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Occurrence of circadian rhythms in hairy root cultures grown under controlled conditions

BIOTECHNOLOGY AND BIOENGINEERING 2004年第6期88卷 722-729页

作者： Lanoue, A Shakourzadeh, K Marison, I Laberche, JC Christen, P Sangwan-Norreel, B Boitel-Conti, M Univ Picardie Lab Androgenese & Biotechnol F-80039 Amiens 01 France Univ Technol Compiegne Dept Genie Chim F-60206 Compiegne France Swiss Fed Inst Technol EPFL Lab Chem & Biol Engn Lausanne Switzerland Univ Geneva Lab Chim Analyt Pharmaceut Geneva Switzerland

Hairy roots obtained by transformation via Agrobacterium rhizogenes provide an artificial plant material devoid of aerial parts with high growth on hormone-free media. Fundamental knowledge of hairy root physiology is essential to develop and control its culture. In contrast to shake-flask cultures, a bioreactor set-up combined with on-line data logging provides an efficient tool to study rapid physiological variations in hairy root cultures. Datura innoxia hairy roots were grown in a bioreactor equipped with on-line data analyses of pH, dissolved oxygen (pO(2)), conductivity, oxygen, and carbon dioxide. The experiments were done at a constant temperature and in the absence of light cues. The results obtained showed that the carbon dioxide evolution rate (CER) presented regular oscillations during the culture. Similar oscillations were also observed for the oxygen uptake rate (OUR). These signals were treated mathematically to look for the existence of a rhythm. An autocorrelation function was used to detect any periodic components. The results demonstrate that hairy root respiration exhibited peaks of 1 day. These oscillations, having a period of about 24 h, were also observed in pH and conductivity signals, although not for the pO(2) signal. The data acquired in the absence of hairy roots showed that the observed periodic behavior was not an artifact. No effect on rhythms was observed by the imposition of an external "day/night" cycle. The fact that oscillations persisted in the absence of external stimuli, with a free-running period of 24 h, suggests that a circadian rhythm exists in hairy roots of D. innoxia. (C) 2004 Wiley Periodicals, Inc.

关键词： hairy roots bioreactor circadian rhythm auto-correlation function

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A Simple Approach for Specifying Velocity Inflow Boundary Conditions in Simulations of Turbulent Opposed-Jet Flows

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FLOW TURBULENCE AND COMBUSTION 2017年第1期98卷 131-153页

作者： Tirunagari, Ranjith R. Pettit, Michael W. A. Kempf, Andreas M. Pope, Stephen B. Cornell Univ Sibley Sch Mech & Aerosp Engn Ithaca NY 14853 USA Imperial Coll London Dept Mech Engn South Kensington CampusExhibit Rd London SW7 2AZ England Univ Duisburg Essen Inst Combust & Gas Dynam IVG D-47048 Duisburg Germany Univ Duisburg Essen Ctr Computat Sci & Simulat D-47048 Duisburg Germany CD Adapco 21800 Haggerty RdSuite 300 Northville MI 48167 USA

A new methodology is developed to specify inflow boundary conditions for the velocity field at the nozzle exit planes in turbulent counterflow simulations. The turbulent counterflow configuration consists of two coaxial opposed nozzles which emit highly-turbulent streams of varying species compositions depending on the mode considered. The specification of velocity inflow boundary conditions at the nozzle exits in the counterflow configuration is non-trivial because of the unique turbulence field generated by the turbulence generating plates (TGPs) upstream of the nozzle exits. In the method presented here, a single large-eddy simulation (LES) is performed in a large domain that spans the region between the TGPs of the nozzles, and the time series of the velocity fields at the nozzle exit planes are recorded. To provide inflow boundary conditions at the nozzle exit planes for simulations under other conditions (e.g., different stream compositions, bulk velocity, TGP location), transformations are performed on the recorded time series: the mean and r.m.s. (root-mean-square) quantities of velocity, as well as the longitudinal integral length scale on the centerline, at the nozzle exits in simulations are matched to those observed in experiments, thereby matching the turbulent Reynolds number R e (t) . The method is assessed by implementing it in coupled large-eddy simulation/probability density function (LES/PDF) simulations on a small cylindrical domain between the nozzle exit planes for three different modes of the counterflow configuration: N (2) vs. N (2);N (2) vs. hot combustion products;and C H (4)/N (2) vs. O (2). The inflow method is found to be successful as the first and second moments of velocity from the LES/PDF simulations agree well with the experimental data on the centerline for all three modes. This simple yet effective inflow strategy can be applied to eliminate the computational cost required to simulate the flow field upstream of the nozzle exits.

