1,033 research outputs found
Perception of crisis of managers from China's state owned enterprises when making downsizing decisions
No full textPerception of crisis of managers from China's state-owned enterprises when making downsizing decisions
No full textBivariate Tensor-Product B-Splines in a Partly Linear Model
No full textAbstractIn some applications, the mean or median response is linearly related to some variables but the relation to additional variables are not easily parameterized. Partly linear models arise naturally in such circumstances. Suppose that a random sample {(Ti, Xi, Yi),i=1, 2, …, n} is modeled byYi=XTiβ0+g0(Ti)+errori, whereYiis a real-valued response,Xi∈RpandTiranges over a unit square, andg0is an unknown function with a certain degree of smoothness. We make use of bivariate tensor-product B-splines as an approximation of the functiong0and consider M-type regression splines by minimization of ∑ni=1ρ(Yi−XTiβ−gn(Ti)) for some convex functionρ. Mean, median and quantile regressions are included in this class. We show under appropriate conditions that the parameter estimate ofβachieves its information bound asymptotically and the function estimate ofg0attains the optimal rate of convergence in mean squared error. Our asymptotic results generalize directly to higher dimensions (for the variableT) provided that the functiong0is sufficiently smooth. Such smoothness conditions have often been assumed in the literature, but they impose practical limitations for the application of multivariate tensor product splines in function estimation. We also discuss the implementation of B-spline approximations based on commonly used knot selection criteria together with a simulation study of both mean and median regressions of partly linear models
CANONICAL ABERRATION THEORY IN ELECTROMAGNETIC MULTIPOLES
No full textIn a 2N-pole electromagnetic system, defining the electron optical Hamiltonian function, we have derived both general algebraic expressions (arbitrary N) and special numerical formulas (N = 3,4,5,6,7) for different aberrations from lower to higher order (i.e., the order of N - 1, N + 1, 2N - 3, 2N - 1, 3N - 5). The so-called canonical aberration theory in electromagnetic multipoles has thus been developed, which allows us to deduce angular dependencies of different aberrations and to examine the possibility for spherical correction of a round lens by using multipoles.Physics, AppliedSCI(E)0ARTICLE125968-59756
Development and application of a three-dimensional water quality model in a partially-mixed estuary, Southampton Water, UK
No full textThe aim of this research was to develop a 'transportable' water quality model for the Solent and Southampton Water estuarine system, as a part of an effort to examine the effects of human activity and natural processes on estuarine water quality. Dissolved oxygen (DO), as a main indicator of water quality, is influenced by physical, chemical and biological processes, and has been chosen as the core parameter to link the different processes to be modelled. Monthly surveys of DO, planktonic community respiration rates and other water quality parameters (temperature, salinity, chlorophyll, suspended particulate matter, inorganic nutrients etc.) in the Itchen Estuary and Southampton Water were conducted from January 1998 to April 1999. DO data shows that Southampton Water is a relatively healthy estuary, despite receiving considerable loads of oxygen demanding organic sewage effluent discharged from a number of points. A persistent moderate DO sag (DO saturation > 80%) was observed in the upper Itchen Estuary throughout the year. In the lower Itchen Estuary and Southampton Water, the waters were DO saturated during the non-phytoplankton growth season. Surface DO supersaturation was observed during the phytoplankton growth season especially during algal blooms, but no severe DO depletion was detected following the bloom collapse. Community respiration rates maintained a substantial level in the upper Itchen estuary, while in the lower estuary respiration rates were low during the non-phytoplankton season and increased during the phytoplankton growth season. It is suggested that the high winter respiration rate in the upper Itchen Estuary are sustained by inputs from external sources (rivers, sewage and industrial effluents) and that the summer increase in the lower estuary is a consequence of phytoplankton photosynthesis. Nutrients in the Itchen Estuary and Southampton Water show mainly conservative behaviour in a plot of nutrient concentration against salinity. The removal of the nutrients by phytoplankton activity occurred at high salinities during the spring to summer period.A 3-D finite element baroclinic hydrodynamic model with two-equation q2-q2l turbulence closure has been developed including a mass conservation scheme. The model successfully simulated the tides, tidal currents, and estuarine circulation in the Southampton Water and Solent estuarine system. The modelled tidal induced residual currents and water mass transportation in Southampton Water and the Solent have been examined. Model results show the existence of a predominant westward tidal induced residual current in the Solent. The tidal induced residual water mass transport is extremely limited in Southampton Water, except near the entrance to Southampton Water, where it joins the Solent. The estuarine circulation with surface, seaward flowing fresher water and bottom, landward flowing saltier water provides the main mechanism for water mass transport in the model. The short residence time of waters in the estuary estimated from the survey salinity data confirmed how effective the estuarine circulation is for sea water from the Solent to replace the water within Southampton Water. The trapping effect of estuarine circulation is also crucial for the water quality in the estuary. A water quality model has been developed and coupled with the 3-D hydrodynamic model. The water quality model consists of an external (dissolved oxygen-biochemical oxygen demand) model, which models the direct impact of external inputs (riverine discharge, domestic and industrial effluents) to the water quality, and an internal model, which simulates the impact of local estuarine phytoplankton growth on the water quality. DO and dissolved inorganic nutrients are the 'link substances' between the external model and internal model. The integrated water quality model output has been compared against the survey data for 1998, and has been shown to reproduce the spatial and temporal change in oxygen, nutrients, chlorophyll and planktonic respiration in Southampton Water
