bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil respiration sensitivities to water and temperature in a revegetated desert
Authors: Zhang Zhi‐Shan , Dong Xue‐Jun , Xu Bing‐Xin , Chen Yong‐Le , Zhao Yang , Gao Yan‐Hong , Hu Yi‐Gang , Huang Lei 
Published: March 2015

AbstractSoil respiration in water‐limited ecosystems is affected intricately by soil water content (SWC), temperature, and soil properties. Eight sites on sand‐fixed dunes that revegetated in different years since 1950s, with several topographical positions and various biological soil crusts (BSCs) and soil properties, were selected, as well as a moving sand dune (MSD) and a reference steppe in the Tengger Desert of China. Intact soil samples of 20 cm in depth were taken and incubated randomly at 12 levels of SWC (0 to 0.4 m3 m−3) and at 9 levels of temperature (5 to 45°C) in a growth chamber; additionally, cryptogamic and microbial respirations (RM) were measured. Total soil respiration (RT, including cryptogamic, microbial, and root respiration) was measured for 2 years at the MSD and five sites of sand‐fixed dunes. The relationship between RM and SWC under the optimal SWC condition (0.25 m3 m−3) is linear, as is the entire range of RT and SWC. The slope of linear function describes sensitivity of soil respiration to water (SRW) and reflects to soil water availability, which is related significantly to soil physical properties, BSCs, and soil chemical properties, in decreasing importance. Inversely, Q10 for RM is related significantly to abovementioned factors in increasing importance. However, Q10 for RT and respiration rate at 20°C are related significantly to soil texture and depth of BSCs and subsoil only. In conclusion, through affecting SRW, soil physical properties produce significant influences on soil respiration, especially for RT. This indicates that a definition of the biophysical meaning of SRW is necessary, considering the water‐limited and coarse‐textured soil in most desert ecosystems.
Isotopic evidence for the turnover of biological reactive nitrogen in the Pearl River Estuary, south China
Authors: Ye Feng , Ni Zhixin , Xie Luhua , Wei Gangjian , Jia Guodong 
Published: March 2015

AbstractNitrate (NO3−) concentrations and the isotopic composition (δ15N and δ18O) of water samples from the Pearl River Estuary (PRE), south China, were measured to constrain N sources and processing in springtime. Nitrate concentrations decreased at higher salinities, and dual isotopic values were correlated with 1/[NO3−], both of which suggest mixing of eutrophic freshwater and oligotrophic seawater. However, δ15N and δ18O values did not closely follow the expected mixing lines. At low salinities (0–3.0), some samples exhibited high δ15N and low δ18O values compared with those of the riverine end‐member, indicating that sewage is a significant source of nitrate (up to 19.0% calculated from δ15N). At salinities of >3.0, Δδ15N and Δδ18O values are linearly correlated with lnƒ (the fraction of NO3− remaining in the system), which is attributable to isotopic Rayleigh fractionation during phytoplankton uptake of nitrate. However, the linear relationship between Δδ15N and Δδ18O is different between the west and east PRE, with a slope of 1.18 in the west and 1.59 in the east. This difference most likely resulted from varying degrees of nitrification due to different water velocities and residence times in the two areas. Our data therefore indicate that dual nitrate isotopic signatures are a valuable way to constrain the sources and behavior of nitrate in river‐dominated estuaries.
Influences of the day‐night differences of ionospheric variability on the estimation of GPS differential code bias
Authors: Li L. X. , Zhang D. H. , Zhang S. R. , Coster A. J. , Hao Y. Q. , Xiao Z. 
Published: March 2015

AbstractThe estimation of differential code bias (DCB) of GPS system is one of the necessary steps for total electron content (TEC) derivation from GPS measurements. Usually, the method for estimating the GPS DCBs follows the assumption of the gentle temporal and spatial variation of the ionosphere, but this assumption is just an approximation because of the ionosphere's inherent variability. It has been indicated that the estimated GPS satellite DCBs are sometimes influenced by the ionospheric conditions. In this paper, we demonstrate a possible influence of ionospheric variability that differs between day and night on the estimated DCBs from measurements of a single GPS station. It is found that the average standard deviations (STDs) of the satellite DCBs estimated with daytime data are higher than that with the nighttime data. To reduce this day‐night difference effect on GPS DCB determination, we use an improved estimation method based on the primary features of the ionospheric variability with local time. A local time dependent weighting function was introduced into the original least squares DCBs estimation algorithm. A test with data for BJFS station (39.60°N, 115.89°E) in 2001 indicates that the STD of the DCBs decreases from 2.533 TECU (total electron content unit, 1 TECU = 1016 el m−2) to 2.308 TECU, or by 8.9%, after the improved method was applied. For comparison, another test for the same station in 2009 indicates that the STD decreases from 1.344 TECU to 1.295 TECU. The amplitude of the 2009 improvement is very limited, only about 3.6%. The difference of the percentage improvements can probably be attributed to the different ionospheric conditions between 2001 and 2009.
Impact of cross‐polarization isolation on polarimetric target decomposition and target detection
Authors: Xu Feng , Wang Haipeng , Jin Ya‐Qiu , Liu Xiuqing , Wang Robert , Deng Yunkai 
Published: March 2015

