In this letter, we consider the multiantenna spectrum sensing for correlated signal in a cognitive radio network, where uncalibrated multiple antennas are employed at the secondary user to detect the ...presence of the primary user (PU). Under such a scenario, we demonstrate that the correlation function matrices of the received signals differ between the null hypothesis and the alternative hypothesis, which can be leveraged to probe the state of PU. Based on this, a correlation-based local average variance (CLAV) detection method is proposed to exploit the correlated property of the primary signals. Also, its asymptotic distribution under the null hypothesis is derived with the aid of the central limit theorem, which enables us to theoretically obtain the decision threshold of the CLAV method. Finally, we carry out the simulation results to illustrate the superior performance of proposed method compared to the conventional methods.
Different fertilization regimes can substantially influence soil fungal community composition, yet fewer studies try to control for the effects of nitrogen input. Here, we investigated the impact of ...fertilization with equal nitrogen upon soil properties and soil fungal diversity and community composition in the North China Plain in a long-term field experiment. Long-term (32 years) fertilization regimes were applied with equal amounts of nitrogen: no chemical fertilizer or organic manure; chemical fertilization only; organic manure fertilization only, and; combination of 1/2 chemical fertilizer and 1/2 organic manure. Then we investigated the influence of these four fertilization regimes to soil properties, fungal diversity and community composition. The results showed that applying organic manure significantly influenced soil properties. Illumina MiSeq sequencing and its analysis revealed that organic manure fertilization significantly changed soil fungal alpha diversity, but chemical fertilization did not. Although soil fungal community composition did not differ significantly among all the fertilization regimes at the phylum and class levels, they did show differences in the abundance of dominant fungi. Yet at the genus level, soil fungal community composition, abundance, and beta diversity was affected by all fertilization regimes. Application of organic manure also reduced the abundance of soil-born fungal pathogens such as Fusarium. Our results suggest that long-term application of organic manure could markedly improve soil properties, altering soil fungal community composition and its diversity. Moreover, organic manure fertilization could limit soil-born fungal diseases, to further contribute to soil ecosystem sustainability.
The multiantenna spectrum sensing (MSS) problem for correlated signal is addressed in this correspondence. First, the zero-lag and non-zero-lag covariance matrices are established, respectively, to ...capture the correlation feature of primary signals. Then, two scenarios are considered: 1) the noises at different antennas are spatially white; 2) the noises at different antennas are spatially correlated. Afterward, two variants of the covariance detection method are devised to detect the presence of primary user. Also, we derive the approximate closed-form expressions to calculate the decision thresholds of the proposed two methods. Simulation results are presented to demonstrate the superiority of the proposed two methods over the conventional MSS methods.
A new drying technology, far-infrared radiation heating assisted pulsed vacuum drying (FIR-PVD) was applied to process blueberries. Influences of drying temperature, vacuum pressure duration (VPD), ...and ambient pressure duration (APD) on drying characteristics and quality attributes of blueberries were investigated under FIR-PVD. Results showed that drying temperature, APD, and VPD had significant influence on drying time and quality attributes of dried blueberries expect for color and cohesiveness. Compared to hot air dried blueberries, FIR-PVD seriously damaged the cellular walls of blueberries during drying at 65 °C. The highest total phenolics (TP) and total monomeric anthocyanins (TMA) contents of dried blueberries were obtained at 65 °C with pulsed ratio of 15 min: 4 min and 15 min: 2 min, respectively. The FIR-PVD products obtained lower color difference, better mechanical properties and rehydration performance and maintained higher antioxidant capacity by shortening drying time, reducing exposure to oxygen, and modifying the microstructure compared to hot air drying.
Blueberry is a popular function fruit around the world. With high moisture content and tender tissue, fresh blueberry is very susceptible to microbial infection even under low temperature storage conditions. Drying is a good alternative to extend the shelf life and increase the availability of fresh blueberries. However, the existence of waxy hydrophobic layer covered the surface of blueberries inhibits moisture diffusion during drying. Chemical dipping and thermal blanching pretreatments were usually used to reduce the influence of skin hydrophobicity and promote moisture diffusion. Nevertheless, the chemical additive residue leads to food safety risk and it's a big challenge to deal with the corrosive waste chemical solutions, while thermal blanching resulted a high loss of bioactive compounds. FIR-PVD is a recent developed emerging drying technology to process berries with waxy layer beyond pretreatments. Results indicated that FIR-PVD is a very promising technology for processing blueberries with the improvement of drying efficiency and quality attributes.
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•FIR-PVD promoted drying process and preserved blueberry quality.•FIR-PVD seriously damaged the cellular walls of blueberries.•FIR-PVD samples maintained higher antioxidant capacity.•More porous microstructures were observed in FIR-PVD products.•FIR-PVD products showed better mechanical properties and rehydration performance.
