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Severe phase coarsening and separation in Sn–Bi alloys have brought increasing reliability concern in microelectronic packages. In this study, a phase field model is developed to simulate the microstructural evolution and evaluate the change in macroscopic physical properties of the flip chip Cu/Sn58Bi/Cu joint under the conditions of isothermal aging, as well as the coupled loads of elastic stress and electric current stressing. Results show that large-sized Bi-rich phase particles grow up at the expense of small-sized ones. Under the coupled loads, Bi atoms migrate along the electron flow direction, consequently Bi-rich phase segregates to form a Bi-rich phase layer at the anode. The current crowding ratio in the solder decreases rapidly first and then fluctuates slightly with time. Current density and von Mises stress exhibit inhomogeneous distribution, and both of them are higher in the Sn-rich phase than in the Bi-rich phase. Electric current transfers through the Sn-rich phase and detours the Bi-rich phase. As time proceeds, the resistance of the solder joint increases, and the average von Mises stress of the solder joint decreases. The Bi-rich phase coarsens much faster under the coupled loads than under the conditions of isothermal aging.
Research has demonstrated that trusting belief in one's ability is critical to coproducer selection; however, the importance of trusting belief in dedication has been ignored. This study aims to explore how reputation (i.e., word-of-mouth, certification, and recommendation) affects trusting belief in a potential coproducer's ability and dedication and examines its mediating effects in coproducing with a potential partner.
Empirical results show significant mediating effects of trusting belief in a potential coproducer's ability from certification, word-of-mouth, and recommendation, which in turn motivate coproduction, whereas certification leads to the motivation for coproduction through trusting belief in a potential coproducer's dedication. The findings refer to a unitary acceptance of ability but a divergent recognition of dedication. The focal party may regard certification as factual without personal distortion, while the recommendation is an evaluation worth considering. In considering dedication, the focal party may be unable to assess the extent of distortion from second-hand information (e.g., word-of-mouth).
Existing data on folate status and hepatocellular carcinoma (HCC) prognosis are scarce. We prospectively examined whether serum folate concentrations at diagnosis were associated with liver cancer-specific survival (LCSS) and overall survival (OS) among 982 patients with newly diagnosed, previously untreated HCC, who were enrolled in the Guangdong Liver Cancer Cohort (GLCC) study between September 2013 and February 2017. Serum folate concentrations were measured using chemiluminescent microparticle immunoassay. Cox proportional hazards models were performed to estimate hazard ratios (HR) and 95 % CI by sex-specific quartile of serum folate. Compared with patients in the third quartile of serum folate, patients in the lowest quartile had significantly inferior LCSS (HR = 1·48; 95 % CI 1·05, 2·09) and OS (HR = 1·43; 95 % CI 1·03, 1·99) after adjustment for non-clinical and clinical prognostic factors. The associations were not significantly modified by sex, age at diagnosis, alcohol drinking status and Barcelona Clinic Liver Cancer (BCLC) stage. However, there were statistically significant interactions on both multiplicative and additive scale between serum folate and C-reactive protein (CRP) levels or smoking status and the associations of lower serum folate with worse LCSS and OS were only evident among patients with CRP > 3·0 mg/l or current smokers. An inverse association with LCSS were also observed among patients with liver damage score ≥3. These results suggest that lower serum folate concentrations at diagnosis are independently associated with worse HCC survival, most prominently among patients with systemic inflammation and current smokers. A future trial of folate supplementation seems to be promising in HCC patients with lower folate status.