AbstractCross‐polarization isolation is one of the key engineering parameters for a polarimetric radar system. Previous studies focused more on the calibration of cross‐talk contamination. This paper presents a numerical evaluation of the requirement for cross‐polarization isolation from the data users' perspective, i.e., the quantitative impact of polarization cross talk on polarimetric target decomposition and the associated applications such as classification and detection. Sensitivity analyses of several commonly used target decomposition parameters suggest that a theoretical lower bound of −32 dB isolation level is preferred to avoid any significant impact on these parameters. Our analyses with both simulated and real synthetic aperture radar (SAR) data show that a level of −25 dB would be acceptable for general terrain surface classification. This requirement is also true for man‐made target detection application. Using simulated SAR images of man‐made targets in natural environment, sensitivity analyses on two polarimetric detectors, Yang and Marino, both suggest that target detection performance would break down rapidly if isolation deteriorates from −25 dB to −20 dB.
Adsorptive uptake of water by semisolid secondary organic aerosols
Authors: Pajunoja Aki , Lambe Andrew T. , Hakala Jani , Rastak Narges , Cummings Molly J. , Brogan James F. , Hao Liqing , Paramonov Mikhail , Hong Juan , Prisle Nønne L. , Malila Jussi , Romakkaniemi Sami , Lehtinen Kari E. J. , Laaksonen Ari , Kulmala Markku , Massoli Paola , Onasch Timothy B. , Donahue Neil M. , Riipinen Ilona , Davidovits Paul , Worsnop Douglas R. , Petäjä Tuukka , Virtanen Annele 
Published: March 2015

AbstractAerosol climate effects are intimately tied to interactions with water. Here we combine hygroscopicity measurements with direct observations about the phase of secondary organic aerosol (SOA) particles to show that water uptake by slightly oxygenated SOA is an adsorption‐dominated process under subsaturated conditions, where low solubility inhibits water uptake until the humidity is high enough for dissolution to occur. This reconciles reported discrepancies in previous hygroscopicity closure studies. We demonstrate that the difference in SOA hygroscopic behavior in subsaturated and supersaturated conditions can lead to an effect up to about 30% in the direct aerosol forcing—highlighting the need to implement correct descriptions of these processes in atmospheric models. Obtaining closure across the water saturation point is therefore a critical issue for accurate climate modeling.
Comparison of the mass circulation and AO indices as indicators of cold air outbreaks in northern winter
Authors: Yu Yueyue , Ren Rongcai , Cai Ming 
Published: March 2015

AbstractUsing the daily ERA‐Interim reanalysis data set for the 32 winters in 1979–2011, we find that midlatitude cold air outbreaks (CAOs) tend to preferentially occur within a week after simultaneously stronger mass circulations into the Arctic region in upper levels and out of the Arctic region below. The relationship of CAOs with Arctic Oscillation (AO) is less robust because temporal changes of AO are resulted from a small imbalance between the poleward and equatorward branches of the mass circulation. Results indicate that only when the poleward branch leads the equatorward branch (44% of all cases), CAOs tend to take place within a week after a negative phase of AO, whereas when the equatorward branch leads (19%), CAOs tend to occur after a positive phase of AO. In the remaining cases when the two branches are almost in phase, CAOs can be observed during either negative (24%) or positive (13%) phase of AO.
Paleomagnetic tests of tectonic reconstructions of the India‐Asia collision zone
Authors: Huang Wentao , van Hinsbergen Douwe J. J. , Lippert Peter C. , Guo Zhaojie , Dupont‐Nivet Guillaume 
Published: March 2015

