WorldWideScience

Sample records for levels varied depending

  1. Modeling the time-varying and level-dependent effects of the medial olivocochlear reflex in auditory nerve responses.

    Science.gov (United States)

    Smalt, Christopher J; Heinz, Michael G; Strickland, Elizabeth A

    2014-04-01

    The medial olivocochlear reflex (MOCR) has been hypothesized to provide benefit for listening in noisy environments. This advantage can be attributed to a feedback mechanism that suppresses auditory nerve (AN) firing in continuous background noise, resulting in increased sensitivity to a tone or speech. MOC neurons synapse on outer hair cells (OHCs), and their activity effectively reduces cochlear gain. The computational model developed in this study implements the time-varying, characteristic frequency (CF) and level-dependent effects of the MOCR within the framework of a well-established model for normal and hearing-impaired AN responses. A second-order linear system was used to model the time-course of the MOCR using physiological data in humans. The stimulus-level-dependent parameters of the efferent pathway were estimated by fitting AN sensitivity derived from responses in decerebrate cats using a tone-in-noise paradigm. The resulting model uses a binaural, time-varying, CF-dependent, level-dependent OHC gain reduction for both ipsilateral and contralateral stimuli that improves detection of a tone in noise, similarly to recorded AN responses. The MOCR may be important for speech recognition in continuous background noise as well as for protection from acoustic trauma. Further study of this model and its efferent feedback loop may improve our understanding of the effects of sensorineural hearing loss in noisy situations, a condition in which hearing aids currently struggle to restore normal speech perception.

  2. Time varying behavior of the loudspeaker suspension: Displacement level dependency

    DEFF Research Database (Denmark)

    Agerkvist, Finn T.; Pedersen, Bo Rohde

    2009-01-01

    The compliance of the loudspeaker suspension is known to depend on the recent excitation level history. Previous investigations have shown that the electrical power as well as displacement and velocity plays a role. In this paper the hypothesis that the changes in compliance are caused mainly...... by how much the suspension has been stretched, i.e. the maximum displacement, is investigated. For this purpose the changes in compliance are measured when exposing the speaker to different levels and types of electrical excitation signals, as well as mechanical excitation only. For sinusoidal excitation...... the change in compliance is shown to depend primarily on maximum displacement. But for square pulse excitation the duration of the excitation also plays an important role...

  3. Inferring time‐varying recharge from inverse analysis of long‐term water levels

    Science.gov (United States)

    Dickinson, Jesse; Hanson, R.T.; Ferré, T.P.A.; Leake, S.A.

    2004-01-01

    Water levels in aquifers typically vary in response to time‐varying rates of recharge, suggesting the possibility of inferring time‐varying recharge rates on the basis of long‐term water level records. Presumably, in the southwestern United States (Arizona, Nevada, New Mexico, southern California, and southern Utah), rates of mountain front recharge to alluvial aquifers depend on variations in precipitation rates due to known climate cycles such as the El Niño‐Southern Oscillation index and the Pacific Decadal Oscillation. This investigation examined the inverse application of a one‐dimensional analytical model for periodic flow described by Lloyd R. Townley in 1995 to estimate periodic recharge variations on the basis of variations in long‐term water level records using southwest aquifers as the case study. Time‐varying water level records at various locations along the flow line were obtained by simulation of forward models of synthetic basins with applied sinusoidal recharge of either a single period or composite of multiple periods of length similar to known climate cycles. Periodic water level components, reconstructed using singular spectrum analysis (SSA), were used to calibrate the analytical model to estimate each recharge component. The results demonstrated that periodic recharge estimates were most accurate in basins with nearly uniform transmissivity and the accuracy of the recharge estimates depends on monitoring well location. A case study of the San Pedro Basin, Arizona, is presented as an example of calibrating the analytical model to real data.

  4. Varying ultrasound power level to distinguish surgical instruments and tissue.

    Science.gov (United States)

    Ren, Hongliang; Anuraj, Banani; Dupont, Pierre E

    2018-03-01

    We investigate a new framework of surgical instrument detection based on power-varying ultrasound images with simple and efficient pixel-wise intensity processing. Without using complicated feature extraction methods, we identified the instrument with an estimated optimal power level and by comparing pixel values of varying transducer power level images. The proposed framework exploits the physics of ultrasound imaging system by varying the transducer power level to effectively distinguish metallic surgical instruments from tissue. This power-varying image-guidance is motivated from our observations that ultrasound imaging at different power levels exhibit different contrast enhancement capabilities between tissue and instruments in ultrasound-guided robotic beating-heart surgery. Using lower transducer power levels (ranging from 40 to 75% of the rated lowest ultrasound power levels of the two tested ultrasound scanners) can effectively suppress the strong imaging artifacts from metallic instruments and thus, can be utilized together with the images from normal transducer power levels to enhance the separability between instrument and tissue, improving intraoperative instrument tracking accuracy from the acquired noisy ultrasound volumetric images. We performed experiments in phantoms and ex vivo hearts in water tank environments. The proposed multi-level power-varying ultrasound imaging approach can identify robotic instruments of high acoustic impedance from low-signal-to-noise-ratio ultrasound images by power adjustments.

  5. Response of rabbits to varying levels of cassava and Leucaena ...

    African Journals Online (AJOL)

    Response of rabbits to varying levels of cassava and Leucaena leucocephala leaf meal diets. ... Bulletin of Animal Health and Production in Africa ... An experiment was carried out to determine the performance, haematology, carcass characteristics and sensory evaluation of meat from rabbits (n = 30) fed varying levels of ...

  6. Delay-Dependent Guaranteed Cost Control of an Interval System with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Xiao Min

    2009-01-01

    Full Text Available This paper concerns the problem of the delay-dependent robust stability and guaranteed cost control for an interval system with time-varying delay. The interval system with matrix factorization is provided and leads to less conservative conclusions than solving a square root. The time-varying delay is assumed to belong to an interval and the derivative of the interval time-varying delay is not a restriction, which allows a fast time-varying delay; also its applicability is broad. Based on the Lyapunov-Ktasovskii approach, a delay-dependent criterion for the existence of a state feedback controller, which guarantees the closed-loop system stability, the upper bound of cost function, and disturbance attenuation lever for all admissible uncertainties as well as out perturbation, is proposed in terms of linear matrix inequalities (LMIs. The criterion is derived by free weighting matrices that can reduce the conservatism. The effectiveness has been verified in a number example and the compute results are presented to validate the proposed design method.

  7. Improving Delay-Range-Dependent Stability Condition for Systems with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Wei Qian

    2013-01-01

    Full Text Available This paper discusses the delay-range-dependent stability for systems with interval time-varying delay. Through defining the new Lyapunov-Krasovskii functional and estimating the derivative of the LKF by introducing new vectors, using free matrices and reciprocally convex approach, the new delay-range-dependent stability conditions are obtained. Two well-known examples are given to illustrate the less conservatism of the proposed theoretical results.

  8. Delay-Dependent Guaranteed Cost H∞ Control of an Interval System with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Zhongke Shi

    2009-01-01

    Full Text Available This paper concerns the problem of the delay-dependent robust stability and guaranteed cost H∞ control for an interval system with time-varying delay. The interval system with matrix factorization is provided and leads to less conservative conclusions than solving a square root. The time-varying delay is assumed to belong to an interval and the derivative of the interval time-varying delay is not a restriction, which allows a fast time-varying delay; also its applicability is broad. Based on the Lyapunov-Ktasovskii approach, a delay-dependent criterion for the existence of a state feedback controller, which guarantees the closed-loop system stability, the upper bound of cost function, and disturbance attenuation lever for all admissible uncertainties as well as out perturbation, is proposed in terms of linear matrix inequalities (LMIs. The criterion is derived by free weighting matrices that can reduce the conservatism. The effectiveness has been verified in a number example and the compute results are presented to validate the proposed design method.

  9. Response of maize ( Zea mays L.) to varied moisture levels under ...

    African Journals Online (AJOL)

    Laboratory and glasshouse trials were used to determine the response of maize plants to varied moisture levels under Striga lutea infestation. Six moisture levels (1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 ml) were applied to striga seed for germination count in the laboratory, while five moisture levels (300, 600, 900, 1200 and 1500 ml) ...

  10. Delay-Dependent Exponential Stability for Discrete-Time BAM Neural Networks with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Yonggang Chen

    2008-01-01

    Full Text Available This paper considers the delay-dependent exponential stability for discrete-time BAM neural networks with time-varying delays. By constructing the new Lyapunov functional, the improved delay-dependent exponential stability criterion is derived in terms of linear matrix inequality (LMI. Moreover, in order to reduce the conservativeness, some slack matrices are introduced in this paper. Two numerical examples are presented to show the effectiveness and less conservativeness of the proposed method.

  11. The performance of broiler finisher birds fed varying levels of feather ...

    African Journals Online (AJOL)

    The performance of broiler finisher birds fed varying levels of feather meal as replacement for soya bean meal. ... meal increased, feed cost/ kg weight gain increased and both differed significantly (P<0.05) between treatment means, while the birds tolerated feather meal up to 7.5% inclusion level, 2.5% was the optimal.

  12. Effects of Varying Gravity Levels on fNIRS Headgear Performance and Signal Recovery

    Science.gov (United States)

    Mackey, Jeffrey R.; Harrivel, Angela R.; Adamovsky, Grigory; Lewandowski, Beth E.; Gotti, Daniel J.; Tin, Padetha; Floyd, Bertram M.

    2013-01-01

    This paper reviews the effects of varying gravitational levels on functional Near-Infrared Spectroscopy (fNIRS) headgear. The fNIRS systems quantify neural activations in the cortex by measuring hemoglobin concentration changes via optical intensity. Such activation measurement allows for the detection of cognitive state, which can be important for emotional stability, human performance and vigilance optimization, and the detection of hazardous operator state. The technique depends on coupling between the fNIRS probe and users skin. Such coupling may be highly susceptible to motion if probe-containing headgear designs are not adequately tested. The lack of reliable and self-applicable headgear robust to the influence of motion artifact currently inhibits its operational use in aerospace environments. Both NASAs Aviation Safety and Human Research Programs are interested in this technology as a method of monitoring cognitive state of pilots and crew.

  13. Time-varying market integration and expected returns in emerging mrkets

    NARCIS (Netherlands)

    de Jong, F.C.J.M.; de Roon, F.

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematicrisk as measured by their beta relative to the world portfolio as well as on the level ofintegration in that market. The level of integration is a time-varying variable that depends on themarket value

  14. Time Varying Market Integration and Expected Rteurns in Emerging Markets

    NARCIS (Netherlands)

    de Jong, F.C.J.M.; de Roon, F.A.

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematic risk as measured by their beta relative to the world portfolio as well as on the level of integration in that market.The level of integration is a time-varying variable that depends on the market value

  15. Ventilation distribution measured with EIT at varying levels of pressure support and Neurally Adjusted Ventilatory Assist in patients with ALI.

    Science.gov (United States)

    Blankman, Paul; Hasan, Djo; van Mourik, Martijn S; Gommers, Diederik

    2013-06-01

    The purpose of this study was to compare the effect of varying levels of assist during pressure support (PSV) and Neurally Adjusted Ventilatory Assist (NAVA) on the aeration of the dependent and non-dependent lung regions by means of Electrical Impedance Tomography (EIT). We studied ten mechanically ventilated patients with Acute Lung Injury (ALI). Positive-End Expiratory Pressure (PEEP) and PSV levels were both 10 cm H₂O during the initial PSV step. Thereafter, we changed the inspiratory pressure to 15 and 5 cm H₂O during PSV. The electrical activity of the diaphragm (EAdi) during pressure support ten was used to define the initial NAVA gain (100 %). Thereafter, we changed NAVA gain to 150 and 50 %, respectively. After each step the assist level was switched back to PSV 10 cm H₂O or NAVA 100 % to get a new baseline. The EIT registration was performed continuously. Tidal impedance variation significantly decreased during descending PSV levels within patients, whereas not during NAVA. The dorsal-to-ventral impedance distribution, expressed according to the center of gravity index, was lower during PSV compared to NAVA. Ventilation contribution of the dependent lung region was equally in balance with the non-dependent lung region during PSV 5 cm H₂O, NAVA 50 and 100 %. Neurally Adjusted Ventilatory Assist ventilation had a beneficial effect on the ventilation of the dependent lung region and showed less over-assistance compared to PSV in patients with ALI.

  16. Study on the Variation of Groundwater Level under Time-varying Recharge

    Science.gov (United States)

    Wu, Ming-Chang; Hsieh, Ping-Cheng

    2017-04-01

    The slopes of the suburbs come to important areas by focusing on the work of soil and water conservation in recent years. The water table inside the aquifer is affected by rainfall, geology and topography, which will result in the change of groundwater discharge and water level. Currently, the way to obtain water table information is to set up the observation wells; however, owing to that the cost of equipment and the wells excavated is too expensive, we develop a mathematical model instead, which might help us to simulate the groundwater level variation. In this study, we will discuss the groundwater level change in a sloping unconfined aquifer with impermeable bottom under time-varying rainfall events. Referring to Child (1971), we employ the Boussinesq equation as the governing equation, and apply the General Integral Transforms Method (GITM) to analyzing the groundwater level after linearizing the Boussinesq equation. After comparing the solution with Verhoest & Troch (2000) and Bansal & Das (2010), we get satisfactory results. To sum up, we have presented an alternative approach to solve the linearized Boussinesq equation for the response of groundwater level in a sloping unconfined aquifer. The present analytical results combine the effect of bottom slope and the time-varying recharge pattern on the water table fluctuations. Owing to the limitation and difficulty of measuring the groundwater level directly, we develop such a mathematical model that we can predict or simulate the variation of groundwater level affected by any rainfall events in advance.

  17. Periodic solution for state-dependent impulsive shunting inhibitory CNNs with time-varying delays.

    Science.gov (United States)

    Şaylı, Mustafa; Yılmaz, Enes

    2015-08-01

    In this paper, we consider existence and global exponential stability of periodic solution for state-dependent impulsive shunting inhibitory cellular neural networks with time-varying delays. By means of B-equivalence method, we reduce these state-dependent impulsive neural networks system to an equivalent fix time impulsive neural networks system. Further, by using Mawhin's continuation theorem of coincide degree theory and employing a suitable Lyapunov function some new sufficient conditions for existence and global exponential stability of periodic solution are obtained. Previous results are improved and extended. Finally, we give an illustrative example with numerical simulations to demonstrate the effectiveness of our theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Comparison of creep behavior under varying load/temperature conditions between Hastelloy XR alloys with different boron content levels

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Nakajima, Hajime; Shindo, Masami; Tanabe, Tatsuhiko; Nakasone, Yuji.

    1996-01-01

    In the design of the high-temperature components, it is often required to predict the creep rupture life under the conditions in which the stress and/or temperature may vary by using the data obtained with the constant load and temperature creep rupture tests. Some conventional creep damage rules have been proposed to meet the above-mentioned requirement. Currently only limited data are available on the behavior of Hastelloy XR, which is a developed alloy as the structural material for high-temperature components of the High-Temperature Engineering Test Reactor (HTTR), under varying stress and/or temperature creep conditions. Hence a series of constant load and temperature creep rupture tests as well as varying load and temperature creep rupture tests was carried out on two kinds of Hastelloy XR alloys whose boron content levels are different, i.e., below 10 and 60 mass ppm. The life fraction rule completely fails in the prediction of the creep rupture life of Hastelloy XR with 60 mass ppm boron under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR with below 10 mass ppm boron. The change of boron content level of the material during the tests is the most probable source of impairing the applicability of the life fraction rule to Hastelloy XR whose boron content level is 60 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the two stage creep test conditions from 1000 to 900degC. The trend observed in the two stage creep tests from 900 to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (J.P.N.)

  19. Delay-Dependent Asymptotic Stability of Cohen-Grossberg Models with Multiple Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Xiaofeng Liao

    2007-01-01

    Full Text Available Dynamical behavior of a class of Cohen-Grossberg models with multiple time-varying delays is studied in detail. Sufficient delay-dependent criteria to ensure local and global asymptotic stabilities of the equilibrium of this network are derived by constructing suitable Lyapunov functionals. The obtained conditions are shown to be less conservative and restrictive than those reported in the known literature. Some numerical examples are included to demonstrate our results.

  20. Online Support Vector Regression with Varying Parameters for Time-Dependent Data

    International Nuclear Information System (INIS)

    Omitaomu, Olufemi A.; Jeong, Myong K.; Badiru, Adedeji B.

    2011-01-01

    Support vector regression (SVR) is a machine learning technique that continues to receive interest in several domains including manufacturing, engineering, and medicine. In order to extend its application to problems in which datasets arrive constantly and in which batch processing of the datasets is infeasible or expensive, an accurate online support vector regression (AOSVR) technique was proposed. The AOSVR technique efficiently updates a trained SVR function whenever a sample is added to or removed from the training set without retraining the entire training data. However, the AOSVR technique assumes that the new samples and the training samples are of the same characteristics; hence, the same value of SVR parameters is used for training and prediction. This assumption is not applicable to data samples that are inherently noisy and non-stationary such as sensor data. As a result, we propose Accurate On-line Support Vector Regression with Varying Parameters (AOSVR-VP) that uses varying SVR parameters rather than fixed SVR parameters, and hence accounts for the variability that may exist in the samples. To accomplish this objective, we also propose a generalized weight function to automatically update the weights of SVR parameters in on-line monitoring applications. The proposed function allows for lower and upper bounds for SVR parameters. We tested our proposed approach and compared results with the conventional AOSVR approach using two benchmark time series data and sensor data from nuclear power plant. The results show that using varying SVR parameters is more applicable to time dependent data.

  1. Response-only modal identification using random decrement algorithm with time-varying threshold level

    International Nuclear Information System (INIS)

    Lin, Chang Sheng; Tseng, Tse Chuan

    2014-01-01

    Modal Identification from response data only is studied for structural systems under nonstationary ambient vibration. The topic of this paper is the estimation of modal parameters from nonstationary ambient vibration data by applying the random decrement algorithm with time-varying threshold level. In the conventional random decrement algorithm, the threshold level for evaluating random dec signatures is defined as the standard deviation value of response data of the reference channel. The distortion of random dec signatures may be, however, induced by the error involved in noise from the original response data in practice. To improve the accuracy of identification, a modification of the sampling procedure in random decrement algorithm is proposed for modal-parameter identification from the nonstationary ambient response data. The time-varying threshold level is presented for the acquisition of available sample time history to perform averaging analysis, and defined as the temporal root-mean-square function of structural response, which can appropriately describe a wide variety of nonstationary behaviors in reality, such as the time-varying amplitude (variance) of a nonstationary process in a seismic record. Numerical simulations confirm the validity and robustness of the proposed modal-identification method from nonstationary ambient response data under noisy conditions.

  2. Association between tobacco industry denormalization beliefs, tobacco control community discontent and smokers' level of nicotine dependence.

    Science.gov (United States)

    Kushnir, Vladyslav; Selby, Peter; Cunningham, John A

    2013-07-01

    Tobacco industry denormalization (TID) informs the public about the tobacco industry's role in the tobacco epidemic and is an important component of a comprehensive tobacco control strategy. Although TID beliefs have been noted in adult smokers and associated with intent to quit, research has not evaluated whether they are affected by smokers' level of nicotine dependence. The present article sought to concurrently examine how attitudes towards the tobacco industry and tobacco control groups may differ among smokers of varying levels of nicotine dependence. In addition, it evaluated how these attitudes and beliefs may be associated with smokers' intentions to reduce or quit smoking. A random digit dialing telephone survey was conducted of 889 Canadian current daily smokers, 18 years and older. Attitudes towards the tobacco industry were mixed among the entire cohort and differences in beliefs towards the tobacco industry were not found among smokers of varying levels of nicotine dependence. However, smokers that held strong TID beliefs were 5 times more intent to quit smoking than those without such beliefs. Compared to smokers with low level of nicotine dependence, heavy smokers were more likely to report strong overall displeasure with the tobacco control community (OR=1.98, 95% CI=1.23-3.19, p=0.005), however there were no differences with regards to future intent to quit. The absence of strong negative sentiment toward the tobacco industry among smokers as a whole suggests that more targeted anti-industry messages are needed, raising greater awareness of tobacco industry practices within smokers and non-smokers alike. As heavier smokers' discontent with the tobacco control community highlights increasing social disapproval and pressure to quit smoking, future educational and media strategies used for smoking cessation purposes may benefit from emphasizing more of the positive attributes associated with quitting smoking, as opposed to the negative features of

  3. Novel Assay of Metformin Levels in Patients With Type 2 Diabetes and Varying Levels of Renal Function

    Science.gov (United States)

    Frid, Anders; Sterner, Gunnar N.; Löndahl, Magnus; Wiklander, Clara; Cato, Anne; Vinge, Ellen; Andersson, Anders

    2010-01-01

    OBJECTIVE To study trough levels of metformin in serum and its intra-individual variation in patients using a newly developed assay. RESEARCH DESIGN AND METHODS Trough serum levels of metformin were measured once using liquid chromatography–tandem mass spectrometry (LCMSMS) in 137 type 2 diabetic patients with varying renal function (99 men) and followed repeatedly during 2 months in 20 patients (16 men) with estimated glomerular filtration rate (eGFR) 60, 30–60, and 20 μmol/l. Metformin measurement is less suitable for dose titration. PMID:20215446

  4. Measurement of speech levels in the presence of time varying background noise

    Science.gov (United States)

    Pearsons, K. S.; Horonjeff, R.

    1982-01-01

    Short-term speech level measurements which could be used to note changes in vocal effort in a time varying noise environment were studied. Knowing the changes in speech level would in turn allow prediction of intelligibility in the presence of aircraft flyover noise. Tests indicated that it is possible to use two second samples of speech to estimate long term root mean square speech levels. Other tests were also performed in which people read out loud during aircraft flyover noise. Results of these tests indicate that people do indeed raise their voice during flyovers at a rate of about 3-1/2 dB for each 10 dB increase in background level. This finding is in agreement with other tests of speech levels in the presence of steady state background noise.

  5. Improved Criteria on Delay-Dependent Stability for Discrete-Time Neural Networks with Interval Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    O. M. Kwon

    2012-01-01

    Full Text Available The purpose of this paper is to investigate the delay-dependent stability analysis for discrete-time neural networks with interval time-varying delays. Based on Lyapunov method, improved delay-dependent criteria for the stability of the networks are derived in terms of linear matrix inequalities (LMIs by constructing a suitable Lyapunov-Krasovskii functional and utilizing reciprocally convex approach. Also, a new activation condition which has not been considered in the literature is proposed and utilized for derivation of stability criteria. Two numerical examples are given to illustrate the effectiveness of the proposed method.

  6. Consumer acceptance of model soup system with varying levels of herbs and salt.

    Science.gov (United States)

    Wang, Chao; Lee, Youngsoo; Lee, Soo-Yeun

    2014-10-01

    Although herbs have been reported as one of the most common saltiness enhancers, few studies have focused on the effect of herbs on reducing added sodium as well as the impact of herbs on consumers' overall liking of foods. Therefore, the objectives of this study were to determine the effect of varying levels of herbs on reducing added sodium and consumers' overall liking of soups and identify the impact of salt levels on consumers' overall liking of soups. Overall liking of freshly prepared and retorted canned soups with varying levels of herbs was evaluated before and after adding salt by consumers ad libitum until the saltiness of the soup was just about right for them. The results of the study demonstrated that when the perceived herb flavor increased, the amount of salt consumers added to fresh soups decreased (P ≤ 0.006); however, consumers' overall liking decreased (P ≤ 0.013) as well for the highest level of herb tested in the study. Although overall liking of all canned soups was not significantly decreased by herbs, the amount of salt consumers added was also not significantly decreased when herbs were used. Overall liking of all soups significantly increased after more salt was added (P ≤ 0.001), which indicates that salt level was a dominant factor in affecting consumers' overall liking of soups with varying levels of herbs. These findings imply the role of herbs in decreasing salt intake, and the adequate amount of herbs to be added in soup systems. It is challenging for the food industry to reduce sodium in foods without fully understanding the impact of sodium reduction on sensory properties of foods. Herbs are recommended to use in reducing sodium; however, little has been reported regarding the effect of herbs on sodium reduction and how herbs influence consumers’ acceptance of foods. This study provides findings that herbs may aid in decreasing the amount of salt consumers need to add for freshly prepared soups. It was also found that high

  7. Delay-Dependent Stability Criteria of Uncertain Periodic Switched Recurrent Neural Networks with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Xing Yin

    2011-01-01

    uncertain periodic switched recurrent neural networks with time-varying delays. When uncertain discrete-time recurrent neural network is a periodic system, it is expressed as switched neural network for the finite switching state. Based on the switched quadratic Lyapunov functional approach (SQLF and free-weighting matrix approach (FWM, some linear matrix inequality criteria are found to guarantee the delay-dependent asymptotical stability of these systems. Two examples illustrate the exactness of the proposed criteria.

  8. New delay-dependent absolute stability criteria for Lur'e systems with time-varying delay

    Science.gov (United States)

    Chen, Yonggang; Bi, Weiping; Li, Wenlin

    2011-07-01

    In this article, the absolute stability problem is investigated for Lur'e systems with time-varying delay and sector-bounded nonlinearity. By employing the delay fractioning idea, the new augmented Lyapunov functional is first constructed. Then, by introducing some slack matrices and by reserving the useful term when estimating the upper bound of the derivative of Lyapunov functional, the new delay-dependent absolute stability criteria are derived in terms of linear matrix inequalities. Several numerical examples are presented to show the effectiveness and the less conservativeness of the proposed method.

  9. Time-Varying Market Integration and Expected Returns in Emerging Markets

    OpenAIRE

    de Jong, Frank; de Roon, Frans

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematic risk as measured by their beta relative to the world portfolio as well as on the level of integration in that market. The level of integration is a time-varying variable that depends on the market value of the assets that can be held by domestic investors only versus the market value of the assets that can be traded freely. Our empirical analysis for 30 emerging markets shows that there are stro...

  10. Time Varying Market Integration and Expected Rteurns in Emerging Markets

    OpenAIRE

    Jong, F.C.J.M. de; Roon, F.A. de

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematic risk as measured by their beta relative to the world portfolio as well as on the level of integration in that market.The level of integration is a time-varying variable that depends on the market value of the assets that can be held by domestic investors only versus the market value of the assets that can be traded freely.Our empirical analysis for 30 emerging markets shows that there are strong...

  11. Endocannabinoid and Mood Responses to Exercise in Adults with Varying Activity Levels.

    Science.gov (United States)

    Brellenthin, Angelique G; Crombie, Kevin M; Hillard, Cecilia J; Koltyn, Kelli F

    2017-08-01

    Acute aerobic exercise improves mood and activates the endocannabinoid (eCB) system in physically active individuals; however, both mood and eCB responses to exercise may vary based on habitual levels of physical activity. This study aimed to examine eCB and mood responses to prescribed and preferred exercises among individuals with low, moderate, and high levels of physical activity. Thirty-six healthy adults (21 ± 4 yr) were recruited from low (≤60 min moderate-vigorous physical activity [MVPA] per week), moderate (150-299 min MVPA per week), and high (≥300 MVPA per week) physical activity groups. Participants performed both prescribed (approximately 70%-75% max) and preferred (i.e., self-selected) aerobic exercise on separate days. Mood states and eCB concentrations were assessed before and after exercise conditions. Both preferred and prescribed exercise resulted in significant increases (P exercise elicited positive mood improvements compared with preexercise values, but changes in state anxiety, total mood disturbance, and confusion were greater in the preferred condition (P mood disturbance in the preferred condition (P mood or eCB outcomes. These results indicate that eCB and mood responses to exercise do not differ significantly between samples with varying physical activity levels. This study also demonstrates that in addition to prescribed exercise, preferred exercise activates the eCB system, and this activation may contribute to positive mood outcomes with exercise.

  12. New Delay-Dependent Stability Criteria for Uncertain Neutral Systems with Mixed Time-Varying Delays and Nonlinear Perturbations

    Directory of Open Access Journals (Sweden)

    Hamid Reza Karimi

    2009-01-01

    Full Text Available The problem of stability analysis for a class of neutral systems with mixed time-varying neutral, discrete and distributed delays and nonlinear parameter perturbations is addressed. By introducing a novel Lyapunov-Krasovskii functional and combining the descriptor model transformation, the Leibniz-Newton formula, some free-weighting matrices, and a suitable change of variables, new sufficient conditions are established for the stability of the considered system, which are neutral-delay-dependent, discrete-delay-range-dependent, and distributed-delay-dependent. The conditions are presented in terms of linear matrix inequalities (LMIs and can be efficiently solved using convex programming techniques. Two numerical examples are given to illustrate the efficiency of the proposed method.

  13. Transport methods: general. 2. Monte Carlo Particle Transport in Media with Exponentially Varying Time-Dependent Cross Sections

    International Nuclear Information System (INIS)

    Brown, Forrest B.; Martin, William R.

    2001-01-01

    We have investigated Monte Carlo schemes for analyzing particle transport through media with exponentially varying time-dependent cross sections. For such media, the cross sections are represented in the form Σ(t) = Σ 0 e -at (1) or equivalently as Σ(x) = Σ 0 e -bx (2) where b = av and v is the particle speed. For the following discussion, the parameters a and b may be either positive, for exponentially decreasing cross sections, or negative, for exponentially increasing cross sections. For most time-dependent Monte Carlo applications, the time and spatial variations of the cross-section data are handled by means of a stepwise procedure, holding the cross sections constant for each region over a small time interval Δt, performing the Monte Carlo random walk over the interval Δt, updating the cross sections, and then repeating for a series of time intervals. Continuously varying spatial- or time-dependent cross sections can be treated in a rigorous Monte Carlo fashion using delta-tracking, but inefficiencies may arise if the range of cross-section variation is large. In this paper, we present a new method for sampling collision distances directly for cross sections that vary exponentially in space or time. The method is exact and efficient and has direct application to Monte Carlo radiation transport methods. To verify that the probability density function (PDF) is correct and that the random-sampling procedure yields correct results, numerical experiments were performed using a one-dimensional Monte Carlo code. The physical problem consisted of a beam source impinging on a purely absorbing infinite slab, with a slab thickness of 1 cm and Σ 0 = 1 cm -1 . Monte Carlo calculations with 10 000 particles were run for a range of the exponential parameter b from -5 to +20 cm -1 . Two separate Monte Carlo calculations were run for each choice of b, a continuously varying case using the random-sampling procedures described earlier, and a 'conventional' case where the

  14. Event-Based $H_\\infty $ State Estimation for Time-Varying Stochastic Dynamical Networks With State- and Disturbance-Dependent Noises.

    Science.gov (United States)

    Sheng, Li; Wang, Zidong; Zou, Lei; Alsaadi, Fuad E

    2017-10-01

    In this paper, the event-based finite-horizon H ∞ state estimation problem is investigated for a class of discrete time-varying stochastic dynamical networks with state- and disturbance-dependent noises [also called (x,v) -dependent noises]. An event-triggered scheme is proposed to decrease the frequency of the data transmission between the sensors and the estimator, where the signal is transmitted only when certain conditions are satisfied. The purpose of the problem addressed is to design a time-varying state estimator in order to estimate the network states through available output measurements. By employing the completing-the-square technique and the stochastic analysis approach, sufficient conditions are established to ensure that the error dynamics of the state estimation satisfies a prescribed H ∞ performance constraint over a finite horizon. The desired estimator parameters can be designed via solving coupled backward recursive Riccati difference equations. Finally, a numerical example is exploited to demonstrate the effectiveness of the developed state estimation scheme.

  15. Novel assay of metformin levels in patients with type 2 diabetes and varying levels of renal function: clinical recommendations.

    Science.gov (United States)

    Frid, Anders; Sterner, Gunnar N; Löndahl, Magnus; Wiklander, Clara; Cato, Anne; Vinge, Ellen; Andersson, Anders

    2010-06-01

    To study trough levels of metformin in serum and its intra-individual variation in patients using a newly developed assay. Trough serum levels of metformin were measured once using liquid chromatography-tandem mass spectrometry (LCMSMS) in 137 type 2 diabetic patients with varying renal function (99 men) and followed repeatedly during 2 months in 20 patients (16 men) with estimated glomerular filtration rate (eGFR) 60, 30-60, and 20 micromol/l. Metformin measurement is less suitable for dose titration.

  16. Metabolites Identified during Varied Doses of Aspergillus Species in Zea mays Grains, and Their Correlation with Aflatoxin Levels

    Directory of Open Access Journals (Sweden)

    Titilayo D. O. Falade

    2018-05-01

    Full Text Available Aflatoxin contamination is associated with the development of aflatoxigenic fungi such as Aspergillus flavus and A. parasiticus on food grains. This study was aimed at investigating metabolites produced during fungal development on maize and their correlation with aflatoxin levels. Maize cobs were harvested at R3 (milk, R4 (dough, and R5 (dent stages of maturity. Individual kernels were inoculated in petri dishes with four doses of fungal spores. Fungal colonisation, metabolite profile, and aflatoxin levels were examined. Grain colonisation decreased with kernel maturity: milk-, dough-, and dent-stage kernels by approximately 100%, 60%, and 30% respectively. Aflatoxin levels increased with dose at dough and dent stages. Polar metabolites including alanine, proline, serine, valine, inositol, iso-leucine, sucrose, fructose, trehalose, turanose, mannitol, glycerol, arabitol, inositol, myo-inositol, and some intermediates of the tricarboxylic acid cycle (TCA—also known as citric acid or Krebs cycle were important for dose classification. Important non-polar metabolites included arachidic, palmitic, stearic, 3,4-xylylic, and margaric acids. Aflatoxin levels correlated with levels of several polar metabolites. The strongest positive and negative correlations were with arabitol (R = 0.48 and turanose and (R = −0.53, respectively. Several metabolites were interconnected with the TCA; interconnections of the metabolites with the TCA cycle varied depending upon the grain maturity.

  17. Delay-dependent exponential stability for neural networks with discrete and distributed time-varying delays

    International Nuclear Information System (INIS)

    Zhu Xunlin; Wang Youyi

    2009-01-01

    This Letter studies the exponential stability for a class of neural networks (NNs) with both discrete and distributed time-varying delays. Under weaker assumptions on the activation functions, by defining a more general type of Lyapunov functionals and developing a new convex combination technique, new less conservative and less complex stability criteria are established to guarantee the global exponential stability of the discussed NNs. The obtained conditions are dependent on both discrete and distributed delays, are expressed in terms of linear matrix inequalities (LMIs), and contain fewer decision variables. Numerical examples are given to illustrate the effectiveness and the less conservatism of the proposed conditions.

  18. New Delay-Dependent Robust Exponential Stability Criteria of LPD Neutral Systems with Mixed Time-Varying Delays and Nonlinear Perturbations

    Directory of Open Access Journals (Sweden)

    Sirada Pinjai

    2013-01-01

    Full Text Available This paper is concerned with the problem of robust exponential stability for linear parameter-dependent (LPD neutral systems with mixed time-varying delays and nonlinear perturbations. Based on a new parameter-dependent Lyapunov-Krasovskii functional, Leibniz-Newton formula, decomposition technique of coefficient matrix, free-weighting matrices, Cauchy’s inequality, modified version of Jensen’s inequality, model transformation, and linear matrix inequality technique, new delay-dependent robust exponential stability criteria are established in terms of linear matrix inequalities (LMIs. Numerical examples are given to show the effectiveness and less conservativeness of the proposed methods.

  19. Solution to the monoenergetic time-dependent neutron transport equation with a time-varying source

    International Nuclear Information System (INIS)

    Ganapol, B.D.

    1986-01-01

    Even though fundamental time-dependent neutron transport problems have existed since the inception of neutron transport theory, it has only been recently that a reliable numerical solution to one of the basic problems has been obtained. Experience in generating numerical solutions to time-dependent transport equations has indicated that the multiple collision formulation is the most versatile numerical technique for model problems. The formulation coupled with a moment reconstruction of each collided flux component has led to benchmark-quality (four- to five-digit accuracy) numerical evaluation of the neutron flux in plane infinite geometry for any degree of scattering anisotropy and for both pulsed isotropic and beam sources. As will be shown in this presentation, this solution can serve as a Green's function, thus extending the previous results to more complicated source situations. Here we will be concerned with a time-varying source at the center of an infinite medium. If accurate, such solutions have both pedagogical and practical uses as benchmarks against which other more approximate solutions designed for a wider class of problems can be compared

  20. A delay-dependent approach to robust control for neutral uncertain neural networks with mixed interval time-varying delays

    International Nuclear Information System (INIS)

    Lu, Chien-Yu

    2011-01-01

    This paper considers the problem of delay-dependent global robust stabilization for discrete, distributed and neutral interval time-varying delayed neural networks described by nonlinear delay differential equations of the neutral type. The parameter uncertainties are norm bounded. The activation functions are assumed to be bounded and globally Lipschitz continuous. Using a Lyapunov functional approach and linear matrix inequality (LMI) techniques, the stability criteria for the uncertain neutral neural networks with interval time-varying delays are established in the form of LMIs, which can be readily verified using the standard numerical software. An important feature of the result reported is that all the stability conditions are dependent on the upper and lower bounds of the delays. Another feature of the results lies in that it involves fewer free weighting matrix strategy, and upper bounds of the inner product between two vectors are not introduced to reduce the conservatism of the criteria. Two illustrative examples are provided to demonstrate the effectiveness and the reduced conservatism of the proposed method

  1. Bit-level plane image encryption based on coupled map lattice with time-varying delay

    Science.gov (United States)

    Lv, Xiupin; Liao, Xiaofeng; Yang, Bo

    2018-04-01

    Most of the existing image encryption algorithms had two basic properties: confusion and diffusion in a pixel-level plane based on various chaotic systems. Actually, permutation in a pixel-level plane could not change the statistical characteristics of an image, and many of the existing color image encryption schemes utilized the same method to encrypt R, G and B components, which means that the three color components of a color image are processed three times independently. Additionally, dynamical performance of a single chaotic system degrades greatly with finite precisions in computer simulations. In this paper, a novel coupled map lattice with time-varying delay therefore is applied in color images bit-level plane encryption to solve the above issues. Spatiotemporal chaotic system with both much longer period in digitalization and much excellent performances in cryptography is recommended. Time-varying delay embedded in coupled map lattice enhances dynamical behaviors of the system. Bit-level plane image encryption algorithm has greatly reduced the statistical characteristics of an image through the scrambling processing. The R, G and B components cross and mix with one another, which reduces the correlation among the three components. Finally, simulations are carried out and all the experimental results illustrate that the proposed image encryption algorithm is highly secure, and at the same time, also demonstrates superior performance.

  2. Corticosterone profiles in northern cardinals (Cardinalis cardinalis): Do levels vary through life history stages?

    Science.gov (United States)

    Duckworth, Benjamin M; Jawor, Jodie M

    2018-04-17

    As animals move through life history stages, energy requirements for each stage will vary. Both daily and annual variation in the glucocoriticoid hormones (specifically corticosterone, or CORT, in birds) helps provide the variable energy needed through life history stages. In many bird species, CORT is higher in the breeding season when energy demands can be quite high and is often lower in the non-breeding season. Additionally, CORT has a role to play in the response to stressful stimuli and the level to which CORT is elevated following stressful events can vary through the annual cycle as well. Here we report on baseline and stress-induced CORT levels in both sexes of northern cardinals, Cardinalis cardinalis, a non-migrating, year-round territorial species across life history stages. Corticosterone is overall higher in the non-breeding season than the breeding season in both sexes. Males tend to have higher levels of stress-induced CORT than females, although the observed patterns are complex. Our findings differ from one of the more common profile reported in songbirds where breeding season CORT tends to be higher than non-breeding levels. A strong influence may be the prolonged breeding season seen in cardinals; lower levels of CORT during breeding may guard against adverse maternal effects, interruptions in breeding behaviors, or egg production. Additional investigation of species with similar ecologies to northern cardinals, and more populations of cardinals, may show that annual glucocorticoid profiles are more labile than previously appreciated. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. The levels of triglyceride and total cholesterol in methamphetamine dependence.

    Science.gov (United States)

    Zhang, Meijuan; Lv, Dezhao; Zhou, Wu; Ji, Lili; Zhou, Beibei; Chen, Han; Gu, Yingying; Zhao, Jiyun; He, Jincai

    2017-04-01

    The serum triglyceride (TG) and total cholesterol (TC) levels have been reported altered in the traditional drug-dependence (such as marijuana and heroin). However, studies assessing the relationships among serum TC, TG, and methamphetamine (MA)-dependence have not been described well. In this study, our aim is to explore the serum TG and TC levels in large sample of MA-dependent patients. A retrospective study was conducted in 938 MA-dependent patients who were recruited between February 2, 2008 and March 11, 2013, with social characteristics and drug-dependence history (duration of MA use, routes of drug administration, and daily dose were collected). Then, the serum levels of TC, TG, glucose (GLU), body mass index (BMI), and blood pressure were measured among the participants. Meanwhile, 985 age- and gender-matched healthy people in the physical examination center were selected as control group. Compared with the control group, significant decreases of TC, TG, GLU, and BMI were observed in MA-dependent patients (P < 0.05). Besides, we found that the daily dose of MA use was associated with TC (β = -0.079, P = 0.015) and the duration of MA use was independently related to BMI (β = -0.071, P = 0.031). This study demonstrated that the levels of TC, TG, GLU, and BMI factors altered in the MA-dependent patients. In addition, there is a negative association between MA dependence and TC and BMI.

  4. Muscle utilization patterns vary by skill levels of the practitioners across specific yoga poses (asanas).

    Science.gov (United States)

    Ni, Meng; Mooney, Kiersten; Balachandran, Anoop; Richards, Luca; Harriell, Kysha; Signorile, Joseph F

    2014-08-01

    To compare muscle activation patterns in 14 dominant side muscles during different yoga poses across three skill levels. Mixed repeated-measures descriptive study. University neuromuscular research laboratory, Miami, US. A group of 36 yoga practitioners (9 M/27 F; mean ± SD, 31.6 ± 12.6 years) with at least 3 months yoga practice experience. Each of the 11 surya namaskar poses A and B was performed separately for 15s and the surface electromyography for 14 muscles were recorded. Normalized root mean square of the electromyographic signal (NrmsEMG) for 14 muscles (5 upper body, 4 trunk, 5 lower body). There were significant main effects of pose for all fourteen muscles except middle trapezius (p<.02) and of skill level for the vastus medialis; p=.027). A significant skill level × pose interaction existed for five muscles (pectoralis major sternal head, anterior deltoid, medial deltoid, upper rectus abdominis and gastrocnemius lateralis; p<.05). Post hoc analyses using Bonferroni comparisons indicated that different poses activated specific muscle groups; however, this varied by skill level. Our results indicate that different poses can produce specific muscle activation patterns which may vary due to practitioners' skill levels. This information can be used in designing rehabilitation and training programs and for cuing during yoga training. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. The hippocampal response to psychosocial stress varies with salivary uric acid level

    Science.gov (United States)

    Goodman, Adam M.; Wheelock, Muriah D.; Harnett, Nathaniel G.; Mrug, Sylvie; Granger, Douglas A.; Knight, David C.

    2016-01-01

    Uric acid is a naturally occurring, endogenous compound that impacts mental health. In particular, uric acid levels are associated with emotion-related psychopathology (e.g., anxiety and depression). Therefore, understanding uric acid’s impact on the brain would provide valuable new knowledge regarding neural mechanisms that mediate the relationship between uric acid and mental health. Brain regions including the prefrontal cortex, amygdala, and hippocampus underlie stress reactivity and emotion regulation. Thus, uric acid may impact emotion by modifying the function of these brain regions. The present study used functional magnetic resonance imaging (fMRI) during a psychosocial stress task to investigate the relationship between baseline uric acid levels (in saliva) and brain function. Results demonstrate that activity within the bilateral hippocampal complex varied with uric acid concentrations. Specifically, activity within the hippocampus and surrounding cortex increased as a function of uric acid level. The current findings suggest that uric acid levels modulate stress-related hippocampal activity. Given that the hippocampus has been implicated in emotion regulation during psychosocial stress, the present findings offer a potential mechanism by which uric acid impacts mental health. PMID:27725214

  6. The hippocampal response to psychosocial stress varies with salivary uric acid level.

    Science.gov (United States)

    Goodman, Adam M; Wheelock, Muriah D; Harnett, Nathaniel G; Mrug, Sylvie; Granger, Douglas A; Knight, David C

    2016-12-17

    Uric acid is a naturally occurring, endogenous compound that impacts mental health. In particular, uric acid levels are associated with emotion-related psychopathology (e.g., anxiety and depression). Therefore, understanding uric acid's impact on the brain would provide valuable new knowledge regarding neural mechanisms that mediate the relationship between uric acid and mental health. Brain regions including the prefrontal cortex, amygdala, and hippocampus underlie stress reactivity and emotion regulation. Thus, uric acid may impact emotion by modifying the function of these brain regions. The present study used functional magnetic resonance imaging (fMRI) during a psychosocial stress task to investigate the relationship between baseline uric acid levels (in saliva) and brain function. Results demonstrate that activity within the bilateral hippocampal complex varied with uric acid concentrations. Specifically, activity within the hippocampus and surrounding cortex increased as a function of uric acid level. The current findings suggest that uric acid levels modulate stress-related hippocampal activity. Given that the hippocampus has been implicated in emotion regulation during psychosocial stress, the present findings offer a potential mechanism by which uric acid impacts mental health. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. The stress-reducing effect of music listening varies depending on the social context.

    Science.gov (United States)

    Linnemann, Alexandra; Strahler, Jana; Nater, Urs M

    2016-10-01

    Given that music listening often occurs in a social context, and given that social support can be associated with a stress-reducing effect, it was tested whether the mere presence of others while listening to music enhances the stress-reducing effect of listening to music. A total of 53 participants responded to questions on stress, presence of others, and music listening five times per day (30min after awakening, 1100h, 1400h, 1800h, 2100h) for seven consecutive days. After each assessment, participants were asked to collect a saliva sample for the later analysis of salivary cortisol (as a marker for the hypothalamic-pituitary-adrenal axis) and salivary alpha-amylase (as a marker for the autonomic nervous system). Hierarchical linear modeling revealed that music listening per se was not associated with a stress-reducing effect. However, listening to music in the presence of others led to decreased subjective stress levels, attenuated secretion of salivary cortisol, and higher activity of salivary alpha-amylase. When listening to music alone, music that was listened to for the reason of relaxation predicted lower subjective stress. The stress-reducing effect of music listening in daily life varies depending on the presence of others. Music listening in the presence of others enhanced the stress-reducing effect of music listening independently of reasons for music listening. Solitary music listening was stress-reducing when relaxation was stated as the reason for music listening. Thus, in daily life, music listening can be used for stress reduction purposes, with the greatest success when it occurs in the presence of others or when it is deliberately listened to for the reason of relaxation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Study of nuclear level density parameter and its temperature dependence

    International Nuclear Information System (INIS)

    Nasrabadi, M. N.; Behkami, A. N.

    2000-01-01

    The nuclear level density ρ is the basic ingredient required for theoretical studies of nuclear reaction and structure. It describes the statistical nuclear properties and is expressed as a function of various constants of motion such as number of particles, excitation energy and angular momentum. In this work the energy and spin dependence of nuclear level density will be presented and discussed. In addition the level density parameter α will be extracted from this level density information, and its temperature and mass dependence will be obtained

  9. Anaerobic nitrogen turnover by sinking diatom aggregates at varying ambient oxygen levels

    DEFF Research Database (Denmark)

    Stief, Peter; Kamp, Anja; Thamdrup, Bo

    2016-01-01

    nitrate supply. Sinking diatom aggregates can contribute directly to fixed-nitrogen loss in low-oxygen environments in the ocean and vastly expand the ocean volume in which anaerobic nitrogen turnover is possible, despite relatively high ambient oxygen levels. Depending on the extent of intracellular......In the world’s oceans, even relatively low oxygen levels inhibit anaerobic nitrogen cycling by free-living microbes. Sinking organic aggregates, however, might provide oxygen-depleted microbial hotspots in otherwise oxygenated surface waters. Here, we show that sinking diatom aggregates can host...

  10. SERUM ACETYLCHOLINESTERASE LEVEL IN THE PATIENTS OF OPIOID (BROWN SUGAR) DEPENDENCE

    OpenAIRE

    Shah, Nilesh; Dave, Kirti

    1992-01-01

    The authors compared the serum acetylcholinesterase level in the patients of brown sugar dependence and the normal volunteers. Significantly lower level of serum acetylcholinesterase was found in patients of brown sugar dependence.

  11. A Temperature-Dependent Thermal Model of IGBT Modules Suitable for Circuit-Level Simulations

    DEFF Research Database (Denmark)

    Wu, Rui; Wang, Huai; Ma, Ke

    2014-01-01

    Thermal impedance of IGBT modules may vary with operating conditions due to that the thermal conductivity and heat capacity of materials are temperature dependent. This paper proposes a Cauer thermal model for a 1700 V/1000 A IGBT module with temperature-dependent thermal resistances and thermal ...... relevant reliability aspect performance. A test bench is built up with an ultra-fast infrared (IR) camera to validate the proposed thermal impedance model....

  12. Social, state-dependent and environmental modulation of faecal corticosteroid levels in free-ranging female spotted hyenas.

    Science.gov (United States)

    Goymann, W; East, M L; Wachter, B; Höner, O P; Möstl, E; Van't Hof, T J; Hofer, H

    2001-12-07

    Little is known about to what extent the sensitivity of the hypothalamic-pituitary-adrenal (HPA) axis may be state dependent and vary in the same species between environments. Here we tested whether the faecal corticosteroid concentrations of matrilineal adult female spotted hyenas are influenced by social and reproductive status in adjacent ecosystems and whether they vary between periods with and without social stress. Females in the Serengeti National Park frequently become socially subordinate intruders in other hyena territories by undertaking long-distance foraging trips to migratory herds, whereas in the Ngorongoro Crater they usually forage inside their own small territories on resident prey. The faecal corticosteroid concentrations in Serengeti females were significantly higher than in Ngorongoro females. Energy expenditure by lactation is exceptionally high in spotted hyenas and this may be reflected in their corticosteroid levels. The faecal corticosteroid levels in both populations were higher in lactating than in non-lactating females. During periods of social stability, faecal corticosteroid concentrations increased in non-lactating females but not in lactating females as social status declined. Lactating Serengeti females had significantly higher faecal corticosteroid concentrations during periods with acute severe social stress than during periods without, indicating that the HPA axis is sensitive to social stimuli even in lactating females. So far few studies have used non-invasive monitoring methods for assessing social stress in freeranging animals. This study demonstrates for the first time, to the authors' knowledge, that corticosteroid concentrations may differ between periods with and without social stress for a free-ranging female mammal and that the modulating effect of social status may depend on reproductive status.

  13. Size stratification in a Gilbert delta due to a varying base level: flume experiments.

    Science.gov (United States)

    Chavarrias, Victor; Orru, Clara; Viparelli, Enrica; Vide, Juan Pedro Martin; Blom, Astrid

    2014-05-01

    A foreset-dominated Gilbert delta is a delta that is dominated by sediment avalanches (i.e., discontinuous grain flows) over its front. It forms when a river flows into a basin or sea characterized by a flow depth that is much larger than the one in the fluvial reach, and the conditions are such that the transported sediment passing the brinkpoint forms a wedge at the topmost part of the foreset, which results in avalanches down the foreset and a fining upward pattern within the foreset deposit. A Gilbert delta is typically described in terms of a low-slope topset (resulting from deposition over the fluvial reach), a steep-slope foreset (resulting from sediment avalanches over the lee face), and a bottomset (resulting from deposition of fine sediment passing the brinkpoint as suspended load). The objective of the present study is to gain insight into the mechanisms taking part in Gilbert delta formation and progradation under variable base level conditions. In order to do so, three flume experiments were conducted in which the water discharge and sediment feed rate were maintained constant but the base level varied between the experiments: (I) constant base level, (II) a gradually rising base level, and (III) a slowly varying base level. The stratigraphy within the delta deposit was measured using image analysis combined with particle coloring. A steady base level resulted in aggradation over the fluvial reach in order to maintain a slope required to transport the supplied sediment downstream. Sea level rise enhanced the amount of aggradation over the fluvial reach due to the presence of an M1 backwater curve. The aggrading flux to the substrate was slightly coarser than the fed sediment. The sediment at the base of the foreset deposit appeared to become coarser in streamwise direction. Eventually, a fall of the base level induced an M2 backwater curve over the fluvial reach that caused degradation of the fluvial reach. Base level fall first induced erosion of the

  14. Central Cardiovascular Responses of Quadriplegic Subjects to Arm Exercise at Varying Levels of Oxygen Uptake.

    Science.gov (United States)

    Figoni, Stephen F.

    The purpose of this study was to assess selected central cardiovascular functions of spinal cord injured, quadriplegic subjects at varying levels of oxygen uptake (VO sub 2). Subjects included 11 untrained, male college students with C5, C6, or C7 complete quadriplegia and 11 able-bodied reference subjects. Exercise was performed on a Monark cycle…

  15. Mycorrhizal dependency of mangaba tree under increasing phosphorus levels Dependência micorrízica de mangabeira em doses crescentes de fósforo

    Directory of Open Access Journals (Sweden)

    Júlio Alves Cardoso Filho

    2008-07-01

    Full Text Available The objective of this study was to evaluate the mycorrhizal dependency of mangaba tree (Hancornia speciosa plantlets, under increasing levels of phosphorus fertilization. The experimental design was completely randomized in a 4×5 factorial arrangement with three mycorrhizal fungi inocula - Gigaspora margarita, Glomus etunicatum, or a pool of native mycorrhizal fungi (Acaulospora longula, Glomus clarum, Gigaspora albida, Paraglomus sp. -, and a nonmycorrhizal control, in combination with five levels of phosphorus applied to the substrate: 0, 25, 50, 75, and 100 mg kg-1. After 180 days of growth, plantlets with inoculation of native mycorrhizal pool produced more shoot and root dry biomass and had higher shoot phosphorus content and accumulation. The noninoculated control showed the lowest values, independently of the phosphorus level. The highest relative mycorrhizal dependency occurred with the inoculation of native mycorrhizal fungi. Plants with mycorrhizal fungi did not respond to phosphorus addition above 50 mg kg-1. Mangaba tree is highly dependent on mycorrhiza, but the degree of dependency varies according to phosphorus levels and fungal inocula. In general, mangaba tree is more responsive to mycorrhizal fungi inoculation than to phosphorus addition.O objetivo deste trabalho foi avaliar a dependência micorrízica de mudas de mangaba (Hancornia speciosa, em doses crescentes de fósforo. O delineamento experimental foi inteiramente casualizado, em arranjo fatorial 4´5 com três inóculos de fungos micorrízicos - Gigaspora margarita, Glomus etunicatum, ou uma mistura de espécies de fungos micorrízicos nativos (Acaulospora longula, Glomus clarum, Gigaspora albida e Paraglomus sp. -, e um controle não micorrízico, combinados a cinco doses de fósforo no substrato: 0, 25, 50, 75 e 100 mg kg-1. Após 180 dias, as mudas com inoculação dos fungos micorrízicos nativos produziram mais biomassa seca de parte aérea e raízes e apresentaram

  16. Effect of temperature-dependent energy-level shifts on a semiconductor's Peltier heat

    International Nuclear Information System (INIS)

    Emin, D.

    1984-01-01

    The Peltier heat of a charge carrier in a semiconductor is calculated for the situation in which the electronic energy levels are temperature dependent. The temperature dependences of the electronic energy levels, generally observed optically, arise from their dependences on the vibrational energy of the lattice (e.g., as caused by thermal expansion). It has been suggested that these temperature dependences will typically have a major effect on the Peltier heat. The Peltier heat associated with a given energy level is a thermodynamic quantity; it is the product of the temperature and the change of the entropy of the system when a carrier is added in that level. As such, the energy levels cannot be treated as explicitly temperature dependent. The electron-lattice interaction causing the temperature dependence must be expressly considered. It is found that the carrier's interaction with the atomic vibrations lowers its electronic energy. However, the interaction of the carrier with the atomic vibrations also causes an infinitesimal lowering (approx.1/N) of each of the N vibrational frequencies. As a result, there is a finite carrier-induced increase in the average vibrational energy. Above the Debye temperature, this cancels the lowering of the carrier's electronic energy. Thus, the standard Peltier-heat formula, whose derivation generally ignores the temperature dependence of the electronic energy levels, is regained. This explains the apparent success of the standard formula in numerous analyses of electronic transport experiments

  17. Noise level estimation in weakly nonlinear slowly time-varying systems

    International Nuclear Information System (INIS)

    Aerts, J R M; Dirckx, J J J; Lataire, J; Pintelon, R

    2008-01-01

    Recently, a method using multisine excitation was proposed for estimating the frequency response, the nonlinear distortions and the disturbing noise of weakly nonlinear time-invariant systems. This method has been demonstrated on the measurement of nonlinear distortions in the vibration of acoustically driven systems such as a latex membrane, which is a good example of a time-invariant system [1]. However, not all systems are perfectly time invariant, e.g. biomechanical systems. This time variation can be misinterpreted as an elevated noise floor, and the classical noise estimation method gives a wrong result. Two improved methods to retrieve the correct noise information from the measurements are presented. Both of them make use of multisine excitations. First, it is demonstrated that the improved methods give the same result as the classical noise estimation method when applied to a time-invariant system (high-quality microphone membrane). Next, it is demonstrated that the new methods clearly give an improved estimate of the noise level on time-varying systems. As an application example results for the vibration response of an eardrum are shown

  18. Delay-Range-Dependent H∞ Control for Automatic Mooring Positioning System with Time-Varying Input Delay

    Directory of Open Access Journals (Sweden)

    Xiaoyu Su

    2014-01-01

    Full Text Available Aiming at the economy and security of the positioning system in semi-submersible platform, the paper presents a new scheme based on the mooring line switching strategy. Considering the input delay in switching process, H∞ control with time-varying input delay is designed to calculate the control forces to resist disturbing forces. In order to reduce the conservativeness, the information of the lower bound of delay is taken into account, and a Lyapunov function which contains the range of delay is constructed. Besides, the input constraint is considered to avoid breakage of mooring lines. The sufficient conditions for delay-range-dependent stabilization are derived in terms of LMI, and the controller is also obtained. The effectiveness of the proposed approach is illustrated by a realistic design example.

  19. Excitation energy and angular momentum dependence of the nuclear level densities

    International Nuclear Information System (INIS)

    Razavi, R.; Kakavand, T.; Behkami, A. N.

    2007-01-01

    We have investigated the excitation energy (E) dependence of nuclear level density for Bethe formula and constant temperature model. The level density parameter aa nd the back shifted energy from the Bethe formula are obtained by fitting the complete level schemes. Also the level density parameters from the constant temperature model have been determined for several nuclei. we have shown that the microscopic theory provides more precise information on the nuclear level densities. On the other hand, the spin cut-off parameter and effective moment of inertia are determined by studying of the angular momentum (J) dependence of the nuclear level density, and effective moment of inertia is compared with rigid body value.

  20. A delay-dependent LMI approach to dynamics analysis of discrete-time recurrent neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Song, Qiankun; Wang, Zidong

    2007-01-01

    In this Letter, the analysis problem for the existence and stability of periodic solutions is investigated for a class of general discrete-time recurrent neural networks with time-varying delays. For the neural networks under study, a generalized activation function is considered, and the traditional assumptions on the boundedness, monotony and differentiability of the activation functions are removed. By employing the latest free-weighting matrix method, an appropriate Lyapunov-Krasovskii functional is constructed and several sufficient conditions are established to ensure the existence, uniqueness, and globally exponential stability of the periodic solution for the addressed neural network. The conditions are dependent on both the lower bound and upper bound of the time-varying time delays. Furthermore, the conditions are expressed in terms of the linear matrix inequalities (LMIs), which can be checked numerically using the effective LMI toolbox in MATLAB. Two simulation examples are given to show the effectiveness and less conservatism of the proposed criteria

  1. Recalled first reactions to inhaling nicotine predict the level of physical dependence.

    Science.gov (United States)

    Wellman, Robert J; DiFranza, Joseph R; O'Loughlin, Jennifer

    2014-10-01

    The level of physical dependence is a measure of addiction that correlates highly with addiction-associated changes in brain structure. We sought to determine whether age at first inhalation and initial reactions to inhaling nicotine are related to level of physical dependence in early adulthood. Young adults (n=312; mean age=24 years; 51% female) from the Nicotine Dependence in Teens study who had smoked at least once in the preceding three months completed self-report questionnaires in 2011-12. We assessed level of physical dependence with three validated self-report items assessing 'wanting,' 'craving' and 'needing' triggered by nicotine deprivation. Survey items assessed smoking behavior, including age at first inhalation, and recalled first reactions to inhaling nicotine. After adjusting for covariates, experiencing relaxation, heart racing/pounding, rush or "buzz" (OR=1.45; 95% CI: 1.08, 1.94) and dizziness (OR=1.58; 95% CI: 1.15, 2.18) at first nicotine inhalation were associated with an increased odds of being at a higher level of physical dependence in young adulthood; the association for experiencing relaxation (OR=1.78; 95% CI: 1.20, 2.64) and heart racing/pounding (OR=1.51; 95% CI: 1.00, 2.28) persisted after additionally controlling for all other first reactions. Neither age at first inhalation nor unpleasant first reactions predicted level of physical dependence. In accordance with prior research, our findings suggest that smokers who are particularly sensitive to the pleasant, "buzz-related" and generally arousing effects of nicotine may be more likely to attain higher levels of physical dependence. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Time-varying Crash Risk

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

    We estimate a continuous-time model with stochastic volatility and dynamic crash probability for the S&P 500 index and find that market illiquidity dominates other factors in explaining the stock market crash risk. While the crash probability is time-varying, its dynamic depends only weakly on re...

  3. Parity dependence of the nuclear level density at high excitation

    International Nuclear Information System (INIS)

    Rao, B.V.; Agrawal, H.M.

    1995-01-01

    The basic underlying assumption ρ(l+1, J)=ρ(l, J) in the level density function ρ(U, J, π) has been checked on the basis of high quality data available on individual resonance parameters (E 0 , Γ n , J π ) for s- and p-wave neutrons in contrast to the earlier analysis where information about p-wave resonance parameters was meagre. The missing level estimator based on the partial integration over a Porter-Thomas distribution of neutron reduced widths and the Dyson-Mehta Δ 3 statistic for the level spacing have been used to ascertain that the s- and p-wave resonance level spacings D(0) and D(1) are not in error because of spurious and missing levels. The present work does not validate the tacit assumption ρ(l+1, J)=ρ(l, J) and confirms that the level density depends upon parity at high excitation. The possible implications of the parity dependence of the level density on the results of statistical model calculations of nuclear reaction cross sections as well as on pre-compound emission have been emphasized. (orig.)

  4. Evaluating nicotine dependence levels in e-cigarette users.

    Science.gov (United States)

    González Roz, Alba; Secades Villa, Roberto; Weidberg, Sara

    2017-01-11

    Despite the fact that electronic cigarettes (e-cigarettes) are rapidly growing in popularity and use worldwide, there is scarce scientific data on abuse liability among e-cigarette users, and about whether e-cigarette use is related to nicotine dependence or not. The aim of this study is to explore nicotine dependence levels in a sample of experienced e-cigarette users (n= 39) and to compare them with current tobacco cigarette smokers (n=42). We conducted several face-to-face interviews in order to assess sociodemographic and dependence related characteristics in both e-cigarette users and in smokers. Adapted versions of both the Fagerström test for nicotine dependence (FTND) and the nicotine dependence syndrome scale (NDSS) were used to analyze nicotine dependence in each of the groups. Biochemical markers of carbon monoxide and urinary cotinine analysis were also collected. Results showed that e-cigarette users scored lower than cigarette smokers in both FTND and all NDSS subscales. Our findings extend previous research on e-cigarette use and nicotine addiction and suggest that e-cigarette users are less dependent on nicotine than current tobacco cigarette smokers. Further prospective studies are needed to better ascertain their addictiveness potential, comparing those smokers who switched to e-cigarettes from smoking cigarettes, and those who had never been tobacco cigarette smokers.

  5. Operational Principle of Water Level Detector for Agricultural and ...

    African Journals Online (AJOL)

    This paper proposes a design to automatically detect the level of water in a reservoir (storage tank) at a preset level and initializes an information to the users in case of low water level. The functionality of this sensor depends basically on the electrical conductivity of water (probes) which varies, depending on the level of its ...

  6. Upper Limb Asymmetry in the Sense of Effort Is Dependent on Force Level

    Directory of Open Access Journals (Sweden)

    Diane E. Adamo

    2017-04-01

    Full Text Available Previous studies have shown that asymmetries in upper limb sensorimotor function are dependent on the source of sensory and motor information, hand preference and differences in hand strength. Further, the utilization of sensory and motor information and the mode of control of force may differ between the right hand/left hemisphere and left hand/right hemisphere systems. To more clearly understand the unique contribution of hand strength and intrinsic differences to the control of grasp force, we investigated hand/hemisphere differences when the source of force information was encoded at two different force levels corresponding to a 20 and 70% maximum voluntary contraction or the right and left hand of each participant. Eleven, adult males who demonstrated a stronger right than left maximum grasp force were requested to match a right or left hand 20 or 70% maximal voluntary contraction reference force with the opposite hand. During the matching task, visual feedback corresponding to the production of the reference force was available and then removed when the contralateral hand performed the match. The matching relative force error was significantly different between hands for the 70% MVC reference force but not for the 20% MVC reference force. Directional asymmetries, quantified as the matching force constant error, showed right hand overshoots and left undershoots were force dependent and primarily due to greater undershoots when matching with the left hand the right hand reference force. Findings further suggest that the interaction between internal sources of information, such as efferent copy and proprioception, as well as hand strength differences appear to be hand/hemisphere system dependent. Investigations of force matching tasks under conditions whereby force level is varied and visual feedback of the reference force is available provides critical baseline information for building effective interventions for asymmetric (stroke

  7. Effects of varying levels of n-6:n-3 fatty acid ratio on plasma fatty acid ...

    African Journals Online (AJOL)

    This study investigated the effects of varying dietary levels of n-6:n-3 fatty acid ratio on plasma fatty acid composition and prostanoid synthesis in pregnant rats. Four groups consisting of seven rats per group of non pregnant rats were fed diets with either a very low n-6:n-3 ratio of 50% soybean oil (SBO): 50% cod liver oil ...

  8. Operator dependency of the radiation exposure in cardiac interventions: feasibility of ultra low dose levels

    International Nuclear Information System (INIS)

    Emre Ozpelit, Mehmet; Ercan, Ertugrul; Pekel, Nihat; Tengiz, Istemihan; Yilmaz, Akar; Ozpelit, Ebru; Ozyurtlu, Ferhat

    2017-01-01

    Introduction: Mean radiation exposure in invasive cardiology varies greatly between different centres and interventionists. The International Commission on Radiological Protection and the EURATOM Council stipulate that, despite reference values, 'All medical exposure for radiodiagnostic purposes shall be kept as low as reasonably achievable' (ALARA). The purpose of this study is to establish the effects of the routine application of ALARA principles and to determine operator and procedure impact on radiation exposure in interventional cardiology. Materials and methods: A total of 240 consecutive cardiac interventional procedures were analysed. Five operators performed the procedures, two of whom were working in accordance with ALARA principles (Group 1 operators) with the remaining three working in a standard manner (Group 2 operators). Radiation exposure levels of these two groups were compared. Results: Total fluoroscopy time and the number of radiographic runs were similar between groups. However, dose area product and cumulative dose were significantly lower in Group 1 when compared with Group 2. Radiation levels of Group 1 were far below even the reference levels in the literature, thus representing an ultra-low-dose radiation exposure in interventional cardiology. Conclusion: By use of simple radiation reducing techniques, ultra-low-dose radiation exposure is feasible in interventional cardiology. Achievability of such levels depends greatly on operator awareness, desire, knowledge and experience of radiation protection. (authors)

  9. Time-varying extreme value dependence with application to leading European stock markets

    KAUST Repository

    Castro-Camilo, Daniela; de Carvalho, Miguel; Wadsworth, Jennifer

    2018-01-01

    Extremal dependence between international stock markets is of particular interest in today’s global financial landscape. However, previous studies have shown this dependence is not necessarily stationary over time. We concern ourselves with modeling extreme value dependence when that dependence is changing over time, or other suitable covariate. Working within a framework of asymptotic dependence, we introduce a regression model for the angular density of a bivariate extreme value distribution that allows us to assess how extremal dependence evolves over a covariate. We apply the proposed model to assess the dynamics governing extremal dependence of some leading European stock markets over the last three decades, and find evidence of an increase in extremal dependence over recent years.

