Search

The low-rank matrix optimization with affine manifold (rank-MOA) aims to minimize a continuously differentiable function over a low-rank set intersecting with an affine manifold. This paper is devoted to the optimality analysis for rank-MOA. As a cornerstone, the intersection rule of the Fréchet normal cone to the feasible set of rank-MOA is established under some mild linear independence assumptions. Aided with the resulting explicit formulae of the underlying normal cones, the so-called F-stationary point and the α-stationary point of rank-MOA are investigated and the relationship with local/global minimizers are then revealed in terms of first-order optimality conditions. Furthermore, the second-order optimality analysis, including the necessary and sufficient conditions, is proposed based on the second-order differentiation information of the model. All these results will enrich the theory of low-rank matrix optimization and give potential clues to designing efficient numerical algorithms for seeking low-rank solutions. Meanwhile, two specific applications of rank-MOA are discussed to illustrate our proposed optimality analysis. [ABSTRACT FROM AUTHOR]

INTRODUCTION Previous studies have suggested an association between tobacco smoke exposure and allergic rhinitis. This study aimed to investigate if prenatal or postpartum smoke exposure will increase the risk of allergic rhinitis in offspring. METHODS PubMed, EMBASE, and the Cochrane library were searched from inception to July 2020 for eligible studies investigating the association between smoking exposure and allergic rhinitis. The random-effects model was adopted for the metaanalysis to obtain the summary odds ratio (OR) with a 95% confidence interval (CI). Subgroup analysis based on the age of children was performed. Sensitivity analysis was carried out to check the robustness of the results. Publication bias of included studies was assessed. RESULTS This meta-analysis included nine studies, in which six studies suggested that children exposed to prenatal smoking were more likely to develop allergic rhinitis compared with children who were never exposed (OR=1.12; 95% CI: 1.04-1.21). The subgroup analysis divided children those aged <10 years (OR=1.15; 95% CI: 1.06-1.25) and those aged >10 years (OR=0.99; 95% CI: 0.82-1.20). This metaanalysis revealed a positive relationship between postpartum smoke exposure and the development of allergic rhinitis in offspring (OR=1.19; 95% CI: 1.03-1.39) with marked heterogeneity. The subgroup analysis of age in the postnatal group showed similar results in children aged >10 years (OR=1.17; 95% CI: 1.05-1.30) and children aged <10 years (OR=1.21; 95% CI: 0.91-1.60). CONCLUSIONS This meta-analysis observed an association between parental smoking exposure and allergic rhinitis in offspring. Our findings indicated that both prenatal and postnatal smoke exposure might be risk factors for allergic rhinitis in the offspring. [ABSTRACT FROM AUTHOR]

Sea-level rise is one of the most critical challenges facing coastal ecosystems under climate change. Observations of elevated tree mortality in global coastal forests are increasing, but important knowledge gaps persist concerning the mechanism of salinity stress-induced nonhalophytic tree mortality. We monitored progressive mortality and associated gas exchange and hydraulic shifts in Sitka-spruce (Picea sitchensis) trees located within a salinity gradient under an ecosystem-scale change of seawater exposure in Washington State, USA. Percentage of live foliated crown (PLFC) decreased and tree mortality increased with increasing soil salinity during the study period. A strong reduction in gas exchange and xylem hydraulic conductivity (Ks) occurred during tree death, with an increase in the percentage loss of conductivity (PLC) and turgor loss point (πtlp). Hydraulic and osmotic shifts reflected that hydraulic function declined from seawater exposure, and dying trees were unable to support osmotic adjustment. Constrained gas exchange was strongly related to hydraulic damage at both stem and leaf levels. Significant correlations between foliar sodium (Na+) concentration and gas exchange and key hydraulic parameters (Ks, PLC, and πtlp) suggest that cellular injury related to the toxic effects of ion accumulation impacted the physiology of these dying trees. This study provides evidence of toxic effects on the cellular function that manifests in all aspects of plant functioning, leading to unfavourable osmotic and hydraulic conditions. [ABSTRACT FROM AUTHOR]

