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Sample records for resistive loss models

  1. Resist loss in 3D compact modeling

    Science.gov (United States)

    Zheng, Xin; Huang, Jensheng; Chin, Fook; Kazarian, Aram; Kuo, Chun-Chieh

    2012-03-01

    An enhancement to compact modeling capability to include photoresist (PR) loss at different heights is developed and discussed. A hypsometric map representing 3-D resist profile was built by applying a first principle approximation to estimate the "energy loss" from the resist top to any other plane of interest as a proportional corresponding change in model threshold, which is analogous to a change in exposure dose. The result is compared and validated with 3D rigorous modeling as well as SEM images. Without increase in computation time, this compact model can construct 3D resist profiles capturing resist profile degradation at any vertical plane. Sidewall angle and standing wave information can also be granted from the vertical profile reconstruction. Since this method does not change any form of compact modeling, it can be integrated to validation and correction without any additional work.

  2. Physical calculations of resistance to water loss improve species range models: Reply.

    Science.gov (United States)

    Riddell, Eric A; Sears, Michael W

    2017-09-13

    Christian et al. (2017) proposed several possible flaws in the methods and logic presented by Riddell et al. (2017) that included potential activity of salamanders during measurements, trimming of the agar model's legs, misinterpretations of the empirical data, limitations on agar models, and the relationship between body size and skin resistance to water loss (ri ). We argue that these criticisms are easily addressable, and here, we reinforce our original claim that the agar method for determination of resistance to water loss is flawed. Before responding to these individual critiques, we begin with a deeper criticism of the agar model method and general methodology for determining resistance to water loss that has resulted in the reification of the boundary layer's ecological and physiological importance. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  3. A Two-Dimensional Modeling Procedure to Estimate the Loss Equivalent Resistance Including the Saturation Effect

    Directory of Open Access Journals (Sweden)

    Rosa Ana Salas

    2013-11-01

    Full Text Available We propose a modeling procedure specifically designed for a ferrite inductor excited by a waveform in time domain. We estimate the loss resistance in the core (parameter of the electrical model of the inductor by means of a Finite Element Method in 2D which leads to significant computational advantages over the 3D model. The methodology is validated for an RM (rectangular modulus ferrite core working in the linear and the saturation regions. Excellent agreement is found between the experimental data and the computational results.

  4. Validation of airway resistance models for predicting pressure loss through anatomically realistic conducting airway replicas of adults and children.

    Science.gov (United States)

    Borojeni, Azadeh A T; Noga, Michelle L; Martin, Andrew R; Finlay, Warren H

    2015-07-16

    This work describes in vitro measurement of the total pressure loss at varying flow rate through anatomically realistic conducting airway replicas of 10 children, 4 to 8 years old, and 5 adults. Experimental results were compared with analytical predictions made using published airway resistance models. For the adult replicas, the model proposed by van Ertbruggen et al. (2005. J. Appl. Physiol. 98, 970-980) most accurately predicted central conducting airway resistance for inspiratory flow rates ranging from 15 to 90 L/min. Models proposed by Pedley et al. (1970. J. Respir. Physiol. 9, 371-386) and by Katz et al. (2011. J. Biomech. 44, 1137-1143) also provided reasonable estimates, but with a tendency to over predict measured pressure loss for both models. For child replicas, the Pedley and Katz models both provided good estimation of measured pressure loss at flow rates representative of resting tidal breathing, but under predicted measured values at high inspiratory flow rate (60 L/min). The van Ertbruggen model, developed based on flow simulations performed in an adult airway model, tended to under predict measured pressure loss through the child replicas across the range of flow rates studied (2 to 60 L/min). These results are intended to provide guidance for selection of analytical pressure loss models for use in predicting airway resistance and ventilation distribution in adults and children. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Computer Aided Modeling to Determine the Effectiveness of Resistive Exercises as Countermeasures for Bone Mineral Density Loss

    Science.gov (United States)

    Murphy, Benjamin M.

    1999-01-01

    Due to the loss of gravitational loading, astronauts have a tendency to lose bone mineral density in their lumbar spine and lower extremities on orbit. NASA requires astronauts to perform exercises during space flight to help reduce the amount of demineralization. To test these exercises on earth, 17 week bed rest studies are conducted that consist of specific diet and exercise regimes. Developing a finite element model of these exercises will help to quantify the stress distribution imposed by of each of these exercises. To help develop this model, MRI images are acquired from individuals participating in the bed rest studies. The MRIs can be used to create a subject specific model of each individual for testing. The MRIs are processed in the Magnetic Resonance Imaging Data Transfer System program to develop a three-dimensional finite element model of the femur for evaluation. Modifications were made to the MRIDTS that simplified the model creation process. These modifications made it possible to construct two separate models of different portions of a bone simultaneously and then later connect them manually. This helped alleviate the warping problem associated with the drastic changes in geometry found in some body parts, such as the joints. The code was also modified to incorporate material properties of various bone components into the model. Interior meshing was also incorporated into the program to allow for both the cortical shell and the entire bone to be modeled. A prototype model of the right femur of an adult female is being constructed and tested to determine the feasibility of finite element analysis as a tool for evaluating exercise effectiveness. The model is being run through the ANSYS finite element program on the Alabama Super Computer Network. After the model is validated, models of bedrest subjects can be generated to investigate exercise countermeasures.

  6. Modelling Vocabulary Loss

    Science.gov (United States)

    Meara, Paul

    2004-01-01

    This paper describes some simple simulation models of vocabulary attrition. The attrition process is modelled using a random autonomous Boolean network model, and some parallels with real attrition data are drawn. The paper argues that applying a complex systems approach to attrition can provide some important insights, which suggest that real…

  7. Inducible models of bone loss.

    Science.gov (United States)

    Doucette, Casey R; Rosen, Clifford J

    2014-12-11

    Bone is an essential organ that not only confers structural stability to the organism, but also serves as a reservoir for hematopoietic elements and is thought to affect systemic homeostasis through the release of endocrine factors as well as calcium. The loss of bone mass due to an uncoupling of bone formation and bone resorption leads to increased fragility that can result in devastating fractures. Further understanding of the effects of environmental stimuli on the development of bone disease in humans is needed, and they can be studied using animal models. Here, we present established and novel methods for the induction of bone loss in mice, including manipulation of diet and environment, administration of drugs, irradiation, and surgically induced hormone deficiency. All of these models are directly related to human cases, and thus, can be used to investigate the causes of bone loss resulting from these interventions. Copyright © 2014 John Wiley & Sons, Inc.

  8. Flood Loss Model for Austria

    Science.gov (United States)

    Punčochář, P.; Podlaha, A.

    2012-04-01

    A new flood model for Austria quantifying fluvial flood losses based on probabilistic event set developed by Impact Forecasting (Aon Benfield's model development centre) was released in June 2011. It was successfully validated with two serious past flood events - August 2002 and August 2005. The model is based on 10 meters cell size digital terrain model with 1cm vertical step and uses daily mean flows from 548 gauge stations of series of average length ~ 60 years. The even set is based on monthly maxima flows correlation, generating 12 stochastic events per year and allows to calculate annual and occurrence exceedance probability loss estimates. The model contains flood extents for more than 24,000 km of modelled river network compatible with HORA project (HOchwasserRisikoflächen Austria) for design flows ranging from 2 to 10,000 years. Model is primarily constructed to work with postal level resolution insurance data reducing positional uncertainty by weighting over more than 2.5 millions address points from Austria Post's ACGeo database. Countrywide flood protections were provided by the Austrian Ministry of Environment. The model was successfully tested with property portfolios of 8 global and local insurance companies and was also successfully validated with August 2002 and August 2005 past events evaluating their return period on the probabilistic simulation basis.

  9. Optimal battery charging, Part I: Minimizing time-to-charge, energy loss, and temperature rise for OCV-resistance battery model

    Science.gov (United States)

    Abdollahi, A.; Han, X.; Avvari, G. V.; Raghunathan, N.; Balasingam, B.; Pattipati, K. R.; Bar-Shalom, Y.

    2016-01-01

    In this paper we present a closed-form solution to the problem of optimally charging a Li-ion battery. A combination of three cost functions is considered as the objective function: time-to-charge (TTC), energy losses (EL), and a temperature rise index (TRI). First, we consider the cost function of the optimization problem as a weighted sum of TTC and EL. We show that the optimal charging strategy in this case is the well-known Constant Current-Constant Voltage (CC-CV) policy with the value of the current in the CC stage being a function of the ratio of weighting on TTC and EL and of the resistance of the battery. Then, we extend the cost function to a weighted sum of TTC, EL and TRI and derive an analytical solution for the problem. It is shown that the analytical solution can be approximated by a CC-CV with the value of current in the CC stage being a function of ratio of weighting on TTC and EL, resistance of the battery and the effective thermal resistance.

  10. Loss of ovarian function in the VCD mouse-model of menopause leads to insulin resistance and a rapid progression into the metabolic syndrome.

    Science.gov (United States)

    Romero-Aleshire, Melissa J; Diamond-Stanic, Maggie K; Hasty, Alyssa H; Hoyer, Patricia B; Brooks, Heddwen L

    2009-09-01

    Factors comprising the metabolic syndrome occur with increased incidence in postmenopausal women. To investigate the effects of ovarian failure on the progression of the metabolic syndrome, female B(6)C(3)F(1) mice were treated with 4-vinylcyclohexene diepoxide (VCD) and fed a high-fat (HF) diet for 16 wk. VCD destroys preantral follicles, causing early ovarian failure and is a well-characterized model for the gradual onset of menopause. After 12 wk on a HF diet, VCD-treated mice had developed an impaired glucose tolerance, whereas cycling controls were unaffected [12 wk AUC HF mice 13,455 +/- 643 vs. HF/VCD 17,378 +/- 1140 mg/dl/min, P diet, VCD-treated mice had significantly higher fasting insulin levels (HF 5.4 +/- 1.3 vs. HF/VCD 10.1 +/- 1.4 ng/ml, P diet (HF 56.2 +/- 16.7 vs. HF/VCD 113.1 +/- 19.6 mg/dl x microU/ml, P diet gained more weight than mice on a standard diet, and weight gain in HF/VCD mice was significantly increased compared with HF cycling controls. Interestingly, even without a HF diet, progression into VCD-induced menopause caused a significant increase in cholesterol and free fatty acids. Furthermore, in mice fed a standard diet (6% fat), insulin resistance developed 4 mo after VCD-induced ovarian failure. Insulin resistance following ovarian failure (menopause) was prevented by estrogen replacement. Studies here demonstrate that ovarian failure (menopause) accelerates progression into the metabolic syndrome and that estrogen replacement prevents the onset of insulin resistance in VCD-treated mice. Thus, the VCD model of menopause provides a physiologically relevant means of studying how sex hormones influence the progression of the metabolic syndrome.

  11. Optimal Battery Charging, Part 1: Minimizing Time-to-Charge, Energy Loss, and Temperature Rise for OCV-Resistance Battery Model

    Science.gov (United States)

    2015-02-18

    resistance R0 in model I. The batteries are Samsung EB575152 (four cells), Samsung EB504465 (four cells), Samsung AB463651 (two cells), Nokia BP-4L (four cells...commercial batteries. Make Model Cell# R0 (mU) R1 (mU) C1 (F) a Cbatt (Ah) Samsung EB575152 1 253 106 4581 0.997934 1.1875 Samsung EB575152 2 209 94 5203...0.997962 1.2187 Samsung EB575152 3 418 58 6222 0.99724 1.2001 Samsung EB575152 4 200 142 3046 0.997689 1.485 Samsung EB504465 1 259 106 4598 0.997941

  12. The Credibility Models under LINEX Loss Functions

    Institute of Scientific and Technical Information of China (English)

    WEN Li-min; ZHANG Xian-kun; ZHENG Dan; FANG Jing

    2012-01-01

    LINEX(linear and exponential) loss function is a useful asymmetric loss function.The purpose of using a LINEX loss function in credibility models is to solve the problem of very high premium by suing a symmetric quadratic loss function in most of classical credibility models. The Bayes premium and the credibility premium are derived under LINEX loss function. The consistency of Bayes premium and credibility premium were also checked.Finally,the simulation was introduced to show the differences between the credibility estimator we derived and the classical one.

  13. Cross-Characterization for Imaging Parasitic Resistive Losses in Thin-Film Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    Archana Sinha

    2016-08-01

    Full Text Available Thin-film photovoltaic (PV modules often suffer from a variety of parasitic resistive losses in transparent conductive oxide (TCO and absorber layers that significantly affect the module electrical performance. This paper presents the holistic investigation of resistive effects due to TCO lateral sheet resistance and shunts in amorphous-silicon (a-Si thin-film PV modules by simultaneous use of three different imaging techniques, electroluminescence (EL, lock-in thermography (LIT and light beam induced current (LBIC, under different operating conditions. Results from individual techniques have been compared and analyzed for particular type of loss channel, and combination of these techniques has been used to obtain more detailed information for the identification and classification of these loss channels. EL and LIT techniques imaged the TCO lateral resistive effects with different spatial sensitivity across the cell width. For quantification purpose, a distributed diode modeling and simulation approach has been exploited to estimate TCO sheet resistance from EL intensity pattern and effect of cell width on module efficiency. For shunt investigation, LIT provided better localization of severe shunts, while EL and LBIC given good localization of weak shunts formed by the scratches. The impact of shunts on the photocurrent generation capability of individual cells has been assessed by li-LBIC technique. Results show that the cross-characterization by different imaging techniques provides additional information, which aids in identifying the nature and severity of loss channels with more certainty, along with their relative advantages and limitations in particular cases.

  14. Probabilistic, meso-scale flood loss modelling

    Science.gov (United States)

    Kreibich, Heidi; Botto, Anna; Schröter, Kai; Merz, Bruno

    2016-04-01

    Flood risk analyses are an important basis for decisions on flood risk management and adaptation. However, such analyses are associated with significant uncertainty, even more if changes in risk due to global change are expected. Although uncertainty analysis and probabilistic approaches have received increased attention during the last years, they are still not standard practice for flood risk assessments and even more for flood loss modelling. State of the art in flood loss modelling is still the use of simple, deterministic approaches like stage-damage functions. Novel probabilistic, multi-variate flood loss models have been developed and validated on the micro-scale using a data-mining approach, namely bagging decision trees (Merz et al. 2013). In this presentation we demonstrate and evaluate the upscaling of the approach to the meso-scale, namely on the basis of land-use units. The model is applied in 19 municipalities which were affected during the 2002 flood by the River Mulde in Saxony, Germany (Botto et al. submitted). The application of bagging decision tree based loss models provide a probability distribution of estimated loss per municipality. Validation is undertaken on the one hand via a comparison with eight deterministic loss models including stage-damage functions as well as multi-variate models. On the other hand the results are compared with official loss data provided by the Saxon Relief Bank (SAB). The results show, that uncertainties of loss estimation remain high. Thus, the significant advantage of this probabilistic flood loss estimation approach is that it inherently provides quantitative information about the uncertainty of the prediction. References: Merz, B.; Kreibich, H.; Lall, U. (2013): Multi-variate flood damage assessment: a tree-based data-mining approach. NHESS, 13(1), 53-64. Botto A, Kreibich H, Merz B, Schröter K (submitted) Probabilistic, multi-variable flood loss modelling on the meso-scale with BT-FLEMO. Risk Analysis.

  15. An Auditory Model with Hearing Loss

    DEFF Research Database (Denmark)

    Nielsen, Lars Bramsløw

    An auditory model based on the psychophysics of hearing has been developed and tested. The model simulates the normal ear or an impaired ear with a given hearing loss. Based on reviews of the current literature, the frequency selectivity and loudness growth as functions of threshold and stimulus...... level have been found and implemented in the model. The auditory model was verified against selected results from the literature, and it was confirmed that the normal spread of masking and loudness growth could be simulated in the model. The effects of hearing loss on these parameters was also...... in qualitative agreement with recent findings. The temporal properties of the ear have currently not been included in the model. As an example of a real-world application of the model, loudness spectrograms for a speech utterance were presented. By introducing hearing loss, the speech sounds became less audible...

  16. Loss Given Default Modelling: Comparative Analysis

    OpenAIRE

    Yashkir, Olga; Yashkir, Yuriy

    2013-01-01

    In this study we investigated several most popular Loss Given Default (LGD) models (LSM, Tobit, Three-Tiered Tobit, Beta Regression, Inflated Beta Regression, Censored Gamma Regression) in order to compare their performance. We show that for a given input data set, the quality of the model calibration depends mainly on the proper choice (and availability) of explanatory variables (model factors), but not on the fitting model. Model factors were chosen based on the amplitude of their correlati...

  17. Thermomechanical Modelling of Resistance Welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi

    2007-01-01

    The present paper describes a generic programme for analysis, optimization and development of resistance spot and projection welding. The programme includes an electrical model determining electric current and voltage distribution as well as heat generation, a thermal model calculating heat...

  18. Data Acquisition for Quality Loss Function Modelling

    DEFF Research Database (Denmark)

    Pedersen, Søren Nygaard; Howard, Thomas J.

    2016-01-01

    Quality loss functions can be a valuable tool when assessing the impact of variation on product quality. Typically, the input for the quality loss function would be a measure of the varying product performance and the output would be a measure of quality. While the unit of the input is given by t...... by the product function in focus, the quality output can be measured and quantified in a number of ways. In this article a structured approach for acquiring stakeholder satisfaction data for use in quality loss function modelling is introduced.......Quality loss functions can be a valuable tool when assessing the impact of variation on product quality. Typically, the input for the quality loss function would be a measure of the varying product performance and the output would be a measure of quality. While the unit of the input is given...

  19. Data Acquisition for Quality Loss Function Modelling

    DEFF Research Database (Denmark)

    Pedersen, Søren Nygaard; Howard, Thomas J.

    2016-01-01

    Quality loss functions can be a valuable tool when assessing the impact of variation on product quality. Typically, the input for the quality loss function would be a measure of the varying product performance and the output would be a measure of quality. While the unit of the input is given by t...... by the product function in focus, the quality output can be measured and quantified in a number of ways. In this article a structured approach for acquiring stakeholder satisfaction data for use in quality loss function modelling is introduced.......Quality loss functions can be a valuable tool when assessing the impact of variation on product quality. Typically, the input for the quality loss function would be a measure of the varying product performance and the output would be a measure of quality. While the unit of the input is given...

  20. Modeling Loss Amplification After Devastating Disasters

    Science.gov (United States)

    Boissonnade, A. C.; Muir Wood, R.

    2008-05-01

    With the catastrophic events that occurred in 2004 and 2005 came the realization that Catastrophic (Cat) loss models were not properly modeling insured losses and their associated uncertainty. One reason was that major catastrophes were generally characterized by losses caused by the primary initiating events. Such approaches are not adequate when losses can result from the compounded impacts of scenarios of secondary cascading events (physical, economic, social and political) that can have much larger impacts than those due to the primary events themselves. Situations where more and more cascading events can occur will result in different outcomes, some leading to extreme loss events, generally referred as Super Cats. These situations occurred in December 2004 with the Sumatra earthquake and tsunami and in August 2005 with hurricane Katrina and resulting New Orleans flooding. A review of historical events shows that these events are not exceptions. Modeling such scenarios adds new levels of complexity and different perspectives in the understanding of characterizing and assessing impacts of catastrophic events. Modeling economic consequences of extreme events can be improved by developing scenarios of cascades of secondary events triggered by the primary event(s). The likelihood of each scenario should be modeled, along with the hazards of primary and secondary events and resulting losses with their impacts to the different stakeholders. In addition, it is also important to model the impacts of the hazards on the infrastructure and the resulting disruption to the residents and the local economy because these can result in additional losses. This paper describes current work with the goals of better modeling the full economic impacts from catastrophic events, and of a more comprehensive treatment of uncertainty. We will present approaches for modeling loss amplification that account for all the ways in which the cost incurred for a certain level of damage due to a

  1. Loss models for long Josephson junctions

    DEFF Research Database (Denmark)

    Olsen, O. H.; Samuelsen, Mogens Rugholm

    1984-01-01

    A general model for loss mechanisms in long Josephson junctions is presented. An expression for the zero-field step is found for a junction of overlap type by means of a perturbation method. Comparison between analytic solution and perturbation result shows good agreement.......A general model for loss mechanisms in long Josephson junctions is presented. An expression for the zero-field step is found for a junction of overlap type by means of a perturbation method. Comparison between analytic solution and perturbation result shows good agreement....

  2. Effects of diet composition on weight loss, metabolic factors and biomarkers in a 1-year weight loss intervention in obese women examined by baseline insulin resistance status.

    Science.gov (United States)

    Rock, Cheryl L; Flatt, Shirley W; Pakiz, Bilge; Quintana, Elizabeth L; Heath, Dennis D; Rana, Brinda K; Natarajan, Loki

    2016-11-01

    Obesity is a risk factor for postmenopausal breast cancer incidence and premenopausal and postmenopausal breast cancer mortality, which may be explained by several metabolic and hormonal factors (sex hormones, insulin resistance, and inflammation) that are biologically related. Differential effects of dietary composition on weight loss and these metabolic factors may occur in insulin-sensitive vs. insulin-resistant obese women. To examine the effect of diet composition on weight loss and metabolic, hormonal and inflammatory factors in overweight/obese women stratified by insulin resistance status in a 1-year weight loss intervention. Nondiabetic women who were overweight/obese (n=245) were randomly assigned to a lower fat (20% energy), higher carbohydrate (65% energy) diet; a lower carbohydrate (45% energy), higher fat (35% energy) diet; or a walnut-rich (18% energy), higher fat (35% energy), lower carbohydrate (45% energy) diet. All groups lost weight at follow-up (Pdiet×time×insulin resistance status interaction was not statistically significant in the model for overall weight loss, although insulin sensitive women at 12months lost more weight in the lower fat vs. lower carbohydrate group (7.5kg vs. 4.3kg, P=0.06), and in the walnut-rich vs. lower carbohydrate group (8.1kg vs. 4.3kg, P=0.04). Sex hormone binding globulin increased within each group except in the lower carbohydrate group at 12months (Pdiet composition on weight loss depending on insulin resistance status. Prescribing walnuts is associated with weight loss comparable to a standard lower fat diet in a behavioral weight loss intervention. Weight loss itself may be the most critical factor for reducing the chronic inflammation associated with increased breast cancer risk and progression. Copyright © 2016. Published by Elsevier Inc.

  3. Computational Modeling of Fluorescence Loss in Photobleaching

    DEFF Research Database (Denmark)

    Hansen, Christian Valdemar; Schroll, Achim; Wüstner, Daniel

    2015-01-01

    Fluorescence loss in photobleaching (FLIP) is a modern microscopy method for visualization of transport processes in living cells. Although FLIP is widespread, an automated reliable analysis of image data is still lacking. This paper presents a framework for modeling and simulation of FLIP...

  4. Individual Hearing Loss: Characterization, Modelling, Compensation Strategies

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten; Christensen-Dalsgaard, Jakob;

    2016-01-01

    account for such individual differences, which make it challenging to find adequate compensation strategies in hearing devices. How to characterize, model, and compensate for individual hearing loss were the main topics of the fifth International Symposium on Auditory and Audiological Research (ISAAR...

  5. Individual Hearing Loss: Characterization, Modelling, Compensation Strategies

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten; Christensen-Dalsgaard, Jakob

    2016-01-01

    It is well-established that hearing loss does not only lead to a reduction of hearing sensitivity. Large individual differences are typically observed among listeners with hearing impairment in a wide range of suprathreshold auditory measures. In many cases, audiometric thresholds cannot fully...... account for such individual differences, which make it challenging to find adequate compensation strategies in hearing devices. How to characterize, model, and compensate for individual hearing loss were the main topics of the fifth International Symposium on Auditory and Audiological Research (ISAAR...

  6. A Technique to Estimate the Equivalent Loss Resistance of Grid-Tied Converters for Current Control Analysis and Design

    DEFF Research Database (Denmark)

    Vidal, Ana; Yepes, Alejandro G.; Fernandez, Francisco Daniel Freijedo

    2015-01-01

    Rigorous analysis and design of the current control loop in voltage source converters (VSCs) requires an accurate modeling. The loop behavior can be significantly influenced by the VSC working conditions. To consider such effect, converter losses should be included in the model, which can be done...... by means of an equivalent series resistance. This paper proposes a method to identify the VSC equivalent loss resistance for the proper tuning of the current control loop. It is based on analysis of the closed-loop transient response provided by a synchronous proportional-integral current controller......, according to the internal model principle. The method gives a set of loss resistance values linked to working conditions, which can be used to improve the tuning of the current controllers, either by online adaptation of the controller gains or by open-loop adaptive adjustment of them according to prestored...

  7. Bone Loss During Spaceflight: Available Models and Counter-Measures

    Science.gov (United States)

    Morris, Jonathan; Bach, David; Geller, David

    2015-01-01

    There is ongoing concern for human health during spaceflights. Of particular interest is the uncoupling of bone remodeling and its resultant effect on calcium metabolism and bone loss. The calculated average loss of bone mineral density (BMD) is approximately 1-1.5% per month of spaceflight. The effect of decreased BMD on associated fractures in astronauts is not known. Currently on the International Space Station (ISS), bone loss is managed through dietary supplements and modifications and resistance exercise regimen. As the duration of space flights increases, a review of the current methods available for the prevention of bone loss is warranted. The goal of this project is to review and summarize recent studies that have focused on maintaining BMD during exposure to microgravity. Interventions were divided into physical (Table 1), nutritional (Table 2), or pharmacologic (Table 3) categories. Physical modalities included resistance exercise, low level vibration, and low intensity pulsed ultrasound. Nutritional interventions included altering protein, salt, and fat intake; and vitamin D supplementation. Pharmacologic interventions included the use of bisphosphonates and beta blockers. Studies reported outcomes based on bone density determined by DXA bone scan, micro-architecture of histology and microCT, and serum and urine markers of bone turnover. The ground analog models utilized to approximate osseous physiology in microgravity included human patients previously paralyzed or subjects confined to bedrest. Ground analog animal models include paralysis, immobilization and ovariectomies. As a result of the extensive research performed there is a multi-modality approach available for the management of BMD during spaceflight that includes resistance training, nutrition and dietary supplements. However, there is a paucity of literature describing a formalized tiered protocol to guide investigators through the progression from animal models to human patient ground

  8. Blackhole evaporation model without information loss

    CERN Document Server

    Villegas, Kristian Hauser A

    2016-01-01

    A simple model of a blackhole evaporation without information loss is given. In this model, the blackhole is \\textit{not} in a specific mass eigenstate as it evaporates but rather, is in a superposition of various mass eigenstates and is entangled with the radiation. For astrophysical blackhole, the mass distribution is sharply peak about its average value with a vanishingly small standard deviation, which is consistent with our intuition of a classical object. It is then shown that as the blackhole evaporates, the evolution of the closed blackhole-radiation system is unitary. This is done by showing that the full density matrix satisfies Tr$\\rho^2=1$ at all times. Finally, it is shown that the entanglement entropy, after an initial increase, decreases and approaches zero. These show that this model of blackhole evaporation has no infromation loss.

  9. An innovation resistance factor model

    Directory of Open Access Journals (Sweden)

    Siti Salwa Mohd Ishak

    2016-09-01

    Full Text Available The process and implementation strategy of information technology in construction is generally considered through the limiting prism of theoretical contexts generated from innovation diffusion and acceptance. This research argues that more attention should be given to understanding the positive effects of resistance. The study develops a theoretical framing for the Integrated Resistance Factor Model (IRFM. The framing uses a combination of diffusion of innovation theory, technology acceptance model and social network perspective. The model is tested to identify the most significant resistance factors using Partial Least Square (PLS technique. All constructs proposed in the model are found to be significant, valid and consistent with the theoretical framework. IRFM is shown to be an effective and appropriate model of user resistance factors. The most critical factors to influence technology resistance in the online project information management system (OPIMS context are: support from leaders and peers, complexity of the technology, compatibility with key work practices; and pre-trial of the technology before it is actually deployed. The study provides a new model for further research in technology innovation specific to the construction industry.

  10. Rolling Resistance Measurement and Model Development

    DEFF Research Database (Denmark)

    Andersen, Lasse Grinderslev; Larsen, Jesper; Fraser, Elsje Sophia;

    2015-01-01

    There is an increased focus worldwide on understanding and modeling rolling resistance because reducing the rolling resistance by just a few percent will lead to substantial energy savings. This paper reviews the state of the art of rolling resistance research, focusing on measuring techniques, s......, surface and texture modeling, contact models, tire models, and macro-modeling of rolling resistance...

  11. Relationships between changes in leptin and insulin resistance levels in obese individuals following weight loss

    Directory of Open Access Journals (Sweden)

    Tsu-Nai Wang

    2013-08-01

    Full Text Available Obesity can augment insulin resistance (IR, leading to increased risk of diabetes and heart disease. Leptin, ghrelin, and various fatty acids present in the cell membrane may modulate IR. In this study, we aimed to investigate the impact of weight loss on IR, serum leptin/ghrelin levels, and erythrocyte fatty acids, and studied the associations between changes in these variables. A total of 35 obese (body mass index ≥ 27 adults participated in a weight loss program for 3 months. IR was assessed using homeostasis model assessment for insulin resistance (HOMA-IR. The obese participants had a mean weight loss of 5.6 ± 3.8 kg followed by a 16.7% and 23.3% reduction in HOMA-IR and leptin (p  0.05 levels. After adjusting for age, gender, changes in ghrelin, and body fat, we found a significant correlation between decreases in leptin and less risk of no improvement in HOMA-IR levels [odds ratio (OR = 0.69, p = 0.039]. In conclusion, a moderate weight reduction in obese participants over a short period significantly improved IR. This weight reduction concomitantly decreased serum leptin, increased ghrelin, and elevated some erythrocyte unsaturates. Only leptin correlated independently with IR improvement upon multivariable logistic regression analysis, which indicates that leptin may play a role in the modulation of IR following weight loss.

  12. Modeling the Marginal Value of Rainforest Losses

    OpenAIRE

    Strand, Jon

    2015-01-01

    A rainforest can be modeled as a dynamic asset subject to various risks, including risk of fire. Any small part of the forest can be in one of two states: either untouched by forest fire, or already damaged by fire, in which case there is both a local forest loss and increased dryness over a broader area. In this paper, two Bellman equations are constructed, one for unharmed forest and a s...

  13. Linguistic Model for Engine Power Loss

    Science.gov (United States)

    2011-11-27

    model, engine power loss, intelligent diagnostics 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Public Release 18. NUMBER OF PAGES...module via a wireless interface that is compliant with the IEEE 802.15 protocol. The wireless personal area network is implemented using the ZigBee ... secure short range wireless communications link, or via a wired Ethernet port to a mobile device (e.g., another laptop computer authorized for CBM

  14. Role of Loss of Equilibrium and Magnetic Reconnection in Coronal Eruptions: Resistive and Hall MHD simulations

    Science.gov (United States)

    Yang, H.; Bhattacharjee, A.; Forbes, T. G.

    2008-12-01

    It has long been suggested that eruptive phenomena such as coronal mass ejections, prominence eruptions, and large flares might be caused by a loss of equilibrium in a coronal flux rope (Van Tend and Kuperus, 1978). Forbes et al. (1994) developed an analytical two-dimensional model in which eruptions occur due to a catastrophic loss of equilibrium and relaxation to a lower-energy state containing a thin current sheet. Magnetic reconnection then intervenes dynamically, leading to the release of magnetic energy and expulsion of a plasmoid. We have carried out high-Lundquist-number simulations to test the loss-of equilibrium mechanism, and demonstrated that it does indeed occur in the quasi-ideal limit. We have studied the subsequent dynamical evolution of the system in resistive and Hall MHD models for single as well as multiple arcades. The typical parallel electric fields are super-Dreicer, which makes it necessary to include collisionless effects via a generalized Ohm's law. It is shown that the nature of the local dissipation mechanism has a significant effect on the global geometry and dynamics of the magnetic configuration. The presence of Hall currents is shown to alter the length of the current sheet and the jets emerging from the reconnection site, directed towards the chromosphere. Furthermore, Hall MHD effects break certain symmetries of resistive MHD dynamics, and we explore their observational consequences.

  15. Generalized effective medium resistivity model for low resistivity reservoir

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    With the advancement in oil exploration,producible oil and gas are being found in low resistivity reservoirs,which may otherwise be erroneously thought as water zones from their resistivity.However,the evaluation of low resistivity reservoirs remains difficult from log interpretation.Since low resistivity in hydrocarbon bearing sands can be caused by dispersed clay,laminated shale,conductive matrix grains,microscopic capillary pores and high saline water,a new resistivity model is required for more accurate hydrocarbon saturation prediction for low resistivity formations.Herein,a generalized effective medium resistivity model has been proposed for low resistivity reservoirs,based on experimental measurements on artificial low resistivity shaly sand samples,symmetrical anisotropic effective medium theory for resistivity interpretations,and geneses and conductance mechanisms of low resistivity reservoirs.By analyzing effects of some factors on the proposed model,we show theoretically the model can describe conductance mechanisms of low resistivity reservoirs with five geneses.Also,shale distribution largely affects water saturation predicted by the model.Resistivity index decreases as fraction and conductivity of laminated shale,or fraction of dispersed clay,or conductivity of rock matrix grains increases.Resistivity index decreases as matrix percolation exponent,or percolation rate of capillary bound water increases,and as percolation exponent of capillary bound water,or matrix percolation rate,or free water percolation rate decreases.Rock sample data from low resistivity reservoirs with different geneses and interpretation results for log data show that the proposed model can be applied in low resistivity reservoirs containing high salinity water,dispersed clay,microscopic capillary pores,laminated shale and conductive matrix grains,and thus is considered as a generalized resistivity model for low resistivity reservoir evaluation.

  16. Generalized effective medium resistivity model for low resistivity reservoir

    Institute of Scientific and Technical Information of China (English)

    SONG YanJie; TANG XiaoMin

    2008-01-01

    With the advancement in oil exploration, producible oil and gas are being found in low resistivity reservoirs, which may otherwise be erroneously thought as water zones from their resistivity. However,the evaluation of low resistivity reservoirs remains difficult from log interpretation. Since low resistivity in hydrocarbon bearing sands can be caused by dispersed clay, laminated shale, conductive matrix grains, microscopic capillary pores and high saline water, a new resistivity model is required for more accurate hydrocarbon saturation prediction for low resistivity formations. Herein, a generalized effective medium resistivity model has been proposed for low resistivity reservoirs, based on experimental measurements on artificial low resistivity shaly sand samples, symmetrical anisotropic effective medium theory for resistivity interpretations, and geneses and conductance mechanisms of low resistivity reservoirs. By analyzing effects of some factors on the proposed model, we show theoretically the model can describe conductance mechanisms of low resistivity reservoirs with five geneses. Also,shale distribution largely affects water saturation predicted by the model. Resistivity index decreases as fraction and conductivity of laminated shale, or fraction of dispersed clay, or conductivity of rock matrix grains increases. Resistivity index decreases as matrix percolation exponent, or percolation rate of capillary bound water increases, and as percolation exponent of capillary bound water, or matrix percolation rate, or free water percolation rate decreases. Rock sample data from low resistivity reservoirs with different geneses and interpretation results for log data show that the proposed model can be applied in low resistivity reservoirs containing high salinity water, dispersed clay, microscopic capillary pores, laminated shale and conductive matrix grains, and thus is considered as a generalized resistivity model for low resistivity reservoir evaluation.

  17. A Mass Loss Penetration Model to Investigate the Dynamic Response of a Projectile Penetrating Concrete considering Mass Abrasion

    OpenAIRE

    NianSong Zhang; Dong; Wang; Bei Peng; Yong He

    2015-01-01

    A study on the dynamic response of a projectile penetrating concrete is conducted. The evolutional process of projectile mass loss and the effect of mass loss on penetration resistance are investigated using theoretical methods. A projectile penetration model considering projectile mass loss is established in three stages, namely, cratering phase, mass loss penetration phase, and remainder rigid projectile penetration phase.

  18. Radiation Belt Electron Dynamics: Modeling Atmospheric Losses

    Science.gov (United States)

    Selesnick, R. S.

    2003-01-01

    The first year of work on this project has been completed. This report provides a summary of the progress made and the plan for the coming year. Also included with this report is a preprint of an article that was accepted for publication in Journal of Geophysical Research and describes in detail most of the results from the first year of effort. The goal for the first year was to develop a radiation belt electron model for fitting to data from the SAMPEX and Polar satellites that would provide an empirical description of the electron losses into the upper atmosphere. This was largely accomplished according to the original plan (with one exception being that, for reasons described below, the inclusion of the loss cone electrons in the model was deferred). The main concerns at the start were to accurately represent the balance between pitch angle diffusion and eastward drift that determines the dominant features of the low altitude data, and then to accurately convert the model into simulated data based on the characteristics of the particular electron detectors. Considerable effort was devoted to achieving these ends. Once the model was providing accurate results it was applied to data sets selected from appropriate periods in 1997, 1998, and 1999. For each interval of -30 to 60 days, the model parameters were calculated daily, thus providing good short and long term temporal resolution, and for a range of radial locations from L = 2.7 to 3.9. .

  19. Modeling Thermal Contact Resistance

    Science.gov (United States)

    Kittel, Peter; Sperans, Joel (Technical Monitor)

    1994-01-01

    One difficulty in using cryocoolers is making good thermal contact between the cooler and the instrument being cooled. The connection is often made through a bolted joint. The temperature drop associated with this joint has been the subject of many experimental and theoretical studies. The low temperature behavior of dry joints have shown some anomalous dependence on the surface condition of the mating parts. There is also some doubts on how well one can extrapolate from the test samples to predicting the performance of a real system. Both finite element and analytic models of a simple contact system have been developed. The model assumes (a) the contact is dry (contact limited to a small portion of the total available area and the spaces in-between the actual contact patches are perfect insulators), (b) contacts are clean (conductivity of the actual contact is the same as the bulk), (c) small temperature gradients (the bulk conductance may be assumed to be temperature independent), (d) the absolute temperature is low (thermal radiation effects are ignored), and (e) the dimensions of the nominal contact area are small compared to the thickness of the bulk material (the contact effects are localized near the contact). The models show that in the limit of actual contact area much less than the nominal area (a much less than A), that the excess temperature drop due to a single point of contact scales as a(exp -1/2). This disturbance only extends a distance approx. A(exp 1/2) into the bulk material. A group of identical contacts will result in an excess temperature drop that scales as n(exp -1/2), where n is the number of contacts and n dot a is constant. This implies that flat rough surfaces will have a lower excess temperature drop than flat polished surfaces.

  20. Serum HER-2 concentration is associated with insulin resistance and decreases after weight loss

    Directory of Open Access Journals (Sweden)

    Moreno-Navarrete José

    2010-02-01

    Full Text Available Abstract Background HER2/neu is a member of the epidermal growth factor receptor family easily detectable in the serum of cancer patients. We aimed to evaluate circulating HER-2 concentrations in association with insulin resistance in healthy and obese subjects. Methods Insulin sensitivity (minimal model and serum HER-2 concentrations were evaluated in a cross sectional study in men (cohort 1, n = 167 and longitudinally after weight loss in obese subjects (cohort 2, n = 30. Results Serum HER-2 concentrations were positively associated with BMI and waist circumference (both r = 0.18, p = 0.02, post-load glucose (r = 0.28, p = 0.001 and fasting triglycerides (r = 0.26, p = 0.001; and negatively associated with insulin sensitivity (r = -0.29, p = 0.002, n = 109. Subjects with type 2 diabetes showed significantly increased soluble serum HER-2 concentrations. In different multivariate regression models, fasting triglycerides emerged as the factor that independently contributed to 10-11% of serum HER-2 variance. Serum HER-2 concentrations correlated significantly with fasting triglycerides and insulin sensitivity index in subjects from cohort 2. Weight loss led to a significant decrease of serum HER-2 concentrations. The change in serum HER-2 concentrations were significantly associated with the change in percent body fat and fasting triglycerides in young (below the median age of the cohort subjects. Conclusions Serum HER-2 concentrations might be implicated in the pathophysiology of insulin resistance and associated comorbidities.

  1. Cefotaxime resistant Escherichia coli collected from a healthy volunteer; characterisation and the effect of plasmid loss.

    Directory of Open Access Journals (Sweden)

    Miranda Kirchner

    Full Text Available In this study 6 CTX-M positive E. coli isolates collected during a clinical study examining the effect of antibiotic use in a human trial were analysed. The aim of the study was to analyse these isolates and assess the effect of full or partial loss of plasmid genes on bacterial fitness and pathogenicity. A DNA array was utilised to assess resistance and virulence gene carriage. Plasmids were characterised by PCR-based replicon typing and addiction system multiplex PCR. A phenotypic array and insect virulence model were utilised to assess the effect of plasmid-loss in E. coli of a large multi-resistance plasmid. All six E. coli carrying bla CTX-M-14 were detected from a single participant and were identical by pulse field gel electrophoresis and MLST. Plasmid profiling and arrays indicated absence of a large multi-drug resistance (MDR F-replicon plasmid carrying blaTEM, aadA4, strA, strB, dfrA17/19, sul1, and tetB from one isolate. Although this isolate partially retained the plasmid it showed altered fitness characteristics e.g. inability to respire in presence of antiseptics, similar to a plasmid-cured strain. However, unlike the plasmid-cured or plasmid harbouring strains, the survival rate for Galleria mellonella infected by the former strain was approximately 5-times lower, indicating other possible changes accompanying partial plasmid loss. In conclusion, our results demonstrated that an apparently healthy individual can harbour bla CTX-M-14 E. coli strains. In one such strain, isolated from the same individual, partial absence of a large MDR plasmid resulted in altered fitness and virulence characteristics, which may have implications in the ability of this strain to infect and any subsequent treatment.

  2. Cefotaxime resistant Escherichia coli collected from a healthy volunteer; characterisation and the effect of plasmid loss.

    Science.gov (United States)

    Kirchner, Miranda; Abuoun, Manal; Mafura, Muriel; Bagnall, Mary; Hunt, Theresa; Thomas, Christopher; Weile, Jan; Anjum, Muna F

    2013-01-01

    In this study 6 CTX-M positive E. coli isolates collected during a clinical study examining the effect of antibiotic use in a human trial were analysed. The aim of the study was to analyse these isolates and assess the effect of full or partial loss of plasmid genes on bacterial fitness and pathogenicity. A DNA array was utilised to assess resistance and virulence gene carriage. Plasmids were characterised by PCR-based replicon typing and addiction system multiplex PCR. A phenotypic array and insect virulence model were utilised to assess the effect of plasmid-loss in E. coli of a large multi-resistance plasmid. All six E. coli carrying bla CTX-M-14 were detected from a single participant and were identical by pulse field gel electrophoresis and MLST. Plasmid profiling and arrays indicated absence of a large multi-drug resistance (MDR) F-replicon plasmid carrying blaTEM, aadA4, strA, strB, dfrA17/19, sul1, and tetB from one isolate. Although this isolate partially retained the plasmid it showed altered fitness characteristics e.g. inability to respire in presence of antiseptics, similar to a plasmid-cured strain. However, unlike the plasmid-cured or plasmid harbouring strains, the survival rate for Galleria mellonella infected by the former strain was approximately 5-times lower, indicating other possible changes accompanying partial plasmid loss. In conclusion, our results demonstrated that an apparently healthy individual can harbour bla CTX-M-14 E. coli strains. In one such strain, isolated from the same individual, partial absence of a large MDR plasmid resulted in altered fitness and virulence characteristics, which may have implications in the ability of this strain to infect and any subsequent treatment.

  3. Resistance to exercise-induced weight loss: compensatory behavioral adaptations.

    Science.gov (United States)

    Melanson, Edward L; Keadle, Sarah Kozey; Donnelly, Joseph E; Braun, Barry; King, Neil A

    2013-08-01

    In many interventions that are based on an exercise program intended to induce weight loss, the mean weight loss observed is modest and sometimes far less than what the individual expected. The individual responses are also widely variable, with some individuals losing a substantial amount of weight, others maintaining weight, and a few actually gaining weight. The media have focused on the subpopulation that loses little weight, contributing to a public perception that exercise has limited utility to cause weight loss. The purpose of the symposium was to present recent, novel data that help explain how compensatory behaviors contribute to a wide discrepancy in exercise-induced weight loss. The presentations provide evidence that some individuals adopt compensatory behaviors, that is, increased energy intake and/or reduced activity, that offset the exercise energy expenditure and limit weight loss. The challenge for both scientists and clinicians is to develop effective tools to identify which individuals are susceptible to such behaviors and to develop strategies to minimize their effect.

  4. Loss of the histone methyltransferase EZH2 induces resistance to multiple drugs in acute myeloid leukemia

    DEFF Research Database (Denmark)

    Göllner, Stefanie; Oellerich, Thomas; Agrawal-Singh, Shuchi

    2017-01-01

    In acute myeloid leukemia (AML), therapy resistance frequently occurs, leading to high mortality among patients. However, the mechanisms that render leukemic cells drug resistant remain largely undefined. Here, we identified loss of the histone methyltransferase EZH2 and subsequent reduction of h...

  5. fairCASH based on Loss resistant Teleportation

    OpenAIRE

    Kreft, Heinz

    2010-01-01

    This work contributes technical to the field of fair exchange protocols by proposing a new way to move safeguarded secrets between cryptographically secure endpoints excluding the possibility of duplication. After a brief introduction and presentation of an overview of the subject matter, the problem areas of creating a way to teleport secrets with the help of tamper-resistant hardware are defined. Objects like the CASTOR (a HSM element), eCoins (the secrets) and a copy-less transportation (t...

  6. Uncertainty analysis for a field-scale P loss model

    Science.gov (United States)

    Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that model predictions are inherently uncertain, few studies have addressed prediction uncertainties using P loss models. In this study we assessed the effect of model input error on predic...

  7. Acquired resistance to dasatinib in lung cancer cell lines conferred by DDR2 gatekeeper mutation and NF1 loss.

    Science.gov (United States)

    Beauchamp, Ellen M; Woods, Brittany A; Dulak, Austin M; Tan, Li; Xu, Chunxiao; Gray, Nathanael S; Bass, Adam J; Wong, Kwok-kin; Meyerson, Matthew; Hammerman, Peter S

    2014-02-01

    The treatment of non-small cell lung cancer has evolved dramatically over the past decade with the adoption of widespread use of effective targeted therapies in patients with distinct molecular alterations. In lung squamous cell carcinoma (lung SqCC), recent studies have suggested that DDR2 mutations are a biomarker for therapeutic response to dasatinib and clinical trials are underway testing this hypothesis. Although targeted therapeutics are typically quite effective as initial therapy for patients with lung cancer, nearly all patients develop resistance with long-term exposure to targeted drugs. Here, we use DDR2-dependent lung cancer cell lines to model acquired resistance to dasatinib therapy. We perform targeted exome sequencing to identify two distinct mechanisms of acquired resistance: acquisition of the T654I gatekeeper mutation in DDR2 and loss of NF1. We show that NF1 loss activates a bypass pathway, which confers ERK dependency downstream of RAS activation. These results indicate that acquired resistance to dasatinib can occur via both second-site mutations in DDR2 and by activation of bypass pathways. These data may help to anticipate mechanisms of resistance that may be identified in upcoming clinical trials of anti-DDR2 therapy in lung cancer and suggest strategies to overcome resistance.

  8. Coupling model for calculating prestress loss caused by relaxation loss, shrinkage, and creep of concrete

    Institute of Scientific and Technical Information of China (English)

    曹国辉; 胡佳星; 张锴

    2016-01-01

    The calculation model for the relaxation loss of concrete mentioned in the Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts(JTG D62—2004) wasmodified according to experimental data. Time-varying relaxation loss was considered in the new model. Moreover, prestressed reinforcement with varying lengths (caused by the shrinkage and creep of concrete) might influence the final values and the time-varying function of the forecast relaxation loss. Hence, the effects of concrete shrinkage and creep were considered when calculating prestress loss, which reflected the coupling relation between these effects and relaxation loss in concrete. Hence, the forecast relaxation loss of prestressed reinforcement under the effects of different initial stress levels at any time point can be calculated using the modified model. To simplify the calculation, the integral expression of the model can be changed into an algebraic equation. The accuracy of the result is related to the division of the periods within the ending time of deriving the final value of the relaxation loss of prestressed reinforcement. When the time division is reasonable, result accuracy is high. The modified model works excellently according to the comparison of the test results. The calculation result of the modified model mainly reflects the prestress loss values of prestressed reinforcement at each time point, which confirms that adopting the finding in practical applications is reasonable.

  9. Effect of molecular structure and slump loss resistance of polycarboxylate superplasticizers on self-compacting concrete

    Institute of Scientific and Technical Information of China (English)

    LAN Zi-dong

    2016-01-01

    A new kind of polycarboxylate superplasticizer with high slump loss resistance was obtained by designing scheduled molecular structure. The number average molecular mass of the polymer was characterized by thegel permeation chromatography measurements. And chemical structure of the polymer was observed by the Fouriertransform infrared spectroscopy(FT-IR). The results showthat the good workablemaintaining ofself-compacting concretecould be achieved through direct adjustmentof number average molecular mass and different unsaturated monomer in synthetic process. The FT-IR analysis illustrated that the high slump loss resistance of polycarboxylate superplasticizers with ester and carboxyl group and expectations of molecular structure were designed.

  10. Nonlinear Resistivity for Magnetohydrodynamical Models

    CERN Document Server

    Lingam, Manasvi; Pfefferlé, David; Comisso, Luca; Bhattacharjee, Amitava

    2016-01-01

    A nonlinear current-dependent resistivity that accurately accounts for the collisional electron-ion momentum transfer rate is derived. It is shown that the Spitzer resistivity overestimates the resistivity in certain observationally relevant regimes. The nonlinear resistivity computed herein is a strictly decreasing function of the current, in contrast to some notable previous proposals. The relative importance of the new expression with respect to the well-established electron inertia and Hall terms is also examined. The subtle implications of this current-dependent resistivity are discussed in the context of plasma systems and phenomena such as magnetic reconnection.

  11. Torque model of hydro turbine with inner energy loss characteristics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper presents the result and analysis of the composition of energy loss occurring in the hydro turbine. Two new types of energy losses,namely the hydraulic loss in the flow channel and the impact loss,are defined. All losses within the hydro turbine are divided into four types and the loss coefficients are defined accordingly. Expressions or characteristic descriptions of these losses as well as the calibration method of the loss coefficients are presented. Furthermore,the torque model of the hydro turbine where the inner energy loss takes place is established. The developed model has been used to calculate the power loss due to the mechanical friction generated by the units’ rotation to solve the difficulty of measurements of the mechanical friction loss in the hydro turbine. The definition of the impact loss explains the phenomenon that the loss of no-load is greater than that of the rated operation. A set of conversion coefficients are defined using the characteristic parameters at the rated operation,which are used to transform the parameters in the torque model into those that are easily measured. Therefore,the expression of the hydro turbine power is converted into a function that has the main servomotor displacement as its single variable. This makes the proposed model be convenient to use. Finally,the proposed model and methods are calibrated and verified using the measured data of a hydropower plant. Good agreement between the modeled results and the measurements indicates that the proposed model can represent the inner energy loss characteristics of the hydro turbine.

  12. Modeling of secondary radiation damage in LIGA PMMA resist exposure

    Science.gov (United States)

    Ting, Aili

    2003-01-01

    Secondary radiation during LIGA PMMA resist exposure adversely affects feature definition, sidewall taper and overall sidewall offset. Additionally, it can degrade the resist adjacent to the substrate, leading to the loss of free-standing features through undercutting during resist development or through mechanical failure of the degraded material. The source of this radiation includes photoelectrons, Auger electrons, fluorescence photons, etc. Sandia"s Integrated Tiger Series (ITS), a coupled electron/photon Monte Carlo transport code, was used to compute dose profiles within 1 to 2 microns of the absorber edge and near the interface of the resist with a metallized substrate. The difficulty of sub-micron resolution requirement was overcome by solving a few local problems having carefully designed micron-scale geometries. The results indicate a 2-μm dose transition region near the absorber edge resulting from PMMA"s photoelectrons. This region leads to sidewall offset and to tapered sidewalls following resist development. The results also show a dose boundary layer of around 1 μm near the substrate interface due to electrons emitted from the substrate metallization layer. The maximum dose at the resist bottom under the absorber can be very high and can lead to feature loss during development. This model was also used to investigate those resist doses resulting from multi-layer substrate.

  13. Validation of a Polyimide Foam Model for Use in Transmission Loss Applications

    Science.gov (United States)

    Hong, Kwanwoo; Bolton, J. Stuart; Cano, Roberto J.; Weiser, Erik S.; Jensen, Brian J.; Silcox, Rich; Howerton, Brian M.; Maxon, John; Wang, Tongan; Lorenzi, Tyler

    2010-01-01

    The work described in this paper was focused on the use of a new polyimide foam in a double wall sound transmission loss application. Recall that polyimide foams are functionally attractive, compared to polyurethane foams, for example, owing to their fire resistance. The foam considered here was found to have a flow resistivity that was too high for conventional acoustical applications, and as a result, it was processed by partial crushing to lower the flow resistivity into an acceptable range. Procedures for measuring the flow resistivity and Young s modulus of the material have been described, as was an inverse characterization procedure for estimating the remaining Biot parameters based on standing wave tube measurements of transmission loss and absorption coefficient. The inverse characterization was performed using a finite element model implementation of the Biot poro-elastic material theory. Those parameters were then used to predict the sound transmission loss of a double panel system lined with polyimide foam, and the predictions were compared with full-scale transmission loss measurements. The agreement between the two was reasonable, especially in the high and low frequency limits; however, it was found that the SEA model resulted in an under-prediction of the transmission loss in the mid-frequency range. Nonetheless, it was concluded that the performance of polyimide foam could be predicted using conventional poro-elastic material models and that polyimide foam may offer an attractive alternative to other double wall linings in certain situations: e.g., when fire resistance is a key issue. Future work will concentrate on reducing the density of the foam to values similar to those used in current aircraft sidewall treatments, and developing procedures to improve the performance of the foam in transmission loss applications.

  14. A Reducing Resistance to Change Model

    Directory of Open Access Journals (Sweden)

    Daniela Braduţanu

    2015-10-01

    Full Text Available The aim of this scientific paper is to present an original reducing resistance to change model. After analyzing the existent literature, I have concluded that the resistance to change subject has gained popularity over the years, but there are not too many models that could help managers implement more smoothly an organizational change process and at the same time, reduce effectively employees’ resistance. The proposed model is very helpful for managers and change agents who are confronted with a high degree of resistance when trying to implement a new change, as well as for researches. The key contribution of this paper is that resistance is not necessarily bad and if used appropriately, it can actually represent an asset. Managers must use employees’ resistance.

  15. Loss of resistance to reinfection with Schistosoma japonicum in mice after treatment with praziquantel.

    Science.gov (United States)

    Moloney, N A; Hinchcliffe, P; Webbe, G

    1987-01-01

    Seven-week-old adult Schistosoma japonicum worms were eliminated from mice within one week of treatment with praziquantel and oviposition ceased within 2 days. The excretion of faecal eggs ceased within 2 weeks of treatment. The numbers of eggs retained in the intestine and those in the liver remained constant for up to 20 weeks after cure. Untreated, infected mice were on average 80% resistant to reinfection and mice challenged one week after treatment were equally resistant. However, reductions in the ability of mice to resist a challenge were evident as early as 2 weeks after cure (average resistance 40%) and by 5 weeks the resistance had dropped significantly (average resistance 30%) in all experiments. Mice were no longer significantly resistant to challenge 13 weeks after treatment, in 2 out of 3 experiments. It is suggested that the reduced ability of cured mice to resist reinfection is related to the resolution of the granuloma response and associated pathology rather than the loss of tissue eggs.

  16. Moisture Absorption, Mass Loss and Evaporative Resistance of Clothing in Transient Condition

    Institute of Scientific and Technical Information of China (English)

    Chuansi Gao; Ingvar Holmér

    2006-01-01

    The water vapour resistance of clothing ensembles is not as commonly determined as dry thermal insulation. The measurement techniques are more complicated and the measurement values differ among laboratories. Due to complicated moisture transfer process through clothing ensemble, the moisture absorbed and evaporated varies in transient and steady state phases depending on properties,thickness of clothing, and environmental conditions. The purpse of this study was to measure moisture gain inside hygroscopic underwear, and hydrophobic and permeable outer wear as a function of time, to investigate mass loss from "skin" as well as from the manikin, to quantify evaporative heat loss and total heat loss from the manikin,and to determine water vapour resistance of clothing.Manikin Tore was used by wearing wet "skin" to simulate sweating condition. Moisture content in the inner garment gain shows an exponential relation against time. Moisture in the outer permeable layer shows little gain. On the contrary,mass loss directly from the wet skin decreases exponentially. The mass loss from the manikin is relatively stable throughout three test phases. The evaporative heat loss is about 2/3 of the total heat loss from the sweating manikin. While measuring the evaporative resistance of clothing ensembles with hygroscopic inner garment and permeable outer garment, unlike to measure ensembles with impermeable outer layer, one hour measurement time is enough to get relatively stable results. The variation between the 1st hour and the 3rd hour is less than 5%. The length of transient period and measurement time is dependent on the permeability, thickness of clothing ensembles and environmental conditions.

  17. Loss Current Analysis of Water Tree Degradation in Polyethylene using Equivalent Circuit Model

    Science.gov (United States)

    Suzuki, Masafumi; Itoh, Atsushi; Yoshimura, Noboru

    It is well known that the degradation of XLPE cable by water tree gives rise to harmonics in the loss current. Many researches by simulation and experiment have been carried out for the purpose of the elucidation of the mechanism of the harmonics in the loss current generation. In the present study, the loss current was calculated from the equivalent circuit model composed of voltage-dependent resistance and condenser. These elements are being connected with the matrix state. As a result, we were able to obtain the good agreement between the experimental value and the calculated value by appropriately choosing the characteristics of the voltage-dependent resistance. The equivalent circuit model determined in this study can consider not only the electrical characteristic of water tree but also its shape.

  18. Water losses dynamic modelling in water distribution networks

    Science.gov (United States)

    Puleo, Valeria; Milici, Barbara

    2015-12-01

    In the last decades, one of the main concerns of the water system managers have been the minimisation of water losses, that frequently reach values of 30% or even 70% of the volume supplying the water distribution network. The economic and social costs associated with water losses in modern water supply systems are rapidly rising to unacceptably high levels. Furthermore, the problem of the water losses assumes more and more importance mainly when periods of water scarcity occur or when not sufficient water supply takes part in areas with fast growth. In the present analysis, a dynamic model was used for estimating real and apparent losses of a real case study. A specific nodal demand model reflecting the user's tank installation and a specific apparent losses module were implemented. The results from the dynamic model were compared with the modelling estimation based on a steady-state approach.

  19. Loss compensation in metamaterials through embedding of active transistor based negative differential resistance circuits.

    Science.gov (United States)

    Xu, Wangren; Padilla, Willie J; Sonkusale, Sameer

    2012-09-24

    Dielectric and ohmic losses in metamaterials are known to limit their practical use. In this paper, an all-electronic approach for loss compensation in metamaterials is presented. Each unit cell of the meta-material is embedded with a cross-coupled transistor pair based negative differential resistance circuit to cancel these losses. Design, simulation and experimental results for Split Ring Resonator (SRR) metamaterials with and without loss compensation are presented. Results indicate that the quality factor (Q) of the SRR improves by over 400% at 1.6 GHz, showing the effectiveness of the approach. The proposed technique is scalable over a broad frequency range and is limited only by the maximum operating frequency of transistors, which is reaching terahertz in today's semiconductor technologies.

  20. Opportunities of probabilistic flood loss models

    Science.gov (United States)

    Schröter, Kai; Kreibich, Heidi; Lüdtke, Stefan; Vogel, Kristin; Merz, Bruno

    2016-04-01

    Oftentimes, traditional uni-variate damage models as for instance depth-damage curves fail to reproduce the variability of observed flood damage. However, reliable flood damage models are a prerequisite for the practical usefulness of the model results. Innovative multi-variate probabilistic modelling approaches are promising to capture and quantify the uncertainty involved and thus to improve the basis for decision making. In this study we compare the predictive capability of two probabilistic modelling approaches, namely Bagging Decision Trees and Bayesian Networks and traditional stage damage functions. For model evaluation we use empirical damage data which are available from computer aided telephone interviews that were respectively compiled after the floods in 2002, 2005, 2006 and 2013 in the Elbe and Danube catchments in Germany. We carry out a split sample test by sub-setting the damage records. One sub-set is used to derive the models and the remaining records are used to evaluate the predictive performance of the model. Further we stratify the sample according to catchments which allows studying model performance in a spatial transfer context. Flood damage estimation is carried out on the scale of the individual buildings in terms of relative damage. The predictive performance of the models is assessed in terms of systematic deviations (mean bias), precision (mean absolute error) as well as in terms of sharpness of the predictions the reliability which is represented by the proportion of the number of observations that fall within the 95-quantile and 5-quantile predictive interval. The comparison of the uni-variable Stage damage function and the multivariable model approach emphasises the importance to quantify predictive uncertainty. With each explanatory variable, the multi-variable model reveals an additional source of uncertainty. However, the predictive performance in terms of precision (mbe), accuracy (mae) and reliability (HR) is clearly improved

  1. Neuron Loss in Transgenic Mouse Models of Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    Oliver Wirths

    2010-01-01

    Full Text Available Since their initial generation in the mid 1990s, transgenic mouse models of Alzheimers's disease (AD have been proven to be valuable model systems which are indispensable for modern AD research. Whereas most of these models are characterized by extensive amyloid plaque pathology, inflammatory changes and often behavioral deficits, modeling of neuron loss was much less successful. The present paper discusses the current achievements of modeling neuron loss in transgenic mouse models based on APP/Aβ and Tau overexpression and provides an overview of currently available AD mouse models showing these pathological alterations.

  2. Mouse models of age-related mitochondrial neurosensory hearing loss.

    Science.gov (United States)

    Han, Chul; Someya, Shinichi

    2013-07-01

    Hearing loss is the most common sensory disorder in the elderly population. Overall, 10% of the population has a hearing loss in the US, and this age-related hearing disorder is projected to afflict more than 28 million Americans by 2030. Age-related hearing loss is associated with loss of sensory hair cells (sensory hearing loss) and/or spiral ganglion neurons (neuronal hearing loss) in the cochlea of the inner ear. Many lines of evidence indicate that oxidative stress and associated mitochondrial dysfunction play a central role in age-related neurodegenerative diseases and are a cause of age-related neurosensory hearing loss. Yet, the molecular mechanisms of how oxidative stress and/or mitochondrial dysfunction lead to hearing loss during aging remain unclear, and currently there is no treatment for this age-dependent disorder. Several mouse models of aging and age-related diseases have been linked to age-related mitochondrial neurosensory hearing loss. Evaluation of these animal models has offered basic knowledge of the mechanism underlying hearing loss associated with oxidative stress, mitochondrial dysfunction, and aging. Here we review the evidence that specific mutations in the mitochondrial DNA or nuclear DNA that affect mitochondrial function result in increased oxidative damage and associated loss of sensory hair cells and/or spiral ganglion neurons in the cochlea during aging, thereby causing hearing loss in these mouse models. Future studies comparing these models will provide further insight into fundamental knowledge about the disordered process of hearing and treatments to improve the lives of individuals with communication disorders. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. The Episure Autodetect syringe, a loss-of-resistance technique for locating the epidural space, used in pediatric patients

    NARCIS (Netherlands)

    Tielens, L.K.P.; Bruhn, J.; Vogt, M.; Geffen, G.J. van; Scheffer, G.J.

    2013-01-01

    INTRODUCTION: The Episure Autodetect syringe, a spring-loaded syringe, is a loss-of-resistance syringe with an internal compression that applies constant pressure on the plunger. As the principle of loss-of-resistance is the same for adult and for pediatric patients, the Episure Autodetect syringe s

  4. Performance modeling, loss networks, and statistical multiplexing

    CERN Document Server

    Mazumdar, Ravi

    2009-01-01

    This monograph presents a concise mathematical approach for modeling and analyzing the performance of communication networks with the aim of understanding the phenomenon of statistical multiplexing. The novelty of the monograph is the fresh approach and insights provided by a sample-path methodology for queueing models that highlights the important ideas of Palm distributions associated with traffic models and their role in performance measures. Also presented are recent ideas of large buffer, and many sources asymptotics that play an important role in understanding statistical multiplexing. I

  5. Indications of vigor loss after fire in Caribbean pine (Pinus caribaea) from electrical resistance measurements

    Science.gov (United States)

    T.E. Paysen; A.L. Koonce; E. Taylor; M.O. Rodriquez

    2006-01-01

    In May 1993, electrical resistance measurements were performed on trees in burned and unburned stands of Caribbean pine (Pinus caribaea Mor.) in north-eastern Nicaragua to determine whether tree vigor was affected by fire. An Osmose model OZ-67 Shigometer with digital readout was used to collect the sample electrical resistance data. Computer-...

  6. Modelling of Permanent Magnet Synchronous Motor Incorporating Core-loss

    Directory of Open Access Journals (Sweden)

    K. Suthamno

    2012-08-01

    Full Text Available This study proposes a dq-axis modelling of a Permanent Magnet Synchronous Motor (PMSM with copper-loss and core-loss taken into account. The proposed models can be applied to PMSM control and drive with loss minimization in simultaneous consideration. The study presents simulation results of direct drive of a PMSM under no-load and loaded conditions using the proposed models with MATLAB codes. Comparisons of the results are made among those obtained from using PSIM and SIMULINK software packages. The comparison results indicate very good agreement.

  7. Measurements of the transverse resistance and eddy current losses in a cable-in-conduit conductor

    Science.gov (United States)

    Keilin, V. E.; Kovalev, I. A.; Kruglov, S. L.; Lelekhov, S. A.; Il'in, A. A.; Naumov, A. V.; Shcherbakov, V. I.; Shutov, K. A.

    2015-11-01

    In the case of plasma current interruption in tokamaks, the conductor of toroidial field (TF) coils experiences the action of a pulsed decreasing magnetic field (PDMF) parallel to the conductor's axis. To estimate the stability of a cable-in-conduit conductor against the PDMF, a new experimental method to study different types of losses is applied. This method exploits a high sensitivity of temperature and gas pressure to input energy in a closed volume. It allows one to measure hysteresis losses with a rather high accuracy (provided that the rate of change of the PDMF is low) and a sum of hysteresis losses and eddy current losses (when the rate of change of the PDMF is high). An experimental setup to measure the transverse (circumferential) resistance and losses has been developed at the National Research Centre Kurchatov Institute. A Russianmade Nb3Sn conductor intended for the TF coils of the International Thermonuclear Experimental Reactor is subjected to a PDMF with different amplitudes and characteristic times. The electromagnetic time constant and the transverse resistivity of the conductor are experimentally determined. The maximum temperature of strands under the action of the PDMF is calculated.