AbstractSeveral solutions have been proposed to explain the long‐standing kinematic observation that postcollisional upper crustal shortening within the Himalaya and Asia is much less than the magnitude of India‐Asia convergence. Here we implement these hypotheses in global plate reconstructions and test paleolatitudes predicted by the global apparent polar wander path against independent, and the most robust paleomagnetic data. Our tests demonstrate that (1) reconstructed 600–750 km postcollisional intra‐Asian shortening is a minimum value; (2) a 52 Ma collision age is only consistent with paleomagnetic data if intra‐Asian shortening was ~900 km; a ~56–58 Ma collision age requires greater intra‐Asian shortening; (3) collision ages of 34 or 65 Ma incorrectly predict Late Cretaceous and Paleogene paleolatitudes of the Tibetan Himalaya (TH); and (4) Cretaceous counterclockwise rotation of India cannot explain the paleolatitudinal divergence between the TH and India. All hypotheses, regardless of collision age, require major Cretaceous extension within Greater India.
Turbulent mixing and its impact on lower tropospheric moisture over tropical ocean
Authors: Bellenger Hugo , Katsumata Masaki , Yoneyama Kunio 
Published: March 2015

AbstractThe variability of lower tropospheric humidity is a crucial feature of the tropical climate. Among the processes that impact moisture budget, the vertical transport by turbulent mixing is generally overlooked. Using observations from Cooperative Indian Ocean experiment on intraseasonal variability/Dynamics of the Madden‐Julian Oscillation (MJO), CINDY/DYNAMO, campaign, this is a first attempt to quantify it over the tropical ocean. Turbulent patches of ~100 m depth are observed in relation with large vertical gradients of specific humidity. Intense mixing is diagnosed within these intermittent patches. Three approaches are used to diagnose the overall effect of this intermittent turbulence. Large uncertainties on the corresponding eddy diffusivity coefficient arise from parameters hard to experimentally constrain. However, dry conditions are associated with steep moisture vertical gradients above the boundary layers. Owing to the uncertainties on the eddy diffusivity, these gradients can correspond to negligible or to significant moisture tendencies (~0.5–1 g kg−1 d−1) during the recovery following a dry intrusion or the preconditioning stage of an MJO.
Gold‐Catalyzed and Gold‐Mediated Synthesis of Heterocycles
Authors: Vilhelmsen Mie HØjer , Hashmi A. Stephen K. 
Published: March 2015

Abstract
This chapter will review the vast synthetic methods available in homogeneous gold catalysis towards the preparation of heterocycles. Particularly, reactions in which the gold catalyst activates a carbon‐carbon multiple bond have received attention over the past three decades, but also rearrangements, cycloadditions, coupling reactions, and oxidative cyclizations have found use in the field. Each of these methodologies will be discussed through reactions in which the gold catalyst plays a central role in the cyclization by a carbon‐heteroatom bond formation. Reactions in which the heterocycles are formed by a gold catalyzed carbon‐carbon bond formation will not be included here. Finally, the general reaction mechanisms of the catalysis will be given and where appropriate specific reaction pathways will be reviewed.
Gold‐Catalyzed Reactions of Cyclopropenes
Authors: Archambeau Alexis , Miege Frederic , Cossy Janine , Meyer Christophe 
Published: March 2015

Abstract
Cyclopropenes have often been used as substrates in transition metal‐promoted or catalyzed reactions. Since the first reports in 2008, gold‐catalyzed reactions of cyclopropenes have rapidly evolved to an active research field. The observed reactivity is essentially related to the ability of cyclopropenes to undergo ring‐opening in the presence of gold(I) complexes and hence generate alkenyl gold carbenoids. These latter organogold species act as key reactive catalytic entities in a wide range of transformations including inter‐ or intramolecular nucleophilic additions of heteroatom or carbon nucleophiles, carbene‐type coupling reactions and olefin cyclopropanations. Additionally, cyclopropenes can also behave as π nucleophiles in gold‐catalyzed enyne cycloisomerizations wherein alkynes are preferentially activated by gold(I) complexes. A wide variety of acyclic and cyclic products can be produced by these gold‐catalyzed reactions of cyclopropenes and the different contributions as well as the theoretical studies in this field have been summarized in this chapter.
The Chemistry of Gold–Metal Bonds
Authors: Silvestru Cristian , Laguna Antonio 
Published: March 2015