Aims: In arid regions, the succession of biological soil crusts (biocrusts) usually accompanies substantial turnover of community composition. How interspecific interactions among biocrust-forming mosses, lichens, algae and cyanobacteria change along the successional gradient is largely unknown. According to the stress gradient hypothesis (SGH), the frequency or intensity of facilitative and competitive interactions within the community will vary along an environmental stress gradient, with an increasing role of competition relative to facilitation under more benign environmental conditions. In the process of biocrust succession, decreasing soil stress also occurs because of slow soil amelioration, which meets the assumption of the SGH. Therefore, we hypothesize that the changes in facilitative and competitive interactions within biocrust communities will follow the prediction of the SGH and that the nature of biocrust interactions will also change. Location: Sand-binding vegetation belts for the Baotou–Lanzhou railway at the southeast fringe of the Tengger Desert in the Shapotou region of the Ningxia Hui Autonomous Region, western China. Methods: We conducted a field evaluation at five adjacent sand-binding vegetation belts built in chronosequence to study the successional gradient. Small-scale patterns of co-occurrence and null models were used to evaluate the community-level interspecific interactions among the biocrust-forming mosses, lichens, algae and cyanobacteria. In addition, an accessory method of species-pair co-occurrence based on null models was also applied to potentially identify the nature of the interspecific interactions within the biocrusts and for the causal investigation of these patterns. Results: A strong spatial segregation of co-occurrence patterns occurred between cyanobacteria and algae and species of mosses and lichens at early succession, and occurred among species of mosses and lichens at late succession, while the weak spatial aggregation between lichen species only occurred at middle succession. Conclusions: Negative interspecific interactions were prevalent within biocrusts throughout succession. The co-occurrence patterns at both the community and species-pair levels are consistent, supporting the unimodal version of the SGH that species interactions shift toward competition under extremely stressed conditions. Given the lack of research on interspecific interactions in biocrusts, our study is important for obtaining a deeper understanding of biocrust succession. [ABSTRACT FROM AUTHOR]

To understand the mechanism underlying Dioscin inhibition of polycystic ovary syndrome, we have examined its effects on ovarian granulosa cells from letrozole-treated rats. To this end, Western blot was utilized to determine changes in the levels of Bcl-2, cleaved caspase-3, caspase-3, and phosphatidylinositol 3-kinase (PI3K)/protein kinase B pathway after Dioscin treatment in letrozole-treated rats. Dioscin ameliorated polycystic ovary syndrome by reducing the serum level of testosterone and increasing progesterone levels. It also inhibited proliferation and induced apoptosis of ovarian granulosa cells in the rat model by decreasing the level of Bcl-2 and elevating cleaved caspase-3. Western blot analysis revealed that Dioscin suppressed the PI3K/Akt pathway by inhibiting p-AKT/AKT. SC79, a p-AKT/AKT activator, reversed the effects of Dioscin on the proliferation and apoptosis of ovarian granulosa cells. In conclusion, Dioscin might present a novel therapeutic opportunity for patients with polycystic ovary syndrome. [ABSTRACT FROM AUTHOR]

A few studies suggested the contribution of PPARs to the etiology of schizophrenia (SCZ). However, it is still not clear whether variants in PPAR-encoding genes have a direct association with SCZ. The potential linkage between SCZ and the variants within PPAR encoding genes (PPARA, PPARD, and PPARG) was tested in a large cohort genome-wide association study (GWAS). Then, a mega-analysis was conducted using 14 gene expression profiling experiments in various human brain regions. Finally, the expression levels of the three PPAR-encoding genes were quantified in early-onset SCZ patients. Only one PPARG polymorphisms, rs62242085, presented a minor frequency deviation in the SCZ cohort (P-value = 0.035). None of the PPAR-encoding genes presented significant expression change within the brain regions profiled in 14 datasets acquired from different populations (P-value > 0.14) or in the whole blood of early-onset overall SCZ patients (P-value > 0.22). However, compared with healthy female controls, female early-onset SCZ patients presented a moderate but significant decrease in the expression level of PPARD (LFC = 0.55; P-value = 0.02) and a strong, but non-significant decrease in expression of PPARG (LFC = 1.30; P-value = 0.13). Our results do not support a significant association between variants in PPAR-encoding genes and SCZ, but suggest a necessity to explore the role of PPARD and PPARG in early SCZ phenotypes, specifically in females. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of atractylenolide on recurrent spontaneous abortion (RSA). Methods: The HTR-8/SVneo was established as an in vitro cell model of RSA. Cell viability and proliferation were determined using CCK8 and BrdU staining, while cell migration and invasion were determined by cell scratch and transwell assays. Results: Atractylenolide significantly increased cell viability, and enhanced the number of BrdU-positive cells of HTR-8/SVneo (p < 0.01). Atractylenolide also significantly promoted cell migration and invasion (p < 0.01), and increased protein expression of MMP-9, MMP-2, and N-cadherin, but reduced Ecadherin. Atractylenolide also increased the phosphorylation of ERK (p < 0.01). Conclusion: Atractylenolide enhances cell proliferation and migration of HTR-8/SVneo through activation of ERK signaling. Further studies using animal models are recommended to determine the protective role of atractylenolide against RSA, in vivo. [ABSTRACT FROM AUTHOR]

