To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural–geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.
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.
To control hepatitis A spread by vaccination, accurate estimation of transmissibility is vital. Regan et al. (2016) proposed a model of hepatitis A virus (HAV) transmission and used least squares to calibrate model to the 1991/1992 HAV outbreak in men who have sex with men (MSM) in Sydney, Australia. Based on the estimate of R0, they obtained the critical immunity of 70% and showed that when the proportion immune <70%, there is a definite chance for outbreaks to take place. The immunity level from previous surveys ranges from 32% to 64% after 1996 while no outbreaks in Australian MSMs have been reported since 1996. Further noticing the ill-distributed parameters, we argue that their estimate of R0 is not accurate. In this study, we revisited their model by Bayesian inference, which has privilege over least squares. We obtained the appropriate posterior distributions of parameters and the estimate of R0 ranges from 1.38 to 2.89, indicating a critical immunity of 65%. The reduction in critical immunity and outbreak probabilities predicts the absence of outbreaks in Australian MSMs since 1996. Our study shows the importance of using appropriate methods to provide reliable and accurate estimates of the model parameters especially the transmissibility.
The takeoff-mass of a two-stage-to-orbit Rocket-Based Combined Cycle Engine-Rocket (RBCC-RKT) launch vehicle is a crucial factor in its comprehensive performance. This paper optimizes the takeoff-mass together with the trajectory by reformulating it to a nonlinear optimal control problem. The range of the second stage rocket mass is considered as a process constraint. When the scopes of initial and terminal states are specified, the problem can be solved by using the Gauss pseudo-spectral method (GPM). In order to reduce the convergent difficulty caused by using table data, the data in different stages are utilized by employing an integrated interpolation strategy through the optimization. Simulation results show that the mass can be effectively optimized to meet the inertia mass ratio constraint of the first-stage, and the separation of Mach number and altitude can be optimized at the same time.
Predicting mental workload of pilots can provide cockpit designers with useful information to reduce the possibility of pilot error and cost of training, improve the safety and performance of systems, and increase operator satisfaction. We present a theoretical model of mental workload, using information theory, based on review investigations of how effectively task complexity, visual performance, and pilot experience predict mental workload. The validity of the model was confirmed based on data collected from pilot taxiing experiments. Experiments were performed on taxiing tasks in four different scenarios. Results showed that predicted values from the proposed mental workload model were highly correlated to actual mental workload ratings from the experiments. The findings indicate that the proposed mental workload model appears to be effective in the prediction of pilots’ mental workload over time.
To compare the epidemiologic features (e.g. settings and transmission mode) and patient clinical characteristics associated with outbreaks of different norovirus (Nov) strains, we retrospectively analysed data of Nov outbreaks occurring in Guangzhou, China from 2012 to 2018. The results suggested that outbreaks of Nov GII.2, GII.17 and GII.4 Sydney exhibited different outbreak settings, transmission modes and symptoms. GII.2 outbreaks mainly occurred in kindergartens, elementary and high schools and were transmitted mainly through person-to-person contact. By contrast, GII.4 Sydney outbreaks frequently occurred in colleges and were primarily associated with foodborne transmission. Cases from GII.2 and GII.17 outbreaks reported vomiting more frequently than those from outbreaks associated with GII.4 Sydney.