AbstractThis chapter summarizes the preparation, structural characterization and properties of heterometallic gold compounds built through metal–metal interactions or bonds. They are mainly synthesized following four different strategies. Two of them use the acid‐base process with gold precursors acting as acids or organoaurates acting as bases, the third one consists of the use of bidentate bridging ligands, and the fourth uses the isolobal relationship between the [(R3P)Au]+cations and the proton in carbonyl clusters. The structural behavior of these complexes has been studied by different methods, mainly Mössbauer spectroscopy, nuclear magnetic resonance spectroscopy, and single‐crystal X‐ray diffraction. Their structures show discrete molecules, extended linear chains or even two‐ or three‐dimensional networks. Many of these complexes display luminescence and the emissions are strongly dependent on their structures. Some theoretical calculations are able to show that the formation of metal–metal interactions or bonds, as well as the gold environments, are the main aspects that affect the energy of the emissions. Other very promising areas of research such as the potential applications in electrochemistry, in biology (antiproliferative and antitumoral activity) or as homogeneous and heterogeneous catalysts are also discussed.
Nasal lavage levels of granulocyte‐macrophage colony‐stimulating factor and chronic nasal hypereosinophilia
Authors: De Corso Eugenio , Baroni Silvia , Lucidi Daniela , Battista Mariapina , Romanello Matteo , Autilio Chiara , Morelli Renato , Di Nardo Walter , Passali Giulio Cesare , Sergi Bruno , Bussu Francesco , Fetoni Anna Rita , Zuppi Cecilia , Paludetti Gaetano 
Published: March 2015

BackgroundThe aim of the present study was to measure levels of granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) in nasal lavage of patients affected by chronic eosinophilic sinonasal inflammation to clarify the relationship with eosinophilic tissue infiltration and clinical features.MethodsBetween November 2012 and June 2013, we selected 70 patients with chronic eosinophilic inflammation (average age 41.8 years) who were classified into the following groups: persistent allergic rhinitis (group 1), noninfectious non‐allergic rhinitis with eosinophilia syndrome (group 2) and chronic rhinosinusitis with polyps (group 3). Finally, we enrolled 20 healthy subjects as controls (group 4). All patients underwent symptoms score questionnaire based on a visual analogue scale, nasal endoscopy and/or computed tomography (CT) scan, and allergy testing. Nasal cytology by scraping of the mucosa and GM‐CSF assays in nasal lavage were performed in all subjects.ResultsDetectable levels of GM‐CSF were found in 34 of 70 (48.57%) patients, with an average concentration of 2.67 ± 0.8 pg/mL, whereas in controls only 1 of 20 individuals showed detectable GM‐CSF levels. Eosinophil infiltration was significantly higher in patients with detectable GM‐CSF compared to those with undetectable levels (49.4% vs 39.2%, respectively; p < 0.05). Furthermore, significant weakly‐moderate correlation was found between GM‐CSF levels and percentage of eosinophil infiltration in tissue (p < 0.05). Correlation between symptom scores and GM‐CSF levels was significant only in group 2, which showed higher average concentrations of GM‐CSF compared to groups 1 and 3 (2.9 pg/mL vs 1.6 pg/mL and 1.8 pg/mL, respectively; p < 0.05).ConclusionOur data confirm that GM‐CSF is more frequently detectable in nasal lavages of patients affected by chronic sinonasal eosinophilic inflammation than in controls. Statistical analyses revealed a significant weakly‐moderate correlation between GM‐CSF levels in nasal lavage of all patients and percentage of eosinophil infiltration of nasal mucosa.
Simultaneous Capture, Detection, and Inactivation of Bacteria as Enabled by a Surface‐Enhanced Raman Scattering Multifunctional Chip
Authors: Wang Houyu , Zhou Yanfeng , Jiang Xiangxu , Sun Bin , Zhu Ying , Wang Hui , Su Yuanyuan , He Yao 
Published: March 2015