Two-dimensional nearest neighbor classification algorithm (2DNNC) is proposed for analyzing agriculture remote sensing data by combining matrix feature leaning and matrix-based dictionary learning. In the framework of 2DNNC, all hyperspectral feature vectors are transformed into matrix features by a set of nearest neighbor classifiers. The matrix features contain significantly discriminant information because of the label information from the set of nearest neighbor classifiers. Taking advantage of these matrix features, discriminant matrix dictionary is learned for classification by rank-1 matrices approximation. Experimental results on agriculture remote sensing data show the effectiveness and efficiency of the proposed algorithm on hyperspectral image classification. [ABSTRACT FROM AUTHOR]

Background: Acupuncture has been used in China to treat tinnitus for a long time. There is debate as to whether or not De Qi is a key factor in achieving the efficacy of acupuncture. However, there is no sufficient evidence obtained from randomized controlled trials to confirm the role of De Qi in the treatment of acupuncture for tinnitus. This study aims to identify the effect of De Qi for patients who receive acupuncture to alleviate tinnitus by a prospective, double-blind, randomized, sham-controlled trial. Methods and design: This study compares two acupuncture groups (with or without manipulation) in 292 patients with a history of subjective tinnitus. The trial will be conducted in the Teaching Hospital of Chengdu University of Traditional Chinese Medicine. In the study, the patients will be randomly assigned into two groups according to a computer-generated randomization list and assessed prior to treatment. Then, they will receive 5 daily sessions of 30 minutes each time for 4 consecutive weeks and undergo a 12-week follow-up phase. The administration of acupuncture follows the guidelines for clinical research on acupuncture (WHO Regional Publication, Western Pacific Series Number 15, 1995), and is performed double-blind by physicians well-trained in acupuncture. The measures of outcome include the subjective symptoms scores and quantitative sensations of De Qi evaluated by Visual Analog Scales (VAS) and the Chinese version of the 'modified' Massachusetts General Hospital Acupuncture Sensation Scale (C-MMASS). Furthermore, adverse events are recorded and analyzed. If any subjects are withdrawn from the trial, intention-to-treat analysis (ITT) and per-protocol (PP) analysis will be performed. Discussion: The key features of this trial include the randomization procedures, large sample and the standardized protocol to evaluate De Qi qualitatively and quantitatively in the treatment of acupuncture for tinnitus. The trial will be the first study with a high evidence level in China to assess the efficacy of De Qi in the treatment of tinnitus in a randomized, double-blind, sham-controlled manner. [ABSTRACT FROM AUTHOR]

Our understanding of plant responses to enhanced ultraviolet-B ( UV-B) radiation has improved over recent decades. However, research on cryptogams is scarce and it remains controversial whether UV-B radiation causes changes in physiology related to photosynthesis. To investigate the effects of supplementary UV-B radiation on photosynthesis and chloroplast ultrastructure in Bryum argenteum Hedw., specimens were cultured for 10 days under four UV-B treatments (2.75, 3.08, 3.25 and 3.41 W m-2), simulating depletion of 0% (control), 6%, 9% and 12% of stratospheric ozone at the latitude of Shapotou, a temperate desert area of northwest China. Analyses showed malondialdehyde content significantly increased, whereas chlorophyll (Chl) fluorescence parameters and Chl contents decreased with increased UV-B intensity. These results corresponded with changes in thylakoid protein complexes and chloroplast ultrastructure. Overall, enhanced UV-B radiation leads to significant decreases in photosynthetic function and serious destruction of the chloroplast ultrastructure of B. argenteum. The degree of negative influences increased with the intensity of UV-B radiation. These results may not only provide a potential mechanism for supplemental UV-B effects on photosynthesis of moss crust, but also establish a theoretical basis for further studies of adaptation and response mechanisms of desert ecosystems under future ozone depletion. [ABSTRACT FROM AUTHOR]

