Endogenous Matching and Contractual Choice between Agricultural Processors and Farmers in China

Contracts are widely used by agricultural processors for purchasing inputs not only in developed countries but also in developing countries such as China. The total number of formal, written contracts between farmers and food processors is increasing rapidly in China, and the formal contracts that exist are becoming more complex. Contractual design in China is evolving from simple price-quantity contracts toward more complicated arrangements known as cooperation contracts or joint-stock cooperation contracts, designed to share risk and mitigate opportunistic behaviors by the contracting parties. Due to small farm sizes, the contracted amount in the typical contract in China is very small compared with Western countries, and each processor usually has a large number of contracted farmers. This paper uses data from a 2003 survey of food processing firms by the Chinese Ministry of Agriculture to analyze the determinants of contractual choices between these firms and farmers and the number of farmers that each firm contracts with. An important issue identified in the literature in analyzing the determinants of contractual choices is endogenous matching between parties to a contract and the effects of this endogenous matching on contract choice. We find strong evidence to support endogenous matching. In particular, our results indicate that firms which contract with a larger number of farms are more likely to use cooperation contracts than relational contracts.China, contractual design, endogenous matching, farms, food processing, Agribusiness, Industrial Organization, Q13, L14,

Puerarin affects bone biomarkers in the serum of rats with intrauterine growth restriction

AbstractObjectiveTo investigate serum bone biomarkers in rats with intrauterine growth restriction (IUGR) in order to determine the effects of puerarin on bone metabolism.MethodsA rat model of IUGR was induced using a low protein diet during pregnancy. The offspring were given puerarin or an identical volume of saline via subcutaneous abdominal injection. All rats were studied at 1,3, and 8 weeks of age. Serum biomarkers of bone formation, including insulin-like growth factor-1 (IGF-1), bone-specific alkaline phosphatase (BALP), osteocalcin (OC), osteoprotegerin (OPG), receptor-activator of nuclear factor-KB ligand (RANKL), as well as blood levels of calcium and phosphorus were measured.ResultsSerum BALP, OPG, IGF-1, and OC levels, as well as the OPG/RANKL ratio, were lower in the IUGR group compared with the control group at 1 week of age (P = 0.024, 0.011, 0.014, 0.004, and 0.002, respectively). At 3 weeks of age, the serum BALP and OC levels were higher in the protein-restricted group compared with the control group (P = 0.003 and 0.001, respectively). A comparison between the IUGR plus puerarin intervention group and the IUGR group revealed differences in the levels of BALP and IGF-1 at 3 weeks of age (P = 0.008 and 0.003, respectively). In addition, serum OPG and OC levels and the OPG/RANKL ratio were higher at 8 weeks of age (P = 0.044, 0.007, and 0.016, respectively). No differences in serum calcium and phosphorus levels were observed among the three groups.ConclusionOur study demonstrates that the bone microenvironment of the fetus can be altered by a low protein maternal diet and that puerarin can reverse these effects. These results indicate that the nutritional environment plays an important role in early skeletal development and that the bone turnover of IUGR rats can be altered by puerarin treatment

Statistical and Biological Evaluation of Different Gene Set Analysis Methods

AbstractGene-set analysis (GSA) methods have been widely used in microarray data analysis. Owing to the unusual characteristics of microarray data, such as multi-dimension, small sample size and complicated relationship between genes, no generally accepted methods have been used to detect differentially expressed gene sets (DEGs) up to now. Our group assessed the statistical performance of some commonly used methods through Monte Carlo simulation combined with the analysis of real-world microarray data sets. Not only did we discover a few novel features of GSA methods during experiences, but also we find that some GSA methods are effective only if genes were assumed to be independent. And we also detected that model-based methods (GlobalTest and PCOT2) performed well when analyzing our simulated data sets in which the inter-gene correlation structure was incorporated into each gene set separately for more reasonable. Through analysis of real-world microarray data, we found GlobalTest is more effective. Then we concluded that GlobalTest is a more effective gene set analysis method, and recommended using it with microarray data analysis

Performing group-level functional image analyses based on homologous functional regions mapped in individuals

