Lovejoy, Andrew E.
2015-01-01
A structural concept called pultruded rod stitched efficient unitized structure (PRSEUS) was developed by the Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body (HWB) aircraft configuration. While PRSEUS was an enabling technology for the pressurized HWB structure, limited investigation of PRSEUS for other aircraft structures, such as circular fuselages and wings, has been done. Therefore, a study was undertaken to investigate the potential weight savings afforded by using the PRSEUS concept for a commercial transport wing. The study applied PRSEUS to the Advanced Subsonic Technology (AST) Program composite semi-span test article, which was sized using three load cases. The initial PRSEUS design was developed by matching cross-sectional stiffnesses for each stringer/skin combination within the wing covers, then the design was modified to ensure that the PRSEUS design satisfied the design criteria. It was found that the PRSEUS wing design exhibited weight savings over the blade-stiffened composite AST Program wing of nearly 9%, and a weight savings of 49% and 29% for the lower and upper covers, respectively, compared to an equivalent metallic wing.
Structural Weight Estimation for Launch Vehicles
Cerro, Jeff; Martinovic, Zoran; Su, Philip; Eldred, Lloyd
2002-01-01
This paper describes some of the work in progress to develop automated structural weight estimation procedures within the Vehicle Analysis Branch (VAB) of the NASA Langley Research Center. One task of the VAB is to perform system studies at the conceptual and early preliminary design stages on launch vehicles and in-space transportation systems. Some examples of these studies for Earth to Orbit (ETO) systems are the Future Space Transportation System [1], Orbit On Demand Vehicle [2], Venture Star [3], and the Personnel Rescue Vehicle[4]. Structural weight calculation for launch vehicle studies can exist on several levels of fidelity. Typically historically based weight equations are used in a vehicle sizing program. Many of the studies in the vehicle analysis branch have been enhanced in terms of structural weight fraction prediction by utilizing some level of off-line structural analysis to incorporate material property, load intensity, and configuration effects which may not be captured by the historical weight equations. Modification of Mass Estimating Relationships (MER's) to assess design and technology impacts on vehicle performance are necessary to prioritize design and technology development decisions. Modern CAD/CAE software, ever increasing computational power and platform independent computer programming languages such as JAVA provide new means to create greater depth of analysis tools which can be included into the conceptual design phase of launch vehicle development. Commercial framework computing environments provide easy to program techniques which coordinate and implement the flow of data in a distributed heterogeneous computing environment. It is the intent of this paper to present a process in development at NASA LaRC for enhanced structural weight estimation using this state of the art computational power.
Weighted Decomposition Estimates for Differential Forms
Directory of Open Access Journals (Sweden)
Yong Wang
2010-01-01
Full Text Available After introducing the definition of Ar,λβ-weights, we establish the Ar(Ω-weighted decomposition estimates and Ar,λβ(Ω-weighted Caccioppoli-type estimates for A-harmonic tensors. Furthermore, by Whitney covering lemma, we obtain the global results in domain Ω⊂Rn. These results can be used to study the integrability of differential forms and to estimate the integrals for differential forms.
Estimating liver weight of adults by body weight and gender
Institute of Scientific and Technical Information of China (English)
See Ching Chan; Chi Leung Liu; Chung Mau Lo; Banny K Lam; Evelyn W Lee; Yik Wong; Sheung Tat Fan
2006-01-01
AIM: To estimate the standard liver weight for assessing adequacies of graft size in live donor liver transplantation and remnant liver in major hepatectomy for cancer.METHODS: In this study, anthropometric data of body weight and body height were tested for a correlation with liver weight in 159 live liver donors who underwent donor right hepatectomy including the middle hepatic vein. Liver weights were calculated from the right lobe graft weight obtained at the back table, divided by the proportion of the right lobe on the computed tomography.RESULTS: The subjects, all Chinese, had a mean age of 35.8 ± 10.5 years, and a female to male ratio of 118:41. The mean volume of the right lobe was 710.14 ±131.46 mL and occupied 64.55%±4.47% of the whole liver on computed tomography. Right lobe weighed 598.90±117.39 g and the estimated liver weight was 927.54 ± 168.78 g. When body weight and body height were subjected to multiple stepwise linear regression analysis, body height was found to be insignificant. Females of the same body weight had a slightly lower liver weight. A formula based on body weight and gender was derived: Estimated standard liver weight (g) = 218 + BW (kg) x 12.3 + genderx 51 (R2 = 0.48)(female = 0, male = 1). Based on the anthropometric data of these 159 subjects, liver weights were calculated using previously published formulae derived from studies on Caucasian, Japanese, Korean, and Chinese.All formulae overestimated liver weights compared to this formula. The Japanese formula overestimated the estimated standard liver weight (ESLW) for adults less than 60 kg.CONCLUSION: A formula applicable to Chinese males and females is available. A formula for individual races appears necessary.
Weighted BMO Estimates for Toeplitz Operators on Weighted Lebesgue Spaces
Directory of Open Access Journals (Sweden)
Yan Lin
2015-01-01
Full Text Available The authors establish the weighted BMO estimates for a class of Toeplitz operators related to strongly singular Calderón-Zygmund operators on weighted Lebesgue spaces. Moreover, the corresponding result for the Toeplitz operators related to classical Calderón-Zygmund operators can be deduced.
Dimension reduction based on weighted variance estimate
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
In this paper, we propose a new estimate for dimension reduction, called the weighted variance estimate (WVE), which includes Sliced Average Variance Estimate (SAVE) as a special case. Bootstrap method is used to select the best estimate from the WVE and to estimate the structure dimension. And this selected best estimate usually performs better than the existing methods such as Sliced Inverse Regression (SIR), SAVE, etc. Many methods such as SIR, SAVE, etc. usually put the same weight on each observation to estimate central subspace (CS). By introducing a weight function, WVE puts different weights on different observations according to distance of observations from CS. The weight function makes WVE have very good performance in general and complicated situations, for example, the distribution of regressor deviating severely from elliptical distribution which is the base of many methods, such as SIR, etc. And compared with many existing methods, WVE is insensitive to the distribution of the regressor. The consistency of the WVE is established. Simulations to compare the performances of WVE with other existing methods confirm the advantage of WVE.
Dimension reduction based on weighted variance estimate
Institute of Scientific and Technical Information of China (English)
ZHAO JunLong; XU XingZhong
2009-01-01
In this paper,we propose a new estimate for dimension reduction,called the weighted variance estimate (WVE),which includes Sliced Average Variance Estimate (SAVE) as a special case.Bootstrap method is used to select the best estimate from the WVE and to estimate the structure dimension.And this selected best estimate usually performs better than the existing methods such as Sliced Inverse Regression (SIR),SAVE,etc.Many methods such as SIR,SAVE,etc.usually put the same weight on each observation to estimate central subspace (CS).By introducing a weight function,WVE puts different weights on different observations according to distance of observations from CS.The weight function makes WVE have very good performance in general and complicated situations,for example,the distribution of regressor deviating severely from elliptical distribution which is the base of many methods,such as SIR,etc.And compared with many existing methods,WVE is insensitive to the distribution of the regressor.The consistency of the WVE is established.Simulations to compare the performances of WVE with other existing methods confirm the advantage of WVE.
Generalized Jackknife Estimators of Weighted Average Derivatives
DEFF Research Database (Denmark)
Cattaneo, Matias D.; Crump, Richard K.; Jansson, Michael
With the aim of improving the quality of asymptotic distributional approximations for nonlinear functionals of nonparametric estimators, this paper revisits the large-sample properties of an important member of that class, namely a kernel-based weighted average derivative estimator. Asymptotic li...
Estimation of Weighting Potential for a TPC
Mukhopadhyay, S; Veenhof, R
2007-01-01
In this work, we have computed the three dimensional weighting potential, field and pad response function (PRF) of typical time projection chambers (TPC) using a recently formulated and developed boundary element method solver, namely, the nearly exact BEM solver. A realistic geometry of the device is found to have significant influence on the estimation of signal generation.
Convex weighting criteria for speaking rate estimation
Jiao, Yishan; Berisha, Visar; Tu, Ming; Liss, Julie
2015-01-01
Speaking rate estimation directly from the speech waveform is a long-standing problem in speech signal processing. In this paper, we pose the speaking rate estimation problem as that of estimating a temporal density function whose integral over a given interval yields the speaking rate within that interval. In contrast to many existing methods, we avoid the more difficult task of detecting individual phonemes within the speech signal and we avoid heuristics such as thresholding the temporal envelope to estimate the number of vowels. Rather, the proposed method aims to learn an optimal weighting function that can be directly applied to time-frequency features in a speech signal to yield a temporal density function. We propose two convex cost functions for learning the weighting functions and an adaptation strategy to customize the approach to a particular speaker using minimal training. The algorithms are evaluated on the TIMIT corpus, on a dysarthric speech corpus, and on the ICSI Switchboard spontaneous speech corpus. Results show that the proposed methods outperform three competing methods on both healthy and dysarthric speech. In addition, for spontaneous speech rate estimation, the result show a high correlation between the estimated speaking rate and ground truth values. PMID:26167516
Estimation and variable selection with exponential weights
Arias-Castro, Ery; Lounici, Karim
2014-01-01
In the context of a linear model with a sparse coefficient vector, exponential weights methods have been shown to be achieve oracle inequalities for denoising/prediction. We show that such methods also succeed at variable selection and estimation under the near minimum condition on the design matrix, instead of much stronger assumptions required by other methods such as the Lasso or the Dantzig Selector. The same analysis yields consistency results for Bayesian methods and BIC-type variable s...
A method to estimate weight and dimensions of large and small gas turbine engines
Onat, E.; Klees, G. W.
1979-01-01
A computerized method was developed to estimate weight and envelope dimensions of large and small gas turbine engines within + or - 5% to 10%. The method is based on correlations of component weight and design features of 29 data base engines. Rotating components were estimated by a preliminary design procedure which is sensitive to blade geometry, operating conditions, material properties, shaft speed, hub tip ratio, etc. The development and justification of the method selected, and the various methods of analysis are discussed.
Estimating topological properties of weighted networks from limited information
Gabrielli, Andrea; Cimini, Giulio; Garlaschelli, Diego; Squartini, Angelo
A typical problem met when studying complex systems is the limited information available on their topology, which hinders our understanding of their structural and dynamical properties. A paramount example is provided by financial networks, whose data are privacy protected. Yet, the estimation of systemic risk strongly depends on the detailed structure of the interbank network. The resulting challenge is that of using aggregate information to statistically reconstruct a network and correctly predict its higher-order properties. Standard approaches either generate unrealistically dense networks, or fail to reproduce the observed topology by assigning homogeneous link weights. Here we develop a reconstruction method, based on statistical mechanics concepts, that exploits the empirical link density in a highly non-trivial way. Technically, our approach consists in the preliminary estimation of node degrees from empirical node strengths and link density, followed by a maximum-entropy inference based on a combination of empirical strengths and estimated degrees. Our method is successfully tested on the international trade network and the interbank money market, and represents a valuable tool for gaining insights on privacy-protected or partially accessible systems. Acknoweledgement to ``Growthcom'' ICT - EC project (Grant No: 611272) and ``Crisislab'' Italian Project.
Weighted Estimates for Toeplitz Operators Related to Pseudodifferential Operators
Directory of Open Access Journals (Sweden)
Yan Lin
2016-01-01
Full Text Available The authors establish the weighted Lp estimates for a class of pseudodifferential operators for both cases 1
weight class is bigger than the classical Muckenhoupt’s weight class. Moreover, the weighted estimates for the Toeplitz operators related to pseudodifferential operators are also obtained. As their special cases, the corresponding results for the commutators of pseudodifferential operators can be deduced.
Gaining effciency via weighted estimators for multivariate failure time data
Institute of Scientific and Technical Information of China (English)
2009-01-01
Multivariate failure time data arise frequently in survival analysis.A commonly used tech-nique is the working independence estimator for marginal hazard models.Two natural questions are how to improve the effciency of the working independence estimator and how to identify the situations under which such an estimator has high statistical effciency.In this paper,three weighted estimators are proposed based on three different optimal criteria in terms of the asymptotic covariance of weighted estimators.Simplifiedclose-form solutions are found,which always outperform the working indepen-dence estimator.We also prove that the working independence estimator has high statistical effciency,when asymptotic covariance of derivatives of partial log-likelihood functions is nearly exchangeable or diagonal.Simulations are conducted to compare the performance of the weighted estimator and work-ing independence estimator.A data set from Busselton population health surveys is analyzed using the proposed estimators.
Preliminary evaluation of vector flow and spectral velocity estimation
DEFF Research Database (Denmark)
Pedersen, Mads Møller; Pihl, Michael Johannes; Haugaard, Per
Spectral estimation is considered as the golden standard in ultrasound velocity estimation. For spectral velocity estimation the blood flow angle is set by the ultrasound operator. Vector flow provides temporal and spatial estimates of the blood flow angle and velocity. A comparison of vector flow...... agrees with the spectral flow angle. The vector velocity estimates agrees with the spectral estimates at PS and ED. From preliminary data it is concluded that vector flow angle estimation can replace the operator-dependent angle correction used for spectral velocity estimation....... estimation and spectral estimates is presented. The variation of the blood flow angle and the effect on the velocity estimate is investigated. The right common carotid arteries of three healthy volunteers were scanned. Real-time spectral and vector flow data were obtained simultaneously from one range gate...
Estimating a weighted average of stratum-specific parameters.
Brumback, Babette A; Winner, Larry H; Casella, George; Ghosh, Malay; Hall, Allyson; Zhang, Jianyi; Chorba, Lorna; Duncan, Paul
2008-10-30
This article investigates estimators of a weighted average of stratum-specific univariate parameters and compares them in terms of a design-based estimate of mean-squared error (MSE). The research is motivated by a stratified survey sample of Florida Medicaid beneficiaries, in which the parameters are population stratum means and the weights are known and determined by the population sampling frame. Assuming heterogeneous parameters, it is common to estimate the weighted average with the weighted sum of sample stratum means; under homogeneity, one ignores the known weights in favor of precision weighting. Adaptive estimators arise from random effects models for the parameters. We propose adaptive estimators motivated from these random effects models, but we compare their design-based performance. We further propose selecting the tuning parameter to minimize a design-based estimate of mean-squared error. This differs from the model-based approach of selecting the tuning parameter to accurately represent the heterogeneity of stratum means. Our design-based approach effectively downweights strata with small weights in the assessment of homogeneity, which can lead to a smaller MSE. We compare the standard random effects model with identically distributed parameters to a novel alternative, which models the variances of the parameters as inversely proportional to the known weights. We also present theoretical and computational details for estimators based on a general class of random effects models. The methods are applied to estimate average satisfaction with health plan and care among Florida beneficiaries just prior to Medicaid reform.
Weight Estimation of Electronic Power Conversion Systems
Wen, Bo
2011-01-01
Electronic power conversion systems with large number of power converters have a variety of applications, such as data center, electric vehicles and future smart â nanogridâ in residential home. Those systems could have very different architectures. For example, one system could be based on ac, dc or hybrid power distribution bus, and the bus voltage could be different. Also those systems have great need to develop low-cost architectures which reduce weight, increase efficiency and improve...
Using the Mercy Method for Weight Estimation in Indian Children
Directory of Open Access Journals (Sweden)
Gitanjali Batmanabane MD, PhD
2015-01-01
Full Text Available This study was designed to compare the performance of a new weight estimation strategy (Mercy Method with 12 existing weight estimation methods (APLS, Best Guess, Broselow, Leffler, Luscombe-Owens, Nelson, Shann, Theron, Traub-Johnson, Traub-Kichen in children from India. Otherwise healthy children, 2 months to 16 years, were enrolled and weight, height, humeral length (HL, and mid-upper arm circumference (MUAC were obtained by trained raters. Weight estimation was performed as described for each method. Predicted weights were regressed against actual weights and the slope, intercept, and Pearson correlation coefficient estimated. Agreement between estimated weight and actual weight was determined using Bland–Altman plots with log-transformation. Predictive performance of each method was assessed using mean error (ME, mean percentage error (MPE, and root mean square error (RMSE. Three hundred seventy-five children (7.5 ± 4.3 years, 22.1 ± 12.3 kg, 116.2 ± 26.3 cm participated in this study. The Mercy Method (MM offered the best correlation between actual and estimated weight when compared with the other methods (r2 = .967 vs .517-.844. The MM also demonstrated the lowest ME, MPE, and RMSE. Finally, the MM estimated weight within 20% of actual for nearly all children (96% as opposed to the other methods for which these values ranged from 14% to 63%. The MM performed extremely well in Indian children with performance characteristics comparable to those observed for US children in whom the method was developed. It appears that the MM can be used in Indian children without modification, extending the utility of this weight estimation strategy beyond Western populations.
Sharp weighted estimates for multilinear commutators
Pérez Moreno, Carlos; Trujillo González, Rodrigo Francisco
2002-01-01
Multilinear commutators with vector symbol Formula=(b1,…,bm) defined by Formula are considered, where K is a Calderón–Zygmund kernel. The following a priori estimates are proved for w ∈ A∞. For 0 < p < ∞, there exists a constant C such that Formula and Formula where Formula Formula and ML(log L)α is an Orlicz type maximal operator. This extends, with a different approach, classical results by Coifman. As a corollary, it is deduced that the operators For...
Factors Affecting Estimated Fetal Weight Measured by Ultrasound
Directory of Open Access Journals (Sweden)
Hasan Energin
2016-06-01
Full Text Available Objective: In this study, we aimed to evaluate the factors that affect the accuracy of estimated fetal weight in ultrasound. Methods: This study was conducted in 3rd degree hospital antenatal outpatient clinic and perinatology inpatient clinic between June 2011 and January 2012. The data were obtained from 165 pregnant women. Inclusion criteria were; no additional diseases, giving birth within 48 hours after ultrasound. The same physician executed all ultrasound process. Age, height, weight, obstetric history and obstetric follow –up findings were recorded. Results: Fetal gender, fetal presentation, presence of meconium in amniotic fluid, maternal parity, did not significantly affect the accuracy of fetal weight estimation by ultrasound. The mean difference between estimated fetal weight and birth weight was 104.48±84 gr in nullipars and 94.2±81 gr in multipars (p=0.44; mean difference was 98.22±79 gr in male babies and 98.15±86 gr in female babies (p=0.99. Mean difference between estimated fetal weight and birth weight was 96.92±81 gr in babies with cephalic presentation and 110.9±90 gr in babies with breech presentation (p=0.53; this difference was 95.36±79 gr in babies with amniotic fluid with meconium and 98.82± 83 gr in babies with amniotic fluid without meconium (p=0.83. Conclusion: Fetal weight is estimation is one of key points in the obstetrician’s intrapartum managament. And it is important to make fetal weight estimation accurately. In our study, consistent with literature, we observed that fetal gender; meconium presence in amniotic fluid, fetal presentation, maternal parity does not significantly effect the accuracy of fetal weight estimation by ultrasound.
Fetal weight estimation by ultrasonic measurement of abdominal circumference.
Kearney, K; Vigneron, N; Frischman, P; Johnson, J W
1978-02-01
The purpose of this study was to compare ultrasonic measurements of fetal abdominal circumference to ultrasonic measurements of fetal biparietal diameter, as a means of estimating fetal body weight. Of 58 fetuses who had abdominal circumferences measured, 48 (82%) of the predicted weights were within 15% of the actual birth weights. Forty-four of the same 58 fetuses had satisfactory biparietal diameter measurements, but only 21 (48%) of the predicted weights were within 15% of the actual birthweights. Ultrasonic measurement of abdominal circumference appears to be a more reliable index of fetal body weight than other currently available techniques.
Weighted weak type estimates for commutators of the Marcinkiewicz integrals
Institute of Scientific and Technical Information of China (English)
DING; Yong; LU; Shanzhen; ZHANG; Pu
2004-01-01
In this paper the authors give the weighted weak LlogL type estimates for a class of the higher order commutator generated by the Marcinkiewicz integral and a BMO function. In addition, the weak type norm inequalities for the Marcinkiewicz integral and its commutators with different weight functions are also discussed.
Galeano, Javier; Iriondo, Jose M
2008-01-01
We have developed a graphical user interface (GUI) running in Matlab, called Weighted-Interaction Nestedness Estimator, WINE (Fig. 1). WINE is a Matlab application developed to perform the calculation of the new weighted nestedness estimator. This program allows the user to: open a data file, select the range of data to be analysed, and calculate the results, obtaining two graphics and three indices. The indices shown in the graphical interface are: a) weighted nestedness of the frequency matrix, b) average weighted nestedness of 100 random matrices of similar characteristics, and c) the new weighted- interaction nestedness estimator, which compares the two previous results.
Estimation of fruit weight by cane traits for various raspberries ...
African Journals Online (AJOL)
STORAGESEVER
2008-09-03
Sep 3, 2008 ... found higher (better fit) than those of Nuburg and Tulameen cultivars. It was concluded that the ... Key words: Raspberry, cane traits, fruit weight estimation, multiple regression analysis. .... Regression coefficients can be estimated by Ordinary Least Square (OLS) ... Determination coefficient (R2). Number of ...
Weighted measurement fusion Kalman estimator for multisensor descriptor system
Dou, Yinfeng; Ran, Chenjian; Gao, Yuan
2016-08-01
For the multisensor linear stochastic descriptor system with correlated measurement noises, the fused measurement can be obtained based on the weighted least square (WLS) method, and the reduced-order state components are obtained applying singular value decomposition method. Then, the multisensor descriptor system is transformed to a fused reduced-order non-descriptor system with correlated noise. And the weighted measurement fusion (WMF) Kalman estimator of this reduced-order subsystem is presented. According to the relationship of the presented non-descriptor system and the original descriptor system, the WMF Kalman estimator and its estimation error variance matrix of the original multisensor descriptor system are presented. The presented WMF Kalman estimator has global optimality, and can avoid computing these cross-variances of the local Kalman estimator, compared with the state fusion method. A simulation example about three-sensors stochastic dynamic input and output systems in economy verifies the effectiveness.
DOA Estimation with Local-Peak-Weighted CSP
Directory of Open Access Journals (Sweden)
Ichikawa Osamu
2010-01-01
Full Text Available This paper proposes a novel weighting algorithm for Cross-power Spectrum Phase (CSP analysis to improve the accuracy of direction of arrival (DOA estimation for beamforming in a noisy environment. Our sound source is a human speaker and the noise is broadband noise in an automobile. The harmonic structures in the human speech spectrum can be used for weighting the CSP analysis, because harmonic bins must contain more speech power than the others and thus give us more reliable information. However, most conventional methods leveraging harmonic structures require pitch estimation with voiced-unvoiced classification, which is not sufficiently accurate in noisy environments. In our new approach, the observed power spectrum is directly converted into weights for the CSP analysis by retaining only the local peaks considered to be harmonic structures. Our experiment showed the proposed approach significantly reduced the errors in localization, and it showed further improvements when used with other weighting algorithms.
Preliminary Cost Estimates of Pollution Control Technologies for Geothermal Developments
Energy Technology Data Exchange (ETDEWEB)
Sung, R.; Houser, G.; Richard, G.; Cotter, J.; Weller, P.; Pulaski, E.
1979-10-01
This is the first report from the EPA estimating the cost of technology for mitigating pollution that might arise from geothermal power systems. The Environmental Protection Agency (EPA) has taken an initial step towards the establishment of regulatory standards for the geothermal industry by preparing a document entitled Pollution Control Guidance for Geothermal Energy Development. This report supports that document by providing pollution control cost information. The objective of this report is to provide preliminary cost estimates for air and water pollution treatment and disposal technologies applicable for geothermal energy conversion systems. Cost estimates include both annualized capital investment and operation and maintenance (O&M) costs for various levels of environmental requirements. [DJE-2005
Weight loss and P wave dispersion: a preliminary study.
Falchi, Anna Giulia; Grecchi, Ilaria; Muggia, Chiara; Tinelli, Carmine
2014-01-01
The aim of this study is to investigate if therapeutic weight loss reduces P wave dispersion. 20 obese patients (10 males and 10 females), part of a randomized clinical trial, were examined over a 6 month period. They were treated with a diet, aiming at 5% weight loss at the 6th month. After physical examination, they underwent laboratory tests, bioelectrical impedance analysis and a electrocardiogram (ECG). ECGs were transferred to a personal computer via a scanner and then magnified 400 times. We examined at baseline and at the 6th month, maximum and minimum P-wave duration, P-wave dispersion and heart rate. Comparing responders (patients who lost 5% of weight at t6) and not responders (who lost less than 5%), responders showed a significant reduction of P wave dispersion value (-0.38 [SD: 0.35] mm equal to -32.3 [SD: 11.3] % p=0.00001). All responders present a reduction of P wave dispersion, while for not-responders this is no longer evident. Finally, a good degree of correlation (r=0.54) between P wave dispersion difference and the decrease of weight was noticed. Females have a better response in P dispersion reduction strictly connected with their weight loss with a good correlation, (r=0.7, p=0.002), versus a moderate correlation evidenced in males (r=0.5, p=0.011). P wave duration and dispersion are significantly reduced in patients who lost more than 5% of weight and this decrease is highly related to the extent of weight loss. Copyright © 2014 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
48 CFR 52.247-8 - Estimated Weights or Quantities Not Guaranteed.
2010-10-01
... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Estimated Weights or... Provisions and Clauses 52.247-8 Estimated Weights or Quantities Not Guaranteed. As prescribed in 47.207-3(e... transportation-related services when weights or quantities are estimates: Estimated Weights or Quantities...
Pera, R. J.; Onat, E.; Klees, G. W.; Tjonneland, E.
1977-01-01
Weight and envelope dimensions of aircraft gas turbine engines are estimated within plus or minus 5% to 10% using a computer method based on correlations of component weight and design features of 29 data base engines. Rotating components are estimated by a preliminary design procedure where blade geometry, operating conditions, material properties, shaft speed, hub-tip ratio, etc., are the primary independent variables used. The development and justification of the method selected, the various methods of analysis, the use of the program, and a description of the input/output data are discussed.
Institute of Scientific and Technical Information of China (English)
Juan ZHAO; Yunmin ZHU
2009-01-01
The optimally weighted least squares estimate and the linear minimum variance estimate are two of the most popular estimation methods for a linear model. In this paper, the authors make a comprehensive discussion about the relationship between the two estimates. Firstly, the authors consider the classical linear model in which the coefficient matrix of the linear model is deterministic,and the necessary and sufficient condition for equivalence of the two estimates is derived. Moreover,under certain conditions on variance matrix invertibility, the two estimates can be identical provided that they use the same a priori information of the parameter being estimated. Secondly, the authors consider the linear model with random coefficient matrix which is called the extended linear model;under certain conditions on variance matrix invertibility, it is proved that the former outperforms the latter when using the same a priori information of the parameter.
Estimated live weight of growing Pêga breed donkeys
Directory of Open Access Journals (Sweden)
Camilla Garcia Moreira
2017-09-01
Full Text Available ABSTRACT: The equations available in the literature to estimate the body weight (BW of Pêga breed donkeys were evaluated using 25 animals aged 0-6 months and it was proposed an equation for BW prediction. For the measurement of the thoracic perimeter (TP and for weighing the animals using the weighing tape, the animals were positioned in a forced station on a steep slope. An electronic scale was used for the determination of the BW. Accuracy of linear and nonlinear equations described in the literature was tested for BW prediction based on the animals’ TP, followed by the comparison of these equations with the equation developed in the present study for BW prediction of Pêga breed donkeys. A difference was noted (P<0.001 between the weights obtained on the electronic scale and the weighing tape. Linear and nonlinear equations available in the literature did not present favorable results with the data of the present study. The equation developed for the estimation of donkeys’ BW allowed the development of a weighing tape exclusive for young animals. Further evaluations are required for other Pêga donkey populations to confirm the efficacy of the proposed equation.
Preliminary Test Estimators and Phi-divergence Measures in Pooling Binomial Data
Directory of Open Access Journals (Sweden)
N. Martin
2012-07-01
Full Text Available Two independent random samples are drawn from two Binomial populations with parameters theta1 and theta2 respectively. Ahmed (1991 considered a preliminary test estimator based on maximum likelihood estimator for estimating theta1 when it is suspected that theta1=theta2. In this paper we combine minimum phi-divergence estimators as well as phi-divergence test statistics in order to define a preliminary phi-divergence test estimators. These new estimators are compared with the classical estimator as well as the pooled estimator.
Weighted-noise threshold based channel estimation for OFDM systems
Indian Academy of Sciences (India)
Pallaviram Sure; Chandra Mohan Bhuma
2015-10-01
Orthogonal frequency division multiplexing (OFDM) technology is the key to evolving telecommunication standards including 3GPP-LTE Advanced and WiMAX. Reliability of any OFDM system increases with improvedmean square error performance (MSE) of its channel estimator (CE). Particularly, a least squares (LS) based CE incorporating a time-domain denoising threshold, enables better MSE performance, while avoiding the need for a-priori knowledge of channel statistics (KCS). Existing optimal time-domain thresholds exhibit suboptimal behavior for completely unavailable KCS environments. This is because they involve consistent estimation of one or more KCS parameters, and corresponding estimation errors introduce severe degradation in MSE performance of the CE. To overcome the MSE degradation, this paper proposes a weighted-noise threshold, by introducing a modified hypothesis-testing-problem (HTP) interpretation. Derivation of resulting analytical MSE expression is also provided. Results of OFDM system simulations carried out in rayleigh faded ITU-TU6 and WiMAX-SUI4 channel environments with U-shaped power spectral densities, are presented. The performance results show that, compared to many of the existing thresholds, the proposed threshold renders better MSE performance to the CE and higher reliability to the OFDM system in terms of better bit error rate (BER) performance.
Reference Models for Structural Technology Assessment and Weight Estimation
Cerro, Jeff; Martinovic, Zoran; Eldred, Lloyd
2005-01-01
Previously the Exploration Concepts Branch of NASA Langley Research Center has developed techniques for automating the preliminary design level of launch vehicle airframe structural analysis for purposes of enhancing historical regression based mass estimating relationships. This past work was useful and greatly reduced design time, however its application area was very narrow in terms of being able to handle a large variety in structural and vehicle general arrangement alternatives. Implementation of the analysis approach presented herein also incorporates some newly developed computer programs. Loft is a program developed to create analysis meshes and simultaneously define structural element design regions. A simple component defining ASCII file is read by Loft to begin the design process. HSLoad is a Visual Basic implementation of the HyperSizer Application Programming Interface, which automates the structural element design process. Details of these two programs and their use are explained in this paper. A feature which falls naturally out of the above analysis paradigm is the concept of "reference models". The flexibility of the FEA based JAVA processing procedures and associated process control classes coupled with the general utility of Loft and HSLoad make it possible to create generic program template files for analysis of components ranging from something as simple as a stiffened flat panel, to curved panels, fuselage and cryogenic tank components, flight control surfaces, wings, through full air and space vehicle general arrangements.
Directory of Open Access Journals (Sweden)
Wararit PANICHKITKOSOLKUL
2012-09-01
Full Text Available Guttman and Tiao [1], and Chang [2] showed that the effect of outliers may cause serious bias in estimating autocorrelations, partial correlations, and autoregressive moving average parameters (cited in Chang et al. [3]. This paper presents a modified weighted symmetric estimator for a Gaussian first-order autoregressive AR(1 model with additive outliers. We apply the recursive median adjustment based on an exponentially weighted moving average (EWMA to the weighted symmetric estimator of Park and Fuller [4]. We consider the following estimators: the weighted symmetric estimator (, the recursive mean adjusted weighted symmetric estimator ( proposed by Niwitpong [5], the recursive median adjusted weighted symmetric estimator ( proposed by Panichkitkosolkul [6], and the weighted symmetric estimator using adjusted recursive median based on EWMA (. Using Monte Carlo simulations, we compare the mean square error (MSE of estimators. Simulation results have shown that the proposed estimator, , provides a MSE lower than those of , and for almost all situations.
Liu, Jingwei; Liu, Yi; Xu, Meizhi
2015-01-01
Parameter estimation method of Jelinski-Moranda (JM) model based on weighted nonlinear least squares (WNLS) is proposed. The formulae of resolving the parameter WNLS estimation (WNLSE) are derived, and the empirical weight function and heteroscedasticity problem are discussed. The effects of optimization parameter estimation selection based on maximum likelihood estimation (MLE) method, least squares estimation (LSE) method and weighted nonlinear least squares estimation (WNLSE) method are al...
Estimating total cerebral microinfarct burden from diffusion-weighted imaging
Auriel, Eitan; Westover, M. Brandon; Bianchi, Matt T; Reijmer, Yael; Martinez-Ramirez, Sergi; Ni, Jun; Van Etten, Ellis; Frosch, Matthew P; Fotiadis, Panagiotis; Schwab, Kris; Vashkevich, Anastasia; Boulouis, Grégoire; Younger, Alayna P; Johnson, Keith A; Sperling, Reisa A; Hedden, Trey; Gurol, M. Edip; Viswanathan, Anand; Greenberg, Steven M
2015-01-01
Background and Purpose Cerebral microinfarcts (CMI) are important contributors to vascular cognitive impairment. MRI diffusion-weighted imaging (DWI) hyperintensities have been suggested to represent acute CMI. We aim to describe a mathematical method for estimating total number of CMI based on the presence of incidental DWI lesions. Methods We reviewed MRI scans of subjects with cognitive decline, cognitively normal subjects and previously reported subjects with past intracerebral hemorrhage (ICH). Based on temporal and spatial characteristics of DWI lesions we estimated the annual rate of CMI needed to explain the observed rate of DWI lesion detection in each group. To confirm our estimates we performed extensive sampling for CMI in the brain of a deceased subject with past lobar ICH who found to have a DWI lesion during life. Results Clinically silent DWI lesions were present in 13 of 343 (3.8%) cognitively impaired, and 10 of 199 (5%) cognitively intact normal non-ICH patients, both lower than the incidence in the past ICH patients (23 of 178, 12.9%, p<0.0006). The predicted annual incidence of CMI ranges from 16 to 1566 for non-ICH and 50 to 5041 for ICH individuals. Histologic sampling revealed a total of 60 lesions in 32 sections. Based on previously reported methods, this density of CMI yields an estimated total brain burden MLE of 9321 CMIs (95% CI 7255–11990). Conclusions Detecting even a single DWI lesion suggests an annual incidence of hundreds of new CMI. The cumulative effects of these lesions may directly contribute to small-vessel-related vascular cognitive impairment PMID:26159796
Function estimation by feedforward sigmoidal networks with bounded weights
Energy Technology Data Exchange (ETDEWEB)
Rao, N.S.V.; Protopoescu, V. [Oak Ridge National Lab., TN (United States). Center for Engineering Systems Advanced Research; Qiao, H. [Fort Valley State Coll., GA (United States). Dept. of Mathematics and Physics
1996-05-01
The authors address the problem of PAC (probably and approximately correct) learning functions f : [0, 1]{sup d} {r_arrow} [{minus}K, K] based on iid (independently and identically distributed) sample generated according to an unknown distribution, by using feedforward sigmoidal networks. They use two basic properties of the neural networks with bounded weights, namely: (a) they form a Euclidean class, and (b) for hidden units of the form tanh ({gamma}z) they are Lipschitz functions. Either property yields sample sizes for PAC function learning under any Lipschitz cost function. The sample size based on the first property is tighter compared to the known bounds based on VC-dimension. The second estimate yields a sample size that can be conveniently adjusted by a single parameter, {gamma}, related to the hidden nodes.
Estimating topological properties of weighted networks from limited information
Cimini, Giulio; Gabrielli, Andrea; Garlaschelli, Diego
2014-01-01
A fundamental problem in studying and modeling economic and financial systems is represented by privacy issues, which put severe limitations on the amount of accessible information. Here we investigate a novel method to reconstruct the structural properties of complex weighted networks using only partial information: the total number of nodes and links, and the values of the strength for all nodes. The latter are used first as fitness to estimate the unknown node degrees through a standard configuration model; then, degrees and strengths are employed to calibrate an enhanced configuration model in order to generate ensembles of networks intended to represent the real system. The method, which is tested on the World Trade Web, while drastically reducing the amount of information needed to infer network properties, turns out to be remarkably effective$-$thus representing a valuable tool for gaining insights on privacy-protected socioeconomic networks.
Diffusion-weighted MR imaging of cystic lesions of neurocysticercosis: a preliminary study
Energy Technology Data Exchange (ETDEWEB)
Raffin, Luciana S.; Bacheschi, Luiz A.; Machado, Luis R.; Nobrega, Jose P.S.; Coelho, Christina; Leite, Claudia C. [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina. Dept. de Neurologia]. E-mail: bacheschi@henet.usp.br
2001-12-01
Neurocysticercosis is an endemic disease in some developing countries. It has pleomorfic clinical and imaging findings, which are variable from patient to patient. In this preliminary note, we studied the magnetic resonance diffusion-weighted images of sixteen patients presenting with cystic lesions of this disease diagnosed by clinical and laboratorial findings. All the lesions had hypointense signal and the similar apparent diffusion coefficient values as the cerebrospinal fluid. (author)
Faschingbauer, F; Dammer, U; Raabe, E; Schneider, M; Faschingbauer, C; Schmid, M; Mayr, A; Schild, R L; Beckmann, M W; Kehl, S
2015-07-01
To evaluate the influence of the time interval between examination and delivery on the accuracy of sonographic weight estimation (WE) in fetal macrosomia. 896 singleton pregnancies (birth weight > 4,000 g) with a total of 1,281 sonographic weight estimations were included in this retrospective cohort study. Fetuses were divided into six groups with regard to the time interval between estimation and delivery: group 1: scan-to-delivery interval: 0 days; group 2: scan-to-delivery interval: 1-3 days; group 3: scan-to-delivery interval: 4-7 days; group 4: scan-to-delivery interval: 8-14 days; group 5: scan-to-delivery interval: 15-21 days; group 6: scan-to-delivery interval: 22-42 days. The accuracy of WE was compared between five commonly used formulas using means of percentage errors (MPE), random error, medians of absolute percentage errors (MAPE), and proportions of estimates within 10 % of actual birth weight. Significant differences were found between the time interval groups with regard to MAPE and MPE values (p time interval group 1 and 2. From group 3 to 6, a continuous decrease was observed. The lowest MAPE was found with the Merz formula in group 1 and 2. Values increased continuously from group 3 to 6. Differences between time interval group one and three did not reach statistical significance. WE in fetal macrosomia shows the best results when examinations are performed within 7 days before delivery, using the formula of Merz et al. Accuracy significantly decreases after this time period.
Estimates of Oseen kernels in weighted $L^{p}$ spaces
KRAČMAR, Stanislav; Novotný, Antonín; Pokorný, Milan
2001-01-01
We study convolutions with Oseen kernels (weakly singular and singular) in both two- and three-dimensional space. We give a detailed weighted $L^{p}$ theory for $ p\\in(1;\\infty$ ] for anisotropic weights.
Magis, David; Raiche, Gilles
2012-01-01
This paper focuses on two estimators of ability with logistic item response theory models: the Bayesian modal (BM) estimator and the weighted likelihood (WL) estimator. For the BM estimator, Jeffreys' prior distribution is considered, and the corresponding estimator is referred to as the Jeffreys modal (JM) estimator. It is established that under…
Preliminary estimate of natural resource damage : Rocky Mountain Arsenal Superfund Site
US Fish and Wildlife Service, Department of the Interior — This is a preliminary estimate of natural resource damages associated with uncontrolled release of hazardous materials at the Rocky Mountain Arsenal Superfund Site...
Institute of Scientific and Technical Information of China (English)
Marta C.SOARES; Gon(c)alo I.ANDR(E); José R.PAULA
2015-01-01
Brain size and weight vary tremendously in the animal kingdom.It has been suggested that brain structural development must evolve balanced between the advantages of dealing with greater social challenges and the energetic costs of maintaining and developing larger brains.Here we ask if interspecific differences in cooperative behaviour (i.e.cleaning behaviour) are related to brain weight variations in four close-related species of Labrid fish:two are obligatory cleanerfish throughout their entire life (Labroides dimidiatus and L.bicolor),one facultative cleaner fish Labropsis australis and one last species that never engage in cleaning Labrichthys unilineatus.We first search for the link between the rate of species' cooperation and its relative brain weight,and finally,if the degree of social complexity and cooperation are reflected in the weight of its major brain substructures.Overall,no differences were found in relative brain weight (in relation to body weight) across species.Fine-scale differences were solely demonstrated for the facultative cleaner L.australis,at the brainstem level.Furthermore,data visual examination indicates that the average cerebellum and brainstem weights appear to be larger for L.dimidiatus.Because variation was solely found at specific brain areas (such as cerebellum and brainstem) and not for the whole brain weight values,it suggests that species social-ecological and cognitive demands may be directly contributing to a selective investment in relevant brain areas.This study provides first preliminary evidence that links potential differences in cognitive ability in cooperative behaviour to how these may mediate the evolution of brain structural development in non-mammal vertebrate groups [Current Zoology 61 (2):274-280,2015].
Bui, The Anh; D'Ancona, Piero; Duong, Xuan Thinh; Li, Ji; Ly, Fu Ken
2017-02-01
Let La be a Schrödinger operator with inverse square potential a | x|-2 on Rd, d ≥ 3. The main aim of this paper is to prove weighted estimates for fractional powers of La. The proof is based on weighted Hardy inequalities and weighted inequalities for square functions associated to La. As an application, we obtain smoothing estimates regarding the propagator e itLa.
A weight modification sequential method for VSC-MTDC power system state estimation
Yang, Xiaonan; Zhang, Hao; Li, Qiang; Guo, Ziming; Zhao, Kun; Li, Xinpeng; Han, Feng
2017-06-01
This paper presents an effective sequential approach based on weight modification for VSC-MTDC power system state estimation, called weight modification sequential method. The proposed approach simplifies the AC/DC system state estimation algorithm through modifying the weight of state quantity to keep the matrix dimension constant. The weight modification sequential method can also make the VSC-MTDC system state estimation calculation results more ccurate and increase the speed of calculation. The effectiveness of the proposed weight modification sequential method is demonstrated and validated in modified IEEE 14 bus system.
Effectiveness of Vehicle Weight Estimation from Bridge Weigh-in-Motion
Directory of Open Access Journals (Sweden)
Teerachai Deesomsuk
2009-01-01
Full Text Available The effectiveness of vehicle weight estimations from bridge weigh-in-motion system is studied. The measured bending moments of the instrumented bridge under a passage of vehicle are numerically simulated and are used as the input for the vehicle weight estimations. Two weight estimation methods assuming constant magnitudes and time-varying magnitudes of vehicle axle loads are investigated. The appropriate number of bridge elements and sampling frequency are considered. The effectiveness in term of the estimation accuracy is evaluated and compared under various parameters of vehicle-bridge system. The effects of vehicle speed, vehicle configuration, vehicle weight and bridge surface roughness on the accuracy of the estimated vehicle weights are intensively investigated. Based on the obtained results, vehicle speed, surface roughness level and measurement error seem to have stronger effects on the weight estimation accuracy than other parameters. In general, both methods can provide quite accurate weight estimation of the vehicle. Comparing between them, although the weight estimation method assuming constant magnitudes of axle loads is faster, the method assuming time-varying magnitudes of axle loads can provide axle load histories and exhibits more accurate weight estimations of the vehicle for almost of the considered cases.
Hanford, K J; Van Vleck, L D; Snowder, G D
2003-03-01
Genetic parameters from both single-trait and bivariate analyses for prolificacy, weight, and wool traits were estimated using REML with animal models for Targhee sheep from data collected from 1950 to 1998 at the U.S. Sheep Experiment Station, Dubois, ID. Breeding values from both single-trait and seven-trait analyses calculated with the parameters estimated from the single-trait and bivariate analyses were compared across years of birth with respect to genetic trends. The numbers of observations were 38,625 for litter size at birth and litter size at weaning, 33,994 for birth weight, 32,715 for weaning weight, 36,807 for fleece weight and fleece grade, and 3,341 for staple length. Direct heritability estimates from single-trait analyses were 0.10 for litter size at birth, 0.07 for litter size at weaning, 0.25 for birth weight, 0.22 for weaning weight, 0.54 for fleece weight, 0.41 for fleece grade, and 0.65 for staple length. Estimate of direct genetic correlation between litter size at birth and weaning was 0.77 and between birth and weaning weights was 0.52. The estimate of genetic correlation between fleece weight and staple length was positive (0.54), but was negative between fleece weight and fleece grade (-0.47) and between staple length and fleece grade (-0.69). Estimates of genetic correlations were near zero between birth weight and litter size traits and small and positive between weaning weight and litter size traits. Fleece weight was slightly and negatively correlated with both litter size traits. Fleece grade was slightly and positively correlated with both litter size traits. Estimates of correlations between staple length and litter size at birth (-0.14) and litter size at weaning (0.05) were small. Estimates of correlations between weight traits and fleece weight were positive and low to moderate. Estimates of correlations between weight traits and fleece grade were negative and small, whereas estimates between weight traits and staple length were
Hanford, K J; Van Vleck, L D; Snowder, G D
2002-12-01
Genetic parameters from both single-trait and bivariate analyses for prolificacy, weight and wool traits were estimated using REML with animal models for Columbia sheep from data collected from 1950 to 1998 at the U.S. Sheep Experiment Station (USSES), Dubois, ID. Breeding values from both single-trait and seven-trait analyses calculated using the parameters estimated from the single-trait and bivariate analyses were compared with respect to genetic trends. Number of observations were 31,401 for litter size at birth and litter size at weaning, 24,741 for birth weight, 23,903 for weaning weight, 29,572 for fleece weight and fleece grade, and 2,449 for staple length. Direct heritability estimates from single-trait analyses were 0.09 for litter size at birth, 0.06 for litter size at weaning, 0.27 for birth weight, 0.16 for weaning weight, 0.53 for fleece weight, 0.41 for fleece grade, and 0.55 for staple length. Estimate of direct genetic correlation between littersize at birth and weaning was 0.84 and between birth and weaning weights was 0.56. Estimate of genetic correlation between fleece weight and staple length was positive (0.55) but negative between fleece weight and fleece grade (-0.47) and between staple length and fleece grade (-0.70). Estimates of genetic correlations were positive but small between birth weight and litter size traits and moderate and positive between weaning weight and litter size traits. Fleece weight was lowly and negatively correlated with both litter size traits. Fleece grade was lowly and positively correlated with both litter size traits, while staple length was lowly and negatively correlated with the litter size traits. Estimates of correlations between weight traits and fleece weight were positive and low to moderate. Estimates of correlations between weight traits and fleece grade were negative and small. Estimates of correlations between staple length and birth weight (0.05) and weaning weight were small (-0.04). Estimated
A note on stereological estimation of the volume-weighted second moment of particle volume
DEFF Research Database (Denmark)
Jensen, E B; Sørensen, Flemming Brandt
1991-01-01
It is shown that for a variety of biological particle shapes, the volume-weighted second moment of particle volume can be estimated stereologically using only the areas of particle transects, which can be estimated manually by point-counting.......It is shown that for a variety of biological particle shapes, the volume-weighted second moment of particle volume can be estimated stereologically using only the areas of particle transects, which can be estimated manually by point-counting....
Estimated genetic trends for weaning weight in three Dorper lines ...
African Journals Online (AJOL)
selection criteria. F.W.C. Neser,*l K.V. ... Selection on breed standards and selection on weaning weight under ... following criteria: .... 1 2 t 1 5 6 f t 0 10111213141516171819 .... explained by the fact that up to yearlseason nine, sires with.
Improved parameter estimation for hydrological models using weighted object functions
Stein, A.; Zaadnoordijk, W.J.
1999-01-01
This paper discusses the sensitivity of calibration of hydrological model parameters to different objective functions. Several functions are defined with weights depending upon the hydrological background. These are compared with an objective function based upon kriging. Calibration is applied to pi
Comparison of Broselow tape measurements versus mother estimations of pediatric weights
Directory of Open Access Journals (Sweden)
Sherafat Akaberian
2013-06-01
Full Text Available Background Pediatric resuscitation is challenging for therapeutic group. The most physicians have limited experience in dealing with this situation. Appropriate dosing of the drugs depends on the body weight of the children that it is usually not feasible. There is need for a fast, convenient and reliable method for body weight estimation in children. The aim of this study was to assess the accuracy of Broselow tape in children of Bushehr city. Material and Methods: This cross-sectional study was conducted in the emergency department of Aliasghar hospital. Children were between 1 month and 14 years. Children with chronic disease, 334, ill children were excluded from study. Estimated weight measured based on Broselow tape and actual weight measured by digital scale, then estimated and actual weight were compared. The results were analyzed by SPSS Software Ver 18 and T-Test, Chi-Square Test. Results: findings showed that 43.2% of total subjects were female Mean of age were 43 months. 72.5% of tape body weights were within 10% error of actual body weights. 78.9% of tape body weight was within 15% error of actual body weights. There was no significant difference between boys and girls. Conclusion: Broslow tape was easy, fast and exact for body weight estimation in emergency situation .it is more exact of body weight estimation by parents or therapeutic group so it helps therapeutic group in emergency department for accounting of medication dosage and equipment sizes.
Abd. Rahni, Ashrani Aizzuddin; Arka, Israna Hossain; Chellappan, Kalaivani; Mukari, Shahizon Azura; Law, Zhe Kang; Sahathevan, Ramesh
2016-03-01
In this paper we present preliminary results of comparison of automatic segmentations of the infarct core, between that obtained from CT perfusion (based on time to peak parameter) and diffusion weighted imaging (DWI). For each patient, the two imaging volumes were automatically co-registered to a common frame of reference based on an acquired CT angiography image. The accuracy of image registration is measured by the overlap of the segmented brain from both images (CT perfusion and DWI), measured within their common field of view. Due to the limitations of the study, DWI was acquired as a follow up scan up to a week after initial CT based imaging. However, we found significant overlap of the segmented brain (Jaccard indices of approximately 0.8) and the percentage of infarcted brain tissue from the two modalities were still fairly highly correlated (correlation coefficient of approximately 0.9). The results are promising with more data needed in future for clinical inference.
Underdetermined DOA Estimation Using MVDR-Weighted LASSO
Salama, Amgad A.; Ahmad, M. Omair; Swamy, M. N. S.
2016-01-01
The direction of arrival (DOA) estimation problem is formulated in a compressive sensing (CS) framework, and an extended array aperture is presented to increase the number of degrees of freedom of the array. The ordinary least square adaptable least absolute shrinkage and selection operator (OLS A-LASSO) is applied for the first time for DOA estimation. Furthermore, a new LASSO algorithm, the minimum variance distortionless response (MVDR) A-LASSO, which solves the DOA problem in the CS framework, is presented. The proposed algorithm does not depend on the singular value decomposition nor on the orthogonality of the signal and the noise subspaces. Hence, the DOA estimation can be done without a priori knowledge of the number of sources. The proposed algorithm can estimate up to ((M2−2)/2+M−1)/2 sources using M sensors without any constraints or assumptions about the nature of the signal sources. Furthermore, the proposed algorithm exhibits performance that is superior compared to that of the classical DOA estimation methods, especially for low signal to noise ratios (SNR), spatially-closed sources and coherent scenarios. PMID:27657080
Underdetermined DOA Estimation Using MVDR-Weighted LASSO
Directory of Open Access Journals (Sweden)
Amgad A. Salama
2016-09-01
Full Text Available The direction of arrival (DOA estimation problem is formulated in a compressive sensing (CS framework, and an extended array aperture is presented to increase the number of degrees of freedom of the array. The ordinary least square adaptable least absolute shrinkage and selection operator (OLS A-LASSO is applied for the first time for DOA estimation. Furthermore, a new LASSO algorithm, the minimum variance distortionless response (MVDR A-LASSO, which solves the DOA problem in the CS framework, is presented. The proposed algorithm does not depend on the singular value decomposition nor on the orthogonality of the signal and the noise subspaces. Hence, the DOA estimation can be done without a priori knowledge of the number of sources. The proposed algorithm can estimate up to ( ( M 2 − 2 / 2 + M − 1 / 2 sources using M sensors without any constraints or assumptions about the nature of the signal sources. Furthermore, the proposed algorithm exhibits performance that is superior compared to that of the classical DOA estimation methods, especially for low signal to noise ratios (SNR, spatially-closed sources and coherent scenarios.
Preliminary results on uncertainties in rainfall interception estimation
Energy Technology Data Exchange (ETDEWEB)
Muzylo, A.; Llorens, P.; Domingo, F.; Valente, Fe.; Beven, K.; Gallart, F.
2009-07-01
This work deals with some aspects of rainfall interception estimation uncertainty in a deciduous forest. The importance of interception loss measurement error is stressed. Confidence limits of Rutter original and sparse interception model parameters obtained from regressions for leafed and leafless period are presented, as well as free throughfall coefficient variability with event weather conditions. (Author) 8 refs.
Parameters Estimation of Geographically Weighted Ordinal Logistic Regression (GWOLR) Model
Zuhdi, Shaifudin; Retno Sari Saputro, Dewi; Widyaningsih, Purnami
2017-06-01
A regression model is the representation of relationship between independent variable and dependent variable. The dependent variable has categories used in the logistic regression model to calculate odds on. The logistic regression model for dependent variable has levels in the logistics regression model is ordinal. GWOLR model is an ordinal logistic regression model influenced the geographical location of the observation site. Parameters estimation in the model needed to determine the value of a population based on sample. The purpose of this research is to parameters estimation of GWOLR model using R software. Parameter estimation uses the data amount of dengue fever patients in Semarang City. Observation units used are 144 villages in Semarang City. The results of research get GWOLR model locally for each village and to know probability of number dengue fever patient categories.
Spectral covolatility estimation from noisy observations using local weights
Bibinger, Markus
2011-01-01
We propose localized spectral estimators for the quadratic covariation and the spot covolatility of diffusion processes which are observed discretely with additive observation noise. The eligibility of this approach to lead to an appropriate estimation for time-varying volatilities stems from an asymptotic equivalence of the underlying statistical model to a white noise model with correlation and volatility processes being constant over small intervals. The asymptotic equivalence of the continuous-time and the discrete-time experiments are proved by a construction with linear interpolation in one direction and local means for the other. The new estimator outperforms earlier nonparametric approaches in the considered model. We investigate its finite sample size characteristics in simulations and draw a comparison between the various proposed methods.
Area-to-point parameter estimation with geographically weighted regression
Murakami, Daisuke; Tsutsumi, Morito
2015-07-01
The modifiable areal unit problem (MAUP) is a problem by which aggregated units of data influence the results of spatial data analysis. Standard GWR, which ignores aggregation mechanisms, cannot be considered to serve as an efficient countermeasure of MAUP. Accordingly, this study proposes a type of GWR with aggregation mechanisms, termed area-to-point (ATP) GWR herein. ATP GWR, which is closely related to geostatistical approaches, estimates the disaggregate-level local trend parameters by using aggregated variables. We examine the effectiveness of ATP GWR for mitigating MAUP through a simulation study and an empirical study. The simulation study indicates that the method proposed herein is robust to the MAUP when the spatial scales of aggregation are not too global compared with the scale of the underlying spatial variations. The empirical studies demonstrate that the method provides intuitively consistent estimates.
