Comparative study on the gut microbiotas of four economically important Asian carp species

Gut microbiota of four economically important Asian carp species (silver carp, Hypophthalmichthys molitrix; bighead carp, Hypophthalmichthys nobilis; grass carp, Ctenopharyngodon idella; common carp, Cyprinus carpio) were compared using 16S rRNA gene pyrosequencing. Analysis of more than 590,000 quality-filtered sequences obtained from the foregut, midgut and hindgut of these four carp species revealed high microbial diversity among the samples. The foregut samples of grass carp exhibited more than 1,600 operational taxonomy units (OTUs) and the highest alpha-diversity index, followed by the silver carp foregut and midgut. Proteobacteria, Firmicutes, Bacteroidetes and Fusobacteria were the predominant phyla regardless of fish species or gut type. Pairwise (weighted) UniFrac distance-based permutational multivariate analysis of variance with fish species as a factor produced significant association (P &lt; 0.01). The gut microbiotas of all four carp species harbored saccharolytic or proteolytic microbes, likely in response to the differences in their feeding habits. In addition, extensive variations were also observed even within the same fish species. Our results indicate that the gut microbiotas of Asian carp depend on the exact species, even when the different species were cohabiting in the same environment. This study provides some new insights into developing commercial fish feeds and improving existing aquaculture strategies.</p

Capacity-based Spatial Modulation Constellation and Pre-scaling Design

Spatial Modulation (SM) can utilize the index of the transmit antenna (TA) to transmit additional information. In this paper, to improve the performance of SM, a non-uniform constellation (NUC) and pre-scaling coefficients optimization design scheme is proposed. The bit-interleaved coded modulation (BICM) capacity calculation formula of SM system is firstly derived. The constellation and pre-scaling coefficients are optimized by maximizing the BICM capacity without channel state information (CSI) feedback. Optimization results are given for the multiple-input-single-output (MISO) system with Rayleigh channel. Simulation result shows the proposed scheme provides a meaningful performance gain compared to conventional SM system without CSI feedback. The proposed optimization design scheme can be a promising technology for future 6G to achieve high-efficiency.Comment: 6 pages,conferenc

Nearly a decade-long repeatable seasonal diversity patterns of bacterioplankton communities in the eutrophic Lake Donghu (Wuhan, China).

Uncovering which environmental factors govern community diversity patterns and how ecological processes drive community turnover are key questions related to understand the community assembly. However, the ecological mechanisms regulating long-term variations of bacterioplankton communities in lake ecosystems remain poorly understood. Here we present nearly a decade-long study of bacterioplankton communities from the eutrophic Lake Donghu (Wuhan, China) using 16S rRNA gene amplicon sequencing with MiSeq platform. We found strong repeatable seasonal diversity patterns in terms of both common (detected in more than 50% samples) and dominant (relative abundance &gt;1%) bacterial taxa turnover. Moreover, community composition tracked the seasonal temperature gradient, indicating that temperature is a key environmental factor controlling observed diversity patterns. Total phosphorus also contributed significantly to the seasonal shifts in bacterioplankton composition. However, any spatial pattern of bacterioplankton communities across the main lake areas within season was overwhelmed by their temporal variabilities. Phylogenetic analysis further indicated that 75%-82% of community turnover was governed by homogeneous selection due to consistent environmental conditions within seasons, suggesting that the microbial communities in Lake Donghu are mainly controlled by niche-based processes. Therefore, dominant niches available within seasons might be occupied by similar combinations of bacterial taxa with modest dispersal rates throughout different lake areas

Detection and Seismic Study of Gravity and Rossby Mode Pulsations in Four Contact Binaries

We report the detection of gravity ( g ) and Rossby ( r ) mode pulsations of four short-period eclipsing binaries, KIC 5439790, KIC 7501230, KIC 9350889, and KIC 9453192 based on the 4 yr Kepler high-precision photometry. Light-curve modeling reveals that the four binaries are all contact systems with small mass ratios. We study the short-term variability of the light-curve residuals after the removal of the binary model and attribute them to the g- and r -mode pulsations that stem from the primary stars. By introducing a new criterion, we attempt to identify period-spacing patterns in the Fourier spectra, which refers to the determination of the rotation rates of stellar interior and envelope as well as the asymptotic period spacings of the pulsating stars. It is interesting to find that the rotation rates of the stellar envelopes are all nearly equal to the orbits. The near-core rotations, however, are significantly slower by about 10%. Based on the derived asymptotic period spacings, stellar parameters were constrained from asteroseismology models. The pulsators are revealed to be evolved main-sequence stars with high metallicities

Research on Rock Minerals and IP Response Characteristics of Shale Gas Reservoir in Sichuan Basin

As a kind of clean energy, shale gas has attracted much attention, and the exploration and development potential of shale gas resources in the middle and deep layers is huge. However, due to the changeable geological and burial conditions, complex geophysical responses are formed. Therefore, studying the characteristics of reservoir rock minerals and their complex resistivity response characteristics is helpful to deepen the understanding of the electrical characteristics of shale gas reservoirs and provide theoretical basis and physical basis for exploration and development. The study is based on shale samples from the Longmaxi Formation to the Wufeng Formation of a shale gas well in southern Sichuan, China, and the mineral composition and complex resistivity of shale are measured. Through inversion of complex resistivity model, four IP parameters, namely zero-frequency resistivity, polarizability, time constant and frequency correlation coefficient, are extracted, and the relationship between mineral components of rock samples and IP parameters is analyzed. It is found that the polarizability gradually increases and the resistivity gradually decreases with the increase in borehole depth. With the increase in pyrite content, the polarization increases and the resistivity decreases. The corresponding relational model is established, and it is found that the polarizability is highly sensitive to the characteristic mineral pyrite, which provides more effective data support for the subsequent deep shale gas exploration

The Nitrogen Removal Performance and Functional Bacteria in Heterotrophic Denitrification and Mixotrophic Denitrification Process

The heterotrophic and autotrophic synergistic denitrification (HAD) system can effectively remove sulfide, nitrate, and organic carbon pollutants from municipal wastewater. However, the effect of sulfide on the functional bacteria in the denitrification system is still unclear. To better understand the mechanism of sulfide affected on bacteria in the system, the up-flow anaerobic sludge blanket (UASB) reactor was operated continuously under heterotrophic (no sulfide added) and mixotrophic conditions (with increased sulfide contents) for 120 days. The contents of protein (PN) in extracellular polymeric substances (EPS) were significantly increased with the addition of sulfide, which enhanced the flocculation of sludge and was beneficial to the formation of high-density microorganism communities. The dominant bacteria showed large differences under different nutrient conditions. The abundances of Thauera increased from 4.13% to over 12.94%, and that of Dechloromonas and Thiobacillus were 2.61–3.01% and 1.04–2.66% respectively after added sulfide. And the efficient performance of the system in mixotrophic conditions was accomplished with the interaction of heterotrophic sulfide-oxidizing, nitrate-reducing bacteria (Thauera, Dechloromonas), autotrophic sulfide-oxidizing, nitrate-reducing bacteria (Thiobacillus) and heterotrophic nitrate-reducing bacteria (Rubrivivax, Acidovorax, Simplicispira, Alicycliphilus). Moreover, the abundances of Nar G, Nap A, Nir S, Nor B, and Nos Z were significantly enhanced in mixotrophic conditions, indicating that the nitrogen metabolism potential of the system was also improved after added sulfide. These results elucidated the reasons for the enhanced denitrifying capacity of the system by adding S2− from the microbiological point of view and provided a theoretical basis for the establishment of an efficient denitrification system