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Laser interaction with an ultra-thin pre-structured target is investigated with the help of both two-dimensional and three-dimensional particle-in-cell simulations. With the existence of a periodic structure on the target surface, the laser seems to penetrate through the target at its fundamental frequency even if the plasma density of the target is much higher than the laser’s relativistically critical density. The particle-in-cell simulations show that the transmitted laser energy behind the pre-structured target is increased by about two orders of magnitude compared to that behind the flat target. Theoretical analyses show that the transmitted energy behind the pre-structured target is actually re-emitted by electron ‘islands’ formed by the surface plasma waves on the target surfaces. In other words, the radiation with the fundamental frequency is actually ‘surface emission’ on the target rear surface. Besides the intensity of the component with the fundamental frequency, the intensity of the high-order harmonics behind the pre-structured target is also much enhanced compared to that behind the flat target. The enhancement of the high-order harmonics is also related to the surface plasma waves generated on the target surfaces.
Co-receptor tropism has been identified to correlate with HIV-1 transmission and the disease progression in patients. A molecular epidemiology investigation of co-receptor tropism is important for clinical practice and effective control of HIV-1. In this study, we investigated the co-receptor tropism on HIV-1 variants of 85 antiretroviral-naive patients with Geno2pheno algorithm at a false-positive rate of 10%. Our data showed that a majority of the subjects harboured the CCR5-tropic virus (81.2%, 69/85). No significant differences in gender, age, baseline CD4+ T-cell counts and transmission routes were observed between subjects infected with CXCR4-tropic or CCR5-tropic virus. The co-receptor tropism appeared to be associated with the virus genotype; a significantly more CXCR4-use was predicted in CRF01_AE infections whereas all CRF07_BC and CRF08_BC were predicted to use CCR5 co-receptor. Sequences analysis of V3 revealed a higher median net charge in the CXCR4 viruses over CCR5 viruses (4.0 vs. 3.0, P < 0.05). The predicted N-linked glycosylation site between amino acids 6 and 8 in the V3 region was conserved in CCR5 viruses, but not in CXCR4 viruses. Besides, variable crown motifs were observed in both CCR5 and CXCR4 viruses, of which the most prevalent motif GPGQ existed in both viral tropism and almost all genotypes identified in this study except subtype B. These findings may offer important implications for clinical practice and enhance our understanding of HIV-1 biology.
The aim of the study was to investigate any association between extrauterine growth restriction (EUGR) and intestinal flora of <30-week-old preterm infants. A total of 59 preterm infants were assigned to EUGR (n=23) and non-EUGR (n=36) groups. Intestinal bacteria were compared by using high-throughput sequencing of bacterial rRNA. The total abundance of bacteria in 344 genera (7568 v. 13,760; P<0.0001) and 456 species (10,032 v. 18,240; P<0.0001) was significantly decreased in the EUGR group compared with the non-EUGR group. After application of a multivariate logistic model and adjusting for potential confounding factors, as well as false-discovery rate corrections, we found four bacterial genera with higher and one bacterial genus with lower abundance in the EUGR group compared with the control group. In addition, the EUGR group showed significantly increased abundances of six species (Streptococcus parasanguinis, Bacterium RB5FF6, two Klebsiella species and Microbacterium), but decreased frequencies of three species (one Acinetobacter species, Endosymbiont_of_Sphenophorus_lev and one Enterobacter_species) compared with the non-EUGR group. Taken together, there were significant changes in the intestinal microflora of preterm infants with EUGR compared to preterm infants without EUGR.
