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In the field of genome assembly, scaffolding methods make it possible to obtain a more complete and contiguous reference genome, which is the cornerstone of genomic research. Scaffolding methods typically utilize the alignments between contigs and sequencing data (reads) to determine the orientation and order among contigs and to produce longer scaffolds, which are helpful for genomic downstream analysis. With the rapid development of high-throughput sequencing technologies, diverse types of reads have emerged over the past decade, especially in long-range sequencing, which have greatly enhanced the assembly quality of scaffolding methods. As the number of scaffolding methods increases, biology and bioinformatics researchers need to perform in-depth analyses of state-of-the-art scaffolding methods. In this article, we focus on the difficulties in scaffolding, the differences in characteristics among various kinds of reads, the methods by which current scaffolding methods address these difficulties, and future research opportunities. We hope this work will benefit the design of new scaffolding methods and the selection of appropriate scaffolding methods for specific biological studies. [ABSTRACT FROM AUTHOR]

This paper deals with the semilinear Rayleigh–Stokes equation with the fractional derivative in time of order α ∈ (0 , 1) , which can be used to model anomalous diffusion in viscoelastic fluids. An operator family related to this problem is defined, and its regularity properties are investigated. We firstly give the concept of the mild solutions in terms of the operator family and then obtain the existence of global mild solutions by means of fixed point technique. Moreover, the existence and regularity of classical solutions are given. [ABSTRACT FROM AUTHOR]

The present paper is concerned with the eigenvalue problem for cone degenerate p-Laplacian. First the authors introduce the corresponding weighted Sobolev s-paces with important inequalities and embedding properties. Then by adapting Lusternik-Schnirelman theory, they prove the existence of infinity many eigenvalues and eigenfunctions. Finally, the asymptotic behavior of the eigenvalues is given. [ABSTRACT FROM AUTHOR]

This paper presents a power swing detection algorithm in multi-machine power systems, which uses wide-area synchrophasor measurements and is based on Zubov’s stability boundaries. Zubov’s boundary method, an approximation of the famous Lyapunov function, is very common for numerical analyses of power system stability. This work extends the concept of Zubov’s approximation boundaries to online protection applications. First, the proposed protection algorithm constructs a series of Zubov’s stability boundaries on power angle–frequency ($\delta$ – $\omega$) plane for generators based on real-time measurements from phasor measurement units/merging units. Then, it tracks the trajectory of each generator in the $\delta$ – $\omega$ plane after the disturbance to differentiate out-of-step (OOS) conditions from stable swings. The proposed approach is suitable for online applications, which is a significant improvement over the existing methods for swing detection since it does not require offline studies and network reduction. Effectiveness of the proposed method is shown using a single-machine infinite bus and New-England 10-machine 39-bus systems. The proposed method is also implemented in a hardware-in-the-loop setup with a customized IEC 61850-based OOS relay, and performance is compared with a commercially available relay. [ABSTRACT FROM AUTHOR]

• A synchrophasor based identification of generator coherency groups for situational awareness is presented. • New visualization for situational awareness is presented. • A generator vulnerability index (GVI) and a corresponding power system vulnerability index (SVI) are presented. • The abovementioned techniques are illustrated for a multi-area interconnected power system with utility-scale PV. • Furthermore, real-time simulation of the power system with utility-scale PV and the new tools are presented. The smart grid innovation targets at the problems of integrating large portion of intermittent generation resources such as utility-scale and rooftop photovoltaics (PVs), while ensuring both the security and reliability of the electric power grid operation during severe disturbances. To enhance the operators' performance, the information processing of the large-scale widely interconnected electric power grid needs to be simplified and presented with situational awareness (SA) in a meaningful way, for timely response by the system operators in control centers. Coherency group identification separates the generators in the system into groups that feature similar behavior, which is a method for grid simplification. Meanwhile, wide area measurement systems (WAMS) using data from phasor measurement units (PMUs) provides a solution – enhanced situational awareness to power operation control centers addressing the concerns of capturing and transmitting dynamic data in near real-time. Based upon these technologies, a synchrophasor based identification of generator coherency groups and new visualizations for SA are proposed and developed for online application with using K -harmonic means clustering. Furthermore, a generator vulnerability index (GVI) and a corresponding power system vulnerability index (SVI) are proposed based on the dynamic coherency groups identified. These indices alert system operators on the coherency behavior of the synchronous generators in the system for variations of PV power and/or under severe system disturbances. Typical results are provided for four different disturbances including sudden PV power increase and decrease, unexpected bus faults on major tie-line (inter-area) transmission corridors. In summary, new algorithms, indices and visualization tools have been developed to enhance SA and provide actionable information to system operators in control centers in the presence of variable utility-scale PV power in a power system. [ABSTRACT FROM AUTHOR]