  10. Time-varying extreme value dependence with application to leading European stock markets

    KAUST Repository

    Castro-Camilo, Daniela

    2018-03-09

    Extremal dependence between international stock markets is of particular interest in today’s global financial landscape. However, previous studies have shown this dependence is not necessarily stationary over time. We concern ourselves with modeling extreme value dependence when that dependence is changing over time, or other suitable covariate. Working within a framework of asymptotic dependence, we introduce a regression model for the angular density of a bivariate extreme value distribution that allows us to assess how extremal dependence evolves over a covariate. We apply the proposed model to assess the dynamics governing extremal dependence of some leading European stock markets over the last three decades, and find evidence of an increase in extremal dependence over recent years.

  11. Gas Exchange Characteristics in Tectona grandis L. Clones under Varying Concentrations of CO2 Levels

    Directory of Open Access Journals (Sweden)

    S. Saravanan

    2014-08-01

    Full Text Available The Institute of Forest Genetics and Tree Breeding, Coimbatore, India functioning under the Indian Council of Forestry Research and Education, Dehara Dun, has a long term systematic tree improvement program for Tectona grandis aimed to enhancing productivity and screening of clones for site specific. In the process, twenty clones of T. grandis L. were studied for the physiological parameters and water use efficiency with reference to the elevated CO2 levels. CO2 enrichment studies in special chambers help in understanding the changes at individual level, and also at physiological, biochemical and genetic level. It also provides valuable information for establishing plantations at different geographic locations. Considerable variations were observed when the selected 20 clones of T. grandis were subjected to physiological studies under elevated CO2 conditions (600 and 900 mol mol-1. Eight clones exhibited superior growth coupled with favorable physiological characteristics including high photosynthetic rate, carboxylation and water use efficiency under elevated CO2 levels. Clones with minimal variation in physiological characteristics under elevated levels of CO2 suggest their ability to overcome physiological stresses and adapt to varying climatic conditions.

  12. Long-range dependence and sea level forecasting

    CERN Document Server

    Ercan, Ali; Abbasov, Rovshan K

    2013-01-01

    This study shows that the Caspian Sea level time series possess long range dependence even after removing linear trends, based on analyses of the Hurst statistic, the sample autocorrelation functions, and the periodogram of the series. Forecasting performance of ARMA, ARIMA, ARFIMA and Trend Line-ARFIMA (TL-ARFIMA) combination models are investigated. The forecast confidence bands and the forecast updating methodology, provided for ARIMA models in the literature, are modified for the ARFIMA models. Sample autocorrelation functions are utilized to estimate the differencing lengths of the ARFIMA

  13. The dependence level analysis between the human actions in NPP Operation

    International Nuclear Information System (INIS)

    Farcasiu, M.; Nitoi, M.; Apostol, M.; Florescu, G.; Prisecaru, Ilie

    2009-01-01

    The Human Reliability Analysis (HRA) is an important method in Probabilistic Safety Assessment (PSA) studies and offers desirability for concrete improvement of the man - machine - organization interfaces, reliability and safety. An important step in HRA is the dependence level analysis between the human actions performed by the same person or between the actions performed by different persons, step in quantitative analysis of the human errors probabilities. The purpose of this paper is to develop a model to analyze the dependence level between human actions for Nuclear Power Plant (NPP) operation. The model estimates the conditional human error probabilities (CHEP) and joint human error probabilities (JHEP). The achieved sensitivity analyses determine human performance sensibility to systematic variations for dependence level between human actions. The human error probabilities estimated in this paper are adequate values for integration both in HRA and in PSA realized for NPP. This type of analysis helps in finding and analyzing the ways of reducing the likelihood of human errors, so that the impact of human factor to systems availability, reliability and safety can be realistically estimated. In order to demonstrate the usability of this model an analysis is performed upon the dependences between the necessary human actions in mitigating the consequences of LOCA events, particularly for the case of Cernavoda NPP. (authors)

  14. Nutrient Partitioning and Stoichiometry in Unburnt Sugarcane Ratoon at Varying Yield Levels

    Directory of Open Access Journals (Sweden)

    José Marcos Leite

    2016-04-01

    Full Text Available Unraveling nutrient imbalances in contemporary agriculture is a research priority to improve whenever possible yield and nutrient use efficiency in sugarcane (Saccharum spp. systems while minimizing the costs of cultivation (e.g., use of fertilizers and environmental concerns. The main goal of this study was therefore to investigate biomass and nutrient [nitrogen (N, phosphorus (P, and potassium (K] content, partitioning, stoichiometry and internal efficiencies in sugarcane ratoon at varying yield levels. Three sites were established on highly weathered tropical soils located in the Southeast region of Brazil. At all sites, seasonal biomass and nutrient uptake patterns were synthesized from four sampling times taken throughout the sugarcane ratoon season. At all sites, in-season nutrient partitioning (in diverse plant components, internal efficiencies (yield to nutrient content ratio and nutrient ratios (N:P and N:K were determined at harvesting. Sugarcane exhibited three distinct phases of plant growth, as follows: lag, exponential-linear, and stationary. Across sites, nutrient requirement per unit of yield was 1.4 kg N, 0.24 kg P, and 2.7 kg K per Mg of stalk produced, but nutrient removal varied with soil nutrient status (based on soil plus fertilizer nutrient supply and crop demand (potential yield. Dry leaves had lower nutrient content (N, P, and K and broader N:P and N:K ratios when compared with tops and stalks plant fractions. Greater sugarcane yield and narrowed N:P ratio (6:1 were verified for tops of sugarcane when increasing both N and P content. High-yielding sugarcane systems were related to higher nutrient content and more balanced N:P (6:1 and N:K (0.5:1 ratios.

  15. Dependence centrality similarity: Measuring the diversity of profession levels of interests

    Science.gov (United States)

    Yan, Deng-Cheng; Li, Ming; Wang, Bing-Hong

    2017-08-01

    To understand the relations between developers and software, we study a collaborative coding platform from the perspective of networks, including follower networks, dependence networks and developer-project bipartite networks. Through the analyzing of degree distribution, PageRank and degree-dependent nearest neighbors' centrality, we find that the degree distributions of all networks have a power-law form except the out-degree distributions of dependence networks. The nearest neighbors' centrality is negatively correlated with degree for developers but fluctuates around the average for projects. In order to measure the diversity of profession levels of interests, a new index called dependence centrality similarity is proposed and the correlation between dependence centrality similarity and degree is investigated. The result shows an obvious negative correlations between dependence centrality similarity and degree.

  16. Negative blood oxygen level dependent signals during speech comprehension.

    Science.gov (United States)

    Rodriguez Moreno, Diana; Schiff, Nicholas D; Hirsch, Joy

    2015-05-01

    Speech comprehension studies have generally focused on the isolation and function of regions with positive blood oxygen level dependent (BOLD) signals with respect to a resting baseline. Although regions with negative BOLD signals in comparison to a resting baseline have been reported in language-related tasks, their relationship to regions of positive signals is not fully appreciated. Based on the emerging notion that the negative signals may represent an active function in language tasks, the authors test the hypothesis that negative BOLD signals during receptive language are more associated with comprehension than content-free versions of the same stimuli. Regions associated with comprehension of speech were isolated by comparing responses to passive listening to natural speech to two incomprehensible versions of the same speech: one that was digitally time reversed and one that was muffled by removal of high frequencies. The signal polarity was determined by comparing the BOLD signal during each speech condition to the BOLD signal during a resting baseline. As expected, stimulation-induced positive signals relative to resting baseline were observed in the canonical language areas with varying signal amplitudes for each condition. Negative BOLD responses relative to resting baseline were observed primarily in frontoparietal regions and were specific to the natural speech condition. However, the BOLD signal remained indistinguishable from baseline for the unintelligible speech conditions. Variations in connectivity between brain regions with positive and negative signals were also specifically related to the comprehension of natural speech. These observations of anticorrelated signals related to speech comprehension are consistent with emerging models of cooperative roles represented by BOLD signals of opposite polarity.

  17. Controller Strategies for Automation Tool Use under Varying Levels of Trajectory Prediction Uncertainty

    Science.gov (United States)

    Morey, Susan; Prevot, Thomas; Mercer, Joey; Martin, Lynne; Bienert, Nancy; Cabrall, Christopher; Hunt, Sarah; Homola, Jeffrey; Kraut, Joshua

    2013-01-01

    A human-in-the-loop simulation was conducted to examine the effects of varying levels of trajectory prediction uncertainty on air traffic controller workload and performance, as well as how strategies and the use of decision support tools change in response. This paper focuses on the strategies employed by two controllers from separate teams who worked in parallel but independently under identical conditions (airspace, arrival traffic, tools) with the goal of ensuring schedule conformance and safe separation for a dense arrival flow in en route airspace. Despite differences in strategy and methods, both controllers achieved high levels of schedule conformance and safe separation. Overall, results show that trajectory uncertainties introduced by wind and aircraft performance prediction errors do not affect the controllers' ability to manage traffic. Controller strategies were fairly robust to changes in error, though strategies were affected by the amount of delay to absorb (scheduled time of arrival minus estimated time of arrival). Using the results and observations, this paper proposes an ability to dynamically customize the display of information including delay time based on observed error to better accommodate different strategies and objectives.

  18. Spatially-varying surface roughness and ground-level air quality in an operational dispersion model

    International Nuclear Information System (INIS)

    Barnes, M.J.; Brade, T.K.; MacKenzie, A.R.; Whyatt, J.D.; Carruthers, D.J.; Stocker, J.; Cai, X.; Hewitt, C.N.

    2014-01-01

    Urban form controls the overall aerodynamic roughness of a city, and hence plays a significant role in how air flow interacts with the urban landscape. This paper reports improved model performance resulting from the introduction of variable surface roughness in the operational air-quality model ADMS-Urban (v3.1). We then assess to what extent pollutant concentrations can be reduced solely through local reductions in roughness. The model results suggest that reducing surface roughness in a city centre can increase ground-level pollutant concentrations, both locally in the area of reduced roughness and downwind of that area. The unexpected simulation of increased ground-level pollutant concentrations implies that this type of modelling should be used with caution for urban planning and design studies looking at ventilation of pollution. We expect the results from this study to be relevant for all atmospheric dispersion models with urban-surface parameterisations based on roughness. -- Highlights: • Spatially variable roughness improved performance of an operational model. • Scenario modelling explored effect of reduced roughness on air pollution. • Reducing surface roughness can increase modelled ground-level pollution. • Damped vertical mixing outweighs increased horizontal advection in model study. • Result should hold for any model with a land-surface coupling based on roughness. -- Spatially varying roughness improves model simulations of urban air pollutant dispersion. Reducing roughness does not always decrease ground-level pollution concentrations

  19. Angular momentum dependence of the nuclear level density parameter

    International Nuclear Information System (INIS)

    Aggarwal, Mamta; Kailas, S.

    2010-01-01

    Dependence of nuclear level density parameter on the angular momentum and temperature is investigated in a theoretical framework using the statistical theory of hot rotating nuclei. The structural effects are incorporated by including shell correction, shape, and deformation. The nuclei around Z≅50 with an excitation energy range of 30 to 40 MeV are considered. The calculations are in good agreement with the experimentally deduced inverse level density parameter values especially for 109 In, 113 Sb, 122 Te, 123 I, and 127 Cs nuclei.

  20. Relationships Between Herpetofaunal Community Structure and Varying Levels of Overstory Tree Retention in Northern Alabama: First-year Results

    Science.gov (United States)

    Zachary I. Felix; Yong Wang; Callie Jo Schweitzer

    2004-01-01

    Forest managers are increasingly considering the effects their decisions have on the biodiversity of an area. However, there is often a lack of data upon which to evaluate these decisions. We conducted research to examine the relationship between silvicultural techniques, particularly shelterwood cuts with varying levels of basal area retention, and the community...

  1. A Busy period analysis of the level dependent PH/PH/1/K queue

    NARCIS (Netherlands)

    Al Hanbali, Ahmad

    2011-01-01

    In this paper, we study the transient behavior of a level dependent single server queuing system with a waiting room of finite size during the busy period. The focus is on the level dependent PH/PH/1/K queue. We derive in closed form the joint transform of the length of the busy period, the number

  2. State-dependent differential Riccati equation to track control of time-varying systems with state and control nonlinearities.

    Science.gov (United States)

    Korayem, M H; Nekoo, S R

    2015-07-01

    This work studies an optimal control problem using the state-dependent Riccati equation (SDRE) in differential form to track for time-varying systems with state and control nonlinearities. The trajectory tracking structure provides two nonlinear differential equations: the state-dependent differential Riccati equation (SDDRE) and the feed-forward differential equation. The independence of the governing equations and stability of the controller are proven along the trajectory using the Lyapunov approach. Backward integration (BI) is capable of solving the equations as a numerical solution; however, the forward solution methods require the closed-form solution to fulfill the task. A closed-form solution is introduced for SDDRE, but the feed-forward differential equation has not yet been obtained. Different ways of solving the problem are expressed and analyzed. These include BI, closed-form solution with corrective assumption, approximate solution, and forward integration. Application of the tracking problem is investigated to control robotic manipulators possessing rigid or flexible joints. The intention is to release a general program for automatic implementation of an SDDRE controller for any manipulator that obeys the Denavit-Hartenberg (D-H) principle when only D-H parameters are received as input data. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  3. Adolescent Sexual Behaviors at Varying Levels of Substance Use Frequency

    Science.gov (United States)

    Floyd, Leah J.; Latimer, William

    2010-01-01

    Combining substance use and sex compounds the risk of contracting sexually transmitted diseases, including HIV. However, the association between substance use and sexual behaviors may vary by substance and sexual behavior. The current study sought to examine the relationship between alcohol and marijuana use frequency and specific sexual…

  4. Copper absorption and copper balance during consecutive periods for rats fed varying levels of dietary copper

    International Nuclear Information System (INIS)

    Stuart, M.A.; Johnson, P.E.

    1986-01-01

    Copper (Cu) balance and absorption were studied to determine the extent to which absorption is dependent on dietary Cu. Over 12 consecutive 5-d metabolic periods, Cu balance was determined for four groups of young growing rats (n = 8) fed modified AIN-76 diets having different levels of added Cu (2.5, 5.0, 10 or 20 micrograms/g). Among groups, mean body weights did not differ over time (P greater than 0.05). There were no significant differences among groups for liver, heart or plasma Cu. Rats in all groups were in positive Cu balance throughout the study. After consuming the experimental diets for 10 d, rats eating 10 or 20 micrograms Cu/g diet showed a more positive Cu balance than did rats in the other groups. This trend continued until d 60. For rats eating 20 micrograms Cu/g diet, balance varied significantly over time. Three test meals labeled with stable 65Cu were fed at d 10, 40 and 50, respectively. Apparent Cu absorption, as determined by fecal monitoring of 65Cu, did not change appreciably over time for rats eating 2.5 or 5.0 micrograms Cu/g diet. A test meal labeled with radioactive 67Cu was fed at d 40. For rats eating 2.5 micrograms Cu/g diet, apparent absorption was higher (31%) than that for all other groups (5.0, 23%; 10, 19%; 20, 16%; P less than 0.05). Absorption values determined by whole-body retention of 67Cu were similar to those determined by fecal monitoring of 65Cu

  5. Nicotine Dependence and Urinary Nicotine, Cotinine and Hydroxycotinine Levels in Daily Smokers.

    Science.gov (United States)

    Van Overmeire, Ilse P I; De Smedt, Tom; Dendale, Paul; Nackaerts, Kristiaan; Vanacker, Hilde; Vanoeteren, Jan F A; Van Laethem, Danny M G; Van Loco, Joris; De Cremer, Koen A J

    2016-09-01

    Nicotine dependence and smoking frequency are critical factors for smoking cessation. The aims of this study are (1) to determine if nicotine dependence Fagerström Test for Nicotine Dependence (FTND) scores are associated with urinary levels of nicotine metabolites, (2) to assess the relationship of hydroxycotinine/cotinine ratio with FTND score and cigarettes smoked per day (CPD), and (3) to identify significant predictors of cigarettes per day among biomarker concentrations and individual FTND items. Urine samples and questionnaire data of 239 daily smokers were obtained. Nicotine, cotinine and hydroxycotinine urinary levels were determined by UPLC MS/MS.Multiple linear regression models were developed to explore the relationship between nicotine, cotinine, hydroxycotinine levels and separate FTND scores (for all six items). We found significant correlations between the different urinary biomarker concentrations, and the FTND score. The time before the first cigarette after waking (TTFC) was significantly associated with the nicotine, cotinine and hydroxycotinine concentrations. No association was found between the ratio of hydroxycotinine to cotinine and either the FTND or the CPD. A model including four FTND questions, sex, age, and the cotinine concentration, accounted for 45% of the variance of CPD. There are significant relationships between urinary levels of nicotine, cotinine, and hydroxycotinine and the FTND score. Especially the FTND question about TTFC is relevant for explaining the biomarker concentrations. CPD (below 15) was significantly explained by four FTND dependence items and urinary cotinine levels in a regression model. We investigated associations between urinary levels of nicotine, cotinine, and hydroxycotinine in daily smokers and the FTND scores for nicotine dependence. We did not find association between the hydroxycotinine/cotinine ratio and CPD. We developed a model that explains the cigarettes smoked daily (CPD) in a group of light

  6. Dependency of high coastal water level and river discharge at the global scale

    Science.gov (United States)

    Ward, P.; Couasnon, A.; Haigh, I. D.; Muis, S.; Veldkamp, T.; Winsemius, H.; Wahl, T.

    2017-12-01

    It is widely recognized that floods cause huge socioeconomic impacts. From 1980-2013, global flood losses exceeded $1 trillion, with 220,000 fatalities. These impacts are particularly hard felt in low-lying densely populated deltas and estuaries, whose location at the coast-land interface makes them naturally prone to flooding. When river and coastal floods coincide, their impacts in these deltas and estuaries are often worse than when they occur in isolation. Such floods are examples of so-called `compound events'. In this contribution, we present the first global scale analysis of the statistical dependency of high coastal water levels (and the storm surge component alone) and river discharge. We show that there is statistical dependency between these components at more than half of the stations examined. We also show time-lags in the highest correlation between peak discharges and coastal water levels. Finally, we assess the probability of the simultaneous occurrence of design discharge and design coastal water levels, assuming both independence and statistical dependence. For those stations where we identified statistical dependency, the probability is between 1 and 5 times greater, when the dependence structure is accounted for. This information is essential for understanding the likelihood of compound flood events occurring at locations around the world as well as for accurate flood risk assessments and effective flood risk management. The research was carried out by analysing the statistical dependency between observed coastal water levels (and the storm surge component) from GESLA-2 and river discharge using gauged data from GRDC stations all around the world. The dependence structure was examined using copula functions.

  7. Estimating varying coefficients for partial differential equation models.

    Science.gov (United States)

    Zhang, Xinyu; Cao, Jiguo; Carroll, Raymond J

    2017-09-01

    Partial differential equations (PDEs) are used to model complex dynamical systems in multiple dimensions, and their parameters often have important scientific interpretations. In some applications, PDE parameters are not constant but can change depending on the values of covariates, a feature that we call varying coefficients. We propose a parameter cascading method to estimate varying coefficients in PDE models from noisy data. Our estimates of the varying coefficients are shown to be consistent and asymptotically normally distributed. The performance of our method is evaluated by a simulation study and by an empirical study estimating three varying coefficients in a PDE model arising from LIDAR data. © 2017, The International Biometric Society.

  8. The Moderating Effect of Psychological Characteristics upon the Visionary Leadership Behavior of Principals from Varying Levels of School Climate.

    Science.gov (United States)

    Kenworthy, Sue

    1994-01-01

    Results from a study with 41 Hawaiian elementary school principals indicate that, although there is no significant difference in visionary leadership scores of principals from varying levels of school climate when covaried with psychological characteristics, there is a significant main effect for "capacity of status" on visionary…

  9. Blood cadmium levels in women of childbearing age vary by race/ethnicity

    Energy Technology Data Exchange (ETDEWEB)

    Mijal, Renee S., E-mail: rmijal@epi.msu.edu; Holzman, Claudia B. [Department of Epidemiology, Michigan State University, B601 W. Fee Hall, East Lansing, MI 48824 (United States)

    2010-07-15

    The heavy metal cadmium (Cd) is long-lived in the body and low-level cumulative exposure, even among non-smokers, has been associated with changes in renal function and bone metabolism. Women are more susceptible to the adverse effects of Cd and have higher body burdens. Due to increased dietary absorption of Cd in menstruating women and the long half-life of the metal, reproductive age exposures are likely important contributors to overall body burden and disease risk. We examined blood Cd levels in women of reproductive age in the US and assessed variation by race/ethnicity. Blood Cd concentrations were compared among female NHANES participants aged 20-44, who were neither pregnant nor breastfeeding. Sample size varied primarily based on inclusion/exclusion of smokers (n=1734-3121). Mean Cd concentrations, distributions and odds ratios were calculated using SUDAAN. For logistic regression Cd was modeled as high (the upper 10% of the distribution) vs. the remainder. Overall, Mexican Americans had lower Cd levels than other groups due to a lower smoking prevalence, smoking being an important source of exposure. Among never-smokers, Mexican Americans had 1.77 (95% CI: 1.06-2.96) times the odds of high Cd as compared to non-Hispanic Whites after controlling for age and low iron (ferritin). For non-Hispanic Blacks, the odds were 2.96 (CI: 1.96-4.47) times those of non-Hispanic Whites in adjusted models. Adjustment for relevant reproductive factors or exposure to environmental tobacco smoke had no effect. In this nationally representative sample, non-smoking Mexican American and non-Hispanic Black women were more likely to have high Cd than non-Hispanic White women. Additional research is required to determine the underlying causes of these differences.

  10. Blood cadmium levels in women of childbearing age vary by race/ethnicity

    International Nuclear Information System (INIS)

    Mijal, Renee S.; Holzman, Claudia B.

    2010-01-01

    The heavy metal cadmium (Cd) is long-lived in the body and low-level cumulative exposure, even among non-smokers, has been associated with changes in renal function and bone metabolism. Women are more susceptible to the adverse effects of Cd and have higher body burdens. Due to increased dietary absorption of Cd in menstruating women and the long half-life of the metal, reproductive age exposures are likely important contributors to overall body burden and disease risk. We examined blood Cd levels in women of reproductive age in the US and assessed variation by race/ethnicity. Blood Cd concentrations were compared among female NHANES participants aged 20-44, who were neither pregnant nor breastfeeding. Sample size varied primarily based on inclusion/exclusion of smokers (n=1734-3121). Mean Cd concentrations, distributions and odds ratios were calculated using SUDAAN. For logistic regression Cd was modeled as high (the upper 10% of the distribution) vs. the remainder. Overall, Mexican Americans had lower Cd levels than other groups due to a lower smoking prevalence, smoking being an important source of exposure. Among never-smokers, Mexican Americans had 1.77 (95% CI: 1.06-2.96) times the odds of high Cd as compared to non-Hispanic Whites after controlling for age and low iron (ferritin). For non-Hispanic Blacks, the odds were 2.96 (CI: 1.96-4.47) times those of non-Hispanic Whites in adjusted models. Adjustment for relevant reproductive factors or exposure to environmental tobacco smoke had no effect. In this nationally representative sample, non-smoking Mexican American and non-Hispanic Black women were more likely to have high Cd than non-Hispanic White women. Additional research is required to determine the underlying causes of these differences.

  11. Does Remediation Work for All Students? How the Effects of Postsecondary Remedial and Developmental Courses Vary by Level of Academic Preparation

    Science.gov (United States)

    Boatman, Angela; Long, Bridget Terry

    2018-01-01

    We examine the impact of remedial and developmental courses on college students with varying levels of academic preparedness, thus focusing on a wider range of students than previous studies. Using a regression discontinuity design, we provide causal estimates of the effects of placement in different levels of remedial courses on short-,…

  12. Dependence levels in users of electronic cigarettes, nicotine gums and tobacco cigarettes.

    Science.gov (United States)

    Etter, Jean-François; Eissenberg, Thomas

    2015-02-01

    To assess dependence levels in users of e-cigarettes, and compare them with dependence levels in users of nicotine gums and tobacco cigarettes. Self-reports from cross-sectional Internet and mail surveys. Comparisons of: (a) 766 daily users of nicotine-containing e-cigarettes with 30 daily users of nicotine-free e-cigarettes; (b) 911 former smokers who used the e-cigarette daily with 451 former smokers who used the nicotine gum daily (but no e-cigarette); (c) 125 daily e-cigarette users who smoked daily (dual users) with two samples of daily smokers who did not use e-cigarettes (2206 enrolled on the Internet and 292 enrolled by mail from the general population of Geneva). We used the Fagerström test for nicotine dependence, the nicotine dependence syndrome scale, the cigarette dependence scale and versions of these scales adapted for e-cigarettes and nicotine gums. Dependence ratings were slightly higher in users of nicotine-containing e-cigarettes than in users of nicotine-free e-cigarettes. In former smokers, long-term (>3 months) users of e-cigarettes were less dependent on e-cigarettes than long-term users of the nicotine gum were dependent on the gum. There were few differences in dependence ratings between short-term (≤3 months) users of gums or e-cigarettes. Dependence on e-cigarettes was generally lower in dual users than dependence on tobacco cigarettes in the two other samples of daily smokers. Some e-cigarette users were dependent on nicotine-containing e-cigarettes, but these products were less addictive than tobacco cigarettes. E-cigarettes may be as or less addictive than nicotine gums, which themselves are not very addictive. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Temperature dependent energy levels of methylammonium lead iodide perovskite

    Science.gov (United States)

    Foley, Benjamin J.; Marlowe, Daniel L.; Sun, Keye; Saidi, Wissam A.; Scudiero, Louis; Gupta, Mool C.; Choi, Joshua J.

    2015-06-01

    Temperature dependent energy levels of methylammonium lead iodide are investigated using a combination of ultraviolet photoemission spectroscopy and optical spectroscopy. Our results show that the valence band maximum and conduction band minimum shift down in energy by 110 meV and 77 meV as temperature increases from 28 °C to 85 °C. Density functional theory calculations using slab structures show that the decreased orbital splitting due to thermal expansion is a major contribution to the experimentally observed shift in energy levels. Our results have implications for solar cell performance under operating conditions with continued sunlight exposure and increased temperature.

  14. Nicotine Dependence and Urinary Nicotine, Cotinine and Hydroxycotinine Levels in Daily Smokers

    OpenAIRE

    Van Overmeire, Ilse P. I.; De Smedt, Tom; Dendale, Paul; Nackaerts, Kristiaan; Vanacker, Hilde; Vanoeteren, Jan F. A.; Van Laethem, Danny M. G.; Van Loco, Joris; De Cremer, Koen A. J.

    2016-01-01

    Nicotine dependence and smoking frequency are critical factors for smoking cessation. The aims of this study are (1) to determine if nicotine dependence Fagerstrom Test for Nicotine Dependence (FTND) scores are associated with urinary levels of nicotine metabolites, (2) to assess the relationship of hydroxycotinine/cotinine ratio with FTND score and cigarettes smoked per day (CPD), and (3) to identify significant predictors of cigarettes per day among biomarker concentrations and individual F...

  15. Simultaneous reflection masking: dependency on direct sound level and hearing-impairment

    DEFF Research Database (Denmark)

    Buchholz, Jörg; Mihai, Paul Glad

    2008-01-01

    B-SL direct sound level, NH-listeners showed a binaural suppression effect for delays smaller than 7-10 ms and a binaural enhancement effect for larger delays. When decreasing the direct sound level to 15 dB-SL, the only significant change observed was that the dichotic RMT increased for delays larger than...... expected from changed auditory filter bandwidth and audi-bility. However, the stimulus level-dependency of the auditory filters’ bandwidth was not reflected in the SRMT data....

  16. Anaerobic Nitrogen Turnover by Sinking Diatom Aggregates at Varying Ambient Oxygen Levels

    Directory of Open Access Journals (Sweden)

    Peter eStief

    2016-02-01

    Full Text Available In the world’s oceans, even relatively low oxygen (O2 levels inhibit anaerobic nitrogen cycling by free-living microbes. Sinking organic aggregates, however, might provide oxygen-depleted microbial hotspots in otherwise oxygenated surface waters. Here we show that sinking diatom aggregates can host anaerobic nitrogen cycling at ambient O2 levels well above the hypoxic threshold. Aggregates were produced from the ubiquitous diatom Skeletonema marinoi and the natural microbial community of seawater. Microsensor profiling through the center of sinking aggregates revealed internal anoxia at ambient 40% air saturation (~100 µmol O2 L-1 and below. Accordingly, anaerobic nitrate turnover inside the aggregates was evident within this range of ambient O2 levels. In incubations with 15N-labeled nitrate, individual Skeletonema aggregates produced NO2- (up to 10.7 nmol N h-1 per aggregate, N2 (up to 7.1 nmol N h-1, NH4+ (up to 2.0 nmol N h-1, and N2O (up to 0.2 nmol N h-1. Intriguingly, nitrate stored inside the diatom cells served as an additional, internal nitrate source for N2 production, which may partially uncouple anaerobic nitrate turnover by diatom aggregates from direct ambient nitrate supply. Sinking diatom aggregates can contribute directly to fixed-nitrogen loss in low-oxygen environments in the ocean and vastly expand the ocean volume in which anaerobic nitrogen turnover is possible, despite relatively high ambient O2 levels. Depending on the extent of intracellular nitrate consumption during the sinking process, diatom aggregates may also be involved in the long-distance export of nitrate to the deep ocean.

  17. Preliminary test of cigarette nicotine discrimination threshold in non-dependent versus dependent smokers.

    Science.gov (United States)

    Perkins, Kenneth A; Kunkle, Nicole; Karelitz, Joshua L; Perkins, K A; Kunkle, N; Karelitz, J L

    2017-06-01

    Despite its potential for understanding tobacco dependence, behavioral discrimination of nicotine via smoking has not been formally examined as a function of nicotine dependence level. Spectrum research cigarettes were used to compare non-dependent with dependent smokers on the lowest content of nicotine they could discriminate (i.e., "threshold"). Dependent (n=21; 16M, 5F) or non-dependent (n=7; 4M, 3F) smokers were tested on ability to discriminate between cigarettes with nicotine contents of 17, 11, 5, 2, and 1mg/g, one per session, from an "ultra-low" cigarette with 0.4mg/g (all had 9-10mg "tar"). All abstained from smoking overnight prior to sessions, and number of sessions was determined by the lowest nicotine content they could reliably discriminate from the ultra-low on >80% of trials (i.e., ≥5 of 6). Subjective perceptions and cigarette choice behavior were also assessed and related to discrimination behavior. Discrimination thresholds (and most perceptions) did not differ between dependent and non-dependent smokers, with median thresholds of 11mg/g for both subgroups. Yet, "liking" and puff choice for threshold cigarettes were greater in dependent but not non-dependent smokers, while cigarettes with nicotine contents below threshold did not support "liking" or choice in both groups. In sum, this preliminary study suggests threshold for discriminating nicotine via smoking may not vary by dependence level, and further study is needed to confirm that cigarettes unable to be discriminated are also not reinforcing. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Hydrogen and methane generation from large hydraulic plant: Thermo-economic multi-level time-dependent optimization

    International Nuclear Information System (INIS)

    Rivarolo, M.; Magistri, L.; Massardo, A.F.

    2014-01-01

    Highlights: • We investigate H 2 and CH 4 production from very large hydraulic plant (14 GW). • We employ only “spilled energy”, not used by hydraulic plant, for H 2 production. • We consider the integration with energy taken from the grid at different prices. • We consider hydrogen conversion in chemical reactors to produce methane. • We find plants optimal size using a time-dependent thermo-economic approach. - Abstract: This paper investigates hydrogen and methane generation from large hydraulic plant, using an original multilevel thermo-economic optimization approach developed by the authors. Hydrogen is produced by water electrolysis employing time-dependent hydraulic energy related to the water which is not normally used by the plant, known as “spilled water electricity”. Both the demand for spilled energy and the electrical grid load vary widely by time of year, therefore a time-dependent hour-by-hour one complete year analysis has been carried out, in order to define the optimal plant size. This time period analysis is necessary to take into account spilled energy and electrical load profiles variability during the year. The hydrogen generation plant is based on 1 MWe water electrolysers fuelled with the “spilled water electricity”, when available; in the remaining periods, in order to assure a regular H 2 production, the energy is taken from the electrical grid, at higher cost. To perform the production plant size optimization, two hierarchical levels have been considered over a one year time period, in order to minimize capital and variable costs. After the optimization of the hydrogen production plant size, a further analysis is carried out, with a view to converting the produced H 2 into methane in a chemical reactor, starting from H 2 and CO 2 which is obtained with CCS plants and/or carried by ships. For this plant, the optimal electrolysers and chemical reactors system size is defined. For both of the two solutions, thermo

  19. Growth Performance and Carcass Characteristics of Korean Native Ducks Fed Diets with Varying Levels of Limiting Amino Acids

    Directory of Open Access Journals (Sweden)

    Y. K. Choo

    2014-04-01

    Full Text Available There are multiple experiments conducted with male Korean native ducks (KND to evaluate the optimal levels of limiting amino acids (AA. In Exp. 1, a total of 450 one-d-old male KNDs were divided into five groups with six replicates and fed experimental diets with varying levels of lysine, total sulfur amino acids (TSAA and threonine (T1, 0.90/0.74/0.70%; T2, 1.00/0.82/0.77%; T3, 1.10/0.90/0.85%; T4, 1.20/0.98/0.93%; T5, 1.30/1.07/1.01% to 21 d of age. In Exp. 2, one-d-old male KND were received and fed commercial starter diet from hatching to 21 d of age, and then divided into five groups with six replicates and fed one of five diets varying levels of lysine, TSAA, and threonine (T1, 0.73/0.62/0.54%; T2, 0.80/0.68/0.60%; T3, 0.87/0.74/0.65%; T4, 0.94/0.80/0.70%; T5, 1.01/0.86/0.75% during 22 to 56 d of age, respectively. The BW gain was linearly increased as dietary limiting AA levels increased to 1.20% lysine, 0.98% TSAA and 0.93% threonine. There were no significant differences in feed intake, gain:feed and uniformity among groups. In Exp. 2, the BW gain and gain:feed were not affected by dietary limiting AA levels. There were no significant differences in carcass characteristics and meat quality among groups. The growth performance and carcass characteristics did not show the significant response to increasing dietary limiting AA levels in KND during 22 to 56 d of age. In conclusion, the levels of lysine, TSAA and threonine necessary to maximize growth for starter phase were at least 1.20%, 0.98%, and 0.93%, respectively. On the other hands, KND require relatively low levels of limiting AA for late growth and carcass yield. The dietary levels of 0.73% lysine, 0.62% TSAA and 0.54% threonine appear to be adequate during growing phase.

  20. Temperature dependent energy levels of methylammonium lead iodide perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Foley, Benjamin J.; Marlowe, Daniel L.; Choi, Joshua J., E-mail: jjc6z@virginia.edu, E-mail: mgupta@virginia.edu, E-mail: scudiero@wsu.edu [Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Sun, Keye; Gupta, Mool C., E-mail: jjc6z@virginia.edu, E-mail: mgupta@virginia.edu, E-mail: scudiero@wsu.edu [Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Saidi, Wissam A. [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States); Scudiero, Louis, E-mail: jjc6z@virginia.edu, E-mail: mgupta@virginia.edu, E-mail: scudiero@wsu.edu [Chemistry Department and Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164 (United States)

    2015-06-15

    Temperature dependent energy levels of methylammonium lead iodide are investigated using a combination of ultraviolet photoemission spectroscopy and optical spectroscopy. Our results show that the valence band maximum and conduction band minimum shift down in energy by 110 meV and 77 meV as temperature increases from 28 °C to 85 °C. Density functional theory calculations using slab structures show that the decreased orbital splitting due to thermal expansion is a major contribution to the experimentally observed shift in energy levels. Our results have implications for solar cell performance under operating conditions with continued sunlight exposure and increased temperature.

  1. Nuclear level density parameter 's dependence on angular momentum

    International Nuclear Information System (INIS)

    Aggarwal, Mamta; Kailas, S.

    2009-01-01

    Nuclear level densities represent a very important ingredient in the statistical Model calculations of nuclear reaction cross sections and help to understand the microscopic features of the excited nuclei. Most of the earlier experimental nuclear level density measurements are confined to low excitation energy and low spin region. A recent experimental investigation of nuclear level densities in high excitation energy and angular momentum domain with some interesting results on inverse level density parameter's dependence on angular momentum in the region around Z=50 has motivated us to study and analyse these experimental results in a microscopic theoretical framework. In the experiment, heavy ion fusion reactions are used to populate the excited and rotating nuclei and measured the α particle evaporation spectra in coincidence with ray multiplicity. Residual nuclei are in the range of Z R 48-55 with excitation energy range 30 to 40 MeV and angular momentum in 10 to 25. The inverse level density parameter K is found to be in the range of 9.0 - 10.5 with some exceptions

  2. A mechanistic analysis of density dependence in algal population dynamics

    Directory of Open Access Journals (Sweden)

    Adrian eBorlestean

    2015-04-01

    Full Text Available Population density regulation is a fundamental principle in ecology, but the specific process underlying functional expression of density dependence remains to be fully elucidated. One view contends that patterns of density dependence are largely fixed across a species irrespective of environmental conditions, whereas another is that the strength and expression of density dependence are fundamentally variable depending on the nature of exogenous or endogenous constraints acting on the population. We conducted a study investigating the expression of density dependence in Chlamydomonas spp. grown under a gradient from low to high nutrient density. We predicted that the relationship between per capita growth rate (pgr and population density would vary from concave up to concave down as nutrient density became less limiting and populations experienced weaker density regulation. Contrary to prediction, we found that the relationship between pgr and density became increasingly concave-up as nutrient levels increased. We also found that variation in pgr increased, and pgr levels reached higher maxima in nutrient-limited environments. Most likely, these results are attributable to population growth suppression in environments with high intraspecific competition due to limited nutrient resources. Our results suggest that density regulation is strongly variable depending on exogenous and endogenous processes acting on the population, implying that expression of density dependence depends extensively on local conditions. Additional experimental work should reveal the mechanisms influencing how the expression of density dependence varies across populations through space and time.

  3. Sulfonylurea therapy improves glucose disposal without changing skeletal muscle GLUT4 levels in noninsulin-dependent diabetes mellitus subjects

    DEFF Research Database (Denmark)

    Vestergaard, H; Weinreb, J E; Rosen, A S

    1995-01-01

    alteration in GLUT4 levels expressed either per microgram membrane protein or per DNA. In summary, the improvement in glycemic control and glucose disposal in NIDDM subjects receiving gliclazide therapy cannot be explained by increased expression of GLUT4 in muscle. Thus, therapeutic effects on insulin......A major pathological feature of noninsulin-dependent diabetes (NIDDM) is defective insulin-stimulated glucose transport in skeletal muscle. When NIDDM subjects are assessed as a group, GLUT4 gene expression in skeletal muscle varies widely and is not different from that in controls. Thus......, longitudinal studies are needed to assess whether changes in GLUT4 expression in muscle of NIDDM subjects could be responsible for changes in glucose disposal. The question is timely because recent studies in transgenic mice show that increasing GLUT4 expression can increase insulin-stimulated glucose uptake...

  4. On the time-dependent behavior of a cylindrical salt dome with a high-level waste repository

    International Nuclear Information System (INIS)

    Prij, J.

    1988-01-01

    In a salt dome with a repository for high-level radioactive and heat-generating waste, thermal stresses develop. These stresses can influence the isolation capability of the salt dome if these stresses can initiate cracks or introduce movements along existing closed flaws. The influence of the thermomechanical properties of the rock salt and the surrounding rocks on the thermal stresses and the surface rise is discussed. This discussion is based on a number of finite element creep analyses of a homogeneous cylindrical salt dome. The parameters, varied in the analyses, are constants in the thermomechanical constitutive behavior of salt and rocks, and furthermore the thermal loading has been varied. It is shown that variations in the creep properties, which result in differences in creep strain rate of a factor of 100, have only a very limited influence on the thermal stresses and the surface rise. Of more importance is the elastic stiffness of the materials. In all creep analyses the thermal stresses in the salt are compressive and the shear stresses remain below 2 MPa. The results are evaluated using an analytical treatment. Based on this evaluation, it is shown that the observed trends in the numerical results have a more general character and are not strictly limited to the geometry chosen. It is concluded that the thermal stresses in the salt formation are not strongly dependent on the creep properties of the rock salt

  5. Delay-dependent exponential stability of cellular neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Zhang Qiang; Wei Xiaopeng; Xu Jin

    2005-01-01

    The global exponential stability of cellular neural networks (CNNs) with time-varying delays is analyzed. Two new sufficient conditions ensuring global exponential stability for delayed CNNs are obtained. The conditions presented here are related to the size of delay. The stability results improve the earlier publications. Two examples are given to demonstrate the effectiveness of the obtained results

  6. Decreased serum level of NGF in alcohol-dependent patients with declined executive function

    Directory of Open Access Journals (Sweden)

    Bae H

    2014-11-01

    Full Text Available Hwallip Bae,1 Youngsun Ra,1 Changwoo Han,2 Dai-Jin Kim3 1Department of Psychiatry, Myongji Hospital, Goyang, 2Department of Psychiatry, Keyo Hospital, Uiwang, 3Department of Psychiatry, Seoul St Mary’s Hospital, College of Medicine, Catholic University of Korea, Seoul, South Korea Abstract: The role of neurotrophic factors has been highlighted as a cause of decline in the cognitive function of alcohol-dependent patients. It is known that nerve-growth factor (NGF, one of the neurotrophins, is related to the growth and differentiation of nerve cells, as well as to a decline in cognitive function. The purpose of this study was to investigate the relationship between decreased NGF levels and cognitive decline in alcohol-dependent patients. The serum concentration of NGF was measured in 38 patients with chronic alcohol dependence, and several neuropsychological tests were also performed for cognitive function assessment. The results indicated a significant correlation between serum NGF level and the trail-making test part B, which evaluates executive function, but did not show a significant correlation with other cognitive function tests. An increased serum level of NGF was associated with a decreased completion time in the trail-making test B, and this finding indicates that a high serum level of NGF is related to greater executive function. This finding may imply a protective role of NGF in preventing neuron damage among patients with alcohol dependence. Larger controlled studies will be necessary in the future to investigate this issue further. Keywords: nerve-growth factor, alcohol dependence, executive function, trail-making test

  7. Central recirculation zone analysis in an unconfined tangential swirl burner with varying degrees of premixing

    Energy Technology Data Exchange (ETDEWEB)

    Valera-Medina, A. [CIATEQ, Parque Industrial Bernardo Quintana, Turbomachinery Department, Queretaro (Mexico); Syred, N.; Kay, P.; Griffiths, A. [Cardiff University, School of Engineering, Cardiff, Wales (United Kingdom)

    2011-06-15

    Swirl-stabilised combustion is one of the most widely used techniques for flame stabilisation, uses ranging from gas turbine combustors to pulverised coal-fired power stations. In gas turbines, lean premixed systems are of especial importance, giving the ability to produce low NOx systems coupled with wide stability limits. The common element is the swirl burner, which depends on the generation of an aerodynamically formed central recirculation zone (CRZ) and which serves to recycle heat and active chemical species to the root of the flame as well as providing low-velocity regions where the flame speed can match the local flow velocity. Enhanced mixing in and around the CRZ is another beneficial feature. The structure of the CRZ and hence that of the associated flames, stabilisation and mixing processes have shown to be extremely complex, three-dimensional and time dependent. The characteristics of the CRZ depend very strongly on the level of swirl (swirl number), burner configuration, type of flow expansion, Reynolds number (i.e. flowrate) and equivalence ratio. Although numerical methods have had some success when compared to experimental results, the models still have difficulties at medium to high swirl levels, with complex geometries and varied equivalence ratios. This study thus focuses on experimental results obtained to characterise the CRZ formed under varied combustion conditions with different geometries and some variation of swirl number in a generic swirl burner. CRZ behaviour has similarities to the equivalent isothermal state, but is strongly dependent on equivalence ratio, with interesting effects occurring with a high-velocity fuel injector. Partial premixing and combustion cause more substantive changes to the CRZ than pure diffusive combustion. (orig.)

  8. Generalized Cauchy model of sea level fluctuations with long-range dependence

    Science.gov (United States)

    Li, Ming; Li, Jia-Yue

    2017-10-01

    This article suggests the contributions with two highlights. One is to propose a novel model of sea level fluctuations (sea level for short), which is called the generalized Cauchy (GC) process. It provides a new outlook for the description of local and global behaviors of sea level from a view of fractal in that the fractal dimension D that measures the local behavior of sea level and the Hurst parameter H which characterizes the global behavior of sea level are independent of each other. The other is to show that sea level appears multi-fractal in both spatial and time. Such a meaning of multi-fractal is new in the sense that a pair of fractal parameters (D, H) of sea level is varying with measurement sites and time. This research exhibits that the ranges of D and H of sea level, in general, are 1 ≤ D sea level, we shall show that H > 0 . 96 for all data records at all measurement sites, implying that strong LRD may be a general phenomenon of sea level. On the other side, regarding with the local behavior, we will reveal that there appears D = 1 or D ≈ 1 for data records at a few stations and at some time, but D > 0 . 96 at most stations and at most time, meaning that sea level may appear highly local irregularity more frequently than weak local one.

  9. Effect of varying carbohydrate levels on the uptake and translocation of 32P in Eragrostis curvula (Schrad.) Nees

    International Nuclear Information System (INIS)

    Naidoo, G.; Steinke, T.D.

    1979-01-01

    The uptake and subsequent translocation of 32 P among root, crown and leaf tissues of Eragrostis curvula were investigated in plants with varying carbohydrate levels. Plants were depleted of carbohydrates by being subjected to 3 days of continuous darkness and by defoliation. Plant roots were introduced to nutrient solutions containing 32 P, at 0, 3, 6, 9, 12, 15 and 21 days after the depletion treatments. Initially, plants depleted of carbohydrates absorbed and translocated less 32 P than the controls. Subsequently, uptake and translocation increased probably to restore the pools of phosphate to levels prior to the depletion treatments. Increased 32 P uptake and translocation were related to an adequate supply of reserve carbohydrates [af

  10. New varying speed of light theories

    CERN Document Server

    Magueijo, J

    2003-01-01

    We review recent work on the possibility of a varying speed of light (VSL). We start by discussing the physical meaning of a varying $c$, dispelling the myth that the constancy of $c$ is a matter of logical consistency. We then summarize the main VSL mechanisms proposed so far: hard breaking of Lorentz invariance; bimetric theories (where the speeds of gravity and light are not the same); locally Lorentz invariant VSL theories; theories exhibiting a color dependent speed of light; varying $c$ induced by extra dimensions (e.g. in the brane-world scenario); and field theories where VSL results from vacuum polarization or CPT violation. We show how VSL scenarios may solve the cosmological problems usually tackled by inflation, and also how they may produce a scale-invariant spectrum of Gaussian fluctuations, capable of explaining the WMAP data. We then review the connection between VSL and theories of quantum gravity, showing how ``doubly special'' relativity has emerged as a VSL effective model of quantum space...

  11. CVTresh: R Package for Level-Dependent Cross-Validation Thresholding

    Directory of Open Access Journals (Sweden)

    Donghoh Kim

    2006-04-01

    Full Text Available The core of the wavelet approach to nonparametric regression is thresholding of wavelet coefficients. This paper reviews a cross-validation method for the selection of the thresholding value in wavelet shrinkage of Oh, Kim, and Lee (2006, and introduces the R package CVThresh implementing details of the calculations for the procedures. This procedure is implemented by coupling a conventional cross-validation with a fast imputation method, so that it overcomes a limitation of data length, a power of 2. It can be easily applied to the classical leave-one-out cross-validation and K-fold cross-validation. Since the procedure is computationally fast, a level-dependent cross-validation can be developed for wavelet shrinkage of data with various sparseness according to levels.

  12. CVTresh: R Package for Level-Dependent Cross-Validation Thresholding

    Directory of Open Access Journals (Sweden)

    Donghoh Kim

    2006-04-01

    Full Text Available The core of the wavelet approach to nonparametric regression is thresholding of wavelet coefficients. This paper reviews a cross-validation method for the selection of the thresholding value in wavelet shrinkage of Oh, Kim, and Lee (2006, and introduces the R package CVThresh implementing details of the calculations for the procedures.This procedure is implemented by coupling a conventional cross-validation with a fast imputation method, so that it overcomes a limitation of data length, a power of 2. It can be easily applied to the classical leave-one-out cross-validation and K-fold cross-validation. Since the procedure is computationally fast, a level-dependent cross-validation can be developed for wavelet shrinkage of data with various sparseness according to levels.

  13. Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Tanabe, Tatsuhiko; Nakajima, Hajime

    1994-01-01

    A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000 C in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000 to 900 C. The trend observed in the tests from 900 to 1000 C can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900 C plays the role of the protective barrier against the boron dissipation into the environment. (orig.)

  14. Degree of multicollinearity and variables involved in linear dependence in additive-dominant models Grau de multicolinearidade e variáveis envolvidas na dependência linear em modelos aditivo-dominantes

    Directory of Open Access Journals (Sweden)

    Juliana Petrini

    2012-12-01

    Full Text Available The objective of this work was to assess the degree of multicollinearity and to identify the variables involved in linear dependence relations in additive-dominant models. Data of birth weight (n=141,567, yearling weight (n=58,124, and scrotal circumference (n=20,371 of Montana Tropical composite cattle were used. Diagnosis of multicollinearity was based on the variance inflation factor (VIF and on the evaluation of the condition indexes and eigenvalues from the correlation matrix among explanatory variables. The first model studied (RM included the fixed effect of dam age class at calving and the covariates associated to the direct and maternal additive and non-additive effects. The second model (R included all the effects of the RM model except the maternal additive effects. Multicollinearity was detected in both models for all traits considered, with VIF values of 1.03 - 70.20 for RM and 1.03 - 60.70 for R. Collinearity increased with the increase of variables in the model and the decrease in the number of observations, and it was classified as weak, with condition index values between 10.00 and 26.77. In general, the variables associated with additive and non-additive effects were involved in multicollinearity, partially due to the natural connection between these covariables as fractions of the biological types in breed composition.O objetivo deste trabalho foi avaliar o grau de multicolinearidade e identificar as variáveis envolvidas na dependência linear em modelos aditivo-dominantes. Foram utilizados dados de peso ao nascimento (n=141.567, peso ao ano (n=58.124 e perímetro escrotal (n=20.371 de bovinos de corte compostos Montana Tropical. O diagnóstico de multicolinearidade foi baseado no fator de inflação de variância (VIF e no exame dos índices de condição e dos autovalores da matriz de correlações entre as variáveis explanatórias. O primeiro modelo estudado (RM incluiu o efeito fixo de classe de idade da mãe ao parto e

  15. PCA-based detection of damage in time-varying systems

    Science.gov (United States)

    Bellino, A.; Fasana, A.; Garibaldi, L.; Marchesiello, S.

    2010-10-01

    When performing Structural Health Monitoring, it is well known that the natural frequencies do not depend only on the damage but also on environmental conditions, such as temperature and humidity. The Principal Component Analysis is used to take this problem into account, because it allows eliminating the effect of external factors. The purpose of the present work is to show that this technique can be successfully used not only for time-invariant systems, but also for time-varying ones. Referring to the latter, one of the most studied systems which shows these characteristics is the bridge with crossing loads, such as the case of the railway bridge studied in present paper; in this case, the mass and the velocity of the train can be considered as "environmental" factors.This paper, after a brief description of the PCA method and one example of its application on time-invariant systems, presents the great potentialities of the methodology when applied to time-varying systems. The results show that this method is able to better detect the presence of damage and also to properly distinguish among different levels of crack depths.

  16. Fermi level dependent native defect formation: Consequences for metal-semiconductor and semiconductor-semiconductor interfaces

    International Nuclear Information System (INIS)

    Walukiewicz, W.

    1988-02-01

    The amphoteric native defect model of the Schottky barrier formation is used to analyze the Fermi level pinning at metal/semiconductor interfaces for submonolayer metal coverages. It is assumed that the energy required for defect generation is released in the process of surface back-relaxation. Model calculations for metal/GaAs interfaces show a weak dependence of the Fermi level pinning on the thickness of metal deposited at room temperature. This weak dependence indicates a strong dependence of the defect formation energy on the Fermi level, a unique feature of amphoteric native defects. This result is in very good agreement with experimental data. It is shown that a very distinct asymmetry in the Fermi level pinning on p- and n-type GaAs observed at liquid nitrogen temperatures can be understood in terms of much different recombination rates for amphoteric native defects in those two types of materials. Also, it is demonstrated that the Fermi level stabilization energy, a central concept of the amphoteric defect system, plays a fundamental role in other phenomena in semiconductors such as semiconductor/semiconductor heterointerface intermixing and saturation of free carrier concentration. 33 refs., 6 figs

  17. Steps Counts among Middle School Students Vary with Aerobic Fitness Level

    Science.gov (United States)

    Le Masurier, Guy C.; Corbin, Charles B.

    2006-01-01

    The purpose of this study was to examine if steps/day taken by middle school students varied based on aerobic fitness classification. Middle school students (N = 223; 112 girls, 111 boys) were assigned to three aerobic fitness categories (HIGH, MOD, LOW) based on results of the FITNESSGRAM PACER test. Four weekdays of pedometer monitoring…

  18. Interrater reliability of quantitative ultrasound using force feedback among examiners with varied levels of experience

    Directory of Open Access Journals (Sweden)

    Michael O. Harris-Love

    2016-06-01

    Full Text Available Background. Quantitative ultrasound measures are influenced by multiple external factors including examiner scanning force. Force feedback may foster the acquisition of reliable morphometry measures under a variety of scanning conditions. The purpose of this study was to determine the reliability of force-feedback image acquisition and morphometry over a range of examiner-generated forces using a muscle tissue-mimicking ultrasound phantom. Methods. Sixty material thickness measures were acquired from a muscle tissue mimicking phantom using B-mode ultrasound scanning by six examiners with varied experience levels (i.e., experienced, intermediate, and novice. Estimates of interrater reliability and measurement error with force feedback scanning were determined for the examiners. In addition, criterion-based reliability was determined using material deformation values across a range of examiner scanning forces (1–10 Newtons via automated and manually acquired image capture methods using force feedback. Results. All examiners demonstrated acceptable interrater reliability (intraclass correlation coefficient, ICC = .98, p .90, p < .001, independent of their level of experience. The measurement error among all examiners was 1.5%–2.9% across all applied stress conditions. Conclusion. Manual image capture with force feedback may aid the reliability of morphometry measures across a range of examiner scanning forces, and allow for consistent performance among examiners with differing levels of experience.

  19. Biochemical and physiological changes in Egyptian Nile fish subjected to varying levels of gamma irradiation

    International Nuclear Information System (INIS)

    Roushdy, H.M.; El-Kashef, H.S.; Imam, A.E.

    1975-01-01

    Radiation is nowadays to be considered as a new parameter in the ecology of water masses. Aquatic organisms, perhaps more than any other group of organisms, are directly exposed to radiation hazard and may be subjected to continuous low-level exposure from bottom material and from internal sources accumulated within their own bodies, originating partly from radionuclides released from nuclear facilities into the aquatic environment. In recent years, a large number of papers have been published on the uptake, concentration and release of radioactive material by aquatic organisms. However, radiation experiments on fish, a major source of food for human consumption, are still very rare and mostly restricted to studies on the effect of irradiation on eggs and larvae. Since the study of the radiation effect on living aquatic organisms, particularly fish, is important in connection with the problems of preserving water resources for the benefit of mankind, the work presented here has been done to ascertain the effect of varying dose-levels of gamma irradiation on two common Egyptian Nile fish species, the catfish Clarias lazera and the Tilapia nilotica. Investigations carried out on Clarias lazera involved blood and muscle analyses as well as growth rate measurements. The results obtained showed impaired haematological levels, changes in weight of muscle proteins and, chiefly, retardation in growth rate. Investigations carried out on Tilapia nilotica revealed changes in the activity of certain digestive enzyme systems, glucose level in blood and concentration of the glycogen store in liver and muscles. In discussing the results obtained the authors have taken the relevant literature into consideration. (author)

  20. Levels of physical dependence on tobacco among adolescent smokers in Cyprus.

    Science.gov (United States)

    Christophi, Costas A; Pampaka, Despina; Paisi, Martha; Ioannou, Solonas; DiFranza, Joseph R

    2016-09-01

    The purpose of this study is to assess tobacco dependence among Cypriot adolescents and examine its association to cigarette consumption and attitudes towards smoking. The current study used cross-sectional data from the 2011 Cyprus Global Youth Tobacco Survey which adopted multistage cluster sampling methods to select adolescents registered in middle and high schools in Cyprus. Tobacco use, physical dependence on tobacco, and attitudes towards tobacco use were measured in 187 adolescents aged 13-18years old who reported that they had smoked at least once in the preceding 30days. Physical dependence was assessed using the Levels of Physical Dependence scale. Physical dependence was present in 86% of the adolescent smokers. The mean latency to needing among smokers in the highest dependence group was 101h. Significant associations were observed between physical dependence and the perceived difficulty in quitting (OR=13.1, 95% CI: 4.0, 43.0) as well as the expectation to continue smoking for the next five years (OR=3.3, 95% CI: 1.3, 8.4). Significant associations were also observed between physical dependence and the number of smoking days per month, daily smoking, daily cigarette consumption, lifetime cigarette consumption, and perceived difficulty in abstaining from smoking for one week. Physical dependence provides a symptom-based approach to assess dependence and it is a strong predictor of adolescents' perceptions of their ability to quit or to refrain from smoking for a week. Physical dependence on tobacco was highly prevalent among adolescent smokers in Cyprus and it was associated with greater perceived difficulty in quitting. Interventions targeting adolescent smoking must account for the high prevalence of physical dependence. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Synchronization to metrical levels in music depends on low-frequency spectral components and tempo.

    Science.gov (United States)

    Burger, Birgitta; London, Justin; Thompson, Marc R; Toiviainen, Petri

    2017-07-15

    Previous studies have found relationships between music-induced movement and musical characteristics on more general levels, such as tempo or pulse clarity. This study focused on synchronization abilities to music of finely-varying tempi and varying degrees of low-frequency spectral change/flux. Excerpts from six classic Motown/R&B songs at three different tempos (105, 115, and 130 BPM) were used as stimuli in this experiment. Each was then time-stretched by a factor of 5% with regard to the original tempo, yielding a total of 12 stimuli that were presented to 30 participants. Participants were asked to move along with the stimuli while being recorded with an optical motion capture system. Synchronization analysis was performed relative to the beat and the bar level of the music and four body parts. Results suggest that participants synchronized different body parts to specific metrical levels; in particular, vertical movements of hip and feet were synchronized to the beat level when the music contained large amounts of low-frequency spectral flux and had a slower tempo, while synchronization of head and hands was more tightly coupled to the weak flux stimuli at the bar level. Synchronization was generally more tightly coupled to the slower versions of the same stimuli, while synchronization showed an inverted u-shape effect at the bar level as tempo increased. These results indicate complex relationships between musical characteristics, in particular regarding metrical and temporal structure, and our ability to synchronize and entrain to such musical stimuli.

  2. Local order dependent impurity levels in alloy semiconductors

    International Nuclear Information System (INIS)

    Silva, C.E.T.G. da; Ecole Normale Superieure, 75 - Paris

    1981-01-01

    We develop a one band/may sites model for an isoelectronic impurity in a semiconductor alloy. The cluster-Bethe-lattice approximation is used to study the dependence of the impurity energy level upon the short range order (SRO) of the alloy. The Kikuchi parametrization is used to describe the latter. We take into account diagonal disorder only, with possible off-diagonal relaxation around the impurity site. All the inequivalent clusters of the impurity site and its first nearest neighbours are considered, thus including the important short range alloy potential fluctuations. Results are presented for the local density of impurity states, for different degrees of SRO in the alloy. (Author) [pt

  3. Brain response to food cues varying in portion size is associated with individual differences in the portion size effect in children

    NARCIS (Netherlands)

    Keller, Kathleen L.; English, Laural K.; Fearnbach, S.N.; Lasschuijt, Marlou; Anderson, Kaitlin; Bermudez, Maria; Fisher, Jennifer O.; Rolls, Barbara J.; Wilson, Stephen J.

    2018-01-01

    Large portions promote intake of energy dense foods (i.e., the portion size effect–PSE), but the neurobiological drivers of this effect are not known. We tested the association between blood oxygen level dependent (BOLD) brain response to food images varied by portion size (PS) and energy density

  4. Identification of Time-Varying Pilot Control Behavior in Multi-Axis Control Tasks

    Science.gov (United States)

    Zaal, Peter M. T.; Sweet, Barbara T.

    2012-01-01

    Recent developments in fly-by-wire control architectures for rotorcraft have introduced new interest in the identification of time-varying pilot control behavior in multi-axis control tasks. In this paper a maximum likelihood estimation method is used to estimate the parameters of a pilot model with time-dependent sigmoid functions to characterize time-varying human control behavior. An experiment was performed by 9 general aviation pilots who had to perform a simultaneous roll and pitch control task with time-varying aircraft dynamics. In 8 different conditions, the axis containing the time-varying dynamics and the growth factor of the dynamics were varied, allowing for an analysis of the performance of the estimation method when estimating time-dependent parameter functions. In addition, a detailed analysis of pilots adaptation to the time-varying aircraft dynamics in both the roll and pitch axes could be performed. Pilot control behavior in both axes was significantly affected by the time-varying aircraft dynamics in roll and pitch, and by the growth factor. The main effect was found in the axis that contained the time-varying dynamics. However, pilot control behavior also changed over time in the axis not containing the time-varying aircraft dynamics. This indicates that some cross coupling exists in the perception and control processes between the roll and pitch axes.

  5. Vitamin B12 and folate levels in normal population of northern Pakistan

    International Nuclear Information System (INIS)

    Madood-ul-mannan; Anwar, M.; Saleem, M.; Waqar, A.; Ahmad, M.

    1990-01-01

    Diagnosis of vitamin B12 or folate deficiency can not be made unless reference ranges of these vitamins in a given population are known. These serum levels depend upon the dietary intake of these vitamins which in turn depends upon the availability of foods containing these vitamins and the methods of cooking/processing. The latter vary in different populations. Therefore serum level of these vitamins would vary in different populations. Serum levels of vitamin B12 and folate were estimated by radioimmunoassay technique in 30 normal subjects of different age groups. The levels of vitamin B12 were found to be 215.2 pg/ml and that of folate 3.9 ng/ml. These values are much lower than those described for European population. It is therefore concluded that the cut off point of the levels of these vitamins should be different than the European figures. (author)

  6. Does Shyness Vary According to Attained Social Roles? Trends Across Age Groups in a Large British Sample.

    Science.gov (United States)

    Van Zalk, Nejra; Lamb, Michael E; Jason Rentfrow, Peter

    2017-12-01

    The current study investigated (a) how a composite measure of shyness comprising introversion and neuroticism relates to other well-known constructs involving social fears, and (b) whether mean levels of shyness vary for men and women depending on the adoption of various social roles. Study 1 used a sample of 211 UK participants aged 17-70 (64% female; M age  = 47.90). Study 2 used data from a large cross-sectional data set with UK participants aged 17-70 (N target  = 552,663; 64% female; M age  = 34.19 years). Study 1 showed that shyness measured as a composite of introversion and neuroticism was highly correlated with other constructs involving social fears. Study 2 indicated that, controlling for various sociodemographic variables, females appeared to have higher levels, whereas males appeared to have lower levels of shyness. Males and females who were in employment had the lowest shyness levels, whereas those working in unskilled jobs had the highest levels and people working in sales the lowest levels of shyness. Participants in relationships had lower levels of shyness than those not in relationships, but parenthood was not associated with shyness. Mean levels of shyness are likely to vary according to adopted social roles, gender, and age. © 2016 Wiley Periodicals, Inc.

  7. Level of khat dependence, use patterns, and psychosocial correlates in Yemen: a cross-sectional investigation.

    Science.gov (United States)

    Nakajima, Motohiro; Hoffman, Richard; al'Absi, Mustafa

    2017-05-01

    Chronic khat use is associated with negative health consequences. However, no study has fully characterized individuals who are khat dependent. This paper examines socio-demographic and psychosocial correlates of adult khat dependence. A total of 270 khat users (129 women) in Yemen completed face-to-face interviews and provided demographic information and data on patterns of khat use, subjective mood, and sleep quality. The Severity of Dependence Scale-Khat (SDS-khat) was used to assess level of khat dependence. A series of analysis of variance was conducted. Khat users, on average, used khat for 5.2 hours a day (SD = 2.3) for 5.7 days a week (SD = 2.0). Individuals who screened positive for khat dependence reported longer duration of khat sessions per day, higher frequency of khat use per week, greater levels of negative mood and sleep disturbances, and were more likely to endorse physical symptoms after khat use (P < 0.05). Future research should elucidate mechanisms responsible for khat dependence symptomatology.

  8. Three-dimensional orientation and location-dependent varying rules of radiographic angles of the acetabular cup.

    Science.gov (United States)

    Zhao, Jing-Xin; Su, Xiu-Yun; Zhao, Zhe; Xiao, Ruo-Xiu; Zhang, Li-Cheng; Tang, Pei-Fu

    2018-02-17

    The aim of this study is to demonstrate the varying rules of radiographic angles following varying three-dimensional (3D) orientations and locations of cup using an accurate mathematical model. A cone model is established to address the quantitative relationship between the opening circle of cup and its ellipse projection on radiograph. The varying rules of two-dimensional (2D) radiographic anteversion (RA) and inclination (RI) angles can be analyzed. When the centre of cup is located above X-ray source, with proper 3D RI/RA angles, 2D RA angle can be equal to its 3D counterpart, and 2D RI angle is usually greater than its 3D counterpart. Except for the original point on hip-centered anterior-posterior radiograph, there is no area on radiograph where both 2D RA and RI angles are equal to their 3D counterparts simultaneously. This study proposes an innovative model for accurately explaining how 2D RA/RI angles of cup are varying following different 3D RA/RI angles and location of cup. The analysis results provide clinicians an intuitive grasp of knowledge about 2D RA/RI angles greater or smaller than their 3D counterparts post-operatively. The established model may allow determining the effects of pelvic rotations on 2D radiographic angles of cup.

  9. Water level effects on breaking wave setup for Pacific Island fringing reefs

    Science.gov (United States)

    Becker, J. M.; Merrifield, M. A.; Ford, M.

    2014-02-01

    The effects of water level variations on breaking wave setup over fringing reefs are assessed using field measurements obtained at three study sites in the Republic of the Marshall Islands and the Mariana Islands in the western tropical Pacific Ocean. At each site, reef flat setup varies over the tidal range with weaker setup at high tide and stronger setup at low tide for a given incident wave height. The observed water level dependence is interpreted in the context of radiation stress gradients specified by an idealized point break model generalized for nonnormally incident waves. The tidally varying setup is due in part to depth-limited wave heights on the reef flat, as anticipated from previous reef studies, but also to tidally dependent breaking on the reef face. The tidal dependence of the breaking is interpreted in the context of the point break model in terms of a tidally varying wave height to water depth ratio at breaking. Implications for predictions of wave-driven setup at reef-fringed island shorelines are discussed.