Background: Catgut implantation at acupoints has been used in China to treat allergic rhinitis (AR) for a long time. However, its efficacy and safety in the treatment of AR is controversial due to the poor quality of the clinical trial of this therapy. This study aims to identify whether catgut implantation at acupoints is indeed an effective and safe treatment for patients with persistent or intermittent allergic rhinitis (PER or IAR) by comparing with sham catgut implantation treatment. Methods and design: This study compares real versus sham catgut implantation at acupoints in 242 patients with a history of PER or IAR and with a positive skin prick test (SPT). The trial will be conducted in the Teaching Hospital of Chengdu University of Traditional Chinese Medicine. In the study, patients will be randomly assigned by computer-generated randomization list into two groups and assessed prior to treatment. Then, they will receive two sessions of treatments (once per 2 weeks) for 4 consecutive weeks and have a follow-up phase of 12 weeks. The administration of catgut implantation (or sham-control) at acupoints follows the guidelines for clinical research on acupuncture (WHO Regional Publication, Western Pacific Series No.15, 1995), and is performed double-blindly by a well-trained physician in acupuncture. The main outcome measures include the primary and secondary indicators. Primary indicators are subjective symptoms scores evaluated by visual analogue scales (VAS) and Rhinoconjunctivitis Quality of Life Questionnaires (RQLQ). The secondary indicators are the results of laboratory examinations, such as serum allergen-specific IgE, nasal inflammatory cells counts (mast cells, eosinophils, and T cells) and nitric oxide concentration in nasal excretion. The use of anti-allergic medication will also be recorded as one of the secondary indicators. Furthermore, adverse events will be recorded and analyzed. If any participants withdraw from the trial, intention-to-treat analysis (ITT) and per-protocol (PP) analysis will be performed. Discussion: The important features of this trial include the randomization procedures, large sample, and a standardized protocol of catgut implantation at acupoints. This trial will be the first study with a high evidence level in China in order to assess the efficacy and safety of catgut implantation at acupoints in treatment of AR following a randomized, double-blind sham-controlled method. [ABSTRACT FROM AUTHOR]

In this paper, we present an in-depth study of two collaborative-localization methods, called the multidimensional scaling (MDS) and maximum-likelihood estimator (MLE), for wireless sensor networks. From theoretical analysis, it is shown that MLE is more appropriate than MDS, given the underlying assumption of statistical signal models of the received-signal-strength-based localization problem. We also show that MDS can approximately achieve asymptotic efficiency with appropriate weighting schemes in some scenarios. From extensive simulation results, it is noted that the nonlinear least square algorithms that are commonly used to determine MLE are not as efficient as the iterative MDS algorithms. Thus, we propose a new integrated method MDS-MLE to effectively benefit from the strength of both methods. In the new method, MDS is used as an initialization method for MLE. With the solution of MDS as an initial value, MLE converges much faster and achieves significantly better performance than with random initial values. Superior performance of the new method is clearly demonstrated through simulation results. The effects of the deployment density of sensor nodes and reference nodes (RNs), as well as the deployment structure of RNs, are also studied through various simulations. [ABSTRACT FROM AUTHOR]

Using time of arrival (TOA) to determine the distance between the transmitter and the receiver is the most popular technique for accurate indoor positioning. The accuracy of measuring the distance using this method is sensitive to the bandwidth of the system and the multipath condition between the wireless terminal and the access point. In general, as the bandwidth increases beyond a certain value, it is expected that the measured TOA error approaches zero. However, for the so-called undetected direct path (UDP) conditions, the system exhibits substantially high distance measurement errors that cannot be eliminated with the increase in the bandwidth of the system. In this paper, we provide an analysis of the behavior of superresolution and traditional TOA estimation algorithms in line-of-sight (LOS), non-LOS, and UDP conditions in indoor areas. The analysis is based on wideband frequency-domain measurements of the indoor radio channel propagations in several indoor areas, with special attention to the UDP conditions. [ABSTRACT FROM AUTHOR]