Electrical distribution equipment inspection is crucial for the electric power industry. With the rapid increase in the number of electrical distribution rooms, an unattended inspection method, for example, autonomous inspection robot, is eagerly desired by the industry to make up for the deficiencies of traditional manual inspection in effectiveness and validity. Existing inspection robots designed for indoor substations are generally lack of practicality, due to the factors such as inspection requirements and robot weight. To bridge the gap between prototype and practicality, in this work, we design the first completely autonomous robotic system, LongSword, which provides a satisfying technical solution for equipment inspection with an optical zoom camera, a thermal imaging camera or a partial discharge detector. Firstly, we design a novel and flexible hardware architecture which allows the robot to move, lift, and rotate in the station to reach any desired position. Secondly, we develop an intelligent software framework which consists of several modules to achieve accurate equipment recognition and reliable failure diagnosis. Thirdly, we achieve an apposite integration of the existing technologies to implement an applicable robotic system that can fulfill the requirements of indoor equipment inspection. There are over 200 LongSwords currently serving about 160 electrical distribution rooms, some of which have been working for more than 1 year. The average precision of device status recognition is up to 99.70%, and the average inspection time of a single device is as short as 13.5 s. The feedback from workers shows that LongSword can significantly improve the efficiency and reliability of equipment inspection, which accelerates the process of setting up unmanned stations.
Since the late 1990s, hand, foot and mouth disease (HFMD) has become a common health problem that mostly affects children and infants in Southeast and East Asia. Global climate change is considered to be one of the major risk factors for HFMD. This study aimed to assess the correlation between meteorological factors and HFMD in the Asia-Pacific region. PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Wanfang Data and Weipu Database were searched to identify relevant articles published before May 2018. Data were collected and analysed using R software. We searched 2397 articles and identified 51 eligible papers in this study. The present study included eight meteorological factors; mean temperature, mean highest temperature, mean lowest temperature, rainfall, relative humidity and hours of sunshine were positively correlated with HFMD, with correlation coefficients (CORs) of 0.52 (95% confidence interval (CI) 0.42–0.60), 0.43 (95% CI 0.23–0.59), 0.43 (95% CI 0.23–0.60), 0.27 (95% CI 0.19–0.35), 0.19 (95% CI 0.02–0.35) and 0.19 (95% CI 0.11–0.27), respectively. There were sufficient data to support a negative correlation between mean pressure and HFMD (COR = −0.51, 95% CI −0.63 to −0.36). There was no notable correlation with wind speed (COR = 0.10, 95% CI −0.03 to 0.23). Our findings suggest that meteorological factors affect the incidence of HFMD to a certain extent.
Owing to lack of a definitive correlation between carbon supports and catalytic activity of single-atom Fe-active sites, rational design and preparation of single-atom Fe catalysts have so far been elusive. Herein we designed and prepared one-dimensional core–shell nanostructured single-atom Fe catalysts, in which carbon nanofibers and carbon nanotubes with different crystallinities and electrical conductivities were used as supports to host single-atom Fe-active sites. It was found that the carbon supports with higher electrical conductivity accelerate charge transfer and enhance the oxygen reduction reaction (ORR) activity of single-atom Fe-active sites as well as the ORR durability of the final catalyst.
An H∞ controller combined with an Artificial Potential Field Method (APFM) was applied to seabed navigation for Autonomous Underwater Vehicles (AUVs), aimed particularly at obstacle avoidance and bottom-following operations in the vertical plane. Depth control and altitude control prevented the AUV from colliding with the sea bottom or with obstacles and prevented the AUV from diving beyond its maximum depth limit when bottom following. Simulation and laboratory trials with various seabed contours indicated that with the H∞ controller, the AUV was able to safely reach appointed destinations without collisions. Tests also showed that the H∞ controller was robust and suppressed interference, hence ensuring the precision of its navigation control. The proposed H∞ controller combined with the APFM has thus been proved to be both feasible and effective.
There are abundant data on secular trends in BMI; however, information on the change in subcutaneous fat is limited. The present study examined the trends in the prevalence of elevated skinfold thickness among children and adolescents over the past 19 years (1995–2014) in Shandong Province, China.
