89 research outputs found

    Surjective endomorphisms of projective surfaces -- the existence of infinitely many dense orbits

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    Let f ⁣:XXf \colon X \to X be a surjective endomorphism of a normal projective surface. When degf2\operatorname{deg} f \geq 2, applying an (iteration of) ff-equivariant minimal model program (EMMP), we determine the geometric structure of XX. Using this, we extend the second author's result to singular surfaces to the extent that either XX has an ff-invariant non-constant rational function, or ff has infinitely many Zariski-dense forward orbits; this result is also extended to Adelic topology (which is finer than Zariski topology)

    Review Helpfulness as a Function of discrete negative emotions and image colorfulness

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    Given that helpful reviews are valuable to both customers and e-commerce platforms, a better understanding of the antecedents for review helpfulness offers clear benefits to review writers and online vendors. This paper proposes two research questions: How will negative discrete emotions expressed through review text (i.e., fear, anger, sadness, and disgust) influence review helpfulness? And how will review textual emotions and image colorfulness of review interactively influence review helpfulness? Using online review of computer related products sold via Amazon in the past five years, we found that anger increase online review helpfulness, while sadness and disgust decrease the helpfulness. We also found the moderating effects of review image colorfulness on the relationship between discrete emotions and online review helpfulness. Our research advances the existing online review literature by proposing the importance of discrete emotions and its interactive effect with review image colorfulness in review helpfulness

    Endomorphisms of quasi-projective varieties -- towards Zariski dense orbit and Kawaguchi-Silverman conjectures

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    Let XX be a quasi-projective variety and f ⁣:XXf\colon X\to X a finite surjective endomorphism. We consider Zariski Dense Orbit Conjecture (ZDO), and Adelic Zariski Dense Orbit Conjecture (AZO). We consider also Kawaguchi-Silverman Conjecture (KSC) asserting that the (first) dynamical degree d1(f)d_1(f) of ff equals the arithmetic degree αf(P)\alpha_f(P) at a point PP having Zariski dense ff-forward orbit. Assuming XX is a smooth affine surface, such that the log Kodaira dimension κˉ(X)\bar{\kappa}(X) is non-negative (resp. the \'etale fundamental group π1eˊt(X)\pi_1^{\text{\'et}}(X) is infinite), we confirm AZO, (hence) ZDO, and KSC (when deg(f)2\operatorname{deg}(f)\geq 2) (resp. AZO and hence ZDO). We also prove ZDO (resp. AZO and hence ZDO) for every surjective endomorphism on any projective variety with ''larger'' first dynamical degree (resp. every dominant endomorphism of any semiabelian variety).Comment: 35 pages; comments are welcome

    FoodGPT: A Large Language Model in Food Testing Domain with Incremental Pre-training and Knowledge Graph Prompt

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    Currently, the construction of large language models in specific domains is done by fine-tuning on a base model. Some models also incorporate knowledge bases without the need for pre-training. This is because the base model already contains domain-specific knowledge during the pre-training process. We build a large language model for food testing. Unlike the above approach, a significant amount of data in this domain exists in Scanning format for domain standard documents. In addition, there is a large amount of untrained structured knowledge. Therefore, we introduce an incremental pre-training step to inject this knowledge into a large language model. In this paper, we propose a method for handling structured knowledge and scanned documents in incremental pre-training. To overcome the problem of machine hallucination, we constructe a knowledge graph to serve as an external knowledge base for supporting retrieval in the large language model. It is worth mentioning that this paper is a technical report of our pre-release version, and we will report our specific experimental data in future versions

    Processes regulating progressive nitrogen limitation under elevated carbon dioxide: a meta-analysis

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    The nitrogen (N) cycle has the potential to regulate climate change through its influence on carbon (C) sequestration. Although extensive research has explored whether or not progressive N limitation (PNL) occurs under CO2 enrichment, a comprehensive assessment of the processes that regulate PNL is still lacking. Here, we quantitatively synthesized the responses of all major processes and pools in the terrestrial N cycle with meta-analysis of CO2 experimental data available in the literature. The results showed that CO2 enrichment significantly increased N sequestration in the plant and litter pools but not in the soil pool, partially supporting one of the basic assumptions in the PNL hypothesis that elevated CO2 results in more N sequestered in organic pools. However, CO2 enrichment significantly increased the N influx via biological N fixation and the loss via N2O emission, but decreased the N efflux via leaching. In addition, no general diminished CO2 fertilization effect on plant growth was observed over time up to the longest experiment of 13 years. Overall, our analyses suggest that the extra N supply by the increased biological N fixation and decreased leaching may potentially alleviate PNL under elevated CO2 conditions in spite of the increases in plant N sequestration and N2O emission. Moreover, our syntheses indicate that CO2 enrichment increases soil ammonium (NH4+) to nitrate (NO3−) ratio. The changed NH4+/NO3− ratio and subsequent biological processes may result in changes in soil microenvironments, above-belowground community structures and associated interactions, which could potentially affect the terrestrial biogeochemical cycles. In addition, our data synthesis suggests that more long-term studies, especially in regions other than temperate ones, are needed for comprehensive assessments of the PNL hypothesis.This study was financially supported by the US Department of Energy, Terrestrial Ecosystem Sciences grant DE SC0008270 and Biological Systems Research on the Role of Microbial Communities in Carbon Cycling Program grants DE-SC0004601 and DE-SC0010715.Ye

