Description: SUMMARY Stress wave attenuation across fractured rock masses is a great concern of underground structure safety. This paper presents an analytical study on wave attenuation across parallel fractures at arbitrary incidence angles, where multiple reflections occurring between fractures are taken into account. Combined with displacement discontinuous model, plane wave analysis and propagator matrix method are applied to develop relations between the first layer and the n th layer with respect to potential amplitudes or displacements and stresses in matrix form. With initial and boundary conditions for different scenarios, potential amplitudes in any layer or displacements and stresses at any point can be obtained by solving corresponding matrixes. After parametric studies, it is found that parameters including incidence angle, normalized fracture stiffness, number of fractures, and fracture spacing have obvious effects on wave attenuation across parallel fractures. Copyright © 2011 John Wiley & Sons, Ltd.

Description: SUMMARY In this paper, the numerical manifold method (NMM) is extended to study wave propagation across rock masses. First, improvements to the system equations, contact treatment, and boundary conditions of the NMM are performed, where new system equations are derived based on the Newmark assumption of the space–time relationship, the edge-to-edge contact treatment is further developed for the NMM to handle stress wave propagation across discontinuities, and the viscous non-reflection boundary condition is derived based on the energy minimisation principle. After the modification, numerical comparisons between the original and improved NMM are presented. The results show that the original system equations result in artificial numerical damping, which can be overcome by the Newmark system equations. Meanwhile, the original contact scheme suffers some calculation problems when modelling stress wave propagation across a discontinuity, which can be solved by the proposed edge-to-edge contact scheme. Subsequently, the influence of the mesh size and time step on the improved NMM for stress wave propagation is studied. Finally, 2D wave propagation is modelled, and the model's results are in good agreement with the analytical solution. Copyright © 2013 John Wiley & Sons, Ltd.

Description: ABSTRACT Knowledge of the effects of land use on soil moisture variations is necessary to improve land and agricultural water management in the semi-arid Chinese Loess Plateau. However, previous studies are insufficient to guide management practice in this area and improvement is needed to help with the development of the ‘Grain for Green’ programme. As part of the ‘Grain for Green’ programme, we examined the effects of five land uses (fallow, grassland, cropland, 3-year and 8-year jujube orchards) on soil water variations in a small catchment on the Loess Plateau. Soil moisture at 0–160 cm depth was monitored approximately weekly at 47 sites from 17 August to 19 October 2009 and from 4 April to 27 September 2010 using a portable time domain reflectometer. Results indicated that mean soil water profiles in different land uses varied with time, land use induced spatial variations of soil water but exerted negligible influence on soil water temporal patterns, and soil water content was of the greatest spatial variability with moderate means (approximately 20 per cent). Furthermore, the relationship between standard deviation and mean water content was dependent on soil depth, although it was negligibly affected by land use. Profile soil water for five land uses was different in various seasons, precipitation infiltration depth exhibited a positive correlation with precipitation, and the whole profile soil moisture (0–160 cm) was complemented following a 93·5-mm rainfall event. The findings presented here provide helpful information for land and agricultural water management in this area. Copyright © 2011 John Wiley & Sons, Ltd.

