As a basic flow model for engineering applications, wall-bounded turbulent flow has been widely studied in the field of aero-optics, but the flow control methods that could effectively suppress aero-optical effects are relatively rare. As an urgent requirement in engineering application, the concept of the steady wall blowing and suction is proposed by the author. Firstly, the author briefly described the flow model and physical method. Secondly, the choice of disturbance type is given. Then, the results of wall blowing-suction, suction and blowing ways based on steady and unsteady disturbance are compared. Finally, it is concluded that employing the high steady wall blowing disturbance (A = 0.2) could realise aero-optical suppression by around 20%. Besides, the steady wall suction scheme contributes to about 70%–80% reduction effect within a wide amplitude range (A = 0.2–1.0), which suppresses this effect by maintaining laminar state downstream contrasted by the baseline case.

The effect of sheared E × B flow on the blob dynamics in the scrape-off layer (SOL) of HL-2A tokamak has been studied during the plasma current ramp-up in ohmically heated deuterium plasmas by the combination of poloidal and radial Langmuir probe arrays. The experimental results indicate that the SOL sheared E × B flow is substantially enhanced as the plasma current exceeds a certain value and the strong sheared E × B flow has the ability to slow the blob radial motion via stretching its poloidal correlation length. The locally accumulated blobs are suggested to be responsible for the increase of plasma density just outside the Last Closed Flux Surface (LCFS) observed in this experiment. The results presented here reveal the significant role played by the strong sheared E × B flow on the blob dynamics, which provides a potential method to control the SOL width by modifying the sheared E × B flow in future tokamak plasmas.

Alanyl-glutamine (Ala-Gln), a highly soluble and stable glutamine dipeptide, is known to improve gut integrity and function. The aim of this study was to evaluate whether dietary Ala-Gln supplementation could improve growth performance, intestinal development and digestive-absorption function in weaned piglets. A total of 100 purebred Yorkshire piglets weaned at 21 days of age were assigned randomly to four dietary treatment groups and fed a basal diet (control group) or a basal diet containing 0.15%, 0.30% and 0.45% Ala-Gln, respectively. Compared with the control group, piglets fed the Ala-Gln diets had higher average daily gain and lower feed : gain and diarrhea rate (P < 0.05). Moreover, dietary Ala-Gln supplementation increased villous height and villous height : crypt depth ratio in duodenum and jejunum (P < 0.05), as well as the activities of maltase and lysozyme in jejunum mucosa (P < 0.05). In addition, a decrease in serum diamine oxidase activity and crypt depth in duodenum and jejunum was observed in piglets fed the Ala-Gln diets (P < 0.05). Serum cytosolic phospholipase A2 (cPLA2) concentration and gene expression of cPLA2, Na+-dependent glucose transporter 1, glucose transporter 2 and peptide transporter 1 in jejunum were increased by feeding Ala-Gln diets relative to control diet (P < 0.05). These results indicated that feeding Ala-Gln diet has beneficial effects on the growth performance of weaned piglets, which associated with maintaining intestinal morphology and digestive-absorption function.

Field surveys indicate that host population size, rather than density, is the most important determinant of monogenean infection dynamics. To verify this prediction, epidemic parameters were monitored for 70 days at five host population sizes held at constant density using a goldfish – Gyrodactylus kobayashii laboratory model. During the first 20 days, the rate of increase of prevalence and mean abundance was faster in small host populations. Total mean prevalence and total mean abundance throughout the experiment were not significantly affected by host population sizes. Higher transmission rates were detected in larger host populations. However, there were no significant differences in effective contact rates among the five host populations on each sampling day during the first 20 days, implying that contact rates may be saturated at a sufficiently high host density. These results demonstrate that the epidemic occurs more quickly in smaller host populations at the beginning of the experiment. However, the epidemic is independent of the host population size due to the similar effective contact rates in the five population sizes. Significant negative influence of the initial body condition (Kn) of uninfected goldfish on total mean abundance of parasites suggests that susceptibility of hosts is also a determinant of parasite transmission.

