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The effects of grazing on natural grasslands' plant composition, diversity, and productivity depend on the intensity of grazing. Besides grazing intensity, animal composition is also important. However, whether and how sheep grazing intensity affects the temporal biomass stability of plant communities is unclear. Here, we conducted a 5‐year grazing experiment to evaluate the effects of four grazing intensities on community biomass stability and the underlying mechanisms. Our results showed that the higher grazing intensity significantly decreased community biomass stability, community‐wide asynchrony, functional groups asynchrony, dominant species stability, and species dominance, but did not affect species richness. The results of structural equation modeling revealed that grazing decreased community biomass stability by decreasing dominant species stability and community‐wide asynchrony, which was attributable to the reduction in plant functional group asynchrony. Our results highlight the importance of functional group composition and dynamics in predicting the changes in community function in sheep grazing grassland ecosystems. Under continuous seasonal grazing conditions, the sustainable function and human services of grasslands in the agropastoral ecotone might decrease in the future. [ABSTRACT FROM AUTHOR]

The fraction of net primary productivity (NPP) allocated to belowground organs (fBNPP) in grasslands is a critical parameter in global carbon cycle models; moreover, understanding the effect of precipitation changes on this parameter is vital to accurately estimating carbon sequestration in grassland ecosystems. However, how fBNPP responds to temporal precipitation changes along a gradient from extreme drought to extreme wetness, remains unclear, mainly due to the lack of long‐term data of belowground net primary productivity (BNPP) and the fact that most precipitation experiments did not have a gradient from extreme drought to extreme wetness. Here, by conducting both a precipitation gradient experiment (100–500 mm) and a long‐term observational study (34 years) in the Inner Mongolia grassland, we showed that fBNPP decreased linearly along the precipitation gradient from extreme drought to extreme wetness due to stronger responses in aboveground NPP to drought and wet conditions than those of BNPP. Our further meta‐analysis in grasslands worldwide also indicated that fBNPP increased when precipitation decreased, and the vice versa. Such a consistent pattern of fBNPP response suggests that plants increase the belowground allocation with decreasing precipitation, while increase the aboveground allocation with increasing precipitation. Thus, the linearly decreasing response pattern in fBNPP should be incorporated into models that forecast carbon sequestration in grassland ecosystems; failure to do so will lead to underestimation of the carbon stock in drought years and overestimation of the carbon stock in wet years in grasslands. [ABSTRACT FROM AUTHOR]

Soil dissolved organic matter (DOM) plays a critical role in regulating the cycling of terrestrial biogeochemistry. However, the influence mechanisms of nitrogen (N) addition on soil DOM concentration are not well understood at the regional scale. We performed a meta‐analysis of 1004 paired observations from 115 literature to explore how N addition affected the soil DOM concentration, including dissolved organic carbon (DOC) and nitrogen (DON), in China. Overall, N addition markedly stimulated the soil DOC and DON concentrations by 5.2% and 33.1%, respectively. This implied that the stimulation by increased N availability than the suppression by decreased soil pH played a more important role in the soil DOM concentration under N addition. The N addition level showed a significantly positive correlation with the soil DOC and DON concentrations under N addition. The N addition influence on soil DOC concentration was decreased along with the increase in initial soil total nitrogen (TN). This demonstrated the microbial N mining theory in the low N soils and the stoichiometric decomposition theory in the high N soils at the regional scale. The mean annual precipitation (MAP) potentially facilitated the leaching out of soil DON and displayed a negative impact on the soil DON concentration under N addition. The increased soil depth and initial soil pH depressed the soil DOC concentration whereas stimulated the soil DON concentration under N addition. This indicated that DOC mostly accumulated in the top soil and DON largely leached to the deep soil. And the initial soil pH with high value perhaps promoted the uptake of DOC for microbes and the solubility of DON, and thus resulted in the opposite influences on the soil DOC and DON concentrations. Our study provided a mechanistic understanding on N addition influence on the C and N dynamics of terrestrial ecosystem at the regional scale. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to estimate the safety and efficacy of spray cryotherapy (SCT) in patients with chronic obstructive pulmonary disease (COPD). Methods: We recruited patients aged 40–80 years with a confirmed diagnosis of COPD without serious complications (defined as two consecutive years of chronic cough and cough for at least 3 months with lung function forced expiratory volume in 1 s [FEV1]/forced vital capacity [FVC] < 70% after inhaled bronchodilators and Global Initiative for Chronic Obstructive Lung Disease [GOLD] grade II–IV). The safety of this study was assessed by incidence of adverse events, and the efficacy was evaluated by St. George's Respiratory Questionnaire (SGRQ), COPD assessment test (CAT), Leicester Cough Questionnaire (LCQ) and changes in exercise capacity, histomorphology and lung function. Results: Eight patients eventually received three complete sessions of SCT, each lasting 41.10 ± 19.72 min. No adverse complications were recorded within 3 months after SCT. Clinically meaningful improvements in SGRQ, CAT, LCQ and exercise capacity were observed at 3 months after SCT: −15.75 ± 6.76 (95% confidence interval [CI] 10.10−21.40; p <.001), −6.88 ± 3.91 (95% CI 3.61−10.14; p =.002), −18.13 ± 13.81 (95% CI 6.58−29.67; p =.008) and 72.75 ± 33.11 (95% CI −100.43 to −45.07; p <.001), respectively. The density of airway epithelial goblet cells per unit area was significantly reduced (p <.05), and lung function parameters such as ∆FVC, ∆FEV1 and ∆ peak expiratory flow (∆PEF) were improved (p =.007,.021 and.012). Conclusions: SCT is a safe and effective strategy to provide a better quality of life for COPD patients. [ABSTRACT FROM AUTHOR]