Directory of Open Access Journals (Sweden)
Karuna
2014-03-01
Full Text Available BACKGROUND: Accurate determination of fetal birth weight prior to delivery can have significant bearing on management decision in labor, thereby markedly improving perinatal outcome. OBJECTIVE: To assess fetal weight in term pregnancy by different clinical and ultrasonographical methods. MATERIALS AND METHODS: The study was conducted in Obstetrics and Gynecology department of Dr. D.Y. Patil Medical College, Pimpri, Pune. Two hundred (200 women were selected and studied for a period of one year based on convenience sampling from October 2011 to September 2013.The fetal weight was estimated a week prior to the delivery by both ultrasound and clinical examination. Various formulae’s for estimation of fetal weight were applied based on Ultrasound and clinical parameters. All results arising from different formulas were studied and suitable statistics was applied and compared to have clear idea regarding results. RESULTS: All results arising from different formulas were studied by Descriptive statistics and compared with Actual weight at the time of delivery (gold standard. A box plot was used to differentiate various methods used for estimation of fetal weight, It shows that Johnson, Dawn formula and weight in gms (Dare’s formula corresponds with the base line indicating that they can predict birth weight correctly and among these Johnson showed promising results, whereas formulas like Campbell, Comb’s, Hadlock and Warsof didn’t predict birth weight as accurately as the three clinical methods used, thus in our study it can be seen that clinical methods are better predictors of birth weight than ultrasonographic methods. CONCLUSIONS: In our study it was observed that Clinical methods used for estimation of fetal birth weight was found to be by far simple and reliable methods in estimation of fetal birth weight than Ultrasonographic estimation methods and thus holds importance in day to day practice especially in countries like us where still
Inkmann, J.
2005-01-01
The inverse probability weighted Generalised Empirical Likelihood (IPW-GEL) estimator is proposed for the estimation of the parameters of a vector of possibly non-linear unconditional moment functions in the presence of conditionally independent sample selection or attrition.The estimator is applied
43 CFR 11.38 - Assessment Plan-preliminary estimate of damages.
2010-10-01
... damages. 11.38 Section 11.38 Public Lands: Interior Office of the Secretary of the Interior NATURAL RESOURCE DAMAGE ASSESSMENTS Assessment Plan Phase § 11.38 Assessment Plan—preliminary estimate of damages... resources, if the authorized official intends to include compensable value in the damage claim....
Nair, Kalyani P.; Harkness, Elaine F.; Gadde, Soujanye; Lim, Yit Y.; Maxwell, Anthony J.; Moschidis, Emmanouil; Foden, Philip; Cuzick, Jack; Brentnall, Adam; Evans, D. Gareth; Howell, Anthony; Astley, Susan M.
2017-03-01
Personalised breast screening requires assessment of individual risk of breast cancer, of which one contributory factor is weight. Self-reported weight has been used for this purpose, but may be unreliable. We explore the use of volume of fat in the breast, measured from digital mammograms. Volumetric breast density measurements were used to determine the volume of fat in the breasts of 40,431 women taking part in the Predicting Risk Of Cancer At Screening (PROCAS) study. Tyrer-Cuzick risk using self-reported weight was calculated for each woman. Weight was also estimated from the relationship between self-reported weight and breast fat volume in the cohort, and used to re-calculate Tyrer-Cuzick risk. Women were assigned to risk categories according to 10 year risk (below average =8%) and the original and re-calculated Tyrer-Cuzick risks were compared. Of the 716 women diagnosed with breast cancer during the study, 15 (2.1%) moved into a lower risk category, and 37 (5.2%) moved into a higher category when using weight estimated from breast fat volume. Of the 39,715 women without a cancer diagnosis, 1009 (2.5%) moved into a lower risk category, and 1721 (4.3%) into a higher risk category. The majority of changes were between below average and average risk categories (38.5% of those with a cancer diagnosis, and 34.6% of those without). No individual moved more than one risk group. Automated breast fat measures may provide a suitable alternative to self-reported weight for risk assessment in personalized screening.
A Distributed Weighted Voting Approach for Accurate Eye Center Estimation
Directory of Open Access Journals (Sweden)
Gagandeep Singh
2013-05-01
Full Text Available This paper proposes a novel approach for accurate estimation of eye center in face images. A distributed voting based approach in which every pixel votes is adopted for potential eye center candidates. The votes are distributed over a subset of pixels which lie in a direction which is opposite to gradient direction and the weightage of votes is distributed according to a novel mechanism. First, image is normalized to eliminate illumination variations and its edge map is generated using Canny edge detector. Distributed voting is applied on the edge image to generate different eye center candidates. Morphological closing and local maxima search are used to reduce the number of candidates. A classifier based on spatial and intensity information is used to choose the correct candidates for the locations of eye center. The proposed approach was tested on BioID face database and resulted in better Iris detection rate than the state-of-the-art. The proposed approach is robust against illumination variation, small pose variations, presence of eye glasses and partial occlusion of eyes.Defence Science Journal, 2013, 63(3, pp.292-297, DOI:http://dx.doi.org/10.14429/dsj.63.2763
Simple Reshaping of the Breast in Massive Weight Loss Patients: Promising Preliminary Results.
Ikander, Peder; Gad, Dorte; Gunnarsson, Gudjon Leifur; Boljanovic, Slaven; Salzberg, Andrew; Sørensen, Jens Ahm; Thomsen, Jørn Bo
2017-02-01
The challenging breast reshaping after massive weight loss (MWL) has been increasingly performed as the number of bariatric surgery procedures increase worldwide. The breasts often appear wide, lateralized, and deflated, with significant ptosis. The aim of this article is to share our initial experience using the lower pole subglandular advancement mastoplasty (LOPOSAM) technique to reshape the breasts in MWL patients and to elaborate the technical details and simplicity of the method in the attached video. We performed 30 LOPOSAM procedures in 15 MWL women aged 24 to 63 years from February to September 2015. We used a wise pattern mark-up and a superior based pedicle for the relocation of the nipple areola complex. The key step for the autoaugmentation was an inferior and central mound based parabola-shaped flap, which was placed in a subglandular pocket to reshape the breast and lift the inframammary crease. The median operation time for the LOPOSAM procedure was 81 minutes (range, 35-160 minutes) by 2 surgeons. The median weight loss was 64 kg (range, 45-103) and 22 body mass index units (range, 16-33) per patient. The median follow-up was 240 days (range, 105 Powered by Editorial Manager and ProduXion Manager from Aries Systems Corporation to 345). The surgical goal was achieved in all cases. Four complications occurred in 3 patients, 1 major, a hematoma-requiring surgery and 3 minor wound dehiscence. The self-reported patient satisfaction was high, 13 were very satisfied with the result, 1 satisfied, and 1 less satisfied. The LOPOSAM technique is quick and simple to perform, and the preliminary results are promising. However, a longer follow-up is needed to confirm this.
2005-01-01
The inverse probability weighted Generalised Empirical Likelihood (IPW-GEL) estimator is proposed for the estimation of the parameters of a vector of possibly non-linear unconditional moment functions in the presence of conditionally independent sample selection or attrition.The estimator is applied to the estimation of the firm size elasticity of product and process R&D expenditures using a panel of German manufacturing firms, which is affected by attrition and selection into R&D activities....
Habecker, Patrick; Dombrowski, Kirk; Khan, Bilal
2015-01-01
Researchers interested in studying populations that are difficult to reach through traditional survey methods can now draw on a range of methods to access these populations. Yet many of these methods are more expensive and difficult to implement than studies using conventional sampling frames and trusted sampling methods. The network scale-up method (NSUM) provides a middle ground for researchers who wish to estimate the size of a hidden population, but lack the resources to conduct a more specialized hidden population study. Through this method it is possible to generate population estimates for a wide variety of groups that are perhaps unwilling to self-identify as such (for example, users of illegal drugs or other stigmatized populations) via traditional survey tools such as telephone or mail surveys—by asking a representative sample to estimate the number of people they know who are members of such a “hidden” subpopulation. The original estimator is formulated to minimize the weight a single scaling variable can exert upon the estimates. We argue that this introduces hidden and difficult to predict biases, and instead propose a series of methodological advances on the traditional scale-up estimation procedure, including a new estimator. Additionally, we formalize the incorporation of sample weights into the network scale-up estimation process, and propose a recursive process of back estimation “trimming” to identify and remove poorly performing predictors from the estimation process. To demonstrate these suggestions we use data from a network scale-up mail survey conducted in Nebraska during 2014. We find that using the new estimator and recursive trimming process provides more accurate estimates, especially when used in conjunction with sampling weights. PMID:26630261
Directory of Open Access Journals (Sweden)
Patrick Habecker
Full Text Available Researchers interested in studying populations that are difficult to reach through traditional survey methods can now draw on a range of methods to access these populations. Yet many of these methods are more expensive and difficult to implement than studies using conventional sampling frames and trusted sampling methods. The network scale-up method (NSUM provides a middle ground for researchers who wish to estimate the size of a hidden population, but lack the resources to conduct a more specialized hidden population study. Through this method it is possible to generate population estimates for a wide variety of groups that are perhaps unwilling to self-identify as such (for example, users of illegal drugs or other stigmatized populations via traditional survey tools such as telephone or mail surveys--by asking a representative sample to estimate the number of people they know who are members of such a "hidden" subpopulation. The original estimator is formulated to minimize the weight a single scaling variable can exert upon the estimates. We argue that this introduces hidden and difficult to predict biases, and instead propose a series of methodological advances on the traditional scale-up estimation procedure, including a new estimator. Additionally, we formalize the incorporation of sample weights into the network scale-up estimation process, and propose a recursive process of back estimation "trimming" to identify and remove poorly performing predictors from the estimation process. To demonstrate these suggestions we use data from a network scale-up mail survey conducted in Nebraska during 2014. We find that using the new estimator and recursive trimming process provides more accurate estimates, especially when used in conjunction with sampling weights.
WEIGHTED ESTIMATES FOR COMMUTATORS OF POTENTIAL OPERATORS ON SPACES OF HOMOGENEOUS TYPE
Institute of Scientific and Technical Information of China (English)
Wenming Li; Xiaowu Yu; Xuefang Yan
2009-01-01
We derive some strong type and weak type weighted norm estimates which relate the commutators of potential integral operators to the corresponding maximal operators in the context of spaces of homogeneous type.
A Weighted Estimate for the Square Function on the Unit Ball in $\\C^n$
PETERMICHL, stefanie; Wick, Brett D.
2007-01-01
We show that the Luzin area integral or the square function on the unit ball of ℂn, regarded as an operator in the weighted space L2(w) has a linear bound in terms of the invariant A2 characteristic of the weight. We show a dimension-free estimate for the “area-integral” associated with the weighted L2(w) norm of the square function. We prove the equivalence of the classical and the invariant A2 classes.
Weak type estimates of intrinsic square functions on the weighted Hardy spaces
Wang, Hua
2010-01-01
In this paper, by using the atomic decomposition theory of weighted Hardy spaces, we will give some weighted weak type estimates for intrinsic square functions including the Lusin area function, Littlewood-Paley $g$-function and $g^*_\\lambda$-function on these spaces.
Weak type estimates of intrinsic square functions on the weighted Herz-type Hardy spaces
Wang, Hua
2010-01-01
In this paper, by using the atomic decomposition theory of weighted Herz-type Hardy spaces, we will obtain some weighted weak type estimates for intrinsic square functions including the Lusin area function, Littlewood-Paley $g$-function and $g^*_\\lambda$-function on these spaces.
Simon, N V; Levisky, J S; Shearer, D M; Morris, K C; Hansberry, P A
1988-06-01
We evaluated the predictiveness of sonographically estimated fetal weight as a function of the estimation of probability of having intrauterine growth retardation (IUGR) before obtaining an ultrasound scan (prior probability). The value of the estimated fetal weight resided more in its high specificity than in its sensitivity, hence in its ability to confirm that the fetus is normal. The predictiveness of the method was further enhanced when the fetal weight estimation was placed in the context of the prior probability of IUGR. In particular, the positive predictive value of the test as well as the likelihood of having a growth-retarded infant in spite of an estimated fetal weight within the normal range were considerably higher as the prior probability of IUGR increased. Since the obstetrician using all available evidence is likely to form a rather good estimate of the possibility of IUGR before ordering a scan, this improvement in the predictiveness of estimated fetal weight through a Bayesian approach can be advantageously applied to ultrasound analysis and can effectively support clinical decision making.
Sharp weak type estimates for weights in the class $A_{p_1, p_2}$
Reznikov, Alexander
2011-01-01
We get sharp estimates for the distribution function of nonnegative weights, which satisfy so called $A_{p_1, p_2}$ condition. For particular choices of parameters $p_1$, $p_2$ this condition becomes an $A_p$-condition or Reverse H\\"{o}lder condition. We also get maximizers for these sharp estimates. We use the Bellman technique and try to carefully present and motivate our tactics. As an illustration of how these results can be used, we deduce the following result: if a weight $w$ is in $A_2$ then it self-improves to a weight, which satisfies a Reverse H\\"{o}lder condition.
New HB-weighted time delay estimation algorithm under impulsive noise environment*
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
The traditional HB-weighted time-delay estimation (TDE) method degenerates under the impulsive noise environment. Two new time-delay estimation methods are proposed based on fractional lower order statistics (FLOS) according to the impulsive characteristics of fractional lower order α-stable noises. Theoretic analysis and computer simulations indicate that the proposed covariation based HB weighted (COV-HB) algorithm can suppress impulsive noises in one received signal for 1 ≤α≤ 2, whereas the other proposed fractional lower order covariance-based HB weighted (FLOC-HB) algorithm has robust performance under arbitrary impulsive noise conditions for the whole range of 0 < α≤ 2.
Burgos, Jorge; Melchor, Juan Carlos; Cobos, Patricia; Centeno, Marimar; Pijoan, Jose Ignacio; Fernandez-Llebrez, Luis; Martinez-Astorquiza, Txanton
2009-01-01
OBJECTIVE. To determine whether fetal weight estimated by ultrasound on the day the external cephalic version (ECV) is related to the procedure's success rate. DESIGN. Retrospective cohort study. Setting. University hospital. POPULATION OR SAMPLE. Two hundred women with a singleton pregnancy undergoing an ECV attempt between March 2002 and March 2006. METHOD. Projected birthweight at delivery was calculated. Logistic regression analysis, by grams and by weight intervals, and multiple correspondence analysis were performed to determine whether or not the weight was related to the procedure's success. Specific statistical analysis was undertaken to minimize measurement bias in fetal weight estimation. MAIN OUTCOME MEASURE. Success of ECV in relation to estimated fetal weight. RESULTS. Measurement bias was ruled out because no statistically significant differences were identified with the Student's t-test (p>0.05), Bland-Altman's agreement analysis, and the interclass correlation coefficient analysis (ICC = 0.829; CI95% 0.772-0.871; psuccess was detected, while multiple correspondence analysis suggested that variations in fetal weight are weakly related to the procedure's success or failure. No relation was identified between ECV and birthweight (p = 0.38) when the delivery took place in the same week as the version. CONCLUSIONS. Estimated fetal weight before ECV seems not to be related to the outcome of ECV.
Bowen, L; Zyambo, M; Snell, D; Kinnear, J; Bould, M D
2016-12-27
Limited resources and access to healthcare in sub-Saharan Africa are associated with high rates of malnourished children, although many countries globally are demonstrating increasing childhood obesity. This study evaluated how well current age- or height-based formulae estimate the weight of children undergoing surgery in Zambia. All children under 14 years of age presenting for elective surgery at the University Teaching Hospital, Lusaka, had both height and weight measured. Their actual weight was compared against estimated weight from various formulae. The Broselow tape outperformed all the age-based formulae, demonstrating the lowest median percentage error of -5.8%, with 46.0% of estimates falling within 10% of the actual measured weight (p < 0.001). Of the 1111 children who were eligible for World Health Organization growth standard appraisal, 88 (8%) met the weight criteria for severe acute malnutrition. Our results are consistent with other studies in finding that the Broselow tape is the best estimator of weight in a lower middle-income country, followed by the original Advanced Paediatric Life Support formula if the Broselow tape is unavailable.
Weighted Maximum-a-Posteriori Estimation in Tests Composed of Dichotomous and Polytomous Items
Sun, Shan-Shan; Tao, Jian; Chang, Hua-Hua; Shi, Ning-Zhong
2012-01-01
For mixed-type tests composed of dichotomous and polytomous items, polytomous items often yield more information than dichotomous items. To reflect the difference between the two types of items and to improve the precision of ability estimation, an adaptive weighted maximum-a-posteriori (WMAP) estimation is proposed. To evaluate the performance of…
Univariate and Default Standard Unit Biases in Estimation of Body Weight and Caloric Content
Geier, Andrew B.; Rozin, Paul
2009-01-01
College students estimated the weight of adult women from either photographs or a live presentation by a set of models and estimated the calories in 1 of 2 actual meals. The 2 meals had the same items, but 1 had larger portion sizes than the other. The results suggest: (a) Judgments are biased toward transforming the example in question to the…
Weighted Maximum-a-Posteriori Estimation in Tests Composed of Dichotomous and Polytomous Items
Sun, Shan-Shan; Tao, Jian; Chang, Hua-Hua; Shi, Ning-Zhong
2012-01-01
For mixed-type tests composed of dichotomous and polytomous items, polytomous items often yield more information than dichotomous items. To reflect the difference between the two types of items and to improve the precision of ability estimation, an adaptive weighted maximum-a-posteriori (WMAP) estimation is proposed. To evaluate the performance of…
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
The consistency measurement and weight estimation approach of the hybrid uncertain comparison matrix in the analytic hierarchy process (AHP) are studied. First, the decision-making satisfaction membership function is defined based on the decision making's allowable error. Then, the weight model based on the maximal satisfactory consistency idea is suggested, and the consistency index is put forward. Moreover, the weight distributing value model is developed to solve the decision making misleading problem since the multioptimization solutions in the former model. Finally, the weights are ranked based on the possibility degree approach to obtain the ultimate order.
Institute of Scientific and Technical Information of China (English)
孙孝前; 尤进红
2003-01-01
In this paper we consider the estimating problem of a semiparametric regression modelling whenthe data are longitudinal. An iterative weighted partial spline least squares estimator (IWPSLSE) for the para-metric component is proposed which is more efficient than the weighted partial spline least squares estimator(WPSLSE) with weights constructed by using the within-group partial spline least squares residuals in the senseof asymptotic variance. The asymptotic normality of this IWPSLSE is established. An adaptive procedure ispresented which ensures that the iterative process stops after a finite number of iterations and produces anestimator asymptotically equivalent to the best estimator that can be obtained by using the iterative proce-dure. These results are generalizations of those in heteroscedastic linear model to the case of semiparametric regression.
Mandal, A; Neser, F W C; Roy, R; Rout, P K; Notter, D R
2009-02-01
Variance components and genetic parameters for greasy fleece weights of Muzaffarnagari sheep maintained at the Central Institute for Research on Goats, Makhdoom, Mathura, India, over a period of 29 years (1976 to 2004) were estimated by restricted maximum likelihood (REML), fitting six animal models including various combinations of maternal effects. Data on body weights at 6 (W6) and 12 months (W12) of age were also included in the study. Records of 2807 lambs descended from 160 rams and 1202 ewes were used for the study. Direct heritability estimates for fleece weight at 6 (FW6) and 12 months of age (FW12), and total fleece weights up to 1 year of age (TFW) were 0.14, 0.16 and 0.25, respectively. Maternal genetic and permanent environmental effects did not significantly influence any of the traits under study. Genetic correlations among fleece weights and body weights were obtained from multivariate analyses. Direct genetic correlations of FW6 with W6 and W12 were relatively large, ranging from 0.61 to 0.67, but only moderate genetic correlations existed between FW12 and W6 (0.39) and between FW12 and W12 (0.49). The genetic correlation between FW6 and FW12 was very high (0.95), but the corresponding phenotypic correlation was much lower (0.28). Heritability estimates for all traits were at least 0.15, indicating that there is potential for their improvement by selection. The moderate to high positive genetic correlations between fleece weights and body weights at 6 and 12 months of age suggest that some of the genetic factors that influence animal growth also influence wool growth. Thus selection to improve the body weights or fleece weights at 6 months of age will also result in genetic improvement of fleece weights at subsequent stages of growth.
Monaco, James P; Madabhushi, Anant
2012-12-01
Many estimation tasks require Bayesian classifiers capable of adjusting their performance (e.g. sensitivity/specificity). In situations where the optimal classification decision can be identified by an exhaustive search over all possible classes, means for adjusting classifier performance, such as probability thresholding or weighting the a posteriori probabilities, are well established. Unfortunately, analogous methods compatible with Markov random fields (i.e. large collections of dependent random variables) are noticeably absent from the literature. Consequently, most Markov random field (MRF) based classification systems typically restrict their performance to a single, static operating point (i.e. a paired sensitivity/specificity). To address this deficiency, we previously introduced an extension of maximum posterior marginals (MPM) estimation that allows certain classes to be weighted more heavily than others, thus providing a means for varying classifier performance. However, this extension is not appropriate for the more popular maximum a posteriori (MAP) estimation. Thus, a strategy for varying the performance of MAP estimators is still needed. Such a strategy is essential for several reasons: (1) the MAP cost function may be more appropriate in certain classification tasks than the MPM cost function, (2) the literature provides a surfeit of MAP estimation implementations, several of which are considerably faster than the typical Markov Chain Monte Carlo methods used for MPM, and (3) MAP estimation is used far more often than MPM. Consequently, in this paper we introduce multiplicative weighted MAP (MWMAP) estimation-achieved via the incorporation of multiplicative weights into the MAP cost function-which allows certain classes to be preferred over others. This creates a natural bias for specific classes, and consequently a means for adjusting classifier performance. Similarly, we show how this multiplicative weighting strategy can be applied to the MPM
Comparison of the accuracy of clinical methods for estimation of fetal weight
Directory of Open Access Journals (Sweden)
Haji Esmaeilou M
2016-01-01
Full Text Available Estimation of fetal weight (EFW is one of the essential measures for labor and delivery. While the use of ultrasonography for EFW is costly, may not work in some centers. So, to make a non- ultrasound method for EFW is important. This study aimed to compare the accuracy of various clinical methods for EFW with the actual birth weight at term pregnancy. A cross-sectional study conducted on 98 pregnant women who were admitted for delivery with gestational age of 37-42 weeks, singleton pregnancy and cephalic presentation in Imam Khomeini hospital, Ahvaz. The fetal weight was anticipated by a midwife through abdominal palpation (using Leopold's maneuvers, measurements of symphysis-fundal height and abdominal girth, and also three formulas. The results were analyzed using the software SPSS version 20 and SATA11. The actual average birth weight was3242.85±43.37 gr. A significant positive correlation was observed between actual birth weight and clinically estimated weight. Kappa coefficient was > 0.8 when all studied methods were compared with the actual weight. This agreement was greater on abdominal palpation and Risanto’s formula, respectively. In the present study, abdominal palpation and Risanto's formula are more accurate for predicting fetal weight. Since these methods are quick, simple and costeffective for EFW so, they can be a useful alternative instead of routine ultrasonography.
Zurlo de Mirotti, S M; Lesa, A M; Barrón de Carbonetti, M; Roitter, H; Villagra de Lacuara, S
1995-01-01
Our aim was to confirm in our environment what has been observed and described by other writers about the importance of achieving a "critical body weight'' and an adequate "fat percentage'' -on the basis of the calculation of total body water- for the initiation and development of pubertal events. This study included 92 girls, healthy, well nourished, belonging to upper middle class from a high school of The National University of Cordoba. The longitudinal method of control was used every 6 months and at the precise moment of menarche. Out of 20 antropometrical variables observed height, weight and height, TBW as percentage of body weight, lean body and fat weight, fat percentage and skin folds ppercentiles for each girl at menarche. A regression between fat percentage and skin folds was done. Percentiles 5 to 95 of fat percentage in relation to body water percentage were estimated. At menarche the average for the different variables are: Heigth 155.6 cm +/- 0.469; Weight 45.8 Kg +/- 0,5; TBW 25.216 lit. +/- 0.318; lean body weigth 35.02 Kg (S.D.2.98); fat weigth 10.86 Kg (S. D. 3.17). The addition of skin folds was correlated fat percentage, thus, an equation was obtained for the average calculation of such percentage %F= 12.16 + (0.313 x fold addition). The minium percentage for the onset of menstrual cycles is 17.3% and corresponds to percentile 10. However, there is a 5% of girls who start to menstruate with a 15.5% of fat and none of them is below that value. The reasons mentioned above suggest that is necessary to obtain a "critical body weigth'' as well as a "fat percentage'' minimum for the onset and maintenance of menstrual cycles, among our girls, similar o what has been obtained by doctor Frisch.
Factors affecting prenatal sonographic estimation of weight in extremely low birthweight infants.
Townsend, R R; Filly, R A; Callen, P W; Laros, R K
1988-04-01
Because critical management decisions are based on sonographic estimation of fetal weight in fetuses less than 1000 g, we sought to evaluate the accuracy of birthweight prediction in this range and to identify factors affecting this accuracy. Fetal weight was estimated using several published methods in 53 fetuses with birthweights less than 1000 g. Standard deviations greater than 12.3% indicate more random error in the sonographic weight prediction than has been reported in higher weight groups. No statistically significant differences were found between patient groups with decreased, normal, or increased amniotic fluid volume or portable examination. There was a trend toward lower mean deviation (2.9 vs 6.0%) and standard deviation (8.9 vs. 15.0%) in studies with scan quality judged "good" compared with "poor" based on ability to visualize anatomic landmarks.
Saarela, Olli; Liu, Zhihui Amy
2016-10-15
Marginal structural Cox models are used for quantifying marginal treatment effects on outcome event hazard function. Such models are estimated using inverse probability of treatment and censoring (IPTC) weighting, which properly accounts for the impact of time-dependent confounders, avoiding conditioning on factors on the causal pathway. To estimate the IPTC weights, the treatment assignment mechanism is conventionally modeled in discrete time. While this is natural in situations where treatment information is recorded at scheduled follow-up visits, in other contexts, the events specifying the treatment history can be modeled in continuous time using the tools of event history analysis. This is particularly the case for treatment procedures, such as surgeries. In this paper, we propose a novel approach for flexible parametric estimation of continuous-time IPTC weights and illustrate it in assessing the relationship between metastasectomy and mortality in metastatic renal cell carcinoma patients. Copyright © 2016 John Wiley & Sons, Ltd.
Kurugol, Sila; Freiman, Moti; Afacan, Onur; Domachevsky, Liran; Perez-Rossello, Jeannette M; Callahan, Michael J; Warfield, Simon K
2015-01-01
Non-invasive characterization of water molecule's mobility variations by quantitative analysis of diffusion-weighted MRI (DW-MRI) signal decay in the abdomen has the potential to serve as a biomarker in gastrointestinal and oncological applications. Accurate and reproducible estimation of the signal decay model parameters is challenging due to the presence of respiratory, cardiac, and peristalsis motion. Independent registration of each b-value image to the b-value=0 s/mm(2) image prior to parameter estimation might be sub-optimal because of the low SNR and contrast difference between images of varying b-value. In this work, we introduce a motion-compensated parameter estimation framework that simultaneously solves image registration and model estimation (SIR-ME) problems by utilizing the interdependence of acquired volumes along the diffusion weighting dimension. We evaluated the improvement in model parameters estimation accuracy using 16 in-vivo DW-MRI data sets of Crohn's disease patients by comparing parameter estimates obtained using the SIR-ME model to the parameter estimates obtained by fitting the signal decay model to the acquired DW-MRI images. The proposed SIR-ME model reduced the average root-mean-square error between the observed signal and the fitted model by more than 50%. Moreover, the SIR-ME model estimates discriminate between normal and abnormal bowel loops better than the standard parameter estimates.
Estimating the Effects of Obesity and Weight Change on Mortality Using a Dynamic Causal Model
Bochen Cao
2015-01-01
Background A well-known challenge in estimating the mortality risks of obesity is reverse causality attributable to illness-associated and smoking-associated weight loss. Given that the likelihood of chronic and acute illnesses rises with age, reverse causality is most threatening to estimates derived from elderly populations. Methods I analyzed data from 12,523 respondents over 50 years old from a nationally representative longitudinal dataset, the Health and Retirement Study (HRS). The effe...
Bachmann, Sebastian; Neufeld, Roman; Dzemski, Martin; Stalke, Dietmar
2016-06-13
New external calibration curves (ECCs) for the estimation of aggregation states of small molecules in solution by DOSY NMR spectroscopy for a range of different common NMR solvents ([D6 ]DMSO, C6 D12 , C6 D6 , CDCl3 , and CD2 Cl2 ) are introduced and applied. ECCs are of avail to estimate molecular weights (MWs) from diffusion coefficients of previously unknown aggregates. This enables a straightforward and elaborate examination of (de)aggregation phenomena in solution.
King, J. R.; McPhie, R. P.
2015-05-01
The spotted ratfish (Hydrolagus colliei) is a chimaeroid ranging from southeast Alaska to Baja California and found at depths of up to 1029 m. Despite being widespread and ubiquitous, few biological parameter estimates exist for spotted ratfish due to a lack of suitable ageing structures to estimate age and growth. We present preliminary results of age, growth and maturity estimates based on a new method in which tritor ridges are counted on the vomerine tooth plate. We also provide a method for estimating the number of worn tritor ridges based on tooth plate diameter measurements for the spotted ratfish. The tritor ridges are distinct bumps that are easy to identify and precision estimates between readers suggests that this method is transferable. Tritor ridges are a potential structure for estimating age in H. colliei and we provide recommendations for future research to improve the method. We sampled 269 spotted ratfish captured in trawl surveys off the coast British Columbia ranging in size from 74 to 495 mm in precaudal length (PCL). The estimated ages ranged from 2 to 16 years for males and from 2 to 21 years for females. The von Bertalanffy, von Bertalanffy with known size at birth, Gompertz and logistic growth models were fitted to the data. Based on Akaike information criterion corrected for sample size and number of parameters estimated, the logistic growth curve was selected as most suitable. The logistic growth model yielded the following parameter estimates: Linf=407.22 mm (PCL), k=0.23 year-1, t0=-7.06 years for males; L∞=494.52 mm (PCL), k=0.26 year-1, t0=-8.35 years for females. Estimated ages at 50% maturity were 12 and 14 years for males and females, respectively. Correspondingly, the size at 50% maturity estimates was smaller for males (302 mm, PCL) than females (393 mm, PCL). Both estimates are larger than those made for spotted ratfish off of California indicating regional differences in life history traits for this species. Our preliminary
Reliability-Based Weighting of Visual and Vestibular Cues in Displacement Estimation.
ter Horst, Arjan C; Koppen, Mathieu; Selen, Luc P J; Medendorp, W Pieter
2015-01-01
When navigating through the environment, our brain needs to infer how far we move and in which direction we are heading. In this estimation process, the brain may rely on multiple sensory modalities, including the visual and vestibular systems. Previous research has mainly focused on heading estimation, showing that sensory cues are combined by weighting them in proportion to their reliability, consistent with statistically optimal integration. But while heading estimation could improve with the ongoing motion, due to the constant flow of information, the estimate of how far we move requires the integration of sensory information across the whole displacement. In this study, we investigate whether the brain optimally combines visual and vestibular information during a displacement estimation task, even if their reliability varies from trial to trial. Participants were seated on a linear sled, immersed in a stereoscopic virtual reality environment. They were subjected to a passive linear motion involving visual and vestibular cues with different levels of visual coherence to change relative cue reliability and with cue discrepancies to test relative cue weighting. Participants performed a two-interval two-alternative forced-choice task, indicating which of two sequentially perceived displacements was larger. Our results show that humans adapt their weighting of visual and vestibular information from trial to trial in proportion to their reliability. These results provide evidence that humans optimally integrate visual and vestibular information in order to estimate their body displacement.
Energy Technology Data Exchange (ETDEWEB)
Korbin, G.; Wollenberg, H.; Wilson, C.; Strisower, B.; Chan, T.; Wedge, D.
1981-09-01
Plans for an underground research facility are presented, incorporating techniques to assess the hydrological and thermomechanical response of a rock mass to the introduction and long-term isolation of radioactive waste, and to assess the effects of excavation on the hydrologic integrity of a repository and its subsequent backfill, plugging, and sealing. The project is designed to utilize existing mine or civil works for access to experimental areas and is estimated to last 8 years at a total cost for contruction and operation of $39.0 million (1981 dollars). Performing the same experiments in an existing underground research facility would reduce the duration to 7-1/2 years and cost $27.7 million as a lower-bound estimate. These preliminary plans and estimates should be revised after specific sites are identified which would accommodate the facility.
DEFF Research Database (Denmark)
Pedersen, Mads Møller; Pihl, Michael Johannes; Haugaard, Per
2011-01-01
angles and std were calculated { 52±18 ; 55±23 ; 60±16 }°. Spectral angles { 52 ; 56 ; 52 }° were obtained from the B-mode images. Obtained values are: PSTO { 76±15 ; 89±28 ; 77±7 } cm/s, spectral PS { 77 ; 110 ; 76 } cm/s, EDTO { 10±3 ; 14±8 ; 15±3 } cm/s, spectral ED { 18 ; 13 ; 20 } cm/s, RITO { 0.......87±0.05 ; 0.79±0.21 ; 0.79±0.06 }, and spectral RI { 0.77 ; 0.88 ; 0.73 }. Vector angles are within ±two std of the spectral angle. TO velocity estimates are within ±three std of the spectral estimates. RITO are within ±two std of the spectral estimates. Preliminary data indicates that the TO and spectral...
Pedersen, Mads Møller; Pihl, Michael Johannes; Haugaard, Per; Hansen, Jens Munk; Lindskov Hansen, Kristoffer; Bachmann Nielsen, Michael; Jensen, Jørgen Arendt
2011-03-01
Spectral velocity estimation is considered the gold standard in medical ultrasound. Peak systole (PS), end diastole (ED), and resistive index (RI) are used clinically. Angle correction is performed using a flow angle set manually. With Transverse Oscillation (TO) velocity estimates the flow angle, peak systole (PSTO), end diastole (EDTO), and resistive index (RITO) are estimated. This study investigates if these clinical parameters are estimated equally good using spectral and TO data. The right common carotid arteries of three healthy volunteers were scanned longitudinally. Average TO flow angles and std were calculated { 52+/-18 ; 55+/-23 ; 60+/-16 }°. Spectral angles { 52 ; 56 ; 52 }° were obtained from the B-mode images. Obtained values are: PSTO { 76+/-15 ; 89+/-28 ; 77+/-7 } cm/s, spectral PS { 77 ; 110 ; 76 } cm/s, EDTO { 10+/-3 ; 14+/-8 ; 15+/-3 } cm/s, spectral ED { 18 ; 13 ; 20 } cm/s, RITO { 0.87+/-0.05 ; 0.79+/-0.21 ; 0.79+/-0.06 }, and spectral RI { 0.77 ; 0.88 ; 0.73 }. Vector angles are within +/-two std of the spectral angle. TO velocity estimates are within +/-three std of the spectral estimates. RITO are within +/-two std of the spectral estimates. Preliminary data indicates that the TO and spectral velocity estimates are equally good. With TO there is no manual angle setting and no flow angle limitation. TO velocity estimation can also automatically handle situations where the angle varies over the cardiac cycle. More detailed temporal and spatial vector estimates with diagnostic potential are available with the TO velocity estimation.
Estimates for Vector-valued Commutators on Weighted Morrey Space and Applications
Institute of Scientific and Technical Information of China (English)
Shao Guang SHI
2013-01-01
In this paper,we introduce weighted vector-valued Morrey spaces and obtain some estimates for vector-valued commutators on these spaces.Applications to Calderón-Zygmund singular integral operators,oscillatory singular integral operators and parabolic difference equations are considered.
Uniform estimate for maximum of randomly weighted sums with applications to insurance risk theory
Institute of Scientific and Technical Information of China (English)
WANG Dingcheng; SU Chun; ZENG Yong
2005-01-01
This paper obtains the uniform estimate for maximum of sums of independent and heavy-tailed random variables with nonnegative random weights, which can be arbitrarily dependent of each other. Then the applications to ruin probabilities in a discrete time risk model with dependent stochastic returns are considered.
Kushwaha, B P; Mandal, A; Arora, A L; Kumar, R; Kumar, S; Notter, D R
2009-08-01
Estimates of (co)variance components were obtained for weights at birth, weaning and 6, 9 and 12 months of age in Chokla sheep maintained at the Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, India, over a period of 21 years (1980-2000). Records of 2030 lambs descended from 150 rams and 616 ewes were used in the study. Analyses were carried out by restricted maximum likelihood (REML) fitting an animal model and ignoring or including maternal genetic or permanent environmental effects. Six different animal models were fitted for all traits. The best model was chosen after testing the improvement of the log-likelihood values. Direct heritability estimates were inflated substantially for all traits when maternal effects were ignored. Heritability estimates for weight at birth, weaning and 6, 9 and 12 months of age were 0.20, 0.18, 0.16, 0.22 and 0.23, respectively in the best models. Additive maternal and maternal permanent environmental effects were both significant at birth, accounting for 9% and 12% of phenotypic variance, respectively, but the source of maternal effects (additive versus permanent environmental) at later ages could not be clearly identified. The estimated repeatabilities across years of ewe effects on lamb body weights were 0.26, 0.14, 0.12, 0.13, and 0.15 at birth, weaning, 6, 9 and 12 months of age, respectively. These results indicate that modest rates of genetic progress are possible for all weights.
Estimation Normal Vector of Triangular Mesh Vertex by Angle and Centroid Weights and its Application
Directory of Open Access Journals (Sweden)
Yueping Chen
2013-04-01
Full Text Available To compute vertex normal of triangular meshes more accurately, this paper presents an improved algorithm based on angle and centroid weights. Firstly, four representational algorithms are analyzed by comparing their weighting characteristics such as angles, areas and centroids. The drawbacks of each algorithm are discussed. Following that, an improved algorithm is put forward based on angle and centroid weights. Finally, by taking the deviation angle between the nominal normal vector and the estimated one as the error evaluation standard factor, the triangular mesh models of spheres, ellipsoids, paraboloids and cylinders are used to analyze the performance of all these estimation algorithms. The machining and inspection operations of one mould part are conducted to verify the improved algorithm. Experimental results demonstrate that the algorithm is effective.
Wahba, Grace; Deepak, A. (Editor)
1988-01-01
The problem of merging direct and remotely sensed (indirect) data with forecast data to get an estimate of the present state of the atmosphere for the purpose of numerical weather prediction is examined. To carry out this merging optimally, it is necessary to provide an estimate of the relative weights to be given to the observations and forecast. It is possible to do this dynamically from the information to be merged, if the correlation structure of the errors from the various sources is sufficiently different. Some new statistical approaches to doing this are described, and conditions quantified in which such estimates are likely to be good.
Estimating and verifying soil unit weight determined on the basis of SCPTu tests
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Bagińska Irena
2016-09-01
Full Text Available The unit weight, as a basic physical feature of soil, is an elementary quantity, and knowledge of this parameter is necessary in each geotechnical and geo-engineering task. Estimation of this quantity can be made with both laboratory and field techniques. The paper comprises a multi-scale evaluation of unit weight of cohesive soil, based on several measurements made in nearby locations using the SCPTu static probe. The procedures used were based on the two classifications and two solutions from literature. The results were referenced to the actual values of unit weight determined with a direct procedure from undisturbed samples. The resulting solutions were the basis for proposing a new formula to determine the soil unit weight from SCPTu measurements, as well as comparative analysis using exemplary values taken from the national Polish standard.
Interpolation method for live weight estimation based on age in Japanese quails
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Senol Celik
Full Text Available ABSTRACT The objective of this study was to demonstrate live weight estimation based on age by using Newton Interpolation method for male and female quails for seven weeks of fattening. A total of 138-day-old quail chicks were used in the study. The study demonstrated a 6th-degree polynomial interpolation for the function values obtained at seven equal intervals from 7 to 49 days. Live weight increase prediction was calculated for male and female quails between the 7th and 49th days using Newton Interpolation. Daily live weight increase for male and female quails based on observed live weights was determined. Female quails displayed more live weight increase after the 19th day compared with males. Average live weight increase in male quails was 3.81 g, and 4.63 g for females until the 49th day. The highest live weight increase was observed during the fourth week for all quails. Sum of squared errors and coefficient of determination (R2 for fit of the model were calculated and the F test was performed. F, sum of squared errors, and R2 obtained by Newton Interpolation for male quails and female quail were very large: 0 (approximately zero and 0.999, respectively. The interpolation method is suitable for breeding studies.
Applying fuzzy logic to estimate the parameters of the length-weight relationship.
Bitar, S D; Campos, C P; Freitas, C E C
2016-05-03
We evaluated three mathematical procedures to estimate the parameters of the relationship between weight and length for Cichla monoculus: least squares ordinary regression on log-transformed data, non-linear estimation using raw data and a mix of multivariate analysis and fuzzy logic. Our goal was to find an alternative approach that considers the uncertainties inherent to this biological model. We found that non-linear estimation generated more consistent estimates than least squares regression. Our results also indicate that it is possible to find consistent estimates of the parameters directly from the centers of mass of each cluster. However, the most important result is the intervals obtained with the fuzzy inference system.
Distributed weighted least-squares estimation with fast convergence for large-scale systems.
Marelli, Damián Edgardo; Fu, Minyue
2015-01-01
In this paper we study a distributed weighted least-squares estimation problem for a large-scale system consisting of a network of interconnected sub-systems. Each sub-system is concerned with a subset of the unknown parameters and has a measurement linear in the unknown parameters with additive noise. The distributed estimation task is for each sub-system to compute the globally optimal estimate of its own parameters using its own measurement and information shared with the network through neighborhood communication. We first provide a fully distributed iterative algorithm to asymptotically compute the global optimal estimate. The convergence rate of the algorithm will be maximized using a scaling parameter and a preconditioning method. This algorithm works for a general network. For a network without loops, we also provide a different iterative algorithm to compute the global optimal estimate which converges in a finite number of steps. We include numerical experiments to illustrate the performances of the proposed methods.
Inverse probability of censoring weighted estimates of Kendall's τ for gap time analyses.
Lakhal-Chaieb, Lajmi; Cook, Richard J; Lin, Xihong
2010-12-01
In life history studies, interest often lies in the analysis of the interevent, or gap times and the association between event times. Gap time analyses are challenging however, even when the length of follow-up is determined independently of the event process, because associations between gap times induce dependent censoring for second and subsequent gap times. This article discusses nonparametric estimation of the association between consecutive gap times based on Kendall's τ in the presence of this type of dependent censoring. A nonparametric estimator that uses inverse probability of censoring weights is provided. Estimates of conditional gap time distributions can be obtained following specification of a particular copula function. Simulation studies show the estimator performs well and compares favorably with an alternative estimator. Generalizations to a piecewise constant Clayton copula are given. Several simulation studies and illustrations with real data sets are also provided.
Effect of Temporal Residual Correlation on Estimation of Model Averaging Weights
Ye, M.; Lu, D.; Curtis, G. P.; Meyer, P. D.; Yabusaki, S.
2010-12-01
When conducting model averaging for assessing groundwater conceptual model uncertainty, the averaging weights are always calculated using model selection criteria such as AIC, AICc, BIC, and KIC. However, this method sometimes leads to an unrealistic situation in which one model receives overwhelmingly high averaging weight (even 100%), which cannot be justified by available data and knowledge. It is found in this study that the unrealistic situation is due partly, if not solely, to ignorance of residual correlation when estimating the negative log-likelihood function common to all the model selection criteria. In the context of maximum-likelihood or least-square inverse modeling, the residual correlation is accounted for in the full covariance matrix; when the full covariance matrix is replaced by its diagonal counterpart, it assumes data independence and ignores the correlation. As a result, treating the correlated residuals as independent distorts the distance between observations and simulations of alternative models. As a result, it may lead to incorrect estimation of model selection criteria and model averaging weights. This is illustrated for a set of surface complexation models developed to simulate uranium transport based on a series of column experiments. The residuals are correlated in time, and the time correlation is addressed using a second-order autoregressive model. The modeling results reveal importance of considering residual correlation in the estimation of model averaging weights.
ESTIMATION OF LIVE BODY WEIGHT FROM LINEAR BODY MEASUREMENTS FOR FARTA SHEEP
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MENGISTIE TAYE
2012-01-01
Full Text Available A study, to develop regression models for prediction of body weight from other linear body measurements, was conducted in Esite, Farta and Lai-Gaint districts of South Gondar, Amhara region. Records on body weight (BW and other linear body measurements (Body Length (BL, Wither Height (WH, Chest Girth (CH, Pelvic Width (PW and Ear Length (EL were taken from 941 sheep. Non-linear, simple linear and multiple linear regression models were developed using Statistical Package for Social Sciences (SPSS version 12.0. For the multiple linear regressions, step-wise regression procedures were used. Predicting models were developed for different age, sex and for the pool. Positive and significant (P<0.01 correlations were observed between body weight and linear body measurements for all sex and age groups. Among the four linear body measurements, heart girth had the highest correlation coefficient (except ear length in all age and sex groups which is followed by body length, height at wither and pelvic width. Heart girth was the first variable to explain more variation than other variables in both sex and age groups. The models developed had a coefficient of determination of 0.26 to 0.89; the highest coefficient of determination was depicted for male while the lowest was for dentition groups having two permanent incisors. Regression models in general were poor in explaining weight for the dentition groups above one pair of permanent incisors. Heart girth alone was able to estimate weight with a coefficient of determination of 0.77, for both sexes and the pool. The coefficient of determination of the fitted equations (in general decreased as the age of sheep advances indicating that the fitted equations can predict weight for younger sheep with better accuracy than for older ones. In general, much of the variation in weight was explained when many traits were included in the model. However, for ease of use and to avoid complexity at field condition, it is
A Weighted Least-Squares Approach to Parameter Estimation Problems Based on Binary Measurements
Colinet, Eric; Juillard, Jérôme
2010-01-01
We present a new approach to parameter estimation problems based on binary measurements, motivated by the need to add integrated low-cost self-test features to microfabricated devices. This approach is based on the use of original weighted least-squares criteria: as opposed to other existing methods, it requires no dithering signal and it does not rely on an approximation of the quantizer. In this paper, we focus on a simple choice for the weights and establish some asymptotical properties of...
Shin, Yoonseok
2015-01-01
Among the recent data mining techniques available, the boosting approach has attracted a great deal of attention because of its effective learning algorithm and strong boundaries in terms of its generalization performance. However, the boosting approach has yet to be used in regression problems within the construction domain, including cost estimations, but has been actively utilized in other domains. Therefore, a boosting regression tree (BRT) is applied to cost estimations at the early stage of a construction project to examine the applicability of the boosting approach to a regression problem within the construction domain. To evaluate the performance of the BRT model, its performance was compared with that of a neural network (NN) model, which has been proven to have a high performance in cost estimation domains. The BRT model has shown results similar to those of NN model using 234 actual cost datasets of a building construction project. In addition, the BRT model can provide additional information such as the importance plot and structure model, which can support estimators in comprehending the decision making process. Consequently, the boosting approach has potential applicability in preliminary cost estimations in a building construction project.
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Yoonseok Shin
2015-01-01
Full Text Available Among the recent data mining techniques available, the boosting approach has attracted a great deal of attention because of its effective learning algorithm and strong boundaries in terms of its generalization performance. However, the boosting approach has yet to be used in regression problems within the construction domain, including cost estimations, but has been actively utilized in other domains. Therefore, a boosting regression tree (BRT is applied to cost estimations at the early stage of a construction project to examine the applicability of the boosting approach to a regression problem within the construction domain. To evaluate the performance of the BRT model, its performance was compared with that of a neural network (NN model, which has been proven to have a high performance in cost estimation domains. The BRT model has shown results similar to those of NN model using 234 actual cost datasets of a building construction project. In addition, the BRT model can provide additional information such as the importance plot and structure model, which can support estimators in comprehending the decision making process. Consequently, the boosting approach has potential applicability in preliminary cost estimations in a building construction project.
Estimated weight on goats with a commercial weighing tape and thoracic perimeter.
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Pablo Chacón-Hernández
2016-12-01
Full Text Available The objective of this paper was to determine the technical viability of using a weighing tape to measure the pectoral circumference and estimate the body weight of goats. The study took place in the Alfredo Volio Mata Experimental Station in the University of Costa Rica, during the month of February 2015, by measuring the weight with a scale, a calibrated weighing tape and the thoracic diameter of sixty female goats. The data was adjusted through polynomial equations from rst to third degree. The thoracic diameter was used to determine the living weight of the goat population analyzed. Signi cant differences were found (p<0,05 when using the calibrated tape and the scale to determine the weight, with the obtained values of an average of 48,62kg y 39,99kg, respectively. There were differences (p<0,05 in the average of the weight depending on the age with results of 24,40kg in animals less than a year old, 40,39kg for the ages from one to three and 57,25kg for animals older with more than three years of age. The rst degree lineal regression, presented a good adjustment in the thoracic diameter and living weight( r2 = 0,88, with the values of ß0 and ß1 of -50,84 y 1,11, respectively.
A Preliminary Observation of Weight Loss Following Left Gastric Artery Embolization in Humans
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Andrew J. Gunn
2014-01-01
Full Text Available Background/Objectives. Embolization of the left gastric artery (LGA, which preferentially supplies the gastric fundus, has been shown to produce weight loss in animal models. However, weight loss after LGA embolization in humans has not been previously established. The aim of this study was to evaluate postprocedural weight loss in patients following LGA embolization. Subjects/Methods. A retrospective analysis of the medical records of patients who underwent LGA embolization for upper gastrointestinal (GI bleeding was performed. Postprocedural weight loss in this group was compared to a control group of patients who had undergone embolization of other arteries for upper GI bleeding. Results. The experimental group (N=19 lost an average of 7.3% of their initial body weight within three months of LGA embolization, which was significantly greater than the 2% weight loss observed in the control group (N=28 (P=0.006. No significant differences were seen between the groups in preprocedural body mass index (BMI, age, postprocedural care in the intensive care unit, history of malignancy, serum creatinine, or left ventricular ejection fraction. Conclusions. The current data suggest that body weight in humans may be modulated via LGA embolization. Continued research is warranted with prospective studies to further investigate this phenomenon.
Preliminary experiments to estimate the PE.MA.M (PElagic MArine Mesocosm) offshore behaviour
Albani, Marta; Piermattei, Viviana; Stefanì, Chiara; Marcelli, Marco
2016-04-01
The phytoplankton community is controlled not only by local environmental conditions but also by physical processes occurring on different temporal and spatial scales. Hydrodynamic local conditions play an important role in marine ecosystems. Several studies have shown that hydrodynamic conditions can influence the phytoplankton settling velocity, vertical and horizontal distribution and formation of cyanobacterial blooms. Mesocosms are useful structures to simulate marine environment at mesoscale resolution; allowing to closely approximate biotic or abiotic parameters of interest directly in nature. In this work an innovative structure named PE.MA.M (PElagic MArine Mesocosm) is presented and tested. Laboratory experiments have been conducted in order to observe seasonal variations of biomass behaviour in two different hydrodynamic conditions: outside as well as whithin the PE.MA.M. We have evaluated whether it is possible to isolate a natural system from external water mass hydrodynamic exchanges and to assume that phytoplankton cells' transition is limited at the net and sea interface. Preliminary experiments test the isolating capacity of the net, to determine the currents' attenuation rate and to estimate the possible PE.MA.M. offshore behaviour. In the first investigation, we monitored the diffusion of phytoplankton cells. The PE.MA.M. exterior and interior were simulated using a plexiglass tank divided into two half-tanks (Aout-Bin) by a septum consisting of a net like a PE.MA.M. The tank was filled up with 10 L of water and only the half-tank Aout was filled up with 10 ml of phytoplankton culture (Clorella sp.). We monitored the chlorophyll concentrations for 24 hours. The two tanks had similar concentrations after 4 hours (2.70322 mg/m³ Aout and 2.37245 mg/m3 Bin) and this constant relationship was maintened until the end of the test. In the second investigation we used clod cards to measure water motions.We conducted two experiments within tank, the first
Polar Metric-Weighted Norm-Based Scan Matching for Robot Pose Estimation
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Guanglei Huo
2016-01-01
Full Text Available A novel point-to-point scan matching approach is proposed to address pose estimation and map building issues of mobile robots. Polar Scan Matching (PSM and Metric-Based Iterative Closest Point (Mb-ICP are usually employed for point-to-point scan matching tasks. However, due to the facts that PSM considers the distribution similarity of polar radii in irrelevant region of reference and current scans and Mb-ICP assumes a constant weight in the norm about rotation angle, they may lead to a mismatching of the reference and current scan in real-world scenarios. In order to obtain better match results and accurate estimation of the robot pose, we introduce a new metric rule, Polar Metric-Weighted Norm (PMWN, which takes both rotation and translation into account to match the reference and current scan. For robot pose estimation, the heading rotation angle is estimated by correspondences establishing results and further corrected by an absolute-value function, and then the geometric property of PMWN called projected circle is used to estimate the robot translation. The extensive experiments are conducted to evaluate the performance of PMWN-based approach. The results show that the proposed approach outperforms PSM and Mb-ICP in terms of accuracy, efficiency, and loop closure error of mapping.
Lin, Bangjiang; Li, Yiwei; Zhang, Shihao; Tang, Xuan
2015-10-01
Weighted interframe averaging (WIFA)-based channel estimation (CE) is presented for orthogonal frequency division multiplexing passive optical network (OFDM-PON), in which the CE results of the adjacent frames are directly averaged to increase the estimation accuracy. The effectiveness of WIFA combined with conventional least square, intrasymbol frequency-domain averaging, and minimum mean square error, respectively, is demonstrated through 26.7-km standard single-mode fiber transmission. The experimental results show that the WIFA method with low complexity can significantly enhance transmission performance of OFDM-PON.
Institute of Scientific and Technical Information of China (English)
Ge-mai Chen; Jin-hong You
2005-01-01
Consider a repeated measurement partially linear regression model with an unknown vector pasemiparametric generalized least squares estimator (SGLSE) ofβ, we propose an iterative weighted semiparametric least squares estimator (IWSLSE) and show that it improves upon the SGLSE in terms of asymptotic covariance matrix. An adaptive procedure is given to determine the number of iterations. We also show that when the number of replicates is less than or equal to two, the IWSLSE can not improve upon the SGLSE.These results are generalizations of those in [2] to the case of semiparametric regressions.
Weighted LS-SVM for function estimation applied to artifact removal in bio-signal processing.
Caicedo, Alexander; Van Huffel, Sabine
2010-01-01
Weighted LS-SVM is normally used for function estimation from highly corrupted data in order to decrease the impact of outliers. However, this method is limited in size and big time series should be segmented in smaller groups. Therefore, border discontinuities represent a problem in the final estimated function. Several methods such as committee networks or multilayer networks of LS-SVMs are used to address this problem, but these methods require extra training and hence the computational cost is increased. In this paper a technique that includes an extra weight vector in the formulation of the cost function for the LS-SVM problem is proposed as an alternative solution. The method is then applied to the removal of some artifacts in biomedical signals.
An Object-Oriented Computer Code for Aircraft Engine Weight Estimation
Tong, Michael T.; Naylor, Bret A.
2009-01-01
Reliable engine-weight estimation at the conceptual design stage is critical to the development of new aircraft engines. It helps to identify the best engine concept amongst several candidates. At NASA Glenn Research Center (GRC), the Weight Analysis of Turbine Engines (WATE) computer code, originally developed by Boeing Aircraft, has been used to estimate the engine weight of various conceptual engine designs. The code, written in FORTRAN, was originally developed for NASA in 1979. Since then, substantial improvements have been made to the code to improve the weight calculations for most of the engine components. Most recently, to improve the maintainability and extensibility of WATE, the FORTRAN code has been converted into an object-oriented version. The conversion was done within the NASA's NPSS (Numerical Propulsion System Simulation) framework. This enables WATE to interact seamlessly with the thermodynamic cycle model which provides component flow data such as airflows, temperatures, and pressures, etc., that are required for sizing the components and weight calculations. The tighter integration between the NPSS and WATE would greatly enhance system-level analysis and optimization capabilities. It also would facilitate the enhancement of the WATE code for next-generation aircraft and space propulsion systems. In this paper, the architecture of the object-oriented WATE code (or WATE++) is described. Both the FORTRAN and object-oriented versions of the code are employed to compute the dimensions and weight of a 300-passenger aircraft engine (GE90 class). Both versions of the code produce essentially identical results as should be the case.
The influence of maternal body mass index on fetal weight estimation in twin pregnancy.