To prevent large interconnected power system from a cascading failure, brownout or even blackout, grid operators require access to faster than real-time information to make appropriate just-in-time control decisions. However, the communication and computational system limitations of currently used supervisory control and data acquisition (SCADA) system can only deliver delayed information. However, the deployment of synchrophasor measurement devices makes it possible to capture and visualize, in near-real-time, grid operational data with extra granularity. In this paper, a cellular computational network (CCN) approach for frequency situational intelligence (FSI) in a power system is presented. The distributed and scalable computing unit of the CCN framework makes it particularly flexible for customization for a particular set of prediction requirements. Two soft-computing algorithms have been implemented in the CCN framework: a cellular generalized neuron network (CCGNN) and a cellular multi-layer perceptron network (CCMLPN), for purposes of providing multi-timescale frequency predictions, ranging from 16.67 ms to 2 s. These two developed CCGNN and CCMLPN systems were then implemented on two different scales of power systems, one of which installed a large photovoltaic plant. A real-time power system simulator at weather station within the Real-Time Power and Intelligent Systems (RTPIS) laboratory at Clemson, SC, was then used to derive typical FSI results. [ABSTRACT FROM AUTHOR]

The Natural Forest Protection (NFP) program is one of the Six Key Forestry Projects which were adopted by the Chinese Government since the 1980s to address important natural issues in China. It advanced to protecting and restoring the structures and functions of the natural forests through sustainable forest management. However, the role of forest carbon storage and tree carbon pool dynamics since the adoption of the NFP remains unknown. To address this knowledge gap, this study calculated forest carbon storage (tree, understory, forest floor and soil) in the forest region of northeastern (NE) China based on National Forest Inventory databases and field investigated databases. For tree biomass, this study utilized an improved method for biomass estimation that converts timber volume to total forest biomass; while for understory, forest floor and soil carbon storage, this study utilized forest type-specific mean carbon densities multiplied by their areas in the region. Results showed that the tree carbon pool under the NFP in NE China functioned as a carbon sink from 1998 to 2008, with an increase of 6.3 Tg C/yr, which was mainly sequestrated by natural forests (5.1 Tg C/yr). At the same time, plantations also acted as a carbon sink, reflecting an increase of 1.2 Tg C/yr. In 2008, total carbon storage in forests covered by the NFP in NE China was 4603.8 Tg C, of which 4393.3 Tg C was stored in natural forests and 210.5 Tg C in planted forests. Soil was the largest carbon storage component, contributing 69.5%-77.8% of total carbon storage; followed by tree and forest floor, accounting for 16.3%-23.0% and 5.0%-6.5% of total carbon storage, respectively. Understory carbon pool ranged from 1.9 to 42.7 Tg C, accounting for only 0.9% of total carbon storage. [ABSTRACT FROM AUTHOR]

The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and <5%, in boreal and temperate forests respectively, and thus play a minor role in total forest C storage in NE China. [ABSTRACT FROM AUTHOR]

In this work, we study the Dirichlet problem for a class of degenerate elliptic equations with singular potential on conical singular manifolds. By using the cone Sobolev inequality and Hardy inequality, the existence of nontrivial solutions has been proved. [ABSTRACT FROM AUTHOR]

The present paper is concern with the Dirichlet problem for semi-linear corner degenerate elliptic equations with singular potential term. We first give the preliminary of the framework and then discuss the weighted corner type Hardy inequality. By using the variational method, we prove the existence of multiple solutions for the Dirichlet boundary-value problem. [ABSTRACT FROM AUTHOR]