As precipitation (PPT) regimes are becoming more extreme worldwide, the inter‐annual variation in PPT amount at a given location is becoming greater than ever before. Yet, our understanding of grassland responses to extreme drought and wet years, as well as the pattern of the relationship between PPT and above‐ground net primary productivity (ANPP) along a PPT gradient from extreme drought to extreme wetness scenarios, remains unclear, hampering accurate forecasting of the grassland feedbacks to future PPT changes.We addressed this research gap by a 4‐year, multi‐level PPT gradient experiment that included PPT amounts simulating extremely dry and wet years in combination with a long‐term (40 years) observational study in a grassland ecosystem.We found that the ANPP reductions due to extreme droughts were greater than the magnitude of positive responses to extreme wet years. The PPT‐ANPP relationship along the gradient of PPT followed a negative asymmetric (concave‐down) pattern. We identified the major mechanisms for this pattern were a shift in primary limiting resource for ANPP from water to nitrogen with increasing PPT and different responses of the plant functional groups presented in the community. With the increase of PPT from extremely low to extremely high levels, the relative abundance of forbs increased, while that of grasses decreased and annuals was not significantly affected.This study illustrates how a grassland responded to PPT extremes and highlights the role of shifts in resource limitation in affecting the PPT‐ANPP relationship. The negative asymmetric pattern suggests that the reduction of ANPP in extremely drought years cannot be mitigated by its positive response to extremely wet years. Thus, to accurately forecast future ecosystem feedback to climate change, we should take into account the negative asymmetric feature of the ecosystem response to stronger climate variation, as well as recognize that the resource limitations will be fundamentally altered by increasing frequency and intensity of climate extremes in the future. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Acquired digestive‐respiratory tract fistulas occur with abnormal communication between the respiratory tract and digestive tract caused by a variety of benign or malignant diseases, leading to the alimentary canal contents in the respiratory tract. Although various departments have been actively exploring advanced fistula closure techniques, including surgical methods and multimodal therapy, some of which have gotten good clinical effects, there are few large‐scale evidence‐based medical data to guide clinical diagnosis and treatment. The guidelines update the etiology, classification, pathogenesis, diagnosis, and management of acquired digestive‐respiratory tract fistulas. It has been proved that the implantation of the respiratory and digestive stent is the most important and best treatment for acquired digestive‐respiratory tract fistulas. The guidelines conduct an in‐depth review of the current evidence and introduce in detail the selection of stents, implantation methods, postoperative management and efficacy evaluation. [ABSTRACT FROM AUTHOR]