Description: ABSTRACT Knowledge of the effects of land use on soil moisture variations is necessary to improve land and agricultural water management in the semi-arid Chinese Loess Plateau. However, previous studies are insufficient to guide management practice in this area and improvement is needed to help with the development of the ‘Grain for Green’ programme. As part of the ‘Grain for Green’ programme, we examined the effects of five land uses (fallow, grassland, cropland, 3-year and 8-year jujube orchards) on soil water variations in a small catchment on the Loess Plateau. Soil moisture at 0–160 cm depth was monitored approximately weekly at 47 sites from 17 August to 19 October 2009 and from 4 April to 27 September 2010 using a portable time domain reflectometer. Results indicated that mean soil water profiles in different land uses varied with time, land use induced spatial variations of soil water but exerted negligible influence on soil water temporal patterns, and soil water content was of the greatest spatial variability with moderate means (approximately 20 per cent). Furthermore, the relationship between standard deviation and mean water content was dependent on soil depth, although it was negligibly affected by land use. Profile soil water for five land uses was different in various seasons, precipitation infiltration depth exhibited a positive correlation with precipitation, and the whole profile soil moisture (0–160 cm) was complemented following a 93·5-mm rainfall event. The findings presented here provide helpful information for land and agricultural water management in this area. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Background Pemphigus is an organ-specific autoimmune bullous disease, in which the pathogenic mechanism is complicated and not fully understood. B cells have multiple functions. Besides the positive regulation, they also play negative regulatory roles in the immune response. Currently, the critical roles of Bregs have been revealed in some autoimmune diseases. Objectives To determine the role of Bregs in pemphigus, we examined the frequency and regulatory function of CD19 + CD24 hi CD38 hi Bregs in the patients with pemphigus. Methods The frequencies of CD19 + CD24 hi CD38 hi Bregs were detected from 34 pemphigus patients and 20 healthy controls, and IL-10 secretion was processed after stimulating B cells at different time points. The specific anti-Dsg antibody titers and their subclasses were also measured. Furthermore, we analyzed the antibody response and cytokine production from PBMCs with or without Bregs in both groups. Results The number of Bregs was increased significantly in pemphigus patients than that in healthy controls (14.7±7.1% vs 9.4±2.8%, p〈0.001), and the proportion of Bregs in the active groups (newly diagnosed and chronic active patients) was significantly higher than that in remittent individuals (16.0±6.6% vs 13.4±7.5%, p=0.035). The IL-10-producing B cells were significantly increased upon stimulation both in patients and in healthy controls. However, the increasing folding number of IL-10-producing B cells between short term and long term stimulation was significantly lower in pemphigus patients (1.0 fold vs 2.6 fold increasing in control group, p=0.001). Strikingly, Bregs from the controls were able to suppress IFN-γ expression, Th1 immune response (the inhibition rate: 38.1%), while the suppressive function of Bregs from the patients was significantly decreased (the inhibition rate: 11.9%). There was no difference in antibody levels from PBMCs with or without Bregs after stimulation. Conclusions Our results suggest that Bregs in pemphigus patients are elevated in the periphery but with defective regulatory function on Th1 cells. This article is protected by copyright. All rights reserved.

Description: We conducted a pot experiment using a wheat-millet rotation to examine the effects of two successive rice-straw biochar applications on crop growth and soil properties in acidic oxisols and alkaline cambosols from China. Biochar was incorporated into soil at rates of 0, 2.25 or 22.5 Mg/ha at the beginning of each crop season with identical applications of NPK fertilizer. In the oxisols, the largest biochar treatment enhanced soil pH and cation exchange capacity, decreased soil bulk density, improved soil P, K, Ca and Mg availability and enhanced their uptake, and increased wheat and millet yields by 157 and 150% for wheat grain and straw, respectively, and 72.6% for millet straw. In the cambosols, biochar treatment decreased soil bulk density, improved P and K availability, increased N, P and K uptake by crops and increased wheat and millet straw yields by 19.6 and 60.6%, respectively. Total soil organic carbon increased in response to successive biochar applications over the rotation. No difference in water-soluble organic carbon was recorded between biochar-treated and control soils. Converting straw to biochar and treating soils with successive applications may be a viable option for improving soil quality, sequestering carbon and utilizing straw resources in China.

Description: About 8-year electron density profile (EDP) data from the COSMIC/FORMOSAT-3 satellites radio occultation technique were used to investigate the additional stratification of the F2 (the so-called F3 layer) layer over the equatorial and low-latitude ionosphere on a global scale for both the bottomside and topside ionosphere. The F3 layer was recognized through the altitude differential profile featured by two maxima existing from the selected EDP profile. There were ~37, 000 (bottomside) and 25, 000 (topside) cases of F3 layer selected out of ~1.27 million occultation events at equatorial and low-latitude areas during the period of April 2006-August 2014. The statistical results for the bottomside ionosphere resemble that reported in Zhao et al . [2011a], while in the topside the highest occurrence of F3 layer shows a 3-4 hours delay depending on the altitude range of the stratification. The magnetic latitude distribution shows different dependence with a tendency to form a single crest toward high altitude. Also the seasonal variation is weaker in the topside ionosphere compared to the bottomside one, especially in the high altitude. Then we build up an empirical model of the F3 layer occurrence using the bottomside statistics based on empirical orthogonal function (EOF) decomposition as it gets the inherent characters inside the data set and converges quickly. The model well grasps the main features of the F3 occurrence e.g., the F3 occurrence's sensitivity on the magnetic latitude. Further, in order to accommodate the ground observation a corrected factor was introduced. As F3 layer is an important phenomenon in the low latitude ionosphere, we have made an attempt to describe its feature with a consecutive function although future work needs to be done for an overall expression of this structure.

