Cap-shaped skeletal fossils are the earliest undisputed body fossils of mollusks appearing in the basal Cambrian. A study on the morphometry of cap-shaped fossils from the Nanjiang area (North Sichuan, China) is undertaken to understand the origin and evolution of the early mollusks. The distribution of these fossil cap-shaped mollusks indicates a stepwise increase in their diversity during the early Cambrian. Maikhanella Zhegallo in Voronin et al., 1982 co-occuring with the spinose sclerites of siphogonuchitids, is regarded as the earliest scleritized mollusk. It is followed by other maikhanellids, e.g., Purella Missarzhevsky, 1974 and Yunnanopleura Yu, 1987, which co-occur with the earliest univalved helcionellids, e.g., Igorella Missarzhevsky in Rozanov et al., 1969. Cluster analysis of their morphometric characteristics shows that the Maikhanella group is similar to the Purella and Yunnanopleura groups, but is less comparable with univalved helcionellids. The maikhanellids are interpreted as representatives of the stem group Aculifera, although it remains uncertain if one or two larger cap-shaped shell plates were present on the elongate slug-like body, comparable to those of Halkieria Poulsen, 1967 or Orthrozanclus Conway Morris and Caron, 2007. Maikhanellids are characterized by the prominent protrusions or scales on the cap-shaped shell plates arranged in a concentric pattern around the shell apex. Evolutionarily, the protrusions or scales are reduced in younger strata, whereas subsequently a typically concentric ornament developed, the cap-shaped shell plates developed higher profiles, and the apical region became increasingly bare of scales. Meanwhile, the cap-shaped shell plates gradually evolved into a helcionellid-like appearance with an anteroposteriorly inclined apex. The morphological evolution of the earliest sclerotized mollusks reflects biotic evolution and environmental adaption among the stem-group mollusks during the early Cambrian.

This study is performed to figure out how the presence of diabetes affects the infection, progression and prognosis of 2019 novel coronavirus disease (COVID-19), and the effective therapy that can treat the diabetes-complicated patients with COVID-19. A multicentre study was performed in four hospitals. COVID-19 patients with diabetes mellitus (DM) or hyperglycaemia were compared with those without these conditions and matched by propensity score matching for their clinical progress and outcome. Totally, 2444 confirmed COVID-19 patients were recruited, from whom 336 had DM. Compared to 1344 non-DM patients with age and sex matched, DM-COVID-19 patients had significantly higher rates of intensive care unit entrance (12.43% vs. 6.58%, P = 0.014), kidney failure (9.20% vs. 4.05%, P = 0.027) and mortality (25.00% vs. 18.15%, P < 0.001). Age and sex-stratified comparison revealed increased susceptibility to COVID-19 only from females with DM. For either non-DM or DM group, hyperglycaemia was associated with adverse outcomes, featured by higher rates of severe pneumonia and mortality, in comparison with non-hyperglycaemia. This was accompanied by significantly altered laboratory indicators including lymphocyte and neutrophil percentage, C-reactive protein and urea nitrogen level, all with correlation coefficients >0.35. Both diabetes and hyperglycaemia were independently associated with adverse prognosis of COVID-19, with hazard ratios of 10.41 and 3.58, respectively.

Nicotine 2,6-dihydroxybenzoate is a nicotine salt that can be used as the nicotine source in tobacco products. X-ray powder diffraction data, unit-cell parameters, and space group for nicotine 2,6-dihydroxybenzoate, C10H15N2⋅C7H5O4, are reported [a = 7.726(8) Å, b = 11.724(3) Å, c = 9.437(1) Å, α = 90°, β = 109.081(3)°, γ = 90°, unit-cell volume V = 802.902 Å3, Z = 2, ρcal = 1.309 g cm−3, and space group P21] at room temperature. All measured lines were indexed and were consistent with the P21 space group.