关键词： Turbulent counterflow simulations Velocity inflow boundary conditions LES/PDF auto-correlation function Velocity statistics

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Reliability analysis of stability against piping and sliding in diversion dams, considering four cutoff wall configurations

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COMPUTERS AND GEOTECHNICS 2018年第Jun.期98卷 217-231页

作者： Hekmatzadeh, Ali Akbar Zarei, Farshad Johari, Ali Haghighi, Ali Torabi Shiraz Univ Technol Dept Civil & Environm Engn POB 71555-313 Shiraz Iran Univ Oulu Water Resources & Environm Engn Res Grp POB 4300 FIN-90014 Oulu Finland

The stability against piping and sliding, which is subject to numerous sources of uncertainty, is of great importance in the design of diversion dams. In this study, the performance of four cutoff wall configurations, including a single wall and two walls with half the length of the single wall, was evaluated stochastically using the random finite element method. The Cholesky decomposition technique in conjunction with three types of auto-correlation function (ACF) was employed to generate numerous random fields. The results indicate that the probabilities of failure related to different cutoff wall configurations are similar, considering isotropic hydraulic conductivity. However, there are noticeable differences between the probabilities of failure of these configurations in anisotropic situations. Moreover, the use of a single cutoff wall on the upstream face of an impervious blanket provides the lowest probability of failure for piping. In addition, the exponential ACF ends up with greater exit hydraulic gradients than the second-order Markov and binary noise ACFs. In addition, the sliding stability of the ordinary and earthquake load combinations was examined stochastically using random field theory and Monte Carlo Simulation (MCS). The probability of failure appears to increase with an increase in the autocorrelation distance.

关键词： Probability of failure Diversion dam Piping Sliding stability Random finite element method auto-correlation function

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An Universal MMSE Channel Estimator for OFDM Receiver

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WIRELESS PERSONAL COMMUNICATIONS 2017年第3期94卷 659-673页

作者： Wei, Hua Huang, Yao Zhang, Tianqi Li, Li Chengdu Univ Informat Technol Sichuan Higher Educ Inst Meteorol Informat & Signal Proc Key Lab Chengdu Peoples R China Chongqing Univ Posts & Telecommun CQUPT Sch Commun & Informat Engn Chongqing Peoples R China

In this paper, we re-derived the new auto-correlation function based on Jake's Model, and an universal minimum mean square error (MMSE) channel estimator are proposed based on the new auto-correlation function. Therefore, the proposed MMSE channel estimator can be adopted to various channel scenarios owing its inherent robustness. The performance of the MMSE channel estimator is investigated through a practise DVB-T standard, which shown that the MMSE channel estimator can achieve the extraordinary minimum square error performance at a low complexity.

关键词： OFDM MMSE auto-correlation function DDCE DVB-T

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Effects of noise correlation on the coherence of a forced van der Pol type birhythmic system

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COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION 2018年 62卷 1-17页

作者： Yamapi, R. Yonkeu, R. Mbakob Filatrella, G. Tchawoua, C. Univ Douala Fac Sci Dept Phys Fundamental Phys Lab Box 24 157 Douala Cameroon Max Planck Inst Math Sci Inselstr 22 D-04103 Leipzig Germany Univ Yaounde I Fac Sci Dept Phys Lab Mech & Mat Box 812 Yaounde Cameroon Univ Sannio CNSIM Dept Sci & Technol Via Port Arsa 11 I-82100 Benevento Italy Univ Sannio CNSIM Salerno Unit Via Port Arsa 11 I-82100 Benevento Italy

We investigate the effects of noise correlation on the coherence of a forced van der Pol type birhythmic system. The coherence of the dynamics on the time scale of intrawell oscillations, as measured by the signal-to-noise-ratio, is shown to be maximized for an appropriate choice of the noise intensity and of the noise correlation time. Other measures, related to the autocorrelation function and applicable on the longer time scale of interwell oscillations do not exhibit such nonlinear behavior. When occurs, the coherence appears similar to noise induced stochastic resonance in ordinary bistable potential systems, while the investigated birhythmic system only posses a nonequilibrium or quasi-potential associated to the orbits. Thus, it is demonstrated that correlated noise, even if the attractors are not fix points but orbits, can give rise to stochastic resonance. (c) 2018 Elsevier B.V. All rights reserved.