A USEPA, procedure, ISCLT3 (Industrial Source Complex Long-Term), was applied to model the spatial distribution of polycyclic aromatic hydrocarbons (PAHs) emitted from various sources including coal, petroleum, natural gas, and biomass into the atmosphere of Tianjin, China. Benzo[a]-pyrene equivalent concentrations (BaPeq) were calculated for risk assessment. Model results were provisionally validated for concentrations and profiles based on the observed data at two monitoring stations. The dominant emission sources in the area were domestic coal combustion, coke production, and biomass burning. Mainly because of the difference in the emission heights, the contributions of various sources to the average concentrations at receptors differ from proportions emitted. The shares of domestic coal increased from ~43% at the sources to 56% at the receptors, while the contributions of coking industry decreased from ~23% at the sources to 7% at the receptors. The spatial distributions of gaseous and particulate PAHs were similar, with higher concentrations occurring within urban districts because of domestic coal combustion. With relatively smaller contributions, the other minor sources had limited influences on the overall spatial distribution. The calculated average BaPeq value in air was 2.54 ± 2.87 ng/m³ on an annual basis. Although only 2.3% of the area in Tianjin exceeded the national standard of 10 ng/m³, 41% of the entire population lives within this area. [ABSTRACT FROM AUTHOR]

Discusses the issues related to indoor geolocation science that are needed for design and performance evaluation of emerging wireless indoor geolocation systems. Channel characteristics for indoor geolocation; Location sensing techniques; Discussion of positioning algorithms.

Purpose: To examine the effect of mangiferin on insulin resistance (IR) in a rat polycystic ovary syndrome (PCOS) model. Methods: The rat PCOS model was established via subcutaneous injection of 6 mg/kg of dehydroepiandrosterone (DHEA), and mangiferin was orally administered. Body and ovarian weights were recorded. Serum levels of glucose, insulin, and related inflammatory cytokines were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay, while the expression levels of key proteins were analyzed by western blotting. Results: DHEA significantly increased ovarian weight and the ratio of ovarian weight/body weight (p < 0.001), while mangiferin treatment decreased them (p < 0.001). Mangiferin also lowered DHEA-induced enhancements in serum glucose and insulin levels (p < 0.001). The mRNA and, expression and concentrations of inflammatory cytokines (interleukin-6(IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α)) were also significantly reduced by mangiferin treatment (p < 0.001). Furthermore, mangiferin suppressed phosphorylation of nuclear factor-kappa B (NF-kB) but increased the phosphorylation of protein kinase B (AKT, p < 0.001). Conclusion: These results reveal that mangiferin not only decreases inflammatory cytokine levels by regulating NF-kB signaling pathway but also ameliorates IR in a rat PCOS model via regulating AKT signaling pathway. Thus, mangiferin is a potential therapeutic strategy for the management of PCOS. [ABSTRACT FROM AUTHOR]

Background and Aims: Biocrusts cover approximately 30% of the global dryland surface area, constituting a crucial atmosphere–soil interface. Bacteria living at this interface participate in almost all biogeochemical cycling processes that may profoundly alter soil and ecosystem multifunctionality and speed up ecosystem restoration. However, the successional dynamics of bacterial communities in both biocrusts and subsoil remain largely unclear. Methods: This study used α and β diversity assessments and molecular ecological networks to reveal the bacterial community succession in biocrusts and subsoil along a 65-year succession sequence (a succession of biocrust types ranging from cyanobacteria to lichens to mosses) on the southeastern edge of the Tengger Desert. Results: Our results showed that the bacterial α and β diversity and network complexity in the biocrusts and subsoil increased with succession. In the process of succession, there were distinct differences observed in bacterial community diversity and network complexity and stability between biocrusts and subsoil. In particular, the subsoil bacterial network properties, including nodes, links, average links per node, average clustering coefficient, connectance and relative modularity, were significantly higher than those of biocrust in late succession. Based on piecewise SEM, we also found that succession, soil physicochemical conditions, and biocrust bacterial community composition were the strongest direct drivers of subsoil bacterial community composition. The plant communities and biocrust bacterial community composition directly drove the network complexity and stability of the subsoil bacterial community. Conclusion: Our findings indicate that under the cover and protection of the biocrust layer, the diversity of the bacterial community in the subsoil layer increased more obviously, and the network was more complex and stable. This may emphasize the important roles of biocrusts as mediators of soil microbial communities. [ABSTRACT FROM AUTHOR]

