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We demonstrate an all-optical method for controlling the transverse motion of an ionization injected electron beam in a laser plasma accelerator by using the transversely asymmetrical plasma wakefield. The laser focus shape can control the distribution of a transversal wakefield. When the laser focus shape is changed from circular to slanted elliptical in the experiment, the electron beam profiles change from an ellipse to three typical shapes. The three-dimensional particle-in-cell simulation result agrees well with the experiment, and it shows that the trajectories of these accelerated electrons change from undulating to helical. Such an all-optical method could be useful for convenient control of the transverse motion of an electron beam, which results in synchrotron radiation from orbit angular momentum.
To measure the associations of sociodemographic and behavioural factors with fruit and vegetable consumption among adults in China.
A cross-sectional study.
A 2015 wave of the China Health and Nutrition Survey.
Totally, 11 910 adults aged 18 to 64 years.
Adjusted log binomial regression analyses showed that adults with higher income levels had higher fruit intake than those with low income levels (medium income group, risk ratio (RR): 1·28; 95 % CI: 1·16, 1·41; high income group, RR: 1·58; 95 % CI: 1·43, 1·74). Current smokers had lower fruit intake than non-smokers (RR: 0·86; 95 % CI: 0·77, 0·96). Adults living in southern China had higher vegetable intake (RR: 1·88; 95 % CI: 1·76, 2·01) but lower fruit intake (RR: 0·85; 95 % CI: 0·79, 0·91) than adults in northern China. With increasing age, adults had higher fruit intake (50–64 years, RR: 1·20; 95 % CI: 1·09, 1·33; reference category 18–34 years) and higher vegetable intake (35–49 years, RR: 1·13; 95 % CI: 1·05, 1·22; 50–64 years, RR: 1·22; 95 % CI: 1·13, 1·31).
Our findings identify a range of sociodemographic and behavioural factors associated with fruit and vegetable consumption among Chinese adults. They also point to the need for public health nutrition interventions for socially disadvantaged populations in China.
Octapyrgites elongatus n. gen. n. sp., a relatively rare, tetraradial olivooid (Cnidaria, Medusozoa), is described from Bed 5 of the Yanjiahe Formation (Cambrian Stage 2) near Yichang, China. Although similar to Olivooides and Quadrapyrgites from the Fortunian Stage in consisting of a partially corrugated (longitudinal) periderm with a quadrate (transverse) apical portion and V-shaped apertural lobes, O. elongatus is substantially larger than other olivooids. The elongate apical region of O. elongatus is similar to four-sided Anaconularia anomala (Barrande, 1867), though with a flat tip that may have been an adaption for a sessile mode of life. As in other olivooids, embryonic development in O. elongatus may have been direct. Last, the paucity of olivooids and the absence of pentaradial cnidarians and carinachitids in Cambrian Stage 2 indicate a marked decline in the disparity of cnidarians near the Fortunian–Cambrian Age 2 boundary, when by contrast bilaterians underwent rapid diversification.
The frequency division multiple access (FDMA) strategy used in GLONASS causes inter-frequency phase bias (IFPB) and inter-frequency code bias (IFCB) between receivers from different manufacturers. The existence of IFPB and IFCB significantly increases the difficulties of fixing GLONASS ambiguity and limits the accuracy and reliability of GLONASS positioning. Moreover, the initial value of IFPB and IFCB may be unavailable or unreliable with the increasing number of receivers from different manufacturers in recent years. In this study, a real-time and reliable calibration algorithm of IFPB and IFCB based on multi-GNSS assistance is proposed by providing a fixed solution. Real-time IFPB rate and IFCB can be obtained using this algorithm without the initial IFPB and IFCB. The IFPB rate for all GLONASS satellites and IFCB for each GLONASS satellite are estimated due to different characteristics of IFPB and IFCB. IFPB calibration can be divided into constant and real-time IFPB calibrations to meet the different positioning requirements. Results show that constant IFPB rate has only 2 mm difference from the mean value of real-time IFPB rate. The IFPB rate and IFCB estimated by this algorithm have excellent stability, and the change in reference satellite cannot affect the results of IFPB rate and the stability of IFCB. The centimetre-level positioning results can be obtained using two calibration methods, and the positioning results with real-time calibration method are 10%–20% better than those with the constant calibration method. Under satellite-deprived environments, the improvements of multi-GNSS positioning accuracy with constant inter-frequency bias calibration gradually increase as the satellite cut-off elevation angle increases compared with GPS/BDS, which can reach up to 0·9 cm in the vertical direction.