We consider the Dirichlet problem of semi-linear corner-degenerate elliptic equations with singular potentials in the subcritical case. First we introduce the weighted corner type Sobolev inequality, Poincaré inequality and Hardy inequality. Then, by using the variational method and the abstract theory for sign changing solution, we obtain the existence of infinitely many sign changing solutions in the weighted corner Sobolev space. [ABSTRACT FROM AUTHOR]

Abstract: The present paper is concerned with the existence of multiple solutions for semi-linear corner-degenerate elliptic equations with subcritical conditions. First, we introduce the corner type weighted p-Sobolev spaces and discuss the properties of continuous embedding, compactness and spectrum. Then, we prove the corner type Sobolev inequality and Poincaré inequality, which are important in the proof of the main result. [Copyright &y& Elsevier]

Abstract: In this paper, we study the Dirichlet problem for a class of semilinear totally characteristic elliptic equations with subcritical or critical cone Sobolev exponents and get the existence of infinitely many solutions in both case. [Copyright &y& Elsevier]

Abstract: In this paper, we introduce weighted p-Sobolev spaces on manifolds with edge singularities. We give the proof for the corresponding edge type Sobolev inequality, Poincaré inequality and Hardy inequality. As an application of these inequalities, we prove the existence of nontrivial weak solutions for the Dirichlet problem of semilinear elliptic equations with singular potentials on manifolds with edge singularities. [Copyright &y& Elsevier]

In present work, we first establish the corresponding Sobolev inequality and Poincaré inequality on the cone Sobolev spaces, and then, as an application of such inequalities, we prove the existence of non-trivial weak solution for Dirichlet boundary value problem for a class of non-linear elliptic equation on manifolds with conical singularities. [ABSTRACT FROM AUTHOR]

In this article, we use the cone Sobolev inequality and Poincaré inequality to prove the existence theorem for a class of semilinear degenerate elliptic equation with critical cone Sobolev exponents on manifolds with conical singularities. [ABSTRACT FROM AUTHOR]

The low cycling stability of LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) is due to structural instability during lithium insertion and removal and strong surface reactivity, and it limits widespread application. In this study, a layer of LiCoPO 4 was coated on NCM811, and electrochemical tests showed that the material had excellent high-voltage electrochemical properties. The NCM811 sample coated with 1.0 wt% LiCoPO 4 (NCM-LCP1) had a capacity of 156.5 mAh g−1 after 100 cycles at 3–4.6 V and a retention rate of 87.47%. In contrast, the capacity of unmodified NCM811 was only 96.9 mAh g−1, with a retention rate of 55.9%. An NCM-LCP1/graphite full cell demonstrated a capacity retention rate of 87.46% over 200 cycles at 3–4.3 V. By combining EIS and postcycle analyses, the stability and protection mechanism of the LiCoPO 4 layer under high voltage was confirmed. The LiCoPO 4 layer effectively prevented particle fragmentation and kept the structure stable. It also suppressed side reactions on the cathode surface. This work offers a new methodology for modifying NCM811 materials operated at 4.6 V. [Display omitted] [ABSTRACT FROM AUTHOR]

Coal-fired power plants (CFPP) can provide significant inertia and flexibility support for power systems with a high share of renewable energy (RE). The ammonia–coal co-firing technology can effectively reduce carbon emissions (CE) from CFPP. We propose a low-carbon power supply and multi-timescale energy storage system in combination with this technology. The system consists of batteries, fuel cells and the CFPP equipped with the ammonia–coal co-combustion module. It can also cope with short and long term fluctuations in RE. We use the Mixed Integer Linear Programming method to construct an optimization model for this system. We then set up six sub-cases according to the power systems in Texas, USA. Based on weekly and annual simulations of these cases, we analyze the economic and environmental performances of the proposed system with different RE shares, as well as exploring the characteristics of different energy storage methods. Compared to batteries or fuel cells only scenarios, CFPP configured with green ammonia co-firing can significantly reduce the total operating cost (TOC), CE and RE curtailment. We use the rolling horizon optimization method to simulate and calculate the distribution of ammonia storage levels throughout the year. The ammonia storage levels are high in spring and autumn and low in summer. Finally, the sensitivity and efficiency analysis of the proposed system is carried out. As far as ammonia co-firing technology allows, the higher the maximum ammonia–coal mixing ratio, the lower TOC, CE and RE curtailment. This phenomenon is more significant at a higher RE share. The overall efficiency of green ammonia synthesis and combustion for power generation is around 13.92%. It can work in synergy with batteries and fuel cells to improve efficiency and reduce the marginal cost of long-term energy storage. • A low-carbon power supply and multi-timescale energy storage system is proposed. • The system can effectively reduce carbon emissions from coal-fired power plants. • The efficiency of green NH 3 synthesis and combustion for power is about 13.92%. • The NH 3 co-firing is more applicable for islanded power systems than open systems. [ABSTRACT FROM AUTHOR]