碱性介质中茜素黄R与牛血清白蛋白作用的荧光法研究
No full textThe interaction of alizarin yellow R(AYR) and bovine serum albumin (BSA) was investigated by fluorescence method in alkali buffer solution. It was shown that AYR had a powerful ability to quench the BSA fluorescence at excitation and emission wavelengths of lambda(exp) = 393 nm and lambda(exp) = 641 nm in the medium solution of pH 11. 00, and there were five binding sites of AYR to BSA; The combination reaction of AYR with BSA was a static quenching process, and from the effects of temperature on the fluorescence quenching rate of AYR-BSA and the Stern-Volmer quenching constant (K-SV) and the Lineweaver-Burk quenching constant (K-LB), the binding constant was calculated to be K = 1.6 X 10(4) L(.)mol-1; as the enthalpy change Delta H-theta < 0 and entropy change Delta S-theta < 0, and AYR has an ability to quench the BSA-CBBG fluorescence, it can be deduced that the Van der Walls force and hydrogen bond are the main binding forces between AYR and BSA
Safety and efficacy of acarbose in the treatment of diabetes in Chinese patients
No full textKe He*, Jun-Cheng Shi*, Xiao-Ming Mao Department of Endocrinology, Nanjing First Hospital Affiliated to Nanjing Medical University, Nanjing, People's Republic of China *These authors contributed equally to this work Abstract: Acarbose is an α-glucosidase inhibitor that is commonly used to control postprandial blood glucose. It functions as a competitive and reversible inhibitor of small intestinal brush border glucosidase, blocks the degradation of starch and sucrose, and delays the absorption of glucose and fructose in the alimentary tract. The starch content of a diet might alter the hypoglycemic effects of acarbose because of its mechanism of action. Chinese individuals consume a typical Eastern diet, which is characterized by a high intake of whole grains, legumes, vegetables, fruits, and fish. These dietary habits allow acarbose to be used extensively in the People's Republic of China. Several Chinese-based studies have demonstrated that the use of acarbose as a monotherapy had similar effects on other anti-diabetes agents in decreasing glycosylated hemoglobin (HbA1c) and blood glucose levels, and acarbose in combination with other anti-diabetic drugs could further reduce blood glucose and decrease the mean amplitude of glycemic excursions. Importantly, acarbose is safe and well tolerated, with a low incidence of adverse effects. This article provides a comprehensive review of the safety and efficacy of acarbose for the treatment of diabetes in Chinese patients. Keywords: acarbose, α-glucosidase inhibitor, efficacy, safet
Study on the reaction of proteinase from bacillus subtilis with Alizarin Complex
No full textThe interaction of bacillus subtilis proteinase(BSP) and Alizarin Complex(ALC) was investigated by spectrophotometric method in acidic solution(pH 4.20). When BSP was added into ALC, a red color was observed, which indicated the formation of BSP-ALC associated compound. The maximum absorption of the red color coordination compound was obtained at 510 mn. It was found that the red shift of maximum absorption of the complex was 85 rim. According to balance percolation method, molar ratio method and double wavelengh method, the apparent molar absorptivity epsilon(B) = 6.68 X 10(3) L center dot mol(-1) center dot cm(-1). Conditional constants were defined, the. maximum binding number n = 10, and the apparent binding constant K = 7.25 x 10(6) L center dot mol(-1). It was found that Scatchard model is appropriate in the treatment of data obtained here
Improved K-means algorithm for manufacturing process anomaly detection and recognition
No full textAnomaly detection and recognition are of prime importance in process industries. Faults are usually rare, and, therefore, predicting them is difficult . In this paper, a new greedy initialization method for the K-means algorithm is proposed to improve traditional K-means clustering techniques. The new initialization method tries to choose suitable initial points, which are well separated and have the potential to form high-quality clusters. Based on the clustering result of historical disqualification product data in manufacturing process which generated by the Improved-K-means algorithm, a prediction model which is used to detect and recognize the abnormal trend of the quality problems is constructed. This simple and robust alarm-system architecture for predicting incoming faults realizes the transition of quality problems from diagnosis afterward to prevention beforehand indeed. In the end, the alarm model was applied for prediction and avoidance of gear-wheel assembly faults at a gear-plant
Tunable visual color filter using microfluidic grating
No full textAuthor name used in this publication: X. M. Zhang2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishedVoR allowe
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