Description: Proterozoic mafic dykes from the southwestern Vestfold Block experienced heterogeneous granulite facie metamorphism, characterized by spotted or fractured garnet-bearing aggregates in garnet-absent groundmass. The garnet-absent groundmass typically preserves an ophitic texture composed of lathy plagioclase, intergranular clinopyroxene and Fe–Ti oxides. Garnet-bearing domains consist mainly of a metamorphic assemblage of garnet, clinopyroxene, orthopyroxene, hornblende, biotite, plagioclase, K-feldspar, quartz and Fe–Ti oxides. Chemical compositions and textural relationships suggest that these metamorphic minerals reached local equilibrium in the centre of the garnet-bearing domains. Pseudosection calculations in the model system NCFMASHTO (Na 2 O–CaO–FeO–MgO–Al 2 O 3 –SiO 2 –H 2 O–TiO 2 –Fe 2 O 3 ) yield P – T estimates of 820–870 °C and 8.4–9.7 kbar. Ion microprobe U–Pb zircon dating reveals that the NW- and N-trending mafic dykes were emplaced at 1764 ± 25 and 1232 ± 12 Ma, respectively, whereas their metamorphic ages cluster between 957 ± 7 and 938 ± 9 Ma. The identification of granulite facies mineral inclusions in metamorphic zircon domains is also consistent with early Neoproterozoic metamorphism. Therefore, the southwestern margin of the Vestfold Block is inferred to have been buried to depths of ~ 30–35 km beneath the Rayner orogen during the late stage of the late Mesoproterozoic/early Neoproterozoic collision between the Indian craton and east Antarctica (i.e. the Lambert Terrane or the Ruker craton including the Lambert Terrane). The lack of penetrative deformation and intensive fluid–rock interaction in the rigid Vestfold Block prevented the nucleation and growth of garnet and resulted in the heterogeneous granulite facies metamorphism of the mafic dykes. This article is protected by copyright. All rights reserved.

Description: Horizontal transfer of catabolic genes for pollutant degradation among rhizobacteria plays an important role in environmental bioremediation, but lacks support from field trial data. To address this problem, Pseudomonas fluorescens strain TP13 was inoculated into the soils of a phenol-contaminated farmland on which tomato seedlings were growing in April 2009, 2010, 2011 and 2012. Results consistently showed that introduction of TP13 strain significantly reduced phenol content and increased plant biomass after 20 days, compared with controls. Strain TP13 was able to colonize the plant rhizosphere and the number of rhizosphere bacteria which were grown on phenol and contained the plasmids containing the gene encoding for catechol 2, 3-dioxygenase (C23O) increased gradually in the later stages of the experiment. The increase in magnitude of the plasmid-containing rhizosphere bacteria correlated well with plant biomass, while the number of plasmid-containing rhizosphere bacteria and phenol content was strongly negatively correlated. Furthermore, six strains (T1-T6) of rhizosphere bacteria were isolated and found to possess large plasmids containing identical C23O genes and similar Hind III restriction patterns. Sequence alignment showed that the C23O genes from strains T1-T6 contained almost identical sequences and the sequence of the C23O of strain T1 was the same as that of strain TP13. These data indicated that the plasmids were transferred from strain TP13 to these rhizosphere bacteria and that horizontal gene transfer stimulated phenol degradation and plant growth in the contaminated farmland. This is an important finding for in situ remediation of contaminated farmland.

Description: SUMMARY Particle manifold method (PMM) is a new extension of the numerical manifold method (NMM). PMM uses a mathematical cover system to describe the motion and deformation of a particle-based physical domain. By introducing the concept of particle into NMM, PMM takes the advantages of easy topological and contact operations with particles. In this article, the methodology, formulations and implementation of the method are presented, together with modelling examples for validation. It is found that good solutions for both continuous and discontinuous problems are obtained by the new developed PMM. Due to the underlying coupled continuum-discontinuum property of PMM, it has great potential for modelling of geomechanical problems. Copyright © 2012 John Wiley & Sons, Ltd.