Mitochondria plays an important role in the regulation of energy homeostasis. Moreover, mitochondrial biogenesis accompanies skeletal myogenesis, and we previously reported that maternal high-energy diet repressed skeletal myogenesis in pig fetuses. Therefore, the aim of this study was to evaluate the effects of moderately increased maternal energy intake on skeletal muscle mitochondrial biogenesis and function of the pig fetuses. Primiparous purebred Large White sows were allocated to a normal energy intake group (NE) as recommended by the National Research Council (NRC) and a high energy intake group (HE, 110% of NRC recommendations). On day 90 of gestation, fetal umbilical vein blood and longissimus (LM) muscle were collected. Results showed that the weight gain of sows fed HE diet was higher than NE sows on day 90 of gestation (P<0.05). Maternal HE diet increased fetal umbilical vein serum triglyceride and insulin concentrations (P<0.05), and tended to increase the homeostasis model assessment index (P=0.08). Furthermore, HE fetuses exhibited increased malondialdehyde concentration (P<0.05), and decreased activities of antioxidative enzymes (P<0.05) and intracellular NAD+ level (P<0.05) in LM muscle. These alterations in metabolic traits of HE fetuses were accompanied by reduced mitochondrial DNA amount (P<0.05) and down-regulated messenger RNA expression levels of genes responsible for mitochondrial biogenesis and function (P<0.05). Our results suggest that moderately increased energy supply during gestation decreases mitochondrial biogenesis, function and antioxidative capacity in skeletal muscle of pig fetuses.

Seventeen non-lactating dairy-bred suckler cows (LF; Limousin×Holstein-Friesian) and 17 non-lactating beef composite breed suckler cows (ST; Stabiliser) were used to study enteric methane emissions and energy and nitrogen (N) utilization from grass silage diets. Cows were housed in cubicle accommodation for 17 days, and then moved to individual tie-stalls for an 8-day digestibility balance including a 2-day adaption followed by immediate transfer to an indirect, open-circuit, respiration calorimeters for 3 days with gaseous exchange recorded over the last two of these days. Grass silage was offered ad libitum once daily at 0900 h throughout the study. There were no significant differences (P>0.05) between the genotypes for energy intakes, energy outputs or energy use efficiency, or for methane emission rates (methane emissions per unit of dry matter intake or energy intake), or for N metabolism characteristics (N intake or N output in faeces or urine). Accordingly, the data for both cow genotypes were pooled and used to develop relationships between inputs and outputs. Regression of energy retention against ME intake (r2=0.52; P<0.001) indicated values for net energy requirements for maintenance of 0.386, 0.392 and 0.375 MJ/kg0.75 for LF+ST, LF and ST respectively. Methane energy output was 0.066 of gross energy intake when the intercept was omitted from the linear equation (r2=0.59; P<0.001). There were positive linear relationships between N intake and N outputs in manure, and manure N accounted for 0.923 of the N intake. The present results provide approaches to predict maintenance energy requirement, methane emission and manure N output for suckler cows and further information is required to evaluate their application in a wide range of suckler production systems.

Estimating crop nutrient requirements for winter oilseed rape (Brassica napus L.) is a crucial step in optimizing fertilization to enhance seed yield and improve fertilizer use efficiency. In the present paper, a database composed of 1035 on-farm observations collected from 2005 to 2010 across the major winter oilseed rape production regions in China was used to evaluate internal nutrient efficiencies (kg seed per kg nutrient in plant dry matter); then the Quantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) model for winter oilseed rape was developed to describe the nutrient uptake-yield relationship of oilseed rape over a wide range of environmental conditions and predict the nutrient requirements for a target yield. After excluding observations with low harvest index values, <0·20, and excluding 0·025 of the highest and lowest internal nutrient efficiencies, the minimum and maximum internal nutrient efficiencies were estimated as 13·1 and 31·6 kg seed/kg nitrogen (N), 68·9 and 200·3 kg seed/kg phosphorus (P) and 8·9 and 31·1 kg seed/kg potassium (K), respectively. On the basis of the data settings, the balanced N, P and K uptake at different yield potential levels was calculated using a linear–parabolic–plateau curve with the QUEFTS model. Crop nutrient requirements increased linearly until the yield reached approximately 0·60–0·70 of the potential yield, and 46·0 kg N, 8·0 kg P and 57·1 kg K were found to be needed to produce 1000 kg of seed. The corresponding internal nutrient efficiencies were 21·8, 125·1 and 17·5 kg seed/kg N, P and K, respectively. However, when the target yields approached the yield potential, a decrease in internal nutrient efficiencies was detected in the model. The predicted nutrient requirement values simulated by the QUEFTS model compared well with observed values across a range of conditions. To conclude, the QUEFTS model was shown to be a practical and robust tool for assessing the crop nutrient requirements of winter oilseed rape.