Optimizing the dietary calcium (Ca) level is essential to maximize the eggshell quality, egg production and bone formation in poultry. This study aimed to establish the Ca requirements of egg-type duck breeders from 23 to 57 weeks of age on egg production, eggshell, incubation, tibial, plasma and ovary-related indices, as well as the expression of matrix protein-related genes. Totally, 450 Longyan duck breeders aged 21 weeks of age were allotted randomly into five treatments, each with six replicates of 15 individually caged birds. The data collection started from 23 weeks of age and continued over the following 35 weeks. The five groups corresponded to five dietary treatments containing either 2.8%, 3.2%, 3.6%, 4.0% or 4.4% Ca. The tested dietary Ca levels increased (linear, P <0.01) egg production and egg mass, and linearly improved (P <0.01) the feed conversion ratio (FCR). Increasing the dietary Ca levels from 2.8% to 4.4% increased (P <0.01) the eggshell thickness and eggshell content. The tested Ca levels showed a quadratic effect on eggshell thickness and ovarian weight (P <0.01); the highest values were obtained with the Ca levels 4.0% and 3.6%, respectively. Dietary Ca levels affected the small yellow follicles (SYF) number and SYF weight/ovarian weight, and the linear response (P <0.01) was significant vis-à-vis SYF number. In addition, dietary Ca levels increased (P <0.05) the tibial dry weight, breaking strength, mineral density and ash content. Plasma and tibial phosphorus concentration exhibited a quadratic (P <0.01) response to dietary Ca levels. Plasma calcitonin concentration linearly (P <0.01) increased as dietary Ca levels increased. The relative expression of carbonic anhydrase 2 in the uterus rose (P <0.01) with the increment of dietary Ca levels, and the highest value was obtained with 3.2% Ca. In conclusion, Longyan duck breeders fed a diet with 4.0% Ca had superior eggshell and tibial quality, while those fed a diet with 3.6% Ca had the heaviest ovarian weights. The regression model indicated that the dietary Ca levels 3.86%, 3.48% and 4.00% are optimal levels to obtain maximum eggshell thickness, ovarian weight and tibial mineral density, respectively.
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.
A series of nanostructured Fe/Ag metal films were produced at various substrate temperatures to determine their magnetic characteristics. The magnetic coercivity was found to increase with the diffracting-particle size which is process controlled. The films produced at low substrate temperature (<200°C) consisted of small metallic clusters of Ag (<100 Å). As the substrate temperature was increased, the films exhibited increased crystallinity and larger diffracting-particle size. The position of the maximum in the particlesize distribution function and the width of the function increased with substrate temperature.
X-ray diffraction topography is the name given to several x-ray diffraction techniques where large area x-ray beams diffracted from a crystal provide detailed information about the surface structure and internal perfection of crystal microstructures. Since x-ray topographic techniques are based on Bragg (reflection) or Laue (transmission) diffraction from a crystal lattice, they are extremely sensitive to any atomic lattice imperfections and strains. Alterations of the interplanar spacing as small as one part in ten thousand extending over a reasonable number of atomic ce11 lengths can be recorded as a corresponding change in the diffracted beam intensity. Line Modified-Asymmetric Crystal Topography (LM-ACT) is one such reflection technique that shows particular promise in Che field of microelectronics. The LM-ACT system is designed with low angular divergence in the x-ray beam probe. Low probe beam divergence allows details of device geometries on the order of microns to be resolved in the recorded x-ray intensity variation of the diffracted beam.
The LM-ACT system was applied here to the study of integrated circuits (IC) after specific processing steps were accomplished during IC fabrication and in the final product condition. Topographs obtained from specular crystal surfaces that were implanted through a patterned mask showed contrast variations between the implanted and non-implanted regions; details of the mask patterns have been resolved on the order of a few microns. LMACT topographs from annealed, and unannealed, Implanted specimens showed marked differences and as a result it is suggested that LM-ACT would be beneficial in optimizing the processing schedule for a particular wafer/electronic system. A significant feature of the LM-ACT technique is the capability for producing high resolution stereo-pair topographs that provide quantitative information through the depth of individual process layers in an integrated circuit.
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.
Music or other background sounds are often played in barns as environmental enrichment for animals on farms or to mask sudden disruptive noises. Previous studies looking at the effects of this practice on non-human animal well-being and productivity have found contradictory results. However, there is still a lack of discussion on whether piglets have the ability to distinguish different types of music. In this study, we exposed piglets to different music conditions to investigate whether the piglets preferred certain music types, in which case those types would have the potential to be used as environmental enrichment. In total, 30 piglets were tested for music type preference to determine whether growing pigs respond differently to different types of music. We used music from two families of instruments (S: string, W: wind) and with two tempos (S: slow, 65 beats/min (bpm); F: fast, 200 bpm), providing four music-type combinations (SS: string-slow; SF: string-fast; WS: wind-slow; WF: wind-fast). The piglets were given a choice between two chambers, one with no music and the other with one of the four types of music, and their behaviour was observed. The results showed that SS and WF music significantly increased residence time (P<0.01) compared with the other music conditions. Compared with the control group (with no music), the different music conditions led to different behavioural responses, where SS music significantly increased lying (P<0.01) and exploration behaviour (P<0.01); SF music significantly increased tail-wagging behaviour (P<0.01); WS music significantly increased exploration (P<0.01); and WF music significantly increased walking, lying, standing and exploration (all P<0.01). The results also showed that musical instruments and tempo had little effect on most of the behaviours. Fast-tempo music significantly increased walking (P=0.02), standing (P<0.01) and tail wagging (P=0.04) compared with slow-tempo music. In conclusion, the results of this experiment show that piglets are more sensitive to tempo than to musical instruments in their response to musical stimulation and seem to prefer SS and WF music to the other two types. The results also suggest a need for further research on the effect of music types on animals.