  8. A simple statistical signal loss model for deep underground garage

    DEFF Research Database (Denmark)

    Nguyen, Huan Cong; Gimenez, Lucas Chavarria; Kovacs, Istvan

    2016-01-01

    In this paper we address the channel modeling aspects for a deep-indoor scenario with extreme coverage conditions in terms of signal losses, namely underground garage areas. We provide an in-depth analysis in terms of path loss (gain) and large scale signal shadowing, and a propose simple...

  9. Modeling the effects of nutria (Myocastor coypus) on wetland loss

    Science.gov (United States)

    Carter, J.; Foote, A.L.; Johnson-Randall, L. A.

    1999-01-01

    We created a model to study the process in which nutria (Myocastor coypus) feeding activities lead to erosion and loss of marsh area. This model ties together data on nutria population dynamics and feeding behavior from the literature with data from field studies on the phenology of Scirpus americanus and Spartina patens conducted in the Barataria Basin, Louisiana, USA in 1992. The complete model consists of three linked models: a model of nutria population dynamics (nutria model), a model of the annual marsh biomass cycle of Scirpus americanus and Spartina patens (biomass model), and a plant-biomass density-dependent marsh area model (area model). When all three models are linked together, they form the 'nutria-biomass-area model.' Analysis of the models indicated the following. (1) The high population densities and low survivorship rates as reported in the literature are incompatible. (2) the nutria model is sensitive to adult and juvenile survivorship and, to a lesser extent, young born per female. It is not particularly sensitive to gestation periods, impregnation rates, or time to maturity. (3) The marsh area model is not sensitive to the marsh loss equation nor to the density at which loss of marsh area begins but is sensitive to the amount of biomass destroyed per nutria. (4) Nutria numbers do not significantly decrease in the nutria-biomass-area model until the total marsh area approaches zero because marsh loss occurs only during winter when marsh biomass is at its annual low.

  10. New mass loss kinetic model for thermal decomposition of biomass

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on non-isothermal experimental results for eight Chinese biomass species, a new kinetic model,named as the "pseudo bi-component separate-stage model (PBSM)", is developed in this note to describe the mass loss behavior of biomass thermal decomposition. This model gains an advantage over the commonly used "pseudo single-component overall model (PSOM)" and "pseudo multi-component overall model (PMOM)". By means of integral analysis it is indicated that the new model is suitable to describe the mass loss kinetics of wood and leaf samples under relatively low heating rates (e.g. 10°C/rin, used in this work).``

  11. Animal models of insulin resistance: A review.

    Science.gov (United States)

    Sah, Sangeeta Pilkhwal; Singh, Barinder; Choudhary, Supriti; Kumar, Anil

    2016-12-01

    Insulin resistance can be seen as a molecular and genetic mystery, with a role in the pathophysiology of type 2 diabetes mellitus. It is a basis for a number of chronic diseases like hypertension, dyslipidemia, glucose intolerance, coronary heart disease, cerebral vascular disease along with T2DM, thus the key is to cure and prevent insulin resistance. Critical perspicacity into the etiology of insulin resistance have been gained by the use of animal models where insulin action has been modulated by various transgenic and non-transgenic models which is not possible in human studies. The following review comprises the pathophysiology involved in insulin resistance, various factors causing insulin resistance, their screening and various genetic and non-genetic animal models highlighting the pathological and metabolic characteristics of each.

  12. High vitamin E content, impact resistant UHMWPE blend without loss of wear resistance.

    Science.gov (United States)

    Oral, Ebru; Neils, Andrew; Muratoglu, Orhun K

    2015-05-01

    Antioxidant stabilization of radiation cross-linked ultrahigh molecular weight polyethylene (UHMWPE) has been introduced to improve the oxidative stability of total joint implant bearing surfaces. Blending of antioxidants (most commonly vitamin E) with UHMWPE resin powder followed by consolidation and uniform radiation cross-linking is currently available for use in both total hips and total knees. It was previously shown that the fatigue resistance of vitamin E-blended and irradiated UHMWPEs could be further improved by spatially manipulating the vitamin E concentration throughout the implant and limiting cross-linking to the surface of the implant where it is necessary for wear resistance. This was possible by designing a low concentration of vitamin E on the surface and higher concentration in the bulk of the implant because cross-linking is hindered in UHMWPE as a function of increasing vitamin E concentration. In this study, we hypothesized that such a surface cross-linked UHMWPE with low wear rate and high fatigue strength could be obtained by limiting the penetration of radiation into UHMWPE with uniform vitamin E concentration. Our hypothesis tested positive; we were able to obtain control of the surface cross-linked region by manipulating the energy of the irradiation, resulting in extremely low wear, and high impact strength. In addition, we discussed alternatives of improving the oxidation resistance of such a material by using additional vitamin E reservoirs. These results are significant because this material may allow increased use of antioxidant-stabilized, cross-linked UHMWPEs in high stress applications and in more active patients.

  13. A novel fast response and radiation-resistant scintillator detector for beam loss monitor

    Science.gov (United States)

    Ji, Y.; Tang, Z.; Li, C.; Li, X.; Shao, M.

    2017-07-01

    At high luminosity area, beam loss monitor with fast response and high radiation resistance is crucial for accelerator operation. In this article, we report the design and test results of a fast response and radiation-resistant scintillator detector as the beam loss monitor for high luminosity collider, especially at low energy region such as RFQ. The detector is consisted of a 2 cm× 2 cm× 0.5 cm LYSO crystal readout by a 6 mm × 6 mm Silicon photomultiplier. Test results from various radioactive sources show that the detector has good sensitivity to photons from tens of keV to several MeV with good linearity and energy resolution (23% for 60 keV γ-ray). For field test, two such detectors are installed outside of the vacuum chamber shell of an 800 MeV electron storage ring. The details of the test and results are introduced.

  14. Loss-improved electroacoustical modeling of small Helmholtz resonators.

    Science.gov (United States)

    Starecki, Tomasz

    2007-10-01

    Modeling of small Helmholtz resonators based on electroacoustical analogies often results in significant disagreement with measurements, as existing models do not take into account some losses that are observed in practical implementations of such acoustical circuits, e.g., in photoacoustic Helmholtz cells. The paper presents a method which introduces loss corrections to the transmission line model, resulting in substantial improvement of simulations. Values of the loss corrections obtained from comparison of frequency responses of practically implemented resonators with computer simulations are presented in tabular and graphical form. A simple analytical function that can be used for interpolation or extrapolation of the loss corrections for other dimensions of the Helmholtz resonators is also given. Verification of such a modeling method against an open two-cavity Helmholtz structure shows very good agreement between measurements and simulations.

  15. Modeling and control of copper loss in smelting slag

    Science.gov (United States)

    Tan, Pengfu

    2011-12-01

    A series of technical improvements have been implemented to address the issue of high copper losses in rotary holding furnace (RHF) slag, which were experienced at the Xstrata Copper Smelter at Mount Isa in 2007 and 2008. The copper losses in smelting slag in the RHF were more than 3% in 2006 and 2007. Thermodynamic models and viscosity models have been applied in the operation of Xstrata Copper Smelter in Australia. The theory of RHF key performance indicators has also been developed to reduce the copper losses in RHF slag. The RHF KPIs Theory has been applied in Mount Isa Copper Smelter. The copper losses in RHF slag dropped from 3.1% in 2007 to 0.76% in April 2009. The average copper loss in RHF slag in 2009 and 2010 was about 0.9%.

  16. Characterization and Mitigation of Resistive Losses in a Large Area Laser Power Converter

    Science.gov (United States)

    2014-03-27

    production such as screen printing, laser ablation , and electroplating led research away from buried contacts [15] [13]. In addition to improving heat...benefits of trenching the grid metal . After fabricating baseline LPCs, the next step will be to test them under actual laser illumination. Previous...CHARACTERIZATION AND MITIGATION OF RESISTIVE LOSSES IN A LARGE AREA LASER POWER CONVERTER THESIS Eli A. Garduño, Second Lieutenant, USAF AFIT-ENP-14

  17. Tip studies using CFD and comparison with tip loss models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Johansen, J.

    2004-01-01

    The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD......The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD...

  18. A model for calculating a.c. losses in multistage superconducting cables

    Science.gov (United States)

    Schild, T.; Ciazynski, D.

    Superconducting magnets in tokamaks for fusion experiments are subjected to fast variations in magnetic field. As the high current conductors used in these magnets are made of multistage cables, these variations induce interstrand coupling currents that create losses. These losses are usually characterized by the so-called time constant of the conductor. A model is given to calculate this time constant. Working formulas are also proposed to calculate the current induced in the different cabling stages. This model takes into account the strand characteristics and the detailed cabling pattern. Using it, a method is also given to deduce the time constant from resistive measurements. The influence of the resistive barrier (chrome plating, CuNi shell, outer bronze matrix) is pointed out. Finally, this model is applied to a conductor that is foreseen for the toroidal coils of the International Thermonuclear Experimental Reactor (ITER).

  19. Simplified Tai Chi Resistance Training versus Traditional Tai Chi in Slowing Bone Loss in Postmenopausal Women.

    Science.gov (United States)

    Wang, Huiru; Yu, Bo; Chen, Wenhua; Lu, Yingzhi; Yu, Dinghai

    2015-01-01

    Background. This study examined whether simplified Tai Chi resistance training is superior to traditional Tai Chi in slowing bone loss in postmenopausal women. Methods. This prospective trial included 119 postmenopausal women (age: 52-65 years). Subjects were randomly assigned to participate in a traditional Tai Chi program (TTC, n = 40), a simplified Tai Chi resistance training program (TCRT, n = 40), or a blank control group (routine activity, n = 39). The TTC involved traditional Yang Style Tai Chi. The primary outcome was the change of lumbar bone mass density (L2-L4) at 12 months over the baseline. Femoral neck and Ward's triangle were also measured using dual-energy X-ray absorptiometry. Results. The L2-L4 density was significantly lower at 12 months in comparison to the baseline in the blank control group. In both the TCRT and TTC groups, the L2-L4 density was comparable to the baseline. There was a trend for less bone loss in the TCRT than in the TTC group. Similar findings were observed with femoral neck and Ward's triangle. Conclusion. Simplified Tai Chi resistance training could slow bone loss in menopausal women. The results also suggested, but did not confirm, superiority to traditional Tai Chi.

  20. A Reducing Resistance to Change Model

    National Research Council Canada - National Science Library

    Daniela Braduţanu

    2015-01-01

    .... After analyzing the existent literature, I have concluded that the resistance to change subject has gained popularity over the years, but there are not too many models that could help managers...

  1. Does Regular Exercise without Weight Loss Reduce Insulin Resistance in Children and Adolescents?

    Directory of Open Access Journals (Sweden)

    YoonMyung Kim

    2013-01-01

    Full Text Available Despite considerable efforts to tackle childhood obesity, it is recognized as one of the biggest health problems globally. Childhood obesity is a leading cause of many comorbid conditions such as metabolic syndrome and insulin resistance as well as type 2 diabetes. A strong body of evidence suggests that regular exercise without calorie restriction or weight loss is associated with reduced insulin resistance as well as improved insulin sensitivity in overweight and obese adults. However, despite the well-known benefits associated with regular exercise alone, the independent role of exercise training without calorie restriction on insulin resistance is still uncertain in youth. Some studies observed that both the aerobic and resistance type of exercise training without calorie restriction resulted in meaningful changes in insulin sensitivity, suggesting that exercise alone is an effective therapeutic strategy for reducing insulin resistance in overweight and obese youth. However, only few studies are available on the optimal dose of exercise training without calorie restriction or preferred exercise modality for reducing insulin resistance, which warrants further investigations in the pediatric population.

  2. Modeling Nitrogen Losses under Rapid Infiltration Basins

    Science.gov (United States)

    Akhavan, M.; Imhoff, P. T.; Andres, A. S.; Finsterle, S.

    2011-12-01

    Rapid Infiltration Basin System (RIBS) is one of the major land treatment techniques used for wastewater treatment and reuse of recovered treated wastewater. In this system, wastewater that is treated using primary, secondary, or advanced treatment techniques is applied at high rates to shallow basins constructed in permeable deposits of soil or sand, with further treatment occurring in soil and the vadose zone before the water recharges groundwater. Because the influent wastewater is usually enriched in nitrogen (N) compounds, there is particular concern that RIBS may contaminant groundwater or nearby surface waters if not designed and operated properly. In most of the new sequenced batch reactor (SBR) wastewater treatment plants, N is found in the form of nitrate in the discharged wastewater, so denitrification (DNF) is the main reaction in N removal. The absence of molecular oxygen is one of the required conditions for DNF. During RIBS operation, application of wastewater is cyclic and typically consists of a flooding period followed by days or weeks of drying. Key operational parameters include the ratio of wetting to drying time and the hydraulic loading rate, which affect water saturation and air content in the vadose zone and as a result have an impact on DNF. Wastewater is typically distributed at a limited number of discharge points in RIBS and basins are not usually completely flooded which result in non-homogeneous distribution of wastewater and unusual surface water flow patterns. For this reason, we couple overland flow within RIBS with subsurface flow to investigate the influence of non-uniform application of wastewater on DNF. No modeling effort has been done for understanding this aspect of RIBS performance previously. TOUGH2/ iTOUGH2, a general-purpose numerical simulation program for multi-phase fluid flow in porous media, is used for modeling fluid movement. Water saturation is used as a surrogate parameter to evaluate oxygen limitations in the

  3. Loss terms in free-piston Stirling engine models

    Science.gov (United States)

    Gordon, Lloyd B.

    1992-01-01

    Various models for free piston Stirling engines are reviewed. Initial models were developed primarily for design purposes and to predict operating parameters, especially efficiency. More recently, however, such models have been used to predict engine stability. Free piston Stirling engines have no kinematic constraints and stability may not only be sensitive to the load, but also to various nonlinear loss and spring constraints. The present understanding is reviewed of various loss mechanisms for free piston Stirling engines and how they have been incorporated into engine models is discussed.

  4. Herbicide resistance modelling: past, present and future.

    Science.gov (United States)

    Renton, Michael; Busi, Roberto; Neve, Paul; Thornby, David; Vila-Aiub, Martin

    2014-09-01

    Computer simulation modelling is an essential aid in building an integrated understanding of how different factors interact to affect the evolutionary and population dynamics of herbicide resistance, and thus in helping to predict and manage how agricultural systems will be affected. In this review, we first discuss why computer simulation modelling is such an important tool and framework for dealing with herbicide resistance. We then explain what questions related to herbicide resistance have been addressed to date using simulation modelling, and discuss the modelling approaches that have been used, focusing first on the earlier, more general approaches, and then on some newer, more innovative approaches. We then consider how these approaches could be further developed in the future, by drawing on modelling techniques that are already employed in other areas, such as individual-based and spatially explicit modelling approaches, as well as the possibility of better representing genetics, competition and economics, and finally the questions and issues of importance to herbicide resistance research and management that could be addressed using these new approaches are discussed. We conclude that it is necessary to proceed with caution when increasing the complexity of models by adding new details, but, with appropriate care, more detailed models will make it possible to integrate more current knowledge in order better to understand, predict and ultimately manage the evolution of herbicide resistance.

  5. Theoretical analysis and numerical simulation of mechanical energy loss and wall resistance of steady open channel flow

    Institute of Scientific and Technical Information of China (English)

    刘士和; 薛娇

    2016-01-01

    The mechanical energy loss and the wall resistance are very important in practical engineering. These problems are investigated through theoretical analysis and numerical simulation in this paper. The results are as follows. (1) A new mechanical energy equation for the total flow is obtained, and a general formula for the calculation of the mechanical energy loss is proposed. (2) The general relationship between the wall resistance and the mechanical energy loss for the steady channel flow is obtained, the simplified form of which for the steady uniform channel flow is in consistent with the formula used in Hydraulics deduced byπ theorem and dimensional analysis. (3) The steady channel flow over a backward facing step with a small expansion ratio is numerica- lly simulated, and the mechanical energy loss, the wall resistance as well as the relationship between the wall resistance and the mechanical energy loss are calculated and analyzed.

  6. Flood loss modelling with FLF-IT: a new flood loss function for Italian residential structures

    Science.gov (United States)

    Hasanzadeh Nafari, Roozbeh; Amadio, Mattia; Ngo, Tuan; Mysiak, Jaroslav

    2017-07-01

    The damage triggered by different flood events costs the Italian economy millions of euros each year. This cost is likely to increase in the future due to climate variability and economic development. In order to avoid or reduce such significant financial losses, risk management requires tools which can provide a reliable estimate of potential flood impacts across the country. Flood loss functions are an internationally accepted method for estimating physical flood damage in urban areas. In this study, we derived a new flood loss function for Italian residential structures (FLF-IT), on the basis of empirical damage data collected from a recent flood event in the region of Emilia-Romagna. The function was developed based on a new Australian approach (FLFA), which represents the confidence limits that exist around the parameterized functional depth-damage relationship. After model calibration, the performance of the model was validated for the prediction of loss ratios and absolute damage values. It was also contrasted with an uncalibrated relative model with frequent usage in Europe. In this regard, a three-fold cross-validation procedure was carried out over the empirical sample to measure the range of uncertainty from the actual damage data. The predictive capability has also been studied for some sub-classes of water depth. The validation procedure shows that the newly derived function performs well (no bias and only 10 % mean absolute error), especially when the water depth is high. Results of these validation tests illustrate the importance of model calibration. The advantages of the FLF-IT model over other Italian models include calibration with empirical data, consideration of the epistemic uncertainty of data, and the ability to change parameters based on building practices across Italy.

  7. Quantifying nitrogen losses in oil palm plantations: models and challenges

    Science.gov (United States)

    Pardon, Lénaïc; Bessou, Cécile; Saint-Geours, Nathalie; Gabrielle, Benoît; Khasanah, Ni'matul; Caliman, Jean-Pierre; Nelson, Paul N.

    2016-09-01

    Oil palm is the most rapidly expanding tropical perennial crop. Its cultivation raises environmental concerns, notably related to the use of nitrogen (N) fertilisers and the associated pollution and greenhouse gas emissions. While numerous and diverse models exist to estimate N losses from agriculture, very few are currently available for tropical perennial crops. Moreover, there is a lack of critical analysis of their performance in the specific context of tropical perennial cropping systems. We assessed the capacity of 11 models and 29 sub-models to estimate N losses in a typical oil palm plantation over a 25-year growth cycle, through leaching and runoff, and emissions of NH3, N2, N2O, and NOx. Estimates of total N losses were very variable, ranging from 21 to 139 kg N ha-1 yr-1. On average, 31 % of the losses occurred during the first 3 years of the cycle. Nitrate leaching accounted for about 80 % of the losses. A comprehensive Morris sensitivity analysis showed the most influential variables to be soil clay content, rooting depth, and oil palm N uptake. We also compared model estimates with published field measurements. Many challenges remain in modelling processes related to the peculiarities of perennial tropical crop systems such as oil palm more accurately.

  8. Recent Developments of the Florida Public Hurricane Loss Model

    Science.gov (United States)

    Cocke, S.; Shin, D. W.; Annane, B.

    2016-12-01

    Catastrophe models are used extensively by the insurance industry to estimate losses due to natural hazards such as hurricanes and earthquakes. In the state of Florida, primary insurers for hurricane damage to residential properties are required by law to use certified catastrophe models to establish their premiums and capital reserves. The Florida Public Hurricane Loss Model (FPHLM) is one of only five certified catastrophe models in Florida, and the only non-commercial model certified. The FPHLM has been funded through the Florida Legislature and is overseen by the Florida Office of Insurance Regulation (OIR). The model was developed by a consortium of universities and private consultants primary located in Florida, but includes some partners outside of the state. The FPHLM has met Florida requirements since 2006 and has undergone continuous evolution to maintain state-of-the-art capabilities and changes in state requirements established by the Florida Commission on Hurricane Loss Projection Methodology. Recently the model has been undergoing major enhancement to incorporate damage due to flooding, which not only includes hurricane floods but floods due to all potential natural hazards. This work is being done in anticipation of future changes in the National Flood Insurance Program (NFIP) that will bring private insurers to the flood market. The model will incorporate a surge model as well as an inland flood model. We will present progress on these recent enhancements along with additional progress of the model.

  9. Greenland Ice Sheet Mass Loss from GRACE Monthly Models

    DEFF Research Database (Denmark)

    Sørensen, Louise Sandberg; Forsberg, René

    2010-01-01

    model ICE-5G and on ground measurements made in Scandinavia. We find that the PGR signal corresponds to a mass change signal of approximately -4 Gt per year. We conclude that there are large differences between these estimated mass change models. We find a total mass loss of 189, 146 and 67 Gt......The Greenland ice sheet is currently experiencing a net mass loss. There are however large discrepancies between the published qualitative mass loss estimates, based on different data sets and methods. There are even large differences between the results based on the same data sources...... these monthly global gravity models, we first calculate the gravity trend from these. When isolating the gravity trend signal, which is caused by the ice mass change, we first subtract the signal produced by the postglacial rebound (PGR) in Greenland. This is done by a simple method based on the ice history...

  10. Decision model to control water losses in distribution networks

    Directory of Open Access Journals (Sweden)

    Marcele Elisa Fontana

    2016-01-01

    Full Text Available Abstract The losses in the urban water supply networks have become a growing concern. There are several alternatives for the quantification, detection and monitoring of water losses. However, in general, water companies have budgetary and other constraints that hinder implementation. Therefore, this paper presents a model to aid the selection of a subset of preventive maintenance actions to control water losses while accounting for the water companies’ restrictions. The model combines an additive multi-attribute value analysis by applying the SMARTER method to evaluate alternatives with Integer Linear Programming (ILP. The model shows to be efficient in order to achieve a portfolio of preventive maintenance actions, particularly when the decision maker considers that, there is a compensation for attribute evaluations.

  11. A superconductor material model for hysteresis losses computation

    Energy Technology Data Exchange (ETDEWEB)

    Satiramatekul, Thitipong [Faculty of Engineering at Kamphaengsaen, Kasetsart University, Nakhon Pathom 73140 (Thailand); Bouillault, Frederic [Electrical Engineering Laboratory of Paris, Plateau de Moulon, Gif-sur-Yvette Cedex 91192 (France)

    2007-12-15

    The aim of this work was to calculate the hysteresis losses in the superconductor materials. For that, we used one macroscopic model which obtained by altering Bean's model. We propose the finite element method for the numerical modeling. Our problem consists of an infinitely long superconducting line plunged in a uniform field varying periodically in time. In this paper, we present the influence of the shape and the amplitude of the applied magnetic field to the instantaneous losses. We also present two various methods for calculating the average losses. Moreover, we could in particular obtain the quantities such as the current density or the magnetization in order to know the phenomenon of superconductivity in superconductor materials. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Isokinetic eccentric resistance training prevents loss in mechanical muscle function after running

    DEFF Research Database (Denmark)

    Oliveira, Anderson S. C.; Caputo, Fabrizio; Aagaard, Per

    2013-01-01

    The aim of the study was to verify whether 8 weeks of resistance training employing maximal isokinetic eccentric (IERT) knee extensor actions would reduce the acute force loss observed after high-intensity treadmill running exercise. It was hypothesized that specific IERT would induce protective...... effects against muscle fatigue and ultrastructural damages, preventing or reducing the loss in mechanical muscle function after running. Subjects were tested before and after IERT protocol for maximal isometric, concentric and eccentric isokinetic knee extensor strength (60° and 180° s(-1)). In a second...... session, subjects performed treadmill running (~35 min) and the previously mentioned measurements were repeated immediately after running. Subsequently, subjects were randomized to training (n = 12) consisting of 24 sessions of maximal IERT knee extensors actions at 180° s(-1), or served as controls (n...

  13. Realization of transient memory-loss with NiO-based resistive switching device

    Science.gov (United States)

    Hu, S. G.; Liu, Y.; Chen, T. P.; Liu, Z.; Yu, Q.; Deng, L. J.; Yin, Y.; Hosaka, Sumio

    2012-11-01

    A resistive switching device based on a nickel-rich nickel oxide thin film, which exhibits inherent learning and memory-loss abilities, is reported in this work. The conductance of the device gradually increases and finally saturates with the number of voltage pulses (or voltage sweepings), which is analogous to the behavior of the short-term and long-term memory in the human brain. Furthermore, the number of the voltage pulses (or sweeping cycles) required to achieve a given conductance state increases with the interval between two consecutive voltage pulses (or sweeping cycles), which is attributed to the heat diffusion in the material of the conductive filaments formed in the nickel oxide thin film. The phenomenon resembles the behavior of the human brain, i.e., forgetting starts immediately after an impression, a larger interval of the impressions leads to more memory loss, thus the memorization needs more impressions to enhance.

  14. Isokinetic eccentric resistance training prevents loss in mechanical muscle function after running.

    Science.gov (United States)

    Oliveira, Anderson Souza; Caputo, Fabrizio; Aagaard, Per; Corvino, Rogério Bulhões; Gonçalves, Mauro; Denadai, Benedito Sergio

    2013-09-01

    The aim of the study was to verify whether 8 weeks of resistance training employing maximal isokinetic eccentric (IERT) knee extensor actions would reduce the acute force loss observed after high-intensity treadmill running exercise. It was hypothesized that specific IERT would induce protective effects against muscle fatigue and ultrastructural damages, preventing or reducing the loss in mechanical muscle function after running. Subjects were tested before and after IERT protocol for maximal isometric, concentric and eccentric isokinetic knee extensor strength (60° and 180° s(-1)). In a second session, subjects performed treadmill running (~35 min) and the previously mentioned measurements were repeated immediately after running. Subsequently, subjects were randomized to training (n = 12) consisting of 24 sessions of maximal IERT knee extensors actions at 180° s(-1), or served as controls (n = 8). The effects of acute running-induced fatigue and training on isokinetic and isometric peak torque, and rate of force development (RFD) were investigated. Before IERT, running-induced eccentric torque loss at 180° s(-1) was -8 %, and RFD loss was -11 %. Longitudinal IERT led to reduced or absent acute running-induced losses in maximal IERT torque at 180° s(-1) (+2 %), being significantly reduced compared to before IERT (p 0.05). In conclusion, IERT yields a reduced strength loss after high-intensity running workouts, which may suggest a protective effect against fatigue and/or morphological damages. However, IERT may not avoid reductions in explosive muscle actions. In turn, this may allow more intense training sessions to be performed, facilitating the adaptive response to running training.

  15. Low-resistance strip sensors for beam-loss event protection

    Energy Technology Data Exchange (ETDEWEB)

    Ullán, M., E-mail: Miguel.Ullan@imb-cnm.csic.es [Centro Nacional de Microelectrónica (IMB-CNM, CSIC), Campus Universitario de Bellaterra, 08193 Barcelona (Spain); Benítez, V.; Quirion, D.; Zabala, M.; Pellegrini, G.; Lozano, M. [Centro Nacional de Microelectrónica (IMB-CNM, CSIC), Campus Universitario de Bellaterra, 08193 Barcelona (Spain); Lacasta, C.; Soldevila, U.; García, C. [Instituto de Fisica Corpuscular (IFIC, CSIC-UV), Valencia (Spain); Fadeyev, V.; Wortman, J.; DeFilippis, J.; Shumko, M.; Grillo, A.A; Sadrozinski, H.F.-W. [Santa Cruz Institute for Particle Physics (SCIPP), University of California Santa Cruz (UCSC), Santa Cruz, CA (United States)

    2014-11-21

    AC-coupled silicon strip sensors can be damaged in case of a beam loss due to the possibility of a large charge accumulation in the bulk, developing very high voltages across the coupling capacitors which can destroy them. Punch-through structures are currently used to avoid this problem helping to evacuate the accumulated charge as large voltages are developing. Nevertheless, previous experiments, performed with laser pulses, have shown that these structures can become ineffective in relatively long strips. The large value of the implant resistance can effectively isolate the “far” end of the strip from the punch-through structure leading to large voltages. We present here our developments to fabricate low-resistance strip sensors to avoid this problem. The deposition of a conducting material in contact with the implants drastically reduces the strip resistance, assuring the effectiveness of the punch-through structures. First devices have been fabricated with this new technology. Initial results with laser tests show the expected reduction in peak voltages on the low resistivity implants. Other aspects of the sensor performance, including the signal formation, are not affected by the new technology.

  16. Loss of plasmids containing cloned inserts coding for novobiocin resistance or novobiocin sensitivity in Haemophilus influenzae

    Energy Technology Data Exchange (ETDEWEB)

    Setlow, J.K.; Spikes, D.; Ledbetter, M.

    1984-06-01

    Plasmids pNov1 and pNov1s, coding for resistance and sensitivity to novobiocin, respectively, were readily lost from wild-type Haemophilus influenzae but retained in a strain lacking an inducible defective prophage. The plasmid loss could be partly or wholly eliminated by a low-copy-number mutation in the plasmid or by the presence of certain antibiotic resistance markers in the host chromosome. Release of both phage HP1c1, measured by plaque assay, and defective phage, measured by electron microscopy, was increased when the plasmids were present. The frequency of recombination between pNov1 and the chromosome, causing the plasmid to be converted to pNov1s, could under some circumstances be decreased from the normal 60 to 70% to below 10% by the presence of a kanamycin resistance marker in the chromosome. This suggested that a gene product coded for by the plasmid, the expression of which was affected by the kanamycin resistance marker, was responsible for the high recombination frequency. Evidence was obtained from in vitro experiments that the gene product was a gyrase.

  17. Sub-Rayleigh lithography using high flux loss-resistant entangled states of light

    CERN Document Server

    Rosen, Shamir; Israel, Yonatan; Ambar, Oron; Silberberg, Yaron

    2012-01-01

    Quantum lithography achieves phase super-resolution using fragile, experimentally challenging entangled states of light. We propose a scalable scheme for creating features narrower than classically achievable, with reduced use of quantum resources and consequently enhanced resistance to loss. The scheme is an implementation of interferometric lithography using a mixture of an SPDC entangled state with intense classical coherent light. We measure coincidences of up to four photons mimicking multiphoton absorption. The results show a narrowing of the interference fringes of up to 30% with respect to the best analogous classical scheme using only 10% of the non-classical light required for creating NOON states.

  18. Interleukin-18 in plasma and adipose tissue: effects of obesity, insulin resistance, and weight loss

    DEFF Research Database (Denmark)

    Bruun, Jens M; Stallknecht, Bente; Helge, Jørn W

    2007-01-01

    OBJECTIVE: Interleukin (IL)-18 is associated with obesity, insulin resistance, and cardiovascular disease. The present study compared 1) IL-18 in adipocytes versus stromal vascular (SV) cells, 2) IL-18 in plasma and adipose tissue (AT) in obese versus lean subjects, and 3) IL-18 in plasma, AT......, and skeletal muscle (SM) in obese subjects after weight loss. SUBJECTS AND METHODS: At baseline, plasma and AT IL-18 in 23 obese subjects were compared with that in 12 lean subjects. The obese subjects were submitted to a 15-week life-style intervention (hypocaloric diet and daily exercise) after which plasma...

  19. Determination of effective loss factors in reduced SEA models

    Science.gov (United States)

    Chimeno Manguán, M.; Fernández de las Heras, M. J.; Roibás Millán, E.; Simón Hidalgo, F.

    2017-01-01

    The definition of Statistical Energy Analysis (SEA) models for large complex structures is highly conditioned by the classification of the structure elements into a set of coupled subsystems and the subsequent determination of the loss factors representing both the internal damping and the coupling between subsystems. The accurate definition of the complete system can lead to excessively large models as the size and complexity increases. This fact can also rise practical issues for the experimental determination of the loss factors. This work presents a formulation of reduced SEA models for incomplete systems defined by a set of effective loss factors. This reduced SEA model provides a feasible number of subsystems for the application of the Power Injection Method (PIM). For structures of high complexity, their components accessibility can be restricted, for instance internal equipments or panels. For these cases the use of PIM to carry out an experimental SEA analysis is not possible. New methods are presented for this case in combination with the reduced SEA models. These methods allow defining some of the model loss factors that could not be obtained through PIM. The methods are validated with a numerical analysis case and they are also applied to an actual spacecraft structure with accessibility restrictions: a solar wing in folded configuration.

  20. Modeling resistance to genetic control of insects.

    Science.gov (United States)

    Alphey, Nina; Bonsall, Michael B; Alphey, Luke

    2011-02-07

    The sterile insect technique is an area-wide pest control method that reduces pest populations by releasing mass-reared sterile insects which compete for mates with wild insects. Modern molecular tools have created possibilities for improving and extending the sterile insect technique. As with any new insect control method, questions arise about potential resistance. Genetic RIDL(®)(1) (Release of Insects carrying a Dominant Lethal) technology is a proposed modification of the technique, releasing insects that are homozygous for a repressible dominant lethal genetic construct rather than being sterilized by irradiation. Hypothetical resistance to the lethal mechanism is a potential threat to RIDL strategies' effectiveness. Using population genetic and population dynamic models, we assess the circumstances under which monogenic biochemically based resistance could have a significant impact on the effectiveness of releases for population control. We assume that released insects would be homozygous susceptible to the lethal genetic construct and therefore releases would have a built-in element of resistance dilution. We find that this effect could prevent or limit the spread of resistance to RIDL constructs; the outcomes are subject to competing selective forces deriving from the fitness properties of resistance and the release ratio. Resistance that is spreading and capable of having a significant detrimental impact on population reduction is identifiable, signaling in advance a need for mitigating action.

  1. Modeling of Hysteresis Losses in Ferromagnetic Laminations under Mechanical Stress

    OpenAIRE

    Rasilo, Paavo; Singh, Deepak; Aydin, Ugur; Martin, Floran; Kouhia, Reijo; Belahcen, Anouar; Arkkio, Antero

    2015-01-01

    A novel approach for predicting magnetic hysteresis loops and losses in ferromagnetic laminations under mechanical stress is presented. The model is based on combining a Helmholtz free energy -based anhysteretic magnetoelastic constitutive law to a vector Jiles-Atherton hysteresis model. This paper focuses only on unidirectional and parallel magnetic fields and stresses, albeit the model is developed in full 3-D configuration in order to account also for strains perpendicular to the loading d...

  2. A simple statistical signal loss model for deep underground garage

    DEFF Research Database (Denmark)

    Nguyen, Huan Cong; Gimenez, Lucas Chavarria; Kovacs, Istvan

    2016-01-01

    In this paper we address the channel modeling aspects for a deep-indoor scenario with extreme coverage conditions in terms of signal losses, namely underground garage areas. We provide an in-depth analysis in terms of path loss (gain) and large scale signal shadowing, and a propose simple...... propagation model which can be used to predict cellular signal levels in similar deep-indoor scenarios. The proposed frequency-independent floor attenuation factor (FAF) is shown to be in range of 5.2 dB per meter deep....

  3. Model parameter uncertainty analysis for an annual field-scale phosphorus loss model

    Science.gov (United States)

    Phosphorous (P) loss models are important tools for developing and evaluating conservation practices aimed at reducing P losses from agricultural fields. All P loss models, however, have an inherent amount of uncertainty associated with them. In this study, we conducted an uncertainty analysis with ...

  4. Model parameter uncertainty analysis for annual field-scale P loss model

    Science.gov (United States)

    Phosphorous (P) loss models are important tools for developing and evaluating conservation practices aimed at reducing P losses from agricultural fields. All P loss models, however, have an inherent amount of uncertainty associated with them. In this study, we conducted an uncertainty analysis with ...

  5. Empirical Bayes Credibility Models for Economic Catastrophic Losses by Regions

    Directory of Open Access Journals (Sweden)

    Jindrová Pavla

    2017-01-01

    Full Text Available Catastrophic events affect various regions of the world with increasing frequency and intensity. The number of catastrophic events and the amount of economic losses is varying in different world regions. Part of these losses is covered by insurance. Catastrophe events in last years are associated with increases in premiums for some lines of business. The article focus on estimating the amount of net premiums that would be needed to cover the total or insured catastrophic losses in different world regions using Bühlmann and Bühlmann-Straub empirical credibility models based on data from Sigma Swiss Re 2010-2016. The empirical credibility models have been developed to estimate insurance premiums for short term insurance contracts using two ingredients: past data from the risk itself and collateral data from other sources considered to be relevant. In this article we deal with application of these models based on the real data about number of catastrophic events and about the total economic and insured catastrophe losses in seven regions of the world in time period 2009-2015. Estimated credible premiums by world regions provide information how much money in the monitored regions will be need to cover total and insured catastrophic losses in next year.

  6. Evaluation Model of Life Loss Due to Dam Failure

    Science.gov (United States)

    Huang, Dongjing

    2016-04-01

    Dam failure poses a serious threat to human life, however there is still lack of systematic research on life loss which due to dam failure in China. From the perspective of protecting human life, an evaluation model for life loss caused by dam failure is put forward. The model building gets three progressive steps. Twenty dam failure cases in China are preferably chosen as the basic data, considering geographical location and construction time of dams, as well as various conditions of dam failure. Then twelve impact factors of life loss are selected, including severity degree of flood, population at risk, understanding of dam failure, warning time, evacuation condition, number of damaged buildings, water temperature, reservoir storage, dam height, dam type, break time and distance from flood area to dam. And through principal component analysis, it gets four principal components consisting of the first flood character principle component, the second warning system principle component, the third human character principle component and the fourth space-time impact principle component. After multivariate nonlinear regression and ten-fold validation in combination, the evaluation model for life loss is finally established. And the result of the proposed model is closer to the true value and better in fitting effect in comparison with the results of RESCDAM method and M. Peng method. The proposed model is not only applied to evaluate life loss and its rate under various kinds of dam failure conditions in China, but also provides reliable cause analysis and prediction approach to reduce the risk of life loss.

  7. Regulator Loss Functions and Hierarchical Modeling for Safety Decision Making.

    Science.gov (United States)

    Hatfield, Laura A; Baugh, Christine M; Azzone, Vanessa; Normand, Sharon-Lise T

    2017-07-01

    Regulators must act to protect the public when evidence indicates safety problems with medical devices. This requires complex tradeoffs among risks and benefits, which conventional safety surveillance methods do not incorporate. To combine explicit regulator loss functions with statistical evidence on medical device safety signals to improve decision making. In the Hospital Cost and Utilization Project National Inpatient Sample, we select pediatric inpatient admissions and identify adverse medical device events (AMDEs). We fit hierarchical Bayesian models to the annual hospital-level AMDE rates, accounting for patient and hospital characteristics. These models produce expected AMDE rates (a safety target), against which we compare the observed rates in a test year to compute a safety signal. We specify a set of loss functions that quantify the costs and benefits of each action as a function of the safety signal. We integrate the loss functions over the posterior distribution of the safety signal to obtain the posterior (Bayes) risk; the preferred action has the smallest Bayes risk. Using simulation and an analysis of AMDE data, we compare our minimum-risk decisions to a conventional Z score approach for classifying safety signals. The 2 rules produced different actions for nearly half of hospitals (45%). In the simulation, decisions that minimize Bayes risk outperform Z score-based decisions, even when the loss functions or hierarchical models are misspecified. Our method is sensitive to the choice of loss functions; eliciting quantitative inputs to the loss functions from regulators is challenging. A decision-theoretic approach to acting on safety signals is potentially promising but requires careful specification of loss functions in consultation with subject matter experts.

  8. Nonlinear Dynamic Model of PMBLDC Motor Considering Core Losses

    DEFF Research Database (Denmark)

    Fasil, Muhammed; Mijatovic, Nenad; Jensen, Bogi Bech

    2017-01-01

    The phase variable model is used commonly when simulating a motor drive system with a three-phase permanent magnet brushless DC (PMBLDC) motor. The phase variable model neglects core losses and this affects its accuracy when modelling fractional-slot machines. The inaccuracy of phase variable model...... on the detailed analysis of the flux path and the variation of flux in different components of the machine. A prototype of fractional slot axial flux PMBLDC in-wheel motor is used to assess the proposed nonlinear dynamic model....

  9. Self-Capacitance and Resistive Losses of Saline-Water-Filled Inductors

    NARCIS (Netherlands)

    Kuipers, J.; Bruning, H.; Yntema, D.; Bakker, S.; Rijnaarts, H.H.M.

    2014-01-01

    Properties of water-filled inductors are relevant for underwater wireless energy transfer. The influence of the relative permittivity and resistivity of the core material on the impedance of an inductor can be modeled with a lumped parameter circuit. The relative permittivity of the core material ha

  10. Lattice Boltzmann model for resistive relativistic magnetohydrodynamics

    CERN Document Server

    Mohseni, F; Succi, S; Herrmann, H J

    2015-01-01

    In this paper, we develop a lattice Boltzmann model for relativistic magnetohydrodynamics (MHD). Even though the model is derived for resistive MHD, it is shown that it is numerically robust even in the high conductivity (ideal MHD) limit. In order to validate the numerical method, test simulations are carried out for both ideal and resistive limits, namely the propagation of Alfv\\'en waves in the ideal MHD and the evolution of current sheets in the resistive regime, where very good agreement is observed comparing to the analytical results. Additionally, two-dimensional magnetic reconnection driven by Kelvin-Helmholtz instability is studied and the effects of different parameters on the reconnection rate are investigated. It is shown that the density ratio has negligible effect on the magnetic reconnection rate, while an increase in shear velocity decreases the reconnection rate. Additionally, it is found that the reconnection rate is proportional to $\\sigma^{-\\frac{1}{2}}$, $\\sigma$ being the conductivity, w...

  11. Strengthening the weak link: Built Environment modelling for loss analysis

    Science.gov (United States)

    Millinship, I.

    2012-04-01

    Methods to analyse insured losses from a range of natural perils, including pricing by primary insurers and catastrophe modelling by reinsurers, typically lack sufficient exposure information. Understanding the hazard intensity in terms of spatial severity and frequency is only the first step towards quantifying the risk of a catastrophic event. For any given event we need to know: Are any structures affected? What type of buildings are they? How much damaged occurred? How much will the repairs cost? To achieve this, detailed exposure information is required to assess the likely damage and to effectively calculate the resultant loss. Modelling exposures in the Built Environment therefore plays as important a role in understanding re/insurance risk as characterising the physical hazard. Across both primary insurance books and aggregated reinsurance portfolios, the location of a property (a risk) and its monetary value is typically known. Exactly what that risk is in terms of detailed property descriptors including structure type and rebuild cost - and therefore its vulnerability to loss - is often omitted. This data deficiency is a primary source of variations between modelled losses and the actual claims value. Built Environment models are therefore required at a high resolution to describe building attributes that relate vulnerability to property damage. However, national-scale household-level datasets are often not computationally practical in catastrophe models and data must be aggregated. In order to provide more accurate risk analysis, we have developed and applied a methodology for Built Environment modelling for incorporation into a range of re/insurance applications, including operational models for different international regions and different perils and covering residential, commercial and industry exposures. Illustrated examples are presented, including exposure modelling suitable for aggregated reinsurance analysis for the UK and bespoke high resolution

  12. Loss of activating EGFR mutant gene contributes to acquired resistance to EGFR tyrosine kinase inhibitors in lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Keisuke Tabara

    Full Text Available Non-small-cell lung cancer harboring epidermal growth factor receptor (EGFR mutations attains a meaningful response to EGFR-tyrosine kinase inhibitors (TKIs. However, acquired resistance to EGFR-TKIs could affect long-term outcome in almost all patients. To identify the potential mechanisms of resistance, we established cell lines resistant to EGFR-TKIs from the human lung cancer cell lines PC9 and11-18, which harbored activating EGFR mutations. One erlotinib-resistant cell line from PC9 and two erlotinib-resistant cell lines and two gefitinib-resistant cell lines from 11-18 were independently established. Almost complete loss of mutant delE746-A750 EGFR gene was observed in the erlotinib-resistant cells isolated from PC9, and partial loss of the mutant L858R EGFR gene copy was specifically observed in the erlotinib- and gefitinib-resistant cells from 11-18. However, constitutive activation of EGFR downstream signaling, PI3K/Akt, was observed even after loss of the mutated EGFR gene in all resistant cell lines even in the presence of the drug. In the erlotinib-resistant cells from PC9, constitutive PI3K/Akt activation was effectively inhibited by lapatinib (a dual TKI of EGFR and HER2 or BIBW2992 (pan-TKI of EGFR family proteins. Furthermore, erlotinib with either HER2 or HER3 knockdown by their cognate siRNAs also inhibited PI3K/Akt activation. Transfection of activating mutant EGFR complementary DNA restored drug sensitivity in the erlotinib-resistant cell line. Our study indicates that loss of addiction to mutant EGFR resulted in gain of addiction to both HER2/HER3 and PI3K/Akt signaling to acquire EGFR-TKI resistance.

  13. Bacteriophage selection against a plasmid-encoded sex apparatus leads to the loss of antibiotic-resistance plasmids

    OpenAIRE

    Jalasvuori, Matti; Friman, Ville-Petri; Nieminen, Anne; Jaana K.H. Bamford; Buckling, Angus

    2011-01-01

    Antibiotic-resistance genes are often carried by conjugative plasmids, which spread within and between bacterial species. It has long been recognized that some viruses of bacteria (bacteriophage; phage) have evolved to infect and kill plasmid-harbouring cells. This raises a question: can phages cause the loss of plasmid-associated antibiotic resistance by selecting for plasmid-free bacteria, or can bacteria or plasmids evolve resistance to phages in other ways? Here, we show that multiple ant...

  14. Tip Studies using CFD and Comparison with Tip Loss Models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    2004-01-01

    of the averaged axial induction factor and the normal and tangential loads are compared with those of a standard blade element momentum code using 2D calibrated airfoil data for a wind speed of 9 m s(-1), where the agreement in computed power is good. Further, a comparison with a new tip loss model proposed...

  15. Current amplification models of sensorineurall and conductive hearing loss

    Directory of Open Access Journals (Sweden)

    Ostojić Sanja

    2012-01-01

    Full Text Available The main function of a hearing aid is to improve auditory and language abilities of hearing impaired users. The amplification model has to be adapted according to age, degree and type of hearing loss. The goal of this paper is to analyze the current amplification models of sensorineural and conductive hearing loss which can provide a high quality of speech perception and sounds at any degree of hearing loss. The BAHA is a surgically implantable system for treatment of conductive hearing loss that works through direct bone conduction. BAHA is used to help people with chronic ear infections, congenital external auditory canal atresia and single sided deafness who cannot benefit from conventional hearing aids. The last generation of hearing aid for sensorineural hearing loss is cochlear implant. Bimodal amplification improves binaural hearing. Hearing aids alone do not make listening easier in all situations. The things that can interfere with listening are background noises, distance from a sound and reverberation or echo. The device used most often today is the Frequency Modulated (FM system.

  16. Bacteriophage selection against a plasmid-encoded sex apparatus leads to the loss of antibiotic-resistance plasmids.

    Science.gov (United States)

    Jalasvuori, Matti; Friman, Ville-Petri; Nieminen, Anne; Bamford, Jaana K H; Buckling, Angus

    2011-12-23

    Antibiotic-resistance genes are often carried by conjugative plasmids, which spread within and between bacterial species. It has long been recognized that some viruses of bacteria (bacteriophage; phage) have evolved to infect and kill plasmid-harbouring cells. This raises a question: can phages cause the loss of plasmid-associated antibiotic resistance by selecting for plasmid-free bacteria, or can bacteria or plasmids evolve resistance to phages in other ways? Here, we show that multiple antibiotic-resistance genes containing plasmids are stably maintained in both Escherichia coli and Salmonella enterica in the absence of phages, while plasmid-dependent phage PRD1 causes a dramatic reduction in the frequency of antibiotic-resistant bacteria. The loss of antibiotic resistance in cells initially harbouring RP4 plasmid was shown to result from evolution of phage resistance where bacterial cells expelled their plasmid (and hence the suitable receptor for phages). Phages also selected for a low frequency of plasmid-containing, phage-resistant bacteria, presumably as a result of modification of the plasmid-encoded receptor. However, these double-resistant mutants had a growth cost compared with phage-resistant but antibiotic-susceptible mutants and were unable to conjugate. These results suggest that bacteriophages could play a significant role in restricting the spread of plasmid-encoded antibiotic resistance.

  17. CREDIT MANAGEMENT MODEL WITH A GIVEN LOSS RATE

    Directory of Open Access Journals (Sweden)

    Elena G. Snegova

    2013-01-01

    Full Text Available This article describes the credit limit model with a given loss rate. Applying this model, it is possible to increase the profitability of the bank’s product in the case of fast loans issued in the form of credit cards. Author offers a method for simulating of credit limit utilization functions. It is formulated and solved the problem of finding the optimal credit limit for the borrower.

  18. Programming finite element method based hysteresis loss computation software using non-linear superconductor resistivity and T - phiv formulation

    Science.gov (United States)

    Stenvall, A.; Tarhasaari, T.

    2010-07-01

    Due to the rapid development of personal computers from the beginning of the 1990s, it has become a reality to simulate current penetration, and thus hysteresis losses, in superconductors with other than very simple one-dimensional (1D) Bean model computations or Norris formulae. Even though these older approaches are still usable, they do not consider, for example, multifilamentary conductors, local critical current dependency on magnetic field or varying n-values. Currently, many numerical methods employing different formulations are available. The problem of hysteresis losses can be scrutinized via an eddy current formulation of the classical theory of electromagnetism. The difficulty of the problem lies in the non-linear resistivity of the superconducting region. The steep transition between the superconducting and the normal states often causes convergence problems for the most common finite element method based programs. The integration methods suffer from full system matrices and, thus, restrict the number of elements to a few thousands at most. The so-called T - phiv formulation and the use of edge elements, or more precisely Whitney 1-forms, within the finite element method have proved to be a very suitable method for hysteresis loss simulations of different geometries. In this paper we consider making such finite element method software from first steps, employing differential geometry and forms.

  19. Programming finite element method based hysteresis loss computation software using non-linear superconductor resistivity and T - {psi} formulation

    Energy Technology Data Exchange (ETDEWEB)

    Stenvall, A; Tarhasaari, T, E-mail: antti.stenvall@tut.f [Electromagnetics, Tampere University of Technology, PO Box 692, 33101 Tampere (Finland)

    2010-07-15

    Due to the rapid development of personal computers from the beginning of the 1990s, it has become a reality to simulate current penetration, and thus hysteresis losses, in superconductors with other than very simple one-dimensional (1D) Bean model computations or Norris formulae. Even though these older approaches are still usable, they do not consider, for example, multifilamentary conductors, local critical current dependency on magnetic field or varying n-values. Currently, many numerical methods employing different formulations are available. The problem of hysteresis losses can be scrutinized via an eddy current formulation of the classical theory of electromagnetism. The difficulty of the problem lies in the non-linear resistivity of the superconducting region. The steep transition between the superconducting and the normal states often causes convergence problems for the most common finite element method based programs. The integration methods suffer from full system matrices and, thus, restrict the number of elements to a few thousands at most. The so-called T - {psi} formulation and the use of edge elements, or more precisely Whitney 1-forms, within the finite element method have proved to be a very suitable method for hysteresis loss simulations of different geometries. In this paper we consider making such finite element method software from first steps, employing differential geometry and forms.

  20. MODELS OF INSULIN RESISTANCE AND HEART FAILURE

    Science.gov (United States)

    Velez, Mauricio; Kohli, Smita; Sabbah, Hani N.

    2013-01-01

    The incidence of heart failure (HF) and diabetes mellitus is rapidly increasing and is associated with poor prognosis. In spite of the advances in therapy, HF remains a major health problem with high morbidity and mortality. When HF and diabetes coexist, clinical outcomes are significantly worse. The relationship between these two conditions has been studied in various experimental models. However, the mechanisms for this interrelationship are complex, incompletely understood, and have become a matter of considerable clinical and research interest. There are only few animal models that manifest both HF and diabetes. However, the translation of results from these models to human disease is limited and new models are needed to expand our current understanding of this clinical interaction. In this review, we discuss mechanisms of insulin signaling and insulin resistance, the clinical association between insulin resistance and HF and its proposed pathophysiologic mechanisms. Finally, we discuss available animal models of insulin resistance and HF and propose requirements for future new models. PMID:23456447

  1. An analytical model for resistivity tools

    Energy Technology Data Exchange (ETDEWEB)

    Hovgaard, J.

    1991-04-01

    An analytical model for resistivity tools is developed. It takes into account the effect of the borehole and the actual shape of the electrodes. The model is two-dimensional, i.e. the model does not deal with eccentricity. The electrical potential around a current source satisfies Poisson`s equation. The method used here to solve Poisson`s equation is the expansion fo the potential function in terms of a complete set of functions involving one of the coordinates with coefficients which are undetermined functions of the other coordinate. Numerical examples of the use of the model are presented. The results are compared with results given in the literature. (au).

  2. Two-dimensional model of intrinsic magnetic flux losses in helical flux compression generators

    CERN Document Server

    Haurylavets, V V

    2012-01-01

    Helical Flux Compression Generators (HFCG) are used for generation of mega-amper current and high magnetic fields. We propose the two dimensional HFCG filament model based on the new description of the stator and armature contact point. The model developed enables one to quantitatively describe the intrinsic magnetic flux losses and predict the results of experiments with various types of HFCGs. We present the effective resistance calculations based on the non-linear magnetic diffusion effect describing HFCG performance under the strong conductor heating by currents.

  3. The Sound of Silence: Mouse Models for Hearing Loss

    Directory of Open Access Journals (Sweden)

    Sumantra Chatterjee

    2011-01-01

    Full Text Available Sensorineural hearing loss is one of the most common disabilities in humans. It is estimated that about 278 million people worldwide have slight to extreme hearing loss in both ears, which results in an economic loss for the country and personal loss for the individual. It is thus critical to have a deeper understanding of the causes for hearing loss to better manage and treat the affected individuals. The mouse serves as an excellent model to study and recapitulate some of these phenotypes, identify new genes which cause deafness, and to study their roles in vivo and in detail. Mutant mice have been instrumental in elucidating the function and mechanisms of the inner ear. The development and morphogenesis of the inner ear from an ectodermal layer into distinct auditory and vestibular components depends on well-coordinated gene expression and well-orchestrated signaling cascades within the otic vesicle and interactions with surrounding layers of tissues. Any disruption in these pathways can lead to hearing impairment. This review takes a look at some of the genes and their corresponding mice mutants that have shed light on the mechanism governing hearing impairment (HI in humans.

  4. The impact of rapid weight loss (4%) on leptin, adiponectin, and insulin resistance in elite adult free style wrestlers.

    Science.gov (United States)

    Talaei, Mohammad; Nazem, Farzad; Ranjbar, Kamal

    2017-04-01

    The effect of rapid weight loss program on adipocytokines is not yet clear. Therefore the aim of the present study was the effect of rapid weight loss (4%) on leptin, adiponectin, and insulin resistance in elite free style wrestlers. For this purpose, fifteen young freestyle wrestlers (weight 67.6±0.8, BMI 22.5±0.21 kg/m², body fat percent 6.12±0.18, waist to hip circumference ratio 0.82±0.08) in two weight categories (60 and 66 kg) were randomly selected. Caloric intake (mean 7 days measured by Food analyzer software) measured at 1 week before weight loss program by standard methods. Wrestlers performed a week rapid weight loss (average of 4% of body weight loss) protocol by caloric and water restriction by 60% (600-700 kcal per day), under the supervision of their coach. Anthropometric characteristics, leptin, adiponectin and insulin resistance were measured before and 12 and 36 hours after rapid weight loss program. Rapid weight loss program with 4% of weight loss had a significantly reduced impact on anthropometric factors; leptin level, insulin resistance, and increased beta cell function, while the changes of adiponectin were not significant after rapid weight loss. Findings of this study shows that rapid weight loss program significantly decreased leptin, L/A ratio and HOMA-IR, without significant changes on adiponectin levels. These changes may have harmful physiological effects on wrestlers' bodies but they can be useful to regulate of fatty acid, glucose metabolism, and insulin resistance.

  5. An antireflection transparent conductor with ultralow optical loss (<2 %) and electrical resistance (<6 Ω sq-1)

    Science.gov (United States)

    Maniyara, Rinu Abraham; Mkhitaryan, Vahagn K.; Chen, Tong Lai; Ghosh, Dhriti Sundar; Pruneri, Valerio

    2016-12-01

    Transparent conductors are essential in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and solar cells. Here we demonstrate a transparent conductor with optical loss of ~1.6%, that is, even lower than that of single-layer graphene (2.3%), and transmission higher than 98% over the visible wavelength range. This was possible by an optimized antireflection design consisting in applying Al-doped ZnO and TiO2 layers with precise thicknesses to a highly conductive Ag ultrathin film. The proposed multilayer structure also possesses a low electrical resistance (5.75 Ω sq-1), a figure of merit four times larger than that of indium tin oxide, the most widely used transparent conductor today, and, contrary to it, is mechanically flexible and room temperature deposited. To assess the application potentials, transparent shielding of radiofrequency and microwave interference signals with ~30 dB attenuation up to 18 GHz was achieved.

  6. Continuous alcoholic fermentation process: model considering loss of cell viability

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, S.C.; Paiva, T.C.B.; Visconti, A.E.S. [Departamento de Biotecnologia, Faculdade de Engenharia Quimica de Lorena, P.O. BOX 116, 12600-000, Lorena, SP (Brazil); Giudici, R. [Departamento de Engenharia Quimica, Escola Politecnica, Universidade de Sao Paulo, P.O. BOX 61548, 05424-970, Sao Paulo, SP (Brazil)

    1999-02-04

    The concept of loss of cell viability was introduced into a model previously developed for a continuous alcoholic fermentation process in a tower reactor with recycling of flocculating yeasts. The two models take into account substrate limitation and inhibition phenomena linked to ethanol and biomass. The kinetic parameters were estimated from steady-state data of several sugar concentrations in feeding stream and constant dilution rate, recycle ratio and temperature. Some parameters of the modified model (maximum specific rates) were significantly different from those estimated with the original model while others (inhibition parameters) remained practically unchanged. Both models provided similar predictions and were equally suitable for modelling of the process. (orig.) With 1 fig., 2 tabs., 11 refs.

  7. Modelling of Heat Loss in Closed Vessels during propellant Burning

    Directory of Open Access Journals (Sweden)

    U.P. KulKarni

    2000-10-01

    Full Text Available Closed vessel technique is essentially used to determine the force constant, vivacity and the burning rate of gun propellants. In fact, it is the only method to find out these three parameters experimentally. It is a well-known fact that however small the propellant burning time may be, there will be heat loss to the walls of the vessel due to conduction, convection, radiation and also due to the expansion of the vessel. This fact necessitates applying correction to the observed maximum pressure in the experiment. An analysis is presented in this paper as to how this heat loss can be modelled along with discussion about other models reported in this field.

  8. Qualitative modeling of the dynamics of detonations with losses

    KAUST Repository

    Faria, Luiz

    2015-01-01

    We consider a simplified model for the dynamics of one-dimensional detonations with generic losses. It consists of a single partial differential equation that reproduces, at a qualitative level, the essential properties of unsteady detonation waves, including pulsating and chaotic solutions. In particular, we investigate the effects of shock curvature and friction losses on detonation dynamics. To calculate steady-state solutions, a novel approach to solving the detonation eigenvalue problem is introduced that avoids the well-known numerical difficulties associated with the presence of a sonic point. By using unsteady numerical simulations of the simplified model, we also explore the nonlinear stability of steady-state or quasi-steady solutions. © 2014 The Combustion Institute.

  9. Energy current loss instability model on a computer

    Science.gov (United States)

    Edighoffer, John A.

    1995-04-01

    The computer program called Energy Stability in a Recirculating Accelerator (ESRA) Free Electron Laser (FEL) has been written to model bunches of particles in longitudinal phase space transversing a recirculating accelerator and the associated rf changes and aperture current losses. This energy-current loss instability was first seen by Los Alamos's FEL group in their energy recovery experiments. This code addresses these stability issues and determines the transport, noise, feedback and other parameters for which these FEL systems are stable or unstable. Two representative systems are modeled, one for the Novosibirisk high power FEL racetrack microtron for photochemical research, the other is the CEBAF proposed UV FEL system. Both of these systems are stable with prudent choices of parameters.

  10. Lattice Boltzmann model for resistive relativistic magnetohydrodynamics.

    Science.gov (United States)

    Mohseni, F; Mendoza, M; Succi, S; Herrmann, H J

    2015-08-01

    In this paper, we develop a lattice Boltzmann model for relativistic magnetohydrodynamics (MHD). Even though the model is derived for resistive MHD, it is shown that it is numerically robust even in the high conductivity (ideal MHD) limit. In order to validate the numerical method, test simulations are carried out for both ideal and resistive limits, namely the propagation of Alfvén waves in the ideal MHD and the evolution of current sheets in the resistive regime, where very good agreement is observed comparing to the analytical results. Additionally, two-dimensional magnetic reconnection driven by Kelvin-Helmholtz instability is studied and the effects of different parameters on the reconnection rate are investigated. It is shown that the density ratio has a negligible effect on the magnetic reconnection rate, while an increase in shear velocity decreases the reconnection rate. Additionally, it is found that the reconnection rate is proportional to σ-1/2, σ being the conductivity, which is in agreement with the scaling law of the Sweet-Parker model. Finally, the numerical model is used to study the magnetic reconnection in a stellar flare. Three-dimensional simulation suggests that the reconnection between the background and flux rope magnetic lines in a stellar flare can take place as a result of a shear velocity in the photosphere.

  11. An ABA-mimicking ligand that reduces water loss and promotes drought resistance in plants

    Institute of Scientific and Technical Information of China (English)

    Minjie Cao; Xue Liu; Yan Zhang; Xiaoqian Xue; X Edward Zhou; Karsten Melcher; Pan Gao

    2013-01-01

    Abscisic acid (ABA) is the most important hormone for plants to resist drought and other abiotic stresses.ABA binds directly to the PYR/PYL family of ABA receptors,resulting in inhibition of type 2C phosphatases (PP2C) and activation of downstream ABA signaling.It is envisioned that intervention of ABA signaling by small molecules could help plants to overcome abiotic stresses such as drought,cold and soil salinity.However,chemical instability and rapid catabolism by plant enzymes limit the practical application ofABA itseif.Here we report the identification of a small molecule ABA mimic (AM1) that acts as a potent activator of multiple members of the family of ABA receptors.In Arabidopsis,AM1 activates a gene network that is highly similar to that induced by ABA.Treatments with AM1 inhibit seed germination,prevent leaf water loss,and promote drought resistance.We solved the crystal structure of AM1 in complex with the PYL2 ABA receptor and the HAB1 PP2C,which revealed that AM1 mediates a gate-latchlock interacting network,a structural feature that is conserved in the ABA-bound receptor/PP2C complex.Together,these results demonstrate that a single small molecule ABA mimic can activate multiple ABA receptors and protect plants from water loss and drought stress.Moreover,the AM1 complex crystal structure provides a structural basis for designing the next generation of ABA-mimicking small molecules.

  12. Simulation with Ideal Switch Models Combined with Measured Loss Data Provides a Good Estimate of Power Loss

    Institute of Scientific and Technical Information of China (English)

    StigMunk-Nielsen; Lucian; N; Tutelea; Ulrik; Jager

    2007-01-01

    Ideally, converter losses should be determined without using an excessive amount of simulation time. State-of-the-art power semiconductor models provide good accuracy,unfortunately they often require a very long simulation time. This paper describes how to estimate power losses from simulation using ideal switches combined with measured power loss data. The semiconductor behavior is put into a look-up table,which replaces the advanced semiconductor models and shortens the simulation time.To extract switching and conduction losses, a converter is simulated and the semiconductor power losses are estimated. Measurement results on a laboratory converter are compared with the estimated losses and a good agreement is shown. Using the ideal switch simulation and the post processing power estimation program,a ten to twenty fold increase in simulation speed is obtained,compared to simulations using advanced models of semiconductors.

  13. Differential Bone Loss in Mouse Models of Colon Cancer Cachexia.

    Science.gov (United States)

    Bonetto, Andrea; Kays, Joshua K; Parker, Valorie A; Matthews, Ryan R; Barreto, Rafael; Puppa, Melissa J; Kang, Kyung S; Carson, James A; Guise, Theresa A; Mohammad, Khalid S; Robling, Alexander G; Couch, Marion E; Koniaris, Leonidas G; Zimmers, Teresa A

    2016-01-01

    Cachexia is a distinctive feature of colorectal cancer associated with body weight loss and progressive muscle wasting. Several mechanisms responsible for muscle and fat wasting have been identified, however it is not known whether the physiologic and molecular crosstalk between muscle and bone tissue may also contribute to the cachectic phenotype in cancer patients. The purpose of this study was to clarify whether tumor growth associates with bone loss using several experimental models of colorectal cancer cachexia, namely C26, HT-29, and Apc(Min/+). The effects of cachexia on bone structure and strength were evaluated with dual energy X-ray absorptiometry (DXA), micro computed tomography (μCT), and three-point bending test. We found that all models showed tumor growth consistent with severe cachexia. While muscle wasting in C26 hosts was accompanied by moderate bone depletion, no loss of bone strength was observed. However, HT-29 tumor bearing mice showed bone abnormalities including significant reductions in whole-body bone mineral density (BMD), bone mineral content (BMC), femoral trabecular bone volume fraction (BV/TV), trabecular number (Tb.N), and trabecular thickness (Tb.Th), but no declines in strength. Similarly, cachexia in the Apc(Min/+) mice was associated with significant decreases in BMD, BMC, BV/TV, Tb.N, and Tb.Th as well as decreased strength. Our data suggest that colorectal cancer is associated with muscle wasting and may be accompanied by bone loss dependent upon tumor type, burden, stage and duration of the disease. It is clear that preserving muscle mass promotes survival in cancer cachexia. Future studies will determine whether strategies aimed at preventing bone loss can also improve outcomes and survival in colorectal cancer cachexia.

  14. Differential Bone Loss in Mouse Models of Colon Cancer Cachexia

    Science.gov (United States)

    Bonetto, Andrea; Kays, Joshua K.; Parker, Valorie A.; Matthews, Ryan R.; Barreto, Rafael; Puppa, Melissa J.; Kang, Kyung S.; Carson, James A.; Guise, Theresa A.; Mohammad, Khalid S.; Robling, Alexander G.; Couch, Marion E.; Koniaris, Leonidas G.; Zimmers, Teresa A.

