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bstract
Using the Cachazo-He-Yuan (CHY) formalism, we prove a recursive expansion of tree level single trace Einstein-Yang-Mills (EYM) amplitudes with an arbitrary number of gluons and gravitons, ...which is valid for general spacetime dimensions and any helicity configurations. The recursion is written in terms of fewer-graviton EYM amplitudes and pure Yang-Mills (YM) amplitudes, which can be further carried out until we reach an expansion in terms of pure YM amplitudes in Kleiss-Kuijf (KK) basis. Our expansion then generates naturally a spanning tree structure rooted on gluons whose vertices are gravitons. We further propose a set of graph theoretical rules based on spanning trees that evaluate directly the pure YM expansion coefficients.
Traditional rural residential household heating in winter in northern China has caused great burden to green development due to overdependence on scattered coal and other non-renewable energies that ...are major contributors of environmental pollution. Clean heating policy has been constantly altering this situation ever since its implementation in 2017, but there are some worries about the overdependence on fiscal subsidy to complete the transformation. The present study was based on a survey carried out in 2018 in one of the pilot cities for the policy in order to explore whether perceptual factors instead of actual subsidy shape public acceptance of clean heating indicated by satisfaction and willingness to pay (WTP). The results revealed that perceived fiscal subsidy turns out to be the only perceptual factor that has positive significant association with satisfaction when controlling for household annual income and education, and that adoption of electric heating causes more satisfaction compared with other types of clean heating. Meanwhile, perceived fiscal subsidy is also positively associated with WTP. Based on our findings, we provide insights at the group and the individual level for the governments to better adjust and conduct clean heating policy as well as future sustainable programs in rural areas.
•Rural residents in one pilot city of clean heating policy were surveyed.•Residents generally evaluated the performance of clean heating positively.•Higher perceived fiscal subsidy improves satisfaction with clean heating.•Overall willingness to pay for clean heating is low.•Higher perceived fiscal subsidy improves willingness to pay for clean heating.
Agricultural mechanization and custom machine services have developed rapidly in China, which can influence rice production efficiency in the future. We calculate technical efficiency, allocative ...efficiency, and scale efficiency using data collected in 2015 from a face-to-face interview survey of 450 households that cultivated 3096 plots located in the five major rice-producing provinces of China. We use a one-step stochastic frontier model to calculate technical efficiency and regress the efficiency scores on socio-demographic and physical land characteristics to find the influencing variables. Variables influencing technical efficiency are compared at three different phases of rice cultivation. We also calculate technical efficiency by using the Heckman Selection Model, which addresses technological heterogeneity and self-selection bias. Results indicate that: (1) the average value of technical efficiency using a one-step stochastic frontier model was found to be 0.74. When self-selection bias is accounted for using the Heckman Selection Model, the average value of the technical efficiency increases to 0.80; (2) mechanization at the chemical application phase has a positive effect on technical efficiency, but mechanization does not affect efficiency at the plowing and harvesting phases; (3) machines are overused relative to both land and labor, and high machine input use on the small size of landholding has resulted in allocative inefficiency; (4) rice farmers are overwhelmingly operating at a sub-optimal scale. Future policies should focus on encouraging farmland transfer in rural areas to achieve scale efficiency and allocative efficiency while promoting mechanization at the chemical application phase of rice cultivation to improve technical efficiency.
A novel palladium‐catalyzed CO‐gas‐ and autoclave‐free protocol for the synthesis of 11H‐pyrido2,1‐bquinazolin‐11‐ones has been developed. Quinazolinones, which are omnipresent motif in many ...pharmaceuticals and agrochemicals, were prepared in good yields by CH bond activation and annulation using DMF as the CO surrogate. A 13CO‐labelled DMF control experiment demonstrated that CO gas was released from the carbonyl of DMF with acid as the promotor. The kinetic isotope effect (KIE) value indicated that the CH activation step may not be involved in the rate‐determining step. This methodology is operationally simple and showed a broad substrate scope with good to excellent yields.
When DMF meets TFA: A novel palladium‐catalyzed CO‐gas and autoclave‐free procedure for the synthesis of 11H‐pyrido2,1‐bquinazolin‐11‐one using DMF as a CO surrogate has been developed (see scheme). 13CO‐labelled DMF and control experiments demonstrate that CO gas could be released from easily available and cheap DMF with the aid of an acid. The kinetic isotope effect (KIE) value indicates that the CH activation step may not be involved in the rate‐determining step. The reaction conditions displayed good functional group tolerance, and the desired products were isolated in good yields.
Biodegradable magnesium‐based scaffolds present outstanding potential to revolutionize the treatment of coronary artery diseases, in which full recovery of arteries without long‐term irritation of ...implants is anticipated for averting adverse events associated with the permanent stents. However, overfast degradation of magnesium (Mg) alloys obstructs their extensive applications in terms of early structural failure and impaired biocompatibility. Herein, a facile copper‐incorporated coating system through nonaqueous phase synthesis of polydopamine is developed to facilitate Cu(II) capture along with robust film deposited on easily corrodible Mg, which subsequently enables sustained Cu(II) elution. It remarkably enhances corrosion resistance and impedes Mg degradation, which also contributes to improved, superior cytocompatibility, and abolished hemolysis. Moreover, through simultaneous control of Cu(II) and Mg(II) release to modulate the local microenvironment, a synergistic biochemical effect on desirable vascular cell selectivity is triggered for boosted endothelial cell viability and suppressed smooth muscle cell. Stent implantation into rabbit abdominal aorta thus exhibits accelerated re‐endothelialization completed in a week, and enhanced biological outcomes, alleviated complications and prolonged structural durability in 3‐month follow‐up. Collectively, this study opens up an alternative route of deploying a multifunctional surface modification strategy tailoring active interplay with the Mg matrix for better outcomes of next‐generation bioresorbable vascular stents.