When shortest path algorithm be used in real time road network monitoring system, the time complexity of the algorithm is becoming the bottleneck of the system. the paper proposes a solution to improve the shortest path algorithm. By making use of the k-ary-reverse tree and locality principle, this improved algorithm keeps the data operation, in priority queue, be localized in a small range. So the time complexity of this improved shortest path algorithm is optimized from O(nlog2n) to $$O(k\times n)$$ ; the parameter k denotes the average count of adjacency edges to each vertex, and n denotes the total count of vertexes in the network. Note that, the parameter k mainly depends on the edges density in the network. Generally speaking, the mean value of parameter k is not more than 4 in the road network, i.e. the time complexity of the improved algorithm is optimized from O(nlog2n) to O( n) in the road network. So the paper makes a conclusion that there is a linear correlation between the time complexity and the vertexes count n in the improved algorithm. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSNs) have great potential to revolutionize many science and engineering domains. We present a novel environmental monitoring system with a focus on overall system architecture for seamless integration of wired and wireless sensors for long-term, remote, and near-real-time monitoring. We also present a unified framework for sensor data collection, management, visualization, dissemination, and exchange, conforming to the new Sensor Web Enablement standard. Some initial field testing results are also presented. The monitoring system is being integrated into the Texas Environmental Observatory infrastructure for long-term operation. As part of the integrated system, a new WSN-based soil moisture monitoring system is developed and deployed to support hydrologic monitoring and modeling research. This work represents a significant contribution to the empirical study of the emerging WSN technology. We address many practical issues in real-world application scenarios that are often neglected in the existing WSN research. [ABSTRACT FROM AUTHOR]

The spatial and temporal patterns of pedogenesis on stabilized dunes at Shapotou, northwestern China, were studied on the time sequences of 0, 18, 35 and 43 years. The spatial pattern of soil formation was estimated by measuring the thickness of accumulated sand fractions on the stabilized dune surface and by analyzing the characteristics and properties of soil. The results showed that the environment of soil formation and circulation of soil material were influenced in the processes of shifting-sand fixation, and the mean soil particle size changed from >0.2 to <0.08 mm in 0–20 cm soil depth with the succession from cultivated plants to natural vegetation. The capacity of available soil water increased fivefold. Deep infiltration of water in soil no longer occurred due to the increase in soil water capacity and the change of redistribution of soil water in profiles. Soil microorganisms evolved from simple to complex. Interaction of these processes obviously brought about accumulation of soil fertility, evolution of soil profiles and development of the profiles towards aripsamments. The difference of micro-topography is closely related to redistribution of material and energy in soil formation. [Copyright &y& Elsevier]

A minimax optimization approach has been previously contributed to extend the conventional two-dimensional (2-D) carrierless amplitude/phase modulation (CAP) scheme to three-dimensional (3-D). In this paper, we show that there is no guarantee of spectral efficiency by this approach. This is a potentially fatal design flaw which results in the 3-D CAP system being exceptionally susceptible to noise, even if it is of very small magnitude, for example, quantization noise. A new minimax approach is, thus, contributed to design bandwidth-efficient 3-D CAP waveforms which are more robust and useful for very high-speed digital subscriber loop applications and high-speed LAN systems. Some design examples are provided. [ABSTRACT FROM AUTHOR]

Shapotou Desert Research Station is located at the southeast edge of Tengger Desert in China. Shapotou sand dunes have been vegetated to stabilize them. The vegetated dunes have been completely covered by a natural crust. Rain infiltration was reduced by 36 % to 74 % on the crusted site while there was no reduction of rain infiltration on the sandy site. The infiltration rate was positively correlated with total rainfall and negatively correlated with rain intensity. Runoff on the crusted site provided water for vegetation growth in the hollows between sand dunes. The crust significantly impeded increased soil moisture. To increase soil moisture in the surface 40 cm layer, rainfall had to be above 8.5 mm on the slopes of sand dunes on the crust site, and increased with rain intensity. In the Shapotou area, the amount of rainfall that vegetation on slopes of sand dunes could utilize, was reduced to about 40 mm per year by the crust, although the mean annual precipitation was approx imately 180 mm. It is expected that vegetation cover will continuously degrade in the future. To maintain vegetative cover adequate to stabilize the active sand dune, it was necessary to break part of the crust at slope of sand dune. [ABSTRACT FROM AUTHOR]