    2017-01-01

    Cachexia is a distinctive feature of colorectal cancer associated with body weight loss and progressive muscle wasting. Several mechanisms responsible for muscle and fat wasting have been identified, however it is not known whether the physiologic and molecular crosstalk between muscle and bone tissue may also contribute to the cachectic phenotype in cancer patients. The purpose of this study was to clarify whether tumor growth associates with bone loss using several experimental models of colorectal cancer cachexia, namely C26, HT-29, and ApcMin/+. The effects of cachexia on bone structure and strength were evaluated with dual energy X-ray absorptiometry (DXA), micro computed tomography (μCT), and three-point bending test. We found that all models showed tumor growth consistent with severe cachexia. While muscle wasting in C26 hosts was accompanied by moderate bone depletion, no loss of bone strength was observed. However, HT-29 tumor bearing mice showed bone abnormalities including significant reductions in whole-body bone mineral density (BMD), bone mineral content (BMC), femoral trabecular bone volume fraction (BV/TV), trabecular number (Tb.N), and trabecular thickness (Tb.Th), but no declines in strength. Similarly, cachexia in the ApcMin/+ mice was associated with significant decreases in BMD, BMC, BV/TV, Tb.N, and Tb.Th as well as decreased strength. Our data suggest that colorectal cancer is associated with muscle wasting and may be accompanied by bone loss dependent upon tumor type, burden, stage and duration of the disease. It is clear that preserving muscle mass promotes survival in cancer cachexia. Future studies will determine whether strategies aimed at preventing bone loss can also improve outcomes and survival in colorectal cancer cachexia. PMID:28123369

  15. Synergistic impacts of habitat loss and fragmentation on model ecosystems.

    Science.gov (United States)

    Bartlett, Lewis J; Newbold, Tim; Purves, Drew W; Tittensor, Derek P; Harfoot, Michael B J

    2016-09-28

    Habitat loss and fragmentation are major threats to biodiversity, yet separating their effects is challenging. We use a multi-trophic, trait-based, and spatially explicit general ecosystem model to examine the independent and synergistic effects of these processes on ecosystem structure. We manipulated habitat by removing plant biomass in varying spatial extents, intensities, and configurations. We found that emergent synergistic interactions of loss and fragmentation are major determinants of ecosystem response, including population declines and trophic pyramid shifts. Furthermore, trait-mediated interactions, such as a disproportionate sensitivity of large-sized organisms to fragmentation, produce significant effects in shaping responses. We also show that top-down regulation mitigates the effects of land use on plant biomass loss, suggesting that models lacking these interactions-including most carbon stock models-may not adequately capture land-use change impacts. Our results have important implications for understanding ecosystem responses to environmental change, and assessing the impacts of habitat fragmentation. © 2016 The Authors.

  16. Chemically amplified resist modeling in OPC

    Science.gov (United States)

    Zheng, Xin; Huang, Jason; Kuo, Fred; Kazarian, Aram; Chin, Fook; Fan, Yongfa

    2009-03-01

    The mechanism of chemically amplified resist plays a critical role in the modeling of the latent image. To achieve a practical model which can fit into the time frame of OPC, some simplifications and assumptions have to be made. We introduced regression kernels that take into account best exposure focus difference between isotropic pitch, dense, and line end features for the evaluation of image intensity. It compares the image intensity (signal) over small changes above and/or below the regressed "nominal" image position, which in principle corresponds to evaluating the intensity signal at various depths of a fixed resist profile thus can also be regressed for optimization during model development. Our calibration has shown that the model brought a great improvement in prediction for difficult structures such as dense features at or near the optical resolution limit and 2-dimensional features, which are the limiter of the overall model fitting accuracy for 45nm node and below. By replacing other existing techniques, total number of output kernels used for OPC operation is actually reduced with improvement of model accuracy. This model is proven to be a very effective yet accurate addition to the current OPC technology.

  17. Loss of prion protein is associated with the development of insulin resistance and obesity.

    Science.gov (United States)

    de Brito, Giovanna; Lupinacci, Fernanda C; Beraldo, Flávio H; Santos, Tiago G; Roffé, Martín; Lopes, Marilene H; de Lima, Vladmir C; Martins, Vilma R; Hajj, Glaucia N

    2017-08-17

    Prion protein (PrP(C)) was initially described due to its involvement in transmissible spongiform encephalopathies. It was subsequently demonstrated to be a cell surface molecule involved in many physiological processes, such as vesicle trafficking. Here, we investigated the roles of PrP(C) in the response to insulin and obesity development. Two independent PrP(C) knockout (KO) and one PrP(C) overexpressing (TG20) mouse models were fed high-fat diets, and the development of insulin resistance and obesity was monitored. PrP(C) KO mice fed high-fat diets presented all of the symptoms associated with the development of insulin resistance: hyperglycemia, hyperinsulinemia, and obesity. Conversely, TG20 animals fed high-fat diets showed reduced weight and insulin resistance. Accordingly, the expression of peroxisome proliferator-activated receptor gamma (PPARγ) was reduced in PrP(C) KO mice and increased in TG20 animals. PrP(C) KO cells also presented reduced glucose uptake upon insulin stimulation, due to reduced translocation of the glucose transporter Glut4. Thus, our results suggest that PrP(C) reflects susceptibility to the development of insulin resistance and metabolic syndrome. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  18. Loss of hif-1 promotes resistance to the exogenous mitochondrial stressor ethidium bromide in Caenorhabditis elegans.

    Science.gov (United States)

    Kamal, Muntasir; D'Amora, Dayana R; Kubiseski, Terrance J

    2016-09-13

    Mitochondrial dysfunction is one of the leading causes of neurological disorders in humans. Mitochondrial perturbations lead to adaptive mechanisms that include HIF-1 stabilization, though the consequences of increased levels of HIF-1 following mitochondrial stress remain poorly understood. Using Caenorhabditis elegans, we show that a hif-1 loss-of-function mutation confers resistance towards the mitochondrial toxin ethidium bromide (EtBr) and suppresses EtBr-induced production of ROS. In mammals, the PD-related gene DJ-1 is known to act as a redox sensor to confer protection against antioxidants and mitochondrial inhibitors. A deletion mutant of the C. elegans homolog djr-1.1 also showed increased resistance to EtBr. Furthermore, our data implicates p38 MAP kinase as an indispensable factor for survival against mitochondrial stress in both hif-1 and djr-1.1 mutants. We propose that EtBr-induced HIF-1 activates pathways that are antagonistic in conferring protection against EtBr toxicity and that blocking HIF-1 activity may promote survival in cells with compromised mitochondrial function.

  19. Coagulation inhibitors and activated protein C resistance in recurrent pregnancy losses in Indian women

    Directory of Open Access Journals (Sweden)

    P Lalita Jyotsna

    2011-01-01

    Full Text Available Background: Thrombophilias, both acquired and inherited, have been investigated in the etiopathogenesis of unexplained recurrent pregnancy loss. Aim: To study coagulation inhibitors and activated protein C resistance (APCR in recurrent pregnancy losses (RPL occurring in second and third trimesters. Materials and Methods: A total of 30 pregnant women (group A with two or more recurrent unexplained fetal loses were evaluated for APCR, protein C deficiency, protein S deficiency, antithrombin deficiency, and antiphospholipid antibodies (APLA. Thirty age-matched controls were taken (group B comprising of pregnant women with at least one live issue. Statistical Analysis: Comparisons between two group frequencies and group means were made using Chi square test and Student′s t test, respectively. Results: Protein C and protein S levels were reduced in group A compared with group B and the difference was statistically significant (P=0.005 and P=0.032, respectively. The mean value of antithrombin was slightly reduced in group A compared with group B. APCR was observed in 16.6% cases and 3.3% controls. However, the difference was not statistically significant. APLA was observed in 20% cases and none of the controls. Of these, lupus anticoagulant was positive in 16.6% cases and anticardiolipin antibodies in 10% cases. Combined defects were seen in seven patients. Conclusion: There is a significant risk of RPL in pregnant women with thrombophilias. Therefore, screening for thrombophilias may be justified in pregnant women with unexplained recurrent fetal wastage, especially in second and third trimester.

  20. Loss of RASSF2 Enhances Tumorigencity of Lung Cancer Cells and Confers Resistance to Chemotherapy

    Directory of Open Access Journals (Sweden)

    Jennifer Clark

    2012-01-01

    Full Text Available RASSF2 is a novel pro-apoptotic effector of K-Ras that is frequently inactivated in a variety of primary tumors by promoter methylation. Inactivation of RASSF2 enhances K-Ras-mediated transformation and overexpression of RASSF2 suppresses tumor cell growth. In this study, we confirm that RASSF2 and K-Ras form an endogenous complex, validating that RASSF2 is a bona fide K-Ras effector. We adopted an RNAi approach to determine the effects of inactivation of RASSF2 on the transformed phenotype of lung cancer cells containing an oncogenic K-Ras. Loss of RASSF2 expression resulted in a more aggressive phenotype that was characterized by enhanced cell proliferation and invasion, decreased cell adhesion, the ability to grow in an anchorage-independent manner and cell morphological changes. This enhanced transformed phenotype of the cells correlated with increased levels of activated AKT, indicating that RASSF2 can modulate Ras signaling pathways. Loss of RASSF2 expression also confers resistance to taxol and cisplatin, two frontline therapeutics for the treatment of lung cancer. Thus we have shown that inactivation of RASSF2, a process that occurs frequently in primary tumors, enhances the transforming potential of activated K-Ras and our data suggests that RASSF2 may be a novel candidate for epigenetic-based therapy in lung cancer.

  1. Modeling of optical losses in perovskite solar cells

    Science.gov (United States)

    Taghavi, M. Javad; Houshmand, Mohammad; Zandi, M. Hossein; Gorji, Nima E.

    2016-09-01

    The optical losses within the structure of hybrid perovskite solar cells are investigated using only the optical properties of each layer e.g. refractive index and extinction coefficient. This model allows calculating the transmission/reflection rates at the interfaces and absorption loss within any layer. Then, the short circuit current density and loss percentage are calculated versus the perovskite and TiO2 thicknesses from 50 nm to 150 nm. To make our calculations closer to reality, we extracted the optical properties of each device component from the literature reports on glass/TCO/TiO2/perovskite/metal. The simulations were fitted with the experimental results of some relevant references. Our simulations show that ITO transmits the light better than SnO2 as the TCO front electrode, and the light reflection at both sides of the perovskite layer, e.g. at TiO2/perovskite and perovskite/Spiro-OMeTAD, is lower than 25%. The light interference and multiple reflections have been accounted in our calculations and finally we showed that a thicker TiO2 and perovskite cause more optical loss in current density due to stronger absorption.

  2. Verification, Validation and Credibility Assessment of a Computational Model of the Advanced Resistive Exercise Device (ARED)

    Science.gov (United States)

    Werner, C. R.; Humphreys, B. T.; Mulugeta, L.

    2014-01-01

    The Advanced Resistive Exercise Device (ARED) is the resistive exercise device used by astronauts on the International Space Station (ISS) to mitigate bone loss and muscle atrophy due to extended exposure to microgravity (micro g). The Digital Astronaut Project (DAP) has developed a multi-body dynamics model of biomechanics models for use in spaceflight exercise physiology research and operations. In an effort to advance model maturity and credibility of the ARED model, the DAP performed verification, validation and credibility (VV and C) assessment of the analyses of the model in accordance to NASA-STD-7009 'Standards for Models and Simulations'.

  3. Optic neuritis and retinal ganglion cell loss in a chronic murine model of multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Thomas eQuinn

    2011-08-01

    Full Text Available Multiple sclerosis (MS and its animal model experimental autoimmune encephalomyelitis (EAE are neurodegenerative diseases with characteristic inflammatory demyelination in the central nervous system, including the optic nerve. Neuronal and axonal damage is considered to be the main cause of long-term disability in patients with MS. Neuronal loss, including retinal ganglion cell (RGC apoptosis in eyes with optic neuritis, also occurs in EAE. However, there is significant variability in the clinical course and level of neuronal damage in MS and EAE. The current studies examine the mechanisms and kinetics of RGC loss in C57BL/6 mice immunized with myelin oligodendrocyte glycoprotein to induce a chronic EAE disease. Clinical progression of EAE was scored daily and vision was assessed by optokinetic responses. At various time points, RGCs were counted and optic nerves were examined for inflammatory cell infiltration. Almost all EAE mice develop optic neuritis by day 15 post-immunization; however, RGC loss is delayed in these mice. No RGC loss is detected 25 days post-immunization, whereas RGC numbers in EAE mice significantly and progressively decrease compared to controls from 35-50 days post-immunization. The delayed time course of RGC loss is in stark contrast to that reported in relapsing EAE, as well as in rats with chronic EAE. Results suggest that different clinical disease courses of optic nerve inflammation may trigger distinct mechanisms of neuronal damage, or RGCs in different rodent strains may have variable resistance to neuronal degeneration.

  4. Synergistic impacts of habitat loss and fragmentation on model ecosystems

    Science.gov (United States)

    Purves, Drew W.; Tittensor, Derek P.; Harfoot, Michael B. J.

    2016-01-01

    Habitat loss and fragmentation are major threats to biodiversity, yet separating their effects is challenging. We use a multi-trophic, trait-based, and spatially explicit general ecosystem model to examine the independent and synergistic effects of these processes on ecosystem structure. We manipulated habitat by removing plant biomass in varying spatial extents, intensities, and configurations. We found that emergent synergistic interactions of loss and fragmentation are major determinants of ecosystem response, including population declines and trophic pyramid shifts. Furthermore, trait-mediated interactions, such as a disproportionate sensitivity of large-sized organisms to fragmentation, produce significant effects in shaping responses. We also show that top-down regulation mitigates the effects of land use on plant biomass loss, suggesting that models lacking these interactions—including most carbon stock models—may not adequately capture land-use change impacts. Our results have important implications for understanding ecosystem responses to environmental change, and assessing the impacts of habitat fragmentation. PMID:27655763

  5. Pea powdery mildew er1 resistance is associated to loss-of-function mutations at a MLO homologous locus.

    Science.gov (United States)

    Pavan, Stefano; Schiavulli, Adalgisa; Appiano, Michela; Marcotrigiano, Angelo R; Cillo, Fabrizio; Visser, Richard G F; Bai, Yuling; Lotti, Concetta; Ricciardi, Luigi

    2011-12-01

    The powdery mildew disease affects several crop species and is also one of the major threats for pea (Pisum sativum L.) cultivation all over the world. The recessive gene er1, first described over 60 years ago, is well known in pea breeding, as it still maintains its efficiency as a powdery mildew resistance source. Genetic and phytopathological features of er1 resistance are similar to those of barley, Arabidopsis, and tomato mlo powdery mildew resistance, which is caused by the loss of function of specific members of the MLO gene family. Here, we describe the obtainment of a novel er1 resistant line by experimental mutagenesis with the alkylating agent diethyl sulfate. This line was found to carry a single nucleotide polymorphism in the PsMLO1 gene sequence, predicted to result in premature termination of translation and a non-functional protein. A cleaved amplified polymorphic sequence (CAPS) marker was developed on the mutation site and shown to be fully co-segregating with resistance in F(2) individuals. Sequencing of PsMLO1 from three powdery mildew resistant cultivars also revealed the presence of loss-of-function mutations. Taken together, results reported in this study strongly indicate the identity between er1 and mlo resistances and are expected to be of great breeding importance for the development of resistant cultivars via marker-assisted selection.

  6. Modeling Hospitals’ Adaptive Capacity during a Loss of Infrastructure Services

    Directory of Open Access Journals (Sweden)

    Eric D. Vugrin

    2015-01-01

    Full Text Available Resilience in hospitals - their ability to withstand, adapt to, and rapidly recover from disruptive events - is vital to their role as part of national critical infrastructure. This paper presents a model to provide planning guidance to decision makers about how to make hospitals more resilient against possible disruption scenarios. This model represents a hospital’s adaptive capacities that are leveraged to care for patients during loss of infrastructure services (power, water, etc.. The model is an optimization that reallocates and substitutes resources to keep patients in a high care state or allocates resources to allow evacuation if necessary. An illustrative example demonstrates how the model might be used in practice.

  7. Loss Function Based Ranking in Two-Stage, Hierarchical Models

    Science.gov (United States)

    Lin, Rongheng; Louis, Thomas A.; Paddock, Susan M.; Ridgeway, Greg

    2009-01-01

    Performance evaluations of health services providers burgeons. Similarly, analyzing spatially related health information, ranking teachers and schools, and identification of differentially expressed genes are increasing in prevalence and importance. Goals include valid and efficient ranking of units for profiling and league tables, identification of excellent and poor performers, the most differentially expressed genes, and determining “exceedances” (how many and which unit-specific true parameters exceed a threshold). These data and inferential goals require a hierarchical, Bayesian model that accounts for nesting relations and identifies both population values and random effects for unit-specific parameters. Furthermore, the Bayesian approach coupled with optimizing a loss function provides a framework for computing non-standard inferences such as ranks and histograms. Estimated ranks that minimize Squared Error Loss (SEL) between the true and estimated ranks have been investigated. The posterior mean ranks minimize SEL and are “general purpose,” relevant to a broad spectrum of ranking goals. However, other loss functions and optimizing ranks that are tuned to application-specific goals require identification and evaluation. For example, when the goal is to identify the relatively good (e.g., in the upper 10%) or relatively poor performers, a loss function that penalizes classification errors produces estimates that minimize the error rate. We construct loss functions that address this and other goals, developing a unified framework that facilitates generating candidate estimates, comparing approaches and producing data analytic performance summaries. We compare performance for a fully parametric, hierarchical model with Gaussian sampling distribution under Gaussian and a mixture of Gaussians prior distributions. We illustrate approaches via analysis of standardized mortality ratio data from the United States Renal Data System. Results show that SEL

  8. Modeling Phosphorous Losses from Seasonal Manure Application Schemes

    Science.gov (United States)

    Menzies, E.; Walter, M. T.

    2015-12-01

    Excess nutrient loading, especially nitrogen and phosphorus, to surface waters is a common and significant problem throughout the United States. While pollution remediation efforts are continuously improving, the most effective treatment remains to limit the source. Appropriate timing of fertilizer application to reduce nutrient losses is currently a hotly debated topic in the Northeastern United States; winter spreading of manure is under special scrutiny. We plan to evaluate the loss of phosphorous to surface waters from agricultural systems under varying seasonal fertilization schemes in an effort to determine the impacts of fertilizers applied throughout the year. The Cayuga Lake basin, located in the Finger Lakes region of New York State, is a watershed dominated by agriculture where a wide array of land management strategies can be found. The evaluation will be conducted on the Fall Creek Watershed, a large sub basin in the Cayuga Lake Watershed. The Fall Creek Watershed covers approximately 33,000 ha in central New York State with approximately 50% of this land being used for agriculture. We plan to use the Soil and Water Assessment Tool (SWAT) to model a number of seasonal fertilization regimes such as summer only spreading and year round spreading (including winter applications), as well as others. We will use the model to quantify the phosphorous load to surface waters from these different fertilization schemes and determine the impacts of manure applied at different times throughout the year. More detailed knowledge about how seasonal fertilization schemes impact phosphorous losses will provide more information to stakeholders concerning the impacts of agriculture on surface water quality. Our results will help farmers and extensionists make more informed decisions about appropriate timing of manure application for reduced phosphorous losses and surface water degradation as well as aid law makers in improving policy surrounding manure application.

  9. Thin stillage fractionation using ultrafiltration: resistance in series model.

    Science.gov (United States)

    Arora, Amit; Dien, Bruce S; Belyea, Ronald L; Wang, Ping; Singh, Vijay; Tumbleson, M E; Rausch, Kent D

    2009-02-01

    The corn based dry grind process is the most widely used method in the US for fuel ethanol production. Fermentation of corn to ethanol produces whole stillage after ethanol is removed by distillation. It is centrifuged to separate thin stillage from wet grains. Thin stillage contains 5-10% solids. To concentrate solids of thin stillage, it requires evaporation of large amounts of water and maintenance of evaporators. Evaporator maintenance requires excess evaporator capacity at the facility, increasing capital expenses, requiring plant slowdowns or shut downs and results in revenue losses. Membrane filtration is one method that could lead to improved value of thin stillage and may offer an alternative to evaporation. Fractionation of thin stillage using ultrafiltration was conducted to evaluate membranes as an alternative to evaporators in the ethanol industry. Two regenerated cellulose membranes with molecular weight cut offs of 10 and 100 kDa were evaluated. Total solids (suspended and soluble) contents recovered through membrane separation process were similar to those from commercial evaporators. Permeate flux decline of thin stillage using a resistance in series model was determined. Each of the four components of total resistance was evaluated experimentally. Effects of operating variables such as transmembrane pressure and temperature on permeate flux rate and resistances were determined and optimum conditions for maximum flux rates were evaluated. Model equations were developed to evaluate the resistance components that are responsible for fouling and to predict total flux decline with respect to time. Modeling results were in agreement with experimental results (R(2) > 0.98).

  10. SPUF - a simple polyurethane foam mass loss and response model.

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, Michael L.; Lemmon, Gordon H.

    2003-07-01

    A Simple PolyUrethane Foam (SPUF) mass loss and response model has been developed to predict the behavior of unconfined, rigid, closed-cell, polyurethane foam-filled systems exposed to fire-like heat fluxes. The model, developed for the B61 and W80-0/1 fireset foam, is based on a simple two-step mass loss mechanism using distributed reaction rates. The initial reaction step assumes that the foam degrades into a primary gas and a reactive solid. The reactive solid subsequently degrades into a secondary gas. The SPUF decomposition model was implemented into the finite element (FE) heat conduction codes COYOTE [1] and CALORE [2], which support chemical kinetics and dynamic enclosure radiation using 'element death.' A discretization bias correction model was parameterized using elements with characteristic lengths ranging from 1-mm to 1-cm. Bias corrected solutions using the SPUF response model with large elements gave essentially the same results as grid independent solutions using 100-{micro}m elements. The SPUF discretization bias correction model can be used with 2D regular quadrilateral elements, 2D paved quadrilateral elements, 2D triangular elements, 3D regular hexahedral elements, 3D paved hexahedral elements, and 3D tetrahedron elements. Various effects to efficiently recalculate view factors were studied -- the element aspect ratio, the element death criterion, and a 'zombie' criterion. Most of the solutions using irregular, large elements were in agreement with the 100-{micro}m grid-independent solutions. The discretization bias correction model did not perform as well when the element aspect ratio exceeded 5:1 and the heated surface was on the shorter side of the element. For validation, SPUF predictions using various sizes and types of elements were compared to component-scale experiments of foam cylinders that were heated with lamps. The SPUF predictions of the decomposition front locations were compared to the front locations

  11. Modeling deployment of Pierce’s disease resistant grapevines

    Science.gov (United States)

    Deployment of Pierce’s disease resistant grapevines is a key solution to mitigating economic losses caused by Xylella fastidiosa. While Pierce’s disease resistant grapevines under development display mild symptoms and have lower bacterial populations than susceptible varieties, all appear to remain ...

  12. Modeling effects of conservation grassland losses on amphibian habitat

    Science.gov (United States)

    Mushet, David M.; Neau, Jordan L.; Euliss, Ned H.

    2014-01-01

    Amphibians provide many ecosystem services valued by society. However, populations have declined globally with most declines linked to habitat change. Wetlands and surrounding terrestrial grasslands form habitat for amphibians in the North American Prairie Pothole Region (PPR). Wetland drainage and grassland conversion have destroyed or degraded much amphibian habitat in the PPR. However, conservation grasslands can provide alternate habitat. In the United States, the Conservation Reserve Program (CRP) is the largest program maintaining grasslands on agricultural lands. We used an ecosystem services model (InVEST) parameterized for the PPR to quantify amphibian habitat over a six-year period (2007–2012). We then quantified changes in availability of amphibian habitat under various land-cover scenarios representing incremental losses (10%, 25%, 50%, 75%, and 100%) of CRP grasslands from 2012 levels. The area of optimal amphibian habitat in the four PPR ecoregions modeled (i.e., Northern Glaciated Plains, Northwestern Glaciated Plains, Lake Agassiz Plain, Des Moines Lobe) declined by approximately 22%, from 3.8 million ha in 2007 to 2.9 million ha in 2012. These losses were driven by the conversion of CRP grasslands to croplands, primarily for corn and soybean production. Our modeling identified an additional 0.8 million ha (26%) of optimal amphibian habitat that would be lost if remaining CRP lands are returned to crop production. An economic climate favoring commodity production over conservation has resulted in substantial losses of amphibian habitat across the PPR that will likely continue into the future. Other regions of the world face similar challenges to maintaining amphibian habitats.

  13. Loss of Ikbkap Causes Slow, Progressive Retinal Degeneration in a Mouse Model of Familial Dysautonomia

    Science.gov (United States)

    Ramirez, Grisela

    2016-01-01

    Abstract Familial dysautonomia (FD) is an autosomal recessive congenital neuropathy that is caused by a mutation in the gene for inhibitor of kappa B kinase complex-associated protein (IKBKAP). Although FD patients suffer from multiple neuropathies, a major debilitation that affects their quality of life is progressive blindness. To determine the requirement for Ikbkap in the developing and adult retina, we generated Ikbkap conditional knockout (CKO) mice using a TUBA1a promoter-Cre (Tα1-Cre). In the retina, Tα1-Cre expression is detected predominantly in retinal ganglion cells (RGCs). At 6 months, significant loss of RGCs had occurred in the CKO retinas, with the greatest loss in the temporal retina, which is the same spatial phenotype observed in FD, Leber hereditary optic neuropathy, and dominant optic atrophy. Interestingly, the melanopsin-positive RGCs were resistant to degeneration. By 9 months, signs of photoreceptor degeneration were observed, which later progressed to panretinal degeneration, including RGC and photoreceptor loss, optic nerve thinning, Müller glial activation, and disruption of layers. Taking these results together, we conclude that although Ikbkap is not required for normal development of RGCs, its loss causes a slow, progressive RGC degeneration most severely in the temporal retina, which is later followed by indirect photoreceptor loss and complete retinal disorganization. This mouse model of FD is not only useful for identifying the mechanisms mediating retinal degeneration, but also provides a model system in which to attempt to test therapeutics that may mitigate the loss of vision in FD patients. PMID:27699209

  14. What do we gain with Probabilistic Flood Loss Models?

    Science.gov (United States)

    Schroeter, K.; Kreibich, H.; Vogel, K.; Merz, B.; Lüdtke, S.

    2015-12-01

    The reliability of flood loss models is a prerequisite for their practical usefulness. Oftentimes, traditional uni-variate damage models as for instance depth-damage curves fail to reproduce the variability of observed flood damage. Innovative multi-variate probabilistic modelling approaches are promising to capture and quantify the uncertainty involved and thus to improve the basis for decision making. In this study we compare the predictive capability of two probabilistic modelling approaches, namely Bagging Decision Trees and Bayesian Networks and traditional stage damage functions which are cast in a probabilistic framework. For model evaluation we use empirical damage data which are available from computer aided telephone interviews that were respectively compiled after the floods in 2002, 2005, 2006 and 2013 in the Elbe and Danube catchments in Germany. We carry out a split sample test by sub-setting the damage records. One sub-set is used to derive the models and the remaining records are used to evaluate the predictive performance of the model. Further we stratify the sample according to catchments which allows studying model performance in a spatial transfer context. Flood damage estimation is carried out on the scale of the individual buildings in terms of relative damage. The predictive performance of the models is assessed in terms of systematic deviations (mean bias), precision (mean absolute error) as well as in terms of reliability which is represented by the proportion of the number of observations that fall within the 95-quantile and 5-quantile predictive interval. The reliability of the probabilistic predictions within validation runs decreases only slightly and achieves a very good coverage of observations within the predictive interval. Probabilistic models provide quantitative information about prediction uncertainty which is crucial to assess the reliability of model predictions and improves the usefulness of model results.

  15. Accommodating environmental variation in population models: metaphysiological biomass loss accounting.

    Science.gov (United States)

    Owen-Smith, Norman

    2011-07-01

    1. There is a pressing need for population models that can reliably predict responses to changing environmental conditions and diagnose the causes of variation in abundance in space as well as through time. In this 'how to' article, it is outlined how standard population models can be modified to accommodate environmental variation in a heuristically conducive way. This approach is based on metaphysiological modelling concepts linking populations within food web contexts and underlying behaviour governing resource selection. Using population biomass as the currency, population changes can be considered at fine temporal scales taking into account seasonal variation. Density feedbacks are generated through the seasonal depression of resources even in the absence of interference competition. 2. Examples described include (i) metaphysiological modifications of Lotka-Volterra equations for coupled consumer-resource dynamics, accommodating seasonal variation in resource quality as well as availability, resource-dependent mortality and additive predation, (ii) spatial variation in habitat suitability evident from the population abundance attained, taking into account resource heterogeneity and consumer choice using empirical data, (iii) accommodating population structure through the variable sensitivity of life-history stages to resource deficiencies, affecting susceptibility to oscillatory dynamics and (iv) expansion of density-dependent equations to accommodate various biomass losses reducing population growth rate below its potential, including reductions in reproductive outputs. Supporting computational code and parameter values are provided. 3. The essential features of metaphysiological population models include (i) the biomass currency enabling within-year dynamics to be represented appropriately, (ii) distinguishing various processes reducing population growth below its potential, (iii) structural consistency in the representation of interacting populations and

  16. Core-suppressed AC loss and strand-moderated contact resistance in a Nb3Sn Rutherford cable

    NARCIS (Netherlands)

    Sumption, M.D.; Collings, E.W.; Scanlan, R.M.; Nijhuis, A.; Kate, ten H.H.J.

    1999-01-01

    Calorimetric measurements of AC loss and hence interstrand contact resistance (ICR), have been performed on two types of Rutherford cable wound with unplated Nb3Sn strand. One of the cable types was furnished with a thin core of AISI 316L stainless steel and the other was left uncored. The cables we

  17. Post-Domicide Artefacts: Mapping Resistance and Loss onto Palestinian House-Keys

    Directory of Open Access Journals (Sweden)

    Scott Webster

    2016-11-01

    Full Text Available This article is concerned with the experiences of domicide—that is, the suffering caused by the deliberate destruction of home by human agency in pursuit of certain objectives—faced by Palestinians as a legacy (as well as in the present of the ongoing conflict with Israel. Existing scholarly and activist research provides some essential data about these experiences, but intellectual contributions remain primarily focused on the act of demolition or displacement. This act alone does not constitute ‘domicide’. What must follow is an attempt by the displaced to grapple with the whole affective dimension of being forcibly separated from home and the symbolic and creative responses that it begets. The significance house-keys have acquired within Palestinian inter-familial and communal customs, as well as within cultural (reproduction, provides insight into this suffering. Attachment to the house-key is viewed as emblematic of feelings towards the lost home—a continuation of that connection by other means. This article explores the range of ways ation of the key’s symbolic value has been reconfigured as it permeates different arenas of cultural production and activity, and how the keys have come to embody both loss of home and resistance of the goals of Israeli domicide.

  18. The effect of pioglitazone and resistance training on body composition in older men and women undergoing hypocaloric weight loss.

    Science.gov (United States)

    Shea, M Kyla; Nicklas, Barbara J; Marsh, Anthony P; Houston, Denise K; Miller, Gary D; Isom, Scott; Miller, Michael E; Carr, J Jeffrey; Lyles, Mary F; Harris, Tamara B; Kritchevsky, Stephen B

    2011-08-01

    Age-related increases in ectopic fat accumulation are associated with greater risk for metabolic and cardiovascular diseases, and physical disability. Reducing skeletal muscle fat and preserving lean tissue are associated with improved physical function in older adults. PPARγ-agonist treatment decreases abdominal visceral adipose tissue (VAT) and resistance training preserves lean tissue, but their effect on ectopic fat depots in nondiabetic overweight adults is unclear. We examined the influence of pioglitazone and resistance training on body composition in older (65-79 years) nondiabetic overweight/obese men (n = 48, BMI = 32.3 ± 3.8 kg/m(2)) and women (n = 40, BMI = 33.3 ± 4.9 kg/m(2)) during weight loss. All participants underwent a 16-week hypocaloric weight-loss program and were randomized to receive pioglitazone (30 mg/day) or no pioglitazone with or without resistance training, following a 2 × 2 factorial design. Regional body composition was measured at baseline and follow-up using computed tomography (CT). Lean mass was measured using dual X-ray absorptiometry. Men lost 6.6% and women lost 6.5% of initial body mass. The percent of fat loss varied across individual compartments. Men who were given pioglitazone lost more visceral abdominal fat than men who were not given pioglitazone (-1,160 vs. -647 cm(3), P = 0.007). Women who were given pioglitazone lost less thigh subcutaneous fat (-104 vs. -298 cm(3), P = 0.002). Pioglitazone did not affect any other outcomes. Resistance training diminished thigh muscle loss in men and women (resistance training vs. no resistance training men: -43 vs. -88 cm(3), P = 0.005; women: -34 vs. -59 cm(3), P = 0.04). In overweight/obese older men undergoing weight loss, pioglitazone increased visceral fat loss and resistance training reduced skeletal muscle loss. Additional studies are needed to clarify the observed gender differences and evaluate how these changes in body composition influence functional status.

  19. Noise-induced hearing loss: new animal models.

    Science.gov (United States)

    Christie, Kevin W; Eberl, Daniel F

    2014-10-01

    This article presents research findings from two invertebrate model systems with potential to advance both the understanding of noise-induced hearing loss mechanisms and the development of putative therapies to reduce human noise damage. Work on sea anemone hair bundles, which resemble auditory hair cells, has revealed secretions that exhibit astonishing healing properties not only for damaged hair bundles, but also for vertebrate lateral line neuromasts. We present progress on identifying functional components of the secretions, and their mechanisms of repair. The second model, the Johnston's organ in Drosophila, is also genetically homologous to hair cells and shows noise-induced hearing loss similar to vertebrates. Drosophila offers genetic and molecular insight into noise sensitivity and pathways that can be manipulated to reduce stress and damage from noise. Using the comparative approach is a productive avenue to understanding basic mechanisms, in this case cellular responses to noise trauma. Expanding study of these systems may accelerate identification of strategies to reduce or prevent noise damage in the human ear.

  20. Loss of Microbiota-Mediated Colonization Resistance to Clostridium difficile Infection With Oral Vancomycin Compared With Metronidazole.

    Science.gov (United States)

    Lewis, Brittany B; Buffie, Charlie G; Carter, Rebecca A; Leiner, Ingrid; Toussaint, Nora C; Miller, Liza C; Gobourne, Asia; Ling, Lilan; Pamer, Eric G

    2015-11-15

    Antibiotic administration disrupts the intestinal microbiota, increasing susceptibility to pathogens such as Clostridium difficile. Metronidazole or oral vancomycin can cure C. difficile infection, and administration of these agents to prevent C. difficile infection in high-risk patients, although not sanctioned by Infectious Disease Society of America guidelines, has been considered. The relative impacts of metronidazole and vancomycin on the intestinal microbiota and colonization resistance are unknown. We investigated the effect of brief treatment with metronidazole and/or oral vancomycin on susceptibility to C. difficile, vancomycin-resistant Enterococcus, carbapenem-resistant Klebsiella pneumoniae, and Escherichia coli infection in mice. Although metronidazole resulted in transient loss of colonization resistance, oral vancomycin markedly disrupted the microbiota, leading to prolonged loss of colonization resistance to C. difficile infection and dense colonization by vancomycin-resistant Enterococcus, K. pneumoniae, and E. coli. Our results demonstrate that vancomycin, and to a lesser extent metronidazole, are associated with marked intestinal microbiota destruction and greater risk of colonization by nosocomial pathogens.

  1. Loss of CMD2‐mediated resistance to cassava mosaic disease in plants regenerated through somatic embryogenesis

    Science.gov (United States)

    Chauhan, Raj Deepika; Wagaba, Henry; Moll, Theodore; Alicai, Titus; Miano, Douglas; Carrington, James C.; Taylor, Nigel J.

    2016-01-01

    Summary Cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) are the two most important viral diseases affecting cassava production in Africa. Three sources of resistance are employed to combat CMD: polygenic recessive resistance, termed CMD1, the dominant monogenic type, named CMD2, and the recently characterized CMD3. The farmer‐preferred cultivar TME 204 carries inherent resistance to CMD mediated by CMD2, but is highly susceptible to CBSD. Selected plants of TME 204 produced for RNA interference (RNAi)‐mediated resistance to CBSD were regenerated via somatic embryogenesis and tested in confined field trials in East Africa. Although micropropagated, wild‐type TME 204 plants exhibited the expected levels of resistance, all plants regenerated via somatic embryogenesis were found to be highly susceptible to CMD. Glasshouse studies using infectious clones of East African cassava mosaic virus conclusively demonstrated that the process of somatic embryogenesis used to regenerate cassava caused the resulting plants to become susceptible to CMD. This phenomenon could be replicated in the two additional CMD2‐type varieties TME 3 and TME 7, but the CMD1‐type cultivar TMS 30572 and the CMD3‐type cultivar TMS 98/0505 maintained resistance to CMD after passage through somatic embryogenesis. Data are presented to define the specific tissue culture step at which the loss of CMD resistance occurs and to show that the loss of CMD2‐mediated resistance is maintained across vegetative generations. These findings reveal new aspects of the widely used technique of somatic embryogenesis, and the stability of field‐level resistance in CMD2‐type cultivars presently grown by farmers in East Africa, where CMD pressure is high. PMID:26662210

  2. Testing and Modeling of Contact Problems in Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    As a part of the efforts towards a professional and reliable numerical tool for resistance welding engineers, this Ph.D. project is dedicated to refining the numerical models related to the interface behavior. An FE algorithm for the contact problems in resistance welding has been developed...... together two or three cylindrical parts as well as disc-ring pairs of dissimilar metals. The tests have demonstrated the effectiveness of the model. A theoretical and experimental study is performed on the contact resistance aiming at a more reliable model for numerical simulation of resistance welding....... The model currently employed is evaluated. It is found that the model may underestimate the constriction resistance because it is based on the assumption of continual contact area. A new model is proposed on the constriction resistance in resistance welding. A parametric study is performed on the contact...

  3. Dominance, biomass and extinction resistance determine the consequences of biodiversity loss for multiple coastal ecosystem processes.

    Science.gov (United States)

    Davies, Thomas W; Jenkins, Stuart R; Kingham, Rachel; Kenworthy, Joseph; Hawkins, Stephen J; Hiddink, Jan G

    2011-01-01

    Key ecosystem processes such as carbon and nutrient cycling could be deteriorating as a result of biodiversity loss. However, currently we lack the ability to predict the consequences of realistic species loss on ecosystem processes. The aim of this study was to test whether species contributions to community biomass can be used as surrogate measures of their contribution to ecosystem processes. These were gross community productivity in a salt marsh plant assemblage and an intertidal macroalgae assemblage; community clearance of microalgae in sessile suspension feeding invertebrate assemblage; and nutrient uptake in an intertidal macroalgae assemblage. We conducted a series of biodiversity manipulations that represented realistic species extinction sequences in each of the three contrasting assemblages. Species were removed in a subtractive fashion so that biomass was allowed to vary with each species removal, and key ecosystem processes were measured at each stage of community disassembly. The functional contribution of species was directly proportional to their contribution to community biomass in a 1:1 ratio, a relationship that was consistent across three contrasting marine ecosystems and three ecosystem processes. This suggests that the biomass contributed by a species to an assemblage can be used to approximately predict the proportional decline in an ecosystem process when that species is lost. Such predictions represent "worst case scenarios" because, over time, extinction resilient species can offset the loss of biomass associated with the extinction of competitors. We also modelled a "best case scenario" that accounts for compensatory responses by the extant species with the highest per capita contribution to ecosystem processes. These worst and best case scenarios could be used to predict the minimum and maximum species required to sustain threshold values of ecosystem processes in the future.

  4. Risk-Based Causal Modeling of Airborne Loss of Separation

    Science.gov (United States)

    Geuther, Steven C.; Shih, Ann T.

    2015-01-01

    Maintaining safe separation between aircraft remains one of the key aviation challenges as the Next Generation Air Transportation System (NextGen) emerges. The goals of the NextGen are to increase capacity and reduce flight delays to meet the aviation demand growth through the 2025 time frame while maintaining safety and efficiency. The envisioned NextGen is expected to enable high air traffic density, diverse fleet operations in the airspace, and a decrease in separation distance. All of these factors contribute to the potential for Loss of Separation (LOS) between aircraft. LOS is a precursor to a potential mid-air collision (MAC). The NASA Airspace Operations and Safety Program (AOSP) is committed to developing aircraft separation assurance concepts and technologies to mitigate LOS instances, therefore, preventing MAC. This paper focuses on the analysis of causal and contributing factors of LOS accidents and incidents leading to MAC occurrences. Mid-air collisions among large commercial aircraft are rare in the past decade, therefore, the LOS instances in this study are for general aviation using visual flight rules in the years 2000-2010. The study includes the investigation of causal paths leading to LOS, and the development of the Airborne Loss of Separation Analysis Model (ALOSAM) using Bayesian Belief Networks (BBN) to capture the multi-dependent relations of causal factors. The ALOSAM is currently a qualitative model, although further development could lead to a quantitative model. ALOSAM could then be used to perform impact analysis of concepts and technologies in the AOSP portfolio on the reduction of LOS risk.

  5. Modelling the Epistemic Uncertainty in the Vulnerability Assessment Component of an Earthquake Loss Model

    Science.gov (United States)

    Crowley, H.; Modica, A.

    2009-04-01

    Loss estimates have been shown in various studies to be highly sensitive to the methodology employed, the seismicity and ground-motion models, the vulnerability functions, and assumed replacement costs (e.g. Crowley et al., 2005; Molina and Lindholm, 2005; Grossi, 2000). It is clear that future loss models should explicitly account for these epistemic uncertainties. Indeed, a cause of frequent concern in the insurance and reinsurance industries is precisely the fact that for certain regions and perils, available commercial catastrophe models often yield significantly different loss estimates. Of equal relevance to many users is the fact that updates of the models sometimes lead to very significant changes in the losses compared to the previous version of the software. In order to model the epistemic uncertainties that are inherent in loss models, a number of different approaches for the hazard, vulnerability, exposure and loss components should be clearly and transparently applied, with the shortcomings and benefits of each method clearly exposed by the developers, such that the end-users can begin to compare the results and the uncertainty in these results from different models. This paper looks at an application of a logic-tree type methodology to model the epistemic uncertainty in the vulnerability component of a loss model for Tunisia. Unlike other countries which have been subjected to damaging earthquakes, there has not been a significant effort to undertake vulnerability studies for the building stock in Tunisia. Hence, when presented with the need to produce a loss model for a country like Tunisia, a number of different approaches can and should be applied to model the vulnerability. These include empirical procedures which utilise observed damage data, and mechanics-based methods where both the structural characteristics and response of the buildings are analytically modelled. Some preliminary applications of the methodology are presented and discussed

  6. E-model MOS Estimate Improvement through Jitter Buffer Packet Loss Modelling

    Directory of Open Access Journals (Sweden)

    Adrian Kovac

    2011-01-01

    Full Text Available Proposed article analyses dependence of MOS as a voice call quality (QoS measure estimated through ITU-T E-model under real network conditions with jitter. In this paper, a method of jitter effect is proposed. Jitter as voice packet time uncertainty appears as increased packet loss caused by jitter memory buffer under- or overflow. Jitter buffer behaviour at receiver’s side is modelled as Pareto/D/1/K system with Pareto-distributed packet interarrival times and its performance is experimentally evaluated by using statistic tools. Jitter buffer stochastic model is then incorporated into E-model in an additive manner accounting for network jitter effects via excess packet loss complementing measured network packet loss. Proposed modification of E-model input parameter adds two degrees of freedom in modelling: network jitter and jitter buffer size.

  7. Weight Loss Decreases Inherent and Allergic Methacholine Hyperresponsiveness in Mouse Models of Diet-Induced Obese Asthma.

    Science.gov (United States)

    Ather, Jennifer L; Chung, Michael; Hoyt, Laura R; Randall, Matthew J; Georgsdottir, Anna; Daphtary, Nirav A; Aliyeva, Minara I; Suratt, Benjamin T; Bates, Jason H T; Irvin, Charles G; Russell, Sheila R; Forgione, Patrick M; Dixon, Anne E; Poynter, Matthew E

    2016-08-01

    Obese asthma presents with inherent hyperresponsiveness to methacholine or augmented allergen-driven allergic asthma, with an even greater magnitude of methacholine hyperresponsiveness. These physiologic parameters and accompanying obese asthma symptoms can be reduced by successful weight loss, yet the underlying mechanisms remain incompletely understood. We implemented mouse models of diet-induced obesity, dietary and surgical weight loss, and environmental allergen exposure to examine the mechanisms and mediators of inherent and allergic obese asthma. We report that the methacholine hyperresponsiveness in these models of inherent obese asthma and obese allergic asthma manifests in distinct anatomical compartments but that both are amenable to interventions that induce substantial weight loss. The inherent obese asthma phenotype, with characteristic increases in distal airspace tissue resistance and tissue elastance, is associated with elevated proinflammatory cytokines that are reduced with dietary weight loss. Surprisingly, bariatric surgery-induced weight loss further elevates these cytokines while reducing methacholine responsiveness to levels similar to those in lean mice or in formerly obese mice rendered lean through dietary intervention. In contrast, the obese allergic asthma phenotype, with characteristic increases in central airway resistance, is not associated with increased adaptive immune responses, yet diet-induced weight loss reduces methacholine hyperresponsiveness without altering immunological variables. Diet-induced weight loss is effective in models of both inherent and allergic obese asthma, and our examination of the fecal microbiome revealed that the obesogenic Firmicutes/Bacteroidetes ratio was normalized after diet-induced weight loss. Our results suggest that structural, immunological, and microbiological factors contribute to the manifold presentations of obese asthma.

  8. Hair loss and regeneration performed on animal models.

    Science.gov (United States)

    Orasan, Meda Sandra; Roman, Iulia Ioana; Coneac, Andrei; Muresan, Adriana; Orasan, Remus Ioan

    2016-01-01

    Research in the field of reversal hair loss remains a challenging subject. As Minoxidil 2% or 5% and Finasteride are so far the only FDA approved topical treatments for inducing hair regrowth, research is necessary in order to improve therapeutical approach in alopecia. In vitro studies have focused on cultures of a cell type - dermal papilla or organ culture of isolated cell follicles. In vivo research on this topic was performed on mice, rats, hamsters, rabbits, sheep and monkeys, taking into consideration the advantages and disadvantages of each animal model and the depilation options. Further studies are required not only to compare the efficiency of different therapies but more importantly to establish their long term safety.

  9. Acoustic puncture assist device versus loss of resistance technique for epidural space identification

    Directory of Open Access Journals (Sweden)

    Amit Kumar Mittal

    2016-01-01

    Full Text Available Background and Aims: The conventional techniques of epidural space (EDS identification based on loss of resistance (LOR have a higher chance of complications, patchy analgesia and epidural failure, which can be minimised by objective confirmation of space before catheter placement. Acoustic puncture assist device (APAD technique objectively confirms EDS, thus enhancing success, with lesser complications. This study was planned with the objective to evaluate the APAD technique and compare it to LOR technique for EDS identification and its correlation with ultrasound guided EDS depth. Methods: In this prospective study, the lumbar vertebral spaces were scanned by the ultrasound for measuring depth of the EDS and later correlated with procedural depth measured by either of the technique (APAD or LOR. The data were subjected to descriptive statistics; the concordance correlation coefficient and Bland-Altman analysis with 95% confidence limits. Results: Acoustic dip in pitch and descent in pressure tracing on EDS localisation was observed among the patients of APAD group. Analysis of concordance correlation between the ultrasonography (USG depth and APAD or LOR depth was significant (r ≥ 0.97 in both groups. Bland-Altman analysis revealed a mean difference of 0.171cm in group APAD and 0.154 cm in group LOR. The 95% limits of agreement for the difference between the two measurements were − 0.569 and 0.226 cm in APAD and − 0.530 to 0.222 cm in LOR group. Conclusion: We found APAD to be a precise tool for objective localisation of the EDS, co-relating well with the pre-procedural USG depth of EDS.

  10. Acoustic puncture assist device versus loss of resistance technique for epidural space identification.

    Science.gov (United States)

    Mittal, Amit Kumar; Goel, Nitesh; Chowdhury, Itee; Shah, Shagun Bhatia; Singh, Brijesh Pratap; Jakhar, Pradeep

    2016-05-01

    The conventional techniques of epidural space (EDS) identification based on loss of resistance (LOR) have a higher chance of complications, patchy analgesia and epidural failure, which can be minimised by objective confirmation of space before catheter placement. Acoustic puncture assist device (APAD) technique objectively confirms EDS, thus enhancing success, with lesser complications. This study was planned with the objective to evaluate the APAD technique and compare it to LOR technique for EDS identification and its correlation with ultrasound guided EDS depth. In this prospective study, the lumbar vertebral spaces were scanned by the ultrasound for measuring depth of the EDS and later correlated with procedural depth measured by either of the technique (APAD or LOR). The data were subjected to descriptive statistics; the concordance correlation coefficient and Bland-Altman analysis with 95% confidence limits. Acoustic dip in pitch and descent in pressure tracing on EDS localisation was observed among the patients of APAD group. Analysis of concordance correlation between the ultrasonography (USG) depth and APAD or LOR depth was significant (r ≥ 0.97 in both groups). Bland-Altman analysis revealed a mean difference of 0.171cm in group APAD and 0.154 cm in group LOR. The 95% limits of agreement for the difference between the two measurements were - 0.569 and 0.226 cm in APAD and - 0.530 to 0.222 cm in LOR group. We found APAD to be a precise tool for objective localisation of the EDS, co-relating well with the pre-procedural USG depth of EDS.

  11. Loss of glial lazarillo, a homolog of apolipoprotein D, reduces lifespan and stress resistance in Drosophila.

    Science.gov (United States)

    Sanchez, Diego; López-Arias, Begoña; Torroja, Laura; Canal, Inmaculada; Wang, Xiaohui; Bastiani, Michael J; Ganfornina, Maria D

    2006-04-01

    The vertebrate Apolipoprotein D (ApoD) is a lipocalin secreted from subsets of neurons and glia during neural development and aging . A strong correlation exists between ApoD overexpression and numerous nervous system pathologies as well as obesity, diabetes, and many forms of cancer . However, the exact relationship between the function of ApoD and the pathophysiology of these diseases is still unknown. We have generated loss-of-function Drosophila mutants for the Glial Lazarillo (GLaz) gene , a homolog of ApoD in the fruit fly, mainly expressed in subsets of adult glial cells. The absence of GLaz reduces the organism's resistance to oxidative stress and starvation and shortens male lifespan. The mutant flies exhibit a smaller body mass due to a lower amount of neutral lipids stored in the fat body. Apoptotic neural cell death increases in aged flies or upon paraquat treatment, which also impairs neural function as assessed by behavioral tests. The higher sensitivity to oxidative stress and starvation and the reduced fat storage revert to control levels when a GFP-GLaz fusion protein is expressed under the control of the GLaz natural promoter. Finally, GLaz mutants have a higher concentration of lipid peroxidation products, pointing to a lipid peroxidation protection or scavenging as the mechanism of action for this lipocalin. In agreement with Walker et al. (, in this issue of Current Biology), who analyze the effects of overexpressing GLaz, we conclude that GLaz has a protective role in stress situations and that its absence reduces lifespan and accelerates neurodegeneration.

  12. Bayes Estimation for Inverse Rayleigh Model under Different Loss Functions

    Directory of Open Access Journals (Sweden)

    Guobing Fan

    2015-04-01

    Full Text Available The inverse Rayleigh distribution plays an important role in life test and reliability domain. The aim of this article is study the Bayes estimation of parameter of inverse Rayleigh distribution. Bayes estimators are obtained under squared error loss, LINEX loss and entropy loss functions on the basis of quasi-prior distribution. Comparisons in terms of risks with the estimators of parameter under three loss functions are also studied. Finally, a numerical example is used to illustrate the results.

  13. Estimating the magnitude of prediction uncertainties for field-scale P loss models

    Science.gov (United States)

    Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that model predictions are inherently uncertain, few studies have addressed prediction uncertainties using P loss models. In this study, an uncertainty analysis for the Annual P Loss Estima...

  14. Estimating Agricultural Losses using Flood Modeling for Rural Area

    Directory of Open Access Journals (Sweden)

    Muhadi Nur Atirah

    2017-01-01

    Full Text Available Flooding is the most significant natural hazard in Malaysia in terms of population affected, frequency, flood extent, flood duration and social economic damage. Flooding causes loss of lives, injuries, property damage and leave some economic damage to the country especially when it occurs in a rural area where the main income is dependent on agricultural area. This study focused on flooding in oil palm plantations, rubber plantations and fruits and vegetables area. InfoWorks ICM was used to develop a flood model to study the impact of flooding and to mitigate the floods using a retention pond. Later, Geographical Information System (GIS together with the flood model were used for the analysis on flood damage assessment and management of flood risk. The estimated total damage for three different flood event; 10 ARI, 50 ARI and 100 ARI involved millions of ringgits. In reducing the flood impact along the Selangor River, retention pond was suggested, modeled and tested. By constructing retention pond, flood extents in agricultural area were reduced significantly by 60.49% for 10 ARI, 45.39% for 50 ARI and 46.54% for 100 ARI.

  15. Analytical Modeling Of The Steinmetz Coefficient For Single-Phase Transformer Eddy Current Loss Prediction

    Directory of Open Access Journals (Sweden)

    T. Aly Saandy

    2015-08-01

    Full Text Available Abstract This article presents to an analytical calculation methodology of the Steinmetz coefficient applied to the prediction of Eddy current loss in a single-phase transformer. Based on the electrical circuit theory the active power consumed by the core is expressed analytically in function of the electrical parameters as resistivity and the geometrical dimensions of the core. The proposed modeling approach is established with the duality parallel series. The required coefficient is identified from the empirical Steinmetz data based on the experimented active power expression. To verify the relevance of the model validations both by simulations with two in two different frequencies and measurements were carried out. The obtained results are in good agreement with the theoretical approach and the practical results.

  16. Model parameter uncertainty analysis for an annual field-scale P loss model

    Science.gov (United States)

    Bolster, Carl H.; Vadas, Peter A.; Boykin, Debbie

    2016-08-01

    Phosphorous (P) fate and transport models are important tools for developing and evaluating conservation practices aimed at reducing P losses from agricultural fields. Because all models are simplifications of complex systems, there will exist an inherent amount of uncertainty associated with their predictions. It is therefore important that efforts be directed at identifying, quantifying, and communicating the different sources of model uncertainties. In this study, we conducted an uncertainty analysis with the Annual P Loss Estimator (APLE) model. Our analysis included calculating parameter uncertainties and confidence and prediction intervals for five internal regression equations in APLE. We also estimated uncertainties of the model input variables based on values reported in the literature. We then predicted P loss for a suite of fields under different management and climatic conditions while accounting for uncertainties in the model parameters and inputs and compared the relative contributions of these two sources of uncertainty to the overall uncertainty associated with predictions of P loss. Both the overall magnitude of the prediction uncertainties and the relative contributions of the two sources of uncertainty varied depending on management practices and field characteristics. This was due to differences in the number of model input variables and the uncertainties in the regression equations associated with each P loss pathway. Inspection of the uncertainties in the five regression equations brought attention to a previously unrecognized limitation with the equation used to partition surface-applied fertilizer P between leaching and runoff losses. As a result, an alternate equation was identified that provided similar predictions with much less uncertainty. Our results demonstrate how a thorough uncertainty and model residual analysis can be used to identify limitations with a model. Such insight can then be used to guide future data collection and model

  17. Muscle mass loss and intermuscular lipid accumulation were associated with insulin resistance in patients receiving hemodialysis

    Institute of Scientific and Technical Information of China (English)

    WANG Hui-ling; DING Ting-ting; LU Shi; XU Ye; TIAN Jun; HU Wei-feng; ZHANG Jin-yuan

    2013-01-01

    Background An accelerated muscle wasting was the pivotal factor for protein-energy wasting in end stage renal disease.However,very few researches have examined the skeletal muscle quantity and quality in clinical patients.This study investigated the muscle morphologic changes by magnetic resonance imaging (MRI) and analyzed the related factors in hemodialysis patients.Methods Fifty-eight patients receiving maintenance hemodialysis (HD) were investigated and 28 healthy adults with gender and age matched were used as controls (Control).Anthropometry,cytokine factors,and laboratory data were measured.The muscle and intermuscular adipose tissues (IMAT) were analyzed via a Thigh MRI.The bicep samples were observed after HE staining.Homeostatic model assessment of insulin resistance (HOMA-IR) was measured and their association with muscle wasting was analyzed.Results HD patients tended to have a lower protein diet,anthropometry data,and serum albumin,but the C reactive protein and interleukin-6 increased significantly.The MRI showed that HD patients had less muscle mass and a lower muscle/total ratio,but the fat/muscle and IMAT was higher when compared to the Control group.The muscle fiber showed atrophy and fat accumulation in the biceps samples come from the HD patients.Moreover,we found that the HD patients presented with a high level of plasma fasting insulin and increased HOMA-IR which negatively correlated with the muscle/total ratio,but positively with the fat/muscle ratio.Conclusions Muscle wasting presented early before an obvious malnutrition condition emerged in HD patients.The main morphological change was muscle atrophy along with intermuscular lipid accumulation.Insulin resistance was associated with muscle wasting in dialysis patients.

  18. Steady state cooling flow models with gas loss for normal elliptical galaxies

    Science.gov (United States)

    Sarazin, Craig L.; Ashe, Gregory A.

    1989-01-01

    A grid of cooling flow models for the hot gas in normal elliptical galaxies is calculated, including the loss of gas due to inhomogeneous cooling. The loss process is modeled as a distributed sink for the gas with the rate of loss being proportional to the local cooling rate. The cooling flow models with gas loss have smaller sonic radii, smaller inflow rates in their central regions, lower densities, and higher temperatures than homogeneous models. The reduction in the amount of hot gas flowing into the center of the models brings the models into much better agreement with the observed X-ray surface brightness profiles of elliptical galaxies. However, there is a large dispersion in the observed X-ray luminosities of ellipticals, and this cannot be explained by variations in the efficiency of gas loss. The gas-loss models have X-ray surface brightness profiles which are much less centrally peaked than the no-gas-loss models.

  19. Epidemiological models for the spread of anti-malarial resistance

    Directory of Open Access Journals (Sweden)

    Antia R

    2003-02-01

    Full Text Available Abstract Background The spread of drug resistance is making malaria control increasingly difficult. Mathematical models for the transmission dynamics of drug sensitive and resistant strains can be a useful tool to help to understand the factors that influence the spread of drug resistance, and they can therefore help in the design of rational strategies for the control of drug resistance. Methods We present an epidemiological framework to investigate the spread of anti-malarial resistance. Several mathematical models, based on the familiar Macdonald-Ross model of malaria transmission, enable us to examine the processes and parameters that are critical in determining the spread of resistance. Results In our simplest model, resistance does not spread if the fraction of infected individuals treated is less than a threshold value; if drug treatment exceeds this threshold, resistance will eventually become fixed in the population. The threshold value is determined only by the rates of infection and the infectious periods of resistant and sensitive parasites in untreated and treated hosts, whereas the intensity of transmission has no influence on the threshold value. In more complex models, where hosts can be infected by multiple parasite strains or where treatment varies spatially, resistance is generally not fixed, but rather some level of sensitivity is often maintained in the population. Conclusions The models developed in this paper are a first step in understanding the epidemiology of anti-malarial resistance and evaluating strategies to reduce the spread of resistance. However, specific recommendations for the management of resistance need to wait until we have more data on the critical parameters underlying the spread of resistance: drug use, spatial variability of treatment and parasite migration among areas, and perhaps most importantly, cost of resistance.

  20. Investigating radiation belt losses though numerical modelling of precipitating fluxes

    Directory of Open Access Journals (Sweden)

    C. J. Rodger

    2004-11-01

    Full Text Available It has been suggested that whistler-induced electron precipitation (WEP may be the most significant inner radiation belt loss process for some electron energy ranges. One area of uncertainty lies in identifying a typical estimate of the precipitating fluxes from the examples given in the literature to date. Here we aim to solve this difficulty through modelling satellite and ground-based observations of onset and decay of the precipitation and its effects in the ionosphere by examining WEP-produced Trimpi perturbations in subionospheric VLF transmissions. In this study we find that typical Trimpi are well described by the effects of WEP spectra derived from the AE-5 inner radiation belt model for typical precipitating energy fluxes. This confirms the validity of the radiation belt lifetimes determined in previous studies using these flux parameters. We find that the large variation in observed Trimpi perturbation size occurring over time scales of minutes to hours is primarily due to differing precipitation flux levels rather than changing WEP spectra. Finally, we show that high-time resolution measurements during the onset of Trimpi perturbations should provide a useful signature for discriminating WEP Trimpi from non-WEP Trimpi, due to the pulsed nature of the WEP arrival.

  1. Exact series model of Langevin transducers with internal losses.

    Science.gov (United States)

    Nishamol, P A; Ebenezer, D D

    2014-03-01

    An exact series method is presented to analyze classical Langevin transducers with arbitrary boundary conditions. The transducers consist of an axially polarized piezoelectric solid cylinder sandwiched between two elastic solid cylinders. All three cylinders are of the same diameter. The length to diameter ratio is arbitrary. Complex piezoelectric and elastic coefficients are used to model internal losses. Solutions to the exact linearized governing equations for each cylinder include four series. Each term in each series is an exact solution to the governing equations. Bessel and trigonometric functions that form complete and orthogonal sets in the radial and axial directions, respectively, are used in the series. Asymmetric transducers and boundary conditions are modeled by using axially symmetric and anti-symmetric sets of functions. All interface and boundary conditions are satisfied in a weighted-average sense. The computed input electrical admittance, displacement, and stress in transducers are presented in tables and figures, and are in very good agreement with those obtained using atila-a finite element package for the analysis of sonar transducers. For all the transducers considered in the analysis, the maximum difference between the first three resonance frequencies calculated using the present method and atila is less than 0.03%.

  2. Analgesic efficacy using loss of resistance to air vs. saline in combined spinal epidural technique for labour analgesia.

    Science.gov (United States)

    Leo, S; Lim, Y; Sia, A T H

    2008-09-01

    Identification of the epidural space is often performed using the loss of resistance technique to either air or saline. We sought to investigate if the medium used affected the quality of analgesia obtained by parturients who received labour epidurals. We conducted a retrospective audit of labour epidurals performed on nulliparous parturients in our institution from May 2003 to March 2005. All epidural catheters were inserted by senior obstetric anaesthetists using a combined spinal epidural technique. The following information was recorded: parturients' demographic data, loss of resistance technique used, type and amount of local anaesthetic solution administered, complications encountered during procedure, pre-block and post-block pain scores, incidence of breakthrough pain requiring supplemental medication and post-block side-effects. Data from 2848 patients were collected and analysed; 56% of patients made up the saline group and 44% the air group. Patients in both groups had similar demographic profiles and similar incidences of complications and post-block side-effects. However patients in the air group had a higher incidence of recurrent breakthrough pain P = 0.023). We also identified three other factors that were associated with an increased incidence of recurrent breakthrough pain; administration of pre-block oxytocin, sitting position of the parturient during the procedure and the use of intrathecal bupivacaine for induction of analgesia. Our findings suggest that a loss of resistance to air is associated with a higher incidence of recurrent breakthrough pain among parturients who received combined spinal epidural analgesia for labour than a loss of resistance to saline.

  3. Durable broad-spectrum powdery mildew resistance in pea er1 plants is conferred by natural loss-of-function mutations in PsMLO1

    NARCIS (Netherlands)

    Humphry, M.; Reinstädler, A.; Ivanov, S.; Bisseling, T.; Panstruga, R.

    2011-01-01

    Loss-of-function alleles of plant-specific MLO (Mildew Resistance Locus O) genes confer broad-spectrum powdery mildew resistance in monocot (barley) and dicot (Arabidopsis thaliana, tomato) plants. Recessively inherited powdery mildew resistance in pea (Pisum sativum) er1 plants is, in many aspects,

  4. Thermal resistance model for CSP central receivers

    Science.gov (United States)

    de Meyer, O. A. J.; Dinter, F.; Govender, S.

    2016-05-01

    The receiver design and heliostat field aiming strategy play a vital role in the heat transfer efficiency of the receiver. In molten salt external receivers, the common operating temperature of the heat transfer fluid or molten salt ranges between 285°C to 565°C. The optimum output temperature of 565°C is achieved by adjusting the mass flow rate of the molten salt through the receiver. The reflected solar radiation onto the receiver contributes to the temperature rise in the molten salt by means of heat transfer. By investigating published work on molten salt external receiver operating temperatures, corresponding receiver tube surface temperatures and heat losses, a model has been developed to obtain a detailed thermographic representation of the receiver. The steady state model uses a receiver flux map as input to determine: i) heat transfer fluid mass flow rate through the receiver to obtain the desired molten salt output temperature of 565°C, ii) receiver surface temperatures iii) receiver tube temperatures iv) receiver efficiency v) pressure drop across the receiver and vi) corresponding tube strain per panel.

  5. Mass Loss in 2D ZAMS Stellar Models

    OpenAIRE

    Lovekin, C. C.

    2011-01-01

    A large number of massive stars are known to rotate, resulting in significant distortion and variation in surface temperature from the pole to the equator. Radiatively driven mass loss is temperature dependent, so rapid rotation produces variation in mass loss and angular momentum loss rates across the surface of the star, which is expected to affect the evolution of rapidly rotating massive stars. In this work, we investigate the two dimensional effects of rotation on radiatively driven mass...

  6. Mass Loss in 2D ZAMS Stellar Models

    OpenAIRE

    Lovekin, C. C.

    2011-01-01

    A large number of massive stars are known to rotate, resulting in significant distortion and variation in surface temperature from the pole to the equator. Radiatively driven mass loss is temperature dependent, so rapid rotation produces variation in mass loss and angular momentum loss rates across the surface of the star, which is expected to affect the evolution of rapidly rotating massive stars. In this work, we investigate the two dimensional effects of rotation on radiatively driven mass...

  7. Identification of the epidural space: loss of resistance with air, lidocaine, or the combination of air and lidocaine.