Pathogenesis of pregnancy toxemia (PT) is believed to be associated with the disruption of lipid metabolism. The present study aimed to explore the underlying mechanisms of lipid metabolism disorder in the livers of ewes with PT. In total, 10 pregnant ewes were fed normally (control group) whereas another 10 were subjected to 70% level feed restriction for 15 days to establish a pathological model of PT. Results showed that, as compared with the controls, the levels of blood β-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFAs) and cholesterol were greater (P<0.05) and blood glucose level was lower (P<0.05) in PT ewes. The contents of NEFAs, BHBA, cholesterol and triglyceride were higher (P<0.05) and glycerol content was lower (P<0.05) in hepatic tissues of PT ewes than those of the controls. For ewes with PT, excessive fat vacuoles were observed in liver sections stained with hematoxylin–eosin; furthermore, inner structures of hepatocytes including nuclei, mitochondria and endoplasmic reticulum were damaged seriously according to the results of transmission electron microscope. Real-time PCR data showed that compared with the controls, the expression of hepatic genes involved in fatty acid oxidation (FAO) and triglyceride synthesis (TGS) was enhanced (P<0.05) whereas that related to acetyl-CoA metabolism (ACM) was repressed (P<0.05) in PT ewes. Generally, our results showed that negative energy balance altered the expression of genes involved in FAO, ACM and TGS, further caused lipid metabolism disorder in livers, resulting in PT of ewes. Our findings may provide the molecular basis for novel therapeutic strategies against this systemic metabolic disease in sheep.
High-precision response of the surrogate model is desired in the process of optimisation. An excessive number of sampling points will increase the cost of the calculation. The appropriate number of sampling points cannot only guarantee the accuracy of the surrogate model but also save the calculation cost. The purpose of this research is to demonstrate the eventuality of using an adaptive surrogate model for optimisation problems. The adaptive surrogate model is built on an adaptive sampling approach and an extended radial basis function (ERBF). The adaptive sampling is an approach that new sampling points are placed in the blank area and all the sampling points are uniformly distributed in the design region using Multi-Island GA. The precision of the ERBF surrogate model is checked using standard error measure to determine whether the surrogate model should be updated or not. This adaptive surrogate model is used to optimise a cruise missile head shape. Aerodynamic and stealthy performance of the cruise missile head shape are considered in this research. Different global objective function and different weight factor are used to research the aerodynamic and stealthy performance in this optimisation process. The results show that the drag is reduced with a slender head shape and the radar-cross section (RCS) value is reduced with a short head shape.
The present study evaluated the effects of isovalerate supplementation on the development of the small intestinal mucosa in dairy calves. Forty-eight Chinese Holstein bull calves at 15 days of age and 45.1 ± 0.36 kg of body weight were assigned randomly to four groups. The treatments were control, low-isovalerate, moderate-isovalerate and high-isovalerate with 0, 3, 6 and 9 g isovalerate per calf per day, respectively. The study comprised 75 days with a 15-day adaptation period followed by a 60-day sampling period. Calves were weaned at 60 days of age. Six calves were chosen from each treatment at random and slaughtered at 30 and 90 days of age. The small intestine morphology and activities of amylase and trypsin improved significantly with increasing age. No interaction between treatments and age was observed. The small intestine length, mucosa layer thickness, villus height and crypt depth increased linearly with increasing isovalerate supplementation. However, the ratio of villus height to crypt depth was not affected by treatment. Activities of amylase and trypsin increased linearly. The lactase activity increased linearly during the 75-day period and for pre-weaned calves but was unaltered for post-weaned calves. The relative mRNA expressions of growth hormone receptor, insulin-like growth factor-1 receptor and sodium-glucose co-transporter-1 in the small intestine mucosa increased linearly, and a similar pattern was observed for the expression of peptide transporter-1 in the duodenum and proximal jejunum. The results suggested that small intestine development was promoted by isovalerate in a dose-dependent manner.
In this paper, a new type of fixed-wing vertical take-off and landing, unmanned aerial vehicle (UAV) has been designed. Thrust-vector direct force control has been introduced in three axes to make UAV exhibit superior manoeuverability in transition flight. Considering the characteristics of UAV's dynamic model, which are non-linear, non-affine, and have redundant input, a two-stage progressive optimal control allocation method is developed, which can optimise position and attitude control in synthetical, and motivate effectors to generates desired force and moments. A task-oriented weight selection scheme is proposed to make objective function suitable for different tasks and flight conditions. In addition, a general constraint strategy is designed to guarantee the feasibility of optimal allocation results, which can largely reduce the onboard computation time. Simulations show that UAV can adjust flight attitude and use control effectors in an optimal way, and demonstrating satisfactory tracking of low-speed high-manoeuver flight paths.