LENUS (Irish Health Repository)
Ryan, Helen M
2013-11-08
Sonographic estimation of fetal weight (EFW) is important in the management of high-risk pregnancies. The possibility that increased maternal body mass index (BMI) adversely affects EFW assessments in twin pregnancies is controversial. The aim of this study was to investigate the effect of maternal BMI on the accuracy of EFW assessments in twin gestations prospectively recruited for the ESPRiT (Evaluation of Sonographic Predictors of Restricted growth in Twins) study.
A weighted least-squares method for parameter estimation in structured models
Galrinho, Miguel; Rojas, Cristian R.; Hjalmarsson, Håkan
2014-01-01
Parameter estimation in structured models is generally considered a difficult problem. For example, the prediction error method (PEM) typically gives a non-convex optimization problem, while it is difficult to incorporate structural information in subspace identification. In this contribution, we revisit the idea of iteratively using the weighted least-squares method to cope with the problem of non-convex optimization. The method is, essentially, a three-step method. First, a high order least...
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B. Bayram
2006-01-01
Full Text Available Data concerning body measurements, milk yield and body weights data were analysed on 101 of Holstein Friesian cows. Phenotypic correlations indicated positive significant relations between estimated feed efficiency (EFE and milk yield as well as 4 % fat corrected milk yield, and between body measurements and milk yield. However, negative correlations were found between the EFE and body measurements indicating that the taller, longer, deeper and especially heavier cows were not to be efficient as smaller cows
Jensen, J. K.; Wright, R. L.
1981-01-01
Estimates of total spacecraft weight and packaging options were made for three conceptual designs of a microwave radiometer spacecraft. Erectable structures were found to be slightly lighter than deployable structures but could be packaged in one-tenth the volume. The tension rim concept, an unconventional design approach, was found to be the lightest and transportable to orbit in the least number of shuttle flights.
Entropy Econometrics for combining regional economic forecasts: A Data-Weighted Prior Estimator
Fernández-Vázquez, Esteban; Moreno, Blanca
2017-08-01
Forecast combination has been studied in econometrics for a long time, and the literature has shown the superior performance of forecast combination over individual predictions. However, there is still controversy on which is the best procedure to specify the forecast weights. This paper explores the possibility of using a procedure based on Entropy Econometrics, which allows setting the weights for the individual forecasts as a mixture of different alternatives. In particular, we examine the ability of the Data-Weighted Prior Estimator proposed by Golan (J Econom 101(1):165-193, 2001) to combine forecasting models in a context of small sample sizes, a relative common scenario when dealing with time series for regional economies. We test the validity of the proposed approach using a simulation exercise and a real-world example that aims at predicting gross regional product growth rates for a regional economy. The forecasting performance of the Data-Weighted Prior Estimator proposed is compared with other combining methods. The simulation results indicate that in scenarios of heavily ill-conditioned datasets the approach suggested dominates other forecast combination strategies. The empirical results are consistent with the conclusions found in the numerical experiment.
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Siti Masitoh Kartikawati
2014-04-01
Full Text Available Pasak bumi (Eurycoma longifolia Jack is one of non timber forest products with “indeterminate” conservation status and commercially traded in West Kalimantan. The research objective was to determine the potential of pasak bumi root per hectare and its ecological condition under natural habitat. Root weight of E. longifolia Jack was estimated using simple linear regression and exponential equation with stem diameter and height as independent variables. The results showed that the individual number of the population was 114 with the majority in seedling stage with 71 individuals (62.28%. The distribution was found in clumped pattern. Conditions of the habitat could be described as follows: daily average temperature of 25.6oC, daily average relative humidity of 73.6%, light intensity of 0.9 klx, and red-yellow podsolic soil with texture ranged from clay to sandy clay. The selected estimator model for E. longifolia Jack root weight used exponential equation with stem height as independent variable using the equation of Y= 21.99T0,010 and determination coefficient of 0.97. After height variable was added, the potential of E. longifolia Jack minimum root weight that could be harvested per hectare was 0.33 kg.Keywords: Eurycoma longifolia, habitat preference, distribution pattern, root weight
Noise variance estimation and optimal weight determination for GOCE gravity recovery
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J. Kusche
2003-01-01
Full Text Available In the course of level 2 data processing for the GOCE (Gravity Field and Steady–State Ocean Circulation Explorer satellite mission different streams of level 1b data will be merged in a single solution providing the Earth’s gravity field, but also state-vector parameters and other quantities. A proper weighting of orbit tracking data, gravity gradiometry data and certain a priori information, usually considered as ‘solution constraints’, can be expected as crucial for the solution quality. But the a priori stochastic models, based on pre–mission assessment of the expected instrument behaviour, may be over–optimistic or even too pessimistic since they refer to an unprecedented mission with scientific payload never tested in space. One way to derive an optimal weighting scheme on a statistically sound basis while simultaneously validating the stochastic noise levels of the data is by including variance component estimation as a part of the level 1b to level 2 data analysis process. The idea is that by applying Monte-Carlo techniques this method can be extended to a large-scale problem like GOCE data analysis, using software modules that already exist or are currently under development. The proposed method has been tested using simulated GOCE orbit trajectories as well as gravity gradiometry data corrupted by colored random noise.Key words. GOCE, gravity field modelling, combination solutions, weight estimation, variance component estimation
Bayesian Prediction Model Based on Attribute Weighting and Kernel Density Estimations
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Zhong-Liang Xiang
2015-01-01
Full Text Available Although naïve Bayes learner has been proven to show reasonable performance in machine learning, it often suffers from a few problems with handling real world data. First problem is conditional independence; the second problem is the usage of frequency estimator. Therefore, we have proposed methods to solve these two problems revolving around naïve Bayes algorithms. By using an attribute weighting method, we have been able to handle conditional independence assumption issue, whereas, for the case of the frequency estimators, we have found a way to weaken the negative effects through our proposed smooth kernel method. In this paper, we have proposed a compact Bayes model, in which a smooth kernel augments weights on likelihood estimation. We have also chosen an attribute weighting method which employs mutual information metric to cooperate with the framework. Experiments have been conducted on UCI benchmark datasets and the accuracy of our proposed learner has been compared with that of standard naïve Bayes. The experimental results have demonstrated the effectiveness and efficiency of our proposed learning algorithm.
Gastounioti, Aimilia; Keller, Brad M.; Hsieh, Meng-Kang; Conant, Emily F.; Kontos, Despina
2016-03-01
Growing evidence suggests that quantitative descriptors of the parenchymal texture patterns hold a valuable role in assessing an individual woman's risk for breast cancer. In this work, we assess the hypothesis that breast cancer risk factors are not uniformly expressed in the breast parenchymal tissue and, therefore, breast-anatomy-weighted parenchymal texture descriptors, where different breasts ROIs have non uniform contributions, may enhance breast cancer risk assessment. To this end, we introduce an automated breast-anatomy-driven methodology which generates a breast atlas, which is then used to produce a weight map that reinforces the contributions of the central and upper-outer breast areas. We incorporate this methodology to our previously validated lattice-based strategy for parenchymal texture analysis. In the framework of a pilot case-control study, including digital mammograms from 424 women, our proposed breast-anatomy-weighted texture descriptors are optimized and evaluated against non weighted texture features, using regression analysis with leave-one-out cross validation. The classification performance is assessed in terms of the area under the curve (AUC) of the receiver operating characteristic. The collective discriminatory capacity of the weighted texture features was maximized (AUC=0.87) when the central breast area was considered more important than the upperouter area, with significant performance improvement (DeLong's test, p-valuepersonalized recommendations regarding women's cancer risk evaluation.
Broiler weight estimation based on machine vision and artificial neural network.
Amraei, S; Abdanan Mehdizadeh, S; Salari, S
2017-04-01
1. Machine vision and artificial neural network (ANN) procedures were used to estimate live body weight of broiler chickens in 30 1-d-old broiler chickens reared for 42 d. 2. Imaging was performed two times daily. To localise chickens within the pen, an ellipse fitting algorithm was used and the chickens' head and tail removed using the Chan-Vese method. 3. The correlations between the body weight and 6 physical extracted features indicated that there were strong correlations between body weight and the 5 features including area, perimeter, convex area, major and minor axis length. 5. According to statistical analysis there was no significant difference between morning and afternoon data over 42 d. 6. In an attempt to improve the accuracy of live weight approximation different ANN techniques, including Bayesian regulation, Levenberg-Marquardt, Scaled conjugate gradient and gradient descent were used. Bayesian regulation with R(2) value of 0.98 was the best network for prediction of broiler weight. 7. The accuracy of the machine vision technique was examined and most errors were less than 50 g.
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Bangyan Zhu
2016-07-01
Full Text Available Spatial and temporal variations in the vertical stratification of the troposphere introduce significant propagation delays in interferometric synthetic aperture radar (InSAR observations. Observations of small amplitude surface deformations and regional subsidence rates are plagued by tropospheric delays, and strongly correlated with topographic height variations. Phase-based tropospheric correction techniques assuming a linear relationship between interferometric phase and topography have been exploited and developed, with mixed success. Producing robust estimates of tropospheric phase delay however plays a critical role in increasing the accuracy of InSAR measurements. Meanwhile, few phase-based correction methods account for the spatially variable tropospheric delay over lager study regions. Here, we present a robust and multi-weighted approach to estimate the correlation between phase and topography that is relatively insensitive to confounding processes such as regional subsidence over larger regions as well as under varying tropospheric conditions. An expanded form of robust least squares is introduced to estimate the spatially variable correlation between phase and topography by splitting the interferograms into multiple blocks. Within each block, correlation is robustly estimated from the band-filtered phase and topography. Phase-elevation ratios are multiply- weighted and extrapolated to each persistent scatter (PS pixel. We applied the proposed method to Envisat ASAR images over the Southern California area, USA, and found that our method mitigated the atmospheric noise better than the conventional phase-based method. The corrected ground surface deformation agreed better with those measured from GPS.
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Abdollahian Vahed
2016-12-01
Full Text Available Without a doubt optimum performance is possible in the context of a planned development project organized failure to comply with a standard patterndoes not guarantee when a project based on financial forecasts and with the required quality. in this study, based on the standards of project management enumerating the factors for implementation of a project the study is the flagship project of Ilam and finally the implementation of the project as stated in the standard are investigated. in this research project emphasizing the preliminary estimates (estimates and time and workload has been considered and compared to the existing. according to the research findings in 83 percent of projects, project was not according to preliminary financial estimates. 100% of projects have been wrong to predict the time and projects have progressed according to preliminary forecast and in 66 percent of projects supporting private sector investment and hinder the progress of the project is appropriate and the project framework was unchanged.
Beirle, Steffen; Hörmann, Christoph; Jöckel, Patrick; Liu, Song; Penning de Vries, Marloes; Pozzer, Andrea; Sihler, Holger; Valks, Pieter; Wagner, Thomas
2016-07-01
The STRatospheric Estimation Algorithm from Mainz (STREAM) determines stratospheric columns of NO2 which are needed for the retrieval of tropospheric columns from satellite observations. It is based on the total column measurements over clean, remote regions as well as over clouded scenes where the tropospheric column is effectively shielded. The contribution of individual satellite measurements to the stratospheric estimate is controlled by various weighting factors. STREAM is a flexible and robust algorithm and does not require input from chemical transport models. It was developed as a verification algorithm for the upcoming satellite instrument TROPOMI, as a complement to the operational stratospheric correction based on data assimilation. STREAM was successfully applied to the UV/vis satellite instruments GOME 1/2, SCIAMACHY, and OMI. It overcomes some of the artifacts of previous algorithms, as it is capable of reproducing gradients of stratospheric NO2, e.g., related to the polar vortex, and reduces interpolation errors over continents. Based on synthetic input data, the uncertainty of STREAM was quantified as about 0.1-0.2 × 1015 molecules cm-2, in accordance with the typical deviations between stratospheric estimates from different algorithms compared in this study.
Tanaka, Kumihiko; Sakata, Kouichi; Oishi, Mitsuhiro; Morimoto, Hideki; Nakada, Satoru; Uetani, Mirei; Nogawa, Kazuhiro; Suwazono, Yasushi
2010-10-01
The authors estimated the benchmark durations (BMDs) and their 95% lower confidence limit (BMDL) for the reference duration of shiftwork for weight gain. A 14-yr prospective cohort study was conducted in male workers at a Japanese steel company (n = 7254) who had received annual health check-ups between 1991 and 2005. The endpoints in the study were either a 5%, 7.5%, or 10% increase in body mass index (BMI) during the period of observation, compared to the BMI at entry. The association between the duration of shiftwork and weight gain was investigated using multivariate pooled logistic regression analyses with stepwise selection of covariates, including age, BMI measured during the study, drinking and smoking habits, and habitual exercise. The BMDL/BMD for shiftwork in subjects aged in their 40s or ≥50 yrs was estimated using benchmark responses (BMRs) of 5% or 10% and parameters for the duration of shiftwork and other covariates. For workers aged in their 40s, the BMDL/BMD for shiftwork with a BMR of 5% was 18.6/23.0 yrs (≥7.5%) and 16.9/19.4 yrs (≥10%). For workers aged ≥50 yrs, the BMDL/BMD with a BMR of 5% was 22.9/28.2 yrs (≥7.5%) and 20.6/23.6 yrs (≥10%). The reference duration of shiftwork that associated with weight gain was shown to be at least 17 yrs in middle-aged workers. Special attention should be paid to prevent weight gain at an earlier stage and not when this increase in weight has become apparent.
An improved Q estimation approach: the weighted centroid frequency shift method
Li, Jingnan; Wang, Shangxu; Yang, Dengfeng; Dong, Chunhui; Tao, Yonghui; Zhou, Yatao
2016-06-01
Seismic wave propagation in subsurface media suffers from absorption, which can be quantified by the quality factor Q. Accurate estimation of the Q factor is of great importance for the resolution enhancement of seismic data, precise imaging and interpretation, and reservoir prediction and characterization. The centroid frequency shift method (CFS) is currently one of the most commonly used Q estimation methods. However, for seismic data that contain noise, the accuracy and stability of Q extracted using CFS depend on the choice of frequency band. In order to reduce the influence of frequency band choices and obtain Q with greater precision and robustness, we present an improved CFS Q measurement approach—the weighted CFS method (WCFS), which incorporates a Gaussian weighting coefficient into the calculation procedure of the conventional CFS. The basic idea is to enhance the proportion of advantageous frequencies in the amplitude spectrum and reduce the weight of disadvantageous frequencies. In this novel method, we first construct a Gauss function using the centroid frequency and variance of the reference wavelet. Then we employ it as the weighting coefficient for the amplitude spectrum of the original signal. Finally, the conventional CFS is adopted for the weighted amplitude spectrum to extract the Q factor. Numerical tests of noise-free synthetic data demonstrate that the WCFS is feasible and efficient, and produces more accurate results than the conventional CFS. Tests for noisy synthetic data indicate that the new method has better anti-noise capability than the CFS. The application to field vertical seismic profile (VSP) data further demonstrates its validity5.
Goldfeld, K S
2014-03-30
Cost-effectiveness analysis is an important tool that can be applied to the evaluation of a health treatment or policy. When the observed costs and outcomes result from a nonrandomized treatment, making causal inference about the effects of the treatment requires special care. The challenges are compounded when the observation period is truncated for some of the study subjects. This paper presents a method of unbiased estimation of cost-effectiveness using observational study data that is not fully observed. The method-twice-weighted multiple interval estimation of a marginal structural model-was developed in order to analyze the cost-effectiveness of treatment protocols for advanced dementia residents living nursing homes when they become acutely ill. A key feature of this estimation approach is that it facilitates a sensitivity analysis that identifies the potential effects of unmeasured confounding on the conclusions concerning cost-effectiveness.
Energy Technology Data Exchange (ETDEWEB)
Gallegos, A.F.; Gonzales, G.J.; Bennett, K.D.; Pratt, L.E.
1997-02-01
The Record of Decision on the Dual Axis Radiographic Hydrodynamic Test Facility at the Los Alamos National Laboratory requires that the Department of Energy takes special precautions to protect the Mexican Spotted Owl (Strix occidentalis lucida). In order to do so, risk to the owl presented by radiological and nonradiological contaminants must be estimated. A preliminary risk assessment on the Mexican Spotted Owl in two Ecological Exposure Units (EEUs) was performed using a modified Environmental Protection Agency Quotient method, the FORTRAN model ECORSK4, and a geographic information system. Estimated doses to the owl under a spatially-weighted foraging regime were compared against toxicological reference doses generating hazard indices (HIs) and hazard quotients (HQs) for three risk source types. The average HI was 0.20 for EEU-21 and 0.0015 for EEU-40. Under the risk parameter assumptions made, hazard quotient results indicated no unacceptable risk to the owl, including a measure of cumulative effects from multiple contaminants that assumes a linear additive toxicity type. An HI of 1.0 was used as the evaluative criteria for determining the acceptability of risk. This value was exceeded (1.06) in only one of 200 simulated potential nest sites. Cesium-137, Ni, {sup 239}Pu, Al and {sup 234}U we`re among the constituents with the highest partial HQs. Improving model realism by weighting simulated owl foraging based on distance from potential nest sites decreased the estimated risk by 72% (0.5 HI units) for EEU-21 and by 97.6% (6.3E-02 HI units) for EEU-40. Information on risk by specific geographical location was generated, which can be used to manage contaminated areas, owl habitat, facility siting, and/or facility operations in order to maintain risk from contaminants at acceptably low levels.
PRELIMINARY RESULTS OF ESTIMATING SOIL MOISTURE OVER BARE SOIL USING FULL-POLARIMETRIC ALOS-2 DATA
Directory of Open Access Journals (Sweden)
A. Sekertekin
2016-10-01
Full Text Available Synthetic Aperture Radar (SAR imaging system is one of the most effective way for Earth observation. The aim of this study is to present the preliminary results about estimating soil moisture using L-band Synthetic Aperture Radar (SAR data. Full-polarimetric (HH, HV, VV, VH ALOS-2 data, acquired on 22.04.2016 with the incidence angle of 30.4o, were used in the study. Simultaneously with the SAR acquisition, in-situ soil moisture samples over bare agricultural lands were collected and evaluated using gravimetric method. Backscattering coefficients for all polarizations were obtained and linear regression analysis was carried out with in situ moisture measurements. The best correlation coefficient was observed with VV polarization. Cross-polarized backscattering coefficients were not so sensitive to soil moisture content. In the study, it was observed that soil moisture maps can be retrieved with the accuracy about 14% (RMSE.
Directory of Open Access Journals (Sweden)
Ademola A Adeyekun
2013-01-01
Full Text Available Introduction: Fetal weight (FW estimation in late pregnancy is an important guide in obstetric care. Amniotic fluid protects the fetus against traumatic and infective insults. There possibly exists a relationship between FW and amniotic fluid index (AFI that can be estimated by ultrasonography. Materials and Methods: Two hundred and fifty-eight low-risk pregnancies were prospectively studied by means of ultrasound over a 12-month period. FW was estimated using a combination of fetal parameters; bi-parietal diameter, fetal trunk cross sectional area, and femur length. AFI was assessed using the 4-quadrant method. Spearman′s correlation was used to test possible relationship between amniotic fluid indices and estimated FW pairs. The level of statistical significance was set at P ≤ 0.05. Results: The mean AF1 and estimated fetal weight (EFW pairs were as follows: at 27-29 weeks the values were 172.1 mm and 1,250.2 g; at 30-32 weeks AF1 and EFW values were 170.3 mm and 1,648.0 g; at 33-35 weeks values were 162.3 mm and 2,273.5 g; at 36-38 weeks values were 144.09 mm and 2,906.1 g; at 39-40 weeks AF1 and EFW values were 125.0 mm and 3,222.6 g. Overall, there was no statistically significant relationship between AFI and EFW ( P > 0.05; r = 0.241. Conclusion: While FW calculations and amniotic index showed variations in value in late pregnancy, there does not appear to be a linear relationship between ultrasound estimate of FW and amniotic index. The implication of this is that fetal size need not be taken into cognizance when alterations in amniotic fluid values are noted.
Directory of Open Access Journals (Sweden)
Aamir Saghir
2015-12-01
Full Text Available The geometric-Poisson exponentially weighted moving average (EWMA chart has been shown to be more effective than the Poisson EWMA chart in monitoring the number of defects in the production processes. In these applications, it is assumed that the process parameters are known or have been accurately estimated. However, in practice, the process parameters are rarely known and must be estimated from reference sample to construct the geometric-Poisson EWMA chart. The performance of the given chart, due to variability in the parameter estimation, might differ from known parameters’ case. This article explored the effect of estimated parameters on the conditional and marginal performance of the geometric-Poisson EWMA chart. The run length characteristics are calculated using a Markov chain approach and the effect of estimation on the performance of the given chart is shown to be significant. Recommendations about the proposer choice of sample size, smoothing constant, and dispersion parameter are made. Results of this study highlight the practical implications of estimation error, and to offer advice to practitioners when constructing/analyzing a phase-I sample.
Directory of Open Access Journals (Sweden)
Siti Masitoh Kartikawati
2014-04-01
Full Text Available Pasak bumi (Eurycoma longifolia Jack is one of non timber forest products with “indeterminate” conservation status and commercially traded in West Kalimantan. The research objective was to determine the potential of pasak bumi root per hectare and its ecological condition under natural habitat. Root weight of E. longifolia Jack was estimated using simple linear regression and exponential equation with stem diameter and height as independent variables. The results showed that the individual number of the population was 114 with the majority in seedling stage with 71 individuals (62.28%. The distribution was found in clumped pattern. Conditions of the habitat could be described as follows: daily average temperature of 25.6oC, daily average relative humidity of 73.6%, light intensity of 0.9 klx, and red-yellow podsolic soil with texture ranged from clay to sandy clay. The selected estimator model for E. longifolia Jack root weight used exponential equation with stem height as independent variable using the equation of Y= 21.99T0,010 and determination coefficient of 0.97. After height variable was added, the potential of E. longifolia Jack minimum root weight that could be harvested per hectare was 0.33 kg.
Granger causality-based synaptic weights estimation for analyzing neuronal networks.
Shao, Pei-Chiang; Huang, Jian-Jia; Shann, Wei-Chang; Yen, Chen-Tung; Tsai, Meng-Li; Yen, Chien-Chang
2015-06-01
Granger causality (GC) analysis has emerged as a powerful analytical method for estimating the causal relationship among various types of neural activity data. However, two problems remain not very clear and further researches are needed: (1) The GC measure is designed to be nonnegative in its original form, lacking of the trait for differentiating the effects of excitations and inhibitions between neurons. (2) How is the estimated causality related to the underlying synaptic weights? Based on the GC, we propose a computational algorithm under a best linear predictor assumption for analyzing neuronal networks by estimating the synaptic weights among them. Under this assumption, the GC analysis can be extended to measure both excitatory and inhibitory effects between neurons. The method was examined by three sorts of simulated networks: those with linear, almost linear, and nonlinear network structures. The method was also illustrated to analyze real spike train data from the anterior cingulate cortex (ACC) and the striatum (STR). The results showed, under the quinpirole administration, the significant existence of excitatory effects inside the ACC, excitatory effects from the ACC to the STR, and inhibitory effects inside the STR.
Random weighting error estimation for the inversion result of finite-fault rupture history
Ai, Yin-Shuang; Zheng, Tian-Yu; He, Yu-Mei
1999-07-01
Since the non-unique solution exists in the inversion for finite-fault rupture history, the random weighting method has been used to estimate error of the inversion results in this paper. The resolution distributions of slip amplitude, rake, rupture time and rise time on the finite fault were deduced quantitatively by model calculation. By using the random weighting method, the inversion results of Taiwan Strait earthquake and Myanmar-China boundary earthquake show that the parameters related to the rupture centers of two events have the highest resolution, and the solution are the most reliable; otherwise the resolution of the slip amplitudes and rise time on the finite-fault boundary is low.
Fuel Consumption Reduction and Weight Estimate of an Intercooled-Recuperated Turboprop Engine
Andriani, Roberto; Ghezzi, Umberto; Ingenito, Antonella; Gamma, Fausto
2012-09-01
The introduction of intercooling and regeneration in a gas turbine engine can lead to performance improvement and fuel consumption reduction. Moreover, as first consequence of the saved fuel, also the pollutant emission can be greatly reduced. Turboprop seems to be the most suitable gas turbine engine to be equipped with intercooler and heat recuperator thanks to the relatively small mass flow rate and the small propulsion power fraction due to the exhaust nozzle. However, the extra weight and drag due to the heat exchangers must be carefully considered. An intercooled-recuperated turboprop engine is studied by means of a thermodynamic numeric code that, computing the thermal cycle, simulates the engine behavior at different operating conditions. The main aero engine performances, as specific power and specific fuel consumption, are then evaluated from the cycle analysis. The saved fuel, the pollution reduction, and the engine weight are then estimated for an example case.
FN-curves: preliminary estimation of severe accident risks after Fukushima
Energy Technology Data Exchange (ETDEWEB)
Vasconcelos, Vanderley de; Soares, Wellington Antonio; Costa, Antonio Carlos Lopes da, E-mail: vasconv@cdtn.br, E-mail: soaresw@cdtn.br, E-mail: aclc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)
2015-07-01
Doubts of whether the risks related to severe accidents in nuclear reactors are indeed very low were raised after the nuclear accident at Fukushima Daiichi in 2011. Risk estimations of severe accidents in nuclear power plants involve both probability and consequence assessment of such events. Among the ways to display risks, risk curves are tools that express the frequency of exceeding a certain magnitude of consequence. Societal risk is often represented graphically in a FN-curve, a type of risk curve, which displays the probability of having N or more fatalities per year, as a function of N, on a double logarithmic scale. The FN-curve, originally introduced for the assessment of the risks in the nuclear industry through the U.S.NRC Reactor Safety Study WASH-1400 (1975), is used in various countries to express and limit risks of hazardous activities. This first study estimated an expected rate of core damage equal to 5x10{sup -5} by reactor-year and suggested an upper bound of 3x10{sup -4} by reactor-year. A more recent report issued by Electric Power Research Institute - EPRI (2008) estimates a figure of the order of 2x10{sup -5} by reactor-year. The Fukushima nuclear accident apparently implies that the observed core damage frequency is higher than that predicted by these probabilistic safety assessments. Therefore, this paper presents a preliminary analyses of the FN-curves related to severe nuclear reactor accidents, taking into account a combination of available data of past accidents, probability modelling to estimate frequencies, and expert judgments. (author)
Widyaningsih, Purnami; Retno Sari Saputro, Dewi; Nugrahani Putri, Aulia
2017-06-01
GWOLR model combines geographically weighted regression (GWR) and (ordinal logistic reression) OLR models. Its parameter estimation employs maximum likelihood estimation. Such parameter estimation, however, yields difficult-to-solve system of nonlinear equations, and therefore numerical approximation approach is required. The iterative approximation approach, in general, uses Newton-Raphson (NR) method. The NR method has a disadvantage—its Hessian matrix is always the second derivatives of each iteration so it does not always produce converging results. With regard to this matter, NR model is modified by substituting its Hessian matrix into Fisher information matrix, which is termed Fisher scoring (FS). The present research seeks to determine GWOLR model parameter estimation using Fisher scoring method and apply the estimation on data of the level of vulnerability to Dengue Hemorrhagic Fever (DHF) in Semarang. The research concludes that health facilities give the greatest contribution to the probability of the number of DHF sufferers in both villages. Based on the number of the sufferers, IR category of DHF in both villages can be determined.
Bedside method to estimate actual body weight in the Emergency Department.
Buckley, Robert G; Stehman, Christine R; Dos Santos, Frank L; Riffenburgh, Robert H; Swenson, Aaron; Mjos, Nathan; Brewer, Matt; Mulligan, Sheila
2012-01-01
Actual body weight (ABW) is important for accurate drug dosing in emergency settings. Oftentimes, patients are unable to stand to be weighed accurately or clearly state their most recent weight. Develop a bedside method to estimate ABW using simple anthropometric measurements. Prospective, blinded, cross-sectional convenience sampling of adult Emergency Department (ED) patients. A multiple linear regression equation from Derivation Phase (n = 208: 121 males, 87 females) found abdominal and thigh circumferences (AC and TC) had the best fit and an inter-rater correlation of 0.99 and 0.96, respectively: Male ABW (kg) = -47.8 + 0.78 ∗ (AC) + 1.06 ∗ (TC); Female ABW = -40.2 + 0.47 ∗ (AC) + 1.30 ∗ (TC). Derivation phase: Number of patients (%) with a body weight estimation (BWE) > 10 kg from ABW for males/females were: 7 (6%)/1 (1%) for Patients, 46 (38%)/28 (32%) for Doctors, 38 (31%)/24 (27%) for Nurses, 75 (62%)/43 (49%) for 70 kg/60 kg convention, and 14 (12%)/8 (9%) using the anthropometric regression model. For validation phase (55 males, 44 females): Gold standard ABW mean (SD) male/female = 83.6 kg (14.3)/71.5 kg (18.9) vs. anthropometric regression model = 86.3 kg (14.7)/73.3 kg (15.1). R(2) = 0.89, p 10 kg using the anthropometric regression model = 8 (15%)/11 (27%). For male patients, a regression model using supine thigh and abdominal circumference measurements seems to provide a useful and more accurate alternative to physician, nurse, or standard 70-kg male conventional estimates, but was less accurate for use in female patients. Published by Elsevier Inc.
Estimation of Body Weight from Body Size Measurements and Body Condition Scores in Dairy Cows
DEFF Research Database (Denmark)
Enevoldsen, Carsten; Kristensen, T.
1997-01-01
regimen. Results from this study indicate that a reliable model for estimating BW of very different dairy cows maintained in a wide range of environments can be developed using body condition score, demographic information, and measurements of hip height and hip width. However, for management purposes......The objective of this study was to evaluate the use of hip height and width, body condition score, and relevant demographic information to predict body weight (BW) of dairy cows. Seven regression models were developed from data from 972 observations of 554 cows. Parity, hip height, hip width......, substantial improvements can be obtained by developing models that are specific to a given site....
Avatar Weight Estimates based on Footstep Sounds in Three Presentation Formats
DEFF Research Database (Denmark)
Sikström, Erik; Götzen, Amalia De; Serafin, Stefania
2015-01-01
When evaluating a sound design for virtual environment, the context where it is to be implemented in may have an influence on how it may be perceived. In this paper we perform an experiment comparing three presentation formats (audio only, video with audio and an interactive immersive VR format......) and their influences on a sound design evaluation task concerning footstep sounds. The evaluation involved estimating the perceived weight of a virtual avatar seen from a first person perspective, as well as the suitability of the sound effect relative to the context. The results show significant differences for three...
Zea, Sven
1992-09-01
During a study of the spatial and temporal patterns of desmosponge (Porifera, Demospongiae) recruitment on rocky and coral reef habitats of Santa Marta, Colombian Caribbean Sea, preliminary attempts were made to estimate actual settlement rates from short-term (1 to a few days) recruitment censuses. Short-term recruitment rates on black, acrylic plastic plates attached to open, non-cryptic substratum by anchor screws were low and variable (0 5 recruits/plate in 1 2 days, sets of n=5 10 plates), but reflected the depth and seasonal trends found using mid-term (1 to a few months) censusing intervals. Moreover, mortality of recruits during 1 2 day intervals was low (0 12%). Thus, short-term censusing intervals can be used to estimate actual settlement rates. To be able to make statistical comparisons, however, it is necessary to increase the number of recruits per census by pooling data of n plates per set, and to have more than one set per site or treatment.
Energy Technology Data Exchange (ETDEWEB)
Uhl, Markus; Saueressig, Ulrich; Bley, Thorsten; Langer, Mathias [University Hospital, Department of Radiology, Freiburg (Germany); Koehler, Gabriele [University Hospital, Department of Pathology, Freiburg (Germany); Kontny, Udo [University Hospital, Children' s Hospital, Freiburg (Germany); Niemeyer, Charlotte [University Hospital, Department of Paediatric Oncology, Freiburg (Germany); Reichardt, Wilfried; Ilyasof, Kamil [University Hospital, Department of Medical Physics, Freiburg (Germany)
2006-12-15
During successful chemotherapy of osteosarcomas tumour size does not diminish significantly because the therapy has limited impact on the mineralized matrix of the tumour. Treatment response is considered successful if, histologically, more than 90% of tumour cells show necrosis. To determine if osteosarcomas change their water diffusion during preoperative chemotherapy in relation to the amount of tumour necrosis. Eight patients (age 11-19 years) with histologically proven limb osteosarcoma underwent T1-weighted, fat-suppressed T2-weighted and contrast-enhanced T1-weighted spin-echo imaging together with diffusion-weighted EPI sequences (b = 700) at 1.5 T before and after five cycles of standard chemotherapy. Tumour volume and apparent diffusion coefficient (ADC) maps were calculated before and after chemotherapy. The degree of tumour necrosis after chemotherapy was assessed using the histological Salzer-Kuntschik classification (grades 1-6). During chemotherapy, the ADC values of osteosarcomas changed significantly. The ADC of untreated tumour was 2.1 {+-} 0.4 x 10{sup -3} mm{sup 2}/s (mean {+-} SD) (95% CI 1.6-2.0). The ADC of chemotherapy-treated sarcomas was 2.5 {+-} 0.4 x 10{sup -3} mm{sup 2}/s (95% CI 1.8-2.2). Necrotic areas, which were confirmed by macroscopic examination, showed ADC values up to 2.7 x 10{sup -3} mm{sup 2}/s. Four patients with little viable tumour tissue within the neoplasm (Salzer-Kuntschik grades 1-2) had an increase in ADC of 0.4 up to 0.7 x 10{sup -3} mm{sup 2}/s. Four patients with larger areas of viable tumour (Salzer-Kuntschik grade 4) showed a lesser increase in ADC of 0.0 up to 0.3 x 10{sup -3} mm{sup 2}/s. The differences in ADC values in tumour tissue before and after chemotherapy were highly significant (P = 0.01). During chemotherapy of osteosarcomas, tumour ADC changes are related to the degree of tumour necrosis. (orig.)
Lu, Dan; Ye, Ming; Meyer, Philip D.; Curtis, Gary P.; Shi, Xiaoqing; Niu, Xu-Feng; Yabusaki, Steve B.
2013-01-01
When conducting model averaging for assessing groundwater conceptual model uncertainty, the averaging weights are often evaluated using model selection criteria such as AIC, AICc, BIC, and KIC (Akaike Information Criterion, Corrected Akaike Information Criterion, Bayesian Information Criterion, and Kashyap Information Criterion, respectively). However, this method often leads to an unrealistic situation in which the best model receives overwhelmingly large averaging weight (close to 100%), which cannot be justified by available data and knowledge. It was found in this study that this problem was caused by using the covariance matrix, CE, of measurement errors for estimating the negative log likelihood function common to all the model selection criteria. This problem can be resolved by using the covariance matrix, Cek, of total errors (including model errors and measurement errors) to account for the correlation between the total errors. An iterative two-stage method was developed in the context of maximum likelihood inverse modeling to iteratively infer the unknown Cek from the residuals during model calibration. The inferred Cek was then used in the evaluation of model selection criteria and model averaging weights. While this method was limited to serial data using time series techniques in this study, it can be extended to spatial data using geostatistical techniques. The method was first evaluated in a synthetic study and then applied to an experimental study, in which alternative surface complexation models were developed to simulate column experiments of uranium reactive transport. It was found that the total errors of the alternative models were temporally correlated due to the model errors. The iterative two-stage method using Cekresolved the problem that the best model receives 100% model averaging weight, and the resulting model averaging weights were supported by the calibration results and physical understanding of the alternative models. Using Cek
Energy Technology Data Exchange (ETDEWEB)
Lu, Dan; Ye, Ming; Meyer, Philip D.; Curtis, Gary P.; Shi, Xiaoqing; Niu, Xu-Feng; Yabusaki, Steven B.
2013-07-23
When conducting model averaging for assessing groundwater conceptual model uncertainty, the averaging weights are often evaluated using model selection criteria such as AIC, AICc, BIC, and KIC (Akaike Information Criterion, Corrected Akaike Information Criterion, Bayesian Information Criterion, and Kashyap Information Criterion, respectively). However, this method often leads to an unrealistic situation in which the best model receives overwhelmingly large averaging weight (close to 100%), which cannot be justified by available data and knowledge. It was found in this study that this problem was caused by using the covariance matrix, CE, of measurement errors for estimating the negative log likelihood function common to all the model selection criteria. This problem can be resolved by using the covariance matrix, Cek, of total errors (including model errors and measurement errors) to account for the correlation between the total errors. An iterative two-stage method was developed in the context of maximum likelihood inverse modeling to iteratively infer the unknown Cek from the residuals during model calibration. The inferred Cek was then used in the evaluation of model selection criteria and model averaging weights. While this method was limited to serial data using time series techniques in this study, it can be extended to spatial data using geostatistical techniques. The method was first evaluated in a synthetic study and then applied to an experimental study, in which alternative surface complexation models were developed to simulate column experiments of uranium reactive transport. It was found that the total errors of the alternative models were temporally correlated due to the model errors. The iterative two-stage method using Cek resolved the problem that the best model receives 100% model averaging weight, and the resulting model averaging weights were supported by the calibration results and physical understanding of the alternative models. Using Cek
Lu, Dan; Ye, Ming; Meyer, Philip D.; Curtis, Gary P.; Shi, Xiaoqing; Niu, Xu-Feng; Yabusaki, Steve B.
2013-09-01
When conducting model averaging for assessing groundwater conceptual model uncertainty, the averaging weights are often evaluated using model selection criteria such as AIC, AICc, BIC, and KIC (Akaike Information Criterion, Corrected Akaike Information Criterion, Bayesian Information Criterion, and Kashyap Information Criterion, respectively). However, this method often leads to an unrealistic situation in which the best model receives overwhelmingly large averaging weight (close to 100%), which cannot be justified by available data and knowledge. It was found in this study that this problem was caused by using the covariance matrix, Cɛ, of measurement errors for estimating the negative log likelihood function common to all the model selection criteria. This problem can be resolved by using the covariance matrix, Cek, of total errors (including model errors and measurement errors) to account for the correlation between the total errors. An iterative two-stage method was developed in the context of maximum likelihood inverse modeling to iteratively infer the unknown Cek from the residuals during model calibration. The inferred Cek was then used in the evaluation of model selection criteria and model averaging weights. While this method was limited to serial data using time series techniques in this study, it can be extended to spatial data using geostatistical techniques. The method was first evaluated in a synthetic study and then applied to an experimental study, in which alternative surface complexation models were developed to simulate column experiments of uranium reactive transport. It was found that the total errors of the alternative models were temporally correlated due to the model errors. The iterative two-stage method using Cek resolved the problem that the best model receives 100% model averaging weight, and the resulting model averaging weights were supported by the calibration results and physical understanding of the alternative models. Using Cek
Institute of Scientific and Technical Information of China (English)
KUK Anthony
2009-01-01
@@ The survival analysis literature has always lagged behind the categorical data literature in developing methods to analyze clustered or multivariate data. While estimators based on working correlation matrices, optimal weighting, composite likelihood and various variants have been proposed in the categorical data literature, the working independence estimator is still very much the prevalent estimator in multivariate survival data analysis.
On the least-square estimation of parameters for statistical diffusion weighted imaging model.
Yuan, Jing; Zhang, Qinwei
2013-01-01
Statistical model for diffusion-weighted imaging (DWI) has been proposed for better tissue characterization by introducing a distribution function for apparent diffusion coefficients (ADC) to account for the restrictions and hindrances to water diffusion in biological tissues. This paper studies the precision and uncertainty in the estimation of parameters for statistical DWI model with Gaussian distribution, i.e. the position of distribution maxima (Dm) and the distribution width (σ), by using non-linear least-square (NLLS) fitting. Numerical simulation shows that precise parameter estimation, particularly for σ, imposes critical requirements on the extremely high signal-to-noise ratio (SNR) of DWI signal when NLLS fitting is used. Unfortunately, such extremely high SNR may be difficult to achieve for the normal setting of clinical DWI scan. For Dm and σ parameter mapping of in vivo human brain, multiple local minima are found and result in large uncertainties in the estimation of distribution width σ. The estimation error by using NLLS fitting originates primarily from the insensitivity of DWI signal intensity to distribution width σ, as given in the function form of the Gaussian-type statistical DWI model.
PRELIMINARY APPLICATION OF WHOLE BODY DIFFUSION WEIGHTED IMAGING IN SCREENING METASTASIS
Institute of Scientific and Technical Information of China (English)
Yong-jing Guan; Hua-wei Ling; Ke-min Chen
2008-01-01
Objective To investigate the feasibility of whole body diffusion weighted imaging (WB-DWI) in screening metastasis.Methods WB-DWI was performed in 24 patients diagnosed with various types of primary tumors. The three-dimensional maximum intensity projection reconstruction and black-and-white flip technique were used to observe metastatic lesions, and the results were compared with those of bone scintigraphy. Results By WB-DWI scanning sequence at b = 800 s/mm2, all the bone lesions found by bone scintigraphy in the cohort were well identified, and other lesions of soft tissue and organs were also well demonstrated. Its screening capability was equivalent with bone scintigraphy in screening metastases in bones (P = 0.062). Conclusion WB-DWI was practicable with the parameter settings attempted in metastases screening.
Change in diffusion weighted MRI during liver cancer radiotherapy: Preliminary observations
Energy Technology Data Exchange (ETDEWEB)
Eccles, Cynthia L.; Haider, Ehsan A.; Haider, Masoom A.; Fung, Sharon; Lockwood, Gina; Dawson, Laura A. (University of Toronto, Toronto, Ontario (Canada))
2009-10-15
Purpose. To evaluate diffusion weighted magnetic resonance imaging (DWI) in liver and liver cancers during and following conformal radiotherapy (RT). To determine the feasibility of using changes in apparent diffusion coefficients (ADC) as a potential surrogate for tumour control or normal tissue injury. Materials and methods. Patients on a six-fraction conformal liver RT protocol underwent DW-MRI at the time of treatment planning, during RT (week one and two) and one month following RT. Diffusion weighted MR images were acquired in exhale breath hold, using b-values of 0 and 600. Regions of interest (ROIs) corresponding to maximal tumour dose, high-dose peri-tumour liver, irradiated normal liver, non-irradiated liver, and spleen were analyzed on ADC maps. Results. Eleven patients (four hepatocellular carcinoma, five liver metastases, two cholangiocarcinoma) were evaluated. The baseline median tumour ADC of 1.56x10-3mm2/sec increased to 1.89x10-3mm2/sec at RT week one, to 1.91x10-3mm2/sec during week two and to 2.01x10-3mm2/sec at one month following treatment (p < 0.0001). Early increases in mean ADC were correlated with higher dose and sustained tumour response, whereas RECIST and volume changes on T2 images were not. Peri-tumour mean ADC also increased, from 1.40x10-3mm2/sec (baseline) to 1.55x10-3mm2/sec (RT week 2) and 1.64 x 10-3mm2/sec (follow-up). Small ADC changes were seen in the irradiated liver, and no significant changes were seen in the un-irradiated liver. Conclusions. Changes in tumour ADC were seen during RT. Larger increases were correlated with higher doses and increased likelihood of response
Effect of large weight reductions on measured and estimated kidney function
DEFF Research Database (Denmark)
von Scholten, Bernt Johan; Persson, Frederik; Svane, Maria S
2017-01-01
BACKGROUND: When patients experience large weight loss, muscle mass may be affected followed by changes in plasma creatinine (pCr). The MDRD and CKD-EPI equations for estimated GFR (eGFR) include pCr. We hypothesised that a large weight loss reduces muscle mass and pCr causing increase in e......GFR was assessed during four hours plasma (51)Cr-EDTA clearance. GFR was estimated by four equations (MDRD, CKD-EPI-pCr, CKD-EPI-cysC and CKD-EPI-pCr-cysC). DXA-scans were performed at baseline and six months post-surgery to measure changes in lean limb mass, as a surrogate for muscle mass. RESULTS: Patients were....../min (p = 0.024), but corrected for current body surface area (BSA) mGFR was unchanged by 2 (-5; 9) ml/min/1.73 m(2) (p = 0.52). CKD-EPI-pCr increased by 12 (6; 17) and MDRD by 13 (8; 18) (p CKD-EPI-cysC was unchanged by 2 (-8; 4) ml/min/1.73 m(2) (p = 0.51). Lean limb mass...
Geerts, Lut; Widmer, Tania
2011-02-01
To identify the most accurate formula to estimate fetal weight (EFW) from ultrasound parameters in severe preterm preeclampsia. In a prospective study, serial ultrasound assessments were performed in 123 women with severe preterm preeclampsia. The EFW, calculated for 111 live born, normal, singleton fetuses within 7 days of delivery using 38 published formulae, was compared to the actual birth weight (ABW). Accuracy was assessed by correlations, mean (absolute and signed) (%) errors, % correct predictions within 5-20% of ABW and limits of agreement. Accuracy was highly variable. Most formulae systematically overestimated ABW. Five Hadlock formulae utilizing three or four variables and Woo 3 formula had the highest accuracy and did not differ significantly (mean absolute % errors 6.8-7.2%, SDs 5.3-5.8%, > 75% of estimations within 10% of ABW and 95% limits of agreement between -18/20% and +14/15%). They were not negatively affected by clinical variables but had some inconsistency in bias over the ABW range. All other formulae, including those targeted for small, preterm or growth restricted fetuses, were inferior and/or affected by multiple clinical variables. In this GA window, Hadlock formulae using three or four variables or Woo 3 formula can be recommended.
A clinical study of association of maternal height and estimated foetal weight on mode of delivery
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Anup Ramrao Patil
2015-08-01
Methods: 240 full term primigravida women without any obstetric and medical complications who were admitted in Acharya Vinoba Bhave Rural Hospital Wardha for delivery were randomly selected for study. After delivery 138 women who underwent caesarean delivery formed the study group and 102 women who underwent vaginal delivery formed control group. These two groups were compared for their maternal heights and antenatal estimated foetal weight (by Johnson's formula. Results: In present study (1 Mean height of women in study group was 147 cm while that in control group was 155 cm. (2 Out of 49 short statured women (height and #8804; 145 cm 47 (95.91% had emergency caesarean section and 2(4.08% women were delivered vaginally. (3 Estimated foetal weight in study group was 2956 grams while that in control group was 2845 grams. Conclusions: We conclude that short statured women with larger baby size has higher incidence of emergency caesarean delivery. [Int J Reprod Contracept Obstet Gynecol 2015; 4(4.000: 1020-1024
Miyamoto, Kayoko; Nishimuta, Mamoru; Hamaoka, Takafumi; Kodama, Naoko; Yoshitake, Yutaka
2012-01-01
To determine the energy intake (EI) required to maintain body weight (equilibrium energy intake: EEI), we investigated the relationship between calculated energy intake and body weight changes in female subjects participating in 14 human balance studies (n=149) conducted at the National Institute of Health and Nutrition (Tokyo). In four and a half studies (n=43), sweat was collected from the arm to estimate loss of minerals through sweating during exercise on a bicycle ergometer; these subjects were classified in the exercise group (Ex G). In nine and a half experiments (n=106) subjects did not exercise, and were classified in the sedentary group (Sed G). The relationship between dietary energy intake (EI) and body weight (BW) changes (ΔBW) was analyzed and divided by four variables: body weight (BW), lean body mass (LBM), standard body weight (SBW), and body surface area (BSA). Equilibrium energy intake (EEI) and 95% confidence interval (CI) for EEI in Ex G were 34.3 and 32.8-35.9 kcal/kg BW/d, 32.0 and 30.8-33.1 kcal/kg SBW/d, 46.3 and 44.2-48.5 kcal/kg LBW/d, and 1,200 and 1,170-1,240 kcal/m(2) BSA/d, respectively. EEI and 95% CI for EEI in Sed G were 34.5 and 33.9-35.1 kcal/kg BW/d, 31.4 and 30.9-32.0 kcal/kg SBW/d, 44.9 and 44.1-45.8 kcal/kg LBM/d, and 1,200 and 1,180-1,210 kcal/m2 BSA/d, respectively. EEIs obtained in this study are 3 to 5% higher than estimated energy requirement (EER) for Japanese. In five out of six analyses, EER in a population (female, 18-29 y, physical activity level: 1.50) was under 95% CI of EEI obtained in this study.
LENUS (Irish Health Repository)
Bushe, Chris J
2008-01-01
BACKGROUND: Weight gain is commonly observed during psychotropic treatments for chronic forms of severe mental illness and is most rapid during the early treatment phases. All formats of behavioural weight intervention programmes have suggested that weight gain can be prevented or reversed in some patients. There is no data on these programmes in acutely unwell inpatients whom may be the major beneficiaries. METHODS: A modular behavioural intervention programme (Solutions for Wellness) used in SMI outpatients since 2002 in Ireland has been adapted for inpatient use. Preliminary data is reported from 5 centres in Ireland. RESULTS: In 47 inpatients the mean weight change was +0.26 kg (SD 2.02) with a median change of 0 kg. Mean follow-up was 23.7 (SD 21.6) days, and median 14 days (range 6-98 days). There was no difference in mean weight change in those patients involved for > 35 days compared with < 35 days (+0.26 kg; 0.25 kg; p = 0.5). Weight loss or maintenance was seen in 70% of patients. CONCLUSION: These preliminary data are supportive of the concept that acutely unwell inpatients with SMI may engage with a behavioural weight programme. Weight change observed contrasts with the significant weight gain often seen in most subjects. Further clinical trials are warranted.
Optical Performance and Weight Estimation of a Heliostat with Ganged Facets
Energy Technology Data Exchange (ETDEWEB)
Amsbeck, L.; Buck, R.; Pfahl, A.; Uhlig, R.
2006-07-01
In standard heliostat design the usual strategy of cost reduction is to increase the mirror area of the heliostats. This leads to a reduction of specific drive cost, but also to an increase of the torques caused by the wind loads, resulting in higher specific weight and higher specific drive power. The opposite strategy focuses on the reduction of the specific weight and driving power. Therefore the mirror area is decreased. In total the drive power is much lower then, but it has to be divided into more units which means a drawback for cost reduction. A combination of both strategies is to couple small heliostats so that they can be tracked by the same drive. At the Torque Tube Heliostat (TTH) the mirrors are mounted on torque tubes to simplify the coupling mechanism for the elevation angle. The optimal tracking speed of heliostats depends on the position in the field. In a heliostat with ganged facets all facets are tracked with the same speed. This leads to higher astigmatism losses compared to independently tracked mirrors. To reduce shading a certain space is foreseen between the facets of the TTH. To achieve a high mirror density and to avoid too long and therefore too flexible torque tubes this distance is limited. Thus the shading is higher than usually. Ray tracing calculations were done to obtain optimized heliostat configurations and to estimate the energy yield of a heliostat field built of 288 square meters TTHs. The results are compared to a conventional heliostat field. To get an idea of the weight reduction potential of the TTH the dimensions of the torque tube, the secondary axis tube and the mirror support structure were weight optimized via FEM. The layout criterion was a mean mirror error of 5 mrad under a wind load and gravity, which was calculated from the deviations of the FE model. (Author)
Development and validation of GFR-estimating equations using diabetes, transplant and weight
Stevens, Lesley A.; Schmid, Christopher H.; Zhang, Yaping L.; Coresh, Josef; Manzi, Jane; Landis, Richard; Bakoush, Omran; Contreras, Gabriel; Genuth, Saul; Klintmalm, Goran B.; Poggio, Emilio; Rossing, Peter; Rule, Andrew D.; Weir, Matthew R.; Kusek, John; Greene, Tom; Levey, Andrew S.
2010-01-01
Background. We have reported a new equation (CKD-EPI equation) that reduces bias and improves accuracy for GFR estimation compared to the MDRD study equation while using the same four basic predictor variables: creatinine, age, sex and race. Here, we describe the development and validation of this equation as well as other equations that incorporate diabetes, transplant and weight as additional predictor variables. Methods. Linear regression was used to relate log-measured GFR (mGFR) to sex, race, diabetes, transplant, weight, various transformations of creatinine and age with and without interactions. Equations were developed in a pooled database of 10 studies [2/3 (N = 5504) for development and 1/3 (N = 2750) for internal validation], and final model selection occurred in 16 additional studies [external validation (N = 3896)]. Results. The mean mGFR was 68, 67 and 68 ml/min/ 1.73 m2 in the development, internal validation and external validation datasets, respectively. In external validation, an equation that included a linear age term and spline terms in creatinine to account for a reduction in the magnitude of the slope at low serum creatinine values exhibited the best performance (bias = 2.5, RMSE = 0.250) among models using the four basic predictor variables. Addition of terms for diabetes and transplant did not improve performance. Equations with weight showed a small improvement in the subgroup with BMI <20 kg/m2. Conclusions. The CKD-EPI equation, based on creatinine, age, sex and race, has been validated and is more accurate than the MDRD study equation. The addition of weight, diabetes and transplant does not significantly improve equation performance. PMID:19793928
A Novel Approach to Speaker Weight Estimation Using a Fusion of the i-vector and NFA Frameworks
DEFF Research Database (Denmark)
Poorjam, Amir Hossein; Bahari, Mohamad Hasan; Van hamme, Hogo
2017-01-01
This paper proposes a novel approach for automatic speaker weight estimation from spontaneous telephone speech signals. In this method, each utterance is modeled using the i-vector framework which is based on the factor analysis on Gaussian Mixture Model (GMM) mean supervectors, and the Non......-negative Factor Analysis (NFA) framework which is based on a constrained factor analysis on GMM weight supervectors. Then, the available information in both Gaussian means and Gaussian weights is exploited through a feature-level fusion of the i-vectors and the NFA vectors. Finally, a least-squares support vector...... of the proposed approach, this method is compared to the i-vector-based speaker weight estimation and an alternative fusion scheme, namely the score-level fusion. Experimental results over 2339 utterances show that the correlation coefficients between the actual and the estimated weights of female and male...
Institute of Scientific and Technical Information of China (English)
Tian-he Yang; Jian-zhong Lin; Xin Wang; Jian-hua Lu; Zhong Chen
2008-01-01
Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in the diagnosis of metastatic tumor.Methods Fifty-six patients (40 males and 16 females, age ranging from 29 to 84 years with a mean age of 57 years) with a variety of primary tumors were investigated by whole body DWI combined with computed tomography (CT) and/or conventional magnetic resonance imaging (MRI) scans. Twelve patients underwent positron emission tomography. The final diagnosis was made on the basis of CT or high resolution CT result for lung lesion and MRI or CT result for skull, abdomen and other parts. All tumors were classified into four groups by their diameter: below 1.0 cm, 1.0-1.9 cm, 2.0-2.9 cm, and above 3.0 cm. The sensitivity and specificity of whole body DWI in the detection of metastatic tumor were analyzed.Results The sensitivities of whole body DWI for screening metastasis oftlie four groups were 38%, 75%, 97%, and 100%, respectively. Whole body DWI showed the highest sensitivity and specificity for detecting metastasis of the skeletal system. It was difficult to find metastatic tumor whose diameter was below 1.0 cm, or lymph nodes located in the pelvis with diameter below 2.0 cm. Conclusions Whole body DWI is a promising method in the diagnosis ofmetastastic tumors. With the perfection of scanning parameter, whole body DWI should be a new effective whole body technique for tumor detection.
Olesen, Jacob Bjerring; Villagomez-Hoyos, Carlos Armando; Traberg, Marie Sand; Chee, Adrian J. Y.; Yiu, Billy Y. S.; Ho, Chung Kit; Yu, Alfred C. H.; Jensen, Jørgen Arendt
2016-04-01
This paper presents a method for measuring pressure changes in deep-tissue vessels using vector velocity ultrasound data. The large penetration depth is ensured by acquiring data using a low frequency phased array transducer. Vascular pressure changes are then calculated from 2-D angle-independent vector velocity fields using a model based on the Navier-Stokes equations. Experimental scans are performed on a fabricated flow phantom having a constriction of 36% at a depth of 100 mm. Scans are carried out using a phased array transducer connected to the experimental scanner, SARUS. 2-D fields of angle-independent vector velocities are acquired using directional synthetic aperture vector flow imaging. The obtained results are evaluated by comparison to a 3-D numerical simulation model with equivalent geometry as the designed phantom. The study showed pressure drops across the constricted phantom varying from -40 Pa to 15 Pa with a standard deviation of 32%, and a bias of 25% found relative to the peak simulated pressure drop. This preliminary study shows that pressure can be estimated non-invasively to a depth that enables cardiac scans, and thereby, the possibility of detecting the pressure drops across the mitral valve.
