A numerical domain decomposition method for solving elliptic equations on manifolds

A new numerical domain decomposition method is proposed for solving elliptic equations on compact Riemannian manifolds. The advantage of this method is to avoid global triangulations or grids on manifolds. Our method is numerically tested on some $4$-dimensional manifolds such as the unit sphere $S^{4}$, the complex projective space $\mathbb{CP}^{2}$ and the product manifold $S^{2} \times S^{2}$.Comment: Final version. To appear in SIAM Journal on Scientific Computin

Effects of Culture on Economic Performance and Grassland Degradation

This study uses micro-level data gathered for Tibetans and Mongolians living in the same region (Qinghai Lake area in Northwest China) and having similar religion (Buddhism) and livelihoods (livestock raising) to examine how cultural differences between these two ethnic groups affect their integration into markets, their means of livestock production, and the extent of degradation of the grassland. We find significant cultural differences between the two ethnic groups, and conclude that the impact of religious attitudes on the market orientation of herder households is the dominating force explaining a relatively high degree of grassland degradation among Mongolian households

Les effets de la culture sur les performances économiques et la dégradation des prairies

Cette étude est fondée sur des informations recueillies au cours d’enquêtes sur des Tibétains et des Mongols qui vivent dans une même région (la région du lac Qinghai dans le Nord-Ouest de la Chine), pratiquent la même religion et présentent un mode de vie similaire. Il s’agira d’examiner comment les différences culturelles entre ces deux groupes ethniques affectent leur intégration au marché, leur mode d’élevage du bétail et le niveau de dégradation des pâturages. Nous constatons des différences culturelles fondamentales entre les groupes, l’impact de l’attitude religieuse sur le rapport au marché apparaissant comme la force dominante qui explique le degré relativement élevé de dégradation des prairies parmi les ménages mongols

Les effets de la culture sur les performances économiques et la dégradation des prairies

Cette étude est fondée sur des informations recueillies au cours d’enquêtes sur des Tibétains et des Mongols qui vivent dans une même région (la région du lac Qinghai dans le Nord-Ouest de la Chine), pratiquent la même religion et présentent un mode de vie similaire. Il s’agira d’examiner comment les différences culturelles entre ces deux groupes ethniques affectent leur intégration au marché, leur mode d’élevage du bétail et le niveau de dégradation des pâturages. Nous constatons des différences culturelles fondamentales entre les groupes, l’impact de l’attitude religieuse sur le rapport au marché apparaissant comme la force dominante qui explique le degré relativement élevé de dégradation des prairies parmi les ménages mongols

RIS-based IMT-2030 Testbed for MmWave Multi-stream Ultra-massive MIMO Communications

As one enabling technique of the future sixth generation (6G) network, ultra-massive multiple-input-multiple-output (MIMO) can support high-speed data transmissions and cell coverage extension. However, it is hard to realize the ultra-massive MIMO via traditional phased arrays due to unacceptable power consumption. To address this issue, reconfigurable intelligent surface-based (RIS-based) antennas are an energy-efficient enabler of the ultra-massive MIMO, since they are free of energy-hungry phase shifters. In this article, we report the performances of the RIS-enabled ultra-massive MIMO via a project called Verification of MmWave Multi-stream Transmissions Enabled by RIS-based Ultra-massive MIMO for 6G (V4M), which was proposed to promote the evolution towards IMT-2030. In the V4M project, we manufacture RIS-based antennas with 1024 one-bit elements working at 26 GHz, based on which an mmWave dual-stream ultra-massive MIMO prototype is implemented for the first time. To approach practical settings, the Tx and Rx of the prototype are implemented by one commercial new radio base station and one off-the-shelf user equipment, respectively. The measured data rate of the dual-stream prototype approaches the theoretical peak rate. Our contributions to the V4M project are also discussed by presenting technological challenges and corresponding solutions.Comment: 8 pages, 5 figures, to be published in IEEE Wireless Communication

Analysis on Fungal Diversity in Rhizosphere Soil of Continuous Cropping Potato Subjected to Different Furrow-Ridge Mulching Managements

Knowledge about fungi diversity following different planting patterns could improve our understanding of soil processes and thus help us to develop sustainable management strategies. The objective of this study was to determine the impact of different furrow-ridge mulching techniques on fungal diversity in rhizosphere soil under continuous cropping system. The investigated treatments were: flat plot without mulch (CK); flat plot with mulch (T1); on-ridge planting with full mulch (T2); on-furrow planting with full mulch (T3); on-ridge planting with half mulch (T4); and on-furrow planting with half mulch (T5). NGS (Illumina) methods and ITS1 sequences were used in monitoring fungi diversity of the potato rhizosphere soil. The fungi diversity in the rhizosphere soil was ranked in the order T5 > T2 > T4 > T1 > CK at the early growth stage and T2 > T3 > T1 > T4 > CK at the late growth stage of potato. The fungal communities found in the rhizosphere soil were Ascomycota, Zygomycota, Basidiomycota, Chytridiomycota, and other unidentified fungal communities. Among the fungal community in the rhizosphere soil, Ascomycota was found to be dominant fungi population, with the highest percentage (89%) in the T5 soil whereas the T2 soils had the lowest percentage (67%). The Fusarium abundance in fully-mulched treated soils was higher than in half-mulched treated soil. The dominant genus in the T4 soil was Mortierella, whereas lower populations (1–2%) of Scutellinia, Cryphonectria, Acremonium, and Alternaria were found in that treatment. Among the eumycetes, the dominant fungal class in all treated soils was the Sordariomycetes, which ranged from 57 to 85% in T2 and T5 soils, respectively. The Fusarium percentages in half-mulched treated soils (T4 and T5) were 55 and 28% lower than that of complete mulched treated soils (T2 and T3), respectively. The cluster analysis results showed that, CK, T4, and T5 treated soils and T1, T2, and T3 treated soils had similarities in microbial compositions, respectively. Potato tuber yield was greater under the on-ridge planting with full mulch (T2) treated soil, followed by on-ridge planting with half-mulch (T4) treated soil. The rhizosphere soil under the on-ridge planting with full-mulch (T2) soil had the highest fungal diversity, suggesting that this management was the best environment for fungi, whereas the on-ridge planting with half-mulch (T4) soil had the minimum abundance of Fusarium

