Litter quality and decomposer complexity co-drive effect of drought on decomposition

Litter decomposition is key to ecosystem carbon(C)and nutrient cycling,but this process is anticipated to weaken due to projected more extensive and prolonged drought.Yet how litter quality and decomposer community complexity regulate decomposition in response to drought is less understood.Here,in a five-year manipulative drought experiment in a Masson pine forest,leaf litter from four subtropical tree species(Quercus griffthii Hook.f.&Thomson ex Miq.,Acacia mangium Willd.,Pinus massoniana Lamb.,Castanopsis hystrix Miq.)representing different qualities was decomposed for 350 d in litterbags of three different mesh sizes(i.e.,0.05,1,and 5 mm),respectively,under natural conditions and a 50%throughfall rain exclusion treatment.Litterbags of increasing mesh sizes discriminate decomposer communities(i.e.,microorganisms,microorganisms and mesofauna,microorganisms and meso-and macrofauna)that access the litter and represent an increasing complexity.The amount of litter C and nitrogen(N)loss,and changes in their ratio(C/N_(loss)),as well as small and medium-sized decomposers including microorganisms,nematodes,and arthropods,were investigated.We found that drought did not affect C and N loss but decreased C/N_(loss)(i.e.,decomposer N use efficiency)of leaf litter irrespective of litter quality and decomposer complexity.However,changes in the C/N_(loss)and the drought effect on C loss were both dependent on litter quality,while drought and decomposer complexity interactively affected litter C and N loss.Increasing decomposer community complexity enhanced litter decomposition and allowing additional access of meso-and macro-fauna to litterbags mitigated the negative drought effect on the microbial-driven decomposition.Furthermore,both the increased diversity and altered trophic structure of nematode due to drought contributed to the mitigation effects via cascading interactions.Our results show that litter quality and soil decomposer community complexity co-drive the effect of drought on litter decomposition.This experimental finding provides a new insight into the mechanisms controlling forest floor C and nutrient cycling under future global change scenarios.

Variational Mode Decomposition-Informed Empirical Wavelet Transform for Electric Vibrator Noise Analysis

Electric vibrators find wide applications in reliability testing, waveform generation, and vibration simulation, making their noise characteristics a topic of significant interest. While Variational Mode Decomposition (VMD) and Empirical Wavelet Transform (EWT) offer valuable support for studying signal components, they also present certain limitations. This article integrates the strengths of both methods and proposes an enhanced approach that integrates VMD into the frequency band division principle of EWT. Initially, the method decomposes the signal using VMD, determining the mode count based on residuals, and subsequently employs EWT decomposition based on this information. This addresses mode aliasing issues in the original method while capitalizing on VMD’s adaptability. Feasibility was confirmed through simulation signals and ultimately applied to noise signals from vibrators. Experimental results demonstrate that the improved method not only resolves EWT frequency band division challenges but also effectively decomposes signal components compared to the VMD method.

Isolation,Screening and Identification of Cellulose Decomposing Strains in Straw-amended Soil

[Objective]The aim was to isolate cellulose decomposing strains with high activity from straw-amended soil.[Method]Screening of CMC solid culture and shaking culture rescreening were carried out to obtain cellulose decomposing strains with high activity from the corn straw amended soil,which were analyzed by 16rDNA sequence analysis.[Result]A bacterium and a fungus with higher endonucleases activity were obtained through preliminary screening and secondary screening,a fungus with higher filter paper enzyme activity,and a bacterium（NO.5 strain） with higher of both filter paper enzyme activity and CMC enzyme activity were obtained.The result of 16S rDNA sequence analysis showed that the similarity was 100% between NO.5 strain and Bacillus subtilis.[Conclusion]NO.5 strain was identified as Bacillus subtilis.