关键词： correlation time Birhythmic system auto-correlation function Signal-to-noise ratio Stochastic resonance

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Stochastic finite element analysis of plate structures by weighted integral method

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STRUCTURAL ENGINEERING AND MECHANICS 1996年第6期4卷 703-715页

作者： Choi, CK Noh, HC Department of Civil Engineering Korea Advanced Institute of Science & Technology

In stochastic analysis, the randomness of the structural parameters is taken into consideration and the response variability is obtained in addition to the conventional (mean) response. In the present paper the structural response variability of plate structure is calculated using the weighted integral method and is compared with the results obtained by different methods. The stochastic field is assumed to be normally distributed and to have the homogeneity. The decomposition of strain-displacement matrix enabled us to extend the formulation to the stochastic analysis with the quadratic elements in the weighted integral method A new auto-correlation function is derived considering the uncertainty of plate thickness. The results obtained in the numerical examples by two different methods, i.e., weighted integral method and Monte Carlo simulation, are in a close agreement. In the case of the variable plate thickness, the obtained results are in good agreement with those of Lawrence and Monte Carlo simulation.

关键词： stochastic finite element analysis weighted integral method auto-correlation function material and geometrical randomness Monte Carlo simulation

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A reverberation-time-aware DNN approach leveraging spatial information for microphone array dereverberation

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EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2017年第1期2017卷 1页

作者： Wu, Bo Yang, Minglei Li, Kehuang Huang, Zhen Siniscalchi, Sabato Marco Wang, Tong Lee, Chin-Hui Xidian Univ Natl Lab Radar Signal Proc Xian Shaanxi Peoples R China Georgia Inst Technol Sch Elect & Comp Engn Atlanta GA 30332 USA Univ Enna Kore Dept Telecommun Enna Italy

A reverberation-time-aware deep-neural-network (DNN)-based multi-channel speech dereverberation framework is proposed to handle a wide range of reverberation times (RT60s). There are three key steps in designing a robust system. First, to accomplish simultaneous speech dereverberation and beamforming, we propose a framework, namely DNNSpatial, by selectively concatenating log-power spectral (LPS) input features of reverberant speech from multiple microphones in an array and map them into the expected output LPS features of anechoic reference speech based on a single deep neural network (DNN). Next, the temporal auto-correlation function of received signals at different RT60s is investigated to show that RT60-dependent temporal-spatial contexts in feature selection are needed in the DNNSpatial training stage in order to optimize the system performance in diverse reverberant environments. Finally, the RT60 is estimated to select the proper temporal and spatial contexts before feeding the log-power spectrum features to the trained DNNs for speech dereverberation. The experimental evidence gathered in this study indicates that the proposed framework outperforms the state-of-the-art signal processing dereverberation algorithm weighted prediction error (WPE) and conventional DNNSpatial systems without taking the reverberation time into account, even for extremely weak and severe reverberant conditions. The proposed technique generalizes well to unseen room size, array geometry and loudspeaker position, and is robust to reverberation time estimation error.

关键词： Deep neural networks (DNNs) Simultaneous speech dereverberation and beamforming auto-correlation function Temporal and spatial contexts Reverberation-time-aware (RTA)

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DETERMINATION OF DYNAMIC CHARACTERISTICS OF OFFSHORE PLATFORMS FROM RANDOM-VARIABLES

SOCIETY OF PETROLEUM ENGINEERS JOURNAL

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SOCIETY OF PETROLEUM ENGINEERS JOURNAL 1975年第6期15卷 502-508页

