159 research outputs found

    Abelianizing vertex algebras

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    To every vertex algebra VV we associate a canonical decreasing sequence of subspaces and prove that the associated graded vector space gr(V)gr(V) is naturally a vertex Poisson algebra, in particular a commutative vertex algebra. We establish a relation between this sequence and the sequence CnC_{n} introduced by Zhu. By using the (classical) algebra gr(V)gr(V), we prove that for any vertex algebra VV, C2C_{2}-cofiniteness implies CnC_{n}-cofiniteness for all n2n\ge 2. We further use gr(V)gr(V) to study generating subspaces of certain types for lower truncated ZZ-graded vertex algebras.Comment: Latex, 24 page

    Research on Emergency Logistics Model of Agricultural Products Based on Coupling of Petri Net and Blockchain

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    In this COVID-19 epidemic, due to insufficient awareness of the impact of sudden public health emergencies on agricultural logistics at this stage, agricultural products were left unsold, stocks were backlogged, and losses were severe. In the process of distribution, we should not only ensure a short time cycle and avoid the contamination of agricultural products by foreign bacteria, but also pay attention to the waste of human, material, and financial resources. Therefore, this study mainly adopts the combination of the petrochemical network and block chain to build an agricultural products emergency logistics model. This paper first shows the operation mechanism of the petri dish network and blockchain coupling in the form of a graph and then uses the culture network modelling and simulation tool PIPE to directly verify the construction model. It is proved that the structure and overall business process of the agricultural products logistics system constructed by combining the Petri net and block chain are reasonable, reliable, and feasible in practical application and development. It is hoped that this study can provide a reference direction for agricultural emergency logistics

    Emissions of Greenhouse Gases from a Typical Chinese Swine Farrowing Barn

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    Emissions of greenhouse gases (GHGs) from animal feeding operations to the atmosphere are of environmental importance and concerns because of their impact on global warming. Gaseous concentrations and emission rates (ERs) of animal facilities can be affected by the animal production stages, animal species, dietary nutrition, housing types, manure handling schemes, and environmental conditions. This article reports ERs of methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) for a typical, naturally ventilated 24-crate swine farrowing barn located in suburban Beijing, China, that was monitored over one-year period. The measurements were made at bi-monthly intervals (i.e., six measurement episodes total), with each measurement episode covering three consecutive days. Gaseous concentrations were monitored at bi-hourly intervals throughout each 3-day measurement episode. The ventilation rate of the barn was estimated using the CO2 mass balance method. The GHG concentrations and ERs of the farrowing barn showed diurnal and seasonal variations. Specifically, the concentrations (monthly mean ±SD, mg m-3) ranged from 2.3 (±0.3) to 9.3 (±2) for CH4, from 0.6 (±0.02) to 1.2 (±0.16) for N2O, and from 1,370 (±163) to 11,100 (±950) for CO2, with the higher levels occurring in January and the lower levels in July. The specific ER ranged from 95.2 to 261.8 mg h-1 pig-1 for CH4, from 6.4 to 12.9 mg h-1 pig-1 for N2O, and from 122.9 to 127.3 g h-1 pig-1 for CO2. On the basis of per animal unit (1 AU = 500 kg live body mass), the average daily ERs of the farrowing barn were 9.6 ±3.6 g AU-1 d-1 for CH4, 0.54 ±0.15 g AU-1 d-1 for N2O, and 7.5±0.1 kg AU-1 d-1 for CO2. Results of the GHG ERs from this study differ markedly from the limited literature data collected primarily under European production systems and conditions. Results of the current study provide some baseline data on GHG ERs for swine farrowing operations, thus contributing to development or improvement of GHG emission inventory under the Chinese livestock production conditions