Hu, Jing; Hu, Jie; Wang, Yuanmei
2003-03-01
In magnetoencepholography(MEG) inverse research, according to the point source model and distributed source model, the neuromagnetic source reconstruction methods are classified as parametric current dipole localization and nonparametric source imaging (or current density reconstruction). MEG source imaging technique can be formulated as an inherent ill-posed and highly underdetermined linear inverse problem. In order to yield a robust and plausible neural current distribution image, various approaches have been proposed. Among those, the weighted minimum-norm estimation with Tikhonov regularization is a popular technique. The authors present a relatively overall theoretical framework Followed by a discussion of the development, several regularized minimum-norm algorithms have been described in detail, including the depth normalization, low resolution electromagnetic tomography(LORETA), focal underdetermined system solver(FOCUSS), selective minimum-norm(SMN). In addition, some other imaging methods, e.g., maximum entropy method(MEM), the method incorporating other brain functional information such as fMRI data and maximum a posteriori(MAP) method using Markov random field model, are explained as well. From the generalized point of view based on minimum-norm estimation with Tikhonov regularization, all these algorithms are aiming to resolve the tradeoff between fidelity to the measured data and the constraints assumptions about the neural source configuration such as anatomical and physiological information. In conclusion, almost all the source imaging approaches can be consistent with the regularized minimum-norm estimation to some extent.
Energy Technology Data Exchange (ETDEWEB)
Li, Qinghai; Li, Jinning; Zhang, Lan; Chen, Ying; Zhang, Minming [Department of Radiology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009 (China); Yan, Fuhua, E-mail: zemylife@163.com [Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025 (China)
2014-05-15
Objective: To investigate the clinical potential of diffusion-weighted imaging (DWI) in assessing renal pathology of chronic kidney disease (CKD). Methods: Seventy-one CKD patients and twelve healthy volunteers were examined using DWI with prospective acquisition correction. Renal biopsy specimens from the CKD patients were scored based on the severity of renal pathology and to confirm pathology type. CKD patients were divided into three groups according to pathology scores: mild, moderate, or severe. The association between renal apparent diffusion coefficient (ADC) values and pathology scores was investigated using Pearson's correlation and single factor analysis of variance. Multiple linear regression analysis was performed to explore associations between renal ADC values and pathology score, glomerular filtration rate, serum creatinine, and age. The Kruskal–Wallis H test was conducted to compare ADC values and pathology type. Results: Renal ADC values correlated negatively with pathology scores (r = −0.633, P < 0.001). The ADC values among the four groups (mild, moderate, severe impairment, and controls) were significantly different (F = 19.512, P < 0.001). However, when patients were stratified by pathology type, no significant differences were found in ADC values among these groups (χ{sup 2} = 9.929, P = 0.270). Further multiple linear regression analysis showed that only the pathology score and ADC values were related (t = −4.586, P = 0.000). Conclusions: DWI has clinical potential in assessing the severity of renal pathology in CKD and shows promise as a non-invasive and effective technique to guide therapy and follow-up.
Diffusion-weighted Magnetic Resonance Imaging in the Diagnosis of Bone Tumors: Preliminary Results
Directory of Open Access Journals (Sweden)
Yeliz Pekcevik
2013-01-01
Full Text Available Objective: The study aims to determine whether apparent diffusion coefficient (ADC can help differentiate benign and malignant bone tumors. Materials and Methods: From January 2012 to February 2013, we prospectively included 26 patients. Of these 15 patients were male and 11 were female; ranging in age from 8 to 76 years (mean age, 34.5 years. Diffusion-weighted magnetic resonance (MR imaging was obtained with a single-shot echo-planar imaging sequence using a 1.5T MR scanner. We grouped malignant lesions as primary, secondary, and primary tumor with chondroid matrix. The minimum ADC was measured in the tumors and mean minimum ADC values were selected for statistical analysis. ADC values were compared between malignant and benign tumors using the Mann-Whitney U-test and receiver operating curve analysis were done to determine optimal cut-off values. Results: The mean ADC values from the area with lowest ADC values of benign and malignant tumors were 1.99 ± 0.57 × 10−3 mm 2 /s and 1.02 ± 1.0 × 10−3 mm 2 /s, respectively. The mean minimum ADC values of benign and malignant tumors were statistically different (P = 0.029. With cut-off value of 1.37 (10−3 mm 2 /s, sensitivity was 77.8% and specificity was 82.4%, for distinguishing benign and malignant lesion. Benign and secondary malignant tumors showed statistically significant difference (P = 0.002. There was some overlap in ADC values between benign and malignant tumors. The mean minimum ADC values of benign and malignant chondroid tumors were high. Giant cell tumor, non-ossifying fibroma and fibrous dysplasia showed lower ADC values. Conclusion: Although there is some overlap, ADC values of benign and malignant bone tumors seem to be different. Further studies with larger patient groups are needed to find an optimal cut-off ADC value.
Directory of Open Access Journals (Sweden)
Fadi Housami
2009-01-01
Full Text Available Objectives: Measurement of bladder weight using ultrasound estimates of bladder wall thickness and bladder volume is an emerging clinical measurement technique that may have a role in the diagnosis of lower urinary tract dysfunction. We have reviewed available literature on this technique to assess current clinical status. Methods: A systematic literature search was carried out within PubMed and MedLine to identify relevant publications. These were then screened for relevance. Preliminary results from our clinical experiments using the technique are also included. Results: We identified 17 published papers concerning the technique which covered clinical studies relating ultrasound-estimated bladder wall thickness to urodynamic diagnosis in men, women, and children together with change in response to treatment of bladder outlet obstruction. The original manual technique has been challenged by a commercially available automated technique. Conclusion: Ultrasound-estimated bladder weight is a promising non-invasive technique for the categorization of storage and voiding disorders in both men and women. Further studies are needed to validate the technique and assess accuracy of diagnosis.
Weissman-Miller, Deborah
2013-11-02
Point estimation is particularly important in predicting weight loss in individuals or small groups. In this analysis, a new health response function is based on a model of human response over time to estimate long-term health outcomes from a change point in short-term linear regression. This important estimation capability is addressed for small groups and single-subject designs in pilot studies for clinical trials, medical and therapeutic clinical practice. These estimations are based on a change point given by parameters derived from short-term participant data in ordinary least squares (OLS) regression. The development of the change point in initial OLS data and the point estimations are given in a new semiparametric ratio estimator (SPRE) model. The new response function is taken as a ratio of two-parameter Weibull distributions times a prior outcome value that steps estimated outcomes forward in time, where the shape and scale parameters are estimated at the change point. The Weibull distributions used in this ratio are derived from a Kelvin model in mechanics taken here to represent human beings. A distinct feature of the SPRE model in this article is that initial treatment response for a small group or a single subject is reflected in long-term response to treatment. This model is applied to weight loss in obesity in a secondary analysis of data from a classic weight loss study, which has been selected due to the dramatic increase in obesity in the United States over the past 20 years. A very small relative error of estimated to test data is shown for obesity treatment with the weight loss medication phentermine or placebo for the test dataset. An application of SPRE in clinical medicine or occupational therapy is to estimate long-term weight loss for a single subject or a small group near the beginning of treatment.
The effect of breech presentation on the accuracy of estimated fetal weight.
McNamara, Jennifer M; Odibo, Anthony O; Macones, George A; Cahill, Alison G
2012-05-01
To determine whether fetal presentation affects the accuracy of ultrasonographic estimated fetal weight (EFW). This is a retrospective cohort study of singleton pregnancies that underwent ultrasonographic EFW within 3 weeks of delivery at a single institution from 1993 to 2008. Breech presenting fetuses were compared with those presenting cephalic. EFW using the Hadlock formula was compared with actual birth weight (ABW) and reported as mean difference and mean percentage difference. Differences were also considered categorically. Subgroup analyses were performed of women who delivered within 4 days of scan and excluding women with comorbidities. Ability to detect small and large for gestational age infants was compared. Evaluation of 3770 patients, 183 (4.9%) breech presenting and 3587 (95.1%) cephalic presenting revealed no difference in mean gram difference (-222.1 g ± 312.6 vs. -210.7 g ± 793.2, p = 0.084), respectively, or ability to accurately predict within 10% of ABW (adjusted odds ratio [AOR] 1.23; 95% CI, 0.89,1.69; p = 0.208). Subgroup analyses revealed similar results. There was no difference in the ability to detect small and large for gestational age infants. Presentation does not demonstrably affect the accuracy of ultrasonographic EFW when utilizing the Hadlock formula. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
Estimation of f-validity of Geometrical Objects with OWA Operator Weights
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Abdul Rahman
2014-01-01
Full Text Available In the age of sophisticated crimes and terrorism, there is a requirement to develop a perception based multi criteria decision making system that can reveal the hidden clues in the environment of uncertainty. The crime has no fixed dimension to be carried out in. But, still there remain some imprecise clues for the crime site investigation team and precise interpretation of these clues is impossible. That is the place where role of proposed extended fuzzy logic (FLe comes into play. Moreover, for decision making, crime site investigation team has to consider multi criteria with different weights under the uncertainty. So, Extended Fuzzy Logic and Ordered weighted Averaging (OWA may be taken together as a double folded milestone in revealing the uncertainty in the world of computational forensic. The concept of unprecisiated fuzzy logic (Flu was introduced by Zadeh. When a perfect solution cannot be given or process falls excessively costly then the role of concept of Flu comes into play. This novel concept provides the basis for FLe. In order to have a better understanding of Flu, the concept of fuzzy geometry (f-geometry is introduced. The proposed work is based on Sketching with Word technique. We have introduced some fuzzy theorems (f-theorems in proposed work. These f-theorems can be used for estimating the membership value of fuzzy objects in f-geometry. These f-objects may play vital role for identifying clues in computational forensic.
Should total landings be used to correct estimated catch in numbers or mean-weight-at-age?
DEFF Research Database (Denmark)
Lewy, Peter; Lassen, H.
1997-01-01
Many ICES fish stock assessment working groups have practised Sum Of Products, SOP, correction. This correction stems from a comparison of total weights of the known landings and the SOP over age of catch in number and mean weight-at-age, which ideally should be identical. In case of SOP...... discrepancies some countries correct catch in numbers while others correct mean weight-at-age by a common factor, the ratio between landing and SOP. The paper shows that for three sampling schemes the SOP corrections are statistically incorrect and should not be made since the SOP is an unbiased estimate...... of the total landings. Calculation of the bias of estimated catch in numbers and mean weight-at-age shows that SOP corrections of either of these estimates may increase the bias. Furthermore, for five demersal and one pelagic North Sea species it is shown that SOP discrepancies greater than 2% from...
DEFF Research Database (Denmark)
Sinding, Marianne Munk; Peters, David Alberg; Frøkjær, Jens Brøndum;
CONTROL ID: 2516296 ABSTRACT FINAL ID: P22.05 TITLE: Prediction of low birth weight: the placental T2* estimated by MRI versus the uterine artery pulsatility index AUTHORS (FIRST NAME, LAST NAME): Marianne Sinding1, David Peters2, Jens B. Frøkjær3, 4, Ole B. Christiansen1, 4, Astrid Petersen5...... (MRI) variable T2* reflects the placental oxygenation and thereby placental function. Therefore, we aimed to evaluate the performance of placental T2* in the prediction of low birth weight using the uterine artery (UtA) pulsatility index (PI) as gold standard. Methods: The study population...... was a selected, mixed population regarding the risk of low birth weight. According to our national guidelines, pregnancies with ultrasound estimated fetal weight (EFW) birth weight. We included 96 pregnancies at 20-40 weeks' gestation, of which 68 had an EFW ≥ -15% and 28...
Directory of Open Access Journals (Sweden)
Sergio Rojas-Galeano
Full Text Available BACKGROUND: The analysis of complex proteomic and genomic profiles involves the identification of significant markers within a set of hundreds or even thousands of variables that represent a high-dimensional problem space. The occurrence of noise, redundancy or combinatorial interactions in the profile makes the selection of relevant variables harder. METHODOLOGY/PRINCIPAL FINDINGS: Here we propose a method to select variables based on estimated relevance to hidden patterns. Our method combines a weighted-kernel discriminant with an iterative stochastic probability estimation algorithm to discover the relevance distribution over the set of variables. We verified the ability of our method to select predefined relevant variables in synthetic proteome-like data and then assessed its performance on biological high-dimensional problems. Experiments were run on serum proteomic datasets of infectious diseases. The resulting variable subsets achieved classification accuracies of 99% on Human African Trypanosomiasis, 91% on Tuberculosis, and 91% on Malaria serum proteomic profiles with fewer than 20% of variables selected. Our method scaled-up to dimensionalities of much higher orders of magnitude as shown with gene expression microarray datasets in which we obtained classification accuracies close to 90% with fewer than 1% of the total number of variables. CONCLUSIONS: Our method consistently found relevant variables attaining high classification accuracies across synthetic and biological datasets. Notably, it yielded very compact subsets compared to the original number of variables, which should simplify downstream biological experimentation.
WSDF: Weighting of Signed Distance Function for Camera Motion Estimation in RGB-D Data
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Pham Minh Hoang
2016-10-01
Full Text Available With the recent advent of the cost-effective Kinect, which can capture real-time high-resolution RGB and visual depth information, has opened an opportunity to significantly increase the capabilities of many automated vision based recognition including object/action classification, 3D reconstruction, etc… In this work, we address the camera motion estimation which is an important phase in 3D object reconstruction system based on RGB-D data. We segment objects by thresholding algorithm based on depth data and propose the weighting function for SDF that is called WSDF. The problem of minimizing of this function is solved by Gauss-Newton methods. We systematically evaluate our method on TUM dataset. The experimental results are measured by ATE and RPE that evaluate both global and local consistency of camera motion estimation algorithm. We demonstrate large improvements over the state-of-the-art methods on both plant and teddy3 objects and achieve the best ATE as 0.00564 and 0.0182 and the best RPE as 0.00719 and 0.00104, respectively. These experiments show that the proposed method significantly outperforms state-of-the-art techniques.
Ahlberg, C M; Kuehn, L A; Thallman, R M; Kachman, S D; Snelling, W M; Spangler, M L
2016-05-01
Birth weight (BWT) and calving difficulty (CD) were recorded on 4,579 first-parity females from the Germplasm Evaluation Program at the U.S. Meat Animal Research Center (USMARC). Both traits were analyzed using a bivariate animal model with direct and maternal effects. Calving difficulty was transformed from the USMARC scores to corresponding -scores from the standard normal distribution based on the incidence rate of the USMARC scores. Breed fraction covariates were included to estimate breed differences. Heritability estimates (SE) for BWT direct, CD direct, BWT maternal, and CD maternal were 0.34 (0.10), 0.29 (0.10), 0.15 (0.08), and 0.13 (0.08), respectively. Calving difficulty direct breed effects deviated from Angus ranged from -0.13 to 0.77 and maternal breed effects deviated from Angus ranged from -0.27 to 0.36. Hereford-, Angus-, Gelbvieh-, and Brangus-sired calves would be the least likely to require assistance at birth, whereas Chiangus-, Charolais-, and Limousin-sired calves would be the most likely to require assistance at birth. Maternal breed effects for CD were least for Simmental and Charolais and greatest for Red Angus and Chiangus. Results showed that the diverse biological types of cattle have different effects on both BWT and CD. Furthermore, results provide a mechanism whereby beef cattle producers can compare EBV for CD direct and maternal arising from disjoined and breed-specific genetic evaluations.
Zhu, Ke; 10.1214/11-AOS895
2012-01-01
This paper investigates the asymptotic theory of the quasi-maximum exponential likelihood estimators (QMELE) for ARMA--GARCH models. Under only a fractional moment condition, the strong consistency and the asymptotic normality of the global self-weighted QMELE are obtained. Based on this self-weighted QMELE, the local QMELE is showed to be asymptotically normal for the ARMA model with GARCH (finite variance) and IGARCH errors. A formal comparison of two estimators is given for some cases. A simulation study is carried out to assess the performance of these estimators, and a real example on the world crude oil price is given.
Zhu, Fangqiang; Hummer, Gerhard
2012-02-05
The weighted histogram analysis method (WHAM) has become the standard technique for the analysis of umbrella sampling simulations. In this article, we address the challenges (1) of obtaining fast and accurate solutions of the coupled nonlinear WHAM equations, (2) of quantifying the statistical errors of the resulting free energies, (3) of diagnosing possible systematic errors, and (4) of optimally allocating of the computational resources. Traditionally, the WHAM equations are solved by a fixed-point direct iteration method, despite poor convergence and possible numerical inaccuracies in the solutions. Here, we instead solve the mathematically equivalent problem of maximizing a target likelihood function, by using superlinear numerical optimization algorithms with a significantly faster convergence rate. To estimate the statistical errors in one-dimensional free energy profiles obtained from WHAM, we note that for densely spaced umbrella windows with harmonic biasing potentials, the WHAM free energy profile can be approximated by a coarse-grained free energy obtained by integrating the mean restraining forces. The statistical errors of the coarse-grained free energies can be estimated straightforwardly and then used for the WHAM results. A generalization to multidimensional WHAM is described. We also propose two simple statistical criteria to test the consistency between the histograms of adjacent umbrella windows, which help identify inadequate sampling and hysteresis in the degrees of freedom orthogonal to the reaction coordinate. Together, the estimates of the statistical errors and the diagnostics of inconsistencies in the potentials of mean force provide a basis for the efficient allocation of computational resources in free energy simulations.
Musa, Rosliza; Ali, Zalila; Baharum, Adam; Nor, Norlida Mohd
2017-08-01
The linear regression model assumes that all random error components are identically and independently distributed with constant variance. Hence, each data point provides equally precise information about the deterministic part of the total variation. In other words, the standard deviations of the error terms are constant over all values of the predictor variables. When the assumption of constant variance is violated, the ordinary least squares estimator of regression coefficient lost its property of minimum variance in the class of linear and unbiased estimators. Weighted least squares estimation are often used to maximize the efficiency of parameter estimation. A procedure that treats all of the data equally would give less precisely measured points more influence than they should have and would give highly precise points too little influence. Optimizing the weighted fitting criterion to find the parameter estimates allows the weights to determine the contribution of each observation to the final parameter estimates. This study used polynomial model with weighted least squares estimation to investigate paddy production of different paddy lots based on paddy cultivation characteristics and environmental characteristics in the area of Kedah and Perlis. The results indicated that factors affecting paddy production are mixture fertilizer application cycle, average temperature, the squared effect of average rainfall, the squared effect of pest and disease, the interaction between acreage with amount of mixture fertilizer, the interaction between paddy variety and NPK fertilizer application cycle and the interaction between pest and disease and NPK fertilizer application cycle.
Estimating landslide losses - preliminary results of a seven-State pilot project
Highland, Lynn M.
2006-01-01
reliable information on economic losses associated with landslides. Each State survey examined the availability, distribution, and inherent uncertainties of economic loss data in their study areas. Their results provide the basis for identifying the most fruitful methods of collecting landslide loss data nationally, using methods that are consistent and provide common goals. These results can enhance and establish the future directions of scientific investigation priorities by convincingly documenting landslide risks and consequences that are universal throughout the 50 States. This report is organized as follows: A general summary of the pilot project history, goals, and preliminary conclusions from the Lincoln, Neb. workshop are presented first. Internet links are then provided for each State report, which appear on the internet in PDF format and which have been placed at the end of this open-file report. A reference section follows the reports, and, lastly, an Appendix of categories of landslide loss and sources of loss information is included for the reader's information. Please note: The Oregon Geological Survey has also submitted a preliminary report on indirect loss estimation methodology, which is also linked with the others. Each State report is unique and presented in the form in which it was submitted, having been independently peer reviewed by each respective State survey. As such, no universal 'style' or format has been adopted as there have been no decisions on which inventory methods will be recommended to the 50 states, as of this writing. The reports are presented here as information for decision makers, and for the record; although several reports provide recommendations on inventory methods that could be adopted nationwide, currently no decisions have been made on adopting a uniform methodology for the States.
Feedback models allowing estimation of thresholds for self-promoting body weight gain
DEFF Research Database (Denmark)
Christiansen, Edmund; Swann, Andrew; Sørensen, Thorkild I. A.
2008-01-01
. The difference between the two situations is typically an energy imbalance of about 1% over a long period of time. THEORY: Weight gain increases basal metabolic rate. Weight gain is often associated with a decrease in physical activity, although not to such an extent that it prevents an increase in total energy...... expenditure and energy intake. Dependent on the precise balance between these effects of weight gain, they may make the body weight unstable and tend to further promote weight gain. With the aim of identifying the thresholds beyond which such self-promoting weight gain may take place, we develop a simple...... cases do they take values that make weight gain self-promoting. RESULTS: We determine the quantitative conditions under which body weight gain becomes self-promoting. We find that these conditions can easily be met, and that they are so small that they are not observable with currently available...
El Khouly, Nabih I; Elkelani, Osama A; Saleh, Said A
2017-08-01
The purpose of this study was to assess the value of combining the estimated fetal weight (EFW) and amniotic fluid index (AFI) measured in term patients early in labor with intact membranes for prediction of macrosomia. In a single center, prospective observational study, 600 patients in the first stage of labor before rupture of membranes in whom ultrasonography was performed to measure AFI and EFW, and these data were analyzed statistically to evaluate prediction of fetal macrosomia. Macrosomia occurred in 64 cases (10.6%). The AFI was significantly higher in the macrosomic group (p = 0.001). It was noted that the area under receiver operating characteristic (ROC) curves for EFW was 0.93 and that of AFI was 0.67. Based on suggested combined EFW and AFI cutoffs of 4000 g and 164 mm, respectively, the positive predictive value (PPV) for combined parameters (92.3%) was higher than that of EFW (75%) and that of AFI (27%) and the likelihood ratio for combination (93.7%) was higher than that of EFW (24.7%) and that of AFI (21%). Combined use of EFW and AFI improves prediction of macrosomia at birth rather than the EFW alone.
Directory of Open Access Journals (Sweden)
Qiutong Jin
2016-06-01
Full Text Available Estimating the spatial distribution of precipitation is an important and challenging task in hydrology, climatology, ecology, and environmental science. In order to generate a highly accurate distribution map of average annual precipitation for the Loess Plateau in China, multiple linear regression Kriging (MLRK and geographically weighted regression Kriging (GWRK methods were employed using precipitation data from the period 1980–2010 from 435 meteorological stations. The predictors in regression Kriging were selected by stepwise regression analysis from many auxiliary environmental factors, such as elevation (DEM, normalized difference vegetation index (NDVI, solar radiation, slope, and aspect. All predictor distribution maps had a 500 m spatial resolution. Validation precipitation data from 130 hydrometeorological stations were used to assess the prediction accuracies of the MLRK and GWRK approaches. Results showed that both prediction maps with a 500 m spatial resolution interpolated by MLRK and GWRK had a high accuracy and captured detailed spatial distribution data; however, MLRK produced a lower prediction error and a higher variance explanation than GWRK, although the differences were small, in contrast to conclusions from similar studies.
An Illustration of Inverse Probability Weighting to Estimate Policy-Relevant Causal Effects.
Edwards, Jessie K; Cole, Stephen R; Lesko, Catherine R; Mathews, W Christopher; Moore, Richard D; Mugavero, Michael J; Westreich, Daniel
2016-08-15
Traditional epidemiologic approaches allow us to compare counterfactual outcomes under 2 exposure distributions, usually 100% exposed and 100% unexposed. However, to estimate the population health effect of a proposed intervention, one may wish to compare factual outcomes under the observed exposure distribution to counterfactual outcomes under the exposure distribution produced by an intervention. Here, we used inverse probability weights to compare the 5-year mortality risk under observed antiretroviral therapy treatment plans to the 5-year mortality risk that would had been observed under an intervention in which all patients initiated therapy immediately upon entry into care among patients positive for human immunodeficiency virus in the US Centers for AIDS Research Network of Integrated Clinical Systems multisite cohort study between 1998 and 2013. Therapy-naïve patients (n = 14,700) were followed from entry into care until death, loss to follow-up, or censoring at 5 years or on December 31, 2013. The 5-year cumulative incidence of mortality was 11.65% under observed treatment plans and 10.10% under the intervention, yielding a risk difference of -1.57% (95% confidence interval: -3.08, -0.06). Comparing outcomes under the intervention with outcomes under observed treatment plans provides meaningful information about the potential consequences of new US guidelines to treat all patients with human immunodeficiency virus regardless of CD4 cell count under actual clinical conditions.
Energy Technology Data Exchange (ETDEWEB)
Gonen, Korcan Aysun, E-mail: aysunbalc@yahoo.com [Department of Radiology, State Hospital, Eski Cami district, Hastane street, N:1, 59300, Tekirdag (Turkey); Simsek, Mehmet Masum, E-mail: radyoloji@haydapasanumune.gov.tr [Department of Radiology, Haydarpasa Numune Training and Research Hospital, Tibbiye street, Uskudar 34200, Istanbul (Turkey)
2010-11-15
Objective: Estimation of the prognosis of infarction by using diffusion weighted imaging (DWI) and quantitative apparent diffusion coefficient (ADC) measurements. Methods: 23 patients having acute stroke symptoms with verified infarction in magnetic resonance imaging (MRI) were included in this study. Their MRI studies were performed between 6 and 12 h after the onset of their symptoms and were repeated on the fifth day. The infarction volumes were calculated by using DWI and the patients were divided into two groups as the ones having an expansion in the infarction area (group 1, n = 16) and the others having no expansion in the infarction area (group 2, n = 7). Quantitative ADC values were estimated. The groups were compared in terms of the ADC values on ADC maps obtained from DWI, performed during the between 6 and 12 h from the onset of the symptoms, referring to the core of the infarction (ADC{sub IC}), ischemic penumbra (ADC{sub P}) and the nonischemic parenchymal tissue (ADC{sub N}). P values < 0.05 were accepted to be statistically significant. Results: During the between 6 and 12 h mean infarction volume calculated by DWI was 23.3 cm{sup 3} for group 1 patients (ranging from 1.1 to 68.6) and this was found to be 40.3 cm{sup 3} (ranging from 1.8 to 91.5) on the fifth day. For the group 2 patients these values were found to be 42.1 cm{sup 3} (ranging from 1 to 94.7) and 41.9 (ranging from 1 to 94.7) for the same intervals respectively. A significant statistical result was failed to be demonstrated between the mean ADC{sub IC} and ADC{sub N} values (p = 0.350 and p = 0.229 respectively). However the comparison of the ADC{sub P} values between the groups was found to be highly significant (p < 0.001). When the differences between the ADC{sub P} and ADC{sub IC} and ADC{sub N} and ADC{sub P} were compared the results proved to be statistically significant (p = 0.038 and p < 0.001 respectively). Conclusions: We believe that ADC results that would be obtained from
Mixed Norm Estimate for Radon Transform on Weighted $L^p$ Spaces
Indian Academy of Sciences (India)
Ashisha Kumar; Swagato K Ray
2010-09-01
We will discuss about the mapping property of Radon transform on $L^p$ spaces with power weight. It will be shown that the Pitt’s inequality together with the weighted version of Hardy–Littlewood–Sobolev lemma imply weighted inequality for the Radon transform.
Ortiz, Erick; Stingl, Krunoslav; Münßinger, Jana; Braun, Christoph; Preissl, Hubert; Belardinelli, Paolo
2012-01-01
Resting state functional connectivity of MEG data was studied in 29 children (9-10 years old). The weighted phase lag index (WPLI) was employed for estimating connectivity and compared to coherence. To further evaluate the network structure, a graph analysis based on WPLI was used to determine clustering coefficient (C) and betweenness centrality (BC) as local coefficients as well as the characteristic path length (L) as a parameter for global interconnectedness. The network's modular structure was also calculated to estimate functional segregation. A seed region was identified in the central occipital area based on the power distribution at the sensor level in the alpha band. WPLI reveals a specific connectivity map different from power and coherence. BC and modularity show a strong level of connectedness in the occipital area between lateral and central sensors. C shows different isolated areas of occipital sensors. Globally, a network with the shortest L is detected in the alpha band, consistently with the local results. Our results are in agreement with findings in adults, indicating a similar functional network in children at this age in the alpha band. The integrated use of WPLI and graph analysis can help to gain a better description of resting state networks. PMID:23049617
Directory of Open Access Journals (Sweden)
Quinn Brian
2011-10-01
Full Text Available Abstract Background The purpose of this study is to explore how a patient's height and weight can be used to predict the effective dose to a reference phantom with similar height and weight from a chest abdomen pelvis computed tomography scan when machine-based parameters are unknown. Since machine-based scanning parameters can be misplaced or lost, a predictive model will enable the medical professional to quantify a patient's cumulative radiation dose. Methods One hundred mathematical phantoms of varying heights and weights were defined within an x-ray Monte Carlo based software code in order to calculate organ absorbed doses and effective doses from a chest abdomen pelvis scan. Regression analysis was used to develop an effective dose predictive model. The regression model was experimentally verified using anthropomorphic phantoms and validated against a real patient population. Results Estimates of the effective doses as calculated by the predictive model were within 10% of the estimates of the effective doses using experimentally measured absorbed doses within the anthropomorphic phantoms. Comparisons of the patient population effective doses show that the predictive model is within 33% of current methods of estimating effective dose using machine-based parameters. Conclusions A patient's height and weight can be used to estimate the effective dose from a chest abdomen pelvis computed tomography scan. The presented predictive model can be used interchangeably with current effective dose estimating techniques that rely on computed tomography machine-based techniques.
Directory of Open Access Journals (Sweden)
Davide Biagini
2011-04-01
Full Text Available To evaluate the effect of sexual neutering and age of castration on empty body weight (EBW components and estimated nitrogen excretion and efficiency, a trial was carried out on 3 groups of double-muscled Piemontese calves: early castrated (EC, 5th month of age, late castrated (LC, 12th month of age and intact males (IM, control group. Animals were fed at the same energy and protein level and slaughtered at 18th month of age. Live and slaughtering performances and EBW components were recorded, whereas N excretion was calculated by difference between diet and weight gain N content. In live and slaughtering performances, IM showed higher final, carcass and total meat weight than EC and LC (P<0.01. In EBW components, IM showed higher blood and head weight than EC and LC (P<0.01 and 0.05 respectively, and differences were found between EC and LC for head weights (P<0.01. IM showed higher body crude protein (BCP than EC and LC (P<0.01 and 0.05 respectively, but BCP/EBW ratio was higher only in IM than EC (P<0.05. Estimated N daily gain was higher in IM than EC and LC (P<0.01. Only LC showed higher excretion than IM (P<0.05, and N efficiency was higher in IM than EC and LC (P<0.05 and 0.01 respectively. In conclusion, for the Piemontese hypertrophied cattle castration significantly increases N excretion (+7% and reduces N efficiency (-15%, leading to a lower level of sustainability.
Enhanced Mean Dynamic Topography And Ocean Circulation Estimation Using Goce Preliminary Mode
DEFF Research Database (Denmark)
Knudsen, Per; Bingham, Rory; Andersen, Ole Baltazar;
2011-01-01
The Gravity and Ocean Circulation Experiment - GOCE satellite mission measure the Earth gravity field with unprecedented accuracy leading to substantial improvements in the modelling of the ocean circulation and transport. In this study of the performance of GOCE, the new preliminary gravity mode...
Yarwood, Annie; Han, Buhm; Raychaudhuri, Soumya; Bowes, John; Lunt, Mark; Pappas, Dimitrios A; Kremer, Joel; Greenberg, Jeffrey D; Plenge, Robert; Worthington, Jane; Barton, Anne; Eyre, Steve
2015-01-01
Background There is currently great interest in the incorporation of genetic susceptibility loci into screening models to identify individuals at high risk of disease. Here, we present the first risk prediction model including all 46 known genetic loci associated with rheumatoid arthritis (RA). Methods A weighted genetic risk score (wGRS) was created using 45 RA non-human leucocyte antigen (HLA) susceptibility loci, imputed amino acids at HLA-DRB1 (11, 71 and 74), HLA-DPB1 (position 9) HLA-B (position 9) and gender. The wGRS was tested in 11 366 RA cases and 15 489 healthy controls. The risk of developing RA was estimated using logistic regression by dividing the wGRS into quintiles. The ability of the wGRS to discriminate between cases and controls was assessed by receiver operator characteristic analysis and discrimination improvement tests. Results Individuals in the highest risk group showed significantly increased odds of developing anti-cyclic citrullinated peptide-positive RA compared to the lowest risk group (OR 27.13, 95% CI 23.70 to 31.05). The wGRS was validated in an independent cohort that showed similar results (area under the curve 0.78, OR 18.00, 95% CI 13.67 to 23.71). Comparison of the full wGRS with a wGRS in which HLA amino acids were replaced by a HLA tag single-nucleotide polymorphism showed a significant loss of sensitivity and specificity. Conclusions Our study suggests that in RA, even when using all known genetic susceptibility variants, prediction performance remains modest; while this is insufficiently accurate for general population screening, it may prove of more use in targeted studies. Our study has also highlighted the importance of including HLA variation in risk prediction models. PMID:24092415
Troxel, Andrea B.; Lipsitz, Stuart R.; Fitzmaurice, Garrett M.; Ibrahim, Joseph G.; Sinha, Debajyoti; Molenberghs, Geert
2010-01-01
SUMMARY For longitudinal binary data with non-monotone non-ignorably missing outcomes over time, a full likelihood approach is complicated algebraically, and with many follow-up times, maximum likelihood estimation can be computationally prohibitive. As alternatives, two pseudo-likelihood approaches have been proposed that use minimal parametric assumptions. One formulation requires specification of the marginal distributions of the outcome and missing data mechanism at each time point, but uses an “independence working assumption,” i.e., an assumption that observations are independent over time. Another method avoids having to estimate the missing data mechanism by formulating a “protective estimator.” In simulations, these two estimators can be very inefficient, both for estimating time trends in the first case and for estimating both time-varying and time-stationary effects in the second. In this paper, we propose use of the optimal weighted combination of these two estimators, and in simulations we show that the optimal weighted combination can be much more efficient than either estimator alone. Finally, the proposed method is used to analyze data from two longitudinal clinical trials of HIV-infected patients. PMID:20205269
DEFF Research Database (Denmark)
Tofts, P.S.; Brix, G; Buckley, D.L.
1999-01-01
We describe a standard set of quantity names and symbols related to the estimation of kinetic parameters from dynamic contrast-enhanced T(1)-weighted magnetic resonance imaging data, using diffusable agents such as gadopentetate dimeglumine (Gd-DTPA). These include a) the volume transfer constant K...
E. Bright; M. Oelke; A. Tubaro; P. Abrams
2010-01-01
Purpose: In the last decade interest has arisen in the use of ultrasound derived measurements of bladder wall thickness, detrusor wall thickness and ultrasound estimated bladder weight as potential diagnostic tools for conditions known to induce detrusor hypertrophy. However, to date such measuremen
Directory of Open Access Journals (Sweden)
Borges Naida C
2012-07-01
Full Text Available Abstract Background Few equations have been developed in veterinary medicine compared to human medicine to predict body composition. The present study was done to evaluate the influence of weight loss on biometry (BIO, bioimpedance analysis (BIA and ultrasonography (US in cats, proposing equations to estimate fat (FM and lean (LM body mass, as compared to dual energy x-ray absorptiometry (DXA as the referenced method. For this were used 16 gonadectomized obese cats (8 males and 8 females in a weight loss program. DXA, BIO, BIA and US were performed in the obese state (T0; obese animals, after 10% of weight loss (T1 and after 20% of weight loss (T2. Stepwise regression was used to analyze the relationship between the dependent variables (FM, LM determined by DXA and the independent variables obtained by BIO, BIA and US. The better models chosen were evaluated by a simple regression analysis and means predicted vs. determined by DXA were compared to verify the accuracy of the equations. Results The independent variables determined by BIO, BIA and US that best correlated (p r2, 19 equations were selected (12 for FM, 7 for LM; however, only 7 equations accurately predicted FM and one LM of cats. Conclusions The equations with two variables are better to use because they are effective and will be an alternative method to estimate body composition in the clinical routine. For estimated lean mass the equations using body weight associated with biometrics measures can be proposed. For estimated fat mass the equations using body weight associated with bioimpedance analysis can be proposed.
Khalil, A; D'Antonio, F; Dias, T; Cooper, D; Thilaganathan, B
2014-08-01
The aims of this study were first, to ascertain the accuracy of formulae for ultrasonographic birth-weight estimation in twin compared with singleton pregnancies and second, to assess the accuracy of sonographic examination in the prediction of birth-weight discordance in twin pregnancies. This was a retrospective cohort study including both singleton and twin pregnancies. Routine biometry was recorded and estimated fetal weight (EFW) calculated using 33 different formulae. Only pregnancies that delivered within 48 h of the ultrasound scan were included (4280 singleton and 586 twin fetuses). Differences between the EFW and actual birth weight (ABW) were assessed by percentage error, accuracy in predictions within ± 10% and ± 15% of error and use of the Bland-Altman method. The accuracy of prediction of the different cut-offs of birth-weight discordance in twin pregnancies was also assessed using the area under the receiver-operating characteristics curve (AUC). The overall mean absolute percentage error was ≤ 10% for 25 formulae in singleton pregnancies compared with three formulae in twin pregnancies. The overall predictions within ± 10% and ± 15% of the ABW were 62.2% and 81.5% in singleton and 49.7% and 68.5% in twin pregnancies, respectively. When t e formulae were categorized according to the biometric parameters included, those based on a combination of head, abdomen and femur measurements showed the lowest mean absolute percentage error, in both singleton and twin pregnancies. The predictive accuracy for 25% birth-weight discordance using the Hadlock 2 formula, as assessed by the AUC, was 0.87. Ultrasound estimation of birth weight is less accurate in twin than in singleton pregnancies. Formulae that include a combination of head, abdomen and femur measurements perform best in both singleton and twin pregnancies. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Kalantari, Mojgan; Negahdari, Arezou; Roknsharifi, Shima; Qorbani, Mostafa
2013-11-01
Abdominal circumference (AC), biparietal diameters (BPD) and femoral length (FL) are now the main parameters used to obtain estimated fetal weight (EFW). Although the role of soft tissue parameters in determining fetal weight was proved but clinical attention to mid-thigh soft tissue thickness (STT) is limited. To find the impression of STT on birth weight (BW) and represent a new predictive formula. One hundred and fourteen normal singleton term (36-42w) pregnancies with delivery within 72 hours were randomly selected to participate in this prospective cohort study. Variables measured by ultrasonography before birth included: AC, BPD, FL and STT. The actual neonatal BW was also measured after birth. Linear regression model was used and R square and p-value were reported. The mean (SD) of BW was 3406 (405) gr. R square was best fit for the model that STT was added to AC, BPD, FL (r(2): 0.77). R square for the model using BPD, AC, FL and model using BPD, STT, FL was the same (r(2): 0.7). Best fit formula was Log (BW)= 2.461+0.003BPD+0.001AC+0.007STT+0.005FL. 0.67, pSTT (R: 0.50, pSTT (p=0.001) CONCLUSION: This study showed adding STT to other variables in predictive models of fetal weight would provide a nice estimation (r(2)=0.77) and in cases that measuring AC is suboptimal STT may be a good replacement.
Institute of Scientific and Technical Information of China (English)
Osvaldo GOROSITO; Gladis PRADOLINI; Oscar SALINAS
2007-01-01
We obtain weighted distributional inequalities for multilinear commutators of the fractional integral on spaces of homogeneous type. The techniques developed in this work involve the behavior of some fractional maximal functions. In relation to these operators, as a main tool, we prove a weighted weak type boundedness result, which is interesting in itself.
Shockley, Keith R
2016-06-15
High-throughput in vitro screening experiments can be used to generate concentration-response data for large chemical libraries. It is often desirable to estimate the concentration needed to achieve a particular effect, or potency, for each chemical tested in an assay. Potency estimates can be used to directly compare chemical profiles and prioritize compounds for confirmation studies, or employed as input data for prediction modeling and association mapping. The concentration for half-maximal activity derived from the Hill equation model (i.e., AC50) is the most common potency measure applied in pharmacological research and toxicity testing. However, the AC50 parameter is subject to large uncertainty for many concentration-response relationships. In this study we introduce a new measure of potency based on a weighted Shannon entropy measure termed the weighted entropy score (WES). Our potency estimator (Point of Departure, PODWES) is defined as the concentration producing the maximum rate of change in weighted entropy along a concentration-response profile. This approach provides a new tool for potency estimation that does not depend on the assumption of monotonicity or any other pre-specified concentration-response relationship. PODWES estimates potency with greater precision and less bias compared to the conventional AC50 assessed across a range of simulated conditions.
Institute of Scientific and Technical Information of China (English)
QU Annie; XUE Lan
2009-01-01
@@ In the analysis of correlated data, it is ideal to capture the true dependence structure to increase efficiency of the estimation. However, for multivariate survival data, this is extremely challenge since the martingale residual is involved and often intractable. Fan et al. have made a significant contribution by giving a close-form formula for the optimal weights of the estimating functions such that the asymptotic variance of the estimator is minimized. Since minimizing the variance matrix is not an easy task, several strategies are proposed, such as minimizing the total variance.The most feasible one is to use the diagonal matrix entries as the weighting scheme. We congratulate them on this important work. In the following we discuss implementing of their method and relate our work to theirs.
DEFF Research Database (Denmark)
Sparrevohn, Claus Reedtz
2013-01-01
For many overfished marine stocks, recreational fishing continues even though recovery plans are implemented and commercial landings regulated. In such cases, unbiased and precise estimates of recreational harvest are important for successful management. Harvest estimation often relies on intervi......For many overfished marine stocks, recreational fishing continues even though recovery plans are implemented and commercial landings regulated. In such cases, unbiased and precise estimates of recreational harvest are important for successful management. Harvest estimation often relies...
Zeng, Dong; Gong, Changfei; Bian, Zhaoying; Huang, Jing; Zhang, Xinyu; Zhang, Hua; Lu, Lijun; Niu, Shanzhou; Zhang, Zhang; Liang, Zhengrong; Feng, Qianjin; Chen, Wufan; Ma, Jianhua
2016-11-01
Dynamic myocardial perfusion computed tomography (MPCT) is a promising technique for quick diagnosis and risk stratification of coronary artery disease. However, one major drawback of dynamic MPCT imaging is the heavy radiation dose to patients due to its dynamic image acquisition protocol. In this work, to address this issue, we present a robust dynamic MPCT deconvolution algorithm via adaptive-weighted tensor total variation (AwTTV) regularization for accurate residue function estimation with low-mA s data acquisitions. For simplicity, the presented method is termed ‘MPD-AwTTV’. More specifically, the gains of the AwTTV regularization over the original tensor total variation regularization are from the anisotropic edge property of the sequential MPCT images. To minimize the associative objective function we propose an efficient iterative optimization strategy with fast convergence rate in the framework of an iterative shrinkage/thresholding algorithm. We validate and evaluate the presented algorithm using both digital XCAT phantom and preclinical porcine data. The preliminary experimental results have demonstrated that the presented MPD-AwTTV deconvolution algorithm can achieve remarkable gains in noise-induced artifact suppression, edge detail preservation, and accurate flow-scaled residue function and MPHM estimation as compared with the other existing deconvolution algorithms in digital phantom studies, and similar gains can be obtained in the porcine data experiment.
Estimation of genetic parameters for body weight at different ages in ...
African Journals Online (AJOL)
ONOS
2010-08-09
Aug 9, 2010 ... important traits in sheep production, specially in Iran that lamb sale is the ..... ment, food availability, diseases, climatic condition (rate of rainfall .... parameters and genetic trends for live weight and fleece traits in. Menz sheep.
Error estimates of Lagrange interpolation and orthonormal expansions for Freud weights
Kwon, K. H.; Lee, D. W.
2001-08-01
Let Sn[f] be the nth partial sum of the orthonormal polynomials expansion with respect to a Freud weight. Then we obtain sufficient conditions for the boundedness of Sn[f] and discuss the speed of the convergence of Sn[f] in weighted Lp space. We also find sufficient conditions for the boundedness of the Lagrange interpolation polynomial Ln[f], whose nodal points are the zeros of orthonormal polynomials with respect to a Freud weight. In particular, if W(x)=e-(1/2)x2 is the Hermite weight function, then we obtain sufficient conditions for the inequalities to hold:andwhere and k=0,1,2...,r.
Daumas, Mathilde; Chaumoître, Kathia; Adalian, Pascal; Marchal, François
2016-03-01
Most biometric age estimation methods used in anthropological and forensic science for juveniles are based on unidimensional measurements (length or width). Here, a new method using bidimensional data was tested. A 3D morphometric analysis was performed on 108 CT scans of ilium bone of juveniles (from 20 gestational weeks to 12 years old). The sample was divided into training and validation groups. Best predictors were determined by comparing the efficiency of each variable (length, width, area, and module: a product of length and width). We established linear and polynomial regressions for each parameter for both sides. Applying the equations to the validation sample showed no significant difference between real and predicted ages. For age estimation, the area and module parameters yielded better results than unidimensional measurements. The results from this preliminary study were highly conclusive, and it would be interesting to extend the work, covering larger samples, and other bones.
Interior Lp-estimates for elliptic and parabolic Schr\\"odinger type operators and local Ap-weights
Cardoso, Isolda; Viola, Pablo; Viviani, Beatriz
2015-01-01
Let Omega be a non-empty open proper and connected subset of R^n. Consider p elliptic Schr\\"odinger type operator L_{E}u=A_{E}u+V in Omega, and the linear parabolic operator L_{P}u=A_{P}u+Vu in Omega x (0,T), where the coefficients of A_{E} and A_{P} are in VMO and the potential V satisfies a reverse-H\\"older condition. The aim of this paper is to obtain a priori estimates for the operators L_{E} and L_{P} in weighted Sobolev spaces involving the distance to the boundary and weights in a loca...
2002-01-01
This paper presents preliminary orientations for the Long-Term Plan 2003-2010. It focuses on choices in the scientific programme, savings, organisational measures and financial scenarios to deal with the cost increase of the LHC project. The paper is presented for discussion. The outcome of this discussion, as well as the observations and recommendations of the External Review Committee, which started its work while this paper was in preparation, will be taken into account for the plan which the Management is preparing for June 2002.
2002-01-01
This paper presents preliminary orientations for the Long-Term Plan 2003-2010. It focuses on choices in the scientific programme, savings, organisational measures and financial scenarios to deal with the cost increase of the LHC project. The paper is presented for discussion. The outcome of this discussion, as well as the observations and recommendations of the External Review Committee, which started its work while this paper was in preparation, will be taken into account for the plan which the Management is preparing for June 2002.
Mark H. Hansen; Gary J. Brand; Daniel G. Wendt; Ronald E. McRoberts
2001-01-01
The first year of annual FIA data collection in the North Central region was completed for 1999 in Indiana, Iowa, Minnesota, and Missouri. Estimates of timberland area, total growing-stock volume and growing-stock volume per acre are presented. These estimates are based on data from 1 year, collected at the base Federal inventory intensity, a lower intensity sample...
Institute of Scientific and Technical Information of China (English)
FAN JianQing; ZHOU Yong; CAI JianWen; CHEN Min
2009-01-01
Multivariate failure time data arise frequently in survival analysis. A commonly used technique is the working independence estimator for marginal hazard models. Two natural questions are how to improve the efficiency of the working independence estimator and how to identify the situations under which such an estimator has high statistical efficiency. In this paper, three weighted estimators are proposed based on three different optimal criteria in terms of the asymptotic covariance of weighted estimators. Simplified close-form solutions are found, which always outperform the working independence estimator. We also prove that the working independence estimator has high statistical efficiency,when asymptotic covariance of derivatives of partial log-likelihood functions is nearly exchangeable or diagonal. Simulations are conducted to compare the performance of the weighted estimator and working independence estimator. A data set from Busselton population health surveys is analyzed using the proposed estimators.
Xiaopeng, Q I; Liang, Wei; Barker, Laurie; Lekiachvili, Akaki; Xingyou, Zhang
Temperature changes are known to have significant impacts on human health. Accurate estimates of population-weighted average monthly air temperature for US counties are needed to evaluate temperature's association with health behaviours and disease, which are sampled or reported at the county level and measured on a monthly-or 30-day-basis. Most reported temperature estimates were calculated using ArcGIS, relatively few used SAS. We compared the performance of geostatistical models to estimate population-weighted average temperature in each month for counties in 48 states using ArcGIS v9.3 and SAS v 9.2 on a CITGO platform. Monthly average temperature for Jan-Dec 2007 and elevation from 5435 weather stations were used to estimate the temperature at county population centroids. County estimates were produced with elevation as a covariate. Performance of models was assessed by comparing adjusted R(2), mean squared error, root mean squared error, and processing time. Prediction accuracy for split validation was above 90% for 11 months in ArcGIS and all 12 months in SAS. Cokriging in SAS achieved higher prediction accuracy and lower estimation bias as compared to cokriging in ArcGIS. County-level estimates produced by both packages were positively correlated (adjusted R(2) range=0.95 to 0.99); accuracy and precision improved with elevation as a covariate. Both methods from ArcGIS and SAS are reliable for U.S. county-level temperature estimates; However, ArcGIS's merits in spatial data pre-processing and processing time may be important considerations for software selection, especially for multi-year or multi-state projects.
Degani, Shimon; Peleg, Dori; Bahous, Karina; Leibovitz, Zvi; Shapiro, Israel; Ohel, Gonen
2008-01-01
Objective The aim of this study was to test whether pattern recognition classifiers with multiple clinical and sonographic variables could improve ultrasound prediction of fetal macrosomia over prediction which relies on the commonly used formulas for the sonographic estimation of fetal weight. Methods The SVM algorithm was used for binary classification between two categories of weight estimation: >4000gr and macrosomia with a sensitivity of 81%, specificity of 73%, positive predictive value of 81% and negative predictive value of 73%. The comparative figures according to the combined criteria based on two commonly used formulas generated from regression analysis were 88.1%, 34%, 65.8%, 66.7%. Conclusions The SVM algorithm provides a comparable prediction of LGA fetuses as other commonly used formulas generated from regression analysis. The better specificity and better positive predictive value suggest potential value for this method and further accumulation of data may improve the reliability of this approach. PMID:22439018
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Dietz, Kelly R. [University of Minnesota, Department of Radiology, Minneapolis, MN (United States); Zhang, Lei [University of Minnesota, Biostatistical Design and Analysis Center, Minneapolis, MN (United States); Seidel, Frank G. [Lucile Packard Children' s Hospital, Department of Radiology, Stanford, CA (United States)
2015-08-15
Prior to digital radiography it was possible for a radiologist to easily estimate the size of a patient on an analog film. Because variable magnification may be applied at the time of processing an image, it is now more difficult to visually estimate an infant's size on the monitor. Since gestational age and weight significantly impact the differential diagnosis of neonatal diseases and determine the expected size of kidneys or appearance of the brain by MRI or US, this information is useful to a pediatric radiologist. Although this information may be present in the electronic medical record, it is frequently not readily available to the pediatric radiologist at the time of image interpretation. To determine if there was a correlation between gestational age and weight of a premature infant with their transverse chest diameter (rib to rib) on admission chest radiographs. This retrospective study was approved by the institutional review board, which waived informed consent. The maximum transverse chest diameter outer rib to outer rib was measured on admission portable chest radiographs of 464 patients admitted to the neonatal intensive care unit (NICU) during the 2010 calendar year. Regression analysis was used to investigate the association between chest diameter and gestational age/birth weight. Quadratic term of chest diameter was used in the regression model. Chest diameter was statistically significantly associated with both gestational age (P < 0.0001) and birth weight (P < 0.0001). An infant's gestational age and birth weight can be reliably estimated by comparing a simple measurement of the transverse chest diameter on digital chest radiograph with the tables and graphs in our study. (orig.)
Pac-bayesian bounds for sparse regression estimation with exponential weights
Alquier, Pierre
2010-01-01
We consider the sparse regression model where the number of parameters $p$ is larger than the sample size $n$. The difficulty when considering high-dimensional problems is to propose estimators achieving a good compromise between statistical and computational performances. The BIC estimator for instance performs well from the statistical point of view \\cite{BTW07} but can only be computed for values of $p$ of at most a few tens. The Lasso estimator is solution of a convex minimization problem, hence computable for large value of $p$. However stringent conditions on the design are required to establish fast rates of convergence for this estimator. Dalalyan and Tsybakov \\cite{arnak} propose a method achieving a good compromise between the statistical and computational aspects of the problem. Their estimator can be computed for reasonably large $p$ and satisfies nice statistical properties under weak assumptions on the design. However, \\cite{arnak} proposes sparsity oracle inequalities in expectation for the emp...
Correa, John B; Apolzan, John W; Shepard, Desti N; Heil, Daniel P; Rood, Jennifer C; Martin, Corby K
2016-07-01
Activity monitors such as the Actical accelerometer, the Sensewear armband, and the Intelligent Device for Energy Expenditure and Activity (IDEEA) are commonly validated against gold standards (e.g., doubly labeled water, or DLW) to determine whether they accurately measure total daily energy expenditure (TEE) or activity energy expenditure (AEE). However, little research has assessed whether these parameters or others (e.g., posture allocation) predict body weight change over time. The aims of this study were to (i) test whether estimated energy expenditure or posture allocation from the devices was associated with weight change during and following a low-calorie diet (LCD) and (ii) compare free-living TEE and AEE predictions from the devices against DLW before weight change. Eighty-seven participants from 2 clinical trials wore 2 of the 3 devices simultaneously for 1 week of a 2-week DLW period. Participants then completed an 8-week LCD and were weighed at the start and end of the LCD and 6 and 12 months after the LCD. More time spent walking at baseline, measured by the IDEEA, significantly predicted greater weight loss during the 8-week LCD. Measures of posture allocation demonstrated medium effect sizes in their relationships with weight change. Bland-Altman analyses indicated that the Sensewear and the IDEEA accurately estimated TEE, and the IDEEA accurately measured AEE. The results suggest that the ability of energy expenditure and posture allocation to predict weight change is limited, and the accuracy of TEE and AEE measurements varies across activity monitoring devices, with multi-sensor monitors demonstrating stronger validity.
Gowane, G R; Chopra, A; Prince, L L L; Paswan, C; Arora, A L
2010-03-01
(Co)variance components and genetic parameters of weight at birth (BWT), weaning (3WT), 6, 9 and 12 months of age (6WT, 9WT and 12WT, respectively) and first greasy fleece weight (GFW) of Bharat Merino sheep, maintained at Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, India, were estimated by restricted maximum likelihood, fitting six animal models with various combinations of direct and maternal effects. Data were collected over a period of 10 years (1998 to 2007). A log-likelihood ratio test was used to select the most appropriate univariate model for each trait, which was subsequently used in bivariate analysis. Heritability estimates for BWT, 3WT, 6WT, 9WT and 12WT and first GFW were 0.05 ± 0.03, 0.04 ± 0.02, 0.00, 0.03 ± 0.03, 0.09 ± 0.05 and 0.05 ± 0.03, respectively. There was no evidence for the maternal genetic effect on the traits under study. Maternal permanent environmental effect contributed 19% for BWT and 6% to 11% from 3WT to 9WT and 11% for first GFW. Maternal permanent environmental effect on the post-3WT was a carryover effect of maternal influences during pre-weaning age. A low rate of genetic progress seems possible in the flock through selection. Direct genetic correlations between body weight traits were positive and ranged from 0.36 between BWT and 6WT to 0.94 between 3WT and 6WT and between 6WT and 12WT. Genetic correlations of 3WT with 6WT, 9WT and 12WT were high and positive (0.94, 0.93 and 0.93, respectively), suggesting that genetic gain in post-3WT will be maintained if selection age is reduced to 3 months. The genetic correlations of GFW with live weights were 0.01, 0.16, 0.18, 0.40 and 0.32 for BWT, 3WT, 6WT, 9WT and 12WT, respectively. Correlations of permanent environmental effects of the dam across different traits were high and positive for all the traits (0.45 to 0.98).