Isolating and Screening of Effective Decomposing Strain of Silkworm Chrysalis Protein and Study on Parts of Its Enzymatic Properties

[Objective] The research aimed to obtain an effectively-decomposing strain of silkworm chrysalis protein and discuss its enzymatic properties.[Method] The effectively-decomposing bacteria of protein was isolated from the decayed silkworm chrysalis by using dilution plate and its enzymatic properties were tested after primary screening and second screening.The enzyme activity was determined and the intermediate and small molecule protein content in silkworm chrysalis was measured after solid-state fermentati...

Screening on oil-decomposing microorganisms and application in organic waste treatment machine

As an oil-decomposable mixture of two bacteria strains(Bacillus sp. and Pseudomonas sp.), Y3 was isolated after 50 d domestication under the condition that oil was used as the limited carbon source. The decomposing rate by Y3 was higher than that by each separate individual strain, indicating a synergistic effect of the two bacteria. Under the conditions that T=25—40℃,pH=6—8, HRT(Hydraulic retention time)=36 h and the oil concentration at 0.1%, Y3 yielded the highest decomposing rate of 95.7 %. Y3 was also applied in an organic waste treatment machine and a certain rate of activated bacteria was put into the stuffing. A series of tests including humidity, pH, temperature, C/N rate and oil percentage of the stuffing were carried out to check the efficacy of oil-decomposition. Results showed that the oil content of the stuffing with inoculums was only half of that of the control. Furthermore, the bacteria were also beneficial to maintain the stability of the machine operating. Therefore, the bacteria mixture as well as the machines in this study could be very useful for waste treatment.

Stimulatory effects of biosurfactant produced by Pseudomonas aeruginosa BSZ-07 on rice straw decomposing

Biosurfactant,produced by Pseudomonas aeruginosa BSZ-07,was added to the dee straw decomposing process to enhance the production of reducing sugars.Observed by Fourier Transform InfraRed(FT-IR)and Nuclear Magnetic Resonance(NMR)analysis, the purified biosurfactant was considered as a mixture of RL1 and RL2,which are two different types of rhamnolipids.Two different adding methods,adding the purified rhamnolipid and the on-site production of it were compared.The results showed that 0.5 g/L was the optimum co...

Effect of alginic acid decomposing bacterium on the growth of Laminaria japonica (Phaeophyceae)

We collected the diseased blades of Larninaria japonica from Yantai Sea Farm from October to December 2002, and the alginic acid decomposing bacterium on the diseased blade was isolated and purified, and was identified as A lteromonas espejiana. This bacterium was applied as the causative pathogen to infect the blades of L. japonica under laboratory conditions. The aim of the present study was to identify the effects of the bacterium on the growth of L. japonica, and to find the possibly effective mechanism. Results showed that： （1）The blades of L.japonica exhibited symptoms of lesion,bleaching and deteriortion when infected by the bacterium. and their growth and photosynthesis were dramatically suppressed. At the same time, the reactive oxygen species （ROS） generation enhanced obviously, and the relative membrane permeability increased significantly. The contents of malonaldehyde （MDA） and free fatty acid in the microsomol membrane greatly elevated, but the phospholipid content decreased. Result suggested an obvious peroxidation and deesterrification in the blades of L. japonica when infected by the bacterium. （2） The simultaneous assay on the antioxidant enzyme activities demonstrated that superoxide dismutase （SOD） and catalase （CAT） increased greatly when infected by the bacterium, but glutathione peroxidase （Gpx） and ascorbate peroxidase （APX） did not exhibit active responses to the bacterium throughout the experiment. （3） The histomorphological observations gave a distinctive evidence of the severity of the lesions as well as the relative abundance in the bacterial population on the blades after infection. The bacterium firstly invaded into the endodermis of L. japonica and gathered around there, and then resulted in the membrane damage, cells corruption and ultimately, the death of L. japonica.