Determining the abundance of N isotope (δ15N) in natural environments is a simple but powerful method for providing integrated information on the N cycling dynamics and status in an ecosystem under exogenous N inputs. However, whether the input of different N compounds could differently impact plant growth and their 15N signatures remains unclear. Here, the response of 15N signatures and growth of three dominant plants (Leymus chinensis, Carex duriuscula, and Thermopsis lanceolata) to the addition of three N compounds (NH4HCO3, urea, and NH4NO3) at multiple N addition rates were assessed in a meadow steppe in Inner Mongolia. The three plants showed different initial foliar δ15N values because of differences in their N acquisition strategies. Particularly, T. lanceolata (N2‐fixing species) showed significantly lower 15N signatures than L. chinensis (associated with arbuscular mycorrhizal fungi [AMF]) and C. duriuscula (associated with AMF). Moreover, the foliar δ15N of all three species increased with increasing N addition rates, with a sharp increase above an N addition rate of ~10 g N m−2 year−1. Foliar δ15N values were significantly higher when NH4HCO3 and urea were added than when NH4NO3 was added, suggesting that adding weakly acidifying N compounds could result in a more open N cycle. Overall, our results imply that assessing the N transformation processes in the context of increasing global N deposition necessitates the consideration of N deposition rates, forms of the deposited N compounds, and N utilization strategies of the co‐existing plant species in the ecosystem. [ABSTRACT FROM AUTHOR]

Miniaturized micro‐spectrometers with high‐resolution and large‐bandwidth are of great importance for on‐site spectroscopic analysis applications. Here, a novel high‐resolution and large‐bandwidth micro‐spectrometer is presented, which operates at dual‐wavelength band by utilizing a (N + 3) × (N + 3) arrayed waveguide grating (AWG) and three dual‐wavelength grating couplers on a silicon‐on‐insulator (SOI) platform. The AWG working in a counter‐propagating manner can be viewed as two 3 × N AWGs, and the dual‐wavelength grating coupler acts as a prefilter. Three time‐division‐multiplexing inputs with wavelength spacings of 4/3 times that of N output waveguides are employed to improve the resolution of the micro‐spectrometer. Combining the corresponding outputs of three inputs, a micro‐spectrometer with resolution enhanced to one‐third wavelength spacing of output waveguides and effective channel number enlarged to 3 × (N − 2) is achieved, only using N output channels at each wavelength band. A micro‐spectrometer with 63 effective channels and resolutions of 0.5 and 0.442 nm at 1550 and 1310 nm bands, respectively, is experimentally demonstrated. The footprint of the fabricated micro‐spectrometer is 2 × 0.81 mm2, with measured on‐chip losses of −4.6 to −2.8 dB (−7.0 to −3.1 dB) and crosstalk levels < −18.5 (−16.8) dB at the 1550 (1310) nm band. [ABSTRACT FROM AUTHOR]

