Does Litter Decomposition Rate Indicate Species Status in the Plant Community of Alpine Meadow?

Litter decomposition is the physical and chemical breakdown of dead plant material, which is affected by the litter quality, environmental conditions and the composition of decomposer communities (Parton et al. 2007). Within biomes, environmental conditions set a similar background broadly (Berg et al. 1993; Moore et al., 2001; Raich et al. 2006; Parton et al. 2007) and microbial communities are assumed to be ‘functionally equivalent’ in terms of carbon metabolism (Andrén and Balandreau 1999). Consequently, litter quality has been considered as the predominant control on the rate of decomposition of organic matter in the ecosystem (Cornwell et al. 2008). Litter quality was closely related with nutrient use efficiency (NUE), which covers a variety of physiological processes, including the relation between the nutrient content of a plant and its growth rate (Small 1972) and the partitioning of nutrients between litterfall and ‘resorption’ pathways (Vitousek 1982). Nutrient use efficiency plays an important role in the success of plants in intra- and interspecies competition in natural eco-systems (Small 1972). Here we hypothesis that the plant community structure, which was decided by earlier NUE interactions, may correlate with the litter decomposition rates

A low-density SNP array for analyzing differential selection in freshwater and marine populations of threespine stickleback (Gasterosteus aculeatus)

BACKGROUND: The threespine stickleback (Gasterosteus aculeatus) has become an important model species for studying both contemporary and parallel evolution. In particular, differential adaptation to freshwater and marine environments has led to high differentiation between freshwater and marine stickleback populations at the phenotypic trait of lateral plate morphology and the underlying candidate gene Ectodysplacin (EDA). Many studies have focused on this trait and candidate gene, although other genes involved in marine-freshwater adaptation may be equally important. In order to develop a resource for rapid and cost efficient analysis of genetic divergence between freshwater and marine sticklebacks, we generated a low-density SNP (Single Nucleotide Polymorphism) array encompassing markers of chromosome regions under putative directional selection, along with neutral markers for background. RESULTS: RAD (Restriction site Associated DNA) sequencing of sixty individuals representing two freshwater and one marine population led to the identification of 33,993 SNP markers. Ninety-six of these were chosen for the low-density SNP array, among which 70 represented SNPs under putatively directional selection in freshwater vs. marine environments, whereas 26 SNPs were assumed to be neutral. Annotation of these regions revealed several genes that are candidates for affecting stickleback phenotypic variation, some of which have been observed in previous studies whereas others are new. CONCLUSIONS: We have developed a cost-efficient low-density SNP array that allows for rapid screening of polymorphisms in threespine stickleback. The array provides a valuable tool for analyzing adaptive divergence between freshwater and marine stickleback populations beyond the well-established candidate gene Ectodysplacin (EDA). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1471-2164-15-867) contains supplementary material, which is available to authorized users

Genome-wide SNP identification for the construction of a high-resolution genetic map of Japanese flounder (Paralichthys olivaceus) : applications to QTL mapping of Vibrio anguillarum disease resistance and comparative genomic analysis

High-resolution genetic maps are essential for fine mapping of complex traits, genome assembly, and comparative genomic analysis. Single-nucleotide polymorphisms (SNPs) are the primary molecular markers used for genetic map construction. In this study, we identified 13,362 SNPs evenly distributed across the Japanese flounder (Paralichthys olivaceus) genome. Of these SNPs, 12,712 high-confidence SNPs were subjected to high-throughput genotyping and assigned to 24 consensus linkage groups (LGs). The total length of the genetic linkage map was 3,497.29 cM with an average distance of 0.47 cM between loci, thereby representing the densest genetic map currently reported for Japanese flounder. Nine positive quantitative trait loci (QTLs) forming two main clusters for Vibrio anguillarum disease resistance were detected. All QTLs could explain 5.1-8.38% of the total phenotypic variation. Synteny analysis of the QTL regions on the genome assembly revealed 12 immune-related genes, among them 4 genes strongly associated with V. anguillarum disease resistance. In addition, 246 genome assembly scaffolds with an average size of 21.79 Mb were anchored onto the LGs; these scaffolds, comprising 522.99 Mb, represented 95.78% of assembled genomic sequences. The mapped assembly scaffolds in Japanese flounder were used for genome synteny analyses against zebrafish (Danio rerio) and medaka (Oryzias latipes). Flounder and medaka were found to possess almost one-to-one synteny, whereas flounder and zebrafish exhibited a multi-syntenic correspondence. The newly developed high-resolution genetic map, which will facilitate QTL mapping, scaffold assembly, and genome synteny analysis of Japanese flounder, marks a milestone in the ongoing genome project for this species.Peer reviewe