An Approach for Improving Short-Term Prediction of Summer Rainfall over North China by Decomposing Interannual and Decadal Variability

A statistical downscaling approach was developed to improve seasonal-to-interannual prediction of summer rainfall over North China by considering the effect of decadal variability based on observational datasets and dynamical model outputs.Both predictands and predictors were first decomposed into interannual and decadal components.Two predictive equations were then built separately for the two distinct timescales by using multivariate linear regressions based on independent sample validation.For the interannual timescale,850-hPa meridional wind and 500-hPa geopotential heights from multiple dynamical models＇ hindcasts and SSTs from observational datasets were used to construct predictors.For the decadal timescale,two well-known basin-scale SST decadal oscillation （the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation） indices were used as predictors.Then,the downscaled predictands were combined to represent the predicted/hindcasted total rainfall.The prediction was compared with the models＇ raw hindcasts and those from a similar approach but without timescale decomposition.In comparison to hindcasts from individual models or their multi-model ensemble mean,the skill of the present scheme was found to be significantly higher,with anomaly correlation coefficients increasing from nearly neutral to over 0.4 and with RMSE decreasing by up to 0.6 mm d-1.The improvements were also seen in the station-based temporal correlation of the predictions with observed rainfall,with the coefficients ranging from-0.1 to 0.87,obviously higher than the models＇ raw hindcasted rainfall results.Thus,the present approach exhibits a great advantage and may be appropriate for use in operational predictions.

An initial study of insect succession on decomposing rabbit carrions in Harare,Zimbabwe

Objective:To investigate insects visiting sun exposed and shaded decomposing rabbit carcasses and to establish the relationship between insects and carcasses which may be of forensic importance in Harare.Methods:Two rabbits weighing 2.3 kg and 2.5 kg were killed by sharp blows on the head.One was exposed to the sun while the other was placed under shade.The carcasses were allowed to decompose and insects were collected twice a day for the first week and thereafter once a day up to the end of the 7 weeks.Maggots were also collected from the decomposing carcasses and reared.Results:Five dipteran families(Galliphoridae,Muscidae,Sarcophagidae,Phoridae and Drosophilidae)were identified from the sun-exposed carcass.Species collected included Lucilia cuprina(L.cuprina),Chrysomya albiceps(C.albiceps),Musca domestica,Sarcophaga sp.and Drosophila sp.Four families(Calliphoridae,Muscidae,Phoridae,Anthomyiidae)were identified from the shaded carcass.Representatives of these families included L cuprina,C.albiceps,Musca domestica,and Hydrotaea sp.Three Coleopteran families(Histeridae,Cleridae and Dermestidae)were identified from hodt carcasses.The observed species were Saprinus sp,Necrobia rufipes and Dermestes sp.Fomicidae(Hymenoptera)was represented by only one species(Pheidoie sp.)Flies which emerged from the rearing units were L cuprina,Lucilia sp.,C.albiceps,Sarcophaga sp.and Sepsis sp.).Conclusions:Of the dipteran species collected during the study,L cuprina and C.albiceps could be important for further forensic studies since they were collected from the carcasses and also observed from the rearing units.

Optimised Spatial Sampling Scheme for Soil Electriclal Conductivity Based on Variance Quad-Tree (VQT) Method

The acquisition of precise soil data representative of the entire survey area, is a critical issue for many treatments such as irrigation or fertilization in precision agriculture. The aim of this study was to investigate the spatial variability of soil bulk electrical conductivity （ECb） in a coastal saline field and design an optimized spatial sampling scheme of ECb based on a sampling design algorithm, the variance quad-tree （VQT） method. Soil ECb data were collected from the field at 20 m interval in a regular grid scheme. The smooth contour map of the whole field was obtained by ordinary kriging interpolation, VQT algorithm was then used to split the smooth contour map into strata of different number desired, the sampling locations can be selected within each stratum in subsequent sampling. The result indicated that the probability of choosing representative sampling sites was increased significantly by using VQT method with the sampling number being greatly reduced compared to grid sampling design while retaining the same prediction accuracy. The advantage of the VQT method is that this scheme samples sparsely in fields where the spatial variability is relatively uniform and more intensive where the variability is large. Thus the sampling efficiency can be improved, hence facilitate an assessment methodology that can be applied in a rapid, practical and cost-effective manner.