Soil net nitrogen (N) mineralization is a key biogeochemical process influencing plant available N and net primary productivity in terrestrial ecosystems. However, the spatial variations and controlling factors of soil net N mineralization (RPNM) in arid and semi‐arid grasslands are less studied and unclear.In this study, we investigated the soil RPNM by performing a laboratory incubation experiment. Soil samples were collected from 30 sites in three east–west transects on the Inner Mongolia Plateau (MP), Loess Plateau (LP) and Tibetan Plateau (TP) along a 3200 km arid and semi‐arid grassland gradient, with each transect containing three different grassland types (meadow steppe [MS], typical steppe [TS] and desert steppe [DS], respectively).Results showed that the average RPNM values ranged from −0.37 to 1.29 mg N kg−1 day−1, with a significantly lower RPNM found in the DS (0.08 ± 0.01 mg N kg−1 day−1) compared with those in the MS (0.30 ± 0.03 mg N kg−1 day−1) and in the TS (0.33 ± 0.03 mg N kg−1 day−1) in the MP and LP transects (p < 0.05). This difference could be explained by variations in climatic and soil factors, such as hydrothermal index (HT), the soil pH, soil organic matter (SOM) and precipitation. However, no significant differences in RPNM were found among different grassland types in the TP transect, possibly due to the similarly low microbial activity, as indicated by the microbial biomass carbon values. Across all three grassland transects, HT, SOM and microbial variables were the major factors controlling RPNM, which together explained 20.7% of the variation in RPNM. Further structural equation model analysis indicated HT was an integral predictor of RPNM, directly or indirectly via SOM, under different conditions of precipitation and temperature.Our findings provide field evidence and parameters for biogeochemical cycling to better predict future N transformation processes under changing precipitation and temperature regimes across a wide range of arid and semi‐arid grassland ecosystems. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Aim: The contemporary coexistence theory suggests that species pool, environmental filtering, dispersal assembly processes, ecological drift and biotic interactions collectively determine the β‐diversity of communities. However, we know little about the biogeographical patterns of the β‐diversity of microbial communities harbouring the alkaline phosphatase phoD gene (phoD communities, hereafter) and whether these mechanisms are all‐important in shaping phoD communities' β‐diversity in natural steppe ecosystems. Location: Northern Hemisphere steppes. Time period: July to August 2018. Major taxa studied: Alkaline phosphatase (phoD gene) encoding community. Methods: Using the high throughput amplicon sequencing method, soil phoD communities were comparatively studied along three representative regions of the Northern Hemisphere steppes, namely the Qinghai‐Tibetan Plateau, Inner Mongolian Plateau and the Loess Plateau. Each region harbours three types of steppes (habitats): meadow, typical and desert steppes. Results: We observed significantly higher phoD β‐diversity in the Qinghai‐Tibetan than in the Loess and Inner Mongolian Plateaus and significantly lower β‐diversity in the typical steppes than in other steppe types. The decay rates of phoD β‐diversity with geographical distance varied in different steppe regions and types. The phoD β‐diversity was not significantly influenced by species pool; instead, environmental filtering, dispersal assembly processes, ecological drift and biotic interactions jointly shaped the β‐diversity patterns. The β‐deviation variations (β‐diversity excluding the effects of species pool) were influenced by spatial and environmental factors and biotic interactions, among which soil pH was the key environmental determinant. The soil pH driving β‐diversity mechanism was steppe region and habitat specific. Main conclusions: The biogeographical patterns of phoD β‐diversity were mainly driven by local community assembly processes in the Northern Hemisphere steppes. [ABSTRACT FROM AUTHOR]

Summary: Lake and adjoining river ecosystems are ecologically and economically valuable and are heavily threatened by anthropogenic activities. Determining the inherent capacity of ecosystems for polycyclic aromatic hydrocarbon (PAH) biodegradation can help quantify environmental impacts on the functioning of ecosystems, especially on that of the microbial community. Here, PAH biodegradation potential was compared between sediments collected from a lake bay (LS) and an adjoining river (RS) ecosystem. Microbial community composition, function, and their co‐occurrence patterns were also explored. In the RS, the biodegradation rates (KD) of pyrene or PAH were almost two orders of magnitude higher than those in the LS. Sediment functional community structure and network interactions were dramatically different between the LS and RS. Although PAH degradation genes (p450aro, quinoline, and qorl) were detected in the LS, the community activity of these genes needed to be biostimulated for accelerated bioremediation. In contrast, functional communities in the RS were capable of spontaneous natural attenuation of PAH. The degradation of PAH in the RS also required coordinated response of the complex functional community. Taken together, elucidating functions and network interactions in sediment microbial communities and their responses to environmental changes are very important for the bioremediation of anthropogenic toxic contaminants. [ABSTRACT FROM AUTHOR]

