91 research outputs found
Funding Liquidity Shocks in a Quasi-Experiment: Evidence from the CDS Big Bang
A major change in trading conventions in April 2009, the so-called “CDS Big Bang,” induces upfront fees for trading North American CDSs. Exploiting this quasi-experiment, we provide evidence that upfront fees have a differential effect on CDS bid-ask spreads across CDS premiums. Furthermore, the funding effect is stronger for CDS contracts on smaller and riskier firms, contracts with longer maturities, and non-centrally-cleared contracts. The effect also becomes stronger after Deutsche Bank exits the CDS market. Finally, we find similar results using European CDSs. Our experimental setting offers new economic insights on the quantification and mechanism of the funding liquidity effect
Energy-resolved Photoconductivity Mapping in a Monolayer-bilayer WSe2 Lateral Heterostructure
Vertical and lateral heterostructures of van der Waals materials provide
tremendous flexibility for band structure engineering. Since electronic bands
are sensitively affected by defects, strain, and interlayer coupling, the edge
and heterojunction of these two-dimensional (2D) systems may exhibit novel
physical properties, which can be fully revealed only by spatially resolved
probes. Here, we report the spatial mapping of photoconductivity in a
monolayer-bilayer WSe2 lateral heterostructure under multiple excitation
lasers. As the photon energy increases, the light-induced conductivity detected
by microwave impedance microscopy first appears along the hetero-interface and
bilayer edge, then along the monolayer edge, inside the bilayer area, and
finally in the interior of the monolayer region. The sequential emergence of
mobile carriers in different sections of the sample is consistent with the
theoretical calculation of local energy gaps. Quantitative analysis of the
microscopy and transport data also reveals the linear dependence of
photoconductivity on the laser intensity and the influence of interlayer
coupling on carrier recombination. Combining theoretical modeling, atomic scale
imaging, mesoscale impedance microscopy, and device-level characterization, our
work suggests an exciting perspective to control the intrinsic band-gap
variation in 2D heterostructures down to the few-nanometer regime.Comment: 18 pages, 5 figures; Nano Lett., Just Accepted Manuscrip
Formamide deionized accelerates the somatic embryogenesis of Cunninghamia lanceolata
Aim of the study: To improve the efficiency of the somatic embryogenesis (SE) in Cunninghamia lanceolata.
Area of the study: The study was conducted at Nanjing Forestry University (Nanjing, China).
Material and methods: Immature cones of C. lanceolata, genotype 01A1 which was planted in Yangkou State-owned Forest Farm (Fujian, China), were used to induced callus. These calli were used to induce SE, concentration gradients of 0 g/L, 0.01134 g/L, 0.1134 g/L, 1.1134 g/L and 11.34 g/L of FD was added, to explore the optimal concentration for promoting SE of C. lanceolata.
Main results: Low concentration of FD promoted the maturation of somatic embryos, while high concentration of FD lead to browning of embryogenic callus. The seedling rate and rooting number of seedlings induced by different concentrations of FD were significantly different.
Research highlights: This study may aid in the rapid maturation of C. lanceolata somatic embryos and is useful for accelerated C. lanceolata breeding.
Keywords: C. lanceolata; Formamide Deionized; Somatic embryogenesis; Seedling rate.