Preparation of nanostructure silver powders by mechanical decomposing and mechanochemical reduction of silver oxide

The mechanical decomposing and mechanochemical reductions of silver oxide for preparation of nanocrystalline silver powders by high planetary ball mill was investigated. XRD and HRSEM techniques were used to characterize the structural evolution and morphological changes of products. The results show that the nanostructured silver with an average crystallite size of 14 nm and internal strain of 0.75% is synthesized by mechanical decomposing of Ag2O after 95 h milling. While, the product of mechanochemical reduction of silver oxide using graphite after 22 h milling is nanostructured silver with an average crystallite size of 28 nm and internal strain of 0.44%.

Screening of cellulose decomposing fungi in sandy dune soil of Horqin Sandy Land

Cellulose decomposing fungi play an important role in litter decomposition and are decisive in nutrient cycling in sandy land ecosystems. Thirty-one strains were isolated to select efficient cellulose decomposers, and four efficient cellulose decomposing fungi （NM3-1, NM3-2, NM3-3, and NM3-4） were screened using a CMC （carboxymethyl cellulose） carbon source in dune soil of Horqin Sandy Land. They were identified as Asperigillus calidoustus, Fusarium oxysporum, Fusarium solani, and Hypocrea lixii by rDNA-ITS molecular biological methods. Cloth decomposition rates were 15.71%, 15.89%, 17.29%, and 17.89% by the four efficient decomposers incubated for 30 days, respectively. Screening of efficient cellulose decomposers can not only increase the dune soil functional microbe bank, but can also accelerate litter decom- position and available nutrient input in the Horqin Sandy Land.

Short-range structural change in indium melt by Gaussian peaks decomposing of RDF

Liquid indium's structure was studied at 280, 390, 550, 650, and 750 deg Crespectively by using an elevated temperature X-ray diffractometer, and its radial distributionfunction (RDF) at different temperatures was decomposed into 4 Gaussian peaks in the range of0.2-0.6nm. Positions of the decomposed Gaussian peaks were compared with the nearest and the secondnearest neighbor atomic distances, respectively. It is shown that the position of the firstdecomposed Gaussian peak is similar to the nearest neighbor atomic distance in liquid In at thecorresponding temperature, and that of the third decomposed Gaussian peak is similar to the secondnearest neighbor atomic distance. Moreover, the first and the third Gaussian peaks correspond to thefirst and the second atom shells of liquid In at the corresponding temperatures, respectively.Therefore, the position and the area of Gaussian peaks can represent the position and atom number ofcorresponding shells. Based on this result, short-range structural changes in liquid In wasstudied. It was found that the first and the second shells are close to the referred atom, and theatom number at the shells decreases with the increasing temperature from 280 to 750 deg C. Indifferent ranges of temperature, structural changes in the first and the second shells showdifferent features.

一种支持多维空间数据管理的Quad-tree索引结构

本文讨论一种支持多维空间数据管理的Quad-tree索引结构,主要解决多维空间数据的快速查找问题。Quad-tree索引组织把索引空间划分为若干规则子空间,使得这些空间之间能建立起包含偏序关系,从而实现对空间数据的索引直接查找。文中还讨论了怎样用B^+树实现这种Quad-tree索引结构。

The effects of the environmental factors on Laminaria disease caused by alginic acid decomposing bacteria

-The rot disease of Laminaria occurs often in nurseries of sporeling and commercial cultivation in the sea and results in economic loss greatly. Usually the disease outbreaks accompanied with massive multiplication of alginic acid decomposing bacteria. From the section of the decaying Lamuutria which resulted from the inoculation of alginic acid decomposing bacteria, it was observed that the bacteria invaded the epiderm of the Laminaria surface at first, then entered the ex-odermis, endodermis and pith. In addition, there were a great amount of bacteria in the intercellular region and a lot of free cells of the algae in the decaying areas. The wall of some free cells was decomposed, which led to soft tissue or disintegration. Alginic acid decomposing bacteria are normal epiphytic microorganisms growing on Lamuutria surface. These bacteria do not cause disease at normal environmental conditions. The experiments showed that the unfavourable conditions, e. g. , wounding, overcrowding, high temperature reduced the ability of antibacterial activity and made the algae more susceptible to the pathogens and favoured the multiplication of alginic acid decomposing bacteria and finally led to the disease outbreak. The unfavourable environmental factors which resulted from a variety of reasons were the main cause of the disease.