The origins and phylogeny of different sheep breeds has been widely studied using polymorphisms within the mitochondrial hypervariable region. However, little is known about the mitochondrial DNA (mtDNA) content and phylogeny based on mtDNA protein-coding genes. In this study, we assessed the phylogeny and copy number of the mtDNA in eight indigenous (population size, n=184) and three introduced (n=66) sheep breeds in China based on five mitochondrial coding genes (COX1, COX2, ATP8, ATP6 and COX3). The mean haplotype and nucleotide diversities were 0.944 and 0.00322, respectively. We identified a correlation between the lineages distribution and the genetic distance, whereby Valley-type Tibetan sheep had a closer genetic relationship with introduced breeds (Dorper, Poll Dorset and Suffolk) than with other indigenous breeds. Similarly, the Median-joining profile of haplotypes revealed the distribution of clusters according to genetic differences. Moreover, copy number analysis based on the five mitochondrial coding genes was affected by the genetic distance combining with genetic phylogeny; we also identified obvious non-synonymous mutations in ATP6 between the different levels of copy number expressions. These results imply that differences in mitogenomic compositions resulting from geographical separation lead to differences in mitochondrial function.
The current experiment was conducted to evaluate the effects of different dietary protein levels and rumen-protected folic acid (RPFA) supplementation on ruminal fermentation, microbial enzyme activity, bacterial populations and urinary excretion of purine derivatives (PD) in growing beef steers. Low-protein (LP) or high-protein (HP) diets were fed to eight ruminally cannulated first-generation cross-bred (Blonde d'Aquitaine × Simmental) beef steers with or without RPFA supplementation. Steers were fed a total mixed ration, and dietary concentrate to maize silage ratio was 50 : 50 (dry matter (DM) basis). No interaction between dietary crude protein (CP) levels and RPFA supplementation was observed during the experiment. Ruminal pH was unaffected by RPFA supplementation, but decreased with increasing dietary CP levels. Ruminal total volatile fatty acid concentration increased with increasing dietary CP levels or RPFA supplementation. Molar proportion of acetate increased with RPFA supplementation, but tended to decrease with increasing dietary CP levels. The proportion of propionate decreased with RPFA supplementation, but was unaffected by dietary CP levels. As a result, the acetate to propionate ratio increased with RPFA supplementation, but tended to be lower for the HP diets than the LP diets. Ammonia-nitrogen content decreased with RPFA supplementation, but increased with increasing dietary CP levels. In situ ruminal degradability of maize straw and concentrate increased with increasing dietary CP levels or RPFA supplementation. Microbial enzyme (carboxymethyl-cellulase, cellobiase, xylanase, pectinase, α-amylase and protease) activity, bacterial populations (Ruminococcus albus, Ruminococcus flavefaciens, Butyrivibrio fibrisolvens, Prevotella ruminicola, Fibrobacter succinogenes and Ruminobacter amylophilus) and urinary PD excretion increased with increasing dietary CP levels or RPFA supplementation. The current study showed that increasing dietary CP levels from 109·1 to 130·7 g/kg DM or supplementing 75 mg RPFA improved ruminal fermentation and microbial protein synthesis by increasing bacterial population and microbial enzyme activity.
Optimal nitrogen (N) management for maize in the film-mulched production systems that are widely used in dryland agriculture is difficult because top-dressing N is impractical. The current research determined how matching N supply and demand was achieved before and after silking stages, when single applications of controlled release urea (CRU) were combined with conventional urea in film-mulched maize production. The CRU: urea mixture was applied in a 1 : 2 or 2 : 1 ratio and all three fertilizer regimes (urea alone and CRU: urea at 1 : 2 or 2 : 1) were applied at N rates of 180 and 240 kg/ha over 2 years. The 1 : 2 CRU: urea mixture, applied once at 180 kg N/ha, was found to synchronize N supply with demand, thereby reducing N losses. The highest grain yields (11·8–12·0 t/ha), N uptake (232–239 kg/ha), N recovery (65·8–67·7%) and high net economic return were achieved with this regime. These results indicate that a single application of a mixture of CRU and urea can synchronize N supply with demand and provide higher yields and profits than conventional N fertilization in film-mulched maize systems.
