estimated for each locus. A total of 87 alleles were secured for 14 polymorphic loci studied giving an overall average of 6.21 alleles per locus. The number of alleles ranged from 2 (INRA063) to 9 (BM1818 and HEL13). The mean effective number of alleles across all polymorphic loci was found to be 4.28. The overall mean expected heterozygosity and unbiased expected heterozygosity values were 0.77 and 0.76, ranging from 0.50 (INRA063) to 0.88 (BM1818) and 0.50 (INRA063) to 0.88 (BM1818), respectively. The average PIC estimate across all polymorphic loci was 0.73 ranging from 0.373 (INRA063) to 0.864 (BM1818). In the present study, the characterization and diversity estimates are reported for Pandharpuri population. It was found to maintain optimum diversity based on 14 polymorphic microsatellite markers.

Optimization and Effect of Inner Water Diversion and Distribution in the West Lake of Hangzhou

West Lake is a world-famous landscape in Hangzhou, listed on the World Heritage list. In 2003, Hangzhou municipal government implemented the project of water diversion project, which diverted 400,000t/d water from Qiantang River into West Lake, thus, improved the overall water quality of West Lake significantly. However, due to the zigzag lakeshore line and the inlake embankment separation, the diverted water could not fully exchange among different regions of the lake, therefore, high concentration region of nutrient and cyanobacteria outbreak risk still existed in some lake bays. On the basis of spatial water quality analysis, this study put forward the internal water diversion and distribution scheme of the West Lake. Total phosphorus (TP) model with Environmental Fluid Dynamic Code (EFDC) was built to study the optimum water diversion quantity and distribution layout. According to the numerical result, the recommended water diversion scale was 70,000t/d, the layout of diversion and distribution recommended was “2 in 3 out”. The internal water diversion and distribution project was complemented in October 2015. According to the comparison of water quality before and after the project construction, the improvement rates of TP, TN and Chlorophyll A were 26.0%, 8.9% and 25.9% respectively, and the dead water area was reduced from 35% to 13%, which greatly improved the water environment of the water diversion area.

Biochar Effects on Bacterial Community and Metabolic Pathways in Continuously Cotton-Cropped Soil

This study was purposely designed to understand the role of biochar in soil bacterial community structure and diversity over continuous cotton-cropping years. The research questions addressed were what was the bacterial taxonomic status, the microbial community diversity and the cluster distribution and prediction of microbial metabolic functions across the continuous cotton-cropping years (5, 10, 20, and 40 years) under different biochar treatment rates (0 t ha-1, 20 t ha−1, and 40 t ha−1)? High-throughput sequencing of the 16S and integrated bioinformatic analysis techniques was used. The result showed that biochar of 20 t ha−1 and 40 t ha−1 application rate of up to 20 years of continuously cotton-cropped soils significantly increased bacterial diversity. However, higher application rates of up to 40 years on continuously cropped soils did not significantly change bacterial diversity and richness as compared to the 20 years of continuously cropped soil. The study also established the optimum bacterial diversity to be at 20 years of continuous cotton cropping, and the value were highest at 20 t ha−1 and 40 t ha−1 of biochar application rates. In contrast to the 20 years of continuous biochar application in cropped soils, higher application rates of up to 40 years on continuously cropped soils did not significantly change bacterial diversity and richness. In conclusion, controlled biochar application positively influences soil bacterial community and metabolic pathways in continuously cropped cotton soils. This indicates the significance of biochar application under different years of continuous cotton cropping on soil bacterial community structure, diversity, cluster distribution, and metabolic functions.

Invited review: Microbiota of the bovine udder: Contributing factors and potential implications for udder health and mastitis susceptibility

Various body sites of vertebrates provide stable and nutrient-rich ecosystems for a diverse range of commensal, opportunistic, and pathogenic microorganisms to thrive. The collective genomes of these microbial symbionts (the microbiome) provide host animals with several advantages, including metabolism of indigestible carbohydrates, biosynthesis of vitamins, and modulation of innate and adaptive immune systems. In the context of the bovine udder, however, the relationship between cow and microbes has been traditionally viewed strictly from the perspective of host-pathogen interactions, with intramammary infections by mastitis pathogens triggering inflammatory responses (i.e., mastitis) that are often detrimental to mammary tissues and cow physiology. This traditional view has been challenged by recent metagenomic studies indicating that mammary secretions of clinically healthy quarters can harbor genomic markers of diverse bacterial groups, the vast majority of which have not been associated with mastitis. These observations have given rise to the concept of "commensal mammary microbiota," the ecological properties of which can have important implications for understanding the pathogenesis of mastitis and offer opportunities for development of novel prophylactic or therapeutic products (or both) as alternatives to antimicrobials. Studies conducted to date have suggested that an optimum diversity of mammary microbiota is associated with immune homeostasis, whereas the microbiota of mastitic quarters, or those with a history of mastitis, are considerably less diverse. Whether disruption of the diversity of udder microbiota (dysbiosis) has a role in determining mastitis susceptibility remains unknown. Moreover, little is known about contributions of various biotic and abiotic factors in shaping overall diversity of udder microbiota. This review summarizes current understanding of the microbiota within various niches of the udder and highlights the need to view the microbiota of the teat apex, teat canal, and mammary secretions as interconnected niches of a highly dynamic microbial ecosystem. In addition, host-associated factors, including physiological and anatomical parameters, as well as genetic traits that may affect the udder microbiota are briefly discussed. Finally, current understanding of the effect of antimicrobials on the composition of intramammary microbiota is discussed, highlighting the resilience of udder microbiota to exogenous perturbants.