• The sap flow of Mongolian Scots pine has significant radial variation pattern. • The radial pattern of sap flow varies with age and growing season. • There is a considerable error in sap flow assessment if single point measurements are considered. • There is a stable conversion coefficient between Js 15mm and Js mean. • The radial variation of sap flow is different in response to meteorological factors. Mongolian Scots pine (Pinus sylvestris var. mongolica) is one of the main afforestation tree species in the Three North shelterbelt project in China, and an accurate estimation of its transpiration is of importance for plantation scientific density management especially under future climate change scenarios. While radial variation in tree species sap flow is an important factor for estimating transpiration, it is usually neglected. Thus, this study selected Mongolian Scots pine of different ages (10a, 20a, 30a, 40a) to study its radial variation pattern of sap flow using the multipoint (probes of different specifications) thermal dissipation method; additionally, its response characteristics to meteorological factors in northeast China were also discussed. The results show that the radial distribution of the sap flux density varied with age and growing season. It gradually decreased from the outside to the inside of the sapwood of the 10a stand. In contrast, the sap flux densities of the 20a, 30a and 40a stands had all typical single-peak patterns, with the highest value at 15 mm from the outside of the sapwood, and then sharply decreased with increasing distance. The sap flux density in both the 10a and 20a stands slightly changed, while it a significantly change in both the 30a and 40a stands between the middle and end of the growing season occurred. Further estimation of transpiration by single point and multipoint analyses was undertaken. The single point analysis resulted in large errors of -18.81%-11.02%, -52.44%-133.47%, -10.26%-130.38% and -48.78%-162.11% in the 10a, 20a, 30a and 40a stands, respectively. However, Js 15mm was significantly correlated with the mean sap flux density of a sapwood area (Js mean) and exhibited a constant conversion coefficient. The sap flux densities of separate sapwood depths were significantly affected by meteorological factors and varied according to different meteorological factors. [ABSTRACT FROM AUTHOR]

Based on the data from China's Seventh Forest Inventory for the period of 2004-2008, area and stand volume of different types and age-classes of plantation were used to establish the relationship between biomass density and age of planted forests in different regions of the country. Combined with the plantation area in the first-stage of the Natural Forest Protection (NFP) program (1998-2010), this study calculated the biomass carbon storage of the afforestation in the first-stage of the program. On this basis, the carbon sequestration potential of these forests was estimated for the second stage of the program (2011-2020). Biomass carbon storage of plantation established in the first stage of the program was 33.67 Tg C, which was majority accounted by protection forests (30.26 Tg C). There was a significant difference among carbon storage in different regions, which depended on the relationship of biomass carbon density, forest age and plantation area. Under the natural growth, the carbon storage was forecasted to increase annually from 2011 to 2020, reaching 96.03 Tg C at the end of the second-stage of the program in 2020. The annual growth of the carbon storage was forecasted to be 6.24 Tg C/yr, which suggested that NFP program has a significant potential for enhancing carbon sequestration in plantation forests under its domain. [ABSTRACT FROM AUTHOR]