As one of the staple food crops, rice（Oryza sativa L.） is widely cultivated across China, which plays a critical role in guaranteeing national food security. Most previous studies on grain yield ...or/and nitrogen use efficiency（NUE） of rice in China often involved site-specific field experiments, or small regions with insufficient data, which limited the representation for the current rice production regions. In this study, a database covering a wide range of climate conditions, soil types and field managements across China, was developed to estimate rice grain yield and NUE in various rice production regions in China and to evaluate the relationships between N rates and grain yield, NUE. According to the database for rice, the values of grain yield, plant N accumulation, N harvest index（HIN）, indigenous N supply（INS）, internal N efficiency（IE_N）, reciprocal internal N efficiency（RIE_N）, agronomic N use efficiency（AE_N）, partial N factor productivity（PEPN）, physiological N efficiency（PE_N）, and recover efficiency of applied N（RE_N） averaged 7.69 t ha~（–1）, 152 kg ha~（–1）, 0.64 kg kg~（–1）, 94.1 kg kg~（–1）, 53.9 kg kg~（–1）, 1.98 kg kg~（–1）, 12.6 kg kg~（–1）, 48.6 kg kg~（–1）, 33.8 kg kg~（–1）, and 39.3%, respectively. However, the corresponding values all varied tremendously with large variation. Rice planting regions and N rates had significant influence on grain yield, N uptake and NUE values. Considering all observations, N rates of 200 to 250 kg ha~（–1） commonly achieved higher rice grain yield compared to less than 200 kg N ha~（–1） and more than 250 kg N ha~（–1） at most rice planting regions. At N rates of 200 to 250 kg ha~（–1）, significant positive linear relationships were observed between rice grain yield and AE_N, PE_N, RE_N, IE_N, and PFPN, and 46.49, 24.64, 7.94, 17.84, and 88.24% of the variation in AE_N, PE_N, RE_N, IE_N, and PFPN could be explained by grain yield, respectively. In conclusion, in a reasonable range of N application, an increase in grain yield can be achieved accompanying by an acceptable NUE.
Humic acid (HA) is a readily available and low-cost material that is used to enhance crop production and reduce nitrogen (N) loss.However,there is little consensus on the efficacy of different HA ...components.In the current study,a soil column experiment was conducted using the 15N tracer technique in Dezhou City,Shandong Province,China,to compare the effects of urea with and without the addition of weathered coal-derived HA components on maize yield and the fate of fertilizerderived N (fertilizer N).The HA components were incorporated into urea by blending different HA components into molten urea to obtain the three different types of HA-enhanced urea (HAU).At harvest,the aboveground dry biomass of plants grown with HAU was enhanced by 11.50-21.33％ when compared to that of plants grown with U.More significantly,the grain yields under the HAU treatments were 5.58-18.67％ higher than the yield under the urea treatment.These higher yields were due to an increase in the number of kernels per plant rather than the weight of individual kernels.The uptake of fertilizer N under the HAU treatments was also higher than that under the urea treatment by 11.49-29.46％,while the unaccounted N loss decreased by 12.37-30.05％.More fertilizer-derived N was retained in the 0-30 cm soil layer under the HAU treatments than that under the urea treatment,while less N was retained in the 30-90 cm soil layer.The total residual amount of fertilizer N in the soil column,however,did not differ significantly between the treatments.Of the three HAU treatments investigated,the one with an HA fraction derived from extraction with pH values ranging from 6 to 7,resulted in the best improvement in all assessment targets.This is likely due to the abundance of the COO/C-N=O group in this HA component.
Olivine is a ubiquitous mineral in mafic-ultramafic rocks and has been widely used as a mineral marker in various geological processes. However, its development of trace elements is limited. Here we ...present newly-obtained trace element data 7Li, 27Al, 29Si, 31P, 43Ca, 45Sc, 49Ti, 51V, 53Cr, 55Mn, 59Co, 60Ni, and 66Zn of olivine in typical mantle xenoliths, mantle peridotites in ophiolites, and plutonic rocks from layered and Alaskan-type intrusions to develop trace element proxies for the petrogenesis, mineralization and discrimination of various mafic-ultramafic rocks. Residual olivine grains in mantle xenoliths and ophiolitic peridotites, which represent residues of mantle melting, have higher Ni/Co (>20) and Ni/Mn (>2) ratios than magmatic olivine (Ni/Co < 20, Ni/Mn < 2), which are consistent with the compatibilities of these elements during partial melting and magma differentiation. Lower Ni content, and lower Ni/Co and Ni/Mn ratios at a given Fo content can distinguish olivine in Alaskan-type intrusions from layered intrusions, reflecting the nature of their mantle sources. The V and Sc contents and V/Sc ratios in olivine can distinguish mantle xenoliths (V > 2 ppm, V/Sc > 0.5) from ophiolitic peridotites (V < 2 ppm, V/Sc < 0.5), indicating a more reduced state of continental lithospheric mantle compared to the oceanic lithospheric mantle. As a consequence, the four occurrences of mafic-ultramafic rocks can be distinguished by olivine with (Sc × 10)-(Ti × 2)-Zn and V/Sc-(Co/Ni × 2)-(Zn/Mn × 5) ternary diagrams. In addition, Li, Ti and P contents in olivine are good tracers of melt/fluid metasomatism, whereas Ni/Co, Ni/Mn and Mn/Zn ratios are indicators of chromite mineralization. Therefore, trace elements in olivine can be used as chemical proxies to distinguish the origin of various mafic-ultramafic rocks, as well as the processes by which they evolved.