Despite evidence from experimental grasslands that plant diversity increases biomass production and soil organic carbon (SOC) storage, it remains unclear whether this is true in natural ecosystems, especially under climatic variations and human disturbances. Based on field observations from 6,098 forest, shrubland, and grassland sites across China and predictions from an integrative model combining multiple theories, we systematically examined the direct effects of climate, soils, and human impacts on SOC storage versus the indirect effects mediated by species richness (SR), aboveground net primary productivity (ANPP), and belowground biomass (BB). We found that favorable climates (high temperature and precipitation) had a consistent negative effect on SOC storage in forests and shrublands, but not in grasslands. Climate favorability, particularly high precipitation, was associated with both higher SR and higher BB, which had consistent positive effects on SOC storage, thus offsetting the direct negative effect of favorable climate on SOC. The indirect effects of climate on SOC storage depended on the relationships of SR with ANPP and BB, which were consistently positive in all biome types. In addition, human disturbance and soil pH had both direct and indirect effects on SOC storage, with the indirect effects mediated by changes in SR, ANPP, and BB. High soil pH had a consistently negative effect on SOC storage. Our findings have important implications for improving global carbon cycling models and ecosystem management: Maintaining high levels of diversity can enhance soil carbon sequestration and help sustain the benefits of plant diversity and productivity. [ABSTRACT FROM AUTHOR]

A dual-polarised, quadruple-ridged horn antenna with a coaxial feed operating over the frequency range of 75-500 MHz is presented. For the reduction of the antenna weight, a composite sandwich structure is used to build the antenna, which comprises solid aluminium and honeycomb materials. An adjustable shorting plate is put at the bottom of the antenna to prevent the occurrence of singularities created by standing waves. A Teflon plate is put at the centre position among the four symmetry ridges to mechanically support the huge antenna structure without breaking the symmetry of the ridges, leading to good electrical performance. Simulation and measured results are presented. [ABSTRACT FROM AUTHOR]

Many studies have shown that changes in nitrogen (N) availability affect the diversity and composition of soil microbial community in a variety of terrestrial systems, but less is known about the responses of microbes specific to biological soil crusts (BSCs) to increasing N additions. After seven years of field experiment, the bacterial diversity in lichen-dominated crusts decreased linearly with increasing inorganic N additions (ambient N deposition; low N addition, 3.5 g N m−2 y−1; medium N addition, 7.0 g N m−2 y−1; high N addition, 14.0 g N m−2 y−1), whereas the fungal diversity exhibited a distinctive pattern, with the low N-added crust containing a higher diversity than the other crusts. Pyrosequencing data revealed that the bacterial community shifted to more Cyanobacteria with modest N additions (low N and medium N) and to more Actinobacteria and Proteobacteria and much less Cyanobacteria with excess N addition (high N). Our results suggest that soil pH, together with soil organic carbon (C), structures the bacterial communities with N additions. Among the fungal communities, the relative abundance of Ascomycota increased with modest N but decreased with excess N. However, increasing N additions favored Basidiomycota, which may be ascribed to increases in substrate availability with low lignin and high cellulose contents under elevated N conditions. Bacteria/fungi ratios were higher in the N-added samples than in the control, suggesting that the bacterial biomass tends to dominate over that of fungi in lichen-dominated crusts after N additions, which is especially evident in the excess N condition. Because bacteria and fungi are important components and important decomposers in BSCs, the alterations of the bacterial and fungal communities may have implications in the formation and persistence of BSCs and the cycling and storage of C in desert ecosystems. [ABSTRACT FROM AUTHOR]

In desert ecosystems, plant growth and nutrient uptake are restricted by availability of soil nitrogen (N) and phosphorus (P). The effects of both climate and soil nutrient conditions on N and P concentrations among desert plant life forms (annual, perennial and shrub) remain unclear. We assessed leaf N and P levels of 54 desert plants and measured the corresponding soil N and P in shallow (0-10 cm), middle (10-40 cm) and deep soil layers (40-100 cm), at 52 sites in a temperate desert of northwest China. Leaf P and N5P ratios varied markedly among life forms. Leaf P was higher in annuals and perennials than in shrubs. Leaf N and P showed a negative relationship with mean annual temperature (MAT) and no relationship with mean annual precipitation (MAP), but a positive relationship with soil P. Leaf P of shrubs was positively related to soil P in the deep soil. Our study indicated that leaf N and P across the three life forms were influenced by soil P. Deep-rooted plants may enhance the availability of P in the surface soil facilitating growth of shallow-rooted life forms in this N and P limited system, but further research is warranted on this aspect. [ABSTRACT FROM AUTHOR]