Dietary diversity and associated factors among children aged 6\u201323 months in Sinan Woreda, Northwest Ethiopia: a cross-sectional study

BackgroundChild malnutrition accounted by poor dietary diversity is common in developing countries contributing for child morbidity and mortality. It also has an impact on child growth and development. Almost all nutritional related problems are preventable by implementing infant and child feeding strategies. The first two years of life are particularly important to reverse the nutritional problems by achieving dietary diversity feeding.The study aimed to assess dietary diversity and its associated factors among 6–23 months old children in Sinan Woreda, Northwest Ethiopia.MethodsWe conducted community based cross-sectional study among children aged 6–23 months in Sinan Woreda from February 16 to March 10, 2016. Random sampling technique was used to select 740 samples. Data on children’s dietary diversity of the last 24 h were collected through interview of mothers. Data were entered into EpiData version 3.1 and analysis was performed using SPSS version 20. The bivariate and multivariable logistic regression analyses were done to identify the independent factors associated with sub-optimal dietary diversity among children aged 6–23 months.ResultsSeven hundred thirty six samples were included in the analysis with the response rate of 99%. Optimum dietary diversity was observed in 13% children. The dominant food groups consumed were grains. Availability of media sources at household [Adjusted Odds Ratio (AOR) = 2.77 (1.65–4.68)], availability of cow milk in the household [AOR = 2.39 (1.31–4.35)], women’s involvement in decision-making at household level [AOR = 2.07 (1.02–4.20)], institutional delivery service utilization [AOR = 2.40 (1.24–4.67)], receiving assisted delivery service [AOR = 2.36 (1.12–4.98)], receiving postnatal care [AOR = 2.07 (1.18–3.63)], distance far from the health center [AOR = 3.11 (1.66–5.83)] and meal frequency being four and above [AOR = 3.31 (1.53–7.18)] were associated with dietary diversity.ConclusionThis study concluded that optimum dietary diversity among children aged 6–23 months in Sinan Woreda is low. Meal frequency is positively associated with dietary diversity. Women involvement at household decision making improves dietary diversity of children. Ensuring maternal health service utilization can contribute for better dietary diversity of children aged 6–23 months. Large scale an interventional based research has to be conducted.

Empirical Geometrical Bounds on MIMO Antenna Arrays for Optimum Diversity Gain Performance: An Electromagnetic Design Approach

We propose a general design methodology for synthesizing surface or volume multi-input-multi-output (MIMO) antenna arrays with optimum cross-correlation diversity gain performance through engineering the array’s geometrical shape. The design algorithm is based on approximating arbitrary antenna geometrical configurations by the arrays of infinitesimal (electrically small) dipoles and then using the recently introduced cross-correlation Green’s function in order to compute far-field cross correlations without the need to explicitly measure or compute far-zone fields. After directly expressing far-field cross correlation in terms of the geometrical details of the antenna array (position and orientation), the method applies a global optimization strategy (the genetic algorithm) to find optimum positions and orientations of the MIMO antennas’ elements within a given geometrical shape, resulting in the statistically best system performance. We provide extensive numerical results, including various array topologies (both fixed and conformal), with investigations of the impact of the array density, positions, and the relative orientations of the composing antenna elements on the attainable diversity gain. This paper also outlines an expansion of the proposed design methodology in order to deal with the important special case when a ground plane is present in the MIMO environment. It is found using the proposed methods that small MIMO receiver terminals can be made to fit any geometrical shape by properly controlling the position and the orientation of each element. All the resulting arrays have dimensions that are smaller than $0.35\lambda \times 0.35\lambda$ with the diversity gain of 80% or greater. It was also found that for each antenna topology, a critical number of antennas per unit area/volume exist, such that no further improvement of the diversity gain is possible. This upper bound is geometrical in nature, but it is obtained through an electromagnetic analysis, clearly demonstrating the impact of relative antenna positioning and orientations. Various 2-D and 3-D antenna array configurations, including disk, ring, spheres, and spherical layers, were investigated and their critical array densities are tabulated. Also, a practical example of conformal arrays mounted on an avionic nose was provided. It was also found that relative orientations alone can be exploited to substantially improve the performance of MIMO arrays by considering different scenarios comparing position-alone, orientation-alone, and position-and-orientation optimization processes with random arrays in terms of diversity gain performance. The method developed in this paper can be expanded to include more complex antenna types, but it is also suitable for scalable computing analysis of continuous large radiating and receiving antenna surfaces and massive MIMO. In particular, for mmWave applications, we expect that the need to optimize large arrays of tiny antennas will increase the demand for accurate and general design algorithms, such as the one proposed in this paper.

