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Search Results: 1 - 10 of 38068 matches for " Qicai Lin "
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Influence of Dams on River Ecosystem and Its Countermeasures  [PDF]
Qicai Lin
Journal of Water Resource and Protection (JWARP) , 2011, DOI: 10.4236/jwarp.2011.31007
Abstract: Dam construction is an important engineering measure in dealing with the relationship between water and human being. However, with dam construction, some disadvantages to the river basin may be caused, including flow flux of downstream changed, flooded area reduced, river species and other organisms changed and substance sedimentation. Furthermore, it brings some diseases to human being and human residential areas reduced too. Based on the basic principles of ecohydralic engineering, some countermeasures to minimize the negative effects on rivers were put forward. They are reservoir ecological regulation, ecohydraulic engineering construction and comprehensive water pollution treatment.
Reflection of plane electromagnetic waves from the surface of a perfect conductor moving in an arbitrary direction
Qicai He,Yaoxiong Huang
Chinese Science Bulletin , 2000, DOI: 10.1007/BF02886213
Abstract: The reflection of plane electromagnetic waves (TE wave and TM wave) from a perfect conductor which moves in an arbitrary direction is investigated. Based on Maxwell’s equations and the boundary conditions for moving boundary, the relation between the field vectors of reflected and incident waves, and the reflection coefficient are derived. The energy balance between incident and reflected waves, the force exerted by electromagnetic waves to the moving conductor are also discussed and some new conclusions are suggested for notice.
Binaurality and azimuth tuning of neurons in the auditory cortex of the big brown bat
Junxian Shen,Qicai Chen
Chinese Science Bulletin , 2002, DOI: 10.1007/BF02907575
Abstract: By using a combined closed and free-field stimulation system, binaurality and azimuth tuning of the neurons in the auditory cortex of the big brown bat,Eptesicus fuscus, were studied. A variety of azimuth-tuning functions were demonstrated for the binaural neurons. The large majority of EE (contralateral and ipsilateral excitatory) neurons exhibited azimuth selectivity with the best azimuths (BA) at contralateral 30°–40°, some at ipsilateral 20°-40° and preferred azimuth ranges (PAR, response amplitude 75% of maximum) between 8° and 40°. Sound source azimuths strongly modulate spike counts with a mean modulation depth of 83.8% for EE neurons. EI (contralateral excitatory and ipsilateral inhibitory) neurons have simple azimuth tuning with BA located at contralateral 20°-40° and a broad PAR ranged from 30° to 55°. The present results suggest that azimuth-tuning characteristics of binaural neurons in the auditory cortex of the bat are of significance for acoustic behaviour.
Optimization Problems of Excess-of-Loss Reinsurance and Investment under the CEV Model
Qicai Li,Mengdi Gu
ISRN Mathematical Analysis , 2013, DOI: 10.1155/2013/383265
Abstract: We consider that the insurer purchases excess-of-loss reinsurance and invests its wealth in the constant elasticity of variance (CEV) stock market. We model risk process by Brownian motion with drift and study the optimization problem of maximizing the exponential utility of terminal wealth under the controls of excess-of-loss reinsurance and investment. Using stochastic control theory and power transformation technique, we obtain explicit expressions for the optimal polices and value function. We also show that the optimal excess-of-loss reinsurance is always better than optimal proportional reinsurance. Some numerical examples are given. 1. Introduction Many papers deal with optimal reinsurance or optimal investment issues for diffusion approximation risk models in the past ten years. In these papers, the insurer is allowed to take reinsurance and/or invest its capital in the Black-Scholes market. Some of the problems have been dealt with through stochastic control theory and related methodologies for finding the minimum probability of ruin or the maximum expected utility of terminal wealth. Browne [1] used a Brownian motion with a drift to describe the surplus of the insurer and found the optimal investment policy to maximize the expected exponential utility of terminal wealth. Later, Schmidli [2], Taksar and Markussen [3] considered the optimal reinsurance policy which minimizes the ruin probability of the cedent. Recently, much research on insurance optimization in the presence of both proportional reinsurance and investment has been done. Luo