Howe, Chanelle J.; Cole, Stephen R.; Chmiel, Joan S.; Muñoz, Alvaro
2011-01-01
In time-to-event analyses, artificial censoring with correction for induced selection bias using inverse probability-of-censoring weights can be used to 1) examine the natural history of a disease after effective interventions are widely available, 2) correct bias due to noncompliance with fixed or dynamic treatment regimens, and 3) estimate survival in the presence of competing risks. Artificial censoring entails censoring participants when they meet a predefined study criterion, such as exp...
Fazeli, Nima; Kim, Chang-Sei; Rashedi, Mohammad; Chappell, Alyssa; Wang, Shaohua; MacArthur, Roderick; McMurtry, M Sean; Finegan, Barry; Hahn, Jin-Oh
2014-10-01
This paper demonstrates preliminary in-human validity of a novel subject-specific approach to estimation of central aortic blood pressure (CABP) from peripheral circulatory waveforms. In this "Individualized Transfer Function" (ITF) approach, CABP is estimated in two steps. First, the circulatory dynamics of the cardiovascular system are determined via model-based system identification, in which an arterial tree model is characterized based on the circulatory waveform signals measured at the body's extremity locations. Second, CABP waveform is estimated by de-convolving peripheral circulatory waveforms from the arterial tree model. The validity of the ITF approach was demonstrated using experimental data collected from 13 cardiac surgery patients. Compared with the invasive peripheral blood pressure (BP) measurements, the ITF approach yielded significant reduction in errors associated with the estimation of CABP, including 1.9-2.6 mmHg (34-42 %) reduction in BP waveform errors (p < 0.05) as well as 5.8-9.1 mmHg (67-76 %) and 6.0-9.7 mmHg (78-85 %) reductions in systolic and pulse pressure (SP and PP) errors (p < 0.05). It also showed modest but significant improvement over the generalized transfer function approach, including 0.1 mmHg (2.6 %) reduction in BP waveform errors as well as 0.7 (20 %) and 5.0 mmHg (75 %) reductions in SP and PP errors (p < 0.05).
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Eliane Lopes Rosado
2014-03-01
Full Text Available Objective: To assess the adequacy of predictive equations for estimation of energy expenditure (EE, compared with the EE using indirect calorimetry in a sample of Brazilian and Spanish women with excess body weight Methods: It is a cross-sectional study with 92 obese adult women [26 Brazilian -G1- and 66 Spanish - G2- (aged 20-50]. Weight and height were evaluated during fasting for the calculation of body mass index and predictive equations. EE was evaluated using the open-circuit indirect calorimetry with respiratory hood. Results: In G1 and G2, it was found that the estimates obtained by Harris-Benedict, Shofield, FAO/WHO/ ONU and Henry & Rees did not differ from EE using indirect calorimetry, which presented higher values than the equations proposed by Owen, Mifflin-St Jeor and Oxford. For G1 and G2 the predictive equation closest to the value obtained by the indirect calorimetry was the FAO/WHO/ONU (7.9% and 0.46% underestimation, respectively, followed by Harris-Benedict (8.6% and 1.5% underestimation, respectively. Conclusion: The equations proposed by FAO/WHO/ ONU, Harris-Benedict, Shofield and Henry & Rees were adequate to estimate the EE in a sample of Brazilian and Spanish women with excess body weight. The other equations underestimated the EE.
Yoonseok Shin
2015-01-01
Among the recent data mining techniques available, the boosting approach has attracted a great deal of attention because of its effective learning algorithm and strong boundaries in terms of its generalization performance. However, the boosting approach has yet to be used in regression problems within the construction domain, including cost estimations, but has been actively utilized in other domains. Therefore, a boosting regression tree (BRT) is applied to cost estimations at the early stag...
A.C.D. Donkers (Bas); T. Lourenco (Tania); B.G.C. Dellaert (Benedict); D.G. Goldstein (Daniel G.)
2013-01-01
textabstract In this paper we propose the use of preferred outcome distributions as a new method to elicit individuals' value and probability weighting functions in decisions under risk. Extant approaches for the elicitation of these two key ingredients of individuals' risk attitude typically rely
Qing, Siyu
2014-01-01
The National Science Foundation (NSF) Survey of Doctorate Recipients (SDR) collects information on a sample of individuals in the United States with PhD degrees. A significant portion of the sampled individuals appear in multiple survey years and can be linked across time. Survey weights in each year are created and adjusted for oversampling and…
Sharp Weighted Estimates for a Class of n-dimensional Hardy-Steklov Operators
Institute of Scientific and Technical Information of China (English)
ZHENG QING-YU; SHI SHAO-GUANG; Ji You-qing
2011-01-01
In this paper,we study one class of n-dimensional Hardy-Steklov operators which has important applications in the technical analysis in equity markets.We establish their weighted boundedness and the corresponding operator norms on both Lp(Rn) and BMO(Rn).
Dose estimate by personal music players based on weighted output voltage
DEFF Research Database (Denmark)
Hammershøi, Dorte; Ordoñez Pizarro, Rodrigo Eduardo; Christensen, Anders Tornvig
2015-01-01
The exposure by personal music players may in future be displayed to users, as described in the current draft of EN 50332-3. The suggested procedure includes a weighting of the electrical output voltages of the music player, and does not include the significance of the earphone sensitivity. It does...
Enhanced Mean Dynamic Topography And Ocean Circulation Estimation Using Goce Preliminary Mode
DEFF Research Database (Denmark)
Knudsen, Per; Bingham, Rory; Andersen, Ole Baltazar
2011-01-01
The Gravity and Ocean Circulation Experiment - GOCE satellite mission measure the Earth gravity field with unprecedented accuracy leading to substantial improvements in the modelling of the ocean circulation and transport. In this study of the performance of GOCE, the new preliminary gravity models...... have been combined with the recent DNSC08MSS mean sea surface model to construct a global GOCE satellite-only mean dynamic topography model. At a first glance, the GOCE MDT display the well known features related to the major ocean current systems. A closer look, however, reveals that the improved...... gravity provided by the GOCE mission has enhanced the resolution and sharpened the boundary of those features. A computation of MDT slopes clearly displays the improvements in the description of the current systems. In the North Atlantic Ocean, the Gulf Stream is very well defined and the Labrador...
Forkert, Nils Daniel; Kaesemann, Philipp; Fiehler, Jens; Thomalla, Götz
2012-03-01
Acute stroke is a major cause for death and disability among adults in the western hemisphere. Time-resolved perfusion-weighted (PWI) and diffusion-weighted (DWI) MR datasets are typically used for the estimation of tissue-at-risk, which is an important variable for acute stroke therapy decision-making. Although several parameters, which can be estimated based on PWI concentration curves, have been proposed for tissue-at-risk definition in the past, the time-to-peak (TTP) or time-to-max (Tmax) parameter is used most frequently in recent trials. Unfortunately, there is no clear consensus which method should be used for estimation of Tmax or TTP maps. Consequently, tissue-at-risk estimations and following treatment decision might vary considerably with the method used. In this work, 5 PWI datasets of acute stroke patients were used to calculate TTP or Tmax maps using 10 different estimation techniques. The resulting maps were segmented using a typical threshold of +4s and the corresponding PWI-lesions were calculated. The first results suggest that the TTP or Tmax method used has a major impact on the resulting tissue-at-risk volume. Numerically, the calculated volumes differed up to a factor of 3. In general, the deconvolution-based Tmax techniques estimate the ischemic penumbra rather smaller compared to direct TTP based techniques. In conclusion, the comparison of different methods for TTP or Tmax estimation revealed high variations regarding the resulting tissue-at-risk volume, which might lead to different therapy decisions. Therefore, a consensus how TTP or Tmax maps should be calculated seems necessary.
Ishimoto, Yuichi; Ishizuka, Kentaro; Aikawa, Kiyoaki; Akagi, Masato
2004-01-01
This paper proposes a robust method for estimating the fundamental frequency (F0) in real environments. It is assumed that the spectral structure of real environmental noise varies momentarily and its energy does not distribute evenly in the time-frequency domain. Therefore, segmenting a spectrogram of speech mixed with environmental noise into narrow time-frequency regions will produce low-noise regions in which the signal-to-noise ratio is high. The proposed method estimates F0 from the per...
Shi, Yun; Xu, Peiliang; Peng, Junhuan; Shi, Chuang; Liu, Jingnan
2014-01-10
Modern observation technology has verified that measurement errors can be proportional to the true values of measurements such as GPS, VLBI baselines and LiDAR. Observational models of this type are called multiplicative error models. This paper is to extend the work of Xu and Shimada published in 2000 on multiplicative error models to analytical error analysis of quantities of practical interest and estimates of the variance of unit weight. We analytically derive the variance-covariance matrices of the three least squares (LS) adjustments, the adjusted measurements and the corrections of measurements in multiplicative error models. For quality evaluation, we construct five estimators for the variance of unit weight in association of the three LS adjustment methods. Although LiDAR measurements are contaminated with multiplicative random errors, LiDAR-based digital elevation models (DEM) have been constructed as if they were of additive random errors. We will simulate a model landslide, which is assumed to be surveyed with LiDAR, and investigate the effect of LiDAR-type multiplicative error measurements on DEM construction and its effect on the estimate of landslide mass volume from the constructed DEM.
Ali, Md. Ayub; Ohtsuki, Fumio
2000-05-01
An attempt was made to estimate the maximum increment age (MIA) in height and weight of Japanese boys and girls during the birth years 1893-1990 through the published data of the Ministry of Education, Science, Sports and Culture in Japan. In cases where the same maximum annual increment occurred in two or three successive age classes in a birth year cohort, a new formula (see Eq. 2) was developed to estimate the MIA. The existing formula for estimating MIA was modified to remove the mathematical deficiency (Eq. 1). Estimated MIA shows an overall declining trend, except in birth year cohorts 1934-1951. The effect of World War II on MIA was investigated by a dummy variable regression model. On average, during the birth years 1934-1951, MIA in height decelerated by 1.35 years in boys and 0.54 year in girls, while MIA in weight decelerated by 0.95 year in boys and 0.78 year in girls. Am. J. Hum. Biol. 12:363-370, 2000. Copyright 2000 Wiley-Liss, Inc.
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Chilenskas, A. A.; Schaefer, J. C.; Towle, W. L.; Barney, D. L.
1980-01-01
A preliminary estimate has been made of the manufacturing cost for lithium/iron sulfide cells for stationary energy-storage and electric-vehicle applications. This preliminary cost analysis indicated that the manufacturing cost (in 1979 dollars) is $24 to 41/kW-h for stationary energy-storage cells and $31 to 55/kW-h for electric-vehicle cells. The materials cost was found to contribute between 52 and 65% of this manufacturing cost. The most expensive materials and components were lithium (metal and compounds), $4.61 to $14.26/kW-h; BN felt, $4.00 to 8.50/kW-h; feed-through components, $2.40/kW-h; positive current collectors, $1.48 to 2.20/kW-h; and aluminum, $1.43 to 1.66/kW-h. The projected lithium requirements were determined for use in lithium/iron sulfide batteries and conventional uses to the year 2006. The results showed that the lithium requirements were about 275,000 short tons by 2006, which is equivalent to about 51% of presently known US resources. Of this amount, about 33% would be used in battery production and 67% consumed in conventional uses. It is expected that the lithium used in battery production would be recycled.
DEFF Research Database (Denmark)
Thorup, Vivi Mørkøre; Edwards, David; Friggens, N C
2012-01-01
Precise energy balance estimates for individual cows are of great importance to health, reproduction and feed management. Energy balance is usually calculated as energy input minus output (EBalinout), requiring measurements of feed intake and energy output sources (milk, maintenance, activity......, growth and pregnancy). Except milk yield, direct measurements of these are difficult to obtain in practice, and estimates involve considerable error sources, so limiting on-farm use. Alternatively, energy balance can be estimated from body reserve changes (EBalbody) using body weight (BW) and body...... repeated BW, a milk-free BW was derived, and from between milking repeated BW, a meal-related gutfill-free BW was derived. Changes in BW and BCS were used to calculate changes in body protein, body lipid, and thus EBalbody during the first 150 DIM. As there is no gold standard energy balance measurement...
Directory of Open Access Journals (Sweden)
Anitha Roy
2013-09-01
Full Text Available In the present study, simple phytochemical screening procedures were carried out to find the various constituents present in the ethanolic extract of Dioscorea villosa tubers. Further,estimation of Diosgenin in Dioscorea villosa tubers, was carried out by HPTLC technique. The preliminary screening showed presence of proteins, flavonoids tannins, alkaloids, phenolic compounds saponins and glycosides. The extract was chromatographed on silica gel GF254 plates with Toluene: Ethyl Acetate: Acetic Acid: Formic Acid (4: 3: 1:1 as mobile phase. Detection and quantification were performed by densitrometric scanning, at 366 nm. The average recovery of diosgenin was found to be 0.48 %. The HPTLC technique has provided a good resolution of diosgenin from other constituents present in the ethanolic extract.
DEFF Research Database (Denmark)
Olesen, Jacob Bjerring; Villagómez Hoyos, Carlos Armando; Traberg, Marie Sand
2016-01-01
varying from -40 Pa to 15 Pa with a standard deviation of 32%, and a bias of 25% found relative to the peak simulated pressure drop. This preliminary study shows that pressure can be estimated non-invasively to a depth that enables cardiac scans, and thereby, the possibility of detecting the pressure......This paper presents a method for measuring pressure changes in deep-tissue vessels using vector velocity ultrasound data. The large penetration depth is ensured by acquiring data using a low frequency phased array transducer. Vascular pressure changes are then calculated from 2-D angle...... of angle-independent vector velocities are acquired using directional synthetic aperture vector flow imaging. The obtained results are evaluated by comparison to a 3-D numerical simulation model with equivalent geometry as the designed phantom. The study showed pressure drops across the constricted phantom...
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Abdulrahman Musaiger
2015-05-01
Full Text Available [b][/b]Objective. The aim of this study was to explore some body weight concerns among females at university in five Arab countries. Methods. The sample comprised 1,134 females aged 17–32 from universities in five Arab countries: Bahrain, Egypt, Jordan, Oman and Syria. A pretested questionnaire was used to determine the aspects of body weight concern. Results. Approximately 32% – 39% of females were dissatisfied with their weight, 17% – 31% wanted their body shape to be similar to Western fashion models, and 5% – 16% believed that men preferred plump women. Of the females, 22–37% had dieted to lose weight during the six months prior to the study, and 8–15% performed exercises to improve body shape most of the time. The differences in body weight concerns were statistically significant between countries. Conclusions. Body weight concern is relatively highly prevalent among young Arab women; however the prevalence varied between countries, mainly due to differences in socio-cultural background between countries.
Zhu, Shanyou; Zhou, Chuxuan; Zhang, Guixin; Zhang, Hailong; Hua, Junwei
2017-02-01
Spatially distributed near surface air temperature at the height of 2 m is an important input parameter for the land surface models. It is of great significance in both theoretical research and practical applications to retrieve instantaneous air temperature data from remote sensing observations. An approach based on Surface Energy Balance Algorithm for Land (SEBAL) to retrieve air temperature under clear sky conditions is presented. Taking the meteorological measurement data at one station as the reference and remotely sensed data as the model input, the research estimates the air temperature by using an iterative computation. The method was applied to the area of Jiangsu province for nine scenes by using MODIS data products, as well as part of Fujian province, China based on four scenes of Landsat 8 imagery. Comparing the air temperature estimated from the proposed method with that of the meteorological station measurement, results show that the root mean square error is 1.7 and 2.6 °C at 1000 and 30 m spatial resolution respectively. Sensitivity analysis of influencing factors reveals that land surface temperature is the most sensitive to the estimation precision. Research results indicate that the method has great potentiality to be used to estimate instantaneous air temperature distribution under clear sky conditions.
Weerd, S. de; Polder, J.J.; Cohen-Overbeek, T.E.; Zimmermann, L.J.; Steegers, E.A.P.
2004-01-01
OBJECTIVE: To assess costs and effectiveness of preconception counseling for all women planning pregnancy in The Netherlands with regard to folic acid supplementation and smoking cessation counseling. STUDY DESIGN: Costs and effects were estimated based on 200,000 women approached yearly and uptake
A preliminary estimate of geoid-induced variations in repeat orbit satellite altimeter observations
Brenner, Anita C.; Beckley, B. D.; Koblinsky, C. J.
1990-01-01
Altimeter satellites are often maintained in a repeating orbit to facilitate the separation of sea-height variations from the geoid. However, atmospheric drag and solar radiation pressure cause a satellite orbit to drift. For Geosat this drift causes the ground track to vary by + or - 1 km about the nominal repeat path. This misalignment leads to an error in the estimates of sea surface height variations because of the local slope in the geoid. This error has been estimated globally for the Geosat Exact Repeat Mission using a mean sea surface constructed from Geos 3 and Seasat altimeter data. Over most of the ocean the geoid gradient is small, and the repeat-track misalignment leads to errors of only 1 to 2 cm. However, in the vicinity of trenches, continental shelves, islands, and seamounts, errors can exceed 20 cm. The estimated error is compared with direct estimates from Geosat altimetry, and a strong correlation is found in the vicinity of the Tonga and Aleutian trenches. This correlation increases as the orbit error is reduced because of the increased signal-to-noise ratio.
A preliminary estimate of geoid-induced variations in repeat orbit satellite altimeter observations
Brenner, Anita C.; Beckley, B. D.; Koblinsky, C. J.
1990-01-01
Altimeter satellites are often maintained in a repeating orbit to facilitate the separation of sea-height variations from the geoid. However, atmospheric drag and solar radiation pressure cause a satellite orbit to drift. For Geosat this drift causes the ground track to vary by + or - 1 km about the nominal repeat path. This misalignment leads to an error in the estimates of sea surface height variations because of the local slope in the geoid. This error has been estimated globally for the Geosat Exact Repeat Mission using a mean sea surface constructed from Geos 3 and Seasat altimeter data. Over most of the ocean the geoid gradient is small, and the repeat-track misalignment leads to errors of only 1 to 2 cm. However, in the vicinity of trenches, continental shelves, islands, and seamounts, errors can exceed 20 cm. The estimated error is compared with direct estimates from Geosat altimetry, and a strong correlation is found in the vicinity of the Tonga and Aleutian trenches. This correlation increases as the orbit error is reduced because of the increased signal-to-noise ratio.
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N. Zuhair Faruq
2016-07-01
Full Text Available The present paper is concerned with the formulation of an elasto-plastic strain based approach suitable for assessing fatigue strength of notched components subjected to in-service variable amplitude cyclic loading. The hypothesis is formed that the crack initiation plane is closely aligned with the plane of maximum shear strain amplitude, its orientation and the associated stress/strain quantities being determined using the Maximum Variance Method. Fatigue damage is estimated by applying the Modified Manson-Coffin Curve Method (MMCCM along with the Point Method (PM. In the proposed approach, the required critical distance is treated as a material property whose value is not affected either by the sharpness of the notch being assessed or by the profile of the load spectrum being applied. The detrimental effect of non-zero mean stresses and degree of multiaxiality of the local stress/strain histories is also considered. The accuracy and reliability of the proposed design methodology was checked against several experimental data taken from the literature and generated under different uniaxial variable amplitude load histories. In order to determine the required local stress/strain states, refined elasto-plastic finite element models were solved using commercial software ANSYS®. This preliminary validation exercise allowed us to prove that the proposed approach is capable of estimates laying within an error factor of about 2. These preliminary results are certainly promising, strongly supporting the idea that the proposed design strategy can successfully be used to assess the fatigue lifetime of notched metallic components subjected to in-service multiaxial variable amplitude loading sequences.
DEFF Research Database (Denmark)
Jensen, Bente Rona; Hovgaard-Hansen, Line; Cappelen, Katrine Louise
2016-01-01
Running on a lower-body positive pressure (LBPP) treadmill allows effects of weight support on leg muscle activation to be assessed systematically, and has the potential to facilitate rehabilitation and prevent overloading. The aim was to study the effect of running with weight support on leg...... muscle activation and to estimate relative knee and ankle joint forces. Runners performed 6-min running sessions at 2.22 m/s and 3.33 m/s, at 100, 80, 60, 40 and 20% body-weight (BW). Surface EMG, ground reaction force and running characteristics were measured. Relative knee and ankle joint forces were...... estimated. Leg muscles responded differently to unweighting during running, reflecting different relative contribution to propulsion and anti-gravity forces. At 20%BW, knee extensor EMGpeak decreased to 22% at 2.22 m/s and 28% at 3.33 m/s of 100%BW values. Plantar flexors decreased to 52% and 58% at 20%BW...
Howe, Chanelle J; Cole, Stephen R; Chmiel, Joan S; Muñoz, Alvaro
2011-03-01
In time-to-event analyses, artificial censoring with correction for induced selection bias using inverse probability-of-censoring weights can be used to 1) examine the natural history of a disease after effective interventions are widely available, 2) correct bias due to noncompliance with fixed or dynamic treatment regimens, and 3) estimate survival in the presence of competing risks. Artificial censoring entails censoring participants when they meet a predefined study criterion, such as exposure to an intervention, failure to comply, or the occurrence of a competing outcome. Inverse probability-of-censoring weights use measured common predictors of the artificial censoring mechanism and the outcome of interest to determine what the survival experience of the artificially censored participants would be had they never been exposed to the intervention, complied with their treatment regimen, or not developed the competing outcome. Even if all common predictors are appropriately measured and taken into account, in the context of small sample size and strong selection bias, inverse probability-of-censoring weights could fail because of violations in assumptions necessary to correct selection bias. The authors used an example from the Multicenter AIDS Cohort Study, 1984-2008, regarding estimation of long-term acquired immunodeficiency syndrome-free survival to demonstrate the impact of violations in necessary assumptions. Approaches to improve correction methods are discussed.
Boermans, M.A.; Kattenberg, M.A.C.
2011-01-01
We show how to estimate a Cronbach's alpha reliability coefficient in Stata after running a principal component or factor analysis. Alpha evaluates to what extent items measure the same underlying content when the items are combined into a scale or used for latent variable. Stata allows for testing
Reliability-based weighting of visual and vestibular cues in displacement estimation
Horst, A.C. ter; Koppen, M.G.M.; Selen, L.P.J.; Medendorp, W.P.
2015-01-01
When navigating through the environment, our brain needs to infer how far we move and in which direction we are heading. In this estimation process, the brain may rely on multiple sensory modalities, including the visual and vestibular systems. Previous research has mainly focused on heading estimat
Development and validation of GFR-estimating equations using diabetes, transplant and weight
DEFF Research Database (Denmark)
Stevens, L.A.; Schmid, C.H.; Zhang, Y.L.;
2009-01-01
BACKGROUND: We have reported a new equation (CKD-EPI equation) that reduces bias and improves accuracy for GFR estimation compared to the MDRD study equation while using the same four basic predictor variables: creatinine, age, sex and race. Here, we describe the development and validation of thi...
Joint estimation for curves for weight, feed intake, rate of gain, and residual feed intake
DEFF Research Database (Denmark)
Jensen, Just
2013-01-01
Rate of gain and feed efficiency are very important traits in most breeding programs for growing farm animals. Rate of gain (GAIN) is usually expressed over a certain age period and feed efficiency is often expressed as residual feed intake (RFI), defined as observed feed intake (FI) minus expected...... feed intake based on live weight (WGT) and GAIN. In any case the basic traits recorded are always WGT and FI and other the traits are derived from these records. A bivariate longitudinal random regression model were employed on 9284 individual longitudinal records of WGT and FI from 2827 bulls of six...
Preliminary estimation of Lake El'gygytgyn water balance and sediment income
Directory of Open Access Journals (Sweden)
G. Fedorov
2013-07-01
Full Text Available Modern process studies of the hydrologic balance of Lake El'gygytgyn, central Chukotka, and the sediment income from the catchment were carried out during a field campaign in spring and summer 2003. Despite high uncertainties due to the limited data, the results provide important first estimates for better understanding the modern and past sedimentation processes in this basin. Formed ca. 3.6 million years ago as a result of a meteorite impact, the basin contains one of the longest paleoclimate records in the terrestrial Arctic. Fluvial activity is concentrated over the short snowmelt period (about 20 days in second part of June. Underground outflow plays a very important role in the water balance and predominates over surface outflow. The residence time of the lake water is estimated to be about 100 yr.
Age and growth of round gobies in Lake Michigan, with preliminary mortality estimation
Huo, Bin; Madenjian, Charles P.; Xie, Cong X.; Zhao, Yingming; O'Brien, Timothy P.; Czesny, Sergiusz J.
2015-01-01
The round goby (Neogobius melanostomus) is a prevalent invasive species throughout Lake Michigan, as well as other Laurentian Great Lakes, yet little information is available on spatial variation in round goby growth within one body of water. Age and growth of round goby at three areas of Lake Michigan were studied by otolith analysis from a sample of 659 specimens collected from 2008 to 2012. Total length (TL) ranged from 48 to 131 mm for Sturgeon Bay, from 50 to 125 mm for Waukegan, and from 54 to 129 mm for Sleeping Bear Dunes. Ages ranged from 2 to 7 years for Sturgeon Bay, from 2 to 5 years for Waukegan, and from 2 to 6 years for Sleeping Bear Dunes. Area-specific and sex-specific body–otolith relationships were used to back-calculate estimates of total length at age, which were fitted to von Bertalanffy models to estimate growth rates. For both sexes, round gobies at Sleeping Bear Dunes and Waukegan grew significantly faster than those at Sturgeon Bay. However, round goby growth did not significantly differ between Sleeping Bear Dunes and Waukegan for either sex. At all three areas of Lake Michigan, males grew significantly faster than females. Based on catch curve analysis, estimates of annual mortality rates ranged from 0.79 to 0.84. These relatively high mortality rates suggested that round gobies may be under predatory control in Lake Michigan.
Hip fracture risk estimation based on principal component analysis of QCT atlas: a preliminary study
Li, Wenjun; Kornak, John; Harris, Tamara; Lu, Ying; Cheng, Xiaoguang; Lang, Thomas
2009-02-01
We aim to capture and apply 3-dimensional bone fragility features for fracture risk estimation. Using inter-subject image registration, we constructed a hip QCT atlas comprising 37 patients with hip fractures and 38 age-matched controls. In the hip atlas space, we performed principal component analysis to identify the principal components (eigen images) that showed association with hip fracture. To develop and test a hip fracture risk model based on the principal components, we randomly divided the 75 QCT scans into two groups, one serving as the training set and the other as the test set. We applied this model to estimate a fracture risk index for each test subject, and used the fracture risk indices to discriminate the fracture patients and controls. To evaluate the fracture discrimination efficacy, we performed ROC analysis and calculated the AUC (area under curve). When using the first group as the training group and the second as the test group, the AUC was 0.880, compared to conventional fracture risk estimation methods based on bone densitometry, which had AUC values ranging between 0.782 and 0.871. When using the second group as the training group, the AUC was 0.839, compared to densitometric methods with AUC values ranging between 0.767 and 0.807. Our results demonstrate that principal components derived from hip QCT atlas are associated with hip fracture. Use of such features may provide new quantitative measures of interest to osteoporosis.
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Kott Phillip S.
2014-09-01
Full Text Available This article describes a two-step calibration-weighting scheme for a stratified simple random sample of hospital emergency departments. The first step adjusts for unit nonresponse. The second increases the statistical efficiency of most estimators of interest. Both use a measure of emergency-department size and other useful auxiliary variables contained in the sampling frame. Although many survey variables are roughly a linear function of the measure of size, response is better modeled as a function of the log of that measure. Consequently the log of size is a calibration variable in the nonresponse-adjustment step, while the measure of size itself is a calibration variable in the second calibration step. Nonlinear calibration procedures are employed in both steps. We show with 2010 DAWN data that estimating variances as if a one-step calibration weighting routine had been used when there were in fact two steps can, after appropriately adjusting the finite-population correct in some sense, produce standard-error estimates that tend to be slightly conservative.
Guo, Penghong; Rivera, Daniel E.; Downs, Danielle S.; Savage, Jennifer S.
2016-01-01
Excessive gestational weight gain (i.e., weight gain during pregnancy) is a significant public health concern, and has been the recent focus of novel, control systems-based interventions. This paper develops a control-oriented dynamical systems model based on a first-principles energy balance model from the literature, which is evaluated against participant data from a study targeted to obese and overweight pregnant women. The results indicate significant under-reporting of energy intake among the participant population. A series of approaches based on system identification and state estimation are developed in the paper to better understand and characterize the extent of under-reporting; these range from back-calculating energy intake from a closed-form of the energy balance model, to a constrained semi-physical identification approach that estimates the extent of systematic under-reporting in the presence of noise and possibly missing data. Additionally, we describe an adaptive algorithm based on Kalman filtering to estimate energy intake in real-time. The approaches are illustrated with data from both simulated and actual intervention participants. PMID:27570366
Inverse Probability of Censoring Weighted Estimates of Kendall’s τ for Gap Time Analyses
Lakhal-Chaieb, Lajmi; Cook, Richard J.; Lin, Xihong
2010-01-01
In life history studies interest often lies in the analysis of the inter-event, or gap times and the association between event times. Gap time analyses are challenging however, even when the length of follow-up is determined independently of the event process, since associations between gap times induce dependent censoring for second and subsequent gap times. This paper discusses nonparametric estimation of the association between consecutive gap times based on Kendall’s τ in the presence of ...
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Djacyr Magna Cabral Freire
2010-01-01
Full Text Available OBJETIVO: avaliar a correlação entre o peso fetal estimado (PFE por ultrassonografia e o peso neonatal (PN, bem como a capacidade do PFE predizer as alterações do PN entre gestantes de João Pessoa (PB. MÉTODOS: estudo de validação diagnóstica incluindo 122 gestantes que tiveram o PFE calculado por ultrassonografia até sete dias antes do parto e o PN determinado imediatamente após o nascimento, com balança específica para recém-nascidos. A correlação entre o PFE e o PN foi avaliada pelo coeficiente de correlação de Pearson entre as duas medidas e pela média das diferenças entre elas. O PFE e o PN foram classificados em: pequeno para idade gestacional (PIG, adequado para a idade gestacional (AIG e grande para a idade gestacional (GIG, de acordo com os percentis 10 e 90 das respectivas curvas de referência. O diagnóstico de desvios do PFE foi validado utilizando a curva de valores de referência de peso neonatal de Alexander como padrão-ouro, estimando-se a sensibilidade, especificidade, valores preditivos positivo e negativo. RESULTADOS: houve uma elevada correlação linear entre o PFE e o PN (R=0,96 e a diferença entre eles variou entre -474 g e +480 g, com média de +3 g. A maioria das máximas variações percentuais da estimativa de peso esteve entre 10 e 15%. O PFE teve sensibilidade de 85,7% e especificidade de 100% para detecção de PIG, e de 100 e 77,2%, respectivamente, para GIG. CONCLUSÕES: o PFE é capaz de predizer adequadamente o PN, e a curva de PFE de referência testada teve bom desempenho no rastreamento dos desvios do crescimento fetal, quando utilizada nessa população.PURPOSE: to evaluate the correlation between the estimated fetal weight (EFW by ultrasonography and the neonatal weight (NW, as well as the EFW's capacity to predict changes in NW among pregnant women in João Pessoa, Paraíba, Brazil. METHODS: a diagnostic validation study, including 122 pregnant women who have had the EFW calculated
Practical models to estimate horizontal irradiance in clear sky conditions: Preliminary results
Energy Technology Data Exchange (ETDEWEB)
Salazar, German A.; Hernandez, Alejandro L.; Saravia, Luis R. [Department of Physics, School of Exact Sciences, National University of Salta, Bolivia Avenue 5150, 4400 Salta Capital (Argentina); INENCO (Institute of Non Conventional Energy Research), Bolivia Avenue 5150, 4400 Salta Capital (Argentina)
2010-11-15
The Argentinean Northwest (ANW) is a high altitude region located alongside Los Andes Mountains. The ANW is also one of the most insolated regions in the world due to its altitude and particular climate. However, the characterization of the solar resource in the region is incomplete as there are no stations to measure solar radiation continuously and methodically. With irradiance data recently having been measured at three sites in the Salta Province, a study was carried out that resulted in a practical model to quickly and efficiently estimate the horizontal irradiance in high altitude sites in clear sky conditions. This model uses the altitude above sea level (A) as a variable and generates a representative clearness index as a result (k{sub t-R}) that is calculated for each site studied. This index k{sub t-R} is then used with the relative optical air mass and the extraterrestrial irradiance to estimate the instantaneous clearness index (k{sub t}). Subsequently, the index k{sub t-R} is corrected by introducing the atmospheric pressure in the definition of relative optical air mass proposed by Kasten. The results are satisfactory as errors in the irradiance estimations with respect to measured values do not exceed 5% for pressure corrected air masses AM{sub c} < 2. This model will be used in a feasibility study to locate sites for the installation of solar thermal power plants in the ANW. A prototype of a CLFR solar power plant is being built in the INENCO Campus, at the National University of Salta. (author)
Patel, Niraj S; Doycheva, Iliana; Peterson, Michael R; Hooker, Jonathan; Kisselva, Tatiana; Schnabl, Bernd; Seki, Ekihiro; Sirlin, Claude B; Loomba, Rohit
2015-03-01
Little is known about how weight loss affects magnetic resonance imaging (MRI) of liver fat and volume or liver histology in patients with nonalcoholic steatohepatitis (NASH). We measured changes in liver fat and liver volume associated with weight loss by using an advanced MRI method. We analyzed data collected from a previous randomized controlled trial in which 43 adult patients with biopsy-proven NASH underwent clinical evaluation, biochemical tests, and MRI and liver biopsy analyses at the start of the study and after 24 weeks. We compared data between patients who did and did not have at least 5% decrease in body mass index (BMI) during the study period. Ten of 43 patients had at least a 5% decrease in BMI during the study period. These patients had a significant decrease in liver fat, which was based on MRI proton density fat fraction estimates (18.3% ± 7.6% to 13.6% ± 13.6%, P = .03), a relative 25.5% reduction. They also had a significant decrease in liver volume (5.3%). However, no significant changes in levels of alanine aminotransferase or aspartate aminotransferase were observed with weight loss. Thirty-three patients without at least 5% decrease in BMI had insignificant increases in estimated liver fat fraction and liver volume. A reduction in BMI of at least 5% is associated with significant decrease in liver fat and volume in patients with biopsy-proven NASH. These data should be considered in assessing effect size in studies of patients with nonalcoholic fatty liver disease or obesity that use MRI-estimated liver fat and volume as end points. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.
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José Roberto Soares Scolforo
2004-06-01
Full Text Available This research aimed at studying the behavior of volume, dry weight, oil content and fence post quantity per diametric class of candeia; to define its stack factor, with and without diametric class control; and to determine equations for estimating the main stem and branches volume, dry weight and oil content of the hole tree, trunk, branches and leaves and fencepost quantity. Data were obtained from a forest inventory carried out in a native candeia forest located in Aiuruoca county, Minas Gerais state - Brazil. Tree volume was calculated through the Huber formula and oil extraction methods employed were “the solvent method” and “vapor hauling method”. For estimation volume, dry weight, oil content and fencepost number the traditional double entry models were used. The oil weight in 1 cubic meter of wood of small dimensions, trees between 5 and 10cm, is around 6 kilos, while the oil content of the largest trees, between 40 and 45cm, is around 11 kilos. The same tendency is observed for the wood volume, without bark, and in the volume of piled up wood, although in these last situations the magnitude of quantities are different. The oil content of candeia trees present the following behavior: in the stem and branches up to 3cm of diameter with bark, it varies from 1,02% to 1,37%, respectively to plants with diameter between 5 and 10cm and between 40 and 45cm; in the branches with less than 3cm of diameter with bark, it varies from 0,33% to 0,65%,respectively, to plants between 5 and 10cm and between 40 and 45cm of diameter; in the leaves it varies from 0,28% to 0,77%, respectively, for plants between 5-10cm and between 40-45cm of diameter. The average stack factor is 1.9087 and diminishes as diameter classes increases. The best model for estimating oil content, dry weight, fence post quantity and volume is the logarithmic form of Schumacher-Hall model.
Cadena, Miguel; Azpiroz, Joaquin; Borja, Gisella; Medel, Humberto; Sandoval, Hector; Rodriguez, Fausto; Flores, Francisco; Flores, Pedro
2010-01-01
The resting energy expenditure (REE) and substrate utilization are computed by indirect calorimetry technique (ICT). The REE represents 80-85% of the total energy expenditure (TEE) but only accounts for the 7% of the actual body weight (ABW). The TEE is produced by the organs plus muscles, whereas the REE accounts only for the main organs. An important problem comes up when the REE is computed throughout the fat free mass (FFM) computation or anthropometric measurements because they do not explain the tremendous catabolic variability by ICT when subjects show the same body composition. Therefore, the aim of this work is to develop a method to compute the metabolic active weight (MAW) as a new form that may help to understand the catabolic activity of the body composition. The premise was the clino-ortho maneuver can split the ABW in two parts: one in which the MAW reflects the FFM catabolism while the second part was not considered since there is not energy requirement in it. The experiment design studied 37 young volunteers undergoing the clino-ortho maneuver during fast and postprandial conditions. The results showed REE increments of 21% during phase I (fast), while in phase II (postprandial) only 14% was achieved in ortho-postprandial. Therefore, the computed MAWs were 65.5Kg and 58Kg, respectively, when the ABW average was 70 Kg and the FFM was 50 Kg. One first conclusion was that the 15.5 Kg of the MAW above the FFM could explain a catabolic equivalence which can be exclusively related to the fast-ortho position which can help to classify exclusively the dynamic over activity of the FFM.
Identical twins in forensic genetics - Epidemiology and risk based estimation of weight of evidence.
Tvedebrink, Torben; Morling, Niels
2015-12-01
The increase in the number of forensic genetic loci used for identification purposes results in infinitesimal random match probabilities. These probabilities are computed under assumptions made for rather simple population genetic models. Often, the forensic expert reports likelihood ratios, where the alternative hypothesis is assumed not to encompass close relatives. However, this approach implies that important factors present in real human populations are discarded. This approach may be very unfavourable to the defendant. In this paper, we discuss some important aspects concerning the closest familial relationship, i.e., identical (monozygotic) twins, when reporting the weight of evidence. This can be done even when the suspect has no knowledge of an identical twin or when official records hold no twin information about the suspect. The derived expressions are not original as several authors previously have published results accounting for close familial relationships. However, we revisit the discussion to increase the awareness among forensic genetic practitioners and include new information on medical and societal factors to assess the risk of not considering a monozygotic twin as the true perpetrator. If accounting for a monozygotic twin in the weight of evidence, it implies that the likelihood ratio is truncated at a maximal value depending on the prevalence of monozygotic twins and the societal efficiency of recognising a monozygotic twin. If a monozygotic twin is considered as an alternative proposition, then data relevant for the Danish society suggests that the threshold of likelihood ratios should approximately be between 150,000 and 2,000,000 in order to take the risk of an unrecognised identical, monozygotic twin into consideration. In other societies, the threshold of the likelihood ratio in crime cases may reach other, often lower, values depending on the recognition of monozygotic twins and the age of the suspect. In general, more strictly kept
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Abbas Divan Mohaideen
2014-04-01
Full Text Available Introduction: Stroke is the leading cause of disability in the elderly and significant source of disability. In the stroke patients the occurrence of fall is one of the essential factors hindering the rehabilitation process. Asymmetrical weight bearing is the major cause for frequent falls in stroke patients. Materials & Methods: In this study 15 patients subjected to Symmetrical weight bearing along with conventional stroke training in Experimental group. Other 15 patients subjected to conventional stroke training alone in control group. After 3 months of training period the pre and post test values of frequency of falls were compared. Results: As per the study results the mean difference of reduced number of falls in experimental group was 5.8 and the mean difference of reduced number of falls in control group was 2.86. The calculated value of experimental group was 31.8 whereas in control group 14.3. Discussion: Stroke patients can be trained easily with conventional weight training exercise which is highly beneficial. Further study can be done with huge number of stroke patients. Conclusion: The study concluded that the number of falls in stroke cases were reduced significantly by using symmetrical weight training exercise and conventional stroke training compared to conventional stroke training alone
Directory of Open Access Journals (Sweden)
Mervin Chandrapal
2013-02-01
Full Text Available This paper describes the experimental testing of an actuated lower-limb exoskeleton. The exoskeleton is designed to alleviate the loading at the knee joint by supplying assistive torque. It is hypothesized that the support provided will reduce the muscular effort required to perform activities of daily living and thus facilitate the execution of these movements by those who previously had limited mobility. The exoskeleton is actuated by four pneumatic artificial muscles, each providing 150N of pulling force to assist in the flexion and extension of the knee joint. The exoskeleton system estimates the user's intended motion using muscle activity information recorded from five thigh muscles, together with the knee angle. To experimentally evaluate the performance of the device, the exoskeleton was worn by an able-bodied user, whilst performing the sit-to-stand-to-sit movement. In addition, the three intention estimation algorithms were also tested to determine the influence of the various algorithms on the support provided. The results show a significant reduction in the user's muscle activity (≈ 20% when assisted by the exoskeleton in a predictable manner.
Directory of Open Access Journals (Sweden)
Mervin Chandrapal
2013-02-01
Full Text Available This paper describes the experimental testing of an actuated lower-limb exoskeleton. The exoskeleton is designed to alleviate the loading at the knee joint by supplying assistive torque. It is hypothesized that the support provided will reduce the muscular effort required to perform activities of daily living and thus facilitate the execution of these movements by those who previously had limited mobility. The exoskeleton is actuated by four pneumatic artificial muscles, each providing 150N of pulling force to assist in the flexion and extension of the knee joint. The exoskeleton system estimates the user’s intended motion using muscle activity information recorded from five thigh muscles, together with the knee angle. To experimentally evaluate the performance of the device, the exoskeleton was worn by an able-bodied user, whilst performing the sit-to-stand-to-sit movement. In addition, the three intention estimation algorithms were also tested to determine the influence of the various algorithms on the support provided. The results show a significant reduction in the user’s muscle activity (≈ 20% when assisted by the exoskeleton in a predictable manner.
A preliminary estimate of the economic impact of the energy amplifier
Fernández, R; Rubbia, Carlo; Rubio, Juan Antonio
1996-01-01
The basic concept and the applicability of the Energy Amplifier (EA) have been exhaustively described elsewhere (Refs. [1] to [4]). The EA is essentially a source of high quality heat, produced by the nuclear cascades induced by a high intensity proton beam inside an appropriate ³beam dump² arrangement. A fraction of such ³heat² has to be transformed into electricity to run the accelerator, the rest being available for a number of different industrial applications, and in particular commercial electricity production. In this paper the economic aspects are further explored and we attempt a first order estimate of the cost of such an energy source, comparing it critically with more conventional sources. In this task we have been greatly helped by a number of people2) who have specific competence in the industrial aspects of the application. We conclude that in agreement to our previous estimates, the practical cost of high quality heat is about US /GJ, namely and times lower than the one of Coal and Natural...
Forensic age estimation from the clavicle using 1.0 T MRI—Preliminary results
DEFF Research Database (Denmark)
Larsen, Sara Tangmose; Jensen, Karl Erik; Villa, Chiara;
2014-01-01
: Motion artefacts reduced image resolution in living subjects. However, mean age at stage 4 was significantly different from mean age at stage 2 and 3. The minimum age at stage 4 was 19.8 years. Inter-observer agreement was moderate for autopsy cases and slight for living subjects. By contrasting subjects......OBJECTIVES: As forensic age estimations in the living are performed without medical indication, there is a need for the development of non-ionizing methods. This study investigates the use of 1.0T MRI to visualize the ossification status of the medial end of the clavicle. MATERIAL AND METHODS: T2...... of "incomplete fusion" (≤ stage 3 on both sides) against "fused" (at least one stage 4), agreement rate rose to moderate (K=0.414) for living subjects. Despite the low agreement rate, no subject younger than 18 years was assessed as having "fused" clavicles. CONCLUSION: At lower image resolution, a 2-stage...
Preliminary Estimation of Radioactive Cesium Concentration due to Hypothetical Accident in East Sea
Energy Technology Data Exchange (ETDEWEB)
Min, Byung-Il; Kim, Sora; Park, Kihyun; Suh, Kyung-suk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2015-10-15
The sea has no large islands, bays or capes. Its water balance is mostly determined by the inflow (Korea Strait) and outflow (Tsugaru Strait and Soya Strait) through the straits connecting it to the neighboring seas and Pacific Ocean. All of the Korean nuclear power plants are located in the coastal area, 3 sites in the east coast and 1 site in the west coast. So the Korean nuclear power plants there may be possibility that such dangerous substances spread out of the East Sea. The East Sea is a fertile fishing ground for surrounding counties. The environmental radionuclides concentration estimation is important for fish and sea plants may be contaminated by those radioactive materials. In order to simplify the problem, the experiment has been considered the many simplifying assumptions. The bed sediments are uniform over all the model domain, using the monthly mean ocean current data set and ignored effect of the facilities for damage preventions.
Preliminary Modeling of Permanent Magnet Probe Flowmeter for Voltage Signal Estimation
Energy Technology Data Exchange (ETDEWEB)
Jeong, Uiju; Kim, Sung Joong [Hanyang Univ., Seoul (Korea, Republic of); Jeong, Ji Young; Kim, Tae Joon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2013-10-15
An experimental study on performance analysis of the flowmeter has been performed. The study shows that sodium flow rate is linearly proportional to the induced voltage signal from the flowmeter under the turbulent flow condition. The experimental results support its availability in the PDRC system. But, the flowmeter should be able to measure sodium flow at low Reynolds number as well. That is because the PDRC system uses sodium natural convection for its operation. Thus, calibration of the flowmeter should be done at very low sodium flow rates. However, Von Weissenfluh et al. showed that the relationship between flow rate and measured voltage signal from the flowmeter may become non-linear at very low flow rates. The nonlinearity restricts the utilization of level sensor which provide reference flow rate in the calibration experiment. The primary objective of this study is to predict the sodium flow rate range where the induced voltage signals are linearly proportional to flow rates by estimating the induced voltage signals against sodium flow rates for a wide range of flows numerically. A commercial code FLUENT is adopted for the analysis of flow field. And MAXWELL which is an electromagnetic analysis software using a finite volume method has been used to analyze the magnetic field generated by permanent magnet of the flowmeter. The induced voltage signals have been estimated by coupling the sodium flow field and the magnetic field using FLUENT MHD module. It is expected that the PMPF voltage signals are linearly proportional to flow rates range of 0.0059 to 1.96 lps. This suggests that simple calibration technique using the linearity between flow rate and the voltage signal can be adopted in calibration of the PMPF.
Directory of Open Access Journals (Sweden)
Adriana Suely de Oliveira Melo
2008-09-01
effect of maternal, socioeconomic and obstetric variables, as well the presence of artery incisions in the 20th and 24th weeks on the fetal weight estimated at the end of pregnancy (36th week in pregnant women attended by Programa Saúde da Família, in an inland town of the northeast of Brazil. METHODS: a longitudinal study including 137 pregnant women, who have been followed up every four weeks in order to assess clinical, socioeconomic and obstetric conditions, including their weight. The uterine arteries were evaluated by Doppler in the 20th and 24th weeks, the fetal weight and the amniotic fluid index (AFI, determined in the 36th week. The initial maternal nutritional state has been determined by the body mass index (BMI, the pregnant women being classified as low weight, eutrophic, over weight and obese. Weight gain during gestation has been evaluated, according to the initial nutritional state, being classified at the end of the second and third trimester as insufficient, adequate and excessive weight gain. Analysis of variance was performed to evaluate the association of the fetal weight in the 36th week with the predictor variables, adjusted by multiple linear regression. RESULTS: an association between the fetal weight estimated in the 36th week and the mother's age (p=0.02, mother's job (p=0.02, initial nutritional state (p=0.04, weight gain in the second trimester (p=0.01, presence of incisions in the uterine arteries (p=0.02, and AFI (p=0.007 has been observed. The main factors associated to the fetal weight estimated in the 36th week, after the multiple regression analysis were: BMI at the pregnancy onset, weight gain in the second trimester, AFI and tabagism. CONCLUSIONS: in the present study, the fetal weight is positively associated with the initial maternal nutritional state, the weight gain in the second trimester and the volume of amniotic fluid, and negatively, to tabagism.
Energy Technology Data Exchange (ETDEWEB)
Dohan, Anthony; Soyer, Philippe [Hopital Lariboisiere, Assistance Publique-Hopitaux de Paris, Department of Body and Interventional Imaging, Paris Cedex 10 (France); Universite Paris-Diderot, Sorbonne Paris Cite, Paris (France); Eveno, Clarisse; Pocard, Marc [Universite Paris-Diderot, Sorbonne Paris Cite, Paris (France); Hopital Lariboisiere, Assistance Publique-Hopitaux de Paris, Surgical Oncologic and Digestive Unit, Paris Cedex 10 (France); Oprea, Raluca; Place, Vinciane; Boudiaf, Mourad [Hopital Lariboisiere, Assistance Publique-Hopitaux de Paris, Department of Body and Interventional Imaging, Paris Cedex 10 (France); Pautrat, Karine [Hopital Lariboisiere, Assistance Publique-Hopitaux de Paris, Surgical Oncologic and Digestive Unit, Paris Cedex 10 (France); Hoeffel, Christine [Hopital Robert-Debre, Department of Radiology, Reims Cedex (France)
2014-11-15
To investigate the role of diffusion-weighted magnetic resonance imaging (DWMRI) in the diagnosis of abscess-complicating fistula-in-ano. This retrospective study was approved by our Institutional Review Board and informed consent was waived. MRI examinations, including fat-suppressed T2-weighted turbo spin-echo (T2-TSE) MRI and DWMRI, of 24 patients with a fistula-in-ano, were reviewed by two independent readers for the presence and number of visible fistulas, conspicuity and apparent diffusion coefficient (ADC) measurement of suspected fistula tracks and pelvic collections. The reference standard was surgical with follow-up findings. Sensitivity was 91.2 % [95 % CI: 76 %-98 %] for T2-weighted TSE MRI and 100 % [95 % CI: 90 %-100 %] for DWMRI detecting fistulas. ADC values were lower in abscesses than in inflammatory masses (P = 0.714.10{sup -6}). The area under the ROC curve was 0.971 and the optimal cut-off ADC value was 1.186 x 10{sup -3} mm{sup 2}/s, yielding a sensitivity of 100 % [95 % CI: 77 %-100 %], a specificity of 90 % [95 % CI: 66 %-100 %], a positive predictive value of 93 % [95 % CI: 82.8 %-100 %] and a negative predictive value of 90 % [95 % CI: 78 %-100 %] for an abscess diagnosis. Fistula conspicuity was greater with DWMRI than with T2-TSE MRI for the two observers (P = 0.0034 and P = 0.0007). DWMRI shows high sensitivity and specificity for the diagnosis of perianal abscesses and helps discriminate between an abscess and inflammatory mass. Conspicuity of fistulas-in-ano is greater with DWMRI than with T2-weighted TSE MRI. (orig.)
Chacko, Sara A; Yeh, Gloria Y; Davis, Roger B; Wee, Christina C
2016-10-01
This study aimed to develop and test a novel mindfulness-based intervention (MBI) designed to control weight after bariatric surgery. Randomized, controlled pilot trial. Beth Israel Deaconess Medical Center, Boston, MA, USA. Bariatric patients 1-5 years post-surgery (n=18) were randomized to receive a 10-week MBI or a standard intervention. Primary outcomes were feasibility and acceptability of the MBI. Secondary outcomes included changes in weight, eating behaviors, psychosocial outcomes, and metabolic and inflammatory biomarkers. Qualitative exit interviews were conducted post-intervention. Major themes were coded and extracted. Attendance was excellent (6 of 9 patients attended ≥7 of 10 classes). Patients reported high satisfaction and overall benefit of the MBI. The intervention was effective in reducing emotional eating at 6 months (-4.9±13.7 in mindfulness vs. 6.2±28.4 in standard, p for between-group difference=0.03) but not weight. We also observed a significant increase in HbA1C (0.34±0.38 vs. -0.06±0.31, p=0.03). Objective measures suggested trends of an increase in perceived stress and symptoms of depression, although patients reported reduced stress reactivity, improved eating behaviors, and a desire for continued mindfulness-based support in qualitative interviews. This novel mindfulness-based approach is highly acceptable to bariatric patients post-surgery and may be effective for reducing emotional eating, although it did not improve weight or glycemic control in the short term. Longer-term studies of mindfulness-based approaches may be warranted in this population. ClinicalTrials.gov identifier NCT02603601. Copyright © 2016 Elsevier Ltd. All rights reserved.
Abubakari, Abdul-Halim; Nyarko, George; Maalinyuur, Sheila
2011-07-15
An experiment (Completely Randomized Design) was set up to determine the effects of Clay Pot Sub-surface Irrigation (CPSI) and spacing on the growth and fresh weight of lettuce (Lactuca sativa). The treatments were: CPSI with spacing; 15 x 15 cm, 20 x 20 cm and 30 x 30 cm. Control treatments were Watering Can Irrigation (WCI) with the same spacing as above. Treatments were replicated three times given a total of 18 experimental units. Eighteen large enamel basins of 50/20 cm (diameter/height) were filled with good topsoil and a clay pot buried neck deep in each of the basins. Seedlings were planted in all the eighteen basins. Five Hundred mL of wastewater was applied daily to plants in each container having either clay pot or watering can treatment. Plant height increased from 2.50 to 4.25 cm within 6 Weeks after Transplanting (WAT) under CPSI and only increased from 2.14 to 2.99 cm under WCI. The CPSI also supported better leave growth and fresh weight. The fresh weight of lettuce increased almost two fold under 15 x 15 cm spacing compared to 20 x 20 and 30 x 30 cm.
Preliminary estimates of Gulf Stream characteristics from TOPEX data and a precise gravimetric geoid
Rapp, Richard H.; Smith, Dru A.
1994-01-01
TOPEX sea surface height data has been used, with a gravimetric geoid, to calculate sea surface topography across the Gulf Stream. This topography was initially computed for nine tracks on cycles 21 to 29. Due to inaccurate geoid undulations on one track, results for eight tracks are reported. The sea surface topography estimates were used to calculate parameters that describe Gulf Stream characteristics from two models of the Gulf Stream. One model was based on a Gaussian representation of the velocity while the other was a hyperbolic representation of velocity or the sea surface topography. The parameters of the Gaussian velocity model fit were a width parameter, a maximum velocity value, and the location of the maximum velocity. The parameters of the hyperbolic sea surface topography model were the width, the height jump, position, and sea surface topography at the center of the stream. Both models were used for the eight tracks and nine cycles studied. Comparisons were made between the width parameters, the maximum velocities, and the height jumps. Some of the parameter estimates were found to be highly (0.9) correlated when the hyperbolic sea surface topography fit was carried out, but such correlations were reduced for either the Gaussian velocity fits or the hyperbolic velocity model fit. A comparison of the parameters derived from 1-year TOPEX data showed good agreement with values derived by Kelly (1991) using 2.5 years of Geosat data near 38 deg N, 66 deg W longitude. Accuracy of the geoid undulations used in the calculations was of order of +/- 16 cm with the accuracy of a geoid undulation difference equal to +/- 15 cm over a 100-km line in areas with good terrestrial data coverage. This paper demonstrates that our knowledge or geoid undulations and undulation differences, in a portion of the Gulf Stream region, is sufficiently accurate to determine characteristics of the jet when used with TOPEX altimeter data. The method used here has not been shown to
Preliminary estimates of Gulf Stream characteristics from TOPEX data and a precise gravimetric geoid
Rapp, Richard H.; Smith, Dru A.