Data for the study were obtained from two cross-sectional surveys of schoolchildren carried out in 1995 and 2014. Triceps and subscapular skinfold thicknesses (SFT) of all participants were measured. The sum of triceps and subscapular SFT (SSFT) was applied. Children and adolescents with SSFT above or equal to the national age- and sex-specific 85th percentile were defined as ‘high SFT’.
Shandong Province, China.
A total of 16 917 students aged 7–18 years were included.
For both boys and girls, an increasing trend in ‘high SFT’ was observed between 1995 and 2014. The overall prevalence of ‘high SFT’ increased from 10·31 % for boys and 13·40 % for girls in 1995 to 33·94 % for boys and 29·30 % for girls in 2014 (P<0·01).
There are more children and adolescents with very high levels of SFT. These trends describe very unfavourable changes in the body composition and should give cause for concern.
The development of electrocatalysts with high activity and low cost has attracted growing attentions in recent years. Herein, we reported the Mn-doped CoP nanosheet arrays on flexible activated carbon cloth (Mn–CoP/CC) for the effective oxygen evolution reaction (OER) at low overpotential and high current density. Due to the novel 3D nanostructures of the carbon cloth and doping effect of the Mn element, the Mn doped CoP/CC electrode delivered the best overpotential of 317 mV for water splitting with the current density of 10 mA/cm2, a Tafel slope of ∼65.1 mV/dec, and excellent stability over 16 h in 1.0 mol/L KOH, which is superior or comparable to the most of the reported cobalt-based catalysts. Thus outstanding electrocatalytic performance originates from the Mn doping effect, which resulted in increased surface area and fast charge-transfer. It is believed that these findings would help us to develop high effective and stable electrocatalysts for water splitting.
Three-dimensional nitrogen-doped graphene frameworks (3DNGFs) hold great promise in the application of supercapacitors for the advantages of superior conductivity, well-connected porous structure, and additional N-containing active sites for charge storage. Nevertheless, the developed techniques for preparing 3DNGFs always suffer from the drawbacks of high cost or complex processes for large-scale application. Herein, a new and cost-effective method has been developed to massively prepare monolithic 3DNGFs by a simple and scalable electrochemical oxidation process. Benefiting from the enhanced electrical conductivity, the increase in the pore volume for fast diffusion increased the electrode–electrolyte contact area and additional active sites resulting from the incorporation of nitrogen species, the 3DNGFs showed a high specific capacitance of 2250.3 mF/cm2 at 4 mA/cm2, with good rate capability. Furthermore, this 3DNGFs electrode also owns an excellent long-term cycling stability that can retain more than 97.5% of its original capacitance after 10,000 cycles.
To develop a theoretical model explaining the longitudinal changes in the caregiving process for family caregivers of persons with mild cognitive impairment (MCI) in Taiwan.
A longitudinal, grounded theory approach using in-depth face-to-face interviews and an open-ended interview guide. We conducted 42 interviews over a two-year period; each participant was interviewed at least once every six months. All participants were interviewed in their home. The participants total of 13 family caregivers of persons with MCI.
One core theme emerged: “protective preparation.” This reflected the family caregiving process of preparation for a further decline in cognitive function, and protection from the impact of low self-esteem, accidents, and symptoms of comorbidities for the family member with MCI. Protective preparation contained three components: ambivalent normalization, vigilant preparation, and protective management.
Interventions to help family caregivers manage the changes in persons with MCI can reduce caregiver burden. Our findings could provide a knowledge base for use by healthcare providers to develop and implement strategies to reduce caregiver burden for family caregivers of persons with MCI.
Background: Good primary health care can enhance national health status at relatively low cost. The barefoot doctor model in China was once considered to have been a successful health care policy. It was a model which was followed by other low-developed or developing countries. In recent decades, the Chinese government promulgated a number of new policies and health reforms to improve its health care system. Aim: This paper aimed to highlight the great significance of primary health care and appeal to the policymakers to change the priority to primary health care in order to be able to guarantee universal health care for the whole nation at least at primary care level. Method: This study discussed Chinese primary health care by reviewing its history and development. Finding: Chinese government’s efforts do not seem to be leading to a completely successful outcome for all the people of China as a result of the substantial imbalance of investments between tertiary level hospitals and grass-root level health care institutions. The government appears to have neglected the importance of primary health care in the implementation of health systems and resources.