    Science.gov (United States)

    Evron, Samuel; Sessler, Daniel; Sadan, Oscar; Boaz, Mona; Glezerman, Marek; Ezri, Tiberiu

    2004-07-01

    The ideal technique for identifying the epidural space remains unclear. Five-hundred-forty-seven women in labor who requested epidural analgesia were randomly allocated to three groups according to the technique by which the epidural space was identified: 1) loss-of-resistance with air (air; n = 180), 2) loss-of-resistance with lidocaine (lidocaine; n = 185), and 3) loss-of-resistance with both air and lidocaine (air-plus-lidocaine; n = 182). We assessed ease of epidural catheter insertion, characteristics of the blockade, quality of analgesia, and complications. The inability to thread the epidural catheter occurred in 16% of the air, 4% of the lidocaine, and 3% of the air-plus-lidocaine patients (P air group had unblocked segments (6.6% versus 3.2% and 2.2%, respectively; P air group (1.7% versus 0% in the other two groups; P space with air was more difficult and caused more dural punctures than with lidocaine or air plus lidocaine. Additionally, sequential use of air and lidocaine had no advantage over lidocaine alone.

  8. Simulation of Irrigation Water Loss Based on VSMB Model

    Institute of Scientific and Technical Information of China (English)

    Hongwen ZHOU; Luxin ZHAI; Wenxing LU; Dongxu LIU

    2016-01-01

    The low degree of development and utilization as well as the contradiction between supply and demand of water resources in Huangshui River basin are the main restricting factors of the local agricultural development. The study on the simulation of irrigation water loss based on the VSMB model has very important significance to strengthening regional water management and improving water resource utilization efficiency. Five groundwater wells were set up to carry out the farmland irrigation water infiltration and the experimental study on groundwater dynamic effect. Two soil moisture monitoring sites were set up in two typical plots of Daxia and Guanting irrigation area at the same time and TDR300 was used to monitor four kinds of deep soil moisture( 10 cm,30 cm,50 cm and 70 cm). On this basis,the VSMB model was used to study the irrigation water loss in the irrigation area of Yellow River valley of Qinghai Province,including soil moisture content,the actual evapotranspiration,infiltration,runoff,groundwater buried depth and so on. The results showed that the water consumption caused by soil evaporation and crop transpiration accounted for 46. 4% and 24. 1% of the total precipitation plus irrigation,respectively,and the leakage accounted for 30. 3% and 60. 6% of the total precipitation plus irrigation,respectively,from March 1,2013 to April 30,and from August 1 to September 30. The actual evaporation of the GT- TR1 and GT- TR2 sites in the whole year of 2013 was 632. 6 mm and 646. 9 mm,respectively,and the leakage accounted for 2. 6% and 1. 2% of the total precipitation plus irrigation,respectively. RMSE of the simulation results of the groundwater depth in Daxia irrigation area during the two periods was 92. 3 mm and 27. 7 mm,respectively. And RMSE of the simulation results of the water content of soil profile in the two monitoring sites of Guanting irrigation area was 2. 04% and 5. 81%,respectively,indicating that the simulation results were reliable.

  9. Modeling of Micro Deval abrasion loss based on some rock properties

    Science.gov (United States)

    Capik, Mehmet; Yilmaz, Ali Osman

    2017-10-01

    Aggregate is one of the most widely used construction material. The quality of the aggregate is determined using some testing methods. Among these methods, the Micro Deval Abrasion Loss (MDAL) test is commonly used for the determination of the quality and the abrasion resistance of aggregate. The main objective of this study is to develop models for the prediction of MDAL from rock properties, including uniaxial compressive strength, Brazilian tensile strength, point load index, Schmidt rebound hardness, apparent porosity, void ratio Cerchar abrasivity index and Bohme abrasion test are examined. Additionally, the MDAL is modeled using simple regression analysis and multiple linear regression analysis based on the rock properties. The study shows that the MDAL decreases with the increase of uniaxial compressive strength, Brazilian tensile strength, point load index, Schmidt rebound hardness and Cerchar abrasivity index. It is also concluded that the MDAL increases with the increase of apparent porosity, void ratio and Bohme abrasion test. The modeling results show that the models based on Bohme abrasion test and L type Schmidt rebound hardness give the better forecasting performances for the MDAL. More models, including the uniaxial compressive strength, the apparent porosity and Cerchar abrasivity index, are developed for the rapid estimation of the MDAL of the rocks. The developed models were verified by statistical tests. Additionally, it can be stated that the proposed models can be used as a forecasting for aggregate quality.

  10. Weight-loss changes PPAR expression, reduces atherosclerosis and improves cardiovascular function in obese insulin-resistant mice

    Energy Technology Data Exchange (ETDEWEB)

    Verreth, Wim; Verhamme, Peter; Pelat, Michael; Ganame, Javier; Bielicki, John K.; Mertens, Ann; Quarck, Rozenn; Benhabiles, Nora; Marguerie, Gerard; Mackness, Bharti; Mackness, Mike; Ninio, Ewa; Herregods, Marie-Christine; Balligand, Jean-Luc; Holvoet, Paul

    2003-09-01

    Weight-loss in obese insulin-resistant, but not in insulin-sensitive, persons reduces CHD risk. It is not known to what extent changes in the adipose gene expression profile are important for reducing CHD risk. We studied the effect of diet restriction-induced weight-loss on gene expression in adipose tissue, atherosclerosis and cardiovascular function in mice with combined leptin and LDL-receptor deficiency. Obesity, hypertriglyceridemia and insulin-resistance are associated with hypertension, impaired left ventricle function and accelerated atherosclerosis in those mice. Diet restriction during 12 weeks caused a 45% weight-loss and changes in the gene expression in adipose tissue of PPARa and PPAR? and of key genes regulating glucose transport and insulin sensitivity, lipid metabolism, oxidative stress and inflammation, most of which are under the transcriptional control of PPARs. These changes were associated with increased insulin-sensitivity, decreased hypertriglyceridemia, reduced mean 24-hour blood pressure and heart rate, restored circadian variations of blood pressure and heart rate, increased ejection fraction, and reduced atherosclerosis. Thus, induction of PPARa and PPAR? in adipose tissue is a key mechanism for reducing atherosclerosis and improving cardiovascular function resulting from weight-loss. Our observations point to the critical role of PPARs in the pathogenesis of cardiovascular features of the metabolic syndrome.

  11. Effects of water vapor density on cutaneous resistance to evaporative water loss and body temperature in green tree frogs (Hyla cinerea).

    Science.gov (United States)

    Wygoda, Mark L; Kersten, Constance A

    2013-01-01

    Increased cutaneous resistance to evaporative water loss (Rc) in tree frogs results in decreased water loss rate and increased body temperature. We examined sensitivity of Rc to water vapor density (WVD) in Hyla cinerea by exposing individual frogs and agar models to four different WVD environments and measuring cutaneous evaporative water loss rate and body temperature simultaneously using a gravimetric wind tunnel measuring system. We found that water loss rate varied inversely and body temperature directly with WVD but that models were affected to a greater extent than were animals. Mean Rc was significantly different between the highest WVD environment and each of the three drier environments but did not differ among the drier environments, indicating that Rc initially increases and then reaches a plateau in response to decreasing WVD. Rc was equivalent when calculated using either WVD difference or WVD deficit as the driving force for evaporation. We also directly observed secretions from cutaneous glands while measuring body temperature and tested secretions and skin samples for the presence of lipids. We found that irregular transient body temperature depressions observed during wind tunnel trials occur due to evaporative cooling from intermittent skin secretions containing lipids, although we were unable to identify lipid-secreting glands.

  12. Frequent gain and loss of resistance against tobacco mosaic virus (TMV) in Nicotiana Species

    Science.gov (United States)

    Resistance (R) genes represent one of the most divergent gene families in plants. Novel resistance function might arise through point mutations or sequence exchanges between paralogues. Sequence exchanges between homologues may generate a large number of distinct genes. In fact, some R gene families...

  13. Testing a Model of IR Radiative Losses: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Vignola, F.; Long, C. N.; Reda, I.

    2009-08-01

    Thermopile pyranometers exhibit IR radiative losses that affect global and diffuse shortwave measurements made with first class thermopile based instruments. Pyrgeometers can be used to measure the sky temperature and are used to calculate the pyranometer?s IR radiative losses.

  14. Loss of accuracy using smeared properties in composite beam modeling

    Science.gov (United States)

    Liu, Ning

    Advanced composite materials have broad, proven applications in many engineering systems ranging from sports equipment sectors to components on the space shuttle because of their lightweight characteristics and significantly high stiffness. Together with this merit of composite materials is the challenge of improving computational simulation process for composites analysis. Composite structures, particularly composite laminates, usually consist of many layers with different lay-up angles. The anisotropic and heterogeneous features render 3D finite element analysis (FEA) computationally expensive in terms of the computational time and the computing power. At the constituent level, composite materials are heterogeneous. But quite often one homogenizes each layer of composites, i.e. lamina, and uses the homogenized material properties as averaged (smeared) values of those constituent materials for analysis. This is an approach extensively used in design and analysis of composite laminates. Furthermore, many industries tempted to use smeared properties at the laminate level to further reduce the model of composite structures. At this scale, smeared properties are averaged material properties that are weighted by the layer thickness. Although this approach has the advantage of saving computational time and cost of modeling significantly, the prediction of the structural responses may not be accurate, particularly the pointwise stress distribution. Therefore, it is important to quantify the loss of accuracy when one uses smeared properties. In this paper, several different benchmark problems are carefully investigated in order to exemplify the effect of the smeared properties on the global behavior and pointwise stress distribution of the composite beam. In the classical beam theory, both Newtonian method and variational method include several ad hoc assumptions to construct the model, however, these assumptions are avoided if one uses variational asymptotic method. VABS

  15. Analysis and modeling of resistive switching mechanisms oriented to resistive random-access memory

    Institute of Scientific and Technical Information of China (English)

    Huang Da; Wu Jun-Jie; Tang Yu-Hua

    2013-01-01

    With the progress of the semiconductor industry,the resistive random-access memory (RAM) has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms.We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models.Finally,simulations are presented.We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms,which are applied to explain their resistive switchings.

  16. Genetic pathway in acquisition and loss of vancomycin resistance in a methicillin resistant Staphylococcus aureus (MRSA strain of clonal type USA300.

    Directory of Open Access Journals (Sweden)

    Susana Gardete

    2012-02-01

    Full Text Available An isolate of the methicillin-resistant Staphylococcus aureus (MRSA clone USA300 with reduced susceptibility to vancomycin (SG-R (i.e, vancomycin-intermediate S. aureus, VISA and its susceptible "parental" strain (SG-S were recovered from a patient at the end and at the beginning of an unsuccessful vancomycin therapy. The VISA phenotype was unstable in vitro generating a susceptible revertant strain (SG-rev. The availability of these 3 isogenic strains allowed us to explore genetic correlates of antibiotic resistance as it emerged in vivo. Compared to the susceptible isolate, both the VISA and revertant strains carried the same point mutations in yycH, vraG, yvqF and lspA genes and a substantial deletion within an intergenic region. The revertant strain carried a single additional frameshift mutation in vraS which is part of two component regulatory system VraSR. VISA isolate SG-R showed complex alterations in phenotype: decreased susceptibility to other antibiotics, slow autolysis, abnormal cell division and increased thickness of cell wall. There was also altered expression of 239 genes including down-regulation of major virulence determinants. All phenotypic properties and gene expression profile returned to parental levels in the revertant strain. Introduction of wild type yvqF on a multicopy plasmid into the VISA strain caused loss of resistance along with loss of all the associated phenotypic changes. Introduction of the wild type vraSR into the revertant strain caused recovery of VISA type resistance. The yvqF/vraSR operon seems to function as an on/off switch: mutation in yvqF in strain SG-R turns on the vraSR system, which leads to increase in vancomycin resistance and down-regulation of virulence determinants. Mutation in vraS in the revertant strain turns off this regulatory system accompanied by loss of resistance and normal expression of virulence genes. Down-regulation of virulence genes may provide VISA strains with a "stealth

  17. Modelling the Loss of Steel-Concrete Bonds in Corroded Reinforced Concrete Beams

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    2007-01-01

    The existing stochastic models for deterioration of reinforced concrete structures is extended by adding modelling of "loss of bond" due to corrosion between the reinforcement bars and the surrounding concrete.......The existing stochastic models for deterioration of reinforced concrete structures is extended by adding modelling of "loss of bond" due to corrosion between the reinforcement bars and the surrounding concrete....

  18. Acquired resistance to EGFR tyrosine kinase inhibitors in cancer cells is mediated by loss of IGF-binding proteins

    Science.gov (United States)

    Guix, Marta; Faber, Anthony C.; Wang, Shizhen Emily; Olivares, Maria Graciela; Song, Youngchul; Qu, Sherman; Rinehart, Cammie; Seidel, Brenda; Yee, Douglas; Arteaga, Carlos L.; Engelman, Jeffrey A.

    2008-01-01

    Although some cancers are initially sensitive to EGFR tyrosine kinase inhibitors (TKIs), resistance invariably develops. We investigated mechanisms of acquired resistance to the EGFR TKI gefitinib by generating gefitinib-resistant (GR) A431 squamous cancer cells. In GR cells, gefitinib reduced phosphorylation of EGFR, ErbB-3, and Erk but not Akt. These cells also showed hyperphosphorylation of the IGFI receptor (IGFIR) and constitutive association of IRS-1 with PI3K. Inhibition of IGFIR signaling disrupted the association of IRS-1 with PI3K and restored the ability of gefitinib to downregulate PI3K/Akt signaling and to inhibit GR cell growth. Gene expression analyses revealed that GR cells exhibited markedly reduced IGF-binding protein 3 (IGFBP-3) and IGFBP-4 RNA. Addition of recombinant IGFBP-3 restored the ability of gefitinib to downregulate PI3K/Akt signaling and to inhibit cell growth. Finally, gefitinib treatment of mice with A431 xenografts in combination with an IGFIR-specific monoclonal antibody prevented tumor recurrence, whereas each drug given alone was unable to do so. These data suggest that loss of expression of IGFBPs in tumor cells treated with EGFR TKIs derepresses IGFIR signaling, which in turn mediates resistance to EGFR antagonists. Moreover, combined therapeutic inhibition of EGFR and IGFIR may abrogate this acquired mechanism of drug resistance and is thus worthy of prospective clinical investigation. PMID:18568074

  19. Probabilistic, Multivariable Flood Loss Modeling on the Mesoscale with BT-FLEMO.

    Science.gov (United States)

    Kreibich, Heidi; Botto, Anna; Merz, Bruno; Schröter, Kai

    2017-04-01

    Flood loss modeling is an important component for risk analyses and decision support in flood risk management. Commonly, flood loss models describe complex damaging processes by simple, deterministic approaches like depth-damage functions and are associated with large uncertainty. To improve flood loss estimation and to provide quantitative information about the uncertainty associated with loss modeling, a probabilistic, multivariable Bagging decision Tree Flood Loss Estimation MOdel (BT-FLEMO) for residential buildings was developed. The application of BT-FLEMO provides a probability distribution of estimated losses to residential buildings per municipality. BT-FLEMO was applied and validated at the mesoscale in 19 municipalities that were affected during the 2002 flood by the River Mulde in Saxony, Germany. Validation was undertaken on the one hand via a comparison with six deterministic loss models, including both depth-damage functions and multivariable models. On the other hand, the results were compared with official loss data. BT-FLEMO outperforms deterministic, univariable, and multivariable models with regard to model accuracy, although the prediction uncertainty remains high. An important advantage of BT-FLEMO is the quantification of prediction uncertainty. The probability distribution of loss estimates by BT-FLEMO well represents the variation range of loss estimates of the other models in the case study. © 2016 Society for Risk Analysis.

  20. Assessing Stop-Loss Policy Options through Personnel Flow Modeling

    Science.gov (United States)

    2014-01-01

    precipitated the adoption of stop-loss and that can aff ect decisions regarding its replacement. Performance of Base-Case Systems with Stop-Loss 21...SANTA MONICA, CA 90407-2138 OFFICES SANTA MONICA, CA WASHINGTON, DC PITTSBURGH, PA NEW ORLEANS, LA/JACKSON, MS BOSTON, MA DOHA, QA ABU DHABI, AE CAMBRIDGE, UK BRUSSELS, BE REPRESENTATIVE OFFICE MEXICO CITY, MX www.rand.org

  1. Primary Hyperparathyroidism: The Influence of Bone Marrow Adipose Tissue on Bone Loss and of Osteocalcin on Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Maira L. Mendonça

    Full Text Available OBJECTIVES: Bone marrow adipose tissue has been associated with low bone mineral density. However, no data exist regarding marrow adipose tissue in primary hyperparathyroidism, a disorder associated with bone loss in conditions of high bone turnover. The objective of the present study was to investigate the relationship between marrow adipose tissue, bone mass and parathyroid hormone. The influence of osteocalcin on the homeostasis model assessment of insulin resistance was also evaluated. METHODS: This was a cross-sectional study conducted at a university hospital, involving 18 patients with primary hyperparathyroidism (PHPT and 21 controls (CG. Bone mass was assessed by dual-energy x-ray absorptiometry and marrow adipose tissue was assessed by 1H magnetic resonance spectroscopy. The biochemical evaluation included the determination of parathyroid hormone, osteocalcin, glucose and insulin levels. RESULTS: A negative association was found between the bone mass at the 1/3 radius and parathyroid hormone levels (r = -0.69; p<0.01. Marrow adipose tissue was not significantly increased in patients (CG = 32.8±11.2% vs PHPT = 38.6±12%. The serum levels of osteocalcin were higher in patients (CG = 8.6±3.6 ng/mL vs PHPT = 36.5±38.4 ng/mL; p<0.005, but no associations were observed between osteocalcin and insulin or between insulin and both marrow adipose tissue and bone mass. CONCLUSION: These results suggest that the increment of adipogenesis in the bone marrow microenvironment under conditions of high bone turnover due to primary hyperparathyroidism is limited. Despite the increased serum levels of osteocalcin due to primary hyperparathyroidism, these patients tend to have impaired insulin sensitivity.

  2. Cefoxitin resistance mediated by loss of a porin in clinical strains of Klebsiella pneumoniae and Escherichia coli

    Directory of Open Access Journals (Sweden)

    Ananthan S

    2005-01-01

    Full Text Available PURPOSE: Porins are outer membrane protein (OMP that form water filled channels that permit the diffusion of small hydrophilic solutes like -lactam antibiotics across the outer membrane. Two major porins that facilitate diffusion of antimicrobials have been described in Klebsiella spp. and Escherichia coli. The present study was carried out to examine the role of porins among Extended Spectrum -Lactamase (ESBL and AmpC -Lactamase positive strains of Klebsiella spp. and E.coli. METHODS: Preparation of OMP from phenotypically characterized clinical isolates K.pneumoniae and E.coli and the separation of the proteins by sodium dodecyl sulfate - polyacrylamide gel electrophoresis were performed as per a previously described procedure. RESULTS: OMP analysis revealed that cefoxitin and ceftazidime resistance was mediated by loss of a porin Omp K35 in the isolates of K.pneumoniae and E.coli. CONCLUSIONS: Loss of porin mediated resistance mechanism against cefoxitin was observed among the multidrug resistant K.pneumoniae and E.coli.

  3. Numerical Acoustic Models Including Viscous and Thermal losses: Review of Existing and New Methods

    DEFF Research Database (Denmark)

    Andersen, Peter Risby; Cutanda Henriquez, Vicente; Aage, Niels

    2017-01-01

    This work presents an updated overview of numerical methods including acoustic viscous and thermal losses. Numerical modelling of viscothermal losses has gradually become more important due to the general trend of making acoustic devices smaller. Not including viscothermal acoustic losses in such...

  4. Parameter uncertainty analysis for the annual phosphorus loss estimator (APLE) model

    Science.gov (United States)

    Technical abstract: Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that model predictions are inherently uncertain, few studies have addressed prediction uncertainties using P loss models. In this study, we conduct an uncertainty analys...

  5. Life history trade-off moderates model predictions of diversity loss from climate change.

    Science.gov (United States)

    Moor, Helen

    2017-01-01

    Climate change can trigger species range shifts, local extinctions and changes in diversity. Species interactions and dispersal capacity are important mediators of community responses to climate change. The interaction between multispecies competition and variation in dispersal capacity has recently been shown to exacerbate the effects of climate change on diversity and to increase predictions of extinction risk dramatically. Dispersal capacity, however, is part of a species' overall ecological strategy and are likely to trade off with other aspects of its life history that influence population growth and persistence. In plants, a well-known example is the trade-off between seed mass and seed number. The presence of such a trade-off might buffer the diversity loss predicted by models with random but neutral (i.e. not impacting fitness otherwise) differences in dispersal capacity. Using a trait-based metacommunity model along a warming climatic gradient the effect of three different dispersal scenarios on model predictions of diversity change were compared. Adding random variation in species dispersal capacity caused extinctions by the introduction of strong fitness differences due an inherent property of the dispersal kernel. Simulations including a fitness-equalising trade-off based on empirical relationships between seed mass (here affecting dispersal distance, establishment probability, and seedling biomass) and seed number (fecundity) maintained higher initial species diversity and predicted lower extinction risk and diversity loss during climate change than simulations with variable dispersal capacity. Large seeded species persisted during climate change, but developed lags behind their climate niche that may cause extinction debts. Small seeded species were more extinction-prone during climate change but tracked their niches through dispersal and colonisation, despite competitive resistance from residents. Life history trade-offs involved in coexistence

  6. NLOS UV Channel Modeling Using Numerical Integration and an Approximate Closed-Form Path Loss Model

    CERN Document Server

    Gupta, Ankit; Brandt-Pearce, Maïté

    2012-01-01

    In this paper we propose a simulation method using numerical integration, and develop a closed-form link loss model for physical layer channel characterization for non-line of sight (NLOS) ultraviolet (UV) communication systems. The impulse response of the channel is calculated by assuming both uniform and Gaussian profiles for transmitted beams and different geometries. The results are compared with previously published results. The accuracy of the integration approach is compared to the Monte Carlo simulation. Then the path loss using the simulation method and the suggested closed-form expression are presented for different link geometries. The accuracies are evaluated and compared to the results obtained using other methods.

  7. Hurricane Loss Estimation Models: Opportunities for Improving the State of the Art.

    Science.gov (United States)

    Watson, Charles C., Jr.; Johnson, Mark E.

    2004-11-01

    The results of hurricane loss models are used regularly for multibillion dollar decisions in the insurance and financial services industries. These models are proprietary, and this “black box” nature hinders analysis. The proprietary models produce a wide range of results, often producing loss costs that differ by a ratio of three to one or more. In a study for the state of North Carolina, 324 combinations of loss models were analyzed, based on a combination of nine wind models, four surface friction models, and nine damage models drawn from the published literature in insurance, engineering, and meteorology. These combinations were tested against reported losses from Hurricanes Hugo and Andrew as reported by a major insurance company, as well as storm total losses for additional storms. Annual loss costs were then computed using these 324 combinations of models for both North Carolina and Florida, and compared with publicly available proprietary model results in Florida. The wide range of resulting loss costs for open, scientifically defensible models that perform well against observed losses mirrors the wide range of loss costs computed by the proprietary models currently in use. This outcome may be discouraging for governmental and corporate decision makers relying on this data for policy and investment guidance (due to the high variability across model results), but it also provides guidance for the efforts of future investigations to improve loss models. Although hurricane loss models are true multidisciplinary efforts, involving meteorology, engineering, statistics, and actuarial sciences, the field of meteorology offers the most promising opportunities for improvement of the state of the art.

  8. Gross margin losses due to Salmonella Dublin infection in Danish dairy cattle herds estimated by simulation modelling

    DEFF Research Database (Denmark)

    Nielsen, Torben Dahl; Kudahl, Anne Braad; Østergaard, S.

    2013-01-01

    and dynamic simulation model. The model incorporated six age groups (neonatal, pre-weaned calves, weaned calves, growing heifers, breeding heifers and cows) and five infection stages (susceptible, acutely infected, carrier, super shedder and resistant). The effects of introducing one S. Dublin infectious...... losses. This was more influential in the poorer management scenarios due to increased number of infected cows. The results can be used to inform dairy farmers of the benefits of preventing introduction and controlling spread of S. Dublin. Furthermore, they can be used in cost-benefit analyses of control...

  9. An Incidence Loss Model for Wave Rotors with Axially Aligned Passages

    Science.gov (United States)

    Paxson, Daniel E.

    1998-01-01

    A simple mathematical model is described to account for the losses incurred when the flow in the duct (port) of a wave rotor is not aligned with the passages. The model, specifically for wave rotors with axially aligned passages, describes a loss mechanism which is sensitive to incident flow angle and Mach number. Implementation of the model in a one-dimensional CFD based wave rotor simulation is presented. Comparisons with limited experimental results are consistent with the model. Sensitivity studies are presented which highlight the significance of the incidence loss relative to other loss mechanisms in the wave rotor.

  10. Stellar energy loss rates in the pair-annihilation process beyond the standard model

    Science.gov (United States)

    Hernández-Ruíz, M. A.; Gutiérrez-Rodríguez, A.; González-Sánchez, A.

    2017-01-01

    We calculate the stellar energy loss due to neutrino-pair production in e+e- annihilation in the context of a 331 model, a left-right symmetric model and a simplest little Higgs model in a way that can be used in supernova calculations. We also present some simple estimates which show that such process can act as an efficient energy loss mechanism in the shocked supernova core. We find that the stellar energy loss is almost independent of the parameters of the models in the allowed range for these parameters. This work complements other studies on the stellar energy loss rate in e+e- annihilation.

  11. Modelling TF ripple loss of alpha particles in TFTR DT experiments

    Energy Technology Data Exchange (ETDEWEB)

    Redi, M.H.; Budny, R.V.; Darrow, D.S. [and others

    1995-07-01

    Modelling of TF ripple loss of alphas in DT experiments on TFTR now includes neoclassical calculations of first orbit loss, stochastic ripple diffusion, ripple trapping and collisional effects. A rapid way to simulate experiment has been developed which uses a simple stochastic domain model for TF ripple loss within the TRANSP analysis code, with the ripple diffusion threshold evaluated by comparison with more accurate but computationally expensive Hamiltonian coordinate guiding center code simulations. Typical TF collisional ripple loss predictions are 6-10% loss of alphas for TFTR D-T experiments at I{sub p} = 1.0-2.0 MA and R = 2.52 m.

  12. Influence of strand surface condition on interstrand contact resistance and coupling loss in NbTi-wound Rutherford cables

    CERN Document Server

    Sumption, M D; Scanlan, R M; Nijhuis, A; ten Kate, H H J; Kim, S W; Wake, M; Shintomi, T

    1999-01-01

    Presented in this work are the results of directly measured and AC- loss-derived interstrand contact resistance (ICR) measurements performed magnetically or resistively on bare-Cu and coated-strand pairs, calorimetrically on $9 11-strand Rutherford cables wound with strands that had been coated with various metallic and insulating layers, and calorimetrically and magnetically on 28-strand Rutherford cables (LHC-type) wound with bare-Cu-, Ni-, and $9 stabrite-plated strands. Comparisons are made of the effects of various conditions of heat treatment, HT (time and temperature), and pressure (applied during HT and then either maintained or re-applied during measurement). The $9 resulting ICRs are compared and interpreted in terms of the oxide layer on the strand coating and its response to curing conditions. (66 refs).

  13. A transgenic mutant of Lactuca sativa (lettuce) with a T-DNA tightly linked to loss of downy mildew resistance.

    Science.gov (United States)

    Okubara, P A; Arroyo-Garcia, R; Shen, K A; Mazier, M; Meyers, B C; Ochoa, O E; Kim, S; Yang, C H; Michelmore, R W

    1997-11-01

    One hundred and ninety-two independent primary transformants of lettuce cv. Diana were obtained by co-cultivation with Agrobacterium tumefaciens carrying constructs containing maize Ac transposase and Ds. R2 families were screened for mutations at four genes (Dm) for resistance to downy mildew. One family, designated dm3t524, had lost resistance to an isolate of Bremia lactucae expressing the avirulence gene Avr3. Loss of resistance segregated as a single recessive allele of Dm3. The mutation was not due to a large deletion as all molecular markers flanking Dm3 were present. Loss of Dm3 activity co-segregated with a T-DNA from which Ds had excised. Genomic DNA flanking the right border of this T-DNA was isolated by inverse polymerase chain reaction. This genomic sequence was present in four to five copies in wild-type cv. Diana. One copy was missing in all eight deletion mutants of Dm3 and altered in dm3t524, indicating tight physical linkage to Dm3. Three open reading frames (ORFs) occurred in a 6.6-kb region flanking the insertion site; however, expression of these ORFs was not detected. No similarities were detected between these ORFs and resistance genes cloned from other species. Transgenic complementation with 11-to 27-kb genomic fragments of Diana spanning the insertion site failed to restore Dm3 function to two ethyl methanesulfonate (EMS)-induced mutants of Dm3 or to cv. Cobham Green, which naturally lacks Dm3 activity. Therefore, either the T-DNA inserted extremely close to, but not within, Dm3 and the mutation may have been caused by secondary movement of Ds, or Dm3 activity is encoded by a gene extending beyond the fragments used for complementation.

  14. Change in Bone Mineral Density During Weight Loss with Resistance Versus Aerobic Exercise Training in Older Adults.

    Science.gov (United States)

    Beavers, Kristen M; Beavers, Daniel P; Martin, Sarah B; Marsh, Anthony P; Lyles, Mary F; Lenchik, Leon; Shapses, Sue A; Nicklas, Barbara J

    2017-04-03

    To examine the effect of exercise modality during weight loss on hip and spine bone mineral density (BMD) in overweight and obese, older adults. This analysis compared data from two 5-month, randomized controlled trials of caloric restriction (CR; inducing 5-10% weight loss) with either resistance training (RT) or aerobic training (AT) in overweight and obese, older adults. Participants in the RT + CR study underwent 3 days/week of 8 upper/lower body exercises (3 sets, 10 repetitions at 70% 1 RM) and participants in the AT+CR study underwent 4 days/week of treadmill walking (30 min at 65-70% heart rate reserve). BMD at the total hip, femoral neck, and lumbar spine was assessed via dual-energy X-ray absorptiometry at baseline and 5 months. A total of 123 adults (69.4 ± 3.5 years, 67% female, 81% Caucasian) participated in the RT+CR (n = 60) and AT+CR (n = 63) interventions. Average weight loss was 5.7% (95% CI: 4.6-6.7%) and 8.2% (95% CI: 7.2-9.3%) in RT+CR and AT+CR groups, respectively. After adjustment for age, gender, race, baseline BMI and BMD, and weight change, differential treatment effects were observed for total hip and femoral neck (both p resistance, rather than aerobic, training during CR may attenuate loss of hip and femoral neck BMD in overweight and obese older adults. Findings warrant replication from a long-term, adequately powered, RCT.

  15. Loss of NDG-4 extends lifespan and stress resistance in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Brejning, Jeanette; Nørgaard, Steffen; Schøler, Lone Vedel;

    2014-01-01

    NDG-4 is a predicted transmembrane acyltransferase protein that acts in the distribution of lipophilic factors. Consequently, ndg-4 mutants lay eggs with a pale appearance due to lack of yolk, and they are resistant to sterility caused by dietary supplementation with the long-chain omega-6 polyun...

  16. Exploring alternative wind vulnerability and loss modeling methods - application to Europe extra-tropical cyclones

    Science.gov (United States)

    Peiris, N.

    2009-04-01

    Catastrophe models are used to assess the economic and insured loss to the built environment due to natural hazards such as earthquakes, windstorms, floods, storm surges, tsunamis, etc. A conventional catastrophe model estimating direct economic loss could be divided into three basic components; hazard, vulnerability and exposure. For a single event, the hazard component represents the best estimate realization of the hazard footprint over a region at the modeling resolution, i.e. variable grid, postalcode, cresta, etc. The vulnerability component represents the response of the buildings or any modeled structure to the hazard, quantified in terms of a loss ratio. The exposure component represents the value of the buildings in a portfolio covering a region or those underwritten by an insurer or a re-insurer. The exposure together with the vulnerability functions produces the expected economic loss of the hazard footprint for a given hazard event. In the case of estimating indirect economic losses and insured losses financial models are utilized with various financial structures applied on the economic loss estimates. The commonly used method of characterizing wind vulnerability of buildings is to develop functions of mean loss ratio or mean damage ratio (MDR) vs wind speed where the wind speed is often defined as the peak gust measured at a height of 10m above the ground elevation. The uncertainty associated with MDR due to the likelihood of the building experiencing a range of damage states and hence loss ratios at a given wind speed is quantified by a continuous statistical distribution with a mean (which is the MDR) and a standard deviation, SD. For a given event footprint a conventional catastrophe model calculates an MDR and associated SD for each location of a building portfolio. This together with the location exposure or insured value results in the location loss. The location losses are then aggregated together with their SDs to obtain the total expected

  17. Modeling magnetized neutron stars using resistive MHD

    CERN Document Server

    Palenzuela, Carlos

    2013-01-01

    This work presents an implementation of the resistive MHD equations for a generic algebraic Ohm's law which includes the effects of finite resistivity within full General Relativity. The implementation naturally accounts for magnetic-field-induced anisotropies and, by adopting a phenomenological current, is able to accurately describe electromagnetic fields in the star and in its magnetosphere. We illustrate the application of this approach in interesting systems with astrophysical implications; the aligned rotator solution and the collapse of a magnetized rotating neutron star to a black hole.

  18. Insulin resistance and inflammation predict kinetic body weight changes in response to dietary weight loss and maintenance in overweight and obese subjects by using a Bayesian network approach.

    Science.gov (United States)

    Kong, Ling Chun; Wuillemin, Pierre-Henri; Bastard, Jean-Philippe; Sokolovska, Nataliya; Gougis, Sophie; Fellahi, Soraya; Darakhshan, Froogh; Bonnefont-Rousselot, Dominique; Bittar, Randa; Doré, Joël; Zucker, Jean-Daniel; Clément, Karine; Rizkalla, Salwa

    2013-12-01

    The ability to identify obese subjects who will lose weight in response to energy restriction is an important strategy in obesity treatment. We aimed to identify obese subjects who would lose weight and maintain weight loss through 6 wk of energy restriction and 6 wk of weight maintenance. Fifty obese or overweight subjects underwent a 6-wk energy-restricted, high-protein diet followed by another 6 wk of weight maintenance. Network modeling by using combined biological, gut microbiota, and environmental factors was performed to identify predictors of weight trajectories. On the basis of body weight trajectories, 3 subject clusters were identified. Clusters A and B lost more weight during energy restriction. During the stabilization phase, cluster A continued to lose weight, whereas cluster B remained stable. Cluster C lost less and rapidly regained weight during the stabilization period. At baseline, cluster C had the highest plasma insulin, interleukin (IL)-6, adipose tissue inflammation (HAM56+ cells), and Lactobacillus/Leuconostoc/Pediococcus numbers in fecal samples. Weight regain after energy restriction correlated positively with insulin resistance (homeostasis model assessment of insulin resistance: r = 0.5, P = 0.0002) and inflammatory markers (IL-6; r = 0.43, P = 0.002) at baseline. The Bayesian network identified plasma insulin, IL-6, leukocyte number, and adipose tissue (HAM56) at baseline as predictors that were sufficient to characterize the 3 clusters. The prediction accuracy reached 75.5%. The resistance to weight loss and proneness to weight regain could be predicted by the combination of high plasma insulin and inflammatory markers before dietary intervention.

  19. Correlations between flow resistance and geometry in a model of the human nose.

    Science.gov (United States)

    Schreck, S; Sullivan, K J; Ho, C M; Chang, H K

    1993-10-01

    The relationship between the pressure losses within the nasal airways and nasal geometry were studied in a 3:1 scale model. The geometry of the model was based on magnetic resonance images of the skull of a healthy male subject. Pressure measurements, flow visualization, and hot-wire anemometry studies were performed at flow rates that, in vivo, corresponded to flows of between 0.05 and 1.50 l/s. The influence of nasal congestion and the collapse of the external nares were examined by using modeling clay to simulate local constrictions in the cross section. A dimensionless analysis of the pressure losses within three sections of the airway revealed the influence of various anatomic dimensions on nasal resistance. The region of the exterior nose behaves as a contraction-expansion nozzle in which the pressure losses are a function of the smallest cross-sectional area. Losses in the interior nose resemble those associated with channel flow. The nasopharynx is modeled as a sharp bend in a circular duct. Good correspondence was found between the predicted and actual pressure losses in the model under conditions that stimulated local obstructions and congestion.

  20. Loss of NDG-4 extends lifespan and stress resistance in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Brejning, Jeanette; Nørgaard, Steffen; Schøler, Lone Vedel

    2014-01-01

    NDG-4 is a predicted transmembrane acyltransferase protein that acts in the distribution of lipophilic factors. Consequently, ndg-4 mutants lay eggs with a pale appearance due to lack of yolk, and they are resistant to sterility caused by dietary supplementation with the long-chain omega-6...... polyunsaturated fatty acid dihommogamma-linolenic acid (DGLA). Two other proteins, NRF-5 and NRF-6, a homolog of a mammalian secreted lipid binding protein and a NDG-4 homolog, respectively, have previously been shown to function in the same lipid transport pathway. Here, we report that mutation of the NDG-4...... hormone receptor NHR-80 (HNF4 homolog) is required for longevity in germline less animals. We find that NHR-80 is also required for longevity of ndg-4 mutants. Moreover, we find that nrf-5 and nrf-6 mutants also have extended lifespan and increased stress resistance, suggesting that altered lipid...

  1. Intrawire resistance, AC loss and strain dependence of critical current in MgB2 wires with and without cold high-pressure densification

    NARCIS (Netherlands)

    Zhou, C.; Gao, P.; Krooshoop, H.J.G.; Dhallé, M.M.J.; Sumption, M.D.; Rindfleisch, M.; Tomsic, M.; Küllich, M.; Senatore, C.; Nijhuis, A.

    2014-01-01

    The intrawire resistance and alternating current (AC) loss of two MgB2 wires with filaments surrounded by Nb barriers have been measured and analyzed. Relatively high values of filament-to-matrix contact resistivity are found in the MgB2 wires; the values are two or three orders higher than those co

  2. Hidden Hearing Loss and Computational Models of the Auditory Pathway: Predicting Speech Intelligibility Decline

    Science.gov (United States)

    2016-11-28

    Title: Hidden Hearing Loss and Computational Models of the Auditory Pathway: Predicting Speech Intelligibility Decline Christopher J. Smalt...to utilize computational models of the auditory periphery and auditory cortex to study the effect of low spontaneous rate ANF loss on the cortical...clinical hearing thresholds is difficulty in understanding speech in noise. Recent animal studies have shown that noise exposure causes selective loss

  3. Predicting Performance during Chronic Sleep Loss: Identification of Factors Sensitive to Individual Fatigue Resistance

    Science.gov (United States)

    2015-03-18

    confirmed that changes in response to sleep loss were evident, whereas significance at the individual level revealed inter-individual variability in...Repeated Measures Analyses of Variance (ANOVAs) to identify those variables which were significantly affected by chronic sleep restriction. Any...during the sleep restriction phase of the study. Psychomotor Vigilance Task (PVT). Two variables from the PVT were analyzed: number of PVT

  4. Sex Difference in Susceptibility and Resistance to Noise-Induced Hearing Loss in Chinchillas

    Science.gov (United States)

    2000-10-01

    depletion of cellular GSH can increase sensitivity to damage. In organ culture, cisplatin has been shown to increase Superoxide dismutase (SOD...individually non-traumatic could combine to produce substantial hearing loss and hair cell damage in chinchillas. If cisplatin depletes GSH and other...compound that increases GSH and GSH -peroxidase activity, significantly reduced threshold shifts in rats treated with cisplatin , and Ravi et al

  5. Frequency of intron loss correlates with processed pseudogene abundance: a novel strategy to test the reverse transcriptase model of intron loss

    Science.gov (United States)

    2013-01-01

    Background Although intron loss in evolution has been described, the mechanism involved is still unclear. Three models have been proposed, the reverse transcriptase (RT) model, genomic deletion model and double-strand-break repair model. The RT model, also termed mRNA-mediated intron loss, suggests that cDNA molecules reverse transcribed from spliced mRNA recombine with genomic DNA causing intron loss. Many studies have attempted to test this model based on its predictions, such as simultaneous loss of adjacent introns, 3'-side bias of intron loss, and germline expression of intron-lost genes. Evidence either supporting or opposing the model has been reported. The mechanism of intron loss proposed in the RT model shares the process of reverse transcription with the formation of processed pseudogenes. If the RT model is correct, genes that have produced more processed pseudogenes are more likely to undergo intron loss. Results In the present study, we observed that the frequency of intron loss is correlated with processed pseudogene abundance by analyzing a new dataset of intron loss obtained in mice and rats. Furthermore, we found that mRNA molecules of intron-lost genes are mostly translated on free cytoplasmic ribosomes, a feature shared by mRNA molecules of the parental genes of processed pseudogenes and long interspersed elements. This feature is likely convenient for intron-lost gene mRNA molecules to be reverse transcribed. Analyses of adjacent intron loss, 3'-side bias of intron loss, and germline expression of intron-lost genes also support the RT model. Conclusions Compared with previous evidence, the correlation between the abundance of processed pseudogenes and intron loss frequency more directly supports the RT model of intron loss. Exploring such a correlation is a new strategy to test the RT model in organisms with abundant processed pseudogenes. PMID:23497167

  6. Adaptations to a diet-based weight-reducing programme in obese women resistant to weight loss.

    Science.gov (United States)

    Tremblay, A; Lepage, C; Panahi, S; Couture, C; Drapeau, V

    2015-06-01

    The aim of this study was to assess energy intake, resting metabolic rate (RMR), appetite sensations, eating behaviours and sleep duration and quality in obese women resistant to body weight loss when subjected to a diet-based weight-reducing programme. A pooled cohort of obese women (n = 75; aged 39 ± 8 years; body mass index: 33 ± 4 kg m(-2)) participated in a 12-16-week diet-based weight loss programme targeting a daily energy deficit of 500-700 kcal d(-1). Women were classified in tertiles a posteriori based on the response of their body weight to dietary supervision (high, moderate and low responders). Post-intervention, mean weight loss was 3.3 ± 2.8 kg and explained by the 2.9 ± 2.6 kg reduction in fat mass. Mean weight loss was 6.2 ± 1.6, 3.4 ± 0.6 and 0.2 ± 1.4 kg in participants classified in the high, middle and low tertiles, respectively. Women in the low tertile reduced their daily energy intake and susceptibility to hunger during the programme to a lesser extent than those in the high tertile and had higher fasting hunger in response to the dietary intervention. Women in the high tertile maintained their RMR, which was in contrast to the significant decrease predicted by their weight loss. They also reported a significant improvement in sleep quality and an increase in sleep duration compared with other tertiles. The differences in the response of body weight to dietary supervision may be explained, in part, by variations in energy intake, eating behaviours, appetite sensations and sleep duration and quality. © 2015 World Obesity.

  7. Measurements of Epidural Space Depth Using Preexisting CT Scans Correlate with Loss of Resistance Depth during Thoracic Epidural Catheter Placement

    Directory of Open Access Journals (Sweden)

    Nathaniel H. Greene

    2015-01-01

    Full Text Available Background. Thoracic epidural catheters provide the best quality postoperative pain relief for major abdominal and thoracic surgical procedures, but placement is one of the most challenging procedures in the repertoire of an anesthesiologist. Most patients presenting for a procedure that would benefit from a thoracic epidural catheter have already had high resolution imaging that may be useful to assist placement of a catheter. Methods. This retrospective study used data from 168 patients to examine the association and predictive power of epidural-skin distance (ESD on computed tomography (CT to determine loss of resistance depth acquired during epidural placement. Additionally, the ability of anesthesiologists to measure this distance was compared to a radiologist, who specializes in spine imaging. Results. There was a strong association between CT measurement and loss of resistance depth (P35 changed this relationship (P=0.007. The ability of anesthesiologists to make CT measurements was similar to a gold standard radiologist (all individual ICCs>0.9. Conclusions. Overall, this study supports the examination of a recent CT scan to aid in the placement of a thoracic epidural catheter. Making use of these scans may lead to faster epidural placements, fewer accidental dural punctures, and better epidural blockade.

  8. Modeling Analysis and Improvement of Power Loss in Microgrid

    Directory of Open Access Journals (Sweden)

    H. Lan

    2015-01-01

    Full Text Available The consumption of conventional energy sources and environmental concerns have resulted in rapid growth in the amount of renewable energy introduced to power systems. With the help of distributed generations (DG, the improvement of power loss and voltage profile can be the salient benefits. However, studies show that improper placement and size of energy storage system (ESS lead to undesired power loss and the risk of voltage stability, especially in the case of high renewable energy penetration. To solve the problem, this paper sets up a microgrid based on IEEE 34-bus distribution system which consists of wind power generation system, photovoltaic generation system, diesel generation system, and energy storage system associated with various types of load. Furthermore, the particle swarm optimization (PSO algorithm is proposed in the paper to minimize the power loss and improve the system voltage profiles by optimally managing the different sorts of distributed generations under consideration of the worst condition of renewable energy production. The established IEEE 34-bus system is adopted to perform case studies. The detailed simulation results for each case clearly demonstrate the necessity of optimal management of the system operation and the effectiveness of the proposed method.

  9. SPICE modeling of memristors with multilevel resistance states

    Institute of Scientific and Technical Information of China (English)

    Fang Xu-Dong; Tang Yu-Hua; Wu Jun-Jie

    2012-01-01

    With CMOS technologies approaching the scaling ceiling,novel memory technologies have thrived in recent years,among which the memristor is a rather promising candidate for future resistive memory (RRAM).Memristor's potential to store multiple bits of information as different resistance levels allows its application in multilevel cell (MCL) technology,which can significantly increase the memory capacity.However,most existing memristor models are built for binary or continuous memristance switching.In this paper,we propose the simulation program with integrated circuits emphasis (SPICE) modeling of charge-controlled and flux-controlled memristors with multilevel resistance states based on the memristance versus state map.In our model,the memristance switches abruptly between neighboring resistance states.The proposed model allows users to easily set the number of the resistance levels as parameters,and provides the predictability of resistance switching time if the input current/voltage waveform is given.The functionality of our models has been validated in HSPICE.The models can be used in multilevel RRAM modeling as well as in artificial neural network simulations.

  10. Positive and normative modeling for Palmer amaranth control and herbicide resistance management.

    Science.gov (United States)

    Frisvold, George B; Bagavathiannan, Muthukumar V; Norsworthy, Jason K

    2017-06-01

    Dynamic optimization models are normative; they solve for what growers 'ought to do' to maximize some objective, such as long-run profits. While valuable for research, such models are difficult to solve computationally, limiting their applicability to grower resistance management education. While discussing properties of normative models in general, this study presents results of a specific positive model of herbicide resistance management, applied to Palmer amaranth control on a representative cotton farm. This positive model compares a proactive resistance management strategy to a reactive strategy with lower short-run costs, but greater risk of herbicide resistance developing. The proactive strategy can pay for itself within 1-4 years, with a yield advantage of 4% or less if the yield advantage begins within 1-2 years of adoption. Whether the proactive strategy is preferable is sensitive to resistance onset and yield losses, but less sensitive to cotton prices or baseline yields. Industry rebates to encourage residual herbicide use (to delay resistance to post-emergence treatments) may be too small to alter grower behavior or they may be paid to growers who would have used residuals anyway. Rebates change grower behavior over a relatively narrow range of model parameters. The size of rebates needed to induce a grower to adopt the proactive strategy declines significantly if growers extend their planning horizon from 1 year to 3-4 years. Whether proactive resistance management is more profitable than a reactive strategy is more sensitive to biological parameters than economic ones. Simulation results suggest growers with longer time horizons (perhaps younger ones) would be more responsive to rebate programs. More empirical work is needed to determine how much rebates increase residual use above what would occur without them. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  11. Mathematical modeling of the hormonal regulation of food intake and body weight : applications to caloric restriction and leptin resistance

    OpenAIRE

    Jacquier, Marine

    2016-01-01

    The regulation of food intake and energy expenditure usually limits important loss or gain of body weight. Hormones (leptin, ghrelin, insulin) and nutrients (glucose, triglycerides) are among the main regulators of food intake. Leptin is also involved in leptin resistance, often associated with obesity and characterized by a reduced efficacy to regulate food intake. Mathematical models describing the dynamics of body weight have been used to assist clinical weight loss interventions or to stu...

  12. The comparison of models for calculating heat conduction losses in laser cutting of metals

    Science.gov (United States)

    Galushkin, M. G.; Golubev, V. S.; Grishaev, R. V.; Khomenko, M. D.

    2011-02-01

    Numerical comparisons of some models for estimating the power losses due to heat conduction in process of gas-assisted laser cutting are presented in this paper. In spite of differences between these models their results match fairly well.

  13. Loss Performance Modeling for Hierarchical Heterogeneous Wireless Networks With Speed-Sensitive Call Admission Control

    DEFF Research Database (Denmark)

    Huang, Qian; Huang, Yue-Cai; Ko, King-Tim;

    2011-01-01

    dimensioning and planning. This paper investigates the computationally efficient loss performance modeling for multiservice in hierarchical heterogeneous wireless networks. A speed-sensitive call admission control (CAC) scheme is considered in our model to assign overflowed calls to appropriate tiers...

  14. Off-design performance loss model for radial turbines with pivoting, variable-area stators

    Science.gov (United States)

    Meitner, P. L.; Glassman, A. J.

    1980-01-01

    An off-design performance loss model was developed for variable stator (pivoted vane), radial turbines through analytical modeling and experimental data analysis. Stator loss is determined by a viscous loss model; stator vane end-clearance leakage effects are determined by a clearance flow model. Rotor loss coefficient were obtained by analyzing the experimental data from a turbine rotor previously tested with six stators having throat areas from 20 to 144 percent of design area and were correlated with stator-to-rotor throat area ratio. An incidence loss model was selected to obtain best agreement with experimental results. Predicted turbine performance is compared with experimental results for the design rotor as well as with results for extended and cutback versions of the rotor. Sample calculations were made to show the effects of stator vane end-clearance leakage.

  15. Modeling Truncated Loss Data of Operational Risk in E-banking

    Directory of Open Access Journals (Sweden)

    Maryam Pirouz

    2013-11-01

    Full Text Available Operational risk is an important risk component for financial institutions, especially in E-banking. Large amount of capital that are assigned to decrease this risk are evidence to this subject. One of the most important factors for modeling operational risk to estimate capital charge is loss data collections of banks. But sometimes for reasons like decreasing the costs, banks save only the losses above some determined thresholds at their database. For achieving accurate capital charge, this threshold should be considered in determining capital charge. This paper focuses on modeling truncated loss data above some given threshold. We discuss several statistical methods for modeling truncated data, and suggest the best one for modeling truncated loss data. We have tested our suggested model for some operational loss data samples. Our results indicate that our approach can be useful for increasing accuracy of estimating operational risk capital charge in E- banking.

  16. Peritoneal protein losses in children with steroid-resistant nephrotic syndrome on continuous-cycler peritoneal dialysis.

    Science.gov (United States)

    Kopanati, Sashikala; Baum, Michel; Quan, Albert

    2006-07-01

    Glomerular protein permeability rises in nephrotic syndrome and may result from the effect of an unidentified "circulating factor." The effect of this "circulating factor" on the permeability of other body membranes is unknown. In this study we examine the peritoneal membrane protein permeability in patients with nephrotic syndrome on chronic-cycler peritoneal dialysis. We conducted a retrospective study of peritoneal protein losses in the dialysate effluent of 60 pediatric peritoneal dialysis patients (ages 5.1-22 years) over a 6-year period (January 1997-December 2002). Nineteen patients had steroid-resistant nephrotic syndrome (SRNS), while 41 had other non-nephrotic etiologies of renal failure. Total and normalized peritoneal protein losses are higher in SRNS than in non-nephrotic patients (12,603+/-5,403 mg/day vs 4,475+/-469 mg/day, Ppermeability, was higher in SRNS patients (3.50+/-1.00% vs 0.68+/-0.06%, Pdialysis, dialysis prescription, numbers of peritonitis episodes, catheter replacements, or hospitalizations. In summary, these results demonstrate that peritoneal protein losses in patients with SRNS are twice as great as in those without nephrotic syndrome. These results are consistent with the systemic effect of a "circulating factor" in SRNS and underscore the importance of adequate protein intake in patients on peritoneal dialysis.

  17. Refractive Index and Wave Resistance of Homogeneous Plane Waves in Isotropic Media with Losses and Gain

    Science.gov (United States)

    Fisanov, V. V.

    2017-09-01

    Analytical expressions for complex values of the wave number, refractive index, and the characteristic wave impedance of homogeneous electromagnetic plane waves propagating in a linear, homogeneous, isotropic medium with losses and gain are derived. Formulas for determining the type of normal wave as a function of the values of the real and imaginary parts of the permittivity and permeability are obtained, and conditions for the appearance of positive and negative refraction at the interface of two isotropic media are indicated. In the approach applied here, the concept of a negative refractive index is not used.

  18. Modeling the Mechanical Consequences of Age-Related Trabecular Bone Loss by XFEM Simulation

    Science.gov (United States)

    Fan, Ruoxun; Zhang, Xianbin; Liu, Jun; Jia, Zhengbin; Zhu, Dong

    2016-01-01

    The elderly are more likely to suffer from fracture because of age-related trabecular bone loss. Different bone loss locations and patterns have different effects on bone mechanical properties. Extended finite element method (XFEM) can simulate fracture process and was suited to investigate the effects of bone loss on trabecular bone. Age-related bone loss is indicated by trabecular thinning and loss and may occur at low-strain locations or other random sites. Accordingly, several ideal normal and aged trabecular bone models were created based on different bone loss locations and patterns; then, fracture processes from crack initiation to complete failure of these models were observed by XFEM; finally, the effects of different locations and patterns on trabecular bone were compared. Results indicated that bone loss occurring at low-strain locations was more detrimental to trabecular bone than that occurring at other random sites; meanwhile, the decrease in bone strength caused by trabecular loss was higher than that caused by trabecular thinning, and the effects of vertical trabecular loss on mechanical properties were more severe than horizontal trabecular loss. This study provided a numerical method to simulate trabecular bone fracture and distinguished different effects of the possible occurrence of bone loss locations and patterns on trabecular bone. PMID:27403206

  19. A modeling framework for the evolution and spread of antibiotic resistance: literature review and model categorization.

    Science.gov (United States)

    Spicknall, Ian H; Foxman, Betsy; Marrs, Carl F; Eisenberg, Joseph N S

    2013-08-15

    Antibiotic-resistant infections complicate treatment and increase morbidity and mortality. Mathematical modeling has played an integral role in improving our understanding of antibiotic resistance. In these models, parameter sensitivity is often assessed, while model structure sensitivity is not. To examine the implications of this, we first reviewed the literature on antibiotic-resistance modeling published between 1993 and 2011. We then classified each article's model structure into one or more of 6 categories based on the assumptions made in those articles regarding within-host and population-level competition between antibiotic-sensitive and antibiotic-resistant strains. Each model category has different dynamic implications with respect to how antibiotic use affects resistance prevalence, and therefore each may produce different conclusions about optimal treatment protocols that minimize resistance. Thus, even if all parameter values are correctly estimated, inferences may be incorrect because of the incorrect selection of model structure. Our framework provides insight into model selection.

  20. Comparative Study of Path Loss Models in Different Environments

    Directory of Open Access Journals (Sweden)

    Tilotma Yadav,

    2011-04-01

    Full Text Available By using propagation path models to estimate the received signal level as a function of distance, it becomes possible to predict the SNR for a mobile communication system. Both theoretical andmeasurement-based propagation models indicate that average received signal power decreases logarithmically with distance. For comparative analysis we use Okumura’s model, Hata model, COST231 Extension to Hata model,ECEC-33 model,SUI model along with the practical data. Most of these models are based on a systematic interpretation of theoretical data service area like urban(Built-up city or largetown crowded with large buildings, suburban (having some obstacles near the mobile radio car, but still not very congested and rural (No obstacles like tall trees or buildings like farm-land, rice field, open fields in INDIA at 900MHz & 1800MHz frequency .

  1. Loss of the membrane anchor of the target receptor is a mechanism of bioinsecticide resistance.

    Science.gov (United States)

    Darboux, Isabelle; Pauchet, Yannick; Castella, Claude; Silva-Filha, Maria Helena; Nielsen-LeRoux, Christina; Charles, Jean-François; Pauron, David

    2002-04-30

    The mosquitocidal activity of Bacillus sphaericus is because of a binary toxin (Bin), which binds to Culex pipiens maltase 1 (Cpm1), an alpha-glucosidase present in the midgut of Culex pipiens larvae. In this work, we studied the molecular basis of the resistance to Bin developed by a strain (GEO) of C. pipiens. Immunohistochemical and in situ hybridization experiments showed that Cpm1 was undetectable in the midgut of GEO larvae, although the gene was correctly transcribed. The sequence of the cpm1(GEO) cDNA differs from the sequence we previously reported for a susceptible strain (cpm1(IP)) by seven mutations: six missense mutations and a mutation leading to the premature termination of translation. When produced in insect cells, Cpm1(IP) was attached to the membrane by a glycosylphosphatidylinositol (GPI). In contrast, the premature termination of translation of Cpm1(GEO) resulted in the targeting of the protein to the extracellular compartment because of truncation of the GPI-anchoring site. The interaction between Bin and Cpm1(GEO) and the enzyme activity of the receptor were not affected. Thus, Bin is not toxic to GEO larvae because it cannot interact with the midgut cell membrane, even though its receptor site is unaffected. This mechanism contrasts with other known resistance mechanisms in which point mutations decrease the affinity of binding between the receptor and the toxin.

  2. Estimating Quantile Families of Loss Distributions for Non-Life Insurance Modelling via L-Moments

    Directory of Open Access Journals (Sweden)

    Gareth W. Peters

    2016-05-01

    Full Text Available This paper discusses different classes of loss models in non-life insurance settings. It then overviews the class of Tukey transform loss models that have not yet been widely considered in non-life insurance modelling, but offer opportunities to produce flexible skewness and kurtosis features often required in loss modelling. In addition, these loss models admit explicit quantile specifications which make them directly relevant for quantile based risk measure calculations. We detail various parameterisations and sub-families of the Tukey transform based models, such as the g-and-h, g-and-k and g-and-j models, including their properties of relevance to loss modelling. One of the challenges that are amenable to practitioners when fitting such models is to perform robust estimation of the model parameters. In this paper we develop a novel, efficient, and robust procedure for estimating the parameters of this family of Tukey transform models, based on L-moments. It is shown to be more efficient than the current state of the art estimation methods for such families of loss models while being simple to implement for practical purposes.

  3. Preliminary Mathematical Model for Jet Fuel Exacerbated Noise-Induced Hearing Loss

    Science.gov (United States)

    2013-01-01

    hearing loss . Noise alone induces hearing loss due to loss of hair cells in the cochlea, associated with oxidative stress. Jet fuel toxicity in association with noise may be at least partially explained by increased free radical production and oxidative stress at the cellular level, resulting in hair cell dysfunction and loss. This project combines a physiologically-based pharmacokinetic (PBPK) model to describe jet fuel component concentrations in the cochlea with pharmacodynamic (PD) models of free radical formation in the cochlea by both noise and

  4. A Numerical Study of Water Loss Rate Distributions in MDCT-Based Human Airway Models.

    Science.gov (United States)

    Wu, Dan; Miyawaki, Shinjiro; Tawhai, Merryn H; Hoffman, Eric A; Lin, Ching-Long

    2015-11-01

    Both three-dimensional (3D) and one-dimensional (1D) computational fluid dynamics methods are applied to study regional water loss in three multi-detector row computed-tomography-based human airway models at the minute ventilations of 6, 15 and 30 L/min. The overall water losses predicted by both 3D and 1D models in the entire respiratory tract agree with available experimental measurements. However, 3D and 1D models reveal different regional water loss rate distributions due to the 3D secondary flows formed at bifurcations. The secondary flows cause local skewed temperature and humidity distributions on inspiration acting to elevate the local water loss rate; and the secondary flow at the carina tends to distribute more cold air to the lower lobes. As a result, the 3D model predicts that the water loss rate first increases with increasing airway generation, and then decreases as the air approaches saturation, while the 1D model predicts a monotonic decrease of water loss rate with increasing airway generation. Moreover, the 3D (or 1D) model predicts relatively higher water loss rates in lower (or upper) lobes. The regional water loss rate can be related to the non-dimensional wall shear stress (τ (*)) by the non-dimensional mass transfer coefficient (h 0 (*) ) as [Formula: see text].

  5. Effects of Diet Composition and Insulin Resistance Status on Plasma Lipid Levels in a Weight Loss Intervention in Women.

    Science.gov (United States)

    Le, Tran; Flatt, Shirley W; Natarajan, Loki; Pakiz, Bilge; Quintana, Elizabeth L; Heath, Dennis D; Rana, Brinda K; Rock, Cheryl L

    2016-01-25

    Optimal macronutrient distribution of weight loss diets has not been established. The distribution of energy from carbohydrate and fat has been observed to promote differential plasma lipid responses in previous weight loss studies, and insulin resistance status may interact with diet composition and affect weight loss and lipid responses. Overweight and obese women (n=245) were enrolled in a 1-year behavioral weight loss intervention and randomly assigned to 1 of 3 study groups: a lower fat (20% energy), higher carbohydrate (65% energy) diet; a lower carbohydrate (45% energy), higher fat (35% energy) diet; or a walnut-rich, higher fat (35% energy), lower carbohydrate (45% energy) diet. Blood samples and data available from 213 women at baseline and at 6 months were the focus of this analysis. Triglycerides, total cholesterol, and high- and low-density lipoprotein cholesterol were quantified and compared between and within groups. Triglycerides decreased in all study arms at 6 months (Pdiet increased high-density lipoprotein cholesterol more than either the lower fat or lower carbohydrate diet (Pdiet also reduced low-density lipoprotein cholesterol in insulin-sensitive women, whereas the lower fat diet reduced both total cholesterol and high-density lipoprotein cholesterol in insulin-sensitive women (Pdiet groups, although insulin-sensitive women lost more weight with a lower fat, higher carbohydrate diet versus a higher fat, lower carbohydrate diet. The walnut-rich, higher fat diet resulted in the most favorable changes in lipid levels. URL: http://www.clinicaltrials.gov. Unique identifier: NCT01424007. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  6. Loss of Oncostatin M Signaling in Adipocytes Induces Insulin Resistance and Adipose Tissue Inflammation in Vivo.

    Science.gov (United States)

    Elks, Carrie M; Zhao, Peng; Grant, Ryan W; Hang, Hardy; Bailey, Jennifer L; Burk, David H; McNulty, Margaret A; Mynatt, Randall L; Stephens, Jacqueline M

    2016-08-12

    Oncostatin M (OSM) is a multifunctional gp130 cytokine. Although OSM is produced in adipose tissue, it is not produced by adipocytes. OSM expression is significantly induced in adipose tissue from obese mice and humans. The OSM-specific receptor, OSM receptor β (OSMR), is expressed in adipocytes, but its function remains largely unknown. To better understand the effects of OSM in adipose tissue, we knocked down Osmr expression in adipocytes in vitro using siRNA. In vivo, we generated a mouse line lacking Osmr in adiponectin-expressing cells (OSMR(FKO) mice). The effects of OSM on gene expression were also assessed in vitro and in vivo OSM exerts proinflammatory effects on cultured adipocytes that are partially rescued by Osmr knockdown. Osm expression is significantly increased in adipose tissue T cells of high fat-fed mice. In addition, adipocyte Osmr expression is increased following high fat feeding. OSMR(FKO) mice exhibit increased insulin resistance and adipose tissue inflammation and have increased lean mass, femoral length, and bone volume. Also, OSMR(FKO) mice exhibit increased expression of Osm, the T cell markers Cd4 and Cd8, and the macrophage markers F4/80 and Cd11c Interestingly, the same proinflammatory genes induced by OSM in adipocytes are induced in the adipose tissue of the OSMR(FKO) mouse, suggesting that increased expression of proinflammatory genes in adipose tissue arises both from adipocytes and other cell types. These findings suggest that adipocyte OSMR signaling is involved in the regulation of adipose tissue homeostasis and that, in obesity, OSMR ablation may exacerbate insulin resistance by promoting adipose tissue inflammation.

  7. The AC loss evaluation of central solenoid model coil for CFETR

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yi, E-mail: shiyi@ipp.ac.cn; Wu, Yu; Hao, QiangWang; Liu, Bo; Yang, Yilin

    2016-06-15

    Highlights: • In this study, The AC loss of CFETR CSMC is calculated. • The main AC losses type and mechanics of CFETR CSMC are introduced, where the hysteresis and coupling loss of Nb{sub 3}Sn and NbTi coil are estimated. • The low frequency eddy current loss calculation of stainless steel structural components is carried out by ANSYS with 3-D separate model. • In the case of conductor joints, a 3-D ANSYS code is also used to obtain the eddy current losses for the metal components. - Abstract: The AC loss of Central Solenoid Model Coil (CSMC) of China Fusion Engineering Test Reactor (CFETR) is calculated in order to be able to determine the allowable excitation current shape in time with respect to the available cooling capacity at liquid helium temperature. Firstly, the structure and operation parameters of CFETR CSMC are summarized including the superconductor, conductor and magnetic field distribution characteristic. Secondly, the main AC losses type and mechanics of CFETR CSMC are introduced, where the hysteresis and coupling loss of Nb{sub 3}Sn and NbTi coil are estimated using of the model data and a calculation flux density distribution in the cross-section of model coil by ANSYS 2-D model. Thirdly, the low frequency eddy current loss calculation of stainless steel structural components is carried out by ANSYS/EMAG code with 3-D separately for tension rods, plates and beams model. The interaction between several components is not considered. In the case of conductor joints, a 3-D ANSYS code is also used with current force to obtain the eddy current losses for the metal components. Lastly, the individual loss components are summed up. The significant conclusions are made which can provide the valuable guidance for safe operation of CSMC.

  8. Modeling strength loss in wood by chemical composition. Part I, An individual component model for southern pine

    Science.gov (United States)

    J. E. Winandy; P. K. Lebow

    2001-01-01

    In this study, we develop models for predicting loss in bending strength of clear, straight-grained pine from changes in chemical composition. Although significant work needs to be done before truly universal predictive models are developed, a quantitative fundamental relationship between changes in chemical composition and strength loss for pine was demonstrated. In...

  9. Thermodynamic and kinetic modelling: creep resistant materials

    DEFF Research Database (Denmark)

    Hald, John; Korcakova, L.; Danielsen, Hilmar Kjartansson

    2008-01-01

    particles and coarsening of MX, M23C6 and Laves phase particles. The modelling provided new insight into the long term stability of new steels. Modelling of the detrimental precipitation of Z phase Cr(V,Nb)N is described, which points to new approaches in alloy development for higher temperatures......The use of thermodynamic and kinetic modelling of microstructure evolution in materials exposed to high temperatures in power plants is demonstrated with two examples. Precipitate stability in martensitic 9–12%Cr steels is modelled including equilibrium phase stability, growth of Laves phase...