A high molecular weight protein (HMWP) was isolated and purified from sow milk, and some of its biochemical characteristics and biological functions were identified. The origin of HMWP was also investigated. The molecular weight of HMWP was determined to be about 115 000 and 114 800 by SDS-PAGE and gel filtration, respectively. The sequence of 10 amino acids in N-terminal of HMWP was Ala-Leu-Val-Gln-Ser-Cys-Leu-Asn-Leu-Val. The sequence was blasted against GenBank. No protein showed significant similarity with this sequence suggesting the HMWP may be novel. The result of liquid chromatography mass spectrometry (LC-MS) also proved HMWP could be a novel protein. By amino acid assay, HMWP was rich in glutamate (including glutamine), cysteine, glycine, aspartic acid (including asparagines) and proline. The content of hydrophobic amino acids (Ala, Val, Leu, Ile, Met, Phe and Pro) was lower at 18.59% of the total amino acids suggesting HMWP has high solubility in water. Western blots of lectins were used to identify the kinds of carbohydrate residues attached to HMWP qualitatively. The result showed that HMWP was a kind of glycoprotein containing N-acetylneuraminic acid (NeuNAc), mannose (Man) and/or N-acetylglucosamine (GlcNAc). By isoelectric focusing, HMWP pI was found to be 5.1. Compared with milk fat globule membrane protein (MFGMP) isolated from the sow milk in SDS-PAGE, MFGMP did not contain HMWP. HMWP was assumed to be a secretory milk protein. HMWP was not found in bovine, goat, rabbit or human milk in SDS-PAGE gel suggesting HMWP may be unique to sow milk. By Western blot, HMWP could be detected in sow milk, not in sow serum, which suggests it is synthesized and secreted by the mammary gland. HMWP concentrations in sows milk were the lowest in the first day of lactation, rose significantly during lactation 1 to 7 days. The HMWP content of sows milk remained relatively constant ((1.95±0.13) g/l) during lactation 7 to 20 days. HMWP significantly inhibited Escherichia coli in a dose related manner in vitro. Overall, HMWP could be a novel sow milk protein with implications for the mammary gland and the piglet.

New-type oilseed rape (Brassica napus, ArArCcCc) with introgressed exotic subgenomic components from Brassica rapa (ArAr) and Brassica carinata (BcBcCcCc) showed strong heterosis in both vegetative and reproductive growth. The aim of the current study was to analyse the tolerance of the new-type B. napus with different exotic subgenomic contents to low nitrogen (N) stress. Under hydroponic culture and pot experiments, root system parameters, photosynthetic parameters, relative chlorophyll concentration (SPAD values), biomass, seed yield, seed yield components, N concentration and expressions of genes involved in N transport and assimilation were determined with two new-type B. napus genotypes (N-efficient genotype D4-15 and N-inefficient genotype D1-1) under high-N and low-N levels. Furthermore, N accumulation, N transfer efficiency and N use efficiency (NUE) were analysed in the two genotypes. The hydroponic and potted growth tests showed consistent characteristics in N uptake and utilization efficiency at the seedling stage, and N-efficient genotype (D4-15) showed better growth phenotypes across cultured conditions and N levels. Under the low-N condition, D4-15 produced a larger root system and accumulated more N, and had higher N transfer efficiency and NUE than D1-1. Moreover, D4-15 had significantly higher photosynthetic parameters, photosynthetic NUE and expression levels of the N transporter genes, BnNRT1·1, BnNRT2·5, BnNRT2·7 and BnAMT1·1, in roots or leaves, as well as higher seed yield than that of D1-1 under low-N supply. These results indicated that the N-efficient new-type B. napus D4-15 possessed excellent adaptability to low-N stress, which may be attributed to the highly introgressed exotic subgenomic components from B. rapa and B. carinata, suggesting the possibility of identifying high-nutrient-efficiency germplasm from inter-specific hybrids.