A study on effective thermal conductivity (ETC) of natural ice in a reservoir with <3% gas content and ∼300 mg L−1 dissolved matter content in the parent water was conducted in a laboratory. Ice sections were prepared to obtain the ice crystal structure, gas bubble content and ice density. Profiles of horizontal and vertical thermal conductivity of ice samples were determined with attention to relatively high temperature spanning 0 to –10°C. A detailed comparative analysis was conducted of the effects on ETC of direction, ice crystal structure, gas bubbles and temperature. Gas inclusions had little impact on the thermal conductivity of natural reservoir ice due to their quite low content (<3%). At high ice temperature the ETC decreases remarkably as ice temperature approaches the melting point, as the ETC of sea ice does due to its brine volume at ice temperature approaching its melting point. The measured conductivities for temperatures higher than –4°C were less than expected from previous work on saline ice. Whether this was due to the measurement techniques or actual properties of the reservoir ice is not clear. The present findings could lead to better understanding of the thermal processes of ice in natural freshwater bodies.
The objective of this study was to evaluate the performance of a Crop Circle sensor-based precision nitrogen (N) management (PNM) strategy in different winter wheat cropping systems under on-farm conditions in North China Plain (NCP). Four farmer’s fields were selected for on-farm experiments in Laoling County, Shandong Province of NCP in 2015-2016. In each field, the PNM strategy was evaluated in two winter wheat cropping systems: farmer’s conventional management (FCM) and regional optimum crop management (ROCM). In each cropping system, there were two N management strategies: 1) FCM or ROCM; 2) PNM. The results indicated that the PNM strategy significantly increased partial factor productivity (PFP) by 29% in the FCM system, but did not have any significant improvement in the ROCM system. The ROCM system, using either regional optimum N management or PNM, significantly increased both grain yield and PFP than the FCM system.
Worldwide 350 million people suffer from major depression, with the majority of cases occurring in low- and middle-income countries. We examined the patterns, correlates and care-seeking behaviour of adults suffering from major depressive episode (MDE) in China.
A nationwide study recruited 512 891 adults aged 30–79 years from 10 provinces across China during 2004–2008. The 12-month prevalence of MDE was assessed by the Modified Composite International Diagnostic Interview-short form. Logistic regression yielded adjusted odds ratios (ORs) of MDE associated with socio-economic, lifestyle and health-related factors and major stressful life events.
Overall, 0.7% of participants had MDE and a further 2.4% had major depressive symptoms. Stressful life events were strongly associated with MDE [adjusted OR 14.7, 95% confidence interval (CI) 13.7–15.7], with a dose–response relationship with the number of such events experienced. Family conflict had the highest OR for MDE (18.9, 95% CI 16.8–21.2) among the 10 stressful life events. The risk of MDE was also positively associated with rural residency (OR 1.5, 95% CI 1.4–1.7), low income (OR 2.3, 95% CI 2.1–2.4), living alone (OR 2.6, 95% CI 2.3–3.0), smoking (OR 1.4, 95% CI 1.3–1.6) and certain other mental disorders (e.g. anxiety, phobia). Similar, albeit weaker, associations were observed with depressive symptoms. Among those with MDE, about 15% sought medical help or took psychiatric medication, 15% reported having suicidal ideation and 6% reported attempting suicide.
Among Chinese adults, the patterns and correlates of MDE were generally consistent with those observed in the West. The low rates of seeking professional help and treatment highlight the great gap in mental health services in China.