1994-01-01
TOPEX sea surface height data has been used, with a gravimetric geoid, to calculate sea surface topography across the Gulf Stream. This topography was initially computed for nine tracks on cycles 21 to 29. Due to inaccurate geoid undulations on one track, results for eight tracks are reported. The sea surface topography estimates were used to calculate parameters that describe Gulf Stream characteristics from two models of the Gulf Stream. One model was based on a Gaussian representation of the velocity while the other was a hyperbolic representation of velocity or the sea surface topography. The parameters of the Gaussian velocity model fit were a width parameter, a maximum velocity value, and the location of the maximum velocity. The parameters of the hyperbolic sea surface topography model were the width, the height jump, position, and sea surface topography at the center of the stream. Both models were used for the eight tracks and nine cycles studied. Comparisons were made between the width parameters, the maximum velocities, and the height jumps. Some of the parameter estimates were found to be highly (0.9) correlated when the hyperbolic sea surface topography fit was carried out, but such correlations were reduced for either the Gaussian velocity fits or the hyperbolic velocity model fit. A comparison of the parameters derived from 1-year TOPEX data showed good agreement with values derived by Kelly (1991) using 2.5 years of Geosat data near 38 deg N, 66 deg W longitude. Accuracy of the geoid undulations used in the calculations was of order of +/- 16 cm with the accuracy of a geoid undulation difference equal to +/- 15 cm over a 100-km line in areas with good terrestrial data coverage. This paper demonstrates that our knowledge or geoid undulations and undulation differences, in a portion of the Gulf Stream region, is sufficiently accurate to determine characteristics of the jet when used with TOPEX altimeter data. The method used here has not been shown to
Dirtu, Alin C; Geens, Tinne; Dirinck, Eveline; Malarvannan, Govindan; Neels, Hugo; Van Gaal, Luc; Jorens, Philippe G; Covaci, Adrian
2013-09-01
Human exposure to chemicals commonly encountered in our environment, like phthalates, is routinely assessed through urinary measurement of their metabolites. A particular attention is given to the specific population groups, such as obese, for which the dietary intake of environmental chemicals is higher. To evaluate the exposure to phthalates, nine phthalate metabolites (PMs) were analyzed in urine collected from obese individuals and a control population. Obese individuals lost weight through either bariatric surgery or a conservative weight loss program with dietary and lifestyle counseling. Urine samples were also collected from the obese individuals after 3, 6 and 12months of weight loss. Individual daily intakes of the corresponding phthalate diesters were estimated based on the urinary PM concentrations. A high variability was recorded for the levels of each PM in both obese and control urine samples showing the exposure to high levels of PMs in specific subgroups. The most important PM metabolite as percentage contribution to the total PM levels was mono-ethyl phthalate followed by the metabolites of di-butyl phthalate and di 2-ethyl-hexyl phthalate (DEHP). No differences in the PM levels and profiles between obese entering the program and controls were observed. Although paralleled by a significant decrease of their weight, an increase in the urinary PM levels after 3 to 6months loss was seen. Constant figures for the estimated phthalates daily intake were observed over the studied period, suggesting that besides food consumption, other human exposure sources to phthalates (e.g. air, dust) might be also important. The weight loss treatment method followed by obese individuals influenced the correlations between PM levels, suggesting a change of the intake sources with time. Except for few gender differences recorded between the urinary DEHP metabolites correlations, no other differences were observed for the urinary PM levels as a function of age, body
Preliminary investigation to estimate soil NAPL retention using parametric pedotransfer functions
Hernádi, Hilda; Makó, András
2014-10-01
Organic liquid retention of soils is a primary input variable for modelling the nonaqueous phase liquid transport and behaviour in the subsurface. In environmental and soil physical practice, it is mainly determined by scaling based on the water retention of soils or with charts of average empirical values of organic liquid retention or the fitting parameters of hydraulic functions. Predicting the fitting parameters of organic liquid retention curves with pedotransfer functions might be a promising alternative method, but this topic has only been researched to a limited extent. Thus we investigated the applicability of different hydraulic functions (3- and 4- parameter form of the van Genuchten equation and Brutsaert equation) for fitting organic liquid retention characteristics. Multivariate linear regression was used to build and develop pedotransfer functions, modelling relations between original and transformed values of basic soil properties and organic liquid retention. We attempted to generate parametric pedotransfer functions. According to our results, the applicability of hydraulic functions for fitting nonaqueous phase liquid retention curves to the experimental data was proven. The investigations gave promising results for the possibility to estimate soil nonaqueous phase liquid retention with parametric pedotransfer functions.
Capacity estimation and preliminary strategy for reducing the release of dioxins in China
Institute of Scientific and Technical Information of China (English)
YU Gang; ZHANG Qing; HUANG Jun; CAI Zhenxiao; SUI Qian
2007-01-01
As a party of the Stockholm Convention on Persistent Organic Pollutants,China must submit its national implementation plan(NIP)for this convention.The strategy and action plan for reducing the release of dioxins in China are the most important components of the NIP.Three problems are key points for developing such strategy and action plan-what are the key sources for applying the best available technology/best environmental practice(BAT/BEP)to reduce the release of dioxins?How about the capacity for reducing the dioxins release from the key sources?Where are the areas of priority for applying BAT/BEP?This paper shows the efforts towards the solution of these problems.The list of key sources covering about half of the total dioxins release was determined considering four criteria.The capacity of key sources were estimated based on the difference between the emission factor corresponding to the actual situation in 2004 and that corresponding to the scenario that all key sources have been applied BAT/BEP to reduce the dioxins release.The priority analysis using the geographical information system(GIS)tool has revealed that eastern provinces should be of high priority in the future reduction activities of dioxins release in China.
Zhang, Lifan; Zhou, Xiang; Michal, Jennifer J.; Ding, Bo; Li, Rui; Jiang, Zhihua
2014-01-01
Birth weight is an economically important trait in pig production because it directly impacts piglet growth and survival rate. In the present study, we performed a genome wide survey of candidate genes and pathways associated with individual birth weight (IBW) using the Illumina PorcineSNP60 BeadChip on 24 high (HEBV) and 24 low estimated breeding value (LEBV) animals. These animals were selected from a reference population of 522 individuals produced by three sires and six dam lines, which were crossbreds with multiple breeds. After quality-control, 43,257 SNPs (single nucleotide polymorphisms), including 42,243 autosomal SNPs and 1,014 SNPs on chromosome X, were used in the data analysis. A total of 27 differentially selected regions (DSRs), including 1 on Sus scrofa chromosome 1 (SSC1), 1 on SSC4, 2 on SSC5, 4 on SSC6, 2 on SSC7, 5 on SSC8, 3 on SSC9, 1 on SSC14, 3 on SSC18, and 5 on SSCX, were identified to show the genome wide separations between the HEBV and LEBV groups for IBW in piglets. A DSR with the most number of significant SNPs (including 7 top 0.1% and 31 top 5% SNPs) was located on SSC6, while another DSR with the largest genetic differences in FST was found on SSC18. These regions harbor known functionally important genes involved in growth and development, such as TNFRSF9 (tumor necrosis factor receptor superfamily member 9), CA6 (carbonic anhydrase VI) and MDFIC (MyoD family inhibitor domain containing). A DSR rich in imprinting genes appeared on SSC9, which included PEG10 (paternally expressed 10), SGCE (sarcoglycan, epsilon), PPP1R9A (protein phosphatase 1, regulatory subunit 9A) and ASB4 (ankyrin repeat and SOCS box containing 4). More importantly, our present study provided evidence to support six quantitative trait loci (QTL) regions for pig birth weight, six QTL regions for average birth weight (ABW) and three QTL regions for litter birth weight (LBW) reported previously by other groups. Furthermore, gene ontology analysis with 183 genes
Tesanović, Sanda; Radman, Maja; Tesanović, Desa; Erzen, Dubravka Jurisić; Hozo, Izet
2013-06-01
We conducted this study to determine the degree of obesity influence on the hypoglycemic response of growth hormone and cortisol after weight loss of 5%. A total of 45 non-diabetic, male subjects followed in the outpatient endocrinological departments were divided into three groups comprising 15 subjects in each group, based upon body mass index (BMI) to healthy, overweight and obese group. Metformin was administered in the dose of 50 mg daily to the overweight and obese participants. Cortisol was measured at 0, 60 and 120 minutes. Growth hormone (GH) was measured at -15, 0, 30, 60, 90 and 120 minutes. Values of cortisol and GH were compared upon changes in hypothalamo-pituitary-adrenal (HPA) response to insulin induced hypoglycemia initially and after weight loss of 5% for overweight and obese participants. The BMI of the healthy group ranged 20.0-24.5 kg/m2 (median: 22.8); overweight group ranged 25.9-29.7 kg/m2 (median: 28.3); and obese group ranged 30.9-34.6 kg/m2 (median: 32.6). There were no significant differences of cortisol values among groups at 0 (chi2 = 2.0; p = 0.365); 60 (chi2 = 0.754; P = 0.686) and at 120 minutes (chi2 = 0.466; p = 0.792). The comparisons among groups were significant for differences of GH values at -15 (chi2 = 25.0; p response at -15 (Z = 4.67; p Weight loss of 5% was not enough for restoration of a normal stimulated growth hormone release and did not influence on the level of cortisol.
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Rulina Suradi
2006-12-01
Full Text Available Background Kangaroo mother care (KMC has been accepted as an effective method in nursing low birth weight infant (LBWI. However, the application of this method in the early life of infants has not been studied in Indonesia. Objective To evaluate some physiologic parameters of LBWI treated with early KMC compared to conventional method. Methods This was a randomized clinical-trial, which compared early KMC to conventional method in stabilizing LBWI in the first 4 hours of life. All LBWI (birth weight 1500-2499 g bom at Cipto Mangunkusumo Hospital and Budi Kemuliaan Matemity Hospital Jakarta were recruited consecutively in the period of November 2001 until March 2002. The inclusion criteria were spontaneous delivery, APGAR scores 13t and 5th minute 37, and parental consent. Results Sixty-four subjects distributed evenly into early KMC group and control group. One subject in the KMC group and three subjects in the control group were excluded due to respiratory distress. The mean birth weight was 2091 (SO 299.4 g in the KMC group and 2184 (SO 214.9 g inthe control group. The mean gestational-age in both groups was 35.6 (SO 3.0 weeks. There were no statistical differences in mean temperature (P=0.281, heart rate (P=0.956, and respiratory rate (P=0.898 between the two groups during the first 4 hours of life. We found a larger proportion of infants reaching the temperature of 36.5QC in the KMC group, especially at one hour (49% vs. 7%; the difference of proportion was 0.42 (95%CI 0.22 to 0.61. Conclusion Early KMC method is proved to be as safe as conventional method in stabilizing healthy LBWI.
Energy Technology Data Exchange (ETDEWEB)
SM Garrett
1998-09-28
The objectives of the two joint Russian/U.S. Leningrad Nuclear Power Plant (NPP) Unit #1 studies were the development of a safe, technically feasible, economically acceptable decom missioning strategy, and the preliminary cost evaluation of the developed strategy. The first study, resulting in the decommissioning strategy, was performed in 1996 and 1997. The preliminary cost estimation study, described in this report, was performed in 1997 and 1998. The decommissioning strategy study included the analyses of three basic RBM.K decommission- ing alternatives, refined for the Leningrad NPP Unit #1. The analyses included analysis of the requirements for the planning and preparation as well as the decommissioning phases.
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Lillian Pascoa
2013-06-01
Full Text Available We used actual and adjusted weights to 120 d and 210 d of age of 72,731 male and female Nellore calves born in 40 PMGRN - Nellore Brazil herds from 1985 to 2005 aiming to compare the effect of different definitions of contemporary groups on estimates of (covariance and genetic parameters. Four models, each one with a different structure of contemporary group (CG, were compared using the Akaike Information Criterion (AIC, the Bayesian Information Criterion (BIC, and the Consistent Akaike Information Criterion (CAIC. (Covariance estimates were obtained using a derivative-free restricted maximum likelihood procedure. Estimates of (covariances and genetic parameters were similar for the four models considered. However, the BIC and CAIC indicated that the most appropriate model for this Nellore population was the one that considered CG to be random, and sex of calf to be fixed and separate from CG, in which CG was defined as the group of calves born in the same herd, year, season of birth (trimester, and undergone the same management.
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Casal, J. I.; Garces, F.; Garcia-Sacristan, A.
1981-07-01
The sedimentation coefficients and intrinsic viscosities of ultrasonically sheared calf thymus DNA have been determined. The molecular weight estimation according to this parameters have been compared with the ones obtained from the electrophoretic migration rates based on the calibration proposed using the known molecular weight restriction fragments of X-ENA. (Author) 35 refs.
Skinner, Asheley Cockrell; Miles, Donna; Perrin, Eliana M; Coyne-Beasley, Tamera; Ford, Carol
2013-01-01
We compared parental reports of children's height and weight when the values were estimated vs. parent-measured to determine how these reports influence the estimated prevalence of childhood obesity. In the 2007 and 2008 North Carolina Child Health Assessment and Monitoring Program surveys, parents reported height and weight for children aged 3-17 years. When parents reported the values were not measured (by doctor, school, or home), they were asked to measure their child and were later called back. We categorized body mass index status using standard CDC definitions, and we used Chi-square tests and the Stuart-Maxwell test of marginal homogeneity to examine reporting differences. About 80% (n=509) of the 638 parents who reported an unmeasured height and/or weight participated in a callback and provided updated measures. Children originally classified as obese were subsequently classified as obese (67%), overweight (13%), and healthy weight (19%). An estimated 28% of younger children (children (aged ≥10 years) were reclassified on callback. Having parents who guessed the height and weight of their children and then reported updated values did not significantly change the overall population estimates of obesity. Our findings demonstrate that using parent-reported height and weight values may be sufficient to provide reasonable estimates of obesity prevalence. Systematically asking the source of height and weight information may help improve how it is applied to research of the prevalence of childhood obesity when gold-standard measurements are not available.
Danyluk, Michelle D; Schaffner, Donald W
2011-05-01
This project was undertaken to relate what is known about the behavior of Escherichia coli O157:H7 under laboratory conditions and integrate this information to what is known regarding the 2006 E. coli O157:H7 spinach outbreak in the context of a quantitative microbial risk assessment. The risk model explicitly assumes that all contamination arises from exposure in the field. Extracted data, models, and user inputs were entered into an Excel spreadsheet, and the modeling software @RISK was used to perform Monte Carlo simulations. The model predicts that cut leafy greens that are temperature abused will support the growth of E. coli O157:H7, and populations of the organism may increase by as much a 1 log CFU/day under optimal temperature conditions. When the risk model used a starting level of -1 log CFU/g, with 0.1% of incoming servings contaminated, the predicted numbers of cells per serving were within the range of best available estimates of pathogen levels during the outbreak. The model predicts that levels in the field of -1 log CFU/g and 0.1% prevalence could have resulted in an outbreak approximately the size of the 2006 E. coli O157:H7 outbreak. This quantitative microbial risk assessment model represents a preliminary framework that identifies available data and provides initial risk estimates for pathogenic E. coli in leafy greens. Data gaps include retail storage times, correlations between storage time and temperature, determining the importance of E. coli O157:H7 in leafy greens lag time models, and validation of the importance of cross-contamination during the washing process.
Tanner, Dennis; Negaard, Ashley; Huang, Rong; Evans, Neil; Hennes, Halim
2017-10-01
The aims of the study were to examine the predictive accuracy of Broselow tape (BT) weight estimation and body mass index-based weight categorization in overweight and obese pediatric patients and to develop an adjustment factor that improves the BT weight estimate in overweight and obese pediatric patients. A prospective observational study was conducted. We enrolled noncritical pediatric patients presenting to a tertiary care pediatric emergency department with nonurgent complaints. Patients had their weights, heights, abdominal circumferences, and actual BT measurements documented by research staff. One hundred seventy-eight patients aged 2 to 18 years were enrolled. Using the Centers for Disease Control and Prevention's definition of body mass index classification, 71 patients (39.89%) had normal BMI, 43 patients (24.16%) were overweight, and 64 patients (35.96%) were obese. The accuracy of the BT-estimated weight range, compared with the actual weight, is 40.5% in our study population. When stratified by BMI classification, the accuracy proportions were the following: 71.8% for normal, 41.9% for overweight, and 4.7% for obese patients. The adjustment formula ([0.014 × waistline in cm + 0.3] × BT weight) improved overall weight estimation from 40.5% to 65.2%. The greatest improvement was noted in obese children, where the BT accuracy improved from 4.7% to 59.4%. The growing pediatric obesity epidemic has challenged the BT's ability to accurately estimate the weights in overweight and obese pediatric patients. Our study demonstrated inverse relationship between the accuracy of BT and body weight. An adjustment factor significantly improved BT accuracy in obese children.
Zhang, Yonggen; Schaap, Marcel G.
2017-04-01
Pedotransfer functions (PTFs) have been widely used to predict soil hydraulic parameters in favor of expensive laboratory or field measurements. Rosetta (Schaap et al., 2001, denoted as Rosetta1) is one of many PTFs and is based on artificial neural network (ANN) analysis coupled with the bootstrap re-sampling method which allows the estimation of van Genuchten water retention parameters (van Genuchten, 1980, abbreviated here as VG), saturated hydraulic conductivity (Ks), and their uncertainties. In this study, we present an improved set of hierarchical pedotransfer functions (Rosetta3) that unify the water retention and Ks submodels into one. Parameter uncertainty of the fit of the VG curve to the original retention data is used in the ANN calibration procedure to reduce bias of parameters predicted by the new PTF. One thousand bootstrap replicas were used to calibrate the new models compared to 60 or 100 in Rosetta1, thus allowing the uni-variate and bi-variate probability distributions of predicted parameters to be quantified in greater detail. We determined the optimal weights for VG parameters and Ks, the optimal number of hidden nodes in ANN, and the number of bootstrap replicas required for statistically stable estimates. Results show that matric potential-dependent bias was reduced significantly while root mean square error (RMSE) for water content were reduced modestly; RMSE for Ks was increased by 0.9% (H3w) to 3.3% (H5w) in the new models on log scale of Ks compared with the Rosetta1 model. It was found that estimated distributions of parameters were mildly non-Gaussian and could instead be described rather well with heavy-tailed α-stable distributions. On the other hand, arithmetic means had only a small estimation bias for most textures when compared with the mean-like ;shift; parameter of the α-stable distributions. Arithmetic means and (co-)variances are therefore still recommended as summary statistics of the estimated distributions. However, it
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Solak, Aynur, E-mail: aynursolak@yahoo.com [Radiology Department of Sifa University Hospital, 35240, Fevzipasa Boulvard 172/2, Basmane, Izmir (Turkey); Şahin, Neslin, E-mail: neslinshn@gmail.com [Radiology Department of Sifa University Hospital, 35240, Fevzipasa Boulvard 172/2, Basmane, Izmir (Turkey); Genç, Berhan, E-mail: be.genc@hotmail.com [Radiology Department of Sifa University Hospital, 35240, Fevzipasa Boulvard 172/2, Basmane, Izmir (Turkey); Sever, Ali Rıza, E-mail: arsever@hotmail.com [Department of Radiology, Maidstone Hospital, Breast Unit, Maidstone, Kent (United Kingdom); Genç, Mine, E-mail: drminegenc@hotmail.com [Department of Gynecology and Obstetrics, Sifa University Hospital, 35240, Fevzipasa Boulvard 172/2, Basmane, Izmir (Turkey); Sivrikoz, Oya Nermin, E-mail: onsoral@yahoo.com [Pathology Department of Sifa University Hospital, 35240, Bornova, Izmir (Turkey)
2013-09-15
Objective: The purpose of this study is to investigate the value of susceptibility-weighted imaging (SWI) for the evaluation of cyclic morphological and hemorrhagic changes in abdominal wall endometriomas (AWE). Materials and methods: Fourteen patients with a total of 17 lesions who were admitted with complaints of abdominal wall mass and cyclic pain were evaluated by MRI. Patients were scanned during the first three days of the menstrual cycle and during the mid-cycle phase (day 13–15). In addition to conventional images SWI was performed. The signal changes within the lesions on SWI were compared and graded on both studies. Results: There was no significant difference in the size of the lesions in the early days of the menstruation compared to the mid-menstrual period. The SWI taken on mid-cycle phase showed that the center was hyperintense and the peripheral zone was hypointense in all lesions. A signal void related to increased blood and the shrinkage of complete disappearance of hyperintensity in the venter of the lesion was seen 15 (88%) of the 17 cases on the SWI series performed during the menstrual phase scan. Conclusion: SWI is a sensitive technique and has the capability to show hemorrhage and deposition of hemosiderin within the lesions. For patients suspected with AWE, valuable diagnostic findings may be obtained if the MRI examination including SWI is performed during the early and mid phase menstrual cycle.
Du, Lin; Shi, Shuo; Gong, Wei; Yang, Jian; Sun, Jia; Mao, Feiyue
2016-06-01
Hyperspectral LiDAR (HSL) is a novel tool in the field of active remote sensing, which has been widely used in many domains because of its advantageous ability of spectrum-gained. Especially in the precise monitoring of nitrogen in green plants, the HSL plays a dispensable role. The exiting HSL system used for nitrogen status monitoring has a multi-channel detector, which can improve the spectral resolution and receiving range, but maybe result in data redundancy, difficulty in system integration and high cost as well. Thus, it is necessary and urgent to pick out the nitrogen-sensitive feature wavelengths among the spectral range. The present study, aiming at solving this problem, assigns a feature weighting to each centre wavelength of HSL system by using matrix coefficient analysis and divergence threshold. The feature weighting is a criterion to amend the centre wavelength of the detector to accommodate different purpose, especially the estimation of leaf nitrogen content (LNC) in rice. By this way, the wavelengths high-correlated to the LNC can be ranked in a descending order, which are used to estimate rice LNC sequentially. In this paper, a HSL system which works based on a wide spectrum emission and a 32-channel detector is conducted to collect the reflectance spectra of rice leaf. These spectra collected by HSL cover a range of 538 nm - 910 nm with a resolution of 12 nm. These 32 wavelengths are strong absorbed by chlorophyll in green plant among this range. The relationship between the rice LNC and reflectance-based spectra is modeled using partial least squares (PLS) and support vector machines (SVMs) based on calibration and validation datasets respectively. The results indicate that I) wavelength selection method of HSL based on feature weighting is effective to choose the nitrogen-sensitive wavelengths, which can also be co-adapted with the hardware of HSL system friendly. II) The chosen wavelength has a high correlation with rice LNC which can be
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Cox Bianca
2011-07-01
Full Text Available Abstract Background Parental reports are often used in large-scale surveys to assess children's body mass index (BMI. Therefore, it is important to know to what extent these parental reports are valid and whether it makes a difference if the parents measured their children's weight and height at home or whether they simply estimated these values. The aim of this study is to compare the validity of parent-reported height, weight and BMI values of preschool children (3-7 y-old, when measured at home or estimated by parents without actual measurement. Methods The subjects were 297 Belgian preschool children (52.9% male. Participation rate was 73%. A questionnaire including questions about height and weight of the children was completed by the parents. Nurses measured height and weight following standardised procedures. International age- and sex-specific BMI cut-off values were employed to determine categories of weight status and obesity. Results On the group level, no important differences in accuracy of reported height, weight and BMI were identified between parent-measured or estimated values. However, for all 3 parameters, the correlations between parental reports and nurse measurements were higher in the group of children whose body dimensions were measured by the parents. Sensitivity for underweight and overweight/obesity were respectively 73% and 47% when parents measured their child's height and weight, and 55% and 47% when parents estimated values without measurement. Specificity for underweight and overweight/obesity were respectively 82% and 97% when parents measured the children, and 75% and 93% with parent estimations. Conclusions Diagnostic measures were more accurate when parents measured their child's weight and height at home than when those dimensions were based on parental judgements. When parent-reported data on an individual level is used, the accuracy could be improved by encouraging the parents to measure weight and height
Shen, Jincheng; Wang, Lu; Taylor, Jeremy M G
2017-06-01
Prostate cancer patients are closely followed after the initial therapy and salvage treatment may be prescribed to prevent or delay cancer recurrence. The salvage treatment decision is usually made dynamically based on the patient's evolving history of disease status and other time-dependent clinical covariates. A multi-center prostate cancer observational study has provided us data on longitudinal prostate specific antigen (PSA) measurements, time-varying salvage treatment, and cancer recurrence time. These data enable us to estimate the best dynamic regime of salvage treatment, while accounting for the complicated confounding of time-varying covariates present in the data. A Random Forest based method is used to model the probability of regime adherence and inverse probability weights are used to account for the complexity of selection bias in regime adherence. The optimal regime is then identified by the largest restricted mean survival time. We conduct simulation studies with different PSA trends to mimic both simple and complex regime adherence mechanisms. The proposed method can efficiently accommodate complex and possibly unknown adherence mechanisms, and it is robust to cases where the proportional hazards assumption is violated. We apply the method to data collected from the observational study and estimate the best salvage treatment regime in managing the risk of prostate cancer recurrence. © 2016, The International Biometric Society.
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Annalisa Pezzi
2016-11-01
Full Text Available Abstract Background Randomization procedure in randomized controlled trials (RCTs permits an unbiased estimation of causal effects. However, in clinical practice, differential compliance between arms may cause a strong violation of randomization balance and biased treatment effect among those who comply. We evaluated the effect of the consolidation phase on disease-free survival of patients with multiple myeloma in an RCT designed for another purpose, adjusting for potential selection bias due to different compliance to previous treatment phases. Methods We computed two propensity scores (PS to model two different selection processes: the first to undergo autologous stem cell transplantation, the second to begin consolidation therapy. Combined stabilized inverse probability treatment weights were then introduced in the Cox model to estimate the causal effect of consolidation therapy miming an ad hoc RCT protocol. Results We found that the effect of consolidation therapy was restricted to the first 18 months of the phase (HR: 0.40, robust 95 % CI: 0.17-0.96, after which it disappeared. Conclusions PS-based methods could be a complementary approach within an RCT context to evaluate the effect of the last phase of a complex therapeutic strategy, adjusting for potential selection bias caused by different compliance to the previous phases of the therapeutic scheme, in order to simulate an ad hoc randomization procedure. Trial registration ClinicalTrials.gov: NCT01134484 May 28, 2010 (retrospectively registered EudraCT: 2005-003723-39 December 17, 2008 (retrospectively registered
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China Supakorn
2013-02-01
Full Text Available The main objective of this study was to estimate the genetic parameters and genetic trends for birth weight (BW,heart girth (HG, and body length (BL at birth of sheep populations in Thailand. Data were collected during 1998 to 2011 fromfour livestock research and testing stations. Fixed effect testing showed that sex, herd, contemporary group and breed groupgreatly influenced on the investigated traits (P<0.05. The log likelihood ratio test showed that all traits significantly affectedby maternal additive genetic effect as well as covariance between animal effects. Estimated direct heritabilities from multivariate analysis of the model for BW, HG and BL were 0.32, 0.52 and 0.54, while estimated maternal heritabilities were 0.23,0.14 and 0.14, respectively. Positive correlations were found among direct additive genetic (0.29 to 0.97, maternal additivegenetic (0.23 to 0.95, and phenotype (0.18 to 0.96. Direct-maternal correlations within traits (-0.68 for BW, -0.92 for HG and-0.89 for BL and between traits (-0.89 to -0.08 were antagonistic effect. Direct additive genetic trends for BW, HG and BL inthe second period (2005 to 2011 were significantly increased (0.02 kg/year, 0.89 and 0.73 cm/year while maternal additivegenetic trends characteristically depicted significantly decreased (-0.01 kg/year, -0.92 and -0.72 cm/year.
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Chittawatanarat K
2012-01-01
Full Text Available Kaweesak Chittawatanarat1,2, Sakda Pruenglampoo3, Vibul Trakulhoon4, Winai Ungpinitpong5, Jayanton Patumanond21Department of Surgery, Faculty of Medicine, 2Clinical Epidemiology Unit, 3Research Institute for Health Sciences, Chiang Mai University, Chiang Mai, Thailand; 4Department of Surgery, Bhumibol Adulyadej Hospital, Bangkok, Thailand; 5Surgical Unit, Surin Hospital, Surin, ThailandBackground: Many medical procedures routinely use body weight as a parameter for calculation. However, these measurements are not always available. In addition, the commonly used visual estimation has had high error rates. Therefore, the aim of this study was to develop a predictive equation for body weight using body circumferences.Methods: A prospective study was performed in healthy volunteers. Body weight, height, and eight circumferential level parameters including neck, arm, chest, waist, umbilical level, hip, thigh, and calf were recorded. Linear regression equations were developed in a modeling sample group divided by sex and age (younger <60 years and older ≥60 years. Original regression equations were modified to simple equations by coefficients and intercepts adjustment. These equations were tested in an independent validation sample.Results: A total of 2000 volunteers were included in this study. These were randomly separated into two groups (1000 in each modeling and validation group. Equations using height and one covariate circumference were developed. After the covariate selection processes, covariate circumference of chest, waist, umbilical level, and hip were selected for single covariate equations (Sco. To reduce the body somatotype difference, the combination covariate circumferences were created by summation between the chest and one torso circumference of waist, umbilical level, or hip and used in the equation development as a combination covariate equation (Cco. Of these equations, Cco had significantly higher 10% threshold error tolerance
McCrea, Simon M; Robinson, Thomas P
2011-01-01
In this study, five consecutive patients with focal strokes and/or cortical excisions were examined with the Wechsler Adult Intelligence Scale and Wechsler Memory Scale-Fourth Editions along with a comprehensive battery of other neuropsychological tasks. All five of the lesions were large and typically involved frontal, temporal, and/or parietal lobes and were lateralized to one hemisphere. The clinical case method was used to determine the cognitive neuropsychological correlates of mental rotation (Visual Puzzles), Piagetian balance beam (Figure Weights), and visual search (Cancellation) tasks. The pattern of results on Visual Puzzles and Figure Weights suggested that both subtests involve predominately right frontoparietal networks involved in visual working memory. It appeared that Visual Puzzles could also critically rely on the integrity of the left temporoparietal junction. The left temporoparietal junction could be involved in temporal ordering and integration of local elements into a nonverbal gestalt. In contrast, the Figure Weights task appears to critically involve the right temporoparietal junction involved in numerical magnitude estimation. Cancellation was sensitive to left frontotemporal lesions and not right posterior parietal lesions typical of other visual search tasks. In addition, the Cancellation subtest was sensitive to verbal search strategies and perhaps object-based attention demands, thereby constituting a unique task in comparison with previous visual search tasks.
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Ronald C. Plotnikoff
2011-01-01
Full Text Available At a population level, the method used to determine those meeting physical activity guidelines has important implications, as estimating “sufficient” physical activity might be confounded by weight status. The objective of this study was to test the difference between three methods in estimating the prevalence of “sufficient activity” among Canadian adults with type 2 diabetes in a large population sample (N=1614 while considering the role of weight status as a potential confounder. Our results revealed that estimates of physical activity levels vary by BMI categories, depending on the methods examined. Although physical activity levels were lower in the obese, their energy expenditure estimates were not different from those who were overweight or of a healthy weight. The implications of these findings are that biased estimates of physical activity at a population level may result in inappropriate classification of adults with type 2 diabetes as “sufficiently active” and that the inclusion of body weight in estimating physical activity prevalence should be approached with caution.
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Vieira, Jose W.; Leal Neto, Viriato; Lopes Filho, Ferdinand J.; Lima Filho, Jose M.; Santana, Ivan E., E-mail: jose.wilson@recife.ifpe.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco, (IFPE), Recife, PE (Brazil); Andrade, Pedro H.A.; Cabral, Manuela O.M. [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Lima, Vanildo J.M. [Universidade Federal de Pernambuco (DA/UFPE), Recife, PE (Brazil). Departamento de Anatomia; Lima, Fernando R.A., E-mail: falima@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN/CNEN-NE), Recife, PE (Brazil)
2015-07-01
For photons and electrons, the effective dose by gender is a weighted sum of the absorbed doses in radiosensitive organs and tissue of the human body. Effective dose is estimated using Exposure Computational Models (ECM) of both genders for the same age group. The FSTA and MSTA ECMs were developed by researchers from DEN/UFPE and consist of voxel phantoms representing adults coupled to EGSnrc Monte Carlo Code, which, in the folder designed for users of EGS, codes were added to simulate some radioactive sources. The reports 60 and 103 of the ICRP provide the factors that weigh the radiosensitivity of organs and tissues (W{sub T}) required to estimate the effective dose. The two lists were placed in the FSTA and MSTA to simulate radiodiagnostic examination in different regions of the body (cranium, abdomen and thorax). The dosimetric data produced allowed an analysis of the effect of the change in the w{sub T} from the report 60 to the 103. The highest mean percent relative error, 64.3%, occurred in the results for the cranium due to the increase of the w{sub T} for most of the organs and tissues in the head and trunk in the updated list. In this case, it can be concluded that the values of the effective dose with the wT of the ICRP 60 were underestimated. Other types of simulators of radioactive sources can be used in investigating this problem and other variables related to the phantom can be considered for that proposes a W{sub T}'s list specific for the Brazilian population or recommend unrestricted use the ICRP data. (author)
Counseling for fetal macrosomia: an estimated fetal weight of 4,000 g is excessively low.
Peleg, David; Warsof, Steven; Wolf, Maya Frank; Perlitz, Yuri; Shachar, Inbar Ben
2015-01-01
Because of the known complications of fetal macrosomia, our hospital's policy has been to discuss the risks of shoulder dystocia and cesarean section (CS) in mothers with a sonographic estimated fetal weight (SEFW) ≥ 4,000 g at term. The present study was performed to determine the effect of this policy on CS rates and pregnancy outcome. We examined the pregnancy outcomes of the macrosomic (≥ 4,000 g) neonates in two cohorts of nondiabetic low risk women at term without preexisting indications for cesarean: (1) SEFW ≥ 4,000 g (correctly suspected macrosomia) and (2) SEFW macrosomia). There were 238 neonates in the correctly suspected group and 205 neonates in the unsuspected macrosomia group, respectively. Vaginal delivery was accomplished in 52.1% of the suspected group and 90.7% of the unsuspected group, respectively, p macrosomia was correctly suspected. The policy of discussing the risk of macrosomia with SEFW ≥ 4,000 g to women is not justified. A higher SEFW to trigger counseling for shoulder dystocia and CS, more consistent with American College of Obstetrics and Gynecology (ACOG) guidelines, should be considered. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
Bradley, Paul M; Journey, Celeste A; Brigham, Mark E; Burns, Douglas A; Button, Daniel T; Riva-Murray, Karen
2013-01-01
To assess inter-comparability of fluvial mercury (Hg) observations at substantially different scales, Hg concentrations, yields, and bivariate-relations were evaluated at nested-basin locations in the Edisto River, South Carolina and Hudson River, New York. Differences between scales were observed for filtered methylmercury (FMeHg) in the Edisto (attributed to wetland coverage differences) but not in the Hudson. Total mercury (THg) concentrations and bivariate-relationships did not vary substantially with scale in either basin. Combining results of this and a previously published multi-basin study, fish Hg correlated strongly with sampled water FMeHg concentration (ρ = 0.78; p = 0.003) and annual FMeHg basin yield (ρ = 0.66; p = 0.026). Improved correlation (ρ = 0.88; p < 0.0001) was achieved with time-weighted mean annual FMeHg concentrations estimated from basin-specific LOADEST models and daily streamflow. Results suggest reasonable scalability and inter-comparability for different basin sizes if wetland area or related MeHg-source-area metrics are considered.
Ozawa, Norihiko; Muragaki, Yoshihiro; Nakamura, Ryoichi; Hori, Tomokatsu; Iseki, Hiroshi
2009-02-01
The present study evaluated the shift of the pyramidal tract during resection of 17 proximal intraaxial brain tumors. In each case intraoperative diffusion-weighted (iDW) magnetic resonance imaging with a motion-probing gradient applied in the anteroposterior direction was performed using a scanner with a 0.3 T vertical magnetic field. The position of the white matter bundles containing the pyramidal tract was estimated on the coronal images before and after resection of the neoplasm, and both quantitative and directional evaluation of its displacement was done. In all cases iDW imaging provided visualization of the structure of interest. The magnitude of the pyramidal tract displacement due to removal of the neoplasm varied from 0.5 to 8.7 mm (mean 4.4 +/- 2.5 mm) on the lesion side and from 0 to 3.6 mm (mean 1.3 +/- 1.1 mm) on the normal side (p iDW imaging with updated neuronavigation.
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Cho, S H [Department of Radiation Physics, University of Texas M D Anderson Cancer Center, 1515 Holcombe Blvd, Unit 94, Houston, TX 77030 (United States)
2005-08-07
A recent mice study demonstrated that gold nanoparticles could be safely administered and used to enhance the tumour dose during radiation therapy. The use of gold nanoparticles seems more promising than earlier methods because of the high atomic number of gold and because nanoparticles can more easily penetrate the tumour vasculature. However, to date, possible dose enhancement due to the use of gold nanoparticles has not been well quantified, especially for common radiation treatment situations. Therefore, the current preliminary study estimated this dose enhancement by Monte Carlo calculations for several phantom test cases representing radiation treatments with the following modalities: 140 kVp x-rays, 4 and 6 MV photon beams, and {sup 192}Ir gamma rays. The current study considered three levels of gold concentration within the tumour, two of which are based on the aforementioned mice study, and assumed either no gold or a single gold concentration level outside the tumour. The dose enhancement over the tumour volume considered for the 140 kVp x-ray case can be at least a factor of 2 at an achievable gold concentration of 7 mg Au/g tumour assuming no gold outside the tumour. The tumour dose enhancement for the cases involving the 4 and 6 MV photon beams based on the same assumption ranged from about 1% to 7%, depending on the amount of gold within the tumour and photon beam qualities. For the {sup 192}Ir cases, the dose enhancement within the tumour region ranged from 5% to 31%, depending on radial distance and gold concentration level within the tumour. For the 7 mg Au/g tumour cases, the loading of gold into surrounding normal tissue at 2 mg Au/g resulted in an increase in the normal tissue dose, up to 30%, negligible, and about 2% for the 140 kVp x-rays, 6 MV photon beam, and {sup 192}Ir gamma rays, respectively, while the magnitude of dose enhancement within the tumour was essentially unchanged. (note)
Cho, Sang Hyun
2005-08-07
A recent mice study demonstrated that gold nanoparticles could be safely administered and used to enhance the tumour dose during radiation therapy. The use of gold nanoparticles seems more promising than earlier methods because of the high atomic number of gold and because nanoparticles can more easily penetrate the tumour vasculature. However, to date, possible dose enhancement due to the use of gold nanoparticles has not been well quantified, especially for common radiation treatment situations. Therefore, the current preliminary study estimated this dose enhancement by Monte Carlo calculations for several phantom test cases representing radiation treatments with the following modalities: 140 kVp x-rays, 4 and 6 MV photon beams, and 192Ir gamma rays. The current study considered three levels of gold concentration within the tumour, two of which are based on the aforementioned mice study, and assumed either no gold or a single gold concentration level outside the tumour. The dose enhancement over the tumour volume considered for the 140 kVp x-ray case can be at least a factor of 2 at an achievable gold concentration of 7 mg Au/g tumour assuming no gold outside the tumour. The tumour dose enhancement for the cases involving the 4 and 6 MV photon beams based on the same assumption ranged from about 1% to 7%, depending on the amount of gold within the tumour and photon beam qualities. For the 192Ir cases, the dose enhancement within the tumour region ranged from 5% to 31%, depending on radial distance and gold concentration level within the tumour. For the 7 mg Au/g tumour cases, the loading of gold into surrounding normal tissue at 2 mg Au/g resulted in an increase in the normal tissue dose, up to 30%, negligible, and about 2% for the 140 kVp x-rays, 6 MV photon beam, and 192Ir gamma rays, respectively, while the magnitude of dose enhancement within the tumour was essentially unchanged.
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Wenzel, Tom P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Technologies Area. Building Technology and Urban Systems Division
2016-08-22
This report recalculates the estimated relationship between vehicle mass and societal fatality risk, using alternative groupings by vehicle weight, to test whether the trend of decreasing fatality risk from mass reduction as case vehicle mass increases, holds over smaller increments of the range in case vehicle masses. The NHTSA baseline regression model estimates the relationship using for two weight groups for cars and light trucks; we re-estimated the mass reduction coefficients using four, six, and eight bins of vehicle mass. The estimated effect of mass reduction on societal fatality risk was not consistent over the range in vehicle masses in these weight bins. These results suggest that the relationship indicated by the NHTSA baseline model is a result of other, unmeasured attributes of the mix of vehicles in the lighter vs. heavier weight bins, and not necessarily the result of a correlation between mass reduction and societal fatality risk. An analysis of the average vehicle, driver, and crash characteristics across the various weight groupings did not reveal any strong trends that might explain the lack of a consistent trend of decreasing fatality risk from mass reduction in heavier vehicles.
Institute of Scientific and Technical Information of China (English)
JIANG Jingfei; ZHANG Jianqiu
2012-01-01
In this paper,the source localization by utilizing the measurements of a single electromagnetic (EM) vector-sensor is investigated in the framework of the geometric algebra of Euclidean 3-space.In order to describe the orthogonality among the electric and magnetic measurements,two multivectors of the geometric algebra of Euclidean 3-space (G3) are used to model the outputs of a spatially collocated EM vector-sensor.Two estimators for the wave propagation vector estimation are then formulated by the inner product between a vector and a bivector in the G3.Since the information used by the two estimators is different,a weighted inner product estimator is then proposed to fuse the two estimators together in the sense of the minimum mean square error (MMSE).Analytical results show that the statistical performances of the weighted inner product estimator are always better than its traditional cross product counterpart.The efficacy of the weighted inner product estimator and the correctness of the analytical predictions are demonstrated by simulation results.
Zare, Ali; Mahmoodi, Mahmood; Mohammad, Kazem; Zeraati, Hojjat; Hosseini, Mostafa; Holakouie Naieni, Kourosh
2014-01-01
The 5-year survival rate is a good prognostic indicator for patients with Gastric cancer that is usually estimated based on Kaplan-Meier. In situations where censored observations are too many, this method produces biased estimations. This study aimed to compare estimations of Kaplan-Meier and Weighted Kaplan-Meier as an alternative method to deal with the problem of heavy-censoring. Data from 330 patients with Gastric cancer who had undergone surgery at Iran Cancer Institute from 1995- 1999 were analyzed. The Survival Time of these patients was determined after surgery, and the 5-year survival rate for these patients was evaluated based on Kaplan-Meier and Weighted Kaplan-Meier methods. A total of 239 (72.4%) patients passed away by the end of the study and 91(27.6%) patients were censored. The mean and median of survival time for these patients were 24.86±23.73 and 16.33 months, respectively. The one-year, two-year, three-year, four-year, and five-year survival rates of these patients with standard error estimation based on Kaplan-Meier were 0.66 (0.0264), 0.42 (0.0284), 0.31 (0.0274), 0.26 (0.0264) and 0.21 (0.0256) months, respectively. The estimations of Weighted Kaplan-Meier for these patients were 0.62 (0.0251), 0.35 (0.0237), 0.24 (0.0211), 0.17 (0.0172), and 0.10 (0.0125) months, consecutively. In cases where censoring assumption is not made, and the study has many censored observations, estimations obtained from the Kaplan-Meier are biased and are estimated higher than its real amount. But Weighted Kaplan-Meier decreases bias of survival probabilities by providing appropriate weights and presents more accurate understanding.
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Ali Zare
2014-10-01
Full Text Available The 5-year survival rate is a good prognostic indicator for patients with Gastric cancer that is usually estimated based on Kaplan-Meier. In situations where censored observations are too many, this method produces biased estimations. This study aimed to compare estimations of Kaplan-Meier and Weighted Kaplan-Meier as an alternative method to deal with the problem of heavy-censoring. Data from 330 patients with Gastric cancer who had undergone surgery at Iran Cancer Institute from 1995- 1999 were analyzed. The Survival Time of these patients was determined after surgery, and the 5-year survival rate for these patients was evaluated based on Kaplan-Meier and Weighted Kaplan-Meier methods. A total of 239 (72.4% patients passed away by the end of the study and 91(27.6% patients were censored. The mean and median of survival time for these patients were 24.86±23.73 and 16.33 months, respectively. The one-year, two-year, three-year, four-year, and five-year survival rates of these patients with standard error estimation based on Kaplan-Meier were 0.66 (0.0264, 0.42 (0.0284, 0.31 (0.0274, 0.26 (0.0264 and 0.21 (0.0256 months, respectively. The estimations of Weighted Kaplan-Meier for these patients were 0.62 (0.0251, 0.35 (0.0237, 0.24 (0.0211, 0.17 (0.0172, and 0.10 (0.0125 months, consecutively. In cases where censoring assumption is not made, and the study has many censored observations, estimations obtained from the Kaplan-Meier are biased and are estimated higher than its real amount. But Weighted Kaplan-Meier decreases bias of survival probabilities by providing appropriate weights and presents more accurate understanding.
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Thayyil, Sudhin [Centre for Cardiovascular MR, UCL Institute of Child Health and Great Ormond Street Hospital for Children, London (United Kingdom)], E-mail: s.thayyil@ich.ucl.ac.uk; Schievano, Silvia [Centre for Cardiovascular MR, UCL Institute of Child Health and Great Ormond Street Hospital for Children, London (United Kingdom); Robertson, Nicola J. [EGA UCL Institute for Women' s Health, University College London (United Kingdom); Jones, Rodney [Centre for Cardiovascular MR, UCL Institute of Child Health and Great Ormond Street Hospital for Children, London (United Kingdom); Chitty, Lyn S. [EGA UCL Institute for Women' s Health, University College London (United Kingdom); Clinical Molecular Genetics Unit, Institute of Child Health, London (United Kingdom); Sebire, Neil J. [Histopathology, Great Ormond Street Hospital NHS Trust, London (United Kingdom); Taylor, Andrew M. [Centre for Cardiovascular MR, UCL Institute of Child Health and Great Ormond Street Hospital for Children, London (United Kingdom)
2009-11-15
Magnetic resonance (MR) imaging allows minimally invasive autopsy, especially when consent is declined for traditional autopsy. Estimation of individual visceral organ weights is an important component of traditional autopsy. Objective: To examine whether a semi-automated can be used for non-invasive internal organ weight measurement using post-mortem MR imaging in fetuses, newborns and children. Methods: Phase 1: In vitro scanning of 36 animal organs (heart, liver, kidneys) was performed to check the accuracy of volume reconstruction methodology. Real volumes were measured by water displacement method. Phase 2: Sixty-five whole body post-mortem MR scans were performed in fetuses (n = 30), newborns (n = 5) and children (n = 30) at 1.5 T using a 3D TSE T2-weighted sequence. These data were analysed offline using the image processing software Mimics 11.0. Results: Phase 1: Mean difference (S.D.) between estimated and actual volumes were -0.3 (1.5) ml for kidney, -0.7 (1.3) ml for heart, -1.7 (3.6) ml for liver in animal experiments. Phase 2: In fetuses, newborns and children mean differences between estimated and actual weights (S.D.) were -0.6 (4.9) g for liver, -5.1 (1.2) g for spleen, -0.3 (0.6) g for adrenals, 0.4 (1.6) g for thymus, 0.9 (2.5) g for heart, -0.7 (2.4) g for kidneys and 2.7 (14) g for lungs. Excellent co-correlation was noted for estimated and actual weights (r{sup 2} = 0.99, p < 0.001). Accuracy was lower when fetuses were less than 20 weeks or less than 300 g. Conclusion: Rapid, accurate and reproducible estimation of solid internal organ weights is feasible using the semi-automated 3D volume reconstruction method.
Carroli, Guillermo; Widmer, Mariana; Neerup Jensen, Lisa; Giordano, Daniel; Abdel Aleem, Hany; Talegawkar, Sameera A.; Benachi, Alexandra; Diemert, Anke; Tshefu Kitoto, Antoinette; Thinkhamrop, Jadsada; Lumbiganon, Pisake; Tabor, Ann; Kriplani, Alka; Gonzalez Perez, Rogelio; Hecher, Kurt; Hanson, Mark A.; Gülmezoglu, A. Metin; Platt, Lawrence D.
2017-01-01
Background Perinatal mortality and morbidity continue to be major global health challenges strongly associated with prematurity and reduced fetal growth, an issue of further interest given the mounting evidence that fetal growth in general is linked to degrees of risk of common noncommunicable diseases in adulthood. Against this background, WHO made it a high priority to provide the present fetal growth charts for estimated fetal weight (EFW) and common ultrasound biometric measurements intended for worldwide use. Methods and Findings We conducted a multinational prospective observational longitudinal study of fetal growth in low-risk singleton pregnancies of women of high or middle socioeconomic status and without known environmental constraints on fetal growth. Centers in ten countries (Argentina, Brazil, Democratic Republic of the Congo, Denmark, Egypt, France, Germany, India, Norway, and Thailand) recruited participants who had reliable information on last menstrual period and gestational age confirmed by crown–rump length measured at 8–13 wk of gestation. Participants had anthropometric and nutritional assessments and seven scheduled ultrasound examinations during pregnancy. Fifty-two participants withdrew consent, and 1,387 participated in the study. At study entry, median maternal age was 28 y (interquartile range [IQR] 25–31), median height was 162 cm (IQR 157–168), median weight was 61 kg (IQR 55–68), 58% of the women were nulliparous, and median daily caloric intake was 1,840 cal (IQR 1,487–2,222). The median pregnancy duration was 39 wk (IQR 38–40) although there were significant differences between countries, the largest difference being 12 d (95% CI 8–16). The median birthweight was 3,300 g (IQR 2,980–3,615). There were differences in birthweight between countries, e.g., India had significantly smaller neonates than the other countries, even after adjusting for gestational age. Thirty-one women had a miscarriage, and three fetuses had
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Torvid Kiserud
2017-01-01
Full Text Available Perinatal mortality and morbidity continue to be major global health challenges strongly associated with prematurity and reduced fetal growth, an issue of further interest given the mounting evidence that fetal growth in general is linked to degrees of risk of common noncommunicable diseases in adulthood. Against this background, WHO made it a high priority to provide the present fetal growth charts for estimated fetal weight (EFW and common ultrasound biometric measurements intended for worldwide use.We conducted a multinational prospective observational longitudinal study of fetal growth in low-risk singleton pregnancies of women of high or middle socioeconomic status and without known environmental constraints on fetal growth. Centers in ten countries (Argentina, Brazil, Democratic Republic of the Congo, Denmark, Egypt, France, Germany, India, Norway, and Thailand recruited participants who had reliable information on last menstrual period and gestational age confirmed by crown-rump length measured at 8-13 wk of gestation. Participants had anthropometric and nutritional assessments and seven scheduled ultrasound examinations during pregnancy. Fifty-two participants withdrew consent, and 1,387 participated in the study. At study entry, median maternal age was 28 y (interquartile range [IQR] 25-31, median height was 162 cm (IQR 157-168, median weight was 61 kg (IQR 55-68, 58% of the women were nulliparous, and median daily caloric intake was 1,840 cal (IQR 1,487-2,222. The median pregnancy duration was 39 wk (IQR 38-40 although there were significant differences between countries, the largest difference being 12 d (95% CI 8-16. The median birthweight was 3,300 g (IQR 2,980-3,615. There were differences in birthweight between countries, e.g., India had significantly smaller neonates than the other countries, even after adjusting for gestational age. Thirty-one women had a miscarriage, and three fetuses had intrauterine death. The 8,203 sets of
Kiserud, Torvid; Piaggio, Gilda; Carroli, Guillermo; Widmer, Mariana; Carvalho, José; Neerup Jensen, Lisa; Giordano, Daniel; Cecatti, José Guilherme; Abdel Aleem, Hany; Talegawkar, Sameera A; Benachi, Alexandra; Diemert, Anke; Tshefu Kitoto, Antoinette; Thinkhamrop, Jadsada; Lumbiganon, Pisake; Tabor, Ann; Kriplani, Alka; Gonzalez Perez, Rogelio; Hecher, Kurt; Hanson, Mark A; Gülmezoglu, A Metin; Platt, Lawrence D
2017-01-01
Perinatal mortality and morbidity continue to be major global health challenges strongly associated with prematurity and reduced fetal growth, an issue of further interest given the mounting evidence that fetal growth in general is linked to degrees of risk of common noncommunicable diseases in adulthood. Against this background, WHO made it a high priority to provide the present fetal growth charts for estimated fetal weight (EFW) and common ultrasound biometric measurements intended for worldwide use. We conducted a multinational prospective observational longitudinal study of fetal growth in low-risk singleton pregnancies of women of high or middle socioeconomic status and without known environmental constraints on fetal growth. Centers in ten countries (Argentina, Brazil, Democratic Republic of the Congo, Denmark, Egypt, France, Germany, India, Norway, and Thailand) recruited participants who had reliable information on last menstrual period and gestational age confirmed by crown-rump length measured at 8-13 wk of gestation. Participants had anthropometric and nutritional assessments and seven scheduled ultrasound examinations during pregnancy. Fifty-two participants withdrew consent, and 1,387 participated in the study. At study entry, median maternal age was 28 y (interquartile range [IQR] 25-31), median height was 162 cm (IQR 157-168), median weight was 61 kg (IQR 55-68), 58% of the women were nulliparous, and median daily caloric intake was 1,840 cal (IQR 1,487-2,222). The median pregnancy duration was 39 wk (IQR 38-40) although there were significant differences between countries, the largest difference being 12 d (95% CI 8-16). The median birthweight was 3,300 g (IQR 2,980-3,615). There were differences in birthweight between countries, e.g., India had significantly smaller neonates than the other countries, even after adjusting for gestational age. Thirty-one women had a miscarriage, and three fetuses had intrauterine death. The 8,203 sets of ultrasound
Phillips, Amy M; Galdamez, Amy B; Ounpraseuth, Songthip T; Magann, Everett F
2014-10-01
Delivery of a macrosomic fetus can be linked with significant maternal and perinatal morbidity. Detection of the macrosomic fetus prior to delivery could have a significant impact on reducing that morbidity. The purpose of this study was to determine the likelihood of detection of macrosomia at the time of labour and delivery admission using ultrasound. Retrospective review using the electronic medical record and delivery room logs to identify women admitted to labour and delivery with a birthweight of ≥4000 g. There were 272 macrosomic neonates delivered between January 2010 and December 2012, of which, 91 (33.46%) were identified as macrosomic by ultrasound. Using Spearman correlation, the association between the estimated fetal weight by ultrasound and birthweight was r = 0.214 (95% CI: 0.098-0.325; P = 0.0004). In bivariate analyses, only White race was significant for macrosomia detection with 59 of 149 (39.6%) identified compared with 32 of 123 (26.02%) (P = 0.020) non-White people. In the multivariate model, race remained significant. The odds of being labelled macrosomia for White people was 2.051 (95% CI: 1.188-3.542) compared with non-White people (P = 0.010). Only 33% of fetuses whose birthweight was ≥4000 g were identified by a labour and delivery ultrasound. White race was the only significant factor that increased the odds of having a correct diagnosis of macrosomia by ultrasound. © 2014 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.
Rojo-Tirado, Miguel A; Benito, Pedro J; Peinado, Ana B; Zapico, Augusto G; Calderón, Franciso J
2016-01-01
The main concern of the people who follow a weight loss program is the body weight loss, independently of the body composition. The aim of this study was to create a mathematical model able to discriminate the body weight change based on initial body composition variables. The study included 239 overweight and obese participants (18-50 years; Body Mass Index (BMI)>25 and loss, during twenty-four weeks while having 25-30% caloric restriction. Two multivariate discriminant models were performed taking into account the groups below and above the mean body weight change. The discriminant models obtained could discriminate the body weight change with a 65-70% of correct classification. BW, fat-free mass (FFM), and fat mass (FM) were shown to be the most discriminant variables for the discriminant models. People having higher FM and FFM at the beginning of an intervention will lose a greater amount of weight until the end of it.