Subcutaneous immunotherapy is an effective and safe treatment for allergic rhinitis and allergic asthma. Different symptom scores are used to evaluate the efficacy of subcutaneous immunotherapy in clinical trials.
A total of 58 allergic rhinitis patients sensitised to house dust mites, with or without mild asthma, were included. Symptom score, medication score, visual analogue scale score and quality of life were assessed before and after 6, 12 and 24 months of subcutaneous immunotherapy.
After two years of subcutaneous immunotherapy, asthma symptom scores nearly reached zero, whereas the scores remained higher for nasal symptoms. The changes in asthma symptom scores were markedly different (p < 0.05) and occurred faster than the changes in nasal symptom scores when compared between monosensitised and polysensitised groups. Significant reductions in visual analogue scale score and medication score were demonstrated after subcutaneous immunotherapy.
Two-year subcutaneous immunotherapy with house dust mite vaccine is an effective treatment for both monosensitised and polysensitised allergic patients. The changes in asthma symptom scores were markedly different and occurred quicker than the changes in nasal symptom scores in Chinese house dust mite allergic patients.
Single-step genomic BLUP (ssGBLUP) has been widely used in genomic evaluation due to relatively higher prediction accuracy and simplicity of use. The prediction accuracy from ssGBLUP depends on the amount of information available concerning both genotype and phenotype. This study investigated how information on genotype and phenotype that had been acquired from previous generations influences the prediction accuracy of ssGBLUP, and thus we sought an optimal balance about genotypic and phenotypic information to achieve a cost-effective and computationally efficient genomic evaluation. We generated two genetically correlated traits (h2 = 0.35 for trait A, h2 = 0.10 for trait B and genetic correlation 0.20) as well as two distinct populations mimicking purebred swine. Phenotypic and genotypic information in different numbers of previous generations and different genotyping rates for each litter were set to generate different datasets. Prediction accuracy was evaluated by correlating genomic estimated breeding values with true breeding values for genotyped animals in the last generation. The results revealed a negligible impact of previous generations that lacked genotyped animals on the prediction accuracy. Phenotypic and genotypic data, including the most recent three to four generations with a genotyping rate of 40% or 50% for each litter, could lead to asymptotic maximum prediction accuracy for genotyped animals in the last generation. Single-step genomic best linear unbiased prediction yielded an optimal balance about genotypic and phenotypic information to ensure a cost-effective and computationally efficient genomic evaluation of populations of polytocous animals such as purebred pigs.
Muons produced by the Bethe–Heitler process from laser wakefield accelerated electrons interacting with high
materials have velocities close to the laser wakefield. It is possible to accelerate those muons with laser wakefield directly. Therefore for the first time we propose an all-optical ‘Generator and Booster’ scheme to accelerate the produced muons by another laser wakefield to supply a prompt, compact, low cost and controllable muon source in laser laboratories. The trapping and acceleration of muons are analyzed by one-dimensional analytic model and verified by two-dimensional particle-in-cell (PIC) simulation. It is shown that muons can be trapped in a broad energy range and accelerated to higher energy than that of electrons for longer dephasing length. We further extrapolate the dependence of the maximum acceleration energy of muons with the laser wakefield relativistic factor
and the relevant initial energy
. It is shown that a maximum energy up to 15.2 GeV is promising with
on the existing short pulse laser facilities.