Eating raw pork and/or liver is a custom of the Bai ethnic group in China. Most people living in Dali Bai Autonomous Prefecture, Yunnan Province, southwestern China are of Bai ethnicity. Little is known of the seroprevalence of Toxoplasma gondii in Bai and Han ethnic populations in this region. In the present survey, a total of 555 and 595 blood samples were obtained from Bai and Han ethnic groups in Dali urban and rural areas, respectively. Enzyme-linked immunosorbent assay was performed to examine T. gondii IgG antibodies. Total positive rate of anti-T. gondii IgG in Bai and Han groups in this region was 21·6% (248/1150). The total seroprevalence of T. gondii was significantly higher in the Bai ethnic group (32·3%, 179/555) than in the Han ethnic group (11·6%, 69/595) (P < 0·01). The results of statistical analysis indicated that there was no significant difference between cat feeding/non-cat feeding groups in the Bai ethnic group, the most important risk factor was consumption of raw pork and/or liver for the Bai group, but feeding a cat may be the main route of T. gondii infection for the Han group. Therefore, it is essential to implement integrated strategies to prevent and control T. gondii infection in this unique region of the world.

Satellite microwave measurements can penetrate through clouds and therefore provide unique information of surface and near-surface temperatures and surface emissivity. In this study, the brightness temperatures from NOAA-15 Advanced Microwave Sounding Unit-A (AMSU-A) are used to analyse the surface temperature variation in the Arctic and Antarctic regions during the past 13 years from 1998–2010. The data from four AMSU-A channels sensitive to surface are analysed with wavelet and Fourier spectrum techniques. A very pronounced maximum is noticed in the period range centred around four months. Application of a statistical significance test confirms that it is a dominant mode of variability over polar regions besides the annual and semi-annual oscillations in the data. No evidence of this feature could be found in middle and low latitudes. The four-month oscillation is 90° out of phase at the Arctic and Antarctic, with the Arctic four-month oscillation reaching its maximum in the beginning of March, July and November and the Antarctic four-month oscillation in the middle of April, August and December. The intensity of the four-month oscillation varies interannually. The years with pronounced four-month oscillation were 2002–03, 2005–06 and 2008–09. The strongest year for the Arctic and Antarctic four-month oscillations occurred in 2005–06 and 2008–09, respectively. The sign of four-month oscillation is also found in the surface skin temperatures and two-metre air temperatures from ERA-Interim reanalysis, with strongest signal in 2005–06 when this oscillation is strongest in the data. It is hypothesized that the Arctic and Antarctic four-month oscillations are a combined result of unique features of solar radiative forcing and snow/sea ice formation and metamorphosis.

We study the following nonlinear Dirichlet boundary value problem: where Ω is a bounded domain in ℝN(N ≥ 2) with a smooth boundary ∂Ω and g ∈ C(Ω × ℝ) is a function satisfying for all x ∈ Ω. Under appropriate assumptions, we prove the existence of infinitely many solutions when g(x, t) is not odd in t.

Contaminated water is one of the main sources of norovirus (NoV) gastroenteritis outbreaks globally. Waterborne NoV outbreaks are infrequently attributed to GII.4 NoV. In September 2009, a NoV outbreak affected a small school in Guangdong Province, China. Epidemiological investigations indicated that household use water, supplied by a well, was the probable source (relative risk 1·9). NoV nucleic acid material in concentrated well-water samples was detected using real-time RT–PCR. Nucleotide sequences of NoV extracted from diarrhoea and well-water specimens were identical and had the greatest sequence identity to corresponding sequences from the epidemic strain GII.4-2006b. Our report documents the first laboratory-confirmed waterborne outbreak caused by GII.4 NoV genotype in China. Our investigations indicate that well water, intended exclusively for household use but not for consumption, caused this outbreak. The results of this report serve as a reminder that private well water intended for household use should be tested for NoV.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhoea in neonatal and postweaning pigs. F41 is one of ETEC fimbriae that adhere to the small intestinal epithelium and lead to development of diarrhoea. The genetic architecture of susceptibility to ETEC F41 remains elusive in pigs. In this study, we determined the in vitro adhesion phenotypes of ETEC F41 in a total of 835 F2 animals from a White Duroc × Erhualian intercross, and performed a genome scan using both F2 and half-sib analyses with 183 microsatellite markers to detect quantitative trait loci (QTL) for porcine susceptibility to ETEC F41. The two analyses consistently revealed a 1% genome-wide significant QTL on pig chromosome 4. Moreover, we determined F41 adhesion phenotypes in 14 purebred Erhualian and 14 White Duroc pigs. The results showed that both the founder breeds are segregating for the F41 adhesion phenotype, while less percentage of Erhualian pigs were adhesive to ETEC F41 compared to White Duroc pigs.

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009