Troxel, Andrea B; Lipsitz, Stuart R; Fitzmaurice, Garrett M; Ibrahim, Joseph G; Sinha, Debajyoti; Molenberghs, Geert
2010-06-30
For longitudinal binary data with non-monotone non-ignorably missing outcomes over time, a full likelihood approach is complicated algebraically, and with many follow-up times, maximum likelihood estimation can be computationally prohibitive. As alternatives, two pseudo-likelihood approaches have been proposed that use minimal parametric assumptions. One formulation requires specification of the marginal distributions of the outcome and missing data mechanism at each time point, but uses an 'independence working assumption,' i.e. an assumption that observations are independent over time. Another method avoids having to estimate the missing data mechanism by formulating a 'protective estimator.' In simulations, these two estimators can be very inefficient, both for estimating time trends in the first case and for estimating both time-varying and time-stationary effects in the second. In this paper, we propose the use of the optimal weighted combination of these two estimators, and in simulations we show that the optimal weighted combination can be much more efficient than either estimator alone. Finally, the proposed method is used to analyze data from two longitudinal clinical trials of HIV-infected patients. (c) 2010 John Wiley & Sons, Ltd.
Laban, Mohamed; Alanwar, Ahmed A; Etman, Mohamed K; Elsokkary, Mohammed S; Elkotb, Ahmed M; Hasanien, Ahmad S; KhalafAllah, Ali E; Noah, Nancy M
2017-07-27
This study aimed to evaluate accuracy of five-dimensional long bones (5D LB) compared to two-dimensional ultrasound (2DUS) biometry to predict fetal weight among normal term women. Fifty six normal term women were recruited at Ain Shams Maternity Hospital, Egypt from 14 May to 30 November 2015. Fetal weight was estimated by Hadlock's IV formula using 2DUS and 5D LB. Estimated fetal weights (EFW) by 2DUS and 5D LB were compared with actual birth weights (ABW). Mean femur length (FL) was 7.07 ± 0.73 cm and 6.74 ± 0.67 cm by 2DUS and 5D LB (p = .02). EFW was 3309.86 ± 463.06 g by 2DUS and 3205.46 ± 447.85 g by 5D LB (p = .25). No statistical difference was observed between ABW and EFW by 2DUS (p = .7) or 5D LB (p = .45). Positive correlation was found between EFW by 2DUS, 5D LB, and ABW (r = 0.67 and 0.7; p ABW (p = .15). 2DUS and 5D LB had same accuracy for fetal weight estimation at normal term pregnancy.
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Rieman, Bruce E.
1986-03-01
We made preliminary estimates of the loss of juvenile salmonids to predation by walleye, Stizostedion v. vitreum, and northern squawfish, Ptychocheilus oregonensis, in John Day Reservoir in 1984 and 1985 using estimates of predator abundance and daily prey consumption rates. Preliminary estimates may be biased and may be adjusted as much as 30%, but indications are that predation could account for the majority of unexplained loss of juvenile salmonids in John Day Reservoir. Total loss was estimated at 4.1 million in 1984 and 3.3 million in 1985. Northern squawfish consumed 76% and 92% of these totals, respectively. The majority of loss occurred in mid reservoir areas, but loss in a small area, the boat-restricted zone immediately below McNary Dam, was disproportionately large. Peaks in loss in May and July corresponded with peaks in availability of salmonids. Estimated mortality from predation for April through June in 1984 and 1985 was 9% and 7% respectively, for chinook salmon, Oncorhynchus tshawytscha, and 10% and 15% for steelhead, Salmogairdneri. Mortality was variable with time but tended to increase over the period of migration. Mortality of chinook was estimated at 26% to 55% during July and August. A model of predation in John Day Reservoir is outlined. The model includes a predation submodel that can calculate loss from predator number and consumption rate; a population submodel that can relate predator abundance and population structure to recruitment, exploitation, natural mortality and growth; and a distribution submodel that can apportion predators among areas of the reservoir over time. Applications of the model are discussed for projecting expected changes in predation over time and identifying management alternatives that might limit the impact of predation.
Directory of Open Access Journals (Sweden)
Francesca M. Sarti
2015-07-01
Full Text Available The Appenninica breed is an Italian meat sheep; the rams are approved according to a phenotypic index that is based on an average daily gain at performance test. The 8546 live weights of 1930 Appenninica male lambs tested in the performance station of the ASSONAPA (National Sheep Breeders Association, Italy from 1986 to 2010 showed a great variability in age at weighing and in number of records by year. The goal of the study is to verify the feasibility of the estimation of a genetic index for weight in the Appenninica sheep by a mixed model, and to explore the use of random regression to avoid the corrections for weighing at different ages. The heritability and repeatability (mean±SE of the average live weight were 0.27±0.04 and 0.54±0.08 respectively; the heritabilities of weights recorded at different weighing days ranged from 0.27 to 0.58, while the heritabilities of weights at different ages showed a narrower variability (0.29÷0.41. The estimates of live weight heritability by random regressions ranged between 0.34 at 123 d of age and 0.52 at 411 d. The results proved that the random regression model is the most adequate to analyse the data of Appenninica breed.
Jensen, Bente R; Hovgaard-Hansen, Line; Cappelen, Katrine L
2016-08-01
Running on a lower-body positive-pressure (LBPP) treadmill allows effects of weight support on leg muscle activation to be assessed systematically, and has the potential to facilitate rehabilitation and prevent overloading. The aim was to study the effect of running with weight support on leg muscle activation and to estimate relative knee and ankle joint forces. Runners performed 6-min running sessions at 2.22 m/s and 3.33 m/s, at 100%, 80%, 60%, 40%, and 20% body weight (BW). Surface electromyography, ground reaction force, and running characteristics were measured. Relative knee and ankle joint forces were estimated. Leg muscles responded differently to unweighting during running, reflecting different relative contribution to propulsion and antigravity forces. At 20% BW, knee extensor EMGpeak decreased to 22% at 2.22 m/s and 28% at 3.33 m/s of 100% BW values. Plantar flexors decreased to 52% and 58% at 20% BW, while activity of biceps femoris muscle remained unchanged. Unweighting with LBPP reduced estimated joint force significantly although less than proportional to the degree of weight support (ankle). It was concluded that leg muscle activation adapted to the new biomechanical environment, and the effect of unweighting on estimated knee force was more pronounced than on ankle force.
Gibson, Kelly S; Stetzer, Bradley; Catalano, Patrick M; Myers, Stephen A
2016-06-01
To compare the accuracy of 2-dimensional (2D) and 3-dimensional (3D) fetal measurements for prediction of birth weight Z score and neonatal adiposity (percent body fat) in the setting of suspected fetal macrosomia. We conducted a prospective observational study of term singleton pregnancies with suspected macrosomia. Patients were enrolled on admission to labor and delivery and underwent sonographic examinations. Within 48 hours of delivery, neonatal anthropometric measurements were obtained. Thirty-four neonates were included in the analysis. Mothers were very obese (mean body mass index ± SD, 39.1 ± 7.8 kg/m(2)); 56.5% were white; and 39.1% had diabetes. Neonates were 38% female and had a mean birth weight of 3940.0 ± 496.8 g, percent body fat of 18.5% ± 4.0%, and Ponderal index of 2.8 ± 0.3 g/cm(3). Mean 2D estimated fetal weight was 3973 ± 443 g; mean 3D estimated fetal weight was 3803 ± 528 g; and mean thigh volume was 102.5 ± 19.6 cm(3). Both 2D and 3D measurements accounted for about half the variance in predicted birth weight (R(2) for 2D = 0.53, 71% within 10% of birth weight; R(2) for 3D = 0.47, 65% within 10% of birth weight). Thigh volume Z score was the prenatal parameter most highly correlated with both birth weight Z score (R(2) = 0.52; r = 0.72; 95% confidence interval, 0.54-0.84; P < .001) and percent body fat (R(2) = 0.22; r = 0.47; 95% confidence interval, 0.17-0.69; P = .04). In our population of fetuses with suspected macrosomia, fractional thigh volume was the best sonographic estimate of neonatal percent body fat and birth weight Z score. Future research on prediction of neonatal weight and adiposity in macrosomic fetuses should include an estimate of fetal soft tissue given the generalized increase in body fat of these fetuses. © 2016 by the American Institute of Ultrasound in Medicine.
Ruff, Ryan Richard; Zhen, Chen
2015-05-01
Sugar-sweetened beverages (SSBs) contribute to weight gain and increase the risk of obesity. In this article, we determine the effects of an innovative SSB tax on weight and obesity in New York City adults. Dynamic weight loss models were used to estimate the effects of an expected 5800-calorie reduction resulting from an SSB tax on weight and obesity. Baseline data were derived from the New York City Community Health Survey. One, five, and 10-year simulations of weight loss were performed. Calorie reductions resulted in a per-person weight loss of 0.46 kg in year 1 and 0.92 kg in year 10. A total of 5,531,059 kg was expected to be lost over 10 years when weighted to the full New York City adult population. Approximately 50% of overall bodyweight loss occurred within the first year, and 95% within 5 years. Results showed consistent but nonsignificant decreases in obesity prevalence. SSB taxes may be viable strategies to reduce obesity when combined with other interventions to maximize effects in the population. Copyright © 2015 Elsevier Inc. All rights reserved.
Al-Obaidly, Sawsan; Parrish, Jacqueline; Murphy, Kellie E; Glanc, Phyllis; Maxwell, Cynthia
2015-08-01
Objectifs : Cette étude avait pour objectif de déterminer si la présence d’un IMC maternel prégrossesse accru entraînait une baisse de la précision de l’échographie pour ce qui est de l’estimation du poids fœtal et de la discordance intergémellaire en matière de poids dans le cadre de grossesses gémellaires, par comparaison avec des femmes présentant un IMC normal. Méthodes : Nous avons mené une étude de cohorte rétrospective portant sur des femmes qui présentaient un IMC prégrossesse (ou aux débuts de la grossesse) connu, qui ont accouché après 28 semaines de gestation à la suite d’une grossesse gémellaire viable entre 2008 et 2011, et qui ont subi un examen échographique visant l’estimation du poids fœtal dans les deux semaines ayant précédé l’accouchement. Le poids fœtal estimé (PFE) par échographie a été comparé au poids réel de chacun des jumeaux, puis la discordance intergémellaire en matière de poids (définie comme une différence de poids entre les jumeaux de plus de 25 %) a été stratifiée en fonction de l’IMC de la patiente. Nous avons cherché à déterminer si le PFE et la discordance intergémellaire en matière de poids avaient été affectés lorsque l’accouchement était survenu de 8 à 14 jours à la suite de l’échographie, par comparaison avec un accouchement étant survenu dans les sept jours de la tenue de l’échographie. Résultats : Nous avons pu identifier, au total, 300 grossesses gémellaires pour lesquelles l’IMC maternel prégrossesse était connu : 179 femmes présentaient une insuffisance pondérale ou un poids normal (IMC grossesse gémellaire, l’estimation du poids fœtal par échographie semble être plus fiable lorsqu’elle est menée peu avant l’accouchement.
Institute of Scientific and Technical Information of China (English)
ZHANG Xuanze; ZHENG Xiaogu; YANG Chi; LUO San
2013-01-01
A new static microwave sounding unit (MSU) channel 4 weighting function is obtained from using Coupled Model Inter-comparison Project,Phase 5 (CMIP5) historical multimodel simulations as inputs into the fast Radiative Transfer Model for TOVS (RTTOV vl0).For the same CMIP5 model simulations,it is demonstrated that the computed MSU channel 4 brightness temperature (T4) trends in the lower stratosphere over both the globe and the tropics using the proposed weighting function are equivalent to those calculated by RTTOV,but show more cooling than those computed using the traditional UAH (University of Alabama at Huntsville) or RSS (Remote Sensing Systems in Santa Rosa,California) static weighting functions.The new static weighting function not only reduces the computational cost,but also reveals reasons why trends using a radiative transfer model are different from those using a traditional static weighting function.This study also shows that CMIP5 model simulated T4 trends using the traditional UAH or RSS static weighting functions show less cooling than satellite observations over the globe and the tropics.Although not completely removed,this difference can be reduced using the proposed weighting function to some extent,especially over the tropics.This work aims to explore the reasons for the trend differences and to see to what extent they are related to the inaccurate weighting functions.This would also help distinguish other sources for trend errors and thus better understand the climate change in the lower stratosphere.
Coplen, T.B.; Peiser, H.S.
1998-01-01
International commissions and national committees for atomic weights (mean relative atomic masses) have recommended regularly updated, best values for these atomic weights as applicable to terrestrial sources of the chemical elements. Presented here is a historically complete listing starting with the values in F. W. Clarke's 1882 recalculation, followed by the recommended values in the annual reports of the American Chemical Society's Atomic Weights Commission. From 1903, an International Commission published such reports and its values (scaled to an atomic weight of 16 for oxygen) are here used in preference to those of national committees of Britain, Germany, Spain, Switzerland, and the U.S.A. We have, however, made scaling adjustments from Ar(16O) to Ar(12C) where not negligible. From 1920, this International Commission constituted itself under the International Union of Pure and Applied Chemistry (IUPAC). Since then, IUPAC has published reports (mostly biennially) listing the recommended atomic weights, which are reproduced here. Since 1979, these values have been called the "standard atomic weights" and, since 1969, all values have been published, with their estimated uncertainties. Few of the earlier values were published with uncertainties. Nevertheless, we assessed such uncertainties on the basis of our understanding of the likely contemporary judgement of the values' reliability. While neglecting remaining uncertainties of 1997 values, we derive "differences" and a retrospective index of reliability of atomic-weight values in relation to assessments of uncertainties at the time of their publication. A striking improvement in reliability appears to have been achieved since the commissions have imposed upon themselves the rule of recording estimated uncertainties from all recognized sources of error.
Directory of Open Access Journals (Sweden)
Dan Laurentiu STOICA
2013-02-01
Full Text Available The present scientific approach proposes a preliminary study on habitat suitability and factors’ influence using the herpetological indicator Vipera ursinii moldavica and is intended to depict well adapted preservation measures for the Ponto-Sarmatic ecosystems in the context of increased human pressure. The primary goal is to establish an impact hierarchy for the controlling factors. The study incorporates various natural and human related factors via correspondence analysis in order to mark out for the most influential ones. The goal is to enhance understanding of variables’ contribution to the process and find appropriate intervention measures as far as the Natura 2000 Management Plans are concerned
Directory of Open Access Journals (Sweden)
Olaniyi Alaba Olopade
2015-07-01
Full Text Available This study was carried out to determine and compare the proximate composition and length weight relationship of C. gariepinus from two culture systems (earthen and concrete ponds. The fish samples were collected from three fish farms with same cultural condition in different areas of Obio-akpor Local Government Area of Rivers State, Nigeria. Result on the length- weight relationship revealed that C.gariepinus reared in concrete tank had a total length of 15.50- 49.00cm with a mean of 32.71cm and weight of 150-625g, while total length of C. gariepinus reared in the earthen pond ranged from 19.90-58.0cm with a mean of 39.8cm and weight of 195-825g. The T- test shows that the total length of earthen pond were significantly higher than the concrete tank and the weight in the earthen pond was significantly higher than the concrete tank. Parameters of proximate composition analysed were moisture, protein, lipid, carbohydrate, ash and fiber from the fish flesh. Protein content showed a significantly higher in the earthen ponds than the concrete tanks. Ash contents varied from 1.5±1.66-7.4±0.67% in the concrete tanks and were significantly higher than the earthen ponds which ranged from 3.1±0.94-4.5±2.11%. Lipid was significantly higher in earthen ponds than concrete tanks. Generally, the two culture systems have a significant influence on length–weight relationship and nutritional value of C. gariepinus. However, C. gariepinus reared in concrete tank had a heavier body weight than earthen pond and also C. gariepinus reared in earthen pond had highest nutritive values than the concrete tank.
Institute of Scientific and Technical Information of China (English)
孙珊珊; 陶剑
2008-01-01
The Monte Carlo study evaluates the relative accuracy of Warm's (1989) weighted likelihood estimate (WLE) compared to the maximum likelihood estimate (MLE) using the nominal response model. And the results indicate that WLE was more accurate than MLE.
Energy Technology Data Exchange (ETDEWEB)
Zhou, Ping; Lv, Youbin; Wang, Hong; Chai, Tianyou
2017-09-01
Optimal operation of a practical blast furnace (BF) ironmaking process depends largely on a good measurement of molten iron quality (MIQ) indices. However, measuring the MIQ online is not feasible using the available techniques. In this paper, a novel data-driven robust modeling is proposed for online estimation of MIQ using improved random vector functional-link networks (RVFLNs). Since the output weights of traditional RVFLNs are obtained by the least squares approach, a robustness problem may occur when the training dataset is contaminated with outliers. This affects the modeling accuracy of RVFLNs. To solve this problem, a Cauchy distribution weighted M-estimation based robust RFVLNs is proposed. Since the weights of different outlier data are properly determined by the Cauchy distribution, their corresponding contribution on modeling can be properly distinguished. Thus robust and better modeling results can be achieved. Moreover, given that the BF is a complex nonlinear system with numerous coupling variables, the data-driven canonical correlation analysis is employed to identify the most influential components from multitudinous factors that affect the MIQ indices to reduce the model dimension. Finally, experiments using industrial data and comparative studies have demonstrated that the obtained model produces a better modeling and estimating accuracy and stronger robustness than other modeling methods.
Reported maternal education is an important predictor of pregnancy outcomes. Like income, it is believed to allow women to locate in more favorable conditions than less educated or affluent peers. We examine the effect of reported educational attainment on term birth weight (birt...
Förster, Alex; Mürle, Bettina; Böhme, Johannes; Al-Zghloul, Mansour; Kerl, Hans U; Wenz, Holger; Groden, Christoph
2016-10-01
Although lacunar infarction accounts for approximately 25% of ischemic strokes, collateral blood flow through anastomoses is not well evaluated in lacunar infarction. In 111 lacunar infarction patients, we analyzed diffusion-weighted images, perfusion-weighted images, and blood flow on dynamic four-dimensional angiograms generated by use of Signal Processing In NMR-Software. Blood flow was classified as absent (type 1), from periphery to center (type 2), from center to periphery (type 3), and combination of type 2 and 3 (type 4). On diffusion-weighted images, lacunar infarction was found in the basal ganglia (11.7%), internal capsule (24.3%), corona radiata (30.6%), thalamus (24.3%), and brainstem (9.0%). In 58 (52.2%) patients, perfusion-weighted image showed a circumscribed hypoperfusion, in one (0.9%) a circumscribed hyperperfusion, whereas the remainder was normal. In 36 (62.1%) patients, a larger perfusion deficit (>7 mm) was observed. In these, blood flow was classified type 1 in four (11.1%), 2 in 17 (47.2%), 3 in 9 (25.0%), and 4 in six (16.7%) patients. Patients with lacunar infarction in the posterior circulation more often demonstrated blood flow type 2 and less often type 3 (p = 0.01). Detailed examination and graduation of blood flow in lacunar infarction by use of dynamic four-dimensional angiograms is feasible and may serve for a better characterization of this stroke subtype.
Reported maternal education is an important predictor of pregnancy outcomes. Like income, it is believed to allow women to locate in more favorable conditions than less educated or affluent peers. We examine the effect of reported educational attainment on term birth weight (birt...
Li, Shunchong; Chen, Xingyu; Sheng, Xinjun; Zhu, Xiangyang
2013-01-01
Most of current myoelectric prostheses are using sequential and on-off control strategy within pattern classification framework, which is of robustness. But it is not a natural neuromuscular control scheme. On the other hand, there are two difficulties to control the prosthesis proportionally and simultaneously. First, human hand is high dimensional with more than 20 degrees-of-freedom (DOFs); Second, extracting such control information from EMG is hard due to signal crosstalk and noises. This paper is aimed at proposing a new method for proportional and simultaneous myoelectric control, taking advantage of synergy concept. The hand motion and corresponding forearm EMG signals were collected simultaneously. Principal component analysis (PCA) is used to reduce hand motion dimension. And support vector regression (SVR) is adopted to build the connection between hand posture and EMG. Offline analysis validated the effectiveness of this method, and preliminary and positive results have been obtained.
多阶段抽样调查资料的加权估计法%Weighted estimation methods for multistage sampling survey data
Institute of Scientific and Technical Information of China (English)
侯晓艳; 魏永越; 陈峰
2009-01-01
多阶段抽样技术广泛应用于流行病学现况调查中,但针对其所得资料的统计分析方法往往选择不当.文中介绍一种用于多阶段抽样调查资料的统计分析方法--加权估计法,以推广针对此类资料的恰当的分析方法.在介绍加权估计法基本原理的基础上通过两个二阶段分层整群抽样的实际调查资料实现这种算法.加权估计法可以校正由多阶段抽样导致的三种效应:群效应、分层效应、不等概率性,给出无偏点估计和比较客观的误差估计,并作出正确的统计推断.%Multistage sampling techniques are widely applied in the cross-sectional study of epidemiology, while methods based on independent assumption are still used to analyze such complex survey data. This paper aims to introduce the application of weighted estimation methods for the complex survey data. A brief overview of basic theory is described, and then a practical analysis is illustrated to apply to the weighted estimation algorithm in a stratified two-stage clustered sampling data. For multistage sampling survey data, weighted estimation method can be used to obtain unbiased point estimation and more reasonable variance estimation, and so make proper statistical inference by correcting the clustering, stratification and unequal probability effects.
Energy Technology Data Exchange (ETDEWEB)
Werner, Rene; Ehrhardt, Jan; Schmidt-Richberg, Alexander; Handels, Heinz [Luebeck Univ. (Germany). Inst. of Medical Informatics; Albers, Dirk; Petersen, Cordula; Cremers, Florian [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Radiotherapy and Radio-Oncology; Frenzel, Thorsten [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Health Care Center
2012-07-01
Purpose: Breathing-induced motion effects on dose distributions in radiotherapy can be analyzed using 4D CT image sequences and registration-based dose accumulation techniques. Often simplifying assumptions are made during accumulation. In this paper, we study the dosimetric impact of two aspects which may be especially critical for IMRT treatment: the weighting scheme for the dose contributions of IMRT segments at different breathing phases and the temporal resolution of 4D CT images applied for dose accumulation. Methods: Based on a continuous problem formulation a patient- and plan-specific scheme for weighting segment dose contributions at different breathing phases is derived for use in step- and -shoot IMRT dose accumulation. Using 4D CT data sets and treatment plans for 5 lung tumor patients, dosimetric motion effects as estimated by the derived scheme are compared to effects resulting from a common equal weighting approach. Effects of reducing the temporal image resolution are evaluated for the same patients and both weighting schemes. Results: The equal weighting approach underestimates dosimetric motion effects when considering single treatment fractions. Especially interplay effects (relative misplacement of segments due to respiratory tumor motion) for IMRT segments with only a few monitor units are insufficiently represented (local point differences > 25% of the prescribed dose for larger tumor motion). The effects, however, tend to be averaged out over the entire treatment course. Regarding temporal image resolution, estimated motion effects in terms of measures of the CTV dose coverage are barely affected (in comparison to the full resolution) when using only half of the original resolution and equal weighting. In contrast, occurence and impact of interplay effects are poorly captured for some cases (large tumor motion, undersized PTV margin) for a resolution of 10/14 phases and the more accurate patient- and plan-specific dose accumulation scheme
Energy Technology Data Exchange (ETDEWEB)
Gondouin, M.
1991-10-31
The West Sak (Upper Cretaceous) sands, overlaying the Kuparuk field, would rank among the largest known oil fields in the US, but technical difficulties have so far prevented its commercial exploitation. Steam injection is the most successful and the most commonly-used method of heavy oil recovery, but its application to the West Sak presents major problems. Such difficulties may be overcome by using a novel approach, in which steam is generated downhole in a catalytic Methanator, from Syngas made at the surface from endothermic reactions (Table 1). The Methanator effluent, containing steam and soluble gases resulting from exothermic reactions (Table 1), is cyclically injected into the reservoir by means of a horizontal drainhole while hot produced fluids flow form a second drainhole into a central production tubing. The downhole reactor feed and BFW flow downward to two concentric tubings. The large-diameter casing required to house the downhole reactor assembly is filled above it with Arctic Pack mud, or crude oil, to further reduce heat leaks. A quantitative analysis of this production scheme for the West Sak required a preliminary engineering of the downhole and surface facilities and a tentative forecast of well production rates. The results, based on published information on the West Sak, have been used to estimate the cost of these facilities, per daily barrel of oil produced. A preliminary economic analysis and conclusions are presented together with an outline of future work. Economic and regulatory conditions which would make this approach viable are discussed. 28 figs.
DEFF Research Database (Denmark)
Ticconi, F.; Fredenslund Levinsen, Joanna; Khvorostovsky, K.
2013-01-01
This work presents the first results of a research activity aiming to compare estimates of Surface Elevation Changes (SEC) over the Jakobshavn Isbræ basin (Greenland) using different repeat altimetry techniques and different sensors (laser vs. radar altimetry). The goal of this comparison is the ...
Lin, Jin-Ding; Lin, Lan-Ping; Hsieh, Molly; Lin, Pei-Ying
2010-01-01
The present study aimed to describe the kidney function profile--serum creatinine and estimated glomerular filtration rate (eGFR), and to examine the relationships of predisposing factors to abnormal serum creatinine in people with intellectual disabilities (ID). Data were collected by a cross-sectional study of 827 aged 15-18 years adolescents…
Directory of Open Access Journals (Sweden)
Maria Cesarina Abete
2013-04-01
Full Text Available Lifting of the ban on the use of processed animal proteins (PAPs from non-ruminants in non-ruminant feed is in the wind, avoiding intraspecies recycling. Discrimination of species will be performed through polymerase chain reaction (PCR, which is at a moment a merely qualitative method. Nevertheless, quantification of PAPs in feed is needed. The aim of this study was to approach the quantitative determination of PAPs in feed through Real Time (RT-PCR technique; three different protocols picked up from the literature were tested. Three different kind of matrices were examined: pure animal meals (bovine, chicken and pork; one feed sample certified by the European reference laboratory on animal proteins (EURL AP in feed spiked with 0.1% bovine meal; and genomic DNAs from bovine, chicken and pork muscles. The limit of detection (LOD of the three protocols was set up. All the results obtained from the three protocols considered failed in the quantification process, most likely due to the uncertain copy numbers of the analytical targets chosen. This preliminary study will allow us to address further investigations, with the purpose of developing a RT-PCR quantitative method.
Focazio, Michael J.; Plummer, L. Neil; Bohlke, John K.; Busenberg, Eurybiades; Bachman, L. Joseph; Powars, David S.
1998-01-01
Knowledge of the residence times of the ground-water systems in Chesapeake Bay watershed helps resource managers anticipate potential delays between implementation of land-management practices and any improve-ments in river and estuary water quality. This report presents preliminary estimates of ground-water residence times and apparent ages of water in the shallow aquifers of the Chesapeake Bay watershed. A simple reservoir model, published data, and analyses of spring water were used to estimate residence times and apparent ages of ground-water discharge. Ranges of aquifer hydraulic characteristics throughout the Bay watershed were derived from published literature and were used to estimate ground-water residence times on the basis of a simple reservoir model. Simple combinations of rock type and physiographic province were used to delineate hydrogeomorphic regions (HGMR?s) for the study area. The HGMR?s are used to facilitate organization and display of the data and analyses. Illustrations depicting the relation of aquifer characteristics and associated residence times as a continuum for each HGMR were developed. In this way, the natural variation of aquifer characteristics can be seen graphically by use of data from selected representative studies. Water samples collected in September and November 1996, from 46 springs throughout the watershed were analyzed for chlorofluorocarbons (CFC?s) to estimate the apparent age of ground water. For comparison purposes, apparent ages of water from springs were calculated assuming piston flow. Additi-onal data are given to estimate apparent ages assuming an exponential distribution of ages in spring discharge. Additionally, results from previous studies of CFC-dating of ground water from other springs and wells in the watershed were compiled. The CFC data, and the data on major ions, nutrients, and nitrogen isotopes in the water collected from the 46 springs are included in this report. The apparent ages of water
基于最大似然估计的加权质心定位算法%Weighted Centroid Localization Algorithm Based on Maximum Likelihood Estimation
Institute of Scientific and Technical Information of China (English)
卢先领; 夏文瑞
2016-01-01
In solving the problem of localizing nodes in a wireless sensor network,we propose a weighted centroid localization algorithm based on maximum likelihood estimation,with the specific goal of solving the problems of big received signal strength indication (RSSI)ranging error and low accuracy of the centroid localization algorithm.Firstly,the maximum likelihood estimation between the estimated distance and the actual distance is calculated as weights.Then,a parameter k is introduced to optimize the weights between the anchor nodes and the unknown nodes in the weight model.Finally,the locations of the unknown nodes are calculated and modified by using the proposed algorithm.The simulation results show that the weighted centroid algorithm based on the maximum likelihood estimation has the features of high localization accuracy and low cost,and has better performance compared with the inverse distance-based algorithm and the inverse RSSI-based algo-rithm.Hence,the proposed algorithm is more suitable for the indoor localization of large areas.%为解决无线传感器网络中节点自身定位问题，针对接收信号强度指示（received signal strength indication，RSSI）测距误差大和质心定位算法精度低的问题，提出一种基于最大似然估计的加权质心定位算法。首先通过计算将估计距离与实际距离之间的最大似然估计值作为权值，然后在权值模型中，引进一个参数k优化未知节点周围锚节点分布，最后计算出未知节点的位置并加以修正。仿真结果表明，基于最大似然估计的加权质心算法具有定位精度高和成本低的特点，优于基于距离倒数的质心加权和基于RSSI倒数的质心加权算法，适用于大面积的室内定位。
Energy Technology Data Exchange (ETDEWEB)
Ludewig, H.; Catalan-Lasheras, N.; Simos, N.; Walker, J.; Mallen, A.; Wei, J.; Todosow, M.
2000-06-30
The highest doses to components in the SNS ring are expected to be to those located in the collimation straight section. In this paper the authors present estimated doses to magnets and cable located between collimators. In addition the buildup of relatively long half-life radioactive isotopes is estimated, following machine operation and shutdown. Finally, the potential dose to operators approaching the machine following operation and shutdown for four hours is made. The results indicate that selected components might require replacement after several years of full power operation. In addition, the reflection of gamma-rays from the tunnel walls contribute a non-negligible amount to the dose of an operator in the tunnel following machine shutdown.
Institute of Scientific and Technical Information of China (English)
Xijuan; YANG; Shijun; ZHANG
2014-01-01
Based on the survey data about clam breeding farmers in Hongdao Town in August 2011,this paper analyzes the production and operation of typical clam breeding pattern,and estimates the costs and benefits. Through the analysis of operation conditions and economic conditions of Hongdao clam breeding,this paper aims to explore a more reasonable and effective breeding pattern so as to reduce breeding costs and market risks,and increase breeding farmers’ income.
Gawel, Malgorzata; Kostera-Pruszczyk, Anna; Lusakowska, Anna; Jedrzejowska, Maria; Ryniewicz, Barbara; Lipowska, Marta; Gawel, Damian; Kaminska, Anna
2015-03-01
Quantitative EMG reflects denervation of muscles after lower motor neuron degeneration in spinal muscular atrophy (SMA) but does not reflect actual motor unit loss. The aim of our study was to assess the value of the multipoint incremental motor unit number estimation (MUNE) method in the modification by Shefner in estimating motor unit loss in SMA. The number of motor units, the mean amplitude of an average surface-detected single motor unit potential (SMUP), and the amplitude of compound motor action potentials (CMAP) were estimated in 14 children with SMA in the abductor pollicis brevis (ABP). Significant differences in MUNE values and SMUP and CMAP amplitude were found between the SMA and control groups (P < 0.0001). MUNE values correlated with Hammersmith Functional Motor Scale (HFMS) scores (P < 0.05). Increased SMUP amplitude values correlated with decreased HFMS scores (P < 0.05). The study confirms that MUNE method in the modification by Shefner is a useful tool reflecting motor unit loss in SMA, and it is easy to perform and well tolerated. MUNE and SMUP amplitude seemed to be sensitive parameters reflecting motor dysfunction in SMA but a longitudinal study in a larger number of subjects is needed.
Rai, Arpita; Acharya, Ashith B.; Naikmasur, Venkatesh G.
2016-01-01
Background: Age estimation of living or deceased individuals is an important aspect of forensic sciences. Conventionally, pulp-to-tooth area ratio (PTR) measured from periapical radiographs have been utilized as a nondestructive method of age estimation. Cone-beam computed tomography (CBCT) is a new method to acquire three-dimensional images of the teeth in living individuals. Aims: The present study investigated age estimation based on PTR of the maxillary canines measured in three planes obtained from CBCT image data. Settings and Design: Sixty subjects aged 20–85 years were included in the study. Materials and Methods: For each tooth, mid-sagittal, mid-coronal, and three axial sections—cementoenamel junction (CEJ), one-fourth root level from CEJ, and mid-root—were assessed. PTR was calculated using AutoCAD software after outlining the pulp and tooth. Statistical Analysis Used: All statistical analyses were performed using an SPSS 17.0 software program. Results and Conclusions: Linear regression analysis showed that only PTR in axial plane at CEJ had significant age correlation (r = 0.32; P < 0.05). This is probably because of clearer demarcation of pulp and tooth outline at this level. PMID:28123269
Wheeler, Russell L.; Cramer, Chris H.
2000-01-01
We estimate site amplification at the location of a proposed bridge near Charleston, South Carolina. Model calculations indicate that amplification at periods of 1 s and longer is likely to be strongly influenced by the effects of a large contrast in shear-wave velocity at a depth of approximately 1 km (3,000 ft). On-site borehole data, regional geological and geophysical information, and data from a geologically similar setting near Memphis, Tennessee allowed us to estimate profiles of shear-wave velocity, shear-wave attenuation, and density from ground level down to metamorphic and igneous rocks that are approximately 3 km (9,500 ft) beneath the site. We modeled amplifications that would be produced at the surface and at the top and bottom of the Cooper Marl. Amplification estimates that are based only on the shallow shear-wave structure, for example in the upper 100 m (300 ft), can severely underestimate long-period amplification at the site. Additional modeling could help determine whether new data should be collected, to resolve remaining uncertainties about likely amplification.
Moreno-Vilet, Lorena; Bostyn, Stéphane; Flores-Montaño, Jose-Luis; Camacho-Ruiz, Rosa-María
2017-12-15
Agave fructans are increasingly important in food industry and nutrition sciences as a potential ingredient of functional food, thus practical analysis tools to characterize them are needed. In view of the importance of the molecular weight on the functional properties of agave fructans, this study has the purpose to optimize a method to determine their molecular weight distribution by HPLC-SEC for industrial application. The optimization was carried out using a simplex method. The optimum conditions obtained were at column temperature of 61.7°C using tri-distilled water without salt, adjusted pH of 5.4 and a flow rate of 0.36mL/min. The exclusion range is from 1 to 49 of polymerization degree (180-7966Da). This proposed method represents an accurate and fast alternative to standard methods involving multiple-detection or hydrolysis of fructans. The industrial applications of this technique might be for quality control, study of fractionation processes and determination of purity. Copyright © 2017 Elsevier Ltd. All rights reserved.
Musaiger, Abdulrahman O; Al-Mannai, Mariam
2014-03-01
Mass media play an important role in changing body image. This study aimed to determine the role of media (magazines and television) in body weight concern among university females in five Arab countries. A total sample of 1134 female university students was selected at convenience from universities in five Arab countries: Bahrain, Egypt, Jordan, Oman and Syria. The females' ages ranged from 17 to 32. A pre-tested questionnaire was used to assess the exposure to mass media regarding weight concerns. For the variables on exposure to mass media, girls were divided into two groups: infrequently exposed and frequently exposed. In general, the females who were exposed to mass media had a greater risk of having dieted to lose weight and changing their ideas of a perfect body shape than those who were not exposed or infrequently exposed. The association of exposure to magazines with having dieted to lose weight was only significant among females in Bahrain (pbody weight concerns of females. The association of exposure to television with females' idea of a perfect body shape was only statistically significant in females in Egypt (pmedia on the body weight concern of female university students may lead these women to practise unhealthy weight control diets.
Institute of Scientific and Technical Information of China (English)
YANG Yuanxi; GAO Weiguang
2005-01-01
An integrated navigation based on the kinematic or dynamic state model and the raw measurements has the advantages of high redundancy, high reliability, as well as high ability of fault tolerance and simplicity in calculation. In order to control the influences of measurements outliers and the kinematic model errors on the integrated navigation results, a robust estimation method and an adaptive data fusion method are applied. An integrated navigation example using simulated data is performed and analyzed.
Zhang, Tianhao; Liu, Gang; Zhu, Zhongmin; Gong, Wei; Ji, Yuxi; Huang, Yusi
2016-01-01
The real-time estimation of ambient particulate matter with diameter no greater than 2.5 μm (PM2.5) is currently quite limited in China. A semi-physical geographically weighted regression (GWR) model was adopted to estimate PM2.5 mass concentrations at national scale using the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depth product fused by the Dark Target (DT) and Deep Blue (DB) algorithms, combined with meteorological parameters. The fitting results could explain over 80% of the variability in the corresponding PM2.5 mass concentrations, and the estimation tends to overestimate when measurement is low and tends to underestimate when measurement is high. Based on World Health Organization standards, results indicate that most regions in China suffered severe PM2.5 pollution during winter. Seasonal average mass concentrations of PM2.5 predicted by the model indicate that residential regions, namely Jing-Jin-Ji Region and Central China, were faced with challenge from fine particles. Moreover, estimation deviation caused primarily by the spatially uneven distribution of monitoring sites and the changes of elevation in a relatively small region has been discussed. In summary, real-time PM2.5 was estimated effectively by the satellite-based semi-physical GWR model, and the results could provide reasonable references for assessing health impacts and offer guidance on air quality management in China. PMID:27706054
Directory of Open Access Journals (Sweden)
Zohreh Abdi Moghadam
2013-01-01
Full Text Available Aims: This study was aimed to estimate the bisphenol A (BPA intake from baby bottles, considering the diversity and the standard quality of the baby bottles distributed in an Isfahan urban society. Materials and Methods: A cross-sectional study was performed in Isfahan in 2011. Baby shops ( n = 33 and drug stores ( n = 7 in four district areas were included in the study. The distribution of baby bottles was investigated regarding their brand, origin, and being labeled "BPA free." Estimation of exposure to BPA from baby bottles was made based on the national and international representative data. Results: The products marked as "BPA free" were found among the western products and limited to two of the selected areas. No "BPA free" marked baby bottle was distinguished among the Iranian made products. Of the 8% exclusively formula-fed infants, 90% may be the high consumers of BPA from polycarbonate baby bottles, with an intake of 1.5-2 μg/kg b.w./day for the moderate and 7.5-10 μg/kg b.w./day in case of worse condition. Conclusion: Considering the current globally accepted threshold daily intake (TDI for BPA, primary exposure estimation is that feeding using non-BPA-free baby bottles is not a serious health concern in Iran. Thought that threshold level of TDI is discussed to be reduced in future, improvement and revision of the national standards can be effective in reducing the exposure to BPA in Iranian infants so as to provide large margin of safety for them.
DEFF Research Database (Denmark)
Galsgaard, Bo; Lundtoft, Dennis Holm; Nikolov, Ivan Adriyanov;
2015-01-01
One of the time consuming tasks in the timber industry is the manually measurement of features of wood stacks. Such features include, but are not limited to, the number of the logs in a stack, their diameters distribution, and their volumes. Computer vision techniques have recently been used...... for solving this real-world industrial application. Such techniques are facing many challenges as the task is usually performed in outdoor, uncontrolled, environments. Furthermore, the logs can vary in texture and they can be occluded by different obstacles. These all make the segmentation of the wood logs...... about the foreand background regions of a stack image, and then use this together with a Local Circularity Measure (LCM) to modify the weights of the graph to segment the wood logs from the rest of the image. We further improve the segmentation by separating overlapping logs. These segmented wood logs...
Datta, Surjya Narayan; Kaur, Vaneet Inder; Dhawan, Asha; Jassal, Geeta
2013-01-01
Comparative study was conducted to observe the efficacy of different feeding regimes on growth of Channa punctata. Six iso- proteinous diets were prepared by using different agro industrial by-products. Maximum weight gain was recorded with diet having 66.75% rice bran, 11.50% mustard cake, 23.0% groundnut cake, 5% molasses, 1.5% vitamin-mineral mixture and 0.5% salt with specific growth rate of 0.408. The experimental fish recorded the value of exponent 'b' in the range of 2.7675 to 4.3922. The condition factor 'K' of all experimental fish was above 1.0 (1.094- 1.235) indicating robustness or well being of experimented fish.
Institute of Scientific and Technical Information of China (English)
Qiong; TANG; Gang; WU; Danni; LIANG; Yingliang; ZHANG; Mingjun; TAN
2011-01-01
Through investigating both users’and librarians’perceptions of the relative importance of the major criteria governing the selection of digital resources,we attempted to develop a criterion weight framework for a library’s selection of digital resources,which can meet both the users’requirements and the library’s goal of developing digital collections.The respective weight of each specific criterion is decided through the Analytic Hierarchy Process(AHP)Method.The findings of this study indicate that,when assigning weights to the selection criteria,it is important to consult the opinions of a wide crosssection of people,especially the views of different users.As a result,the digital resource selection system characterized by the criteria weights can reflect more comprehensively the users’requirements,and meanwhile it enables librarians’more rational selection of digital resources.
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Bart J A Mertens
Full Text Available We consider a re-analysis of the wait-and-see (control arm of a recent clinical trial on sciatica. While the original randomised trial was designed to evaluate the public policy effect of a conservative wait-and-see approach versus early surgery, we investigate the impact of surgery at the individual patient level in a re-analysis of the wait-and-see group data. Both marginal structural model re-weighted estimates as well as propensity score adjusted analyses are presented. Results indicate that patients with high propensity to receive surgery may have beneficial effects at 2 years from delayed disc surgery.
Galante, Julieta; Augustovski, Federico; Colantonio, Lisandro; Bardach, Ariel; Caporale, Joaquin; Marti, Sebastian Garcia; Kind, Paul
2011-01-01
To estimate and compare EuroQol instrument (EQ-5D) health states' values for pneumococcal and human papillomavirus (HPV) diseases in Argentina, Chile, and the United Kingdom. Twelve vignettes were designed, pilot-tested, and administered to a convenience sample in a cross-sectional design to elicit descriptive EQ-5D state data. Country-specific EQ-5D time-trade-off-based weights were used to map these descriptive health states into local country preference weights. Descriptive analysis is reported and intercountry differences for each condition were compared using repeated measures analysis of variance. Seventy-three subjects completed the survey. Pneumococcal disease-related health states mean values ranged from -0.331 (sepsis, Chile) to 0.727 (auditive sequelae, Argentina). HPV-related conditions ranged from 0.152 (cervical cancer, United Kingdom) to 0.848 (cervical intraepithelial neoplasia 1, Argentina). Chile had consistently the lowest mean values in pneumococcal states and in one HPV state, whereas those of the United Kingdom were the lowest in most HPV states. Argentina had the highest mean values in both diseases. Differences in country-specific values for each health state were statistically (P < 0.001) significant except for six health states in which differences between Chilean and United Kingdom weights were nonsignificant. Utility values for most conditions differed statistically relevantly among analyzed countries, even though the same health states' descriptive set was valued for each. These results reflect the difference in social weights among different countries, which could be attributed to either different population values or valuation study methodologies. They stress the importance of using local preference weights for context-specific decision making. Copyright © 2011 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.
Ramos, Yuddy; St-Onge, Benoît; Blanchet, Jean-Pierre; Smargiassi, Audrey
2016-06-01
Air pollution is a major environmental and health problem, especially in urban agglomerations. Estimating personal exposure to fine particulate matter (PM2.5) remains a great challenge because it requires numerous point measurements to explain the daily spatial variation in pollutant levels. Furthermore, meteorological variables have considerable effects on the dispersion and distribution of pollutants, which also depends on spatio-temporal emission patterns. In this study we developed a hybrid interpolation technique that combined the inverse distance-weighted (IDW) method with Kriging with external drift (KED), and applied it to daily PM2.5 levels observed at 10 monitoring stations. This provided us with downscaled high-resolution maps of PM2.5 for the Island of Montreal. For the KED interpolation, we used spatio-temporal daily meteorological estimates and spatial covariates as land use and vegetation density. Different KED and IDW daily estimation models for the year 2010 were developed for each of the six synoptic weather classes. These clusters were developed using principal component analysis and unsupervised hierarchical classification. The results of the interpolation models were assessed with a leave-one-station-out cross-validation. The performance of the hybrid model was better than that of the KED or the IDW alone for all six synoptic weather classes (the daily estimate for R(2) was 0.66-0.93 and for root mean square error (RMSE) 2.54-1.89 μg/m(3)).
Institute of Scientific and Technical Information of China (English)
WANG Gaili; LIU Liping; DING Yuanyuan
2012-01-01
The errors in radar quantitative precipitation estimations consist not only of systematic biases caused by random noises but also spatially nonuniform biases in radar rainfall at individual rain-gauge stations.In this study,a real-time adjustment to the radar reflectivity-rainfall rates (Z R) relationship scheme and the gauge-corrected,radar-based,estimation scheme with inverse distance weighting interpolation was developed.Based on the characteristics of the two schemes,the two-step correction technique of radar quantitative precipitation estimation is proposed.To minimize the errors between radar quantitative precipitation estimations and rain gauge observations,a real-time adjustnent to the Z-R relationship scheme is used to remove systematic bias on the time-domain.The gauge-corrected,radar-based,estination scheme is then used to eliminate non-uniform errors in space.Based on radar data and rain gauge observations near the Huaihe River,the two-step correction technique was evaluated using two heavy-precipitation events.The results show that the proposed scheme improved not only in the underestination of rainfall but also reduced the root-mean-square error and the mean relative error of radar-rain gauge pairs.
Pippin, H. G.; Woll, S. L. B.
2000-01-01
Institutions need ways to retain valuable information even as experienced individuals leave an organization. Modern electronic systems have enough capacity to retain large quantities of information that can mitigate the loss of experience. Performance information for long-term space applications is relatively scarce and specific information (typically held by a few individuals within a single project) is often rather narrowly distributed. Spacecraft operate under severe conditions and the consequences of hardware and/or system failures, in terms of cost, loss of information, and time required to replace the loss, are extreme. These risk factors place a premium on appropriate choice of materials and components for space applications. An expert system is a very cost-effective method for sharing valuable and scarce information about spacecraft performance. Boeing has an artificial intelligence software package, called the Boeing Expert System Tool (BEST), to construct and operate knowledge bases to selectively recall and distribute information about specific subjects. A specific knowledge base to evaluate the on-orbit performance of selected materials on spacecraft has been developed under contract to the NASA SEE program. The performance capabilities of the Spacecraft Materials Selector (SMS) knowledge base are described. The knowledge base is a backward-chaining, rule-based system. The user answers a sequence of questions, and the expert system provides estimates of optical and mechanical performance of selected materials under specific environmental conditions. The initial operating capability of the system will include data for Kapton, silverized Teflon, selected paints, silicone-based materials, and certain metals. For situations where a mission profile (launch date, orbital parameters, mission duration, spacecraft orientation) is not precisely defined, the knowledge base still attempts to provide qualitative observations about materials performance and likely
Gur, Ilan; Markel, Gal; Nave, Yaron; Vainshtein, Igor; Eisenkraft, Arik; Riskin, Arieh
2014-08-01
To study the diagnostic ability of RALIS (computerized mathematical algorithm and continuous monitoring device) to detect late onset sepsis among very low birth weight preterm neonates. Randomly chosen 24 very low birth weight infants with proven sepsis were compared to 22 infants without sepsis. The clinical parameters were retrospectively collected from the medical records. The ability of RALIS to detect late onset sepsis was calculated. RALIS positively identified 23 of the 24 infants with sepsis (sensitivity 95.8%). It indicated sepsis alert median 2.0 days earlier than clinical suspicion. A false positive alert was indicated in 23% (5/22) infants. The specificity, and positive and negative predictive ability of RALIS were 77.3%. 82.1% and 94.4%, respectively. RALIS may aid in the early diagnosis of late onset sepsis in very low birth weight preterm infants.
Jansen, Rob T P; Laeven, Mark; Kardol, Wim
2002-06-01
The analytical processes in clinical laboratories should be considered to be non-stationary, non-ergodic and probably non-stochastic processes. Both the process mean and the process standard deviation vary. The variation can be different at different levels of concentration. This behavior is shown in five examples of different analytical systems: alkaline phosphatase on the Hitachi 911 analyzer (Roche), vitamin B12 on the Access analyzer (Beckman), prothrombin time and activated partial thromboplastin time on the STA Compact analyzer (Roche) and PO2 on the ABL 520 analyzer (Radiometer). A model is proposed to assess the status of a process. An exponentially weighted moving average and standard deviation was used to estimate process mean and standard deviation. Process means were estimated overall and for each control level. The process standard deviation was estimated in terms of within-run standard deviation. Limits were defined in accordance with state of the art- or biological variance-derived cut-offs. The examples given are real, not simulated, data. Individual control sample results were normalized to a target value and target standard deviation. The normalized values were used in the exponentially weighted algorithm. The weighting factor was based on a process time constant, which was estimated from the period between two calibration or maintenance procedures. The proposed system was compared with Westgard rules. The Westgard rules perform well, despite the underlying presumption of ergodicity. This is mainly caused by the introduction of the starting rule of 12s, which proves essential to prevent a large number of rule violations. The probability of reporting a test result with an analytical error that exceeds the total allowable error was calculated for the proposed system as well as for the Westgard rules. The proposed method performed better. The proposed algorithm was implemented in a computer program running on computers to which the analyzers were
Directory of Open Access Journals (Sweden)
Maurizio Chioccioli
Full Text Available Dry weight biomass is an important parameter in algaculture. Direct measurement requires weighing milligram quantities of dried biomass, which is problematic for small volume systems containing few cells, such as laboratory studies and high throughput assays in microwell plates. In these cases indirect methods must be used, inducing measurement artefacts which vary in severity with the cell type and conditions employed. Here, we utilise flow cytometry pulse width data for the estimation of cell density and biomass, using Chlorella vulgaris and Chlamydomonas reinhardtii as model algae and compare it to optical density methods. Measurement of cell concentration by flow cytometry was shown to be more sensitive than optical density at 750 nm (OD750 for monitoring culture growth. However, neither cell concentration nor optical density correlates well to biomass when growth conditions vary. Compared to the growth of C. vulgaris in TAP (tris-acetate-phosphate medium, cells grown in TAP + glucose displayed a slowed cell division rate and a 2-fold increased dry biomass accumulation compared to growth without glucose. This was accompanied by increased cellular volume. Laser scattering characteristics during flow cytometry were used to estimate cell diameters and it was shown that an empirical but nonlinear relationship could be shown between flow cytometric pulse width and dry weight biomass per cell. This relationship could be linearised by the use of hypertonic conditions (1 M NaCl to dehydrate the cells, as shown by density gradient centrifugation. Flow cytometry for biomass estimation is easy to perform, sensitive and offers more comprehensive information than optical density measurements. In addition, periodic flow cytometry measurements can be used to calibrate OD750 measurements for both convenience and accuracy. This approach is particularly useful for small samples and where cellular characteristics, especially cell size, are expected to vary
Ferraz, J B; Johnson, R K
1993-04-01
Records from 2,495 litters and 14,605 Landrace and Large White pigs from two farms, but established from the same base population and run as replicated selection lines, were analyzed. Selection within herd was on estimated breeding values weighted by economic values. Animal models and REML procedures were used to estimate genetic, phenotypic, and environmental parameters for the number of pigs born alive (NBA), litter weight at 21 d (LW), average daily gain form approximately 30 to 104 kg (ADG), and backfat thickness adjusted to 104 kg (BF). Random animal genetic effects (o), permanent (NBA and LW) or litter (ADG and BF) environmental effects, maternal genetic effects (m), and the covariance between o and m were sequentially added to the model. Estimates of total heritability calculated from all data (ht2 = sigma o2 + 1/2 sigma m2 + 3/2 sigma om) ranged from .01 to .14 for NBA, from .18 to .22 for LW, from .23 to .34 for ADG, and from .40 to .50 for BF. Maternal genetic variance was from 2.4 to 3.8% of phenotypic variance in NBA, from 1.2 to 3.6% in LW, from .5 to 1.5% in ADG, and from 1.9 to 3.4% in BF. The correlation between o and m was -.07 for NBA, -.25 for LW, -.34 for ADG, and -.26 for BF. Permanent environmental effects explained from 16 to 17% of total phenotypic variation for NBA and from 1.6 to 5.3% for LW. Approximately 7% of the variation in ADG and 5% in BF was due to litter environmental effects.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abed Firoozjah
2016-07-01
Full Text Available Background Obesity is one of the important chronic diseases with high growth in worldwide and bariatric surgery is currently considered the most effective treatment for weight reduction. Objectives We aimed to analyze weight loss follow up and diabetes management in patients submitted to mini gastric bypass on use of vitamin and mineral supplementation, in the new set up center, in Mazandaran province for the first time. Methods Prospective analysis of 27 volunteers of both sexes, aged between 23 - 52 years, using laparoscopic mini gastric bypass in Sari’s Avicenna hospital, were included; personal information, anthropometric and laboratory data in the preoperative, 3, 6 and 9 months were collected. Statistical analysis was done with SPSS, 19 and using the Wilcoxon and Friedman test. Results During follow up time after 276 days mean weight decreased from 118.7 ± 23.3 to 82.9 ± 15.7, P < 0.001 BMI also changed from 45.2 ± 1.8 to 32.2 ± 1.3, P < 0.001. There was decrease in percentage of excess weight loss at month of 3, 6 and 9 were 52.1, 32.6 and 16.4 respectively. Fasting blood sugar in diabetic subjects (n = 16 decreased from 170.9 ± 84.5 to 89.8 ± 11.3, P = 0.04. Conclusions In the newly set up center similar to the older one, surgical treatment in our follow up duration was effective for reducing weight, body mass index reduction and achievement of success in biochemical markers on diabetics.