An adverse early life environment is associated with increased cardiovascular disease in offspring. Work in animal models has shown that maternal undernutrition (UN) during pregnancy leads to hypertension in adult offspring, with effects thought to be mediated in part via altered renal function. We have previously shown that growth hormone (GH) treatment of UN offspring during the pre-weaning period can prevent the later development of cardiometabolic disorders. However, the mechanistic basis for these observations is not well defined. The present study examined the impact of GH treatment on renal inflammatory markers in adult male offspring as a potential mediator of these reversal effects. Female Sprague-Dawley rats were fed either a chow diet fed ad libitum (CON) or at 50% of CON intake (UN) during pregnancy. All dams were fed the chow diet ad libitum during lactation. CON and UN pups received saline (CON-S/UN-S) or GH (2.5 µg/g/day; CON-GH/UN-GH) from postnatal day 3 until weaning (p21). Post-weaning males were fed a standard chow diet for the remainder of the study (150 days). Histological analysis was performed to examine renal morphological characteristics, and gene expression of inflammatory and vascular markers were assessed. There was evidence of renal hypotrophy and reduced nephron number in the UN-S group. Tumour necrosis factor-α, monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecular-1 and vascular cell adhesion molecule-1 gene expression was increased in UN-S offspring and normalized in the UN-GH group. These findings indicate that pre-weaning GH treatment has the potential to normalize some of the adverse renal and cardiovascular sequelae that arise as a consequence of poor maternal nutrition.
The genus Megalobatrachonema is a rare group of nematode parasites within Ascaridida. The systematic status of Megalobatrachonema in the superfamily Cosmocercoidea (Ascaridida) has long been controversial. The relationship of Megalobatrachonema and Chabaudgolvania remains unsolved. In the present study, a new species of Megalobatrachonema, M. hainanensis sp. nov., was described based on specimens collected in Amolops hainanensis (Boulenger) and Hylarana spinulosa (Smith) (Amphibia: Anura) from Hainan Island, China. The large ribosomal DNA (28S) and internal transcribed spacer (ITS1-5.8S-ITS2) were also sequenced for molecular identification and phylogenetic study. Phylogenetic analyses using maximum likelihood (ML) inference and Bayesian inference (BI) based on 28S and ITS1 sequence data, respectively, supported that Megalobatrachonema is a member of the family Kathlaniidae. In addition, the genetic comparison and phylogenetic results based on ITS1 sequence data also supported that the genus Chabaudgolvania should be considered as a synonym of Megalobatrachonema.
Rabies is one of the major public health problems in China, and the mortality rate of rabies remains the highest among all notifiable infectious diseases. A meta-analysis was conducted to investigate the post-exposure prophylaxis (PEP) vaccination rate and risk factors for human rabies in mainland China. The PubMed, Web of Science, Chinese National Knowledge Infrastructure, Chinese Science and Technology Periodical and Wanfang databases were searched for articles on rabies vaccination status (published between 2007 and 2017). In total, 10 174 human rabies cases from 136 studies were included in this meta-analysis. Approximately 97.2% (95% confidence interval (CI) 95.1–98.7%) of rabies cases occurred in rural areas and 72.6% (95% CI 70.0–75.1%) occurred in farmers. Overall, the vaccination rate in the reported human rabies cases was 15.4% (95% CI 13.7–17.4%). However, among vaccinated individuals, 85.5% (95% CI 79.8%–83.4%) did not complete the vaccination regimen. In a subgroup analysis, the PEP vaccination rate in the eastern region (18.8%, 95% CI 15.9–22.1%) was higher than that in the western region (13.3%, 95% CI 11.1–15.8%) and this rate decreased after 2007. Approximately 68.9% (95% CI 63.6–73.8%) of rabies cases experienced category-III exposures, but their PEP vaccination rate was 27.0% (95% CI 14.4–44.9%) and only 6.1% (95% CI 4.4–8.4%) received rabies immunoglobulin. Together, these results suggested that the PEP vaccination rate among human rabies cases was low in mainland China. Therefore, standardised treatment and vaccination programs of dog bites need to be further strengthened, particularly in rural areas.
where Ω is a bounded smooth domain in ℝN (N ≥ 1), α ≥ 2 and θ is a parameter. Under the assumption that g(x, u) is sublinear near the origin with respect to u, we study the effect of the perturbation term h(x, u), which may break the symmetry of the associated energy functional. With the aid of critical point theory and the truncation method, we show that this system possesses multiple small negative energy solutions.