•Report of trace element data of olivine in typical mafic-ultramafic rocks.•Olivine trace elements as discriminator for mafic-ultramafic rocks.•Olivine trace element ratios as mineralizing indicators.
•A fast method for the simultaneous determination of 11 additives.•HPLC coupled with DAD and MS/MS methods are used.•Good recoveries in the range of 75.2–113.8%.•Suitable for the routine monitoring ...analysis of 11 additives.
In this study, an efficient, fast and sensitive method for the simultaneous determination of eleven synthetic color additives (Allura red, Amaranth, Azo rubine, Brilliant blue, Erythrosine, Indigotine, Ponceau 4R, New red, Sunset yellow, Quinoline yellow and Tartrazine) in flour and meat foodstuffs is developed and validated using HPLC coupled with DAD and MS/MS. The color additives were extracted with ammonia–methanol and was further purified with SPE procedure using Strata-AW column in order to reduce matrix interference. This HPLC–DAD method is intended for a comprehensive survey of color additives in foods. HPLC–MS/MS method was used as the further confirmation and identification. Validation data showed the good recoveries in the range of 75.2–113.8%, with relative standard deviations less than 15%. These methods are suitable for the routine monitoring analysis of eleven synthetic color additives due to its sensitivity, reasonable time and cost.
In current work, the influences of high-humidity hot air impingement blanching (HHAIB) time (60, 90, 120, and 150 s), drying temperature (60, 65, 70, and 75 °C), and air velocity (6, 9, and 12 m/s) ...on drying characteristics and quality attributes of broccoli florets were explored. Extreme learning machine (ELM) was employed to describe the drying behavior of broccoli florets. Results showed that proper HHAIB pretreatment can extensively increase drying rate compared to the control group (unblanched samples). The entire drying process of broccoli florets occurred in the falling period. Besides, proper HHAIB pretreatment can enhance vitamin C preservation, the color quality, and the rehydration capacity of dried broccoli florets. Based on error analysis results, the prediction accuracy of the optimal ELM model with 4-50-1 topology is found to be satisfied for the moisture ratio prediction of broccoli florets during air impingement drying process, with the R
2
,
, and MSE reached to 0.9993, 8.04e
−5
, and 2.01e
−4
, respectively.
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•A TaqMan probe real-time PCR assay for rapid detection of Enterocytozoon hepatopenaei is developed targeting the small subunit ribosomal DNA sequence.•The qPCR assay is highly ...specific and the detection limit was down to 40 copies.•The standard curve showed a good linearity in detecting of EHP SSU rDNA plasmid from 4 × 102 to 4 × 108 copies/reaction.•The assay has diagnostic sensitivity and specificity of both 100% in comparison to SYBR green I qPCR.
A TaqMan probe and a pair of specific primers were selected from the small subunit ribosomal DNA (SSU rDNA) sequence of Enterocytozoon hepatopenaei (EHP); this real-time PCR assay was developed and optimized. It showed a good linearity in detecting standards of EHP SSU rDNA fragments from 4 × 102 to 4 × 108 copies/reaction using the established method. The detection limit of the qPCR method was as low as 4 × 101 copies per reaction, which was higher than the conventional PCR and SYBR Green I-based EHP qPCR reported. Using the qPCR assay, EHP was detected in four batches of slow-growing Penaeus vannamei specimens collected from Tianjin and Zhejiang Province in China was detected using qPCR. The results showed that all the hepatopancreas from the slow-growing P. vannamei specimens were detected as EHP-positive. EHP copies of hepatopancreas in some batches had a negative correlation with the body mass index (BMI) of shrimps; however, not all batches of specimens had this negative correlation between EHP copies of hepatopancreas and BMI. This qPCR technique is sensitive, specific and easy to perform (96 tests in <3 h), which provides technical support for the detection and prevention of EHP.
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