With modulation effect on vessel microenvironment, coatings capable of active interaction with biodegradable matrix make significant difference on bioresorbable vascular stent performance. Cu(II)/polydopamine coating on magnesium is constructed through nonaqueous phase polymerization and demonstrates enhanced corrosion resistance for magnesium stent. It also triggers synergistic bioeffect of released Cu(II) and Mg(II) on vascular cells selectivity, thus promoting endothelialization while alleviating restenosis.
The aim of the study was to better understand the genetic characteristics of the Miao group in China. Herein, genetic characteristics and forensic application values of 57 autosomal ...insertion–deletion (InDel) loci were investigated in 210 unrelated healthy individuals from the Chinese Yunnan Miao (YM) group. Meanwhile, the genetic differences in these InDels were compared among the YM group and 26 reference populations. The results of forensic statistical analyses showed that all 57 autosomal InDels were in accordance with the Hardy–Weinberg and linkage equilibria of pairwise loci in the Chinese YM group. Moreover, the combined probability of discrimination and probability of exclusion in the YM group were 0.9999999999999999999999801 and 0.999928, respectively, which indicated that the multiplex amplification including 57 autosomal InDels was suitable for forensic individual identification and paternity testing in the Chinese YM group. In addition, the results of allelic frequency distribution differential analyses, principal component analyses, phylogenetic tree reconstruction, and genetic structure analyses between the Chinese YM group and 26 reference populations revealed that the genetic similarities between the YM group and East Asian populations were more than that between the YM group and other geographical populations. This 57 autosomal InDels system can also effectively distinguish East Asian, European, and African populations.
•Sodium oleate has collecting ability for both scheelite and calcite.•Acidified sodium silicate is mixture of sodium silicate and oxalic acid with a ratio of 3:1.•Acidified sodium silicate exhibits ...selective depression for calcite.•The separation of scheelite from calcite is realized.
The flotation separation of scheelite from calcite using sodium oleate as collector and acidified sodium silicate as depressant has been studied. The results show that sodium oleate has collecting ability to both scheelite and calcite and the flotation separation of scheelite from calcite cannot be realized if collector is used only. The depressant acidified sodium silicate has selective depression effect on calcite and the optimum ratio of sodium silicate to oxalic is 3:1. The use of acidified sodium silicate as depressant can achieve the flotation separation of scheelite from calcite. Infrared studies and zeta potential measurements showed that the pre-adsorption of acidified sodium silicate interferes with the adsorption of sodium oleate on calcite surface while does not interfere with its adsorption on scheelite surface.
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bstract
We generalize Integration-By-Parts (IBP) and differential equations methods to de Sitter correlators related to inflation. While massive correlators in de Sitter spacetime are usually ...regarded as highly intricate, we find they have remarkably hidden concise structures from the perspective of IBP. We find the factorization of the IBP relations of each vertex integral family corresponding to d
τ
i
integration. Furthermore, with a smart construction of master integrals, the universal formulas for iterative reduction and d log-form differential equations of arbitrary vertex integral family are presented and proved. These formulas dominate all tree-level de Sitter correlators and play a kernel role at the loop-level as well.
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bstract
In this paper, we develop an iterative sector-level reduction strategy for Feynman integrals, which bases on module intersection in the Baikov representation and auxiliary vector for tensor ...structure. Using this strategy we have studied the reduction of general one-loop integrals, i.e., integrals having arbitrary tensor structures and arbitrary power for propagators. Inspired by these studies, a uniform and compact formula that iteratively reduces all one-loop integrals has been written down, where messy polynomials in integration-by-parts (IBP) relations have organized themselves to Gram determinants.
The MYB superfamily constitutes one of the most abundant groups of transcription factors described in plants. Nevertheless, their functions appear to be highly diverse and remain rather unclear. To ...date, no genome-wide characterization of this gene family has been conducted in a legume species. Here we report the first genome-wide analysis of the whole MYB superfamily in a legume species, soybean (Glycine max), including the gene structures, phylogeny, chromosome locations, conserved motifs, and expression patterns, as well as a comparative genomic analysis with Arabidopsis.
A total of 244 R2R3-MYB genes were identified and further classified into 48 subfamilies based on a phylogenetic comparative analysis with their putative orthologs, showed both gene loss and duplication events. The phylogenetic analysis showed that most characterized MYB genes with similar functions are clustered in the same subfamily, together with the identification of orthologs by synteny analysis, functional conservation among subgroups of MYB genes was strongly indicated. The phylogenetic relationships of each subgroup of MYB genes were well supported by the highly conserved intron/exon structures and motifs outside the MYB domain. Synonymous nucleotide substitution (dN/dS) analysis showed that the soybean MYB DNA-binding domain is under strong negative selection. The chromosome distribution pattern strongly indicated that genome-wide segmental and tandem duplication contribute to the expansion of soybean MYB genes. In addition, we found that ~ 4% of soybean R2R3-MYB genes had undergone alternative splicing events, producing a variety of transcripts from a single gene, which illustrated the extremely high complexity of transcriptome regulation. Comparative expression profile analysis of R2R3-MYB genes in soybean and Arabidopsis revealed that MYB genes play conserved and various roles in plants, which is indicative of a divergence in function.
In this study we identified the largest MYB gene family in plants known to date. Our findings indicate that members of this large gene family may be involved in different plant biological processes, some of which may be potentially involved in legume-specific nodulation. Our comparative genomics analysis provides a solid foundation for future functional dissection of this family gene.
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