Efforts to extract weak geomagnetic excursion signals from Chinese loess-paleosol 10Be have generally been unsuccessful due to the complexities of its accumulation, because the geomagnetic and climate (precipitation and dust) signals contained in loess-paleosol sequence are tightly overprinted. Here, we present a reconstruction of geomagnetic relative paleointensities for the past 130 kyr from 10Be records in 2 Chinese loess-paleosol sections using a correction based on the correlation of 10Be with magnetic susceptibility (SUS) to remove the climatic contamination. Both these records reveal the Laschamp and Blake events, which lie in the loess and paleosol (L1SS1 and S1SS3) horizons corresponding to mid-MIS 3 and 5e, respectively. The good agreement between our results and other geomagnetic intensities reconstructions from Atlantic and Pacific sediments indicates that our method is robust. Our study suggests the potential application of loess-paleosol 10Be for reconstructing geomagnetic intensity variations spanning the whole Quaternary.
Traditional near-field antenna measurements use the sampling theorem to reconstruct the antenna pattern perfectly. However, a large number of measurement points are required for this approach. To address this problem, in this study, we propose a technique to accelerate the near-field antenna measurement, which is achieved by sparse E-field sampling in the region where the E-field changes smoothly and dense sampling in the region where the field changes rapidly. Further, our approach ensures robustness of measurement; the E-field information need not be known before carrying out measurements. Our experimental results demonstrate that our technique can reduce the number of measuring points by at least 64.9% when measuring two different patterns (15-GHz horn antenna with θ = 0° and 10°).
A new quad-band bandpass filter for Global System for Mobile Communications, Wireless Local Area Network, and Worldwide Interoperability for Microwave Access is designed and fabricated using the stub-loaded resonator (SLR) technology without complex fabrication process, such as via-hole or multi-layer substrate. Owing to the embedded SLR, the proposed quad-mode resonator is compact. Equivalent circuits of the proposed quad-mode resonator are analyzed in detail, and high design freedom is shown because of shifting the passband frequencies individually. Good passband selectivity and isolation of the each passband at 1.8, 2.4, 3.5, and 5.2 GHz can be well achieved due to the transmission zeros appeared near the each passband edges. Experimental results show good agreement with the simulated results.
This study has extended existing research on CEO power, pay structure, and firm performance, offering models based mainly on agency theory and managerial power theory, and testing hypotheses using data from 112 companies across a five-year span (2001–2005) in computer-related industry groups in the United States. The results indicated that power from executive directorship positively impacts a firm's return on assets and return on equity, and that CEO power from duality negatively impacts CEO long-term pay and total pay, while CEO power from tenure positively impacts CEO long-term pay and pay leverage, and composite power negatively impacts short-term pay. Evidence for CEO pay as a mediator between CEO power and firm performance revealed that CEO short-term pay positively impacts a firm's return on assets and international performance but negatively impacts its market value, regardless of which source of power is being controlled. CEO total pay positively impacts a firm's return on assets and international performance, with power from CEO duality, directorship, or composite power being controlled. Hence, and in general, CEO pay fails to significantly mediate the relationships between CEO power and firm performance. The contributions include a multiple-perspective study of CEO power, compensation, and firm performance to comprehensively discover each of their respective relationships. This study has further extended the debate over agency perspectives with stewardship perspectives to fill knowledge and theoretical gaps. Thus, evidence-based findings provide boards of directors with practical knowledge for sound governance with another avenue for future research in corporate governance.