Isobutyrate supplements could improve rumen development by increasing ruminal fermentation products, especially butyrate, and then promote the growth performance of calves. The objective of this study was to evaluate the effects of isobutyrate supplementation on growth performance, rumen development, blood metabolites and hormone secretion in pre- and post-weaned dairy calves. In total, 56 Chinese Holstein male calves with 30 days of age and 72.9±1.43 kg of BW, blocked by days of age and BW, were assigned to four groups in a randomized block design. The treatments were as follows: control, low-isobutyrate, moderate-isobutyrate and high-isobutyrate with 0, 0.03, 0.06 and 0.09 g isobutyrate/kg BW per calf per day, respectively. Supplemental isobutyrate was hand-mixed into milk of pre-weaned calves and the concentrate portion of post-weaned calves. The study consisted of 10 days of an adaptation period and a 50-day sampling period. Calves were weaned at 60 days of age. Seven calves were chosen from each treatment at random and slaughtered at 45 and 90 days of age. BW, dry matter (DM) intake and stomach weight were measured, samples of ruminal tissues and blood were determined. For pre- and post-weaned calves, DM intake and average daily gain increased linearly (P<0.05), but feed conversion ratio decreased linearly (P<0.05) with increasing isobutyrate supplementation. Total stomach weight and the ratio of rumen weight to total stomach weight tended to increase (P=0.073) for pre-weaned calves and increased linearly (P=0.021) for post-weaned calves, whereas the ratio of abomasum weight to total stomach weight was not affected for pre-weaned calves and decreased linearly (P<0.05) for post-weaned calves with increasing isobutyrate supplementation. Both length and width of rumen papillae tended to increase linearly for pre-weaned calves, but increased linearly (P<0.05) for post-weaned calves with increasing isobutyrate supplementation. The relative expression of messenger RNA for growth hormone (GH) receptor and 3-hydroxy-3-methylglutaryl-CoA synthase 1 in rumen mucosa increased linearly (P<0.05) for pre- and post-weaned calves with increasing isobutyrate supplementation. Blood concentrations of glucose, acetoacetate, β-hydroxybutyrate, GH and IGF-1 increased linearly (P<0.05) for pre- and post-weaned calves, whereas blood concentration of insulin decreased linearly with increasing isobutyrate supplementation. The present results indicated that isobutyrate promoted growth of calves by improving rumen development and its ketogenesis in a dose-dependent manner.
In this work, we studied the photon emission in the visible light range for Xeq+ ions of different charge states (10 ≤ q ≤ 21) bombardment on an aluminum target at 410 keV. During the interactions, the spectra in wavelength range 300–500 nm are recorded, including the photons from Al atoms and neutralized Xe+ ions. The yield of the visible light strongly depends on the projectile charge states. Its variation tendency with the charge states is similar to that of the potential energy variation. In addition, the experimental results also indicate that when the incident charge state is less than the critical charge state, it obeys the staircase classical-over-barrier model.
The objective of the present study was to evaluate the effects of isovalerate supplementation on growth performance and ruminal fermentation in pre- and post-weaning dairy calves. Forty-eight Chinese Holstein male calves at 15 days of age and 45·1 ± 0·36 kg body weight (BW) were assigned randomly to four groups. The treatments were: control, low-isovalerate, moderate-isovalerate (MIV) and high-isovalerate (HIV) with 0, 3, 6 and 9 g isovalerate per calf per day, respectively. Isovalerate was hand-mixed into milk in pre-weaning calves and the concentrate portion in post-weaning calves. The study lasted 75 days, including a 15-day adaptation period followed by a 60-day sampling period. Weaning was conducted when calves were 60 days old. Six calves were chosen from each treatment at random and slaughtered at 30 and 90 days of age. Average daily weight gain increased linearly whether during pre-weaning or post-weaning period with increasing isovalerate supplementation. Dry matter intake linearly increased at 90 days of age with increasing isovalerate supplementation. During weaning, ruminal pH and ammonia nitrogen (N) decreased linearly, whereas total ruminal volatile fatty acid concentration increased linearly with increasing isovalerate supplementation. The ratio of acetate to propionate increased linearly with increasing isovalerate supplementation due to increased acetate concentration and the unchanged propionate concentration. Activities of caboxymethyl-cellulase, cellobiase, xylanase and pectinase linearly increased at 90 days of age, α-amylase and β-amylase activities linearly increased at 30 and 90 days of age. Relative quantities of Butyrivibrio fibrisolvens, Ruminococcus albus, Fibrobacter succinogenes and Ruminococcus flavefaciens increased linearly with increasing isovalerate supplementation. Ruminal fermentation, enzyme activities and cellulolytic bacteria were higher for HIV and MIV than for the control. The present results indicate that isovalerate accelerated growth of calves by improving ruminal fermentation, microbial enzyme activities and cellulolytic bacteria growth during weaning. In the experimental conditions of the current trial, the optimum isovalerate dose was about 6·0 g isovalerate per calf per day.