Bathymetric simultaneous localisation and mapping (SLAM) methods yield accurate navigation results for autonomous underwater vehicles (AUVs) and can construct consistent seabed terrain maps. Multiple independently working vehicles can complete tasks like surveying and mapping efficiently, which means cooperative bathymetric SLAM using multiple AUVs is suitable for large-scale seabed mapping. However, the transmission of bathymetric measurements collected using a multi-beam echo sounder over a low bandwidth, noisy, and unreliable acoustic channel is difficult, making cooperative bathymetric SLAM very challenging. This paper develops a graph-based cooperative bathymetric SLAM system that can compress many bathymetric measurements into small-scale acoustic packets and yield accurate navigation results with a 10% loss of acoustic packets caused by unreliable acoustic communication. According to the simulation conducted using the field data, the new algorithm is shown to be robust and capable of providing accurate location and mapping results over a low bandwidth, noisy, and unreliable acoustic channel.

This study examined the influences of coated folic acid (CFA) and coated riboflavin (CRF) on bull performance, nutrients digestion and ruminal fermentation. Forty-eight Angus bulls based on a randomised block and 2 × 2 factorial design were assigned to four treatments. The CFA of 0 or 6 mg of folic acid/kg DM was supplemented in diets with CRF 0 or 60 mg riboflavin (RF)/kg DM. Supplementation of CRF in diets with CFA had greater increase in daily weight gain and feed efficiency than in diets without CFA. Supplementation with CFA or CRF enhanced digestibility of DM, organic matter, crude protein, neutral-detergent fibre and non-fibre carbohydrate. Ruminal pH and ammonia N content decreased and total volatile fatty acids concentration and acetate to propionate ratio elevated for CFA or CRF addition. Supplement of CFA or CRF increased the activities of fibrolytic enzymes and the numbers of total bacteria, protozoa, fungi, dominant fibrolytic bacteria and Prevotella ruminicola. The activities of α-amylase, protease and pectinase and the numbers of Butyrivibrio fibrisolvens and Ruminobacter amylophilus were increased by CFA but were unaffected by CRF. Blood concentration of folate elevated and homocysteine decreased for CFA addition. The CRF supplementation elevated blood concentrations of folate and RF. These findings suggested that CFA or CRF inclusion had facilitating effects on performance and ruminal fermentation, and combined addition of CFA and CRF had greater increase in performance than CFA or CRF addition alone in bulls.

The wheat aphid Sitobion miscanthi (CWA) is an important harmful pest in wheat fields. Insecticide application is the main method to effectively control wheat aphids. However, CWA has developed resistance to some insecticides due to its extensive application, and understanding resistance mechanisms is crucial for the management of CWA. In our study, a new P450 gene, CYP4CJ6, was identified from CWA and showed a positive response to imidacloprid and thiamethoxam. Transcription of CYP4CJ6 was significantly induced by both imidacloprid and thiamethoxam, and overexpression of CYP4CJ6 in the imidacloprid-resistant strain was also observed. The sensitivity of CWA to these two insecticides was increased after the knockdown of CYP4CJ6. These results indicated that CYP4CJ6 could be associated with CWA resistance to imidacloprid and thiamethoxam. Subsequently, the posttranscriptional regulatory mechanism was assessed, and miR-316 was confirmed to participate in the posttranscriptional regulation of CYP4CJ6. These results are crucial for clarifying the roles of P450 in the resistance of CWA to insecticides.

The orogenic process and crustal growth of the Changning–Menglian Palaeo-Tethys orogenic belt in the southeastern Tibetan Plateau is not fully understood. Triassic Caojian rhyolites and granites occur extensively in this orogenic belt and represent important constraints for this issue. This study aims to examine the relationships between the Triassic Caojian rhyolites and granites and to gain a better understanding of their possible petrogenesis. The study used zircon U–Pb geochronology, trace element analyses and Sr–Nd–Hf isotope data to better understand the relationships and possible origin of the rhyolites and granites. Recent zircon U–Pb ages indicated that the Caojian rhyolites were emplaced at 227.2 Ma, whereas age estimates for Caojian granites were slightly older (233.4–236.9 Ma). The Caojian rhyolites are enriched in large-ion lithophile elements and high-field-strength elements, with elevated FeOtot/MgO and Ga/Al ratios. However, they are significantly depleted in Ba, Sr, Eu, P and Ti. These geochemical characteristics indicate that they have an A-type affinity. Furthermore, the Caojian granites comprise biotite monzogranites and granodiorites and show unfractionated composition. Mineralogically, the Caojian granites were found to contain diagnostic I-type minerals such as hornblende. Geochemical data suggest that the petrogenesis of the Triassic Caojian rhyolites is characterized by rejuvenation of crystal mush represented by the Triassic Caojian granites. The necessary thermal input was supplied by mafic magma. This magmatic evolution was likely related to lithospheric delamination and upwelling of the asthenosphere during the Mid- to Late Triassic, forming post-collisional I-type granites and A-type volcanics in the Changning–Menglian Palaeo-Tethys orogenic belt.

