EXISTENCE FOR CALCULUS OF VARIATIONS AND OPTIMAL CONTROL PROBLEMS ON TIME SCALES

1. Introduction. Continuous-time modelling and discrete-time modelling are two main approaches which dominate the methodology of mathematical modelling. System dynamics can be analyzed by using either approach. For example, both continuous-time recurrent neural networks and their discrete-time analogue have been studied in the literature (see, for example, [1] and the references therein). However, in practice, some processes consist of both continuous and discrete elements. A simple example of this kind of hybrid continuous-discrete time system is seasonally breeding population whose generations do not overlap. Temperate zone insects (including many economically important crop and orchid pests) are of this kind. These insects lay their eggs just before the generation dies out at the end of the season, with the eggs laying dormant, hatching at the start of the next season, and giving rise to a new, nonoverlapping generation. During each generation the population varies continuously (due to mortality, resource consumption, predation, interaction, etc.), while the population varies in a discrete fashion between the end of one generation and the beginning of the nex

Impact of thermal processing on dietary flavonoids

Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGFlavonoids are widely distributed in natural products and foods as a class of polyphenols. They processed diverse bioactivities, including anti-inflammation activity, antiaging activity, and antioxidant activity. The foods rich in flavonoids are usually consumed after thermal processing. However, flavonoids are commonly vulnerable under thermal processing, and it could cause various influences on their stability and bioactivities. Therefore, in this review, the effects of thermal processing on thermal stability and bioactivities of dietary flavonoids from different food sources were first summarized. The strategies to improve thermal stability of dietary flavonoids were then discussed. Noticeably, the effect of some of the promising thermal technologies on dietary flavonoids was also clarified preliminarily in the current review. The promising thermal technologies may be an alternative to conventional thermal processing technologies.Agencia Estatal de Investigación | Ref. RYC2020-030365-

Dynamic aperture factor analysis/target transformation (DAFA/TT) for Mg-serpentine and Mg-carbonate mapping on Mars with CRISM near-infrared data

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Lin, H., Tarnas, J. D., Mustard, J. F., Zhang, X., Wei, Y., Wan, W., Klein, F., & Kellner, J. R. Dynamic aperture factor analysis/target transformation (DAFA/TT) for Mg-serpentine and Mg-carbonate mapping on Mars with CRISM near-infrared data. Icarus, 355, (2021): 114168, https://doi.org/10.1016/j.icarus.2020.114168.Serpentine and carbonate are products of serpentinization and carbonation processes on Earth, Mars, and other celestial bodies. Their presence implies that localized habitable environments may have existed on ancient Mars. Factor Analysis and Target Transformation (FATT) techniques have been applied to hyperspectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) to identify possible serpentine and Mg-carbonate-bearing outcrops. FATT techniques are capable of suggesting the presence of individual spectral signals in complex spectral mixtures. Applications of FATT techniques to CRISM data thus far only evaluate whether an entire analyzed image (≈ 3 × 105 pixels) may contain spectral information consistent with a specific mineral of interest. The spatial distribution of spectral signal from the possible mineral is not determined, making it difficult to validate a reported detection and also to understand the geologic context of any purported detections. We developed a method called Dynamic Aperture Factor Analysis/Target Transformation (DAFA/TT) to highlight the locations in a CRISM observation (or any similar laboratory or remotely acquired data set) most likely to contain spectra of specific minerals of interest. DAFA/TT determines the locations of possible target mineral spectral signals within hyperspectral images by performing FATT in small moving windows with different geometries, and only accepting pixels with positive detections in all cluster geometries as possible detections. DAFA/TT was applied to a hyperspectral image of a serpentinite from Oman for validation testing in a simplified laboratory setting. The mineral distribution determined by DAFA/TT application to the laboratory hyperspectral image was consistent with Raman analysis of the serpentinite sample. DAFA/TT also successfully mapped the spatial distribution of Mg-serpentine and Mg-carbonate previously detected in CRISM data using band parameter mapping and extraction of ratioed spectra. We applied DAFA/TT to CRISM images in some olivine-rich regions of Mars to characterize the spatial distribution of Mg-serpentine and Mg-carbonate-bearing outcrops.This work was supported by the National Natural Science Foundation of China (grant no. 41671360, 41525016, 41902318). JFM and JDT acknowledge NASA support through a subcontract from the Applied Physics Lab for CRISM investigations. H. Lin also acknowledges the support from the key research Program of the Institute of Geology and Geophysics, CAS (IGGCAS-201905). The Headwall imaging spectrometer was acquired using funds to JRK from The Institute at Brown for Environment and Society and Brown University. The DAFA/TT codes are available on GitHub (https://github.com/linhoml?tab=repositories)