Mitochondria, chloroplasts and several species of bacteria have outer membrane proteins (OMPs) that perform many essential biological functions. The β‐barrel assembly machinery (BAM) complex is one of the OMPs of Borrelia burgdorferi, the pathogenic spirochete that causes Lyme disease, and its BamA component (BbBamA) includes a C‐terminal β‐barrel domain and five N‐terminal periplasmic polypeptide‐transport‐associated (POTRA) domains, which together perform a central transport function. In the current work, the production, crystallization and X‐ray analysis of the three N‐terminal POTRA domains of BbBamA (BbBamA‐POTRA P1–P3; residues 30–273) were carried out. The crystals of BbBamA‐POTRA P1–P3 belonged to space group P21, with unit‐cell parameters a = 45.353, b = 111.538, c = 64.376 Å, β = 99.913°. The Matthews coefficient was calculated to be 2.92 Å3 Da−1, assuming the presence of two molecules per asymmetric unit, and the corresponding solvent content was 57.9%. Owing to the absence of an ideal homology model, numerous attempts to solve the BbBamA‐POTRA P1–P3 structure using molecular replacement (MR) failed. In order to solve the structure, further trials using selenomethionine derivatization are currently being carried out. [ABSTRACT FROM AUTHOR]

Soil net nitrogen mineralization rate (Nmin), which is critical for soil nitrogen availability and plant growth, is thought to be primarily controlled by climate and soil physical and/or chemical properties. However, the role of microbes on regulating soil Nmin has not been evaluated on the global scale. By compiling 1565 observational data points of potential net Nmin from 198 published studies across terrestrial ecosystems, we found that Nmin significantly increased with soil microbial biomass, total nitrogen, and mean annual precipitation, but decreased with soil pH. The variation of Nmin was ascribed predominantly to soil microbial biomass on global and biome scales. Mean annual precipitation, soil pH, and total soil nitrogen significantly influenced Nmin through soil microbes. The structural equation models (SEM) showed that soil substrates were the main factors controlling Nmin when microbial biomass was excluded. Microbe became the primary driver when it was included in SEM analysis. SEM with soil microbial biomass improved the Nmin prediction by 19% in comparison with that devoid of soil microbial biomass. The changes in Nmin contributed the most to global soil NH4+‐N variations in contrast to climate and soil properties. This study reveals the complex interactions of climate, soil properties, and microbes on Nmin and highlights the importance of soil microbial biomass in determining Nmin and nitrogen availability across the globe. The findings necessitate accurate representation of microbes in Earth system models to better predict nitrogen cycle under global change. This study provides a comprehensive evaluation of the determinants of global Nmin with a focus on soil microbial biomass. The results demonstrated that soil microbial biomass predominantly controlled the variability of Nmin at a global scale. Climate, soil properties, and substrates influenced Nmin via their impacts on soil microbial biomass. The study highlights the importance of microbial biomass in determining soil nitrogen cycling, which challenges the conventional view that climate and soil properties are the dominant drivers of soil Nmin and advances our current understanding on the global patterns of nitrogen cycle. The findings suggest that changes in soil microbial biomass under global change would result in profound consequences on ecosystem processes by changing soil Nmin. [ABSTRACT FROM AUTHOR]

A rectangular dielectric resonator antenna (DRA) with multiple polarization modes is proposed in this study. The antenna is fed by adjustable feed network composed by Wilkinson power divider and tunable phase shift elements. On this reconfigurable design, it can operate in left‐handed circular polarization, right‐handed circular polarization, and linear polarization (LP) modes. The 3‐dB axial ratio bandwidth of 30.2% for CP modes and impedance bandwidth of 33.3% for CP states are obtained. The maximum gains are 5.7 dBic and 6.34 dBi for CP and LP states. A prototype is built on the FR4 substrate with ideal switches and tested to validate the design. Simulated and measured results showed good agreement on the polarization reconfigurable performances of interest. The proposed DRA can be applied to modern wireless system with polarization diversity requirements. [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen (N) ammonification and nitrification are two primary microbial processes controlling the availability of soil ammonium (NH4+), a key nutrient for vegetative growth. The large‐scale patterns of gross ammonification (GA) and gross nitrification (GN) rates represent soil microbial adaptations to different vegetative and environmental conditions. In this study, we investigated GA and GN rates in nine forest soils along a 3,700‐km north–south transect in eastern China. We used 15N‐labelling techniques, along with field experiments and laboratory incubations, to assess in situ and potential rates of the GA and GN. The mean in situ GA rate was 4.9 ± 0.5 mg N kg−1 day−1, whereas the mean potential rate of GA was 32.0 ± 8.6 mg N kg−1 day−1. The mean in situ GN rate was 1.7 ± 0.3 mg N kg−1 day−1 (potential GN rate: 3.2 ± 0.6 mg N kg−1 day−1). GA was significantly higher than GN along the transect, and there were high variations in GA and GN among different forests. Significant relationships were identified between meteorological factors (temperature and precipitation) and the GA and GN rates during the sampling month (August 2013). However, the mean GA rate in primary forest was significantly lower in the Huzhong (HZ), Dongling (DL), Taiyue (TY) and Dinghu (DH) sites compared with other sites, whereas with the exception of the Liangshui (LS) sampling site, the mean GN rate in primary and secondary forests showed the same trends. Significant differences in GA rates were found between primary and secondary forests at the LS and Changbai (CB) sites, and differences were detected in GN rate at the HZ, LS and Jiulian (JL) sites. Structural equation modelling analysis suggested that soil N contents, microbial biomass N pool sizes and bacterial abundance are the primary determinants of the in situ rates of GA and GN. The strong control of edaphic factors on GA and GN indicates a need to improve soil N models with more explicit representation of edaphic factors and their control on soil N transformations. A plain language summary is available for this article. [ABSTRACT FROM AUTHOR]