We have studied DNA adduction with 14C-labeled nicotine and nicotine-derived nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), by accelerator mass spectrometry (AMS) in mouse liver at doses equivalent to low-level exposure of humans. The dose ranges of nicotine and NNK administered were from 0.4 μg to 4.0×102 μg kg b.w.-1, and from 0.1 μg to 2.0×104 μg kg b.w.-1, respectively. In the exposure of mice to either nicotine or NNK, the number of DNA adducts increased linearly with increasing dose. The detection limit of DNA adducts was 1 adduct per 1011 nucleotide molecules. This limit is 1–4 orders of magnitude lower than that of other techniques used for quantification of DNA adducts. The results of our animal experiments enabled us to speculate that nicotine is a potential carcinogen. According to the procedure for 14C-labeled-NNK synthesis, we discuss the ultimate chemical speciation of NNK bound to DNA. From the animal tests we derived a directly perceivable relation between tobacco consumption and DNA adduction as the carcinogenic risk assessment.
Soluble starch synthase II (SSII) plays an important role in the biosynthesis of starch and in rice it consists of three isoforms encoded by SSII-1, SSII-2 and SSII-3. However, the genetic effects of various SSII alleles on grain quality have not been systematically characterized. In the present study, the japonica alleles on SSII-1, SSII-2 and SSII-3 (SSIIa) loci from a japonica cultivar, Suyunuo, were respectively introgressed by molecular marker-assisted selection into a typical indica cultivar, Guichao2, through successive backcrossing, generating three sets of near-isogenic lines (NILs). Grain quality and starch property analysis showed that NIL-SSII-3j exhibited significant decreases in the following parameters: amylose content, average granule size, and setback viscosity and consistency; but increases in peak viscosity, hot paste viscosity, gelatinization temperature and relative crystallinity. Moreover, the proportion of short amylopectin chains and branching degree also increased when compared with those of NIL-SSII-3i (Guochao2). Similar effects were observed in NIL-SSII-1j, and certain alterations in the fine structure of starch (granule size) were revealed. However, NIL-SSII-2j did not exert significant effect on grain quality and starch properties. In brief, among the SSII gene family, the functional diversity occurred on SSII-1 and SSII-3, and not on SSII-2. Therefore, it appears that more attention should be directed to SSII-1 and SSII-3 loci for improving the eating and cooking quality of rice.
The B type star 53 Persei was discovered in 1977 by Smith (1977) as the prototype of a separate group of B-type variables showing light and line profile variability. The physical cause of the variability was thought to be nonradial pulsation (NRP) (see, e.g. Smith et al. 1984). However, the NRP model for this star has been questioned by Balona (1986) who suggested the rotational modulation (RM) model to explain the variability. In order to resolve the long lasting debate about 53 Persei, a campaign was initiated to organize coordinated optical photometry and spectroscopy from the ground, and Far-UV photometry from Voyager in 1991 January. This paper presents the results of period analysis on the groundbased UBV data. In another paper, Smith & Huang (1994) report the new identification of pulsation modes using Voyager Far-UV photometry combined with the results from optical observations. Some preliminary results from APT uvby observations taken at a single site are also cited for comparison.
ET And is a binary system with a B9 Si star as the main component (Porb = 48.308d, e=0.46). Controversial claims in the literature concerning pulsation with periods ranging from few minutes to few hours and with variable amplitudes indicated a challenging target and motivated us to organize several photometric and spectroscopic observing campaigns. The problem with pulsation of ET And is that Teff and log g put this star in the cool domain of Slowly Pulsating B-type (SPB) stars, but the pulsation periods would be too short by a factor of about four, relatively to the shortest hitherto known periods for SPB stars.