Novel sequences of subgroup J avian leukosis viruses associated with hemangioma in Chinese layer hens

<p>Abstract</p> <p>Background</p> <p>Avian leukosis virus subgroup J (ALV-J) preferentially induces myeloid leukosis (ML) in meat-type birds. Since 2008, many clinical cases of hemangioma rather than ML have frequently been reported in association with ALV-J infection in Chinese layer flocks.</p> <p>Results</p> <p>Three ALV-J strains associated with hemangioma were isolated and their proviral genomic sequences were determined. The three isolates, JL093-1, SD09DP03 and HLJ09MDJ-1, were 7,670, 7,670, and 7,633 nt in length. Their gag and pol genes were well conserved, with identities of 94.5-98.6% and 97.1-99.5%, respectively, with other ALV-J strains at the amino acid level (aa), while the env genes of the three isolates shared a higher aa identity with the env genes of other hemangioma strains than with those of ML strains. Interestingly, two novel 19-bp insertions in the U3 region in the LTR and 5' UTR, most likely derived from other retroviruses, were found in all the three isolates, thereby separately introducing one E2BP binding site in the U3 region in the LTR and RNA polymerase II transcription factor IIB and core promoter motif ten elements in the 5' UTR. Meanwhile, two binding sites in the U3 LTRs of the three isolates for NFAP-1 and AIB REP1 were lost, and a 1-base deletion in the E element of the 3' UTR of JL093-1 and SD09DP03 introduced a binding site for c-Ets-1. In addition to the changes listed above, the rTM of the 3' UTR was deleted in each of the three isolates.</p> <p>Conclusion</p> <p>Our study is the first to discovery the coexistence of two novel insertions in the U3 region in the LTR and the 5' UTR of ALV-J associated with hemangioma symptoms, and the transcriptional regulatory elements introduced should be taken into consideration in the occurrence of hemangioma.</p

Autonomous concrete crack semantic segmentation using deep fully convolutional encoder-decoder network in concrete structures inspection

Structure health inspection is the way to ensure that structures stay in optimum condition. Traditional inspection work has many disadvantages in dealing with the large workload despite using remote image-capturing devices. This research focuses on image-based concrete crack pattern recognition utilizing a deep convolutional neural network (DCNN) and an encoder–decoder module for semantic segmentation and classification tasks, thereby lightening the inspectors’ workload. To achieve this, a series of contrast experiments have been implemented. The results show that the proposed deep-learning network has competitive semantic segmentation accuracy (91.62%) and over-performs compared with other crack detection studies. This proposed advanced DCNN is split into multiple modules, including atrous convolution (AS), atrous spatial pyramid pooling (ASPP), a modified encoder–decoder module, and depthwise separable convolution (DSC). The advancement is that those modules are well-selected for this task and modified based on their characteristics and functions, exploiting their superiority to achieve robust and accurate detection globally. This application improved the overall performance of detection and can be implemented in industrial practices

Ethylene-Induced Hydrogen Sulfide Negatively Regulates Ethylene Biosynthesis by Persulfidation of ACO in Tomato Under Osmotic Stress

A number of recent studies identified hydrogen sulfide (H2S) as an important signal in plant development and adaptation to environmental stress. H2S has been proven to participate in ethylene-induced stomatal closure, but how the signaling pathways of H2S and ethylene interact is still unclear. Here, we reveal how H2S controls the feedback-regulation of ethylene biosynthesis in tomato (Solanum lycopersicum) under osmotic stress. We found that ethylene induced the production of H2S in guard cells. The supply of hypotaurine (HT; a H2S scavenger) or DL-pro-pargylglycine (PAG; a synthetic inhibitor of H2S) removed the effect of ethylene or osmotic stress on stomatal closure. This suggests that ethylene-induced H2S is a downstream component of osmotic stress signaling, which is required for ethylene-induced stomatal closure under osmotic stress. We further found that H2S inhibited ethylene synthesis through inhibiting the activity of 1-aminocyclopropane-1-carboxylic acid (ACC) oxidases (ACOs) by persulfidation. A modified biotin-switch method (MBST) showed that H2S can induce persulfidation of LeACO1 and LeACO2 in a dose-dependent manner, and that persulfidation inhibits the activity of LeACO1 and LeACO2. We also found that LeACO1 is persulfidated at cysteine 60. These data suggested that ethylene-induced H2S negatively regulates ethylene biosynthesis by persulfidation of LeACOs. In addition, H2S was also found to inhibit the expression of LeACO genes. The results provide insight on the general mode of action of H2S and contribute to a better understanding of a plant’s response to osmotic stress