Soil net nitrogen (N) mineralization (Nmin) is a pivotal process in the global N cycle regulating the N availability of plant growth. Understanding the spatial patterns of Nmin, its temperature sensitivity ( Q10) and regulatory mechanisms is critical for improving the management of soil nutrients. In this study, we evaluated 379 peer-reviewed scientific papers to explore how Nmin and the Q10 of Nmin varied among different ecosystems and regions at the global scale. The results showed that Nmin varied significantly among different ecosystems with a global average of 2.41 mg N soil kg−1 day−1. Furthermore, Nmin significantly decreased with increasing latitude and altitude. The Q10 varied significantly among different ecosystems with a global average of 2.21, ranging from the highest found in forest soils (2.43) and the lowest found for grassland soils (1.67) and significantly increased with increasing latitude. Path analyses indicated that Nmin was primarily affected by the content of soil organic carbon (C), soil C:N ratio, and clay content, where Q10 was primarily influenced by the soil C:N ratio and soil pH. Furthermore, the activation energy ( Ea) of soil N mineralization was significantly and negative correlated with the substrate quality index among all ecosystems, indicating the applicability of the carbon quality temperature hypothesis to soil N mineralization at a global scale. These findings provided empirical evidence supporting that soil N availability, under global warming scenarios, is expected to increase stronger in colder regions as compared with that low-latitude regions due to the higher Q10. This may alleviate the restriction of N supply for increased primary productivity at higher latitudes. [ABSTRACT FROM AUTHOR]

The frequent occurrence of cyanobacterial blooms in eutrophic lakes can lead to a high amount of biomass in aquatic systems, and following cell death, this autochthonous organic matter will eventually decompose. In this study, the effect of temperature and sediment on the chemical composition of cyanobacterial biomass residue was investigated by microcosm experiment. The results showed that the lowest cyanobacterial bloom biomass (CBB) removal efficiency was recorded at 32°C regardless of the presence or absence of sediment. Based on total organic carbon, the CBB removal efficiencies were higher than 90% at 20-29°C but less than 87.0% at 32°C. Pyrolysis gas chromatography mass spectrometry and Fourier transform infrared analysis indicated that organic nitrogen compounds ( e.g., carbamic acid monoammonium salt) and polysaccharides ( e.g., 2-propanone, 1-hydroxy-) were the main components in the residues. Based on the determined components in the residues under different conditions, unweighted pair group clustering method with arithmetic averages and principal components analysis further suggested that sediment and temperature had obvious influence on the chemical composition of CBB decomposition residues. Considering that cyanobacteria biomass is produced annually in eutrophic lakes, residues from CBB may contribute to the nitrogen/carbon cycles and macro-fauna growth in these ecosystems. [ABSTRACT FROM AUTHOR]

