156 research outputs found
The Weihai Observatory search for close-in planets orbiting giant stars
Planets are known to orbit giant stars, yet there is a shortage of planets
orbiting within ~0.5 AU (P<100 days). First-ascent giants have not expanded
enough to engulf such planets, but tidal forces can bring planets to the
surface of the star far beyond the stellar radius. So the question remains: are
tidal forces strong enough in these stars to engulf all the missing planets? We
describe a high-cadence observational program to obtain precise radial
velocities of bright giants from Weihai Observatory of Shandong University. We
present data on the planet host Beta Gem (HD 62509), confirming our ability to
derive accurate and precise velocities; our data achieve an rms of 7.3 m/s
about the Keplerian orbit fit. This planet-search programme currently receives
~100 nights per year, allowing us to aggressively pursue short-period planets
to determine whether they are truly absent.Comment: Accepted for publication in PAS
Dynamic Characteristics and Seismic Response Analysis of a Long-Span Steel-Box Basket-Handle Railway Arch Bridge
The inside oblique angle between the vertical plane and the arch rib has been shown to be one of the main factors influencing dynamic properties of long-span steel-box basket-handle arch bridges. Details related to the extent, that the inside oblique angle influenced the dynamic characteristics and the seismic response of the arch bridge under the combined longitudinal and vertical seismic excitation and under the combined lateral and vertical seismic excitation, were reported herein. Four oblique angles (0°, 3°, 4.8°, and 6°) were selected based on the arch ribs height and bridge deck width. Findings suggested that a larger inside oblique angle increased the structural stiffness and thus the part internal forces when subjected to seismic excitation. These findings also showed that, when similar structures were designed and seismic considerations were warranted, a suitable inside oblique angle to mitigate dynamic effects should be selected only using a comprehensive analysis. At the same time, traveling wave effect analysis indicated that it couldn’t be ignored when calculating the seismic response of long-span steel-box basket-handle arch bridges
Dynamic characteristics and seismic response analysis of a long-span steel-box basket-handle railway arch bridge
The inside oblique angle between the vertical plane and the arch rib has been shown to be one of the main factors influencing dynamic properties of long-span steel-box basket-handle arch bridges. Details related to the extent, that the inside oblique angle influenced the dynamic characteristics and the seismic response of the arch bridge under the combined longitudinal and vertical seismic excitation and under the combined lateral and vertical seismic excitation, were reported herein. Four oblique angles (0°, 3°, 4.8° and 6°) were selected based on the arch ribs height and bridge deck width. Findings suggested that a larger inside oblique angle increased the structural stiffness and thus the part internal forces when subjected to seismic excitation. These findings also showed that, when similar structures were designed and seismic considerations were warranted, a suitable inside oblique angle to mitigate dynamic effects should be selected only using a comprehensive analysis. At the same time, traveling wave effect analysis indicated that it couldn’t be ignored when calculating the seismic response of long-span steel-box basket-handle arch bridges
Intrinsic triple degeneracy point bounded by nodal surfaces in chiral photonic crystal
In periodic systems, band degeneracies are usually protected and classified
by spatial symmetries. However, the Gamma point at zero-frequency of a photonic
system is an intrinsic degeneracy due to the polarization degree of freedom of
electromagnetic waves. We show here that in chiral photonic crystals, such an
intrinsic degeneracy node carries +(-)2 chiral topological charge and the
topological characters is the same as a spin-1 Weyl point manifested as a
triple degeneracy of two linear propagating bands intersecting a flat band
representing the electrostatic solution. Such an intrinsic triple degeneracy
point (TDP) at Gamma is usually buried in bulk band projections and the
topological charge at photonic zero-frequency has never been observed. Here, by
imposing space-group screw symmetry to the chiral photonic crystal, the
Brillouin zone boundary is transformed into an oppositely charged nodal surface
enclosing the Gamma point. The emergent Fermi-arcs on sample surface are then
forced to connect the bulk band projections of these topological singularities,
revealing the embedded non-trivial topology
Case report and literature review: Acute rhabdomyolysis caused by overheating of electric blanket complicated with Guillain-Barré syndrome
Rhabdomyolysis (RM) induced by electric blankets is exceedingly rare, with only three cases identified in our literature review. Both RM and Guillain–Barré syndrome (GBS) present with similar clinical manifestations of myalgia and muscle weakness, posing a potential challenge for accurate diagnosis in clinical settings. This report presents the case of a 22-year-old man who developed RM subsequent to the use of an electric blanket. Despite undergoing plasma exchange and renal replacement therapy, the patient continued to exhibit poor muscle strength in both lower limbs. Subsequent comprehensive evaluation revealed the presence of concurrent GBS. Following a 5-day course of intravenous gamma globulin treatment, the patient experienced rapid recovery of muscle strength and was discharged. Additionally, we reviewed seven cases from the literature of coexistent RM and GBS. This indicated that investigation of the timing of onset of muscle strength decline in RM patients could help to identify potential concurrent neurological or muscular disorders. In cases in which concurrent GBS and RM cannot be definitively ascertained during early hospitalization, prioritizing plasma exchange treatment may lead to improved patient outcomes