Preparation and Performance of Antibacterial Polyvinyl Alcohol/Polyethylene Glycol/Chitosan Hydrogels Containing Silver Chloride Nanoparticles via One-step Method

Silver nano-particles (AgNPs)-filled antibacterial materials have been widely employed in the fields of biology and biomedicine. However, AgNPs have shown obvious cytotoxicity. Hence it is more reasonable to use silver chloride nanoparticles (AgCl NPs) to prepare antibacterial materials due to the slow release of silver ions created by AgCl NPs formed in the chitosan. In this experiment, a useful antibacterial hydrogel for skin repairation was prepared by exploring the relationship between AgCl NPs and cytotoxicity. It is worth noting that the crosslinked network structure was successfully obtained in an antibacterial AgCl/PVA (Polyvinyl alcohol)/PEG (Polyethylene glycol)/CS (Chitosan) hydrogel materials by the hydrothermal method. In detail, the dynamic particle size distribution of AgCl NPs was relatively uniform, which is analyzed by a dynamic light scattering (DLS). The internal structure of the lyophilized hydrogel showed obvious porous structure, indicating that the hydrogel had high water content. The result of X-ray photoelectron spectroscopy (XPS) confirmed the existence of a silver element. The release concentration of silver ions was analyzed by inductively coupled plasma (ICP) to study the effect of silver ions release concentration on the antibacterial activity and cytotoxicity of hydrogel. The results show that the lower concentration of silver ions can make the hydrogel have good antibacterial activity and low cytotoxicity. The bacteriostatic rate of the antibacterial hydrogel was over 90%. Simultaneously, the mechanical properties test shows that the hydrogel has good mechanical properties, which can be widely used as an antibacterial material

Religiosity and economic performance: Micro-econometric evidence from Tibetan area

We use results from a household survey to explore the relation between religiosity and our proxy for income among herders in rural Tibet. Our main results are twofold. First, there exists a positive relation between the intensity of religious beliefs (the main 'output' of the religious production process) and income -- beliefs about the afterlife affect production and savings decisions today. Second, and perhaps more surprising, we find an inverted U-shaped relation between religious 'inputs' (time and money spent in the temple) and income. While it is possible to use too much resources as religious inputs, we find that the great majority of the respondents is on the upward sloping part of the curve linking economic performance to religious inputs. We present tentative evidence that the positive impact of religiosity and income may be explained by status (reputation) and information effects associated with producing religiosity.Beliefs Religion and economics Informal institutions Social capital Buddhism

Current applications of poly(lactic acid) composites in tissue engineering and drug delivery

Biodegradable poly(lactic acid) (PLA) presents suitable physicochemical properties and biocompatibility for biomedical engineering. However, PLA has some drawbacks, such as low cell adhesion, biological inertness, low degradation rate, and acid degradation by-products. In this review, recent progress on strategies to address these problems is summarized, including novel fabrication techniques, high-performance PLA composites, and their applications for tissue engineering and drug delivery. The scaffolds, especially for bone regeneration, blood vessels, organs, and skin regeneration are evaluated, in terms of in vivo and in vitro biocompatibility and biodegradability. The enhanced mechanical, thermal, and rheological properties of PLA biocomposites are analyzed in detail. PLA biocomposites for drug encapsulation, sustained release, and tumor-targeting are also reviewed. Furthermore, the challenges and future perspectives on PLA-based biocomposites are discussed

P, N-decorated halloysite nanotubes for flame retardancy enhancement of polyamide 6/aluminum diethylphosphinate

Flame-retardant functionalized nanomaterials have attracted much research interests due to the combined advantages of organic and inorganic components. In the present study, P, N-decorated halloysite nanotube (MA-PPA@HNT) was prepared via simple steps of phenphosphinic acid intercalation and subsequent electrostatic interaction with melamine. Compared to unmodified HNT, the incorporation of MA-PPA@HNT into polyamide 6 (PA6)/aluminum diethylphosphinic acid (AlPi) composite results in significant improvement of flame retardancy. At equal HNT loading of 2wt%, the UL-94 rating grade of PA6/AlPi/MA-PPA@HNT composite was V-0, whereas that of PA6/AlPi/HNT composite V-2. And compared with PA6, there is a decrease of peak heat release rate (pHRR) and total heat release (THR) by 72.6% and 17.4%, respectively. The flame retardant mechanism was analyzed by cone calorimetry, gas volatility and characterization of char residues. It is considered that MA-PPA@HNT plays the critical role of promoting the formation of P, Si-rich intumescent char in the condensed phase and enhancing the barrier effect for heat and mass transfer