AbstractHerein, we present a multifunctional chip based on surface‐enhanced Raman scattering (SERS) that effectively captures, discriminates, and inactivates pathogenic bacteria. The developed SERS chip is made of a silicon wafer decorated with silver nanoparticles and modified with 4‐mercaptophenylboronic acid (4‐MPBA). It was prepared in a straightforward manner by chemical reduction assisted by hydrogen fluoride etching, followed by the conjugation of 4‐MPBA through AgS bonds. The dominant merits of the fabricated SERS chip include excellent reproducibility with a relative standard deviation (RSD) value smaller than 11.0 %, adaptable bacterial‐capture efficiency (ca. 60 %) at low concentrations (500–2000 CFU mL−1), a low detection limit (down to a concentration of 1.0×102 cells mL−1), and high antibacterial activity (an antibacterial rate of ca. 97 %). The SERS chip enabled sensitive and specific discrimination of Escherichia coli and Staphylococcus aureus from human blood.
Adsorption behavior of herbicide paraquat from aqueous solutions using starfish particles: kinetic, isotherm, and thermodynamic studies
Authors: Hao Han , Feng Jianguo , Chen Weitao , Xiang Sheng , Liu Wenjun , Wu Xuemin 
Published: March 2015

AbstractThe adsorption of paraquat (PQ) on starfish particles was investigated to calculate the kinetic, isotherm, and thermodynamic parameters. The experiments were carried out as a function of particle size of adsorbent, adsorbent dosage, contact time, initial PQ concentration, stirring speed, and temperature. The kinetic data followed the pseudo‐second‐order kinetic model, and the equilibrium data were well fitted by the Langmuir isotherm model with the maximum adsorption amount of 10.235 mg g−1 at 288 K. Thermodynamic parameters, including standard Gibbs free energy changes (ΔG0), standard entropy changes (ΔS0), and standard enthalpy changes (ΔH0) were also calculated. The results demonstrated that PQ was adsorbed onto starfish particles spontaneously and exothermically in nature. The adsorption process followed a physisorption mechanism. In addition, the starfish particles were successfully utilized to real sample. Hence, starfish particles are eligible for treating the wastewater containing PQ as an effective and low‐cost adsorbent. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.
Diffuse color patterning using blended electrochromic polymers for proof‐of‐concept adaptive camouflage plaques
Authors: Brooke Robert , Fabretto Manrico , Pering Samuel , Switalska Eliza , Reeks Lachlan , Evans Drew , Murphy Peter 
Published: March 2015

ABSTRACTA study using three different pairs of electrochromic polymers (ECPs) synthesized onto plaques by means of a modified vapor phase polymerization (VPP) technique is presented. Restriction of the respective polymerization times, allowed both faster and slower polymerizing monomers to be controlled, and produced blended plaques with visually diffuse interfaces. The ECPs within the blended plaques retain their individual electrochromic behavior and when encapsulated into an electrochromic device, show outstanding optical switching performance with little degradation evident over 10,000 cycles, coupled with a switching time of the order of 1 second. Blends also allow multiple diffuse color changes within an electrochromic device, due to the difference in oxidation potentials of the individual ECPs, making them candidates for adaptive camouflage use. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42158.
Straight‐Line Tracking Control of an Agricultural Vehicle with Finite‐Time Control Technique
Authors: Jiang Yuexia , Ding Shihong , Zhao Dean , Ji Wei 
Published: March 2015

AbstractFor the agricultural vehicle straight‐line tracking system, three control algorithms based upon the finite‐time control technique have been proposed to force the vehicle to track a straight line. Without considering the lumped disturbance, a backstepping‐like finite‐time state‐feedback controller is first developed. On this basis, an adaptive state‐feedback controller in conjunction with integral sliding mode is further developed in the presence of the lumped disturbance. Finally, a sliding mode disturbance observer is given to estimate the lumped disturbance, and the composite control scheme is presented. Under the composite controller, the lumped disturbance can be compensated and thus the disturbance rejection property has been significantly improved. Simulation results verify the proposed control algorithms.
Application Of H2/H∞ Technique To Aircraft Landing Control
Authors: Lungu Mihai , Lungu Romulus 
Published: March 2015

AbstractThe paper describes the automatic control of an aircraft in the longitudinal plane during landing, taking into account sensor errors and disturbances. Aircraft auto‐landing is achieved by combining H2 and H∞ control techniques, thereby obtaining a robust H2/H∞ controller. It provides good precision tracking and robust stability with respect to the uncertainties caused by different disturbances and noise‐type signals. The weights of the H2 and H∞ control techniques within the robust H2/H∞ controller are adjusted so that the aircraft accurately tracks the desired trajectory during the two main stages of the landing process. The theoretical results are validated by numerical simulations for the landing of a Boeing; the results are very good (Federal Aviation Administration accuracy requirements for Category III are met) and prove the robustness of the new auto‐landing system even in the presence of disturbances and sensor errors.