In this paper, instabilities in the flow over a circular cylinder of diameter $D$ with dual splitter plates attached to its rear surface are numerically investigated using the spectral element method. The key parameters are the splitter plate length $L$ , the attachment angle $\unicode[STIX]{x1D6FC}$ and the Reynolds number $Re$ . The presence of the plates was found to significantly modify the flow topology, leading to substantial changes in both the primary and secondary instabilities. The results showed that the three instability modes present in the bare circular cylinder wake still exist in the wake of the present configurations and that, in general, the occurrences of modes A and B are delayed, while the onset of mode QP is earlier in the presence of the splitter plates. Furthermore, two new synchronous modes, referred to as mode A $^{\prime }$ and mode B $^{\prime }$ , are found to develop in the wake. Mode A $^{\prime }$ is similar to mode A but with a quite long critical wavelength. Mode B $^{\prime }$ shares the same spatio-temporal symmetries as mode B but has a distinct spatial structure. With the exception of the case of $L/D=0.25$ , mode A $^{\prime }$ persists for all configurations investigated here and always precedes the transition through mode A. The onset of mode B $^{\prime }$ occurs for $\unicode[STIX]{x1D6FC}>20^{\circ }$ with $L/D=1.0$ and for $L/D>0.5$ with $\unicode[STIX]{x1D6FC}=60^{\circ }$ . The characteristics of all the transition modes are analysed, and their similarities and differences are discussed in detail in comparison with the existing modes. In addition, the physical mechanism responsible for the instability mode B $^{\prime }$ is proposed. The weakly nonlinear feature of mode B $^{\prime }$ , as well as that of mode A $^{\prime }$ , is assessed by employing the Landau model. Finally, selected three-dimensional simulations are performed to confirm the existence of these two new modes and to investigate the nonlinear evolution of the three-dimensional modes.

Existing data on folate status and hepatocellular carcinoma (HCC) prognosis are scarce. We prospectively examined whether serum folate concentrations at diagnosis were associated with liver cancer-specific survival (LCSS) and overall survival (OS) among 982 patients with newly diagnosed, previously untreated HCC, who were enrolled in the Guangdong Liver Cancer Cohort (GLCC) study between September 2013 and February 2017. Serum folate concentrations were measured using chemiluminescent microparticle immunoassay. Cox proportional hazards models were performed to estimate hazard ratios (HR) and 95 % CI by sex-specific quartile of serum folate. Compared with patients in the third quartile of serum folate, patients in the lowest quartile had significantly inferior LCSS (HR = 1·48; 95 % CI 1·05, 2·09) and OS (HR = 1·43; 95 % CI 1·03, 1·99) after adjustment for non-clinical and clinical prognostic factors. The associations were not significantly modified by sex, age at diagnosis, alcohol drinking status and Barcelona Clinic Liver Cancer (BCLC) stage. However, there were statistically significant interactions on both multiplicative and additive scale between serum folate and C-reactive protein (CRP) levels or smoking status and the associations of lower serum folate with worse LCSS and OS were only evident among patients with CRP > 3·0 mg/l or current smokers. An inverse association with LCSS were also observed among patients with liver damage score ≥3. These results suggest that lower serum folate concentrations at diagnosis are independently associated with worse HCC survival, most prominently among patients with systemic inflammation and current smokers. A future trial of folate supplementation seems to be promising in HCC patients with lower folate status.

Isolated gametes can be used to investigate fertilization mechanisms, and probe distant hybridization between different species. Pollen grains of wheat and Setaria viridis are tricellular, containing sperm cells at anthesis. Sperm from these plants were isolated by breaking open pollen grains in a osmotic solution. Wheat ovules were digested in an enzyme solution for 20 min, and then transferred to an isolation solution without enzymes to separate egg cells from ovules. The fusion of wheat egg cells with wheat and S. viridis sperm was conducted using an electro-fusion apparatus. Under suitable osmotic pressure (10% mannitol), calcium concentration of 0.001% (CaCl2·2H2O), and a 30–35 V alternating electric field for 15 s, egg cells and sperm adhered to each other and became arranged in a line. Electroporation of the plasma membrane of egg cells and sperm using a 300–500 V direct-current electric field (45 µs amplitude pulse) caused them to fuse.