Congenital anomalies of the coronary arteries are present in 0.2–1.4% of the general population. These anomalies represent one of the most confusing issues in the field of cardiology and challenges for interventional cardiologists and cardiac surgeons if the anomalies are unrecognised. Double right coronary artery is one of the rarest coronary arteries. Previously, the probability of developing atherosclerotic changes in patients with a double right coronary artery was considered to be equal to that in those without it. In reality, however, a high prevalence of atherosclerotic coronary artery disease was found in patients with a double right coronary artery originating from a single ostium after our comprehensive literature search through the PubMed database. Owing to the fact that double right coronary artery is both a congenital and potentially atherosclerotic coronary artery disease at diagnosis, coronary intervention or cardiac operation is more complicated than previously believed. Individuals with a double right coronary artery may be unaware of its presence until an accidental finding during coronary angiography or cardiac operation and are at risk for unsuspected complications of atherosclerotic coronary artery disease or during cardiac operation. Therefore, it is important to obtain information on the anatomic variants of this congenital coronary anomaly in patients who are undergoing either coronary intervention, aortic root operation or myocardial revascularisation. To our knowledge, this is the first comprehensive article to discuss the anomalies and their clinical implications.
Two sets of reciprocal introgression lines (ILs) and a population of recombinant inbred lines (RILs) derived from the cross between japonica cultivar Xiushui09 and indica breeding line IR2061-520-6-9 (abbreviated as IR2061) were used to identify QTL for heading date (HD). Phenotyping was conducted in Hainan Island for two winter seasons (2007 and 2009). Nine QTLs were detected in the ILs with Xiushui09 background (XS-ILs), and four of which were repeatedly mapped across 2 years. Five QTLs were identified in the ILs with IR2061 background (IR-ILs), and three of which were commonly detected in 2 years. All commonly detected QTL had the same direction of gene effect. Seven QTL for HD were identified in the RILs in 2009. Only three (25%) QTLs were commonly detected using all the three populations (XS-ILs, IR-ILs and RILs). The number of commonly identified QTLs among populations was related to degree of similarity of their genetic backgrounds, suggesting that the genetic background effect is important for detecting HD QTL. QHd7 and QHd10b stably expressed in different populations and across years thus would be exploited in rice breeding programme. Moreover, lines with both of QHd7 and QHd10b resulted in at least 3 days earlier than lines with only one of them QTL, showing evident pyramiding effect.
Despite gradual understanding of the multidimensional health consequences
of betel-quid chewing, information on the effects of dependent use is
To investigate the 12-month prevalence patterns of betel-quid dependence
in six Asian populations and the impact of this dependence on oral
potentially malignant disorders (OPMD).
A multistage random sample of 8922 participants was recruited from
Taiwan, mainland China, Indonesia, Malaysia, Sri Lanka and Nepal.
Participants were evaluated for betel-quid dependency using DSM-IV and
ICD-10 criteria and assessed clinically for oral mucosal lesions.
The 12-month prevalence of dependence was 2.8-39.2% across the six Asian
samples, and 20.9-99.6% of those who chewed betel-quid were betel-quid
dependent. Men dominated the prevalence among the east Asian samples and
women dominated the prevalence in south-east Asian samples. ‘Time spent
chewing’ and ‘craving’ were the central dependence domains endorsed by
the Chinese and southern/south-east Asian samples respectively, whereas
the Nepalese samples endorsed ‘tolerance’ and ‘withdrawal’. Dependency
was linked to age, gender, schooling years, drinking, smoking,
tobacco-added betel-quid use and environmental accessibility of
betel-quid. Compared with non-users, those with betel-quid dependency had
higher pre-neoplastic risks (adjusted odds ratios 8.0-51.3) than people
with non-dependent betel-quid use (adjusted odds ratio 4.5-5.9) in the
six Asian populations.
By elucidating differences in domain-level symptoms of betel-quid
dependency and individual and environmental factors, this study draws
attention to the population-level psychiatric problems of betel-quid
chewing that undermine health consequences for OPMD in six Asian