Sky reconstruction for the Tianlai cylinder array

In this paper, we apply our sky map reconstruction method for transit type interferometers to the Tianlai cylinder array. The method is based on the spherical harmonic decomposition, and can be applied to cylindrical array as well as dish arrays and we can compute the instrument response, synthesised beam, transfer function and the noise power spectrum. We consider cylinder arrays with feed spacing larger than half wavelength, and as expected, we find that the arrays with regular spacing have grating lobes which produce spurious images in the reconstructed maps. We show that this problem can be overcome, using arrays with different feed spacing on each cylinder. We present the reconstructed maps, and study the performance in terms of noise power spectrum, transfer function and beams for both regular and irregular feed spacing configurations.Comment: 15 pages, 12 figures, accepted by RA

Mapping and candidate-gene screening of the novel Turnip mosaic virus resistance gene retr02 in Chinese cabbage (Brassica rapa L.)

The extreme resistance to Turnip mosaic virus observed in the Chinese cabbage (Brassica rapa) line, BP8407, is monogenic and recessive. Bulked segregant analysis was carried out to identify simple sequence repeat and Indel markers linked to this recessive resistance gene, termed recessive Turnip mosaic virus resistance 02 (retr02). Mapping of PCR-specific Indel markers on 239 individuals of a BP8407 × Ji Zao Chun F 2 population, located this resistance gene to a 0.9-cM interval between two Indel markers (BrID10694 and BrID101309) and in scaffold000060 or scaffold000104 on chromosome A04 of the B. rapa genome. Eleven eukaryotic initiation factor 4E (eIF4E) and 14 eukaryotic initiation factor 4G (eIF4G) genes are predicted in the B. rapa genome. A candidate gene, Bra035393 on scaffold000104, was predicted within the mapped resistance locus. The gene encodes the eIF(iso)4E protein. Bra035393 was sequenced in BP8407 and Ji Zao Chun. A polymorphism (A/G) was found in exon 3 between BP8407 and Ji Zao Chun. This gene was analysed in four resistant and three susceptible lines. A correlation was observed between the amino acid substitution (Gly/Asp) in the eIF(iso)4E protein and resistance/susceptibility. eIF(iso)4E has been shown previously to interact with the TuMV genome-linked protein, VPg

Investigation on the Adsorption Mechanisms of Ionizable Compounds on Carbon Nanotubes

This study investigates the adsorption of several ionizable compounds on different types of carbon nanotubes, including graphitized multi-walled carbon nanotubes (G-CNTs), carboxyl functionalized multi-walled carbon nanotubes (COOH-CNTs) and hydroxyl functionalized multi-walled carbon nanotubes (OH-CNTs). The ionizable compounds investigated in this study are benzoic acid (BA), 2-naphthoic acid (2-NA), 3-hydroxy-2-naphthoic acid (3-H-2-NA), 3-methoxy-2-naphthoic acid (3-M-2-NA) and 3-amino-2-naphthoic acid (3-A-2-NA). Adsorption isotherms of BA on all three CNTs at pH 2 and pH 7 were measured and they are highly nonlinear. The maximum capacity of functionalized CNTs for BA was invariably higher than that of G-CNTs. The results agree with a previous report that benzoate displayed strong adsorption onto functionalized CNTs and is consistent with the assumption that the negative-charged H-bonds are formed during the adsorption. OH- stoichiometry confirmed that the adsorption of benzoate was accompanied with OH- release. In comparison, the adsorption of BA on G-CNTs at pH 2.0 is mostly attributed to the hydrophobic force. At pH 2, functionalized CNTs show a greater adsorption for BA than G-CNTs. The forming of hydrogen bonding between O-containing functional groups on CNTs and the oxygen on the carboxyl functional group on benzene rings was deemed as the main reason for the enhanced adsorption of functionalized CNTs. The sorption isotherms of NA at pH 2.0 and 7.0 displayed a similar adsorption patterns as BA. Hydrophobic forces play significant roles in the adsorption of the acids at pH 2.0. At pH 7.0, the adsorption of the base exhibited strong affinity to functionalized CNTs, suggesting that similar charge-assisted hydrogen bonding has been formed during adsorption. A comparison of hydroxide ion release from BA and NA adsorption on COOH-CNTs at pH 7.0 showed that the hydroxide release from NA almost overlaps with the hydroxide release for BA adsorption, suggesting that the molecular size doesn’t impact the forming of negative-charged H-bond. But the molecular structure did show a significant impact on the formation of this particularly strong intermolecular force