et al. [4] studied optimal proportional reinsurance and investment policy which minimizes the probability of ruin. Bai and Guo [5] investigated the problem of maximizing the expected exponential utility of terminal wealth with multiple risky assets and proportional reinsurance. For related works, see, for example, Promislow and Young [6], Liang and Guo [7] and references therein. The excess-of-loss reinsurance has also attracted interest among academia and practitioners. Asmussen et al. [8] studied a dynamic choice of excess-of-loss reinsurance retention level and the dividend distribution policy which maximizes the expected present value of the dividends in a diffusion model. Zhang et al. [9] considered the problem of minimizing the probability of ruin by controlling the combinational quota-share and excess-of-loss reinsurance strategy. Meng and Zhang [10] investigated optimal risk control for the excess-of-loss reinsurance policy which minimizes the probability of ruin. Bai and Guo [11] explored optimal
Binaurality and azimuth tuning of neurons in the auditory cortex of the big brown bat

Junxian Shen,Qicai Chen,

科学通报(英文版) , 2002,
Abstract: By using a combined closed and free-field stimulation system, binaurality and azimuth tuning of the neurons in the auditory cortex of the big brown bat, Eptesicus fuscus, were studied. A variety of azimuth-tuning functions were demonstrated for the binaural neurons. The large majority of EE (contralateral and ipsilateral excitatory) neurons exhibited azimuth selectivity with the best azimuths (BA) at contralateral 30(- 40(, some at ipsilateral 20(-40( and preferred azimuth ranges (PAR, response amplitude ≥75% of maximum) between 8( and 40(. Sound source azimuths strongly modulate spike counts with a mean modulation depth of 83.8% for EE neurons. EI (contralateral excitatory and ipsilateral inhibitory) neurons have simple azimuth tuning with BA located at contralateral 20(-40( and a broad PAR ranged from 30( to 55(. The present results suggest that azimuth-tuning characteristics of binaural neurons in the auditory cortex of the bat are of significance for acoustic behaviour.
Approximation Algorithms for the Connected Sensor Cover Problem
Lingxiao Huang,Jian Li,Qicai Shi
Computer Science , 2015,
Abstract: We study the minimum connected sensor cover problem (\mincsc) and the budgeted connected sensor cover (\bcsc) problem, both motivated by important applications in wireless sensor networks. In both problems, we are given a set of sensors and a set of target points in the Euclidean plane. In \mincsc, our goal is to find a set of sensors of minimum cardinality, such that all target points are covered, and all sensors can communicate with each other (i.e., the communication graph is connected). We obtain a constant factor approximation algorithm, assuming that the ratio between the sensor radius and communication radius is bounded. In \bcsc\ problem, our goal is to choose a set of $B$ sensors, such that the number of targets covered by the chosen sensors is maximized and the communication graph is connected. We also obtain a constant approximation under the same assumption.
Efficiency of Ferritin as an MRI Reporter Gene in NPC Cells Is Enhanced by Iron Supplementation
Yupeng Feng,Qicai Liu,Junfeng Zhu,Fukang Xie,Li Li
Journal of Biomedicine and Biotechnology , 2012, DOI: 10.1155/2012/434878
Abstract: Background. An emerging MRI reporter, ferritin heavy chain (FTH1), is recently applied to enhance the contrast and increase the sensitivity of MRI in the monitoring of solid tumors. However, FTH1-overexpression-related cytotoxicity is required to be explored. Methods. By using the Tet-Off system, FTH1 overexpression was semi-quantitativiely and dynamicly regulated by doxycycline in a NPC cell line. Effects of FTH1 overexpression on the proliferation, cytotoxicity, apoptosis and migration of NPC cells were investigated in vitro, and MR relaxation rate was measured in vitro and in vivo. Results. In vitro and in vivo overexpression of FTH1 significantly increased the transverse relaxivity (2), which could be enhanced by iron supplementation. In vitro, overexpression of FTH1 reduced cell growth and migration, which were not reduced by iron supplementation. Furthermore, cells were subcutaneously inoculated into the nude mice. Results showed FTH1 overexpression decreased tumor growth in the absence of iron supplementation but not in the presence of iron supplementation. Conclusion. To maximize 2 and minimize the potential adverse effects, supplementation of iron at appropriate dose is recommended during the application of FTH1 as a reporter gene in the monitoring of NPC by MRI.