  10. Defects level evaluation of LiTiZn ferrite ceramics using temperature dependence of initial permeability

    Science.gov (United States)

    Malyshev, A. V.; Petrova, A. B.; Sokolovskiy, A. N.; Surzhikov, A. P.

    2018-06-01

    The method for evaluating the integral defects level and chemical homogeneity of ferrite ceramics based on temperature dependence analysis of initial permeability is suggested. A phenomenological expression for the description of such dependence was suggested and an interpretation of its main parameters was given. It was shown, that the main criterion of the integral defects level of ferrite ceramics is relation of two parameters correlating with elastic stress value in a material. An indicator of structural perfection can be a maximum value of initial permeability close to Curie point as well. The temperature dependences of initial permeability have analyzed for samples sintered in laboratory conditions and for the ferrite industrial product. The proposed method allows controlling integral defects level of the soft ferrite products and has high sensitivity compare to typical X-ray methods.

  11. Haloperidol plasma levels in relation to antimanic effect

    DEFF Research Database (Denmark)

    Gjerris, Annette; Bech, P.; Christensen, Christian Broen

    2016-01-01

    n the treatment of mania, lithium (Li) has been found in several controlled studies as clearly superior to placebo, but haloperidol, when compared to Li, seems to be faster acting, at least with regard to motor activity (Shopsin et al., 1975). Hence, haloperidol has increasingly been recommended...... as the antimanic drug of choice (Shaw, 1979). However, the recommended dose of haloperidol for mania varies extremely, from 4 mg to 100 mg daily (Hollister, 1978). The haloperidol dose required obviously depends on the severity of the manic state, but might also depend on the metabolism of the drug, which varies...... in different patients (Forsman, 1977). To our knowledge the relationship between plasma levels of haloperidol and antimanic effect has not been evaluated. In the present study we have measured plasma levels of haloperidol in manic patients treated with a fixed haloperidol dose and examined the relationship...

  12. Alcohol use and related consequences among students with varying levels of involvement in college athletics.

    Science.gov (United States)

    Leichliter, J S; Meilman, P W; Presley, C A; Cashin, J R

    1998-05-01

    Alcohol use, binge drinking, and substance abuse-related consequences among students with varying levels of participation in intercollegiate athletics were examined. Between October 1994 and May 1996, 51,483 students at 125 institutions answered questions about their involvement in athletics, ranging from noninvolvement to participant to leadership positions, on the long form of the Core Alcohol and Drug Survey. In comparisons with nonathletes, both male and female athletes consumed significantly more alcohol per week, engaged in binge drinking more often, and suffered more adverse consequences from their substance use. No support was found for the hypothesis that athletic leaders were more responsible than other team participants in using alcohol. Male team leaders appeared to be at significantly greater risk than female team leaders; they also consumed more alcohol, binged more often, and suffered more consequences than other team members.

  13. Phosphorus sorption capacity of biochars varies with biochar type and salinity level.

    Science.gov (United States)

    Dugdug, Abdelhafid Ahmed; Chang, Scott X; Ok, Yong Sik; Rajapaksha, Anushka Upamali; Anyia, Anthony

    2018-02-10

    biochar. We conclude that the P sorption capacity of the studied biochars is dependent on the concentration of the soluble element in the biochar, which is dependent on the biochar type, as well as the salinity level in the aqueous solution.

  14. Turbulent piloted partially-premixed flames with varying levels of O2/N2: stability limits and PDF calculations

    Science.gov (United States)

    Juddoo, Mrinal; Masri, Assaad R.; Pope, Stephen B.

    2011-12-01

    This paper reports measured stability limits and PDF calculations of piloted, turbulent flames of compressed natural gas (CNG) partially-premixed with either pure oxygen, or with varying levels of O2/N2. Stability limits are presented for flames of CNG fuel premixed with up to 20% oxygen as well as CNG-O2-N2 fuel where the O2 content is varied from 8 to 22% by volume. Calculations are presented for (i) Sydney flame B [Masri et al. 1988] which uses pure CNG as well as flames B15 to B25 where the CNG is partially-premixed with 15-25% oxygen by volume, respectively and (ii) Sandia methane-air (1:3 by volume) flame E [Barlow et al. 2005] as well as new flames E15 and E25 that are partially-premixed with 'reconstituted air' where the O2 content in nitrogen is 15 and 25% by volume, respectively. The calculations solve a transported PDF of composition using a particle-based Monte Carlo method and employ the EMST mixing model as well as detailed chemical kinetics. The addition of oxygen to the fuel increases stability, shortens the flames, broadens the reaction zone, and shifts the stoichiometric mixture fraction towards the inner side of the jet. It is found that for pure CNG flames where the reaction zone is narrow (∼0.1 in mixture fraction space), the PDF calculations fail to reproduce the correct level of local extinction on approach to blow-off. A broadening in the reaction zone up to about 0.25 in mixture fraction space is needed for the PDF/EMST approach to be able to capture these finite-rate chemistry effects. It is also found that for the same level of partial premixing, increasing the O2/N2 ratio increases the maximum levels of CO and NO but shifts the peak to richer mixture fractions. Over the range of oxygenation investigated here, stability limits have shown to improve almost linearly with increasing oxygen levels in the fuel and with increasing the contribution of release rate from the pilot.

  15. Marriage is a dependent risk factor for mortality of colon adenocarcinoma without a time-varying effect.

    Science.gov (United States)

    Liu, Minling; Li, Lixian; Yu, Wei; Chen, Jie; Xiong, Weibin; Chen, Shuang; Yu, Li

    2017-03-21

    It has been well recognized that the effects of many prognostic factors could change during long-term follow-up. Although marriage has been proven to be a significant prognostic factor for the survival of colon cancer, whether the effect of marriage is constant with time remain unknown. This study analyzed the impact of marital status on the mortality of colon cancer patients with an extended Cox model that allowed for time-varying effects. We identified 71,955 patients who underwent colectomy between 2004 and 2009 to treat colon adenocarcinoma from the Surveilance, Epidemiology and End Results Database. The multivariate extended Cox model was used to evaluate the effect of marital status on all-cause mortality, while the Fine-Gray competing risks model was used for colon cancer-specific mortality, with death from other causes as the competing risk. The unmarried patients carried a 1.37-fold increased risk of all-cause mortality compared with the married patients (95%CI: 1.33-1.40; pMarriage is a dependent prognosis factor for survival of surgically treated colon adenocarcinoma patients. Psychological interventions are suggested to improve receipt of treatment among unmarried patients, as their poor survival may be due to the inefficient treatment.

  16. Age and dosage-level dependence of radium retention in beagles

    International Nuclear Information System (INIS)

    Parks, N.J.; Pool, R.R.; Williams, J.R.; Wolf, H.G.

    1978-01-01

    Radium retention was measured over the lifespan of 46 beagles exposed by eight semimonthly injections at 60 to 160, 120 to 220, or 435 to 535 days of age. Injection dosage levels ranged from 0.37 to 10 μCi of 226 Ra/kg. The fractional retention of each animal is described in terms of a modified power function, R = [(t + d)/d] - /sup b/. Young adult beagles (approximately equal to 10 kg) injected at a mean age (A) of 485 days with 226 Ra at dosage levels of 10, 3.3, 1.11, and 0.37 μCi/kg had mean values for d and b of [0.897; 0.187], [2.015; 0.206], [2.778; 0.257], and [3.894; 0.274], respectively. Juvenile beagles injected with 10 μCi/kg at A = 110 days (average weight approximately equal to 6 kg) and at A = 170 days (average weight approximately equal to 10 kg) had mean values for d and b of [137; 0.277] and [5.53; 0.086], respectively. The d values are geometric means and the units are days; b values are arithmetic means. The formula for deriving the age-dependent retention function for dogs is given. The beagle results were correlated with human data in terms of age-to-equivalent fraction of adult body calcium content and were used to construct a similar age-dependent retention function for chronically exposed people. The correlation of age-dependent retention functions for beagles and humans is used to estimate scaling factors between the two species for the fraction of injected dosage associated with bone for various ages of exposure

  17. Vesicle biomechanics in a time-varying magnetic field.

    Science.gov (United States)

    Ye, Hui; Curcuru, Austen

    2015-01-01

    Cells exhibit distortion when exposed to a strong electric field, suggesting that the field imposes control over cellular biomechanics. Closed pure lipid bilayer membranes (vesicles) have been widely used for the experimental and theoretical studies of cellular biomechanics under this electrodeformation. An alternative method used to generate an electric field is by electromagnetic induction with a time-varying magnetic field. References reporting the magnetic control of cellular mechanics have recently emerged. However, theoretical analysis of the cellular mechanics under a time-varying magnetic field is inadequate. We developed an analytical theory to investigate the biomechanics of a modeled vesicle under a time-varying magnetic field. Following previous publications and to simplify the calculation, this model treated the inner and suspending media as lossy dielectrics, the membrane thickness set at zero, and the electric resistance of the membrane assumed to be negligible. This work provided the first analytical solutions for the surface charges, electric field, radial pressure, overall translational forces, and rotational torques introduced on a vesicle by the time-varying magnetic field. Frequency responses of these measures were analyzed, particularly the frequency used clinically by transcranial magnetic stimulation (TMS). The induced surface charges interacted with the electric field to produce a biomechanical impact upon the vesicle. The distribution of the induced surface charges depended on the orientation of the coil and field frequency. The densities of these charges were trivial at low frequency ranges, but significant at high frequency ranges. The direction of the radial force on the vesicle was dependent on the conductivity ratio between the vesicle and the medium. At relatively low frequencies (biomechanics under a time-varying magnetic field. Biological effects of clinical TMS are not likely to occur via alteration of the biomechanics of brain

  18. Matrix-dependent multigrid-homogenization for diffusion problems

    Energy Technology Data Exchange (ETDEWEB)

    Knapek, S. [Institut fuer Informatik tu Muenchen (Germany)

    1996-12-31

    We present a method to approximately determine the effective diffusion coefficient on the coarse scale level of problems with strongly varying or discontinuous diffusion coefficients. It is based on techniques used also in multigrid, like Dendy`s matrix-dependent prolongations and the construction of coarse grid operators by means of the Galerkin approximation. In numerical experiments, we compare our multigrid-homogenization method with homogenization, renormalization and averaging approaches.

  19. Lyapunov Functions to Caputo Fractional Neural Networks with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Ravi Agarwal

    2018-05-01

    Full Text Available One of the main properties of solutions of nonlinear Caputo fractional neural networks is stability and often the direct Lyapunov method is used to study stability properties (usually these Lyapunov functions do not depend on the time variable. In connection with the Lyapunov fractional method we present a brief overview of the most popular fractional order derivatives of Lyapunov functions among Caputo fractional delay differential equations. These derivatives are applied to various types of neural networks with variable coefficients and time-varying delays. We show that quadratic Lyapunov functions and their Caputo fractional derivatives are not applicable in some cases when one studies stability properties. Some sufficient conditions for stability of equilibrium of nonlinear Caputo fractional neural networks with time dependent transmission delays, time varying self-regulating parameters of all units and time varying functions of the connection between two neurons in the network are obtained. The cases of time varying Lipschitz coefficients as well as nonLipschitz activation functions are studied. We illustrate our theory on particular nonlinear Caputo fractional neural networks.

  20. Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

    International Nuclear Information System (INIS)

    Tsuji, Hirokazu; Nakajima, Hajime; Tanabe, Tatsuhiko.

    1993-09-01

    A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000degC in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the born content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000degC to 900degC. The trend observed in the tests from 900degC to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (author)

  1. Blood oxygenation level dependent (BOLD). Renal imaging. Concepts and applications; Blood Oxygenation Level Dependent (BOLD). Bildgebung der Nieren. Konzepte und Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Nissen, Johanna C.; Haneder, Stefan; Schoenberg, Stefan O.; Michaely, Henrik J. [Heidelberg Univ. Medizinische Fakultaet Mannheim (Germany). Inst. fuer Klinische Radiologie und Nuklearmedizin; Mie, Moritz B.; Zoellner, Frank G. [Heidelberg Univ. Medizinische Fakultaet Mannheim (DE). Inst. fuer Computerunterstuetzte Klinische Medizin (CKM)

    2010-07-01

    Many renal diseases as well as several pharmacons cause a change in renal blood flow and/or renal oxygenation. The blood oxygenation level dependent (BOLD) imaging takes advantage of local field inhomogeneities and is based on a T2{sup *}-weighted sequence. BOLD is a non-invasive method allowing an estimation of the renal, particularly the medullary oxygenation, and an indirect measurement of blood flow without administration of contrast agents. Thus, effects of different drugs on the kidney and various renal diseases can be controlled and observed. This work will provide an overview of the studies carried out so far and identify ways how BOLD can be used in clinical studies. (orig.)

  2. Adaptive observer-based control for an IPMC actuator under varying humidity conditions

    Science.gov (United States)

    Bernat, Jakub; Kolota, Jakub

    2018-05-01

    As ionic polymer metal composites (IPMC) are increasingly applied to mechatronic systems, many new IPMC modeling efforts have been reported in the literature. The demands of rapidly growing technology has generated interest in advancing the intrinsic actuation and sensing capabilities of IPMC. Classical IPMC applications need constant hydration to operate. On the other hand, for IPMCs operating in air, the water content of the polymer varies with the humidity level of the ambient environment, which leads to its strong humidity-dependent behavior. Furthermore, decreasing water content over time plays a crucial role in the effectiveness of IPMC. Therefore, the primary challenge of this work is to accurately model this phenomenon. The principal contribution of the paper is a new IPMC model, which considers the change of moisture content. A novel nonlinear adaptive observer is designed to determine the unknown electric potential and humidity level in the polymer membrane. This approach effectively determines the moisture content of the IPMC during long-term continuous operation in air. This subsequently allows us to develop an effective back-stepping control algorithm that considers varying moisture content. Data from experiments are presented to support the effectiveness of the observation process, which is shown in illustrative examples.

  3. On Regularly Varying and History-Dependent Convergence Rates of Solutions of a Volterra Equation with Infinite Memory

    OpenAIRE

    John A. D. Appleby

    2010-01-01

    We consider the rate of convergence to equilibrium of Volterra integrodifferential equations with infinite memory. We show that if the kernel of Volterra operator is regularly varying at infinity, and the initial history is regularly varying at minus infinity, then the rate of convergence to the equilibrium is regularly varying at infinity, and the exact pointwise rate of convergence can be determined in terms of the rate of decay of the kernel and the rate of growth of the initial history. ...

  4. Order Level Inventory Models for Deteriorating Seasonable/Fashionable Products with Time Dependent Demand and Shortages

    OpenAIRE

    Skouri, K.; Konstantaras, I.

    2009-01-01

    An order level inventory model for seasonable/fashionable products subject to a period of increasing demand followed by a period of level demand and then by a period of decreasing demand rate (three branches ramp type demand rate) is considered. The unsatisfied demand is partially backlogged with a time dependent backlogging rate. In addition, the product deteriorates with a time dependent, namely, Weibull, deterioration rate. The model is studied under the following different replenishment p...

  5. A new perspective on human health risk assessment: Development of a time dependent methodology and the effect of varying exposure durations

    International Nuclear Information System (INIS)

    Siirila, Erica R.; Maxwell, Reed M.

    2012-01-01

    We present a new Time Dependent Risk Assessment (TDRA) that stochastically considers how joint uncertainty and inter-individual variability (JUV) associated with human health risk change as a function of time. In contrast to traditional, time independent assessments of risk, this new formulation relays information on when the risk occurs, how long the duration of risk is, and how risk changes with time. Because the true exposure duration (ED) is often uncertain in a risk assessment, we also investigate how varying the magnitude of fixed size durations (ranging between 5 and 70 years) of this parameter affects the distribution of risk in both the time independent and dependent methodologies. To illustrate this new formulation and to investigate these mechanisms for sensitivity, an example of arsenic contaminated groundwater is used in conjunction with two scenarios of different environmental concentration signals resulting from rate dependencies in geochemical reactions. Cancer risk is computed and compared using environmental concentration ensembles modeled with sorption as 1) a linear equilibrium assumption (LEA) and 2) first order kinetics (Kin). Results show that the information attained in the new time dependent methodology reveals how the uncertainty in other time-dependent processes in the risk assessment may influence the uncertainty in risk. We also show that individual susceptibility also affects how risk changes in time, information that would otherwise be lost in the traditional, time independent methodology. These results are especially pertinent for forecasting risk in time, and for risk managers who are assessing the uncertainty of risk. - Highlights: ► A human health, Time Dependent Risk Assessment (TDRA) methodology is presented. ► TDRA relays information on the magnitude, duration, and fluxes of risk in time. ► Kinetic and equilibrium concentration signals show sensitivity in TDRA results. ► In the TDRA results, individual susceptibility

  6. A new perspective on human health risk assessment: Development of a time dependent methodology and the effect of varying exposure durations

    Energy Technology Data Exchange (ETDEWEB)

    Siirila, Erica R., E-mail: esiirila@mymail.mines.edu [Hydrologic Science and Engineering Program, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Department of Geology and Geological Engineering, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Maxwell, Reed M., E-mail: rmaxwell@mines.edu [Hydrologic Science and Engineering Program, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Integrated Groundwater Modeling Center (IGWMC), Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States); Department of Geology and Geological Engineering, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401 (United States)

    2012-08-01

    We present a new Time Dependent Risk Assessment (TDRA) that stochastically considers how joint uncertainty and inter-individual variability (JUV) associated with human health risk change as a function of time. In contrast to traditional, time independent assessments of risk, this new formulation relays information on when the risk occurs, how long the duration of risk is, and how risk changes with time. Because the true exposure duration (ED) is often uncertain in a risk assessment, we also investigate how varying the magnitude of fixed size durations (ranging between 5 and 70 years) of this parameter affects the distribution of risk in both the time independent and dependent methodologies. To illustrate this new formulation and to investigate these mechanisms for sensitivity, an example of arsenic contaminated groundwater is used in conjunction with two scenarios of different environmental concentration signals resulting from rate dependencies in geochemical reactions. Cancer risk is computed and compared using environmental concentration ensembles modeled with sorption as 1) a linear equilibrium assumption (LEA) and 2) first order kinetics (Kin). Results show that the information attained in the new time dependent methodology reveals how the uncertainty in other time-dependent processes in the risk assessment may influence the uncertainty in risk. We also show that individual susceptibility also affects how risk changes in time, information that would otherwise be lost in the traditional, time independent methodology. These results are especially pertinent for forecasting risk in time, and for risk managers who are assessing the uncertainty of risk. - Highlights: Black-Right-Pointing-Pointer A human health, Time Dependent Risk Assessment (TDRA) methodology is presented. Black-Right-Pointing-Pointer TDRA relays information on the magnitude, duration, and fluxes of risk in time. Black-Right-Pointing-Pointer Kinetic and equilibrium concentration signals show

  7. Comparison of plant nutrient levels between compost from Sky loo ...

    African Journals Online (AJOL)

    Recent scholars have highlighted the benefit of harvesting compost from eco-san toilets for application as plant nutrients. However, levels of nutrients in eco-san compost may vary depending on the type of toilet and also the type of top soil in a particular geographical region. This study compared levels of nitrogen, ...

  8. State space modeling of time-varying contemporaneous and lagged relations in connectivity maps.

    Science.gov (United States)

    Molenaar, Peter C M; Beltz, Adriene M; Gates, Kathleen M; Wilson, Stephen J

    2016-01-15

    Most connectivity mapping techniques for neuroimaging data assume stationarity (i.e., network parameters are constant across time), but this assumption does not always hold true. The authors provide a description of a new approach for simultaneously detecting time-varying (or dynamic) contemporaneous and lagged relations in brain connectivity maps. Specifically, they use a novel raw data likelihood estimation technique (involving a second-order extended Kalman filter/smoother embedded in a nonlinear optimizer) to determine the variances of the random walks associated with state space model parameters and their autoregressive components. The authors illustrate their approach with simulated and blood oxygen level-dependent functional magnetic resonance imaging data from 30 daily cigarette smokers performing a verbal working memory task, focusing on seven regions of interest (ROIs). Twelve participants had dynamic directed functional connectivity maps: Eleven had one or more time-varying contemporaneous ROI state loadings, and one had a time-varying autoregressive parameter. Compared to smokers without dynamic maps, smokers with dynamic maps performed the task with greater accuracy. Thus, accurate detection of dynamic brain processes is meaningfully related to behavior in a clinical sample. Published by Elsevier Inc.

  9. Spin-dependent level density in interacting Boson-Fermion-Fermion model of the Odd-Odd Nucleus 196Au

    International Nuclear Information System (INIS)

    Kabashi, S.; Bekteshi, S.; Ahmetaj, S.; Shaqiri, Z.

    2009-01-01

    The level density of the odd-odd nucleus 196 Au is investigated in the interacting boson-fermion-fermion model (IBFFM) which accounts for collectivity and complex interaction between quasiparticle and collective modes.The IBFFM spin-dependent level densities show high-spin reduction with respect to Bethe formula.This can be well accounted for by a modified spin-dependent level density formula. (authors)

  10. Gender Differences in the Effect of Tobacco Use on Brain Phosphocreatine Levels in Methamphetamine Dependent Subjects

    Science.gov (United States)

    Sung, Young-Hoon; Yurgelun-Todd, Deborah A.; Kondo, Douglas G.; Shi, Xian-Feng; Lundberg, Kelly J.; Hellem, Tracy L.; Huber, Rebekah S.; McGlade, Erin C.; Jeong, Eun-Kee; Renshaw, Perry F.

    2015-01-01

    Background A high prevalence of tobacco smoking has been observed in methamphetamine users, but there have been no in vivo brain neurochemistry studies addressing gender effects of tobacco smoking in methamphetamine users. Methamphetamine addiction is associated with increased risk of depression and anxiety in females. There is increasing evidence that selective analogues of nicotine, a principal active component of tobacco smoking, may improve depression and cognitive performance in animals and humans. Objectives To investigate the effects of tobacco smoking and gender on brain phosphocreatine (PCr) levels, a marker of brain energy metabolism reported to be reduced in methamphetamine-dependent subjects. Methods Thirty female and twenty-seven male methamphetamine-dependent subjects were evaluated with phosphorus-31 magnetic resonance spectroscopy (31P-MRS) to measure PCr levels within the pregenual anterior cingulate, which has been implicated in methamphetamine neurotoxicity. Results Analysis of covariance revealed that there were statistically significant slope (PCr versus lifetime amount of tobacco smoking) differences between female and male methamphetamine-dependent subjects (p=0.03). In females, there was also a statistically significant interaction between lifetime amounts of tobacco smoking and methamphetamine in regard to PCr levels (p=0.01), which suggests that tobacco smoking may have a more significant positive impact on brain PCr levels in heavy, as opposed to light to moderate, methamphetamine-dependent females. Conclusion These results indicate that tobacco smoking has gender-specific effects in terms of increased anterior cingulate high energy PCr levels in methamphetamine-dependent subjects. Cigarette smoking in methamphetamine-dependent women, particularly those with heavy methamphetamine use, may have a potentially protective effect upon neuronal metabolism. PMID:25871447

  11. Influence of postnatal glucocorticoids on hippocampal-dependent learning varies with elevation patterns and administration methods.

    Science.gov (United States)

    Claflin, Dragana I; Schmidt, Kevin D; Vallandingham, Zachary D; Kraszpulski, Michal; Hennessy, Michael B

    2017-09-01

    Recent interest in the lasting effects of early-life stress has expanded to include effects on cognitive performance. An increase in circulating glucocorticoids is induced by stress exposure and glucocorticoid effects on the hippocampus likely underlie many of the cognitive consequences. Here we review studies showing that corticosterone administered to young rats at the conclusion of the stress-hyporesponsiveness period affects later performance in hippocampally-mediated trace eyeblink conditioning. The nature and even direction of these effects varies with the elevation patterns (level, duration, temporal fluctuation) achieved by different administration methods. We present new time course data indicating that constant glucocorticoid elevations generally corresponded with hippocampus-mediated learning deficits, whereas acute, cyclical elevations corresponded with improved initial acquisition. Sensitivity was greater for males than for females. Further, changes in hippocampal neurogenesis paralleled some but not all effects. The findings demonstrate that specific patterns of glucocorticoid elevation produced by different drug administration procedures can have markedly different, sex-specific consequences on basic cognitive performance and underlying hippocampal physiology. Implications of these findings for glucocorticoid medications prescribed in childhood are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Does care to dependent elderly people living at home increase their mental health?

    OpenAIRE

    Thomas Barnay; Sandrine Juin

    2014-01-01

    In France, the number of dependent elderly should d ouble by 2060. It is thus important to address the well-being of this growing share of the population. This work aims at estimating the effects of informal care and formal care on the mental health of dependent elderly. Furthermore, we allow the effect of care to vary de pending on the level of dependence, the gender of the dependent elderly and the relationship between the elderly and the primary informal caregiver. Many theoretical models ...

  13. Differentiation of Volatile Profiles from Stockpiled Almonds at Varying Relative Humidity Levels Using Benchtop and Portable GC-MS.

    Science.gov (United States)

    Beck, John J; Willett, Denis S; Gee, Wai S; Mahoney, Noreen E; Higbee, Bradley S

    2016-12-14

    Contamination by aflatoxin, a toxic metabolite produced by Aspergillus fungi ubiquitous in California almond and pistachio orchards, results in millions of dollars of lost product annually. Current detection of aflatoxin relies on destructive, expensive, and time-intensive laboratory-based methods. To explore an alternative method for the detection of general fungal growth, volatile emission profiles of almonds at varying humidities were sampled using both static SPME and dynamic needle-trap SPE followed by benchtop and portable GC-MS analysis. Despite the portable SPE/GC-MS system detecting fewer volatiles than the benchtop system, both systems resolved humidity treatments and identified potential fungal biomarkers at extremely low water activity levels. This ability to resolve humidity levels suggests that volatile profiles from germinating fungal spores could be used to create an early warning, nondestructive, portable detection system of fungal growth.

  14. Information entropy of a time-dependent three-level trapped ion interacting with a laser field

    International Nuclear Information System (INIS)

    Abdel-Aty, Mahmoud

    2005-01-01

    Trapped and laser-cooled ions are increasingly used for a variety of modern high-precision experiments, frequency standard applications and quantum information processing. Therefore, in this communication we present a comprehensive analysis of the pattern of information entropy arising in the time evolution of an ion interacting with a laser field. A general analytic approach is proposed for a three-level trapped-ion system in the presence of the time-dependent couplings. By working out an exact analytic solution, we conclusively analyse the general properties of the von Neumann entropy and quantum information entropy. It is shown that the information entropy is affected strongly by the time-dependent coupling and exhibits long time periodic oscillations. This feature attributed to the fact that in the time-dependent region Rabi oscillation is time dependent. Using parameters corresponding to a specific three-level ionic system, a single beryllium ion in a RF-(Paul) trap, we obtain illustrative examples of some novel aspects of this system in the dynamical evolution. Our results establish an explicit relation between the exact information entropy and the entanglement between the multi-level ion and the laser field. We show that different nonclassical effects arise in the dynamics of the ionic population inversion, depending on the initial states of the vibrational motion/field and on the values of Lamb-Dicke parameter η

  15. New varying speed of light theories

    International Nuclear Information System (INIS)

    Magueijo, Joao

    2003-01-01

    We review recent work on the possibility of a varying speed of light (VSL). We start by discussing the physical meaning of a varying-c, dispelling the myth that the constancy of c is a matter of logical consistency. We then summarize the main VSL mechanisms proposed so far: hard breaking of Lorentz invariance; bimetric theories (where the speeds of gravity and light are not the same); locally Lorentz invariant VSL theories; theories exhibiting a colour-dependent speed of light; varying-c induced by extra dimensions (e.g. in the brane-world scenario); and field theories where VSL results from vacuum polarization or CPT violation. We show how VSL scenarios may solve the cosmological problems usually tackled by inflation, and also how they may produce a scale-invariant spectrum of Gaussian fluctuations, capable of explaining the WMAP data. We then review the connection between VSL and theories of quantum gravity, showing how 'doubly special' relativity has emerged as a VSL effective model of quantum space-time, with observational implications for ultra-high energy cosmic rays (UHECRs) and gamma ray bursts. Some recent work on the physics of 'black' holes and other compact objects in VSL theories is also described, highlighting phenomena associated with spatial (as opposed to temporal) variations in c. Finally, we describe the observational status of the theory. The evidence is currently slim-redshift dependence in the atomic fine structure, anomalies with UHECRs, and (to a much lesser extent) the acceleration of the universe and the WMAP data. The constraints (e.g. those arising from nucleosynthesis or geological bounds) are tight but not insurmountable. We conclude with the observational predictions of the theory and the prospects for its refutation or vindication

  16. Ghrelin system in alcohol-dependent subjects: role of plasma ghrelin levels in alcohol drinking and craving.

    Science.gov (United States)

    Leggio, Lorenzo; Ferrulli, Anna; Cardone, Silvia; Nesci, Antonio; Miceli, Antonio; Malandrino, Noemi; Capristo, Esmeralda; Canestrelli, Benedetta; Monteleone, Palmiero; Kenna, George A; Swift, Robert M; Addolorato, Giovanni

    2012-03-01

    Animal studies suggest that the gut-brain peptide ghrelin plays an important role in the neurobiology of alcohol dependence (AD). Human studies show an effect of alcohol on ghrelin levels and a correlation between ghrelin levels and alcohol craving in alcoholics. This investigation consisted of two studies. Study 1 was a 12-week study with alcohol-dependent subjects, where plasma ghrelin determinations were assessed four times (T0-T3) and related to alcohol intake and craving [Penn Alcohol Craving Score (PACS) and Obsessive Compulsive Drinking Scale (OCDS)]. Serum growth hormone levels and assessment of the nutritional/metabolic status were also performed. Study 2 was a pilot case-control study to assess ghrelin gene polymorphisms (Arg51Gln and Leu72Met) in alcohol-dependent individuals. Study 1 showed no significant differences in ghrelin levels in the whole sample, while there was a statistical difference for ghrelin between non-abstinent and abstinent subjects. Baseline ghrelin levels were significantly and positively correlated with the PACS score at T1 and with all craving scores both at T2 and T3 (PACS, OCDS, obsessive and compulsive OCDS subscores). In Study 2, although there was a higher frequency of the Leu72Met ghrelin gene polymorphism in alcohol-dependent individuals, the distribution between healthy controls and alcohol dependent individuals was not statistically significant. This investigation suggests that ghrelin is potentially able to affect alcohol-seeking behaviors, such as alcohol drinking and craving, representing a new potential neuropharmacological target for AD. © 2011 The Authors, Addiction Biology © 2011 Society for the Study of Addiction.

  17. Steady shear viscosity of stirred yoghurts with varying ropiness

    NARCIS (Netherlands)

    van Marle, M.E.; van Marle, M.E.; van den Ende, Henricus T.M.; de Kruif, C.G.; de Kruif, C.G.; Mellema, J.

    1999-01-01

    Stirred yogurt was viewed as a concentrated dispersion of aggregates consisting of protein particles. The steady-shear behavior of three types of stirred yogurt with varying ropiness was investigated experimentally. To describe the shear-dependent viscosity, a microrheological model was used which

  18. Distribution and mobility of omega 3 fatty acids in rainbow trout fed varying levels and types of dietary lipid.

    Science.gov (United States)

    Castledine, A J; Buckley, J T

    1980-04-01

    The availability of essential fatty acids in fish neutral lipid to tissue phospholipids was determined under conditions of adequate and inadequate essential fatty acid intake as well as during fasting. Juvenile rainbow trout were fed a semi-purified diet containing varying levels of cod liver oil, with or without supplementary olein. Fatty acid analysis indicated that in all treatments the neutral lipid pool was not turned over during feeding but was enhanced by exogenous or endogenously synthesized fatty acids. Fish that received diets devoid of essential fatty acids maintained virtually all of the docosahexenoic acid originally present in each lipid pool. Fish fed diets containing essential fatty acids deposited them in proportion to the dietary levels. After a 4-week fast, no change was noted in the relative levels of fatty acids in neutral lipid indicating that all fatty acids in neutral lipid were catabolized equally--including essential fatty acids. During fasting there was a selective retention of docosahexenoic and linoleic acids in the phospholipid pool.

  19. DEPENDENCE OF COUNTRY RISK COMPARED TO THE FOREIGN DEBT LEVEL

    Directory of Open Access Journals (Sweden)

    Angelica BĂCESCU-CĂRBUNARU

    2012-11-01

    Full Text Available The article presents some of the fundamental aspects of country risk’dependence compared to foreign debt level. Starting from external debt burden we analyze the usage of foreign loans, foreign debt bearing capacity as well as the availability of data regarding the external debt. Country risk represents the exposure to losses which may occur in a business with a foreign partner, caused by specific events that are, at least partially, controlled by the partner country’ government. Macroeconomic analysis of economic and financial component of country risk involves how this risk is influenced by government policy, by the economic role of government, bypricing strategies, investment priorities, financial structures, macroeconomic policy, by the ability to obtain foreign funds, the level of external debt as well as the liquidity and cash flows in that country.

  20. On Regularly Varying and History-Dependent Convergence Rates of Solutions of a Volterra Equation with Infinite Memory

    Directory of Open Access Journals (Sweden)

    Appleby JohnAD

    2010-01-01

    Full Text Available We consider the rate of convergence to equilibrium of Volterra integrodifferential equations with infinite memory. We show that if the kernel of Volterra operator is regularly varying at infinity, and the initial history is regularly varying at minus infinity, then the rate of convergence to the equilibrium is regularly varying at infinity, and the exact pointwise rate of convergence can be determined in terms of the rate of decay of the kernel and the rate of growth of the initial history. The result is considered both for a linear Volterra integrodifferential equation as well as for the delay logistic equation from population biology.

  1. Comparison of adult physical activity levels in three Swiss alpine communities with varying access to motorized transportation.

    Science.gov (United States)

    Dombois, Oliver Thommen; Braun-Fahrländer, Charlotte; Martin-Diener, Eva

    2007-09-01

    To compare physical activity levels of residents of three Swiss alpine communities with varying access to motorized transport and to investigate whether socio-demographic factors, the settlement structure or means of transport affect these levels. Between January and February 2004 a computer assisted telephone interview was conducted with 901 randomly selected adults aged 18 years or older living in three Swiss alpine communities. In particular, information on moderate and vigorous intensity physical activities and on transport behaviour was collected. Respondents were categorized as 'sufficiently active' or 'insufficiently active' according to self-reported physical activity. People living in community 1 without access to motorized traffic were significantly more likely to be sufficiently active (Sex- and age-adjusted prevalences of sufficient total physical activity, 43.9% 95% CI: 38.3%-49.8%) compared to individuals living in the other two communities (community 2: 35.9%, 95% CI: 30.6%-41.6%, community 3: 32.7%, 95% CI: 27.5%-38.3%). The differences were due to higher levels of moderate physical activities. Vigorous physical activity levels did not differ between the communities. Community differences were explained by passive means of transport to work and for leisure time activities. Although the environment encountered in the three alpine communities is generally conducive to physical activity the majority of the participants did not achieve recommended activity levels. Passive mode of transport to work and during leisure time was strongly associated with insufficient total physical activity. Walking and cycling for transportation is thus a promising approach to promote health enhancing physical activity.

  2. The BDNF Val66Met polymorphism and plasma brain-derived neurotrophic factor levels in Han Chinese heroin-dependent patients.

    Science.gov (United States)

    Chen, Shiou-Lan; Lee, Sheng-Yu; Chang, Yun-Hsuan; Wang, Tzu-Yun; Chen, Shih-Heng; Chu, Chun-Hsien; Chen, Po See; Yang, Yen Kuang; Hong, Jau-Shyong; Lu, Ru-Band

    2015-02-02

    BDNF and its gene polymorphism may be important in synaptic plasticity and neuron survival, and may become a key target in the physiopathology of long-term heroin use. Thus, we investigated the relationships between brain-derived neurotrophic factor (BDNF) plasma concentrations and the BDNF Val66Met nucleotide polymorphism (SNP) in heroin-dependent patients. The pretreatment expression levels of plasma BDNF and the BDNF Val66Met SNP in 172 heroin-dependent patients and 102 healthy controls were checked. BDNF levels were significantly lower in patients (F = 52.28, p BDNF levels significantly different between Met/Met, Met/Val, and Val/Val carriers in each group, which indicated that the BDNF Val66Met SNP did not affect plasma BDNF levels in our participants. In heroin-dependent patients, plasma BDNF levels were negatively correlated with the length of heroin dependency. Long-term (>15 years) users had significantly lower plasma BDNF levels than did short-term (BDNF concentration in habitual heroin users are not affected by BDNF Val66Met gene variants, but by the length of the heroin dependency.

  3. Transcriptional dynamics with time-dependent reaction rates

    Science.gov (United States)

    Nandi, Shubhendu; Ghosh, Anandamohan

    2015-02-01

    Transcription is the first step in the process of gene regulation that controls cell response to varying environmental conditions. Transcription is a stochastic process, involving synthesis and degradation of mRNAs, that can be modeled as a birth-death process. We consider a generic stochastic model, where the fluctuating environment is encoded in the time-dependent reaction rates. We obtain an exact analytical expression for the mRNA probability distribution and are able to analyze the response for arbitrary time-dependent protocols. Our analytical results and stochastic simulations confirm that the transcriptional machinery primarily act as a low-pass filter. We also show that depending on the system parameters, the mRNA levels in a cell population can show synchronous/asynchronous fluctuations and can deviate from Poisson statistics.

  4. Transcriptional dynamics with time-dependent reaction rates

    International Nuclear Information System (INIS)

    Nandi, Shubhendu; Ghosh, Anandamohan

    2015-01-01

    Transcription is the first step in the process of gene regulation that controls cell response to varying environmental conditions. Transcription is a stochastic process, involving synthesis and degradation of mRNAs, that can be modeled as a birth–death process. We consider a generic stochastic model, where the fluctuating environment is encoded in the time-dependent reaction rates. We obtain an exact analytical expression for the mRNA probability distribution and are able to analyze the response for arbitrary time-dependent protocols. Our analytical results and stochastic simulations confirm that the transcriptional machinery primarily act as a low-pass filter. We also show that depending on the system parameters, the mRNA levels in a cell population can show synchronous/asynchronous fluctuations and can deviate from Poisson statistics. (paper)

  5. Tolerable Time-Varying Overflow on Grass-Covered Slopes

    Directory of Open Access Journals (Sweden)

    Steven A. Hughes

    2015-03-01

    Full Text Available Engineers require estimates of tolerable overtopping limits for grass-covered levees, dikes, and embankments that might experience steady overflow. Realistic tolerance estimates can be used for both resilient design and risk assessment. A simple framework is developed for estimating tolerable overtopping on grass-covered slopes caused by slowly-varying (in time overtopping discharge (e.g., events like storm surges or river flood waves. The framework adapts the well-known Hewlett curves of tolerable limiting velocity as a function of overflow duration. It has been hypothesized that the form of the Hewlett curves suggests that the grass erosion process is governed by the flow work on the slope above a critical threshold velocity (referred to as excess work, and the tolerable erosional limit is reached when the cumulative excess work exceeds a given value determined from the time-dependent Hewlett curves. The cumulative excess work is expressed in terms of overflow discharge above a critical discharge that slowly varies in time, similar to a discharge hydrograph. The methodology is easily applied using forecast storm surge hydrographs at specific locations where wave action is minimal. For preliminary planning purposes, when storm surge hydrographs are unavailable, hypothetical equations for the water level and overflow discharge hydrographs are proposed in terms of the values at maximum overflow and the total duration of overflow. An example application is given to illustrate use of the methodology.

  6. Population-level impacts of pesticide-induced chronic effects on individuals depend more on ecology than toxicology

    DEFF Research Database (Denmark)

    Dalkvist, Trine; Topping, Christopher John; Forbes, Valery, E.

    2009-01-01

    at the population-level. Here we demonstrate how, using ABM modelling, assessments at the population-level can be obtained even for a pesticide with complex long-term effects such as epigenetic transmission of reproductive depression. By objectively fitting nonlinear models to the simulation outputs it was possible...... to compare population depression and recovery rates for a range of scenarios in which toxicity and exposure factors were varied. The system was differentially sensitive to the various factors, but vole ecology and behaviour were at least as important predictors of population-level effects as toxicology...

  7. Audiovisual speech perception development at varying levels of perceptual processing.

    Science.gov (United States)

    Lalonde, Kaylah; Holt, Rachael Frush

    2016-04-01

    This study used the auditory evaluation framework [Erber (1982). Auditory Training (Alexander Graham Bell Association, Washington, DC)] to characterize the influence of visual speech on audiovisual (AV) speech perception in adults and children at multiple levels of perceptual processing. Six- to eight-year-old children and adults completed auditory and AV speech perception tasks at three levels of perceptual processing (detection, discrimination, and recognition). The tasks differed in the level of perceptual processing required to complete them. Adults and children demonstrated visual speech influence at all levels of perceptual processing. Whereas children demonstrated the same visual speech influence at each level of perceptual processing, adults demonstrated greater visual speech influence on tasks requiring higher levels of perceptual processing. These results support previous research demonstrating multiple mechanisms of AV speech processing (general perceptual and speech-specific mechanisms) with independent maturational time courses. The results suggest that adults rely on both general perceptual mechanisms that apply to all levels of perceptual processing and speech-specific mechanisms that apply when making phonetic decisions and/or accessing the lexicon. Six- to eight-year-old children seem to rely only on general perceptual mechanisms across levels. As expected, developmental differences in AV benefit on this and other recognition tasks likely reflect immature speech-specific mechanisms and phonetic processing in children.

  8. Computing Conditional VaR using Time-varying CopulasComputing Conditional VaR using Time-varying Copulas

    Directory of Open Access Journals (Sweden)

    Beatriz Vaz de Melo Mendes

    2005-12-01

    Full Text Available It is now widespread the use of Value-at-Risk (VaR as a canonical measure at risk. Most accurate VaR measures make use of some volatility model such as GARCH-type models. However, the pattern of volatility dynamic of a portfolio follows from the (univariate behavior of the risk assets, as well as from the type and strength of the associations among them. Moreover, the dependence structure among the components may change conditionally t past observations. Some papers have attempted to model this characteristic by assuming a multivariate GARCH model, or by considering the conditional correlation coefficient, or by incorporating some possibility for switches in regimes. In this paper we address this problem using time-varying copulas. Our modeling strategy allows for the margins to follow some FIGARCH type model while the copula dependence structure changes over time.

  9. Relations between vegetation and water level in groundwater dependent terrestrial ecosystems (GWDTEs)

    DEFF Research Database (Denmark)

    Munch Johansen, Ole; Andersen, Dagmar Kappel; Ejrnæs, Rasmus

    2018-01-01

    , management and conservation of fens are constrained by limited knowledge on the relations between vegetation and measurable hydrological conditions. This study investigates the relations between vegetation and water level dynamics in groundwater dependent wetlands in Denmark. A total of 35 wetland sites...... across Denmark were included in the study. The sites represent a continuum of wetlands with respect to vegetation and hydrological conditions. Water level was measured continuously using pressure transducers at each site. Metrics expressing different hydrological characteristics, such as mean water level...... and low and high water level periods, were calculated based on the water level time series. A complete plant species list was recorded in plots covering 78.5 m2 at each site. Community metrics such as total number of species and the number of bryophytes were generated from the species lists and Ellenberg...

  10. Temperature dependence of electroluminescent emission from (ZnS : Cu, Mn(H)) type luminophors

    International Nuclear Information System (INIS)

    Singh, L.K.

    1986-04-01

    The dependence of electroluminescent yield on temperature for hydrogen coactivated (ZnS : Cu, Mn) type triple band emitting phosphors has been investigated at various temperatures under varied operating conditions of excitations. The influence of the excitation frequency, voltage and of emission wavelengths for the electroluminescent characteristics has also been observed on temperature variations. The results have also been studied for temperature dependences of emitting brightness under the excitation by UV-radiations of 3650 A.U. and a comparison is made between temperature dependent characteristics of E.L. and PL-brightness of emissions. It was observed that, as usual, brightness maxima on temperature scale varied with alteration of operating electric fields regarding frequency and voltage both for blue, green and yellow orange emissions of attempted samples. The important thing which is observed here, is that with regards the temperature EL-intensities vary respectively for all respective emissions but emission peaks are not shifted on wave-length scale. This no shift is due to the narrowly and compactly distributed coactivator levels of hydrogen. (author)

  11. Varying hemin concentrations affect Porphyromonas gingivalis strains differently.

    Science.gov (United States)

    Ohya, Manabu; Cueno, Marni E; Tamura, Muneaki; Ochiai, Kuniyasu

    2016-05-01

    Porphyromonas gingivalis requires heme to grow, however, heme availability and concentration in the periodontal pockets vary. Fluctuations in heme concentration may affect each P. gingivalis strain differently, however, this was never fully demonstrated. Here, we elucidated the effects of varying hemin concentrations in representative P. gingivalis strains. Throughout this study, representative P. gingivalis strains [FDC381 (type I), MPWIb-01 (type Ib), TDC60 (type II), ATCC49417 (type III), W83 (type IV), and HNA99 (type V)] were used and grown for 24 h in growth media under varying hemin concentrations (5 × , 1 × , 0.5 × , 0.1 × ). Samples were lysed and protein standardized. Arg-gingipain (Rgp), H2O2, and superoxide dismutase (SOD) levels were subsequently measured. We focused our study on 24 h-grown strains which excluded MPWIb-01 and HNA99. Rgp activity among the 4 remaining strains varied with Rgp peaking at: 1 × for FDC381, 5 × for TDC60, 0.5 × for ATCC49417, 5 × and 0.5 × for W83. With regards to H2O2 and SOD amounts: FDC381 had similar H2O2 amounts in all hemin concentrations while SOD levels varied; TDC60 had the lowest H2O2 amount at 1 × while SOD levels became higher in relation to hemin concentration; ATCC49417 also had similar H2O2 amounts in all hemin concentrations while SOD levels were higher at 1 × and 0.5 × ; and W83 had statistically similar H2O2 and SOD amounts regardless of hemin concentration. Our results show that variations in hemin concentration affect each P. gingivalis strain differently. Published by Elsevier Ltd.

  12. Neurophysiological model of tinnitus: dependence of the minimal masking level on treatment outcome.

    Science.gov (United States)

    Jastreboff, P J; Hazell, J W; Graham, R L

    1994-11-01

    Validity of the neurophysiological model of tinnitus (Jastreboff, 1990), outlined in this paper, was tested on data from multicenter trial of tinnitus masking (Hazell et al., 1985). Minimal masking level, intensity match of tinnitus, and the threshold of hearing have been evaluated on a total of 382 patients before and after 6 months of treatment with maskers, hearing aids, or combination devices. The data has been divided into categories depending on treatment outcome and type of approach used. Results of analysis revealed that: i) the psychoacoustical description of tinnitus does not possess a predictive value for the outcome of the treatment; ii) minimal masking level changed significantly depending on the treatment outcome, decreasing on average by 5.3 dB in patients reporting improvement, and increasing by 4.9 dB in those whose tinnitus remained the same or worsened; iii) 73.9% of patients reporting improvement had their minimal masking level decreased as compared with 50.5% for patients not showing improvement, which is at the level of random change; iv) the type of device used has no significant impact on the treatment outcome and minimal masking level change; v) intensity match and threshold of hearing did not exhibit any significant changes which can be related to treatment outcome. These results are fully consistent with the neurophysiological interpretation of mechanisms involved in the phenomenon of tinnitus and its alleviation.

  13. Exponential Antisynchronization Control of Stochastic Memristive Neural Networks with Mixed Time-Varying Delays Based on Novel Delay-Dependent or Delay-Independent Adaptive Controller

    Directory of Open Access Journals (Sweden)

    Minghui Yu

    2017-01-01

    Full Text Available The global exponential antisynchronization in mean square of memristive neural networks with stochastic perturbation and mixed time-varying delays is studied in this paper. Then, two kinds of novel delay-dependent and delay-independent adaptive controllers are designed. With the ability of adapting to environment changes, the proposed controllers can modify their behaviors to achieve the best performance. In particular, on the basis of the differential inclusions theory, inequality theory, and stochastic analysis techniques, several sufficient conditions are obtained to guarantee the exponential antisynchronization between the drive system and response system. Furthermore, two numerical simulation examples are provided to the validity of the derived criteria.

  14. Oxidative stability and ignition quality of algae derived methyl esters containing varying levels of methyl eicosapentaenoate and methyl docosahexaenoate

    Science.gov (United States)

    Bucy, Harrison

    Microalgae is currently receiving strong consideration as a potential biofuel feedstock to help meet the advanced biofuels mandate of the 2007 Energy Independence and Security Act because of its theoretically high yield (gallons/acre/year) in comparison to current terrestrial feedstocks. Additionally, microalgae also do not compete with food and can be cultivated with wastewater on non-arable land. Microalgae lipids can be converted into a variety of biofuels including fatty acid methyl esters (e.g. FAME biodiesel), renewable diesel, renewable gasoline, or jet fuel. For microalgae derived FAME, the fuel properties will be directly related to the fatty acid composition of the lipids produced by the given microalgae strain. Several microalgae species under consideration for wide scale cultivation, such as Nannochloropsis, produce lipids with fatty acid compositions containing substantially higher quantities of long chainpolyunsaturated fatty acids (LC-PUFA) in comparison to terrestrial feedstocks. It is expected that increased levels of LC-PUFA will be problematic in terms of meeting all of the current ASTM specifications for biodiesel. For example, it is known that oxidative stability and cetane number decrease with increasing levels of LC-PUFA. However, these same LC-PUFA fatty acids, such as eicosapentaenoic acid (EPA: C20:5) and docosahexaenoic acid (DHA: C22:6) are known to have high nutritional value thereby making separation of these compounds economically attractive. Given the uncertainty in the future value of these LC-PUFA compounds and the economic viability of the separation process, the goal of this study was to examine the oxidative stability and ignition quality of algae-based FAME with varying levels of EPA and DHA removal. Oxidative stability tests were conducted at a temperature of 110°C and airflow of 10 L/h using a Metrohm 743 Rancimat with automatic induction period determination following the EN 14112 Method from the ASTM D6751 and EN 14214

  15. Subgap time of flight: A spectroscopic study of deep levels in semi-insulating CdTe:Cl

    Energy Technology Data Exchange (ETDEWEB)

    Pousset, J.; Farella, I.; Cola, A., E-mail: adriano.cola@le.imm.cnr.it [Institute for Microelectronics and Microsystems—Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Gambino, S. [Dipartimento di Matematica e Fisica “Ennio De Giorgi,” Università del Salento, Lecce I-73100 (Italy); CNR NANOTEC—Istituto di Nanotecnologia, Polo di Nanotecnologia c/o Campus Ecotekne, via Monteroni, 73100 Lecce (Italy)

    2016-03-14

    We report on a study of deep levels in semi-insulating CdTe:Cl by means of a time-of-flight spectral approach. By varying the wavelength of a pulsed optical source within the CdTe energy gap, transitions to/from localized levels generate free carriers which are analysed through the induced photocurrent transients. Both acceptor-like centers, related to the A-center, and a midgap level, 0.725 eV from the valence band, have been detected. The midgap level is close to the Fermi level and is possibly a recombination center responsible for the compensation mechanism. When the irradiance is varied, either linear or quadratic dependence of the electron and hole collected charge are observed, depending on the dominant optical transitions. The analysis discloses the potentiality of such a novel approach exploitable in the field of photorefractive materials as well as for deep levels spectroscopy.

  16. Subgap time of flight: A spectroscopic study of deep levels in semi-insulating CdTe:Cl

    International Nuclear Information System (INIS)

    Pousset, J.; Farella, I.; Cola, A.; Gambino, S.

    2016-01-01

    We report on a study of deep levels in semi-insulating CdTe:Cl by means of a time-of-flight spectral approach. By varying the wavelength of a pulsed optical source within the CdTe energy gap, transitions to/from localized levels generate free carriers which are analysed through the induced photocurrent transients. Both acceptor-like centers, related to the A-center, and a midgap level, 0.725 eV from the valence band, have been detected. The midgap level is close to the Fermi level and is possibly a recombination center responsible for the compensation mechanism. When the irradiance is varied, either linear or quadratic dependence of the electron and hole collected charge are observed, depending on the dominant optical transitions. The analysis discloses the potentiality of such a novel approach exploitable in the field of photorefractive materials as well as for deep levels spectroscopy.

  17. Computed tomography imaging with the Adaptive Statistical Iterative Reconstruction (ASIR) algorithm: dependence of image quality on the blending level of reconstruction.

    Science.gov (United States)

    Barca, Patrizio; Giannelli, Marco; Fantacci, Maria Evelina; Caramella, Davide

    2018-06-01

    Computed tomography (CT) is a useful and widely employed imaging technique, which represents the largest source of population exposure to ionizing radiation in industrialized countries. Adaptive Statistical Iterative Reconstruction (ASIR) is an iterative reconstruction algorithm with the potential to allow reduction of radiation exposure while preserving diagnostic information. The aim of this phantom study was to assess the performance of ASIR, in terms of a number of image quality indices, when different reconstruction blending levels are employed. CT images of the Catphan-504 phantom were reconstructed using conventional filtered back-projection (FBP) and ASIR with reconstruction blending levels of 20, 40, 60, 80, and 100%. Noise, noise power spectrum (NPS), contrast-to-noise ratio (CNR) and modulation transfer function (MTF) were estimated for different scanning parameters and contrast objects. Noise decreased and CNR increased non-linearly up to 50 and 100%, respectively, with increasing blending level of reconstruction. Also, ASIR has proven to modify the NPS curve shape. The MTF of ASIR reconstructed images depended on tube load/contrast and decreased with increasing blending level of reconstruction. In particular, for low radiation exposure and low contrast acquisitions, ASIR showed lower performance than FBP, in terms of spatial resolution for all blending levels of reconstruction. CT image quality varies substantially with the blending level of reconstruction. ASIR has the potential to reduce noise whilst maintaining diagnostic information in low radiation exposure CT imaging. Given the opposite variation of CNR and spatial resolution with the blending level of reconstruction, it is recommended to use an optimal value of this parameter for each specific clinical application.

  18. DIFFERENCES REGARDING SELF-ESTEEM AND THE COMMUNICATION STYLE DEPENDING ON THE LEVEL OF EDUCATION

    Directory of Open Access Journals (Sweden)

    Georgeta PÂNIȘOARĂ

    2015-12-01

    Full Text Available The present paper aims to study the differences in self-esteem and the communication style, depending on the level of education (at high school and university subjects. It is analyzed also how the positive self-esteem can correlate with a style of communication and assertively-positive approach. The participants are 120 subjects, 60 high school students and 60 students. The data was collected using two instruments: the Rosenberg questionnaire and a questionnaire on communication style. The data analyzed using a t test for independent samples and a Pearson correlation test with SPSS statistical software. The results show that there are differences regarding the self-esteem and the communication style depending on the level of education.

  19. Continuum corrections to the level density and its dependence on excitation energy, n-p asymmetry, and deformation

    International Nuclear Information System (INIS)

    Charity, R.J.; Sobotka, L.G.

    2005-01-01

    In the independent-particle model, the nuclear level density is determined from the neutron and proton single-particle level densities. The single-particle level density for the positive-energy continuum levels is important at high excitation energies for stable nuclei and at all excitation energies for nuclei near the drip lines. This single-particle level density is subdivided into compound-nucleus and gas components. Two methods are considered for this subdivision: In the subtraction method, the single-particle level density is determined from the scattering phase shifts. In the Gamov method, only the narrow Gamov states or resonances are included. The level densities calculated with these two methods are similar; both can be approximated by the backshifted Fermi-gas expression with level-density parameters that are dependent on A, but with very little dependence on the neutron or proton richness of the nucleus. However, a small decrease in the level-density parameter is predicted for some nuclei very close to the drip lines. The largest difference between the calculations using the two methods is the deformation dependence of the level density. The Gamov method predicts a very strong peaking of the level density at sphericity for high excitation energies. This leads to a suppression of deformed configurations and, consequently, the fission rate predicted by the statistical model is reduced in the Gamov method

  20. Effect of varying levels of zinc and manganese of drymatter yield and mineral composition of wheat plant at maturity

    International Nuclear Information System (INIS)

    Sachdev, P.; Deb, D.L.

    1988-01-01

    The fertilizer zinc uptake by wheat increased with increasing zinc levels but the percentage utilisation was much lower with 10 kg Zn ha -1 application (0.65 per cent) as compared to 5 kg Zn ha -1 (1.22 per cent). The zinc derived from fertilizer was significantly affected by the levels of zinc application only in wheat straw and not in grain. The application of varying levels of manganese did not affect the per cent Zndff and fertilizer zinc uptake by wheat. The wheat crop required only 405 g of zinc per hectare with a harvest of 4.7 tonnes of grains and 6.4 tonnes of straw but under zinc deficient soil conditions even this amount could not be met and consequently zinc deficiency resulted in low drymatter production . Only about 66 g of the applied zinc was utilised by the crop but it gave an extra yield of 3.2 q ha -1 of grain and 9.8 q ha -1 of straw compared to that obtained with no zinc application. Application of manganese did not affect the total drymatter yield and straw yield, but grain yield showed significant depression at 20 kg ha -1 level as compared to 10 kg Mn ha -1 level. (author). 6 tabs., 9 refs

  1. Population-Level Density Dependence Influences the Origin and Maintenance of Parental Care.

    Science.gov (United States)

    Reyes, Elijah; Thrasher, Patsy; Bonsall, Michael B; Klug, Hope

    2016-01-01

    Parental care is a defining feature of animal breeding systems. We now know that both basic life-history characteristics and ecological factors influence the evolution of care. However, relatively little is known about how these factors interact to influence the origin and maintenance of care. Here, we expand upon previous work and explore the relationship between basic life-history characteristics (stage-specific rates of mortality and maturation) and the fitness benefits associated with the origin and the maintenance of parental care for two broad ecological scenarios: the scenario in which egg survival is density dependent and the case in which adult survival is density dependent. Our findings suggest that high offspring need is likely critical in driving the origin, but not the maintenance, of parental care regardless of whether density dependence acts on egg or adult survival. In general, parental care is more likely to result in greater fitness benefits when baseline adult mortality is low if 1) egg survival is density dependent or 2) adult mortality is density dependent and mutant density is relatively high. When density dependence acts on egg mortality, low rates of egg maturation and high egg densities are less likely to lead to strong fitness benefits of care. However, when density dependence acts on adult mortality, high levels of egg maturation and increasing adult densities are less likely to maintain care. Juvenile survival has relatively little, if any, effect on the origin and maintenance of egg-only care. More generally, our results suggest that the evolution of parental care will be influenced by an organism's entire life history characteristics, the stage at which density dependence acts, and whether care is originating or being maintained.

  2. An MHD simulation model of time-dependent global solar corona with temporally varying solar-surface magnetic field maps

    Science.gov (United States)

    Hayashi, K.

    2013-11-01

    We present a model of a time-dependent three-dimensional magnetohydrodynamics simulation of the sub-Alfvenic solar corona and super-Alfvenic solar wind with temporally varying solar-surface boundary magnetic field data. To (i) accommodate observational data with a somewhat arbitrarily evolving solar photospheric magnetic field as the boundary value and (ii) keep the divergence-free condition, we developed a boundary model, here named Confined Differential Potential Field model, that calculates the horizontal components of the magnetic field, from changes in the vertical component, as a potential field confined in a thin shell. The projected normal characteristic method robustly simulates the solar corona and solar wind, in response to the temporal variation of the boundary Br. We conduct test MHD simulations for two periods, from Carrington Rotation number 2009 to 2010 and from Carrington Rotation 2074 to 2075 at solar maximum and minimum of Cycle 23, respectively. We obtained several coronal features that a fixed boundary condition cannot yield, such as twisted magnetic field lines at the lower corona and the transition from an open-field coronal hole to a closed-field streamer. We also obtained slight improvements of the interplanetary magnetic field, including the latitudinal component, at Earth.

  3. Varying Levels of Automation on UAS Operator Responses to Traffic Resolution Advisories in Civil Airspace

    Science.gov (United States)

    Kenny, Caitlin; Fern, Lisa

    2012-01-01

    Continuing demand for the use of Unmanned Aircraft Systems (UAS) has put increasing pressure on operations in civil airspace. The need to fly UAS in the National Airspace System (NAS) in order to perform missions vital to national security and defense, emergency management, and science is increasing at a rapid pace. In order to ensure safe operations in the NAS, operators of unmanned aircraft, like those of manned aircraft, may be required to maintain separation assurance and avoid loss of separation with other aircraft while performing their mission tasks. This experiment investigated the effects of varying levels of automation on UAS operator performance and workload while responding to conflict resolution instructions provided by the Tactical Collision Avoidance System II (TCAS II) during a UAS mission in high-density airspace. The purpose of this study was not to investigate the safety of using TCAS II on UAS, but rather to examine the effect of automation on the ability of operators to respond to traffic collision alerts. Six licensed pilots were recruited to act as UAS operators for this study. Operators were instructed to follow a specified mission flight path, while maintaining radio contact with Air Traffic Control and responding to TCAS II resolution advisories. Operators flew four, 45 minute, experimental missions with four different levels of automation: Manual, Knobs, Management by Exception, and Fully Automated. All missions included TCAS II Resolution Advisories (RAs) that required operator attention and rerouting. Operator compliance and reaction time to RAs was measured, and post-run NASA-TLX ratings were collected to measure workload. Results showed significantly higher compliance rates, faster responses to TCAS II alerts, as well as less preemptive operator actions when higher levels of automation are implemented. Physical and Temporal ratings of workload were significantly higher in the Manual condition than in the Management by Exception and

  4. Order Level Inventory Models for Deteriorating Seasonable/Fashionable Products with Time Dependent Demand and Shortages

    Directory of Open Access Journals (Sweden)

    K. Skouri

    2009-01-01

    Full Text Available An order level inventory model for seasonable/fashionable products subject to a period of increasing demand followed by a period of level demand and then by a period of decreasing demand rate (three branches ramp type demand rate is considered. The unsatisfied demand is partially backlogged with a time dependent backlogging rate. In addition, the product deteriorates with a time dependent, namely, Weibull, deterioration rate. The model is studied under the following different replenishment policies: (a starting with no shortages and (b starting with shortages. The optimal replenishment policy for the model is derived for both the above mentioned policies.

  5. Intake of Seafood in the US Varies by Age, Income, and Education Level but Not by Race-Ethnicity

    Directory of Open Access Journals (Sweden)

    Lisa Jahns

    2014-12-01

    Full Text Available Current US federal dietary guidance recommends regular consumption of seafood (fish + shellfish to promote health; however, little is known about how well Americans meet the guideline, particularly population subgroups that may be at risk for inadequate intake. The purposes of this study were to describe the prevalence of seafood consumption and, among consumers, the amounts of seafood eaten by sex, age group, income and education level, and race-ethnicity. Data from 15,407 adults aged 19+ participating in the 2005–2010 National Health and Nutrition Examination Surveys were analyzed using methods to account for sporadic intake of seafood. Over 80% of Americans reported consuming any seafood over the past 30 days, 74% reported consuming fish, and 54% reported eating shellfish. The percentages varied by socio-demographic group. Younger age and lower income and education levels were associated with lower odds of being a seafood consumer (p < 0.0001. Among those who reported eating seafood, the average amount eaten of any seafood was 158.2 ± 5.6 g/week. Among seafood consumers, women and individuals of lower age and education levels consumed less seafood. Approximately 80%–90% of seafood consumers did not meet seafood recommendations when needs were estimated by energy requirements. A great deal of work remains to move Americans toward seafood consumption at current recommended levels.

  6. Reducing the substrate dependent scanner leveling effect in low-k1 contact printing

    Science.gov (United States)

    Chang, C. S.; Tseng, C. F.; Huang, C. H.; Yang, Elvis; Yang, T. H.; Chen, K. C.

    2015-03-01

    As the scaling down of design rule for high-density memory device, the small depth of focus (DoF) budget may be deteriorated by focus leveling errors, which arises in unpredicted reflectivity from multilayer structures on the topographic wafer. The leveling sensors of ASML scanner use near infrared (NIR) range wavelength which can penetrate through most of films using in semiconductor fabrication such as photo-resist, bottom anti reflective coating (BARC) and dielectric materials. Consequently, the reflected light from underlying substructures would disturb leveling sensors from accurate leveling. The different pattern densities and layout characteristics between array and periphery of a memory chip are expected to result in different leveling signals. Furthermore, the process dependent variations between wafer central and edge areas are also considered to yield different leveling performances during wafer exposure. In this study, lower blind contact immunity was observed for peripheral contacts comparing to the array contacts especially around wafer edge region. In order to overcome this problem, a series of investigations have been carried out. The wafer edge leveling optimization through circuit dependent focus edge clearance (CDFEC) option doesn't get improvement. Air gauge improved process leveling (AGILE) function of ASML immersion scanner doesn't show improved result either. The ILD uniformity improvement and step height treatments around wafer edge such as edge exclusion of film deposition and bevel etching are also ineffective to mitigate the blind contact problem of peripheral patterns. Altering the etch hard-mask stack is finally found to be an effective approach to alleviate the issue. For instance, through either containing high temperature deposition advanced patterning film (APF) in the hard-mask or inserting higher opaque film such as amorphous Si in between the hard-mask stack.

  7. Frequency dependent changes in NMDAR-dependent synaptic plasticity

    Directory of Open Access Journals (Sweden)

    Arvind eKumar

    2011-09-01

    Full Text Available The NMDAR-dependent synaptic plasticity is thought to mediate several forms of learning, and can be induced by spike trains containing a small number of spikes occurring with varying rates and timing, as well as with oscillations. We computed the influence of these variables on the plasticity induced at a single NMDAR containing synapse using a reduced model that was analytically tractable, and these findings were confirmed using detailed, multi-compartment model. In addition to explaining diverse experimental results about the rate and timing dependence of synaptic plasticity, the model made several novel and testable predictions. We found that there was a preferred frequency for inducing long-term potentiation (LTP such that higher frequency stimuli induced lesser LTP, decreasing as 1/f when the number of spikes in the stimulus was kept fixed. Among other things, the preferred frequency for inducing LTP varied as a function of the distance of the synapse from the soma. In fact, same stimulation frequencies could induce LTP or LTD depending on the dendritic location of the synapse. Next, we found that rhythmic stimuli induced greater plasticity then irregular stimuli. Furthermore, brief bursts of spikes significantly expanded the timing dependence of plasticity. Finally, we found that in the ~5-15Hz frequency range both rate- and timing-dependent plasticity mechanisms work synergistically to render the synaptic plasticity most sensitive to spike-timing. These findings provide computational evidence that oscillations can have a profound influence on the plasticity of an NMDAR-dependent synapse, and show a novel role for the dendritic morphology in this process.

  8. Panel Data with Cross-Sectional Dependence Characterized by a Multi-Level Factor Structure

    DEFF Research Database (Denmark)

    Rodríguez-Caballero, Carlos Vladimir

    A panel data model with a multi-level cross-sectional dependence is proposed. The factor structure is driven by top-level common factors as well as non-pervasive factors. I propose a simple method to filter out the full factor structure that overcomes limitations in standard procedures which may...... mix up both levels of unobservable factors and may hamper the identification of the model. The model covers both stationary and non-stationary cases and takes into account other relevant features that make the model well suited to the analysis of many types of time series frequently addressed...

  9. Linear response approach to active Brownian particles in time-varying activity fields

    Science.gov (United States)

    Merlitz, Holger; Vuijk, Hidde D.; Brader, Joseph; Sharma, Abhinav; Sommer, Jens-Uwe

    2018-05-01

    In a theoretical and simulation study, active Brownian particles (ABPs) in three-dimensional bulk systems are exposed to time-varying sinusoidal activity waves that are running through the system. A linear response (Green-Kubo) formalism is applied to derive fully analytical expressions for the torque-free polarization profiles of non-interacting particles. The activity waves induce fluxes that strongly depend on the particle size and may be employed to de-mix mixtures of ABPs or to drive the particles into selected areas of the system. Three-dimensional Langevin dynamics simulations are carried out to verify the accuracy of the linear response formalism, which is shown to work best when the particles are small (i.e., highly Brownian) or operating at low activity levels.