Investigation on the Adsorption Mechanisms of Ionizable Compounds on Carbon Nanotubes

This study investigates the adsorption of several ionizable compounds on different types of carbon nanotubes, including graphitized multi-walled carbon nanotubes (G-CNTs), carboxyl functionalized multi-walled carbon nanotubes (COOH-CNTs) and hydroxyl functionalized multi-walled carbon nanotubes (OH-CNTs). The ionizable compounds investigated in this study are benzoic acid (BA), 2-naphthoic acid (2-NA), 3-hydroxy-2-naphthoic acid (3-H-2-NA), 3-methoxy-2-naphthoic acid (3-M-2-NA) and 3-amino-2-naphthoic acid (3-A-2-NA). Adsorption isotherms of BA on all three CNTs at pH 2 and pH 7 were measured and they are highly nonlinear. The maximum capacity of functionalized CNTs for BA was invariably higher than that of G-CNTs. The results agree with a previous report that benzoate displayed strong adsorption onto functionalized CNTs and is consistent with the assumption that the negative-charged H-bonds are formed during the adsorption. OH- stoichiometry confirmed that the adsorption of benzoate was accompanied with OH- release. In comparison, the adsorption of BA on G-CNTs at pH 2.0 is mostly attributed to the hydrophobic force. At pH 2, functionalized CNTs show a greater adsorption for BA than G-CNTs. The forming of hydrogen bonding between O-containing functional groups on CNTs and the oxygen on the carboxyl functional group on benzene rings was deemed as the main reason for the enhanced adsorption of functionalized CNTs. The sorption isotherms of NA at pH 2.0 and 7.0 displayed a similar adsorption patterns as BA. Hydrophobic forces play significant roles in the adsorption of the acids at pH 2.0. At pH 7.0, the adsorption of the base exhibited strong affinity to functionalized CNTs, suggesting that similar charge-assisted hydrogen bonding has been formed during adsorption. A comparison of hydroxide ion release from BA and NA adsorption on COOH-CNTs at pH 7.0 showed that the hydroxide release from NA almost overlaps with the hydroxide release for BA adsorption, suggesting that the molecular size doesn’t impact the forming of negative-charged H-bond. But the molecular structure did show a significant impact on the formation of this particularly strong intermolecular force

Testing for jumps in a discretely observed price process with endogenous sampling times

This paper introduces a novel nonparametric high-frequency jump test for discretely observed Itô semimartingales. Based on observations sampled recursively at first exit times from a symmetric double barrier, our method distinguishes between threshold exceedances caused by the Brownian component and jumps, which enables the construction of a feasible, noise-robust statistical test. Simulation results demonstrate superior finite-sample performance of our test compared to existing methods. An empirical analysis of NYSE-traded stocks provides clear statistical evidence for jumps, with the results highly robust to spurious detections

Immunogenic cell death triggered by pathogen ligands via host germ line-encoded receptors