Isolation and Identification of a Cellulose-Decomposing Fungal Strain

In this study, a cellulose-decomposing fungal strain was isolated from the fertile soil and named F18. The cultural characteristics and morphological characteristics of fungal strain F18 were investigated and its ITS sequence was analyzed. According to the experimental results, fungal strain F18 belonged to Asper- g///us n/ger, which had ideal decomposing effect on cellulose and showed rapid and vigorous growth on a variety of medium. This study laid a preliminary foundation for the utilization of cellulose-decomposing fungal strain F18.

Isolation and Identification of Cellulose- decomposing Bacteria from Deep-litter Systems

In this study, 43 cellulose-decomposing strains were isolated from deep-litter systems. After preliminary screening with Congo red identification medium and filter paper strip medium, five strains with large transparent circles that disintegrated filter paper strips were obtained. After further liquid fermentation, CMC activity, FPA activity and natural eellulase activity of these five strains were determined, and two cellulose-decomposing strains with higher enzyme activity were screened, which were named F7 and F21. Based on molecular biological identification and phylogenetic analysis of 16S rRNA gene sequences, these two cellulose- decomposing strains were identified as Bacillus subtilis and Streptomyces sp. , respectively.

Molecular Dynamics Simulation of Hydrate Decomposition Under Action of Alcohol Inhibitors

The molecular dynamics method is used to investigate decomposition of methane hydrate at different temperatures,pressures and concentrations of inhibitor.By analyzing the parameters of system conformation,mean square displacement and radial distribution function,the decomposition of hydrate in the presence of alcohol inhibitors ethylene glycol and glycerol is explored.The results show that the hydroxyl groups in alcohol molecules can destroy the cage structure of hydrate,and form hydrogen bonds with nearby water molecules to effectively prevent the reformation of hydrate.Therefore,ethylene glycol and glycerol serve as inhibitors of methane hydrate,furthermore,in terms of inhibition effect,glycerol is better than ethylene glycol by comparing rate of hydrate decomposition.

Comparative Research on Facultative Anaerobic Cellulose Decomposing Bacteria Screened from Soil and Rumen Content and Diet of Dairy Cow

Twenty-nine facultative anaerobic cellulose-degrading bacteria were isolated from soil, rumen fluid, rumen residues and diet of dairy cow. Based on 16 Sr DNA analysis by BLAST algorithm method, the results showed that most of the strains were Bacillus genera, and six of the 29 strains were bigger than 10 mm of diameter of clear zones. For them, two strains were isolated from rumen fluid(L5 and L7) and other two were isolated from rumen residue(N5 and N9), while others were isolated from soil(T1) and diet(S6), respectively. Strains from rumen fluid and residue had higher activities of FPCase and CMCase, but lower β-glucosidases.

Uniquely Decomposable Constellation Group-Based Sparse Vector Coding for Short Packet Communications

Sparse vector coding(SVC)is emerging as a potential technology for short packet communications.To further improve the block error rate(BLER)performance,a uniquely decomposable constellation group-based SVC(UDCG-SVC)is proposed in this article.Additionally,in order to achieve an optimal BLER performance of UDCG-SVC,a problem to optimize the coding gain of UDCG-based superimposed constellation is formulated.Given the energy of rotation constellations in UDCG,this problem is solved by converting it into finding the maximized minimum Euclidean distance of the superimposed constellation.Simulation results demonstrate the validness of our derivation.We also find that the proposed UDCGSVC has better BLER performance compared to other SVC schemes,especially under the high order modulation scenarios.