Role of frequency band integration in sharpening frequency tunings of the inferior colliculus neurons in the big brown bat,Eptesicus fuscus
Feijian Wu,Qicai Chen,Philip H. S. Jen,Junxian Shen
Chinese Science Bulletin , 2004, DOI: 10.1007/BF03184032
Abstract: By means of a particular two-tone stimulation paradigm in combination of using a pair of electrodes for simultaneously recording from two inferior colliculus (IC) neurons, the currentin vivo study is undertaken to explore the role of frequency band integration (FBI) in sharpening of frequency tuning in the big brown bat,Eptesicus fuscus. Three major results are found: (1) The paired neurons correlated to FBI are located not only within the same frequency filter bandwidth (FFB), but also across different FFBs. The relations of their frequency tuning curves (FTCs) are mainly of two types: the flank-overlapped and overlaid patterns. (2) Although the sharpness of FTCs between paired neurons is mutual, the sharpening efficiency of neurons located within the same FFB is higher than that of neurons across FFBs, and the FTCs of neurons with the best frequencies (BF) of 20 –30 kHz are most strongly sharpened. (3) The strength of FBI is weak near the BF but gradually increased with frequencies away from the BF of sound stimuli. This suggests that the dynamical FBI of the IC neurons located within and across the FFBs might be involved in the formation of functional FFB structures.
A Pilot Study to Evaluate an Internet-Based Cervical Cancer Screening Model Based on Self-Sampling  [PDF]
Ruifang Wu, Xinfeng Qu, Hui Du, Zhihong Liu, Qicai Hu, Chun Wang, Lijie Zhang, Jinghui Zhao, Guixang Wang, Jerome Leslie Belinson
Health (Health) , 2016, DOI: 10.4236/health.2016.87071
Abstract: Background: Community based cervical cancer screening models using self-collection can effectively place the identification of who is positive in the hands of the patient. The key areas we have identified as critical are 1) education, 2) notification of screening opportunities, 3) registration, 4) submission of samples, 5) receiving results with an explanation, and 6) being advised where to receive evaluation and management from qualified healthcare personnel. Methods: Our primary objectives were to create, register, and pilot a website as a public platform for cervical cancer prevention for both city and rural, individual and organizational application. We selected two sites: Shenzhen City in China as the local city (individual participant) site, and Sangzhi County in Hunan Province as the remote (group management) site. The website was reviewable to all of China, but applications for screening and registration were open only to the women from the 2 pilot sites. In the local site, the women would first sign up (obtain a password) to view the website (www.mcareu.com), and then if they desired, they could register for screening using their true name and their state ID. After an offline confirmation of the address, the sampling kit would arrive. Results were available with additional education and guidance for care also on the website. Findings: 120,099 people nationwide visited the website in 27 months by the end of May, 2015, 1148 women from the sites registered at the website and 87.5% enrolled in the pilot trial. 72.3% of those testing positive returned for management. Virtually 100% of the registration/historical information was entered appropriately and 100% of the samples were handled properly. Interpretation: Web-based decision aids help patients through the uncertainties of healthcare. Applied to cervical cancer screening using self-collection, the effectiveness of the model specifically in respect to accessibility, education, registration, data input, and instructions for positive management was clearly demonstrated by this pilot as well as the potential for future diagnostics applicable to self-collection.
Attempted Transmission of Theileria annulata to Sheep and Goats with Hyalomma detritum and Hyalomma anatolicum
Hong Yin,Jianxun Luo,Qicai Zhang,Guiquan Guan,Bingyi Lu,Jianhong Guo,Yajun Wang,Wenshun Lu
Journal of Animal and Veterinary Advances , 2012,
Abstract: Three experiments were carried out to determine if Theileria annulata could be transmitted to small ruminants. Three Theileria-free batches of laboratory-reared larvae of Hyalomma detritum and larvae and nymphs of Hyalomma anatolicum anatolicum were applied to calves infected with Theileria annulata. The adult ticks of Hy. detritum and the nymphs and adult ticks of Hy. a. anatolicum which developed from these infestations were used for the experiments. In experiment 1, T. annulata sporozoites were inoculated into an intact calf. On day 20, the parasitaemia of the calf was 75% and it died from theileriosis. In experiment 2, one splenectomized sheep and one intact goat were each infested with 110 adult ticks of Hy. detritum. From 8-12 days post infestation, febrile responses were observed, but schizonts were not seen in lymph node biopsy smears. Subsequent examination of blood films for the presence of piroplasms of Theileria was also negative. In experiment 3, each of two sheep were infested with 500 nymphal ticks and each of two other sheep were infested with 200 adult ticks of Hy a. anatolicum. The results were the same as those of experiment 2. It was concluded that T. annulata only causes a mild febrile response and does not produce schizonts and piroplasms in sheep and goat when transmitted to these host species by Hy. detritum and Hy. a. anatolicum.
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