  10. Population-Level Density Dependence Influences the Origin and Maintenance of Parental Care.

    Directory of Open Access Journals (Sweden)

    Elijah Reyes

    Full Text Available Parental care is a defining feature of animal breeding systems. We now know that both basic life-history characteristics and ecological factors influence the evolution of care. However, relatively little is known about how these factors interact to influence the origin and maintenance of care. Here, we expand upon previous work and explore the relationship between basic life-history characteristics (stage-specific rates of mortality and maturation and the fitness benefits associated with the origin and the maintenance of parental care for two broad ecological scenarios: the scenario in which egg survival is density dependent and the case in which adult survival is density dependent. Our findings suggest that high offspring need is likely critical in driving the origin, but not the maintenance, of parental care regardless of whether density dependence acts on egg or adult survival. In general, parental care is more likely to result in greater fitness benefits when baseline adult mortality is low if 1 egg survival is density dependent or 2 adult mortality is density dependent and mutant density is relatively high. When density dependence acts on egg mortality, low rates of egg maturation and high egg densities are less likely to lead to strong fitness benefits of care. However, when density dependence acts on adult mortality, high levels of egg maturation and increasing adult densities are less likely to maintain care. Juvenile survival has relatively little, if any, effect on the origin and maintenance of egg-only care. More generally, our results suggest that the evolution of parental care will be influenced by an organism's entire life history characteristics, the stage at which density dependence acts, and whether care is originating or being maintained.

  11. Dependence of spectrum on period and twist effect of the pulsars magnetic field

    International Nuclear Information System (INIS)

    Shitov, Yu.P.

    1983-01-01

    The analysis of flux depsities at 102, 408 and 2700 MHz shows that the mean spectral radio luminosity of pUlsars anti Lsub(ν) depends on their period P. The radio luminosity on the average, decreases with the increasing period at all three freqUercies. The character and power of the period dependence anti Lsub(ν)(P) are different at different freqUencies caUsing the corresponding period dependence of the mean radio spectrUm and, particularly, of the spectral index anti αsub(1-4)(102-408 MHz), anti αsub(1-4)(P) varies as Psup(1.7) for P 408 (P) varies as Psup(-1.3) in the period interval 0.3 408 and the period derivatives P, between αsub(1-4) and P. In this connection, the arthor draws the conclusion that period dependences of the spectral radio luminosity and of the spectrum of pulsars are caused by geometrical factors. Quantitative estimates show that the twist effect of magnetic field lines caused by the reaction of magnetic-dipole radiation may be such a geometrical factor, which increases the field line curvatUre (as compared to the dipole field). The twist curvature rhosub(rot)sup(-1) varies as PsUp(-3)xrsup(2) (r is the radial distance from a star) causes the observed period dependence anti Lsub(ν)(P) owing to the curvature emission mechanism. The twist effect of the magnetic field gives the possibility to estimate height levels r of the radio emission regions in a pulsar from the observed function anti Lsub(π)(P). At 408 MHz for an ''average statistic'' pulsar with P> or approximately 0.3 s the level r 408 =1x10 9 cm

  12. N-Acetylcysteine Normalizes Glutamate Levels in Cocaine-Dependent Patients: A Randomized Crossover Magnetic Resonance Spectroscopy Study

    NARCIS (Netherlands)

    Schmaal, Lianne; Veltman, Dick J.; Nederveen, Aart; van den Brink, Wim; Goudriaan, Anna E.

    2012-01-01

    Treatment with N-acetylcysteine (NAC) normalizes glutamate (Glu) homeostasis and prevents relapse in drug-dependent animals. However, the effect of NAC on brain Glu levels in substance-dependent humans has not yet been investigated. Proton magnetic resonance spectroscopy (H-1 MRS) was used to

  13. N-Acetylcysteine Normalizes Glutamate Levels in Cocaine-Dependent Patients: A Randomized Crossover Magnetic Resonance Spectroscopy Study

    NARCIS (Netherlands)

    Schmaal, L.; Veltman, D.J.; Nederveen, A.; van den Brink, W.; Goudriaan, A.E.

    2012-01-01

    Treatment with N-acetylcysteine (NAC) normalizes glutamate (Glu) homeostasis and prevents relapse in drug-dependent animals. However, the effect of NAC on brain Glu levels in substance-dependent humans has not yet been investigated. Proton magnetic resonance spectroscopy (1 H MRS) was used to

  14. Pulsed low-level infrared laser alters mRNA levels from muscle repair genes dependent on power output in Wistar rats

    Science.gov (United States)

    Trajano, L. A. S. N.; Trajano, E. T. L.; Thomé, A. M. C.; Sergio, L. P. S.; Mencalha, A. L.; Stumbo, A. C.; Fonseca, A. S.

    2017-10-01

    Satellite cells are present in skeletal muscle functioning in the repair and regeneration of muscle injury. Activation of these cells depends on the expression of myogenic factor 5 (Myf5), myogenic determination factor 1(MyoD), myogenic regulatory factor 4 (MRF4), myogenin (MyoG), paired box transcription factors 3 (Pax3), and 7 (Pax7). Low-level laser irradiation accelerates the repair of muscle injuries. However, data from the expression of myogenic factors have been controversial. Furthermore, the effects of different laser beam powers on the repair of muscle injuries have been not evaluated. The aim of this study was to evaluate the effects of low-level infrared laser at different powers and in pulsed emission mode on the expression of myogenic regulatory factors and on Pax3 and Pax7 in injured skeletal muscle from Wistar rats. Animals that underwent cryoinjury were divided into three groups: injury, injury laser 25 Mw, and injury laser 75 mW. Low-level infrared laser irradiation (904 nm, 3 J cm-2, 5 kHz) was carried out at 25 and 75 mW. After euthanasia, skeletal muscle samples were withdrawn and the total RNA was extracted for the evaluation of mRNA levels from the MyoD, MyoG, MRF4, Myf5, Pax3, and Pax7 gene. Pax 7 mRNA levels did not alter, but Pax3 mRNA levels increased in the injured and laser-irradiated group at 25 mW. MyoD, MyoG, and MYf5 mRNA levels increased in the injured and laser-irradiated animals at both powers, and MRF4 mRNA levels decreased in the injured and laser-irradiated group at 75 mW. In conclusion, exposure to pulsed low-level infrared laser, by power-dependent effect, could accelerate the muscle repair process altering mRNA levels from paired box transcription factors and myogenic regulatory factors.

  15. Aspects of two-level systems under external time-dependent fields

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V.G.; Wreszinski, W.F. [Tomsk State University and Tomsk Institute of High Current Electronics (Russian Federation); Barata, J.C.A.; Gitman D.M. [Universidade de Sao Paulo, Instituto de Fisica (Brazil)]. E-mails: jbarata@fma.if.usp.br; gitman@fma.if.usp.br

    2001-12-14

    The dynamics of two-level systems in time-dependent backgrounds is under consideration. We present some new exact solutions in special backgrounds decaying in time. On the other hand, following ideas of Feynman et al, we discuss in detail the possibility of reducing the quantum dynamics to a classical Hamiltonian system. This, in particular, opens the possibility of directly applying powerful methods of classical mechanics (e.g. KAM methods) to study the quantum system. Following such an approach, we draw conclusions of relevance for 'quantum chaos' when the external background is periodic or quasi-periodic in time. (author)

  16. Pollinator-mediated interactions in experimental arrays vary with neighbor identity.

    Science.gov (United States)

    Ha, Melissa K; Ivey, Christopher T

    2017-02-01

    Local ecological conditions influence the impact of species interactions on evolution and community structure. We investigated whether pollinator-mediated interactions between coflowering plants vary with plant density, coflowering neighbor identity, and flowering season. We conducted a field experiment in which flowering time and floral neighborhood were manipulated in a factorial design. Early- and late-flowering Clarkia unguiculata plants were placed into arrays with C. biloba neighbors, noncongeneric neighbors, additional conspecific plants, or no additional plants as a density control. We compared whole-plant pollen limitation of seed set, pollinator behavior, and pollen deposition among treatments. Interactions mediated by shared pollinators depended on the identity of the neighbor and possibly changed through time, although flowering-season comparisons were compromised by low early-season plant survival. Interactions with conspecific neighbors were likely competitive late in the season. Interactions with C. biloba appeared to involve facilitation or neutral interactions. Interactions with noncongeners were more consistently competitive. The community composition of pollinators varied among treatment combinations. Pollinator-mediated interactions involved competition and likely facilitation, depending on coflowering neighbor. Experimental manipulation helped to reveal context-dependent variation in indirect biotic interactions. © 2017 Botanical Society of America.

  17. 股指期货对现货时变相依结构的多尺度研究%Multi-scale Study on Time-varying Dependency Structure between the Stock Index Futures and the Actual

    Institute of Scientific and Technical Information of China (English)

    彭选华; 傅强

    2011-01-01

    Copula theory is very popular to model the dependency structure between the price of future and spot market in financial analysis including risk hedge,hedging portfolio and price discovery.This paper considers the innovation asymmetric impact on the price and the time-varying characteristics of the dependency structure,and constructs a time-varying T-Copula-GJR-GARCH model by using a GJR-GARCH model to fit the two returns,respectively.By choosing the DCC equation to depict the dynamic structure of the time-varying coefficient,and based on high frequency price data from 5 to 60 minute of the Hu-Shen 300 index futures and stock market,we establish a time-varying T-Copula-GJR-GARCH(1,1)-T model by time-scale.The results indicate the dependent structure changes over time-scale,which may be explained by the market microstructure and heterogeneity of the investors.Hence,this paper reveals the potential time-varying dependency patterns between China's stock index futures and spot market at multi-scale time horizons.%股指期货与现货之间的相依结构是Copula理论在金融分析中套期保值、组合风险对冲及价格发现等应用的热点。考虑到新息对价格的非对称冲击和相依结构的时变特征,利用GJR-GARCH模型对股指期货和现货的收益率序列建模,选用DCC方程刻画二者之间时变相关系数的演化结构,构建时变T-Copula-GJR-GARCH模型。针对沪深300指数现货与期货5~60分钟的高频数据,分尺度拟合时变T-Copula-GJR-GARCH(1,1)-t模型,结果表明相依结构随时间尺度变化而变化,这或许可由市场微观结构差异及投资者的

  18. Vitamin D Status in Population of Bukovyna and Subcarpathia Depending on Residence above Sea Level

    Directory of Open Access Journals (Sweden)

    V.V. Povoroznyuk

    2016-04-01

    ding on the residence above sea level. Objective: to determine the level of vitamin D in the blood serum of people, who live in different regions of the Subcarpathia and Bukovyna, depending on the location of the settlement above sea le-vel. Material and methods. In the cross-sectional study, we have examined 353 individuals, aged 18 to 86 years, permanently residing in different parts of the Subcarpathia (Kolomyia, Kosiv, Verhovyna districts and Bukovyna (Vyzhny-tsia district. Results. Only in 28 cases (7.9 %, the content of 25(OHD in the blood serum was in the normal range, and in other cases (92.1 %, there was a deficiency and a lack of vitamin D. The severe form of vitamin D deficiency has been detected in 7 (1.9 % patients. When comparing the performance of 25(OHD in the areas of inspection, it was found that the level of vitamin D in the blood serum was significantly higher in residents of Verkhovyna and Kosiv districts (located higher than 450 meters above sea level as compared with residents of Vyzhnytsia and Kolomyia. Conclusion. The average level of vitamin D in the blood serum of the adult population depends on residence and increases with height above sea level.

  19. The Not-So-Global Blood Oxygen Level-Dependent Signal.

    Science.gov (United States)

    Billings, Jacob; Keilholz, Shella

    2018-04-01

    Global signal regression is a controversial processing step for resting-state functional magnetic resonance imaging, partly because the source of the global blood oxygen level-dependent (BOLD) signal remains unclear. On the one hand, nuisance factors such as motion can readily introduce coherent BOLD changes across the whole brain. On the other hand, the global signal has been linked to neural activity and vigilance levels, suggesting that it contains important neurophysiological information and should not be discarded. Any widespread pattern of coordinated activity is likely to contribute appreciably to the global signal. Such patterns may include large-scale quasiperiodic spatiotemporal patterns, known also to be tied to performance on vigilance tasks. This uncertainty surrounding the separability of the global BOLD signal from concurrent neurological processes motivated an examination of the global BOLD signal's spatial distribution. The results clarify that although the global signal collects information from all tissue classes, a diverse subset of the BOLD signal's independent components contribute the most to the global signal. Further, the timing of each network's contribution to the global signal is not consistent across volunteers, confirming the independence of a constituent process that comprises the global signal.

  20. Investigating Time-Varying Drivers of Grid Project Emissions Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Emily L.; Thayer, Brandon L.; Pal, Seemita; Studarus, Karen E.

    2017-11-15

    The emissions consequences of smart grid technologies depend heavily on their context and vary not only by geographical location, but by time of year. The same technology operated to meet the same objective may increase the emissions associated with energy generation for part of the year and decrease emissions during other times. The Grid Project Impact Quantification (GridPIQ) tool provides the ability to estimate these seasonal variations and garner insight into the time-varying drivers of grid project emissions impacts. This work leverages GridPIQ to examine the emissions implications across years and seasons of adding energy storage technology to reduce daily peak demand in California and New York.

  1. H∞ Control for a Networked Control Model of Systems with Two Additive Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Hanyong Shao

    2014-01-01

    Full Text Available This paper is concerned with H∞ control for a networked control model of systems with two additive time-varying delays. A new Lyapunov functional is constructed to make full use of the information of the delays, and for the derivative of the Lyapunov functional a novel technique is employed to compute a tighter upper bound, which is dependent on the two time-varying delays instead of the upper bounds of them. Then the convex polyhedron method is proposed to check the upper bound of the derivative of the Lyapunov functional. The resulting stability criteria have fewer matrix variables but less conservatism than some existing ones. The stability criteria are applied to designing a state feedback controller, which guarantees that the closed-loop system is asymptotically stable with a prescribed H∞ disturbance attenuation level. Finally examples are given to show the advantages of the stability criteria and the effectiveness of the proposed control method.

  2. The effect of varying protein levels on blood chemistry, food consumption, and behavior of captive seaducks

    Science.gov (United States)

    Wells-Berlin, A. M.; Perry, M.C.; Olsen, Glenn H.

    2005-01-01

    The Chesapeake Bay is a primary wintering area for scoters and the long-tailed ducks (Clangia hyemalis) that migrate along the Atlantic Flyway. Recently, the Chesapeake Bay had undergone an ecosystem shift and little is known about how this is affecting the seaduck populations. We are determining what are the preferred food sources of the seaducks wintering on the Bay and analyzing the factors influencing prey selection whether it is prey composition, energy assimilated, prey availability, or a combination of any or all of these factors. We have established a captive colony of surf (Melanitta perspicillata) and white-winged scoters (Melanitta fusca) as well as long-tailed ducks at Patuxent Wildlife Research Center to allow us to examine these factors in a more controlled environment. This project contains a multitude of experiments and the resultant data will be compiled into a compartmental model on the feeding ecology of seaducks wintering on the Bay. The first experiment entailed feeding groups of each species (four ducks per pen of equal sex ratio, if possible, and four pens per species) three diets varying in percent protein levels from November to February. Each diet was randomly assigned to each pen and the amount of food consumed was recorded each day. New feed was given when all existing food was consumed. Behavioral trials and blood profiles were completed on all study birds to determine the effects of the varying diets. There were no significant differences in food consumption, blood chemistry, and behavior detected at the 5% level among the diets for all three species of interest. There was a seasonal effect determined based on the food consumption data for white-winged scoters, but not for surf scoters or long-tailed ducks. The blood profiles of the surf scoters were compared to blood profiles of wild surf scoters and a there was no difference detected at the 5% level. As a health check of the ducks an aspergillosis test was run on the blood obtained

  3. Response of single bacterial cells to stress gives rise to complex history dependence at the population level

    Science.gov (United States)

    Mathis, Roland; Ackermann, Martin

    2016-01-01

    Most bacteria live in ever-changing environments where periods of stress are common. One fundamental question is whether individual bacterial cells have an increased tolerance to stress if they recently have been exposed to lower levels of the same stressor. To address this question, we worked with the bacterium Caulobacter crescentus and asked whether exposure to a moderate concentration of sodium chloride would affect survival during later exposure to a higher concentration. We found that the effects measured at the population level depended in a surprising and complex way on the time interval between the two exposure events: The effect of the first exposure on survival of the second exposure was positive for some time intervals but negative for others. We hypothesized that the complex pattern of history dependence at the population level was a consequence of the responses of individual cells to sodium chloride that we observed: (i) exposure to moderate concentrations of sodium chloride caused delays in cell division and led to cell-cycle synchronization, and (ii) whether a bacterium would survive subsequent exposure to higher concentrations was dependent on the cell-cycle state. Using computational modeling, we demonstrated that indeed the combination of these two effects could explain the complex patterns of history dependence observed at the population level. Our insight into how the behavior of single cells scales up to processes at the population level provides a perspective on how organisms operate in dynamic environments with fluctuating stress exposure. PMID:26960998

  4. Blood oxygenation level dependent (BOLD). Renal imaging. Concepts and applications

    International Nuclear Information System (INIS)

    Nissen, Johanna C.; Haneder, Stefan; Schoenberg, Stefan O.; Michaely, Henrik J.

    2010-01-01

    Many renal diseases as well as several pharmacons cause a change in renal blood flow and/or renal oxygenation. The blood oxygenation level dependent (BOLD) imaging takes advantage of local field inhomogeneities and is based on a T2 * -weighted sequence. BOLD is a non-invasive method allowing an estimation of the renal, particularly the medullary oxygenation, and an indirect measurement of blood flow without administration of contrast agents. Thus, effects of different drugs on the kidney and various renal diseases can be controlled and observed. This work will provide an overview of the studies carried out so far and identify ways how BOLD can be used in clinical studies. (orig.)

  5. Healthy and unhealthy dependence: implications for major depression.

    Science.gov (United States)

    Schulte, Fiona S; Mongrain, Myriam; Flora, David B

    2008-09-01

    To examine the contribution of varying levels of dependency to Axis I and Axis II disorders, and to the recurrence of major depression in a graduate student sample diagnosed with a history of the disorder. At Time 1, participants were interviewed to confirm a current or past episode of major depression along with the presence of Axis II and other current or past Axis I disorders. Various measures of dependency were administered including the Depressive Experiences Questionnaire (DEQ; Blatt, D'Afflitti, & Quinlan, 1976), the 3-Vector Dependency Inventory (3VDI; Pincus & Gurtman, 1995), and the Personal Style Inventory (PSI; Robins et al., 1994). Participants were interviewed 20 months later to determine the recurrence of a depressive episode. A factor analysis conducted on scale scores for each dependency measure resulted in three factors labelled 'unhealthy', 'intermediate', and 'healthy' dependence. Controlling for history of major depression, structural equation modelling found 'unhealthy' dependence to be the only predictor of recurrences of major depression and Axis II disorders, while 'healthy' dependence was related to fewer depressive symptoms. These results have important implications for the conceptualization of the dependency construct.

  6. Predicting Dropout Using Student- and School-Level Factors: An Ecological Perspective

    Science.gov (United States)

    Wood, Laura; Kiperman, Sarah; Esch, Rachel C.; Leroux, Audrey J.; Truscott, Stephen D.

    2017-01-01

    High school dropout has been associated with negative outcomes, including increased rates of unemployment, incarceration, and mortality. Dropout rates vary significantly depending on individual and environmental factors. The purpose of our study was to use an ecological perspective to concurrently explore student- and school-level predictors…

  7. Analysis of Two-Level Support Systems with Time-Dependent Overflow - A Banking Application

    DEFF Research Database (Denmark)

    Barth, Wolfgang; Manitz, Michael; Stolletz, Raik

    2010-01-01

    In this paper, we analyze the performance of call centers of financial service providers with two levels of support and a time-dependent overflow mechanism. Waiting calls from the front-office queue flow over to the back office if a waiting-time limit is reached and at least one back-office agent...

  8. On generalized scaling laws with continuously varying exponents

    International Nuclear Information System (INIS)

    Sittler, Lionel; Hinrichsen, Haye

    2002-01-01

    Many physical systems share the property of scale invariance. Most of them show ordinary power-law scaling, where quantities can be expressed as a leading power law times a scaling function which depends on scaling-invariant ratios of the parameters. However, some systems do not obey power-law scaling, instead there is numerical evidence for a logarithmic scaling form, in which the scaling function depends on ratios of the logarithms of the parameters. Based on previous ideas by Tang we propose that this type of logarithmic scaling can be explained by a concept of local scaling invariance with continuously varying exponents. The functional dependence of the exponents is constrained by a homomorphism which can be expressed as a set of partial differential equations. Solving these equations we obtain logarithmic scaling as a special case. The other solutions lead to scaling forms where logarithmic and power-law scaling are mixed

  9. GUAVA JUICE REDUCES CHOLESTEROL LEVEL FOR ELDERLY WITH HYPERTENSION

    OpenAIRE

    Afitasari, Dian Rahma; Yusuf, Ah.; Effendi, Fery

    2017-01-01

    Introduction: Hypertensive disease is closely related to high cholesterol level, which may act as one of causes of death in elderly. The objective of this study was to analyze the effect of guava juice on the reduction of cholesterol level of hypertensive elderly at Community Health Center, Pacar Keling, Surabaya. Method: Quasy–experimental was used in this study. Sample comprised of 14 respondents who met the inclusion criteria. The independent variable was guava juice and the dependent vari...

  10. Guava Juice Reduces Cholesterol Level for Elderly with Hypertension

    OpenAIRE

    Afitasari, Dian Rahma; Yusuf, Ah; Effendi, Fery

    2010-01-01

    Introduction: Hypertensive disease is closely related to high cholesterol level, which may act as one of causes of death in elderly. The objective of this study was to analyze the effect of guava juice on the reduction of cholesterol level of hypertensive elderly at Community Health Center, Pacar Keling, Surabaya. Method: Quasy–experimental was used in this study. Sample comprised of 14 respondents who met the inclusion criteria. The independent variable was guava juice and the dependent vari...

  11. Varying Constants, Gravitation and Cosmology

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Uzan

    2011-03-01

    Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  12. Newtonian cosmology with a time-varying constant of gravitation

    International Nuclear Information System (INIS)

    McVittie, G.C.

    1978-01-01

    Newtonian cosmology is based on the Eulerian equations of fluid mechanics combined with Poisson's equation modified by the introduction of a time-varying G. Spherically symmetric model universes are worked out with instantaneously uniform densities. They are indeterminate unless instantaneous uniformity of the pressure is imposed. When G varies as an inverse power of the time, the models can in some cases be shown to depend on the solution of a second-order differential equation which also occurs in the Friedmann models of general relativity. In Section 3, a method for 'passing through' a singularity of this equation is proposed which entails making four arbitrary mathematical assumptions. When G varies as (time) -1 , models with initially cycloidal motion are possible, each cycle becoming longer as time progresses. Finally, gravitation becomes so weak that the model expands to infinity. Kinetic and potential energies for the whole model are derived from the basic equations; their sum is not constant. (author)

  13. An optimal power-dispatching system using neural networks for the electrochemical process of zinc depending on varying prices of electricity.

    Science.gov (United States)

    Yang, Chunhua; Deconinck, G; Gui, Weihua; Li, Yonggang

    2002-01-01

    Depending on varying prices of electricity, an optimal power-dispatching system (OPDS) is developed to minimize the cost of power consumption in the electrochemical process of zinc (EPZ). Due to the complexity of the EPZ, the main factors influencing the power consumption are determined by qualitative analysis, and a series of conditional experiments is conducted to acquire sufficient data, then two backpropagation neural networks are used to describe these relationships quantitatively. An equivalent Hopfield neural network is constructed to solve the optimization problem where a penalty function is introduced into the network energy function so as to meet the equality constraints, and inequality constraints are removed by alteration of the Sigmoid function. This OPDS was put into service in a smeltery in 1998. The cost of power consumption has decreased significantly, the total electrical energy consumption is reduced, and it is also beneficial to balancing the load of the power grid. The actual results show the effectiveness of the OPDS. This paper introduces a successful industrial application and mainly presents how to utilize neural networks to solve particular problems for the real world.

  14. Self-perceived level of competitiveness, tension, and dependency and lifestyles in the 'Seguimiento Universidad de Navarra' cohort study.

    Science.gov (United States)

    Unzueta, C R; Lahortiga-Ramos, F; Santiago, S; Zazpe, I; Molero, P; Sánchez-Villegas, A; Martínez-González, M A

    2018-04-01

    The objective of this study is to assess the differences in lifestyles according to levels of self-perceived competitiveness, psychological tension, and dependency in a Mediterranean cohort of university graduates. Levels of personality traits, food consumption, nutrient intake, eating attitudes, physical activity, sedentary lifestyle, and alcohol and tobacco consumption were assessed through a questionnaire administered at baseline. This was a cross-sectional study in the context of the Seguimiento Universidad de Navarra cohort. Participants are 15,346 Spanish adults. Participants with a high level of self-perceived competitiveness consumed more vegetables and fish but less refined grains; they had higher protein intake and healthier eating attitudes. They were more physically active and less likely to be smokers. Participants with a high level of tension or dependency were less physically active, and participants more dependent also had poorer adherence to the Mediterranean diet. Self-perceived personality traits, especially the trait of competitiveness, are likely to be associated with healthier dietary patterns, better nutrient profile, better eating attitudes, physical activity, and less exposure to smoking. The use of short questions about self-perceived levels of competitiveness, psychological tension, and dependency can contribute to add additional information when assessing lifestyles and diet in adults. Copyright © 2018 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  15. Models of consumer behavior of households depending on the income level

    Directory of Open Access Journals (Sweden)

    Melnikova A.S.

    2016-11-01

    Full Text Available the consumer behavior of households is defined by a complex of internal and external factors: income of the population, motives and incentives of behavior, behavioral norms and personal preferences. As the example of structure analysis of the income and expenses of households of Sverdlovsk region during research models of consumer behavior of households are allocated, characteristics and structure of the population depending on their welfare are allocated. Author's approach allows forecasting of the consumer market, proceeding from the socio-economic factors forming the level of the population income in the region.

  16. Robust metabolic responses to varied carbon sources in natural and laboratory strains of Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Wayne A Van Voorhies

    Full Text Available Understanding factors that regulate the metabolism and growth of an organism is of fundamental biologic interest. This study compared the influence of two different carbon substrates, dextrose and galactose, on the metabolic and growth rates of the yeast Saccharomyces cerevisiae. Yeast metabolic and growth rates varied widely depending on the metabolic substrate supplied. The metabolic and growth rates of a yeast strain maintained under long-term laboratory conditions was compared to strain isolated from natural condition when grown on different substrates. Previous studies had determined that there are numerous genetic differences between these two strains. However, the overall metabolic and growth rates of a wild isolate of yeast was very similar to that of a strain that had been maintained under laboratory conditions for many decades. This indicates that, at in least this case, metabolism and growth appear to be well buffered against genetic differences. Metabolic rate and cell number did not co-vary in a simple linear manner. When grown in either dextrose or galactose, both strains showed a growth pattern in which the number of cells continued to increase well after the metabolic rate began a sharp decline. Previous studied have reported that O₂ consumption in S. cerevisiae grown in reduced dextrose levels were elevated compared to higher levels. Low dextrose levels have been proposed to induce caloric restriction and increase life span in yeast. However, there was no evidence that reduced levels of dextrose increased metabolic rates, measured by either O₂ consumption or CO₂ production, in the strains used in this study.

  17. Fermi level pinning by integer charge transfer at electrode-organic semiconductor interfaces

    NARCIS (Netherlands)

    Bokdam, Menno; Cakir, Deniz; Brocks, G.

    2011-01-01

    The atomic structure of interfaces between conducting electrodes and molecular organic materials varies considerably. Yet experiments show that pinning of the Fermi level, which is observed at such interfaces, does not depend upon the structural details. In this letter, we develop a general model to

  18. Audiovisual speech perception development at varying levels of perceptual processing

    OpenAIRE

    Lalonde, Kaylah; Holt, Rachael Frush

    2016-01-01

    This study used the auditory evaluation framework [Erber (1982). Auditory Training (Alexander Graham Bell Association, Washington, DC)] to characterize the influence of visual speech on audiovisual (AV) speech perception in adults and children at multiple levels of perceptual processing. Six- to eight-year-old children and adults completed auditory and AV speech perception tasks at three levels of perceptual processing (detection, discrimination, and recognition). The tasks differed in the le...

  19. Tenant Placement Strategies within Multi-Level Large-Scale Shopping Centers

    OpenAIRE

    Tony Shun-Te Yuo; Colin Lizieri

    2013-01-01

    This paper argues that tenant placement strategies for large-scale multi-unit shopping centers differ depending on the number of floor levels. Two core strategies are identified: dispersion and departmentalization. There exists a trade-off between three income effects: basic footfall effects, spillover effects, and an effective floor area effect, which varies by the number of floor levels. Departmentalization is favored for centers with more than four floors. Greater spatial complexity also p...

  20. Decentralized H∞ Control of Interconnected Systems with Time-varying Delays

    Directory of Open Access Journals (Sweden)

    Amal Zouhri

    2017-01-01

    Full Text Available This paper focuses on the problem of delay dependent stability/stabilization of interconnected systems with time-varying delays. The approach is based on a new Lyapunov-Krasovskii functional. A decentralized delay-dependent stability analysis is performed to characterize linear matrix inequalities (LMIs based on the conditions under which every local subsystem of the linear interconnected delay system is asymptotically stable. Then we design a decentralized state-feedback stabilization scheme such that the family of closedloop feedback subsystems enjoys the delay-dependent asymptotic stability for each subsystem. The decentralized feedback gains are determined by convex optimization over LMIs. All the developed results are tested on a representative example and compared with some recent previous ones.

  1. On the Perpetual American Put Options for Level Dependent Volatility Models with Jumps

    OpenAIRE

    Bayraktar, Erhan

    2007-01-01

    We prove that the perpetual American put option price of level dependent volatility model with compound Poisson jumps is convex and is the classical solution of its associated quasi-variational inequality, that it is $C^2$ except at the stopping boundary and that it is $C^1$ everywhere (i.e. the smooth pasting condition always holds).

  2. Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation

    OpenAIRE

    Licata, Stephanie C.; Lowen, Steven B.; Trksak, George H.; MacLean, Robert R.; Lukas, Scott E.

    2011-01-01

    Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABAA receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess...

  3. Influence of time dependent effects on the disposal environments of low and intermediate level radioactive wastes

    International Nuclear Information System (INIS)

    1984-12-01

    Reviews are presented firstly of potential events and processes which may affect the evolution of the disposal environments of low and intermediate level radioactive wastes in Britain and secondly of previous studies carried out worldwide in the field of time dependent effects. From the latter review available methodologies for incorporating time dependence into radiological assessments are identified. Finally, proposals are presented for the design and development of a time dependent effects model, based on the existing far field state model (FFSM) developed for ONWI in USA. (author)

  4. Sex differences in in-group cooperation vary dynamically with competitive conditions and outcomes.

    Science.gov (United States)

    Bailey, Drew H; Winegard, Benjamin; Oxford, Jon; Geary, David C

    2012-03-18

    Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male) young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus). In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

  5. Sex Differences in In-Group Cooperation Vary Dynamically with Competitive Conditions and Outcomes

    Directory of Open Access Journals (Sweden)

    Drew H. Bailey

    2012-01-01

    Full Text Available Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus. In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

  6. Exponential stability of switched linear systems with time-varying delay

    Directory of Open Access Journals (Sweden)

    Satiracoo Pairote

    2007-11-01

    Full Text Available We use a Lyapunov-Krasovskii functional approach to establish the exponential stability of linear systems with time-varying delay. Our delay-dependent condition allows to compute simultaneously the two bounds that characterize the exponential stability rate of the solution. A simple procedure for constructing switching rule is also presented.

  7. An Analysis of Some Variables Affecting the Internet Dependency Level of Turkish Adolescents by Using Decision Tree Methods

    Science.gov (United States)

    Kayri, Murat; Gunuc, Selim

    2010-01-01

    Internet dependency is going to expand into social life in wide area whereas it has been accepted as a pathological and psychological disease. Knowing the basic effects of internet dependency is an inevitable approach to use the internet technology healthy. In this study, internet dependency levels of 754 students were examined with the Internet…

  8. Slowly varying dilaton cosmologies and their field theory duals

    International Nuclear Information System (INIS)

    Awad, Adel; Das, Sumit R.; Ghosh, Archisman; Oh, Jae-Hyuk; Trivedi, Sandip P.

    2009-01-01

    We consider a deformation of the AdS 5 xS 5 solution of IIB supergravity obtained by taking the boundary value of the dilaton to be time dependent. The time dependence is taken to be slowly varying on the anti-de Sitter (AdS) scale thereby introducing a small parameter ε. The boundary dilaton has a profile which asymptotes to a constant in the far past and future and attains a minimum value at intermediate times. We construct the supergravity (sugra) solution to first nontrivial order in ε, and find that it is smooth, horizon-free, and asymptotically AdS 5 xS 5 in the far future. When the intermediate values of the dilaton becomes small enough the curvature becomes of order the string scale and the sugra approximation breaks down. The resulting dynamics is analyzed in the dual SU(N) gauge theory on S 3 with a time dependent coupling constant which varies slowly. When Nε 5 xS 5 again. When Nε>>1, we formulate a classical adiabatic perturbation theory based on coherent states which arises in the large N limit. For large values of the 't Hooft coupling this reproduces the supergravity results. For small 't Hooft coupling the coherent state calculations become involved and we cannot reach a definite conclusion. We argue that the final state should have a dual description which is mostly smooth AdS 5 space with the possible presence of a small black hole.

  9. Correlation analysis between bone density measured by quantitative CT and blood sugar level of aged patients with non-insulin-dependent diabetes mellitus

    International Nuclear Information System (INIS)

    Wang Guizhi; Liang Ping; Qiao Junhua; Liu Chunyan

    2008-01-01

    Objective: To approach the correlation between the bone density measured by quantitative CT and the blood sugar level of the aged patients with non-insulin-dependent diabetes mellitus, and observe the effects of the blood sugar level on the bone density. Methods: The lumbar bone densities and the blood sugar levels of 160 aged patients with non-insulin-dependent diabetes mellitus (hyperglycemia group 80 cases, euglycemia group 80 cases ) and the healthy aged people (80 cases) were detected by quantitative CT and serum biochemical detection; the correlation between the blood sugar level and the bone density and the osteoporosis occurrence status of aged people in various groups were analyzed. Results: The bone density in the non-insulin-dependent diabetes and hyperglycemia group was lower than those in normal (control) group and non-insulin-dependent diabetes and euglycemia group (P<0.05); the morbility of osteoporosis in the non-insulin-dependent diabetes and hyperglycemia group was higher than those in normal (control) group and non-insulin-dependent diabetes and euglycemia group (P<0.05); negative correlation was found between the bone density and the blood sugar level (aged male group: r=-0.7382, P=0.0013; aged female group: r=-0.8343, P=0.0007). Conclusion: The blood sugar level affects the bone density of the aged patients with non-insulin-dependent diabetes mellitus; the higher the blood sugar level, the lower the bone density. The non-insulin-dependent diabetes aged patients with hyperglycemia have the liability of osteoporosis. (authors)

  10. Modeling polar cap F-region patches using time varying convection

    International Nuclear Information System (INIS)

    Sojka, J.J.; Bowline, M.D.; Schunk, R.W.; Decker, D.T.; Valladares, C.E.; Sheehan, R.; Anderson, D.N.; Heelis, R.A.

    1993-01-01

    Here the authors present the results of computerized simulations of the polar cap regions which were able to model the formation of polar cap patches. They used the Utah State University Time-Dependent Ionospheric Model (TDIM) and the Phillips Laboratory (PL) F-region models in this work. By allowing a time varying magnetospheric electric field in the models, they were able to generate the patches. This time varying field generates a convection in the ionosphere. This convection is similar to convective changes observed in the ionosphere at times of southward pointing interplanetary magnetic field, due to changes in the B y component of the IMF

  11. Multi-Level Simulated Fault Injection for Data Dependent Reliability Analysis of RTL Circuit Descriptions

    Directory of Open Access Journals (Sweden)

    NIMARA, S.

    2016-02-01

    Full Text Available This paper proposes data-dependent reliability evaluation methodology for digital systems described at Register Transfer Level (RTL. It uses a hybrid hierarchical approach, combining the accuracy provided by Gate Level (GL Simulated Fault Injection (SFI and the low simulation overhead required by RTL fault injection. The methodology comprises the following steps: the correct simulation of the RTL system, according to a set of input vectors, hierarchical decomposition of the system into basic RTL blocks, logic synthesis of basic RTL blocks, data-dependent SFI for the GL netlists, and RTL SFI. The proposed methodology has been validated in terms of accuracy on a medium sized circuit – the parallel comparator used in Check Node Unit (CNU of the Low-Density Parity-Check (LDPC decoders. The methodology has been applied for the reliability analysis of a 128-bit Advanced Encryption Standard (AES crypto-core, for which the GL simulation was prohibitive in terms of required computational resources.

  12. Factors that affect the ecological footprint depending on the different income levels

    Directory of Open Access Journals (Sweden)

    Sheng-Tung Chen

    2016-05-01

    Full Text Available The ecological footprint provides a method for measuring how much lands can support the consumption of the natural resources. Development and biocapacity debates revolve mainly around the factors that affect the ecological footprint and the approaches to improve the environmental quality. Therefore, we conducted the panel analysis of data for 99 countries from 1981 to 2006 to determine what factors affect the ecological footprint. The empirical results show that the effect of GDP per capita on the ecological footprint varies for different income levels. The effect of urbanization is significantly positive across income levels, which means that the higher the rate of urbanization in high or low income country, the higher the ecological footprint. As developing countries pursue economic development, there will be an impact on the environment. The developed countries may seek to develop their economies through activities that are more detrimental to the environment. Additionally, the export of goods and services divided by GDP is significant, which means that the higher the volume of exports, the greater the burden on the environment. However, this effect is not significant across different income level models. The income effect may explain the diverse effects of export on the environment. Therefore, panel data analysis and income classification are necessary to discuss the effect of export on the environment.

  13. Emotions in freely varying and mono-pitched vowels, acoustic and EGG analyses.

    Science.gov (United States)

    Waaramaa, Teija; Palo, Pertti; Kankare, Elina

    2015-12-01

    Vocal emotions are expressed either by speech or singing. The difference is that in singing the pitch is predetermined while in speech it may vary freely. It was of interest to study whether there were voice quality differences between freely varying and mono-pitched vowels expressed by professional actors. Given their profession, actors have to be able to express emotions both by speech and singing. Electroglottogram and acoustic analyses of emotional utterances embedded in expressions of freely varying vowels [a:], [i:], [u:] (96 samples) and mono-pitched protracted vowels (96 samples) were studied. Contact quotient (CQEGG) was calculated using 35%, 55%, and 80% threshold levels. Three different threshold levels were used in order to evaluate their effects on emotions. Genders were studied separately. The results suggested significant gender differences for CQEGG 80% threshold level. SPL, CQEGG, and F4 were used to convey emotions, but to a lesser degree, when F0 was predetermined. Moreover, females showed fewer significant variations than males. Both genders used more hypofunctional phonation type in mono-pitched utterances than in the expressions with freely varying pitch. The present material warrants further study of the interplay between CQEGG threshold levels and formant frequencies, and listening tests to investigate the perceptual value of the mono-pitched vowels in the communication of emotions.

  14. Recognition for old Arabic manuscripts using spatial gray level dependence (SGLD

    Directory of Open Access Journals (Sweden)

    Ahmad M. Abd Al-Aziz

    2011-03-01

    Full Text Available Texture analysis forms the basis of object recognition and classification in several domains, one of these domains is historical document manuscripts because the manuscripts hold our culture heritage and also large numbers of undated manuscripts exist. This paper presents results for historical document classification of old Arabic manuscripts using texture analysis and a segmentation free approach. The main objective is to discriminate between historical documents of different writing styles to three different ages: Contemporary (Modern Age, Ottoman Age and Mamluk Age. This classification depends on a Spatial Gray-level Dependence (SGLD technique which provides eight distinct texture features for each sample document. We applied Stepwise Discriminant Analysis and Multiple discriminant analysis methods to decrease the dimensionality of features and extract training vector features from samples. To classify historical documents into three main historical age classes the decision tree classification is applied. The system has been tested on 48 Arabic historical manuscripts documents from the Dar Al-Kotob Al-Masria Library. Our results so far yield 95.83% correct classification for the historical Arabic documents.

  15. Modelling Time-Varying Volatility in Financial Returns

    DEFF Research Database (Denmark)

    Amado, Cristina; Laakkonen, Helinä

    2014-01-01

    The “unusually uncertain” phase in the global financial markets has inspired many researchers to study the effects of ambiguity (or “Knightian uncertainty”) on the decisions made by investors and their implications for the capital markets. We contribute to this literature by using a modified...... version of the time-varying GARCH model of Amado and Teräsvirta (2013) to analyze whether the increasing uncertainty has caused excess volatility in the US and European government bond markets. In our model, volatility is multiplicatively decomposed into two time-varying conditional components: the first...... being captured by a stable GARCH(1,1) process and the second driven by the level of uncertainty in the financial market....

  16. Experimental examination of intraspecific density-dependent competition during the breeding period in monarch butterflies (Danaus plexippus.

    Directory of Open Access Journals (Sweden)

    D T Tyler Flockhart

    Full Text Available A central goal of population ecology is to identify the factors that regulate population growth. Monarch butterflies (Danaus plexippus in eastern North America re-colonize the breeding range over several generations that result in population densities that vary across space and time during the breeding season. We used laboratory experiments to measure the strength of density-dependent intraspecific competition on egg laying rate and larval survival and then applied our results to density estimates of wild monarch populations to model the strength of density dependence during the breeding season. Egg laying rates did not change with density but larvae at high densities were smaller, had lower survival, and weighed less as adults compared to lower densities. Using mean larval densities from field surveys resulted in conservative estimates of density-dependent population reduction that varied between breeding regions and different phases of the breeding season. Our results suggest the highest levels of population reduction due to density-dependent intraspecific competition occur early in the breeding season in the southern portion of the breeding range. However, we also found that the strength of density dependence could be almost five times higher depending on how many life-stages were used as part of field estimates. Our study is the first to link experimental results of a density-dependent reduction in vital rates to observed monarch densities in the wild and show that the effects of density dependent competition in monarchs varies across space and time, providing valuable information for developing robust, year-round population models in this migratory organism.

  17. The effect of varying alveolar carbon dioxide levels on free recall.

    Science.gov (United States)

    Marangoni, A H; Hurford, D P

    1990-05-01

    A recent study suggested that students who have increased minute ventilation receive poorer grades. The present study was interested in determining the role alveolar carbon dioxide (CO2) levels play with cognitive abilities. A free recall task was used to examine list learning under two conditions of alveolar CO2 level: normal and decreased. The results suggested that decreased alveolar CO2 level affect the participant's ability to rehearse and recall information. It was concluded that conditions that reduce alveolar CO2 levels, such as hyperventilation resulting from stress, nervousness, or inappropriate breathing habits, can lead to poorer learning. If these conditions produce a habitual breathing pattern, the academic performance of the individual may suffer.

  18. Spinal cord injury-induced immune deficiency syndrome enhances infection susceptibility dependent on lesion level.

    Science.gov (United States)

    Brommer, Benedikt; Engel, Odilo; Kopp, Marcel A; Watzlawick, Ralf; Müller, Susanne; Prüss, Harald; Chen, Yuying; DeVivo, Michael J; Finkenstaedt, Felix W; Dirnagl, Ulrich; Liebscher, Thomas; Meisel, Andreas; Schwab, Jan M

    2016-03-01

    Pneumonia is the leading cause of death after acute spinal cord injury and is associated with poor neurological outcome. In contrast to the current understanding, attributing enhanced infection susceptibility solely to the patient's environment and motor dysfunction, we investigate whether a secondary functional neurogenic immune deficiency (spinal cord injury-induced immune deficiency syndrome, SCI-IDS) may account for the enhanced infection susceptibility. We applied a clinically relevant model of experimental induced pneumonia to investigate whether the systemic SCI-IDS is functional sufficient to cause pneumonia dependent on spinal cord injury lesion level and investigated whether findings are mirrored in a large prospective cohort study after human spinal cord injury. In a mouse model of inducible pneumonia, high thoracic lesions that interrupt sympathetic innervation to major immune organs, but not low thoracic lesions, significantly increased bacterial load in lungs. The ability to clear the bacterial load from the lung remained preserved in sham animals. Propagated immune susceptibility depended on injury of central pre-ganglionic but not peripheral postganglionic sympathetic innervation to the spleen. Thoracic spinal cord injury level was confirmed as an independent increased risk factor of pneumonia in patients after motor complete spinal cord injury (odds ratio = 1.35, P spinal cord injury directly causes increased risk for bacterial infection in mice as well as in patients. Besides obvious motor and sensory paralysis, spinal cord injury also induces a functional SCI-IDS ('immune paralysis'), sufficient to propagate clinically relevant infection in an injury level dependent manner. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Time-varying auditory gain control in response to double-pulse stimuli in harbour porpoises is not mediated by a stapedial reflex

    Directory of Open Access Journals (Sweden)

    Asger Emil Munch Schrøder

    2017-04-01

    Full Text Available Echolocating animals reduce their output level and hearing sensitivity with decreasing echo delays, presumably to stabilize the perceived echo intensity during target approaches. In bats, this variation in hearing sensitivity is formed by a call-induced stapedial reflex that tapers off over time after the call. Here, we test the hypothesis that a similar mechanism exists in toothed whales by subjecting a trained harbour porpoise to a series of double sound pulses varying in delay and frequency, while measuring the magnitudes of the evoked auditory brainstem responses (ABRs. We find that the recovery of the ABR to the second pulse is frequency dependent, and that a stapedial reflex therefore cannot account for the reduced hearing sensitivity at short pulse delays. We propose that toothed whale auditory time-varying gain control during echolocation is not enabled by the middle ear as in bats, but rather by frequency-dependent mechanisms such as forward masking and perhaps higher-order control of efferent feedback to the outer hair cells.

  20. Time-varying correlation and common structures in volatility

    NARCIS (Netherlands)

    Liu, Yang

    2016-01-01

    This thesis studies time series properties of the covariance structure of multivariate asset returns. First, the time-varying feature of correlation is investigated at the intraday level with a new correlation model incorporating the intraday correlation dynamics. Second, the thesis develops a

  1. CO2-level Dependent Effects of Ocean Acidification on Squid, Doryteuthis pealeii, Early Life History

    KAUST Repository

    Zakroff, Casey J.

    2013-12-01

    Ocean acidification is predicted to lead to global oceanic decreases in pH of up to 0.3 units within the next 100 years. However, those levels are already being reached currently in coastal regions due to natural CO2 variability. Squid are a vital component of the pelagic ecosystem, holding a unique niche as a highly active predatory invertebrate and major prey stock for upper trophic levels. This study examined the effects of a range of ocean acidification regimes on the early life history of a coastal squid species, the Atlantic longfin squid, Doryteuthis pealeii. Eggs were raised in a flow-through ocean acidification system at CO2 levels ranging from ambient (400ppm) to 2200ppm. Time to hatching, hatching efficiency, and hatchling mantle lengths, yolk sac sizes, and statoliths were all examined to elucidate stress effects. Delays in hatching time of at least a day were seen at exposures above 1300ppm in all trials under controlled conditions. Mantle lengths were significantly reduced at exposures above 1300 ppm. Yolk sac sizes varied between CO2 treatments, but no distinct pattern emerged. Statoliths were increasingly porous and malformed as CO2 exposures increased, and were significantly reduced in surface area at exposures above 1300ppm. Doryteuthis pealeii appears to be able to withstand acidosis stress without major effects up to 1300ppm, but is strongly impacted past that threshold. Since yolk consumption did not vary among treatments, it appears that during its early life stages, D. pealeii reallocates its available energy budget away from somatic growth and system development in order to mitigate the stress of acidosis.

  2. Vitamin A degradation in triglycerides varying by their saturation levels.

    Science.gov (United States)

    Moccand, Cyril; Martin, Fréderic; Martiel, Isabelle; Gancel, Charlotte; Michel, Martin; Fries, Lennart; Sagalowicz, Laurent

    2016-10-01

    Vitamin A deficiency has a widespread occurrence globally and is considered as one of the world's most serious health risk factors. Potential solutions to address this deficiency include dietary diversification or supplementation, but food fortification is generally accepted as the most cost-effective solution. The main issue with food fortification of this vitamin is related to its high instability in food matrices. Dilution of vitamin A in triglycerides is a natural and appropriate way to stabilize this compound. We show here that vitamin A palmitate stability increases with increasing concentration of triglycerides. Moreover, we found that vitamin A palmitate displays improved stability in more saturated oils. Using various temperatures, and Arrhenius plots of experiments performed at storage temperatures between 30°C and 60°C for oils varying by their saturation and crystallinity, we demonstrate that crystallization is not responsible for this phenomenon. Additionally, we show by centrifugation that vitamin A is preferably solubilized in the liquid phase compared to the crystalline phase, explaining that triglyceride crystallization does not stabilize vitamin A palmitate. It is proposed that unsaturated fats generate more oxidation products such as radicals and peroxides, leading to a quicker degradation of vitamin A. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. TNFα dynamics during the oral glucose tolerance test vary according to the level of insulin resistance in pregnant women.

    Science.gov (United States)

    Guillemette, Laetitia; Lacroix, Marilyn; Battista, Marie-Claude; Doyon, Myriam; Moreau, Julie; Ménard, Julie; Ardilouze, Jean-Luc; Perron, Patrice; Hivert, Marie-France

    2014-05-01

    TNFα is suspected to play a role in inflammation and insulin resistance leading to higher risk of metabolic impairment. Controversies exist concerning the role of TNFα in gestational insulin resistance. We investigated the interrelations between TNFα and insulin resistance in a large population-based cohort of pregnant women. Women (n = 756) were followed prospectively at 5-16 weeks and 24-28 weeks of pregnancy. Anthropometric measures and blood samples were collected at both visits. A 75-g oral glucose tolerance test (OGTT) was conducted at the second trimester to assess insulin sensitivity status (homeostasis model of assessment of insulin resistance and Matsuda index). TNFα was measured at the first trimester (nonfasting) and at each time point of the OGTT. Participants were 28.4 ± 4.4 years old and had a mean body mass index of 25.5 ± 5.5 kg/m(2) at first trimester. Median TNFα levels were 1.56 (interquartile range, 1.18-2.06) pg/mL at first trimester and 1.61 (interquartile range, 1.12-2.13) pg/mL at second trimester (1 h after glucose load). At second trimester, higher TNFα levels were associated with higher insulin resistance index levels (r = 0.37 and -0.30 for homeostasis model of assessment of insulin resistance and Matsuda index, respectively; P insulin resistance showed a continuing decrease in TNFα levels during the OGTT, whereas women who were more insulin sensitive showed an increase in TNFα at hour 1 and a decrease at hour 2 of the test. Higher insulin resistance is associated with higher levels of circulating TNFα at first and second trimesters of pregnancy. TNFα level dynamics during an OGTT at second trimester vary according to insulin-resistance state.

  4. Sub-national mapping of population pyramids and dependency ratios in Africa and Asia

    Science.gov (United States)

    Pezzulo, Carla; Hornby, Graeme M.; Sorichetta, Alessandro; Gaughan, Andrea E.; Linard, Catherine; Bird, Tomas J.; Kerr, David; Lloyd, Christopher T.; Tatem, Andrew J.

    2017-07-01

    The age group composition of populations varies substantially across continents and within countries, and is linked to levels of development, health status and poverty. The subnational variability in the shape of the population pyramid as well as the respective dependency ratio are reflective of the different levels of development of a country and are drivers for a country's economic prospects and health burdens. Whether measured as the ratio between those of working age and those young and old who are dependent upon them, or through separate young and old-age metrics, dependency ratios are often highly heterogeneous between and within countries. Assessments of subnational dependency ratio and age structure patterns have been undertaken for specific countries and across high income regions, but to a lesser extent across the low income regions. In the framework of the WorldPop Project, through the assembly of over 100 million records across 6,389 subnational administrative units, subnational dependency ratio and high resolution gridded age/sex group datasets were produced for 87 countries in Africa and Asia.

  5. Effect of a time varying power level in EBR-II on mixed-oxide fuel burnup

    International Nuclear Information System (INIS)

    Stone, I.Z.; Jost, J.W.; Baker, R.B.

    1979-01-01

    A refined prediction of burnup of mixed-oxide fuel in EBR-2 is compared with measured data. The calculation utilizes a time-varying power factor and results in a general improvement to previous calculations

  6. On the dependence of the OH* Meinel emission altitude on vibrational level: SCIAMACHY observations and model simulations

    Directory of Open Access Journals (Sweden)

    J. P. Burrows

    2012-09-01

    Full Text Available Measurements of the OH Meinel emissions in the terrestrial nightglow are one of the standard ground-based techniques to retrieve upper mesospheric temperatures. It is often assumed that the emission peak altitudes are not strongly dependent on the vibrational level, although this assumption is not based on convincing experimental evidence. In this study we use Envisat/SCIAMACHY (Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY observations in the near-IR spectral range to retrieve vertical volume emission rate profiles of the OH(3-1, OH(6-2 and OH(8-3 Meinel bands in order to investigate whether systematic differences in emission peak altitudes can be observed between the different OH Meinel bands. The results indicate that the emission peak altitudes are different for the different vibrational levels, with bands originating from higher vibrational levels having higher emission peak altitudes. It is shown that this finding is consistent with the majority of the previously published results. The SCIAMACHY observations yield differences in emission peak altitudes of up to about 4 km between the OH(3-1 and the OH(8-3 band. The observations are complemented by model simulations of the fractional population of the different vibrational levels and of the vibrational level dependence of the emission peak altitude. The model simulations reproduce the observed vibrational level dependence of the emission peak altitude well – both qualitatively and quantitatively – if quenching by atomic oxygen as well as multi-quantum collisional relaxation by O2 is considered. If a linear relationship between emission peak altitude and vibrational level is assumed, then a peak altitude difference of roughly 0.5 km per vibrational level is inferred from both the SCIAMACHY observations and the model simulations.

  7. Physiologic response to varying levels of pressure support and neurally adjusted ventilatory assist in patients with acute respiratory failure.

    Science.gov (United States)

    Colombo, Davide; Cammarota, Gianmaria; Bergamaschi, Valentina; De Lucia, Marta; Corte, Francesco Della; Navalesi, Paolo

    2008-11-01

    Neurally adjusted ventilatory assist (NAVA) is a new mode wherein the assistance is provided in proportion to diaphragm electrical activity (EAdi). We assessed the physiologic response to varying levels of NAVA and pressure support ventilation (PSV). ICU of a University Hospital. Fourteen intubated and mechanically ventilated patients. DESIGN AND PROTOCOL: Cross-over, prospective, randomized controlled trial. PSV was set to obtain a VT/kg of 6-8 ml/kg with an active inspiration. NAVA was matched with a dedicated software. The assistance was decreased and increased by 50% with both modes. The six assist levels were randomly applied. Arterial blood gases (ABGs), tidal volume (VT/kg), peak EAdi, airway pressure (Paw), neural and flow-based timing. Asynchrony was calculated using the asynchrony index (AI). There was no difference in ABGs regardless of mode and assist level. The differences in breathing pattern, ventilator assistance, and respiratory drive and timing between PSV and NAVA were overall small at the two lower assist levels. At the highest assist level, however, we found greater VT/kg (9.1 +/- 2.2 vs. 7.1 +/- 2 ml/kg, P < 0.001), and lower breathing frequency (12 +/- 6 vs. 18 +/- 8.2, P < 0.001) and peak EAdi (8.6 +/- 10.5 vs. 12.3 +/- 9.0, P < 0.002) in PSV than in NAVA; we found mismatch between neural and flow-based timing in PSV, but not in NAVA. AI exceeded 10% in five (36%) and no (0%) patients with PSV and NAVA, respectively (P < 0.05). Compared to PSV, NAVA averted the risk of over-assistance, avoided patient-ventilator asynchrony, and improved patient-ventilator interaction.

  8. Anatomical and Physiological Responses of Citrus Trees to Varying Boron Availability Are Dependent on Rootstock.

    Science.gov (United States)

    Mesquita, Geisa L; Zambrosi, Fernando C B; Tanaka, Francisco A O; Boaretto, Rodrigo M; Quaggio, José A; Ribeiro, Rafael V; Mattos, Dirceu

    2016-01-01

    In Citrus, water, nutrient transport and thereby fruit production, are influenced among other factors, by the interaction between rootstock and boron (B) nutrition. This study aimed to investigate how B affects the anatomical structure of roots and leaves as well as leaf gas exchange in sweet orange trees grafted on two contrasting rootstocks in response to B supply. Plants grafted on Swingle citrumelo or Sunki mandarin were grown in a nutrient solution of varying B concentration (deficient, adequate, and excessive). Those grafted on Swingle were more tolerant to both B deficiency and toxicity than those on Sunki, as revealed by higher shoot and root growth. In addition, plants grafted on Sunki exhibited more severe anatomical and physiological damages under B deficiency, showing thickening of xylem cell walls and impairments in whole-plant leaf-specific hydraulic conductance and leaf CO2 assimilation. Our data revealed that trees grafted on Swingle sustain better growth under low B availablitlity in the root medium and still respond positively to increased B levels by combining higher B absorption and root growth as well as better organization of xylem vessels. Taken together, those traits improved water and B transport to the plant canopy. Under B toxicity, Swingle rootstock would also favor plant growth by reducing anatomical and ultrastructural damage to leaf tissue and improving water transport compared with plants grafted on Sunki. From a practical point of view, our results highlight that B management in citrus orchards shall take into account rootstock varieties, of which the Swingle rootstock was characterized by its performance on regulating anatomical and ultrastructural damages, improving water transport and limiting negative impacts of B stress conditions on plant growth.

  9. Performance of Traffic Noise Barriers with Varying Cross-Section

    Directory of Open Access Journals (Sweden)

    Sanja Grubeša

    2011-05-01

    Full Text Available The efficiency of noise barriers largely depends on their geometry. In this paper, the performance of noise barriers was simulated using the numerical Boundary Element Method (BEM. Traffic noise was particularly considered with its standardized noise spectrum adapted to human hearing. The cross-section of the barriers was varied with the goal of finding the optimum shape in comparison to classical rectangular barriers. The barrier performance was calculated at different receiver points for a fixed barrier height and source position. The magnitude of the insertion loss parameter was used to evaluate the performance change, both in one-third octave bands and as the broadband mean insertion loss value. The proposed barriers of varying cross-section were also compared with a typical T-shape barrier of the same height.

  10. Epidemic spreading in time-varying community networks.

    Science.gov (United States)

    Ren, Guangming; Wang, Xingyuan

    2014-06-01

    The spreading processes of many infectious diseases have comparable time scale as the network evolution. Here, we present a simple networks model with time-varying community structure, and investigate susceptible-infected-susceptible epidemic spreading processes in this model. By both theoretic analysis and numerical simulations, we show that the efficiency of epidemic spreading in this model depends intensively on the mobility rate q of the individuals among communities. We also find that there exists a mobility rate threshold qc. The epidemic will survive when q > qc and die when q epidemic spreading in complex networks with community structure.

  11. Integrative curriculum reform, domain dependent knowing, and teachers` epistemological theories: Implications for middle-level teaching

    Energy Technology Data Exchange (ETDEWEB)

    Powell, R.R. [Texas Tech Univ., Lubbock, TX (United States). College of Education

    1998-12-01

    Integrative curriculum as both a theoretical construct and a practical reality, and as a theme-based, problem-centered, democratic way of schooling, is becoming more widely considered as a feasible alternative to traditional middle-level curricula. Importantly for teaching and learning, domain dependence requires teachers to view one area of knowledge as fully interdependent with other areas of knowledge during the learning process. This requires teachers to adopt personal epistemological theories that reflect integrative, domain dependent knowing. This study explored what happened when teachers from highly traditional domain independent school settings encountered an ambitious college-level curriculum project that was designed to help the teachers understand the potential that integrative, domain dependent teaching holds for precollege settings. This study asked: What influence does an integrative, domain dependent curriculum project have on teachers` domain independent, epistemological theories for teaching and learning? Finding an answer to this question is essential if we, as an educational community, are to understand how integrative curriculum theory is transformed by teachers into systemic curriculum reform. The results suggest that the integrative curriculum project that teachers participated in did not explicitly alter their classroom practices in a wholesale manner. Personal epistemological theories of teachers collectively precluded teachers from making any wholesale changes in their individual classroom teaching. However, teachers became aware of integrative curriculum as an alternative, and they expressed interest in infusing integrative practices into their classrooms as opportunities arise.

  12. LiDAR based prediction of forest biomass using hierarchical models with spatially varying coefficients

    Science.gov (United States)

    Babcock, Chad; Finley, Andrew O.; Bradford, John B.; Kolka, Randall K.; Birdsey, Richard A.; Ryan, Michael G.

    2015-01-01

    Many studies and production inventory systems have shown the utility of coupling covariates derived from Light Detection and Ranging (LiDAR) data with forest variables measured on georeferenced inventory plots through regression models. The objective of this study was to propose and assess the use of a Bayesian hierarchical modeling framework that accommodates both residual spatial dependence and non-stationarity of model covariates through the introduction of spatial random effects. We explored this objective using four forest inventory datasets that are part of the North American Carbon Program, each comprising point-referenced measures of above-ground forest biomass and discrete LiDAR. For each dataset, we considered at least five regression model specifications of varying complexity. Models were assessed based on goodness of fit criteria and predictive performance using a 10-fold cross-validation procedure. Results showed that the addition of spatial random effects to the regression model intercept improved fit and predictive performance in the presence of substantial residual spatial dependence. Additionally, in some cases, allowing either some or all regression slope parameters to vary spatially, via the addition of spatial random effects, further improved model fit and predictive performance. In other instances, models showed improved fit but decreased predictive performance—indicating over-fitting and underscoring the need for cross-validation to assess predictive ability. The proposed Bayesian modeling framework provided access to pixel-level posterior predictive distributions that were useful for uncertainty mapping, diagnosing spatial extrapolation issues, revealing missing model covariates, and discovering locally significant parameters.

  13. Anistropically varying conductivity in irreversible electroporation simulations.

    Science.gov (United States)

    Labarbera, Nicholas; Drapaca, Corina

    2017-11-01

    One recent area of cancer research is irreversible electroporation (IRE). Irreversible electroporation is a minimally invasive procedure where needle electrodes are inserted into the body to ablate tumor cells with electricity. The aim of this paper is to propose a mathematical model that incorporates a tissue's conductivity increasing more in the direction of the electrical field as this has been shown to occur in experiments. It was necessary to mathematically derive a valid form of the conductivity tensor such that it is dependent on the electrical field direction and can be easily implemented into numerical software. The derivation of a conductivity tensor that can take arbitrary functions for the conductivity in the directions tangent and normal to the electrical field is the main contribution of this paper. Numerical simulations were performed for isotropic-varying and anisotropic-varying conductivities to evaluate the importance of including the electrical field's direction in the formulation for conductivity. By starting from previously published experimental results, this paper derived a general formulation for an anistropic-varying tensor for implementation into irreversible electroporation modeling software. The anistropic-varying tensor formulation allows the conductivity to take into consideration both electrical field direction and magnitude, as opposed to previous published works that only took into account electrical field magnitude. The anisotropic formulation predicts roughly a five percent decrease in ablation size for the monopolar simulation and approximately a ten percent decrease in ablation size for the bipolar simulations. This is a positive result as previously reported results found the isotropic formulation to overpredict ablation size for both monopolar and bipolar simulations. Furthermore, it was also reported that the isotropic formulation overpredicts the ablation size more for the bipolar case than the monopolar case. Thus, our

  14. MORTALITY FROM SUICIDE AND ALCOHOLISM, DEPENDING ON THE LEVEL OF ALCOHOL CONSUMPTION

    Directory of Open Access Journals (Sweden)

    L. A. Radkevich

    2017-01-01

    Full Text Available According to WHO, the world takes place every year approximately 500 000 suicides and suicide attempts of 7 million. Since 1994, Russia ranks 2nd in the world after Lithuania, in the level of suicides, and is among the countries with the linear dependence of frequency of suicides on the level of alcohol consumption.Purpose. Install a quantitative connection between the frequency of suicide with alcohol consumption and mortality from alcoholism in the world.Material and method. For studies we used the mortality coefficient (MK from suicide and alcohol abuse (number of people/100 thousand of age standardized the population in 159 countries according to the WHO in 2004, the average daily consumption levels of alcoholic beverages: spirits, wine and beer (g/person/day according to the FAO (Food and Agriculture Organization of the United Nations. For data analysis we used correlation and regression methods.Results. We found significant positive correlation of mortality coefficient (MK from suicide for men and women with consumption of alcoholic beverages (spirits, wine and beer and mortality from alcoholism. The gender differences are revealed. Included in the regression model independent variables (levels of alcohol consumption and mortality from alcoholism explain 66% and 52% of the variability in the frequency of suicides of men and women (dependent variables. A complete rejection of the consumption of alcohol reduces the MK from suicide of men in the world at 39.5 percent, in Russia — at 76.5%; women — 37.9%, in Russia — by 54.3%. According to the regression analysis the average daily level of consumption of strong alcohol in the world is 10.4 g (3.8 kg per year for men, in Russia — 91.8 g (of 33.5 kg per year. The increase in the consumption of strong alcohol to 3 g per day (1 kg per year increases the MK from suicide in men up to 10.8% (1.6 people in the world, in Russia — 2.4% (1.6 people. The increase in the MK of alcoholism of men

  15. Monolayer phosphorene under time-dependent magnetic field

    Science.gov (United States)

    Nascimento, J. P. G.; Aguiar, V.; Guedes, I.

    2018-02-01

    We obtain the exact wave function of a monolayer phosphorene under a low-intensity time-dependent magnetic field using the dynamical invariant method. We calculate the quantum-mechanical energy expectation value and the transition probability for a constant and an oscillatory magnetic field. For the former we observe that the Landau level energy varies linearly with the quantum numbers n and m and the magnetic field intensity B0. No transition takes place. For the latter, we observe that the energy oscillates in time, increasing linearly with the Landau level n and m and nonlinearly with the magnetic field. The (k , l) →(n , m) transitions take place only for l = m. We investigate the (0,0) →(n , 0) and (1 , l) and (2 , l) probability transitions.

  16. Influence of feeding varying crude protein and digestible energy ...

    African Journals Online (AJOL)

    Influence of feeding varying crude protein and digestible energy levels on the development of individual muscles, rate of lean and fat deposition in pigs reared from 9 to 60kg liveweight in a humid tropical environment.

  17. Effects of BDNF receptor antagonist on the severity of physical and psychological dependence, morphine-induced locomotor sensitization and the ventral tegmental area-nucleus accumbens BDNF levels in morphine- dependent and withdrawn rats.

    Science.gov (United States)

    Khalil-Khalili, Masoumeh; Rashidy-Pour, Ali; Bandegi, Ahmad Reza; Yousefi, Behpoor; Jorjani, Hassan; Miladi-Gorji, Hossein

    2018-03-06

    This study examined the effects of systemic administration of the TrkB receptor antagonist (ANA-12) on the severity of physical and psychological dependence and morphine-induced locomotor sensitization, the ventral tegmental area (VTA)-nucleus accumbens (NAc) BDNF levels in morphine-dependent and withdrawn rats. Rats were injected with bi-daily doses (10 mg/kg, at 12 h intervals) of morphine for 10 days. Then, rats were tested for naloxone-precipitated morphine withdrawal signs, the anxiety (the elevated plus maze-EPM) after the last morphine injection and injection of ANA12 (ip). Also, morphine-induced locomotor sensitization was evaluated after morphine challenge followed by an injection of ANA-12 in morphine-withdrawn rats. The VTA-NAc BDNF levels were assessed in morphine-dependent and withdrawn rats. The overall Gellert-Holtzman score was significantly higher in morphine-dependent rats receiving ANA-12 than in those receiving saline. Also, the percentage of time spent in the open arms in control and morphine-dependent rats receiving ANA-12 were higher compared to the Cont/Sal and D/Sal rats, respectively. There was no significant difference in the locomotor activity and the VTA-NAc BDNF levels between D/Sal/morphine and D/ANA-12/morphine groups after morphine withdrawal. We conclude that the systemic administration of ANA-12 exacerbates the severity of physical dependence on morphine and partially attenuates the anxiety-like behavior in morphine-dependent rats. However, ANA-12 did not affect morphine-induced locomotor sensitization and the VTA-NAc BDNF levels in morphine-dependent and withdrawn rats. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Delay-Dependent Stability Criterion for Bidirectional Associative Memory Neural Networks with Interval Time-Varying Delays

    Science.gov (United States)

    Park, Ju H.; Kwon, O. M.