Thermal convection of fluid is a more efficient way than diffusion to carry heat from hot sources to cold places. Here, we experimentally study the Rayleigh–Bénard convection of aqueous glycerol solution in a cubic cell with suspensions of rod-like particles made of polydimethylsiloxane. The particles are inertial due to their large thermal expansion coefficient and finite sizes. The thermal expansion coefficient of the particles is three times larger than that of the background fluid. This contrast makes the suspended particles lighter than the local fluid in hot regions and heavier in cold regions. The heat transport is enhanced at relatively large Rayleigh number ($\textit {Ra}$) but reduced at small $\textit {Ra}$. We demonstrate that the increase of Nusselt number arises from the particle–boundary layer interactions: the particles act as ‘active’ mixers of the flow and temperature fields across the boundary layers.

We propose a novel Fabry–Pérot (FP) antenna consisting of a checkered polarization-conversion metasurface (PCM), corner-cut square patch antennas, and sandwiched compounds. The proposed antenna achieves low radar-cross-section (RCS), high gain, and wideband circular polarization (CP). The corner-cut square patch antennas facilitate high reflectivity, satisfactory transmission magnitude, and the desired phase difference. An embedded metal between two rings of substrate contributes to reducing cross-polarization, improving transmission efficiency, enhancing bandwidth, and reducing RCS. Following simulations, we fabricated a prototype of the proposed antenna and tested its performance. Measurements from the simulation and prototype tests were similar within a reasonable margin of error. Compared with alternative antennas, our proposed FP antenna offers high gain, wideband CP, low cost, a low RCS, and a lower profile.

To investigate the influences of cobalt (Co) and folic acid (FA) on growth performance and rumen fermentation, Holstein male calves (n 40) were randomly assigned to four groups according to their body weights. Cobalt sulphate at 0 or 0·11 mg Co/kg DM and FA at 0 or 7·2 mg/kg DM were used in a 2 × 2 factorial design. Average daily gain was elevated with FA or Co supplementation, but the elevation was greater for supplementing Co in diets without FA than with FA. Supplementing FA or Co increased DM intake and total-tract nutrient digestibility. Rumen pH was unaltered with FA but reduced with Co supplementation. Concentration of rumen total volatile fatty acids was elevated with FA or Co inclusion. Acetate percentage and acetate to propionate ratio were elevated with FA inclusion. Supplementing Co decreased acetate percentage and increased propionate percentage. Activities of xylanase and α-amylase and populations of total bacteria, fungi, protozoa, Ruminococcus albus, Fibrobacter succinogenes and Prevotella ruminicola increased with FA or Co inclusion. Activities of carboxymethyl-cellulase and pectinase increased with FA inclusion and population of methanogens decreased with Co addition. Blood folates increased and homocysteine decreased with FA inclusion. Blood glucose and vitamin B12 increased with Co addition. The data suggested that supplementing 0·11 mg Co/kg DM in diets containing 0·09 mg Co/kg DM increased growth performance and nutrient digestibility but had no improvement on the effects of FA addition in calves.