Paediatric Mycoplasma pneumoniae pneumonia (MPP) is a major cause of community-acquired pneumonia in China. Data on epidemiology of paediatric MPP from China are little known. This study retrospectively collected data from June 2006 to June 2016 in Beijing Children's Hospital, Capital Medical University of North China and aims to explore the epidemiological features of paediatric MPP and severe MPP (SMPP) in North China during the past 10 years. A total of 27 498 paediatric patients with pneumonia were enrolled. Among them, 37.5% of paediatric patients had MPP. In this area, an epidemic took place every 2–3 years at the peak, and the positive rate of MPP increased during these peak years over time. The peak age of MPP was between the ages of 6 and 10 years, accounting for 75.2%, significantly more compared with other age groups (χ2 = 1384.1, P < 0.0001). The epidemics peaked in September, October and November (χ2 = 904.9, P < 0.0001). Additionally, 13.0% of MPP paediatric patients were SMPP, but over time, the rate of SMPP increased, reaching 42.6% in 2016. The mean age of paediatric patients with SMPP (6.7 ± 3.0 years old) was younger than that of patients with non-SMPP (7.4 ± 3.2 years old) (t = 3.60, P = 0.0001). The prevalence of MPP and SMPP is common in China, especially in children from 6 to 10 years old. Paediatric patients with SMPP tend to be younger than those with non-SMPP. MPP outbreaks occur every 2–3 years in North China. September, October and November are the peak months, unlike in South China. Understanding the epidemiological characteristics of paediatric MPP can contribute to timely treatment and diagnosis, and may improve the prognosis of children with SMPP.

A layer of silver nanoparticles created by thermal annealing of evaporated silver films can increase the photocurrents in silicon-on-insulator (SOI) devices by fivefold or more, but significant enhancements have been restricted to wavelengths greater than 800 nm. Here we report a significant enhancement of photoconductance at shorter wavelengths (500-750 nm) by using a monolayer of silver nanoparticles transferred from a colloidal suspension. Photocurrents on SOI increased in the 500-750 nm spectral range with the addition of silver nanoparticles, with enhancements more than two times; enhancements at longer wavelengths were small, in contrast to results with annealed silver films. We prepared similar colloidal silver nanoparticle monolayers layers on nanocrystalline silicon solar cells with conducting oxide top layers. There is an overall decrease in the quantum efficiency of these cells with the deposition of silver nanoparticles. We attribute these effects to the substantial substrate-mediated changes in the localized surface plasmon resonance frequencies of the differing nanoparticle configurations.

This study aimed to reveal the associated risk factors for latent tuberculosis infection (LTBI) detected by T-SPOT.TB assay among health care workers (HCWs) at different working locations or job categories in China. This cross-sectional study included 934 HCWs who underwent the T-SPOT.TB assay. Demographic and social characteristics of the participants, including age, sex, job categories, department/ward and duration of healthcare service, were recorded. Among 934 HCWs, 267 (28.5867%) were diagnosed as having LTBI with positive T-SPOT.TB assay. HCWs working in inpatient tuberculosis (TB) (odds ratio (OR) 2.917; 95% confidence interval (CI) 1.852–4.596; P < 0.001) and respiratory wards (OR 1.840; 95% CI 1.124–3.011; P = 0.015), and with longer duration of healthcare service (OR 1.048; 95% CI 1.016–1.080; P = 0.003) were risk factors for positive T-SPOT.TB result. Furthermore, longer working duration increased the positive rate of T-SPOT.TB results for physicians and nurses, and physicians had higher risks than nurses for the same working duration. Inpatient TB and respiratory wards were high-risk working locations for HCWs with LTBI, and longer duration of healthcare service also increased the risk of LTBI among HCWs. A complete strategy for TB infection control and protection awareness among HCWs should be enhanced.

Seed reserves play vital roles in seed germination and seedling growth and their variation may be related to various environment factors, plant traits and phylogenetic history. Here, the evolutionary correlation associated with seed mass and altitude and carbon (C), nitrogen (N) and phosphorus (P) allocation of seeds among 253 alpine herbaceous plants was tested. In this study, phylogeny had strong limitations on nutrient allocation of seeds across species, and species from younger phylogenetic groups tended to have higher N and P contents, which might be considered as the evolutionary selection of seed plants. Higher seed N and P content would help seedlings to gain more survival chance and stronger competitive capacity, and their progeny would be more likely to be preserved. When phylogeny was considered, altitude only had a significant positive effect on P content, but the negative effects on seed mass were all expressed. The independent effects of altitude and seed mass suggest that the nutrient allocation of seeds might be affected by both environment and plant traits. In addition, altitude and seed mass displayed partial overlapping effects on nutrient allocation of seeds. The negative effects of seed mass were affected slightly by altitude, whereas altitude only had a significant positive effect on P content when seed mass was controlled. Above all, seed P content showed obvious and general correlations with seed mass, altitude and age of clade, which indicated that higher seed P content might be an adaptive selection of species associated with growth and survival of progeny.