  10. Testing and Modeling of Machine Properties in Resistance Welding

    DEFF Research Database (Denmark)

    Wu, Pei

    electrode force, and the time of stabilizing does not depend on the level of the force. An additional spring mounted in the welding head improves the machine touching behavior due to a soft electrode application, but this results in longer time of oscillation of the electrode force, especially when......The objective of this work has been to test and model the machine properties including the mechanical properties and the electrical properties in resistance welding. The results are used to simulate the welding process more accurately. The state of the art in testing and modeling machine properties...... in resistance welding has been described based on a comprehensive literature study. The present thesis has been subdivided into two parts: Part I: Mechanical properties of resistance welding machines. Part II: Electrical properties of resistance welding machines. In part I, the electrode force in the squeeze...

  11. Complete Loss and Thermal Model of Power Semiconductors Including Device Rating Information

    DEFF Research Database (Denmark)

    Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon;

    2015-01-01

    loading but also the device rating as input variables. The quantified correlation between the power loss, thermal impedance and silicon area of Insulated Gate Bipolar Transistor (IGBT) is mathematically established. By this new modeling approach, all factors that have impacts to the loss and thermal......Thermal loading of power devices are closely related to the reliability performance of the whole converter system. The electrical loading and device rating are both important factors that determine the loss and thermal behaviors of power semiconductor devices. In the existing loss and thermal...... models, only the electrical loadings are focused and treated as design variables, while the device rating is normally pre-defined by experience with limited design flexibility. Consequently, a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical...

  12. Loss and thermal model for power semiconductors including device rating information

    DEFF Research Database (Denmark)

    Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon;

    2014-01-01

    The electrical loading and device rating are both important factors that determine the loss and thermal behaviors of power semiconductor devices. In the existing loss and thermal models, only the electrical loadings are focused and treated as design variables, while the device rating is normally...... pre-defined by experience with poor design flexibility. Consequently a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical loading but also the device rating as input variables. The quantified correlation between the power loss, thermal...... impedance and silicon area of Insulated Gate Bipolar Transistor (IGBT) is mathematically established. By this new modeling approach, all factors that have impacts to the loss and thermal profiles of power devices can be accurately mapped, enabling more design freedom to optimize the efficiency and thermal...

  13. Loss and thermal model for power semiconductors including device rating information

    DEFF Research Database (Denmark)

    Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon

    2014-01-01

    impedance and silicon area of Insulated Gate Bipolar Transistor (IGBT) is mathematically established. By this new modeling approach, all factors that have impacts to the loss and thermal profiles of power devices can be accurately mapped, enabling more design freedom to optimize the efficiency and thermal......The electrical loading and device rating are both important factors that determine the loss and thermal behaviors of power semiconductor devices. In the existing loss and thermal models, only the electrical loadings are focused and treated as design variables, while the device rating is normally...... pre-defined by experience with poor design flexibility. Consequently a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical loading but also the device rating as input variables. The quantified correlation between the power loss, thermal...

  14. Modeling evolution of insect resistance to genetically modified crops

    OpenAIRE

    2015-01-01

    Genetically modified crops producing insecticidal proteins from Bacillus thuringiensis (Bt) for insect control have been planted on more than 200 million ha worldwide since 1996 [1]. Evolution of resistance by insect pests threatens the continued success of Bt crops [2, 3]. To delay pest resistance, refuges of non-Bt crops are planted near Bt crops to allow survival of susceptible pests [4, 5]. We used computer simulations of a population genetic model to determine if predictions from the the...

  15. Treatment Resistant Depression with Loss of Antidepressant Response: Rapid—Acting Antidepressant Action of Dextromethorphan, A Possible Treatment Bridging Molecule

    Science.gov (United States)

    Lauterbach, Edward C.

    2016-01-01

    Dextromethorphan (DM) may have ketamine—like rapid—acting, treatment—resistant, and conventional antidepressant effects.1,2 This reports our initial experience with DM in unipolar Major Depressive Disorder (MDD). A patient with treatment—resistant MDD (failing adequate trials of citalopram and vortioxetine) with loss of antidepressant response (to fluoxetine and bupropion) twice experienced a rapid—acting antidepressant effect within 48 hours of DM administration and lasting 7 days, sustained up to 20 days with daily administration, then gradually developing labile loss of antidepressant response over the ensuing 7 days. Upon full relapse in DSM-5 MDD while taking 600 mg/day of the strong CYP2D6 inhibitor bupropion XL, a 300 mg oral loading dose of DM was given, followed by 60 mg po bid after an additional dose—finding period, without side effects. DM exhibited a ketamine—like rapid—acting antidepressant effect, thought to be mediated by mTOR activation (related to NMDA PCP site antagonism, sigma-1 and beta adrenergic receptor stimulation) and 5HTT inhibition, resulting in AMPA receptor trafficking, and dendritogenesis, spinogenesis, synaptogenesis, and increased neuronal survival (related to NMDA antagonism and sigma-1 and mTOR signaling). This report appears to be the first report of a rapid—acting effect in unipolar MDD and adds to antidepressant effects observed in the retrospective chart review of 77 patients with Bipolar II Disorder (Kelly and Lieberman 2014). If replicated, there is some reason to think that the administration of other agents with DM, such as lithium or D-cycloserine, might prolong the duration of the rapid-antidepressant effect. PMID:27738380

  16. Mathematical Modeling of Contact Resistance in Silicon Photovoltaic Cells

    KAUST Repository

    Black, J. P.

    2013-10-22

    In screen-printed silicon-crystalline solar cells, the contact resistance of a thin interfacial glass layer between the silicon and the silver electrode plays a limiting role for electron transport. We analyze a simple model for electron transport across this layer, based on the driftdiffusion equations. We utilize the size of the current/Debye length to conduct asymptotic techniques to simplify the model; we solve the model numerically to find that the effective contact resistance may be a monotonic increasing, monotonic decreasing, or nonmonotonic function of the electron flux, depending on the values of the physical parameters. © 2013 Society for Industrial and Applied Mathematics.

  17. A Particle Resistance Model for Flow through Porous Media

    Institute of Scientific and Technical Information of China (English)

    WU Jin-Sui; YIN Shang-Xian; ZHAO Dong-Yu

    2009-01-01

    A particle model for resistance of flow in isotropic porous media is developed based on the fractal geometry theory and on the drag force flowing around sphere.The proposed model is expressed as a function of porosity,fluid property,particle size,fluid velocity (or Reynolds number) and fractal characters Df of particles in porous media.The model predictions are in good agreement with the experimental data.The validity of the proposed model is thus verified.

  18. Information Loss Caused by Noise in Models for Dichotomous Items.

    Science.gov (United States)

    1982-11-29

    University of Tennessee, Knoxville, Tennessee. Those who worked for her as assistants include Paul S. Changas, Charles T. McCarter, Christina C. Grey... Lazarsfeld , 1959) and the constant information model (Samejima, RR-79-1), belong t " Type A Note that in the former two models the interval (6, 5...ability. In F. M. Lord and M. R. Novick; Statistical theories of mental test scores. Addison-Wesley, 1968, Chapters - 17-20. * [2] Lazarsfeld , P. F. Latent

  19. Location-based Mobile Relay Selection and Impact of Inaccurate Path Loss Model Parameters

    DEFF Research Database (Denmark)

    Nielsen, Jimmy Jessen; Madsen, Tatiana Kozlova; Schwefel, Hans-Peter

    2010-01-01

    In this paper we propose a relay selection scheme which uses collected location information together with a path loss model for relay selection, and analyze the performance impact of mobility and different error causes on this scheme. Performance is evaluated in terms of bit error rate...... in these situations. As the location-based scheme relies on a path loss model to estimate link qualities and select relays, the sensitivity with respect to inaccurate estimates of the unknown path loss model parameters is investigated. The parameter ranges that result in useful performance were found...

  20. Power Loss Calculation and Thermal Modelling for a Three Phase Inverter Drive System

    Directory of Open Access Journals (Sweden)

    Z. Zhou

    2005-12-01

    Full Text Available Power losses calculation and thermal modelling for a three-phase inverter power system is presented in this paper. Aiming a long real time thermal simulation, an accurate average power losses calculation based on PWM reconstruction technique is proposed. For carrying out the thermal simulation, a compact thermal model for a three-phase inverter power module is built. The thermal interference of adjacent heat sources is analysed using 3D thermal simulation. The proposed model can provide accurate power losses with a large simulation time-step and suitable for a long real time thermal simulation for a three phase inverter drive system for hybrid vehicle applications.

  1. Comparison of radiative energy loss models in a hot QCD medium

    NARCIS (Netherlands)

    Verweij, M.

    2010-01-01

    The suppression of high $p_{T}$ hadron production in heavy ion collisions is thought to be due to energy loss by gluon radiation off hard partons in a QCD medium. Existing models of QCD radiative energy loss in a color-charged medium give estimates of the coupling strength of the parton to the

  2. A Simplified Model to Calculate AC Losses in Large 2G HTS Coils

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Jensen, Bogi Bech;

    2015-01-01

    AC losses are of great significance to quantify the performance of high temperature superconducting (HTS) devices. This paper presents a simplified model to calculate AC losses in large 2G HTS coils, which serves as a baseline to study HTS large scale applications such as electric machines. The m...

  3. Comparison of radiative energy loss models in a hot QCD medium

    NARCIS (Netherlands)

    Verweij, M.

    2010-01-01

    The suppression of high $p_{T}$ hadron production in heavy ion collisions is thought to be due to energy loss by gluon radiation off hard partons in a QCD medium. Existing models of QCD radiative energy loss in a color-charged medium give estimates of the coupling strength of the parton to the mediu

  4. Higher order saddlepoint approximations in the Vasicek portfolio credit loss model

    NARCIS (Netherlands)

    Huang, X.; Oosterlee, C.W.; van der Weide, J.A.M.

    2006-01-01

    This paper utilizes the saddlepoint approximation as an efficient tool to estimate the portfolio credit loss distribution in the Vasicek model. Value at Risk (VaR), the risk measure chosen in the Basel II Accord for the evaluation of capital requirement, can then be found by inverting the loss

  5. Sense-Making, Grief, and the Experience of Violent Loss: Toward a Mediational Model

    Science.gov (United States)

    Currier, Joseph M.; Holland, Jason M.; Neimeyer, Robert A.

    2006-01-01

    Bereavement following violent loss by accident, homicide or suicide increases the risk for complications in grieving. This is the first study to examine a constructivist model of grief that proposes that sense-making, or the capacity to construct an understanding of the loss experience, mediates the association between violent death and…

  6. Airflow resistivity of models of fibrous acoustic materials

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1996-01-01

    for the resistivity are given, which are valid for the cylinder (fiber) concentrations found in acoustic materials. A one-dimensional model consisting of parallel plates with random spacing between the plates is first discussed. Then a two-dimensional model consisting of parallel cylinders randomly spaced is treated...

  7. Behavior of an improved Zr fuel cladding with oxidation resistant coating under loss-of-coolant accident conditions

    Science.gov (United States)

    Park, Dong Jun; Kim, Hyun Gil; Jung, Yang Il; Park, Jung Hwan; Yang, Jae Ho; Koo, Yang Hyun

    2016-12-01

    This study investigates protective coatings for improving the high temperature oxidation resistance of Zr fuel claddings for light water nuclear reactors. FeCrAl alloy and Cr layers were deposited onto Zr plates and tubes using cold spraying. For the FeCrAl/Zr system, a Mo layer was introduced between the FeCrAl coating and the Zr matrix to prevent inter-diffusion at high temperatures. Both the FeCrAl and Cr coatings improved the oxidation resistance compared to that of the uncoated Zr alloy when exposed to a steam environment at 1200 °C. The ballooning behavior and mechanical properties of the coated cladding samples were studied under simulated loss-of-coolant accident conditions. The coated samples showed higher burst temperatures, lower circumferential strain, and smaller rupture openings compared to the uncoated Zr. Although 4-point bend tests of the coated samples showed a small increase in the maximum load, ring compression tests of a sectioned sample showed increased ductility.

  8. Modelling measurement microphones using BEM with visco-thermal losses

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Juhl, Peter Møller

    2012-01-01

    For many decades, models that can explain the behaviour of measurement condenser microphones have been proposed in the literature. These devices have an apparently simple working principle, a charged capacitor whose charge varies when one of its electrodes, the diaphragm, moves as a result of sound...... waves. However, measurement microphones must be manufactured very carefully due to their sensitivity to small changes of their physical parameters. There are different elements in a microphone, the diaphragm, the gap behind it, a back cavity, a vent for pressure equalization and an external medium. All...... these subsystems form a strongly coupled device that cannot be modelled properly as a superposition of submodels, but rather as a whole. For this reason, the challenge of microphone modelling is still an ongoing area of research. In this work, a newly developed Boundary Element Method implementation that includes...

  9. Structure of the scientific community modelling the evolution of resistance.

    Science.gov (United States)

    2007-12-05

    Faced with the recurrent evolution of resistance to pesticides and drugs, the scientific community has developed theoretical models aimed at identifying the main factors of this evolution and predicting the efficiency of resistance management strategies. The evolutionary forces considered by these models are generally similar for viruses, bacteria, fungi, plants or arthropods facing drugs or pesticides, so interaction between scientists working on different biological organisms would be expected. We tested this by analysing co-authorship and co-citation networks using a database of 187 articles published from 1977 to 2006 concerning models of resistance evolution to all major classes of pesticides and drugs. These analyses identified two main groups. One group, led by ecologists or agronomists, is interested in agricultural crop or stock pests and diseases. It mainly uses a population genetics approach to model the evolution of resistance to insecticidal proteins, insecticides, herbicides, antihelminthic drugs and miticides. By contrast, the other group, led by medical scientists, is interested in human parasites and mostly uses epidemiological models to study the evolution of resistance to antibiotic and antiviral drugs. Our analyses suggested that there is also a small scientific group focusing on resistance to antimalaria drugs, and which is only poorly connected with the two larger groups. The analysis of cited references indicates that each of the two large communities publishes its research in a different set of literature and has its own keystone references: citations with a large impact in one group are almost never cited by the other. We fear the lack of exchange between the two communities might slow progress concerning resistance evolution which is currently a major issue for society.

  10. Myricetin Prevents Alveolar Bone Loss in an Experimental Ovariectomized Mouse Model of Periodontitis.

    Science.gov (United States)

    Huang, Jialiang; Wu, Chuanlong; Tian, Bo; Zhou, Xiao; Ma, Nian; Qian, Yufen

    2016-03-22

    Periodontitis is a common chronic inflammatory disease, which leads to alveolar bone resorption. Healthy and functional alveolar bone, which can support the teeth and enable their movement, is very important for orthodontic treatment. Myricetin inhibited osteoclastogenesis by suppressing the expression of some genes, signaling pathways, and cytokines. This study aimed to investigate the effects of myricetin on alveolar bone loss in an ovariectomized (OVX) mouse model of periodontitis as well as in vitro osteoclast formation and bone resorption. Twenty-four healthy eight-week-old C57BL/J6 female mice were assigned randomly to four groups: phosphate-buffered saline (PBS) control (sham) OVX + ligature + PBS (vehicle), and OVX + ligature + low or high (2 or 5 mg∙kg(-1)∙day(-1), respectively) doses of myricetin. Myricetin or PBS was injected intraperitoneally (i.p.) every other day for 30 days. The maxillae were collected and subjected to further examination, including micro-computed tomography (micro-CT), hematoxylin and eosin (H&E) staining, and tartrate-resistant acid phosphatase (TRAP) staining; a resorption pit assay was also performed in vitro to evaluate the effects of myricetin on receptor activator of nuclear factor κ-B ligand (RANKL)-induced osteoclastogenesis. Myricetin, at both high and low doses, prevented alveolar bone resorption and increased alveolar crest height in the mouse model and inhibited osteoclast formation and bone resorption in vitro. However, myricetin was more effective at high dose than at low dose. Our study demonstrated that myricetin had a positive effect on alveolar bone resorption in an OVX mouse model of periodontitis and, therefore, may be a potential agent for the treatment of periodontitis and osteoporosis.

  11. Myricetin Prevents Alveolar Bone Loss in an Experimental Ovariectomized Mouse Model of Periodontitis

    Directory of Open Access Journals (Sweden)

    Jialiang Huang

    2016-03-01

    Full Text Available Periodontitis is a common chronic inflammatory disease, which leads to alveolar bone resorption. Healthy and functional alveolar bone, which can support the teeth and enable their movement, is very important for orthodontic treatment. Myricetin inhibited osteoclastogenesis by suppressing the expression of some genes, signaling pathways, and cytokines. This study aimed to investigate the effects of myricetin on alveolar bone loss in an ovariectomized (OVX mouse model of periodontitis as well as in vitro osteoclast formation and bone resorption. Twenty-four healthy eight-week-old C57BL/J6 female mice were assigned randomly to four groups: phosphate-buffered saline (PBS control (sham OVX + ligature + PBS (vehicle, and OVX + ligature + low or high (2 or 5 mg∙kg−1∙day−1, respectively doses of myricetin. Myricetin or PBS was injected intraperitoneally (i.p. every other day for 30 days. The maxillae were collected and subjected to further examination, including micro-computed tomography (micro-CT, hematoxylin and eosin (H&E staining, and tartrate-resistant acid phosphatase (TRAP staining; a resorption pit assay was also performed in vitro to evaluate the effects of myricetin on receptor activator of nuclear factor κ-B ligand (RANKL-induced osteoclastogenesis. Myricetin, at both high and low doses, prevented alveolar bone resorption and increased alveolar crest height in the mouse model and inhibited osteoclast formation and bone resorption in vitro. However, myricetin was more effective at high dose than at low dose. Our study demonstrated that myricetin had a positive effect on alveolar bone resorption in an OVX mouse model of periodontitis and, therefore, may be a potential agent for the treatment of periodontitis and osteoporosis.

  12. Modelling economic losses of historic and present-day high-impact winter windstorms in Switzerland

    Directory of Open Access Journals (Sweden)

    Christoph Welker

    2016-03-01

    Full Text Available This study investigates the wind gusts and associated economic loss patterns of high-impact winter windstorms in Switzerland between 1871 and 2011. A novel approach for simulating windstorm-related gusts and losses at regional to local scales is applied to a sample of 84 windstorms. The approach involves the dynamical downscaling of the Twentieth Century Reanalysis (20CR ensemble mean to 3-km horizontal grid size using the Weather Research and Forecasting (WRF model. Economic losses are simulated at municipal level for present-day asset distribution based on the downscaled (parameterised wind gusts at high spatiotemporal resolution using the open-source impact model climada. A comparison with insurance loss data for two recent windstorms (“Lothar” in 1999, “Joachim” in 2011 indicates that the loss simulation allows to realistically simulate the spatial patterns of windstorm losses. The loss amplitude is strongly underestimated for ‘Lothar’, while it is in reasonable agreement for ‘Joachim’. Possible reasons are discussed. Uncertainties concerning the loss simulation arise from the wind gust estimation method applied; estimates can differ considerably among the different methods, in particular over high orography. Furthermore, the quality of the loss simulation is affected by the underlying simplified assumptions regarding the distribution of assets and their susceptibilities to damage. For the whole windstorm sample, composite averages of simulated wind gust speed and loss are computed. Both composites reveal high values for the densely populated Swiss Plateau and lower values for south-eastern Switzerland; metropolitan areas stand out in the loss composite. Eight of the top 10 events concerning the losses simulated for present-day asset distribution and summed over all Swiss municipalities occurred after 1950. It remains uncertain whether this is due to decadal-scale changes of winter windstorms in Switzerland or merely due to a

  13. A New Decision Model for Reducing Trim Loss and Inventory in the Paper Industry

    National Research Council Canada - National Science Library

    Wang, Fu-Kwun; Liu, Feng-Tai

    2014-01-01

    .... To ensure that the results better suit the actual requirements, we present a new decision model based on the adjustment of scheduling and limitation of inventory quantity to differentiate trim loss...

  14. Flood Loss Models and Risk Analysis for Private Households in Can Tho City, Vietnam

    National Research Council Canada - National Science Library

    Do Thi Chinh; Nguyen Viet Dung; Animesh K Gain; Heidi Kreibich

    2017-01-01

    .... To improve flood risk analyses for Vietnam, this study presents novel multi-variable flood loss models for residential buildings and contents and demonstrates their application in a flood risk...

  15. RELAP5 Model Description and Validation for the BR2 Loss-of-Flow Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Licht, J. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Dionne, B. [Argonne National Lab. (ANL), Argonne, IL (United States); Van den Branden, G. [Argonne National Lab. (ANL), Argonne, IL (United States); Sikik, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Koonen, E. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-07-01

    This paper presents a description of the RELAP5 model, the calibration method used to obtain the minor loss coefficients from the available hydraulic data and the LOFA simulation results compared to the 1963 experimental tests for HEU fuel.

  16. Stellar energy loss rates in the pair-annihilation process beyond the standard model

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Ruiz, M.A. [Universidad Autonoma de Zacatecas, Unidad Academica de Ciencias Quimicas, Apartado Postal C-585, Zacatecas (Mexico); Gutierrez-Rodriguez, A. [Universidad Autonoma de Zacatecas, Facultad de Fisica, Apartado Postal C-580, Zacatecas (Mexico); Gonzalez-Sanchez, A. [Universidad Autonoma de Zacatecas, Facultad de Fisica, Apartado Postal C-580, Zacatecas (Mexico); PSL Research University, Observatoire de Paris, LERMA, CNRS UMR 8112, Paris (France)

    2017-01-15

    We calculate the stellar energy loss due to neutrino-pair production in e{sup +}e{sup -} annihilation in the context of a 331 model, a left-right symmetric model and a simplest little Higgs model in a way that can be used in supernova calculations. We also present some simple estimates which show that such process can act as an efficient energy loss mechanism in the shocked supernova core. We find that the stellar energy loss is almost independent of the parameters of the models in the allowed range for these parameters. This work complements other studies on the stellar energy loss rate in e{sup +}e{sup -} annihilation. (orig.)

  17. Model for collisional fast ion diffusion into Tokamak Fusion Test Reactor loss cone

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.S. [New York Univ., NY (United States). Courant Inst. of Mathematical Sciences]|[Korea Advanced Inst. of Science and Technology, Seoul (Korea, Republic of); Zweben, S.J.; Schivell, J.; Budny, R.; Scott, S. [Princeton Univ., NJ (United States). Plasma Physics Lab.

    1994-08-01

    An analytic model is developed to estimate the classical pitch angle scattering loss of energetic fusion product ions into prompt loss orbits in a tokamak geometry. The result is applied to alpha particles produced by deutrium-tritium fusion reactions in a plasma condition relevant to Tokamak Fusion Test Reactor (TFTR). A poloidal angular distribution of collisional fast ion loss at the first wall is obtained and the numerical result from the TRANSP code is discussed. The present model includes the effect that the prompt loss boundary moves away from the slowing-down path due to reduction in banana thickness, which enables us to understand, for the first time. the dependence of the collisional loss rate on Z{sub eff}.

  18. Monetary Shocks in a Model with Loss of Skills

    OpenAIRE

    Esteban-Pretel; Elisa, Faraglia

    2005-01-01

    Unemployment shows persistent and long lasting responses to nominal and real shocks. Standard real business cycle models with search frictions but homogeneous labor force are able to generate some persistence, but not enough to match the empirical evidence. Moreover, empirical studies emphasize the importance of the heterogeneity of the unemployment pool to fully understand unemployment dynamics. In particular, in most European countries the incidence of long term unemployment is big and well...

  19. Managing anthelmintic resistance in Parascaris spp.: A modelling exercise.

    Science.gov (United States)

    Leathwick, Dave M; Sauermann, Christian W; Geurden, Thomas; Nielsen, Martin K

    2017-06-15

    A previously described model for the dynamics of the parasitic stages of Parascaris spp. was modified to include eggs outside the host and the genetics of anthelmintic resistance before being used to address questions regarding the development of resistance. Three broad questions were addressed; i) How sustainable is the current common practice of treating foals monthly for their first year of life (i.e. 12 treatments/year)? ii) Does the timing of treatments have an effect on resistance development? (i.e. do certain treatments select for resistance more strongly than others?), and iii) How sustainable is the currently recommended strategy of targeting ascarid infections in foals with two treatments applied during the first five months of life? A range of variations within these broad questions were considered, such as the value in rotational deworming, whether larvicidal treatments are more selective for resistance, and whether combination anthelmintics should be introduced. Twelve anthelmintic treatments at monthly intervals resulted in the development of resistance to all the anthelmintics used, regardless of how they were used, indicating that such intensive treatment frequency is unlikely to be sustainable. The timing of a single annual treatment influenced resistance development with treatments at 3 and 4 months of age being more selective than treatments at other times. Treatments administered to foals older than 6 months of age did not select for resistance within the timeframe of these simulations. Treatments with activity against migrating third stage larvae (ivermectin and a programme of 5 daily treatments with fenbendazole) were more selective for resistance than those which only killed worms in the intestine. Restricting the number of treatments to young foals to two, administered at 2 and 5 months of age slowed the development of resistance by allowing a small contribution from susceptible genotype worms to subsequent generations. If the interval

  20. Path Loss Channel Model for Inland River Radio Propagation at 1.4 GHz

    Directory of Open Access Journals (Sweden)

    Junyi Yu

    2017-01-01

    Full Text Available In this paper, a propagation path loss model for inland river is proposed by three improvements compared with the Round Earth Loss (REL model for open-sea environment. Specifically, parameters optimization uses Okumura-Hata model in dB scale to replace the equation transformed from the free space loss in REL model; secondly, diffraction loss caused by the obstacles (e.g., large buildings, bridges, or some other facilities near the river bank is also taken into account; mixed-path methodology as another improvement is used for Inland River (IR model because the actual propagation environment between transmitter (TX antenna and receiver (RX antenna contains both land part and water part. The paper presents a set of 1.4 GHz measurements conducted along the Yangtze River in Wuhan. According to the comparison between path loss models and experimental results, IR model shows a good matching degree. After that, Root Mean Square Error (RMSE, Grey Relation Grade and Mean Absolute Percentage Error (GRG-MAPE, Pearson Correlation Coefficient, and Mean Absolute Percentage Error (PCC-MAPE are employed to implement quantitative analysis. The results prove that IR model with consideration of mixed path and deterministic information is more accurate than other classic empirical propagation models for these scenarios.

  1. Loss of Mbd2 Protects Mice Against High-Fat Diet-Induced Obesity and Insulin Resistance by Regulating the Homeostasis of Energy Storage and Expenditure.

    Science.gov (United States)

    Cheng, Jia; Song, Jia; He, Xiaoyu; Zhang, Meng; Hu, Shuang; Zhang, Shu; Yu, Qilin; Yang, Ping; Xiong, Fei; Wang, Dao Wen; Zhou, Jianfeng; Ning, Qin; Chen, Zhishui; Eizirik, Decio L; Zhou, Zhiguang; Zhao, Chunxia; Wang, Cong-Yi

    2016-11-01

    Previous studies including ours demonstrated that methyl-CpG-binding domain 2 (MBD2) acts as a reader to decipher DNA methylome-encoded information. We thus in the current study used Mbd2(-/-) mice as a model to dissect the impact of high-fat diet (HFD) on DNA methylome relevant to the pathoetiology of obesity. It was interestingly noted that mice deficient in Mbd2 were protected from HFD-induced obesity and insulin resistance. Mechanistic study revealed that HFD rendered epididymal adipose tissues to undergo a DNA methylation turnover as evidenced by the changes of methylation levels and patterns. Specifically, HFD was noted with higher potency to induce DNA hypomethylation in genes relevant to energy storage than that in genes associated with energy expenditure. As a result, arrays of genes were subjected to expression changes, which led to an altered homeostasis for energy storage and expenditure in favor of obesity development. Loss of Mbd2 resulted in impaired implementation of above DNA methylation changes associated with altered energy homeostasis, which then protected mice from HFD-induced obesity and insulin resistance. Those data would provide novel insight into the understanding of the pathoetiology underlying obesity with potential for developing effective therapies against obesity in clinical settings. © 2016 by the American Diabetes Association.

  2. Loss Modeling with a Data-Driven Approach in Event-Based Rainfall-Runoff Analysis

    Science.gov (United States)

    Chua, L. H. C.

    2012-04-01

    Mathematical models require the estimation of rainfall abstractions for accurate predictions of runoff. Although loss models such as the constant loss and exponential loss models are commonly used, these methods are based on simplified assumptions of the physical process. A new approach based on the data driven paradigm to estimate rainfall abstractions is proposed in this paper. The proposed data driven model, based on the artificial neural network (ANN) does not make any assumptions on the loss behavior. The estimated discharge from a physically-based model, obtained from the kinematic wave (KW) model assuming zero losses, was used as the only input to the ANN. The output is the measured discharge. Thus, the ANN functions as a black-box loss model. Two sets of data were analyzed for this study. The first dataset consists of rainfall and runoff data, measured from an artificial catchment (area = 25 m2) comprising two overland planes (slope = 11%), 25m long, transversely inclined towards a rectangular channel (slope = 2%) which conveyed the flow, recorded using calibrated weigh tanks, to the outlet. Two rain gauges, each placed 6.25 m from either ends of the channel, were used to record rainfall. Data for six storm events over the period between October 2002 and December 2002 were analyzed. The second dataset was obtained from the Upper Bukit Timah catchment (area = 6.4 km2) instrumented with two rain gauges and a flow measuring station. A total of six events recorded between November 1987 and July 1988 were selected for this study. The runoff predicted by the ANN was compared with the measured runoff. In addition, results from KW models developed for both the catchments were used as a benchmark. The KW models were calibrated assuming the loss rate for an average event for each of the datasets. The results from both the ANN and KW models agreed well with the runoff measured from the artificial catchment. The KW model is expected to perform well since the catchment

  3. Effects of farm heterogeneity and methods for upscaling on modelled nitrogen losses in agricultural landscapes

    Energy Technology Data Exchange (ETDEWEB)

    Dalgaard, T., E-mail: tommy.dalgaard@agrsci.dk [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Hutchings, N. [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Dragosits, U. [CEH Edinburgh, Bush Estate, Penicuik, Midlothian EH26 0QB, Scotland (United Kingdom); Olesen, J.E.; Kjeldsen, C. [Aarhus University, Department of Agroecology, Blichers Alle 20, P.O. Box 50, DK-8830 Tjele (Denmark); Drouet, J.L.; Cellier, P. [INRA, UMR Environnement et Grandes Cultures, BP 01, 78850 Thiverval-Grignon (France)

    2011-11-15

    The aim of this study is to illustrate the importance of farm scale heterogeneity on nitrogen (N) losses in agricultural landscapes. Results are exemplified with a chain of N models calculating farm-N balances and distributing the N-surplus to N-losses (volatilisation, denitrification, leaching) and soil-N accumulation/release in a Danish landscape. Possible non-linearities in upscaling are assessed by comparing average model results based on (i) individual farm level calculations and (ii) averaged inputs at landscape level. Effects of the non-linearities that appear when scaling up from farm to landscape are demonstrated. Especially in relation to ammonia losses the non-linearity between livestock density and N-loss is significant (p > 0.999), with around 20-30% difference compared to a scaling procedure not taking this non-linearity into account. A significant effect of farm type on soil N accumulation (p > 0.95) was also identified and needs to be included when modelling landscape level N-fluxes and greenhouse gas emissions. - Highlights: > Farm-N balances and the distribution on types of N-losses are modelled for 56 farms. > Farm type significantly affects N-losses and soil-N accumulation. > A non-linear relation between livestock density and ammonia loss is identified. > Approaches for upscaling from farm to landscape level are discussed. > Accounting farm heterogeneity is important when upscaling N-losses. - This study illustrates the importance of including non-linear effects of farm and landscape heterogeneity on the modelling and upscaling of farm nitrogen losses and greenhouse gas emissions in agricultural landscapes.

  4. Propagation Path Loss Models for 5G Urban Micro- and Macro-Cellular Scenarios

    DEFF Research Database (Denmark)

    Sun, Shu; Rappaport, Theodore S.; Rangan, Sundeep

    2016-01-01

    This paper presents and compares two candidate large-scale propagation path loss models, the alpha-beta-gamma (ABG) model and the close-in (CI) free space reference distance model, for the design of fifth generation (5G) wireless communication systems in urban micro- and macro-cellular scenarios....

  5. Eddy Current Loss Modeling for Design of PM Generators for Wind Turbines

    NARCIS (Netherlands)

    Jassal, A.

    2014-01-01

    This thesis deals with analysis, calculation and validation of eddy current loss models for Permanent Magnet (PM) direct drive generators for wind turbines. The modelling approach is a mixed use of analytical and Finite Element (FE) methods. The models are validated experimentally and design guideli

  6. Research on power grid loss prediction model based on Granger causality property of time series

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J. [North China Electric Power Univ., Beijing (China); State Grid Corp., Beijing (China); Yan, W.P.; Yuan, J. [North China Electric Power Univ., Beijing (China); Xu, H.M.; Wang, X.L. [State Grid Information and Telecommunications Corp., Beijing (China)

    2009-03-11

    This paper described a method of predicting power transmission line losses using the Granger causality property of time series. The stable property of the time series was investigated using unit root tests. The Granger causality relationship between line losses and other variables was then determined. Granger-caused time series were then used to create the following 3 prediction models: (1) a model based on line loss binomials that used electricity sales to predict variables, (2) a model that considered both power sales and grid capacity, and (3) a model based on autoregressive distributed lag (ARDL) approaches that incorporated both power sales and the square of power sales as variables. A case study of data from China's electric power grid between 1980 and 2008 was used to evaluate model performance. Results of the study showed that the model error rates ranged between 2.7 and 3.9 percent. 6 refs., 3 tabs., 1 fig.

  7. Addressing student models of energy loss in quantum tunnelling

    CERN Document Server

    Wittmann, M C; Bao, L; Wittmann, Micael C.; Morgan, Jeffrey T.; Bao, Lei

    2005-01-01

    We report on a multi-year, multi-institution study to investigate student reasoning about energy in the context of quantum tunnelling. We use ungraded surveys, graded examination questions, individual clinical interviews, and multiple-choice exams to build a picture of the types of responses that students typically give. We find that two descriptions of tunnelling through a square barrier are particularly common. Students often state that tunnelling particles lose energy while tunnelling. When sketching wave functions, students also show a shift in the axis of oscillation, as if the height of the axis of oscillation indicated the energy of the particle. We find inconsistencies between students' conceptual, mathematical, and graphical models of quantum tunnelling. As part of a curriculum in quantum physics, we have developed instructional materials to help students develop a more robust and less inconsistent picture of tunnelling, and present data suggesting that we have succeeded in doing so.

  8. Scenario Evaluator for Electrical Resistivity survey pre-modeling tool

    Science.gov (United States)

    Terry, Neil; Day-Lewis, Frederick D.; Robinson, Judith L.; Slater, Lee D; Halford, Keith J.; Binley, Andrew; Lane, John; Werkema, Dale

    2017-01-01

    Geophysical tools have much to offer users in environmental, water resource, and geotechnical fields; however, techniques such as electrical resistivity imaging (ERI) are often oversold and/or overinterpreted due to a lack of understanding of the limitations of the techniques, such as the appropriate depth intervals or resolution of the methods. The relationship between ERI data and resistivity is nonlinear; therefore, these limitations depend on site conditions and survey design and are best assessed through forward and inverse modeling exercises prior to field investigations. In this approach, proposed field surveys are first numerically simulated given the expected electrical properties of the site, and the resulting hypothetical data are then analyzed using inverse models. Performing ERI forward/inverse modeling, however, requires substantial expertise and can take many hours to implement. We present a new spreadsheet-based tool, the Scenario Evaluator for Electrical Resistivity (SEER), which features a graphical user interface that allows users to manipulate a resistivity model and instantly view how that model would likely be interpreted by an ERI survey. The SEER tool is intended for use by those who wish to determine the value of including ERI to achieve project goals, and is designed to have broad utility in industry, teaching, and research.

  9. Comoving frame models of hot star winds. II. Reduction of O star wind mass-loss rates in global models

    Science.gov (United States)

    Krtička, J.; Kubát, J.

    2017-10-01

    We calculate global (unified) wind models of main-sequence, giant, and supergiant O stars from our Galaxy. The models are calculated by solving hydrodynamic, kinetic equilibrium (also known as NLTE) and comoving frame (CMF) radiative transfer equations from the (nearly) hydrostatic photosphere to the supersonic wind. For given stellar parameters, our models predict the photosphere and wind structure and in particular the wind mass-loss rates without any free parameters. Our predicted mass-loss rates are by a factor of 2-5 lower than the commonly used predictions. A possible cause of the difference is abandoning of the Sobolev approximation for the calculation of the radiative force, because our models agree with predictions of CMF NLTE radiative transfer codes. Our predicted mass-loss rates agree nicely with the mass-loss rates derived from observed near-infrared and X-ray line profiles and are slightly lower than mass-loss rates derived from combined UV and Hα diagnostics. The empirical mass-loss rate estimates corrected for clumping may therefore be reconciled with theoretical predictions in such a way that the average ratio between individual mass-loss rate estimates is not higher than about 1.6. On the other hand, our predictions are by factor of 4.7 lower than pure Hα mass-loss rate estimates and can be reconciled with these values only assuming a microclumping factor of at least eight.

  10. Intelligent Hydraulic Actuator and Exp-based Modelling of Losses in Pumps and .

    DEFF Research Database (Denmark)

    Zhang, Muzhi

    A intelligent fuzzy logic self-organising PD+I controller for a gearrotor hydraulic motor was developed and evaluated. Furthermore, a experimental-based modelling methods with a new software tool 'Dynamodata' for modelling of losses in hydraulic motors and pumps was developed.......A intelligent fuzzy logic self-organising PD+I controller for a gearrotor hydraulic motor was developed and evaluated. Furthermore, a experimental-based modelling methods with a new software tool 'Dynamodata' for modelling of losses in hydraulic motors and pumps was developed....

  11. Mathematical Modeling for Risk Averse Firm Facing Loss Averse Customer’s Stochastic Uncertainty

    Directory of Open Access Journals (Sweden)

    Seungbeom Kim

    2017-01-01

    Full Text Available To optimize the firm’s profit during a finite planning horizon, a dynamic programming model is used to make joint pricing and inventory replenishment decision assuming that customers are loss averse and the firm is risk averse. We model the loss averse customer’s demand using the multinomial choice model. In this choice model, we consider the acquisition and transition utilities widely used by a mental accounting theory which also incorporate the reference price and actual price. Then, we show that there is an optimal inventory policy which is base-stock policy depending on the accumulated wealth in each period.

  12. Modeling weight loss and chlorogenic acids content in coffee during roasting.

    Science.gov (United States)

    Perrone, Daniel; Donangelo, Raul; Donangelo, Carmen M; Farah, Adriana

    2010-12-08

    Roasting is a key step in the production of a high-quality coffee. Roasting degree is directly related to coffee chemical composition and may be determined objectively by weight loss after roasting. Chlorogenic acids (CGA) are thermally labile phenolic compounds that play an important role in the final cup quality and health benefits of coffee. Considering the interest in finding a reliable method to predict weight loss and CGA content in coffee, models have been developed to estimate these parameters during roasting. Weight loss was successfully modeled (r = 0.99) independent of the instant temperature. CGA degradation followed first-order Arrhenius-compliant kinetic models with good predictability (r = 0.98), especially for light to moderately dark samples. In both cases distinct models for Coffea arabica and Coffea canephora were calculated, because of differences in chemical composition and cell wall structure between these species. The proposed models may become important predictive tools in the coffee industry.

  13. Modeling the response of a fast ion loss detector using orbit tracing techniques in a neutral beam prompt-loss study on the DIII-D tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Pace, D. C.; Heidbrink, W. W.; Muscatello, C. M.; Zhu, Y. B. [University of California-Irvine, Irvine, California 92697 (United States); Fisher, R. K.; Van Zeeland, M. A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Garcia-Munoz, M. [Max-Planck-Institut fuer Plasmaphysik, Garching D-85748 (Germany); Darrow, D. S.; Nazikian, R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451 (United States)

    2010-10-15

    A numerical model describing the expected measurements of neutral beam prompt-losses by a newly commissioned fast ion loss detector (FILD) in DIII-D is presented. This model incorporates the well understood neutral beam deposition profiles from all eight DIII-D beamlines to construct a prompt-loss source distribution. The full range of detectable ion orbit phase space available to the FILD is used to calculate ion trajectories that overlap with neutral beam injection footprints. Weight functions are applied to account for the level of overlap between these detectable orbits and the spatial and velocity (pitch) properties of ionized beam neutrals. An experimental comparison is performed by firing each neutral beam individually in the presence of a ramping plasma current. Fast ion losses determined from the model are in agreement with measured losses.

  14. Modeling HIV-1 drug resistance as episodic directional selection.

    Directory of Open Access Journals (Sweden)

    Ben Murrell

    Full Text Available The evolution of substitutions conferring drug resistance to HIV-1 is both episodic, occurring when patients are on antiretroviral therapy, and strongly directional, with site-specific resistant residues increasing in frequency over time. While methods exist to detect episodic diversifying selection and continuous directional selection, no evolutionary model combining these two properties has been proposed. We present two models of episodic directional selection (MEDS and EDEPS which allow the a priori specification of lineages expected to have undergone directional selection. The models infer the sites and target residues that were likely subject to directional selection, using either codon or protein sequences. Compared to its null model of episodic diversifying selection, MEDS provides a superior fit to most sites known to be involved in drug resistance, and neither one test for episodic diversifying selection nor another for constant directional selection are able to detect as many true positives as MEDS and EDEPS while maintaining acceptable levels of false positives. This suggests that episodic directional selection is a better description of the process driving the evolution of drug resistance.

  15. The effect of blood volume loss on cardiovascular response to lower body negative pressure using a mathematical model

    Science.gov (United States)

    Karam, E. H.; Srinivasan, R. S.; Charles, J. B.; Fortney, S. M.

    1994-01-01

    Different mathematical models of varying complexity have been proposed in recent years to study the cardiovascular (CV) system. However, only a few of them specifically address the response to lower body negative pressure (LBNP), a stress that can be applied in weightlessness to predict changes in orthostatic tolerance. Also, the simulated results produced by these models agree only partially with experimental observations. In contrast, the model proposed by Melchior et al., and modified by Karam et al. is a simple representation of the CV system capable of accurately reproducing observed LBNP responses up to presyncopal levels. There are significant changes in LBNP response due to a loss of blood volume and other alterations that occur in weightlessness and related one-g conditions such as bedrest. A few days of bedrest can cause up to 15% blood volume loss (BVL), with consequent decreases in both stroke volume and cardiac output, and increases in heart rate, mean arterial pressure, and total peripheral resistance. These changes are more pronounced at higher levels of LBNP. This paper presents the results of a simulation study using our CV model to examine the effect of BVL on LBNP response.

  16. The effect of blood volume loss on cardiovascular response to lower body negative pressure using a mathematical model

    Science.gov (United States)

    Karam, E. H.; Srinivasan, R. S.; Charles, J. B.; Fortney, S. M.

    1994-01-01

    Different mathematical models of varying complexity have been proposed in recent years to study the cardiovascular (CV) system. However, only a few of them specifically address the response to lower body negative pressure (LBNP), a stress that can be applied in weightlessness to predict changes in orthostatic tolerance. Also, the simulated results produced by these models agree only partially with experimental observations. In contrast, the model proposed by Melchior et al., and modified by Karam et al. is a simple representation of the CV system capable of accurately reproducing observed LBNP responses up to presyncopal levels. There are significant changes in LBNP response due to a loss of blood volume and other alterations that occur in weightlessness and related one-g conditions such as bedrest. A few days of bedrest can cause up to 15% blood volume loss (BVL), with consequent decreases in both stroke volume and cardiac output, and increases in heart rate, mean arterial pressure, and total peripheral resistance. These changes are more pronounced at higher levels of LBNP. This paper presents the results of a simulation study using our CV model to examine the effect of BVL on LBNP response.

  17. Modified pressure loss model for T-junctions of engine exhaust manifold

    Science.gov (United States)

    Wang, Wenhui; Lu, Xiaolu; Cui, Yi; Deng, Kangyao

    2014-11-01

    The T-junction model of engine exhaust manifolds significantly influences the simulation precision of the pressure wave and mass flow rate in the intake and exhaust manifolds of diesel engines. Current studies have focused on constant pressure models, constant static pressure models and pressure loss models. However, low model precision is a common disadvantage when simulating engine exhaust manifolds, particularly for turbocharged systems. To study the performance of junction flow, a cold wind tunnel experiment with high velocities at the junction of a diesel exhaust manifold is performed, and the variation in the pressure loss in the T-junction under different flow conditions is obtained. Despite the trend of the calculated total pressure loss coefficient, which is obtained by using the original pressure loss model and is the same as that obtained from the experimental results, large differences exist between the calculated and experimental values. Furthermore, the deviation becomes larger as the flow velocity increases. By improving the Vazsonyi formula considering the flow velocity and introducing the distribution function, a modified pressure loss model is established, which is suitable for a higher velocity range. Then, the new model is adopted to solve one-dimensional, unsteady flow in a D6114 turbocharged diesel engine. The calculated values are compared with the measured data, and the result shows that the simulation accuracy of the pressure wave before the turbine is improved by 4.3% with the modified pressure loss model because gas compressibility is considered when the flow velocities are high. The research results provide valuable information for further junction flow research, particularly the correction of the boundary condition in one-dimensional simulation models.

  18. Modified Pressure Loss Model for T-junctions of Engine Exhaust Manifold

    Institute of Scientific and Technical Information of China (English)

    WANG Wenhui,LU Xiaolu,CUI Yi,; DENG Kangyao

    2014-01-01

    The T-junction model of engine exhaust manifolds significantly influences the simulation precision of the pressure wave and mass flow rate in the intake and exhaust manifolds of diesel engines. Current studies have focused on constant pressure models, constant static pressure models and pressure loss models. However, low model precision is a common disadvantage when simulating engine exhaust manifolds, particularly for turbocharged systems. To study the performance of junction flow, a cold wind tunnel experiment with high velocities at the junction of a diesel exhaust manifold is performed, and the variation in the pressure loss in the T-junction under different flow conditions is obtained. Despite the trend of the calculated total pressure loss coefficient, which is obtained by using the original pressure loss model and is the same as that obtained from the experimental results, large differences exist between the calculated and experimental values. Furthermore, the deviation becomes larger as the flow velocity increases. By improving the Vazsonyi formula considering the flow velocity and introducing the distribution function, a modified pressure loss model is established, which is suitable for a higher velocity range. Then, the new model is adopted to solve one-dimensional, unsteady flow in a D6114 turbocharged diesel engine. The calculated values are compared with the measured data, and the result shows that the simulation accuracy of the pressure wave before the turbine is improved by 4.3% with the modified pressure loss model because gas compressibility is considered when the flow velocities are high. The research results provide valuable information for further junction flow research, particularly the correction of the boundary condition in one-dimensional simulation models.

  19. Combined effects of resistance training and carbohydrate-restrictive or conventional diets on weight loss, blood variables and endothelium function

    Directory of Open Access Journals (Sweden)

    Claudia Mello MEIRELLES

    Full Text Available ABSTRACT Objective: To compare the effects of either a carbohydrate-restrictive diets or a conventional hypoenergetic diet combined with resistance training. Methods: Twenty-one overweight and obese adults participated in an eight-week program consisting of progressive resistance training combined with carbohydrate-restrictive diets (initially set at <30 g carbohydrate; n=12 or conventional hypoenergetic diet (30% energetic restriction; carbohydrate/protein/lipid: 51/18/31% of total energy consumption; n=9. It was hypothesized that the carbohydrate-restrictive diets would induce greater weight loss but that both diets would elicit similar effects on selected health markers. Body mass, and body composition, blood variables and flow-mediated brachial artery dilation (flow-mediated brachial artery dilation; by ultrasound were used to assess changes due to the interventions. Results: Significant within-group reductions in body mass (-5.4±3.5%; p=0.001 versus -3.7±3.0%; p=0.015 and body fat (body fat; -10.2±7.0%; p=0.005 versus -9.6±8.8%; p=0.017 were identified for carbohydrate-restrictive diets and conventional hypoenergetic diet, respectively, but there were no significant differences between groups as the result of the interventions. Fat free mass, blood variables and flow-mediated brachial artery dilation did not significantly change, except for the total cholesterol/high-density lipoprotein ratio, which was reduced 10.4±16.9% in carbohydrate-restrictive diets (p=0.037 and 0.5±11.3% in conventional hypoenergetic diet (p=0.398. Conclusion: Carbohydrate-restrictive diets associated with resistance training was as effective as conventional hypoenergetic diet in decreasing body mass and body fat, as well as maintaining fat free mass, blood variables and flow-mediated brachial artery dilation, however it was more effective at lowering the total cholesterol/low density lipoprotein ratio.

  20. Bone loss during partial weight bearing (1/6th gravity) is mitigated by resistance and aerobic exercise in mice

    Science.gov (United States)

    Boudreaux, R. D.; Metzger, C. E.; Macias, B. R.; Shirazi-Fard, Y.; Hogan, H. A.; Bloomfield, S. A.

    2014-06-01

    Astronauts on long duration missions continue to experience bone loss, as much as 1-2% each month, for up to 4.5 years after a mission. Mechanical loading of bone with exercise has been shown to increase bone formation, mass, and geometry. The aim of this study was to compare the efficacy of two exercise protocols during a period of reduced gravitational loading (1/6th body weight) in mice. Since muscle contractions via resistance exercise impart the largest physiological loads on the skeleton, we hypothesized that resistance training (via vertical tower climbing) would better protect against the deleterious musculoskeletal effects of reduced gravitational weight bearing when compared to endurance exercise (treadmill running). Young adult female BALB/cBYJ mice were randomly assigned to three groups: 1/6 g (G/6; n=6), 1/6 g with treadmill running (G/6+RUN; n=8), or 1/6 g with vertical tower climbing (G/6+CLB; n=9). Exercise was performed five times per week. Reduced weight bearing for 21 days was achieved through a novel harness suspension system. Treadmill velocity (12-20 m/min) and daily run time duration (32-51 min) increased incrementally throughout the study. Bone geometry and volumetric bone mineral density (vBMD) at proximal metaphysis and mid-diaphysis tibia were assessed by in vivo peripheral quantitative computed tomography (pQCT) on days 0 and 21 and standard dynamic histomorphometry was performed on undemineralized sections of the mid-diaphysis after tissue harvest. G/6 caused a significant decrease (P<0.001) in proximal tibia metaphysis total vBMD (-9.6%). These reductions of tibia metaphyseal vBMD in G/6 mice were mitigated in both G/6+RUN and G/6+CLB groups (P<0.05). After 21 days of G/6, we saw an absolute increase in tibia mid-diaphysis vBMD and in distal metaphysis femur vBMD in both G/6+RUN and G/6+CLB mice (P<0.05). Substantial increases in endocortical and periosteal mineralizing surface (MS/BS) at mid-diaphysis tibia in G/6+CLB demonstrate that

  1. A Review of Flood Loss Models as Basis for Harmonization and Benchmarking.

    Directory of Open Access Journals (Sweden)

    Tina Gerl

    Full Text Available Risk-based approaches have been increasingly accepted and operationalized in flood risk management during recent decades. For instance, commercial flood risk models are used by the insurance industry to assess potential losses, establish the pricing of policies and determine reinsurance needs. Despite considerable progress in the development of loss estimation tools since the 1980s, loss estimates still reflect high uncertainties and disparities that often lead to questioning their quality. This requires an assessment of the validity and robustness of loss models as it affects prioritization and investment decision in flood risk management as well as regulatory requirements and business decisions in the insurance industry. Hence, more effort is needed to quantify uncertainties and undertake validations. Due to a lack of detailed and reliable flood loss data, first order validations are difficult to accomplish, so that model comparisons in terms of benchmarking are essential. It is checked if the models are informed by existing data and knowledge and if the assumptions made in the models are aligned with the existing knowledge. When this alignment is confirmed through validation or benchmarking exercises, the user gains confidence in the models. Before these benchmarking exercises are feasible, however, a cohesive survey of existing knowledge needs to be undertaken. With that aim, this work presents a review of flood loss-or flood vulnerability-relationships collected from the public domain and some professional sources. Our survey analyses 61 sources consisting of publications or software packages, of which 47 are reviewed in detail. This exercise results in probably the most complete review of flood loss models to date containing nearly a thousand vulnerability functions. These functions are highly heterogeneous and only about half of the loss models are found to be accompanied by explicit validation at the time of their proposal. This paper

  2. A Review of Flood Loss Models as Basis for Harmonization and Benchmarking.

    Science.gov (United States)

    Gerl, Tina; Kreibich, Heidi; Franco, Guillermo; Marechal, David; Schröter, Kai

    2016-01-01

    Risk-based approaches have been increasingly accepted and operationalized in flood risk management during recent decades. For instance, commercial flood risk models are used by the insurance industry to assess potential losses, establish the pricing of policies and determine reinsurance needs. Despite considerable progress in the development of loss estimation tools since the 1980s, loss estimates still reflect high uncertainties and disparities that often lead to questioning their quality. This requires an assessment of the validity and robustness of loss models as it affects prioritization and investment decision in flood risk management as well as regulatory requirements and business decisions in the insurance industry. Hence, more effort is needed to quantify uncertainties and undertake validations. Due to a lack of detailed and reliable flood loss data, first order validations are difficult to accomplish, so that model comparisons in terms of benchmarking are essential. It is checked if the models are informed by existing data and knowledge and if the assumptions made in the models are aligned with the existing knowledge. When this alignment is confirmed through validation or benchmarking exercises, the user gains confidence in the models. Before these benchmarking exercises are feasible, however, a cohesive survey of existing knowledge needs to be undertaken. With that aim, this work presents a review of flood loss-or flood vulnerability-relationships collected from the public domain and some professional sources. Our survey analyses 61 sources consisting of publications or software packages, of which 47 are reviewed in detail. This exercise results in probably the most complete review of flood loss models to date containing nearly a thousand vulnerability functions. These functions are highly heterogeneous and only about half of the loss models are found to be accompanied by explicit validation at the time of their proposal. This paper exemplarily presents

  3. Anti-apoptotic treatment in mouse models of age-related hearing loss

    Institute of Scientific and Technical Information of China (English)

    Fengchan Han; Oumei Wang; Quanxiang Cai

    2016-01-01

    Age-related hearing loss (AHL), or presbycusis, is the most common neurodegenerative disorder and top communication deficit of the aged population. Genetic predisposition is one of the major factors in the development of AHL. Generally, AHL is associated with an age-dependent loss of sensory hair cells, spiral ganglion neurons and stria vascularis cells in the inner ear. Although the mechanisms leading to genetic hearing loss are not completely understood, caspase-family proteases function as important signals in the inner ear pathology. It is now accepted that mouse models are the best tools to study the mechanism of genetic hearing loss or AHL. Here, we provide a brief review of recent studies on hearing improvement in mouse models of AHL by anti-apoptotic treatment.

  4. Penetration Loss Measurement and Modeling for HAP Mobile Systems in Urban Environment

    Directory of Open Access Journals (Sweden)

    Holis Jaroslav

    2008-01-01

    Full Text Available Abstract The aim of this paper is to present the results of a measurement campaign focused on the evaluation of penetration loss into buildings in an urban area as a function of the elevation angle. An empirical model to predict penetration loss into buildings is developed based on measured data obtained using a remote-controlled airship. The impact on penetration loss of different buildings and user positions within the buildings is presented. The measured data are evaluated as a function of the elevation angle. The measurement campaign was carried out at 2.0 GHz and 3.5 GHz carrier frequencies, representing the frequency band for high altitude platform third-generation mobile systems and, potentially, next generation mobile systems, mobile WiMAX, for example, the new penetration loss model can be used for system performance simulations and coverage planning.

  5. Penetration Loss Measurement and Modeling for HAP Mobile Systems in Urban Environment

    Directory of Open Access Journals (Sweden)

    Pavel Pechac

    2008-05-01

    Full Text Available The aim of this paper is to present the results of a measurement campaign focused on the evaluation of penetration loss into buildings in an urban area as a function of the elevation angle. An empirical model to predict penetration loss into buildings is developed based on measured data obtained using a remote-controlled airship. The impact on penetration loss of different buildings and user positions within the buildings is presented. The measured data are evaluated as a function of the elevation angle. The measurement campaign was carried out at 2.0 GHz and 3.5 GHz carrier frequencies, representing the frequency band for high altitude platform third-generation mobile systems and, potentially, next generation mobile systems, mobile WiMAX, for example, the new penetration loss model can be used for system performance simulations and coverage planning.

  6. EXPERIMENTAL STUDY AND MODELING OF PRESSURE LOSS FOR FOAM-CUTTINGS MIXTURE FLOW IN HORIZONTAL PIPE

    Institute of Scientific and Technical Information of China (English)

    AMNA Gumati; HIROSHI Takahshi

    2011-01-01

    In this study,we first sought to elucidate foam rheology to describe foam flow behavior,and then to experimentally investigate the pressure losses for both foam and foam-cuttings flow in a horizontal pipe by considering both varied foam qualities of 80%,85% and 90% and foam velocities.Also,a two-layer numerical model to predict pressure loss was developed based on experimental observations of cuttings behavior.Results show that the foam behaves like a power-law fluid.Furthermore,and the pressure loss significantly increases as foam velocity increases,while the delivered cuttings concentration dramatically decreases.Moreover,results indicate that both the pressure loss and the delivered cuttings concentration increase with foam quality.Comparisons between the experimental results and numerical model predictions show satisfactory agreement.

  7. The Challenges in Earthquake Loss Modelling at Urban and Regional Levels

    Science.gov (United States)

    Crowley, H.

    2009-04-01

    Constructing an earthquake loss model for a city, region or country involves compiling databases of earthquake activity, ground conditions, ground-motion prediction equations, building stock and infrastructure exposure, and vulnerability characteristics of the exposed inventory. This lecture will look at the challenges that a loss modeller is faced with when compiling these databases and combining them within a seismic risk assessment. In particular, the choices related to the geographical resolution of the exposure data, the generation of ground-motion fields in seismic hazard assessment, and the epistemic uncertainty in vulnerability assessment will be covered. Exposure data available to developers of earthquake loss models is often very crudely aggregated spatially, and in such cases very considerable effort can be required to refine the geographical resolution of the building stock inventory. The influence of the geographical resolution on loss estimates has been investigated to ascertain whether this additional effort is necessary. The results show that although the variability in the estimated losses is reduced when the distribution of the building stock inventory is known to a high resolution, the effect is largely masked by the inherent variability in the ground motion. Adequate treatment of the spatial and temporal variability in the ground motion is necessary when the aggregate loss due to all possible future earthquake events within a given region needs to be estimated. In this case, the joint probability of shaking at the different sites needs to be estimated in the seismic hazard component of the model. Conventional site-specific probabilistic seismic hazard assessment cannot be directly implemented for this purpose. Instead, an event-based procedure should be applied where a stochastic earthquake catalogue is first generated and then ground-motion fields are simulated for each event in the catalogue. This method requires the modeller to consider

  8. Interstrand contact resistance and AC loss of a 48-strands Nb3Sn CIC conductor with a Cr/Cr-oxide coating

    NARCIS (Netherlands)

    Nijhuis, Arend; Kate, ten Herman H.J.; Pantsyrny, Victor; Shikov, Alexander K.

    2000-01-01

    The interstrand contact resistance (Rc) between crossing strands in Cable-In-Conduit Conductors (CICC's) determines the coupling loss and the stability against local disturbances. The surface oxidation, surface roughness and micro-scale sliding of the contact surfaces are key parameters in the Rc. T

  9. Comparing amikacin and kanamycin-induced hearing loss in multidrug-resistant tuberculosis treatment under programmatic conditions in a Namibian retrospective cohort

    NARCIS (Netherlands)

    Sagwa, Evans L; Ruswa, Nunurai; Mavhunga, Farai; Rennie, Timothy; Leufkens, Hubert G M|info:eu-repo/dai/nl/075255049; Mantel-Teeuwisse, Aukje K|info:eu-repo/dai/nl/266775098

    2015-01-01

    BACKGROUND: Amikacin and kanamycin are mainly used for treating multidrug-resistant tuberculosis (MDR-TB), especially in developing countries where the burden of MDR-TB is highest. Their protracted use in MDR-TB treatment is known to cause dose-dependent irreversible hearing loss, requiring hearing

  10. Interstrand contact resistance and AC loss of a 48-strands Nb3Sn CIC conductor with a Cr/Cr-oxide coating

    NARCIS (Netherlands)

    Nijhuis, Arend; ten Kate, Herman H.J.; Pantsyrny, Victor; Shikov, Alexander K.

    2000-01-01

    The interstrand contact resistance (Rc) between crossing strands in Cable-In-Conduit Conductors (CICC's) determines the coupling loss and the stability against local disturbances. The surface oxidation, surface roughness and micro-scale sliding of the contact surfaces are key parameters in the Rc.

  11. Comparing amikacin and kanamycin-induced hearing loss in multidrug-resistant tuberculosis treatment under programmatic conditions in a Namibian retrospective cohort

    NARCIS (Netherlands)

    Sagwa, Evans L; Ruswa, Nunurai; Mavhunga, Farai; Rennie, Timothy; Leufkens, Hubert G M; Mantel-Teeuwisse, Aukje K

    2015-01-01

    BACKGROUND: Amikacin and kanamycin are mainly used for treating multidrug-resistant tuberculosis (MDR-TB), especially in developing countries where the burden of MDR-TB is highest. Their protracted use in MDR-TB treatment is known to cause dose-dependent irreversible hearing loss, requiring hearing

  12. Obesogenic memory can confer long-term increases in adipose tissue but not liver inflammation and insulin resistance after weight loss

    Directory of Open Access Journals (Sweden)

    J. Schmitz

    2016-05-01

    Conclusions: These results demonstrate that although sustained weight loss improves systemic glucose homeostasis, primarily through improved inflammation and insulin action in liver, a remarkable obesogenic memory can confer long-term increases in adipose tissue inflammation and insulin resistance in mice as well as in a significant subpopulation of obese patients.

  13. Testing and Modeling of Mechanical Characteristics of Resistance Welding Machines

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels;

    2003-01-01

    The dynamic mechanical response of resistance welding machine is very important to the weld quality in resistance welding especially in projection welding when collapse or deformation of work piece occurs. It is mainly governed by the mechanical parameters of machine. In this paper, a mathematical...... for both upper and lower electrode systems. This has laid a foundation for modeling the welding process and selecting the welding parameters considering the machine factors. The method is straightforward and easy to be applied in industry since the whole procedure is based on tests with no requirements...

  14. An antireflection transparent conductor with ultralow optical loss (<2 %) and electrical resistance (<6 Ω sq(-1)).

    Science.gov (United States)

    Maniyara, Rinu Abraham; Mkhitaryan, Vahagn K; Chen, Tong Lai; Ghosh, Dhriti Sundar; Pruneri, Valerio

    2016-12-19

    Transparent conductors are essential in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and solar cells. Here we demonstrate a transparent conductor with optical loss of ∼1.6%, that is, even lower than that of single-layer graphene (2.3%), and transmission higher than 98% over the visible wavelength range. This was possible by an optimized antireflection design consisting in applying Al-doped ZnO and TiO2 layers with precise thicknesses to a highly conductive Ag ultrathin film. The proposed multilayer structure also possesses a low electrical resistance (5.75 Ω sq(-1)), a figure of merit four times larger than that of indium tin oxide, the most widely used transparent conductor today, and, contrary to it, is mechanically flexible and room temperature deposited. To assess the application potentials, transparent shielding of radiofrequency and microwave interference signals with ∼30 dB attenuation up to 18 GHz was achieved.

  15. An antireflection transparent conductor with ultralow optical loss (<2 %) and electrical resistance (<6 Ω sq−1)

    Science.gov (United States)

    Maniyara, Rinu Abraham; Mkhitaryan, Vahagn K.; Chen, Tong Lai; Ghosh, Dhriti Sundar; Pruneri, Valerio

    2016-01-01

    Transparent conductors are essential in many optoelectronic devices, such as displays, smart windows, light-emitting diodes and solar cells. Here we demonstrate a transparent conductor with optical loss of ∼1.6%, that is, even lower than that of single-layer graphene (2.3%), and transmission higher than 98% over the visible wavelength range. This was possible by an optimized antireflection design consisting in applying Al-doped ZnO and TiO2 layers with precise thicknesses to a highly conductive Ag ultrathin film. The proposed multilayer structure also possesses a low electrical resistance (5.75 Ω sq−1), a figure of merit four times larger than that of indium tin oxide, the most widely used transparent conductor today, and, contrary to it, is mechanically flexible and room temperature deposited. To assess the application potentials, transparent shielding of radiofrequency and microwave interference signals with ∼30 dB attenuation up to 18 GHz was achieved. PMID:27991517

  16. Ultrasonographic measurement of the ligamentum flavum depth; is it a reliable method to distinguish true and false loss of resistance?

    Science.gov (United States)

    Pak, Michael Haejin; Lee, Won Hyung; Ko, Young Kwon; So, Sang Young; Kim, Hyun Joong

    2012-04-01

    Previous studies have shown that if performed without radiographic guidance, the loss of resistance (LOR) technique can result in inaccurate needle placement in up to 30% of lumbar epidural blocks. To date, no study has shown the efficacy of measuring the depth of the posterior complex (ligamentum flavum, epidural space, and posterior dura) ultrasonographically to distinguish true and false LOR. 40 cervical epidural blocks were performed using the LOR technique and confirmed by epidurograms. Transverse ultrasound images of the C6/7 area were taken before each cervical epidural block, and the distances from the skin to the posterior complex, transverse process, and supraspinous ligament were measured on each ultrasound view. The number of LOR attempts was counted, and the depth of each LOR was measured with a standard ruler. Correlation of false and true positive LOR depth with ultrasonographically measured depth was also statistically analyzed. 76.5% of all cases (26 out of 34) showed false positive LOR. Concordance correlation coefficients between the measured distances on ultrasound (skin to ligamentum flavum) and actual needle depth were 0.8285 on true LOR. Depth of the true positive LOR correlated with height and weight, with a mean of 5.64 ± 1.06 cm, while the mean depth of the false positive LOR was 4.08 ± 1.00 cm. Ultrasonographic measurement of the ligamentum flavum depth (or posterior complex) preceding cervical epidural block is beneficial in excluding false LOR and increasing success rates of cervical epidural blocks.