Functional MRI (fMRI) studies have traditionally relied on intersubject normalization based on global brain morphology, which cannot establish proper functional correspondence between subjects due to substantial intersubject variability in functional organization. Here, we reliably identified a set of discrete, homologous functional regions in individuals to improve intersubject alignment of fMRI data. These functional regions demonstrated marked intersubject variability in size, position, and connectivity. We found that previously reported intersubject variability in functional connectivity maps could be partially explained by variability in size and position of the functional regions. Importantly, individual differences in network topography are associated with individual differences in task-evoked activations, suggesting that these individually specified regions may serve as the localizer to improve the alignment of task-fMRI data. We demonstrated that aligning task-fMRI data using the regions derived from resting state fMRI may lead to increased statistical power of task-fMRI analyses. In addition, resting state functional connectivity among these homologous regions is able to capture the idiosyncrasies of subjects and better predict fluid intelligence (gF) than connectivity measures derived from group-level brain atlases. Critically, we showed that not only the connectivity but also the size and position of functional regions are related to human behavior. Collectively, these findings suggest that identifying homologous functional regions across individuals can benefit a wide range of studies in the investigation of connectivity, task activation, and brain-behavior associations. Author summary No two individuals are alike. The size, shape, position, and connectivity patterns of brain functional regions can vary drastically between individuals. While interindividual differences in functional organization are well recognized, to date, standard procedures for functional neuroimaging research still rely on aligning different subjects' data to a nominal average brain based on global brain morphology. We developed an approach to reliably identify homologous functional regions in each individual and demonstrated that aligning data based on these homologous functional regions can significantly improve the study of resting state functional connectivity, task-fMRI activations, and brain-behavior associations. Moreover, we showed that individual differences in size, position, and connectivity of brain functional regions are dissociable, and each can provide nonredundant information in explaining human behavior

Peculiar optical properties of bilayer silicene under the influence of external electric and magnetic fields

We conduct a comprehensive investigation of the effect of an applied electric field on the optical and magneto-optical absorption spectra for AB-bt (bottom-top) bilayer silicene. The generalized tightbinding model in conjunction with the Kubo formula is efficiently employed in the numerical calculations. The electronic and optical properties are greatly diversified by the buckled lattice structure, stacking configuration, intralayer and interlayer hopping interactions, spin-orbital couplings, as well as the electric and magnetic fields (Ez ˆz & Bz ˆz ). An electric field induces spin-split electronic states, a semiconductor-metal phase transitions and the Dirac cone formations in different valleys, leading to the special absorption features. The Ez-dependent low-lying Landau levels possess lower degeneracy, valley-created localization centers, peculiar distributions of quantum numbers, well-behaved and abnormal energy spectra in Bz-dependencies, and the absence of anti-crossing behavior. Consequently, the specific magneto-optical selection rules exist for diverse excitation categories under certain critical electric fields. The optical gaps are reduced as Ez is increased, but enhanced by Bz, in which the threshold channel might dramatically change in the former case. These characteristics are in sharp contrast with those for layered graphene

CRISPR-Cas13 in malaria parasite: Diagnosis and prospective gene function identification

Malaria caused by Plasmodium is still a serious public health problem. Genomic editing is essential to understand parasite biology, elucidate mechanical pathways, uncover gene functions, identify novel therapeutic targets, and develop clinical diagnostic tools. Recent advances have seen the development of genomic diagnostic technologies and the emergence of genetic manipulation toolbox comprising a host of several systems for editing the genome of Plasmodium at the DNA, RNA, and protein level. Genomic manipulation at the RNA level is critical as it allows for the functional characterization of several transcripts. Of notice, some developed artificial RNA genome editing tools hinge on the endogenous RNA interference system of Plasmodium. However, Plasmodium lacks a robust RNAi machinery, hampering the progress of these editing tools. CRISPR-Cas13, which belongs to the VI type of the CRISPR system, can specifically bind and cut RNA under the guidance of crRNA, with no or minimal permanent genetic scar on genes. This review summarizes CRISPR-Cas13 system from its discovery, classification, principle of action, and diagnostic platforms. Further, it discusses the application prospects of Cas13-based systems in Plasmodium and highlights its advantages and drawbacks

Curdlan Prevents the Cognitive Deficits Induced by a High-Fat Diet in Mice via the Gut-Brain Axis

A high-fat (HF) diet is a major predisposing factor of neuroinflammation and cognitive deficits. Recently, changes in the gut microbiota have been associated with neuroinflammation and cognitive impairment, through the gut-brain axis. Curdlan, a bacterial polysaccharide widely used as food additive, has the potential to alter the composition of the microbiota and improve the gut-brain axis. However, the effects of curdlan against HF diet-induced neuroinflammation and cognitive decline have not been investigated. We aimed to evaluate the neuroprotective effect and mechanism of dietary curdlan supplementation against the obesity-associated cognitive decline observed in mice fed a HF diet. C57Bl/6J male mice were fed with either a control, HF, or HF with curdlan supplementation diets for 7 days (acute) or 15 weeks (chronic). We found that acute curdlan supplementation prevented the gut microbial composition shift induced by HF diet. Chronic curdlan supplementation prevented cognitive declines induced by HF diet. In addition, curdlan protected against the HF diet-induced abnormities in colonic permeability, hyperendotoxemia, and colonic inflammation. Furthermore, in the prefrontal cortex (PFC) and hippocampus, curdlan mitigated microgliosis, neuroinflammation, and synaptic impairments induced by a HF diet. Thus, curdlan-as a food additive and prebiotic-can prevent cognitive deficits induced by HF diet via the colon-brain axis