    In the letter, the global asymptotic stability of bidirectional associative memory (BAM) neural networks with delays is investigated. The delay is assumed to be time-varying and belongs to a given interval. A novel stability criterion for the stability is presented based on the Lyapunov method. The criterion is represented in terms of linear matrix inequality (LMI), which can be solved easily by various optimization algorithms. Two numerical examples are illustrated to show the effectiveness of our new result.

  19. Language experience enhances early cortical pitch-dependent responses

    Science.gov (United States)

    Krishnan, Ananthanarayan; Gandour, Jackson T.; Ananthakrishnan, Saradha; Vijayaraghavan, Venkatakrishnan

    2014-01-01

    Pitch processing at cortical and subcortical stages of processing is shaped by language experience. We recently demonstrated that specific components of the cortical pitch response (CPR) index the more rapidly-changing portions of the high rising Tone 2 of Mandarin Chinese, in addition to marking pitch onset and sound offset. In this study, we examine how language experience (Mandarin vs. English) shapes the processing of different temporal attributes of pitch reflected in the CPR components using stimuli representative of within-category variants of Tone 2. Results showed that the magnitude of CPR components (Na-Pb and Pb-Nb) and the correlation between these two components and pitch acceleration were stronger for the Chinese listeners compared to English listeners for stimuli that fell within the range of Tone 2 citation forms. Discriminant function analysis revealed that the Na-Pb component was more than twice as important as Pb-Nb in grouping listeners by language affiliation. In addition, a stronger stimulus-dependent, rightward asymmetry was observed for the Chinese group at the temporal, but not frontal, electrode sites. This finding may reflect selective recruitment of experience-dependent, pitch-specific mechanisms in right auditory cortex to extract more complex, time-varying pitch patterns. Taken together, these findings suggest that long-term language experience shapes early sensory level processing of pitch in the auditory cortex, and that the sensitivity of the CPR may vary depending on the relative linguistic importance of specific temporal attributes of dynamic pitch. PMID:25506127

  20. Detection of random alterations to time-varying musical instrument spectra.

    Science.gov (United States)

    Horner, Andrew; Beauchamp, James; So, Richard

    2004-09-01

    The time-varying spectra of eight musical instrument sounds were randomly altered by a time-invariant process to determine how detection of spectral alteration varies with degree of alteration, instrument, musical experience, and spectral variation. Sounds were resynthesized with centroids equalized to the original sounds, with frequencies harmonically flattened, and with average spectral error levels of 8%, 16%, 24%, 32%, and 48%. Listeners were asked to discriminate the randomly altered sounds from reference sounds resynthesized from the original data. For all eight instruments, discrimination was very good for the 32% and 48% error levels, moderate for the 16% and 24% error levels, and poor for the 8% error levels. When the error levels were 16%, 24%, and 32%, the scores of musically experienced listeners were found to be significantly better than the scores of listeners with no musical experience. Also, in this same error level range, discrimination was significantly affected by the instrument tested. For error levels of 16% and 24%, discrimination scores were significantly, but negatively correlated with measures of spectral incoherence and normalized centroid deviation on unaltered instrument spectra, suggesting that the presence of dynamic spectral variations tends to increase the difficulty of detecting spectral alterations. Correlation between discrimination and a measure of spectral irregularity was comparatively low.

  1. Task-dependent output of human parasternal intercostal motor units across spinal levels.

    Science.gov (United States)

    Hudson, Anna L; Gandevia, Simon C; Butler, Jane E

    2017-12-01

    During breathing, there is differential activity in the human parasternal intercostal muscles and the activity is tightly coupled to the known mechanical advantages for inspiration of the same regions of muscles. It is not known whether differential activity is preserved for the non-respiratory task of ipsilateral trunk rotation. In the present study, we compared single motor units during resting breathing and axial rotation of the trunk during apnoea. We not only confirmed non-uniform recruitment of motor units across parasternal intercostal muscles in breathing, but also demonstrated that the same motor units show an altered pattern of recruitment in the non-respiratory task of trunk rotation. The output of parasternal intercostal motoneurones is modulated differently across spinal levels depending on the task and these results help us understand the mechanisms that may govern task-dependent differences in motoneurone output. During inspiration, there is differential activity in the human parasternal intercostal muscles across interspaces. We investigated whether the earlier recruitment of motor units in the rostral interspaces compared to more caudal spaces during inspiration is preserved for the non-respiratory task of ipsilateral trunk rotation. Single motor unit activity (SMU) was recorded from the first, second and fourth parasternal interspaces on the right side in five participants in two tasks: resting breathing and 'isometric' axial rotation of the trunk during apnoea. Recruitment of the same SMUs was compared between tasks (n = 123). During resting breathing, differential activity was indicated by earlier recruitment of SMUs in the first and second interspaces compared to the fourth space in inspiration (P motor units showed an altered pattern of recruitment because SMUs in the first interspace were recruited later and at a higher rotation torque than those in the second and fourth interspaces (P recruitment measures, was good-excellent [intraclass

  2. A Systems-Level Approach to Building Sustainable Assessment Cultures: Moderation, Quality Task Design and Dependability of Judgement

    Science.gov (United States)

    Colbert, Peta; Wyatt-Smith, Claire; Klenowski, Val

    2012-01-01

    This article considers the conditions that are necessary at system and local levels for teacher assessment to be valid, reliable and rigorous. With sustainable assessment cultures as a goal, the article examines how education systems can support local-level efforts for quality learning and dependable teacher assessment. This is achieved through…

  3. On the role of trust types and levels on inventory replenishment decision

    OpenAIRE

    Darvish, M.; Kaboli, A.; Cheikhrouhou, N.; Glardon, R.

    2014-01-01

    Using a participatory simulation platform, this paper investigates the inventory replenishment decisions made under different trust categories. Depending on the type of trust (trust in supplier versus trust in customer) and level of trust (high versus low), each decision is categorized and analyzed. We investigate how the inventory manager`s ordering behavior varies regarding their type and level of trust. This study provides evidence for the role of trust in inventory replenishment decision....

  4. Molecular Mechanisms That Underlie the Dynamic Adaptation of Innate Monocyte Memory to Varying Stimulant Strength of TLR Ligands.

    Science.gov (United States)

    Yuan, Ruoxi; Geng, Shuo; Li, Liwu

    2016-01-01

    In adaptation to rising stimulant strength, innate monocytes can be dynamically programed to preferentially express either pro- or anti-inflammatory mediators. Such dynamic innate adaptation or programing may bear profound relevance in host health and disease. However, molecular mechanisms that govern innate adaptation to varying strength of stimulants are not well understood. Using lipopolysaccharide (LPS), the model stimulant of toll-like-receptor 4 (TLR4), we reported that the expressions of pro-inflammatory mediators are preferentially sustained in monocytes adapted by lower doses of LPS, and suppressed/tolerized in monocytes adapted by higher doses of LPS. Mechanistically, monocytes adapted by super-low dose LPS exhibited higher levels of transcription factor, interferon regulatory factor 5 (IRF5), and reduced levels of transcriptional modulator B lymphocyte-induced maturation protein-1 (Blimp-1). Intriguingly, the inflammatory monocyte adaptation by super-low dose LPS is dependent upon TRAM/TRIF but not MyD88. Similar to LPS, we also observed biphasic inflammatory adaptation and tolerance in monocytes challenged with varying dosages of TLR7 agonist. In sharp contrast, rising doses of TLR3 agonist preferentially caused inflammatory adaptation without inducing tolerance. At the molecular level, the differential regulation of IRF5 and Blimp-1 coincides with unique monocyte adaptation dynamics by TLR4/7 and TLR3 agonists. Our study provides novel clue toward the understanding of monocyte adaptation and memory toward distinct TLR ligands.

  5. Molecular mechanisms that underlie the dynamic adaptation of innate monocyte memory to varying stimulant strength of TLR ligands

    Directory of Open Access Journals (Sweden)

    Ruoxi Yuan

    2016-11-01

    Full Text Available In adaptation to rising stimulant strength, innate monocytes can be dynamically programmed to preferentially express either pro- or anti-inflammatory mediators. Such dynamic innate adaptation or programming may bear profound relevance in host health and disease. However, molecular mechanisms that govern innate adaptation to varying strength of stimulants are not well understood. Using lipopolysaccharide (LPS, the model stimulant of Toll-Like-Receptor 4 (TLR4, we reported that the expressions of pro-inflammatory mediators are preferentially sustained in monocytes adapted by lower doses of LPS, and suppressed/tolerized in monocytes adapted by higher doses of LPS. Mechanistically, monocytes adapted by super-low dose LPS exhibited higher levels of transcription factor IRF5 and reduced levels of transcriptional modulator BLIMP-1. Intriguingly, the inflammatory monocyte adaptation by super-low dose LPS is dependent upon TRAM/TRIF but not MyD88. Similar to LPS, we also observed biphasic inflammatory adaptation and tolerance in monocytes challenged with varying dosages of TLR7 agonist. In sharp contrast, rising doses of TLR3 agonist preferentially caused inflammatory adaptation without inducing tolerance. At the molecular level, the differential regulation of IRF5 and Blimp-1 coincides with unique monocyte adaptation dynamics by TLR4/7 and TLR3 agonists. Our study provides novel clue toward the understanding of monocyte adaptation and memory toward distinct TLR ligands.

  6. Student throughput variables and properties: Varying cohort sizes

    Directory of Open Access Journals (Sweden)

    Lucas C.A. Stoop

    2017-11-01

    Full Text Available A recent research paper described how student throughput variables and properties combine to explain the behaviour of stationary or simplified throughput systems. Such behaviour can be understood in terms of the locus of a point in the triangular admissible region of the H-S plane, where H represents headcounts and S successful credits, each depending on the system properties at that point. The efficiency of the student throughput process is given by the ratio S/H. Simplified throughput systems are characterised by stationary graduation and dropout patterns of students as well as by annual intakes of student cohorts of equal size. The effect of varying the size of the annual intakes of student cohorts is reported on here. The observations made lead to the establishment of a more generalised student throughput theory which includes the simplified theory as a special case. The generalised theory still retains the notion of a triangular admissible region in the H-S plane but with the size and shape of the triangle depending on the size of the student cohorts. The ratio S/H again emerges as the process efficiency measure for throughput systems in general with unchanged roles assigned to important system properties. This theory provides for a more fundamental understanding of student throughput systems encountered in real life. Significance: A generalised stationary student throughput theory through varying cohort sizes allows for a far better understanding of real student throughput systems.

  7. Anatomical and Physiological Responses of Citrus Trees to Varying Boron Availability Is Dependent on Rootstock

    Directory of Open Access Journals (Sweden)

    Geisa Lima Mesquita

    2016-03-01

    Full Text Available In Citrus, water, nutrient transport and thereby fruit production, are influenced among other factors, by the interaction between rootstock and boron (B nutrition. This study aimed to investigate how B affects the anatomical structure of roots and leaves as well as leaf gas exchange in sweet orange trees grafted on two contrasting rootstocks in response to B supply. Plants grafted on Swingle citrumelo or Sunki mandarin were grown in a nutrient solution of varying B concentration (deficient, adequate, and excessive. Those grafted on Swingle were more tolerant to both B deficiency and toxicity than those on Sunki, as revealed by higher shoot and root growth. In addition, plants grafted on Sunki exhibited more severe anatomical and physiological damages under B deficiency, showing thickening of xylem cell walls and impairments in whole-plant, leaf-specific hydraulic conductance and leaf CO2 assimilation. Our data revealed that trees grafted on Swingle sustain better growth under low B availablitlity in the root medium and still respond positively to increased B levels by combining higher B absorption and root growth as well as better organization of xylem vessels. Taken together, those traits improved water and B transport to the plant canopy. Under B toxicity, Swingle rootstock would also favor plant growth by reducing anatomical and ultrastructural damage to leaf tissue and improving water transport compared with plants grafted on Sunki. From a practical point of view, our results highlight that B management in citrus orchards shall take into account rootstock varieties, of which the Swingle rootstock was characterized by its performance on regulating anatomical and ultrastructural damages, improving water transport and limiting negative impacts of B stress conditions on plant growth.

  8. Fundamental-frequency and load-varying thermal cycles effects on lifetime estimation of DFIG power converter

    DEFF Research Database (Denmark)

    Zhang, G.; Zhou, D.; Yang, J.

    2017-01-01

    In respect to a Doubly-Fed Induction Generator (DFIG) system, its corresponding time scale varies from microsecond level of power semiconductor switching to second level of the mechanical response. In order to map annual thermal profile of the power semiconductors, different approaches have been ...... adopted to handle the fundamental-frequency thermal cycles and load-varying thermal cycles. Their effects on lifetime estimation of the power device in the Back-to-Back (BTB) power converter are evaluated.......In respect to a Doubly-Fed Induction Generator (DFIG) system, its corresponding time scale varies from microsecond level of power semiconductor switching to second level of the mechanical response. In order to map annual thermal profile of the power semiconductors, different approaches have been...

  9. Local inertial oscillations in the surface ocean generated by time-varying winds

    Science.gov (United States)

    Chen, Shengli; Polton, Jeff A.; Hu, Jianyu; Xing, Jiuxing

    2015-12-01

    A new relationship is presented to give a review study on the evolution of inertial oscillations in the surface ocean locally generated by time-varying wind stress. The inertial oscillation is expressed as the superposition of a previous oscillation and a newly generated oscillation, which depends upon the time-varying wind stress. This relationship is employed to investigate some idealized wind change events. For a wind series varying temporally with different rates, the induced inertial oscillation is dominated by the wind with the greatest variation. The resonant wind, which rotates anti-cyclonically at the local inertial frequency with time, produces maximal amplitude of inertial oscillations, which grows monotonically. For the wind rotating at non-inertial frequencies, the responses vary periodically, with wind injecting inertial energy when it is in phase with the currents, but removing inertial energy when it is out of phase. The wind rotating anti-cyclonically with time is much more favorable to generate inertial oscillations than the cyclonic rotating wind. The wind with a frequency closer to the inertial frequency generates stronger inertial oscillations. For a diurnal wind, the induced inertial oscillation is dependent on latitude and is most significant at 30 °. This relationship is also applied to examine idealized moving cyclones. The inertial oscillation is much stronger on the right-hand side of the cyclone path than on the left-hand side (in the northern hemisphere). This is due to the wind being anti-cyclonic with time on the right-hand side, but cyclonic on the other side. The inertial oscillation varies with the cyclone translation speed. The optimal translation speed generating the greatest inertial oscillations is 2 m/s at the latitude of 10 ° and gradually increases to 6 m/s at the latitude of 30 °.

  10. Multi-Level Anomaly Detection on Time-Varying Graph Data

    Energy Technology Data Exchange (ETDEWEB)

    Bridges, Robert A [ORNL; Collins, John P [ORNL; Ferragut, Erik M [ORNL; Laska, Jason A [ORNL; Sullivan, Blair D [ORNL

    2015-01-01

    This work presents a novel modeling and analysis framework for graph sequences which addresses the challenge of detecting and contextualizing anomalies in labelled, streaming graph data. We introduce a generalization of the BTER model of Seshadhri et al. by adding flexibility to community structure, and use this model to perform multi-scale graph anomaly detection. Specifically, probability models describing coarse subgraphs are built by aggregating probabilities at finer levels, and these closely related hierarchical models simultaneously detect deviations from expectation. This technique provides insight into a graph's structure and internal context that may shed light on a detected event. Additionally, this multi-scale analysis facilitates intuitive visualizations by allowing users to narrow focus from an anomalous graph to particular subgraphs or nodes causing the anomaly. For evaluation, two hierarchical anomaly detectors are tested against a baseline Gaussian method on a series of sampled graphs. We demonstrate that our graph statistics-based approach outperforms both a distribution-based detector and the baseline in a labeled setting with community structure, and it accurately detects anomalies in synthetic and real-world datasets at the node, subgraph, and graph levels. To illustrate the accessibility of information made possible via this technique, the anomaly detector and an associated interactive visualization tool are tested on NCAA football data, where teams and conferences that moved within the league are identified with perfect recall, and precision greater than 0.786.

  11. Study on a technology to afforest water level varying part of a reservoir; Chosuichi suii hendobu ryokuka gijutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Onodera, O.; Matsubara, K.; Koyama, S. [Hokkaido Electric Power Co. Inc., Sapporo (Japan)

    1999-03-19

    Equisetum was noted as a plant adaptable to stringent environment referred to as the water level varying part of a reservoir, and was used for afforestation trials. The afforestation trials were performed at the reservoir of Uryuu Dam No. 1 and the regulating reservoir of Moiwa Dam of Hokkaido Electric Power Company. Although the rate of water level variation is small at Uryuu Dam No. 1, it is necessary for Equisetum to withstand submergence and drought for an extended period of time. Moiwa Dam has high water level variation rate, but its water depth is small, and the reservoir is free of long-term submergence and drought. As a result of long-term observation from 1993 through 1997, Equisetum was found having grown well at lower altitude part with higher submergence frequency. It has grown favorably even in parts where submergence rate reaches about 80%. However, at higher altitude with submergence rate of 10% or lower, decrement trend was seen. At Moiwa Dam, Equisetum was all buried in accumulated sand and earth, revealing that such an environment is unsuitable for Equisetum as the one subject to effect of sand and earth that flow in during freshet. (NEDO)

  12. The Role of Nicotine Dependence in E-Cigarettes' Potential for Smoking Reduction.

    Science.gov (United States)

    Selya, Arielle S; Dierker, Lisa; Rose, Jennifer S; Hedeker, Donald; Mermelstein, Robin J

    2017-07-07

    E-cigarettes (Electronic Nicotine Delivery Systems, or ENDS) are an increasingly popular tobacco product among youth. Some evidence suggests that e-cigarettes may be effective for harm reduction and smoking cessation, although these claims remain controversial. Little is known about how nicotine dependence may contribute to e-cigarettes' effectiveness in reducing or quitting conventional smoking. A cohort of young adults were surveyed over 4 years (approximately ages 19-23). Varying-coefficient models (VCMs) were used to examine the relationship between e-cigarette use and conventional smoking frequency, and how this relationship varies across users with different nicotine dependence levels. Lifetime, but not recent, e-cigarette use was associated with less frequent concurrent smoking of conventional cigarettes among those with high levels of nicotine dependence. However, nondependent e-cigarette users smoked conventional cigarettes slightly more frequently than those who had never used e-cigarettes. Nearly half of ever e-cigarette users reported using them to quit smoking at the last measurement wave. For those who used e-cigarettes in a cessation attempt, the frequency of e-cigarette use was not associated with reductions in future conventional smoking frequency. These findings offer possible support that e-cigarettes may act as a smoking reduction method among highly nicotine-dependent young adult cigarette smokers. However, the opposite was found in non-dependent smokers, suggesting that e-cigarette use should be discouraged among novice tobacco users. Additionally, although a substantial proportion of young adults used e-cigarettes to help them quit smoking, these self-initiated quit attempts with e-cigarettes were not associated with future smoking reduction or cessation. This study offers potential support for e-cigarettes as a smoking reduction tool among highly nicotine-dependent young adult conventional smokers, although the extent and nature of this

  13. Nível sócio-econômico como uma variável geradora de erro em estudos de etnia Socioeconomic level as an error generating variable in racial studies

    Directory of Open Access Journals (Sweden)

    A. D. Passos

    1978-06-01

    Full Text Available Foi estudada a influência do nível sócio-econômico (NSE em variáveis biológicas que apresentam importância em estudos de etnia (peso ao nascer, idade gestacional e número de gestações em 734 crianças normais nascidas em 5 maternidades brasileiras. Os recém-nascidos foram classificados em grupos étnicos de acordo com seus antecedentes raciais. Concluiu-se que o NSE está associado com as variáveis peso ao nascer e número de gestações, funcionando, portanto, como variável geradora de erro em estudos de etnia.The influence of the socio-economic level on biologic variables such as birth-weight, gestational age and birth order was studied in 734 single live-born deliveries at five Brazilian maternities. Live-borns were classified into ethnic groups according to the races of their ancestors. Socio-economic level was found to be associated with birthweight and birth order, acting therefore as an error - generating variable in racial studies.

  14. Attenuation of Morphine Physical Dependence and Blood Levels of Cortisol by Central and Systemic Administration of Ramelteon in Rat

    Directory of Open Access Journals (Sweden)

    Majid Motaghinejad

    2015-05-01

    Full Text Available Background: Chronic administration of morphine cause physical dependence but the exact mechanism of this phenomenon remains unclear. The aim of this study is the assessment of systemic and intracerebroventricular (icv administration of ramelteon (a melatonin receptor agonist on morphine physical dependence. Methods: 88 adult male rats were divided into 2 major groups, namely “systematic” and “central” administration of ramelteon. In the first category, systemic administration of ramelteon at various dosages (10, 20, and 40 mg/kg was assessed on dependent animals and withdrawal signs were compared with positive (received morphine and saline as systemic administration, negative control (saline and group under treatment by ramelteon (40 mg/kg groups. In the second category, central administration of ramelteon at various dosages (25, 50, or 100 μg, was assessed on dependent animals and withdrawal signs were compared with the positive control (received morphine and saline as icv and negative control (saline groups, and the group under treatment by ramelteon (50 μg/5 μl/rat. On the test day, all animals received naloxone (3 mg/kg and were observed for withdrawal signs. Total withdrawal score (TWS was also determined. Finally, to evaluate the stress level of dependent rats, blood cortisols were measured. Results: Central administration of ramelteon in all doses and systemic administration in high doses attenuate withdrawal syndrome in comparison with the dependent positive control group (P<0.05. Both central and systemic administrations of ramelteon can attenuate the blood cortisol level in comparison with the dependent positive control group (P<0.05. Conclusion: In conclusion, we found that central administration of ramelteon attenuated morphine withdrawal symptoms and cortisol level as a stress marker.

  15. Exploring Stress Levels, Job Satisfaction, and Quality of Life in a Sample of Police Officers in Greece

    Directory of Open Access Journals (Sweden)

    Evangelos C. Alexopoulos

    2014-12-01

    Conclusion: Higher levels of stress are related to an increased risk of reporting suboptimal job satisfaction and QoL. The magnitude of these associations varied depending on age, gender, and rank, highlighting the need for stress-management training.

  16. Monoenergetic time-dependent neutron transport in an infinite medium with time-varying cross sections

    International Nuclear Information System (INIS)

    Ganapol, B.D.

    1987-01-01

    For almost 20 yr, the main thrust of the author's research has been the generation of as many benchmark solutions to the time-dependent monoenergetic neutron transport equation as possible. The major motivation behind this effort has been to provide code developers with highly accurate numerical solutions to serve as standards in the assessment of numerical transport algorithms. In addition, these solutions provide excellent educational tools since the important physical features of neutron transport are still present even though the problems solved are idealized. A secondary motivation, though of equal importance, is the intellectual stimulation and understanding provided by the combination of the analytical, numerical, and computational techniques required to obtain these solutions. Therefore, to further the benchmark development, the added complication of time-dependent cross sections in the one-group transport equation is considered here

  17. Understanding the time dependence of atomic level populations in evolving plasmas

    International Nuclear Information System (INIS)

    Judge, Philip G.

    2005-01-01

    The time dependence of atomic level populations in evolving plasmas is studied using an eigenfunction expansion of the non-LTE rate equations. The work aims to develop understanding without the need for, and as an aid to, numerical solutions. The discussion is mostly limited to linear systems, especially those for optically thin plasmas, but the implicitly non-linear case of non-LTE radiative transfer is briefly discussed. Eigenvalue spectra for typical atomic systems are examined using results compiled by Hearon. Diagonal dominance and sign symmetry of rate matrices show that just one eigenvalue is zero (corresponding to the equilibrium state), that the remaining eigenvalues have negative real parts, and that oscillations, if any, are necessarily damped. Gershgorin's theorems are used to show that many eigenvalues are determined by the radiative lifetimes of certain levels, because of diagonal dominance. With other properties, this demonstrates the existence of both 'slow' and 'fast' time-scales, where the 'slow' evolution is controlled by properties of meta-stable levels. It is shown that, when collisions are present, Rydberg states contribute only 'fast' eigenvalues. This justifies use of the quasi-static approximation, in which atoms containing just meta-stable levels can suffice to determine the atomic evolution on time-scales long compared with typical radiative lifetimes. Analytic solutions for two- and three-level atoms are used to examine the basis of earlier intuitive ideas, such as the 'ionizing plasma' approximation. The power and limitations of Gershgorin's theorems are examined through examples taken from the solar atmosphere. The methods should help in the planning and interpretation of both experimental and numerical experiments in which atomic evolution is important. While the examples are astrophysical, the methods and results are applicable to plasmas in general

  18. Scale-dependent behavior of the foredune: Implications for barrier island response to storms and sea-level rise

    Science.gov (United States)

    Houser, Chris; Wernette, Phil; Weymer, Bradley A.

    2018-02-01

    The impact of storm surge on a barrier island tends to be considered from a single cross-shore dimension, dependent on the relative elevations of the storm surge and dune crest. However, the foredune is rarely uniform and can exhibit considerable variation in height and width at a range of length scales. In this study, LiDAR data from barrier islands in Texas and Florida are used to explore how shoreline position and dune morphology vary alongshore, and to determine how this variability is altered or reinforced by storms and post-storm recovery. Wavelet analysis reveals that a power law can approximate historical shoreline change across all scales, but that storm-scale shoreline change ( 10 years) and dune height exhibit similar scale-dependent variations at swash and surf zone scales (< 1000 m). The in-phase nature of the relationship between dune height and storm-scale shoreline change indicates that areas of greater storm-scale shoreline retreat are associated with areas of smaller dunes. It is argued that the decoupling of storm-scale and historical shoreline change at swash and surf zone scales is also associated with the alongshore redistribution of sediment and the tendency of shorelines to evolve to a more diffusive (or straight) pattern with time. The wavelet analysis of the data for post-storm dune recovery is also characterized by red noise at the smallest scales characteristic of diffusive systems, suggesting that it is possible that small-scale variations in dune height can be repaired through alongshore recovery and expansion if there is sufficient time between storms. However, the time required for dune recovery exceeds the time between storms capable of eroding and overwashing the dune. Correlation between historical shoreline retreat and the variance of the dune at swash and surf zone scales suggests that the persistence of the dune is an important control on transgression through island migration or shoreline retreat with relative sea-level rise.

  19. Time varying behaviour of the loudspeaker suspension

    DEFF Research Database (Denmark)

    Agerkvist, Finn; Pedersen, Bo Rohde

    2009-01-01

    The compliance of the loudspeaker suspension is known to depend on the recent excitation level history. Previous investigations have shown that the electrical power as well as displacement and velocity plays a role. In this paper the hypothesis that the changes in compliance are caused mainly...... by how much the suspension has been stretched, i.e., the maximum displacement, is investigated. For this purpose the changes in compliance are measured when exposing the loudspeaker to different levels and types of electrical excitation signals, as well as mechanical excitation only. For sinusoidal...... excitation the change in compliance is shown to depend primarily on maximum displacement. But for square pulse excitation the duration of the excitation also plays an important role....

  20. Threat-level-dependent manipulation of signaled body size: dog growls' indexical cues depend on the different levels of potential danger.

    Science.gov (United States)

    Bálint, Anna; Faragó, Tamás; Miklósi, Ádám; Pongrácz, Péter

    2016-11-01

    Body size is an important feature that affects fighting ability; however, size-related parameters of agonistic vocalizations are difficult to manipulate because of anatomical constraints within the vocal production system. Rare examples of acoustic size modulation are due to specific features that enable the sender to steadily communicate exaggerated body size. However, one could argue that it would be more adaptive if senders could adjust their signaling behavior to the fighting potential of their actual opponent. So far there has been no experimental evidence for this possibility. We tested this hypothesis by exposing family dogs (Canis familiaris) to humans with potentially different fighting ability. In a within-subject experiment, 64 dogs of various breeds consecutively faced two threateningly approaching humans, either two men or two women of different stature, or a man and a woman of similar or different stature. We found that the dogs' vocal responses were affected by the gender of the threatening stranger and the dog owner's gender. Dogs with a female owner, or those dogs which came from a household where both genders were present, reacted with growls of lower values of the Pitch-Formant component (including deeper fundamental frequency and lower formant dispersion) to threatening men. Our results are the first to show that non-human animals react with dynamic alteration of acoustic parameters related to their individual indexical features (body size), depending on the level of threat in an agonistic encounter.

  1. Radionuclide content of wastewater and solid waste from a low-level effluent treatment plant

    International Nuclear Information System (INIS)

    Muhamat Omar; Zalina Laili; Nik Marzukee Nik Ibrahim; Mat Bakar Mahusin

    2010-01-01

    A study on radioactivity levels of wastewater and solid waste from a Low-level Effluent Treatment Plant has been carried out. The measurement of radionuclide concentration was carried out using gamma spectrometry. Natural and anthropogenic radionuclides were detected in solid radioactive waste recovered from the treatment plant. The presence of radionuclides in waste water varies depending on activities carried out in laboratories and facilities connected to the plant. (author)

  2. Interaural Level Difference Dependent Gain Control and Synaptic Scaling Underlying Binaural Computation

    Science.gov (United States)

    Xiong, Xiaorui R.; Liang, Feixue; Li, Haifu; Mesik, Lukas; Zhang, Ke K.; Polley, Daniel B.; Tao, Huizhong W.; Xiao, Zhongju; Zhang, Li I.

    2013-01-01

    Binaural integration in the central nucleus of inferior colliculus (ICC) plays a critical role in sound localization. However, its arithmetic nature and underlying synaptic mechanisms remain unclear. Here, we showed in mouse ICC neurons that the contralateral dominance is created by a “push-pull”-like mechanism, with contralaterally dominant excitation and more bilaterally balanced inhibition. Importantly, binaural spiking response is generated apparently from an ipsilaterally-mediated scaling of contralateral response, leaving frequency tuning unchanged. This scaling effect is attributed to a divisive attenuation of contralaterally-evoked synaptic excitation onto ICC neurons with their inhibition largely unaffected. Thus, a gain control mediates the linear transformation from monaural to binaural spike responses. The gain value is modulated by interaural level difference (ILD) primarily through scaling excitation to different levels. The ILD-dependent synaptic scaling and gain adjustment allow ICC neurons to dynamically encode interaural sound localization cues while maintaining an invariant representation of other independent sound attributes. PMID:23972599

  3. Frequency variations of gravity waves interacting with a time-varying tide

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.M.; Zhang, S.D.; Yi, F.; Huang, K.M.; Gan, Q.; Gong, Y. [Wuhan Univ., Hubei (China). School of Electronic Information; Ministry of Education, Wuhan, Hubei (China). Key Lab. of Geospace Environment and Geodesy; State Observatory for Atmospheric Remote Sensing, Wuhan, Hubei (China); Zhang, Y.H. [Nanjing Univ. of Information Science and Technology (China). College of Hydrometeorolgy

    2013-11-01

    Using a nonlinear, 2-D time-dependent numerical model, we simulate the propagation of gravity waves (GWs) in a time-varying tide. Our simulations show that when aGW packet propagates in a time-varying tidal-wind environment, not only its intrinsic frequency but also its ground-based frequency would change significantly. The tidal horizontal-wind acceleration dominates the GW frequency variation. Positive (negative) accelerations induce frequency increases (decreases) with time. More interestingly, tidal-wind acceleration near the critical layers always causes the GW frequency to increase, which may partially explain the observations that high-frequency GW components are more dominant in the middle and upper atmosphere than in the lower atmosphere. The combination of the increased ground-based frequency of propagating GWs in a time-varying tidal-wind field and the transient nature of the critical layer induced by a time-varying tidal zonal wind creates favorable conditions for GWs to penetrate their originally expected critical layers. Consequently, GWs have an impact on the background atmosphere at much higher altitudes than expected, which indicates that the dynamical effects of tidal-GW interactions are more complicated than usually taken into account by GW parameterizations in global models.

  4. Tail dependence between oil and stocks of major oil-exporting countries using the CoVaR approach

    Directory of Open Access Journals (Sweden)

    Nader Trabelsi

    2017-12-01

    Full Text Available This paper investigates the negative tail risk dependence between oil shocks and stock indices (at aggregated and desegregated levels for Saudi Arabia (KSA, United Arab Emirates (UAE and Russia, over the period between 2007 and 2016. DCC-MGARCH approach and CoVaR measure are employed to assess the oil shock exposure. The results show that the tail dependence is significant and depends on the origin of the oil shocks, with intensity that varies across countries and sectors. Keywords: Oil price shocks, Oil-exporting countries, Conditional VaR, JEL Classification: C58, G11, Q4

  5. Hyperglycaemia-induced impairment of endothelium-dependent vasorelaxation in rat mesenteric arteries is mediated by intracellular methylglyoxal levels in a pathway dependent on oxidative stress

    DEFF Research Database (Denmark)

    Brouwers, O; Niessen, P M; Haenen, G

    2010-01-01

    -hydro-5-methylimidazolone (MG-H1) was detected with an antibody against MG-H1 and quantified with ultra-performance liquid chromatography (tandem) mass spectrometry. Reactive oxygen species formation was measured with a 5-(and-6)-chloromethyl-2'7'-dichlorodihydrofluorescein diacetate acetyl ester probe...... for AGE ligand S100b did (p cells and adventitia by fivefold accompanied by an eightfold increase in the oxidative stress marker nitrotyrosine. Antioxidant pre-incubation prevented methylglyoxal......-induced impairment of vasoreactivity. CONCLUSIONS/INTERPRETATION: These data show that hyperglycaemia-induced impairment of endothelium-dependent vasorelaxation is mediated by increased intracellular methylglyoxal levels in a pathway dependent on oxidative stress....

  6. Noisy time-dependent spectra

    International Nuclear Information System (INIS)

    Shore, B.W.; Eberly, J.H.

    1983-01-01

    The definition of a time-dependent spectrum registered by an idealized spectrometer responding to a time-varying electromagnetic field as proposed by Eberly and Wodkiewicz and subsequently applied to the spectrum of laser-induced fluorescence by Eberly, Kunasz, and Wodkiewicz is here extended to allow a stochastically fluctuating (interruption model) environment: we provide an algorithm for numerical determination of the time-dependent fluorescence spectrum of an atom subject to excitation by an intense noisy laser and interruptive relaxation

  7. Tuning of Human Modulation Filters Is Carrier-Frequency Dependent

    Science.gov (United States)

    Simpson, Andrew J. R.; Reiss, Joshua D.; McAlpine, David

    2013-01-01

    Recent studies employing speech stimuli to investigate ‘cocktail-party’ listening have focused on entrainment of cortical activity to modulations at syllabic (5 Hz) and phonemic (20 Hz) rates. The data suggest that cortical modulation filters (CMFs) are dependent on the sound-frequency channel in which modulations are conveyed, potentially underpinning a strategy for separating speech from background noise. Here, we characterize modulation filters in human listeners using a novel behavioral method. Within an ‘inverted’ adaptive forced-choice increment detection task, listening level was varied whilst contrast was held constant for ramped increments with effective modulation rates between 0.5 and 33 Hz. Our data suggest that modulation filters are tonotopically organized (i.e., vary along the primary, frequency-organized, dimension). This suggests that the human auditory system is optimized to track rapid (phonemic) modulations at high sound-frequencies and slow (prosodic/syllabic) modulations at low frequencies. PMID:24009759

  8. Epidemic spreading in time-varying community networks

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Guangming, E-mail: wangxy@dlut.edu.cn, E-mail: ren-guang-ming@163.com [School of Electronic and Information, Guangdong Polytechnic Normal University, Guangzhou 510665 (China); Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, Xingyuan, E-mail: wangxy@dlut.edu.cn, E-mail: ren-guang-ming@163.com [Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China)

    2014-06-15

    The spreading processes of many infectious diseases have comparable time scale as the network evolution. Here, we present a simple networks model with time-varying community structure, and investigate susceptible-infected-susceptible epidemic spreading processes in this model. By both theoretic analysis and numerical simulations, we show that the efficiency of epidemic spreading in this model depends intensively on the mobility rate q of the individuals among communities. We also find that there exists a mobility rate threshold q{sub c}. The epidemic will survive when q > q{sub c} and die when q < q{sub c}. These results can help understanding the impacts of human travel on the epidemic spreading in complex networks with community structure.

  9. Epidemic spreading in time-varying community networks

    International Nuclear Information System (INIS)

    Ren, Guangming; Wang, Xingyuan

    2014-01-01

    The spreading processes of many infectious diseases have comparable time scale as the network evolution. Here, we present a simple networks model with time-varying community structure, and investigate susceptible-infected-susceptible epidemic spreading processes in this model. By both theoretic analysis and numerical simulations, we show that the efficiency of epidemic spreading in this model depends intensively on the mobility rate q of the individuals among communities. We also find that there exists a mobility rate threshold q c . The epidemic will survive when q > q c and die when q  c . These results can help understanding the impacts of human travel on the epidemic spreading in complex networks with community structure

  10. Edge Modeling by Two Blur Parameters in Varying Contrasts.

    Science.gov (United States)

    Seo, Suyoung

    2018-06-01

    This paper presents a method of modeling edge profiles with two blur parameters, and estimating and predicting those edge parameters with varying brightness combinations and camera-to-object distances (COD). First, the validity of the edge model is proven mathematically. Then, it is proven experimentally with edges from a set of images captured for specifically designed target sheets and with edges from natural images. Estimation of the two blur parameters for each observed edge profile is performed with a brute-force method to find parameters that produce global minimum errors. Then, using the estimated blur parameters, actual blur parameters of edges with arbitrary brightness combinations are predicted using a surface interpolation method (i.e., kriging). The predicted surfaces show that the two blur parameters of the proposed edge model depend on both dark-side edge brightness and light-side edge brightness following a certain global trend. This is similar across varying CODs. The proposed edge model is compared with a one-blur parameter edge model using experiments of the root mean squared error for fitting the edge models to each observed edge profile. The comparison results suggest that the proposed edge model has superiority over the one-blur parameter edge model in most cases where edges have varying brightness combinations.

  11. Exploring Secondary Students' Epistemological Features Depending on the Evaluation Levels of the Group Model on Blood Circulation

    Science.gov (United States)

    Lee, Shinyoung; Kim, Heui-Baik

    2014-01-01

    The purpose of this study is to identify the epistemological features and model qualities depending on model evaluation levels and to explore the reasoning process behind high-level evaluation through small group interaction about blood circulation. Nine groups of three to four students in the eighth grade participated in the modeling practice.…

  12. The influence of message framing, intention to quit smoking, and nicotine dependence on the persuasiveness of smoking cessation messages.

    Science.gov (United States)

    Moorman, Marjolein; van den Putte, Bas

    2008-10-01

    This study explores the combined effect of message framing, intention to quit smoking, and nicotine dependence on the persuasiveness of smoking cessation messages. Pre- and post-message measures of quit intention, attitude toward smoking cessation, and perceived behavioral control were taken in two separate waves from current cigarette smokers with varying levels of nicotine dependence (N=151). In the second wave, participants were randomly assigned to one of two groups. In the first group, participants read a smoking cessation message which emphasized the benefits of quitting (positive frame). In the second group participants read a message which emphasized the costs of not quitting (negative frame). Results show that smokers' intentions to quit smoking and their level of nicotine dependence jointly influence the persuasiveness of positive and negative message frames. When nicotine dependence and quitting intention are both high, a negative frame works best. Conversely, a positive frame is preferable when nicotine dependence or quitting intention is low. Smokers' level of processing is proposed as the underlying mechanism explaining the different effects of message frames.

  13. A Quasi-Feed-In-Tariff policy formulation in micro-grids: A bi-level multi-period approach

    International Nuclear Information System (INIS)

    Taha, Ahmad F.; Hachem, Nadim A.; Panchal, Jitesh H.

    2014-01-01

    A Quasi-Feed-In-Tariff (QFIT) policy formulation is presented for micro-grids that integrates renewable energy generation considering Policy Makers' and Generation Companies' (GENCOs) objectives assuming a bi-level multi-period formulation that integrates physical characteristics of the power-grid. The upper-level problem corresponds to the PM, whereas the lower-level decisions are made by GENCOs. We consider that some GENCOs are green energy producers, while others are black energy producers. Policy makers incentivize green energy producers to generate energy through the payment of optimal time-varying subsidy price. The policy maker's main objective is to maximize an overall social welfare that includes factors such as demand surplus, energy cost, renewable energy subsidy price, and environmental standards. The lower-level problem corresponding to the GENCOs is based on maximizing the players' profits. The proposed QFIT policy differs from the FIT policy in the sense that the subsidy price-based contracts offered to green energy producers dynamically change over time, depending on the physical properties of the grid, demand, and energy price fluctuations. The integrated problem solves for time-varying subsidy price and equilibrium energy quantities that optimize the system welfare under different grid and system conditions. - Highlights: • We present a bi-level optimization problem formulation for Quasi-Feed-In-Tariff (QFIT) policy. • QFIT dictates that subsidy prices dynamically vary over time depending on conditions. • Power grid's physical characteristics affect optimal subsidy prices and energy generation. • To maximize welfare, policy makers ought to increase subsidy prices during the peak-load

  14. Extreme Unconditional Dependence Vs. Multivariate GARCH Effect in the Analysis of Dependence Between High Losses on Polish and German Stock Indexes

    Science.gov (United States)

    Rokita, Pawel

    Classical portfolio diversification methods do not take account of any dependence between extreme returns (losses). Many researchers provide, however, some empirical evidence for various assets that extreme-losses co-occur. If the co-occurrence is frequent enough to be statistically significant, it may seriously influence portfolio risk. Such effects may result from a few different properties of financial time series, like for instance: (1) extreme dependence in a (long-term) unconditional distribution, (2) extreme dependence in subsequent conditional distributions, (3) time-varying conditional covariance, (4) time-varying (long-term) unconditional covariance, (5) market contagion. Moreover, a mix of these properties may be present in return time series. Modeling each of them requires different approaches. It seams reasonable to investigate whether distinguishing between the properties is highly significant for portfolio risk measurement. If it is, identifying the effect responsible for high loss co-occurrence would be of a great importance. If it is not, the best solution would be selecting the easiest-to-apply model. This article concentrates on two of the aforementioned properties: extreme dependence (in a long-term unconditional distribution) and time-varying conditional covariance.

  15. The Effects of Text Density Levels and the Cognitive Style of Field Dependence on Learning from a CBI Tutorial

    Science.gov (United States)

    Ipek, Ismail

    2011-01-01

    The purpose of this study was to investigate the effects of variations in text density levels and the cognitive style of field dependence on learning from a CBI tutorial, based on the dependent measures of achievement, reading comprehension, and reading rate, and of lesson completion time. Eighty college undergraduate students were randomly…

  16. Motion-dependent levels of order in a relativistic universe.

    Science.gov (United States)

    Frieden, B Roy; Petri, Michael

    2012-09-01

    Consider a generally closed system of continuous three-space coordinates x with a differentiable amplitude function ψ(x). What is its level of order R? Define R by the property that it decreases (or stays constant) after the system is coarse grained. Then R turns out to obey R=8(-1)L(2)I,where quantity I=4∫dx[nabla]ψ(*)·[nabla]ψ is the classical Fisher information in the system and L is the longest chord that can connect two points on the system surface. In general, order R is (i) unitless, and (ii) invariant to uniform stretch or compression of the system. On this basis, the order R in the Universe was previously found to be invariant in time despite its Hubble expansion, and with value R=26.0×10(60) for flat space. By comparison, here we model the Universe as a string-based "holostar," with amplitude function ψ(x)[proportionality]1/r over radial interval r=(r(0),r(H)). Here r(0) is of order the Planck length and r(H) is the radial extension of the holostar, estimated as the known value of the Hubble radius. Curvature of space and relative motion of the observer must now be taken into account. It results that a stationary observer observes a level of order R=(8/9)(r(H)/r(0))(3/2)=0.42×10(90); while for a free-falling observer R=2(-1)(r(H)/r(0))(2)=0.85×10(120). Both order values greatly exceed the above flat-space value. Interestingly, they are purely geometric measures, depending solely upon ratio r(H)/r(0). Remarkably, the free-fall value ~10(120) of R approximates the negentropy of a universe modeled as discrete. This might mean that the Universe contains about equal amounts of continuous and discrete structure.

  17. Time-Varying Value of Energy Efficiency in Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Mims, Natalie; Eckman, Tom; Schwartz, Lisa C.

    2018-04-02

    Quantifying the time-varying value of energy efficiency is necessary to properly account for all of its benefits and costs and to identify and implement efficiency resources that contribute to a low-cost, reliable electric system. Historically, most quantification of the benefits of efficiency has focused largely on the economic value of annual energy reduction. Due to the lack of statistically representative metered end-use load shape data in Michigan (i.e., the hourly or seasonal timing of electricity savings), the ability to confidently characterize the time-varying value of energy efficiency savings in the state, especially for weather-sensitive measures such as central air conditioning, is limited. Still, electric utilities in Michigan can take advantage of opportunities to incorporate the time-varying value of efficiency into their planning. For example, end-use load research and hourly valuation of efficiency savings can be used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service (KEMA 2012). In addition, accurately calculating the time-varying value of efficiency may help energy efficiency program administrators prioritize existing offerings, set incentive or rebate levels that reflect the full value of efficiency, and design new programs.

  18. Sheep response to sugar cane tops supplemented with varying ...

    African Journals Online (AJOL)

    Twenty WAD sheep averaging 10.14kg were randomly divided into four groups of 5 replicates, and each group was fed sugarcane tops (SCT) supplemented with varying levels (0%, 25%, 50 and 75%) of Leucaena leucocephala foliage (LLF) in a completely randomized design. Results showed that sugarcane tops (SCT) ...

  19. The Kinematics and Spondylosis of the Lumbar Spine Vary Depending on the Levels of Motion Segments in Individuals With Low Back Pain.

    Science.gov (United States)

    Basques, Bryce A; Espinoza Orías, Alejandro A; Shifflett, Grant D; Fice, Michael P; Andersson, Gunnar B; An, Howard S; Inoue, Nozomu

    2017-07-01

    A prospective cohort study. The aim of this study was to identify associations of spondylotic and kinematic changes with low back pain (LBP). The ability to characterize and differentiate the biomechanics of both the symptomatic and asymptomatic lumbar spine is crucial to alleviate the sparse literature on the association of lumbar spine biomechanics and LBP. Lumbar dynamic plain radiographs (flexion-extension), dynamic computed tomography (CT) scanning (axial rotation, disc height), and magnetic resonance imaging (MRI, disc and facet degeneration grades) were obtained for each subject. These parameters were compared between symptomatic and control groups using Student t test and multivariate logistic regression, which controlled for patient age and sex and identified spinal parameters that were independently associated with symptomatic LBP. Disc grade and mean segmental motion by level were tested by one-way analysis of variance (ANOVA). Ninety-nine volunteers (64 asymptomatic/35 LBP) were prospectively recruited. Mean age was 37.3 ± 10.1 years and 55% were male. LBP showed association with increased L5/S1 translation [odds ratio (OR) 1.63 per mm, P = 0.005], decreased flexion-extension motion at L1/L2 (OR 0.87 per degree, P = 0.036), L2/L3 (OR 0.88 per degree, P = 0.036), and L4/L5 (OR 0.87 per degree, P = 0.020), increased axial rotation at L4/L5 (OR 2.11 per degree, P = 0.032), decreased disc height at L3/L4 (OR 0.52 per mm, P = 0.008) and L4/L5 (OR 0.37 per mm, p  0.05). In symptomatic individuals, L4/L5 and L5/S1 levels were affected by spondylosis and kinematic changes. This study clarifies the relationships between kinematic alterations and LBP, mostly observed at the above-mentioned segments. N/A.

  20. Combined risk assessment of nonstationary monthly water quality based on Markov chain and time-varying copula.

    Science.gov (United States)

    Shi, Wei; Xia, Jun

    2017-02-01

    Water quality risk management is a global hot research linkage with the sustainable water resource development. Ammonium nitrogen (NH 3 -N) and permanganate index (COD Mn ) as the focus indicators in Huai River Basin, are selected to reveal their joint transition laws based on Markov theory. The time-varying moments model with either time or land cover index as explanatory variables is applied to build the time-varying marginal distributions of water quality time series. Time-varying copula model, which takes the non-stationarity in the marginal distribution and/or the time variation in dependence structure between water quality series into consideration, is constructed to describe a bivariate frequency analysis for NH 3 -N and COD Mn series at the same monitoring gauge. The larger first-order Markov joint transition probability indicates water quality state Class V w , Class IV and Class III will occur easily in the water body of Bengbu Sluice. Both marginal distribution and copula models are nonstationary, and the explanatory variable time yields better performance than land cover index in describing the non-stationarities in the marginal distributions. In modelling the dependence structure changes, time-varying copula has a better fitting performance than the copula with the constant or the time-trend dependence parameter. The largest synchronous encounter risk probability of NH 3 -N and COD Mn simultaneously reaching Class V is 50.61%, while the asynchronous encounter risk probability is largest when NH 3 -N and COD Mn is inferior to class V and class IV water quality standards, respectively.

  1. Temperature dependence of the chromium(III) R1 linewidth in emerald

    Science.gov (United States)

    Carceller-Pastor, Ivana; Hutchison, Wayne D.; Riesen, Hans

    2013-03-01

    The temperature dependent contribution to the R1 (2E ← 4A2) linewidth in emerald, Be3Al2Si6O18:Cr3, has been measured by employing spectral hole-burning, fluorescence line narrowing and conventional luminescence experiments. The contribution varies from 0.6 MHz at 6.5 K to ˜420 GHz at 240 K and the line red-shifts by ˜570 GHz. Above 60 K, the dependence is well described by a non-perturbative formalism for two-phonon Raman scattering. Below this temperature the direct one-phonon process between the levels of the split 2E excited state dominates. However, it appears that a localized low-energy phonon leads to a deviation from the standard pattern at lowest temperatures.

  2. Dependence of critical current properties on growth temperature and doping level of nanorods in PLD-YBa2Cu3Oy films

    International Nuclear Information System (INIS)

    Fujita, N.; Haruta, M.; Ichinose, A.; Maeda, T.; Horii, S.

    2013-01-01

    Highlights: •We fabricated Y123 films with Ba–Nb–O nanorods at various growth temperatures. •Irreversibility lines depended on growth temperature and doping level of Ba–Nb–O. •Nanorod morphology was drastically changed by growth temperature (T s ). •Its T s dependence of the matching field was different from that for Er123 + Ba–Nb–O. -- Abstract: The vortex-Bose-glass-like irreversibility lines (ILs) emerged for 2.5 and 5.0 at.% Ba–Nb–O (BNO)-doped YBa 2 Cu 3 O y films deposited by PLD using Nd:YAG-laser. The ILs strongly depended on growth temperature (T s ) in addition to the doping level of BNO. The vortex glass region was expanded with increasing T s or doping level of BNO. Drastic change of the nanorod morphology from short and bended nanorods to long and linear nanorods with increasing T s was clarified. Moreover, it was found that T s -dependent ILs were quite different from our previous results in BNO-doped ErBa 2 Cu 3 O y films

  3. Octopamine regulates antennal sensory neurons via daytime-dependent changes in cAMP and IP3 levels in the hawkmoth Manduca sexta.

    Directory of Open Access Journals (Sweden)

    Thomas Schendzielorz

    Full Text Available The biogenic amine octopamine (OA mediates reward signals in olfactory learning and memory as well as circadian rhythms of sleep and activity. In the crepuscular hawkmoth Manduca sexta, OA changed pheromone detection thresholds daytime-dependently, suggesting that OA confers circadian control of olfactory transduction. Thus, with enzyme-linked immunosorbent assays we searched hawkmoth antennae for daytime-dependent changes in the concentration of OA and its respective second messengers. Antennal stimulation with OA raised cAMP- and IP3 levels. Furthermore, antennae expressed daytime-dependent changes in the concentration of OA, with maxima at Zeitgebertime (ZT 20 when moths were active and also maximal concentrations of cAMP occurred. Maximal IP3 levels at ZT 18 and 23 correlated with maximal flight activity of male moths, while minimal IP3 levels at dusk correlated with peaks of feeding activity. Half maximal effective concentration (EC50 for activation of the OA-receptor decreased during the moth's activity phase suggesting daytime-dependent changes in OA receptor sensitivity. With an antiserum against tyramine, the precursor of OA, two centrifugal neurons were detected projecting out into the sensory cell layer of the antenna, possibly mediating more rapid stimulus-dependent OA actions. Indeed, in fast kinetic assays OA receptor stimulation increased cAMP concentrations within 50 msec. Thus, we hypothesize that fast, stimulus-dependent centrifugal control of OA-release in the antenna occurs. Additional slow systemic OA actions might be based upon circadian release of OA into the hemolymph mediating circadian rhythms of antennal second messenger levels. The resulting rhythms of odor sensitivity are suggested to underlie circadian rhythms in odor-mediated behavior.

  4. Time Varying Behavior of the Loudspeaker Suspension

    DEFF Research Database (Denmark)

    Pedersen, Bo Rohde; Agerkvist, Finn T.

    2007-01-01

    The suspension part of the electrodynamic loudspeaker is often modelled as a simple linear spring with viscous damping, however the dynamic behaviour of the suspension is much more complicated than predicted by such a simple model. At higher levels the compliance becomes non-linear and often chan...... changes during excitation at high levels. This paper investigates how the compliance of the suspension depends on the excitation, i.e. level and frequency content. The measurements are compared with other known measurement methods of the suspension....

  5. Performance and cost implication of finisher turkeys fed varying ...

    African Journals Online (AJOL)

    A 28-day experiment was conducted to determine the effect of feeding varying levels of rice milling waste as a substitute on maize on the performance, nutrient utilization and the economics implication on finisher turkeys. Five turkey finisher diets were formulated by substituting maize with rice milling waste at 0%, 25%, 50%, ...

  6. A varying-coefficient method for analyzing longitudinal clinical trials data with nonignorable dropout

    Science.gov (United States)

    Forster, Jeri E.; MaWhinney, Samantha; Ball, Erika L.; Fairclough, Diane

    2011-01-01

    Dropout is common in longitudinal clinical trials and when the probability of dropout depends on unobserved outcomes even after conditioning on available data, it is considered missing not at random and therefore nonignorable. To address this problem, mixture models can be used to account for the relationship between a longitudinal outcome and dropout. We propose a Natural Spline Varying-coefficient mixture model (NSV), which is a straightforward extension of the parametric Conditional Linear Model (CLM). We assume that the outcome follows a varying-coefficient model conditional on a continuous dropout distribution. Natural cubic B-splines are used to allow the regression coefficients to semiparametrically depend on dropout and inference is therefore more robust. Additionally, this method is computationally stable and relatively simple to implement. We conduct simulation studies to evaluate performance and compare methodologies in settings where the longitudinal trajectories are linear and dropout time is observed for all individuals. Performance is assessed under conditions where model assumptions are both met and violated. In addition, we compare the NSV to the CLM and a standard random-effects model using an HIV/AIDS clinical trial with probable nonignorable dropout. The simulation studies suggest that the NSV is an improvement over the CLM when dropout has a nonlinear dependence on the outcome. PMID:22101223

  7. Phantom dark energy with varying-mass dark matter particles: Acceleration and cosmic coincidence problem

    International Nuclear Information System (INIS)

    Leon, Genly; Saridakis, Emmanuel N.

    2010-01-01

    We investigate several varying-mass dark matter particle models in the framework of phantom cosmology. We examine whether there exist late-time cosmological solutions, corresponding to an accelerating universe and possessing dark energy and dark matter densities of the same order. Imposing exponential or power-law potentials and exponential or power-law mass dependence, we conclude that the coincidence problem cannot be solved or even alleviated. Thus, if dark energy is attributed to the phantom paradigm, varying-mass dark matter models cannot fulfill the basic requirement that led to their construction.

  8. Finite-Time Stability of Large-Scale Systems with Interval Time-Varying Delay in Interconnection

    Directory of Open Access Journals (Sweden)

    T. La-inchua

    2017-01-01

    Full Text Available We investigate finite-time stability of a class of nonlinear large-scale systems with interval time-varying delays in interconnection. Time-delay functions are continuous but not necessarily differentiable. Based on Lyapunov stability theory and new integral bounding technique, finite-time stability of large-scale systems with interval time-varying delays in interconnection is derived. The finite-time stability criteria are delays-dependent and are given in terms of linear matrix inequalities which can be solved by various available algorithms. Numerical examples are given to illustrate effectiveness of the proposed method.

  9. Density-dependent seedling mortality varies with light availability and species abundance in wet and dry Hawaiian forests

    Science.gov (United States)

    Faith Inman-Narahari; Rebecca Ostertag; Stephen P. Hubbell; Christian P. Giardina; Susan Cordell; Lawren Sack; Andrew MacDougall

    2016-01-01

    Conspecific density may contribute to patterns of species assembly through negative density dependence (NDD) as predicted by the Janzen-Connell hypothesis, or through facilitation (positive density dependence; PDD). Conspecific density effects are expected to be more negative in darker and wetter environments due to higher pathogen abundance and...

  10. Dengue-Immune Humans Have Higher Levels of Complement-Independent Enhancing Antibody than Complement-Dependent Neutralizing Antibody.

    Science.gov (United States)

    Yamanaka, Atsushi; Konishi, Eiji

    2017-09-25

    Dengue is the most important arboviral disease worldwide. We previously reported that most inhabitants of dengue-endemic countries who are naturally immune to the disease have infection-enhancing antibodies whose in vitro activity does not decrease in the presence of complement (complement-independent enhancing antibodies, or CiEAb). Here, we compared levels of CiEAb and complement-dependent neutralizing antibodies (CdNAb) in dengue-immune humans. A typical antibody dose-response pattern obtained in our assay system to measure the balance between neutralizing and enhancing antibodies showed both neutralizing and enhancing activities depending on serum dilution factor. The addition of complement to the assay system increased the activity of neutralizing antibodies at lower dilutions, indicating the presence of CdNAb. In contrast, similar dose-response curves were obtained with and without complement at higher dilutions, indicating higher levels of CiEAb than CdNAb. For experimental support for the higher CiEAb levels, a cocktail of mouse monoclonal antibodies against dengue virus type 1 was prepared. The antibody dose-response curves obtained in this assay, with or without complement, were similar to those obtained with human serum samples when a high proportion of D1-V-3H12 (an antibody exhibiting only enhancing activity and thus a model for CiEAb) was used in the cocktail. This study revealed higher-level induction of CiEAb than CdNAb in humans naturally infected with dengue viruses.

  11. Relationship between systemic hemodynamics and ambulatory blood pressure level are sex dependent.

    Science.gov (United States)

    Alfie, J; Waisman, G D; Galarza, C R; Magi, M I; Vasvari, F; Mayorga, L M; Cámera, M I

    1995-12-01

    Sex-related differences in systemic hemodynamics were analyzed by means of cardiac index and systemic vascular resistance according to the level of daytime ambulatory blood pressure. In addition, we assessed the relations between ambulatory blood pressure measurements and systemic hemodynamics in male and female patients. We prospectively included 52 women and 53 men referred to our unit for evaluation of arterial hypertension. Women and men were grouped according to the level of daytime mean arterial pressure: or = 110 mm Hg. Patients underwent noninvasive evaluation of resting hemodynamics (impedance cardiography) and 24-hour ambulatory blood pressure monitoring. Compared with women men with lower daytime blood pressure had a 12% higher systemic vascular resistance index (P = NS) and a 14% lower cardiac index (P < .02), whereas men with higher daytime blood pressure had a 25% higher vascular resistance (P < .003) and a 21% lower cardiac index (P < .0004). Furthermore, in men systemic vascular resistance correlated positively with both daytime and nighttime systolic and diastolic blood pressures, whereas cardiac index correlated negatively only with daytime diastolic blood pressure. In contrast, women did not exhibit any significant correlation between hemodynamic parameters and ambulatory blood pressure measurements. In conclusion, sex-related differences in systemic hemodynamics were more pronounced in the group with higher daytime hypertension. The relations between systemic hemodynamics and ambulatory blood pressure level depended on the sex of the patient. In men a progressive circulatory impairment underlies the increasing level of ambulatory blood pressure, but this was not observed in women.

  12. Association Between Variants in Arsenic (+3 Oxidation State) Methyltranserase (AS3MT) and Urinary Metabolites of Inorganic Arsenic: Role of Exposure Level

    Science.gov (United States)

    Xu, Xiaofan; Drobná, Zuzana; Voruganti, V. Saroja; Barron, Keri; González-Horta, Carmen; Sánchez-Ramírez, Blanca; Ballinas-Casarrubias, Lourdes; Cerón, Roberto Hernández; Morales, Damián Viniegra; Terrazas, Francisco A. Baeza; Ishida, María C.; Gutiérrez-Torres, Daniela S.; Saunders, R. Jesse; Crandell, Jamie; Fry, Rebecca C.; Loomis, Dana; García-Vargas, Gonzalo G.; Del Razo, Luz M.; Stýblo, Miroslav; Mendez, Michelle A.

    2016-01-01

    Abstract Variants in AS3MT, the gene encoding arsenic (+3 oxidation state) methyltranserase, have been shown to influence patterns of inorganic arsenic (iAs) metabolism. Several studies have suggested that capacity to metabolize iAs may vary depending on levels of iAs exposure. However, it is not known whether the influence of variants in AS3MT on iAs metabolism also vary by level of exposure. We investigated, in a population of Mexican adults exposed to drinking water As, whether associations between 7 candidate variants in AS3MT and urinary iAs metabolites were consistent with prior studies, and whether these associations varied depending on the level of exposure. Overall, associations between urinary iAs metabolites and AS3MT variants were consistent with the literature. Referent genotypes, defined as the genotype previously associated with a higher percentage of urinary dimethylated As (DMAs%), were associated with significant increases in the DMAs% and ratio of DMAs to monomethylated As (MAs), and significant reductions in MAs% and iAs%. For 3 variants, associations between genotypes and iAs metabolism were significantly stronger among subjects exposed to water As >50 versus ≤50 ppb (water As X genotype interaction P iAs exposure may influence the extent to which several AS3MT variants affect iAs metabolism. The variants most strongly associated with iAs metabolism—and perhaps with susceptibility to iAs-associated disease—may vary in settings with exposure level. PMID:27370415

  13. Determination of dependence of feed intake level on functional and technological parameters of prescription mixture

    Directory of Open Access Journals (Sweden)

    Aksenova O. I.

    2016-12-01

    Full Text Available The problem of the development of pet food formulations in the conditions of information uncertainty which is characteristic of an actual business enterprise engaged in production of feed has been considered in the paper. The analysis of the literature [1–4] has shown that the main works are devoted to the extrusion of plastics and cereal products, with the temperature conditions equal to 130–200 ºC. This temperature range is not suitable for the production of pet food, and researches on this issue are virtually absent. This study is devoted to defining the functional and technological parameters of prescription mixture depending on the level of feed intake by unproductive animals; this knowledge will allow manufacturers to simplify the development of new formulations of balanced feed. Identification of this relationship has been carried out on the basis of modeling methods of mathematical statistics in Excel and Mathcad packages, as well as on the basis of fuzzy logic set theory in MatLAB package, as the construction of a complete mathematical model is complicated by absence of an explicit numerical form of the result received on the basis of sensory analysis. The research has revealed the dependence of feed intake level on functional and technological parameters of prescription mix for non-productive animals, in particular, the highest level of animal feed intake will be achieved at the following values of the main parameters: pH – 6.5; the moisture – 9 %; the protein concentration – 85 %; the particle size – 0.55 mm; the energy value – 267 kcal/100 g feed. The adequacy of the dependence for the input variables – the moisture feed and concentration of the protein component – is confirmed by the experimental investigations. This paper can be used to generate the optimal prescription composition for functional and technological characteristics of the samples in order to create balanced extruded feeds.

  14. Growth-Rate Dependent Regulation of tRNA Level and Charging in Bacillus licheniformis.

    Science.gov (United States)

    Ferro, Iolanda; Liebeton, Klaus; Ignatova, Zoya

    2017-10-13

    Cellular growth crucially depends on protein synthesis and the abundance of translational components. Among them, aminoacyl-tRNAs play a central role in biosynthesis and shape the kinetics of mRNA translation, thus influencing protein production. Here, we used microarray-based approaches to determine the charging levels and tRNA abundance of Bacillus licheniformis. We observed an interesting cross-talk among tRNA expression, charging pattern, and growth rate. For a large subset of tRNAs, we found a co-regulated and augmented expression at high growth rate. Their tRNA aminoacylation level is kept relatively constant through riboswitch-regulated expression of the cognate aminoacyl-tRNA-synthetase (AARS). We show that AARSs with putative riboswitch-controlled expression are those charging tRNAs with amino acids which disfavor cell growth when individually added to the nutrient medium. Our results suggest that the riboswitch-regulated AARS expression in B. licheniformis is a powerful mechanism not only to maintain a constant ratio of aminoacyl-tRNA independent of the growth rate but concomitantly to control the intracellular level of free amino acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Health effects of low level radiation

    International Nuclear Information System (INIS)

    Chevillard, S.; Ugolin, N.; Lebeau, J.; Ory, K.

    2006-01-01

    Nuclear energy production is necessarily associated with the handling and storage of radioactive elements, which are liable to have deleterious effects on human health, and on environment. These deleterious effects are varied, but they greatly depend on the dose, which has been received, and the exposure type. Therefore, only intense and massive exposures are liable to be clinically detected. They can entail immediate consequences, even lead to the person's death. Thanks to safety measures, which have been implemented to an international scale, this occurs very rarely. Excluding extensive accidental cases, medical irradiation for therapeutic use and conflicts, workers and population in general are exposed to low doses and low dose-rates. Low dose exposures, resulting from either a contamination or an external irradiation are more frequent. In fact, we could say that the whole humanity is concerned by natural exposure, which varies depending on regions, as well as by medical exposure, which varies depending on the medicalisation status of the country. (author)

  16. Determinants of Blood Brain-Derived Neurotrophic Factor Blood Levels in Patients with Alcohol Use Disorder.

    Science.gov (United States)

    Nubukpo, Philippe; Ramoz, Nicolas; Girard, Murielle; Malauzat, Dominique; Gorwood, Philip

    2017-07-01

    Blood brain-derived neurotrophic factor (BDNF) levels are influenced by both addiction and mood disorders, as well as somatic conditions, gender, and genetic polymorphisms, leading to widely varying results. Depressive symptoms and episodes are frequently observed in patients with alcohol use disorder, and vary widely over time, making it a challenge to determine which aspects are specifically involved in variations of serum BDNF levels in this population. We assessed 227 patients with alcohol dependence involved in a detoxification program, at baseline and after a follow-up of 6 months, for the Alcohol Use Disorders Identification Test score, the length of alcohol dependence, and the number of past detoxification programs. The Beck Depression Inventory and information on current tobacco and alcohol use, suicidal ideation, body mass index, age, gender, and psychotropic treatments were also collected. Serum BDNF (ELISA) and 2 genetic polymorphisms of the BDNF gene (Val33Met and rs962369) were analyzed. The presence of the Met allele, 2 markers of the history of alcohol dependence (gamma glutamyl transferase and the number of past treatments in detoxification programs), and the presence of a depressive episode (but not depressive score) were significantly associated with the 2 blood levels of BDNF at baseline and after 6 months. After controlling for baseline BDNF levels, the presence of the Met allele and an ongoing depressive episode were the only variables associated with changes in BNDF levels after 6 months. Low serum BDNF levels are associated with characteristics related to alcohol consumption and mood disorders, and variants of the BDNF gene in alcohol use disorder patients. The factors that most strongly influenced changes in serum BDNF levels following treatment in an alcohol detoxification program were variants of the BDNF gene and ongoing depression. Copyright © 2017 by the Research Society on Alcoholism.