Abbreviations used: FD (Formamide Deionized), FD0 (the concentration of 0 g/L FD), FD0.01134 (the concentration of 0.01134 g/L FD), FD0.1134 (the concentration of 0.1134 g/L FD), FD1.134 (the concentration of 1.134 g/L FD), FD11.34 (the concentration of 11.34 g/L FD)
Genome-wide analysis of the GRAS gene family in Liriodendron chinense reveals the putative function in abiotic stress and plant development
IntroductionGRAS genes encode plant-specific transcription factors that play essential roles in plant growth and development. However, the members and the function of the GRAS gene family have not been reported in Liriodendron chinense. L. chinense, a tree species in the Magnolia family that produces excellent timber for daily life and industry. In addition, it is a good relict species for plant evolution research.MethodsTherefore, we conducted a genome-wide study of the LcGRAS gene family and identified 49 LcGRAS genes in L. chinense.ResultsWe found that LcGRAS could be divided into 13 sub-groups, among which there is a unique branch named HAM-t. We carried out RNA sequencing analysis of the somatic embryos from L. chinense and found that LcGRAS genes are mainly expressed after heart-stage embryo development, suggesting that LcGRAS may have a function during somatic embryogenesis. We also investigated whether GRAS genes are responsive to stress by carrying out RNA sequencing (RNA-seq) analysis, and we found that the genes in the PAT subfamily were activated upon stress treatment, suggesting that these genes may help plants survive stressful environments. We found that PIF was downregulated and COR was upregulated after the transient overexpression of PATs, suggesting that PAT may be upstream regulators of cold stress. DiscussionCollectively, LcGRAS genes are conserved and play essential roles in plant development and adaptation to abiotic stress
WaterScenes: A Multi-Task 4D Radar-Camera Fusion Dataset and Benchmark for Autonomous Driving on Water Surfaces
Autonomous driving on water surfaces plays an essential role in executing
hazardous and time-consuming missions, such as maritime surveillance, survivors
rescue, environmental monitoring, hydrography mapping and waste cleaning. This
work presents WaterScenes, the first multi-task 4D radar-camera fusion dataset
for autonomous driving on water surfaces. Equipped with a 4D radar and a
monocular camera, our Unmanned Surface Vehicle (USV) proffers all-weather
solutions for discerning object-related information, including color, shape,
texture, range, velocity, azimuth, and elevation. Focusing on typical static
and dynamic objects on water surfaces, we label the camera images and radar
point clouds at pixel-level and point-level, respectively. In addition to basic
perception tasks, such as object detection, instance segmentation and semantic
segmentation, we also provide annotations for free-space segmentation and
waterline segmentation. Leveraging the multi-task and multi-modal data, we
conduct numerous experiments on the single modality of radar and camera, as
well as the fused modalities. Results demonstrate that 4D radar-camera fusion
can considerably enhance the robustness of perception on water surfaces,
especially in adverse lighting and weather conditions. WaterScenes dataset is
public on https://waterscenes.github.io
Out-of-Plane Piezoelectricity and Ferroelectricity in Layered α-In2Se3 Nanoflakes
Piezoelectric and ferroelectric properties in the two-dimensional (2D) limit are highly desired for nanoelectronic, electromechanical, and optoelectronic applications. Here we report the first experimental evidence of out-of-plane piezoelectricity and ferroelectricity in van der Waals layered α-In2Se3 nanoflakes. The noncentrosymmetric R3m symmetry of the α-In2Se3 samples is confirmed by scanning transmission electron microscopy, second-harmonic generation, and Raman spectroscopy measurements. Domains with opposite polarizations are visualized by piezo-response force microscopy. Single-point poling experiments suggest that the polarization is potentially switchable for α-In2Se3 nanoflakes with thicknesses down to ∼10 nm. The piezotronic effect is demonstrated in two-terminal devices, where the Schottky barrier can be modulated by the strain-induced piezopotential. Our work on polar α-In2Se3, one of the model 2D piezoelectrics and ferroelectrics with simple crystal structures, shows its great potential in electronic and photonic applications
Halophyte Nitraria billardieri CIPK25 promotes photosynthesis in Arabidopsis under salt stress
The calcineurin B-like (CBL)-interacting protein kinases (CIPKs), a type of plant-specific genes in the calcium signaling pathway, function in response to adverse environments. However, few halophyte derived CIPKs have been studied for their role in plant physiological and developmental adaptation during abiotic stresses, which inhibits the potential application of these genes to improve environmental adaptability of glycophytes. In this study, we constructed Nitraria billardieri CIPK25 overexpressing Arabidopsis and analyzed the seedling development under salt treatment. Our results show that Arabidopsis with NbCIPK25 expression exhibits more vigorous growth than wild type plants under salt condition. To gain insight into the molecular mechanisms underlying salt tolerance, we profiled the transcriptome of WT and transgenic plants via RNA-seq. GO and KEGG analyses revealed that upregulated genes in NbCIPK25 overexpressing seedlings under salt stress are enriched in photosynthesis related terms; Calvin-cycle genes including glyceraldehyde-3-phosphate dehydrogenases (GAPDHs) are significantly upregulated in transgenic plants, which is consistent with a decreased level of NADPH (GAPDH substrate) and increased level of NADP+. Accordingly, NbCIPK25 overexpressing plants exhibited more efficient photosynthesis; soluble sugar and proteins, as photosynthesis products, showed a higher accumulation in transgenic plants. These results provide molecular insight into how NbCIPK25 promotes the expression of genes involved in photosynthesis, thereby maintaining plant growth under salt stress. Our finding supports the potential application of halophyte-derived NbCIPK25 in genetic modification for better salt adaptation
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