Smooth-walled open channel flow datasets, covering both the direct numerical simulation and experimental measurements with a friction Reynolds number ${\textit {Re}}_\tau$ at a low-to-moderate level of $550\sim 2400$, are adopted to investigate the contributions of different scale motions to the mean wall-shear stress in open channel flows (OCFs). The FIK identity decomposition method by Fukagata et al. (Phys. Fluids, vol. 14, 2002, L73) combined with a scale decomposition is chosen for this research. To see whether/how the contributions in OCFs differ with those in closed channel flows (CCFs), comparisons between the two flows are also made. The scale-decomposed ‘turbulent’ contribution results of present OCFs exhibit two dominant contribution modes (i.e. large-scale motions (LSMs) and very-large-scale motions (VLSMs)) at a streamwise wavelength $\lambda _x=1\sim 2h$ and $O(10h)$, where $h$ is the water depth. The large scales with $\lambda _x>3h$ and $\lambda _x>10h$ are demonstrated to contribute to over 40 % and 20 % of the mean wall-shear stress, respectively. Compared with CCFs, slightly higher and lower contributions in the $\lambda _x>O(10h)$ and $\lambda _x < O(10h)$ wavelength ranges are observed in OCFs, revealing the important free-surface effects in OCFs. Possible mechanisms are discussed to lend support for the observed differences between the two flows.

The geometry of compound sessile drops at equilibrium on a flat substrate can exhibit a variety of complicated morphological configurations. In this paper, we first investigate the configuration boundaries of the compound sessile drops in a wide parameter space, where a specific configuration is not stable outside its boundaries. Then, we focus on the transitions among the axisymmetric configurations, i.e. encapsulation, lens and collars. The configuration transitions result from the variation of the wettability of the substrate and the volume ratio of the two component droplets. With the help of theoretical analysis and numerical simulations, we obtain previously unidentified criteria for the onset of configuration transition, identify the irreversible and reversible configuration transitions, reveal the dynamic behaviours of configuration transitions that are not accessible to theoretical analysis, and provide a further step towards the ultimate purpose of such work, which is the controllable reconfiguration of the compound sessile drops.

To assess the relationship between the neutrophil-to-lymphocyte ratio (NLR) and related parameters to the severity of coronavirus disease 2019 (COVID-19) symptoms. Clinical data from 38 COVID-19 patients who were diagnosed, treated and discharged from the Qishan Hospital in Yantai over the period from January to February 2020 were analysed. NLR and procalcitonin (PCT) were determined in the first and fourth weeks after their admission, along with the clinical characteristics and laboratory test results of these patients. Based on results as obtained on the first and fourth weeks after admission, five indices consisting of NLR, white blood cells, neutrophils, lymphocytes (LY) and monocytes (MON) were selected to generate receiver operating characteristic curves, while optimal cutoff values, sensitivities and specificities were obtained according to the Yuden index. Statistically significant differences in neutrophils, LY and the NLR were present in the severe vs. moderate COVID-19 group from the first to the fourth week of their hospitalisation. The cut-off value of NLR for predicting the severity of COVID-19 was 4.425, with a sensitivity of 0.855 and a specificity of 0.979. A statistically significant positive correlation was present between PCT and NLR in the severe group as determined within the first week of admission. NLR can serve as a predictor of COVID-19 disease severity as patients' progress from the first to the fourth week of their hospitalisation. The statistically significant positive correlation between levels of NLR and PCT in severe patients indicated that increases in NLR were accompanied with gradual increases in PCT.

Hexangulaconulariids (Cambrian stages 1–2) are an extinct group of medusozoan polyps having a biradially symmetrical, fan-shaped periderm that is distinct from those of medusozoan polyps showing three-, four-, five-, or six-fold radial symmetry. Hexangulaconulariids exhibit substantial variation in gross morphology, including variation in the number of faces on each of the two major sides of the periderm. An intermediate taxon of hexangulaconulariids with ten faces (five on each major side) was expected. Here we describe a new hexangulaconulariid, Decimoconularia isofacialis new genus new species from Bed 5 of the Yanjiahe Formation (Cambrian Stage 2) in the Three Gorges area of Hubei Province, China. The new taxon differs from other hexangulaconulariids (Arthrochites, Hexaconularia, and Septuconularia) mainly in possessing a total of ten faces. The two lateral margins are each marked by a ridge in about the apertural half of the periderm and by a collinear furrow in about the apical half, while the five faces on each major side are bounded by a furrow in about the apertural half and by a collinear ridge in about the apical half. Among hexangulaconulariids, Decimoconularia and Septuconularia may be more closely related to each other than either genus is to Arthrochites or Hexaconularia.

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