  17. Entropy squeezing for a two-level atom in the Jaynes-Cummings model with an intensity-depend coupling

    Institute of Scientific and Technical Information of China (English)

    李春先; 方卯发

    2003-01-01

    We study the squeezing for a two-level atom in the Jaynes-Cummings model with intensity-dependent coupling using quantum information entropy, and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing. Our results show that, the squeezed component number depends on the atomic initial distribution angle, while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing. Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.

  18. Entropy squeezing for a two—level atom in the Jaynes—Cummings model with an intensity—depend coupling

    Institute of Scientific and Technical Information of China (English)

    李春先; 方卯发; 等

    2003-01-01

    We study the squeezing for a two-level atom in the Jaynes-Cumings model with intensity-dependent coupling using quantum information entropy,and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing.Our results show that,the squeezed component number depends on the atomic initial distribution angle,while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing.Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.

  19. Effect of intra- and interspecific competition on the performance of native and invasive species of Impatiens under varying levels of shade and moisture.

    Science.gov (United States)

    Skálová, Hana; Jarošík, Vojtěch; Dvořáčková, Śárka; Pyšek, Petr

    2013-01-01

    Many alien plants are thought to be invasive because of unique traits and greater phenotypic plasticity relative to resident species. However, many studies of invasive species are unable to quantify the importance of particular traits and phenotypic plasticity in conferring invasive behavior because traits used in comparative studies are often measured in a single environment and by using plants from a single population. To obtain a deeper insight into the role of environmental factors, local differences and competition in plant invasions, we compared species of Impatiens (Balsaminaceae) of different origin and invasion status that occur in central Europe: native I. noli-tangere and three alien species (highly invasive I. glandulifera, less invasive I. parviflora and potentially invasive I. capensis). In two experiments we harvested late-stage reproductive plants to estimate performance. The first experiment quantified how populations differed in performance under varying light and moisture levels in the absence of competition. The second experiment quantified performance across these environments in the presence of intra- and inter-specific competition. The highly invasive I. glandulifera was the strongest competitor, was the tallest and produced the greatest biomass. Small size and high plasticity were characteristic for I. parviflora. This species appeared to be the second strongest competitor, especially under low soil moisture. The performance of I. capensis was within the range of the other Impatiens species studied, but sometimes limited by alien competitors. Our results suggest that invasion success within the genus Impatiens depends on the ability to grow large under a range of environmental conditions, including competition. The invasive species also exhibited greater phenotypic plasticity across environmental conditions than the native species. Finally, the decreased performance of the native I. noli-tangere in competition with other species studied

  20. Effect of intra- and interspecific competition on the performance of native and invasive species of Impatiens under varying levels of shade and moisture.

    Directory of Open Access Journals (Sweden)

    Hana Skálová

    Full Text Available Many alien plants are thought to be invasive because of unique traits and greater phenotypic plasticity relative to resident species. However, many studies of invasive species are unable to quantify the importance of particular traits and phenotypic plasticity in conferring invasive behavior because traits used in comparative studies are often measured in a single environment and by using plants from a single population. To obtain a deeper insight into the role of environmental factors, local differences and competition in plant invasions, we compared species of Impatiens (Balsaminaceae of different origin and invasion status that occur in central Europe: native I. noli-tangere and three alien species (highly invasive I. glandulifera, less invasive I. parviflora and potentially invasive I. capensis. In two experiments we harvested late-stage reproductive plants to estimate performance. The first experiment quantified how populations differed in performance under varying light and moisture levels in the absence of competition. The second experiment quantified performance across these environments in the presence of intra- and inter-specific competition. The highly invasive I. glandulifera was the strongest competitor, was the tallest and produced the greatest biomass. Small size and high plasticity were characteristic for I. parviflora. This species appeared to be the second strongest competitor, especially under low soil moisture. The performance of I. capensis was within the range of the other Impatiens species studied, but sometimes limited by alien competitors. Our results suggest that invasion success within the genus Impatiens depends on the ability to grow large under a range of environmental conditions, including competition. The invasive species also exhibited greater phenotypic plasticity across environmental conditions than the native species. Finally, the decreased performance of the native I. noli-tangere in competition with other

  1. A model to increase rehabilitation adherence to home exercise programmes in patients with varying levels of self-efficacy.

    Science.gov (United States)

    Picha, Kelsey J; Howell, Dana M

    2018-03-01

    Patient adherence to rehabilitation programmes is frequently low - particularly adherence to home exercise programmes. Home exercise programmes have been identified as complementary to clinic-based physical therapy in an orthopaedic setting. Barriers to patient adherence have previously been identified within the literature. Low self-efficacy is a barrier to adherence that clinicians have the ability to have an impact on and improve. The theory of self-efficacy is defined as a person's confidence in their ability to perform a task. This theory examines the ability of a person to change through exerting control over inner processes of goal setting, self-monitoring, feedback, problem solving and self-evaluation. If clinicians are able to identify patients with low self-efficacy prior to the prescription of a home exercise programme, adjustments to individualized care can be implemented. Individualized care based on improving self-efficacy for home exercise programmes may improve patient adherence to these programmes. The purpose of this article was to use the theory of self-efficacy to direct clinicians in providing individualized programmes to patients with varying levels of self-efficacy. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Irradiation creep and creep rupture of titanium-modified austenitic stainless steels and their dependence on cold work level

    International Nuclear Information System (INIS)

    Garner, F.A.; Hamilton, M.L.; Eiholzer, C.R.; Toloczko, M.B.; Kumar, A.S.

    1991-11-01

    A titanium-modified austenitic type stainless steel was tested at three cold work levels to determine its creep and creep rupture properties under both thermal aging and neutron irradiation conditions. Both the thermal and irradiation creep behavior exhibit a complex non-monotonic relationship with cold work level that reflects the competition between a number of stress-sensitive and temperature-dependent microstructural processes. Increasing the degree of cold work to 30% from the conventional 20% level was detrimental to its performance, especially for applications above 550 degrees c. The 20% cold work level is preferable to the 10% level, in terms of both in-reactor creep rupture response and initial strength

  3. The changes in levels of C-P and insulin in glucose tolerance test in rats with experimental non-insulin dependent diabetes mellitus

    International Nuclear Information System (INIS)

    Liu Xinqiu; Lei Ming

    2001-01-01

    The changes in levels of C-P and insulin were investigated in the GT test in rats with non-insulin dependent diabetes mellitus. In order to establish a model of non-insulin dependent diabetes mellitus (NIDDM), the authors injected rats with small dose streptozocoi (i.v.). Two weeks after the injection, the rats developed impaired glucose tolerance (IGT). Then, they were fed with high energy diet for eight weeks to form NIDDM. The results showed that the highest peak time of C-P and insulin in NIDDM was remarkably later than that in normal subjects, the highest peak time was in two hours (P < 0.05). The data suggest that level of C-P could accurately respond to level of insulin, and this experimental non-insulin dependent diabetes mellitus model is ideal

  4. Mean Square Exponential Stability of Stochastic Switched System with Interval Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Manlika Rajchakit

    2012-01-01

    Full Text Available This paper is concerned with mean square exponential stability of switched stochastic system with interval time-varying delays. The time delay is any continuous function belonging to a given interval, but not necessary to be differentiable. By constructing a suitable augmented Lyapunov-Krasovskii functional combined with Leibniz-Newton’s formula, a switching rule for the mean square exponential stability of switched stochastic system with interval time-varying delays and new delay-dependent sufficient conditions for the mean square exponential stability of the switched stochastic system are first established in terms of LMIs. Numerical example is given to show the effectiveness of the obtained result.

  5. Robust filtering for uncertain systems a parameter-dependent approach

    CERN Document Server

    Gao, Huijun

    2014-01-01

    This monograph provides the reader with a systematic treatment of robust filter design, a key issue in systems, control and signal processing, because of the fact that the inevitable presence of uncertainty in system and signal models often degrades the filtering performance and may even cause instability. The methods described are therefore not subject to the rigorous assumptions of traditional Kalman filtering. The monograph is concerned with robust filtering for various dynamical systems with parametric uncertainties, and focuses on parameter-dependent approaches to filter design. Classical filtering schemes, like H2 filtering and H¥ filtering, are addressed, and emerging issues such as robust filtering with constraints on communication channels and signal frequency characteristics are discussed. The text features: ·        design approaches to robust filters arranged according to varying complexity level, and emphasizing robust filtering in the parameter-dependent framework for the first time; ·...

  6. Varying Use of Conceptual Metaphors across Levels of Expertise in Thermodynamics

    Science.gov (United States)

    Jeppsson, Fredrik; Haglund, Jesper; Amin, Tamer G.

    2015-04-01

    Many studies have previously focused on how people with different levels of expertise solve physics problems. In early work, focus was on characterising differences between experts and novices and a key finding was the central role that propositionally expressed principles and laws play in expert, but not novice, problem-solving. A more recent line of research has focused on characterising continuity between experts and novices at the level of non-propositional knowledge structures and processes such as image-schemas, imagistic simulation and analogical reasoning. This study contributes to an emerging literature addressing the coordination of both propositional and non-propositional knowledge structures and processes in the development of expertise. Specifically, in this paper, we compare problem-solving across two levels of expertise-undergraduate students of chemistry and Ph.D. students in physical chemistry-identifying differences in how conceptual metaphors (CMs) are used (or not) to coordinate propositional and non-propositional knowledge structures in the context of solving problems on entropy. It is hypothesised that the acquisition of expertise involves learning to coordinate the use of CMs to interpret propositional (linguistic and mathematical) knowledge and apply it to specific problem situations. Moreover, we suggest that with increasing expertise, the use of CMs involves a greater degree of subjective engagement with physical entities and processes. Implications for research on learning and instructional practice are discussed. Third contribution to special issue entitled: Conceptual metaphor and embodied cognition in science learning

  7. Time-varying causality between energy consumption, CO2 emissions, and economic growth: evidence from US states.

    Science.gov (United States)

    Tzeremes, Panayiotis

    2018-02-01

    This study is the first attempt to investigate the relationship between CO 2 emissions, energy consumption, and economic growth at a state level, for the 50 US states, through a time-varying causality approach using annual data over the periods 1960-2010. The time-varying causality test facilitates the better understanding of the causal relationship between the covariates owing to the fact that it might identify causalities when the time-constant hypothesis is rejected. Our findings indicate the existence of a time-varying causality at the state level. Specifically, the results probe eight bidirectional time-varying causalities between energy consumption and CO 2 emission, six cases of two-way time-varying causalities between economic growth and energy consumption, and five bidirectional time-varying causalities between economic growth and CO 2 emission. Moreover, we examine the traditional environmental Kuznets curve hypothesis for the states. Notably, our results do not endorse the validity of the EKC, albeit the majority of states support an inverted N-shaped relationship. Lastly, we can identify multiple policy implications based on the empirical results.

  8. Enhanced intensity dependence and aggression history indicate previous regular ecstasy use in abstinent polydrug users.

    Science.gov (United States)

    Wan, Li; Baldridge, Robyn M; Colby, Amanda M; Stanford, Matthew S

    2009-11-13

    Intensity dependence is an electrophysiological measure of intra-individual stability of the augmenting/reducing characteristic of N1/ P2 event-related potential amplitudes in response to stimuli of varying intensities. Abstinent ecstasy users typically show enhanced intensity dependence and higher levels of impulsivity and aggression. Enhanced intensity dependence and high impulsivity and aggression levels may be due to damage in the brain's serotonergic neurons as a result of ecstasy use. The present study investigated whether intensity dependence, impulsivity and aggression history can be used as indicators of previous chronic ecstasy usage. Forty-four abstinent polydrug users (8 women; age 19 to 61 years old) were recruited. All participants were currently residents at a local substance abuse facility receiving treatment and had been free of all drugs for a minimum of 21 days. The study found significantly enhanced intensity dependence of tangential dipole source activity and a history of more aggressive behavior in those who had previously been involved in chronic ecstasy use. Intensity dependence of the tangential dipole source and aggressive behavior history correctly identified 73.3% of those who had been regular ecstasy users and 78.3% of those who had not. Overall, 76.3% of the participants were correctly classified.

  9. Dependence of reaction pressure on deposition and properties of boron-doped freestanding diamond films

    International Nuclear Information System (INIS)

    Li Liuan; Li Hongdong; Lue Xianyi; Cheng Shaoheng; Wang Qiliang; Ren Shiyuan; Liu Junwei; Zou Guangtian

    2010-01-01

    In this paper, we investigate the reaction pressure-dependent growth and properties of boron-doped freestanding diamond films, synthesized by hot filament chemical vapor deposition (HFCVD) at different boron-doping levels. With the decrease in pressure, the growth feature of the films varies from mixed [1 1 1] and [1 1 0] to dominated [1 1 1] texture. The low reaction pressure, as well as high boron-doping level, results in the increase (decrease) of carrier concentration (resistivity). The high concentration of atomic hydrogen in the ambient and preferable [1 1 1] growth, due to the low reaction pressure, is available for the enhancement of boron doping. The estimated residual stress increases with increase in the introducing boron level.

  10. Optimal Consumption and Investment under Time-Varying Relative Risk Aversion

    DEFF Research Database (Denmark)

    Steffensen, Mogens

    2011-01-01

    We consider the continuous time consumption-investment problem originally formalized and solved by Merton in case of constant relative risk aversion. We present a complete solution for the case where relative risk aversion with respect to consumption varies with time, having in mind an investor...... with age-dependent risk aversion. This provides a new motivation for life-cycle investment rules. We study the optimal consumption and investment rules, in particular in the case where the relative risk aversion with respect to consumption is increasing with age....

  11. Frequency-scanning interferometry using a time-varying Kalman filter for dynamic tracking measurements.

    Science.gov (United States)

    Jia, Xingyu; Liu, Zhigang; Tao, Long; Deng, Zhongwen

    2017-10-16

    Frequency scanning interferometry (FSI) with a single external cavity diode laser (ECDL) and time-invariant Kalman filtering is an effective technique for measuring the distance of a dynamic target. However, due to the hysteresis of the piezoelectric ceramic transducer (PZT) actuator in the ECDL, the optical frequency sweeps of the ECDL exhibit different behaviors, depending on whether the frequency is increasing or decreasing. Consequently, the model parameters of Kalman filter appear time varying in each iteration, which produces state estimation errors with time-invariant filtering. To address this, in this paper, a time-varying Kalman filter is proposed to model the instantaneous movement of a target relative to the different optical frequency tuning durations of the ECDL. The combination of the FSI method with the time-varying Kalman filter was theoretically analyzed, and the simulation and experimental results show the proposed method greatly improves the performance of dynamic FSI measurements.

  12. Maternal high-fat diet and offspring expression levels of vitamin K-dependent proteins.

    Science.gov (United States)

    Lanham, S A; Cagampang, F R; Oreffo, R O C

    2014-12-01

    Studies suggest that bone growth and development and susceptibility to vascular disease in later life are influenced by maternal nutrition during intrauterine and early postnatal life. There is evidence for a role of vitamin K-dependent proteins (VKDPs) including osteocalcin, matrix Gla protein, periostin, and growth-arrest specific- protein 6, in both bone and vascular development. We have examined whether there are alterations in these VKDPs in bone and vascular tissue from offspring of mothers subjected to a nutritional challenge: a high-fat diet during pregnancy and postnatally, using 6-week-old mouse offspring. Bone site-specific and sex-specific differences across femoral and vertebral bone in male and female offspring were observed. Overall a high-fat maternal diet and offspring diet exacerbated the bone changes observed. Sex-specific differences and tissue-specific differences were observed in VKDP levels in aorta tissue from high-fat diet-fed female offspring from high-fat diet-fed mothers displaying increased levels of Gas6 and Ggcx compared with those of female controls. In contrast, differences were seen in VKDP levels in femoral bone of female offspring with lower expression levels of Mgp in offspring of mothers fed a high-fat diet compared with those of controls. We observed a significant correlation in Mgp expression levels within the femur to measures of bone structure of the femur and vertebra, particularly in the male offspring cohort. In summary, the current study has highlighted the importance of maternal nutrition on offspring bone development and the correlation of VKDPs to bone structure.

  13. Time-dependent 2-stream particle transport

    International Nuclear Information System (INIS)

    Corngold, Noel

    2015-01-01

    Highlights: • We consider time-dependent transport in the 2-stream or “rod” model via an attractive matrix formalism. • After reviewing some classical problems in homogeneous media we discuss transport in materials with whose density may vary. • There we achieve a significant contraction of the underlying Telegrapher’s equation. • We conclude with a discussion of stochastics, treated by the “first-order smoothing approximation.” - Abstract: We consider time-dependent transport in the 2-stream or “rod” model via an attractive matrix formalism. After reviewing some classical problems in homogeneous media we discuss transport in materials whose density may vary. There we achieve a significant contraction of the underlying Telegrapher’s equation. We conclude with a discussion of stochastics, treated by the “first-order smoothing approximation.”

  14. Ck2-Dependent Phosphorylation Is Required to Maintain Pax7 Protein Levels in Proliferating Muscle Progenitors.

    Directory of Open Access Journals (Sweden)

    Natalia González

    Full Text Available Skeletal muscle regeneration and long term maintenance is directly link to the balance between self-renewal and differentiation of resident adult stem cells known as satellite cells. In turn, satellite cell fate is influenced by a functional interaction between the transcription factor Pax7 and members of the MyoD family of muscle regulatory factors. Thus, changes in the Pax7-to-MyoD protein ratio may act as a molecular rheostat fine-tuning acquisition of lineage identity while preventing precocious terminal differentiation. Pax7 is expressed in quiescent and proliferating satellite cells, while its levels decrease sharply in differentiating progenitors Pax7 is maintained in cells (reacquiring quiescence. While the mechanisms regulating Pax7 levels based on differentiation status are not well understood, we have recently described that Pax7 levels are directly regulated by the ubiquitin-ligase Nedd4, thus promoting proteasome-dependent Pax7 degradation in differentiating satellite cells. Here we show that Pax7 levels are maintained in proliferating muscle progenitors by a mechanism involving casein kinase 2-dependent Pax7 phosphorylation at S201. Point mutations preventing S201 phosphorylation or casein kinase 2 inhibition result in decreased Pax7 protein in proliferating muscle progenitors. Accordingly, this correlates directly with increased Pax7 ubiquitination. Finally, Pax7 down regulation induced by casein kinase 2 inhibition results in precocious myogenic induction, indicating early commitment to terminal differentiation. These observations highlight the critical role of post translational regulation of Pax7 as a molecular switch controlling muscle progenitor fate.

  15. Time-varying Concurrent Risk of Extreme Droughts and Heatwaves in California

    Science.gov (United States)

    Sarhadi, A.; Diffenbaugh, N. S.; Ausin, M. C.

    2016-12-01

    Anthropogenic global warming has changed the nature and the risk of extreme climate phenomena such as droughts and heatwaves. The concurrent of these nature-changing climatic extremes may result in intensifying undesirable consequences in terms of human health and destructive effects in water resources. The present study assesses the risk of concurrent extreme droughts and heatwaves under dynamic nonstationary conditions arising from climate change in California. For doing so, a generalized fully Bayesian time-varying multivariate risk framework is proposed evolving through time under dynamic human-induced environment. In this methodology, an extreme, Bayesian, dynamic copula (Gumbel) is developed to model the time-varying dependence structure between the two different climate extremes. The time-varying extreme marginals are previously modeled using a Generalized Extreme Value (GEV) distribution. Bayesian Markov Chain Monte Carlo (MCMC) inference is integrated to estimate parameters of the nonstationary marginals and copula using a Gibbs sampling method. Modelled marginals and copula are then used to develop a fully Bayesian, time-varying joint return period concept for the estimation of concurrent risk. Here we argue that climate change has increased the chance of concurrent droughts and heatwaves over decades in California. It is also demonstrated that a time-varying multivariate perspective should be incorporated to assess realistic concurrent risk of the extremes for water resources planning and management in a changing climate in this area. The proposed generalized methodology can be applied for other stochastic nature-changing compound climate extremes that are under the influence of climate change.

  16. Growth temperature dependence of Si doping efficiency and compensating deep level defect incorporation in Al0.7Ga0.3N

    International Nuclear Information System (INIS)

    Armstrong, Andrew M.; Moseley, Michael W.; Allerman, Andrew A.; Crawford, Mary H.; Wierer, Jonathan J.

    2015-01-01

    The growth temperature dependence of Si doping efficiency and deep level defect formation was investigated for n-type Al 0.7 Ga 0.3 N. It was observed that dopant compensation was greatly reduced with reduced growth temperature. Deep level optical spectroscopy and lighted capacitance-voltage were used to understand the role of acceptor-like deep level defects on doping efficiency. Deep level defects were observed at 2.34 eV, 3.56 eV, and 4.74 eV below the conduction band minimum. The latter two deep levels were identified as the major compensators because the reduction in their concentrations at reduced growth temperature correlated closely with the concomitant increase in free electron concentration. Possible mechanisms for the strong growth temperature dependence of deep level formation are considered, including thermodynamically driven compensating defect formation that can arise for a semiconductor with very large band gap energy, such as Al 0.7 Ga 0.3 N

  17. Dependent Human Error Probability Assessment

    International Nuclear Information System (INIS)

    Simic, Z.; Mikulicic, V.; Vukovic, I.

    2006-01-01

    This paper presents an assessment of the dependence between dynamic operator actions modeled in a Nuclear Power Plant (NPP) PRA and estimate the associated impact on Core damage frequency (CDF). This assessment was done improve HEP dependencies implementation inside existing PRA. All of the dynamic operator actions modeled in the NPP PRA are included in this assessment. Determining the level of HEP dependence and the associated influence on CDF are the major steps of this assessment. A decision on how to apply the results, i.e., should permanent HEP model changes be made, is based on the resulting relative CDF increase. Some CDF increase was selected as a threshold based on the NPP base CDF value and acceptance guidelines from the Regulatory Guide 1.174. HEP dependence resulting in a CDF increase of > 5E-07 would be considered potential candidates for specific incorporation into the baseline model. The approach used to judge the level of dependence between operator actions is based on dependency level categories and conditional probabilities developed in the Handbook of Human Reliability Analysis with Emphasis on Nuclear Power Plant Applications NUREG/CR-1278. To simplify the process, NUREG/CR-1278 identifies five levels of dependence: ZD (zero dependence), LD (low dependence), MD (moderate dependence), HD (high dependence), and CD (complete dependence). NUREG/CR-1278 also identifies several qualitative factors that could be involved in determining the level of dependence. Based on the NUREG/CR-1278 information, Time, Function, and Spatial attributes were judged to be the most important considerations when determining the level of dependence between operator actions within an accident sequence. These attributes were used to develop qualitative criteria (rules) that were used to judge the level of dependence (CD, HD, MD, LD, ZD) between the operator actions. After the level of dependence between the various HEPs is judged, quantitative values associated with the

  18. Time-Varying Dynamic Properties of Offshore Wind Turbines Evaluated by Modal Testing

    DEFF Research Database (Denmark)

    Damgaard, Mads; Andersen, J. K. F.; Ibsen, Lars Bo

    2014-01-01

    resonance of the wind turbine structure. In this paper, free vibration tests and a numerical Winkler type approach are used to evaluate the dynamic properties of a total of 30 offshore wind turbines located in the North Sea. Analyses indicate time-varying eigenfrequencies and damping ratios of the lowest...... structural eigenmode. Isolating the oscillation oil damper performance, moveable seabed conditions may lead to the observed time dependency....

  19. Wood-energy: success depends on the price of fossil energies and on the carbon tax level

    International Nuclear Information System (INIS)

    Defaye, Serge; Maindrault, Marc

    2016-01-01

    Illustrated by several graphs indicating the structure of fossil energy prices, the comparison between domestic fuel and wood-energy for public network exploitation, the levels of fossil prices and carbon tax for non-subsidised projects, this article analyses the development of biomass (and more particularly wood-energy), the success of which depends on the price of fossil energies and on the carbon tax level. It outlines the differences of price-building elements between fossil and renewable heat, that subsidies are necessary if reference prices are low. It discusses the influence of carbon tax level and of fossil prices. It finally identifies conditions to be met (reduction of fossil energy supply and therefore higher fossil prices, introduction of a carbon tax) to reach COP objectives

  20. Intracellular calcium levels can regulate Importin-dependent nuclear import

    International Nuclear Information System (INIS)

    Kaur, Gurpreet; Ly-Huynh, Jennifer D.; Jans, David A.

    2014-01-01

    Highlights: • High intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import. • The effect of Ca 2+ on nuclear import does not relate to changes in the nuclear pore. • High intracellular calcium can result in mislocalisation of Impβ1, Ran and RCC1. - Abstract: We previously showed that increased intracellular calcium can modulate Importin (Imp)β1-dependent nuclear import of SRY-related chromatin remodeling proteins. Here we extend this work to show for the first time that high intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import generally. The basis of this relates to the mislocalisation of the transport factors Impβ1 and Ran, which show significantly higher nuclear localization in contrast to various other factors, and RCC1, which shows altered subnuclear localisation. The results here establish for the first time that intracellular calcium modulates conventional nuclear import through direct effects on the nuclear transport machinery

  1. Intracellular calcium levels can regulate Importin-dependent nuclear import

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Gurpreet; Ly-Huynh, Jennifer D.; Jans, David A., E-mail: David.Jans@monash.edu

    2014-07-18

    Highlights: • High intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import. • The effect of Ca{sup 2+} on nuclear import does not relate to changes in the nuclear pore. • High intracellular calcium can result in mislocalisation of Impβ1, Ran and RCC1. - Abstract: We previously showed that increased intracellular calcium can modulate Importin (Imp)β1-dependent nuclear import of SRY-related chromatin remodeling proteins. Here we extend this work to show for the first time that high intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import generally. The basis of this relates to the mislocalisation of the transport factors Impβ1 and Ran, which show significantly higher nuclear localization in contrast to various other factors, and RCC1, which shows altered subnuclear localisation. The results here establish for the first time that intracellular calcium modulates conventional nuclear import through direct effects on the nuclear transport machinery.

  2. Density dependence governs when population responses to multiple stressors are magnified or mitigated.

    Science.gov (United States)

    Hodgson, Emma E; Essington, Timothy E; Halpern, Benjamin S

    2017-10-01

    Population endangerment typically arises from multiple, potentially interacting anthropogenic stressors. Extensive research has investigated the consequences of multiple stressors on organisms, frequently focusing on individual life stages. Less is known about population-level consequences of exposure to multiple stressors, especially when exposure varies through life. We provide the first theoretical basis for identifying species at risk of magnified effects from multiple stressors across life history. By applying a population modeling framework, we reveal conditions under which population responses from stressors applied to distinct life stages are either magnified (synergistic) or mitigated. We find that magnification or mitigation critically depends on the shape of density dependence, but not the life stage in which it occurs. Stressors are always magnified when density dependence is linear or concave, and magnified or mitigated when it is convex. Using Bayesian numerical methods, we estimated the shape of density dependence for eight species across diverse taxa, finding support for all three shapes. © 2017 by the Ecological Society of America.

  3. Controllable deterioration rate for time-dependent demand and time-varying holding cost

    Directory of Open Access Journals (Sweden)

    Mishra Vinod Kumar

    2014-01-01

    Full Text Available In this paper, we develop an inventory model for non-instantaneous deteriorating items under the consideration of the facts: deterioration rate can be controlled by using the preservation technology (PT during deteriorating period, and holding cost and demand rate both are linear function of time, which was treated as constant in most of the deteriorating inventory models. So in this paper, we developed a deterministic inventory model for non-instantaneous deteriorating items in which both demand rate and holding cost are a linear function of time, deterioration rate is constant, backlogging rate is variable and depend on the length of the next replenishment, shortages are allowed and partially backlogged. The model is solved analytically by minimizing the total cost of the inventory system. The model can be applied to optimizing the total inventory cost of non-instantaneous deteriorating items inventory for the business enterprises, where the preservation technology is used to control the deterioration rate, and demand & holding cost both are a linear function of time.

  4. Monaural and binaural contributions to interaural-level-difference sensitivity in human auditory cortex.

    Science.gov (United States)

    Stecker, G Christopher; McLaughlin, Susan A; Higgins, Nathan C

    2015-10-15

    Whole-brain functional magnetic resonance imaging was used to measure blood-oxygenation-level-dependent (BOLD) responses in human auditory cortex (AC) to sounds with intensity varying independently in the left and right ears. Echoplanar images were acquired at 3 Tesla with sparse image acquisition once per 12-second block of sound stimulation. Combinations of binaural intensity and stimulus presentation rate were varied between blocks, and selected to allow measurement of response-intensity functions in three configurations: monaural 55-85 dB SPL, binaural 55-85 dB SPL with intensity equal in both ears, and binaural with average binaural level of 70 dB SPL and interaural level differences (ILD) ranging ±30 dB (i.e., favoring the left or right ear). Comparison of response functions equated for contralateral intensity revealed that BOLD-response magnitudes (1) generally increased with contralateral intensity, consistent with positive drive of the BOLD response by the contralateral ear, (2) were larger for contralateral monaural stimulation than for binaural stimulation, consistent with negative effects (e.g., inhibition) of ipsilateral input, which were strongest in the left hemisphere, and (3) also increased with ipsilateral intensity when contralateral input was weak, consistent with additional, positive, effects of ipsilateral stimulation. Hemispheric asymmetries in the spatial extent and overall magnitude of BOLD responses were generally consistent with previous studies demonstrating greater bilaterality of responses in the right hemisphere and stricter contralaterality in the left hemisphere. Finally, comparison of responses to fast (40/s) and slow (5/s) stimulus presentation rates revealed significant rate-dependent adaptation of the BOLD response that varied across ILD values. Copyright © 2015. Published by Elsevier Inc.

  5. Cortisol level

    Science.gov (United States)

    ... enable JavaScript. The cortisol blood test measures the level of cortisol in the blood. Cortisol is a ... in the morning. This is important, because cortisol level varies throughout the day. You may be asked ...

  6. Optical properties of Al nanostructures from time dependent density functional theory

    KAUST Repository

    Mokkath, Junais Habeeb; Schwingenschlö gl, Udo

    2016-01-01

    The optical properties of Al nanostructures are investigated by means of time dependent density functional theory, considering chains of varying length and ladders/stripes of varying aspect ratio. The absorption spectra show redshifting

  7. Phase dependence of optical bistability and multistability in a four-level quantum system near a plasmonic nanostructure

    International Nuclear Information System (INIS)

    Asadpour, Seyyed Hossein; Rahimpour Soleimani, H.

    2016-01-01

    The optical bistability and multistability properties of a four-level quantum system near a plasmonic nanostructure embedded in a unidirectional ring cavity are studied theoretically. Two orthogonal circularly polarized laser fields with the same frequency, different phases and electric fields amplitude are interacted by four-level quantum system. It is found that in the presence of the plasmonic nanostructure, the bistable behaviors related to one of the laser fields propagating through the unidirectional ring cavity can be modified by relative phase and amplitude control of another laser fields. Our obtained results show that the optical bistability can be converted into the optical multistability by varying the value of distance between the quantum system and the surface of the plasmonic nanostructure. Moreover, it is shown that under specific condition related to the distance, the lasing without population inversion can be obtained

  8. Phase dependence of optical bistability and multistability in a four-level quantum system near a plasmonic nanostructure

    Energy Technology Data Exchange (ETDEWEB)

    Asadpour, Seyyed Hossein; Rahimpour Soleimani, H., E-mail: Rahimpour@guilan.ac.ir [Computational Nanophysics Laboratory (CNL), Department of Physics, University of Guilan, Rasht (Iran, Islamic Republic of)

    2016-01-14

    The optical bistability and multistability properties of a four-level quantum system near a plasmonic nanostructure embedded in a unidirectional ring cavity are studied theoretically. Two orthogonal circularly polarized laser fields with the same frequency, different phases and electric fields amplitude are interacted by four-level quantum system. It is found that in the presence of the plasmonic nanostructure, the bistable behaviors related to one of the laser fields propagating through the unidirectional ring cavity can be modified by relative phase and amplitude control of another laser fields. Our obtained results show that the optical bistability can be converted into the optical multistability by varying the value of distance between the quantum system and the surface of the plasmonic nanostructure. Moreover, it is shown that under specific condition related to the distance, the lasing without population inversion can be obtained.

  9. Kinetics of gravity-driven slug flow in partially wettable capillaries of varying cross section

    Science.gov (United States)

    Nissan, Alon; Wang, Qiuling; Wallach, Rony

    2016-11-01

    A mathematical model for slug (finite liquid volume) motion in not-fully-wettable capillary tubes with sinusoidally varying cross-sectional areas was developed. The model, based on the Navier-Stokes equation, accounts for the full viscous terms due to nonuniform geometry, the inertial term, the slug's front and rear meniscus hysteresis effect, and dependence of contact angle on flow velocity (dynamic contact angle). The model includes a velocity-dependent film that is left behind the advancing slug, reducing its mass. The model was successfully verified experimentally by recording slug movement in uniform and sinusoidal capillary tubes with a gray-scale high-speed camera. Simulation showed that tube nonuniformity has a substantial effect on slug flow pattern: in a uniform tube it is monotonic and depends mainly on the slug's momentary mass/length; an undulating tube radius results in nonmonotonic flow characteristics. The static nonzero contact angle varies locally in nonuniform tubes owing to the additional effect of wall slope. Moreover, the nonuniform cross-sectional area induces slug acceleration, deceleration, blockage, and metastable-equilibrium locations. Increasing contact angle further amplifies the geometry effect on slug propagation. The developed model provides a modified means of emulating slug flow in differently wettable porous media for intermittent inlet water supply (e.g., raindrops on the soil surface).

  10. Asymptotic stability of discrete-time systems with time-varying delay subject to saturation nonlinearities

    International Nuclear Information System (INIS)

    Chen, S.-F.

    2009-01-01

    The asymptotic stability problem for discrete-time systems with time-varying delay subject to saturation nonlinearities is addressed in this paper. In terms of linear matrix inequalities (LMIs), a delay-dependent sufficient condition is derived to ensure the asymptotic stability. A numerical example is given to demonstrate the theoretical results.

  11. A behavioral asset pricing model with a time-varying second moment

    International Nuclear Information System (INIS)

    Chiarella, Carl; He Xuezhong; Wang, Duo

    2006-01-01

    We develop a simple behavioral asset pricing model with fundamentalists and chartists in order to study price behavior in financial markets when chartists estimate both conditional mean and variance by using a weighted averaging process. Through a stability, bifurcation, and normal form analysis, the market impact of the weighting process and time-varying second moment are examined. It is found that the fundamental price becomes stable (unstable) when the activities from both types of traders are balanced (unbalanced). When the fundamental price becomes unstable, the weighting process leads to different price dynamics, depending on whether the chartists act as either trend followers or contrarians. It is also found that a time-varying second moment of the chartists does not change the stability of the fundamental price, but it does influence the stability of the bifurcations. The bifurcation becomes stable (unstable) when the chartists are more (less) concerned about the market risk characterized by the time-varying second moment. Different routes to complicated price dynamics are also observed. The analysis provides an analytical foundation for the statistical analysis of the corresponding stochastic version of this type of behavioral model

  12. Development of an Improved Time Varying Loudness Model with the Inclusion of Binaural Loudness Summation

    Science.gov (United States)

    Charbonneau, Jeremy

    As the perceived quality of a product is becoming more important in the manufacturing industry, more emphasis is being placed on accurately predicting the sound quality of everyday objects. This study was undertaken to improve upon current prediction techniques with regard to the psychoacoustic descriptor of loudness and an improved binaural summation technique. The feasibility of this project was first investigated through a loudness matching experiment involving thirty-one subjects and pure tones of constant sound pressure level. A dependence of binaural summation on frequency was observed which had previously not been a subject of investigation in the reviewed literature. A follow-up investigation was carried out with forty-eight volunteers and pure tones of constant sensation level. Contrary to existing theories in literature the resulting loudness matches revealed an amplitude versus frequency relationship which confirmed the perceived increase in loudness when a signal was presented to both ears simultaneously as opposed to one ear alone. The resulting trend strongly indicated that the higher the frequency of the presented signal, the greater the increase in observed binaural summation. The results from each investigation were summarized into a single binaural summation algorithm and inserted into an improved time-varying loudness model. Using experimental techniques, it was demonstrated that the updated binaural summation algorithm was a considerable improvement over the state of the art approach for predicting the perceived binaural loudness. The improved function retained the ease of use from the original model while additionally providing accurate estimates of diotic listening conditions from monaural WAV files. It was clearly demonstrated using a validation jury test that the revised time-varying loudness model was a significant improvement over the previously standardized approach.

  13. Variation in levels of reactive oxygen species is explained by maternal identity, sex and body-size-corrected clutch size in a lizard

    Science.gov (United States)

    Olsson, Mats; Wilson, Mark; Uller, Tobias; Mott, Beth; Isaksson, Caroline

    2009-01-01

    Many organisms show differences between males and females in growth rate and crucial life history parameters, such as longevity. Considering this, we may expect levels of toxic metabolic by-products of the respiratory chain, such as reactive oxygen species (ROS), to vary with age and sex. Here, we analyse ROS levels in female Australian painted dragon lizards ( Ctenophorus pictus) and their offspring using fluorescent probes and flow cytometry. Basal level of four ROS species (singlet oxygen, peroxynitrite, superoxide and H2O2) measured with a combined marker, and superoxide measured specifically, varied significantly among families but not between the sexes. When blood cells from offspring were chemically encouraged to accelerate the electron transport chain by mitochondrial uncoupling, net superoxide levels were three times higher in daughters than sons (resulting in levels outside of the normal ROS range) and varied among mothers depending on offspring sex (significant interaction between maternal identity and offspring sex). In offspring, there were depressive effects on ROS of size-controlled relative clutch size, which relies directly on circulating levels of vitellogenin, a confirmed antioxidant in some species. Thus, levels of reactive oxygen species varies among females, offspring and in relation to reproductive investment in a manner that makes its regulatory processes likely targets of selection.

  14. Differential response of radish plants to supplemental ultraviolet-B radiation under varying NPK levels: chlorophyll fluorescence, gas exchange and antioxidants.

    Science.gov (United States)

    Singh, Suruchi; Kumari, Rima; Agrawal, Madhoolika; Agrawal, Shashi Bhushan

    2012-07-01

    Current and projected increases in ultraviolet-B (UV-B; 280-315 nm) radiation may alter crop growth and yield by modifying the physiological and biochemical functions. This study was conducted to assess the possibility of alleviating the negative effects of supplemental UV-B (sUV-B; 7.2 kJ m⁻² day⁻¹; 280-315 nm) on radish (Raphanus sativus var Pusa Himani) by modifying soil nitrogen (N), phosphorus (P) and potassium (K) levels. The N, P and K treatments were recommended dose of N, P and K, 1.5 times recommended dose of N, P and K, 1.5 times recommended dose of N and 1.5 times recommended dose of K. Plants showed variations in their response to UV-B radiation under varying soil NPK levels. The minimum damaging effects of sUV-B on photosynthesis rate and stomatal conductance coupled with minimum reduction in chlorophyll content were recorded for plants grown at recommended dose of NPK. Flavonoids increased under sUV-B except in plants grown at 1.5 times recommended dose of N. Lipid peroxidation (LPO) also increased in response to sUV-B at all NPK levels with maximum at 1.5 times recommended dose of K and minimum at recommended dose of NPK. This study revealed that sUV-B radiation negatively affected the radish plants by reducing the photosynthetic efficiency and increasing LPO. The plants grown at 1.5 times recommended dose of NPK/N/K could not enhance antioxidative potential to the extent as recorded at recommended dose of NPK and hence showed more sensitivity to sUV-B. Copyright © Physiologia Plantarum 2012.

  15. Opioid dependence - management in general practice.

    Science.gov (United States)

    Frei, Matthew

    2010-08-01

    Addiction to opioids, or opioid dependence, encompasses the biopsychosocial dysfunction seen in illicit heroin injectors, as well as aberrant behaviours in patients prescribed opioids for chronic nonmalignant pain. To outline the management of opioid dependence using opioid pharmacotherapy as part of a comprehensive chronic illness management strategy. The same principles and skills general practitioners employ in chronic illness management underpin the care of patients with opioid dependence. Opioid pharmacotherapy, with the substitution medications methadone and buprenorphine, is an effective management of opioid dependence. Training and regulatory requirements for prescribing opioid pharmacotherapies vary between jurisdictions, but this treatment should be within the scope of most Australian GPs.

  16. Joint route planning under varying market conditions

    NARCIS (Netherlands)

    Cruijssen, Frans; Bräysy, Olli; Dullaert, Wout; Fleuren, Hein; Salomon, Marc

    2007-01-01

    Purpose - To provide empirical evidence on the level of savings that can be attained by joint route planning and how these savings depend on specific market characteristics. Design/methodology/approach - Joint route planning is a measure that companies can take to decrease the costs of their

  17. Fast space-varying convolution using matrix source coding with applications to camera stray light reduction.

    Science.gov (United States)

    Wei, Jianing; Bouman, Charles A; Allebach, Jan P

    2014-05-01

    Many imaging applications require the implementation of space-varying convolution for accurate restoration and reconstruction of images. Here, we use the term space-varying convolution to refer to linear operators whose impulse response has slow spatial variation. In addition, these space-varying convolution operators are often dense, so direct implementation of the convolution operator is typically computationally impractical. One such example is the problem of stray light reduction in digital cameras, which requires the implementation of a dense space-varying deconvolution operator. However, other inverse problems, such as iterative tomographic reconstruction, can also depend on the implementation of dense space-varying convolution. While space-invariant convolution can be efficiently implemented with the fast Fourier transform, this approach does not work for space-varying operators. So direct convolution is often the only option for implementing space-varying convolution. In this paper, we develop a general approach to the efficient implementation of space-varying convolution, and demonstrate its use in the application of stray light reduction. Our approach, which we call matrix source coding, is based on lossy source coding of the dense space-varying convolution matrix. Importantly, by coding the transformation matrix, we not only reduce the memory required to store it; we also dramatically reduce the computation required to implement matrix-vector products. Our algorithm is able to reduce computation by approximately factoring the dense space-varying convolution operator into a product of sparse transforms. Experimental results show that our method can dramatically reduce the computation required for stray light reduction while maintaining high accuracy.

  18. Novel criteria for global exponential periodicity and stability of recurrent neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Song Qiankun

    2008-01-01

    In this paper, the global exponential periodicity and stability of recurrent neural networks with time-varying delays are investigated by applying the idea of vector Lyapunov function, M-matrix theory and inequality technique. We assume neither the global Lipschitz conditions on these activation functions nor the differentiability on these time-varying delays, which were needed in other papers. Several novel criteria are found to ascertain the existence, uniqueness and global exponential stability of periodic solution for recurrent neural network with time-varying delays. Moreover, the exponential convergence rate index is estimated, which depends on the system parameters. Some previous results are improved and generalized, and an example is given to show the effectiveness of our method

  19. Iodide Residues in Milk Vary between Iodine-Based Teat Disinfectants

    NARCIS (Netherlands)

    French, Elizabeth A; Mukai, Motoko; Zurakowski, Michael; Rauch, Bradley; Gioia, Gloria; Hillebrandt, Joseph R; Henderson, Mark; Schukken, Ynte H; Hemling, Thomas C

    Majority of iodine found in dairy milk comes from the diet and teat disinfection products used during milking process. The objective of this study was to evaluate the effects of 4 iodine-based teat dips on milk iodide concentrations varying in iodine level (0.25% vs. 0.5%, w/w), normal low viscosity

  20. Cardiovascular disease markers responses in male receiving improved-fat meat-products vary by initial LDL-cholesterol levels.

    Directory of Open Access Journals (Sweden)

    Paloma Celada

    2016-11-01

    Full Text Available Objectives: Cardiovascular disease (CVD is prevalent in people at high meat-product consumption. To study the effect of consuming different Pâté and Frankfurter formulations on clinical/emergent CVD biomarkers in male volunteers with different initial LDL-cholesterol levels (< and ³ 3.36 mmol/L. Method: Eighteen male volunteers with at least two CVD risk factors were enrolled in a crossover controlled study. Pork-products were consumed during 4wk: reduced-fat (RF, omega-3-enriched-RF (n-3RF, and normal-fat (NF. Pork-products were separated by 4wk washout. Lipids, lipoproteins, oxidized LDL (oxLDL, apolipoproteins (apo and their ratios, homocysteine (tHcys, arylesterase (AE, C-reactive protein (CRP, tumor necrotic factor (TNFa were tested. Results: The rate of change for AE, oxLDL, Lp(a, AE/HDL-cholesterol, LDL/apo B and AE/oxLDL ratios varied (p<0.05 among periods only in volunteers with LDLcholesterol ³3.36 mmol/L. TNFa decreased (p<0.05 among volunteers with low-normal LDL-cholesterol values while AE increased (p<0.01 in high LDL-cholesterol volunteers during the RF-period. AE increased while CRP decreased (both p<0.01 in low-normal LDL-cholesterol volunteers while AE (p<0.001 and apo B (p<0.01 increased in the high LDL-cholesterol group during the n-3RF-period. Total cholesterol (p<0.05 increased in the low/normal LDL-cholesterol group while tHcys decreased (p<0.05 in the high LDL-cholesterol group during the NF-period. Differences in response in volunteers with low-normal vs. high initial LDL-cholesterol levels to the n-3RF but not to the RF meat-products seem evident. Conclusions: Subjects with high LDL-cholesterol seem target for n-3RF products while subjects with LDL-cholesterol <3.36 mmol/L were more negatively affected by NF-products. Any generalization about functional meat product or consumption should be avoided.

  1. NAD+-Dependent Deacetylase Hst1p Controls Biosynthesis and Cellular NAD+ Levels in Saccharomyces cerevisiae

    OpenAIRE

    Bedalov, Antonio; Hirao, Maki; Posakony, Jeffrey; Nelson, Melisa; Simon, Julian A.

    2003-01-01

    Nicotine adenine dinucleotide (NAD+) performs key roles in electron transport reactions, as a substrate for poly(ADP-ribose) polymerase and NAD+-dependent protein deacetylases. In the latter two processes, NAD+ is consumed and converted to ADP-ribose and nicotinamide. NAD+ levels can be maintained by regeneration of NAD+ from nicotinamide via a salvage pathway or by de novo synthesis of NAD+ from tryptophan. Both pathways are conserved from yeast to humans. We describe a critical role of the ...

  2. A hepatitis C virus infection model with time-varying drug effectiveness: solution and analysis.

    Directory of Open Access Journals (Sweden)

    Jessica M Conway

    2014-08-01

    Full Text Available Simple models of therapy for viral diseases such as hepatitis C virus (HCV or human immunodeficiency virus assume that, once therapy is started, the drug has a constant effectiveness. More realistic models have assumed either that the drug effectiveness depends on the drug concentration or that the effectiveness varies over time. Here a previously introduced varying-effectiveness (VE model is studied mathematically in the context of HCV infection. We show that while the model is linear, it has no closed-form solution due to the time-varying nature of the effectiveness. We then show that the model can be transformed into a Bessel equation and derive an analytic solution in terms of modified Bessel functions, which are defined as infinite series, with time-varying arguments. Fitting the solution to data from HCV infected patients under therapy has yielded values for the parameters in the model. We show that for biologically realistic parameters, the predicted viral decay on therapy is generally biphasic and resembles that predicted by constant-effectiveness (CE models. We introduce a general method for determining the time at which the transition between decay phases occurs based on calculating the point of maximum curvature of the viral decay curve. For the parameter regimes of interest, we also find approximate solutions for the VE model and establish the asymptotic behavior of the system. We show that the rate of second phase decay is determined by the death rate of infected cells multiplied by the maximum effectiveness of therapy, whereas the rate of first phase decline depends on multiple parameters including the rate of increase of drug effectiveness with time.

  3. Blood Glucose Levels and Problem Behavior

    Science.gov (United States)

    Valdovinos, Maria G.; Weyand, David

    2006-01-01

    The relationship between varying blood glucose levels and problem behavior during daily scheduled activities was examined. The effects that varying blood glucose levels had on problem behavior during daily scheduled activities were examined. Prior research has shown that differing blood glucose levels can affect behavior and mood. Results of this…

  4. An Ecological Study on the Spatially Varying Relationship between County-Level Suicide Rates and Altitude in the United States

    Directory of Open Access Journals (Sweden)

    Hoehun Ha

    2018-04-01

    Full Text Available Suicide is a serious but preventable public health issue. Several previous studies have revealed a positive association between altitude and suicide rates at the county level in the contiguous United States. We assessed the association between suicide rates and altitude using a cross-county ecological study design. Data on suicide rates were obtained from a Web-based Injury Statistics Query and Reporting System (WISQARS, maintained by the U.S. National Center for Injury Prevention and Control (NCIPC. Altitude data were collected from the United States Geological Survey (USGS. We employed an ordinary least square (OLS regression to model the association between altitude and suicide rates in 3064 counties in the contiguous U.S. We conducted a geographically weighted regression (GWR to examine the spatially varying relationship between suicide rates and altitude after controlling for several well-established covariates. A significant positive association between altitude and suicide rates (average county rates between 2008 and 2014 was found in the dataset in the OLS model (R2 = 0.483, p < 0.001. Our GWR model fitted the data better, as indicated by an improved R2 (average: 0.62; range: 0.21–0.64 and a lower Akaike Information Criteria (AIC value (13,593.68 vs. 14,432.14 in the OLS model. The GWR model also significantly reduced the spatial autocorrelation, as indicated by Moran’s I test statistic (Moran’s I = 0.171; z = 33.656; p < 0.001 vs. Moran’s I = 0.323; z = 63.526; p < 0.001 in the OLS model. In addition, a stronger positive relationship was detected in areas of the northern regions, northern plain regions, and southeastern regions in the U.S. Our study confirmed a varying overall positive relationship between altitude and suicide. Future research may consider controlling more predictor variables in regression models, such as firearm ownership, religion, and access to mental health services.

  5. Age-dependent decline of beta-cell function in type 1 diabetes after diagnosis: a multi-centre longitudinal study

    DEFF Research Database (Denmark)

    Barker, A.; Lauria, A.; Schloot, N.

    2014-01-01

    C-peptide secretion is currently the only available clinical biomarker to measure residual β-cell function in type 1 diabetes. However, the natural history of C-peptide decline after diagnosis can vary considerably dependent upon several variables. We investigated the shape of C-peptide decline...... over time from type 1 diabetes onset in relation to age at diagnosis, HbA1c levels and insulin dose....

  6. Features of cryptic promoters and their varied reliance on bromodomain-containing factors.

    Directory of Open Access Journals (Sweden)

    Samantha G Pattenden

    Full Text Available The Set2-Rpd3S pathway is important for the control of transcription memory. Mutation of components of this pathway results in cryptic transcription initiation within the coding region of approximately 30% of yeast genes. Specifically, deletion of the Set2 histone methyltransferase or Rco1, a component of the Rpd3S histone deacetylase complex leads to hyperacetylation of certain open reading frames (ORFs. We used this mutant as a system to study the role of histone modifications and co-activator recruitment in preinitiation complex (PIC formation. Specifically, we looked at the dependence of promoters on the bromodomain-containing RSC complex and the Bdf1 protein. We found that the dependence of cryptic promoters for these proteins varied. Overall, our data indicate that cryptic promoters are independently regulated, and their activation is dependent on factors that govern gene activation at canonical promoters.

  7. Analysis of seafloor backscatter strength dependence on the survey azimuth using multibeam echosounder data

    Science.gov (United States)

    Lurton, Xavier; Eleftherakis, Dimitrios; Augustin, Jean-Marie

    2018-06-01

    The sediment backscatter strength measured by multibeam echosounders is a key feature for seafloor mapping either qualitative (image mosaics) or quantitative (extraction of classifying features). An important phenomenon, often underestimated, is the dependence of the backscatter level on the azimuth angle imposed by the survey line directions: strong level differences at varying azimuth can be observed in case of organized roughness of the seabed, usually caused by tide currents over sandy sediments. This paper presents a number of experimental results obtained from shallow-water cruises using a 300-kHz multibeam echosounder and specially dedicated to the study of this azimuthal effect, with a specific configuration of the survey strategy involving a systematic coverage of reference areas following "compass rose" patterns. The results show for some areas a very strong dependence of the backscatter level, up to about 10-dB differences at intermediate oblique angles, although the presence of these ripples cannot be observed directly—neither from the bathymetry data nor from the sonar image, due to the insufficient resolution capability of the sonar. An elementary modeling of backscattering from rippled interfaces explains and comforts these observations. The consequences of this backscatter dependence upon survey azimuth on the current strategies of backscatter data acquisition and exploitation are discussed.

  8. Haematopoietic depletion in vaccine-induced neonatal pancytopenia depends on both the titre and specificity of alloantibody and levels of MHC I expression.

    Science.gov (United States)

    Bell, Charlotte R; MacHugh, Niall D; Connelley, Timothy K; Degnan, Kathryn; Morrison, W Ivan

    2015-07-09

    Bovine Neonatal Pancytopenia (BNP) is a disease of calves characterised by haematopoietic depletion, mediated by ingestion of alloantibodies in colostrum. It has been linked epidemiologically to vaccination of the dams of affected calves with a particular vaccine (Pregsure) containing a novel adjuvant. Evidence suggests that BNP-alloantibodies are directed against MHC I molecules, induced by contaminant bovine cellular material from Madin-Darby Bovine Kidney (MDBK) cells used in the vaccine's production. We aimed to investigate the specificity of BNP-alloantibody for bovine MHC I alleles, particularly those expressed by MDBK cells, and whether depletion of particular cell types is due to differential MHC I expression levels. A complement-mediated cytotoxicity assay was used to assess functional serum alloantibody titres in BNP-dams, Pregsure-vaccinated dams with healthy calves, cows vaccinated with an alternative product and unvaccinated controls. Alloantibody specificity was investigated using transfected mouse lines expressing the individual MHC I alleles identified from MDBK cells and MHC I-defined bovine leukocyte lines. All BNP-dams and 50% of Pregsure-vaccinated cows were shown to have MDBK-MHC I specific alloantibodies, which cross-reacted to varying degrees with other MHC I genotypes. MHC I expression levels on different blood cell types, assessed by flow cytometry, were found to correlate with levels of alloantibody-mediated damage in vitro and in vivo. Alloantibody-killed bone marrow cells were shown to express higher levels of MHC I than undamaged cells. The results provide evidence that MHC I-specific alloantibodies play a dominant role in the pathogenesis of BNP. Haematopoietic depletion was shown to be dependent on the titre and specificity of alloantibody produced by individual cows and the density of surface MHC I expression by different cell types. Collectively, the results support the hypothesis that MHC I molecules originating from MDBK cells

  9. A simple analytical model for dynamics of time-varying target leverage ratios

    Science.gov (United States)

    Lo, C. F.; Hui, C. H.

    2012-03-01

    In this paper we have formulated a simple theoretical model for the dynamics of the time-varying target leverage ratio of a firm under some assumptions based upon empirical observations. In our theoretical model the time evolution of the target leverage ratio of a firm can be derived self-consistently from a set of coupled Ito's stochastic differential equations governing the leverage ratios of an ensemble of firms by the nonlinear Fokker-Planck equation approach. The theoretically derived time paths of the target leverage ratio bear great resemblance to those used in the time-dependent stationary-leverage (TDSL) model [Hui et al., Int. Rev. Financ. Analy. 15, 220 (2006)]. Thus, our simple model is able to provide a theoretical foundation for the selected time paths of the target leverage ratio in the TDSL model. We also examine how the pace of the adjustment of a firm's target ratio, the volatility of the leverage ratio and the current leverage ratio affect the dynamics of the time-varying target leverage ratio. Hence, with the proposed dynamics of the time-dependent target leverage ratio, the TDSL model can be readily applied to generate the default probabilities of individual firms and to assess the default risk of the firms.

  10. Effects of curved midline and varying width on the description of the effective diffusivity of Brownian particles

    Science.gov (United States)

    Chávez, Yoshua; Chacón-Acosta, Guillermo; Dagdug, Leonardo

    2018-05-01

    Axial diffusion in channels and tubes of smoothly-varying geometry can be approximately described as one-dimensional diffusion in the entropy potential with a position-dependent effective diffusion coefficient, by means of the modified Fick–Jacobs equation. In this work, we derive analytical expressions for the position-dependent effective diffusivity for two-dimensional asymmetric varying-width channels, and for three-dimensional curved midline tubes, formed by straight walls. To this end, we use a recently developed theoretical framework using the Frenet–Serret moving frame as the coordinate system (2016 J. Chem. Phys. 145 074105). For narrow tubes and channels, an effective one-dimensional description reducing the diffusion equation to a Fick–Jacobs-like equation in general coordinates is used. From this last equation, one can calculate the effective diffusion coefficient applying Neumann boundary conditions.

  11. Software Dependability and Safety Evaluations ESA's Initiative

    Science.gov (United States)

    Hernek, M.

    ESA has allocated funds for an initiative to evaluate Dependability and Safety methods of Software. The objectives of this initiative are; · More extensive validation of Safety and Dependability techniques for Software · Provide valuable results to improve the quality of the Software thus promoting the application of Dependability and Safety methods and techniques. ESA space systems are being developed according to defined PA requirement specifications. These requirements may be implemented through various design concepts, e.g. redundancy, diversity etc. varying from project to project. Analysis methods (FMECA. FTA, HA, etc) are frequently used during requirements analysis and design activities to assure the correct implementation of system PA requirements. The criticality level of failures, functions and systems is determined and by doing that the critical sub-systems are identified, on which dependability and safety techniques are to be applied during development. Proper performance of the software development requires the development of a technical specification for the products at the beginning of the life cycle. Such technical specification comprises both functional and non-functional requirements. These non-functional requirements address characteristics of the product such as quality, dependability, safety and maintainability. Software in space systems is more and more used in critical functions. Also the trend towards more frequent use of COTS and reusable components pose new difficulties in terms of assuring reliable and safe systems. Because of this, its dependability and safety must be carefully analysed. ESA identified and documented techniques, methods and procedures to ensure that software dependability and safety requirements are specified and taken into account during the design and development of a software system and to verify/validate that the implemented software systems comply with these requirements [R1].

  12. Holographic cinematography of time-varying reflecting and time-varying phase objects using a Nd:YAG laser

    Science.gov (United States)

    Decker, A. J.

    1982-01-01

    The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.

  13. Deformation aspects of time dependent fracture

    International Nuclear Information System (INIS)

    Li, C.Y.; Turner, A.P.L.; Diercks, D.R.; Laird, C.; Langdon, T.G.; Nix, W.D.; Swindeman, R.; Wolfer, W.G.; Woodford, D.A.

    1979-01-01

    For all metallic materials, particularly at elevated temperatures, deformation plays an important role in fracture. On the macro-continuum level, the inelastic deformation behavior of the material determines how stress is distributed in the body and thus determines the driving force for fracture. At the micro-continuum level, inelastic deformation alters the elastic stress singularity at the crack tip and so determines the local environment in which crack advance takes place. At the microscopic and mechanistic level, there are many possibilities for the mechanisms of deformation to be related to those for crack initiation and growth. At elevated temperatures, inelastic deformation in metallic systems is time dependent so that the distribution of stress in a body will vary with time, affecting conditions for crack initiation and propagation. Creep deformation can reduce the tendency for fracture by relaxing the stresses at geometric stress concentrations. It can also, under suitable constraints, cause a concentration of stresses at specific loading points as a result of relaxation elsewhere in the body. A combination of deformation and unequal heating, as in welding, can generate large residual stress which cannot be predicted from the external loads on the body. Acceleration of deformation by raising the temperature can be an effective way to relieve such residual stresses

  14. Mental Disorders in Substance Dependent Individuals as Compared to Non-Substance Dependent People in Hamadan, Iran

    Directory of Open Access Journals (Sweden)

    A. Heidari Pahlavian

    2011-10-01

    Full Text Available Introduction & Objective: There are several close links between substance dependency and mental disorders. Many people who regularly abuse drugs are also diagnosed with psychiatric disorders and vice versa. The high prevalence of this comorbidity has been documented in several studies, although most of the research has been carried out in only a few countries and the cultural validity of the data is unknown. Thus the aim of this study was the comparative investigation of mental disorders in drug dependent and non drug dependent persons in city of Hamadan.Materials & Methods: This study was a descriptive comparative research. 106 men aged 18 to 51 who sought treatment at addiction rehabilitation department of Hamadan were recruited in this study. Also 106 men in the same age range were matched with the first group. Data were collected through structured clinical interview for DSM-IV-TR and SCL 90-R questionnaire. Data were analyzed using t-test and correlation coefficient test.Results: The rate and severity of mental disorders in 9 studied Categories of disorders—phobia, anxiety, somatization, psychotism, depression, paranoid thoughts, aggression, interpersonal sensitivity and obsession-compulsion—were significantly higher among the addicts than the normal group.The level of severity was higher in depression, paranoid thoughts and interpersonal sensitivity than the other disorders. 63.5% of addicts suffered from some psychological disorders while the figures for no addicts were 28.8%. The prevalence of co-morbid psychiatric disorders varied with the pattern of addicts.Conclusion: This study showed that persons with substance dependence display more signs of psycho pathology and mental disorders in comparison with non- substance dependent people.(Sci J Hamadan Univ Med Sci 2011;18(3:22-28

  15. Time-varying BRDFs.

    Science.gov (United States)

    Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

    2007-01-01

    The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.

  16. Nonlinear control of linear parameter varying systems with applications to hypersonic vehicles

    Science.gov (United States)

    Wilcox, Zachary Donald

    The focus of this dissertation is to design a controller for linear parameter varying (LPV) systems, apply it specifically to air-breathing hypersonic vehicles, and examine the interplay between control performance and the structural dynamics design. Specifically a Lyapunov-based continuous robust controller is developed that yields exponential tracking of a reference model, despite the presence of bounded, nonvanishing disturbances. The hypersonic vehicle has time varying parameters, specifically temperature profiles, and its dynamics can be reduced to an LPV system with additive disturbances. Since the HSV can be modeled as an LPV system the proposed control design is directly applicable. The control performance is directly examined through simulations. A wide variety of applications exist that can be effectively modeled as LPV systems. In particular, flight systems have historically been modeled as LPV systems and associated control tools have been applied such as gain-scheduling, linear matrix inequalities (LMIs), linear fractional transformations (LFT), and mu-types. However, as the type of flight environments and trajectories become more demanding, the traditional LPV controllers may no longer be sufficient. In particular, hypersonic flight vehicles (HSVs) present an inherently difficult problem because of the nonlinear aerothermoelastic coupling effects in the dynamics. HSV flight conditions produce temperature variations that can alter both the structural dynamics and flight dynamics. Starting with the full nonlinear dynamics, the aerothermoelastic effects are modeled by a temperature dependent, parameter varying state-space representation with added disturbances. The model includes an uncertain parameter varying state matrix, an uncertain parameter varying non-square (column deficient) input matrix, and an additive bounded disturbance. In this dissertation, a robust dynamic controller is formulated for a uncertain and disturbed LPV system. The developed

  17. Habitat Modeling of Alien Plant Species at Varying Levels of Occupancy

    Directory of Open Access Journals (Sweden)

    Jennifer A. Brown

    2012-09-01

    Full Text Available Distribution models of invasive plants are very useful tools for conservation management. There are challenges in modeling expanding populations, especially in a dynamic environment, and when data are limited. In this paper, predictive habitat models were assessed for three invasive plant species, at differing levels of occurrence, using two different habitat modeling techniques: logistic regression and maximum entropy. The influence of disturbance, spatial and temporal heterogeneity, and other landscape characteristics is assessed by creating regional level models based on occurrence records from the USDA Forest Service’s Forest Inventory and Analysis database. Logistic regression and maximum entropy models were assessed independently. Ensemble models were developed to combine the predictions of the two analysis approaches to obtain a more robust prediction estimate. All species had strong models with Area Under the receiver operator Curve (AUC of >0.75. The species with the highest occurrence, Ligustrum spp., had the greatest agreement between the models (93%. Lolium arundinaceum had the most disagreement between models at 33% and the lowest AUC values. Overall, the strength of integrative modeling in assessing and understanding habitat modeling was demonstrated.

  18. Evaluation of physiological, growth and yield responses of a tropical oil crop (Brassica campestris L. var. Kranti) under ambient ozone pollution at varying NPK levels

    International Nuclear Information System (INIS)

    Singh, Poonam; Agrawal, Madhoolika; Agrawal, Shashi Bhushan

    2009-01-01

    A field study was conducted to evaluate the impact of ambient ozone on mustard (Brassica campestris L. var. Kranti) plants grown under recommended and 1.5 times recommended NPK doses at a rural site of India using filtered (FCs) and non-filtered open top chambers (NFCs). Ambient mean O 3 concentration varied from 41.65 to 54.2 ppb during the experiment. Plants growing in FCs showed higher photosynthetic rate at both NPK levels, but higher stomatal conductance only at recommended NPK. There were improvements in growth parameters and biomass of plants in FCs as compared to NFCs at both NPK levels with higher increments at 1.5 times recommended. Seed yield and harvest index decreased significantly only at recommended NPK in NFCs. Seed quality in terms of nutrients, protein and oil contents reduced in NFCs at recommended NPK. The application of 1.5 times recommended NPK provided protection against yield loss due to ambient O 3 . - NPK level above recommended alleviates the adverse effects of ambient ozone on a tropical mustard cultivar

  19. Evaluation of physiological, growth and yield responses of a tropical oil crop (Brassica campestris L. var. Kranti) under ambient ozone pollution at varying NPK levels

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Poonam [Laboratory of Air Pollution and Global Climate Change, Ecology Research Circle, Department of Botany, Banaras Hindu University, Varanasi 221005 (India); Agrawal, Madhoolika [Laboratory of Air Pollution and Global Climate Change, Ecology Research Circle, Department of Botany, Banaras Hindu University, Varanasi 221005 (India)], E-mail: madhoo58@yahoo.com; Agrawal, Shashi Bhushan [Laboratory of Air Pollution and Global Climate Change, Ecology Research Circle, Department of Botany, Banaras Hindu University, Varanasi 221005 (India)

    2009-03-15

    A field study was conducted to evaluate the impact of ambient ozone on mustard (Brassica campestris L. var. Kranti) plants grown under recommended and 1.5 times recommended NPK doses at a rural site of India using filtered (FCs) and non-filtered open top chambers (NFCs). Ambient mean O{sub 3} concentration varied from 41.65 to 54.2 ppb during the experiment. Plants growing in FCs showed higher photosynthetic rate at both NPK levels, but higher stomatal conductance only at recommended NPK. There were improvements in growth parameters and biomass of plants in FCs as compared to NFCs at both NPK levels with higher increments at 1.5 times recommended. Seed yield and harvest index decreased significantly only at recommended NPK in NFCs. Seed quality in terms of nutrients, protein and oil contents reduced in NFCs at recommended NPK. The application of 1.5 times recommended NPK provided protection against yield loss due to ambient O{sub 3}. - NPK level above recommended alleviates the adverse effects of ambient ozone on a tropical mustard cultivar.

  20. The amplitude and phase precision of 40 Hz auditory steady-state response depend on the level of arousal

    DEFF Research Database (Denmark)

    Griskova, Inga; Mørup, Morten; Parnas, Josef

    2007-01-01

    The aim of this study was to investigate, in healthy subjects, the modulation of amplitude and phase precision of the auditory steady-state response (ASSR) to 40 Hz stimulation in two resting conditions varying in the level of arousal. Previously, ASSR measures have shown to be affected......-negative multi-way factorization (NMWF) (Morup et al. in J Neurosci Methods 161:361-368, 2007). The estimates of these measures were subjected to statistical analysis. The amplitude and phase precision of the ASSR were significantly larger during the low arousal state compared to the high arousal condition...