Bit error rate performance of IR‐UWB ED‐PPM system using cooperative dual‐hop AF strategy

This study presents a novel analytical approach for evaluation of bit error rate (BER) performance of an impulse radio-ultra-wideband (IR-UWB) energy detector-pulse position modulation (ED-PPM) system, using dual-hop cooperative amplify and forward (AF) relaying strategy with optimum diversity combining, over IEEE 802.15.4a UWB channel. An approximate expression for BER has been derived based on energy detection principle. The analytical BER expression thus derived is validated with computer simulations, which confirm the accuracy in approximation used in investigation of BER. Furthermore, it is observed that the BER performance of IR-UWB ED-PPM system, improves substantially using dual-hop cooperative AF scheme, compared with non-cooperative scheme. Despite its poor BER performance, ED systems are preferred over AC systems, because of simplicity and low complexity.

High Mobility Wireless Communications With Doppler Diversity: Fundamental Performance Limits

The objective of this paper is to quantify the fundamental tradeoff between Doppler diversity and channel estimation errors in high mobility systems. Fast fading variation in high mobility systems introduces Doppler diversity that can benefit system performance. On the other hand, it is more difficult to estimate and track a fast changing channel, thus channel estimation errors are non-negligible and they may seriously degrade system performance. Such a tradeoff relationship is studied by identifying the exact analytical expressions of two performance metrics: the maximum Doppler diversity order achievable with imperfect channel state information (CSI), and the loss in signal-to-noise ratio (SNR) caused by channel estimation errors. The analytical study is enabled by a simple repetition code at the transmitter, and a new optimum diversity receiver developed by analyzing the statistical properties of channel estimation errors. With the analytical results, the optimum allocation of transmission energy between pilot symbols and data symbols are obtained to simultaneously maximize the Doppler diversity order and minimize the SNR loss, thus achieve the optimum tradeoff between the two. The results reveal the fundamental performance limits of Doppler diversity systems operating in the presence of imperfect CSI, and they can be used to guide the design of practical systems.

Harmonious Allocation Model of the River Diversion Standard under Synchronous Construction of Hydropower Stations

It is incapable for current method to establish the diversion standard when two hydropower stations are constructed synchronously. Hence this paper studied it from the perspective of harmonious allocation with considering the balance between economy and safety. Firstly, the risk estimation model of each diversion system under such condition was established in which the composition theory of regional flood was introduced to calculate the changed flood and the Copula function was adopted to construct its probability distribution. On this basis, with treating the adjacent diversion system as a whole, the allocation model of the diversion standard was established in which the life cycle cost (LCC) was proposed as the evaluation index. Aimed at the minimum of the LCC of the serial diversion system, the optimum diversion standard combination was ascertained. Finally, an engineering case was presented to validate the feasibility and effectiveness of the proposed model. And the study can offer the theoretical basis and technical reference for the control of the construction flood in the development of the cascade hydropower station.

Application of the CWQII method and a 2D water quality model to assess diversion schemes for East Lake (Donghu), Wuhan, China

The water quality of East Lake, the largest urban lake in China, has continuously deteriorated as a result of urban development. To improve the lake's water quality, a diversion construction project is underway to divert water from the Yangtze River to the lake to accelerate the flow cycle and decrease nutrient concentrations. This study assessed the effects of proposed diversion schemes on water quality using the composite water quality identification index (CWQII) method and a 2-dimensional (2D) water quality model. The study results indicated that the water quality of the lake is strongly influenced by diversion schemes, including diverting locations, discharge, and time. The optimum diversion inlet was inlet 2 (located in Shuiguo Bay), and the most efficient discharge was 30 m3/s. Diverting from different inlet locations caused more obvious reduction rates of CWQII in summer (Jul) than in winter (Jan). After diversion, CWQII values throughout the entire lake were reduced, and the spatial distribution of CWQII became more homogeneous. The highest reduction of CWQII occurred near the inlet location. The CWQII method and 2D water quality model provided a relevant example for assessing the general water quality and designing optimal schemes for diversion projects to improve water quality in large shallow lakes.