Welding was successfully used in the fabrication of low pressure steam turbine rotors for nuclear power plants. In this paper, the local brittle zone of the welded joint in NiCrMoV steel with heavy section was investigated by cross-zone fracture toughness test and the effect of martensite–austenite constituent in the simulated reheated zone of welds with different second peak temperature on toughness was analyzed. The results showed that the crack propagated in unstable manner in the reheated zone of welds where the martensite–austenite constituent promoted the initiation and propagation of the crack. The fine structure of martensite–austenite constituent contained retained austenite, martensite, and martensite–austenite mixture microstructure. The impact toughness deteriorated drastically in the incomplete phase transition zone for the simulated reheated zone of welds related to the formation of mixture microstructure in which large blocky martensite–austenite constituent at prior austenite grain boundaries and inside the grains were distributed in the shape of network.
We evaluate the relative importance of climate change, fluvial dynamics, and anthropogenic environmental modification in forming the Holocene sedimentary record of the Luoyang Basin, a tributary drainage basin of the Yellow River, located in western Henan Province, China. Our 2011 fieldwork south of the Erlitou site in the Luoyang Basin indicates that an unconformity dating to ca. AD 1100 is roughly coincident with a major southward shift in the lower course of the Yellow River. In AD 1128, the governor of Kaifeng breached the dikes of the Yellow River to impede an advancing army, causing the Yellow River to flow south out to the Yellow Sea. We argue that the dike breach not only changed the fluvial dynamics of the Yellow River but also switched the rivers in the Luoyang Basin from an aggrading to an incising system. The resumption of sedimentation in the Luoyang Basin is roughly coincident with the next major shift of the Yellow River’s main course northward to the Bohai Sea in AD 1855. The unconformity found in the Luoyang Basin may be a legacy of historically contingent human agency rather than climatic shifts or gradual environmental modification.
Percutaneous transcatheter occlusion has benefited thousands of patients suffering from patent foramen ovale and atrial septal defect. However, no general agreement has been reached on the superiority among occluders. Thus, a meta-analysis between the two most commonly adopted types of occluders was conducted.
The literature review has identified relevant studies up to May, 2011 in the databases of PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, and World Health Organization clinical trials registry centre. Meta-analysis was performed in a fixed/random effects model using Revman 5.1.1. Information on complications and outcomes was extracted.
Analysis from included studies reports an outcome in favour of the Amplatzer. The Amplatzer has proven its superiority in efficacy with a significantly lower risk of early (95% confidence interval = 0.09–0.34) and long-term (95% confidence interval = 0.14–0.97) residual shunt rate for atrial septal defect occlusion, although no significant difference in performance has been reported for patent foramen ovale. In addition, the Amplatzer has also remarkably reduced the risk of embolisation by the device (95% confidence interval = 0.07–0.45) for atrial septal defect and new-set atrial fibrillation (95% confidence interval = 0.18–0.48) for patent foramen ovale. On evaluation of recurrent thrombotic events, it was found that the Amplatzer greatly lowered the rate of thrombus formation on the device (95% confidence interval = 0.02–0.21) for patent foramen ovale; however, no statistical difference was found on atrial septal defect evaluation. However, the result indicated no statistically significant difference between the two kinds of occluders in stroke and transient ischaemic attack of patent foramen ovale.
The meta-analysis has proven the Amplatzer to be the superior occluder, serving better prognosis with more fluent procedure and less complications.
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