  1. Functional interactions of HIV-infection and methamphetamine dependence during motor programming.

    Science.gov (United States)

    Archibald, Sarah L; Jacobson, Mark W; Fennema-Notestine, Christine; Ogasawara, Miki; Woods, Steven P; Letendre, Scott; Grant, Igor; Jernigan, Terry L

    2012-04-30

    Methamphetamine (METH) dependence is frequently comorbid with HIV infection and both have been linked to alterations of brain structure and function. In a previous study, we showed that the brain volume loss characteristic of HIV infection contrasts with METH-related volume increases in striatum and parietal cortex, suggesting distinct neurobiological responses to HIV and METH (Jernigan et al., 2005). Functional magnetic resonance imaging (fMRI) has the potential to reveal functional interactions between the effects of HIV and METH. In the present study, 50 participants were studied in four groups: an HIV+ group, a recently METH-dependent group, a dually affected group, and a group of unaffected community comparison subjects. An fMRI paradigm consisting of motor sequencing tasks of varying levels of complexity was administered to examine blood oxygenation level dependent (BOLD) changes. Within all groups, activity increased significantly with increasing task complexity in large clusters within sensorimotor and parietal cortex, basal ganglia, cerebellum, and cingulate. The task complexity effect was regressed on HIV status, METH status, and the HIV×METH interaction term in a simultaneous multiple regression. HIV was associated with less complexity-related activation in striatum, whereas METH was associated with less complexity-related activation in parietal regions. Significant interaction effects were observed in both cortical and subcortical regions; and, contrary to expectations, the complexity-related activation was less aberrant in dually affected than in single risk participants, in spite of comparable levels of neurocognitive impairment among the clinical groups. Thus, HIV and METH dependence, perhaps through their effects on dopaminergic systems, may have opposing functional effects on neural circuits involved in motor programming. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Crop yield response to climate change varies with cropping intensity.

    Science.gov (United States)

    Challinor, Andrew J; Parkes, Ben; Ramirez-Villegas, Julian

    2015-04-01

    Projections of the response of crop yield to climate change at different spatial scales are known to vary. However, understanding of the causes of systematic differences across scale is limited. Here, we hypothesize that heterogeneous cropping intensity is one source of scale dependency. Analysis of observed global data and regional crop modelling demonstrate that areas of high vs. low cropping intensity can have systematically different yields, in both observations and simulations. Analysis of global crop data suggests that heterogeneity in cropping intensity is a likely source of scale dependency for a number of crops across the globe. Further crop modelling and a meta-analysis of projected tropical maize yields are used to assess the implications for climate change assessments. The results show that scale dependency is a potential source of systematic bias. We conclude that spatially comprehensive assessments of climate impacts based on yield alone, without accounting for cropping intensity, are prone to systematic overestimation of climate impacts. The findings therefore suggest a need for greater attention to crop suitability and land use change when assessing the impacts of climate change. © 2015 John Wiley & Sons Ltd.

  3. Effects of voluntary exercise on the viability, proliferation and BDNF levels of bone marrow stromal cells in rat pups born from morphine- dependent mothers during pregnancy.

    Science.gov (United States)

    Haydari, Sakineh; Safari, Manouchehr; Zarbakhsh, Sam; Bandegi, Ahmad Reza; Miladi-Gorji, Hossein

    2016-11-10

    This study was designed to investigate whether free access to a running wheel during pregnancy in morphine-dependent mothers would influence the viability, proliferation and BDNF levels of bone marrow stromal cells in rat pups. Pregnant rats were made dependent by chronic administration of morphine in drinking water simultaneously with free access to a running wheel. Male pups are weaned at 21days of birth and their bones marrows were aspirated from the femurs and tibias and also the bone marrow stromal cells (BMSCs) cultured. MTT assay was used to determine cell viability and proliferation rate. The level of BDNF was measured in the supernant of BMSCs culture by ELISA. The sedentary morphine-dependent mothers' pups showed a significant increase in the percentage cell viability and proliferation rate and also a significant decrease in the BDNF protein levels in BMSCs. The rat pups borne from exercising the control and morphine-dependent mothers exhibited an increase in the percentage viability, proliferation rate and BDNF levels of the BMSCs. This study showed that maternal exercise during pregnancy in morphine-dependent and non-dependent mothers, with increasing of BDNF levels increased the proliferation and viability of BMSCs in the rat pups. Also, chronic administration of morphine during pregnancy was able to increase the proliferation and viability of BMSCs in the rat pups. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Chromosome Aberration on High Level Background Natural Radiation Areas

    International Nuclear Information System (INIS)

    Yanti-Lusiyanti; Zubaidah-Alatas

    2001-01-01

    When the body is irradiated, all cells can suffer cytogenetic damage that can be seen as structural damage of chromosome in the lymphocytes. People no matter where they live in world are exposed to background radiation from natural sources both internal and external such as cosmic radiation, terrestrial radiation, cosmogenic radiation radon and thoron. Level of area natural ionizing radiation is varies depending on the altitude, the soil or rock conditions, particular food chains and the building materials and construction features. Level of normal areas of background exposure is annual effective dose 2.4 mSv and the high level areas of background exposure 20 mSv. This paper discuses the frequency of aberration chromosome especially dysenteries in several countries having high level radiation background. It seems that frequency of chromosome aberrations increase, generally with the increase of age of the people and the accumulated dose received. (author)

  5. On exponential stability of bidirectional associative memory neural networks with time-varying delays

    International Nuclear Information System (INIS)

    Park, Ju H.; Lee, S.M.; Kwon, O.M.

    2009-01-01

    For bidirectional associate memory neural networks with time-varying delays, the problems of determining the exponential stability and estimating the exponential convergence rate are investigated by employing the Lyapunov functional method and linear matrix inequality (LMI) technique. A novel criterion for the stability, which give information on the delay-dependent property, is derived. A numerical example is given to demonstrate the effectiveness of the obtained results.

  6. Area, age and gender dependence of the nucleoside system in the brain: a review of current literature.

    Science.gov (United States)

    Kovács, Zsolt; Juhász, Gábor; Palkovits, Miklós; Dobolyi, Arpád; Kékesi, Katalin A

    2011-01-01

    Nucleosides, such as uridine, inosine, guanosine and adenosine, may participate in the regulation of sleep, cognition, memory and nociception, the suppression of seizures, and have also been suggested to play a role in the pathophysiology of some neurodegenerative and neuropsychiatric diseases. Under pathological conditions, levels of nucleosides change extremely in the brain, indicating their participation in the pathophysiology of disorders like Alzheimer's disease, Parkinson's disease and schizophrenia. These findings have resulted in an increasing attention to the roles of nucleosides in the central nervous system. The specific effects of nucleosides depend on the expression of their receptors and transporters in neuronal and glial cells, as well as their extracellular concentrations in the brain. A complex interlinked metabolic network and transporters of nucleosides may balance nucleoside levels in the brain tissue under normal conditions and enable the fine modulation of neuronal and glial processes via nucleoside receptor signaling mechanisms. Brain levels of nucleosides were found to vary when measured in a variety of different brain regions. In addition, nucleoside levels also depend on age and gender. Furthermore, distributions of nucleoside transporters and receptors as well as nucleoside metabolic enzyme activities demonstrate the area, age and gender dependence of the nucleoside system, suggesting different roles of nucleosides in functionally different brain areas. The aim of this review article is to summarize our present knowledge of the area-, age- and gender-dependent distribution of nucleoside levels, nucleoside metabolic enzyme activity, nucleoside receptors and nucleoside transporters in the brain.

  7. Time-dependent changes of levels of endogenous epidermal growth factor in submandibular glands, in kidneys, and in urine in rats during systemic treatment with EGF

    DEFF Research Database (Denmark)

    Vinter-Jensen, Lars; Jørgensen, P E; Thulesen, J

    1998-01-01

    Exogenous EGF influences the levels of endogenous EGF differently in the submandibular glands (SMG) and the kidneys. The aim of the present study was to examine the time-dependent changes in levels of endogenous EGF during 1-4 weeks of EGF treatment.......Exogenous EGF influences the levels of endogenous EGF differently in the submandibular glands (SMG) and the kidneys. The aim of the present study was to examine the time-dependent changes in levels of endogenous EGF during 1-4 weeks of EGF treatment....

  8. Thermoelectric properties control due to doping level and sintering conditions for FGM thermoelectric element

    CERN Document Server

    Kajikawa, T; Shiraishi, K; Ohmori, M; Hirai, T

    1999-01-01

    Thermoelectric performance is determined with three factors, namely, Seebeck coefficient, electrical resistivity and thermal conductivity. For metal and single crystalline semiconductor, those factors have close interrelation each $9 other. However, as the sintered thermoelectric element has various levels of superstructure from macro scale and micro scale in terms of the thermoelectric mechanism, the relationship among them is more complex than that for the $9 melt- grown element, so it is suggested that the control of the temperature dependence of thermoelectric properties is possible to enhance the thermoelectric performance for wide temperature range due to FGM approach. The research $9 objective is to investigate the characteristics of the thermoelectric properties for various doping levels and hot-pressed conditions to make the thermoelectric elements for which the temperature dependence of the performance is $9 controlled due to FGM approach varying the doping levels and sintering conditions. By usage ...

  9. 29 CFR 779.419 - Dependence of the section 7(i) overtime pay exemption upon the level of the employee's “regular...

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Dependence of the section 7(i) overtime pay exemption upon the level of the employee's âregular rateâ of pay. 779.419 Section 779.419 Labor Regulations Relating... Compensated Principally by Commissions § 779.419 Dependence of the section 7(i) overtime pay exemption upon...

  10. Propositional Logics of Dependence

    NARCIS (Netherlands)

    Yang, F.; Väänänen, J.

    2016-01-01

    In this paper, we study logics of dependence on the propositional level. We prove that several interesting propositional logics of dependence, including propositional dependence logic, propositional intuitionistic dependence logic as well as propositional inquisitive logic, are expressively complete

  11. Antibody levels to recombinant VAR2CSA domains vary with Plasmodium falciparum parasitaemia, gestational age, and gravidity, but do not predict pregnancy outcomes.

    Science.gov (United States)

    Fried, Michal; Kurtis, Jonathan D; Swihart, Bruce; Morrison, Robert; Pond-Tor, Sunthorn; Barry, Amadou; Sidibe, Youssoufa; Keita, Sekouba; Mahamar, Almahamoudou; Andemel, Naissem; Attaher, Oumar; Dembele, Adama B; Cisse, Kadidia B; Diarra, Bacary S; Kanoute, Moussa B; Narum, David L; Dicko, Alassane; Duffy, Patrick E

    2018-03-09

    Maternal malaria is a tropical scourge associated with poor pregnancy outcomes. Women become resistant to Plasmodium falciparum pregnancy malaria as they acquire antibodies to the variant surface antigen VAR2CSA, a leading vaccine candidate. Because malaria infection may increase VAR2CSA antibody levels and thereby confound analyses of immune protection, gravidity-dependent changes in antibody levels during and after infection, and the effect of VAR2CSA antibodies on pregnancy outcomes were evaluated. Pregnant women enrolled in a longitudinal cohort study of mother-infant pairs in Ouelessebougou, Mali provided plasma samples at enrollment, gestational week 30-32, and delivery. Antibody levels to VAR2CSA domains were measured using a multiplex bead-based assay. Antibody levels to VAR2CSA were higher in multigravidae than primigravidae. Malaria infection was associated with increased antibody levels to VAR2CSA domains. In primigravidae but not in secundigravidae or multigravidae, antibodies levels sharply declined after an infection. A relationship between any VAR2CSA antibody specificity and protection from adverse pregnancy outcomes was not detected. During malaria infection, primigravidae acquire short-lived antibodies. The lack of an association between VAR2CSA domain antibody reactivity and improved pregnancy outcomes suggests that the recombinant proteins may not present native epitopes targeted by protective antibodies.

  12. Residual strain, scale effects, and time-dependent behaviour at the 240-m level of the underground research laboratory

    International Nuclear Information System (INIS)

    Read, R.S.

    1990-01-01

    Two subhorizontal, orthogonal boreholes were monitored continuously during concentric overcoring at the 240-m level of the Underground Research Laboratory (URL). The magnitude and orientation of principal residual strain components in the near-field stress regime were determined assuming linear elastic behaviour of the rock mass and isotropic conditions. In terms of magnitude, results compared favourably with those from previous tests at the 240-m level. However, orientation results were inconclusive. The effects of scale and borehole orientation relative to the principal stress direction on the results from a modified CSIR triaxial cell overcore test were also investigated; no scale effects were apparent in the experiment, but borehole orientation did affect results. Finally, time-dependent behaviour was detected in the Lac du Bonnet granite, and was monitored between successive overcore tests in one of the boreholes. Results on residual strain, scale effects, and time-dependent behaviour are presented, along with limitations and possible modifications to the testing procedure

  13. Human perception of fear in dogs varies according to experience with dogs.

    Directory of Open Access Journals (Sweden)

    Michele Wan

    Full Text Available To investigate the role of experience in humans' perception of emotion using canine visual signals, we asked adults with various levels of dog experience to interpret the emotions of dogs displayed in videos. The video stimuli had been pre-categorized by an expert panel of dog behavior professionals as showing examples of happy or fearful dog behavior. In a sample of 2,163 participants, the level of dog experience strongly predicted identification of fearful, but not of happy, emotional examples. The probability of selecting the "fearful" category to describe fearful examples increased with experience and ranged from.30 among those who had never lived with a dog to greater than.70 among dog professionals. In contrast, the probability of selecting the "happy" category to describe happy emotional examples varied little by experience, ranging from.90 to.93. In addition, the number of physical features of the dog that participants reported using for emotional interpretations increased with experience, and in particular, more-experienced respondents were more likely to attend to the ears. Lastly, more-experienced respondents provided lower difficulty and higher accuracy self-ratings than less-experienced respondents when interpreting both happy and fearful emotional examples. The human perception of emotion in other humans has previously been shown to be sensitive to individual differences in social experience, and the results of the current study extend the notion of experience-dependent processes from the intraspecific to the interspecific domain.

  14. Quantization of systems with temporally varying discretization. I. Evolving Hilbert spaces

    International Nuclear Information System (INIS)

    Höhn, Philipp A.

    2014-01-01

    A temporally varying discretization often features in discrete gravitational systems and appears in lattice field theory models subject to a coarse graining or refining dynamics. To better understand such discretization changing dynamics in the quantum theory, an according formalism for constrained variational discrete systems is constructed. While this paper focuses on global evolution moves and, for simplicity, restricts to flat configuration spaces R N , a Paper II [P. A. Höhn, “Quantization of systems with temporally varying discretization. II. Local evolution moves,” J. Math. Phys., e-print http://arxiv.org/abs/arXiv:1401.7731 [gr-qc].] discusses local evolution moves. In order to link the covariant and canonical picture, the dynamics of the quantum states is generated by propagators which satisfy the canonical constraints and are constructed using the action and group averaging projectors. This projector formalism offers a systematic method for tracing and regularizing divergences in the resulting state sums. Non-trivial coarse graining evolution moves lead to non-unitary, and thus irreversible, projections of physical Hilbert spaces and Dirac observables such that these concepts become evolution move dependent on temporally varying discretizations. The formalism is illustrated in a toy model mimicking a “creation from nothing.” Subtleties arising when applying such a formalism to quantum gravity models are discussed

  15. Occupation number dependence of molecular energy levels

    International Nuclear Information System (INIS)

    Giambiagi, M.S. de; Giambiagi, M.; Ferreira, R.

    1977-08-01

    The Roothaan expression for the energy of a closed-shell molecular system is generalized in order to apply to open shells. A continuous variation from 0 to 2 is supposed for each level's occupation number, extending to this range tbe correction due to the spurious repulsion appearing in the half-electron method. The characteristic equations of the Xα method are applied to the energy expressions. The one level case is discussed in detail. Ionic and excited states of the 1,3 transbutadiene π system are analyzed

  16. Effects of decontamination at varying contamination levels of Campylobacter jejuni on broiler meat

    DEFF Research Database (Denmark)

    Boysen, Louise; Wechter, Naja Strandby; Rosenquist, Hanne

    2013-01-01

    /sample) or single or few strains of the species (or both) should not be interpreted as a generic result for the species. If inoculation studies cannot be replaced by investigations of naturally contaminated meat, we advise using a mixture of strains found in the production environment at levels as close as possible...... to the natural contamination level....

  17. Sleep Dependent Synaptic Down-Selection (II: Single Neuron Level Benefits for Matching, Selectivity, and Specificity

    Directory of Open Access Journals (Sweden)

    Atif eHashmi

    2013-10-01

    Full Text Available In a companion paper (Nere et al., this volume, we used computer simulations to show that a strategy of activity-dependent, on-line net synaptic potentiation during wake, followed by off-line synaptic depression during sleep, can provide a parsimonious account for several memory benefits of sleep at the systems level, including the consolidation of procedural and declarative memories, gist extraction, and integration of new with old memories. In this paper, we consider the theoretical benefits of this two-step process at the single neuron level and employ the theoretical notion of Matching between brain and environment to measure how this process increases the ability of the neuron to capture regularities in the environment and model them internally. We show that down-selection during sleep is beneficial for increasing or restoring Matching after learning, after integrating new with old memories, and after forgetting irrelevant material. By contrast, alternative schemes, such as additional potentiation in wake, potentiation in sleep, or synaptic renormalization in wake, decrease Matching. We also argue that, by selecting appropriate loops through the brain that tie feedforward synapses with feedback ones in the same dendritic domain, different subsets of neurons can learn to specialize for different contingencies and form sequences of nested perception-action loops. By potentiating such loops when interacting with the environment in wake, and depressing them when disconnected from the environment in sleep, neurons can learn to match the long-term statistical structure of the environment while avoiding spurious modes of functioning and catastrophic interference. Finally, such a two-step process has the additional benefit of desaturating the neuron's ability to learn and of maintaining cellular homeostasis. Thus, sleep-dependent synaptic renormalization offers a parsimonious account for both cellular and systems-level effects of sleep on learning

  18. Quantifying the sensitivity of post-glacial sea level change to laterally varying viscosity

    Science.gov (United States)

    Crawford, Ophelia; Al-Attar, David; Tromp, Jeroen; Mitrovica, Jerry X.; Austermann, Jacqueline; Lau, Harriet C. P.

    2018-05-01

    We present a method for calculating the derivatives of measurements of glacial isostatic adjustment (GIA) with respect to the viscosity structure of the Earth and the ice sheet history. These derivatives, or kernels, quantify the linearised sensitivity of measurements to the underlying model parameters. The adjoint method is used to enable efficient calculation of theoretically exact sensitivity kernels within laterally heterogeneous earth models that can have a range of linear or non-linear viscoelastic rheologies. We first present a new approach to calculate GIA in the time domain, which, in contrast to the more usual formulation in the Laplace domain, is well suited to continuously varying earth models and to the use of the adjoint method. Benchmarking results show excellent agreement between our formulation and previous methods. We illustrate the potential applications of the kernels calculated in this way through a range of numerical calculations relative to a spherically symmetric background model. The complex spatial patterns of the sensitivities are not intuitive, and this is the first time that such effects are quantified in an efficient and accurate manner.

  19. Dose-dependent effects of an immune challenge at both ultimate and proximate levels in Drosophila melanogaster.

    Science.gov (United States)

    Nystrand, M; Dowling, D K

    2014-05-01

    Immune responses are highly dynamic. The magnitude and efficiency of an immune response to a pathogen can change markedly across individuals, and such changes may be influenced by variance in a range of intrinsic (e.g. age, genotype, sex) and external (e.g. abiotic stress, pathogen identity, strain) factors. Life history theory predicts that up-regulation of the immune system will come at a physiological cost, and studies have confirmed that increased investment in immunity can reduce reproductive output and survival. Furthermore, males and females often have divergent reproductive strategies, and this might drive the evolution of sex-specific life history trade-offs involving immunity, and sexual dimorphism in immune responses per se. Here, we employ an experiment design to elucidate dose-dependent and sex-specific responses to exposure to a nonpathogenic immune elicitor at two scales--the 'ultimate' life history and the underlying 'proximate' immune level in Drosophila melanogaster. We found dose-dependent effects of immune challenges on both male and female components of reproductive success, but not on survival, as well as a response in antimicrobial activity. These results indicate that even in the absence of the direct pathogenic effects that are associated with actual disease, individual life histories respond to a perceived immune challenge--but with the magnitude of this response being contingent on the initial dose of exposure. Furthermore, the results indicate that immune responses at the ultimate life history level may indeed reflect underlying processes that occur at the proximate level. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  20. Exploring the level sets of quantum control landscapes

    International Nuclear Information System (INIS)

    Rothman, Adam; Ho, Tak-San; Rabitz, Herschel

    2006-01-01

    A quantum control landscape is defined by the value of a physical observable as a functional of the time-dependent control field E(t) for a given quantum-mechanical system. Level sets through this landscape are prescribed by a particular value of the target observable at the final dynamical time T, regardless of the intervening dynamics. We present a technique for exploring a landscape level set, where a scalar variable s is introduced to characterize trajectories along these level sets. The control fields E(s,t) accomplishing this exploration (i.e., that produce the same value of the target observable for a given system) are determined by solving a differential equation over s in conjunction with the time-dependent Schroedinger equation. There is full freedom to traverse a level set, and a particular trajectory is realized by making an a priori choice for a continuous function f(s,t) that appears in the differential equation for the control field. The continuous function f(s,t) can assume an arbitrary form, and thus a level set generally contains a family of controls, where each control takes the quantum system to the same final target value, but produces a distinct control mechanism. In addition, although the observable value remains invariant over the level set, other dynamical properties (e.g., the degree of robustness to control noise) are not specifically preserved and can vary greatly. Examples are presented to illustrate the continuous nature of level-set controls and their associated induced dynamical features, including continuously morphing mechanisms for population control in model quantum systems

  1. Varying coefficient subdistribution regression for left-truncated semi-competing risks data.

    Science.gov (United States)

    Li, Ruosha; Peng, Limin

    2014-10-01

    Semi-competing risks data frequently arise in biomedical studies when time to a disease landmark event is subject to dependent censoring by death, the observation of which however is not precluded by the occurrence of the landmark event. In observational studies, the analysis of such data can be further complicated by left truncation. In this work, we study a varying co-efficient subdistribution regression model for left-truncated semi-competing risks data. Our method appropriately accounts for the specifical truncation and censoring features of the data, and moreover has the flexibility to accommodate potentially varying covariate effects. The proposed method can be easily implemented and the resulting estimators are shown to have nice asymptotic properties. We also present inference, such as Kolmogorov-Smirnov type and Cramér Von-Mises type hypothesis testing procedures for the covariate effects. Simulation studies and an application to the Denmark diabetes registry demonstrate good finite-sample performance and practical utility of the proposed method.

  2. Influence of Sensory Dependence on Postural Control

    Science.gov (United States)

    Santana, Patricia A.; Mulavara, Ajitkumar P.; Fiedler, Matthew J.

    2011-01-01

    The current project is part of an NSBRI funded project, "Development of Countermeasures to Aid Functional Egress from the Crew Exploration Vehicle Following Long-Duration Spaceflight." The development of this countermeasure is based on the use of imperceptible levels of electrical stimulation to the balance organs of the inner ear to assist and enhance the response of a person s sensorimotor function. These countermeasures could be used to increase an astronaut s re-adaptation rate to Earth s gravity following long-duration space flight. The focus of my project is to evaluate and examine the correlation of sensory preferences for vision and vestibular systems. Disruption of the sensorimotor functions following space flight affects posture, locomotion and spatial orientation tasks in astronauts. The Group Embedded Figures Test (GEFT), the Rod and Frame Test (RFT) and the Computerized Dynamic Posturography Test (CDP) are measurements used to examine subjects visual and vestibular sensory preferences. The analysis of data from these tasks will assist in relating the visual dependence measures recognized in the GEFT and RFT with vestibular dependence measures recognized in the stability measures obtained during CDP. Studying the impact of sensory dependence on the performance in varied tasks will help in the development of targeted countermeasures to help astronauts readapt to gravitational changes after long duration space flight.

  3. Efficiency or speculation? A time-varying analysis of European sovereign debt

    Science.gov (United States)

    Ferreira, Paulo

    2018-01-01

    The outbreak of the Greek debt crisis caused turmoil in European markets and drew attention to the problem of public debt and its consequences. The increase in the return rates of sovereign debts was one of these consequences. However, like any other asset, sovereign debt returns are expected to have a memoryless behaviour. Analysing a total of 15 European countries (Eurozone and non-Eurozone), and applying a time-varying analysis of the Hurst exponent, we found evidence of long-range memory in sovereign bonds. When analysing the spreads between each bond and the German one, it is possible to conclude that Eurozone countries' spreads show more evidence of long-range dependence. Considering the Eurozone countries most affected by the Eurozone crisis, that long-range dependence is more evident, but started before the crisis, which could be interpreted as possible speculation by investors.

  4. Spall behavior of cast iron with varying microstructures

    International Nuclear Information System (INIS)

    Plume, Gifford; Rousseau, Carl-Ernst

    2014-01-01

    The spall strength of cast iron with varying microstructures has been investigated using plate impact at moderate speed. Stress history measurements were made with manganin stress gauges embedded between the back face of the specimen and a low impedance polycarbonate backing. Five separate cast irons were tested. Four of these consisted of gray cast iron with graphite in flake form, with three classified as Type VII A2 and the fourth containing a bimodal distribution of Types VII A4 and VII D8. The fifth casting consisted of ductile cast iron with graphite in nodular form, classified as Type I, size class 5. The spall strength for the Type VII A2 gray cast irons varied between 40 and 370 MPa, and that of the additional gray cast iron, between 410 and 490 MPa. The spall strength of the ductile cast iron fell within the range of 0.94–1.2 GPa. It is shown that the spall strength is linked to the damage level at the spall plane, where an increased level of tensile stress is required to generate higher levels of damage. Post mortem analysis was performed on the recovered samples, revealing the graphite phase to be the primary factor governing the spall fracture of cast irons, where crack nucleation is directly correlated to the debonding of graphite from the metal matrix. The average length of graphite found within a casting is linked to the material's strength, where strength increases as a function of decreasing length. The morphology and mean free path of graphite precipitates further govern the subsequent coalescence of initiated cracks to form a complete fracture plane. In cases where graphite spacing is large, increased energy level is required to complete the fracture process. A secondary factor governing the spall fracture of cast irons has also been linked to the microstructure of the metal matrix, with pearlite yielding higher spall strengths than free ferrite.

  5. Spall behavior of cast iron with varying microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Plume, Gifford; Rousseau, Carl-Ernst, E-mail: rousseau@uri.edu [Mechanical Engineering, University of Rhode Island, 92 Upper College Rd., Kingston, Rhode Island 02881 (United States)

    2014-07-21

    The spall strength of cast iron with varying microstructures has been investigated using plate impact at moderate speed. Stress history measurements were made with manganin stress gauges embedded between the back face of the specimen and a low impedance polycarbonate backing. Five separate cast irons were tested. Four of these consisted of gray cast iron with graphite in flake form, with three classified as Type VII A2 and the fourth containing a bimodal distribution of Types VII A4 and VII D8. The fifth casting consisted of ductile cast iron with graphite in nodular form, classified as Type I, size class 5. The spall strength for the Type VII A2 gray cast irons varied between 40 and 370 MPa, and that of the additional gray cast iron, between 410 and 490 MPa. The spall strength of the ductile cast iron fell within the range of 0.94–1.2 GPa. It is shown that the spall strength is linked to the damage level at the spall plane, where an increased level of tensile stress is required to generate higher levels of damage. Post mortem analysis was performed on the recovered samples, revealing the graphite phase to be the primary factor governing the spall fracture of cast irons, where crack nucleation is directly correlated to the debonding of graphite from the metal matrix. The average length of graphite found within a casting is linked to the material's strength, where strength increases as a function of decreasing length. The morphology and mean free path of graphite precipitates further govern the subsequent coalescence of initiated cracks to form a complete fracture plane. In cases where graphite spacing is large, increased energy level is required to complete the fracture process. A secondary factor governing the spall fracture of cast irons has also been linked to the microstructure of the metal matrix, with pearlite yielding higher spall strengths than free ferrite.

  6. Fires in Seasonally Dry Tropical Forest: Testing the Varying Constraints Hypothesis across a Regional Rainfall Gradient.

    Science.gov (United States)

    Mondal, Nandita; Sukumar, Raman

    2016-01-01

    The "varying constraints hypothesis" of fire in natural ecosystems postulates that the extent of fire in an ecosystem would differ according to the relative contribution of fuel load and fuel moisture available, factors that vary globally along a spatial gradient of climatic conditions. We examined if the globally widespread seasonally dry tropical forests (SDTFs) can be placed as a single entity in this framework by analyzing environmental influences on fire extent in a structurally diverse SDTF landscape in the Western Ghats of southern India, representative of similar forests in monsoonal south and southeast Asia. We used logistic regression to model fire extent with factors that represent fuel load and fuel moisture at two levels-the overall landscape and within four defined moisture regimes (between 700 and1700 mm yr-1)-using a dataset of area burnt and seasonal rainfall from 1990 to 2010. The landscape scale model showed that the extent of fire in a given year within this SDTF is dependent on the combined interaction of seasonal rainfall and extent burnt the previous year. Within individual moisture regimes the relative contribution of these factors to the annual extent burnt varied-early dry season rainfall (i.e., fuel moisture) was the predominant factor in the wettest regime, while wet season rainfall (i.e., fuel load) had a large influence on fire extent in the driest regime. Thus, the diverse structural vegetation types associated with SDTFs across a wide range of rainfall regimes would have to be examined at finer regional or local scales to understand the specific environmental drivers of fire. Our results could be extended to investigating fire-climate relationships in STDFs of monsoonal Asia.

  7. Information Superiority and Game Theory: The Value of Varying Levels of Information

    National Research Council Canada - National Science Library

    McIntosh, Gary

    2002-01-01

    .... This thesis examines how various levels of information and information superiority affect strategy choices and decision-making in determining the payoff value for opposing forces in a classic zero-sum two-sided contest...

  8. Hemispheric lateralization for early auditory processing of lexical tones: dependence on pitch level and pitch contour.

    Science.gov (United States)

    Wang, Xiao-Dong; Wang, Ming; Chen, Lin

    2013-09-01

    In Mandarin Chinese, a tonal language, pitch level and pitch contour are two dimensions of lexical tones according to their acoustic features (i.e., pitch patterns). A change in pitch level features a step change whereas that in pitch contour features a continuous variation in voice pitch. Currently, relatively little is known about the hemispheric lateralization for the processing of each dimension. To address this issue, we made whole-head electrical recordings of mismatch negativity in native Chinese speakers in response to the contrast of Chinese lexical tones in each dimension. We found that pre-attentive auditory processing of pitch level was obviously lateralized to the right hemisphere whereas there is a tendency for that of pitch contour to be lateralized to the left. We also found that the brain responded faster to pitch level than to pitch contour at a pre-attentive stage. These results indicate that the hemispheric lateralization for early auditory processing of lexical tones depends on the pitch level and pitch contour, and suggest an underlying inter-hemispheric interactive mechanism for the processing. © 2013 Elsevier Ltd. All rights reserved.

  9. Vector-field statistics for the analysis of time varying clinical gait data.

    Science.gov (United States)

    Donnelly, C J; Alexander, C; Pataky, T C; Stannage, K; Reid, S; Robinson, M A

    2017-01-01

    In clinical settings, the time varying analysis of gait data relies heavily on the experience of the individual(s) assessing these biological signals. Though three dimensional kinematics are recognised as time varying waveforms (1D), exploratory statistical analysis of these data are commonly carried out with multiple discrete or 0D dependent variables. In the absence of an a priori 0D hypothesis, clinicians are at risk of making type I and II errors in their analyis of time varying gait signatures in the event statistics are used in concert with prefered subjective clinical assesment methods. The aim of this communication was to determine if vector field waveform statistics were capable of providing quantitative corroboration to practically significant differences in time varying gait signatures as determined by two clinically trained gait experts. The case study was a left hemiplegic Cerebral Palsy (GMFCS I) gait patient following a botulinum toxin (BoNT-A) injection to their left gastrocnemius muscle. When comparing subjective clinical gait assessments between two testers, they were in agreement with each other for 61% of the joint degrees of freedom and phases of motion analysed. For tester 1 and tester 2, they were in agreement with the vector-field analysis for 78% and 53% of the kinematic variables analysed. When the subjective analyses of tester 1 and tester 2 were pooled together and then compared to the vector-field analysis, they were in agreement for 83% of the time varying kinematic variables analysed. These outcomes demonstrate that in principle, vector-field statistics corroborates with what a team of clinical gait experts would classify as practically meaningful pre- versus post time varying kinematic differences. The potential for vector-field statistics to be used as a useful clinical tool for the objective analysis of time varying clinical gait data is established. Future research is recommended to assess the usefulness of vector-field analyses

  10. Varying coefficients model with measurement error.

    Science.gov (United States)

    Li, Liang; Greene, Tom

    2008-06-01

    We propose a semiparametric partially varying coefficient model to study the relationship between serum creatinine concentration and the glomerular filtration rate (GFR) among kidney donors and patients with chronic kidney disease. A regression model is used to relate serum creatinine to GFR and demographic factors in which coefficient of GFR is expressed as a function of age to allow its effect to be age dependent. GFR measurements obtained from the clearance of a radioactively labeled isotope are assumed to be a surrogate for the true GFR, with the relationship between measured and true GFR expressed using an additive error model. We use locally corrected score equations to estimate parameters and coefficient functions, and propose an expected generalized cross-validation (EGCV) method to select the kernel bandwidth. The performance of the proposed methods, which avoid distributional assumptions on the true GFR and residuals, is investigated by simulation. Accounting for measurement error using the proposed model reduced apparent inconsistencies in the relationship between serum creatinine and GFR among different clinical data sets derived from kidney donor and chronic kidney disease source populations.

  11. Arterial Spin Labeling and Blood Oxygen Level-Dependent MRI Cerebrovascular Reactivity in Cerebrovascular Disease

    DEFF Research Database (Denmark)

    Smeeing, Diederik P J; Hendrikse, Jeroen; Petersen, Esben T

    2016-01-01

    BACKGROUND: The cerebrovascular reactivity (CVR) results of blood oxygen level-dependent (BOLD) and arterial spin labeling (ASL) MRI studies performed in patients with cerebrovascular disease (steno-occlusive vascular disease or stroke) were systematically reviewed. SUMMARY: Thirty-one articles...... found a significant lower ASL CVR in the ipsilateral hemispheres of patients compared to controls. KEY MESSAGES: This review brings support for a reduced BOLD and ASL CVR in the ipsilateral hemisphere of patients with cerebrovascular disease. We suggest that future studies will be performed in a uniform...... way so reference values can be established and could be used to guide treatment decisions in patients with cerebrovascular disease....

  12. Passivity of memristive BAM neural networks with leakage and additive time-varying delays

    Science.gov (United States)

    Wang, Weiping; Wang, Meiqi; Luo, Xiong; Li, Lixiang; Zhao, Wenbing; Liu, Linlin; Ping, Yuan

    2018-02-01

    This paper investigates the passivity of memristive bidirectional associate memory neural networks (MBAMNNs) with leakage and additive time-varying delays. Based on some useful inequalities and appropriate Lyapunov-Krasovskii functionals (LKFs), several delay-dependent conditions for passivity performance are obtained in linear matrix inequalities (LMIs). Moreover, the leakage delays as well as additive delays are considered separately. Finally, numerical simulations are provided to demonstrate the feasibility of the theoretical results.

  13. A varying-α brane world cosmology

    International Nuclear Information System (INIS)

    Youm, Donam

    2001-08-01

    We study the brane world cosmology in the RS2 model where the electric charge varies with time in the manner described by the varying fine-structure constant theory of Bekenstein. We map such varying electric charge cosmology to the dual variable-speed-of-light cosmology by changing system of units. We comment on cosmological implications for such cosmological models. (author)

  14. Simulation of design dependent failure exposure levels for CMOS ICs

    International Nuclear Information System (INIS)

    Kaul, N.; Bhuva, B.L.; Rangavajjhala, V.; van der Molen, H.; Kerns, S.E.

    1990-01-01

    The total dose exposure of CMOS ICs introduces bias-dependent parameter shifts in individual devices. The bias dependency of individual parameter shifts of devices cause different designs to behave differently under identical testing conditions. This paper studies the effect of design and bias on the radiation tolerance of ICs and presents an automated design tool that produces different designs for a logic function, and presents important parameters of each design to circuit designer for trade off analysis

  15. Observation of time-varying photoconductivity and persistent photoconductivity in porous silicon

    DEFF Research Database (Denmark)

    Frello, T.; Veje, E.; Leistiko, Otto

    1996-01-01

    We have observed time-varying photoconductivity and persistent photoconductivity in porous silicon, both with time-evolution scales of the order of several minutes or hours. The time evolutions depend on the wavelength and the intensity of the illuminating light. The data indicate the presence...... of at least two competing mechanisms, one is tentatively related to photoinduced creation of charge carriers in the silicon substrate followed by diffusion into the porous silicon layer, and the other is tentatively related to desorption of hydrogen from the porous silicon. ©1996 American Institute of Physics....

  16. Selective and context-dependent effects of chemical stress across trophic levels at the basis of marine food webs.

    Science.gov (United States)

    Mensens, Christoph; De Laender, Frederik; Janssen, Colin R; Rivera, Frances Camille; Sabbe, Koen; De Troch, Marleen

    2018-04-26

    Human activities increasingly impact the functioning of marine food webs, but anthropogenic stressors are seldom included in ecological study designs. Diet quality, as distinct from just diet quantity, has moreover rarely been highlighted in food web studies in a stress context. We measured the effects of metal and pesticide stress (copper and atrazine) on the contribution of a benthic intertidal diatom community to two processes that are key to the functioning of intertidal systems: biomass (diet quantity) and lipid (diet quality) production. We then examined if stressors affected diatom functioning by selectively targeting the species contributing most to functioning (selective stress effects) or by changing the species' functional contribution (context-dependent effects). Finally, we tested if stress-induced changes in diet quality altered the energy flow to the diatoms' main grazers (harpacticoid copepods). Diatom diet quantity was reduced by metal stress but not by low pesticide levels due to the presence of an atrazine-tolerant, mixotrophic species. Selective effects of the pesticide reduced diatom diet quality by 60% and 75% at low and high pesticide levels respectively, by shifting diatom community structure from dominance by lipid-rich species toward dominance by an atrazine-tolerant, but lipid-poor, species. Context-dependent effects did not affect individual diatom lipid content at low levels of both stressors, but caused diatoms to lose 40% of their lipids at high copper stress. Stress-induced changes in diet quality predicted the energy flow from the diatoms to their copepod consumers, which lost half of their lipids when feeding on diatoms grown under low and high pesticide and high metal stress. Selective pesticide effects were a more important threat for trophic energy transfer than context-dependent effects of both stressors, with shifts in diatom community structure affecting the energy flow to their copepod grazers at stress levels where no

  17. Time varying, multivariate volume data reduction

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, James P [Los Alamos National Laboratory; Fout, Nathaniel [UC DAVIS; Ma, Kwan - Liu [UC DAVIS

    2010-01-01

    Large-scale supercomputing is revolutionizing the way science is conducted. A growing challenge, however, is understanding the massive quantities of data produced by large-scale simulations. The data, typically time-varying, multivariate, and volumetric, can occupy from hundreds of gigabytes to several terabytes of storage space. Transferring and processing volume data of such sizes is prohibitively expensive and resource intensive. Although it may not be possible to entirely alleviate these problems, data compression should be considered as part of a viable solution, especially when the primary means of data analysis is volume rendering. In this paper we present our study of multivariate compression, which exploits correlations among related variables, for volume rendering. Two configurations for multidimensional compression based on vector quantization are examined. We emphasize quality reconstruction and interactive rendering, which leads us to a solution using graphics hardware to perform on-the-fly decompression during rendering. In this paper we present a solution which addresses the need for data reduction in large supercomputing environments where data resulting from simulations occupies tremendous amounts of storage. Our solution employs a lossy encoding scheme to acrueve data reduction with several options in terms of rate-distortion behavior. We focus on encoding of multiple variables together, with optional compression in space and time. The compressed volumes can be rendered directly with commodity graphics cards at interactive frame rates and rendering quality similar to that of static volume renderers. Compression results using a multivariate time-varying data set indicate that encoding multiple variables results in acceptable performance in the case of spatial and temporal encoding as compared to independent compression of variables. The relative performance of spatial vs. temporal compression is data dependent, although temporal compression has the

  18. Discrete-Time Sliding-Mode Control of Uncertain Systems with Time-Varying Delays via Descriptor Approach

    Directory of Open Access Journals (Sweden)

    Maode Yan

    2008-01-01

    Full Text Available This paper considers the problem of robust discrete-time sliding-mode control (DT-SMC design for a class of uncertain linear systems with time-varying delays. By applying a descriptor model transformation and Moon's inequality for bounding cross terms, a delay-dependent sufficient condition for the existence of stable sliding surface is given in terms of linear matrix inequalities (LMIs. Based on this existence condition, the synthesized sliding mode controller can guarantee the sliding-mode reaching condition of the specified discrete-time sliding surface for all admissible uncertainties and time-varying delays. An illustrative example verifies the effectiveness of the proposed method.

  19. Low-level lasers alter mRNA levels from traditional reference genes used in breast cancer cells

    Science.gov (United States)

    Teixeira, A. F.; Canuto, K. S.; Rodrigues, J. A.; Fonseca, A. S.; Mencalha, A. L.

    2017-07-01

    Cancer is among the leading causes of mortality worldwide, increasing the importance of treatment development. Low-level lasers are used in several diseases, but some concerns remains on cancers. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) is a technique used to understand cellular behavior through quantification of mRNA levels. Output data from target genes are commonly relative to a reference that cannot vary according to treatment. This study evaluated reference genes levels from MDA-MB-231 cells exposed to red or infrared lasers at different fluences. Cultures were exposed to red and infrared lasers, incubated (4 h, 37 °C), total RNA was extracted and cDNA synthesis was performed to evaluate mRNA levels from ACTB, GUSB and TRFC genes by RT-qPCR. Specific amplification was verified by melting curves and agarose gel electrophoresis. RefFinder enabled data analysis by geNorm, NormFinder and BestKeeper. Specific amplifications were obtained and, although mRNA levels from ACTB, GUSB or TRFC genes presented no significant variation through traditional statistical analysis, Excel-based tools revealed that the use of these reference genes are dependent of laser characteristics. Our data showed that exposure to low-level red and infrared lasers at different fluences alter the mRNA levels from ACTB, GUSB and TRFC in MDA-MB-231 cells.

  20. Estimation of Time-Varying Coherence and Its Application in Understanding Brain Functional Connectivity

    Directory of Open Access Journals (Sweden)

    Cheng Liu

    2010-01-01

    Full Text Available Time-varying coherence is a powerful tool for revealing functional dynamics between different regions in the brain. In this paper, we address ways of estimating evolutionary spectrum and coherence using the general Cohen's class distributions. We show that the intimate connection between the Cohen's class-based spectra and the evolutionary spectra defined on the locally stationary time series can be linked by the kernel functions of the Cohen's class distributions. The time-varying spectra and coherence are further generalized with the Stockwell transform, a multiscale time-frequency representation. The Stockwell measures can be studied in the framework of the Cohen's class distributions with a generalized frequency-dependent kernel function. A magnetoencephalography study using the Stockwell coherence reveals an interesting temporal interaction between contralateral and ipsilateral motor cortices under the multisource interference task.

  1. Velocity form of the Kohn-Sham frequency-dependent polarizability equations

    International Nuclear Information System (INIS)

    Bartolotti, L.J.

    1987-01-01

    A single equation is derived for the determination of the first-order correction to the frequency-dependent density, due to the perturbation of a time-varying electric field. This new expression for the first-order correction to the frequency-dependent Kohn-Sham amplitudes depends explicitly upon the velocity form of the dipole-moment operator and the square of the Kohn-Sham Hamiltonian

  2. Hierarchical Distributed-Lag Models: Exploring Varying Geographic Scale and Magnitude in Associations Between the Built Environment and Health.

    Science.gov (United States)

    Baek, Jonggyu; Sanchez-Vaznaugh, Emma V; Sánchez, Brisa N

    2016-03-15

    It is well known that associations between features of the built environment and health depend on the geographic scale used to construct environmental attributes. In the built environment literature, it has long been argued that geographic scales may vary across study locations. However, this hypothesized variation has not been systematically examined due to a lack of available statistical methods. We propose a hierarchical distributed-lag model (HDLM) for estimating the underlying overall shape of food environment-health associations as a function of distance from locations of interest. This method enables indirect assessment of relevant geographic scales and captures area-level heterogeneity in the magnitudes of associations, along with relevant distances within areas. The proposed model was used to systematically examine area-level variation in the association between availability of convenience stores around schools and children's weights. For this case study, body mass index (weight kg)/height (m)2) z scores (BMIz) for 7th grade children collected via California's 2001-2009 FitnessGram testing program were linked to a commercial database that contained locations of food outlets statewide. Findings suggested that convenience store availability may influence BMIz only in some places and at varying distances from schools. Future research should examine localized environmental or policy differences that may explain the heterogeneity in convenience store-BMIz associations. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Illuminating a neglected clinical issue: societal costs of interpersonal dependency and dependent personality disorder.

    Science.gov (United States)

    Bornstein, Robert F

    2012-07-01

    To determine the degree to which patients with high levels of trait dependency or dependent personality disorder (DPD) engage in behaviors that harm themselves and others (e.g., domestic violence, child abuse). Six domains of literature were reviewed: (a) dependency as a risk factor for physical illness; (b) health care utilization and expenditures; (c) global and domain-specific functional impairment; (d) violence toward others; (e) victimization by others; and (f) self-harm. High levels of trait dependency and DPD are associated with elevated risk for physical illness, partner and child abuse, and suicidality, as well as with high levels of functional impairment and increased health care expenditure. Contrary to clinical lore, trait dependency and DPD are associated with behaviors that lead to myriad negative consequences for the dependent person, those close to them, and society as a whole. These patterns have noteworthy implications for assessment and treatment of dependent patients and suggest that DPD should be included as a diagnostic category in the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition. © 2012 Wiley Periodicals, Inc.

  4. Scale effects on spatially varying relationships between urban landscape patterns and water quality.

    Science.gov (United States)

    Sun, Yanwei; Guo, Qinghai; Liu, Jian; Wang, Run

    2014-08-01

    Scientific interpretation of the relationships between urban landscape patterns and water quality is important for sustainable urban planning and watershed environmental protection. This study applied the ordinary least squares regression model and the geographically weighted regression model to examine the spatially varying relationships between 12 explanatory variables (including three topographical factors, four land use parameters, and five landscape metrics) and 15 water quality indicators in watersheds of Yundang Lake, Maluan Bay, and Xinglin Bay with varying levels of urbanization in Xiamen City, China. A local and global investigation was carried out at the watershed-level, with 50 and 200 m riparian buffer scales. This study found that topographical features and landscape metrics are the dominant factors of water quality, while land uses are too weak to be considered as a strong influential factor on water quality. Such statistical results may be related with the characteristics of land use compositions in our study area. Water quality variations in the 50 m buffer were dominated by topographical variables. The impact of landscape metrics on water quality gradually strengthen with expanding buffer zones. The strongest relationships are obtained in entire watersheds, rather than in 50 and 200 m buffer zones. Spatially varying relationships and effective buffer zones were verified in this study. Spatially varying relationships between explanatory variables and water quality parameters are more diversified and complex in less urbanized areas than in highly urbanized areas. This study hypothesizes that all these varying relationships may be attributed to the heterogeneity of landscape patterns in different urban regions. Adjustment of landscape patterns in an entire watershed should be the key measure to successfully improving urban lake water quality.

  5. Distribution of toenail selenium levels in young adult Caucasians and African Americans in the United States: The CARDIA Trace Element Study

    International Nuclear Information System (INIS)

    Xun, Pengcheng; Bujnowski, Deborah; Liu, Kiang; Steve Morris, J.; Guo, Zhongqin; He, Ka

    2011-01-01

    Background: Data on selenium (Se) levels in American young adults, especially in African Americans, are lacking. Objective: This study presented toenail Se distributions in American young adults of both genders, including both Caucasians and African Americans; and explored potential predictors of toenail Se levels. Data and methods: Data from the Coronary Artery Risk Development in Young Adults study among 4252 American young adults, aged 20-32 in 1987 was used to examine toenail Se levels by instrumental neutron-activation analysis. The distribution of Se levels was described and multivariable linear regression was used to examine potential modifiers of toenail Se concentration within ethnicity-gender subgroups. Results: The geometric mean of toenail Se in this cohort was 0.844 μg/g (95% CI, 0.840-0.849 μg/g) and the median was 0.837 μg/g (95% CI, 0.833-0.844 μg/g). Median levels from lowest to highest quintile were 0.691, 0.774, 0.838, 0.913 and 1.037 μg/g. Se levels varied geographically, and were generally in accordance with its concentrations in local soil. Males, African Americans, current smokers, heavy drinkers and less educated participants were more likely to have low Se levels. Conclusion: This study suggests that toenail Se levels vary geographically depending on soil Se concentrations. In addition to gender, ethnicity and education level, smoking status and alcohol consumption are two important indicators of Se status since they are modifiable lifestyle factors. Findings from this study might aid public health professionals in identifying people at relatively high or low Se levels, so that chronic disease prevention efforts can be directed toward these subgroups. - Research highlights: → Average of toenail Se levels in this cohort was 0.844 μg/g (95% CI, 0.840-0.849 μg/g). → Toenail Se levels vary geographically depending on soil Se concentrations. → Males, African Americans and less educated participants have low Se levels. → Smoking

  6. Motivation for Using Generalized Geometry in the Time Dependent Transport Code TDKENO

    Energy Technology Data Exchange (ETDEWEB)

    Dustin Popp; Zander Mausolff; Sedat Goluoglu

    2016-04-01

    We are proposing to use the code, TDKENO, to model TREAT. TDKENO solves the time dependent, three dimensional Boltzmann transport equation with explicit representation of delayed neutrons. Instead of directly integrating this equation, the neutron flux is factored into two components – a rapidly varying amplitude equation and a slowly varying shape equation and each is solved separately on different time scales. The shape equation is solved using the 3D Monte Carlo transport code KENO, from Oak Ridge National Laboratory’s SCALE code package. Using the Monte Carlo method to solve the shape equation is still computationally intensive, but the operation is only performed when needed. The amplitude equation is solved deterministically and frequently, so the solution gives an accurate time-dependent solution without having to repeatedly We have modified TDKENO to incorporate KENO-VI so that we may accurately represent the geometries within TREAT. This paper explains the motivation behind using generalized geometry, and provides the results of our modifications. TDKENO uses the Improved Quasi-Static method to accomplish this. In this method, the neutron flux is factored into two components. One component is a purely time-dependent and rapidly varying amplitude function, which is solved deterministically and very frequently (small time steps). The other is a slowly varying flux shape function that weakly depends on time and is only solved when needed (significantly larger time steps).

  7. Human reliability analysis of dependent events

    International Nuclear Information System (INIS)

    Swain, A.D.; Guttmann, H.E.

    1977-01-01

    In the human reliability analysis in WASH-1400, the continuous variable of degree of interaction among human events was approximated by selecting four points on this continuum to represent the entire continuum. The four points selected were identified as zero coupling (i.e., zero dependence), complete coupling (i.e., complete dependence), and two intermediate points--loose coupling (a moderate level of dependence) and tight coupling (a high level of dependence). The paper expands the WASH-1400 treatment of common mode failure due to the interaction of human activities. Mathematical expressions for the above four levels of dependence are derived for parallel and series systems. The psychological meaning of each level of dependence is illustrated by examples, with probability tree diagrams to illustrate the use of conditional probabilities resulting from the interaction of human actions in nuclear power plant tasks

  8. Propagation of a laser beam in a time-varying waveguide

    International Nuclear Information System (INIS)

    Chapman, J.M.; Kevorkian, J.

    1978-01-01

    The propagation of an axisymmetric laser beam in a plasma column having a radially parabolic electron density distribution is examined. First, an extended paraxial procedure is developed for the case of an axially uniform waveguide. It is shown that the essential feature of an alternate focusing and defocusing beam is retained, but that the intensity distribution is cumulatively modified at the foci and at the outer portions of the beam as compared to that of the paraxial case. Second, some general features of paraxial beam propagation are examined for the case of axially varying waveguides. Finally, laser plasma coupling is examined for the case when laser heating generates a density distribution that is radially parabolic near the axis and when the energy absorbed over a focal length of a plasma lens is small. It is shown that stable or unstable beam propagation depends upon the relative magnitude of the density fluctuations which exist in the axial variation of the waveguides as a result of laser heating. When the fluctuations are small, the propagation is stable, and a simple algebraic expression is obtained which relates the beam diameter to the axially slow averaged variation in the waveguide. When the fluctuations are large, the propagation stability can be determined only by consistently combining plasma dynamics and beam propagation to interrelate the axial variation of the beam to that of the waveguide. In this case of beam propagation in a time-varying waveguide, it is shown that the global stability of the propagation depends upon the initial fluctuation growth rate compared to the initial time rate of change in the radial curvature of the waveguide

  9. Gay-Straight Alliances vary on dimensions of youth socializing and advocacy: factors accounting for individual and setting-level differences.

    Science.gov (United States)

    Poteat, V Paul; Scheer, Jillian R; Marx, Robert A; Calzo, Jerel P; Yoshikawa, Hirokazu

    2015-06-01

    Gay-Straight Alliances (GSAs) are school-based youth settings that could promote health. Yet, GSAs have been treated as homogenous without attention to variability in how they operate or to how youth are involved in different capacities. Using a systems perspective, we considered two primary dimensions along which GSAs function to promote health: providing socializing and advocacy opportunities. Among 448 students in 48 GSAs who attended six regional conferences in Massachusetts (59.8 % LGBQ; 69.9 % White; 70.1 % cisgender female), we found substantial variation among GSAs and youth in levels of socializing and advocacy. GSAs were more distinct from one another on advocacy than socializing. Using multilevel modeling, we identified group and individual factors accounting for this variability. In the socializing model, youth and GSAs that did more socializing activities did more advocacy. In the advocacy model, youth who were more actively engaged in the GSA as well as GSAs whose youth collectively perceived greater school hostility and reported greater social justice efficacy did more advocacy. Findings suggest potential reasons why GSAs vary in how they function in ways ranging from internal provisions of support, to visibility raising, to collective social change. The findings are further relevant for settings supporting youth from other marginalized backgrounds and that include advocacy in their mission.

  10. An fMRI study of joint action – varying levels of cooperation correlates with activity in sensorimotor control, but not mentalization, networks

    Directory of Open Access Journals (Sweden)

    Thierry eChaminade

    2012-06-01

    Full Text Available As social agents, humans continuously interact with with the people around them. Here, motor cooperation was investigated by designing a situation in which pairs of participants, one being scanned with fMRI, controlled jointly a visually presented object with joystick movements. The object oscillated dynamically along two dimensions, shades of pink and width of gratings, corresponding to the two cardinal directions of joystick movements. While the overall control of each participant on the object was kept constant, the amount of cooperation along the two dimensions varied along four levels, from no (each participant controlled exclusively one dimension to full (each participant controlled half of each dimension cooperation. Increasing cooperation correlated with BOLD signal in the left parietal operculum and anterior cingulate cortex, while decreasing cooperation correlated with activity in the right inferior frontal and superior temporal gyri, in the intraparietal sulci and inferior temporal gyrii bilaterally, and in the dorsomedial prefrontal cortex. As joint control improved with the level of cooperation, we assessed the brain responses correlating with joint performance, and found that activity in most of the areas associated with levels of cooperation also correlated with the joint performance. The only brain area found exclusively in the negative correlation with cooperation was within the posterior region of the rostral medial frontal cortex, involved in the monitoring of action outcome. We therefore propose that this region responds to the predictability of visual feedback given the motor commands, which is maximal when participants do not cooperate as they fully control one dimension. Our results therefore indicate that, in the current experimental paradigm, the level of cooperation affects sensorimotor processing, but not mentalizing. Altogether, humans do not need to have access to others’ intentional states to cooperate on a joint

  11. A STUDY OF DISPLACEMENT-LEVEL DEPENDENCY OF VERTICAL STIFFNESS OF PILE - COMPARISONS BETWEEN STATIC LOADING TEST AND MEASUREMENTS DURING TRAIN PASSING -

    Science.gov (United States)

    Nihei, Tatsuya; Nishioka, Hidetoshi; Kawamura, Chikara; Nishimura, Masahiro; Edamatsu, Masayuki; Koda, Masayuki

    In order to introduce the performance based design of pile foundation, vertical stiffness of pile is one of the important design factors. Although it had been es timated the vertical stiffness of pile had the displacement-level dependency, it had been not clarified. We compared the vertical stiffness of pile measured by two loading conditions at pile foundation of the railway viaduct. Firstly, we measured the vertical stiffness at static loading test under construction of the viaduct. Secondly, we measured the vertical stiffness at the time of train passing. So, we recognized that the extrapolation of the displacement level dependency in static loading test could evaluate the vertical stiffness of pile during train passing.

  12. The Scalp Time-Varying Networks of N170: Reference, Latency, and Information Flow

    Directory of Open Access Journals (Sweden)

    Yin Tian

    2018-04-01

    Full Text Available Using the scalp time-varying network method, the present study is the first to investigate the temporal influence of the reference on N170, a negative event-related potential component (ERP appeared about 170 ms that is elicited by facial recognition, in the network levels. Two kinds of scalp electroencephalogram (EEG references, namely, AR (average of all recording channels and reference electrode standardization technique (REST, were comparatively investigated via the time-varying processing of N170. Results showed that the latency and amplitude of N170 were significantly different between REST and AR, with the former being earlier and smaller. In particular, the information flow from right temporal-parietal P8 to left P7 in the time-varying network was earlier in REST than that in AR, and this phenomenon was reproduced by simulation, in which the performance of REST was closer to the true case at source level. These findings indicate that reference plays a crucial role in ERP data interpretation, and importantly, the newly developed approximate zero-reference REST would be a superior choice for precise evaluation of the scalp spatio-temporal changes relating to various cognitive events.

  13. The Effectiveness of Experimental Diet with Varying Levels of Papain on The Growth Performance, Survival Rate and Feed Utilization of Keureling Fish (Tor tambra

    Directory of Open Access Journals (Sweden)

    Zainal Abidin Muchlisin

    2016-09-01

    Full Text Available The objective of present study was to determine the optimum level of papain in the diet of keureling fish (Tor tambra. The complete random design was utilized in this study. Six levels of papain dosage were tested in triplicates, i.e. 0 (control; 17.5 mg kg-1,  20.0 mg kg-1, 22.5 mg kg-1, 25.0 mg kg-1 and 27.5 mg kg-1 of feed. The experimental fish were fed the experimental diet two times a day at 8 AM and 5 PM at feeding level of 5% body weight for 90 days. The Anova test result showed that papain enzyme  gave a significant effect on the weight gain, daily growth rate, specific growth rate, survival rate, feed conversion ratio and feed efficiency (P<0.05. The Duncan multi-rage test result showed that the higher values for all measured parameters were obtained at the dosage of 27.5 mg kg-1. Therefore, it is concluded that the optimum dosage of papain enzyme for keureling fish was 27.5 mg kg-1 of feed.How to CiteMuchlisin, Z. A., Afrido, F., Murda, T., Fadli, N., Muhammadar, A. A., Jalil, Z., & Yulvizar, C. (2016. The Effectiveness of Experimental Diet with Varying Levels of Papain on The Growth Performance, Survival Rate and Feed Utilization of Keureling Fish (Tor tambra. Biosaintifika: Journal of Biology & Biology Education, 8(2, 172-177.

  14. Time-Varying Periodicity in Intraday Volatility

    DEFF Research Database (Denmark)

    Andersen, Torben Gustav; Thyrsgaard, Martin; Todorov, Viktor

    We develop a nonparametric test for deciding whether return volatility exhibits time-varying intraday periodicity using a long time-series of high-frequency data. Our null hypothesis, commonly adopted in work on volatility modeling, is that volatility follows a stationary process combined...... with a constant time-of-day periodic component. We first construct time-of-day volatility estimates and studentize the high-frequency returns with these periodic components. If the intraday volatility periodicity is invariant over time, then the distribution of the studentized returns should be identical across...... with estimating volatility moments through their sample counterparts. Critical values are computed via easy-to-implement simulation. In an empirical application to S&P 500 index returns, we find strong evidence for variation in the intraday volatility pattern driven in part by the current level of volatility...

  15. Uroguanylin levels in intestine and plasma are regulated by nutritional status in a leptin-dependent manner.

    Science.gov (United States)

    Folgueira, C; Sanchez-Rebordelo, E; Barja-Fernandez, S; Leis, R; Tovar, S; Casanueva, F F; Dieguez, C; Nogueiras, R; Seoane, L M

    2016-03-01

    Uroguanylin (UGN) is a 16 amino acid peptide produced mainly by intestinal epithelial cells. Nutrients intake increases circulating levels of prouroguanylin that is processed and converted to UGN to activate the guanylyl cyclase 2C receptor (GUCY2C). Given that the UGN-GUCY2C system has been proposed as a novel gut-brain endocrine axis regulating energy balance, the aim of the present study was to investigate the regulation of UGN protein levels in duodenum and circulating levels in lean and obese mice under different nutritional conditions and its potential interaction with leptin. Swiss, C57BL/6 wild-type and ob/ob male adult mice under different nutritional conditions were used: fed ad libitum standard diet (control); 48 h fasting (fasted); 48 h fasting followed by 24 h of feeding (refed); and fed high-fat diet (45 %) during 10 weeks. In addition, peripheral leptin administration was performed. Intestinal uroguanylin expression was studied by Western blot analysis; plasma levels were measured by ELISA. Food deprivation significantly reduced plasma UGN levels, which were correlated with the lower protein levels of UGN in duodenum. These effects were reverted after refeeding and leptin challenge. Consistently, in ob/ob mice UGN expression was decreased, whereas leptin treatment up-regulated UGN levels in duodenum in these genetically modified mice compared to WT. Diet-induced obese mice displayed increased UGN levels in intestine and plasma in comparison with lean mice. Our findings suggest that UGN levels are correlated with energy balance status and that the regulation of UGN by nutritional status is leptin-dependent.

  16. Energy dependence of commercially available diode detectors for in-vivo dosimetry

    International Nuclear Information System (INIS)

    Saini, Amarjit S.; Zhu, Timothy C.

    2007-01-01

    The energy dependence of commercially available diode detectors was measured for nominal accelerating potential ranging between Co-60 and 17 MV. The measurements were performed in a liquid water phantom at 5 cm depth for 10x10 cm 2 collimator setting and source-to-detector distance of 100 cm. The response (nC/Gy) was normalized to Co-60 beam after corrections for the dose rate and temperature dependences for each diode. The energy dependence, calculated by taking the percent difference between the maximum and minimum sensitivity normalized to Co-60 beam, varied by 39% for the n-type Isorad Red, 26% for the n-type Isorad Electron, 19% for the QED Red (p-type), 15% for the QED Electron (p-type), 11% for the QED Blue (p-type), and 6% for the EDP10 diode for nominal accelerating potential between Co-60 and 17 MV. It varied by 34% for the Isorad-3 Gold 1 and 2, 35% for the Veridose Green, 15% for the Veridose Yellow, 9% for the Veridose Electron, 21% for the n-type QED Gold, 24% for the n-type QED Red, 3% for the EDP2 3G , 2% for the PFD (photon field detector), 7% for the EDP10 3G , and 16% for the EDP20 3G for nominal accelerating potential between Co-60 and 15 MV. The magnitude of the energy dependence is verified by Monte Carlo simulation. We concluded that the energy dependence does not depend on whether the diode is n- or p-type but rather depends mainly on the material around the die such as the buildup and the geometry of the buildup material. As a result, the value of the energy dependence can vary for each individual diode depending on the actual geometry and should be used with caution

  17. Radiative characteristics of a thin solid fuel at discrete levels of pyrolysis: Angular, spectral, and thermal dependencies

    Science.gov (United States)

    Pettegrew, Richard Dale

    Numerical models of solid fuel combustion rely on accurate radiative property values to properly account for radiative heat transfer to and from the surface. The spectral properties can change significantly over the temperature range from ambient to burnout temperature. The variations of these properties are due to mass loss (as the sample pyrolyzes), chemical changes, and surface finish changes. In addition, band-integrated properties can vary due to the shift in the peak of the Planck curve as the temperature increases, which results in differing weightings of the spectral values. These effects were quantified for a thin cellulosic fuel commonly used in microgravity combustion studies (KimWipesRTM). Pyrolytic effects were simulated by heat-treating the samples in a constant temperature oven for varying times. Spectral data was acquired using a Fourier Transform Infrared (FTIR) spectrometer, along with an integrating sphere. Data was acquired at different incidence angles by mounting the samples at different angles inside the sphere. Comparisons of samples of similar area density created using different heat-treatment regimens showed that thermal history of the samples was irrelevant in virtually all spectral regions, with overall results correlating well with changes in area density. Spectral, angular, and thermal dependencies were determined for a representative data set, showing that the spectral absorptance decreases as the temperature increases, and decreases as the incidence angle varies from normal. Changes in absorptance are primarily offset by corresponding changes in transmittances, with reflectance values shown to be low over the tested spectral region of 2.50 mum to 24.93 mum. Band-integrated values were calculated as a function of temperature for the entire tested spectral region, as well as limited bands relevant for thermal imaging applications. This data was used to demonstrate the significant error that is likely if incorrect emittance values are

  18. Parametric output-only identification of time-varying structures using a kernel recursive extended least squares TARMA approach

    Science.gov (United States)

    Ma, Zhi-Sai; Liu, Li; Zhou, Si-Da; Yu, Lei; Naets, Frank; Heylen, Ward; Desmet, Wim

    2018-01-01

    The problem of parametric output-only identification of time-varying structures in a recursive manner is considered. A kernelized time-dependent autoregressive moving average (TARMA) model is proposed by expanding the time-varying model parameters onto the basis set of kernel functions in a reproducing kernel Hilbert space. An exponentially weighted kernel recursive extended least squares TARMA identification scheme is proposed, and a sliding-window technique is subsequently applied to fix the computational complexity for each consecutive update, allowing the method to operate online in time-varying environments. The proposed sliding-window exponentially weighted kernel recursive extended least squares TARMA method is employed for the identification of a laboratory time-varying structure consisting of a simply supported beam and a moving mass sliding on it. The proposed method is comparatively assessed against an existing recursive pseudo-linear regression TARMA method via Monte Carlo experiments and shown to be capable of accurately tracking the time-varying dynamics. Furthermore, the comparisons demonstrate the superior achievable accuracy, lower computational complexity and enhanced online identification capability of the proposed kernel recursive extended least squares TARMA approach.

  19. Study of excitation energy dependence of nuclear level density parameter

    International Nuclear Information System (INIS)

    Mohanto, G.; Nayak, B.K.; Saxena, A.

    2016-01-01

    In the present study, we have populated CN by fusion reaction and excitation energy of the intermediate nuclei is determined after first chance α-emission to investigate excitation energy dependence of the NLD parameter. Evaporated neutron spectra were measured following alpha evaporation for obtaining NLD parameter for the reaction 11 B + 197 Au, populating CN 208 Po. This CN after evaporating an α-particle populates intermediate nucleus 204 Pb. The 204 Pb has magic number of Z=82. Our aim is to study the excitation energy dependence of NLD parameter for closed shell nuclei

  20. The Effect of Cerebellar Transcranial Direct Current Stimulation on A Throwing Task Depends on Individual Level of Task Performance.

