Diel and Circadian Patterns of Locomotor Activity in the Adults of Diamondback Moth (Plutella xylostella)

The Diamondback Moth (Plutella xylostella) is a highly destructive lepidopteran pest of cruciferous crops. However, there still is relatively little known about the locomotor activities of diel and the circadian patterns in P. xylostella. Here, we present an analysis of the diel locomotion of P. xylostella under several laboratory settings. We established a system for measuring the individual locomotor activities of P. xylostella and found that both males and females showed a nocturnal pattern of activity under 26 or 20 °C LD conditions, with activity peaking immediately after lights off and quickly declining after lights on. In addition, we showed that it is difficult to assess the free-running circadian rhythms of P. xylostella under 26 °C DD conditions. However, we found that males showed a higher power, rhythm index (RI) and rhythmic ratio than females under 20 °C DD conditions, which indicated that males in low-temperature conditions are much more suitable to study the free-running circadian rhythms of P. xylostella. The findings of this study will help us to have a better understanding of the diel activity of P. xylostella and may provide a foundation for the development of an effective pest management strategy

Evaluation of ScCO2-water performance on bituminous coal : insights from experiments and 3D CT image reconstruction

Evaluating the coupling of moisture content with supercritical CO2 (ScCO2) in coal is important for CO2 geological sequestration and enhanced coalbed methane recovery. Changes of minerals and microstructure in bituminous coal after ScCO2-water treatment were explored employing X-ray powder diffraction and micro-computed tomography (CT), and the seepage behavior evolution was further investigated by performing computational fluid dynamic analysis after 3D CT reconstruction. The results show that carbonate minerals dissolved remarkably after ScCO2-water treatment, but a reversible chemical reaction occurred in calcite minerals. The induced mineral dissolution, pore-fracture formation and expansion changed the pore-fracture structure in coal significantly. As a result, the amount and diameter of pores and throats obviously increased as the total volume and surface area of the pore-fracture increased to be nearly twice of the original coal. Additionally, the pore-fracture connectivity improved from 44.7 to 67.6% with a coordination number greater than 3 after ScCO2-water treatment. Pores of the equivalent radius of 75 μm were also found to contribute most to the permeability, rather than pores of the largest equivalent radius, as reported previously, indicating both the size and volume proportion of pores should be considered in permeability evaluation. Numerical modeling reveals that pore pressure decays faster along flow pathways after ScCO2-water treatment due to pore-fracture volume enhancement. The ScCO2-water treatment not only increased seepage channels in coal but also intensified the preferential flow. Along with the pore-fracture volume enhancement, the permeability heterogeneity in coal decreased after the ScCO2-water treatment, but the permeability enhancement along different directions varied

Enhancing the Sealing Performance of Bolted Ball Joints by Gaskets: Numerical Simulation and Experiment

With the increasing utilization of bolted ball joint steel mesh structures in offshore floating platforms and deep-sea fish cages, the issue of seawater infiltrating the joints and members through the installation gaps of the bolted ball joint, leading to subsequent corrosion, has become increasingly prominent. This article presents an innovative method to improve the sealing performance of bolted ball joints. The approach involves creating sealed surfaces within the contact gaps between the sleeve and connecting components by adding circular grooves and sealing washers to both ends of the sleeve. Subsequently, a two-dimensional finite element analysis model of the bolted ball joint with the sealing structure was created using SOLIDWORKS 2021 and ANSYS Workbench 2022 R1. The study analyzes the sealing gasket’s contact pressure at various compression levels and evaluates its performance with bubble tests for air tightness. Research results show a linear relationship between the contact pressure and compression rate, achieving sealing pressures of 2.91 MPa, 4.22 MPa, and 5.95 MPa at compression levels of 8%, 11%, and 14%, respectively. Experimental testing demonstrates that the improved bolted ball joint exhibits excellent sealing performance

Influence of redox conditions on animal distribution and soft-bodied fossil preservation of the Lower Cambrian Chengjiang Biota

The exceptionally preserved Chengjiang Biota (Yunnan, China) is significant for understanding the rapid development of complex animal-rich ecosystems during the evolutionary radiation of the Cambrian. However, the ecological signal provided by the fossils captured in this deposit may not reflect accurately the in-life community, with transport and decay of carcasses being the principal processes responsible for potential modification. The principal fossil-bearing interval (Maotianshan Shale Member, Yu'anshan Formation) is comprised of claystones of two distinct depositional origins: the “background” beds represent slow hemipelagic deposition into deep waters, while the “event” beds represent distal turbidites or storm-generated beds. Each bed type has a distinct fossil assemblage and preservation mode underscoring the importance of interpreting the palaeoenvironment of each bed type. Here, we interpret palaeo-redox conditions for both the background beds and the event beds by conducting a systematic geochemical study using iron speciation, δ34Spy, δ13Ccarbδ13CTOCand molybdenum abundance. These data are from the most complete core recovered from the Chengjiang fossiliferous units and allow us to distinguish redox conditions where the animals lived, and where they were buried and exceptionally preserved. Our results demonstrate that background beds were dominated by dysoxic conditions; here, a diverse sponge community tolerant of low-oxygen conditions lived. In contrast, the shallower shelf and offshore-transitional environments, where event beds were sourced, were almost persistently oxic, and it was here where the diverse Chengjiang Biota flourished. Thus, the Chengjiang sediments record two distinct palaeocommunities within the background and the event beds. The contrasting redox conditions in close spatial proximity likely facilitated the soft-bodied fossil preservation. Our findings provide a valuable case study in the necessity to understand ecological composition and exceptional preservation informed by environmental context

Are medical record front page data suitable for risk adjustment in hospital performance measurement? Development and validation of a risk model of in-hospital mortality after acute myocardial infarction

Objectives To develop a model of in-hospital mortality using medical record front page (MRFP) data and assess its validity in case-mix standardisation by comparison with a model developed using the complete medical record data.Design A nationally representative retrospective study.Setting Representative hospitals in China, covering 161 hospitals in modelling cohort and 156 hospitals in validation cohort.Participants Representative patients admitted for acute myocardial infarction. 8370 patients in modelling cohort and 9704 patients in validation cohort.Primary outcome measures In-hospital mortality, which was defined explicitly as death that occurred during hospitalisation, and the hospital-level risk standardised mortality rate (RSMR).Results A total of 14 variables were included in the model predicting in-hospital mortality based on MRFP data, with the area under receiver operating characteristic curve of 0.78 among modelling cohort and 0.79 among validation cohort. The median of absolute difference between the hospital RSMR predicted by hierarchical generalised linear models established based on MRFP data and complete medical record data, which was built as ‘reference model’, was 0.08% (10th and 90th percentiles: −1.8% and 1.6%). In the regression model comparing the RSMR between two models, the slope and intercept of the regression equation is 0.90 and 0.007 in modelling cohort, while 0.85 and 0.010 in validation cohort, which indicated that the evaluation capability from two models were very similar.Conclusions The models based on MRFP data showed good discrimination and calibration capability, as well as similar risk prediction effect in comparison with the model based on complete medical record data, which proved that MRFP data could be suitable for risk adjustment in hospital performance measurement