    Effects of epigallocatechin-3-gallate on bovine oocytes matured

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    Objective Epigallocatechin-3-gallate (EGCG) is a major ingredient of catechin polyphenols and is considered one of the most promising bioactive compounds in green tea because of its strong antioxidant properties. However, the protective role of EGCG in bovine oocyte in vitro maturation (IVM) has not been investigated. Therefore, we aimed to study the effects of EGCG on IVM of bovine oocytes. Methods Bovine oocytes were treated with different concentrations of EGCG (0, 25, 50, 100, and 200 μM), and the nuclear and cytoplasmic maturation, cumulus cell expansion, intracellular reactive oxygen species (ROS) levels, total antioxidant capacity, the early apoptosis and the developmental competence of in vitro fertilized embryos were measured. The mRNA abundances of antioxidant genes (nuclear factor erythriod-2 related factor 2 [NRF2], superoxide dismutase 1 [SOD1], catalase [CAT], and glutathione peroxidase 4 [GPX4]) in matured bovine oocytes were also quantified. Results Nuclear maturation which is characterized by first polar body extrusion, and cytoplasmic maturation characterized by peripheral and cortical distribution of cortical granules and homogeneous mitochondrial distribution were significantly improved in the 50 μM EGCG-treated group compared with the control group. Adding 50 μM EGCG to the maturation medium significantly increased the cumulus cell expansion index and upregulated the mRNA levels of cumulus cell expansion-related genes (hyaluronan synthase 2, tumor necrosis factor alpha induced protein 6, pentraxin 3, and prostaglandin 2). Both the intracellular ROS level and the early apoptotic rate of matured oocytes were significantly decreased in the 50 μM EGCG group, and the total antioxidant ability was markedly enhanced. Additionally, both the cleavage and blastocyst rates were significantly higher in the 50 μM EGCG-treated oocytes after in vitro fertilization than in the control oocytes. The mRNA abundance of NRF2, SOD1, CAT, and GPX4 were significantly increased in the 50 μM EGCG-treated oocytes. Conclusion In conclusion, 50 μM EGCG can improve the bovine oocyte maturation, and the protective role of EGCG may be correlated with its antioxidative property

    Effects of sea ice melt water input on phytoplankton biomass and community structure in the eastern Amundsen Sea

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    Sea ice melt water and circumpolar deep water (CDW) intrusion have important impacts on the ecosystem of the Amundsen Sea. In this study, samples of nutrients and phytoplankton pigments from nine stations in the eastern Amundsen Sea were collected during the austral summer. Based on in-situ hydrological observations, sea ice density data from satellite remote sensing, and chemical taxonomy calculations, the relationships between environmental factors and phytoplankton biomass and community structure were studied. The results showed that with increasing latitude, the contribution of sea ice melt water (MW%) and the stability of the water body increased, and the depth of the mixed layer (MLD) decreased. The integrated concentration of chlorophyll a (Chl-a) ranged from 21.4 mg·m−2 to 148.4 mg·m−2 (the average value was 35.7±53.4 mg·m−2). Diatoms (diatoms-A [Fragilariopsis spp., Chaetoceros spp., and Proboscia spp.] and diatoms-B [Pseudonitzschia spp.]) and Phaeocystis antarctica were the two most widely distributed phytoplankton groups and contributed 32%±16% and 28%±11%, respectively, of the total biomass. The contributions of Dinoflagellates, Chlorophytes, Cryptophytes, the high-iron group of P. antarctica, and Diatom group A were approximately 17%±8%, 15%±13%, 9%±6%, 5%±9%, and 3%±7%, respectively. The area with the highest phytoplankton biomass was located near the ice-edge region, with a short time lag (Tlag) between sampling and complete sea ice melt and a high MW%, while the area with the second-highest Chl-a concentration was located in the area affected by the upwelling of CDW, with thorough water mixing. Vertically, in the area with a short Tlag and a shallow MLD, the phytoplankton biomass and proportion of diatoms decreased rapidly with increasing water depth. In contrast, in the region with a long Tlag and limited CDW upwelling, the phytoplankton community was dominated by a relatively constant and high proportion of micro phytoplankton, and the phytoplankton biomass was low and relatively stable vertically. Generally, the phytoplankton community structure and biomass in the study area showed high spatial variation and were sensitive to environmental changes

    Role of Leptin in Mood Disorder and Neurodegenerative Disease

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    The critical regulatory role of leptin in the neuroendocrine system has been widely reported. Significantly, leptin can improve learning and memory, affect hippocampal synaptic plasticity, exert neuroprotective efficacy and reduce the risk of several neuropsychiatric diseases. In terms of depression, leptin could modulate the levels of neurotransmitters, neurotrophic factors and reverse the dysfunction in the hypothalamic-pituitary-adrenal axis (HPA). At the same time, leptin affects neurological diseases during the regulation of metabolic homeostasis. With regards to neurodegenerative diseases, leptin can affect them via neuroprotection, mainly including Alzheimer’s disease and Parkinson’s disease. This review will summarize the mechanisms of leptin signaling within the neuroendocrine system with respect to these diseases and discuss the therapeutic potential of leptin
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