Land plants have developed a cuticle preventing uncontrolled water loss. Here we report that an ATP-binding cassette (ABC) subfamily G (ABCG) full transporter is required for leaf water conservation in both wild barley and rice. A spontaneous mutation, eibi1.b, in wild barley has a low capacity to retain leaf water, a phenotype associated with reduced cutin deposition and a thin cuticle. Map-based cloning revealed that Eibi1 encodes an HvABCG31 full transporter. The gene was highly expressed in the elongation zone of a growing leaf (the site of cutin synthesis), and its gene product also was localized in developing, but not in mature tissue. A de novo wild barley mutant named "eibi1.c," along with two transposon insertion lines of rice mutated in the ortholog of HvABCG31 also were unable to restrict water loss from detached leaves. HvABCG31 is hypothesized to function as a transporter involved in cutin formation. Homologs of HvABCG31 were found in green algae, moss, and lycopods, indicating that this full transporter is highly conserved in the evolution of land plants. [ABSTRACT FROM AUTHOR]

Abstract: Renewable energy is the inevitable choice for sustainable economic growth, for the harmonious coexistence of human and environment as well as for the sustainable development. Government support is the key and initial power for developing renewable energy. In this article, an overall review has been conducted on renewable energy development policy (including laws and regulations, economic encouragement, technical research and development, industrialized support and government model projects, etc.) in China. On this basis, a systematic analysis has been conducted on the disadvantages of renewable energy development policy. On the point of long-term effective system for renewable energy development, a series of policy advice has been offered, such as strengthening the policy coordination, enhancing regional policy innovation, echoing with clean development mechanism, implementing process management, constructing market investment and financing system. It is expected that the above advices could be helpful to ever-improvement of renewable energy development policy. [Copyright &y& Elsevier]

An orthogonal L16(45) design of combined effects of the five factors, nitrogen (N) fertilizer, phosphorus (P) fertilizer, potassium (K) fertilizer, organic manure, and water on the spring wheat (Triticum aestivum L.) yield, has been conducted for three years on Orthic Anthrosols at Shapotou in the southeast margin of the Tengger Desert. The results show that N and P fertilizers have significantly influenced spring wheat yield, that characterized by increase of the yields by increasing applies of N and P fertilizers. If the application rates of N and P fertilizers reach 200 kg ha−1 and 35.6 kg ha−1, the spring wheat yield was the highest. Potassium fertilizer has a less influence on spring wheat yield, suggesting that it is unsuitable to use it in the fertile Anthrosols in the loess region. Irrigation intensity is also a key factor affecting crop production in this arid region. The irrigation intensity in the experimental range is directly proportional to the wheat yield, but lower irrigation intensity has larger yield-increasing efficiency than that of higher irrigation intensity. In addition, the influences of NPK fertilizers on the nutrient contents in soil and spring wheat straw, and the interactions between various fertilizers and water are analyzed. The optimal water–fertilizer combination and maximum production potential were determined by establishing a water–fertilizer–yield model. [ABSTRACT FROM AUTHOR]

Spectroscopic ellipsometry (SE) is utilized to characterize the vanadium oxide (VOx)–single walled carbon nanotube (SWCNT) composite films prepared by sol–gel. Five Tauc–Lorentz oscillators model is employed to describe the dispersions in the optical responses of VOx and VOx–SWCNT thin films. Results reveal that if the SWCNT concentration in the composite film is increased, the refractive index is decreased, while the extinction coefficient is increased. Moreover, higher SWCNT content leads to lower optical band gap (Eg) but larger localized state (Ee). Interestingly, both Eg and Ee values reach saturated at a SWCNT content of ~8 wt%. Particularly, the peak transition energies of the 5 Tauc–Lorentz oscillators have been assigned to the specific transitions according to the band structures of VOx. This work reveals the feasibility of investigating the optical properties and microstructures of VOx–SWCNT composite films by SE. These experimental results will be helpful for better understanding the VOx–SWCNT composite films, and promoting future characterizations of other SWCNT-based composites by SE. [ABSTRACT FROM AUTHOR]