The strategic induction of cell death serves as a crucial immune defense mechanism for the eradication of pathogenic infections within host cells. Investigating the molecular mechanisms underlying immunogenic cell pathways has significantly enhanced our understanding of the host's immunity. This review provides a comprehensive overview of the immunogenic cell death mechanisms triggered by pathogen infections, focusing on the critical role of pattern recognition receptors. In response to infections, host cells dictate a variety of cell death pathways, including apoptosis, pyroptosis, necrosis, and lysosomal cell death, which are essential for amplifying immune responses and controlling pathogen dissemination. Key components of these mechanisms are host cellular receptors that recognize pathogen-associated ligands. These receptors activate downstream signaling cascades, leading to the expression of immunoregulatory genes and the production of antimicrobial cytokines and chemokines. Particularly, the inflammasome, a multi-protein complex, plays a pivotal role in these responses by processing pro-inflammatory cytokines and inducing pyroptotic cell death. Pathogens, in turn, have evolved strategies to manipulate these cell death pathways, either by inhibiting them to facilitate their replication or by triggering them to evade host defenses. This dynamic interplay between host immune mechanisms and pathogen strategies highlights the intricate co-evolution of microbial virulence and host immunity.Comment: 30 pages, 3 figure

A simulation of calibration and map-making errors of the Tianlai cylinder pathfinder array

The Tianlai cylinder array is a pathfinder for developing and testing 21cm intensity mapping techniques. In this paper, we use numerical simulation to assess how its measurement is affected by thermal noise and the errors in calibration and map-making process, and the error in the sky map reconstructed from a drift scan survey. Here we consider only the single frequency, unpolarized case. The beam is modelled by fitting to the electromagnetic simulation of the antenna, and the variations of the complex gains of the array elements are modelled by Gaussian processes. Mock visibility data is generated and run through our data processing pipeline. We find that the accuracy of the current calibration is limited primarily by the absolute calibration, where the error comes mainly from the approximation of a single dominating point source. We then studied the $m$-mode map-making with the help of Moore-Penrose inverse. We find that discarding modes with singular values smaller than a threshold could generate visible artifacts in the map. The impacts of the residue variation of the complex gain and thermal noise are also investigated. The thermal noise in the map varies with latitude, being minimum at the latitude passing through the zenith of the telescope. The angular power spectrum of the reconstructed map show that the current Tianlai cylinder pathfinder, which has a shorter maximum baseline length in the North-South direction, can measure modes up to $l \lesssim 2\pi b_{\rm NS}/\lambda \sim 200$ very well, but would lose a significant fraction of higher angular modes when noise is present. These results help us to identify the main limiting factors in our current array configuration and data analysis procedure, and suggest that the performance can be improved by reconfiguration of the array feed positions.Comment: 25 pages, 18 figures, RAA accepte

Carotenoid biosynthetic genes in Brassica rapa: comparative genomic analysis, phylogenetic analysis, and expression profiling

BACKGROUND: Carotenoids are isoprenoid compounds synthesized by all photosynthetic organisms. Despite much research on carotenoid biosynthesis in the model plant Arabidopsis thaliana, there is a lack of information on the carotenoid pathway in Brassica rapa. To better understand its carotenoid biosynthetic pathway, we performed a systematic analysis of carotenoid biosynthetic genes at the genome level in B. rapa. RESULTS: We identified 67 carotenoid biosynthetic genes in B. rapa, which were orthologs of the 47 carotenoid genes in A. thaliana. A high level of synteny was observed for carotenoid biosynthetic genes between A. thaliana and B. rapa. Out of 47 carotenoid biosynthetic genes in A. thaliana, 46 were successfully mapped to the 10 B. rapa chromosomes, and most of the genes retained more than one copy in B. rapa. The gene expansion was caused by the whole-genome triplication (WGT) event experienced by Brassica species. An expression analysis of the carotenoid biosynthetic genes suggested that their expression levels differed in root, stem, leaf, flower, callus, and silique tissues. Additionally, the paralogs of each carotenoid biosynthetic gene, which were generated from the WGT in B. rapa, showed significantly different expression levels among tissues, suggesting differentiated functions for these multi-copy genes in the carotenoid pathway. CONCLUSIONS: This first systematic study of carotenoid biosynthetic genes in B. rapa provides insights into the carotenoid metabolic mechanisms of Brassica crops. In addition, a better understanding of carotenoid biosynthetic genes in B. rapa will contribute to the development of conventional and transgenic B. rapa cultivars with enriched carotenoid levels in the future. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-015-1655-5) contains supplementary material, which is available to authorized users