  17. Modelling of radiation losses for ion acceleration at ultra-high laser intensities

    Directory of Open Access Journals (Sweden)

    Capdessus Remi

    2013-11-01

    Full Text Available Radiation losses of charged particles can become important in ultra high intensity laser plasma interaction. This process is described by the radiation back reaction term in the electron equation of motion. This term is implemented in the relativistic particle-in-cell code by using a renormalized Lorentz-Abraham-Dirac model. In the hole boring regime case of laser ion acceleration it is shown that radiation losses results in a decrease of the piston velocity.

  18. The correlation between postmenopausal osteoporosis and inflammatory periodontitis regarding bone loss in experimental models.

    Science.gov (United States)

    Kobayashi, Megumi; Matsumoto, Chiho; Hirata, Michiko; Tominari, Tsukasa; Inada, Masaki; Miyaura, Chisato

    2012-01-01

    We have invented a mouse model of periodontitis associated with alveolar bone loss induced by lipopolysaccharide. Ovariectomized (OVX) animals are widely used as a model for osteoporosis due to estrogen deficiency. To define the relationship between periodontitis and osteoporosis, we examined the influence of estrogen deficiency on the mouse alveolar bone mass. In OVX mice, bone loss was detected not only in the femur, but also in the alveolar bone, indicating that estrogen deficiency could induce resorption in alveolar bone. In experiments using a combination of osteoporosis and periodontitis models, OVX significantly enhanced the alveolar bone loss in the model of periodontitis. Therefore, postmenopausal osteoporosis may enhance the risk of periodontitis associated with inflammatory alveolar bone resorption.

  19. An Empirical Path-Loss Model for Wireless Channels in Indoor Short-Range Office Environment

    Directory of Open Access Journals (Sweden)

    Ye Wang

    2012-01-01

    Full Text Available A novel empirical path-loss model for wireless indoor short-range office environment at 4.3–7.3 GHz band is presented. The model is developed based on the experimental datum sampled in 30 office rooms in both line of sight (LOS and non-LOS (NLOS scenarios. The model is characterized as the path loss to distance with a Gaussian random variable X due to the shadow fading by using linear regression. The path-loss exponent n is fitted by the frequency using power function and modeled as a frequency-dependent Gaussian variable as the standard deviation σ of X. The presented works should be available for the research of wireless channel characteristics under universal indoor short-distance environments in the Internet of Things (IOT.

  20. Uncovering the Best Skill Multimap by Constraining the Error Probabilities of the Gain-Loss Model

    Science.gov (United States)

    Anselmi, Pasquale; Robusto, Egidio; Stefanutti, Luca

    2012-01-01

    The Gain-Loss model is a probabilistic skill multimap model for assessing learning processes. In practical applications, more than one skill multimap could be plausible, while none corresponds to the true one. The article investigates whether constraining the error probabilities is a way of uncovering the best skill assignment among a number of…

  1. Modeling the effectiveness of tree planting to mitigate habitat loss in blue oak woodlands

    Science.gov (United States)

    Richard B. Standiford; Douglas McCreary; William Frost

    2002-01-01

    Many local conservation policies have attempted to mitigate the loss of oak woodland habitat resulting from conversion to urban or intensive agricultural land uses through tree planting. This paper models the development of blue oak (Quercus douglasii) stand structure attributes over 50 years after planting. The model uses a single tree, distance...

  2. Comparative study of model prediction of diffuse nutrient losses in response to changes in agricultural practices

    NARCIS (Netherlands)

    Vagstad, N.; French, H.K.; Andersen, H.E.; Groenendijk, P.; Siderius, C.

    2009-01-01

    This article presents a comparative study of modelled changes in nutrient losses from two European catchments caused by modifications in agricultural practices. The purpose was not to compare the actual models used, but rather to assess the uncertainties a manager may be faced with after receiving d

  3. Intelligent Hydraulic Actuator and Exp-based Modelling of Losses in Pumps and .

    DEFF Research Database (Denmark)

    Zhang, Muzhi

    A intelligent fuzzy logic self-organising PD+I controller for a gearrotor hydraulic motor was developed and evaluated. Furthermore, a experimental-based modelling methods with a new software tool 'Dynamodata' for modelling of losses in hydraulic motors and pumps was developed....

  4. Uncovering the Best Skill Multimap by Constraining the Error Probabilities of the Gain-Loss Model

    Science.gov (United States)

    Anselmi, Pasquale; Robusto, Egidio; Stefanutti, Luca

    2012-01-01

    The Gain-Loss model is a probabilistic skill multimap model for assessing learning processes. In practical applications, more than one skill multimap could be plausible, while none corresponds to the true one. The article investigates whether constraining the error probabilities is a way of uncovering the best skill assignment among a number of…

  5. Systematic review and retrospective validation of prediction models for weight loss after bariatric surgery.

    Science.gov (United States)

    Sharples, Alistair J; Mahawar, Kamal; Cheruvu, Chandra V N

    2017-08-12

    Patients often have less than realistic expectations of the weight loss they are likely to achieve after bariatric surgery. It would be useful to have a well-validated prediction tool that could give patients a realistic estimate of their expected weight loss. To perform a systematic review of the literature to identify existing prediction models and attempt to validate these models. University hospital, United Kingdom. A systematic review was performed. All English language studies were included if they used data to create a prediction model for postoperative weight loss after bariatric surgery. These models were then tested on patients undergoing bariatric surgery between January 1, 2013 and December 31, 2014 within our unit. An initial literature search produced 446 results, of which only 4 were included in the final review. Our study population included 317 patients. Mean preoperative body mass index was 46.1 ± 7.1. For 257 (81.1%) patients, 12-month follow-up was available, and mean body mass index and percentage excess weight loss at 12 months was 33.0 ± 6.7 and 66.1% ± 23.7%, respectively. All 4 of the prediction models significantly overestimated the amount of weight loss achieved by patients. The best performing prediction model in our series produced a correlation coefficient (R(2)) of .61 and an area under the curve of .71 on receiver operating curve analysis. All prediction models overestimated weight loss after bariatric surgery in our cohort. There is a need to develop better procedures and patient-specific models for better patient counselling. Copyright © 2017 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  6. Induction and direct resistance heating theory and numerical modeling

    CERN Document Server

    Lupi, Sergio; Aliferov, Aleksandr

    2015-01-01

    This book offers broad, detailed coverage of theoretical developments in induction and direct resistance heating and presents new material on the solution of problems in the application of such heating. The physical basis of induction and conduction heating processes is explained, and electromagnetic phenomena in direct resistance and induction heating of flat workpieces and cylindrical bodies are examined in depth. The calculation of electrical and energetic characteristics of induction and conduction heating systems is then thoroughly reviewed. The final two chapters consider analytical solutions and numerical modeling of problems in the application of induction and direct resistance heating, providing industrial engineers with the knowledge needed in order to use numerical tools in the modern design of installations. Other engineers, scientists, and technologists will find the book to be an invaluable reference that will assist in the efficient utilization of electrical energy.

  7. A Link Loss Model for the On-Body Propagation Channel for Binaural Hearing Aids

    Science.gov (United States)

    Chandra, Rohit; Johansson, Anders J.

    2013-12-01

    Binaural hearing aids communicate with each other through a wireless link for synchronization. A propagation model is needed to estimate the ear-to-ear link loss for such binaural hearing aids. The link loss is a critical parameter in a link budget to decide the sensitivity of the transceiver. In this paper, we have presented a model for the deterministic component of the ear-to-ear link loss. The model takes into account the dominant paths having most of the power of the creeping wave from the transceiver in one ear to the transceiver in other ear and the effect of the protruding part of the outer ear called pinna. Simulations are done to validate the model using in-the-ear (ITE) placement of antennas at 2.45 GHz on two heterogeneous phantoms of different age-group and body size. The model agrees with the simulations. The ear-to-ear link loss between the antennas for the binaural hearing aids in the homogeneous SAM phantom is compared with a heterogeneous phantom. It is found that the absence of the pinna and the lossless shell in the SAM phantom underestimate the link loss. This is verified by the measurements on a phantom where we have included the pinnas fabricated by 3D-printing.

  8. Nonlinear Stochastic Modelling of Antimicrobial resistance in Bacterial Populations

    DEFF Research Database (Denmark)

    Philipsen, Kirsten Riber

    in humans and animals. To prevent the evolution and spread of resistance, there is a need for further understanding of its dynamics. A grey-box modelling approach based on stochastic differential equations is the main and innovative method applied to study bacterial systems in this thesis. Through...... development consist mainly of optical density measurements of bacterial concentrations. At high cell densities the optical density measurements will be effected by shadow effects from the bacteria leading to an underestimation of the concentration. To circumvent this problem a exponential calibration curve...... for bacterial growth in an environment with multiple substrates. Models based on stochastic differential equations are also used in studies of mutation and conjugation. Mutation and conjugation are important mechanisms for the development of resistance. Earlier models for conjugation have described systems...

  9. Distinguishing Antimicrobial Models with Different Resistance Mechanisms via Population Pharmacodynamic Modeling.

    Directory of Open Access Journals (Sweden)

    Matthieu Jacobs

    2016-03-01

    Full Text Available Semi-mechanistic pharmacokinetic-pharmacodynamic (PK-PD modeling is increasingly used for antimicrobial drug development and optimization of dosage regimens, but systematic simulation-estimation studies to distinguish between competing PD models are lacking. This study compared the ability of static and dynamic in vitro infection models to distinguish between models with different resistance mechanisms and support accurate and precise parameter estimation. Monte Carlo simulations (MCS were performed for models with one susceptible bacterial population without (M1 or with a resting stage (M2, a one population model with adaptive resistance (M5, models with pre-existing susceptible and resistant populations without (M3 or with (M4 inter-conversion, and a model with two pre-existing populations with adaptive resistance (M6. For each model, 200 datasets of the total bacterial population were simulated over 24h using static antibiotic concentrations (256-fold concentration range or over 48h under dynamic conditions (dosing every 12h; elimination half-life: 1h. Twelve-hundred random datasets (each containing 20 curves for static or four curves for dynamic conditions were generated by bootstrapping. Each dataset was estimated by all six models via population PD modeling to compare bias and precision. For M1 and M3, most parameter estimates were unbiased (<10% and had good imprecision (<30%. However, parameters for adaptive resistance and inter-conversion for M2, M4, M5 and M6 had poor bias and large imprecision under static and dynamic conditions. For datasets that only contained viable counts of the total population, common statistical criteria and diagnostic plots did not support sound identification of the true resistance mechanism. Therefore, it seems advisable to quantify resistant bacteria and characterize their MICs and resistance mechanisms to support extended simulations and translate from in vitro experiments to animal infection models and

  10. Energy losses in switches

    Energy Technology Data Exchange (ETDEWEB)

    Martin, T.H.; Seamen, J.F.; Jobe, D.O.

    1993-07-01

    The authors experiments show energy losses between 2 and 10 times that of the resistive time predictions. The experiments used hydrogen, helium, air, nitrogen, SF{sub 6} polyethylene, and water for the switching dielectric. Previously underestimated switch losses have caused over predicting the accelerator outputs. Accurate estimation of these losses is now necessary for new high-efficiency pulsed power devices where the switching losses constitute the major portion of the total energy loss. They found that the switch energy losses scale as (V{sub peak}I{sub peak}){sup 1.1846}. When using this scaling, the energy losses in any of the tested dielectrics are almost the same. This relationship is valid for several orders of magnitude and suggested a theoretical basis for these results. Currents up to .65 MA, with voltages to 3 MV were applied to various gaps during these experiments. The authors data and the developed theory indicates that the switch power loss continues for a much longer time than the resistive time, with peak power loss generally occurring at peak current in a ranging discharge instead of the early current time. All of the experiments were circuit code modeled after developing a new switch loss version based on the theory. The circuit code predicts switch energy loss and peak currents as a function of time. During analysis of the data they noticed slight constant offsets between the theory and data that depended on the dielectric. They modified the plasma conductivity for each tested dielectric to lessen this offset.

  11. An initial-abstraction, constant-loss model for unit hydrograph modeling for applicable watersheds in Texas

    Science.gov (United States)

    Asquith, William H.; Roussel, Meghan C.

    2007-01-01

    Estimation of representative hydrographs from design storms, which are known as design hydrographs, provides for cost-effective, riskmitigated design of drainage structures such as bridges, culverts, roadways, and other infrastructure. During 2001?07, the U.S. Geological Survey (USGS), in cooperation with the Texas Department of Transportation, investigated runoff hydrographs, design storms, unit hydrographs,and watershed-loss models to enhance design hydrograph estimation in Texas. Design hydrographs ideally should mimic the general volume, peak, and shape of observed runoff hydrographs. Design hydrographs commonly are estimated in part by unit hydrographs. A unit hydrograph is defined as the runoff hydrograph that results from a unit pulse of excess rainfall uniformly distributed over the watershed at a constant rate for a specific duration. A time-distributed, watershed-loss model is required for modeling by unit hydrographs. This report develops a specific time-distributed, watershed-loss model known as an initial-abstraction, constant-loss model. For this watershed-loss model, a watershed is conceptualized to have the capacity to store or abstract an absolute depth of rainfall at and near the beginning of a storm. Depths of total rainfall less than this initial abstraction do not produce runoff. The watershed also is conceptualized to have the capacity to remove rainfall at a constant rate (loss) after the initial abstraction is satisfied. Additional rainfall inputs after the initial abstraction is satisfied contribute to runoff if the rainfall rate (intensity) is larger than the constant loss. The initial abstraction, constant-loss model thus is a two-parameter model. The initial-abstraction, constant-loss model is investigated through detailed computational and statistical analysis of observed rainfall and runoff data for 92 USGS streamflow-gaging stations (watersheds) in Texas with contributing drainage areas from 0.26 to 166 square miles. The analysis is

  12. Large-scale 3-D modeling by integration of resistivity models and borehole data through inversion

    DEFF Research Database (Denmark)

    Foged, N.; Marker, Pernille Aabye; Christiansen, A. V.;

    2014-01-01

    resistivity and the clay fraction. Through inversion we use the lithological data and the resistivity data to determine the optimum spatially distributed translator function. Applying the translator function we get a 3-D clay fraction model, which holds information from the resistivity data set....... The parameter of interest is the clay fraction, expressed as the relative length of clay units in a depth interval. The clay fraction is obtained from lithological logs and the clay fraction from the resistivity is obtained by establishing a simple petrophysical relationship, a translator function, between...... and the borehole data set in one variable. Finally, we use k-means clustering to generate a 3-D model of the subsurface structures. We apply the procedure to the Norsminde survey in Denmark, integrating approximately 700 boreholes and more than 100 000 resistivity models from an airborne survey...

  13. Modelling and prediction of crop losses from NOAA polar-orbiting operational satellites

    Directory of Open Access Journals (Sweden)

    Felix Kogan

    2016-05-01

    Full Text Available Weather-related crop losses have always been a concern for farmers, governments, traders, and policy-makers for the purpose of balanced food supply/demands, trade, and distribution of aid to the nations in need. Among weather disasters, drought plays a major role in large-scale crop losses. This paper discusses utility of operational satellite-based vegetation health (VH indices for modelling cereal yield and for early warning of drought-related crop losses. The indices were tested in Saratov oblast (SO, one of the principal grain growing regions of Russia. Correlation and regression analysis were applied to model cereal yield from VH indices during 1982–2001. A strong correlation between mean SO's cereal yield and VH indices were found during the critical period of cereals, which starts two–three weeks before and ends two–three weeks after the heading stage. Several models were constructed where VH indices served as independent variables (predictors. The models were validated independently based on SO cereal yield during 1982–2012. Drought-related cereal yield losses can be predicted three months in advance of harvest and six–eight months in advance of official grain production statistic is released. The error of production losses prediction is 7%–10%. The error of prediction drops to 3%–5% in the years of intensive droughts.

  14. Modelling the loss of genetic diversity in vole populations in a spatially and temporally varying environment

    DEFF Research Database (Denmark)

    Topping, Christopher John; Østergaard, Siri; Pertoldi, Cino

    2003-01-01

    a genetically explicit individual-based model (IBM) coupled to a dynamic landscape model was used to obtain measures for the genetic status of simulated vole populations. The rate of loss of expected heterozygosity (He) was calculated for simulated populations using two levels of spatial and temporal...... heterogeneity. Results showed that both spatial and temporal heterogeneity exerted an influence on the rate of loss of genetic diversity, but the precise effect was a balance between the effects of population sub-structuring, the frequency of founder effects and population size. These were in turn related...... of heterozygosity was corrected for the harmonic mean of the population size, the rate of loss was almost identical in the four scenarios. Unlike classical genetic models, IBMs are flexible enough to mimic real population processes under a range of environmental and behavioural conditions. We conclude that IBMs...

  15. Path Loss Prediction Over the Lunar Surface Utilizing a Modified Longley-Rice Irregular Terrain Model

    Science.gov (United States)

    Foore, Larry; Ida, Nathan

    2007-01-01

    This study introduces the use of a modified Longley-Rice irregular terrain model and digital elevation data representative of an analogue lunar site for the prediction of RF path loss over the lunar surface. The results are validated by theoretical models and past Apollo studies. The model is used to approximate the path loss deviation from theoretical attenuation over a reflecting sphere. Analysis of the simulation results provides statistics on the fade depths for frequencies of interest, and correspondingly a method for determining the maximum range of communications for various coverage confidence intervals. Communication system engineers and mission planners are provided a link margin and path loss policy for communication frequencies of interest.

  16. Yield loss prediction models based on early estimation of weed pressure

    DEFF Research Database (Denmark)

    Asif, Ali; Streibig, Jens Carl; Andreasen, Christian

    2013-01-01

    Weed control thresholds have been used to reduce costs and avoid unacceptable yield loss. Estimation of weed infestation has often been based on counts of weed plants per unit area or measurement of their relative leaf area index. Various linear, hyperbolic, and sigmoidal regression models have...... been proposed to predict yield loss, relative to yield in weed free environment from early measurements of weed infestation. The models are integrated in some weed management advisory systems. Generally, the recommendations from the advisory systems are applied to the whole field, but weed control...... time of weeds relative to crop. The aim of the review is to analyze various approaches to estimate infestation of weeds and the literature about yield loss prediction for multispecies. We discuss limitations of regression models and possible modifications to include the influential factors related...

  17. The optimal dispersal strategy: a two-patch model with travel loss

    Directory of Open Access Journals (Sweden)

    Chang-Hong Wu

    2016-03-01

    Full Text Available The dispersal of organisms plays an important role in determining the dynamics of ecological models. Ecologically, it is of interest in understanding how dispersal strategy influences the distribution of populations. An ideal free distribution (IFD of populations has been used to predict the distribution of organisms among patches, where a key assumption is to assume that species can move freely between patches without paying any cost. If instead one assumes that there are losses when species moves from one patch to another, then ideal free distributions may not appear. In this note, we examine a two-patch resident-mutant model with travel loss and predict the optimal dispersal strategy for resident and mutant. Moreover, such strategy which produces a non-IFD is evolutionarily stable. Some same and different features of patch models with travel loss are discussed.

  18. A Generalized Loss Network Model with Overflow for Capacity Planning of a Perinatal Network

    CERN Document Server

    Asaduzzaman, Md

    2011-01-01

    We develop a generalized loss network framework for capacity planning of a perinatal network in the UK. Decomposing the network by hospitals, each unit is analyzed with a GI/G/c/0 overflow loss network model. A two-moment approximation is performed to obtain the steady state solution of the GI/G/c/0 loss systems, and expressions for rejection probability and overflow probability have been derived. Using the model framework, the number of required cots can be estimated based on the rejection probability at each level of care of the neonatal units in a network. The generalization ensures that the model can be applied to any perinatal network for renewal arrival and discharge processes.

  19. Complete Loss and Thermal Model of Power Semiconductors Including Device Rating Information

    DEFF Research Database (Denmark)

    Ma, Ke; Bahman, Amir Sajjad; Beczkowski, Szymon

    2015-01-01

    profiles of the power devices can accurately be mapped, enabling more design freedom to optimize the efficiency and thermal loading of the power converter. The proposed model can be further improved by experimental tests, and it is well agreed by both circuit and Finite Element Method (FEM) simulation......Thermal loading of power devices are closely related to the reliability performance of the whole converter system. The electrical loading and device rating are both important factors that determine the loss and thermal behaviors of power semiconductor devices. In the existing loss and thermal...... models, only the electrical loadings are focused and treated as design variables, while the device rating is normally pre-defined by experience with limited design flexibility. Consequently, a more complete loss and thermal model is proposed in this paper, which takes into account not only the electrical...

  20. Modelling moisture content and dry matter loss during storage of logging residues for energy

    Energy Technology Data Exchange (ETDEWEB)

    Filbakk, Tore; Hoeiboe, Olav Albert (Dept. of Ecology and Natural Resource Management, Norwegian Univ. of Life Sciences, Aas (Norway)); Dibdiakova, Janka (Norwegian Forest and Landscape Inst., Aas (Norway)); Nurmi, Juha (Finnish Forest Research Inst., Kannus (Finland))

    2011-04-15

    To achieve optimal utilisation of logging residues for energy, it is important to know how different handling and storage methods affect fuel properties. The aim of this study was to model how the moisture content and dry matter losses of logging residues develop during storage. Logging residues were collected from five different stands of spruce and pine during different seasons of the year and stored in the same location. The logging residues were stored in covered piles of bundled residues and loose residues. Only minor differences were found in the moisture content profiles between piles of bundles and loose residues. Logging residues located in the centre of both types of piles had considerably lower moisture content than the outer parts. The moisture content significantly affected dry matter loss, with the highest dry matter losses being found in the samples with the least favourable drying conditions. The dry matter losses varied between 1 and 3% per month. Significantly higher dry matter losses were found in the spruce bundles than in the pine bundles. Seasoned logging residues had the lowest dry matter loss, while the logging residues harvested and piled in the autumn had the highest loss

  1. The impact of uncertain precipitation data on insurance loss estimates using a Flood Catastrophe Model

    Directory of Open Access Journals (Sweden)

    C. C. Sampson

    2014-01-01

    Full Text Available Catastrophe risk models used by the insurance industry are likely subject to significant uncertainty, but due to their proprietary nature and strict licensing conditions they are not available for experimentation. In addition, even if such experiments were conducted, these would not be repeatable by other researchers because commercial confidentiality issues prevent the details of proprietary catastrophe model structures from being described in public domain documents. However, such experimentation is urgently required to improve decision making in both insurance and re-insurance markets. In this paper we therefore construct our own catastrophe risk model for flooding in Dublin, Ireland in order to assess the impact of typical precipitation data uncertainty on loss predictions. As we consider only a city region rather than a whole territory and have access to detailed data and computing resources typically unavailable to industry modellers, our model is significantly more detailed than commercial products. The model consists of four components, a stochastic rainfall module, a hydrological and hydraulic flood hazard module, a vulnerability module and a financial loss module. Using these we undertake a series of simulations to test the impact of driving the stochastic event generator with four different rainfall data sets: ground gauge data, gauge corrected rainfall radar, meteorological re-analysis data (ERA-Interim and a satellite rainfall product (CMORPH. Catastrophe models are unusual because they use the upper three components of the modelling chain to generate a large synthetic database of unobserved and severe loss-driving events for which estimated losses are calculated. We find these loss estimates to be highly sensitive to uncertainties propagated from the driving observational datasets, suggesting that the range of uncertainty within catastrophe model structures may be greater than commonly believed.

  2. A Quantitative Model to Estimate Drug Resistance in Pathogens

    Directory of Open Access Journals (Sweden)

    Frazier N. Baker

    2016-12-01

    Full Text Available Pneumocystis pneumonia (PCP is an opportunistic infection that occurs in humans and other mammals with debilitated immune systems. These infections are caused by fungi in the genus Pneumocystis, which are not susceptible to standard antifungal agents. Despite decades of research and drug development, the primary treatment and prophylaxis for PCP remains a combination of trimethoprim (TMP and sulfamethoxazole (SMX that targets two enzymes in folic acid biosynthesis, dihydrofolate reductase (DHFR and dihydropteroate synthase (DHPS, respectively. There is growing evidence of emerging resistance by Pneumocystis jirovecii (the species that infects humans to TMP-SMX associated with mutations in the targeted enzymes. In the present study, we report the development of an accurate quantitative model to predict changes in the binding affinity of inhibitors (Ki, IC50 to the mutated proteins. The model is based on evolutionary information and amino acid covariance analysis. Predicted changes in binding affinity upon mutations highly correlate with the experimentally measured data. While trained on Pneumocystis jirovecii DHFR/TMP data, the model shows similar or better performance when evaluated on the resistance data for a different inhibitor of PjDFHR, another drug/target pair (PjDHPS/SMX and another organism (Staphylococcus aureus DHFR/TMP. Therefore, we anticipate that the developed prediction model will be useful in the evaluation of possible resistance of the newly sequenced variants of the pathogen and can be extended to other drug targets and organisms.

  3. Loss reduction in axial-flow compressors through low-speed model testing

    Science.gov (United States)

    Wisler, D. C.

    1984-01-01

    A systematic procedure for reducing losses in axial-flow compressors is presented. In this procedure, a large, low-speed, aerodynamic model of a high-speed core compressor is designed and fabricated based on aerodynamic similarity principles. This model is then tested at low speed where high-loss regions associated with three-dimensional endwall boundary layers flow separation, leakage, and secondary flows can be located, detailed measurements made, and loss mechanisms determined with much greater accuracy and much lower cost and risk than is possible in small, high-speed compressors. Design modifications are made by using custom-tailored airfoils and vector diagrams, airfoil endbends, and modified wall geometries in the high-loss regions. The design improvements resulting in reduced loss or increased stall margin are then scaled to high speed. This paper describes the procedure and presents experimental results to show that in some cases endwall loss has been reduced by as much as 10 percent, flow separation has been reduced or eliminated, and stall margin has been substantially improved by using these techniques.

  4. Prospective large-scale field study generates predictive model identifying major contributors to colony losses.

    Directory of Open Access Journals (Sweden)

    Merav Gleit Kielmanowicz

    2015-04-01

    Full Text Available Over the last decade, unusually high losses of colonies have been reported by beekeepers across the USA. Multiple factors such as Varroa destructor, bee viruses, Nosema ceranae, weather, beekeeping practices, nutrition, and pesticides have been shown to contribute to colony losses. Here we describe a large-scale controlled trial, in which different bee pathogens, bee population, and weather conditions across winter were monitored at three locations across the USA. In order to minimize influence of various known contributing factors and their interaction, the hives in the study were not treated with antibiotics or miticides. Additionally, the hives were kept at one location and were not exposed to potential stress factors associated with migration. Our results show that a linear association between load of viruses (DWV or IAPV in Varroa and bees is present at high Varroa infestation levels (>3 mites per 100 bees. The collection of comprehensive data allowed us to draw a predictive model of colony losses and to show that Varroa destructor, along with bee viruses, mainly DWV replication, contributes to approximately 70% of colony losses. This correlation further supports the claim that insufficient control of the virus-vectoring Varroa mite would result in increased hive loss. The predictive model also indicates that a single factor may not be sufficient to trigger colony losses, whereas a combination of stressors appears to impact hive health.

  5. Hysteresis model and statistical interpretation of energy losses in non-oriented steels

    Energy Technology Data Exchange (ETDEWEB)

    Mănescu, Veronica, E-mail: veronica.paltanea@upb.ro; Păltânea, Gheorghe; Gavrilă, Horia

    2016-04-01

    In this paper the hysteresis energy losses in two non-oriented industrial steels (M400-65A and M800-65A) were determined, by means of an efficient classical Preisach model, which is based on the Pescetti–Biorci method for the identification of the Preisach density. The excess and the total energy losses were also determined, using a statistical framework, based on magnetic object theory. The hysteresis energy losses, in a non-oriented steel alloy, depend on the peak magnetic polarization and they can be computed using a Preisach model, due to the fact that in these materials there is a direct link between the elementary rectangular loops and the discontinuous character of the magnetization process (Barkhausen jumps). To determine the Preisach density it was necessary to measure the normal magnetization curve and the saturation hysteresis cycle. A system of equations was deduced and the Preisach density was calculated for a magnetic polarization of 1.5 T; then the hysteresis cycle was reconstructed. Using the same pattern for the Preisach distribution, it was computed the hysteresis cycle for 1 T. The classical losses were calculated using a well known formula and the excess energy losses were determined by means of the magnetic object theory. The total energy losses were mathematically reconstructed and compared with those, measured experimentally.

  6. Hippocampal adaptive response following extensive neuronal loss in an inducible transgenic mouse model.

    Directory of Open Access Journals (Sweden)

    Kristoffer Myczek

    Full Text Available Neuronal loss is a common component of a variety of neurodegenerative disorders (including Alzheimer's, Parkinson's, and Huntington's disease and brain traumas (stroke, epilepsy, and traumatic brain injury. One brain region that commonly exhibits neuronal loss in several neurodegenerative disorders is the hippocampus, an area of the brain critical for the formation and retrieval of memories. Long-lasting and sometimes unrecoverable deficits caused by neuronal loss present a unique challenge for clinicians and for researchers who attempt to model these traumas in animals. Can these deficits be recovered, and if so, is the brain capable of regeneration following neuronal loss? To address this significant question, we utilized the innovative CaM/Tet-DT(A mouse model that selectively induces neuronal ablation. We found that we are able to inflict a consistent and significant lesion to the hippocampus, resulting in hippocampally-dependent behavioral deficits and a long-lasting upregulation in neurogenesis, suggesting that this process might be a critical part of hippocampal recovery. In addition, we provide novel evidence of angiogenic and vasculature changes following hippocampal neuronal loss in CaM/Tet-DTA mice. We posit that angiogenesis may be an important factor that promotes neurogenic upregulation following hippocampal neuronal loss, and both factors, angiogenesis and neurogenesis, can contribute to the adaptive response of the brain for behavioral recovery.

  7. Hysteresis model and statistical interpretation of energy losses in non-oriented steels

    Science.gov (United States)

    Mănescu (Păltânea), Veronica; Păltânea, Gheorghe; Gavrilă, Horia

    2016-04-01

    In this paper the hysteresis energy losses in two non-oriented industrial steels (M400-65A and M800-65A) were determined, by means of an efficient classical Preisach model, which is based on the Pescetti-Biorci method for the identification of the Preisach density. The excess and the total energy losses were also determined, using a statistical framework, based on magnetic object theory. The hysteresis energy losses, in a non-oriented steel alloy, depend on the peak magnetic polarization and they can be computed using a Preisach model, due to the fact that in these materials there is a direct link between the elementary rectangular loops and the discontinuous character of the magnetization process (Barkhausen jumps). To determine the Preisach density it was necessary to measure the normal magnetization curve and the saturation hysteresis cycle. A system of equations was deduced and the Preisach density was calculated for a magnetic polarization of 1.5 T; then the hysteresis cycle was reconstructed. Using the same pattern for the Preisach distribution, it was computed the hysteresis cycle for 1 T. The classical losses were calculated using a well known formula and the excess energy losses were determined by means of the magnetic object theory. The total energy losses were mathematically reconstructed and compared with those, measured experimentally.

  8. Loss reduction in axial-flow compressors through low-speed model testing

    Science.gov (United States)

    Wisler, D. C.

    1984-01-01

    A systematic procedure for reducing losses in axial-flow compressors is presented. In this procedure, a large, low-speed, aerodynamic model of a high-speed core compressor is designed and fabricated based on aerodynamic similarity principles. This model is then tested at low speed where high-loss regions associated with three-dimensional endwall boundary layers flow separation, leakage, and secondary flows can be located, detailed measurements made, and loss mechanisms determined with much greater accuracy and much lower cost and risk than is possible in small, high-speed compressors. Design modifications are made by using custom-tailored airfoils and vector diagrams, airfoil endbends, and modified wall geometries in the high-loss regions. The design improvements resulting in reduced loss or increased stall margin are then scaled to high speed. This paper describes the procedure and presents experimental results to show that in some cases endwall loss has been reduced by as much as 10 percent, flow separation has been reduced or eliminated, and stall margin has been substantially improved by using these techniques.

  9. Prospective large-scale field study generates predictive model identifying major contributors to colony losses.

    Science.gov (United States)

    Kielmanowicz, Merav Gleit; Inberg, Alex; Lerner, Inbar Maayan; Golani, Yael; Brown, Nicholas; Turner, Catherine Louise; Hayes, Gerald J R; Ballam, Joan M

    2015-04-01

    Over the last decade, unusually high losses of colonies have been reported by beekeepers across the USA. Multiple factors such as Varroa destructor, bee viruses, Nosema ceranae, weather, beekeeping practices, nutrition, and pesticides have been shown to contribute to colony losses. Here we describe a large-scale controlled trial, in which different bee pathogens, bee population, and weather conditions across winter were monitored at three locations across the USA. In order to minimize influence of various known contributing factors and their interaction, the hives in the study were not treated with antibiotics or miticides. Additionally, the hives were kept at one location and were not exposed to potential stress factors associated with migration. Our results show that a linear association between load of viruses (DWV or IAPV) in Varroa and bees is present at high Varroa infestation levels (>3 mites per 100 bees). The collection of comprehensive data allowed us to draw a predictive model of colony losses and to show that Varroa destructor, along with bee viruses, mainly DWV replication, contributes to approximately 70% of colony losses. This correlation further supports the claim that insufficient control of the virus-vectoring Varroa mite would result in increased hive loss. The predictive model also indicates that a single factor may not be sufficient to trigger colony losses, whereas a combination of stressors appears to impact hive health.

  10. A dynamical model for describing behavioural interventions for weight loss and body composition change.

    Science.gov (United States)

    Navarro-Barrientos, J-Emeterio; Rivera, Daniel E; Collins, Linda M

    2011-01-12

    We present a dynamical model incorporating both physiological and psychological factors that predicts changes in body mass and composition during the course of a behavioral intervention for weight loss. The model consists of a three-compartment energy balance integrated with a mechanistic psychological model inspired by the Theory of Planned Behavior (TPB). The latter describes how important variables in a behavioural intervention can influence healthy eating habits and increased physical activity over time. The novelty of the approach lies in representing the behavioural intervention as a dynamical system, and the integration of the psychological and energy balance models. Two simulation scenarios are presented that illustrate how the model can improve the understanding of how changes in intervention components and participant differences affect outcomes. Consequently, the model can be used to inform behavioural scientists in the design of optimised interventions for weight loss and body composition change.

  11. Vortex methods to answer the need for improved understanding and modelling of tip-loss factors

    DEFF Research Database (Denmark)

    Branlard, Emmanuel; Dixon, Kristian; Gaunaa, Mac

    2013-01-01

    Standard blade element momentum (BEM) codes use Prandtl¿s tip-loss correction which relies on simplified vortex theory under the assumption of optimal operating condition and no wake expansion. The various tip-loss functions found in the literature are listed. A simple comparison between them shows...... important differences in Annual Energy Production which reveal a large uncertainty in current BEM-based computations. A new tip-loss correction for implementation in BEM codes has been developed using a lifting-line code to account for the effect of wake expansion, roll-up and distortion under many...... operating conditions. A database of tip-loss corrections is established for further use in BEM codes. This model is closer to the physics of the flow and hence, a better assessment of the performance of wind turbines by this method is expected. © The Institution of Engineering and Technology 2013...

  12. Practical modeling of acoustic losses in air due to heat conduction and viscosity

    DEFF Research Database (Denmark)

    Christensen, René; Juhl, Peter Møller; Cutanda Henríquez, Vicente

    2008-01-01

    Accurate acoustics models of small devices with cavities and narrow slits and ducts should include the socalled boundary layer attenuation caused by thermal conduction and viscosity. The purpose of this paper is to present and compare different methods for including these loss mechanisms in analy......Accurate acoustics models of small devices with cavities and narrow slits and ducts should include the socalled boundary layer attenuation caused by thermal conduction and viscosity. The purpose of this paper is to present and compare different methods for including these loss mechanisms...

  13. A comparison of different murine models for cytomegalovirus-induced sensorineural hearing loss.

    Science.gov (United States)

    Wang, Yong; Patel, Rusha; Ren, Chongyu; Taggart, Michael G; Firpo, Matthew A; Schleiss, Mark R; Park, Albert H

    2013-11-01

    To compare three different inoculation techniques for the development of cytomegalovirus (CMV)-induced sensorineural hearing loss (SNHL) in a mouse model. A prospective experimental animal study. BALB/c mice underwent inoculation using green fluorescent protein-expressing mouse cytomegalovirus (mCMV-GFP) via transtympanic (TT), intraperitoneal (IP), or intracranial (IC) routes. Control mice received an equal volume of saline. Hearing thresholds were measured using both distortion product otoacoustic emissions (DPOAE) and evoked auditory brainstem response studies (ABR). Cochleas were harvested for histological examination and cytocochleogram. No mice in the TT or IP groups showed significant hearing loss. All infected mice in the IC group showed significantly elevated ABR and DPOAE thresholds at 4 weeks of age. Ten mice (55%) had profound hearing loss (≥80 dB) at 4 weeks of age, while the other eight mice (45%) initially showed moderate hearing loss (≤20 dB), which progressed to profound hearing loss by 6 to 8 weeks. Asymmetric hearing loss was seen in 40% of the mice. Temporal bone histology showed diffuse loss of outer hair cells (OHC). Green fluorescent protein (GFP)-labeled virus was abundant in the spiral ganglion and adjacent to the scala tympani at the basal region of the cochlea at 7 days postinjection, and devoid of GFP labeling by 14 days postinfection. Intracerebral injection of mCMV preferentially causes mCMV-mediated hearing loss relative to IP or TT injections. These results are consistent with the hearing loss reported in human congenital infection and may have implications for understanding the pathophysiology of CMV-mediated labyrinthitis. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  14. Insulin resistance in the NIDDM model Psammomys obesus in the normoglycaemic, normoinsulinaemic state.

    Science.gov (United States)

    Ziv, E; Kalman, R; Hershkop, K; Barash, V; Shafrir, E; Bar-On, H

    1996-11-01

    The desert gerbil Psammomys obesus ("sand rat"), a model of nutritionally induced insulin resistance and non-insulin-dependent diabetes mellitus, was treated after weaning with exogenous insulin implants in the normoglycaemic, normoinsulinaemic state. Albino rats matched for weight and age served as high energy diet adjusted reference animals. Insulin administration, elevating the serum insulin to 6000 pmol/l resulted in only a mild reduction in blood glucose levels in Psammomys, but caused a severe, often fatal hypoglycaemia in the albino rats. The hepatic response to insulin-induced hypoglycaemia in rats involved a significant loss in glycogen and suppression of phosphoenolpyruvate carboxykinase (PEPCK) activity. In Psammomys under similar hyperinsulinaemia no appreciable changes in liver glycogen and PEPCK activity were evident, indicating that blood glucose was replenished by continuing gluconeogenesis. Euglycaemic, hyperinsulinaemic clamp caused a complete shut-down of hepatic glucose production in albino rats. However, in both diabetes-prone and diabetes-resistant Psammomys lines, mean hepatic glucose production was reduced by only 62 to 53% respectively, despite longer lasting and higher levels of hyperinsulinaemia. These results indicate that Psammomys is characterized by muscle and liver insulin resistance prior to diet-induced hyperglycaemia and hyperinsulinaemia. This is assumed to be a species feature of Psammomys, exemplifying a metabolic adjustment to survival in conditions of food scarcity of both animal and human populations. It may reflect a propensity to insulin resistance and hyperglycaemia in population groups exposed to affluent nutrition.

  15. Thermal boundary resistance from transient nanocalorimetry: A multiscale modeling approach

    Science.gov (United States)

    Caddeo, Claudia; Melis, Claudio; Ronchi, Andrea; Giannetti, Claudio; Ferrini, Gabriele; Rurali, Riccardo; Colombo, Luciano; Banfi, Francesco

    2017-02-01

    The thermal boundary resistance at the interface between a nanosized Al film and an Al2O3 substrate is investigated at an atomistic level. The thermal dynamics occurring in time-resolved thermoreflectance experiments is then modeled via macrophysics equations upon insertion of the materials parameters obtained from atomistic simulations. Electrons and phonons nonequilibrium and spatiotemporal temperatures inhomogeneities are found to persist up to the nanosecond time scale. These results question the validity of the commonly adopted lumped thermal capacitance model in interpreting transient nanocalorimetry experiments. The strategy adopted in the literature to extract the thermal boundary resistance from transient reflectivity traces is revised in the light of the present findings. The results are of relevance beyond the specific system, the physical picture being general and readily extendable to other heterojunctions.

  16. Mathematical model of temephos resistance in Aedes aegypti mosquito population

    Science.gov (United States)

    Aldila, D.; Nuraini, N.; Soewono, E.; Supriatna, A. K.

    2014-03-01

    Aedes aegypti is the main vector of dengue disease in many tropical and sub-tropical countries. Dengue became major public concern in these countries due to the unavailability of vaccine or drugs for dengue disease in the market. Hence, the only way to control the spread of DF and DHF is by controlling the vectors carrying the disease, for instance with fumigation, temephos or genetic manipulation. Many previous studies conclude that Aedes aegypti may develop resistance to many kind of insecticide, including temephos. Mathematical model for transmission of temephos resistance in Aedes aegypti population is discussed in this paper. Nontrivial equilibrium point of the system and the corresponding existence are shown analytically. The model analysis have shown epidemiological trends condition that permits the coexistence of nontrivial equilibrium is given analytically. Numerical results are given to show parameter sensitivity and some cases of worsening effect values for illustrating possible conditions in the field.

  17. Modeling mass drug treatment and resistant filaria disease transmission

    Science.gov (United States)

    Fuady, A. M.; Nuraini, N.; Soewono, E.; Tasman, H.; Supriatna, A. K.

    2014-03-01

    It has been indicated that a long term application of combined mass drug treatment may contribute to the development of drug resistance in lymphatic filariasis. This phenomenon is not well understood due to the complexity of filaria life cycle. In this paper we formulate a mathematical model for the spread of mass drug resistant in a filaria endemic region. The model is represented in a 13-dimensional Host-Vector system. The basic reproductive ratio of the system which is obtained from the next generation matrix, and analysis of stability of both the disease free equilibrium and the coexistence equilibria are shown. Numerical simulation for long term dynamics for possible field conditions is also shown.

  18. Fatigue Modeling via Mammalian Auditory System for Prediction of Noise Induced Hearing Loss.

    Science.gov (United States)

    Sun, Pengfei; Qin, Jun; Campbell, Kathleen

    2015-01-01

    Noise induced hearing loss (NIHL) remains as a severe health problem worldwide. Existing noise metrics and modeling for evaluation of NIHL are limited on prediction of gradually developing NIHL (GDHL) caused by high-level occupational noise. In this study, we proposed two auditory fatigue based models, including equal velocity level (EVL) and complex velocity level (CVL), which combine the high-cycle fatigue theory with the mammalian auditory model, to predict GDHL. The mammalian auditory model is introduced by combining the transfer function of the external-middle ear and the triple-path nonlinear (TRNL) filter to obtain velocities of basilar membrane (BM) in cochlea. The high-cycle fatigue theory is based on the assumption that GDHL can be considered as a process of long-cycle mechanical fatigue failure of organ of Corti. Furthermore, a series of chinchilla experimental data are used to validate the effectiveness of the proposed fatigue models. The regression analysis results show that both proposed fatigue models have high corrections with four hearing loss indices. It indicates that the proposed models can accurately predict hearing loss in chinchilla. Results suggest that the CVL model is more accurate compared to the EVL model on prediction of the auditory risk of exposure to hazardous occupational noise.

  19. Fatigue Modeling via Mammalian Auditory System for Prediction of Noise Induced Hearing Loss

    Directory of Open Access Journals (Sweden)

    Pengfei Sun

    2015-01-01

    Full Text Available Noise induced hearing loss (NIHL remains as a severe health problem worldwide. Existing noise metrics and modeling for evaluation of NIHL are limited on prediction of gradually developing NIHL (GDHL caused by high-level occupational noise. In this study, we proposed two auditory fatigue based models, including equal velocity level (EVL and complex velocity level (CVL, which combine the high-cycle fatigue theory with the mammalian auditory model, to predict GDHL. The mammalian auditory model is introduced by combining the transfer function of the external-middle ear and the triple-path nonlinear (TRNL filter to obtain velocities of basilar membrane (BM in cochlea. The high-cycle fatigue theory is based on the assumption that GDHL can be considered as a process of long-cycle mechanical fatigue failure of organ of Corti. Furthermore, a series of chinchilla experimental data are used to validate the effectiveness of the proposed fatigue models. The regression analysis results show that both proposed fatigue models have high corrections with four hearing loss indices. It indicates that the proposed models can accurately predict hearing loss in chinchilla. Results suggest that the CVL model is more accurate compared to the EVL model on prediction of the auditory risk of exposure to hazardous occupational noise.

  20. Mars atmospheric losses induced by the solar wind: Comparison of observations with models

    Science.gov (United States)

    Vaisberg, Oleg

    2015-12-01

    With new results from Mars-Express on plasma environment of Mars and two new Mars satellites the study Martian atmospheric losses receives new attention. Paper summarizes experimental results concentrating on configuration of Martian magnetosphere and the measurements of planetary ion escape induced by the solar wind. Several plasma populations constituting solar wind induced mass loss have been identified and studied: pick-up ions in shocked solar wind flow and induced (accretion) tail, ions accelerated in the tail current sheet, and outflow of ionospheric ions. Measured ion flux values and calculations of the total escape rate including solar cycle variations are summarized. Several types of simulation of the solar wind with Mars are considered and results of representative models are given and compared with experimental results. These computer models allowed one to much better understand solar wind-Mars interaction. However, there is significant difference between total loss rates obtained from simulation and ones from measurements on the spacecraft. Both measurements and simulation provide significant flux values that are considered as an important factor of mass loss during cosmogonic time of the planet. The origin of each solar wind induced loss component and its contribution to total amount are discussed and compared with relevant computer models. Future progress in experiments and simulation is briefly discussed.

  1. Mathematical Model Defining Volumetric Losses of Hydraulic Oil Compression in a Variable Capacity Displacement Pump

    Directory of Open Access Journals (Sweden)

    Paszota Zygmunt

    2015-01-01

    Full Text Available The objective of the work is to develop the capability of evaluating the volumetric losses of hydraulic oil compression in the working chambers of high pressure variable capacity displacement pump. Volumetric losses of oil compression must be determined as functions of the same parameters, which the volumetric losses due to leakage, resulting from the quality of design solution of the pump, are evaluated as dependent on and also as function of the oil aeration coefficient Ɛ. A mathematical model has been developed describing the hydraulic oil compressibility coefficient klc|Δppi;Ɛ;v as a relation to the ratio ΔpPi/pn of indicated increase ΔpPi of pressure in the working chambers and the nominal pressure pn, to the pump capacity coefficient bP, to the oil aeration coefficient  and to the ratio v/vnof oil viscosity v and reference viscosity vn. A mathematical model is presented of volumetric losses qpvc|ΔpPi;bp;;vof hydraulic oil compression in the pump working chambers in the form allowing to use it in the model of power of losses and energy efficiency

  2. Detailed models for timing and efficiency in resistive plate chambers

    CERN Document Server

    Riegler, Werner

    2003-01-01

    We discuss detailed models for detector physics processes in Resistive Plate Chambers, in particular including the effect of attachment on the avalanche statistics. In addition, we present analytic formulas for average charges and intrinsic RPC time resolution. Using a Monte Carlo simulation including all the steps from primary ionization to the front-end electronics we discuss the dependence of efficiency and time resolution on parameters like primary ionization, avalanche statistics and threshold.

  3. Modeling of Discontinuities in Resistance Structures due to Corrosion

    Directory of Open Access Journals (Sweden)

    Daniel Boboş

    2011-05-01

    Full Text Available The corrosion process is a process that produces significant negative effects on the resistance structures by reducing their section and by deterioration of mechanical properties of materials. In this paper are presented some notions about the corrosion process, types of corrosion encountered and types of geometric models that can be used for analytical calculation and for numerical simulation using finite element analysis programs, of the effects produced in the corrosion process on the natural frequency of the structure elements.

  4. The combined effects of soya isoflavones and resistant starch on equol production and trabecular bone loss in ovariectomised mice.

    Science.gov (United States)

    Tousen, Yuko; Matsumoto, Yu; Matsumoto, Chiho; Nishide, Yoriko; Nagahata, Yuya; Kobayashi, Isao; Ishimi, Yoshiko

    2016-07-01

    Equol is a metabolite of the soya isoflavone (ISO) daidzein that is produced by intestinal microbiota. Equol has greater oestrogenic activity compared with other ISO, and it prevents bone loss in postmenopausal women. Resistant starch (RS), which has a prebiotic activity and is a dietary fibre, was reported to promote equol production. Conversely, the intestinal microbiota is reported to directly regulate bone health by reducing inflammatory cytokine levels and T-lymphocytes in bone. The present study evaluated the combined effects of diet supplemented with ISO and RS on intestinal microbiota, equol production, bone mineral density (BMD) and inflammatory gene expression in the bone marrow of ovariectomised (OVX) mice. Female ddY strain mice, aged 8 weeks, were either sham-operated (Sham, n 7) or OVX. OVX mice were randomly divided into the following four groups (seven per group): OVX control (OVX); OVX fed 0·05 % ISO diet (OVX+ISO); OVX fed 9 % RS diet (OVX+RS); and OVX fed 0·05 % ISO- and 9 % RS diet (OVX+ISO+RS). After 6 weeks, treatment with the combination of ISO and RS increased equol production, prevented the OVX-induced decline in trabecular BMD in the distal femur by modulating the enteric environment and altered OVX-induced inflammation-related gene expression in the bone marrow. However, there were no significant differences in bone parameters between the ISO+RS and ISO-alone groups in OVX mice. Our findings suggest that the combination of ISO and RS might alter intestinal microbiota and immune status in the bone marrow, resulting in attenuated bone resorption in OVX mice.

  5. Episodic Mass Loss on the Timescale of Thermal Pulses: Radiative Transfer Modeling.

    Science.gov (United States)

    Speck, Angela; Nenkova, Maia; Meixner, Margaret; Eltizur, Moshe; Knapp, Gillian

    Using far-infrared observations obtained from the Infrared Space Observatory (ISO), we have discovered extremely large dust shells around two post-AGB stars (the Egg Nebula and AFGL 618; Speck, Meixner & Knapp 2001). These circumstellar shells contain the fossil record of their previous AGB mass loss. The radial profiles of these dust shells suggest that episodic mass loss has occurred with mass-loss enhancements on timescales corresponding to theoretical predictions of thermal pulses on the AGB. By modeling the dust emission, we can constrain how the mass loss varies as stars evolve on the AGB, which will constrain the mass-loss mechanisms. Furthermore this modeling allows the determination of the density distribution of the dust around the protoplanetary nebulae as a function of radius. However, modeling such large dust shells is not trivial. Previous studies of very large circumstellar shells showed that most of the outer shell is heated by the interstellar radiation field (ISRF) rather than the central star. Therefore using radiative transfer models with only the central star heating the dust is unrealistic. Furthermore, where the circumstellar shell ploughs into the surrounding interstellar medium may lead to a pile up of material at the outer edge of the dust shell. We present results of modeling the very large dust shells around the Egg Nebula and AFGL 618 using a version of the 1-d radiative transfer code DUSTY which includes external heating of the dust by the ISRF. The models require that the innermost regions has a rapid (1r3) dust density drop-off, indicative of the increased mass-loss rate towards the end of the AGB. Further out, the dust shell has an underlying 1r2 density drop-off, with two superimposed density enhancements. These results provide constraints on the spatial extent of increased density regions and therefore on the duration of increased mass-loss episodes. Furthermore, the modeling suggests that the mass loss rate was either higher in

  6. A Tree-based Approach for Modelling Interception Loss From Evergreen Oak Mediterranean Savannas

    Science.gov (United States)

    Pereira, Fernando L.; Gash, John H. C.; David, Jorge S.; David, Teresa S.; Monteiro, Paulo R.; Valente, Fernanda

    2010-05-01

    Evaporation of rainfall intercepted by tree canopies is usually an important part of the overall water balance of forested catchments and there have been many studies dedicated to measuring and modelling rainfall interception loss. These studies have mainly been conducted in dense forests; there have been few studies on the very sparse forests which are common in dry and semi-arid areas. Water resources are scarce in these areas making sparse forests particularly important. Methods for modelling interception loss are thus required to support sustainable water management in those areas. In very sparse forests, trees occur as widely spaced individuals rather than as a continuous forest canopy. We therefore suggest that interception loss for this vegetation type can be more adequately modelled if the overall forest evaporation is derived by scaling up the evaporation from individual trees. The evaporation rate for a single tree can be estimated using a simple Dalton-type diffusion equation for water vapour as long as its surface temperature is known. From theory, this temperature is shown to be dependent upon the available energy and windspeed. However, the surface temperature of a fully saturated tree crown, under rainy conditions, should approach the wet bulb temperature as the radiative energy input to the tree reduces to zero. This was experimentally confirmed from measurements of the radiation balance and surface temperature of an isolated tree crown. Thus, evaporation of intercepted rainfall can be estimated using an equation which only requires knowledge of the air dry and wet bulb temperatures and of the bulk tree-crown aerodynamic conductance. This was taken as the basis of a new approach for modelling interception loss from savanna-type woodland, i.e. by combining the Dalton-type equation with the Gash's analytical model to estimate interception loss from isolated trees. This modelling approach was tested using data from two Mediterranean savanna-type oak

  7. Model distinguishability and inference robustness in mechanisms of cholera transmission and loss of immunity.

    Science.gov (United States)

    Lee, Elizabeth C; Kelly, Michael R; Ochocki, Brad M; Akinwumi, Segun M; Hamre, Karen E S; Tien, Joseph H; Eisenberg, Marisa C

    2017-01-24

    Mathematical models of cholera and waterborne disease vary widely in their structures, in terms of transmission pathways, loss of immunity, and a range of other features. These differences can affect model dynamics, with different models potentially yielding different predictions and parameter estimates from the same data. Given the increasing use of mathematical models to inform public health decision-making, it is important to assess model distinguishability (whether models can be distinguished based on fit to data) and inference robustness (whether inferences from the model are robust to realistic variations in model structure). In this paper, we examined the effects of uncertainty in model structure in the context of epidemic cholera, testing a range of models with differences in transmission and loss of immunity structure, based on known features of cholera epidemiology. We fit these models to simulated epidemic and long-term data, as well as data from the 2006 Angola epidemic. We evaluated model distinguishability based on fit to data, and whether the parameter values, model behavior, and forecasting ability can accurately be inferred from incidence data. In general, all models were able to successfully fit to all data sets, both real and simulated, regardless of whether the model generating the simulated data matched the fitted model. However, in the long-term data, the best model fits were achieved when the loss of immunity structures matched those of the model that simulated the data. Two parameters, one representing person-to-person transmission and the other representing the reporting rate, were accurately estimated across all models, while the remaining parameters showed broad variation across the different models and data sets. The basic reproduction number (R0) was often poorly estimated even using the correct model, due to practical unidentifiability issues in the waterborne transmission pathway which were consistent across all models. Forecasting

  8. Emergence of colistin resistance without loss of fitness and virulence after prolonged colistin administration in a patient with extensively drug-resistant Acinetobacter baumannii.

    Science.gov (United States)

    Durante-Mangoni, Emanuele; Del Franco, Mariateresa; Andini, Roberto; Bernardo, Mariano; Giannouli, Maria; Zarrilli, Raffaele

    2015-07-01

    The spread of extensively drug-resistant (XDR) gram-negative bacteria has boosted colistin use, with a resultant selection of colistin-resistant, often pandrug-resistant strains. Whether acquisition of further resistance mechanisms translates into a reduced virulence is the subject of active research. In this report, we describe clinical features of an immunocompromised patient who developed infection due to colistin-resistant Acinetobacter baumannii while on long-term colistin therapy. We analyzed phenotypic and genotypic characteristics, molecular mechanisms of colistin resistance, and in vitro and in vivo fitness of sequential colistin-sensitive and colistin-resistant strains isolated from the patient. Both colistin-sensitive and colistin-resistant strains were XDR and showed identical ST78 genotype. At variance with prior reports on colistin-resistant strains of A. baumannii, resistance to colistin due to P233S mutation in PmrB sensor kinase did not associate with any measurable reduction in strain fitness, growth characteristics, and virulence.

  9. Performance Analysis and Modeling of Thermally Sprayed Resistive Heaters

    Science.gov (United States)

    Lamarre, Jean-Michel; Marcoux, Pierre; Perrault, Michel; Abbott, Richard C.; Legoux, Jean-Gabriel

    2013-08-01

    Many processes and systems require hot surfaces. These are usually heated using electrical elements located in their vicinity. However, this solution is subject to intrinsic limitations associated with heating element geometry and physical location. Thermally spraying electrical elements directly on surfaces can overcome these limitations by tailoring the geometry of the heating element to the application. Moreover, the element heat transfer is maximized by minimizing the distance between the heater and the surface to be heated. This article is aimed at modeling and characterizing resistive heaters sprayed on metallic substrates. Heaters were fabricated by using a plasma-sprayed alumina dielectric insulator and a wire flame-sprayed iron-based alloy resistive element. Samples were energized and kept at a constant temperature of 425 °C for up to 4 months. SEM cross-sectional observations revealed the formation of cracks at very specific locations in the alumina layer after thermal use. Finite-element modeling shows that these cracks originate from high local thermal stresses and can be predicted according to the considered geometry. The simulation model was refined using experimental parameters obtained by several techniques such as emissivity and time-dependent temperature profile (infra-red camera), resistivity (four-probe technique), thermal diffusivity (laser flash method), and mechanical properties (micro and nanoindentation). The influence of the alumina thickness and the substrate material on crack formation was evaluated.

  10. A Link Loss Model for the On-body Propagation Channel for Binaural Hearing Aids

    CERN Document Server

    Chandra, Rohit

    2013-01-01

    Binaural hearing aids communicate with each other through a wireless link for synchronization. A propagation model is needed to estimate the ear-to-ear link loss for such binaural hearing aids. The link loss is a critical parameter in a link budget to decide the sensitivity of the transceiver. In this paper, we have presented a model for the deterministic component of the ear-to-ear link loss. The model takes into account the dominant paths having most of the power of the creeping wave from the transceiver in one ear to the transceiver in other ear and the effect of the protruding part of the outer ear called pinna. Simulations are done to validate the model using in-the-ear (ITE) placement of antennas at 2.45 GHz on two heterogeneous phantoms of different age-group and body size. The model agrees with the simulations. The ear-to-ear link loss between the antennas for the binaural hearing aids in the homogeneous SAM phantom is compared with a heterogeneous phantom. It is found that the absence of the pinna an...

  11. Use of Equivalent Loss Models Under Section 316(b of the Clean Water Act

    Directory of Open Access Journals (Sweden)

    William Dey

    2002-01-01

    Full Text Available Equivalent loss models encompass a variety of life table-based approaches that can be used to convert age- and life stage-specific estimates of entrainment and impingement loss to a common, easily understood currency. This common currency can be expressed in terms of numbers of individuals, yield to the fishery, or biomass to the ecosystem. These models have at least two key uses in the Section 316(b assessment process: screening for adverse environmental impact (AEI and determination of environmental benefits associated with intake alternatives. This paper reviews the various forms of equivalent loss models, their data input requirements, and their assumptions and limitations. In addition, it describes how these models can be used as a second-level screening tool as part of the assessment of the potential for AEI. Given their relative simplicity and ease of use, equivalent loss models should prove to be an important tool in the arsenal of impact assessment methods for Section 316(b.

  12. Isotonic Modeling with Non-Differentiable Loss Functions with Application to Lasso Regularization.

    Science.gov (United States)

    Painsky, Amichai; Rosset, Saharon

    2016-02-01

    In this paper we present an algorithmic approach for fitting isotonic models under convex, yet non-differentiable, loss functions. It is a generalization of the greedy non-regret approach proposed by Luss and Rosset (2014) for differentiable loss functions, taking into account the sub-gradiental extensions required. We prove that our suggested algorithm solves the isotonic modeling problem while maintaining favorable computational and statistical properties. As our suggested algorithm may be used for any non-differentiable loss function, we focus our interest on isotonic modeling for either regression or two-class classification with appropriate log-likelihood loss and lasso penalty on the fitted values. This combination allows us to maintain the non-parametric nature of isotonic modeling, while controlling model complexity through regularization. We demonstrate the efficiency and usefulness of this approach on both synthetic and real world data. An implementation of our suggested solution is publicly available from the first author's website (https://sites.google.com/site/amichaipainsky/software).

  13. Model for the Path Loss of In-room Reverberant Channels

    DEFF Research Database (Denmark)

    Steinböck, Gerhard; Pedersen, Troels; Fleury, Bernard Henri

    2011-01-01

    A general path loss model for in-room radio channels is proposed. The model is based on experimental observations of the behavior of the delay power spectrum in closed rooms. In a given closed room, the early part of the spectrum observed at different positions typically consists of a dominant...... allows for the prediction of path loss, mean delay, and RMS delay spread versus distance. We use measurements to validate the proposed model and we observe good agreement of the model prediction for mean delay and RMS delay spread....... component (peak) that vanishes as the transmitter-receiver distance increases, while the late part decays versus distance according to the same exponential law regardless of this distance. These observations motivate the proposed model of the delay power spectrum with an early dominant component...

  14. Determination of suitable drying curve model for bread moisture loss during baking

    Science.gov (United States)

    Soleimani Pour-Damanab, A. R.; Jafary, A.; Rafiee, S.

    2013-03-01

    This study presents mathematical modelling of bread moisture loss or drying during baking in a conventional bread baking process. In order to estimate and select the appropriate moisture loss curve equation, 11 different models, semi-theoretical and empirical, were applied to the experimental data and compared according to their correlation coefficients, chi-squared test and root mean square error which were predicted by nonlinear regression analysis. Consequently, of all the drying models, a Page model was selected as the best one, according to the correlation coefficients, chi-squared test, and root mean square error values and its simplicity. Mean absolute estimation error of the proposed model by linear regression analysis for natural and forced convection modes was 2.43, 4.74%, respectively.

  15. Comparative Analysis of Empirical Path Loss Model for Cellular Transmission in Rivers State

    Directory of Open Access Journals (Sweden)

    B.O.H Akinwole, Biebuma J.J

    2013-08-01

    Full Text Available This paper presents a comparative analysis of three empirical path loss models with measured data for urban, suburban, and rural areas in Rivers State. The three models investigated were COST 231 Hata, SUI,ECC-33models. A downlink data was collected at operating frequency of 2100MHz using drive test procedure consisting of test mobile phones to determine the received signal power (RSCP at specified receiver distanceson a Globacom Node Bs located in some locations in the State. This test was carried out for investigating the effectiveness of the commonly used existing models for Cellular transmission. The results analysed were based on Mean Square Error (MSE and Standard Deviation (SD and were simulated on MATLAB (7.5.0. The results show that COST 231 Hata model gives better predictions and therefore recommended for path loss predictions in River State.

  16. Validation of a probabilistic model for hurricane insurance loss projections in Florida

    Energy Technology Data Exchange (ETDEWEB)

    Pinelli, J.-P. [Florida Tech, Melbourne, Florida (United States)], E-mail: pinelli@fit.edu; Gurley, K.R. [University of Florida, Gainesville, Florida (United States); Subramanian, C.S. [Florida Tech, Melbourne, Florida (United States); Hamid, S.S. [Florida International University, Miami, Florida (United States); Pita, G.L. [Florida Tech, Melbourne, Florida (United States)

    2008-12-15

    The Florida Public Hurricane Loss Model is one of the first public models accessible for scrutiny to the scientific community, incorporating state of the art techniques in hurricane and vulnerability modeling. The model was developed for Florida, and is applicable to other hurricane-prone regions where construction practice is similar. The 2004 hurricane season produced substantial losses in Florida, and provided the means to validate and calibrate this model against actual claim data. This paper presents the predicted losses for several insurance portfolios corresponding to hurricanes Andrew, Charley, and Frances. The predictions are validated against the actual claim data. Physical damage predictions for external building components are also compared to observed damage. The analyses show that the predictive capabilities of the model were substantially improved after the calibration against the 2004 data. The methodology also shows that the predictive capabilities of the model could be enhanced if insurance companies report more detailed information about the structures they insure and the types of damage they suffer. This model can be a powerful tool for the study of risk reduction strategies.

  17. The relevance of mouse models for investigating age-related bone loss in humans.

    Science.gov (United States)

    Jilka, Robert L

    2013-10-01

    Mice are increasingly used for investigation of the pathophysiology of osteoporosis because their genome is easily manipulated, and their skeleton is similar to that of humans. Unlike the human skeleton, however, the murine skeleton continues to grow slowly after puberty and lacks osteonal remodeling of cortical bone. Yet, like humans, mice exhibit loss of cancellous bone, thinning of cortical bone, and increased cortical porosity with advancing age. Histologic evidence in mice and humans alike indicates that inadequate osteoblast-mediated refilling of resorption cavities created during bone remodeling is responsible. Mouse models of progeria also show bone loss and skeletal defects associated with senescence of early osteoblast progenitors. Additionally, mouse models of atherosclerosis, which often occurs in osteoporotic participants, also suffer bone loss, suggesting that common diseases of aging share pathophysiological pathways. Knowledge of the causes of skeletal fragility in mice should therefore be applicable to humans if inherent limitations are recognized.

  18. Optimization of biomass torrefaction conditions by the gain and loss method and regression model analysis.

    Science.gov (United States)

    Lee, Soo Min; Lee, Jae-Won

    2014-11-01

    In this study, the optimal conditions for biomass torrefaction were determined by comparing the gain of energy content to the weight loss of biomass from the final products. Torrefaction experiments were performed at temperatures ranging from 220 to 280°C using 20-80min reaction times. Polynomial regression models ranging from the 1st to the 3rd order were used to determine a relationship between the severity factor (SF) and calorific value or weight loss. The intersection of two regression models for calorific value and weight loss was determined and assumed to be the optimized SF. The optimized SFs on each biomass ranged from 6.056 to 6.372. Optimized torrefaction conditions were determined at various reaction times of 15, 30, and 60min. The average optimized temperature was 248.55°C in the studied biomass when torrefaction was performed for 60min.