Land use changes are known to alter soil organic carbon (SOC) and microbial properties, however, information about how conversion of natural forest to agricultural land use as well as plantations affects SOC and microbial properties in the Changbai Mountains of Northeast China is meager. Soil carbon content, microbial biomass carbon (MBC), basal respiration and soil carbon mineralization were studied in five selected types of land use: natural old-growth broad-leaved Korean pine mixed forest (NF); spruce plantation (SP) established following clear-cutting of NF; cropland (CL); ginseng farmland (GF) previously under NF; and a five-year Mongolian oak young forest (YF) reforested on an abandoned GF, in the Changbai Mountains of Northeast China in 2011. Results showed that SOC content was significantly lower in SP, CL, GF, and YF than in NF. MBC ranged from 304.4 mg/kg in CL to 1350.3 mg/kg in NF, which was significantly higher in the soil of NF than any soil of the other four land use types. The SOC and MBC contents were higher in SP soil than in CL, GF, and YF soils, yielding a significant difference between SP and CL. The value of basal respiration was also higher in NF than in SP, CL, GF, and YF. Simultaneously, higher values of the metabolic quotient were detected in CL, GF, and YF soils, indicating low substrate utilization of the soil microbial community compared with that in NF and SP soil. The values of cumulative mineralized carbon and potentially mineralized carbon ( C) in NF were significantly higher than those in CL and GF, while no significant difference was observed between NF and SP. In addition, YF had higher values of C and C mineralization rate compared with GF. The results indicate that conversion from NF into agricultural land (CL and GF) uses and plantation may lead to a reduction in soil nutrients (SOC and MBC) and substrate utilization efficiency of the microbial community. By contrast, soils below SP were more conducive to the preservation of soil organic matter, which was reflected in the comparison of microbial indicators among CL, GF, and YF land uses. This study can provide data for evaluating soils nutrients under different land use types, and serve as references for the rational land use of natural forest in the study area. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to prepare a 72h-release formulation of silybin (72h-SLB) using a combination of solid dispersion, gel matrix and porous silica nanoparticles (PSNs) and to investigate the in vitro/in vivo correlations (IVIVCs). The results of scanning electron microscopy and N2 adsorption demonstrated that empty PSNs possessed a spherical shape, a highly porous structure, a large specific surface area (385.89±1.12m2/g) and a small pore size (2.74nm on average). The in vitro dissolution profiles of both 72h-SLB and silybin-loaded PSNs in different concentrations (0.01, 0.06 and 0.08M) of Na2CO3 solutions revealed that 0.06M Na2CO3 solution was the optimal medium in which silybin could be released from 72h-SLB with first-order release kinetics and from PSNs with Higuchi kinetics. Furthermore, the IVIVCs of 72h-SLB and silybin-loaded PSNs in beagle dogs were also established. Using 0.06M Na2CO3 solution as the in vitro dissolution medium, a good linear relationship could be achieved for both 72h-SLB and silybin-loaded PSNs. The findings support the fact that the 72h-SLB (consisting of solid dispersion, regular gel matrix and PSNs) together with Na2CO3 solution as an in vitro dissolution medium can be developed into a promising formulation for poorly soluble drugs, which enjoys a good IVIVC. [Copyright &y& Elsevier]

Soil microorganisms play vital roles in recovering and maintaining the health of ecosystems, particularly in fragile Karst ecosystems that are easily degraded after cultivation. We investigated the composition and diversity of soil bacterial communities, based on RFLP and 16S rDNA sequencing, in a cropland, a naturally revegetated land with former cultivation disturbance and a primeval forest in the subtropical Karst of southwest China. Our results illustrated that Proteobacteria accounted for 44.8% of the 600 tested clones, making it the most dominant phylum observed. This phylum was followed by Acidobacteria and Planctomycetes for the three Karst soils analyzed. Compared with the primeval forest soil, the proportions of Proteobacteria were decreased by 30.2 and 37.9%, while Acidobacteria increased by 93.9 and 87.9%, and the Shannon-Wiener diversity indices and the physicochemical parameters declined in the cropland and the revegetated land, respectively. Among the three soils, the proportion of dominant bacterial phyla and the diversity indices in the revegetated land were similar to the cropland, implying the bacterial community in the cropland was relatively stable, and the after-effects of cultivation were difficult to eliminate. However, similar distributions of the four Proteobacteria subphyla were observed between the revegetated land and the primeval forest soil. Furthermore, the proportion of Rhizobiales belonging to α- Proteobacteria was sharply decreased with cultivation compared to the primeval forest soil, while a small cluster of Rhizobiales recurred with vegetation recovery. These results indicated that although the subphyla of the dominant bacterial phylum had some positive responses to 20 years of vegetation recovery, it is a slow process. Our results suggest that priority should be given to conserve the primeval forest and inoculation of functional microorganisms on the basis of vegetation recovery may be more effective for the restoration of Karst ecosystems after cultivation. [ABSTRACT FROM AUTHOR]