作者： EARLE, EN SHELL DEV CO BELLAIRE RES CTRHOUSTONTX 77000

Earle, E.N., Member SPE-AIME, Shell Development Co., Houston, ***. The dynamic response characteristics of three offshore production platforms have been determined. The technique used involves curve fitting to match a theoretical spectral-density function to the spectral-density function computed from measured random vibration. Results in the form of natural frequencies and damping are presented for the three structures. These results show that the damping in offshore platforms is about 3.5 percent of ***. Structures of all sizes and shapes are usually subjected to time-varying loads. These loads can be created by wind, waves, earthquakes, or machinery. The effect on the structure, its dynamic response, is of utmost importance to the design engineer since the dynamic response of a structure can exceed the static response by a significant factor. If a structure were to be loaded such that the frequency of the load was about equal to the natural frequency of the structure, the stresses in the members caused by the dynamic load would far exceed the stresses caused by the static load applied to the structure. The size of the dynamic stresses within the structure depends not only on the size of the external load, but also on the amount of damping of the structure. Theoretical methods are available for computing the natural frequencies and the dynamic response of various types of structures. These methods usually require that an estimate of the amount of damping be made to complete computations. For the typical deep-water offshore drilling platform, which is anchored to the ocean floor by piling, it would be desirable to know the actual damping in the structure and the structure's natural frequencies to compare with theoretical predictions or estimates. The approach used here to determine the actual damping and natural frequencies of an offshore platform involved acquiring random vibrations data platform involved acquiring random vibrations data

关键词： Reservoir Characterization machine learning Upstream Oil & Gas Fourier Transform frequency natural frequency Artificial Intelligence auto-correlation function subsea system recorder Information Management and Systems Offshore Facilities and Subsea Systems Reservoir Characterization Seismic processing and interpretation

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Single photon emission from in situ created nitrogen-vacancies in chemical vapor deposition grown single crystal diamond

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PHYSICA SCRIPTA 2024年第4期99卷 045106-045106页

作者： Shukla, Vivek K. Poswal, H. K. Kala, A. Achanta, V. G. Majumder, A. Saha, K. Rai, Padmnabh Univ Mumbai UM DAE Ctr Excellence Basic Sci Sch Phys Sci Mumbai 400098 India Bhabha Atom Res Ctr High Pressure Phys Div Mumbai 400085 India Tata Inst Fundamental Res Mumbai 400005 India Indian Inst Technol Dept Elect Engn Mumbai 400076 India

The work reports the manipulation of nitrogen-vacancy centres in chemical vapor deposition grown single crystal diamonds by incorporation of nitrogen, boron and oxygen during the growth process. Single photon emission measurements were performed on diamond samples by using continuous wave and pulsed laser of wavelength 532 nm. The second order auto-correlation measurement (0.3 correlation measurement (0.6

关键词： Single crystal diamond single photon emission nitrogen-vacancies auto-correlation function

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A Novel Adaptive Unambiguous Acquisition Scheme for CBOC Signal Based on Galileo

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IEICE TRANSACTIONS ON COMMUNICATIONS 2014年第6期E97B卷 1157-1165页

作者： Liang, Ce Sun, Xiyan Ji, Yuanfa Liu, Qinghua Liao, Guisheng Guilin Univ Elect Technol Coll Informat & Commun Guilin Peoples R China Guilin Univ Elect Technol Guilin Peoples R China Xidian Univ Coll Elect Engn Xian Peoples R China

The composite binary offset carrier (CBOC) modulated signal contains multi-peaks in its auto-correlation function, which brings ambiguity to the signal acquisition process of a GNSS receiver. Currently, most traditional ambiguity-removing schemes for CBOC signal acquisition approximate CBOC signal as a HOC signal, which may incur performance degradation. Based on Galileo El CBOC signal, this paper proposes a novel adaptive ambiguity-removing acquisition scheme which doesn't adopt the approximation used in traditional schemes. According to the energy ratio of each sub-code of CBOC signal, the proposed scheme can self-adjust its local reference code to achieve unambiguous and precise signal synchronization. Monte Carlo simulation is conducted in this paper to analyze the performance of the proposed scheme and three traditional schemes. Simulation results show that the proposed scheme has higher detection probability and less mean acquisition time than the other three schemes, which verify the superiority of the proposed scheme.

关键词： CBOC Galileo auto-correlation function ambiguity-removing acquisition Monte Carlo simulation

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