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A dynamic collision avoidance algorithm via layered artificial potential field with collision cone (LAPF-CC) is proposed to overcome the shortcomings of the traditional artificial potential field method in dynamic collision avoidance. In order to reduce invalid actions for collision avoidance, the potential field is divided into four layers, and a collision cone with risk detection function is introduced. Relative distance and relative velocity are used as variables to establish the risk of collision, and a torque named ‘speed torque’ is constructed. Speed torque, attractive force and repulsive force work together to change the speed and heading of the unmanned surface vehicle (USV). Driving force and torque are controlled separately, which makes it possible for the LAPF-CC algorithm to be used for real-time collision avoidance control of underactuated USVs. Simulation results show that the LAPF-CC algorithm performs well in dynamic collision avoidance.
No risk assessment tools for the efficacy of folic acid treatment for hyperhomocysteinaemia (HHcy) have been developed. We aimed to use two common genetic risk score (GRS) methods to construct prediction models for the efficacy of folic acid therapy on HHcy, and the best gene–environment prediction model was screened out. A prospective cohort study enrolling 638 HHcy patients was performed. We used a logistic regression model to estimate the associations of two GRS methods with the efficacy. Performances were compared using area under the receiver operating characteristic curve (AUC). The simple count genetic risk score (SC-GRS) and weighted genetic risk score (wGRS) were found to be independently associated with the efficacy of folic acid treatment for HHcy. Using the SC-GRS, per risk allele increased with a 1·46-fold increased failure risk (P < 0·001) after adjustment for traditional risk factors, including age, sex, BMI, smoking, alcohol consumption, history of diabetes, history of hypertension, history of hyperlipidaemia, history of stroke and history of CHD. When used the wGRS, the association was strengthened (OR = 2·08, P < 0·001). Addition of the SC-GRS and wGRS to the traditional risk model significantly improved the predictive ability by AUC (0·859). A precise gene–environment predictive model with good performance was developed for predicting the treatment failure rate of folic acid therapy for HHcy.
Dongxiang common wild rice (Oryza rufipogon Griff., DXWR) is an important genetic resource for the improvement of cultivated rice. For the past three decades, great achievements have been made in the field of molecular marker development. Although structural variations (SVs) had been studied between DXWR and Nipponbare (Oryza sativa L. ssp. japonica), the development and application of SV markers in DXWR has not been reported. In this study, based on the genome-wide SV loci, we developed and synthesized a total of 195 SV markers that were evenly distributed across the 12 rice chromosomes. Then, these markers were tested for their stabilities and polymorphisms. Of these 195 markers, 147 (75.4%) were successfully amplified and displayed abundant polymorphisms between DXWR and Nipponbare. Meanwhile, through the genotyping of 20 rice varieties from 13 countries and areas, we concluded that these SV markers have a wide application prospect in the analysis of cultivated rice. Therefore, these molecular markers greatly enrich the number of markers available for DXWR, which will facilitate genomic research and molecular breeding for this important and endangered germplasm resource.
Flexibility is a key parameter of device mechanical robustness. The most profound challenge for the realization of flexible electronics is associated with the relatively low flexibility of power sources. In this article, two kinds of energy applications, which have gained increasing attention in the field of flexibility in recent years, are introduced: the lithium-ion batteries and the supercapacitors. We overview the latest progresses in flexible materials and manufacturing technology. The performances of the energy devices based on flexible materials are introduced. The advantages and disadvantages of different manufacturing processes are discussed systematically. We then focus on current technical difficulties and future prospects of research in flexibility.
The aim of this study is to analyse the efficacy rate of folate for the treatment of hyperhomocysteinaemia (HHcy) and to explore how folate metabolism-related gene polymorphisms change its efficacy. This study also explored the effects of gene–gene and gene–environment interactions on the efficacy of folate. A prospective cohort study enrolling HHcy patients was performed. The subjects were treated with oral folate (5 mg/d) for 90 d. We analysed the efficacy rate of folate for the treatment of HHcy by measuring homocysteine (Hcy) levels after treatment. Unconditioned logistic regression was conducted to analyse the association between SNP and the efficacy of folic acid therapy for HHcy. The efficacy rate of folate therapy for HHcy was 56·41 %. The MTHFR rs1801133 CT genotype, TT genotype and T allele; the MTHFR rs1801131 AC genotype, CC genotype and C allele; the MTRR rs1801394 GA genotype, GG genotype and G allele; and the MTRR rs162036 AG genotype and AG+GG genotypes were associated with the efficacy of folic acid therapy for HHcy (P<0·05). No association was seen between other SNP and the efficacy of folic acid. The optimal model of gene–gene interactions was a two-factor interaction model including rs1801133 and rs1801394. The optimal model of gene–environment interaction was a three-factor interaction model including history of hypertension, history of CHD and rs1801133. Folate supplementation can effectively decrease Hcy level. However, almost half of HHcy patients failed to reach the normal range. The efficacy of folate therapy may be genetically regulated.