  19. Assessment of weld thickness loss in offshore pipelines using computed radiography and computational modeling

    Energy Technology Data Exchange (ETDEWEB)

    Correa, S.C.A. [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Centro Universitario Estadual da Zona Oeste - UEZO, Avenida Manuel Caldeira de Alvarenga, 1203, 23070-200, Rio de Janeiro, RJ (Brazil)], E-mail: scorrea@con.ufrj.br; Souza, E.M. [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Departamento de Geologia/IGEO, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Oliveira, D.F. [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Silva, A.X. [PEN/COPPE-DNC/Poli-CT, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Lopes, R.T. [Programa de Engenharia Nuclear, COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Marinho, C.; Camerini, C.S. [CENPES/PDEP/TMEC/PETROBRAS, Ilha do Fundao, Cidade Universitaria, 21949-900, Rio de Janeiro, RJ (Brazil)

    2009-10-15

    In order to guarantee the structural integrity of oil plants it is crucial to monitor the amount of weld thickness loss in offshore pipelines. However, in spite of its relevance, this parameter is very difficult to determine, due to both the large diameter of most pipes and the complexity of the multi-variable system involved. In this study, a computational modeling based on Monte Carlo MCNPX code is combined with computed radiography to estimate the weld thickness loss in large-diameter offshore pipelines. Results show that computational modeling is a powerful tool to estimate intensity variations in radiographic images generated by weld thickness variations, and it can be combined with computed radiography to assess weld thickness loss in offshore and subsea pipelines.

  20. Estimation of financial loss ratio for E-insurance:a quantitative model

    Institute of Scientific and Technical Information of China (English)

    钟元生; 陈德人; 施敏华

    2002-01-01

    In view of the risk of E-commerce and the response of the insurance industry to it, this paper is aimed at one important point of insurance, that is, estimation of financial loss ratio, which is one of the most difficult problems facing the E-insurance industry. This paper proposes a quantitative analyzing model for estimating E-insurance financial loss ratio. The model is based on gross income per enterprise and CSI/FBI computer crime and security survey. The analysis results presented are reasonable and valuable for both insurer and the insured and thus can be accepted by both of them. What we must point out is that according to our assumption, the financial loss ratio varied very little, 0.233% in 1999 and 0.236% in 2000 although there was much variation in the main data of the CSI/FBI survey.

  1. A Discrete SIRS Model with Kicked Loss of Immunity and Infection Probability

    Science.gov (United States)

    Paladini, F.; Renna, I.; Renna, L.

    2011-03-01

    A discrete-time deterministic epidemic model is proposed with the aim of reproducing the behaviour observed in the incidence of real infectious diseases, such as oscillations and irregularities. For this purpose we introduce, in a naïve discrete-time SIRS model, seasonal variability in the loss of immunity and in the infection probability, modelled by sequences of kicks. Restrictive assumptions are made on the parameters of the models, in order to guarantee that the transitions are determined by true probabilities, so that comparisons with stochastic discrete-time previsions can be also provided. Numerical simulations show that the characteristics of real infectious diseases can be adequately modeled.

  2. A Discrete SIRS Model with Kicked Loss of Immunity and Infection Probability

    Energy Technology Data Exchange (ETDEWEB)

    Paladini, F; Renna, L [Dipartimento di Fisica dell' Universita del Salento, 73100 Lecce (Italy); Renna, I, E-mail: luigi.renna@le.infn.it [ISIR, Universite Pierre et Marie Curie/CNRS, F-75005 Paris (France)

    2011-03-01

    A discrete-time deterministic epidemic model is proposed with the aim of reproducing the behaviour observed in the incidence of real infectious diseases, such as oscillations and irregularities. For this purpose we introduce, in a naive discrete-time SIRS model, seasonal variability in the loss of immunity and in the infection probability, modelled by sequences of kicks. Restrictive assumptions are made on the parameters of the models, in order to guarantee that the transitions are determined by true probabilities, so that comparisons with stochastic discrete-time previsions can be also provided. Numerical simulations show that the characteristics of real infectious diseases can be adequately modeled.

  3. Identifying Intracellular pDNA Losses From a Model of Nonviral Gene Delivery.

    Science.gov (United States)

    Martin, Timothy Michael; Wysocki, Beata Joanna; Wysocki, Tadeusz Antoni; Pannier, Angela K

    2015-06-01

    Nonviral gene delivery systems are a type of nanocommunication system that transmit plasmid packets (i.e., pDNA packets) that are programmed at the nanoscale to biological systems at the microscopic cellular level. This engineered nanocommunication system suffers large pDNA losses during transmission of the genetically encoded information, preventing its use in biotechnological and medical applications. The pDNA losses largely remain uncharacterized, and the ramifications of reducing pDNA loss from newly designed gene delivery systems remain difficult to predict. Here, the pDNA losses during primary and secondary transmission chains were identified utilizing a MATLAB model employing queuing theory simulating delivery of pEGFPLuc transgene to HeLa cells carried by Lipofectamine 2000 nonviral DNA carrier. Minimizing pDNA loss during endosomal escape of the primary transmission process results in increased number of pDNA in the nucleus with increased transfection, but with increased probability of cell death. The number of pDNA copies in the nucleus and the amount of time the pDNAs are in the nucleus directly correlates to improved transfection efficiency. During secondary transmission, pDNAs are degraded during distribution to daughter cells. Reducing pDNA losses improves transfection, but a balance in quantity of nuclear pDNA, mitosis, and toxicity must be considered in order to achieve therapeutically relevant transfection levels.

  4. Characterization of efficiency-limiting resistance losses in monolithically integrated Cu(In,Ga)Se2 solar modules.

    Science.gov (United States)

    Yoon, Ju-Heon; Park, Jong-Keuk; Kim, Won Mok; Lee, JinWoo; Pak, Hisun; Jeong, Jeung-Hyun

    2015-01-09

    The cell-to-module efficiency gap in Cu(In,Ga)Se2 (CIGS) monolithically integrated solar modules is enhanced by contact resistance between the Al-doped ZnO (AZO) and Mo back contact layers, the P2 contact, which connects adjacent cells. The present work evaluated the P2 contact resistance, in addition to the TCO resistance, using an embedded transmission line structure in a commercial-grade module without using special sample fabrication methods. The AZO layers between cells were not scribed; instead, the CIGS/CdS/i-ZnO/AZO device was patterned in a long stripe to permit measurement of the Mo electrode pair resistance over current paths through two P2 contacts (Mo/AZO) and along the AZO layer. The intercept and slope of the resistance as a function of the electrode interval yielded the P2 contact resistance and the TCO resistance, respectively. Calibration of the parasitic resistances is discussed as a method of improving the measurement accuracy. The contribution of the P2 contact resistance to the series resistance was comparable to that of the TCO resistance, and its origin was attributed to remnant MoSe2 phases in the P2 region, as verified by transmission electron microscopy.

  5. Achieving Fast Reconnection in Resistive MHD Models via Turbulent Means

    CERN Document Server

    Lapenta, Giovanni

    2011-01-01

    Astrophysical fluids are generally turbulent and this preexisting turbulence must be taken into account for the models of magnetic reconnection which are attepmted to be applied to astrophysical, solar or heliospheric environments. In addition, reconnection itself induces turbulence which provides an important feedback on the reconnection process. In this paper we discuss both theoretical model and numerical evidence that magnetic reconnection gets fast in the approximation of resistive MHD. We consider the relation between the Lazarian & Vishniac turbulent reconnection theory and Lapenta's numerical experiments testifying of the spontaneous onset of turbulent reconnection in systems which are initially laminar.

  6. Contact Modelling in Resistance Welding, Part II: Experimental Validation

    DEFF Research Database (Denmark)

    Song, Quanfeng; Zhang, Wenqi; Bay, Niels

    2006-01-01

    Contact algorithms in resistance welding presented in the previous paper are experimentally validated in the present paper. In order to verify the mechanical contact algorithm, two types of experiments, i.e. sandwich upsetting of circular, cylindrical specimens and compression tests of discs...... with a solid ring projection towards a flat ring, are carried out at room temperature. The complete algorithm, involving not only the mechanical model but also the thermal and electrical models, is validated by projection welding experiments. The experimental results are in satisfactory agreement...

  7. Basic models modeling resistance training: an update for basic scientists interested in study skeletal muscle hypertrophy.

    Science.gov (United States)

    Cholewa, Jason; Guimarães-Ferreira, Lucas; da Silva Teixeira, Tamiris; Naimo, Marshall Alan; Zhi, Xia; de Sá, Rafaele Bis Dal Ponte; Lodetti, Alice; Cardozo, Mayara Quadros; Zanchi, Nelo Eidy

    2014-09-01

    Human muscle hypertrophy brought about by voluntary exercise in laboratorial conditions is the most common way to study resistance exercise training, especially because of its reliability, stimulus control and easy application to resistance training exercise sessions at fitness centers. However, because of the complexity of blood factors and organs involved, invasive data is difficult to obtain in human exercise training studies due to the integration of several organs, including adipose tissue, liver, brain and skeletal muscle. In contrast, studying skeletal muscle remodeling in animal models are easier to perform as the organs can be easily obtained after euthanasia; however, not all models of resistance training in animals displays a robust capacity to hypertrophy the desired muscle. Moreover, some models of resistance training rely on voluntary effort, which complicates the results observed when animal models are employed since voluntary capacity is something theoretically impossible to measure in rodents. With this information in mind, we will review the modalities used to simulate resistance training in animals in order to present to investigators the benefits and risks of different animal models capable to provoke skeletal muscle hypertrophy. Our second objective is to help investigators analyze and select the experimental resistance training model that best promotes the research question and desired endpoints.

  8. POPULATION CONSEQUENCES OF WINTER HABITAT LOSS IN A MIGRATORY SHOREBIRD .1. ESTIMATING MODEL PARAMETERS

    NARCIS (Netherlands)

    GOSSCUSTARD, JD; CLARKE, RT; BRIGGS, KB; ENS, BJ; EXO, KM; SMIT, C; BEINTEMA, AJ; CALDOW, RWG; CATT, DC; CLARK, NA; DURELL, SEALD; HARRIS, MP; HULSCHER, JB; MEININGER, PL; PICOZZI, N; PRYSJONES, R; SAFRIEL, UN; WEST, AD

    1995-01-01

    1. In order to construct a model to predict the effect of winter habitat loss on the migratory population of the European subspecies of the oystercatcher, Haematopus ostralegus ostralegus, data on the reproductive and mortality rates collected throughout Europe over the last 60 years are reviewed. W

  9. On the distribution of discounted loss reserves using generalized linear models

    NARCIS (Netherlands)

    Hoedemakers, T.; Beirlant, J.; Goovaerts, M.J.; Dhaene, J.

    2005-01-01

    Renshaw and Verrall [11] specified the generalized linear model (GLM) underlying the chain-ladder technique and suggested some other GLMs which might be useful in claims reserving. The purpose of this paper is to construct bounds for the discounted loss reserve within the framework of GLMs. Exact

  10. Modeling losses of copper-based fungicide foliar sprays in wash-off under simulated rain

    DEFF Research Database (Denmark)

    Pérez-Rodríguez, P.; Paradelo Pérez, Marcos; Soto-Gómez, D.

    2015-01-01

    Wash-off experiments of three Cu-based fungicides were conducted with a single raindrop simulator with known drop size and fall height. Losses were quantified as total Cu (CuT), in solution (CuL), and particulate (CuP). Cu wash-off time course was modeled for two different drop sizes using a stoc...

  11. From Cyclone Tracks to the Costs of European Winter Storms: A Probabilistic Loss Assessment Model

    Science.gov (United States)

    Orwig, K.; Renggli, D.; Corti, T.; Reese, S.; Wueest, M.; Viktor, E.; Zimmerli, P.

    2014-12-01

    European winter storms cause billions of dollars of insured losses every year. Therefore, it is essential to understand potential impacts of future events, and the role reinsurance can play to mitigate the losses. The authors will present an overview on natural catastrophe risk assessment modeling in the reinsurance industry, and the development of a new innovative approach for modeling the risk associated with European winter storms.The new innovative approach includes the development of physically meaningful probabilistic (i.e. simulated) events for European winter storm loss assessment. The meteorological hazard component of the new model is based on cyclone and windstorm tracks identified in the 20thCentury Reanalysis data. The knowledge of the evolution of winter storms both in time and space allows the physically meaningful perturbation of historical event properties (e.g. track, intensity, etc.). The perturbation includes a random element but also takes the local climatology and the evolution of the historical event into account.The low-resolution wind footprints taken from the 20thCentury Reanalysis are processed by a statistical-dynamical downscaling to generate high-resolution footprints for both the simulated and historical events. Downscaling transfer functions are generated using ENSEMBLES regional climate model data. The result is a set of reliable probabilistic events representing thousands of years. The event set is then combined with country and site-specific vulnerability functions and detailed market- or client-specific information to compute annual expected losses.

  12. Reducing power losses caused by ionic shortcut currents in reverse electrodialysis stacks by a validated model

    NARCIS (Netherlands)

    Veerman, J.; Post, J. W.; Saakes, M.; Metz, S. J.; Harmsen, G. J.

    2008-01-01

    Both in electrodialysis and in reverse electrodialysis ionic shortcut currents through feed and drain channels cause a considerable loss in efficiency. Model calculations based on an equivalent electric system of a reverse electrodialysis stack reveal that the effect of these salt bridges could be r

  13. Loss of Parvalbumin in the Hippocampus of MAM Schizophrenia Model Rats Is Attenuated by Peripubertal Diazepam

    OpenAIRE

    Du, Yijuan; Grace, Anthony A.

    2016-01-01

    Background: Loss of parvalbumin interneurons in the hippocampus is a robust finding in schizophrenia brains. Rats exposed during embryonic day 17 to methylazoxymethanol acetate exhibit characteristics consistent with an animal model of schizophrenia, including decreased parvalbumin interneurons in the ventral hippocampus. We reported previously that peripubertal administration of diazepam prevented the emergence of pathophysiology in adult methylazoxymethanol acetate rats. Methods: We used an...

  14. Modularised process-based modelling of phosphorus loss at farm and catchment scale

    Directory of Open Access Journals (Sweden)

    M. G. Hutchins

    2002-01-01

    Full Text Available In recent years, a co-ordinated programme of data collection has resulted in the collation of sub-hourly time-series of hydrological, sediment and phosphorus loss data, together with soil analysis, cropping and management information for two small ( Keywords: phosphorus, erosion, process-based modelling, agriculture

  15. Acquisition and loss of desiccation tolerance in seeds : from experimental model to biological relevance

    NARCIS (Netherlands)

    Dekkers, Bas J W|info:eu-repo/dai/nl/326091572; Costa, Maria Cecilia D; Maia, Julio; Bentsink, Leónie|info:eu-repo/dai/nl/241338735; Ligterink, Wilco; Hilhorst, Henk W M

    2015-01-01

    MAIN CONCLUSION: Besides being an important model to study desiccation tolerance, the induction of desiccation tolerance in germinated seeds may also play an ecological role in seedling establishment. Desiccation tolerance (DT) is the ability of certain organisms to survive extreme water losses with

  16. Path loss modelling and comparison based on the radio propagation measurement at 3.5GHz

    Institute of Scientific and Technical Information of China (English)

    Wang Ping; Li Yingzhe; Chang Ruoting; Sun Kun; Xu Hui

    2009-01-01

    Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propagation characteristics are proposed for the field test of Chinese 4th generation (4G) trial system. The measurement system is established for 3.5GHz based on the sophisticated measurement instruments and the virtual instrument technology. The characteristic parameters of radio propagation such as path loss (PL) exponent and shadow fading standard deviation are extracted from measurement data, which result in the path loss model finally. The comparisons with other existing international models results validate our measurement in terms of path loss model. Based on the analysis of the existing extension model assumed for the microwave frequency at 3.5GHz, we find that the Stanford University Interim (SUI) model fits very well with the measurement result in the hotspot scenario, while the COST 231 model is closer to the measurement result in the suburban scenario. This result provides a measurement-based channel reference for the development of the future IMT-Advanced systems in China.

  17. Refining definitions of periodontal disease and caries for prediction models of incident tooth loss.

    Science.gov (United States)

    Houshmand, Mohammad; Holtfreter, Birte; Berg, Marie Henrike; Schwahn, Christian; Meisel, Peter; Biffar, Reiner; Kindler, Stefan; Kocher, Thomas

    2012-07-01

    To assess the suitability of different definitions of caries and periodontitis for inclusion in tooth loss prediction models. The Study of Health in Pomerania (SHIP) is a population-based cohort study conducted in 1997-2001 (SHIP-0) and 2002-2006 (SHIP-1). This sample comprised 2,780 subjects aged 20-81 years with complete information on dental and periodontal status [DMFS status, clinical attachment loss (CAL) and probing depth (PD)]. Analyses on five-year tooth loss were limited to half-mouth data. The predictive value of tested definitions was markedly age- and gender-dependent: in 20-39-aged men, the number of decayed or filled surfaces best predicted the number of lost teeth, whereas in young women CAL≥4 mm performed best. In older subjects, periodontal definitions were superior to caries definitions: mean CAL performed best in 40-59-year olds, whereas AL- or PD-related definitions predicted best in 60-81-year olds. On tooth level, mean CAL was the superior definition to assess 5-year incident tooth loss in all strata except for young men. Caries parameters best predicted incident tooth loss in men aged 20-39 years; in the intermediate and oldest age group and in young women, mean AL was most informative. Therefore, prediction models need to be developed for different age and gender groups. © 2012 John Wiley & Sons A/S.

  18. Fusobacterium nucleatum and Tannerella forsythia induce synergistic alveolar bone loss in a mouse periodontitis model.

    Science.gov (United States)

    Settem, Rajendra P; El-Hassan, Ahmed Taher; Honma, Kiyonobu; Stafford, Graham P; Sharma, Ashu

    2012-07-01

    Tannerella forsythia is strongly associated with chronic periodontitis, an inflammatory disease of the tooth-supporting tissues, leading to tooth loss. Fusobacterium nucleatum, an opportunistic pathogen, is thought to promote dental plaque formation by serving as a bridge bacterium between early- and late-colonizing species of the oral cavity. Previous studies have shown that F. nucleatum species synergize with T. forsythia during biofilm formation and pathogenesis. In the present study, we showed that coinfection of F. nucleatum and T. forsythia is more potent than infection with either species alone in inducing NF-κB activity and proinflammatory cytokine secretion in monocytic cells and primary murine macrophages. Moreover, in a murine model of periodontitis, mixed infection with the two species induces synergistic alveolar bone loss, characterized by bone loss which is greater than the additive alveolar bone losses induced by each species alone. Further, in comparison to the single-species infection, mixed infection caused significantly increased inflammatory cell infiltration in the gingivae and osteoclastic activity in the jaw bones. These data show that F. nucleatum subspecies and T. forsythia synergistically stimulate the host immune response and induce alveolar bone loss in a murine experimental periodontitis model.

  19. Validation of Tilt Gain under Realistic Path Loss Model and Network Scenario

    DEFF Research Database (Denmark)

    Nguyen, Huan Cong; Rodriguez, Ignacio; Sørensen, Troels Bundgaard

    2013-01-01

    Despite being a simple and commonly-applied radio optimization technique, the impact on practical network performance from base station antenna downtilt is not well understood. Most published studies based on empirical path loss models report tilt angles and performance gains that are far higher...... than practical experience suggests. We motivate in this paper, based on a practical LTE scenario, that the discrepancy partly lies in the path loss model, and shows that a more detailed semi-deterministic model leads to both lower gains in terms of SINR, outage probability and downlink throughput...... settings, including the use of electrical and/or mechanical antenna downtilt, and therefore it is possible to find multiple optimum tilt profiles in a practical case. A broader implication of this study is that care must be taken when using the 3GPP model to evaluate advanced adaptive antenna techniques...

  20. Percolation Model of Sensory Transmission and Loss of Consciousness under General Anesthesia

    Science.gov (United States)

    Zhou, David W.; Mowrey, David D.; Tang, Pei; Xu, Yan

    2015-01-01

    Neurons communicate with each other dynamically. How such communications lead to consciousness remains unclear. Here, we present a theoretical model to understand the dynamic nature of sensory activity and information integration in a hierarchical network, in which edges are stochastically defined by a single parameter, p, representing percolation probability of information transmission. We validate the model by comparing the transmitted and original signal distributions and show that a basic version of this model can reproduce key spectral features clinically observed in electroencephalographic recordings of transitions from conscious to unconscious brain activities during general anesthesia. As p decreases, a steep divergence of the transmitted signal from the original was observed, along with a loss of signal synchrony and a sharp increase in information entropy in a critical manner, resembling the precipitous loss of consciousness during anesthesia. The model offers mechanistic insights into the emergence of information integration from a stochastic process, laying the foundation to understand the origin of cognition. PMID:26382705

  1. Initial Condition Model from Imaginary Part of Action and the Information Loss

    CERN Document Server

    Nielsen, H B

    2009-01-01

    We review slightly a work by Horowitz and Maldecena solving the information loss problem for black holes by having inside the blackhole - near to the singularity - a boundary condition, as e.g the no boundary proposal by Hartle and Hawking. Here we propose to make this boundary condition come out of our imaginary action model (together with Masao Ninomiya). This model naturally begins effectively to set up boundaries - whether it be in future or past! - especially strongly whenever we reach to high energy physics regimes, such as near the black hole singularity, or in Higgs producing machines as LHC or SSC. In such cases one can say our model predicts miracles. The point is that you may say that the information loss problem, unless you solve it in other ways, call for such a violation of time causality as in our imaginary action model!

  2. Modeling and simulation of orlistat to predict weight loss and weight maintenance in obesity patients.

    Science.gov (United States)

    Nakai, Kiyohiko; Wada, Russell; Iida, Satofumi; Kawanishi, Takehiko; Matsumoto, Yoshiaki

    2014-01-01

    Orlistat is used clinically worldwide as anti-obesity drug. It is a chemically synthesized hydrogenated derivative of lipstatin and is an inhibitor of gastric and pancreatic lipases. It has been found to reduce the absorption of dietary fat in the gastrointestinal tract. Modeling and simulation based on pharmacokinetic/pharmacodynamic analysis is becoming increasingly used in the design of clinical trials to assure that the trials are of high quality and are conducted efficiently. We developed a clinical trial simulation model for orlistat based on Phase III clinical study data. This innovative weight loss model includes the relationships between orlistat dose, changes in fecal fat excretion, and weight loss, and also incorporates a dropout function. The model guided the dose-finding strategy and allowed simulation of long-term clinical outcomes of orlistat.

  3. Mathematical Modeling of Eddy-Current Loss for a New Induction Heating Device

    Directory of Open Access Journals (Sweden)

    Hai Du

    2014-01-01

    Full Text Available A new induction heating device is presented in this paper. This device can convert mechanical energy into heat energy by utilizing eddy currents, which are induced by rotating permanent magnets. A mathematical model is established for estimating eddy-current loss of the device. The distribution of induced currents and the resultant magnetic field intensity are considered in the process of modeling the eddy-current loss and so is the mutual influence of the electric field between neighborhood pole projection areas. Particularly, the skin effect is considered by correcting the numerical integral domain of eddy current density, which has great effect on the calculating results. Based on specific examples, the effectiveness and correctness of proposed model are proved by finite element analysis. The results show that the mathematical model can provide important reference for design and structure optimization of the device.

  4. QSAR model toward the rational design of new agrochemical fungicides with a defined resistance risk using substructural descriptors.

    Science.gov (United States)

    Speck-Planche, Alejandro; Kleandrova, Valeria V; Rojas-Vargas, Julio A

    2011-11-01

    The increasing resistance of several phytopathogenic fungal species to the existing agrochemical fungicides has alarmed to the worldwide scientific community. There is no available methodology to predict in an efficient way if a new fungicide will have resistance risk due to fungal species which cause considerable crop losses. In an attempt to overcome this problem, a multi-resistance risk QSAR model, based on substructural descriptors was developed from a heterogeneous database of compounds. The purpose of this model is the classification, design, and prediction of agrochemical fungicides according to resistance risk categories. The QSAR model classified correctly 85.11% of the fungicides and the 85.07% of the inactive compounds in the training series, for an accuracy of 85.08%. In the prediction series, the percentages of correct classification were 85.71 and 86.55% for fungicides and inactive compounds, respectively, with an accuracy of 86.39%. Some fragments were extracted and their quantitative contributions to the fungicidal activity were calculated taking into consideration the different resistance risk categories for agrochemical fungicides. In the same way, some fragments present in molecules with fungicidal activity and with negative contributions were analyzed like structural alerts responsible of resistance risk.

  5. Loss of BMP receptor type 1A in murine adipose tissue attenuates age-related onset of insulin resistance.

    Science.gov (United States)

    Schulz, Tim J; Graja, Antonia; Huang, Tian Lian; Xue, Ruidan; An, Ding; Poehle-Kronawitter, Sophie; Lynes, Matthew D; Tolkachov, Alexander; O'Sullivan, Lindsay E; Hirshman, Michael F; Schupp, Michael; Goodyear, Laurie J; Mishina, Yuji; Tseng, Yu-Hua

    2016-08-01

    Adipose tissue dysfunction is a prime risk factor for the development of metabolic disease. Bone morphogenetic proteins (BMPs) have previously been implicated in adipocyte formation. Here, we investigate the role of BMP signalling in adipose tissue health and systemic glucose homeostasis. We employed the Cre/loxP system to generate mouse models with conditional ablation of BMP receptor 1A in differentiating and mature adipocytes, as well as tissue-resident myeloid cells. Metabolic variables were assessed by glucose and insulin tolerance testing, insulin-stimulated glucose uptake and gene expression analysis. Conditional deletion of Bmpr1a using the aP2 (also known as Fabp4)-Cre strain resulted in a complex phenotype. Knockout mice were clearly resistant to age-related impairment of insulin sensitivity during normal and high-fat-diet feeding and showed significantly improved insulin-stimulated glucose uptake in brown adipose tissue and skeletal muscle. Moreover, knockouts displayed significant reduction of variables of adipose tissue inflammation. Deletion of Bmpr1a in myeloid cells had no impact on insulin sensitivity, while ablation of Bmpr1a in mature adipocytes partially recapitulated the initial phenotype from aP2-Cre driven deletion. Co-cultivation of macrophages with pre-adipocytes lacking Bmpr1a markedly reduced expression of proinflammatory genes. Our findings show that altered BMP signalling in adipose tissue affects the tissue's metabolic properties and systemic insulin resistance by altering the pattern of immune cell infiltration. The phenotype is due to ablation of Bmpr1a specifically in pre-adipocytes and maturing adipocytes rather than an immune cell-autonomous effect. Mechanistically, we provide evidence for a BMP-mediated direct crosstalk between pre-adipocytes and macrophages.

  6. Accuracy of cuticular resistance parameterizations in ammonia dry deposition models

    Science.gov (United States)

    Schrader, Frederik; Brümmer, Christian; Richter, Undine; Fléchard, Chris; Wichink Kruit, Roy; Erisman, Jan Willem

    2016-04-01

    Accurate representation of total reactive nitrogen (Nr) exchange between ecosystems and the atmosphere is a crucial part of modern air quality models. However, bi-directional exchange of ammonia (NH3), the dominant Nr species in agricultural landscapes, still poses a major source of uncertainty in these models, where especially the treatment of non-stomatal pathways (e.g. exchange with wet leaf surfaces or the ground layer) can be challenging. While complex dynamic leaf surface chemistry models have been shown to successfully reproduce measured ammonia fluxes on the field scale, computational restraints and the lack of necessary input data have so far limited their application in larger scale simulations. A variety of different approaches to modelling dry deposition to leaf surfaces with simplified steady-state parameterizations have therefore arisen in the recent literature. We present a performance assessment of selected cuticular resistance parameterizations by comparing them with ammonia deposition measurements by means of eddy covariance (EC) and the aerodynamic gradient method (AGM) at a number of semi-natural and grassland sites in Europe. First results indicate that using a state-of-the-art uni-directional approach tends to overestimate and using a bi-directional cuticular compensation point approach tends to underestimate cuticular resistance in some cases, consequently leading to systematic errors in the resulting flux estimates. Using the uni-directional model, situations where low ratios of total atmospheric acids to NH3 concentration occur lead to fairly high minimum cuticular resistances, limiting predicted downward fluxes in conditions usually favouring deposition. On the other hand, the bi-directional model used here features a seasonal cycle of external leaf surface emission potentials that can lead to comparably low effective resistance estimates under warm and wet conditions, when in practice an expected increase in the compensation point due to

  7. Development of Wistar rat model of insulin resistance

    Institute of Scientific and Technical Information of China (English)

    Jing Ai; Ning Wang; Mei Yang; Zhi-Min Du; Yong-Chun Zhang; Bao-Feng Yang

    2005-01-01

    AIM: To establish a simplified and reliable animal model of insulin resistance with low cost in Wistar rats. METHODS: Wistar rats were treated with a high fat emulsion by ig for 10 d. Changes of the diets, drinking and body weight were monitored every day and insulin resistance was evaluated by hyperinsulinemic-euglycemicclamp techniques and short insulin tolerance test using capillary blood glucose. Morphologic changes of liver, fat, skeletal muscles, and pancreatic islets were assessed under light microscope. mRNA expressions of GLUT2 and α-glucosidase in small intestine epithelium, GLUT4 in skeletal muscles and Kir6.2 in beta cell of islets were determined by in situ hybridization.RESULTS: KITT was smaller in treated animals (4.5±0.9)than in untreated control Wistar rats (6.8±1.5), and so was glucose injection rate. Both adipocyte hypertrophy and large pancreatic islets were seen in high fat fed rats,but no changes of skeletal muscles and livers wereobserved. mRNA levels of GLUT2, α-glucosidase in small intestinal epithelium and Kir6.2 mRNA in beta cells of islets increased, whereas that of GLUT4 in skeletal muscles decreased in high fat fed group compared with normal control group.CONCLUSION: An insulin resistance animal model in Wistar rats is established by ig special fat emulsion.

  8. Gag mutations strongly contribute to HIV-1 resistance to protease inhibitors in highly drug-experienced patients besides compensating for fitness loss.

    Directory of Open Access Journals (Sweden)

    Elisabeth Dam

    2009-03-01

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 resistance to protease inhibitors (PI results from mutations in the viral protease (PR that reduce PI binding but also decrease viral replicative capacity (RC. Additional mutations compensating for the RC loss subsequently accumulate within PR and in Gag substrate cleavage sites. We examined the respective contribution of mutations in PR and Gag to PI resistance and RC and their interdependence using a panel of HIV-1 molecular clones carrying different sequences from six patients who had failed multiple lines of treatment. Mutations in Gag strongly and directly contributed to PI resistance besides compensating for fitness loss. This effect was essentially carried by the C-terminal region of Gag (containing NC-SP2-p6 with little or no contribution from MA, CA, and SP1. The effect of Gag on resistance depended on the presence of cleavage site mutations A431V or I437V in NC-SP2-p6 and correlated with processing of the NC/SP2 cleavage site. By contrast, reverting the A431V or I437V mutation in these highly evolved sequences had little effect on RC. Mutations in the NC-SP2-p6 region of Gag can be dually selected as compensatory and as direct PI resistance mutations, with cleavage at the NC-SP2 site behaving as a rate-limiting step in PI resistance. Further compensatory mutations render viral RC independent of the A431V or I437V mutations while their effect on resistance persists.

  9. Use of hybrid discrete cellular models for identification of macroscopic nutrient loss in reaction-diffusion models of tissues.

    Science.gov (United States)

    Aristotelous, Andreas C; Haider, Mansoor A

    2014-08-01

    Macroscopic models accounting for cellular effects in natural or engineered tissues may involve unknown constitutive terms that are highly dependent on interactions at the scale of individual cells. Hybrid discrete models, which represent cells individually, were used to develop and apply techniques for modeling diffusive nutrient transport and cellular uptake to identify a nonlinear nutrient loss term in a macroscopic reaction-diffusion model of the system. Flexible and robust numerical methods were used, based on discontinuous Galerkin finite elements in space and a Crank-Nicolson temporal discretization. Scales were bridged via averaging operations over a complete set of subdomains yielding data for identification of a macroscopic nutrient loss term that was accurately captured via a fifth-order polynomial. Accuracy of the identified macroscopic model was demonstrated by direct, quantitative comparisons of the tissue and cellular scale models in terms of three error norms computed on a mesoscale mesh. Copyright © 2014 John Wiley & Sons, Ltd.

  10. Corresponding decrease in neuronal markers signals progressive parvalbumin neuron loss in MAM schizophrenia model

    OpenAIRE

    Gill, Kathryn M; Grace, Anthony A.

    2014-01-01

    Alteration in normal hippocampal (HPC) function attributed to reduced parvalbumin (PV) expression has been consistently reported in schizophrenia patients and in animal models of schizophrenia. However, it is unclear whether there is an overall loss of interneurons as opposed to a reduction in activity-dependent PV content. Co-expression of PV and the constitutively-expressed substance P (SP)-receptor protein has been utilized in other models to ascertain the degree of cell survival, as oppos...

  11. A lumped element transformer model including core losses and winding impedances

    OpenAIRE

    Ribbenfjärd, David

    2007-01-01

    In order to design a power transformer it is important to understand its internal electromagnetic behaviour. That can be obtained by measurements on physical transformers, analytical expressions and computer simulations. One benefit with simulations is that the transformer can be studied before it is built physically and that the consequences of changing dimensions and parameters easily can be tested. In this thesis a time-domain transformer model is presented. The model includes core losses ...

  12. Beethoven, a mouse model for dominant, progressive hearing loss DFNA36.

    Science.gov (United States)

    Vreugde, Sarah; Erven, Alexandra; Kros, Corné J; Marcotti, Walter; Fuchs, Helmut; Kurima, Kiyoto; Wilcox, Edward R; Friedman, Thomas B; Griffith, Andrew J; Balling, Rudi; Hrabé De Angelis, Martin; Avraham, Karen B; Steel, Karen P

    2002-03-01

    Despite recent progress in identifying genes underlying deafness, there are still relatively few mouse models of specific forms of human deafness. Here we describe the phenotype of the Beethoven (Bth) mouse mutant and a missense mutation in Tmc1 (transmembrane cochlear-expressed gene 1). Progressive hearing loss (DFNA36) and profound congenital deafness (DFNB7/B11) are caused by dominant and recessive mutations of the human ortholog, TMC1 (ref. 1), for which Bth and deafness (dn) are mouse models, respectively.

  13. A guinea pig model of selective severe high-frequency hearing loss.

    Science.gov (United States)

    Havenith, Sarah; Klis, Sjaak F L; Versnel, Huib; Grolman, Wilko

    2013-10-01

    Using an appropriate dose of an aminoglycoside antibiotic cotreated with a loop diuretic a guinea pig model of high-frequency loss can be obtained mimicking cochlear implant candidates with low-frequency residual hearing. We examined the stability of this model over time. A well-established method to create an animal model for profound deafness is cotreatment with an aminoglycoside antibiotic and a loop diuretic. Recent data indicated that reduction of the aminoglycoside dose might yield selective high-frequency hearing loss. Such a model is relevant for studies related to hybrid cochlear implant devices, for example, with respect to preservation of residual hearing. Guinea pigs received an electrode for chronic recording of compound action potentials to tones to assess thresholds. They were treated with a coadministration of kanamycin (200 mg/kg) and furosemide (100 mg/kg), after which, the animals were sacrificed for histologic analysis at 2, 4, or 7 weeks. After 2 to 7 weeks threshold shifts were greater than 50 dB for 8 to 16 kHz in 15 of 17 animals, whereas threshold shifts at 2 kHz or lower were less than 50 dB in 13 animals. Major threshold shifts occurred the first 2 to 4 days; subsequently, some spontaneous recovery occurred and, after 2-3 weeks thresholds, remained stable. Inner hair cell loss still progressed between 2 and 4 weeks in the most basal cochlear region; thereafter, hair cell loss was stable. An appropriate animal model for selective severe high-frequency hearing loss was obtained, which is stable at 4 weeks after ototoxic treatment.

  14. Interference Resistance of Pentamaran Ship Model With Asymmetric Outrigger Configurations

    Institute of Scientific and Technical Information of China (English)

    Yanuar; Ibadurrahman; Kurniawan T. Waskito; S. Karim; M. Ichsan

    2017-01-01

    An experimental investigation is performed to assess the relation of interference performance on the total resistance of a pentamaran model advancing in calm water. For this motivation, the total drag of the ship is performed for several values of asymmetric outrigger configuration and hull separation, altering the Froude number in the range 0.3–0.9. Our results indicate that remarkable changes in resistance require notable changes in transverse distance values (hull separation) when wave interference may occur. In addition, there is no single configuration that consistently outperforms the other configurations across the entire speed range and the optimum interference factor?0.2 appears at a Froude number of 0.45 in S/L=0.33 with the outrigger outer position: asymmetric outboard for A3 configuration.

  15. Body motion in a resistive medium: an exactly solvable model

    Energy Technology Data Exchange (ETDEWEB)

    Molina, M. I. [Universidad de chile, Santiago (Chile)

    2001-04-01

    We introduce and solve in closed form, using momentum and kinetic energy balance, a simplified microscopic model of a body propagating in a one dimensional resistive medium. For a whole family of collisions with varying degree of inelasticities, we find that the effective resistive force on the moving body is opposite to and proportional to the square of the body's velocity. [Spanish] Se plantea y resuelve en forma exacta, usando balance del momentum y energia cinetica, un modelo microscopico simplificado en un cuerpo propagandose en un medio resistivo unidimensional. Para toda una familia de colisiones con diferente grado de inelasticidad, encontramos que la fuerza efectiva sobre el cuerpo es opuesta y proporcional al cuadrado de la velocidad del cuerpo.

  16. Combined heat transfer and kinetic models to predict cooking loss during heat treatment of beef meat.

    Science.gov (United States)

    Kondjoyan, Alain; Oillic, Samuel; Portanguen, Stéphane; Gros, Jean-Bernard

    2013-10-01

    A heat transfer model was used to simulate the temperature in 3 dimensions inside the meat. This model was combined with a first-order kinetic models to predict cooking losses. Identification of the parameters of the kinetic models and first validations were performed in a water bath. Afterwards, the performance of the combined model was determined in a fan-assisted oven under different air/steam conditions. Accurate knowledge of the heat transfer coefficient values and consideration of the retraction of the meat pieces are needed for the prediction of meat temperature. This is important since the temperature at the center of the product is often used to determine the cooking time. The combined model was also able to predict cooking losses from meat pieces of different sizes and subjected to different air/steam conditions. It was found that under the studied conditions, most of the water loss comes from the juice expelled by protein denaturation and contraction and not from evaporation.

  17. Statistical modeling of copper losses in the silicate slag of the sulfide concentrate smelting process

    OpenAIRE

    2015-01-01

    This article presents the results of the statistical modeling of copper losses in the silicate slag of the sulfide concentrates smelting process. The aim of this study was to define the correlation dependence of the degree of copper losses in the silicate slag on the following parameters of technological processes: SiO2, FeO, Fe3O4, CaO and Al2O3 content in the slag and copper content in the matte. Multiple linear regression analysis (MLRA), artificial neural networks (ANNs) and adaptive netw...

  18. Coherence Loss of Two-Photon Jaynes-Cummings Model in Dispersive Approximation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ling; GUO Yan-Qing; SONG He-Shan; LI Chong

    2004-01-01

    Completely solving the dissipative dynamics of nonlinear Jaynes-Cumming model is a very difficult task.In our recent work (Phys. Lett. A284 (2001) 156), we just obtained analytical results of the field dissipative dynamics of the nonlinear JCM. In the present paper, employing the perturbative expansion of master equation, we obtain the density operator of the system (field +atom). The coherence losses of the system and of the atom are investigated when two-photon process is involved. We also study the effect of different atomic initial states and the influence of the field amplitude on the atomic coherence loss.

  19. Applying petrophysical models to radar travel time and electrical resistivity tomograms: Resolution-dependent limitations

    Science.gov (United States)

    Day-Lewis, F. D.; Singha, K.; Binley, A.M.

    2005-01-01

    Geophysical imaging has traditionally provided qualitative information about geologic structure; however, there is increasing interest in using petrophysical models to convert tomograms to quantitative estimates of hydrogeologic, mechanical, or geochemical parameters of interest (e.g., permeability, porosity, water content, and salinity). Unfortunately, petrophysical estimation based on tomograms is complicated by limited and variable image resolution, which depends on (1) measurement physics (e.g., electrical conduction or electromagnetic wave propagation), (2) parameterization and regularization, (3) measurement error, and (4) spatial variability. We present a framework to predict how core-scale relations between geophysical properties and hydrologic parameters are altered by the inversion, which produces smoothly varying pixel-scale estimates. We refer to this loss of information as "correlation loss." Our approach upscales the core-scale relation to the pixel scale using the model resolution matrix from the inversion, random field averaging, and spatial statistics of the geophysical property. Synthetic examples evaluate the utility of radar travel time tomography (RTT) and electrical-resistivity tomography (ERT) for estimating water content. This work provides (1) a framework to assess tomograms for geologic parameter estimation and (2) insights into the different patterns of correlation loss for ERT and RTT. Whereas ERT generally performs better near boreholes, RTT performs better in the interwell region. Application of petrophysical models to the tomograms in our examples would yield misleading estimates of water content. Although the examples presented illustrate the problem of correlation loss in the context of near-surface geophysical imaging, our results have clear implications for quantitative analysis of tomograms for diverse geoscience applications. Copyright 2005 by the American Geophysical Union.

  20. The Ovariectomized Rat as a Model for Studying Alveolar Bone Loss in Postmenopausal Women

    Directory of Open Access Journals (Sweden)

    Bryan D. Johnston

    2015-01-01

    Full Text Available In postmenopausal women, reduced bone mineral density at the hip and spine is associated with an increased risk of tooth loss, possibly due to a loss of alveolar bone. In turn, having fewer natural teeth may lead to compromised food choices resulting in a poor diet that can contribute to chronic disease risk. The tight link between alveolar bone preservation, tooth retention, better nutritional status, and reduced risk of developing a chronic disease begins with the mitigation of postmenopausal bone loss. The ovariectomized rat, a widely used preclinical model for studying postmenopausal bone loss that mimics deterioration of bone tissue in the hip and spine, can also be used to study mineral and structural changes in alveolar bone to develop drug and/or dietary strategies aimed at tooth retention. This review discusses key findings from studies investigating mandible health and alveolar bone in the ovariectomized rat model. Considerations to maximize the benefits of this model are also included. These include the measurement techniques used, the age at ovariectomy, the duration that a rat is studied after ovariectomy and habitual diet consumed.

  1. The Ovariectomized Rat as a Model for Studying Alveolar Bone Loss in Postmenopausal Women

    Science.gov (United States)

    Johnston, Bryan D.; Ward, Wendy E.

    2015-01-01

    In postmenopausal women, reduced bone mineral density at the hip and spine is associated with an increased risk of tooth loss, possibly due to a loss of alveolar bone. In turn, having fewer natural teeth may lead to compromised food choices resulting in a poor diet that can contribute to chronic disease risk. The tight link between alveolar bone preservation, tooth retention, better nutritional status, and reduced risk of developing a chronic disease begins with the mitigation of postmenopausal bone loss. The ovariectomized rat, a widely used preclinical model for studying postmenopausal bone loss that mimics deterioration of bone tissue in the hip and spine, can also be used to study mineral and structural changes in alveolar bone to develop drug and/or dietary strategies aimed at tooth retention. This review discusses key findings from studies investigating mandible health and alveolar bone in the ovariectomized rat model. Considerations to maximize the benefits of this model are also included. These include the measurement techniques used, the age at ovariectomy, the duration that a rat is studied after ovariectomy and habitual diet consumed. PMID:26060817

  2. AC loss of the short coaxial superconducting cable model made from ReBCO coated tapes

    Energy Technology Data Exchange (ETDEWEB)

    Souc, J; Goemoery, F; Vojenciak, M; Frolek, L [Institute of Electrical Engineering., Centre of Excellence CENG, SAS, 841 04 Bratislava (Slovakia); Isfort, D; Ehrenberg, J; Bock, J [Nexans SuperConductors GmbH, Chemiepark Knapsack 50351, Huerth (Germany); Usoskin, A; Rutt, A [EHTS GmbH and Co. KG, Alzenau, (EAS, HANAU) (Germany)], E-mail: eleksouc@savba.sk

    2008-02-15

    Coaxial cable model with both the core as well as the shield conductor made from high-temperature superconducting tapes of the 2nd generation was constructed. AC current was fed to the model of 0.5 m length using a cold core transformer system. The core consists of 14 EHTS YBCO tapes of 4 mm width, and its properties have been published already. Now the system was completed by the shield conductor using 16 ReBCO tapes of 10 mm width produced by Nexans. In this contribution, the properties of the shield conductor are reported in detail. The experimental data on ac transport loss are presented and compared with ac transport loss of the superconducting core. The currents in individual tapes and the total cable current was monitored using Rogowski coils. Significant non-uniformity of the current distribution was found, which is a common issue in short cable models. Therefore, the AC transport loss of the shield conductor was measured by 16 lifted loops placed along the cable, using the averaging method to extract the true loss voltage.

  3. Validation of advanced NSSS simulator model for loss-of-coolant accidents

    Energy Technology Data Exchange (ETDEWEB)

    Kao, S.P.; Chang, S.K.; Huang, H.C. [Nuclear Training Branch, Northeast Utilities, Waterford, CT (United States)

    1995-09-01

    The replacement of the NSSS (Nuclear Steam Supply System) model on the Millstone 2 full-scope simulator has significantly increased its fidelity to simulate adverse conditions in the RCS. The new simulator NSSS model is a real-time derivative of the Nuclear Plant Analyzer by ABB. The thermal-hydraulic model is a five-equation, non-homogeneous model for water, steam, and non-condensible gases. The neutronic model is a three-dimensional nodal diffusion model. In order to certify the new NSSS model for operator training, an extensive validation effort has been performed by benchmarking the model performance against RELAP5/MOD2. This paper presents the validation results for the cases of small-and large-break loss-of-coolant accidents (LOCA). Detailed comparisons in the phenomena of reflux-condensation, phase separation, and two-phase natural circulation are discussed.

  4. Loss Estimation Modeling Of Scenario Lahars From Mount Rainier, Washington State, Using HAZUS-MH

    Science.gov (United States)

    Walsh, T. J.; Cakir, R.

    2011-12-01

    We have adapted lahar hazard zones developed by Hoblitt and others (1998) and converted to digital data by Schilling and others (2008) into the appropriate format for HAZUS-MH, which is FEMA's loss estimation model. We assume that structures engulfed by cohesive lahars will suffer complete loss, and structures affected by post-lahar flooding will be appropriately modeled by the HAZUS-MH flood model. Another approach investigated is to estimate the momentum of lahars, calculate a lateral force, and apply the earthquake model, substituting the lahar lateral force for PGA. Our initial model used the HAZUS default data, which include estimates of building type and value from census data. This model estimated a loss of about 12 billion for a repeat lahar similar to the Electron Mudflow down the Puyallup River. Because HAZUS data are based on census tracts, this estimated damage includes everything in the census tract, even buildings outside of the lahar hazard zone. To correct this, we acquired assessors data from all of the affected counties and converted them into HAZUS format. We then clipped it to the boundaries of the lahar hazard zone to more precisely delineate those properties actually at risk in each scenario. This refined our initial loss estimate to about 6 billion with exclusion of building content values. We are also investigating rebuilding the lahar hazard zones applying Lahar-Z to a more accurate topographic grid derived from recent Lidar data acquired from the Puget Sound Lidar Consortium and Mount Rainier National Park. Final results of these models for the major drainages of Mount Rainier will be posted to the Washington Interactive Geologic Map (http://www.dnr.wa.gov/ResearchScience/Topics/GeosciencesData/Pages/geology_portal.aspx).

  5. On-line iron loss resistance identification by a state observer for rotor-flux-oriented control of induction motor

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, Pablo M. de la; Bossio, Guillermo R.; Garcia, Guillermo O. [Grupo de Electronica Aplicada (GEA), Facultad de Ingenieria, UNRC, Ruta Nacional 36 Km. 601, X5804BYA, Rio Cuarto (Argentina); Solsona, Jorge A. [Instituto de Investigaciones en Ingenieria Electrica ' ' Alfredo Desages' ' , Departamento de Ingenieria Electrica y de Computadoras, UNS, Av. Alem 1253 (8000) Bahia Blanca (Argentina)

    2008-10-15

    A rotor flux state observer considering iron loss, for an Induction Motor (IM), is proposed. The aim of this proposal is to avoid detuning caused by the IM iron loss on a field-oriented control (FOC). An adaptive scheme for the K{sub Fe}, a parameter that represents the IM iron loss, is also proposed. The main objective of this scheme is to improve the dynamic response of control by compensating the variations of iron losses due to possible variations in the stator core characteristics. Simulation results demonstrated that the observer and the adaptive scheme showed a good performance fulfilling then the objectives. (author)

  6. A New Decision Model for Reducing Trim Loss and Inventory in the Paper Industry

    Directory of Open Access Journals (Sweden)

    Fu-Kwun Wang

    2014-01-01

    Full Text Available In the paper industry, numerous studies have explored means of optimizing order allocation and cutting trim loss. However, enterprises may not adopt the resulting solutions because some widths of the inventory exceed or are less than those required for acceptable scheduling. To ensure that the results better suit the actual requirements, we present a new decision model based on the adjustment of scheduling and limitation of inventory quantity to differentiate trim loss and inventory distribution data. Differential analysis is used to reduce data filtering and the information is valuable for decision making. A numerical example is presented to illustrate the applicability of the proposed method. The results show that our proposed method outperforms the manual method regarding scheduling quantity and trim loss.

  7. Mouse models for pendrin-associated loss of cochlear and vestibular function.

    Science.gov (United States)

    Wangemann, Philine

    2013-01-01

    The human gene SLC26A4 and the mouse ortholog Slc26a4 code for the protein pendrin, which is an anion exchanger expressed in apical membranes of selected epithelia. In the inner ear, pendrin is expressed in the cochlea, the vestibular labyrinth and the endolymphatic sac. Loss-of-function and hypo-functional mutations cause an enlargement of the vestibular aqueduct (EVA) and sensorineural hearing loss. The relatively high prevalence of SLC26A4 mutations provides a strong imperative to develop rational interventions that delay, ameliorate or prevent pendrin-associated loss of cochlear and vestibular function. This review summarizes recent studies in mouse models that have been developed to delineate the role of pendrin in the physiology of hearing and balance and that have brought forward the concept that a temporally and spatially limited therapy may be sufficient to secure a life-time of normal hearing in children bearing mutations of SLC26A4.

  8. MATHEMATICAL MODELLING OF OPERATION HEAT NETWORKS IN VIEW OF HEAT LOSS

    Directory of Open Access Journals (Sweden)

    ZBARAZ L. I.

    2016-08-01

    Full Text Available Goal. In recent years, due to a significant rise in price of energy, the reduction of direct costs for heating becomes a priority. In the utilities especially important to optimization of energy heating system equipment. During transport of thermal energy in the distribution networks thermal losses occur along the length of the hydraulic pipes and the coolant pumping losses. These loss-dependence of the particular distribution network. Changing temperature and the hydraulic regime at the source necessary to achieve the minimum cost of transport for today acting tariffs for energy. Scientific novelty. The studies received law changes head to the source at the qualitative and quantitative methods of regulation. Results. A mathematical model of an extensive network of decentralized heat source heating, which are analyzed using different methods of regulating and found the best.

  9. Absolute Determination of Optical Constants by a Direct Physical Modeling of Reflection Electron Energy Loss Spectra

    CERN Document Server

    Xu, H; Toth, J; Tokesi, K; Ding, Z J

    2016-01-01

    We present an absolute extraction method of optical constants of metal from the measured reflection electron energy loss (REELS) spectra by using the recently developed reverse Monte Carlo (RMC) technique. The method is based on a direct physical modeling of electron elastic and electron inelastic scattering near the surface region where the surface excitation becomes important to fully describe the spectrum loss feature intensity in relative to the elastic peak intensity. An optimization procedure of oscillator parameters appeared in the energy loss function (ELF) for describing electron inelastic scattering due to the bulk- and surface-excitations was performed with the simulated annealing method by a successive comparison between the measured and Monte Carlo simulated REELS spectra. The ELF and corresponding optical constants of Fe were obtained from the REELS spectra measured at incident energies of 1000, 2000 and 3000 eV. The validity of the present optical data has been verified with the f- and ps-sum r...

  10. Estimating the Frequency of Horizontal Gene Transfer Using Phylogenetic Models of Gene Gain and Loss.

    Science.gov (United States)

    Zamani-Dahaj, Seyed Alireza; Okasha, Mohamed; Kosakowski, Jakub; Higgs, Paul G

    2016-07-01

    We analyze patterns of gene presence and absence in a maximum likelihood framework with rate parameters for gene gain and loss. Standard methods allow independent gains and losses in different parts of a tree. While losses of the same gene are likely to be frequent, multiple gains need to be considered carefully. A gene gain could occur by horizontal transfer or by origin of a gene within the lineage being studied. If a gene is gained more than once, then at least one of these gains must be a horizontal transfer. A key parameter is the ratio of gain to loss rates, a/v We consider the limiting case known as the infinitely many genes model, where a/v tends to zero and a gene cannot be gained more than once. The infinitely many genes model is used as a null model in comparison to models that allow multiple gains. Using genome data from cyanobacteria and archaea, it is found that the likelihood is significantly improved by allowing for multiple gains, but the average a/v is very small. The fraction of genes whose presence/absence pattern is best explained by multiple gains is only 15% in the cyanobacteria and 20% and 39% in two data sets of archaea. The distribution of rates of gene loss is very broad, which explains why many genes follow a treelike pattern of vertical inheritance, despite the presence of a significant minority of genes that undergo horizontal transfer. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Simplified risk assessment of noise induced hearing loss by means of 2 spreadsheet models.

    Science.gov (United States)

    Lie, Arve; Engdahl, Bo; Tambs, Kristian

    2016-11-18

    The objective of this study has been to test 2 spreadsheet models to compare the observed with the expected hearing loss for a Norwegian reference population. The prevalence rates of the Norwegian and the National Institute for Occupational Safety and Health (NIOSH) definitions of hearing outcomes were calculated in terms of sex and age, 20-64 years old, for a screened (with no occupational noise exposure) (N = 18 858) and unscreened (N = 38 333) Norwegian reference population from the Nord-Trøndelag Hearing Loss Study (NTHLS). Based on the prevalence rates, 2 different spreadsheet models were constructed in order to compare the prevalence rates of various groups of workers with the expected rates. The spreadsheets were then tested on 10 different occupational groups with varying degrees of hearing loss as compared to a reference population. Hearing of office workers, train drivers, conductors and teachers differed little from the screened reference values based on the Norwegian and the NIOSH criterion. The construction workers, miners, farmers and military had an impaired hearing and railway maintenance workers and bus drivers had a mildly impaired hearing. The spreadsheet models give a valid assessment of the hearing loss. The use of spreadsheet models to compare hearing in occupational groups with that of a reference population is a simple and quick method. The results are in line with comparable hearing thresholds, and allow for significance testing. The method is believed to be useful for occupational health services in the assessment of risk of noise induced hearing loss (NIHL) and the preventive potential in groups of noise-exposed workers. Int J Occup Med Environ Health 2016;29(6):991-999.

  12. Simulation Modeling and Analysis of the Impact of Individual Mobility Augmentee Loss at the Tanker Airlift Control Center

    Science.gov (United States)

    2012-06-01

    SIMULATION MODELING AND ANALYSIS OF THE IMPACT OF INDIVIDUAL MOBILITY AUGMENTEE LOSS AT THE TANKER...States Air Force, Department of Defense, or the United States Government. AFIT-OR-MS-ENS-12-18 SIMULATION MODELING AND ANALYSIS OF THE...58 1 SIMULATION MODELING AND ANALYSIS OF THE IMPACT OF INDIVIDUAL MOBILITY AUGMENTEE LOSS AT THE TANKER AIRLIFT CONTROL CENTER I

  13. Carbapenem and cefoxitin resistance of Klebsiella pneumoniae strains associated with porin OmpK36 loss and DHA-1 β-lactamase production.

    Science.gov (United States)

    Shi, Weifeng; Li, Kun; Ji, Yun; Jiang, Qinbo; Wang, Yuyue; Shi, Mei; Mi, Zuhuang

    2013-01-01

    Clinical isolates of carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae) strains are being increased worldwide. Five pan-resistant K. pneumoniae strains have been isolated from respiratory and ICU wards in a Chinese hospital, and reveal strong resistance to all β-lactams, fluoroquinolones and aminoglycosides. Totally 27 β-lactamase genes and 2 membrane pore protein (porin) genes in 5 K. pneumoniae strains were screened by polymerase chain reaction (PCR). The results indicated that all of 5 K. pneumoniae strains carried blaTEM-1 and blaDHA-1 genes, as well as base deletion and mutation of OmpK35 or OmpK36 genes. Compared with carbapenem-sensitive isolates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the resistant isolates markedly lacked the protein band of 34-40 kDa, which might be the outer membrane proteins of OmpK36 according to the electrophoresis mobility. In addition, the conjugation test was confirmed that blaDHA-1 mediated by plasmids could be transferred between resistant and sensitive strains. When reserpine (30 μg/mL) and carbonyl cyanide m-chlorophenylhydrazone (CCCP) (50 μg/mL) were added in imipenem and meropenem, the MICs had no change against K. pneumoniae strains. These results suggest that both DHA-1 β-lactamase and loss or deficiency of porin OmpK36 may be the main reason for the cefoxitin and carbapenem resistance in K. pneumoniae strains in our hospital.

  14. Green tea polyphenols mitigate bone loss of female rats in a chronic inflammation-induced bone loss model

    Science.gov (United States)

    The purpose of this study was to explore bioavailability, efficacy, and molecular mechanisms of green tea polyphenols (GTP) related to preventing bone loss in rats with chronic inflammation. A 2 (placebo vs. lipopolysaccharide, LPS) × 2 (no GTP vs. 0.5% GTP in drinking water) factorial design using ...

  15. Correlation between reduction of superior interventricular groove epicardial fat thickness and improvement of insulin resistance after weight loss in obese men.

    Science.gov (United States)

    Liang, Kae-Woei; Tsai, I-Chen; Lee, Wen-Jane; Lin, Shih-Yi; Lee, Wen-Lieng; Lee, I-Te; Fu, Chia-Po; Wang, Jun-Sing; Sheu, Wayne H-H

    2014-01-01

    It has been recognized that reduction of abdominal visceral fat and subcutaneous fat are associated with improvement in insulin-resistance (IR) after weight loss. However, few studies have investigated the correlation of reduction in epicardial adipose tissue (EAT) with improvement of IR index after weight loss in obese non-diabetic men with metabolic syndrome (MetS). We prospectively enrolled 32 non-diabetic men with MetS for a 3-month weight reduction program mainly by diet control and exercise. Magnetic resonance imaging (MRI) examinations were used to measure EAT, subcutaneous fat, and abdominal visceral fat. Anthropometric parameters, oral glucose tolerance test (OGTT), and serum adipokines were assessed before and after the weight loss program. After a 3-month weight loss program, 27 obese MetS men had significant weight loss >5% (97 ± 14 to 87 ± 14 kg, with a 10.7 % decrease, p fat area (r = -0.673, p = 0.006) were significantly correlated with improvement of OGTT-derived Matsuda insulin-sensitivity index. The decrement ratio of SIVG EAT correlated with improvement of both HOMA-IR and OGTT-derived Matsuda insulin-sensitivity indexes after weight loss in obese non-diabetic men with MetS. (Multi-faceted Evaluations Following Weight Reduction in Subjects with Metabolic Syndrome NCT 01065753 on Feb 8, 2010).

  16. Influence factors of capacity loss after short-time standing of metal-hydride electrode and its EIS model

    Institute of Scientific and Technical Information of China (English)

    王倩楠; 晁栋梁; 周万海; 陈云贵; 吴朝玲

    2013-01-01

    Considerable irreversible capacity loss was observed after the electrode standing at small state-of-charge (SOC) for only a short term. Influence of SOC, standing time and the replacement elements of LaNi5-type hydrogen storage alloys to standing was discussed. Charge-transfer resistance, exchange current density (I0), and hydrogen diffusion coefficient were determined based on the study of electrochemical impedance spectrum (EIS), linear polarization (LP) and constant potential step (CPS), respectively. The oxi-dation of metal Ni on the alloy surface after standing was responsible for the rapid deterioration of capacity, charge-transfer resistance and I0. Galvanostatic, LP, EIS and CPS measurements suggested the presence of an oxide and/or corrosion layer on the alloy surface of raw material and electrode after standing at 0%SOC for 2 d. It was proved that the first small semicircle in high-frequency region of EIS was related to this layer. Novel EIS model in metal hydride electrode was proposed accordingly.

  17. Analytical Model and Characteristics of Current-Observer-Based Induction Motor Speed-Sensorless Vector Control System Taking into Account Iron Loss

    Science.gov (United States)

    Tsuji, Mineo; Xu, Fujin; Tsuruda, Yasutaka; Hamasaki, Shin-Ichi

    We have proposed a current-observer-based speed-sensorless vector control system that is in a rotating reference frame and takes into account iron loss. By deriving a linear model and by computing the trajectories of poles and zeros, the system stability on various parameters such as operating points, observer gain, controller gain and stator resistance has been investigated. Furthermore, an exact analytical model including PWM control, dead time and non-ideal features of power devices is developed. The characteristic improvement and stability limit of the proposed system are discussed by simulation and experiment.

  18. Evolutionary Models of Super-Earths and Mini-Neptunes Incorporating Cooling and Mass Loss

    CERN Document Server

    Howe, Alex R

    2015-01-01

    We construct models of the structural evolution of super-Earth- and mini-Neptune-type exoplanets with hydrogen-helium envelopes, incorporating radiative cooling and XUV-driven mass loss. We conduct a parameter study of these models, focusing on initial mass, radius, and envelope mass fractions, as well as orbital distance, metallicity, and the specific prescription for mass loss. From these calculations, we investigate how the observed masses and radii of exoplanets today relate to the distribution of their initial conditions. Orbital distance and initial envelope mass fraction are the most important factors determining planetary evolution, particular radius evolution. Initial mass also becomes important below a "turnoff mass," which varies with orbital distance, with mass-radius curves being approximately flat for higher masses. Initial radius is the least important parameter we study, with very little difference between the hot start and cold start limits after an age of 100 Myr. Model sets with no mass los...

  19. Status of Computational Aerodynamic Modeling Tools for Aircraft Loss-of-Control

    Science.gov (United States)

    Frink, Neal T.; Murphy, Patrick C.; Atkins, Harold L.; Viken, Sally A.; Petrilli, Justin L.; Gopalarathnam, Ashok; Paul, Ryan C.

    2016-01-01

    A concerted effort has been underway over the past several years to evolve computational capabilities for modeling aircraft loss-of-control under the NASA Aviation Safety Program. A principal goal has been to develop reliable computational tools for predicting and analyzing the non-linear stability & control characteristics of aircraft near stall boundaries affecting safe flight, and for utilizing those predictions for creating augmented flight simulation models that improve pilot training. Pursuing such an ambitious task with limited resources required the forging of close collaborative relationships with a diverse body of computational aerodynamicists and flight simulation experts to leverage their respective research efforts into the creation of NASA tools to meet this goal. Considerable progress has been made and work remains to be done. This paper summarizes the status of the NASA effort to establish computational capabilities for modeling aircraft loss-of-control and offers recommendations for future work.

  20. Numerical models of single- and double-negative metamaterials including viscous and thermal losses

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Sánchez-Dehesa, José

    2017-01-01

    Negative index acoustic metamaterials are artificial structures made of subwavelength units arranged in a lattice, whose effective acoustic parameters, bulk modulus and mass density, can be negative. In these materials, sound waves propagate inside the periodic structure, assumed rigid, showing...... extraordinary properties. We are interested in two particular cases: a double-negative metamaterial, where both parameters are negative at some frequencies, and a single-negative metamaterial with negative bulk modulus within a broader frequency band. In previous research involving the double......-negative metamaterial, numerical models with viscous and thermal losses were used to explain that the extraordinary behavior, predicted by analytical models and numerical simulations with no losses, disappeared when the metamaterial was measured in physical setups. The improvement of the models is allowing now a more...

  1. A mathematical model for the interplay of Nosema infection and forager losses in honey bee colonies.

    Science.gov (United States)

    Petric, Alex; Guzman-Novoa, Ernesto; Eberl, Hermann J

    2016-10-05

    We present a mathematical model (a) for the infection of a honey bee colony with Nosema ceranae. This is a system of five ordinary differential equations for the dependent variables healthy and infected worker bees in the hive, healthy and infected forager bees, and disease potential deposited in the hive. The model is then (b) extended to account for increased forager losses, e.g. caused by exposure to external stressors. The model is non-autonomous with periodic coefficient functions. Algebraic complexity prevents a rigorous mathematical analysis. Therefore, we resort to computer simulations in addition to some analytical results in the constant coefficient case. We investigate each of the two stressors (a) and (b) individually and jointly. Our results indicate that the combined effect of two stressors, both of which can be tolerated by the colony individually, might lead to colony failure, suggesting multi-factorial causes behind losses of honey bee colonies.

  2. Statistical modeling of copper losses in the silicate slag of the sulfide concentrate smelting process

    Directory of Open Access Journals (Sweden)

    Savic Marija V.

    2015-09-01

    Full Text Available This article presents the results of the statistical modeling of copper losses in the silicate slag of the sulfide concentrates smelting process. The aim of this study was to define the correlation dependence of the degree of copper losses in the silicate slag on the following parameters of technological processes: SiO2, FeO, Fe3O4, CaO and Al2O3 content in the slag and copper content in the matte. Multiple linear regression analysis (MLRA, artificial neural networks (ANNs and adaptive network based fuzzy inference system (ANFIS were used as tools for mathematical analysis of the indicated problem. The best correlation coefficient (R2 = 0.719 of the final model was obtained using the ANFIS modeling approach.

  3. Model predictive control of non-linear systems over networks with data quantization and packet loss.

    Science.gov (United States)

    Yu, Jimin; Nan, Liangsheng; Tang, Xiaoming; Wang, Ping

    2015-11-01

    This paper studies the approach of model predictive control (MPC) for the non-linear systems under networked environment where both data quantization and packet loss may occur. The non-linear controlled plant in the networked control system (NCS) is represented by a Tagaki-Sugeno (T-S) model. The sensed data and control signal are quantized in both links and described as sector bound uncertainties by applying sector bound approach. Then, the quantized data are transmitted in the communication networks and may suffer from the effect of packet losses, which are modeled as Bernoulli process. A fuzzy predictive controller which guarantees the stability of the closed-loop system is obtained by solving a set of linear matrix inequalities (LMIs). A numerical example is given to illustrate the effectiveness of the proposed method.