Let $\mathbb{N}$ be the set of all nonnegative integers. For any set $A\subset \mathbb{N}$ , let $R(A,n)$ denote the number of representations of $n$ as $n=a+a^{\prime }$ with $a,a^{\prime }\in A$ . There is no partition $\mathbb{N}=A\cup B$ such that $R(A,n)=R(B,n)$ for all sufficiently large integers  $n$ . We prove that a partition $\mathbb{N}=A\cup B$ satisfies $|R(A,n)-R(B,n)|\leq 1$ for all nonnegative integers $n$ if and only if, for each nonnegative integer  $m$ , exactly one of $2m+1$ and $2m$ is in  $A$ .

For thixoforming, it is necessary to have a good microstructure of fine, uniform, and globular grains in a semisolid range. In this study, the nano-Al2O3(Al2O3np)/Al7075 composites with a high solid fraction were fabricated by specially made Al2O3np containing Mg powders and semisolid ultrasonic vibration (SSUV) process. The influence of SSUV technology on primary α-Al grain and second phase in the composites was investigated. Microstructural studies revealed that a good semisolid slurry with an average grain size of 73 μm, a shape factor of 0.84, and a solid fraction of 0.715 could be obtained. Also, it could be shown that SSUV affected largely the size and type of the second phase as well as growth and nucleation of the primary α-Al grain. TEM analysis revealed that there are well-defined crystallographic orientation relationships between the second phases and α-Al, suggesting enhanced heterogeneous nucleation in Al7075 alloys. Moreover, mechanisms involved in the development of microstructure were discussed.

High-entropy ceramic (HEC) films refer to the carbide, boride, oxide, or nitride films of the high-entropy alloy, which have potential applications under high temperatures. In this study, we fabricated the HEC NbTiAlSiZrNx films using magnetron sputtering under various deposition atmospheres. The phase structure evolution and the mechanical properties of three HEC films under high temperatures were investigated. The HEC films demonstrated good thermal stability as well as high hardness. After annealing for 24 h at 700 °C, the films remained in an amorphous phase without obvious crystallization, and the hardness of the films declined. Nanocrystallizations occurred in films deposited at a nitrogen flow rate of 4 sccm and 8 sccm after annealing for 30 min at 900 °C and exhibited an face-centered cubic structure. HEC NbTiAlSiZrNx films have potential applications as protective coatings under high temperatures.

Ga2−xFexO3 (GFO) bulks with x from 0.7 to 1.3 have been fabricated using the classic solid-state route. The structural, optical, and magnetic properties have been investigated systematically. X-ray diffraction spectra and FULLPROF profile fitting indicate that GFO bulks belong to the orthorhombic structure with the space group Pc21n. Phase separation appears at the Fe content of x = 1.3. The optical bandgap decreases almost linearly with the increase of iron content, which means that the bandgap of GFO bulks can be controlled by adjusting the Fe content in the samples. The magnetic property measurements suggest that GFO is ferromagnetic, and the magnetic properties are enhanced compared with other reported works, exhibiting the application in ferromagnetic semiconductors devices.

In this addendum we provide further information on our results and findings as well as explanations and suggestions in relation to the low R2. Table 1 provides additional information i.e., the standard error of all estimates, exact p values instead of asterisks as the significance level on the base of Table 3 in the published manuscript.

Blue-ice areas (BIAs) and their geographical distribution in Antarctica were mapped using Landsat-7 ETM+ images with 15 m spatial resolution obtained during the 1999–2003 austral summers and covering the area north of 82.5° S, and a snow grain-size image of the MODIS-based Mosaic of Antarctica (MOA) dataset with 125 m grid spacing acquired during the 2003/04 austral summer from 82.5°S to the South Pole. A map of BIAs was created with algorithms of thresholds based on band ratio and reflectance for ETM+ data and thresholds based on snow grain size for the MOA dataset. The underlying principle is that blue ice can be separated from snow or rock by their spectral discrepancies and by different grain sizes of snow and ice. We estimate the total area of BIAs in Antarctica during the data acquisition period is 234 549 km2, or 1.67% of the area of the continent. Blue ice is scattered widely over the continent but is generally located in coastal or mountainous regions. The BIA dataset presented in this study is the first map covering the entire Antarctic continent sourced solely from ETM+ and MODIS data. This dataset can potentially benefit other studies in glaciology, meteorology, climatology and paleoclimate, meteorite collection and airstrip site selection.