The carbon- and nitrogen-rich soils of montane grasslands are exposed to above-average warming and to altered precipitation patterns as a result of global change. To investigate the consequences of climatic change for soil nitrogen turnover, we translocated intact plant-soil mesocosms along an elevational gradient, resulting in an increase of the mean annual temperature by approx. 2 °C while decreasing precipitation from approx. 1500 to 1000 mm. Following three years of equilibration, we monitored the dynamics of gross nitrogen turnover and ammonia-oxidizing bacteria ( AOB) and archaea ( AOA) in soils over an entire year. Gross nitrogen turnover and gene levels of AOB and AOA showed pronounced seasonal dynamics. Both summer and winter periods equally contributed to cumulative annual N turnover. However, highest gross N turnover and abundance of ammonia oxidizers were observed in frozen soil of the climate change site, likely due to physical liberation of organic substrates and their rapid turnover in the unfrozen soil water film. This effect was not observed at the control site, where soil freezing did not occur due to a significant insulating snowpack. Climate change conditions accelerated gross nitrogen mineralization by 250% on average. Increased N mineralization significantly stimulated gross nitrification by AOB rather than by AOA. However, climate change impacts were restricted to the 2-6 cm topsoil and rarely occurred at 12-16 cm depth, where generally much lower N turnover was observed. Our study shows that significant mineralization pulses occur under changing climate, which is likely to result in soil organic matter losses with their associated negative impacts on key soil functions. We also show that N cycling processes in frozen soil can be hot moments for N turnover and thus are of paramount importance for understanding seasonal patterns, annual sum of N turnover and possible climate change feedbacks. [ABSTRACT FROM AUTHOR]

SUMMARY In order to alleviate multiple access interference and multipath interference of ultra-wideband (UWB) system, we propose the orthogonal complementary code (OCC)-based direct-sequence UWB system and offset-stacking (OS)-UWB system. OCC has perfect partial autocorrelation and cross-correlation characteristics. With the application of OCC in UWB system, we can obtain better performance in multiple access interference and multipath interference. The proposed OS-UWB structure can also achieve variable data rate transmission because of its innovative OS spreading technique. Theoretical analysis and simulation results show that the proposed UWB system can achieve excellent performance and outperform the unitary code-based direct-sequence UWB system. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Graphene is considered as a rising-star material because of its unique properties and it is a promising material for applications in many fields. In recent years, experiments on graphene fabricated by using versatile methods have shed light on the crucial problem of aggregation and restacking, which is induced by strong π-π stacking and van der Waals forces, but preparation methods for real-world applications are still a great challenge. Here we report a facile, rapid, and environmentally friendly process, the burn-quench method, that allows large-scale and controlled synthesis of ordered mesoporous nanographene with 1-5 layers, which has a high surface area and electric conductivity. Electrodes composed of nanographene with a mesoporous architecture used both in electrochemical capacitors and lithium-ion batteries have a high specific capacitance, rate capability, energy density, and cyclic stability. Our results represent an important step toward large-scale graphene synthesis based on this new burn-quench method for applications in high-performance electrochemical energy storage devices. [ABSTRACT FROM AUTHOR]

Water treatment residuals (WTRs) are effective phosphorus (P) immobilizers that have been used in constructed wetlands (CWs). In CWs, dissolved oxygen (DO) levels vary from location to location and fluctuate over time. Therefore, this work accessed the stability of P saturated ferric and alum water treatment residuals (FARs) under low (<1 mg/L), medium (2-4 mg/L), and high (5-8 mg/L) DO levels. In the experiments, which had a 40-day duration, three stages of P release from the P saturated FARs were observed: an initial rapid P desorption stage, followed by a P re-adsorption stage, and a P desorption balance stage. The strongest bonding between P and FARs occurred at the low DO level. A limited amount of Fe and Al was released from the P saturated FARs. Interestingly, the P in the FARs tended to transform from the Al bound P to the Fe bound P, and this transformation was stronger at lower DO levels. However, no more than 1.12% of the total P in the P saturated FARs was desorbed under any of these DO levels. Therefore, FARs can be considered as a safe P adsorption medium for CWs. [ABSTRACT FROM AUTHOR]