The Be-based materials with many particular properties lead to an important research subject. The investigation progresses in the fabrication technologies are introduced here, including main three kinds of Be-based materials, such as Be–Cu capsule,
ablator and high-purity Be material. Compared with the pioneer workgroup on Be-based materials, the differences in Be–Cu target fabrication were described, and a grain refinement technique by an active hydrogen reaction for Be coating was proposed uniquely.
coatings were first prepared by the DC reactive magnetron sputtering with a high deposition rate
. Pure polycrystalline
films with uniform microstructures, smooth surface, high density
and good optical transparency were fabricated. In addition, the high-purity Be materials with metal impurities in a ppm magnitude were fabricated by the pyrolysis of organometallic Be.
To better stabilize the hydrogen-terminated surface, a diamond based metal-insulator-semiconductor field-effect transistor with Zr-Si-N dielectric layer has been investigated. On the diamond epitaxial layer grown by microwave plasma chemical vapor deposition system, Pd films were patterned as the source and drain electrodes by photolithography and electron beam evaporation methods. Then, a Zr-Si-N dielectric layer and W metal film were fabricated as the gate structure by radio frequency magnetron sputtering technique. The device illustrates p-type depletion mode, in which the threshold voltage, maximum transconductance, drain current maximum, capacitance and dielectric constant were calculated to be 3.0V, 1.27mS/mm, -5.16 mA/mm, 0.275μF/cm2 and 7.8, respectively. The result suggest that Zr-Si-N dielectric layer is shown to have the ability to protect the two-dimensional hole gas.
Upon a set of backward orthogonal polynomials, we propose a novel multi-step numerical scheme for solving the decoupled forward-backward stochastic differential equations (FBSDEs). Under Lipschtiz conditions on the coefficients of the FBSDEs, we first get a general error estimate result which implies zero-stability of the proposed scheme, and then we further prove that the convergence rate of the scheme can be of high order for Markovian FBSDEs. Some numerical experiments are presented to demonstrate the accuracy of the proposed multi-step scheme and to numerically verify the theoretical results.
In this paper, a new numerical method for solving the decoupled forward-backward stochastic differential equations (FBSDEs) is proposed based on some specially derived reference equations. We rigorously analyze errors of the proposed method under general situations. Then we present error estimates for each of the specific cases when some classical numerical schemes for solving the forward SDE are taken in the method; in particular, we prove that the proposed method is second-order accurate if used together with the order-2.0 weak Taylor scheme for the SDE. Some examples are also given to numerically demonstrate the accuracy of the proposed method and verify the theoretical results.
Taking the advantage of nanomaterials to protect the environment and avoiding the side effect need a fundamental understanding of the growth mechanism of the nanomaterials. Here, the van der Waals interaction between a nanoparticle and a nanotube in the oriented-attachment growth of nanotubes is quantitatively evaluated for the first time. In particular, the correlation between van der Waals interaction and the growth parameters is investigated in depth. Our work opens up the opportunity of studying the important interparticle interactions in the oriented attachment growth of nanotubes.
Females in most populations of chiru or Tibetan antelope Pantholops hodgsonii migrate each year up to 350 km to summer calving grounds, and these migrations characterize the Tibet/Qinghai Plateau. We studied the migratory chiru population at the Ullughusu calving grounds south-west of the Arjinshan Nature Reserve in Xinjiang, China. The 750–1,000 km2 of suitable habitat at Ullughusu is at 4,500–5,000 m with sparse vegetation. We used direct methods (block counts, vehicle and walking transects and radial point sampling) and an indirect method (pellet counts) during six summers to assess population density. We also witnessed and stopped two major poaching events, in 1998 and 1999 (103 and 909 carcasses, respectively). Surveys suggested a drop in population density from 1999 to 2000. Poaching was not seen during summer monitoring after 1999, and surveys in 2001 and 2006 suggest that the population density is stable or recovering. We compare the Ullughusu calving grounds with those in the western Kunlun and discuss possible routes for migrating females.
Neurenteric cysts are rare congenital epithelium-lined cysts of the central nervous system. They are found predominantly in the spinal cord, with lower incidence in the intracranial compartment, and may be associated with various other congenital spinal anomalies. Seven patients with symptomatic intraspinal neurenteric cysts are presented.
Materials and Methods:
Seven patients with intraspinal neurenteric cysts aged from nine months to ten years treated at this hospital from May 2000 to July 2006 were reviewed. The clinical manifestations, imaging and surgical findings of patients were analyzed retrospectively. All patients underwent operation. One patient's cervical neurenteric cyst was resected using the lateral cervical approach, and the other six resections were performed with posterior approach.
All seven patients presented with neurological involvement. One patient had an intramedullary cyst, while the other six cysts were situated ventrally. Three patients' cysts occurred in the cervical region, two in the cervicothoracic region, one in the thoracic region and one in the lumbar region. One patient had bony anomalies, and one had a lumbar posterior occult spinal dysraphism. Five patients' symptoms improved rapidly after surgery.
Intraspinal neurenteric cysts in children are rare and most occur ventral to the spinal cord. Magnetic resonance imaging (MRI) is the most effective imaging modality. Earlier diagnosis and surgical resection of spinal neurenteric cysts improves prognosis.
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