Integrative analysis of different low-light-tolerant cucumber lines in response to low-light stress
IntroductionLow light stress inhibits plant growth due to a line of physiological disruptions in plants, and is one of the major barriers to protected cucumber cultivation in northern China.MethodsTo comprehensively understand the responses of cucumber seedlings to low-light stress, the low-light-tolerant line (M67) and The low-light-sensitive line (M14) were conducted for the analysis of photosynthetic phenotype, RNA sequencing (RNA-seq) and the expression level of photosynthesis-related genes in leaves under low-light stress and normal light condition (control).ResultsThe results showed that there was a sharp decrease in the photosynthate accumulation in the leaves of the sensitive line, M14, resulting in a large decrease in the photosynthetic rate (Pn) (with 31.99%) of leaves compared to that of the control, which may have been caused by damage to chloroplast ultrastructure or a decrease in chlorophyll (Chl) content. However, under the same low-light treatment, there was no large drop in the photosynthate accumulation and even no decrease in Pn and Chl content for the tolerant line, M67. Moreover, results of gene expression analysis showed that the expression level of genes CsPsbQ (the photosystem II oxygen-evolving enhancer protein 3 gene) and Csgamma (ATPase, F1 complex gene) in the M14 leaves decreased sharply (by 35.04% and 30.58%, respectively) compared with the levels in the M67 leaves, which decreased by 14.78% and 23.61%, respectively. The expression levels of genes involved in Chl synthesis and carbohydrate biosynthesis in the leaves of M14 decreased markedly after low-light treatment; in contrast, there were no sharp decreases or changes in leaves of M67.DiscussionOver all, the ability of cucumber to respond to low-light stress, as determined on the basis of the degree of damage in leaf structure and chloroplast ultrastructure, which corresponded to decreased gene expression levels and ATP phosphorylase activity, significantly differed between different low-light-tolerant lines, which was manifested as significant differences in photosynthetic capacity between them. Results of this study will be a reference for comprehensive insight into the physiological mechanism involved in the low-light tolerance of cucumber
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
Dynamic Characteristics and Seismic Response Analysis of a Long-Span Steel-Box Basket-Handle Railway Arch Bridge
The inside oblique angle between the vertical plane and the arch rib has been shown to be one of the main factors influencing dynamic properties of long-span steel-box basket-handle arch bridges. Details related to the extent, that the inside oblique angle influenced the dynamic characteristics and the seismic response of the arch bridge under the combined longitudinal and vertical seismic excitation and under the combined lateral and vertical seismic excitation, were reported herein. Four oblique angles (0°, 3°, 4.8°, and 6°) were selected based on the arch ribs height and bridge deck width. Findings suggested that a larger inside oblique angle increased the structural stiffness and thus the part internal forces when subjected to seismic excitation. These findings also showed that, when similar structures were designed and seismic considerations were warranted, a suitable inside oblique angle to mitigate dynamic effects should be selected only using a comprehensive analysis. At the same time, traveling wave effect analysis indicated that it couldn’t be ignored when calculating the seismic response of long-span steel-box basket-handle arch bridges
Using Web Crawler Technology for Geo-Events Analysis: A Case Study of the Huangyan Island Incident
Social networking and network socialization provide abundant text information and social relationships into our daily lives. Making full use of these data in the big data era is of great significance for us to better understand the changing world and the information-based society. Though politics have been integrally involved in the hyperlinked world issues since the 1990s, the text analysis and data visualization of geo-events faced the bottleneck of traditional manual analysis. Though automatic assembly of different geospatial web and distributed geospatial information systems utilizing service chaining have been explored and built recently, the data mining and information collection are not comprehensive enough because of the sensibility, complexity, relativity, timeliness, and unexpected characteristics of political events. Based on the framework of Heritrix and the analysis of web-based text, word frequency, sentiment tendency, and dissemination path of the Huangyan Island incident were studied by using web crawler technology and the text analysis. The results indicate that tag cloud, frequency map, attitudes pie, individual mention ratios, and dissemination flow graph, based on the crawled information and data processing not only highlight the characteristics of geo-event itself, but also implicate many interesting phenomenon and deep-seated problems behind it, such as related topics, theme vocabularies, subject contents, hot countries, event bodies, opinion leaders, high-frequency vocabularies, information sources, semantic structure, propagation paths, distribution of different attitudes, and regional difference of net citizens’ response in the Huangyan Island incident. Furthermore, the text analysis of network information with the help of focused web crawler is able to express the time-space relationship of crawled information and the information characteristic of semantic network to the geo-events. Therefore, it is a useful tool to collect information for understanding the formation and diffusion of web-based public opinions in political events
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