Whole-genome sequencing of cultivated and wild peppers provides insights into Capsicum domestication and specialization

As an economic crop, pepper satisfies people's spicy taste and has medicinal uses worldwide. To gain a better understanding of Capsicum evolution, domestication, and specialization, we present here the genome sequence of the cultivated pepper Zunla-1 (C. annuum L.) and its wild progenitor Chiltepin (C. annuum var. glabriusculum). We estimate that the pepper genome expanded similar to 0.3 Mya (with respect to the genome of other Solanaceae) by a rapid amplification of retrotransposons elements, resulting in a genome comprised of similar to 81% repetitive sequences. Approximately 79% of 3.48-Gb scaffolds containing 34,476 protein-coding genes were anchored to chromosomes by a high-density genetic map. Comparison of cultivated and wild pepper genomes with 20 resequencing accessions revealed molecular footprints of artificial selection, providing us with a list of candidate domestication genes. We also found that dosage compensation effect of tandem duplication genes probably contributed to the pungent diversification in pepper. The Capsicum reference genome provides crucial information for the study of not only the evolution of the pepper genome but also, the Solanaceae family, and it will facilitate the establishment of more effective pepper breeding programs

A review of the corrective power of personal comfort systems in non-neutral ambient environments

This paper discusses a spectrum of systems that cool or heat occupants personally, termed ‘personal comfort systems’ (PCS), in order to quantify their ability to produce comfort in ambient temperatures that are above or below the subjects’ neutral temperatures.The comfort-producing effectiveness may be quantified in terms of a temperature difference, coining the index ‘corrective power’ (CP). CP is defined as difference between two ambient temperatures at which equal thermal sensation is achieved - one with no PCS (the reference condition), and one with PCS in use.  CP represents the degree to which a PCS system may “correct” the ambient temperature toward neutrality. CP can alternatively be expressed in terms of thermal sensation and comfort survey scale units.Published studies of PCS are reviewed to extract their CP values. Cooling CP ranges from -1 to -6K, and heating CP from 2K to 10K.  The physical characteristics of the particular PCS systems are not reported in detail here, but are presented as prototypes of what is possible.  Deeper understanding of PCS will require new physiological and psychological information about comfort in local body segments and subsegments, and about spatial and temporal alliesthesia.  These topics present many opportunities for productive future research

Point Estimation Method of Electromagnetic Flowmeters Life Based on Randomly Censored Failure Data

This paper analyzes the characteristics of the enterprise after-sale service records for field failure data, and summarizes the types of field data. Maximum likelihood estimation method and the least squares method are presented for the complexity and difficulty of field failure data processing, and Monte Carlo simulation method is proposed. Monte Carlo simulation, the relatively simple calculation method, is an effective method, whose result is closed to that of the other two methods. Through the after-sale service records analysis of a specific electromagnetic flowmeter enterprises, this paper illustrates the effectiveness of field failure data processing methods

Atomistic Investigation of the Effects of Different Reinforcements on Al Matrix Composite

In this work, we studied the effects of different reinforcements on a metal matrix composite (MMC) using molecular dynamics (MD) simulations, where graphene was chosen as the two-dimensional (2D) material and diamond was selected as the three-dimensional (3D) material. Sintering and tensile processes were conducted on the MMC models containing reinforcements of various sizes, and the effects of reinforcements with the same surface area were compared. The results indicated that the 2D material was more beneficial for sintering at the heating stage, producing a higher-density structure. The volume of Al atoms fell from 752 to 736 nm3 as the graphene size in the composite system increased. However, a slight increase from 749 to 755 nm3 was observed when the diamond radius was small. Converted to relevant metrics in the experiments, the density of the composite reached 2.84 g/cc with a 3.3 wt.% addition of single-layer graphene (SLG) and 2.87 g/cc with a 15.4 wt.% addition of diamond, and the results were slightly higher than the experimental reports. Both SLG and diamond could reduce the number of arranged Al atoms from 43,550 to approximately 35,000, and bilayer graphene (BLG) with the largest size could further decrease the number of arranged atoms to nearly 30,000, implying that grain refinement could be obtained by increasing the surface area of reinforcements. Considering the scale of these models, the reinforcement size and pore location in the initial structures were deemed to have an impact on the mechanical properties. The composite with the largest proportion of SLG showed an increase of more than 1.6 GPa in tensile strength; however, BLG showed a significant drop of 1.9 GPa when stretched in the normal direction, as the large interlayer space acted as a large hole in tension. The diamond size did not appear to affect the strengthening effects. Nevertheless, the elongation values of composites with graphene were generally 35% higher than the Al-diamond composites