  4. A simple model for predicting sprint-race times accounting for energy loss on the curve

    Science.gov (United States)

    Mureika, J. R.

    1997-11-01

    The mathematical model of J. Keller for predicting World Record race times, based on a simple differential equation of motion, predicted quite well the records of the day. One of its shortcoming is that it neglects to account for a sprinter's energy loss around a curve, a most important consideration particularly in the 200m--400m. An extension to Keller's work is considered, modeling the aforementioned energy loss as a simple function of the centrifugal force acting on the runner around the curve. Theoretical World Record performances for indoor and outdoor 200m are discussed, and the use of the model at 300m is investigated. Some predictions are made for possible 200m outdoor and indoor times as run by Canadian 100m WR holder Donovan Bailey, based on his 100m final performance at the 1996 Olympic Games in Atlanta.

  5. A Simple Model for Predicting Sprint Race Times Accounting for Energy Loss on the Curve

    CERN Document Server

    Mureika, J R

    1997-01-01

    The mathematical model of J. Keller for predicting World Record race times, based on a simple differential equation of motion, predicted quite well the records of the day. One of its shortcoming is that it neglects to account for a sprinter's energy loss around a curve, a most important consideration particularly in the 200m--400m. An extension to Keller's work is considered, modeling the aforementioned energy loss as a simple function of the centrifugal force acting on the runner around the curve. Theoretical World Record performances for indoor and outdoor 200m are discussed, and the use of the model at 300m is investigated. Some predictions are made for possible 200m outdoor and indoor times as run by Canadian 100m WR holder Donovan Bailey, based on his 100m final performance at the 1996 Olympic Games in Atlanta.

  6. Impact of Loss Synchronization on Reliable High Speed Networks: A Model Based Simulation

    Directory of Open Access Journals (Sweden)

    Suman Kumar

    2014-01-01

    Full Text Available Contemporary nature of network evolution demands for simulation models which are flexible, scalable, and easily implementable. In this paper, we propose a fluid based model for performance analysis of reliable high speed networks. In particular, this paper aims to study the dynamic relationship between congestion control algorithms and queue management schemes, in order to develop a better understanding of the causal linkages between the two. We propose a loss synchronization module which is user configurable. We validate our model through simulations under controlled settings. Also, we present a performance analysis to provide insights into two important issues concerning 10 Gbps high speed networks: (i impact of bottleneck buffer size on the performance of 10 Gbps high speed network and (ii impact of level of loss synchronization on link utilization-fairness tradeoffs. The practical impact of the proposed work is to provide design guidelines along with a powerful simulation tool to protocol designers and network developers.

  7. Modeling relationships between water table depth and peat soil carbon loss in Southeast Asian plantations

    Science.gov (United States)

    Carlson, Kimberly M.; Goodman, Lael K.; May-Tobin, Calen C.

    2015-07-01

    Plantation-associated drainage of Southeast Asian peatlands has accelerated in recent years. Draining exposes the upper peat layer to oxygen, leading to elevated decomposition rates and net soil carbon losses. Empirical studies indicate positive relationships between long-term water table (WT) depth and soil carbon loss rate in peatlands. These correlations potentially enable using WT depth as a proxy for soil carbon losses from peatland plantations. Here, we compile data from published research assessing WT depth and carbon balance in tropical plantations on peat. We model net carbon loss from subsidence studies, as well as soil respiration (heterotrophic and total) from closed chamber studies, as a function of WT depth. WT depth across all 12 studies and 59 sites is 67 ± 20 cm (mean ± standard deviation). Mean WT depth is positively related to net carbon loss, as well as soil respiration rate. Our models explain 45% of net carbon loss variation and 45-63% of soil respiration variation. At a 70 cm WT depth, the subsidence model suggests net carbon loss of 20 tC ha-1 yr-1 (95% confidence interval (CI) 18-22 tC ha-1 yr-1) for plantations drained for >2 yr. Closed chamber-measured total soil respiration at this depth is 20 tC-CO2 ha-1 yr-1 (CI 17-24 tC-CO2 ha-1 yr-1) while heterotrophic respiration is 17 tC-CO2 ha-1 yr-1 (CI 14-20 tC-CO2 ha-1 yr-1), ˜82% of total respiration. While land use is not a significant predictor of soil respiration, WT depths are greater at acacia (75 ± 16 cm) than oil palm (59 ± 15 cm) sample sites. Improved spatio-temporal sampling of the full suite of peat soil carbon fluxes—including fluvial carbon export and organic fertilizer inputs—will clarify multiple mechanisms leading to carbon loss and gain, supporting refined assessments of the global warming potential of peatland drainage.

  8. ATLS Hypovolemic Shock Classification by Prediction of Blood Loss in Rats Using Regression Models.

    Science.gov (United States)

    Choi, Soo Beom; Choi, Joon Yul; Park, Jee Soo; Kim, Deok Won

    2016-07-01

    In our previous study, our input data set consisted of 78 rats, the blood loss in percent as a dependent variable, and 11 independent variables (heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse pressure, respiration rate, temperature, perfusion index, lactate concentration, shock index, and new index (lactate concentration/perfusion)). The machine learning methods for multicategory classification were applied to a rat model in acute hemorrhage to predict the four Advanced Trauma Life Support (ATLS) hypovolemic shock classes for triage in our previous study. However, multicategory classification is much more difficult and complicated than binary classification. We introduce a simple approach for classifying ATLS hypovolaemic shock class by predicting blood loss in percent using support vector regression and multivariate linear regression (MLR). We also compared the performance of the classification models using absolute and relative vital signs. The accuracies of support vector regression and MLR models with relative values by predicting blood loss in percent were 88.5% and 84.6%, respectively. These were better than the best accuracy of 80.8% of the direct multicategory classification using the support vector machine one-versus-one model in our previous study for the same validation data set. Moreover, the simple MLR models with both absolute and relative values could provide possibility of the future clinical decision support system for ATLS classification. The perfusion index and new index were more appropriate with relative changes than absolute values.

  9. Loss-of-function rodent models for parkin and PINK1.

    Science.gov (United States)

    Oliveras-Salvá, Marusela; Van Rompuy, Anne-Sophie; Heeman, Bavo; Van den Haute, Chris; Baekelandt, Veerle

    2011-01-01

    Parkinson's disease is a common neurodegenerative disorder whose aetiology is not yet fully understood. In the past ten years, the discovery of genes linked to hereditary forms of the disease has impelled the development of animal models. These should lead to the identification of novel pathways that provide insight into the functionality of the proteins involved and the pathogenesis of the sporadic forms of the disease. In particular, loss-of-function mutations in the parkin and PINK1 (phosphatase and tensin homolog (PTEN)-induced kinase 1) genes account for most of the cases of familial autosomal recessive parkinsonism. Both parkin and PINK1 knockout rodent models are now available, which display an overall mild phenotype consisting of a mitochondrial dysfunction together with changes in dopamine metabolism and oxidative stress. However, up till now these models fail to reproduce the main hallmarks of Parkinson's disease: the dopaminergic cell loss in the substantia nigra and the presence of cytoplasmic inclusions, named Lewy bodies, in the remaining dopaminergic neurons. We here review the most important knockout and knockdown rodent models generated so far for these two recessive Parkinson's disease-causing genes. We critically feature their main characteristics and their impact on the research field, and propose some future directions for the study and modelling of the loss of function of parkin and PINK1 in rodents.

  10. AC transport current loss in a coated superconductor in the Bean model

    Energy Technology Data Exchange (ETDEWEB)

    Carr, W.J. [LEI, 700 Technology Drive, Pittsburgh, PA 15219 (United States)]. E-mail: wjamescarrjr@att.net

    2004-10-15

    A new and straightforward calculation is made of the loss in a very thin superconducting strip of rectangular cross-section (e.g. the coating on a coated superconductor) carrying ac transport current in zero applied magnetic field, with a similar strip acting as the return path. The computation is made assuming only that the strip is composed of uniform material which obeys Maxwell's equations and the Bean model. An important consequence of the Bean model is the existence of a field-free region about the middle of the superconductor cross-section. The present loss calculation is novel in two respects: (1) It uses for the first time an actual computation of the shape of the field-free region rather than using qualitative assumptions, and (2) it uses a new approach for making the loss calculation, based on a rigorous solution of Maxwell's equations for this problem. The rigorous solution correctly treats the problem as three-dimensional, having a time-dependent charge on the surface of the superconductor, and having the electric field described by both a vector and a scalar potential. Loss computations are made for the ratio of peak current to critical current in the approximate range of one-half to one, where within this range the loss decreases by about two powers of 10. The most important result coming out of the present calculation (made for the case of a distant return path large compared with the conductor cross-section dimensions but small compared with the length of the conductor), is a confirmation of Norris's previously estimated loss expression which he obtained in a different way.

  11. Mass loss from OH/IR stars - Models for the infrared emission of circumstellar dust shells

    Science.gov (United States)

    Justtanont, K.; Tielens, A. G. G. M.

    1992-01-01

    The IR emission of a sample of 24 OH/IR stars is modeled, and the properties of circumstellar dust and mass-loss rate of the central star are derived. It is shown that for some sources the observations of the far-IR emission is well fitted with a lambda exp -1 law, while some have a steeper index of 1.5. For a few sources, the presence of circumstellar ice grains is inferred from detailed studies of the observed 10-micron feature. Dust mass-loss rates are determined from detailed studies for all the stars in this sample. They range from 6.0 x 10 exp -10 solar mass/yr for an optically visible Mira to 2.2 x 10 exp -6 solar mass/yr for a heavily obscured OH/IR star. These dust mass-loss rates are compared to those calculated from IRAS photometry using 12-, 25-, and 60-micron fluxes. The dust mass-loss rates are also compared to gas mass-loss rates determined from OH and CO observations. For stars with tenuous shells, a dust-to-gas ratio of 0.001 is obtained.

  12. Localized Retroprocessing as a Model of Intron Loss in the Plant Mitochondrial Genome.

    Science.gov (United States)

    Cuenca, Argelia; Ross, T Gregory; Graham, Sean W; Barrett, Craig F; Davis, Jerrold I; Seberg, Ole; Petersen, Gitte

    2016-08-03

    Loss of introns in plant mitochondrial genes is commonly explained by retroprocessing. Under this model, an mRNA is reverse transcribed and integrated back into the genome, simultaneously affecting the contents of introns and edited sites. To evaluate the extent to which retroprocessing explains intron loss, we analyzed patterns of intron content and predicted RNA editing for whole mitochondrial genomes of 30 species in the monocot order Alismatales. In this group, we found an unusually high degree of variation in the intron content, even expanding the hitherto known variation among angiosperms. Some species have lost some two-third of the cis-spliced introns. We found a strong correlation between intron content and editing frequency, and detected 27 events in which intron loss is consistent with the presence of nucleotides in an edited state, supporting retroprocessing. However, we also detected seven cases of intron loss not readily being explained by retroprocession. Our analyses are also not consistent with the entire length of a fully processed cDNA copy being integrated into the genome, but instead indicate that retroprocessing usually occurs for only part of the gene. In some cases, several rounds of retroprocessing may explain intron loss in genes completely devoid of introns. A number of taxa retroprocessing seem to be very common and a possibly ongoing process. It affects the entire mitochondrial genome.

  13. Spatial modeling for estimation of earthquakes economic loss in West Java

    Science.gov (United States)

    Retnowati, Dyah Ayu; Meilano, Irwan; Riqqi, Akhmad; Hanifa, Nuraini Rahma

    2017-07-01

    Indonesia has a high vulnerability towards earthquakes. The low adaptive capacity could make the earthquake become disaster that should be concerned. That is why risk management should be applied to reduce the impacts, such as estimating the economic loss caused by hazard. The study area of this research is West Java. The main reason of West Java being vulnerable toward earthquake is the existence of active faults. These active faults are Lembang Fault, Cimandiri Fault, Baribis Fault, and also Megathrust subduction zone. This research tries to estimates the value of earthquakes economic loss from some sources in West Java. The economic loss is calculated by using HAZUS method. The components that should be known are hazard (earthquakes), exposure (building), and the vulnerability. Spatial modeling is aimed to build the exposure data and make user get the information easier by showing the distribution map, not only in tabular data. As the result, West Java could have economic loss up to 1,925,122,301,868,140 IDR ± 364,683,058,851,703.00 IDR, which is estimated from six earthquake sources with maximum possibly magnitude. However, the estimation of economic loss value in this research is the worst case earthquakes occurrence which is probably over-estimated.

  14. Mass loss from OH/IR stars - Models for the infrared emission of circumstellar dust shells

    Science.gov (United States)

    Justtanont, K.; Tielens, A. G. G. M.

    1992-01-01

    The IR emission of a sample of 24 OH/IR stars is modeled, and the properties of circumstellar dust and mass-loss rate of the central star are derived. It is shown that for some sources the observations of the far-IR emission is well fitted with a lambda exp -1 law, while some have a steeper index of 1.5. For a few sources, the presence of circumstellar ice grains is inferred from detailed studies of the observed 10-micron feature. Dust mass-loss rates are determined from detailed studies for all the stars in this sample. They range from 6.0 x 10 exp -10 solar mass/yr for an optically visible Mira to 2.2 x 10 exp -6 solar mass/yr for a heavily obscured OH/IR star. These dust mass-loss rates are compared to those calculated from IRAS photometry using 12-, 25-, and 60-micron fluxes. The dust mass-loss rates are also compared to gas mass-loss rates determined from OH and CO observations. For stars with tenuous shells, a dust-to-gas ratio of 0.001 is obtained.

  15. Distributions of hafnia and titania cores in EUV metal resists evaluated by scanning transmission electron microscopy and electron energy loss spectroscopy

    Science.gov (United States)

    Toriumi, Minoru; Sato, Yuta; Koshino, Masanori; Suenaga, Kazu; Itani, Toshiro

    2016-11-01

    The morphologies of hafnia (HfO x ) and titania (TiO x ) cores and their distributions in metal resists for EUV lithography were characterized at the atomic level by scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS). The HfO x cores show a higher affinity to organic components, such as methacrylic acid and benzoic acid, than the TiO x cores, and the same core-shell state as in a solution is almost completely maintained in the HfO x resist film. Furthermore, it was found that the surface modification of the TiO x cores by silylation is effective for preventing their aggregation and improves the postcoating delay (PCD) of the resist.

  16. Relationship between Pulmonary Airflow and Resistance in Patients with Airway Narrowing Using An 1-D Network Resistance and Compliance Model

    Science.gov (United States)

    Choi, Sanghun; Choi, Jiwoong; Hoffman, Eric; Lin, Ching-Long

    2016-11-01

    To predict the proper relationship between airway resistance and regional airflow, we proposed a novel 1-D network model for airway resistance and acinar compliance. First, we extracted 1-D skeletons at inspiration images, and generated 1-D trees of CT unresolved airways with a volume filling method. We used Horsfield order with random heterogeneity to create diameters of the generated 1-D trees. We employed a resistance model that accounts for kinetic energy and viscous dissipation (Model A). The resistance model is further coupled with a regional compliance model estimated from two static images (Model B). For validation, we applied both models to a healthy subject. The results showed that Model A failed to provide airflows consistent with air volume change, whereas Model B provided airflows consistent with air volume change. Since airflows shall be regionally consistent with air volume change in patients with normal airways, Model B was validated. Then, we applied Model B to severe asthmatic subjects. The results showed that regional airflows were significantly deviated from air volume change due to airway narrowing. This implies that airway resistance plays a major role in determining regional airflows of patients with airway narrowing. Support for this study was provided, in part, by NIH Grants U01 HL114494, R01 HL094315, R01 HL112986, and S10 RR022421.

  17. Modelling proteins' hidden conformations to predict antibiotic resistance

    Science.gov (United States)

    Hart, Kathryn M.; Ho, Chris M. W.; Dutta, Supratik; Gross, Michael L.; Bowman, Gregory R.

    2016-10-01

    TEM β-lactamase confers bacteria with resistance to many antibiotics and rapidly evolves activity against new drugs. However, functional changes are not easily explained by differences in crystal structures. We employ Markov state models to identify hidden conformations and explore their role in determining TEM's specificity. We integrate these models with existing drug-design tools to create a new technique, called Boltzmann docking, which better predicts TEM specificity by accounting for conformational heterogeneity. Using our MSMs, we identify hidden states whose populations correlate with activity against cefotaxime. To experimentally detect our predicted hidden states, we use rapid mass spectrometric footprinting and confirm our models' prediction that increased cefotaxime activity correlates with reduced Ω-loop flexibility. Finally, we design novel variants to stabilize the hidden cefotaximase states, and find their populations predict activity against cefotaxime in vitro and in vivo. Therefore, we expect this framework to have numerous applications in drug and protein design.

  18. Adaptation to the cost of resistance: a model of compensation, recombination, and selection in a haploid organism

    OpenAIRE

    Wijngaarden, Pieter J.; van den Bosch, Frank; Jeger, Michael J.; Rolf F Hoekstra

    2004-01-01

    Populations of pathogenic organisms often evolve resistance in response to the use of pesticides or antibiotics. This rise of resistance may be followed by a fall when chemical control is suspended and resistance alleles carry a fitness cost. Another possibility is that mutations at secondary loci compensate for the cost, usually without loss of resistance. This enables resistant types to withstand invasion by the susceptible wild-type; resistance then persists in the population, which reduce...

  19. The Effects of Revealed Information on Catastrophe Loss Projection Models' Characterization of Risk: Damage Vulnerability Evidence from Florida.

    Science.gov (United States)

    Karl, J Bradley; Medders, Lorilee A; Maroney, Patrick F

    2016-06-01

    We examine whether the risk characterization estimated by catastrophic loss projection models is sensitive to the revelation of new information regarding risk type. We use commercial loss projection models from two widely employed modeling firms to estimate the expected hurricane losses of Florida Atlantic University's building stock, both including and excluding secondary information regarding hurricane mitigation features that influence damage vulnerability. We then compare the results of the models without and with this revealed information and find that the revelation of additional, secondary information influences modeled losses for the windstorm-exposed university building stock, primarily evidenced by meaningful percent differences in the loss exceedance output indicated after secondary modifiers are incorporated in the analysis. Secondary risk characteristics for the data set studied appear to have substantially greater impact on probable maximum loss estimates than on average annual loss estimates. While it may be intuitively expected for catastrophe models to indicate that secondary risk characteristics hold value for reducing modeled losses, the finding that the primary value of secondary risk characteristics is in reduction of losses in the "tail" (low probability, high severity) events is less intuitive, and therefore especially interesting. Further, we address the benefit-cost tradeoffs that commercial entities must consider when deciding whether to undergo the data collection necessary to include secondary information in modeling. Although we assert the long-term benefit-cost tradeoff is positive for virtually every entity, we acknowledge short-term disincentives to such an effort. © 2015 Society for Risk Analysis.

  20. The evolution of massive stars including mass loss - Presupernova models and explosion

    Science.gov (United States)

    Woosley, S. E.; Langer, Norbert; Weaver, Thomas A.

    1993-01-01

    The evolution of massive stars of 35, 40, 60, and 85 solar masses is followed through all stages of nuclear burning to the point of Fe core collapse. Critical nuclear reaction and mass-loss rates are varied. Efficient mass loss during the Wolf-Rayet (WR) stage is likely to lead to final masses as small as 4 solar masses. For a reasonable parameterization of the mass loss, there may be convergence of all WR stars, both single and in binaries, to a narrow band of small final masses. Our representative model, a 4.25 solar-mass WR presupernova derived from a 60 solar mass star, is followed through a simulated explosion, and its explosive nucleosynthesis and light curve are determined. Its properties are similar to those observed in Type Ib supernovae. The effects of the initial mass and mass loss on the presupernova structure of small mass WR models is also explored. Important properties of the presupernova star and its explosion can only be obtained by following the complete evolution starting on the main sequence.

  1. Efficient Location Uncertainty Treatment for Probabilistic Modelling of Portfolio Loss from Earthquake Events

    Science.gov (United States)

    Scheingraber, Christoph; Käser, Martin; Allmann, Alexander

    2017-04-01

    Probabilistic seismic risk analysis (PSRA) is a well-established method for modelling loss from earthquake events. In the insurance industry, it is widely employed for probabilistic modelling of loss to a distributed portfolio. In this context, precise exposure locations are often unknown, which results in considerable loss uncertainty. The treatment of exposure uncertainty has already been identified as an area where PSRA would benefit from increased research attention. However, so far, epistemic location uncertainty has not been in the focus of a large amount of research. We propose a new framework for efficient treatment of location uncertainty. To demonstrate the usefulness of this novel method, a large number of synthetic portfolios resembling real-world portfolios is systematically analyzed. We investigate the effect of portfolio characteristics such as value distribution, portfolio size, or proportion of risk items with unknown coordinates on loss variability. Several sampling criteria to increase the computational efficiency of the framework are proposed and put into the wider context of well-established Monte-Carlo variance reduction techniques. The performance of each of the proposed criteria is analyzed.

  2. The evolution of massive stars including mass loss - Presupernova models and explosion

    Science.gov (United States)

    Woosley, S. E.; Langer, Norbert; Weaver, Thomas A.

    1993-01-01

    The evolution of massive stars of 35, 40, 60, and 85 solar masses is followed through all stages of nuclear burning to the point of Fe core collapse. Critical nuclear reaction and mass-loss rates are varied. Efficient mass loss during the Wolf-Rayet (WR) stage is likely to lead to final masses as small as 4 solar masses. For a reasonable parameterization of the mass loss, there may be convergence of all WR stars, both single and in binaries, to a narrow band of small final masses. Our representative model, a 4.25 solar-mass WR presupernova derived from a 60 solar mass star, is followed through a simulated explosion, and its explosive nucleosynthesis and light curve are determined. Its properties are similar to those observed in Type Ib supernovae. The effects of the initial mass and mass loss on the presupernova structure of small mass WR models is also explored. Important properties of the presupernova star and its explosion can only be obtained by following the complete evolution starting on the main sequence.

  3. Classifying human audiometric phenotypes of age-related hearing loss from animal models.

    Science.gov (United States)

    Dubno, Judy R; Eckert, Mark A; Lee, Fu-Shing; Matthews, Lois J; Schmiedt, Richard A

    2013-10-01

    Age-related hearing loss (presbyacusis) has a complex etiology. Results from animal models detailing the effects of specific cochlear injuries on audiometric profiles may be used to understand the mechanisms underlying hearing loss in older humans and predict cochlear pathologies associated with certain audiometric configurations ("audiometric phenotypes"). Patterns of hearing loss associated with cochlear pathology in animal models were used to define schematic boundaries of human audiograms. Pathologies included evidence for metabolic, sensory, and a mixed metabolic + sensory phenotype; an older normal phenotype without threshold elevation was also defined. Audiograms from a large sample of older adults were then searched by a human expert for "exemplars" (best examples) of these phenotypes, without knowledge of the human subject demographic information. Mean thresholds and slopes of higher frequency thresholds of the audiograms assigned to the four phenotypes were consistent with the predefined schematic boundaries and differed significantly from each other. Significant differences in age, gender, and noise exposure history provided external validity for the four phenotypes. Three supervised machine learning classifiers were then used to assess reliability of the exemplar training set to estimate the probability that newly obtained audiograms exhibited one of the four phenotypes. These procedures classified the exemplars with a high degree of accuracy; classifications of the remaining cases were consistent with the exemplars with respect to average thresholds and demographic information. These results suggest that animal models of age-related hearing loss can be used to predict human cochlear pathology by classifying audiograms into phenotypic classifications that reflect probable etiologies for hearing loss in older humans.

  4. Swept-sine noise-induced damage as a hearing loss model for preclinical assays

    Directory of Open Access Journals (Sweden)

    Lorena eSanz

    2015-02-01

    Full Text Available Mouse models are key tools for studying cochlear alterations in noise-induced hearing loss and for evaluating new therapies. Stimuli used to induce deafness in mice are usually white and octave band noises that include very low frequencies, considering the large mouse auditory range. We designed different sound stimuli, enriched in frequencies up to 20 kHz (violet noises to examine their impact on hearing thresholds and cochlear cytoarchitecture after short exposure. In addition, we developed a cytocochleogram to quantitatively assess the ensuing structural degeneration and its functional correlation. Finally, we used this mouse model and cochleogram procedure to evaluate the potential therapeutic effect of transforming growth factor β1 inhibitors P17 and P144 on noise-induced hearing loss. CBA mice were exposed to violet swept-sine noise with different frequency ranges (2-20 or 9-13 kHz and levels (105 or 120 dB SPL for 30 minutes. Mice were evaluated by auditory brainstem response and otoacoustic emission tests prior to and 2, 14 and 28 days after noise exposure. Cochlear pathology was assessed with gross histology; hair cell number was estimated by a stereological counting method. Our results indicate that functional and morphological changes induced by violet swept-sine noise depend on the sound level and frequency composition. Partial hearing recovery followed the exposure to 105 dB SPL, whereas permanent cochlear damage resulted from the exposure to 120 dB SPL. Exposure to 9-13 kHz noise caused an auditory threshold shift in those frequencies that correlated with hair cell loss in the corresponding areas of the cochlea that were spotted on the cytocochleogram. In summary, we present mouse models of noise-induced hearing loss, which depending on the sound properties of the noise, cause different degrees of cochlear damage, and could therefore be used to study molecules which are potential players in hearing loss protection and repair.

  5. On high heels and short muscles: a multiscale model for sarcomere loss in the gastrocnemius muscle.

    Science.gov (United States)

    Zöllner, Alexander M; Pok, Jacquelynn M; McWalter, Emily J; Gold, Garry E; Kuhl, Ellen

    2015-01-21

    High heels are a major source of chronic lower limb pain. Yet, more than one third of all women compromise health for looks and wear high heels on a daily basis. Changing from flat footwear to high heels induces chronic muscle shortening associated with discomfort, fatigue, reduced shock absorption, and increased injury risk. However, the long-term effects of high-heeled footwear on the musculoskeletal kinematics of the lower extremities remain poorly understood. Here we create a multiscale computational model for chronic muscle adaptation to characterize the acute and chronic effects of global muscle shortening on local sarcomere lengths. We perform a case study of a healthy female subject and show that raising the heel by 13cm shortens the gastrocnemius muscle by 5% while the Achilles tendon remains virtually unaffected. Our computational simulation indicates that muscle shortening displays significant regional variations with extreme values of 22% in the central gastrocnemius. Our model suggests that the muscle gradually adjusts to its new functional length by a chronic loss of sarcomeres in series. Sarcomere loss varies significantly across the muscle with an average loss of 9%, virtually no loss at the proximal and distal ends, and a maximum loss of 39% in the central region. These changes reposition the remaining sarcomeres back into their optimal operating regime. Computational modeling of chronic muscle shortening provides a valuable tool to shape our understanding of the underlying mechanisms of muscle adaptation. Our study could open new avenues in orthopedic surgery and enhance treatment for patients with muscle contracture caused by other conditions than high heel wear such as paralysis, muscular atrophy, and muscular dystrophy.

  6. Experimental modeling of injectivity loss; Modelagem experimental da perda de injetividade

    Energy Technology Data Exchange (ETDEWEB)

    Bonato, Adriano Jose do Amaral Mello; Silva, Pedro Glauto de Farias e; Gomes, Vanessa Limeira Azevedo; Santos, Adriano dos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2012-07-01

    Produced water reinjection, suspended particles are retained in the porous media causing formation damage and injectivity decline. In general the retention of the particles occurs near the side of injection, this fact occurs in most cases, due to the size exclusion. The modeling of filtration and the consequent formation damage is essential to the project management of water injection in oil reservoirs. Thus, mathematical models are studied to better predict the distribution of particles throughout the porous media and determine the parameters of adjustment to injectivity decline. Among these models, there is the classic model which consists in determining these parameters (coefficient of filtration and formation damage). The methodology used in modeling is given from the equations the mass conservation, kinetic particle retention, the modified Darcy equation and the function formation damage. This study aimed to improve experimental modeling, including development of software for acquisition and processing of experimental data, considering the variable number of pressure measurements along the sample. The software was developed using the Labview 2011 platform and allows the determination of relevant parameters to predict injectivity loss in water injection wells. Furthermore, based on the traditional model of filtration in porous media (including depth filtration and formation of the external plaster), the software was applied to predict injectivity loss in addition to the properties of the grout. Finally, the classical models for transporting suspensions and damage to the formation were observed. (author)

  7. Skeletal muscle atrogene expression and insulin resistance in a rat model of polytrauma.

    Science.gov (United States)

    Akscyn, Robert M; Franklin, John L; Gavrikova, Tatyana A; Messina, Joseph L

    2016-02-01

    Polytrauma is a combination of injuries to more than one body part or organ system. Polytrauma is common in warfare, and in automobile and industrial accidents. The combination of injuries can include burn, fracture, hemorrhage, and trauma to the extremities or specific organ systems. Resistance to anabolic hormones, loss of muscle mass, and metabolic dysfunction can occur following injury. To investigate the effects of combined injuries, we have developed a highly reproducible rodent model of polytrauma. This model combines burn injury, soft tissue trauma, and penetrating injury to the gastrointestinal (GI) tract. Adult, male Sprague-Dawley rats were anesthetized with pentobarbital and subjected to a 15-20% total body surface area scald burn, or laparotomy and a single puncture of the cecum with a G30 needle, or the combination of both injuries (polytrauma). In the current studies, the inflammatory response to polytrauma was examined in skeletal muscle. Changes in skeletal muscle mRNA levels of the proinflammatory cytokines TNF-α, IL-1β, and IL-6 were observed following single injuries and polytrauma. Increased expression of the E3 ubiquitin ligases Atrogin-1/FBX032 and TRIM63/MuRF-1 were measured following injury, as was skeletal muscle insulin resistance, as evidenced by decreased insulin-inducible insulin receptor (IR) and AKT/PKB (Protein Kinase B) phosphorylation. Changes in the abundance of IR and insulin receptor substrate-1 (IRS-1) were observed at the protein and mRNA levels. Additionally, increased TRIB3 mRNA levels were observed 24 h following polytrauma, the same time when insulin resistance was observed. This may suggest a role for TRIB3 in the development of acute insulin resistance following injury.

  8. Estimating tag loss of the Atlantic Horseshoe crab, Limulus polyphemus, using a multi-state model

    Science.gov (United States)

    Butler, Catherine Alyssa; McGowan, Conor P.; Grand, James B.; Smith, David

    2012-01-01

    The Atlantic Horseshoe crab, Limulus polyphemus, is a valuable resource along the Mid-Atlantic coast which has, in recent years, experienced new management paradigms due to increased concern about this species role in the environment. While current management actions are underway, many acknowledge the need for improved and updated parameter estimates to reduce the uncertainty within the management models. Specifically, updated and improved estimates of demographic parameters such as adult crab survival in the regional population of interest, Delaware Bay, could greatly enhance these models and improve management decisions. There is however, some concern that difficulties in tag resighting or complete loss of tags could be occurring. As apparent from the assumptions of a Jolly-Seber model, loss of tags can result in a biased estimate and underestimate a survival rate. Given that uncertainty, as a first step towards estimating an unbiased estimate of adult survival, we first took steps to estimate the rate of tag loss. Using data from a double tag mark-resight study conducted in Delaware Bay and Program MARK, we designed a multi-state model to allow for the estimation of mortality of each tag separately and simultaneously.

  9. Theory of dielectric loss in Graphene-on-substrate: A tight- binding model study

    Science.gov (United States)

    Sahu, Sivabrata; Panda, S. K.; Rout, G. C.

    2016-09-01

    Graphene-on-substrate exhibits interesting dielectric behaviour due to screening of coulomb interaction induced by many body effects. In this communication we attempt to study the dielectric loss property of graphene within tight-binding model approach. The Hamiltonian consisting of electron hopping upto third-nearest-neighbour's with impurities in two in equivalent sub-lattices. The graphene-on-substrate raises the energy +Δ at one sub lattice and reduces energy -Δ at other sub lattice. Further we introduced coulomb interaction between π - electrons at the two sub lattices separately with the same effective coulomb interaction. We calculate polarization function Π(q, ω) which is a two particle Green's function arising due to charge-charge correlation by using Zubarev's Green's function technique. Finally we calculate dielectric function of graphene i.e. ε(q, ω) =1+Π(q,ω) at arbitrary wave vector q and frequency ra. The dielectric loss in graphene calculated from the imaginary part of dielectric function which is a measure of absorption spectrum. Only a few Fragmentary theoretical attempts have been made to utilize the full frequency and wave vector dependent dielectric function. We compute numerically the frequency dependent dielectric loss function for 100x100 momentum grid points. We observe a low energy Plasmon resonance peak and a high energy flat peak arising due to absorption of optical energy at substrate induced gap. With increase of small Plasmon wave vector, both low and high energy peaks approach each other. The dielectric loss at low energies exhibits a parabolic curve, but it exhibit a clear peak on introduction of higher order electron hopping's. The Coulomb interaction suppresses induced gap in graphene and decreases the optical energy absorption spectra. The increase of substrate induced gap shifts the high energy flat peak to higher energies and enhances the dielectric loss throughout the frequency range. Finally the effect of doping on

  10. The functional age of hearing loss in a mouse model of presbycusis. I. Behavioral assessments.

    Science.gov (United States)

    Prosen, Cynthia A; Dore, Dawn J; May, Bradford J

    2003-09-01

    Presbycusis is a common form of hearing loss that progresses from high to low frequencies with advancing age. C57BL/6J mice experience a rapid progression of presbycusis-like hearing deficits and thus provide a convenient animal model for evaluating behavioral, physiological and anatomical correlates of the disorder. Previous studies of C57BL/6J mice have relied on short-term observations of age-matched subject groups to reconstruct a time course for auditory pathologies. Such statistical approaches are weakened by the variability of hearing thresholds in young mice and the inconsistent timing of degenerative effects in older mice. The present study was designed to resolve these ambiguities by tracking the hearing abilities of individual C57BL/6J mice from age 16 weeks until the onset of hearing loss in specific listening conditions. Testing at frequencies of 8 and 16 kHz in quiet confirmed the high-to-low frequency progression that is characteristic of presbycusis. Often the hearing loss developed in two phases, one gradual and the other abrupt. Testing in noise revealed deficits that were first manifested as threshold instability and then an increased susceptibility to masking. These changes occurred before hearing loss in quiet. CBA/CaJ mice did not show significant loss during a similar period of observation. Our findings provide a well-ordered chronology for isolating the functional consequences of multiple cochlear pathologies that arise during the time course of presbycusis. This neurobehavioral assessment is termed the functional age of hearing loss. Neuroanatomical assessments of behaviorally characterized C57BL/6J mice are presented in the companion paper [Hear. Res. 183 (2003) 29-36].

  11. Modeling the effect of reflective calf hutch covers on reducing heat loss

    Science.gov (United States)

    Binion, W. R.; Friend, T. H.

    2015-12-01

    This study determined if a reflective film could theoretically be useful in moderating the rate of heat loss from calves housed in polyethylene hutches during cold weather. An engineering approach was used in which rate of heat loss was modeled using 38-l steel drums filled with body temperature water and covered by fresh calf hide. The reflective film (cover) consisted of aluminized 0.0635 mm low-density olive color polyethylene. The non-reflective olive side was sprayed with flat black paint. Covers were 1.8 × 3 m with the aluminized side facing the hutch. Two of four hutches were either uncovered or had covers across the top and sides. During the night, (mean temperature ± SE -13.6 ± 0.29 °C), the rate of temperature loss was -0.21 °C per 5-min interval over 28 temperature readings in the covered and -0.25 °C in the uncovered ( R 2 = 0.99). During the daytime (mean ± SE 14.3 ± 0.52 °C), rate of heat loss was -0.15 °C per 5-min interval over 33 temperature readings in the covered and -0.11 °C in the uncovered ( R 2 = 0.99). Reflective film reduced the rate of heat loss during cold nights, but when the sun was shining on the hutches during midday, the uncovered hutches warmed up more and, hence, reduced the rate of heat loss when compared to the covered. Further research is needed on the orientation of hutches in relationship to the sun and with live calves because calves would be able to move into the sun during cold sunny days.

  12. Life stage and resistance effects in modelling phosphine fumigation of Rhyzopertha dominica (F.)

    OpenAIRE

    Thorne, J.; Fulford, G.; Ridley, A.; Schlipalius, D.; P. Collins

    2010-01-01

    Resistance to phosphine in insect pests of stored grain is a serious problem and there is a world-wide need for the development of sustainable resistance management strategies. Here we introduce results from a new mathematical model of resistance development that includes all life stages, rates of oviposition, natural mortality and mortality under fumigation in relation to resistant genotype. The example we discuss is phosphine resistance in the lesser grain borer, Rhyzopertha dominica where ...

  13. Hilar somatostatin interneuron loss reduces dentate gyrus inhibition in a mouse model of temporal lobe epilepsy.

    Science.gov (United States)

    Hofmann, Gabrielle; Balgooyen, Laura; Mattis, Joanna; Deisseroth, Karl; Buckmaster, Paul S

    2016-06-01

    In patients with temporal lobe epilepsy, seizures usually start in the hippocampus, and dentate granule cells are hyperexcitable. Somatostatin interneurons are a major subpopulation of inhibitory neurons in the dentate gyrus, and many are lost in patients and animal models. However, surviving somatostatin interneurons sprout axon collaterals and form new synapses, so the net effect on granule cell inhibition remains unclear. The present study uses optogenetics to activate hilar somatostatin interneurons and measure the inhibitory effect on dentate gyrus perforant path-evoked local field potential responses in a mouse model of temporal lobe epilepsy. In controls, light activation of hilar somatostatin interneurons inhibited evoked responses up to 40%. Epileptic pilocarpine-treated mice exhibited loss of hilar somatostatin interneurons and less light-induced inhibition of evoked responses. These findings suggest that severe epilepsy-related loss of hilar somatostatin interneurons can overwhelm the surviving interneurons' capacity to compensate by sprouting axon collaterals. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

  14. Development of a river ice jam by a combined heat loss and hydraulic model

    Science.gov (United States)

    Eliasson, J.; Gröndal, G. O.

    2008-11-01

    The heat loss theory and the hydraulic theory for the analysis of the development of wide channel ice jams are discussed and shown. The heat loss theory has been used in Iceland for a long time, while the hydraulic theory largely follows the classical ice-jam build-up theories used in known CFD models. The results are combined in a new method to calculate the maximum thickness and the extent of an ice jam. The results compare favorably to the HEC-RAS model for the development of a very large ice jam in Thjorsa River in Iceland, and have been found in good agreement with historical data, collected where a hydroelectric dam project, Urridafoss, is being planned in the Thjorsa River.

  15. New expected loss impairment model – a challenge for the banks in Bulgaria

    Directory of Open Access Journals (Sweden)

    Nadezhda Popova-Yosifova

    2017-05-01

    Full Text Available This article introduces some of the leading works on loan impairment published by supervisory authorities, auditing companies and researchers. It makes analysis of the impairment model on the basis of the expected credit losses introduced with the requirements of International Financial Reporting Standard (IFRS 9 Financial Instruments effective for periods beginning on or after 1 January 2018. There are a number of research works which show that the senior bankers may in some ways manage the financial result through the impairment, where it is assumed that the new impairment model will bring higher recognized losses. It also makes a comparative analysis of the announced information on the loan impairment and the preparation for the introduction of the IFRS 9 Financial Instruments requirements into the annual financial statements of the public banks in Bulgaria for the period 2013 – 2016.

  16. Development of a river ice jam by a combined heat loss and hydraulic model

    Directory of Open Access Journals (Sweden)

    J. Eliasson

    2008-11-01

    Full Text Available The heat loss theory and the hydraulic theory for the analysis of the development of wide channel ice jams are discussed and shown. The heat loss theory has been used in Iceland for a long time, while the hydraulic theory largely follows the classical ice-jam build-up theories used in known CFD models. The results are combined in a new method to calculate the maximum thickness and the extent of an ice jam. The results compare favorably to the HEC-RAS model for the development of a very large ice jam in Thjorsa River in Iceland, and have been found in good agreement with historical data, collected where a hydroelectric dam project, Urridafoss, is being planned in the Thjorsa River.

  17. Hidden Markov Model-based Packet Loss Concealment for Voice over IP

    DEFF Research Database (Denmark)

    Rødbro, Christoffer A.; Murthi, Manohar N.; Andersen, Søren Vang

    2006-01-01

    As voice over IP proliferates, packet loss concealment (PLC) at the receiver has emerged as an important factor in determining voice quality of service. Through the use of heuristic variations of signal and parameter repetition and overlap-add interpolation to handle packet loss, conventional PLC...... systems largely ignore the dynamics of the statistical evolution of the speech signal, possibly leading to perceptually annoying artifacts. To address this problem, we propose the use of hidden Markov models for PLC. With a hidden Markov model (HMM) tracking the evolution of speech signal parameters, we...... demonstrate how PLC is performed within a statistical signal processing framework. Moreover, we show how the HMM is used to index a specially designed PLC module for the particular signal context, leading to signal-contingent PLC. Simulation examples, objective tests, and subjective listening tests...

  18. Loss of protection with insecticide-treated nets against pyrethroid-resistant Culex quinquefasciatus mosquitoes once nets become holed: an experimental hut study

    Directory of Open Access Journals (Sweden)

    Irish SR

    2008-06-01

    Full Text Available Abstract Background An important advantage of pyrethroid-treated nets over untreated nets is that once nets become worn or holed a pyrethroid treatment will normally restore protection. The capacity of pyrethroids to kill or irritate any mosquito that comes into contact with the net and prevent penetration of holes or feeding through the sides are the main reasons why treated nets continue to provide protection despite their condition deteriorating over time. Pyrethroid resistance is a growing problem among Anopheline and Culicine mosquitoes in many parts of Africa. When mosquitoes become resistant the capacity of treated nets to provide protection might be diminished, particularly when holed. An experimental hut trial against pyrethroid-resistant Culex quinquefasciatus was therefore undertaken in southern Benin using a series of intact and holed nets, both untreated and treated, to assess any loss of protection as nets deteriorate with use and time. Results There was loss of protection when untreated nets became holed; the proportion of mosquitoes blood feeding increased from 36.2% when nets were intact to between 59.7% and 68.5% when nets were holed to differing extents. The proportion of mosquitoes blood feeding when treated nets were intact was 29.4% which increased to 43.6–57.4% when nets were holed. The greater the number of holes the greater the loss of protection regardless of whether nets were untreated or treated. Mosquito mortality in huts with untreated nets was 12.9–13.6%; treatment induced mortality was less than 12%. The exiting rate of mosquitoes into the verandas was higher in huts with intact nets. Conclusion As nets deteriorate with use and become increasingly holed the capacity of pyrethroid treatments to restore protection is greatly diminished against resistant Culex quinquefasciatus mosquitoes.

  19. Weight loss on low-fat vs. low-carbohydrate diets by insulin resistance status among overweight adults and adults with obesity: A randomized pilot trial.

    Science.gov (United States)

    Gardner, Christopher D; Offringa, Lisa C; Hartle, Jennifer C; Kapphahn, Kris; Cherin, Rise

    2016-01-01

    To test for differential weight loss response to low-fat (LF) vs. low-carbohydrate (LC) diets by insulin resistance status with emphasis on overall quality of both diets. Sixty-one adults, BMI 28-40 kg/m(2) , were randomized in a 2 × 2 design to LF or LC by insulin resistance status in this pilot study. Primary outcome was 6-month weight change. Participants were characterized as more insulin resistant (IR) or more insulin sensitive (IS) by median split of baseline insulin-area-under-the-curve from an oral glucose tolerance test. Intervention consisted of 14 one-hour class-based educational sessions. Baseline % carbohydrate:% fat:% protein was 44:38:18. At 6 months, the LF group reported 57:21:22 and the LC group reported 22:53:25 (IR and IS combined). Six-month weight loss (kg) was 7.4 ± 6.0 (LF-IR), 10.4 ± 7.8 (LF-IS), 9.6 ± 6.6 (LC-IR), and 8.6 ± 5.6 (LC-IS). No significant main effects were detected for weight loss by diet group or IR status; there was no significant diet × IR interaction. Significant differences in several secondary outcomes were observed. Substantial weight loss was achieved overall, but a significant diet × IR status interaction was not observed. Opportunity to detect differential response may have been limited by the focus on high diet quality for both diet groups and sample size. © 2015 The Obesity Society.

  20. Index models to evaluate the risk of phosphorus and nitrogen loss at catchment scales.

    Science.gov (United States)

    Drewry, J J; Newham, L T H; Greene, R S B

    2011-03-01

    This paper investigates index models as a tool to estimate the risk of N and P source strengths and loss at the catchment scale. The index models assist managers in improving the focus of remediation actions that reduce nutrient delivery to waterbodies. N and P source risk factors (e.g. soil nutrient concentrations) and transport risk factors (e.g. distance-to-streams) are used to determine the overall risk of nutrient loss for a case study in the Tuross River catchment of coastal southeast Australia. In the development of the N index model for Tuross, particulate N was considered important based on the observed event water quality data. In contrast to previous N index models, erosion and contributing distance were therefore included in the Tuross River catchment N index. Event-based water quality monitoring, and soil information, or in data-poor catchments conceptual understanding, are essential to represent catchment-scale processes. The techniques have high applicability in other catchments, and are complementary to other modelling techniques such as process-based semi-distributed modelling. Index models generally provide much more detailed spatial resolution than fully- or semi-distributed conceptual modelling approaches. Semi-distributed models can be used to quantify nutrient loads and provide overall direction to set the broad focus of management. Index models can then be used to refine on-the-ground investigations and investment priorities. In this way semi-distributed models can be combined with index models to provide a set of powerful tools to influence management decisions and outcomes. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Loss model for off-design performance analysis of radial turbines with pivoting-vane, variable-area stators

    Science.gov (United States)

    Meitner, P. L.; Glassman, A. J.

    1980-01-01

    An off-design performance loss model for a radial turbine with pivoting, variable-area stators is developed through a combination of analytical modeling and experimental data analysis. A viscous loss model is used for the variation in stator loss with setting angle, and stator vane end-clearance leakage effects are predicted by a clearance flow model. The variation of rotor loss coefficient with stator setting angle is obtained by means of an analytical matching of experimental data for a rotor that was tested with six stators, having throat areas from 20 to 144% of the design area. An incidence loss model is selected to obtain best agreement with experimental data. The stator vane end-clearance leakage model predicts increasing mass flow and decreasing efficiency as a result of end-clearances, with changes becoming significantly larger with decreasing stator area.

  2. Loss model for off-design performance analysis of radial turbines with pivoting-vane, variable-area stators

    Science.gov (United States)

    Meitner, P. L.; Glassman, A. J.

    1980-01-01

    An off-design performance loss model for a radial turbine with pivoting, variable-area stators is developed through a combination of analytical modeling and experimental data analysis. A viscous loss model is used for the variation in stator loss with setting angle, and stator vane end-clearance leakage effects are predicted by a clearance flow model. The variation of rotor loss coefficient with stator setting angle is obtained by means of an analytical matching of experimental data for a rotor that was tested with six stators, having throat areas from 20 to 144% of the design area. An incidence loss model is selected to obtain best agreement with experimental data. The stator vane end-clearance leakage model predicts increasing mass flow and decreasing efficiency as a result of end-clearances, with changes becoming significantly larger with decreasing stator area.

  3. Model atmospheres with periodic shocks. [pulsations and mass loss in variable stars

    Science.gov (United States)

    Bowen, G. H.

    1989-01-01

    The pulsation of a long-period variable star generates shock waves which dramatically affect the structure of the star's atmosphere and produce conditions that lead to rapid mass loss. Numerical modeling of atmospheres with periodic shocks is being pursued to study the processes involved and the evolutionary consequences for the stars. It is characteristic of these complex dynamical systems that most effects result from the interaction of various time-dependent processes.

  4. The reversibility of sea ice loss in a state-of-the-art climate model

    OpenAIRE

    Armour, K. C.; Eisenman, I; Blanchard-Wrigglesworth, E.; McCusker, K. E.; Bitz, C.M.

    2011-01-01

    Rapid Arctic sea ice retreat has fueled speculation about the possibility of threshold (or ‘tipping point’) behavior and irreversible loss of the sea ice cover. We test sea ice reversibility within a state-of-the-art atmosphere–ocean global climate model by increasing atmospheric carbon dioxide until the Arctic Ocean becomes ice-free throughout the year and subsequently decreasing it until the initial ice cover returns. Evidence for irreversibility in the form of hysteresis outside the envelo...

  5. Model atmospheres with periodic shocks. [pulsations and mass loss in variable stars

    Science.gov (United States)

    Bowen, G. H.

    1989-01-01

    The pulsation of a long-period variable star generates shock waves which dramatically affect the structure of the star's atmosphere and produce conditions that lead to rapid mass loss. Numerical modeling of atmospheres with periodic shocks is being pursued to study the processes involved and the evolutionary consequences for the stars. It is characteristic of these complex dynamical systems that most effects result from the interaction of various time-dependent processes.

  6. Computational modeling of drug-resistant bacteria. Final report

    Energy Technology Data Exchange (ETDEWEB)

    MacDougall, Preston [Middle Tennessee State Univ., Murfreesboro, TN (United States)

    2015-03-12

    Initial proposal summary: The evolution of antibiotic-resistant mutants among bacteria (superbugs) is a persistent and growing threat to public health. In many ways, we are engaged in a war with these microorganisms, where the corresponding arms race involves chemical weapons and biological targets. Just as advances in microelectronics, imaging technology and feature recognition software have turned conventional munitions into smart bombs, the long-term objectives of this proposal are to develop highly effective antibiotics using next-generation biomolecular modeling capabilities in tandem with novel subatomic feature detection software. Using model compounds and targets, our design methodology will be validated with correspondingly ultra-high resolution structure-determination methods at premier DOE facilities (single-crystal X-ray diffraction at Argonne National Laboratory, and neutron diffraction at Oak Ridge National Laboratory). The objectives and accomplishments are summarized.

  7. Retinol-Binding Protein 4 and Its Relation to Insulin Resistance in Obese Children before and after Weight Loss

    OpenAIRE

    Reinehr, Thomas; Stoffel-Wagner, Birgit; Roth, Christian L.

    2008-01-01

    Context: There are limited and controversial data concerning the relationships between retinol-binding protein 4 (RBP4), weight status, and insulin resistance in obese humans and especially in children.

  8. Use of Transition Modeling to Enable the Computation of Losses for Variable-Speed Power Turbine

    Science.gov (United States)

    Ameri, Ali A.

    2012-01-01

    To investigate the penalties associated with using a variable speed power turbine (VSPT) in a rotorcraft capable of vertical takeoff and landing, various analysis tools are required. Such analysis tools must be able to model the flow accurately within the operating envelope of VSPT. For power turbines low Reynolds numbers and a wide range of the incidence angles, positive and negative, due to the variation in the shaft speed at relatively fixed corrected flows, characterize this envelope. The flow in the turbine passage is expected to be transitional and separated at high incidence. The turbulence model of Walters and Leylek was implemented in the NASA Glenn-HT code to enable a more accurate analysis of such flows. Two-dimensional heat transfer predictions of flat plate flow and two-dimensional and three-dimensional heat transfer predictions on a turbine blade were performed and reported herein. Heat transfer computations were performed because it is a good marker for transition. The final goal is to be able to compute the aerodynamic losses. Armed with the new transition model, total pressure losses for three-dimensional flow of an Energy Efficient Engine (E3) tip section cascade for a range of incidence angles were computed in anticipation of the experimental data. The results obtained form a loss bucket for the chosen blade.

  9. THE ROLE OF DIFFERENT RHEOLOGICAL MODELS IN ACCURACY OF PRESSURE LOSS PREDICTION

    Directory of Open Access Journals (Sweden)

    Katarina Simon

    2004-12-01

    Full Text Available Hydraulics play an important function in many oil field operations including drilling, completion, fracturing, acidizing, workover and production. The standard API methods for drilling fluid hydraulics assume either power law or Bingham plastic rheological model. These models and corresponding hydraulic calculations do provide a simple way for fair estimates of hydraulics for conventional vertical wells using simple drilling fluids, such as bentonite fluids. However, nowdays with many wells drilled deep, slim or horizontal using complex muds with unusual behaviour (such as tested MMH mud, it is necessary to use appropriate rheological model for mathematical modelling of fluid behaviour. Oil and gas reservoirs in Croatia have been under production for quite a while and the probability to discover new deposits of hydrocarbons is rather small. Therefore attempts have been made to maintain the gas and oil exploitation at the present level. One of possible ways to meet this target is re-entry wells drilling. The diameter of such wells in reservoir is smaller than 0,1524 m (6 in. Accurate modelling of annular pressure losses becomes therefore an important issue, particularly in cases where a small safety margin exists between optimal drilling parameters and wellbore stability, what is the case in re-entry wells. The objective of the paper is to show the influence of well geometry and accuracy of fluid rheological properties modelling to the distribution of pressure losses in a slimhole well.

  10. Modelling of labour productivity loss due to climate change: HEAT-SHIELD

    Science.gov (United States)

    Kjellstrom, Tord; Daanen, Hein

    2016-04-01

    Climate change will bring higher heat levels (temperature and humidity combined) to large parts of the world. When these levels reach above thresholds well defined by human physiology, the ability to maintain physical activity levels decrease and labour productivity is reduced. This impact is of particular importance in work situations in areas with long high intensity hot seasons, but also affects cooler areas during heat waves. Our modelling of labour productivity loss includes climate model data of the Inter-Sectoral Impact Model Inter-comparison Project (ISI-MIP), calculations of heat stress indexes during different months, estimations of work capacity loss and its annual impacts in different parts of the world. Different climate models will be compared for the Representative Concentration Pathways (RCPs) and the outcomes of the 2015 Paris Climate Conference (COP21) agreements. The validation includes comparisons of modelling outputs with actual field studies using historical heat data. These modelling approaches are a first stage contribution to the European Commission funded HEAT-SHIELD project.

  11. Comprehensive flood economic losses: review of the potential damage and implementation of an agricultural impact model

    Directory of Open Access Journals (Sweden)

    Mao Gwladys

    2016-01-01

    Full Text Available With an annual loss averaging 580 M€ between 1990 and 2014, floods are the main natural catastrophe (Nat Cat risk for the French Nat Cat compensation scheme. As part of its role in this scheme, the Caisse Centrale de Réassurance (CCR offers state guaranteed reinsurance programs and has been modelling the risk of flooding since 2003. This model is based on the traditional valuation approach of direct tangible costs which pairs a physical model with exposure through damage curves. CCR wishes now to widen the studied damage scope to insured and noninsured economic costs and has been collaborating with the SAF research laboratory from the Institute of Financial and Insurance Sciences (ISFA since 2014. CCR’s model has been used to estimate the insured direct damage to residential and non-residential properties and it is now being developed to include damage to vehicles, agriculture and network infrastructures. Research is also being carried out to take into account business interruptions and indirect losses using an Input-Output model. This article describes the undergoing work on model development to estimate the damage to agriculture.

  12. Complement and microglia mediate early synapse loss in Alzheimer mouse models.

    Science.gov (United States)

    Hong, Soyon; Beja-Glasser, Victoria F; Nfonoyim, Bianca M; Frouin, Arnaud; Li, Shaomin; Ramakrishnan, Saranya; Merry, Katherine M; Shi, Qiaoqiao; Rosenthal, Arnon; Barres, Ben A; Lemere, Cynthia A; Selkoe, Dennis J; Stevens, Beth

    2016-05-06

    Synapse loss in Alzheimer's disease (AD) correlates with cognitive decline. Involvement of microglia and complement in AD has been attributed to neuroinflammation, prominent late in disease. Here we show in mouse models that complement and microglia mediate synaptic loss early in AD. C1q, the initiating protein of the classical complement cascade, is increased and associated with synapses before overt plaque deposition. Inhibition of C1q, C3, or the microglial complement receptor CR3 reduces the number of phagocytic microglia, as well as the extent of early synapse loss. C1q is necessary for the toxic effects of soluble β-amyloid (Aβ) oligomers on synapses and hippocampal long-term potentiation. Finally, microglia in adult brains engulf synaptic material in a CR3-dependent process when exposed to soluble Aβ oligomers. Together, these findings suggest that the complement-dependent pathway and microglia that prune excess synapses in development are inappropriately activated and mediate synapse loss in AD. Copyright © 2016, American Association for the Advancement of Science.

  13. Loss of hippocampal interneurons and epileptogenesis: a comparison of two animal models of acquired epilepsy.

    Science.gov (United States)

    Huusko, Noora; Römer, Christine; Ndode-Ekane, Xavier Ekolle; Lukasiuk, Katarzyna; Pitkänen, Asla

    2015-01-01

    Reduced hippocampal GABAergic inhibition is acknowledged to be associated with epilepsy. However, there are no studies that had quantitatively compared the loss of various interneuron populations in different models of epilepsy. We tested a hypothesis that the more severe the loss of hippocampal interneurons, the more severe was the epilepsy. Epileptogenesis was triggered in adult rats by status epilepticus (SE) (56 SE, 24 controls) or by traumatic brain injury (TBI) (45 TBI, 23 controls). The total number of hippocampal parvalbumin (PARV), cholecystokinin (CCK), calretinin (CR), somatostatin (SOM), or neuropeptide Y (NPY) positive neurons was estimated using unbiased stereology at 1 or 6 months post-insult. The rats with TBI had no spontaneous seizures but showed increased seizure susceptibility. Eleven of the 28 rats (39 %) in the SE group had spontaneous seizures. The most affected hippocampal area after TBI was the ipsilateral dentate gyrus, where 62 % of PARV-immunoreactive (ir) (p loss was substantially more severe, widespread, progressive, and included more interneuron subclasses after TBI than after SE. Interneurons responsible for perisomatic inhibition were more vulnerable to TBI than those providing dendritic inhibition. Unlike expected, we could not demonstrate any etiology-independent link between the severity of hippocampal interneuron loss and the overall risk of spontaneous seizures.

  14. A new multiscale modeling method for simulating the loss processes in polymer solar cell nanodevices

    Science.gov (United States)

    Pershin, Anton; Donets, Sergii; Baeurle, Stephan A.

    2012-05-01

    The photoelectric power conversion efficiency of polymer solar cells is till now, compared to conventional inorganic solar cells, still relatively low with maximum values ranging from 7% to 8%. This essentially relates to the existence of exciton and charge carrier loss phenomena, reducing the performance of polymer solar cells significantly. In this paper we introduce a new computer simulation technique, which permits to explore the causes of the occurrence of such phenomena at the nanoscale and to design new photovoltaic materials with optimized opto-electronic properties. Our approach consists in coupling a mesoscopic field-theoretic method with a suitable dynamic Monte Carlo algorithm, to model the elementary photovoltaic processes. Using this algorithm, we investigate the influence of structural characteristics and different device conditions on the exciton generation and charge transport efficiencies in case of a novel nanostructured polymer blend. More specifically, we find that the disjunction of continuous percolation paths leads to the creation of dead ends, resulting in charge carrier losses through charge recombination. Moreover, we observe that defects are characterized by a low exciton dissociation efficiency due to a high charge accumulation, counteracting the charge generation process. From these observations, we conclude that both the charge carrier loss and the exciton loss phenomena lead to a dramatic decrease in the internal quantum efficiency. Finally, by analyzing the photovoltaic behavior of the nanostructures under different circuit conditions, we demonstrate that charge injection significantly determines the impact of the defects on the solar cell performance.

  15. Calorie-restricted weight loss reverses high-fat diet-induced ghrelin resistance, which contributes to rebound weight gain in a ghrelin-dependent manner.

    Science.gov (United States)

    Briggs, Dana I; Lockie, Sarah H; Wu, Qunli; Lemus, Moyra B; Stark, Romana; Andrews, Zane B

    2013-02-01

    Twelve weeks of high-fat diet feeding causes ghrelin resistance in arcuate neuropeptide Y (NPY)/agouti-related protein (AgRP) neurons. In the current study, we investigated whether diet-induced weight loss could restore NPY/AgRP neuronal responsiveness to ghrelin and whether ghrelin mediates rebound weight gain after calorie-restricted (CR) weight loss. Diet-induced obese (DIO) mice were allocated to one of two dietary interventions until they reached the weight of age-matched lean controls. DIO mice received chow diet ad libitum or chow diet with 40% CR. Chow-fed and high-fat-fed mice served as controls. Both dietary interventions normalized body weight, glucose tolerance, and plasma insulin. We show that diet-induced weight loss with CR increases total plasma ghrelin, restores ghrelin sensitivity, and increases hypothalamic NPY and AgRP mRNA expression. We propose that long-term DIO creates a higher body weight set-point and that weight loss induced by CR, as seen in the high-fat CR group, provokes the brain to protect the new higher set-point. This adaptation to weight loss likely contributes to rebound weight gain by increasing peripheral ghrelin concentrations and restoring the function of ghrelin-responsive neuronal populations in the hypothalamic arcuate nucleus. Indeed, we also show that DIO ghrelin-knockout mice exhibit reduced body weight regain after CR weight loss compared with ghrelin wild-type mice, suggesting ghrelin mediates rebound weight gain after CR weight loss.

  16. Modelling the interactions between regional farming structure, nitrogen losses and environmental regulation

    DEFF Research Database (Denmark)

    Happe, Kathrin; Hutchings, Nick; Dalgaard, Tommy;

    2011-01-01

    Changes in the structure of agriculture are known to affect emissions of environmental pollutants from agriculture. Such changes are often driven by structural changes in agricultural production, so structural changes are likely to have indirect effects on emissions. In a pilot study, we consider...... how linking two complementary simulation models might be used to explore these effects. The agent-based AgriPoliS model was used to simulate the structural dynamics of agricultural production. The results from AgriPoliS were passed via a number of intermediate models to the Farm-N model, which...... was used to estimate the nitrogen surplus and losses from each farm for each year. The modelling complex was exercised by simulating the effects of two plausible policy scenarios for each of 14 years. The initial sizes and types of farms were based on statistics from a region in Denmark and the farms were...

  17. Fully-coupled magnetoelastic model for Galfenol alloys incorporating eddy current losses and thermal relaxation

    Science.gov (United States)

    Evans, Phillip G.; Dapino, Marcelo J.

    2008-03-01

    A general framework is developed to model the nonlinear magnetization and strain response of cubic magnetostrictive materials to 3-D dynamic magnetic fields and 3-D stresses. Dynamic eddy current losses and inertial stresses are modeled by coupling Maxwell's equations to Newton's second law through a nonlinear constitutive model. The constitutive model is derived from continuum thermodynamics and incorporates rate-dependent thermal effects. The framework is implemented in 1-D to describe a Tonpilz transducer in both dynamic actuation and sensing modes. The model is shown to qualitatively describe the effect of increase in magnetic hysteresis with increasing frequency, the shearing of the magnetization loops with increasing stress, and the decrease in the magnetostriction with increasing load stiffness.

  18. Predicting the loss of phylogenetic diversity under non-stationary diversification models.

    Science.gov (United States)

    Lambert, Amaury; Steel, Mike

    2013-11-21

    For many species, the current high rates of extinction are likely to result in a significant loss of biodiversity. The evolutionary heritage of biodiversity is frequently quantified by a measure called phylogenetic diversity (PD). We predict the loss of PD under a wide class of phylogenetic tree models, where speciation rates and extinction rates may be time-dependent, and assuming independent random species extinctions at the present. We study the loss of PD when K contemporary species are selected uniformly at random from the N extant species as the surviving species, while the remaining N-K become extinct (N and K being random variables). We consider two models of species sampling, the so-called field of bullets model, where each species independently survives the extinction event at the present with probability p, and a model for which the number of surviving species is fixed. We provide explicit formulae for the expected remaining PD in both models, conditional on N=n, conditional on K=k, or conditional on both events. When N=n is fixed, we show the convergence to an explicit deterministic limit of the ratio of new to initial PD, as n→∞, both under the field of bullets model, and when K=kn is fixed and depends on n in such a way that kn/n converges to p. We also prove the convergence of this ratio as T→∞ in the supercritical, time-homogeneous case, where N simultaneously goes to ∞, thereby strengthening previous results of Mooers et al. (2012). © 2013 The Authors. Published by Elsevier Ltd. All rights reserved.

  19. Modelling the long-term impact of surface warming on Greenland ice sheet mass loss

    Science.gov (United States)

    Yang, Shuting; Anker Pedersen, Rasmus; Madsen, Marianne S.; Svendsen, Synne H.; Langen, Peter L.

    2017-04-01

    Projections of future sea level changes require understanding of the response of the Greenland ice sheet to future climate change. Numerous feedbacks between the ice sheet and the climate system mean that comprehensive model setups are required to simulate the concurrent ice sheet and climate changes. Here, the ice sheet response to a warming climate has been studied using a model setup consisting of an earth system model (EC-Earth) interactively coupled to an ice sheet model (PISM). The coupled system has been employed for a 1400-year simulation forced by historical radiative forcing from 1850 onward continued along an extended RCP8.5 scenario to beyond year 3200. The simulation reveals that the rate of mass loss from the Greenland ice sheet increases substantially after 2100. The mass loss hereafter continues at a steady rate, even as the warming rate gradually levels off. As the coupled setup does not include the direct impact of oceanic forcing, the mass loss is due to the combination of a negative surface mass balance and a dynamic response to the surface warming. Increased melt exceeds regional precipitation increases in the surface mass balance, while the surface warming increases the enthalpy (per unit volume) of the ice sheet potentially impacting the rheology and thereby the ice flow. The relative roles of the surface mass balance changes and the dynamic response of the ice flow are further investigated using additional ice sheet model sensitivity experiments, where the ice sheet is forced by the time-varying surface mass balance from the coupled model. We aim to quantify the impact of the simulated surface warming on the ice flow by means of a hybrid simulation where the ice sheet is forced by the surface mass balance from the coupled setup while keeping the ice surface temperature constant. This allows for assessment of the impact of the surface mass balance change, isolated from the dynamical response to the warming surface.

  20. A biobehavioral model of weight loss associated with meditative movement practice among breast cancer survivors

    Directory of Open Access Journals (Sweden)

    Linda K Larkey

    2014-12-01

    Full Text Available Women with breast cancer often experience weight gain during and after treatment, significantly increasing risk for recurrence as well as all-cause mortality. Based on a growing body of evidence, meditative movement practices may be effective for weight management. First, we describe the effects of stress on factors associated with weight gain for breast cancer survivors. Then, a model is proposed that utilizes existing evidence to suggest how meditative movement supports behavioral, psychological, and neurohormonal changes that may explain weight loss. Application of the model suggests how a novel “mindful-body-wisdom” approach may work to help reduce weight for this at-risk group.