    Proteomics study of changes in soybean lines resistant and sensitive to Phytophthora sojae

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    <p>Abstract</p> <p>Background</p> <p><it>Phytophthora sojae </it>causes soybean root and stem rot, resulting in an annual loss of 1-2 billion US dollars in soybean production worldwide. A proteomic technique was used to determine the effects on soybean hypocotyls of infection with <it>P. sojae</it>.</p> <p>Results</p> <p>In the present study, 46 differentially expressed proteins were identified in soybean hypocotyls infected with <it>P. sojae</it>, using two-dimensional electrophoresis and matrix-assisted laser desorption/ionization tandem time of flight (MALDI-TOF/TOF). The expression levels of 26 proteins were significantly affected at various time points in the tolerant soybean line, Yudou25, (12 up-regulated and 14 down-regulated). In contrast, in the sensitive soybean line, NG6255, only 20 proteins were significantly affected (11 up-regulated and 9 down-regulated). Among these proteins, 26% were related to energy regulation, 15% to protein destination and storage, 11% to defense against disease, 11% to metabolism, 9% to protein synthesis, 4% to secondary metabolism, and 24% were of unknown function.</p> <p>Conclusion</p> <p>Our study provides important information on the use of proteomic methods for studying protein regulation during plant-oomycete interactions.</p

    Construction and Analysis of Ecological Security Patterns in the Southern Anhui Region of China from a Circuit Theory Perspective

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    Located in an important biodiversity conservation area in the Yangtze River Delta, the habitats of many species have been severely eroded because of human activities such as tourism development. There is no relevant species conservation plan in place in the region, and scientific guidance on ecosystem change and corridor construction is urgently needed. In this study, we first assess ecosystem service functions based on the InVEST model; then, we assess ecological sensitivity and identify landscape resistance surfaces by constructing ecosystem sensitivity indicators; finally, we construct ecological security patterns by combining landscape resistance surfaces and circuit theory identification. The main results are as follows: (1) The high value area of ecosystem services is located in the southwest, while the northeast part of the study area has lower ecosystem services, and there is a trade-off between the ecosystem services in the study area. (2) There are 38 ecological sources in southern Anhui, with a total area of more than 5742.79 km2, that are the basic guarantees of ecological security, mainly located in the northeast of the study area, and woodland and grassland are the most important components, accounting for 18.4% of the total study area. (3) The ecological security pattern in the study area consists of 63 ecological sources, 37 important corridors, and 26 potential corridors, of which there are 28 pinch point areas and 6 barrier point patches in the study area, mainly located within Huangshan City and Xuancheng City. We recommend that when implementing restoration and rehabilitation measures in the future, policy makers should give priority to pinch points and barrier areas.</p

    Optimization Design of IGV Profile in Centrifugal Compressor

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    Variable inlet guide vane (IGV) is used to control the mass flow and generate prewhirl in centrifugal compressors. The efficient operation of IGV is limited to the range of aerodynamic characteristics of their vane profiles. In order to find out the best vane profile for IGV regulation, the modern optimization method was adopted to optimize the inlet guide vane profile. The main methodology idea was to use artificial neural network for continuous fitness evaluation and use genetic algorithm for global optimization. After optimization, the regulating performance of IGV has improved significantly, the prewhirl ability has been enhanced greatly, and the pressure loss has been reduced. The mass flow and power of compressor reduced by using the optimized guide vane at large setting angles, and the efficiency increased significantly; the flow field distribution has been improved obviously, since the nonuniform distribution of flow and flow separation phenomenon greatly weakened or even completely disappeared. The achievement of this research can effectively improve the regulation ability of IGV and the performance of compressor
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