    Science.gov (United States)

    Mizuguchi, Nobuaki; Katayama, Takashi; Kanosue, Kazuyuki

    2018-02-10

    The effect of cerebellar transcranial direct current stimulation (tDCS) on motor performance remains controversial. Some studies suggest that the effect of tDCS depends upon task-difficulty and individual level of task performance. Here, we investigated whether the effect of cerebellar tDCS on the motor performance depends upon the individual's level of performance. Twenty-four naïve participants practiced dart throwing while receiving a 2-mA cerebellar tDCS for 20 min under three stimulus conditions (anodal-, cathodal-, and sham-tDCS) on separate days with a double-blind, counter-balanced cross-over design. Task performance was assessed by measuring the distance between the center of the bull's eye and the dart's position. Although task performance tended to improve throughout the practice under all stimulus conditions, improvement within a given day was not significant as compared to the first no-stimulus block. In addition, improvement did not differ among stimulation conditions. However, the magnitude of improvement was associated with an individual's level of task performance only under cathodal tDCS condition (p performance improvement only for the sub-group of participants with lower performance levels as compared to that with sham-tDCS (p task performance. Thus, cerebellar tDCS would facilitate learning of a complex motor skill task only in a subset of individuals. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  1. A Comparative Study of Finland and Chile: The Culture-Dependent Significance of the Individual and Interindividual Levels of the Mathematics-Related Affect

    Science.gov (United States)

    Tuohilampi, Laura; Laine, Anu; Hannula, Markku S.; Varas, Leonor

    2016-01-01

    Mathematics-related affect is established regarding both individual and interindividual levels. However, the interaction between the levels has not been elaborated. Furthermore, it is known that people may draw either from intrinsic or extrinsic experiences to construct their identities depending on their cultural environment. Thus, affective…

  2. Beam position dependence of a wall-current monitor

    International Nuclear Information System (INIS)

    Tamiya, K.; Asami, A.; Suwada, T.; Urano, T.; Kobayashi, H.

    1995-01-01

    It was pointed out recently that there exists an appreciable beam position dependence in the wall-current monitor widely used in electron accelerators. Detailed study of this dependence is performed on a test bench varying the pulse width and the frequency of the input signal simulating the beam. The results of experiments show that when the pulse width becomes shorter more appreciable becomes the dependence, and it approaches to that of calculated from the method of images. A unified analysis is under way. (author)

  3. Marijuana smoking: effects of varying puff volume and breathhold duration.

    Science.gov (United States)

    Azorlosa, J L; Greenwald, M K; Stitzer, M L

    1995-02-01

    Two studies were conducted to quantify biological and behavioral effects resulting from exposure to controlled doses of marijuana smoke. In one study, puff volume (30, 60 and 90 ml) and in a second study, breathhold duration (0, 10 and 20 sec) were systematically varied while holding constant other smoking topography parameters (number of puffs = 10, interpuff interval = 60 sec and inhalation volume = 25% of vital capacity). Each study also varied levels of delta 9-tetrahydro-cannabinol marijuana cigarette content (1.75% and 3.55%). Regular marijuana users served as subjects (n = 7 in each experiment). Subjects smoked 10 puffs in each of six sessions; a seventh, nonsmoking session (all measures recorded at the same times as in active smoking sessions) served as a control. Variations in puff volume produced significant dose-related changes in postsmoking plasma delta 9-tetrahydro-cannabinol levels, carbon monoxide boost and subjective effects (e.g., "high"). In contrast, breathholding for 10 or 20 sec versus 0 sec increased plasma delta 9-tetrahydro-cannabinol levels but not CO boost or subjective effects. Task performance measures were not reliably influenced by marijuana smoke exposure within the dosing ranges examined. These findings confirm the utility of the controlled smoking technology, support the notion that cumulative puff volume systematically influences biological exposure and subjective effects, but cast doubt on the common belief that prolonged breathholding of marijuana smoke enhances classical subjective effects associated with its reinforcing value in humans.

  4. Global Robust Stability of Switched Interval Neural Networks with Discrete and Distributed Time-Varying Delays of Neural Type

    Directory of Open Access Journals (Sweden)

    Huaiqin Wu

    2012-01-01

    Full Text Available By combing the theories of the switched systems and the interval neural networks, the mathematics model of the switched interval neural networks with discrete and distributed time-varying delays of neural type is presented. A set of the interval parameter uncertainty neural networks with discrete and distributed time-varying delays of neural type are used as the individual subsystem, and an arbitrary switching rule is assumed to coordinate the switching between these networks. By applying the augmented Lyapunov-Krasovskii functional approach and linear matrix inequality (LMI techniques, a delay-dependent criterion is achieved to ensure to such switched interval neural networks to be globally asymptotically robustly stable in terms of LMIs. The unknown gain matrix is determined by solving this delay-dependent LMIs. Finally, an illustrative example is given to demonstrate the validity of the theoretical results.

  5. Multiscale response of ionic systems to a spatially varying electric field

    Directory of Open Access Journals (Sweden)

    Jesper Schmidt Hansen

    2017-05-01

    Full Text Available In this paper the response of ionic systems subjected to a spatially varying electric field is studied. Following the Nernst-Planck equation, two forces driving the mass flux are present, namely, the concentration gradient and the electric potential gradient. The mass flux due to the concentration gradient is modelled through Fick's law, and a new constitutive relation for the mass flux due to the potential gradient is proposed. In the regime of low screening the response function due to the potential gradient is closely related to the ionic conductivity. In the large screening regime, on the other hand, the response function is governed by the charge-charge structure. Molecular dynamics simulations are conducted and the two wave vector dependent response functions are evaluated for models of a molten salt and an ionic liquid. In the low screening regime the response functions show same wave vector dependency, indicating that it is the same underlying physical processes that govern the response. In the screening regime the wave vector dependency is very different and, thus, the overall response is determined by different processes. This is in agreement with the observed failure of the Nernst-Einstein relation.

  6. Marginal ambulatory teaching cost under varying levels of service utilization.

    Science.gov (United States)

    Panton, D M; Mushlin, A I; Gavett, J W

    1980-06-01

    The ambulatory component of residency training jointly produces two products, namely, training and patient services. In costing educational programs of this type, two approaches are frequently taken. The first considers the total costs of the educational program, including training and patient services. These costs are usually constructed from historical accounting records. The second approach attempts to cost the joint products separately, based upon estimates of future changes in program costs, if the product in question is added to or removed from the program. The second approach relates to typical decisions facing the managers of medical centers and practices used for teaching purposes. This article reports such a study of costs in a primary-care residency training program in a hospital outpatient setting. The costs of the product, i.e., on-the-job training, are evaluated using a replacement-cost concept under different levels of patient services. The results show that the cost of the product, training, is small at full clinical utilization and is sensitive to changes in the volume of services provided.

  7. Conditional CAPM: Time-varying Betas in the Brazilian Market

    Directory of Open Access Journals (Sweden)

    Frances Fischberg Blank

    2014-10-01

    Full Text Available The conditional CAPM is characterized by time-varying market beta. Based on state-space models approach, beta behavior can be modeled as a stochastic process dependent on conditioning variables related to business cycle and estimated using Kalman filter. This paper studies alternative models for portfolios sorted by size and book-to-market ratio in the Brazilian stock market and compares their adjustment to data. Asset pricing tests based on time-series and cross-sectional approaches are also implemented. A random walk process combined with conditioning variables is the preferred model, reducing pricing errors compared to unconditional CAPM, but the errors are still significant. Cross-sectional test show that book-to-market ratio becomes less relevant, but past returns still capture cross-section variation

  8. The effect of spatially varying velocity field on the transport of radioactivity in a porous medium.

    Science.gov (United States)

    Sen, Soubhadra; Srinivas, C V; Baskaran, R; Venkatraman, B

    2016-10-01

    In the event of an accidental leak of the immobilized nuclear waste from an underground repository, it may come in contact of the flow of underground water and start migrating. Depending on the nature of the geological medium, the flow velocity of water may vary spatially. Here, we report a numerical study on the migration of radioactivity due to a space dependent flow field. For a detailed analysis, seven different types of velocity profiles are considered and the corresponding concentrations are compared. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Synchronization criterion for Lur'e type complex dynamical networks with time-varying delay

    International Nuclear Information System (INIS)

    Ji, D.H.; Park, Ju H.; Yoo, W.J.; Won, S.C.; Lee, S.M.

    2010-01-01

    In this Letter, the synchronization problem for a class of complex dynamical networks in which every identical node is a Lur'e system with time-varying delay is considered. A delay-dependent synchronization criterion is derived for the synchronization of complex dynamical network that represented by Lur'e system with sector restricted nonlinearities. The derived criterion is a sufficient condition for absolute stability of error dynamics between the each nodes and the isolated node. Using a convex representation of the nonlinearity for error dynamics, the stability condition based on the discretized Lyapunov-Krasovskii functional is obtained via LMI formulation. The proposed delay-dependent synchronization criterion is less conservative than the existing ones. The effectiveness of our work is verified through numerical examples.

  10. Is there dependence and systemic risk between oil and renewable energy stock prices?

    International Nuclear Information System (INIS)

    Reboredo, Juan C.

    2015-01-01

    We study systemic risk and dependence between oil and renewable energy markets using copulas to characterize the dependence structure and to compute the conditional value-at-risk as a measure of systemic risk. We found significant time-varying average and symmetric tail dependence between oil returns and several global and sectoral renewable energy indices. Our evidence on systemic risk indicates that oil price dynamics significantly contributes around 30% to downside and upside risk of renewable energy companies. These results have important implications for risk management and renewable energy policies. - Highlights: • We study systemic risk and dependence between oil and renewable energy markets. • Dependence and conditional value-at-risk is obtained through copulas. • Oil and renewable energy displayed time-varying average and symmetric tail dependence. • Oil price contribution to the downside and upside risks of renewable energy companies was around 30%

  11. Blood lead level in opium dependents and its association with anemia: A cross-sectional study from the capital of Iran

    Directory of Open Access Journals (Sweden)

    Behrooz Hashemi Domeneh

    2014-01-01

    Full Text Available Background: Opium dependence is one of the most challenging health problems in the developing countries as well as Iran. Among several health problems due to opium dependence, there are limited reports indicating the presence of lead in opium. The aim of this study is to investigate the blood lead level (BLL in oral and inhalational opium dependents and its association with anemia. Materials and Methods: A cross-sectional study was done among 86 opium dependent patients who were referred to five large detoxification centers in Tehran city and 48 healthy individuals. BLL was assessed using the atomic absorption spectrometry technique. Multivariate analysis of variance and binary logistic regression analysis were performed for statistical assessment using SPSS version 18 for Windows. Results: The highest BLL was detected in oral opium dependent group (mean = 11.75, standard deviation (SD = 6.06 in comparison to inhalational opium dependent group (mean = 7.07, SD = 3.61 and healthy control group (mean = 6.05, SD = 1.83. Anemia was detected in 38% of oral-opium dependent and 43% of inhalational-opium dependent group. Age (odds ratio (OR: 1.06, 95% confidence interval (CI: 1.03-1.09 and opium dependence (OR: 3.59, 95% CI: 1.69-7.59 were significant predictors of anemia in these patients (P < 0.001. Conclusion: The results of this study confirmed the higher BLL in opium dependents, especially with an oral form of consumption.

  12. Physiological relevance of plant 2-Cys peroxiredoxin overoxidation level and oligomerization status.

    Science.gov (United States)

    Cerveau, Delphine; Ouahrani, Djelloul; Marok, Mohamed Amine; Blanchard, Laurence; Rey, Pascal

    2016-01-01

    Peroxiredoxins are ubiquitous thioredoxin-dependent peroxidases presumed to display, upon environmental constraints, a chaperone function resulting from a redox-dependent conformational switch. In this work, using biochemical and genetic approaches, we aimed to unravel the factors regulating the redox status and the conformation of the plastidial 2-Cys peroxiredoxin (2-Cys PRX) in plants. In Arabidopsis, we show that in optimal growth conditions, the overoxidation level mainly depends on the availability of thioredoxin-related electron donors, but not on sulfiredoxin, the enzyme reducing the 2-Cys PRX overoxidized form. We also observed that upon various physiological temperature, osmotic and light stress conditions, the overoxidation level and oligomerization status of 2-Cys PRX can moderately vary depending on the constraint type. Further, no major change was noticed regarding protein conformation in water-stressed Arabidopsis, barley and potato plants, whereas species-dependent up- and down-variations in overoxidation were observed. In contrast, both 2-Cys PRX overoxidation and oligomerization were strongly induced during a severe oxidative stress generated by methyl viologen. From these data, revealing that the oligomerization status of plant 2-Cys PRX does not exhibit important variation and is not tightly linked to the protein redox status upon physiologically relevant environmental constraints, the possible in planta functions of 2-Cys PRX are discussed. © 2015 John Wiley & Sons Ltd.

  13. Particle-particle and hole-hole RPA correlations at finite temperature and the temperature dependence of the level density parameter

    International Nuclear Information System (INIS)

    Vinh Mau, N.

    1987-11-01

    The pp-hh RPA equations obtained by summing the infinite series of ladder, upwards and backwards going diagrams in the temperature two particle Green's functions are derived at finite temperature. The contribution to the thermodynamic grand potential due to pp-hh RPA correlations is calculated simultaneously to that of ph RPA correlations. A schematic model is constructed which shows that, as for ph RPA states, the energies of pp and hh RPA states have no temperature dependence at not too high temperature. Within the same model, the temperature dependence of the level density parameter is discussed

  14. Particle-particle and hole-hole RPA correlations at finite temperature and the temperature dependence of the level density parameter

    International Nuclear Information System (INIS)

    Vinh Mau, N.

    1989-01-01

    The pp-hh RPA equations obtained by summing the infinite series of ladder, upwards- and backwards-going diagrams in the temperature two-particle Green functions are derived at finite temperature. The contribution to the thermodynamic grand potential due to pp-hh RPA correlations is calculated simultaneously to that of ph RPA correlations. A schematic model is constructed which shows that, as for ph RPA states, the energies of pp and hh RPA states have no temperature dependence at not too high temperature. Within the same model, the temperature dependence of the level density parameter is discussed. (orig.)

  15. MEDICARE PAYMENTS AND SYSTEM-LEVEL HEALTH-CARE USE

    Science.gov (United States)

    ROBBINS, JACOB A.

    2015-01-01

    The rapid growth of Medicare managed care over the past decade has the potential to increase the efficiency of health-care delivery. Improvements in care management for some may improve efficiency system-wide, with implications for optimal payment policy in public insurance programs. These system-level effects may depend on local health-care market structure and vary based on patient characteristics. We use exogenous variation in the Medicare payment schedule to isolate the effects of market-level managed care enrollment on the quantity and quality of care delivered. We find that in areas with greater enrollment of Medicare beneficiaries in managed care, the non–managed care beneficiaries have fewer days in the hospital but more outpatient visits, consistent with a substitution of less expensive outpatient care for more expensive inpatient care, particularly at high levels of managed care. We find no evidence that care is of lower quality. Optimal payment policies for Medicare managed care enrollees that account for system-level spillovers may thus be higher than those that do not. PMID:27042687

  16. Calculation of rectal dose surface histograms in the presence of time varying deformations

    International Nuclear Information System (INIS)

    Roeske, John C.; Spelbring, Danny R.; Vijayakumar, S.; Forman, Jeffrey D.; Chen, George T.Y.

    1996-01-01

    Purpose: Dose volume (DVH) and dose surface histograms (DSH) of the bladder and rectum are usually calculated from a single treatment planning scan. These DVHs and DSHs will eventually be correlated with complications to determine parameters for normal tissue complication probabilities (NTCP). However, from day to day, the size and shape of the rectum and bladder may vary. The purpose of this study is to compare a more accurate estimate of the time integrated DVHs and DSHs of the rectum (in the presence of daily variations in rectal shape) to initial DVHs/DSHs. Methods: 10 patients were scanned once per week during the course of fractionated radiotherapy, typically accumulating a total of six scans. The rectum and bladder were contoured on each of the studies. The model used to assess effects of rectal contour deformation is as follows: the contour on a given axial slice (see figure) is boxed within a rectangle. A line drawn parallel to the AP axis through the rectangle equally partitions the box. Starting at the intersection of the vertical line and the rectal contour, points on the contour are marked off representing the same rectal dose point, even in the presence of distortion. Corresponding numbered points are used to sample the dose matrix and create a composite DSH. The model assumes uniform stretching of the rectal contour for any given axial cut, and no twist of the structure or vertical displacement. A similar model is developed for the bladder with spherical symmetry. Results: Normalized DSHs (nDSH) for each CT scan were calculated as well as the time averaged nDSH over all scans. These were compared with the nDSH from the initial planning scan. Individual nDSHs differed by 8% surface area irradiated at the 80% dose level, to as much as 20% surface area in the 70-100% dose range. DSH variations are due to position and shape changes in the rectum during different CT scans. The spatial distribution of dose is highly variable, and depends on the field

  17. One-dimensional radionuclide transport under time-varying conditions

    International Nuclear Information System (INIS)

    Gelbard, F.; Olague, N.E.; Longsine, D.E.

    1990-01-01

    This paper discusses new analytical and numerical solutions presented for one-dimensional radionuclide transport under time-varying fluid-flow conditions including radioactive decay. The analytical solution assumes that all radionuclides have identical retardation factors, and is limited to instantaneous releases. The numerical solution does not have these limitations, but is tested against the limiting case given for the analytical solution. Reasonable agreement between the two solutions was found. Examples are given for the transport of a three-member radionuclide chain transported over distances and flow rates comparable to those reported for Yucca Mountain, the proposed disposal site for high-level nuclear waste

  18. t{f, tjse of dpw at varying levels tn cattle fattening rations

    African Journals Online (AJOL)

    As gevolgvan die laer rantsoenkoste was die insluiting van DHM. in plaas van sonneblomoliekoekmecl, selfs tct by die l2/, perl van inskakeling teen heersendepryseekodmies geregverdig". SUMMARY. ..... performance, the saving in ration costs is such that even at the l2/' level of inclusion, the use of DPW at R40/ ton is still ...

  19. Adaptive control of chaotic systems with stochastic time varying unknown parameters

    Energy Technology Data Exchange (ETDEWEB)

    Salarieh, Hassan [Center of Excellence in Design, Robotics and Automation, Department of Mechanical Engineering, Sharif University of Technology, P.O. Box 11365-9567, Azadi Avenue, Tehran (Iran, Islamic Republic of)], E-mail: salarieh@mech.sharif.edu; Alasty, Aria [Center of Excellence in Design, Robotics and Automation, Department of Mechanical Engineering, Sharif University of Technology, P.O. Box 11365-9567, Azadi Avenue, Tehran (Iran, Islamic Republic of)], E-mail: aalasti@sharif.edu

    2008-10-15

    In this paper based on the Lyapunov stability theorem, an adaptive control scheme is proposed for stabilizing the unstable periodic orbits (UPO) of chaotic systems. It is assumed that the chaotic system has some linearly dependent unknown parameters which are stochastically time varying. The stochastic parameters are modeled through the Weiner process derivative. To demonstrate the effectiveness of the proposed technique it has been applied to the Lorenz, Chen and Rossler dynamical systems, as some case studies. Simulation results indicate that the proposed adaptive controller has a high performance in stabilizing the UPO of chaotic systems in noisy environment.

  20. Monitoring of 7Be in surface air of varying PM10 concentrations

    International Nuclear Information System (INIS)

    Chao, J.H.; Liu, C.C.; Cho, I.C.; Niu, H.

    2014-01-01

    In this study, beryllium-7 ( 7 Be) concentrations of surface air were monitored throughout a span of 23 years (1992–2012) in the Taiwanese cities Yilan, Taipei, Taichung, and Kaohsiung. During this period, particulate matter (PM) concentrations, in terms of PM 10 , were collected monthly from the nearest air-quality pollutant monitoring stations and compared against 7 Be concentrations. Seasonal monsoons influenced 7 Be concentrations in all cities, resulting in high winter and low summer concentrations. In addition, the meteorological conditions caused seasonal PM 10 variations, yielding distinct patterns among the cities. There was no correlation between 7 Be and PM 10 in the case cities. The average annual 7 Be concentrations varied little among the cities, ranging from 2.9 to 3.5 mBq/m 3 , while the PM 10 concentrations varied significantly from 38 μg/m 3 in Yilan to 92 μg/m 3 in Kaohsiung depending on the degree of air pollution and meteorological conditions. The correlation between the 7 Be concentration and gross-beta activities (A β ) in air implied that the 7 Be was mainly attached to crustal PM and its concentration varied little among the cities, regardless of the increase in anthropogenic PM in air-polluted areas. - Highlights: • Both 7 Be and PM 10 concentrations were monitored in four Taiwanese cities from 1992 to 2012. • Seasonal variations of 7 Be and PM 10 were explained based on on meteorological and pollution conditions. • The annual concentrations of 7 Be varied little among the four cities even in high PM environment. • 7 Be is believed to mainly attach to natural PM in the cities that exhibited varying PM 10 concentrations

  1. Performance exploration of an energy harvester near the varying magnetic field of an operating induction motor

    International Nuclear Information System (INIS)

    Uzun, Yunus; Kurt, Erol

    2013-01-01

    Highlights: • This paper explores the piezoelectric harvester performance. • The varying magnetic field generates electricity via exciting harvester. • Generated power should be optimized via load resistance. • 0.11 mW/cm 3 Power can be generated from 500 cm 3 surrounding volume. - Abstract: This paper reports a performance exploration of a piezoelectric harvester which is positioned near an operating induction motor. The harvester includes a magnet knob in a pendulum arrangement, which ascertains mechanical vibrations under the varying magnetic field. This energy harvester transforms the ambient unused magnetic energy into the electricity due to the piezoelectric layer attached to the pendulum. It has been proven that when the motor is under operation, the varying ambient field causes a varying magnetic force at the tip of harvester, then output voltage between the terminals of piezoelectric layer is produced due to the mechanical vibrations. This output signal has some characteristics of the operating induction motor in terms of its operation frequency, number of magnetic pole and natural frequency of the harvester. Since the surrounding field of the induction motor directly depends on the current flowing through the windings and electrical parameters, both the amplitude U and the frequency ω m of the harvested voltage can be characterized after some certain parametrical explorations. It has been proven that the harvested voltage strictly depends on the electrical load, which is attached to the terminals of the harvester, after the rectifying circuit. The harvested power per surrounding volume can be increased up to 0.11 mW/cm 3 , if the entire surrounding volume of the motor is considered

  2. Zhang neural network for online solution of time-varying convex quadratic program subject to time-varying linear-equality constraints

    International Nuclear Information System (INIS)

    Zhang Yunong; Li Zhan

    2009-01-01

    In this Letter, by following Zhang et al.'s method, a recurrent neural network (termed as Zhang neural network, ZNN) is developed and analyzed for solving online the time-varying convex quadratic-programming problem subject to time-varying linear-equality constraints. Different from conventional gradient-based neural networks (GNN), such a ZNN model makes full use of the time-derivative information of time-varying coefficient. The resultant ZNN model is theoretically proved to have global exponential convergence to the time-varying theoretical optimal solution of the investigated time-varying convex quadratic program. Computer-simulation results further substantiate the effectiveness, efficiency and novelty of such ZNN model and method.

  3. Predicting long-term temperature increase for time-dependent SAR levels with a single short-term temperature response.

    Science.gov (United States)

    Carluccio, Giuseppe; Bruno, Mary; Collins, Christopher M

    2016-05-01

    Present a novel method for rapid prediction of temperature in vivo for a series of pulse sequences with differing levels and distributions of specific energy absorption rate (SAR). After the temperature response to a brief period of heating is characterized, a rapid estimate of temperature during a series of periods at different heating levels is made using a linear heat equation and impulse-response (IR) concepts. Here the initial characterization and long-term prediction for a complete spine exam are made with the Pennes' bioheat equation where, at first, core body temperature is allowed to increase and local perfusion is not. Then corrections through time allowing variation in local perfusion are introduced. The fast IR-based method predicted maximum temperature increase within 1% of that with a full finite difference simulation, but required less than 3.5% of the computation time. Even higher accelerations are possible depending on the time step size chosen, with loss in temporal resolution. Correction for temperature-dependent perfusion requires negligible additional time and can be adjusted to be more or less conservative than the corresponding finite difference simulation. With appropriate methods, it is possible to rapidly predict temperature increase throughout the body for actual MR examinations. © 2015 Wiley Periodicals, Inc.

  4. Angular dependent XPS study of surface band bending on Ga-polar n-GaN

    Science.gov (United States)

    Huang, Rong; Liu, Tong; Zhao, Yanfei; Zhu, Yafeng; Huang, Zengli; Li, Fangsen; Liu, Jianping; Zhang, Liqun; Zhang, Shuming; Dingsun, An; Yang, Hui

    2018-05-01

    Surface band bending and composition of Ga-polar n-GaN with different surface treatments were characterized by using angular dependent X-ray photoelectron spectroscopy. Upward surface band bending of varying degree was observed distinctly upon to the treatment methods. Besides the nitrogen vacancies, we found that surface states of oxygen-containing absorbates (O-H component) also contribute to the surface band bending, which lead the Fermi level pined at a level further closer to the conduction band edge on n-GaN surface. The n-GaN surface with lower surface band bending exhibits better linear electrical properties for Ti/GaN Ohmic contacts. Moreover, the density of positively charged surface states could be derived from the values of surface band bending.

  5. Three-Level Supply Chain Coordination under Disruptions Based on Revenue-Sharing Contract with Price Dependent Demand

    Directory of Open Access Journals (Sweden)

    Qinghua Pang

    2014-01-01

    Full Text Available Considering the market demand is stochastic and dependent on price, this paper shows that the revenue-sharing contract could coordinate a three-level supply chain consisting of one manufacturer, one distributor, and one retailer under normal environment. However, the original revenue-sharing contract cannot coordinate the supply chain under disruptions in circumstances of certain incidents leading to significant changes in market demand and causing additional deviation costs. To solve the problem, this essay introduces two improved forms of revenue-sharing contract: a mixed contract form based on a quantity discount policy and a pure form, which are characterized by antidisruption ability. The model of improved revenue-sharing contract is optimized when the market demand is in the additive form or in the multiplicative form with price dependent demand. Formulas are given to calculate the optimal contract parameters. Finally, this essay demonstrates the accuracy of the model of improved revenue-sharing contract with the help of numerical examples.

  6. Impulsive effect on global exponential stability of BAM fuzzy cellular neural networks with time-varying delays

    Science.gov (United States)

    Li, Kelin

    2010-02-01

    In this article, a class of impulsive bidirectional associative memory (BAM) fuzzy cellular neural networks (FCNNs) with time-varying delays is formulated and investigated. By employing delay differential inequality and M-matrix theory, some sufficient conditions ensuring the existence, uniqueness and global exponential stability of equilibrium point for impulsive BAM FCNNs with time-varying delays are obtained. In particular, a precise estimate of the exponential convergence rate is also provided, which depends on system parameters and impulsive perturbation intention. It is believed that these results are significant and useful for the design and applications of BAM FCNNs. An example is given to show the effectiveness of the results obtained here.

  7. Will male advertisement be a reliable indicator of paternal care, if offspring survival depends on male care?

    OpenAIRE

    Kelly, Natasha B.; Alonzo, Suzanne H.

    2009-01-01

    Existing theory predicts that male signalling can be an unreliable indicator of paternal care, but assumes that males with high levels of mating success can have high current reproductive success, without providing any parental care. As a result, this theory does not hold for the many species where offspring survival depends on male parental care. We modelled male allocation of resources between advertisement and care for species with male care where males vary in quality, and the effect of c...

  8. Spacetime-varying couplings and Lorentz violation

    International Nuclear Information System (INIS)

    Kostelecky, V. Alan; Lehnert, Ralf; Perry, Malcolm J.

    2003-01-01

    Spacetime-varying coupling constants can be associated with violations of local Lorentz invariance and CPT symmetry. An analytical supergravity cosmology with a time-varying fine-structure constant provides an explicit example. Estimates are made for some experimental constraints

  9. Output-Only Modal Parameter Recursive Estimation of Time-Varying Structures via a Kernel Ridge Regression FS-TARMA Approach

    Directory of Open Access Journals (Sweden)

    Zhi-Sai Ma

    2017-01-01

    Full Text Available Modal parameter estimation plays an important role in vibration-based damage detection and is worth more attention and investigation, as changes in modal parameters are usually being used as damage indicators. This paper focuses on the problem of output-only modal parameter recursive estimation of time-varying structures based upon parameterized representations of the time-dependent autoregressive moving average (TARMA. A kernel ridge regression functional series TARMA (FS-TARMA recursive identification scheme is proposed and subsequently employed for the modal parameter estimation of a numerical three-degree-of-freedom time-varying structural system and a laboratory time-varying structure consisting of a simply supported beam and a moving mass sliding on it. The proposed method is comparatively assessed against an existing recursive pseudolinear regression FS-TARMA approach via Monte Carlo experiments and shown to be capable of accurately tracking the time-varying dynamics in a recursive manner.

  10. Seasonal dependence of the predictable low-level circulation patterns over the tropical Indo-Pacific domain

    Science.gov (United States)

    Zhang, Tuantuan; Huang, Bohua; Yang, Song; Laohalertchai, Charoon

    2018-06-01

    The seasonal dependence of the prediction skill of 850-hPa monthly zonal wind over the tropical Indo-Pacific domain is examined using the ensemble reforecasts for 1983-2010 from the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis and Reforecast (CFSRR) project. According to a maximum signal-to-noise empirical orthogonal function analysis, the most predictable patterns of atmospheric low-level circulation are associated with the developing and maturing phases of El Niño-Southern Oscillation (ENSO). The CFSv2 is capable of predicting these ENSO-related patterns up to 9-months in advance for all months, except for May-June when the effect of the spring barrier is strong. The other predictable climate processes associated with the low-level atmospheric circulation are more seasonally dependent. For winter and spring, the second most predictable patterns are associated with the ENSO decaying phase. Within these seasons, the monthly evolution of the predictable patterns is characterized by a southward shift of westerly wind anomalies, generated by the interaction between the annual cycle and the ENSO signals (i.e., the combination-mode). In general, the CFSv2 hindcast well predicts these patterns at least 5 months in advance for spring, while shows much lower skills for winter months. In summer, the second predictable patterns are associated with the western North Pacific (WNP) monsoon (i.e., the WNP anticyclone/cyclone) in short leads while associated with ENSO in longer leads (after 4-month lead). The second predictable patterns in fall are mainly associated with tropical Indian Ocean Dipole, which can be predicted 3 months in advance.

  11. Dietary adaptation of FADS genes in Europe varied across time and geography.

    Science.gov (United States)

    Ye, Kaixiong; Gao, Feng; Wang, David; Bar-Yosef, Ofer; Keinan, Alon

    2017-05-26

    Fatty acid desaturase (FADS) genes encode rate-limiting enzymes for the biosynthesis of omega-6 and omega-3 long-chain polyunsaturated fatty acids (LCPUFAs). This biosynthesis is essential for individuals subsisting on LCPUFA-poor diets (for example, plant-based). Positive selection on FADS genes has been reported in multiple populations, but its cause and pattern in Europeans remain unknown. Here we demonstrate, using ancient and modern DNA, that positive selection acted on the same FADS variants both before and after the advent of farming in Europe, but on opposite (that is, alternative) alleles. Recent selection in farmers also varied geographically, with the strongest signal in southern Europe. These varying selection patterns concur with anthropological evidence of varying diets, and with the association of farming-adaptive alleles with higher FADS1 expression and thus enhanced LCPUFA biosynthesis. Genome-wide association studies reveal that farming-adaptive alleles not only increase LCPUFAs, but also affect other lipid levels and protect against several inflammatory diseases.

  12. Exponential stability for stochastic delayed recurrent neural networks with mixed time-varying delays and impulses: the continuous-time case

    International Nuclear Information System (INIS)

    Karthik Raja, U; Leelamani, A; Raja, R; Samidurai, R

    2013-01-01

    In this paper, the exponential stability for a class of stochastic neural networks with time-varying delays and impulsive effects is considered. By constructing suitable Lyapunov functionals and by using the linear matrix inequality optimization approach, we obtain sufficient delay-dependent criteria to ensure the exponential stability of stochastic neural networks with time-varying delays and impulses. Two numerical examples with simulation results are provided to illustrate the effectiveness of the obtained results over those already existing in the literature. (paper)

  13. A Test of the Active-Day Fraction Method of Sunspot Group Number Calibration: Dependence on the Level of Solar Activity

    Science.gov (United States)

    Willamo, T.; Usoskin, I. G.; Kovaltsov, G. A.

    2018-04-01

    The method of active-day fraction (ADF) was proposed recently to calibrate different solar observers to standard observational conditions. The result of the calibration may depend on the overall level of solar activity during the observational period. This dependency is studied quantitatively using data of the Royal Greenwich Observatory by formally calibrating synthetic pseudo-observers to the full reference dataset. It is shown that the sunspot group number is precisely estimated by the ADF method for periods of moderate activity, may be slightly underestimated by 0.5 - 1.5 groups ({≤} 10%) for strong and very strong activity, and is strongly overestimated by up to 2.5 groups ({≤} 30%) for weak-to-moderate activity. The ADF method becomes inapplicable for the periods of grand minima of activity. In general, the ADF method tends to overestimate the overall level of activity and to reduce the long-term trends.

  14. Biases in attention, interpretation, memory, and associations in children with varying levels of spider fear: Inter-relations and prediction of behavior.

    Science.gov (United States)

    Klein, Anke M; van Niekerk, Rianne; Ten Brink, Giovanni; Rapee, Ronald M; Hudson, Jennifer L; Bögels, Susan M; Becker, Eni S; Rinck, Mike

    2017-03-01

    Cognitive theories suggest that cognitive biases may be related and together influence the anxiety response. However, little is known about the interrelations of cognitive bias tasks and whether they allow for an improved prediction of fear-related behavior in addition to self-reports. This study simultaneously addressed several types of cognitive biases in children, to investigate attention bias, interpretation bias, memory bias and fear-related associations, their interrelations and the prediction of behavior. Eighty-one children varying in their levels of spider fear completed the Spider Anxiety and Disgust Screening for Children and performed two Emotional Stroop tasks, a Free Recall task, an interpretation task including size and distance indication, an Affective Priming Task, and a Behavioral Assessment Test. We found an attention bias, interpretation bias, and fear-related associations, but no evidence for a memory bias. The biases showed little overlap. Attention bias, interpretation bias, and fear-related associations predicted unique variance in avoidance of spiders. Interpretation bias and fear-related associations remained significant predictors, even when self-reported fear was included as a predictor. Children were not seeking help for their spider fear and were not tested on clinical levels of spider phobia. This is the first study to find evidence that different cognitive biases each predict unique variance in avoidance behavior. Furthermore, it is also the first study in which we found evidence for a relation between fear of spiders and size and distance indication. We showed that this bias is distinct from other cognitive biases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. The dependence of stellar properties on initial cloud density

    Science.gov (United States)

    Jones, Michael O.; Bate, Matthew R.

    2018-05-01

    We investigate the dependence of stellar properties on the initial mean density of the molecular cloud in which stellar clusters form using radiation hydrodynamical simulations that resolve the opacity limit for fragmentation. We have simulated the formation of three star clusters from the gravitational collapse of molecular clouds whose densities vary by a factor of a hundred. As with previous calculations including radiative feedback, we find that the dependence of the characteristic stellar mass, Mc, on the initial mean density of the cloud, ρ, is weaker than the dependence of the thermal Jeans mass. However, unlike previous calculations, which found no statistically significant variation in the median mass with density, we find a weak dependence approximately of the form Mc∝ρ-1/5. The distributions of properties of multiple systems do not vary significantly between the calculations. We compare our results to the result of observational surveys of star-forming regions, and suggest that the similarities between the properties of our lowest density calculation and the nearby Taurus-Auriga region indicate that the apparent excess of solar-type stars observed may be due to the region's low density.

  16. Tracking control of time-varying knee exoskeleton disturbed by interaction torque.

    Science.gov (United States)

    Li, Zhan; Ma, Wenhao; Yin, Ziguang; Guo, Hongliang

    2017-11-01

    Knee exoskeletons have been increasingly applied as assistive devices to help lower-extremity impaired people to make their knee joints move through providing external movement compensation. Tracking control of knee exoskeletons guided by human intentions often encounters time-varying (time-dependent) issues and the disturbance interaction torque, which may dramatically put an influence up on their dynamic behaviors. Inertial and viscous parameters of knee exoskeletons can be estimated to be time-varying due to unexpected mechanical vibrations and contact interactions. Moreover, the interaction torque produced from knee joint of wearers has an evident disturbance effect on regular motions of knee exoskeleton. All of these points can increase difficultly of accurate control of knee exoskeletons to follow desired joint angle trajectories. This paper proposes a novel control strategy for controlling knee exoskeleton with time-varying inertial and viscous coefficients disturbed by interaction torque. Such designed controller is able to make the tracking error of joint angle of knee exoskeletons exponentially converge to zero. Meanwhile, the proposed approach is robust to guarantee the tracking error bounded when the interaction torque exists. Illustrative simulation and experiment results are presented to show efficiency of the proposed controller. Additionally, comparisons with gradient dynamic (GD) approach and other methods are also presented to demonstrate efficiency and superiority of the proposed control strategy for tracking joint angle of knee exoskeleton. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  17. Level density parameter dependence of the fission cross sections of some subactinide nuclei induced by protons with the incident energy up to 250 MeV

    International Nuclear Information System (INIS)

    Aydin, A.; Yalim, H.A.; Tel, E.; Sarer, B.; Unal, R.; Sarpuen, I.H.; Kaplan, A.; Dag, M.

    2009-01-01

    This study aims to show the dependence on the choice of the ratio of the level density parameters a f and a n corresponding to the saddle point of fission and equilibrium deformation of nucleus, respectively, of the proton induced fission cross sections of some subactinide targets. The method was employed using different level density parameter ratios for each fission cross section calculation in ALICE/ASH computer code. The ALICE/ASH code calculations were compared both with the available experimental data and with the Prokofiev systematics data. It is found that the fission cross sections dependent heavily on the choice of level density parameter ratio in the fission and neutron emission channels, a f /a n , for some subactinide nuclei. To get a good description of the measured fission cross sections for subactinide nuclei, we used a ratio of the level density parameters in the fission and neutron emission channels, a f /a n , depending both on the target-nucleus and on the energy of the projectile, in agreement with results published in literature.

  18. 17β-estradiol increases liver and serum docosahexaenoic acid in mice fed varying levels of α-linolenic acid.

    Science.gov (United States)

    Mason, Julie K; Kharotia, Shikhil; Wiggins, Ashleigh K A; Kitson, Alex P; Chen, Jianmin; Bazinet, Richard P; Thompson, Lilian U

    2014-08-01

    Docosahexaenoic acid (DHA) is considered to be important for cardiac and brain function, and 17β-estradiol (E2) appears to increase the conversion of α-linolenic acid (ALA) into DHA. However, the effect of varying ALA intake on the positive effect of E2 on DHA synthesis is not known. Therefore, the objective of this study was to investigate the effects of E2 supplementation on tissue and serum fatty acids in mice fed a low-ALA corn oil-based diet (CO, providing 0.6 % fatty acids as ALA) or a high ALA flaxseed meal-based diet (FS, providing 11.2 % ALA). Ovariectomized mice were implanted with a slow-release E2 pellet at 3 weeks of age and half the mice had the pellet removed at 7 weeks of age. Mice were then randomized onto either the CO or FS diet. After 4 weeks, the DHA concentration was measured in serum, liver and brain. A significant main effect of E2 was found for liver and serum DHA, corresponding to 25 and 15 % higher DHA in livers of CO and FS rats, respectively, and 19 and 13 % in serum of CO and FS rats, respectively, compared to unsupplemented mice. There was no effect of E2 on brain DHA. E2 results in higher DHA in serum and liver, at both levels of dietary ALA investigated presently, suggesting that higher ALA intake may result in higher DHA in individuals with higher E2 status.

  19. Probing background ionization: positive streamers with varying pulse repetition rate and with a radioactive admixture

    International Nuclear Information System (INIS)

    Nijdam, S; Van Veldhuizen, E M; Ebert, U; Wormeester, G

    2011-01-01

    Positive streamers need a source of free electrons ahead of them to propagate. A streamer can supply these electrons by itself through photo-ionization, or the electrons can be present due to external background ionization. Here we investigate the effects of background ionization on streamer propagation and morphology by changing the gas composition and the repetition rate of the voltage pulses, and by adding a small amount of radioactive 85 Kr. We find that the general morphology of a positive streamer discharge in high-purity nitrogen depends on background ionization: at lower background ionization levels the streamers branch more and have a more feather-like appearance. This is observed both when varying the repetition rate and when adding 85 Kr, though side branches are longer with the radioactive admixture. But velocities and minimal diameters of streamers are virtually independent of the background ionization level. In air, the inception cloud breaks up into streamers at a smaller radius when the repetition rate and therefore the background ionization level is higher. When measuring the effects of the pulse repetition rate and of the radioactive admixture on the discharge morphology, we found that our estimates of background ionization levels are consistent with these observations; this gives confidence in the estimates. Streamer channels generally do not follow the paths of previous discharge channels for repetition rates of up to 10 Hz. We estimate the effect of recombination and diffusion of ions and free electrons from the previous discharge and conclude that the old trail has largely disappeared at the moment of the next voltage pulse; therefore the next streamers indeed cannot follow the old trail.

  20. Association of serum bicarbonate levels with mortality in patients with non-dialysis-dependent CKD

    Science.gov (United States)

    Kovesdy, Csaba P.; Anderson, John E.; Kalantar-Zadeh, Kamyar

    2009-01-01

    Background. Metabolic acidosis, usually manifested by low serum bicarbonate level, is common in chronic kidney disease (CKD) and appears to be associated with higher mortality in dialysis patients. It is not known whether a similar association is present in patients with non-dialysis-dependent CKD (NDD-CKD). Methods. We used multivariable-adjusted Cox models to examine the association between baseline and time-variable serum bicarbonate (measured as total CO2) with the outcomes of all-cause mortality and the composite of pre-dialysis mortality or end-stage renal disease in 1240 male patients with moderate and advanced NDD-CKD. Results. Serum bicarbonate showed a significant U-shaped association with all-cause mortality, with the highest mortality rate observed in patients with baseline serum bicarbonate levels <22 mmol/L [multivariable-adjusted hazard ratio (95% confidence interval) for patients with serum bicarbonate <22 mmol/L versus ≥22 mmol/L: 1.33 (1.05–1.69), P = 0.02] and the lowest mortality observed in patients with baseline serum bicarbonate of 26–29 mmol/L. The associations between lower serum bicarbonate level and mortality were more accentuated in subgroups of patients with better nutritional status and lower inflammation. Conclusions. Both lower and higher serum bicarbonates are associated with increased all-cause mortality in patients with moderate and advanced NDD-CKD. Clinical trials are needed to determine if therapeutic interventions aimed at optimizing serum bicarbonate can result in improved outcomes in this population. PMID:19015169

  1. Unemployment Insurance Benefit Levels and Consumption Changes

    DEFF Research Database (Denmark)

    Browning, Martin; Crossley, Thomas

    We use a survey of unemployed people to examine how a job loss impacts on household expenditures. The principal focus is on the effect of the level of income replacement provided by Unemployment Insurance. We restrict attention to a sub-sample of respondents who are still in their first spell...... of unemployment after six months. For this group we find large consumption falls, averaging about 16% of total expenditure. The actual fall depends on a variety of factors of which the most important is the pre-job loss ratio of the respondent's income to household income. The effects of varying the replacement...... within the household and hence on other facets of behaviour such as job search, unemployment duration and the quality of any new job taken...

  2. Diurnally varying annoyance due to railway and road traffic noise; Laermbelaestigung durch Strassen- und Schienenverkehr zu unterschiedlichen Tageszeiten

    Energy Technology Data Exchange (ETDEWEB)

    Schreckenberg, D. [Zentrum fuer Angewandte Psychologie, Umwelt- und Sozialforschung (ZEUS GmbH), Bochum (Germany); Guski, R. [Ruhr-Univ. Bochum, Fakultaet fuer Psychologie, Bochum (Germany)

    2005-07-01

    One of the most prominent non-auditory effects of noise influencing the life quality of human beings is the disturbance of activities (i.e. communicating, relaxing, working, sleeping). The disturbance of activities results in noise annoyance, and in the long run may lead to further health effects. Due to the fact that activities vary diurnally it is plausible to assume that peoples'' responses to noise differ depending on the times of day. The aim of the study, which is part of the German research network ''Quiet Traffic'' is to provide empirical data of dose-response relationships for different times of day (excluding the night). 1110 residents from four areas with dominant road traffic noise (683 subjects) and from two areas with dominant railway noise (427 subjects) have been asked in a face-to-face interview for contentment with house and living environment and noise reactions. 131 persons of the total sample took part in an additional study (experience-sampling study) in which the hourly noise annoyance was measured for three consecutive days using a handheld computer. For each subject individual source-specific immission noise level for each hour of the day has been calculated. There is higher annoyance due to road traffic noise in the late afternoon/evening from 4 pm to 7 pm. For railway noise higher annoyance is reported in the evening from 6 pm to 10 am. The reported differences in noise annoyance depending on the times of day are higher with increasing noise level. (orig.)

  3. Age-varying associations between nonmarital sexual behavior and depressive symptoms across adolescence and young adulthood.

    Science.gov (United States)

    Vasilenko, Sara A

    2017-02-01

    Research has demonstrated associations between adolescent sexual behavior and depressive symptoms, but no single study has examined individuals at different ages throughout adolescence and young adulthood in order to determine at what ages sexual behavior may be associated with higher or lower levels of depressive symptoms. Using nationally representative longitudinal data and an innovative method, the time-varying effect model (TVEM), which examines how the strength of an association changes over time, this study examines how nonmarital sexual intercourse is associated with depressive symptoms at different ages, which behaviors and contexts may contribute to these associations, and whether associations differ for male and female participants. Findings indicate that sexual behavior in adolescence is associated with a higher level of depressive symptoms, particularly for female adolescents, and this association is relatively consistent across different partner types and adolescent contexts. Associations between sexual behavior and depressive symptoms in young adulthood are more dependent on partner factors and adolescent contexts; sexual behavior in young adulthood is associated with fewer depressive symptoms for women who have sex with a single partner and for men whose parents did not strongly disapprove of adolescent sexual behavior. Findings suggest that delaying sexual behavior into young adulthood may have some benefits for mental health, although contextual and relationship factors also play a role. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  4. In the face of threat: neural and endocrine correlates of impaired facial emotion recognition in cocaine dependence.

    Science.gov (United States)

    Ersche, K D; Hagan, C C; Smith, D G; Jones, P S; Calder, A J; Williams, G B

    2015-05-26

    The ability to recognize facial expressions of emotion in others is a cornerstone of human interaction. Selective impairments in the recognition of facial expressions of fear have frequently been reported in chronic cocaine users, but the nature of these impairments remains poorly understood. We used the multivariate method of partial least squares and structural magnetic resonance imaging to identify gray matter brain networks that underlie facial affect processing in both cocaine-dependent (n = 29) and healthy male volunteers (n = 29). We hypothesized that disruptions in neuroendocrine function in cocaine-dependent individuals would explain their impairments in fear recognition by modulating the relationship with the underlying gray matter networks. We found that cocaine-dependent individuals not only exhibited significant impairments in the recognition of fear, but also for facial expressions of anger. Although recognition accuracy of threatening expressions co-varied in all participants with distinctive gray matter networks implicated in fear and anger processing, in cocaine users it was less well predicted by these networks than in controls. The weaker brain-behavior relationships for threat processing were also mediated by distinctly different factors. Fear recognition impairments were influenced by variations in intelligence levels, whereas anger recognition impairments were associated with comorbid opiate dependence and related reduction in testosterone levels. We also observed an inverse relationship between testosterone levels and the duration of crack and opiate use. Our data provide novel insight into the neurobiological basis of abnormal threat processing in cocaine dependence, which may shed light on new opportunities facilitating the psychosocial integration of these patients.

  5. Effects of long-term voluntary exercise on learning and memory processes: dependency of the task and level of exercise.

    Science.gov (United States)

    García-Capdevila, Sílvia; Portell-Cortés, Isabel; Torras-Garcia, Meritxell; Coll-Andreu, Margalida; Costa-Miserachs, David

    2009-09-14

    The effect of long-term voluntary exercise (running wheel) on anxiety-like behaviour (plus maze and open field) and learning and memory processes (object recognition and two-way active avoidance) was examined on Wistar rats. Because major individual differences in running wheel behaviour were observed, the data were analysed considering the exercising animals both as a whole and grouped according to the time spent in the running wheel (low, high, and very-high running). Although some variables related to anxiety-like behaviour seem to reflect an anxiogenic compatible effect, the view of the complete set of variables could be interpreted as an enhancement of defensive and risk assessment behaviours in exercised animals, without major differences depending on the exercise level. Effects on learning and memory processes were dependent on task and level of exercise. Two-way avoidance was not affected either in the acquisition or in the retention session, while the retention of object recognition task was affected. In this latter task, an enhancement in low running subjects and impairment in high and very-high running animals were observed.

  6. Effects of group music therapy on quality of life, affect, and participation in people with varying levels of dementia.

    Science.gov (United States)

    Solé, Carme; Mercadal-Brotons, Melissa; Galati, Adrián; De Castro, Mónica

    2014-01-01

    There is substantive literature reporting the importance and benefits of music and music therapy programs for older adults, and more specifically for those with dementia. However, few studies have focused on how these programs may contribute to quality of life. Objectives for this exploratory study were: (a) to evaluate the potential effect of group music therapy program participation on the quality of life of older people with mild, moderate, and severe dementia living in a nursing home; (b) to identify and analyze changes in affect and participation that take place during music therapy sessions; and (c) to suggest recommendations and strategies for the design of future music therapy studies with people in various stages of dementias. Sixteen participants (15 women; 1 man), with varying level of dementia participated in 12 weekly music therapy sessions. Based on Global Deterioration Scale (GDS) scores, phases of cognitive function were as follows: mild (n = 9; GDS 3-4), moderate (n = 5; GDS 5), and severe (n = 2; GDS 6-7). Data were collected using the GENCAT scale on Quality of Life. Sessions 1, 6, and 12 were also video recorded for post-hoc analysis of facial affect and participation behaviors. There was no significant difference in quality of life scores from pre to posttest (z = -0.824; p =0.410). However, there was a significant improvement in median subscale scores for Emotional Well-being (z = -2.176, p = 0.030), and significant worsening in median subscale scores for Interpersonal Relations (z =-2.074; p = 0.038) from pre to posttest. With regard to affect and participation, a sustained high level of participation was observed throughout the intervention program. Expressions of emotion remained low. Authors discuss implications of study findings to inform and improve future research in the areas of music therapy, quality of life, and individuals with dementia. © the American Music Therapy Association 2014. All rights reserved. For permissions, please e

  7. Modelling tourists arrival using time varying parameter

    Science.gov (United States)

    Suciptawati, P.; Sukarsa, K. G.; Kencana, Eka N.

    2017-06-01

    The importance of tourism and its related sectors to support economic development and poverty reduction in many countries increase researchers’ attentions to study and model tourists’ arrival. This work is aimed to demonstrate time varying parameter (TVP) technique to model the arrival of Korean’s tourists to Bali. The number of Korean tourists whom visiting Bali for period January 2010 to December 2015 were used to model the number of Korean’s tourists to Bali (KOR) as dependent variable. The predictors are the exchange rate of Won to IDR (WON), the inflation rate in Korea (INFKR), and the inflation rate in Indonesia (INFID). Observing tourists visit to Bali tend to fluctuate by their nationality, then the model was built by applying TVP and its parameters were approximated using Kalman Filter algorithm. The results showed all of predictor variables (WON, INFKR, INFID) significantly affect KOR. For in-sample and out-of-sample forecast with ARIMA’s forecasted values for the predictors, TVP model gave mean absolute percentage error (MAPE) as much as 11.24 percent and 12.86 percent, respectively.

  8. Online Activity Levels Are Related to Caffeine Dependency.

    Science.gov (United States)

    Phillips, James G; Landhuis, C Erik; Shepherd, Daniel; Ogeil, Rowan P

    2016-05-01

    Online activity could serve in the future as behavioral markers of emotional states for computer systems (i.e., affective computing). Hence, this study considered relationships between self-reported stimulant use and online study patterns. Sixty-two undergraduate psychology students estimated their daily caffeine use, and this was related to study patterns as tracked by their use of a Learning Management System (Blackboard). Caffeine dependency was associated with less time spent online, lower rates of file access, and fewer online activities completed. Reduced breadth or depth of processing during work/study could be used as a behavioral marker of stimulant use.

  9. Symmetry dependence of rms charge radii

    International Nuclear Information System (INIS)

    Angeli, I.

    2000-01-01

    Complete text of publication follows. The nucleon number dependence of rms charge radii is often approximated by some simple formula containing the mass number A only, R(A) = r(A) x A 1/3 where r(A) is a slowly varying function of A e.g. r(A) = r 0 + r 1 A -2/3 + r 2 A -4/3 ; r 0 , r 1 and r 2 are determined from a fit to experimental data. These simple mass-dependent formulae R(A) may be useful for nuclei along the valley of stability. However, for nuclei of the stability line, the mass number A = N + Z in itself is not enough to characterise the dependence of the R(Z,N) radius surface of the nucleon numbers Z and N. Changing a neutron to a proton a change in the charge radius can be expected, although A remains constant. In the present work, to extend the traditional radius formula, an additional term has been included, depending on the symmetry parameter I = (N-Z)/A. Several parametrisations were tried, using weighted least-squares (minimum χ 2 ) procedures for the fit to present-day data base (1). The best fit (with χ 2 /n'∼16) was found for R b (A,I) = r(A) x A 1/3 + b(I-I st ), where I st = (N st -Z st )/A is the value of the symmetry parameter of the stable isobar with the given mass number A, and b = -0.83. The alternative formula R a (A,I) = [r(A) + a(I-I st ) x A 1/3 is only slightly inferior to the previous one; here a = -0.20 and χ 2 /n'∼18. These results are practically independent of the ways of minimum search: fixing the parameters r 0 , r 1 and r 2 and varying teh parameter b (a) or varying the radius parameters r 0 , r 1 and r 2 and b (a) simultaneously. The main difficulty in determining the right parametrisation is caused by the fact that the experimental surface R exp (A,I) is not smooth. On the contrary, there are significant shell- and deformation effects (2,3) and isolated irregular points that may strongly affect the result of the fit. In order to avoid the effect of these strong deviations on the smooth symmetry dependence, more than

  10. Performance of juvenile mojarra supplied with feed containing varying levels of crude protein

    Directory of Open Access Journals (Sweden)

    Ricardo Henrique Bastos de Souza

    2016-04-01

    Full Text Available ABSTRACT The growth of the Brazilian aquaculture has stimulated the development of the productive chain of native species, including marine environment. The objective of this study was to evaluate the growth performance of juvenile mojarra fish (Diapterus rhombeus fed diets containing different concentrations of crude protein (32, 36, 40 and 44 g 100 g-1. The 80 juvenile mojarra (7.2±1.5 g were kept in 16 circular tanks (150 L. The study design used was completely randomized with four treatments and four repetitions. The fish were fed four times a day. At the end of the experiment (60 days the final weight, feed intake, weight gain (WG, feed:gain ratio (FGR, protein efficiency rate (PER, energy efficiency rate, specific growth, survival rate and, body composition were evaluated. It was verified significant effect of protein level on the WG, with the best value at the level of 38.20 g 100 g-1 of crude protein. For FGR, the best estimated value occurred with 38.06 g 100 g-1 of crude protein, similar to that reported for the PER (38.91 g 100 g-1. The other performance parameters and body composition were not influenced by crude protein levels. Diet crude protein concentrations between 38.06 and 38.91 g 100 g-1 provide the best performance indices for juvenile mojarra.

  11. Association of umbilical cord blood lead with neonatal behavior at varying levels of exposure

    Directory of Open Access Journals (Sweden)

    Mamtani Manju R

    2006-06-01

    Full Text Available Abstract Background In the light of the ongoing debate about lowering the cut-off for acceptable blood lead level to Methods Using Brazelton's Neonatal Behavioral Assessment Scale (NBAS, an epidemiological approach and robust statistical techniques like multivariate linear regression, logistic regression, Poisson regression and structural equations modeling analyses we estimated the simultaneous indirect effects of umbilical cord blood lead (CBL levels and other neonatal covariates on the NBAS clusters. Results We observed that when analyzed in all study subjects, the CBL levels independently and strongly influenced autonomic stability and abnormal reflexes clusters. However, when the analysis was restricted to neonates with CBL Conclusion Our results further endorse the need to be cognizant of the detrimental effects of blood lead on neonates even at a low-dose prenatal exposure.

  12. Working long hours: less productive but less costly? Firm-level evidence from Belgium

    OpenAIRE

    DELMEZ, Françoise; Vandenberghe, Vincent

    2017-01-01

    From the point of view of a profit-maximizing firm, the optimal number of working hours depends not only on the marginal productivity of hours but also on the marginal labour cost. This paper develops and assesses empirically a simple model of firms' decision making where productivity varies with hours and where the firm faces labour costs per worker that are invariant to the number of hours worked: i.e. quasi-fixed labour costs. Using Belgian firm-level data on production, labour costs, work...

  13. Shear-Rate-Dependent Behavior of Clayey Bimaterial Interfaces at Landslide Stress Levels

    Science.gov (United States)

    Scaringi, Gianvito; Hu, Wei; Xu, Qiang; Huang, Runqiu

    2018-01-01

    The behavior of reactivated and first-failure landslides after large displacements is controlled by the available shear resistance in a shear zone and/or along slip surfaces, such as a soil-bedrock interface. Among the factors influencing the resistance parameter, the dependence on the shear rate can trigger catastrophic evolution (rate-weakening) or exert a slow-down feedback (rate-strengthening) upon stress perturbation. We present ring-shear test results, performed under various normal stresses and shear rates, on clayey soils from a landslide shear zone, on its parent lithology and other lithologies, and on clay-rock interface samples. We find that depending on the materials in contact, the normal stress, and the stress history, the shear-rate-dependent behaviors differ. We discuss possible models and underlying mechanisms for the time-dependent behavior of landslides in clay soils.

  14. Fitness Effects of Chlorpyrifos in the Damselfly Enallagma cyathigerum Strongly Depend upon Temperature and Food Level and Can Bridge Metamorphosis

    Science.gov (United States)

    Janssens, Lizanne; Stoks, Robby

    2013-01-01

    Interactions between pollutants and suboptimal environmental conditions can have severe consequences for the toxicity of pollutants, yet are still poorly understood. To identify patterns across environmental conditions and across fitness-related variables we exposed Enallagma cyathigerum damselfly larvae to the pesticide chlorpyrifos at two food levels or at two temperatures and quantified four fitness-related variables (larval survival, development time, mass at emergence and adult cold resistance). Food level and temperature did not affect survival in the absence of the pesticide, yet the pesticide reduced survival only at the high temperature. Animals reacted to the pesticide by accelerating their development but only at the high food level and at the low temperature; at the low food level, however, pesticide exposure resulted in a slower development. Chlorpyrifos exposure resulted in smaller adults except in animals reared at the high food level. Animals reared at the low food level and at the low temperature had a higher cold resistance which was not affected by the pesticide. In summary our study highlight that combined effects of exposure to chlorpyrifos and the two environmental conditions (i) were mostly interactive and sometimes even reversed in comparison with the effect of the environmental condition in isolation, (ii) strongly differed depending on the fitness-related variable under study, (iii) were not always predictable based on the effect of the environmental condition in isolation, and (iv) bridged metamorphosis depending on which environmental condition was combined with the pesticide thereby potentially carrying over from aquatic to terrestrial ecosystems. These findings are relevant when extrapolating results of laboratory tests done under ideal environmental conditions to natural communities. PMID:23840819

  15. Fitness Effects of Chlorpyrifos in the Damselfly Enallagma cyathigerum Strongly Depend upon Temperature and Food Level and Can Bridge Metamorphosis.

    Directory of Open Access Journals (Sweden)

    Lizanne Janssens

    Full Text Available Interactions between pollutants and suboptimal environmental conditions can have severe consequences for the toxicity of pollutants, yet are still poorly understood. To identify patterns across environmental conditions and across fitness-related variables we exposed Enallagma cyathigerum damselfly larvae to the pesticide chlorpyrifos at two food levels or at two temperatures and quantified four fitness-related variables (larval survival, development time, mass at emergence and adult cold resistance. Food level and temperature did not affect survival in the absence of the pesticide, yet the pesticide reduced survival only at the high temperature. Animals reacted to the pesticide by accelerating their development but only at the high food level and at the low temperature; at the low food level, however, pesticide exposure resulted in a slower development. Chlorpyrifos exposure resulted in smaller adults except in animals reared at the high food level. Animals reared at the low food level and at the low temperature had a higher cold resistance which was not affected by the pesticide. In summary our study highlight that combined effects of exposure to chlorpyrifos and the two environmental conditions (i were mostly interactive and sometimes even reversed in comparison with the effect of the environmental condition in isolation, (ii strongly differed depending on the fitness-related variable under study, (iii were not always predictable based on the effect of the environmental condition in isolation, and (iv bridged metamorphosis depending on which environmental condition was combined with the pesticide thereby potentially carrying over from aquatic to terrestrial ecosystems. These findings are relevant when extrapolating results of laboratory tests done under ideal environmental conditions to natural communities.

  16. Age-dependent effect of every-other-day feeding and aerobic exercise in ubiquinone levels and related antioxidant activities in mice muscle.

    Science.gov (United States)

    Rodríguez-Bies, Elizabeth; Navas, Plácido; López-Lluch, Guillermo

    2015-01-01

    Aging affects many biochemical, cellular, and physiological processes in the organisms. Accumulation of damage based on oxidized macromolecules is found in many age-associated diseases. Coenzyme Q (Q) is one of the main molecules involved in metabolic and antioxidant activities in cells. Q-dependent antioxidant activities are importantly involved on the protection of cell membranes against oxidation. Many studies indicate that Q decay in most of the organs during aging. In our study, no changes in Q levels were found in old animals in comparison with young animals. On the other hand, the interventions, caloric restriction based on every-other-day feeding procedure, and physical exercise were able to increase Q levels in muscle, but only in old and not in young animals. Probably, this effect prevented the increase in lipid peroxidation found in aged animals and also protein carbonylation. Further, Q-dependent antioxidant activities such as NADH-cytochrome b5 reductase and NAD(P)H-quinone oxidoreductase 1 are also modulated by both exercise and every other day feeding. Taken together, we demonstrate that exercise and dietary restriction as every-other-day procedure can regulate endogenous synthesized Q levels and Q-dependent antioxidant activities in muscle, preventing oxidative damage in aged muscle. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Supporting Space Systems Design via Systems Dependency Analysis Methodology

    Science.gov (United States)

    Guariniello, Cesare

    The increasing size and complexity of space systems and space missions pose severe challenges to space systems engineers. When complex systems and Systems-of-Systems are involved, the behavior of the whole entity is not only due to that of the individual systems involved but also to the interactions and dependencies between the systems. Dependencies can be varied and complex, and designers usually do not perform analysis of the impact of dependencies at the level of complex systems, or this analysis involves excessive computational cost, or occurs at a later stage of the design process, after designers have already set detailed requirements, following a bottom-up approach. While classical systems engineering attempts to integrate the perspectives involved across the variety of engineering disciplines and the objectives of multiple stakeholders, there is still a need for more effective tools and methods capable to identify, analyze and quantify properties of the complex system as a whole and to model explicitly the effect of some of the features that characterize complex systems. This research describes the development and usage of Systems Operational Dependency Analysis and Systems Developmental Dependency Analysis, two methods based on parametric models of the behavior of complex systems, one in the operational domain and one in the developmental domain. The parameters of the developed models have intuitive meaning, are usable with subjective and quantitative data alike, and give direct insight into the causes of observed, and possibly emergent, behavior. The approach proposed in this dissertation combines models of one-to-one dependencies among systems and between systems and capabilities, to analyze and evaluate the impact of failures or delays on the outcome of the whole complex system. The analysis accounts for cascading effects, partial operational failures, multiple failures or delays, and partial developmental dependencies. The user of these methods can

  18. Carbon translocation from symbiont to host depends on irradiance and food availability in the tropical coral Stylophora pistillata

    Science.gov (United States)

    Tremblay, P.; Grover, R.; Maguer, J. F.; Hoogenboom, M.; Ferrier-Pagès, C.

    2014-03-01

    Reef-building corals live in symbiosis with dinoflagellates that translocate a large proportion of their photosynthetically fixed carbon compounds to their coral host for its own metabolism. The carbon budget and translocation rate, however, vary depending on environmental conditions, coral host species, and symbiont clade. To quantify variability in carbon translocation in response to environmental conditions, this study assessed the effect of two different irradiance levels (120 and 250 μmol photons m-2 s-1) and feeding regimes (fed with Artemia salina nauplii and unfed) on the carbon budget of the tropical coral Stylophora pistillata. For this purpose, H13CO3 --enriched seawater was used to trace the conversion of photosynthetic carbon into symbiont and coral biomass and excrete particulate organic carbon. Results showed that carbon translocation (ca. 78 %) and utilization were similar under both irradiance levels for unfed colonies. In contrast, carbon utilization by fed colonies was dependent on the growth irradiance. Under low irradiance, heterotrophy was accompanied by lower carbon translocation (71 %), higher host and symbiont biomass, and higher calcification rates. Under high irradiance, heterotrophy was accompanied by higher rates of photosynthesis, respiration, and carbon translocation (90 %) as well as higher host biomass. Hence, levels of resource sharing within coral-dinoflagellate symbioses depend critically on environmental conditions.

  19. Energy spectrum of two-dimensional tight-binding electrons in a spatially varying magnetic field

    International Nuclear Information System (INIS)

    Oh, G.Y.; Lee, M.H.

    1996-01-01

    The electronic energy spectrum of a two-dimensional lattice in a spatially varying magnetic field is studied within the framework of the tight-binding model by using the scheme of the transfer matrix. It is found that, in comparison with the case of a uniform magnetic field, the energy spectrum exhibits more complicated behavior; band broadening (or gap closing) and band splitting (or gap opening) occur depending on characteristic parameters of the lattice. The origin of these phenomena lies in the existence of direct touching and indirect overlapping between neighboring subbands. Dependence of direct touching and indirect overlapping, and thus the electronic band structure together with the density of states, on characteristic parameters of the lattice is elucidated in detail. copyright 1996 The American Physical Society

  20. Dopamine D1 receptor-dependent regulation of extracellular citrulline level in the rat nucleus accumbens during conditioned fear response.

    Science.gov (United States)

    Saulskaya, Natalia B; Fofonova, Nellia V; Sudorghina, Polina V; Saveliev, Sergey A

    2008-08-01

    Nucleus accumbens (N.Acc) contains a subclass of nitric oxide (NO)-generating interneurons that are presumably regulated by the dopamine input. Receptor mechanisms underlying dopamine-NO interaction in the N.Acc are poorly understood. In the current study, we used in vivo microdialysis combined with high-performance liquid chromatography to examine participation of dopamine D1 receptors in regulation of extracellular levels of citrulline (an NO co-product) in the medial N.Acc of Sprague-Dawley rats during both pharmacological challenge and a conditioned fear response. The intraaccumbal infusion of the D1 receptor agonist SKF-38393 (100-500 microM) increased dose-dependently the local dialysate citrulline levels. The SKF-38393-induced increase in extracellular citrulline was prevented by intraaccumbal infusions of 500 microM 7-nitroindazole, a neuronal NO synthase inhibitor. In behavioral microdialysis experiment, the accumbal levels of extracellular citrulline markedly increased in rats given a mild footshock paired with tone. The presentation of the tone previously paired with footshock (the conditioned fear response) produced a "conditioned" rise of extracellular citrulline levels in the N.Acc which was attenuated by intraaccumbal infusion of 100 microM SCH-23390, a dopamine D1 receptor antagonist, and prevented by intraaccumbal infusion of 500 microM 7-nitroindazole. The results suggest that in the N.Acc, the dopamine D1 receptors might regulate the neuronal NO synthase activity; this dopamine-dependent mechanism seems to participate in activation of the neuronal NO synthase and probably NO formation in this brain area during the conditioned fear response.