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C. V. Christova
2000-06-01
Full Text Available Global data have been widely used for seismicity and seismic hazard assessment by seismologists. In the present study we evaluate worldwide seismicity in terms of maps of maximum observed magnitude (Mmax, seismic moment (M 0 and seismic moment rate (M 0S. The data set used consists of a complete and homogeneous global catalogue of shallow (h £ 60 km earthquakes of magnitude MS ³ 5.5 for the time period 1894-1992. In order to construct maps of seismicity and seismic hazard the parameters a and b derived from the magnitude-frequency relationship were estimated by both: a the least squares, and b the maximum likelihood, methods. The values of a and b were determined considering circles centered at each grid point 1° (of a mesh 1° ´1° and of varying radius, which starts from 30 km and moves with a step of 10 km. Only a and b values which fulfill some predefined conditions were considered in the further procedure for evaluating the seismic hazard maps. The obtained worldwide M max distribution in general delineates the contours of the plate boundaries. The highest values of M max observed are along the circum-Pacific belt and in the Himalayan area. The subduction plate boundaries are characterized by the largest amount of M 0 , while areas of continental collision are next. The highest values of seismic moment rate (per 1 year and per equal area of 10 000 km 2 are found in the Southern Himalayas. The western coasts of U.S.A., Northwestern Canada and Alaska, the Indian Ocean and the eastern rift of Africa are characterized by high values of M 0 , while most of the Pacific subduction zones have lower values of seismic moment rate. Finally we analyzed the seismic hazard in South America comparing the predicted by the NUVEL1 model convergence slip rate between Nazca and South America plates with the average slip rate due to earthquakes. This consideration allows for distinguishing between zones of high and low coupling along the studied convergence
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Gabriel A. Pinilla Agudelo
2013-09-01
Full Text Available ABSTRACT A methodological proposal for estimating environmental flows in large projects approved by Agencia Nacional de Licencias Ambientales (ANLA in Colombian rivers was developed. The project is the result of an agreement between the MADS and the Universidad Nacional de Colombia, Bogotá (UNC. The proposed method begins with an evaluation of hydrological criteria,continues with a hydraulic and water quality validation, and follows with the determination of habitat integrity. This is an iterative process that compares conditions before and after the project construction and allows to obtain the magnitude of a monthly flow that, besides preserving the ecological functions of the river, guarantees the water uses downstream. Regarding to the biotic component, the proposal includes the establishment and monitoring of biotic integrity indices for four aquatic communities (periphyton, macroinvertebrates, riparian vegetation, and fish. The effects that flow reduction may produce in the medium and long term can be assessed by these indices. We present the results of applying the methodology to several projects licensed by the MADS. RESUMEN Se presenta una propuesta metodológica para estimar los caudales ambientales en grandes proyectos licenciados por la Agencia Nacional de Licencias Ambientales (ANLA de Colombia, resultado de un convenio interadministrativo suscrito entre el ahora Ministerio de Ambiente y Desarrollo Sostenible (MADS de Colombia y la Universidad Nacional de Colombia, Bogotá (UNC. El método propuesto parte de garantizar criterios hidrológicos, continúa con una validación hidráulica y de calidad del agua, sigue con la determinación de la integridad del hábitat, en un proceso iterativo que requiere evaluación para las condiciones antes y después de la construcción del proyecto y que permite establecer un caudal que, además de conservar las funciones ecológicas del río, garantiza los usos del recurso aguas abajo. Espec
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Jaqueline de Oliveira Castro
2012-02-01
Full Text Available Quail breeding is a viable alternative for animal production and due to its low investment, fast return of invested capital, use of small areas and creation of jobs has aroused much interest in Brazil. The aim of this study was to develop a model based on fuzzy set theory to predict the weight of eggs from Japanese quails. The proposed fuzzy model was based on data from field measurement experiments, as well as from literature referring to the influence of environment over the weight of eggs. To develop the fuzzy system, air dry-bulb temperature (t db, ° C and relative air humidity (RH, % were defined as input variables and trapezoidal and triangular membership functions were used, respectively. The absolute deviation between the values for observed egg weight and egg weight estimated by the fuzzy system, varied between 0.01 g and 0.32 g, and the average deviation was 0.14 g. The average error found was 2.33%, and the determination coefficient (R² was equal to 0.668. The fuzzy system developed to estimate the weight of Japanese quail eggs, based on the t db and RH provided low values for absolute deviation and percentage error, allows a realistic estimate of the weight of eggs in different environmental conditions.A cotornicultura é uma alternativa na produção animal que, pelo baixo investimento, rápido retorno do capital investido, utilização de pequenas áreas e à gereção de novos empregos, tem despertado grande interesse no Brasil. Neste trabalho, objetivou-se desenvolver um modelo baseado na teoria dos conjuntos fuzzy para a predição do peso de ovos de codornas japonesas. O modelo fuzzy proposto foi elaborado com base em dados experimentais oriundos de medições em campo, bem como da literatura, a respeito da influência do ambiente sobre o peso de ovos de codornas japonesas de postura. Para o desenvolvimento do sistema fuzzy, foram definidas, como variáveis de entrada, a temperatura de bulo seco (t bs, °C e a umidade
Bleiwas, Donald I.; Gambogi, Joseph
2013-01-01
Rare-earth elements (REEs) are contained in a wide range of products of economic and strategic importance to the Nation. The REEs may or may not represent a significant component of that product by mass, value, or volume; however, in many cases, the embedded REEs are critical for the device’s function. Domestic sources of primary supply and the manufacturing facilities to produce products are inadequate to meet U.S. requirements; therefore, a significant percentage of the supply of REEs and the products that contain them are imported to the United States. In 2011, mines in China produced roughly 97 percent of the world’s supply of REEs, and the country’s production of these elements will likely dominate global supply until at least 2020. Preliminary estimates of the types and amount of rare-earth elements, reported as oxides, in semimanufactured form and the amounts used for electric vehicle batteries, catalytic converters, computers, and other applications were developed to provide a perspective on the Nation’s use of these elements. The amount of rare-earth metals recovered from recycling, remanufacturing, and reuse is negligible when the tonnage of products that contain REEs deposited in landfills and retained in storage is considered. Under favorable market conditions, the recovery of REEs from obsolete products could potentially displace a portion of the supply from primary sources.
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Marija Podbojec
2016-02-01
Full Text Available A preliminary assessment of the capacity of regional geological storage in the western part of the Sava Depression was based on data obtained from several deep exploration wells. The Poljana Sandstones represent a regional deep sandstone body, in most parts saturated with water, with promising underground facilities for the storage of CO₂ in the study area. Poljana Sandstones (member of Kloštar-Ivanić Formation bounded between E-log markers Rνand Z' have favourable petrophysical properties and are situated at reasonable depths. According to previous investigations, at depths greater than 800 meters supercritical conditions of temperature and pressure CO₂ are achieved, which ensures easy and safe injection into storage underground facilities. For the creation of a model in Petrel software, various data was used, including the distribution of CO₂ density, porosity, effective thickness and the relative depth of sandstone. Spatial distribution of porosity was made regarding neutron porosity logs. The most important parameter in the estimate of storage capacity is effective thickness, defined by the interval between E–log markers Rν and Z’. Hence, the effective thickness was used for top and bottom surface of sandstones. Density of CO₂ was created according to their spatial distribution regarding the depth and the temperature. The capacity of CO2 storage was calculated by the volumetric method. The use of a calculated Petrel model can subsequently determine the amount of CO₂ storage in the underground facilities of the study area.
Whiting, Donald M; Tomycz, Nestor D; Bailes, Julian; de Jonge, Lilian; Lecoultre, Virgile; Wilent, Bryan; Alcindor, Dunbar; Prostko, E Richard; Cheng, Boyle C; Angle, Cynthia; Cantella, Diane; Whiting, Benjamin B; Mizes, J Scott; Finnis, Kirk W; Ravussin, Eric; Oh, Michael Y
2013-07-01
Deep brain stimulation (DBS) of the lateral hypothalamic area (LHA) has been suggested as a potential treatment for intractable obesity. The authors present the 2-year safety results as well as early efficacy and metabolic effects in 3 patients undergoing bilateral LHA DBS in the first study of this approach in humans. Three patients meeting strict criteria for intractable obesity, including failed bariatric surgery, underwent bilateral implantation of LHA DBS electrodes as part of an institutional review board- and FDA-approved pilot study. The primary focus of the study was safety; however, the authors also received approval to collect data on early efficacy including weight change and energy metabolism. No serious adverse effects, including detrimental psychological consequences, were observed with continuous LHA DBS after a mean follow-up of 35 months (range 30-39 months). Three-dimensional nonlinear transformation of postoperative imaging superimposed onto brain atlas anatomy was used to confirm and study DBS contact proximity to the LHA. No significant weight loss trends were seen when DBS was programmed using standard settings derived from movement disorder DBS surgery. However, promising weight loss trends have been observed when monopolar DBS stimulation has been applied via specific contacts found to increase the resting metabolic rate measured in a respiratory chamber. Deep brain stimulation of the LHA may be applied safely to humans with intractable obesity. Early evidence for some weight loss under metabolically optimized settings provides the first "proof of principle" for this novel antiobesity strategy. A larger follow-up study focused on efficacy along with a more rigorous metabolic analysis is planned to further explore the benefits and therapeutic mechanism behind this investigational therapy.
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Salvatore Francesco Carbone
2014-01-01
Full Text Available Objectives. To assess the diagnostic performance of diffusion-weighted MR imaging (DWI in patients affected by prostatic fossa (PF relapse after radical prostatectomy (RP for prostatic carcinoma (PC. Methods. Twenty-seven patients showing a nodular lesion in the PF at T2-weighted MR imaging after RP, with diagnosis of PC relapse established by biopsy or PSA determinations, were investigated by DWI. Two readers evaluated the DWI results in consensus and the apparent diffusion coefficient (ADC of the nodules, separately; a mean value was obtained (ADCm. Results. Relapses did not significantly differ in size in respect of postsurgical benign nodules. The DWI qualitative evaluation showed sensitivity, specificity, accuracy, ppv, and npv values, respectively, of 83.3%, 88.9%, 85.2%, 93.7%, and 72.7% (100%, 87.5%, 95.6%, 93.7%, and 100%, for nodules >6 mm. The intraclass correlation coefficient (ICC for ADC evaluation between the two readers was 0.852 (95% CI 0.661–0.935; P=0.0001. The ADCm values for relapses and benign nodules were, respectively, 0.98±0.21×10−3 mm2/sec and 1.24±0.32×10−3 mm2/sec (P=0.006. Sensitivity, specificity, accuracy, ppv and npv of ADCm were, respectively, 77.8%, 88.9%, 81.8%, 93.3%, and 66.7% (93.3%, 87.5%, 85.4%, 93.3%, and 87.5% for nodules >6 mm. Conclusions. Diffusion-weighted MR imaging is a promising tool in the management of a hyperintense nodule detected by T2-weighted sequences. This might have a relevant importance in contouring radiotherapy treatment volumes.
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Yasukazu Nakanishi; Iwao Fukui; Kazunori Kihara; Hitoshi Masuda; Satoru Kawakami; Mizuaki Sakura; Yasuhisa Fujii; Kazutaka Saito; Fumitaka Koga; Masaya Ito; Junji Yonese
2012-01-01
Anthropometric measurements,e.g.,body weight (BW),body mass index (BMI),as well as serum prostate-specific antigen (PSA) and percent-free PSA (％fPSA) have been shown to have positive correlations with total prostate volume (TPV).We developed an equation and nomegram for estimating TPV,incorporating these predictors in men with benign prostatic hyperplasia (BPH).A total of 1852 men,including 1113 at Tokyo Medical and Dental University (TMDU) Hospital as a training set and 739 at Cancer Institute Hospital (CIH) as a validation set,with PSA levels of up to 20 ng ml-1,who underwent extended prostate biopsy and were proved to have BPH,were enrolled in this study.We developed an equation for continuously coded TPV and a logistic regression-based nomngram for estimating a TPV greater than 40 ml.Predictive accuracy and performance characteristics were assessed using an area under the receiver operating characteristics curve (AUC) and calibration plots.The final linear regression model indicated age,PSA,％fPSA and BW as independent predictors of continuously coded TPV.For predictions in the training set,the multiple correlation coefficient was increased from 0.38 for PSA alone to 0.60 in the final model.We developed a novel nomogram incorporating age,PSA,％fPSA and BW for estimating TPV greater than 40 ml.External validation confirmed its predictive accuracy,with AUC value of 0.764.Calibration plots showed good agreement between predicted probability and observed proportion.In conclusion,TPV can be easily estimated using these four independent predictors.
Barnes, Rachel D; Barber, Jessica A
2017-02-14
Motivational interviewing (MI) treatment for weight loss is being studied in primary care. The effect of such interventions on metabolic syndrome or binge eating disorder (BED), both highly related to excess weight, has not been examined in primary care. This study conducted secondary analyses from a randomized controlled trial to test the impact of MI for weight loss in primary care on metabolic syndrome. 74 adult participants with overweight/obesity recruited through primary care were randomized to 12weeks of either MI, an attentional control, or usual care. Participants completed measurements for metabolic syndrome at pre- and post-treatment. There were no statistically significant differences in metabolic syndrome rates at pre-, X(2)(2)=0.16, p=0.921, or post-, X(2)(2)=0.852, p=0.653 treatment. The rates in metabolic syndrome, however, decreased for MI (10.2%) and attentional control (13.8%) participants, but not for usual care. At baseline, metabolic syndrome rates did not differ significantly between participants with BED or without BED across treatments. At post-treatment, participants with BED were significantly more likely to meet criteria for metabolic syndrome than participants without BED, X(2)(1)=5.145, p=0.023, phi=0.273. Across treatments, metabolic syndrome remitted for almost a quarter of participants without BED (23.1%) but for 0% of those with BED. These preliminary results are based on a small sample and should be interpreted with caution, but they are the first to suggest that relatively low intensity MI weight loss interventions in primary care may decrease metabolic syndrome rates but not for individuals with BED.
Weiner, Eran; Mizrachi, Yossi; Fainstein, Nataly; Elyashiv, Osnat; Mevorach-Zussman, Noa; Bar, Jacob; Kovo, Michal
2017-01-01
To compare the accuracy of ultrasonographic, calculated, and clinical methods for the estimation of fetal weight (EFW) performed during active labor by residents. Parturients in active labor underwent prospectively EFW by 3 methods: ultrasonographic, clinical, and calculated (extrapolating EFW from a previous scan). Three different blinded residents evaluated each woman. Background variables were examined for their effect on the accuracy of each method. Comparison of the methods for the detection of macrosomia and small for gestational age (SGA) was also performed. Among the 405 women recruited, the rates of accuracy of ultrasonographic, clinical, and calculated EFW (within ±10%) was 72.5, 74.3, and 71.1%, respectively. The correlation coefficient between the methods and actual birth weight (ABW) were 0.702-0.611 (using 7 Hadlock formulas), 0.649, and 0.622, respectively (all p ABW. Clinical and calculated EFWs were superior for macrosomia detection, whereas ultrasonographic EFW was superior for SGA detection. © 2016 S. Karger AG, Basel.
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Holly Ockenden
2016-11-01
Full Text Available The aim of this study was to develop and validate an electronic questionnaire, the Electronic Maternal Health Survey (EMat Health Survey, related to women’s knowledge and perceptions of the current gestational weight gain guidelines (GWG, as well as pregnancy-related health behaviours. Constructs addressed within the questionnaire include self-efficacy, locus of control, perceived barriers, and facilitators of physical activity and diet, outcome expectations, social environment and health practices. Content validity was examined using an expert panel (n = 7 and pilot testing items in a small sample (n = 5 of pregnant women and recent mothers (target population. Test re-test reliability was assessed among a sample (n = 71 of the target population. Reliability scores were calculated for all constructs (r and intra-class correlation coefficients (ICC, those with a score of >0.5 were considered acceptable. The content validity of the questionnaire reflects the degree to which all relevant components of excessive GWG risk in women are included. Strong test-retest reliability was found in the current study, indicating that responses to the questionnaire were reliable in this population. The EMat Health Survey adds to the growing body of literature on maternal health and gestational weight gain by providing the first comprehensive questionnaire that can be self-administered and remotely accessed. The questionnaire can be completed in 15–25 min and collects useful data on various social determinants of health and GWG as well as associated health behaviours. This online tool may assist researchers by providing them with a platform to collect useful information in developing and tailoring interventions to better support women in achieving recommended weight gain targets in pregnancy.
Al-Hadyan, Khaled; Elewisy, Sara; Moftah, Belal; Shoukri, Mohamed; Alzahrany, Awad; Alsbeih, Ghazi
2014-12-01
In cases of public or occupational radiation overexposure and eventual radiological accidents, it is important to provide dose assessment, medical triage, diagnoses and treatment to victims. Cytogenetic bio-dosimetry based on scoring of dicentric chromosomal aberrations assay (DCA) is the "gold standard" biotechnology technique for estimating medically relevant radiation doses. Under the auspices of the National Science, Technology and Innovation Plan in Saudi Arabia, we have set up a biodosimetry laboratory and produced a national standard dose-response calibration curve for DCA, pre-required to estimate the doses received. For this, the basic cytogenetic DCA technique needed to be established. Peripheral blood lymphocytes were collected from four healthy volunteers and irradiated with radiation doses between 0 and 5 Gy of 320 keV X-rays. Then, lymphocytes were PHA stimulated, Colcemid division arrested and stained cytogenetic slides were prepared. The Metafer4 system (MetaSystem) was used for automatic and manually assisted metaphase finding and scoring of dicentric chromosomes. Results were fit to the linear-quadratic dose-effect model according to the IAEA EPR-Biodosimetry-2011 report. The resulting manually assisted dose-response calibration curve (Y = 0.0017 + 0.026 × D + 0.081 × D(2)) was in the range of those described in other populations. Although the automated scoring over-and-under estimates DCA at low (2 Gy) doses, respectively, it showed potential for use in triage mode to segregate between victims with potential risk to develop acute radiotoxicity syndromes. In conclusion, we have successfully established the first biodosimetry laboratory in the region and have produced a preliminary national dose-response calibration curve. The laboratory can now contribute to the national preparedness plan in response to eventual radiation emergencies in addition to providing information for decision makers and public health officials who assess the
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Bomba M
2015-03-01
Full Text Available Monica Bomba,1,* Anna Riva,1,* Sabrina Morzenti,2 Marco Grimaldi,3 Francesca Neri,1 Renata Nacinovich1 1Child and Adolescent Mental Health Department, San Gerardo Hospital, University of Milano-Bicocca, Monza, Italy; 2Medical Physics Department, San Gerardo Hospital, Monza, Italy; 3Department of Radiology, Humanitas Research Hospital, Milan, Italy *These authors contributed equally to this work Abstract: The recent literature on anorexia nervosa (AN suggests that functional and structural abnormalities of cortico-limbic areas might play a role in the evolution of the disease. We explored global and regional brain volumes in a cross-sectional and follow-up study on adolescents affected by AN. Eleven adolescents with AN underwent a voxel-based morphometry study at time of diagnosis and immediately after weight recovery. Data were compared to volumes carried out in eight healthy, age and sex matched controls. Subjects with AN showed increased cerebrospinal fluid volumes and decreased white and gray matter volumes, when compared to controls. Moreover, significant regional gray matter decrease in insular cortex and cerebellum was found at time of diagnosis. No regional white matter decrease was found between samples and controls. Correlations between psychological evaluation and insular volumes were explored. After weight recovery gray matter volumes normalized while reduced global white matter volumes persisted. Keywords: anorexia nervosa, adolescent, gray matter, insula, voxel-based morphometry study
Institute of Scientific and Technical Information of China (English)
Zheng-han Yang; Xiao-hua Ye; Ye Tan; Min Zhang; Ming-zhu Zhou; Jing-xia Xie; Min Chen; Cheng Zhou
2006-01-01
Objective To investigate the role of perfusion-weighted magnetic resonance imaging (MRI) in evaluation of cirrhotic liver.Methods With a 4F catheter,1% diluted carbon tetrachloride (1 ml/kg) was selectively injected into right or left hepatic artery of 12 dogs fortnightly.The half liver into which carbon tetrachloride was injected was called as study side (SS),while the other half liver without carbon tetrachloride injection was called as study control side (SCS).Conventional and perfusion-weighted MRI were performed in every 4 weeks.Via a 4F catheter,5ml gadolinium diethylentriamine pentaaceti acid (Gd-DTPA) dilution was injected into superior mesenteric artery at the 5th scan.The signal intensity-time curves of SS,SCS,and portal vein were completed in MR workstation.The maximal relative signal increase (MRSI),peak time (tp),and slope of the curves were measured.Results On conventional MR images,no abnormalities of externality and signal intensity were observed in both SS and SCS of liver at each stage.The mean tp,MRSI,and slope of intensity-time curves in normal liver were 10.56 seconds,1.01,and 10.23 arbitrary unit (au)/s,respectively.Three parameters of curves didn't show obvious change in SCS of liver at every stage.Abnormal perfusion curves occurred in SS of liver at the 12th week after the 1st injection.The abnormality of perfusion curve in SS was more and more serious as the times of injection increased.The mean tp,MRSI,and slope intensity-time curves in SS of liver were 19.45 seconds,0.43,and 3.60 au/s respectively at the 24th week.Conclusion Perfusion-weighted imaging can potentially provide information about portal perfusion of hepatic parenchyma,and to some degree,reflect the severity of cirrhosis.
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Jang, Kyung Mi; Kim, Seong Hyun; Choi, Dongil; Lee, Soon Jin; Rhim, Hyunchul; Park, Min Jung (Depts. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)), email: kshyun@skku.edu
2011-10-15
Background The use of oral contrast has been essential for the identification of a normal appendix on MR imaging during pregnancy. However, stool could be used as a positive oral contrast as it is characterized by a relatively high signal on T1-weighted imaging, and 3D T1-weighted gradient-echo (T1W-GRE) MR imaging has been used to evaluate 3 mm diameter intestines in fetuses. Purpose To evaluate the added value of 3D T1W-GRE MR imaging in combination with T2-weighted imaging (T2WI) compared to T2WI alone for evaluating the appendix during pregnancy. Material and Methods Eighteen consecutive pregnant patients who were clinically suspected of having acute appendicitis underwent appendix MR imaging which included T2WI with or without spectral presaturation attenuated inversion-recovery (SPAIR) fat suppression, and 3D T1W-GRE with SPAIR fat suppression. Two radiologists reviewed the two image sets (the T2WI set and the combined set of T2WI and 3D T1W-GRE images). Pathologic and clinical results served as the reference standard. The differences in the degree of visibility of the appendix and confidence scale for diagnosing acute appendicitis between two image sets were compared by using the paired Wilcoxon signed rank test. Results For both reviewers, the degree of visibility of the appendix using the combined T2WI and 3D T1W-GRE images was significantly higher than using T2WI alone (P < 0.01), and the confidence levels for acute appendicitis using combined T2WI and 3D T1W-GRE images were significantly different from those using T2WI alone (P < 0.01). In the 13 patients with a normal appendix, both reviewers showed improved confidence levels for appendicitis using combined T2WI and 3D T1W-GRE images than T2WI alone. Conclusion Adding 3D T1W-GRE images to T2WI is helpful for identification of the appendix, as compared to T2WI alone in pregnant women without ingestion of oral contrast material. This may improve diagnostic confidence for acute appendicitis in pregnant
You, Wei; Zang, Zengliang; Zhang, Lifeng; Li, Yi; Wang, Weiqi
2016-05-01
Taking advantage of the continuous spatial coverage, satellite-derived aerosol optical depth (AOD) products have been widely used to assess the spatial and temporal characteristics of fine particulate matter (PM2.5) on the ground and their effects on human health. However, the national-scale ground-level PM2.5 estimation is still very limited because the lack of ground PM2.5 measurements to calibrate the model in China. In this study, a national-scale geographically weighted regression (GWR) model was developed to estimate ground-level PM2.5 concentration based on satellite AODs, newly released national-wide hourly PM2.5 concentrations, and meteorological parameters. The results showed good agreements between satellite-retrieved and ground-observed PM2.5 concentration at 943 stations in China. The overall cross-validation (CV) R (2) is 0.76 and root mean squared prediction error (RMSE) is 22.26 μg/m(3) for MODIS-derived AOD. The MISR-derived AOD also exhibits comparable performance with a CV R (2) and RMSE are 0.81 and 27.46 μg/m(3), respectively. Annual PM2.5 concentrations retrieved either by MODIS or MISR AOD indicated that most of the residential community areas exceeded the new annual Chinese PM2.5 National Standard level 2. These results suggest that this approach is useful for estimating large-scale ground-level PM2.5 distributions especially for the regions without PMs monitoring sites.
A FIRST APPROXIMATION CALCULATION OF AIR CUSHION CHASSIS WEIGHT OF TRANSPORT AIRPLANE
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2016-01-01
Full Text Available This article describes a first approximation of a weighted estimate of air cushion chassis. The algorithm for calculating the weight of air cushion chassis allows not only to estimate the mass of the chassis to a first approximation, but also to conduct a preliminary analysis of the influence of various parameters of the aircraft and the chassis on the weight of the aircraft at the stage of before designing. The algorithm can be expanded to include additional design decisions, such as the transformation of the fuselage, increasing the air cushion chassis canopy due to extensions, center of gravity, etc.
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Hafeez, Rehana; Boulos, Paul [University College London Hospitals NHS Trust, Department of Surgery, London (United Kingdom); Punwani, Shonit; Halligan, Steve [University College London, Centre for Medical Imaging, London (United Kingdom); University College London Hospitals NHS Trust, Department of Specialist X-ray, Level 2 podium, London (United Kingdom); Pendse, Doug [University College London, Centre for Medical Imaging, London (United Kingdom); Bloom, Stuart [University College London Hospitals NHS Trust, Department of Gastroenterology, London (United Kingdom); Taylor, Stuart A. [University College London, Centre for Medical Imaging, London (United Kingdom); University College London Hospitals NHS Trust, Department of Specialist X-ray, Level 2 podium, London (United Kingdom)
2011-02-15
To derive an MRI score for assessing severity, therapeutic response and prognosis in acute severe inflammatory colitis. Twenty-one patients with acute severe colitis underwent colonic MRI after admission and again (n = 16) after median 5 days of treatment. Using T2-weighted images, two radiologists in consensus graded segmental haustral loss, mesenteric and mural oedema, mural thickness, and small bowel and colonic dilatation producing a total colonic inflammatory score (TCIS, range 6-95). Pre- and post-treatment TCIS were compared, and correlated with CRP, stool frequency, and number of inpatient days (therapeutic response marker). Questionnaire assessment of patient worry, satisfaction and discomfort graded 1 (bad) to 7 (good) was administered Admission TCIS correlated significantly with CRP (Kendall's tau=0.45, 95% confidence interval [CI] 0.11-0.79, p = 0.006), and stool frequency (Kendall's tau 0.39, 95% CI 0.14-0.64, p = 0.02). TCIS fell after treatment (median [22 range 15-31]) to median 20 [range 8-25], p = 0.01. Admission TCIS but not CRP or stool frequency was correlated with length of inpatient stay (Kendall's tau 0.40, 95% CI 0.11-0.69, p = 0.02). Patients reported some discomfort (median score 4) during MRI. MRI TCIS falls after therapy, correlates with existing markers of disease severity, and in comparison may better predict therapeutic response. (orig.)
... Anger Weight Management Weight Management Smoking and Weight Healthy Weight Loss Being Comfortable in Your Own Skin Your Weight Loss Expectations & Goals Healthier Lifestyle Healthier Lifestyle Physical Fitness Food & Nutrition Sleep, Stress & Relaxation Emotions & Relationships HealthyYouTXT ...
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Bladowska, Joanna, E-mail: asia.bladowska@gmail.com [Department of General Radiology, Interventional Radiology and Neuroradiology, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw (Poland); Zimny, Anna, E-mail: abernac@wp.pl [Department of General Radiology, Interventional Radiology and Neuroradiology, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw (Poland); Guziński, Maciej, E-mail: guziol@wp.pl [Department of General Radiology, Interventional Radiology and Neuroradiology, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw (Poland); Hałoń, Agnieszka, E-mail: ahalon2@gmail.com [Department of Pathomorphology and Oncological Cytology, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw (Poland); Tabakow, Paweł, E-mail: p.tabakov@wp.pl [Department of Neurosurgery, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw (Poland); Czyż, Marcin, E-mail: mt.czyz@gmail.com [Department of Neurosurgery, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw (Poland); Czapiga, Bogdan, E-mail: bogdanczapiga@op.pl [Department of Neurosurgery, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw (Poland); Jarmundowicz, Włodzimierz, E-mail: jarmund@wp.pl [Department of Neurosurgery, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw (Poland); Sąsiadek, Marek J., E-mail: marek.sasiadek@am.wroc.pl [Department of General Radiology, Interventional Radiology and Neuroradiology, Wroclaw Medical University, Borowska 213, 50-556 Wroclaw (Poland)
2013-08-15
Purpose: The most common pituitary tumors are adenomas, which however may be mimicked by other tumors that can show a very similar appearance in plain MRI. The aim of our study was to evaluate the usefulness of perfusion weighted MR imaging (PWI), including signal-intensity curves analysis in the differential diagnosis of sellar/parasellar tumors. Methods: Forty-one patients with sellar/parasellar tumors (23 macroadenomas, 10 meningiomas, 5 craniopharyngiomas, 1 intrasellar hemangioblastoma, 1 intrasellar prostate cancer metastasis, 1 suprasellar glioma), underwent plain MRI followed by PWI using a 1.5T unit. In each tumor, the mean and maximum values of relative cerebral blood volume (rCBV), as well as the relative peak height (rPH) and the relative percentage of signal intensity recovery (rPSR) were calculated. Results: The high perfusion tumors were: macroadenomas, meningiomas, squamous-papillary type of craniopharyngiomas, hemangioblastoma, glioma and metastasis. The low perfusion neoplasms included adamantinomatous type of craniopharyngiomas. By comparing adenomas and meningiomas, we found statistically significant differences in the mean and maximum rCBV values (p = 0.026 and p = 0.019, respectively), but not in rPH and rPSR. The maximum rCBV values >7.14 and the mean rCBV values >5.74 with the typical perfusion curve were very suggestive of the diagnosis of meningioma. There were differences between adenomas and other high perfusion tumors in rPH and rPSR values. Conclusions: PWI can provide additional information helpful in differential diagnosis of sellar/parasellar tumors. In our opinion PWI, as an easy to perform and fast technique should be incorporated into the MR protocol of all intracranial neoplasms including sellar/parasellar tumors.
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De-Sheng Shang
Full Text Available BACKGROUND: Diffusion-weighted magnetic resonance imaging (DWI has been introduced in head and neck cancers. Due to limitations in the performance of laryngeal DWI, including the complex anatomical structure of the larynx leading to susceptibility effects, the value of DWI in differentiating benign from malignant laryngeal lesions has largely been ignored. We assessed whether a threshold for the apparent diffusion coefficient (ADC was useful in differentiating preoperative laryngeal carcinomas from precursor lesions by turbo spin-echo (TSE DWI and 3.0-T magnetic resonance. METHODS: We evaluated DWI and the ADC value in 33 pathologically proven laryngeal carcinomas and 17 precancerous lesions. RESULTS: The sensitivity, specificity, and accuracy were 81.8%, 64.7%, 76.0% by laryngostroboscopy, respectively. The sensitivity, specificity, and accuracy of conventional magnetic resonance imaging were 90.9%, 76.5%, 86.0%, respectively. Qualitative DWI analysis produced sensitivity, specificity, and accuracy values of 100.0, 88.2, and 96.0%, respectively. The ADC values were lower for patients with laryngeal carcinoma (mean 1.195±0.32×10(-3 mm(2/s versus those with laryngeal precancerous lesions (mean 1.780±0.32×10(-3 mm(2/s; P<0.001. ROC analysis showed that the area under the curve was 0.956 and the optimum threshold for the ADC was 1.455×10(-3 mm(2/s, resulting in a sensitivity of 94.1%, a specificity of 90.9%, and an accuracy of 92.9%. CONCLUSIONS: Despite some limitations, including the small number of laryngeal carcinomas included, DWI may detect changes in tumor size and shape before they are visible by laryngostroboscopy. The ADC values were lower for patients with laryngeal carcinoma than for those with laryngeal precancerous lesions. The proposed cutoff for the ADC may help distinguish laryngeal carcinomas from laryngeal precancerous lesions.
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Baunin, C.; Schmidt, G.; Aschero, A.; Ruocco, A.; Bourliere, B.; Gorincour, G.; Desvignes, C.; Colavolpe, N.; Petit, P. [Hopital Timone Enfants, Service d' Imagerie Pediatrique et Prenatale, Marseille Cedex 05 (France); Baumstarck, K.; Auqier, P. [Faculte de Medecine de Marseille, Service de Sante Publique, Marseille Cedex 05 (France); Bouvier, C. [Hopital Timone, Service d' Anatomopathologie, Marseille Cedex 05 (France); Gentet, J.C. [Hopital Timone Enfants, Service d' Oncologie Pediatrique, Marseille Cedex 05 (France); Bollini, G. [Hopital Timone Enfants, Service d' Orthopedie Pediatrique, Marseille Cedex 05 (France)
2012-09-15
Preoperative diffusion-weighted MRI (DW-MRI) has been described as an efficient method to differentiate good and poor responders to chemotherapy in osteosarcoma patients. A DW-MRI performed earlier during treatment could be helpful in monitoring chemotherapy. To assess the accuracy of DW-MRI in evaluating response to chemotherapy in the treatment of osteosarcoma, more specifically at mid-course of treatment. This study was carried out on a prospective series of adolescents treated for long-bone osteosarcoma. MR examinations were performed at diagnosis (MRI-1), at mid-course of chemotherapy (MRI-2), and immediately before surgery (MRI-3). A DW sequence was performed using diffusion gradients of b0 and b900. The apparent diffusion coefficients (ADC1, ADC2, ADC3, respectively), their differentials (ADC2 - ADC1 and ADC3 - ADC1), and their variation (ADC2 - ADC1/ADC1 and ADC3 - ADC1/ADC1) were calculated for each of these three time points. Fifteen patients were included. Patients with no increase in ADC showed a poor response to chemotherapy on their histology results. At mid-course, the three calculated values were significantly different between good and poor responders. ADC2 - ADC1 enabled us to detect, with 100% specificity, four out of seven of the poor responders. There was no significant difference in the values at MRI-3 between the two groups. DW-MRI performed both at baseline and mid-course of neoadjuvant chemotherapy is an efficient method to predict further histological response of osteosarcoma. This method could be used as an early prognostic factor to monitor preoperative chemotherapy. (orig.)
Woo, Sungmin; Cho, Jeong Yeon; Kim, Sang Youn; Kim, Seung Hyup
2014-12-01
Until now, several investigators have explored the value of diffusion-weighted magnetic resonance imaging (DWI) for the preoperative tumor grading of endometrial cancer. However, the diagnostic value of DWI with quantitative analysis of apparent diffusion coefficient (ADC) has been controversial. To explore the role of histogram analysis of ADC maps based on entire tumor volume in determining the grade of endometrial cancer. This study was IRB-approved with waiver of informed consent. Thirty-three patients with endometrial cancer underwent DWI (b = 0, 600, 1000 s/mm(2)), and corresponding ADC maps were acquired. Regions of interest (ROIs) were drawn on all slices of the ADC map in which the tumor was visualized including areas of necrosis to derive volume-based histographic ADC data. Histogram parameters (5th-95th percentiles, mean, standard deviation, skewness, kurtosis) were correlated with histological grade using one-way ANOVA with Tukey-Kramer test for post hoc comparisons, and were compared between high (grade 3) and low (grades 1/2) grade using Student t-test. ROC curve analysis was performed to determine the optimum threshold value for each parameter, and their corresponding sensitivity and specificity. The standard deviation, quartile, 75th, 90th, and 95th percentiles of ADC showed significant differences between grades (P ≤ 0.03 for all) and between high and low grades (P ≤ 0.024 for all). There were no significant correlations between tumor grade and other parameters. ROC curve analysis yielded sensitivities and specificities of 75% and 96%, 62.5% and 92%, 100% and 52%, 100% and 72%, and 100% and 88%, using standard deviation, quartile, 75th, 90th, and 95th percentiles for determining high grade with corresponding areas under the curve (AUCs) of 0.787, 0.792, 0.765, 0.880, and 0.925, respectively. Histogram analysis of ADC maps based on entire tumor volume can be useful for predicting the histological grade of endometrial cancer. The 90th and 95th
Kumai, Tsukasa; Muneta, Takeshi; Tsuchiya, Akihiro; Shiraishi, Masaharu; Ishizaki, Yoshitaka; Sugimoto, Kazuya; Samoto, Norihiro; Isomoto, Shinji; Tanaka, Yasuhito; Takakura, Yoshinori
2014-07-01
Hyaluronic acid (HA) with a high molecular weight of 2700 kDa is approved in Japan to treat osteoarthritis of the knee, periarthritis scapulohumeralis, and knee pain associated with rheumatoid arthritis. The purpose of this preliminary study was to investigate the short-term efficacy, safety, and injectable volume of HA in the treatment of enthesopathies. A total of 61 patients (16 with lateral epicondylitis, 14 with patellar tendinopathy, 15 with insertional Achilles tendinopathy, and 16 with plantar fasciitis) were each administered a single injection of HA (up to 2.5 ml). Efficacy and safety were assessed by comparing the visual analog scale (VAS) for pain and local symptoms before injection (baseline) and at 1 week after injection. We also investigated the injectable volume by means of the difference in syringe weight before and after injection and by the judgment of the administering investigator. The injection of HA resulted in a change in VAS (mean ± SD) of -2.20 ± 2.26 cm for the four sites overall and -2.55 ± 2.43 cm for lateral epicondylitis, -2.01 ± 2.16 cm for patellar tendinopathy, -1.80 ± 1.91 cm for insertional Achilles tendinopathy, and -2.38 ± 2.61 cm for plantar fasciitis. The injection of HA also improved local symptoms in each site. It was also determined that 2.5 ml of HA can be injected in each of the four sites. A single injection of HA resulted in similar improvements of pain in each of the four enthesopathies (lateral epicondylitis, patellar tendinopathy, insertional Achilles tendinopathy, and plantar fasciitis). These results suggest that HA could be clinically effective in the treatment of enthesopathies.
Sanford, W. E.
2015-12-01
Age distributions of base flow to streams are important to estimate for predicting the timing of water-quality responses to changes in distributed inputs of nutrients or pollutants at the land surface. Simple models of shallow aquifers will predict exponential age distributions, but more realistic 3-D stream-aquifer geometries will cause deviations from an exponential curve. In addition, in fractured rock terrains the dual nature of the effective and total porosity of the system complicates the age distribution further. In this study shallow groundwater flow and advective transport were simulated in two regions in the Eastern United States—the Delmarva Peninsula and the upper Potomac River basin. The former is underlain by layers of unconsolidated sediment, while the latter consists of folded and fractured sedimentary rocks. Transport of groundwater to streams was simulated using the USGS code MODPATH within 175 and 275 watersheds, respectively. For the fractured rock terrain, calculations were also performed along flow pathlines to account for exchange between mobile and immobile flow zones. Porosities at both sites were calibrated using environmental tracer data (3H, 3He, CFCs and SF6) in wells and springs, and with a 30-year tritium record from the Potomac River. Carbonate and siliciclastic rocks were calibrated to have mobile porosity values of one and six percent, and immobile porosity values of 18 and 12 percent, respectively. The age distributions were fitted to Weibull functions. Whereas an exponential function has one parameter that controls the median age of the distribution, a Weibull function has an extra parameter that controls the slope of the curve. A weighted Weibull function was also developed that potentially allows for four parameters, two that control the median age and two that control the slope, one of each weighted toward early or late arrival times. For both systems the two-parameter Weibull function nearly always produced a substantially
Directory of Open Access Journals (Sweden)
Stefan Schob
2016-10-01
Full Text Available BACKGROUND: Thyroid carcinomas represent the most frequent endocrine malignancies. Recent studies were able to distinguish malignant from benign nodules of the thyroid gland with diffusion-weighted imaging (DWI. Although this differentiation is undoubtedly helpful, presurgical discrimination between well-differentiated and undifferentiated carcinomas would be crucial to define the optimal treatment algorithm. Therefore, the aim of this study was to investigate if readout-segmented multishot echo planar DWI is able to differentiate between differentiated and undifferentiated subtypes of thyroid carcinomas. PATIENTS AND METHODS: Fourteen patients with different types of thyroid carcinomas who received preoperative DWI were included in our study. In all lesions, apparent diffusion coefficient (ADCmin, ADCmean, ADCmax, and D were estimated on the basis of region of interest measurements after coregistration with T1-weighted, postcontrast images. All tumors were resected and analyzed histopathologically. Ki-67 index, p53 synthesis, cellularity, and total and average nucleic areas were estimated using ImageJ version 1.48. RESULTS: Analysis of variance revealed a statistically significant difference in ADCmean values between differentiated and undifferentiated thyroid carcinomas (P = .022. Spearman Rho calculation identified significant correlations between ADCmax and cell count (r = 0.541, P = .046 as well as between ADCmax and total nuclei area (r = 0.605, P = .022. CONCLUSION: DWI can distinguish between differentiated and undifferentiated thyroid carcinomas.
Preliminary Investigation of a Paraglider
Rogallo, Francis M.; Lowry, John G.; Croom, Delwin R.; Taylor, Robert T.
1960-01-01
A preliminary investigation of the aerodynamic and control characteristics of a flexible glider similar to a parachute in construction has been made at the Langley Research Center to evaluate its capabilities as a reentry glider. Preliminary weight estimates of the proposed vehicle indicate that such a structure can be made with extremely low wing loading. Maximum temperatures during the reentry maneuver might be held as low as about 1,500 F. The results of wind-tunnel and free-glide tests show that the glider when constructed of nonporous material performed extremely well at subsonic speeds and could be flown at angles of attack from about 200 to 900. At supersonic speeds the wing showed none of the unfavorable tendencies exhibited by conventional parachutes at these speeds, such as squidding and breathing. Several methods of packing and deploying the glider have been successfully demonstrated. The results of this study indicate that this flexible-lifting-surface concept may provide a lightweight controllable paraglider for manned space vehicles.
Institute of Scientific and Technical Information of China (English)
2011-01-01
Refers to:The Weighted Estimates of the Schr(o)dinger Operators on the Nilpotent Lie Group Journal of Mathematical Research and Exposition,Volume 30,Issue 6,20November 2010,Pages 1117-1124Ling Juan HAN and Qiao Zhen MA
Directory of Open Access Journals (Sweden)
Fabiane Aparecida Canaan Rezende
2009-08-01
Full Text Available OBJETIVO: Avaliar a validade de fórmulas preditivas de peso e de altura, bem como a composição corporal em homens adultos. MÉTODOS: A amostra constituiu-se de 98 homens saudáveis, com idades entre 20 e 58 anos. Para a análise das equações de estimativa de peso e altura, coletaram-se dados de peso, altura, altura do joelho, envergadura, semi-envergadura, circunferências da panturrilha e do braço e dobra cutânea subescapular. Avaliou-se a composição corporal por meio de bioimpedância elétrica. RESULTADOS: O peso estimado diferiu significantemente do peso aferido (pOBJECTIVE: The objective of this study was to evaluate the validity of equations that predict weight, height and body composition in adult men. METHODS: The sample consisted of 98 healthy men aged from 20 to 58 years. In order to analyze the equations, weight, height, knee height, arm span, half-arm span, calf and arm circumference and subscapular skinfold thickness were collected. Body composition was determined by bioimpedance. RESULTS: Estimated weights were significantly different from measured weights (p<0.001. The only equation that estimated height properly was that validated for adult Caucasian men. Both arm span (r=0.789; d=2.67; p<0.001 and half-arm span (r=0.790; d=2.51; p<0.001 overestimated height. When weight and height estimates were used to calculate body mass index, underweight was overestimated and overweight was underestimated, except when height was estimated with the equations for adult Caucasian men. CONCLUSION: The equation to estimate height validated for adult Caucasian men estimated the height of adult young men properly; the other validated equations presented significant differences. It is important to validate the equations assessed in this study in other population groups, making sure to use the estimated weights and heights to calculate body mass index.
... Health Information Weight Management English English Español Weight Management Obesity is a chronic condition that affects more ... Liver (NASH) Heart Disease & Stroke Sleep Apnea Weight Management Topics About Food Portions Bariatric Surgery for Severe ...
Variable-complexity aerodynamic optimization of an HSCT wing using structural wing-weight equations
Hutchison, M. G.; Unger, E. R.; Mason, W. H.; Grossman, B.; Haftka, R. T.
1992-01-01
A new approach for combining conceptual and preliminary design techniques for wing optimization is presented for the high-speed civil transport (HSCT). A wing-shape parametrization procedure is developed which allows the linking of planform and airfoil design variables. Variable-complexity design strategies are used to combine conceptual and preliminary-design approaches, both to preserve interdisciplinary design influences and to reduce computational expense. In the study, conceptual-design-level algebraic equations are used to estimate aircraft weight, supersonic wave drag, friction drag and drag due to lift. The drag due to lift and wave drag are also evaluated using more detailed, preliminary-design-level techniques. The methodology is applied to the minimization of the gross weight of an HSCT that flies at Mach 3.0 with a range of 6500 miles.
Sensitivity to Estimation Errors in Mean-variance Models
Institute of Scientific and Technical Information of China (English)
Zhi-ping Chen; Cai-e Zhao
2003-01-01
In order to give a complete and accurate description about the sensitivity of efficient portfolios to changes in assets' expected returns, variances and covariances, the joint effect of estimation errors in means, variances and covariances on the efficient portfolio's weights is investigated in this paper. It is proved that the efficient portfolio's composition is a Lipschitz continuous, differentiable mapping of these parameters under suitable conditions. The change rate of the efficient portfolio's weights with respect to variations about riskreturn estimations is derived by estimating the Lipschitz constant. Our general quantitative results show thatthe efficient portfolio's weights are normally not so sensitive to estimation errors about means and variances .Moreover, we point out those extreme cases which might cause stability problems and how to avoid them in practice. Preliminary numerical results are also provided as an illustration to our theoretical results.
Keshavarz, Behrang; Campos, Jennifer L; DeLucia, Patricia R; Oberfeld, Daniel
2017-04-01
Estimating time to contact (TTC) involves multiple sensory systems, including vision and audition. Previous findings suggested that the ratio of an object's instantaneous optical size/sound intensity to its instantaneous rate of change in optical size/sound intensity (τ) drives TTC judgments. Other evidence has shown that heuristic-based cues are used, including final optical size or final sound pressure level. Most previous studies have used decontextualized and unfamiliar stimuli (e.g., geometric shapes on a blank background). Here we evaluated TTC estimates by using a traffic scene with an approaching vehicle to evaluate the weights of visual and auditory TTC cues under more realistic conditions. Younger (18-39 years) and older (65+ years) participants made TTC estimates in three sensory conditions: visual-only, auditory-only, and audio-visual. Stimuli were presented within an immersive virtual-reality environment, and cue weights were calculated for both visual cues (e.g., visual τ, final optical size) and auditory cues (e.g., auditory τ, final sound pressure level). The results demonstrated the use of visual τ as well as heuristic cues in the visual-only condition. TTC estimates in the auditory-only condition, however, were primarily based on an auditory heuristic cue (final sound pressure level), rather than on auditory τ. In the audio-visual condition, the visual cues dominated overall, with the highest weight being assigned to visual τ by younger adults, and a more equal weighting of visual τ and heuristic cues in older adults. Overall, better characterizing the effects of combined sensory inputs, stimulus characteristics, and age on the cues used to estimate TTC will provide important insights into how these factors may affect everyday behavior.
Kim, Eung Seok; Choi, Hyun Il
2012-04-01
An increase in the occurrence of sudden local flooding of great volume and short duration has caused significant danger and loss of life and property in Korea as well as many other parts of the World. Since such floods usually accompanied by rapid runoff and debris flow rise quite quickly with little or no advance warning to prevent flood damage, this study presents a new flash flood indexing methodology to promptly provide preliminary observations regarding emergency preparedness and response to flash flood disasters in small ungauged catchments. Flood runoff hydrographs are generated from a rainfall-runoff model for the annual maximum rainfall series of long-term observed data in the two selected small ungauged catchments. The relative flood severity factors quantifying characteristics of flood runoff hydrographs are standardized by the highest recorded maximum value, and then averaged to obtain the flash flood index only for flash flood events in each study catchment. It is expected that the regression equations between the proposed flash flood index and rainfall characteristics can provide the basis database of the preliminary information for forecasting the local flood severity in order to facilitate flash flood preparedness in small ungauged catchments.
Energy Technology Data Exchange (ETDEWEB)
Lemke, A.-J.; Brinkmann, M.; Felix, R. [Universitaetsklinikum Charite, Berlin (Germany). Klinik fuer Strahlenheilkunde; Pascher, A.; Steinmueller, T.; Settmacher, U.; Neuhaus, P. [Universitaetsklinikum Charite, Berlin (Germany). Klinik fuer Allgemein-, Viszeral- und Transplantationschirurgie
2003-09-01
Purpose: Due to the shortage of cadaver donors, living related liver donation (LRLD) has emerged as an alternative to cadaver donation. The expected graft weight is one of the main determinants for donor selection. This study investigates the accuracy of preoperatively performed CT-volumetry to predict the actual weight of the right liver lobe graft. Materials and methods: In a prospective study the weight of the right hepatic lobe was calculated by volumetric analysis based on CT in 33 patients (21 females, 12 males, mean age 42.1 years, median age 41 years) prior to living related liver donation. Graft weight was calculated as the product of CT-based graft volume and 1.00 g/ml (the approximated density of healthy liver parenchyma). The calculated weight was compared with the intraoperatively measured weight of the harvested right hepatic lobe. The difference was used to determine a correction factor for estimating the actual graft weight. Results: Based on the assumption of a parenchymal density of 1.00 g/ml, the preoperatively estimated graft weight (mean 980 g {+-} 168 g) deviated + 33% from the intraoperatively measured right hepatic lobe weight (mean 749 g {+-} 170 g). By reducing the preoperatively predicted weight of the right hepatic lobe with a correction factor of 0.75, the actual graft weight can be calculated. [German] Ziel: Vor dem Hintergrund des bestehenden Mangels an Spenderorganen stellt die Leberlappen-Lebendspende eine Alternative zur Leichenspende dar. Massgeblich fuer die Auswahl des Spenders ist das zu erwartende Transplantatgewicht. Ziel der Studie war, die Voraussagegenauigkeit der praeoperativen CT-gestuetzten Gewichtsbestimmung auf Basis einer Volumetrie des rechten Leberlappens bezueglich des intraoperativen Transplantatgewichts zu ueberpruefen. Methodik: In einer prospektiven Studie wurde bei 33 Patienten (21 Frauen, 12 Maennern, mittleres Alter 42,1 Jahre, medianes Alter 41 Jahre) vor Leberlappen-Lebendspende auf der Basis von CT
Ackerman, Margareta; Branzei, Simina; Loker, David
2011-01-01
In this paper we investigate clustering in the weighted setting, in which every data point is assigned a real valued weight. We conduct a theoretical analysis on the influence of weighted data on standard clustering algorithms in each of the partitional and hierarchical settings, characterising the precise conditions under which such algorithms react to weights, and classifying clustering methods into three broad categories: weight-responsive, weight-considering, and weight-robust. Our analysis raises several interesting questions and can be directly mapped to the classical unweighted setting.
Institute of Scientific and Technical Information of China (English)
金兰; 朴宪镇
2001-01-01
In this thesis, we propose test statistics based on the weighted symmetric estimators for seasonal time series autoregressive models with a unit root and derive representations for the limit distributions of the estimators and pivotal statistics. The empirical percentiles of the distributions for time series that has a unit root at the seasonal lag are computed for finite samples and limit case by Monte Carlo method. By comparison of the empirical powers, we show that the test statistics with the weighted symmetric estimators are more powerful than that with the ordinary least squares estimators and simple symmetric estimators for the seasonal means model.%本文提出对季节性时间序列利用加权对称估计量的单位根检验，导出相应统计量的极限分布.用MonteCarlo方法计算经验百分位数及检验势，并对最小平方估计量，简单对称估计量和加权对称估计量的经验检验势作了比较.
Preliminary analysis of construction investment estimation on petrochemical project%浅析石油化工项目建设投资估算
Institute of Scientific and Technical Information of China (English)
陈瑜芳
2011-01-01
石油化工项目的建设投资估算是项目前期工作的重要内容之一.在分析石油化工项目的特点、说明投资估算的重要性和范围的基础上,提出投资估算编制应注重资料搜集、制定投资估算原则、编制方法及确定工程量等环节.并分析说明了如何根据项目的具体情况,选取适当的估算方法完成项目投资估算.最终提出了投资估算中应注意的问题.%The construction investment estimation of petrochemical project is one of important work activities in the early stage of project. On the basis of analysis of the characteristics of petroleum refining and petrochemical engineering projects and the importance of investment estimation and its scope, the investment estimate preparation should focus on such steps as data collection, development of investment estimation method and principles and determination of bill of quantities, etc. An example is provided to illustrate how to select a proper estimation method to perform the investment estimate according to specific project conditions. The precautions in capital investment estimation are finally presented.
Goode, Daniel J.; Cravotta, Charles A.; Hornberger, Roger J.; Hewitt, Michael A.; Hughes, Robert E.; Koury, Daniel J.; Eicholtz, Lee W.
2011-01-01
This report, prepared in cooperation with the Pennsylvania Department of Environmental Protection (PaDEP), the Eastern Pennsylvania Coalition for Abandoned Mine Reclamation, and the Dauphin County Conservation District, provides estimates of water budgets and groundwater volumes stored in abandoned underground mines in the Western Middle Anthracite Coalfield, which encompasses an area of 120 square miles in eastern Pennsylvania. The estimates are based on preliminary simulations using a groundwater-flow model and an associated geographic information system that integrates data on the mining features, hydrogeology, and streamflow in the study area. The Mahanoy and Shamokin Creek Basins were the focus of the study because these basins exhibit extensive hydrologic effects and water-quality degradation from the abandoned mines in their headwaters in the Western Middle Anthracite Coalfield. Proposed groundwater withdrawals from the flooded parts of the mines and stream-channel modifications in selected areas have the potential for altering the distribution of groundwater and the interaction between the groundwater and streams in the area. Preliminary three-dimensional, steady-state simulations of groundwater flow by the use of MODFLOW are presented to summarize information on the exchange of groundwater among adjacent mines and to help guide the management of ongoing data collection, reclamation activities, and water-use planning. The conceptual model includes high-permeability mine voids that are connected vertically and horizontally within multicolliery units (MCUs). MCUs were identified on the basis of mine maps, locations of mine discharges, and groundwater levels in the mines measured by PaDEP. The locations and integrity of mine barriers were determined from mine maps and groundwater levels. The permeability of intact barriers is low, reflecting the hydraulic characteristics of unmined host rock and coal. A steady-state model was calibrated to measured groundwater
Shoheiber, O; Biskupiak, J E; Nash, D B
1997-11-01
Morbidly obese patients enrolled in a rapid weight reduction program are at a high risk of developing gallstones. Two multicenter, placebo-controlled, randomized, double-blind trials have demonstrated that the prophylactic use of ursodiol in males and females 18 to 70 years of age is effective for the prevention of gallstone formation in this patient population. This study examines the cost consequences associated with the prophylactic use of ursodiol. A medical decision analysis model for the prophylactic administration of ursodiol in morbidly obese patients undergoing rapid weight reduction by either gastric bypass surgery or very-low-calorie-diet, was developed through the use of data from two clinical trials and review of the related literature. The expert opinion of clinicians from the fields of internal medicine, gastroenterology and surgery were solicited. Financial data for the charges associated with cholecystectomies, physician fees and ursodiol were obtained from current financial databases. The model demonstrates that the prophylactic administration of ursodiol, in morbidly obese patients undergoing rapid weight reduction, results in cost savings. Sensitivity analysis was performed to illustrate that the cost savings achieved by the prophylactic use of ursodiol were valid over a realistic range of charges and assumptions. The decision model may allow health care decision makers to apply their own data to the model to determine the cost savings obtainable through the prophylactic use of ursodiol in patients undergoing rapid weight reduction.
Institute of Scientific and Technical Information of China (English)
谈元鹏; 许刚; 赵妙颖
2015-01-01
为了实现对电力工程造价高效、精确的估算，提出了一种电力工程造价的随机权深度神经学习估算算法（Random Weighted Deep Neural Learning，RWDNL）。通过构建外权随机的带有小中间层的多隐层神经网络模型，利用神经网络深度学习实现了对海量数据有效特征的提取以及电力工程项目造价估算。数值仿真实验结果表明该方法使工程造价估算精度和速度大大提高，可获得令人满意的泛化能力。%In order to realize an efficient and accurate cost estimation of power engineering project, a cost estimation method for power engineering project with big data is proposed based on a so-called Random Weighted Deep Neural Learning(RWDNL)algorithm. By means of building a multi-layer random weighted neural network with a small central layer, effective features are extracted from mass engineering data and power engineering project cost estimation is also real-ized by neural network deep learning. The experimental results demonstrate the outstanding performances of the proposed RWDNL method on estimation time consume and estimation accuracy, as well as its satisfactory generalization ability.
Institute of Scientific and Technical Information of China (English)
黄超; 张剑云; 朱家兵; 张正言
2016-01-01
Because classical DOA(Direction of Arrival)estimation algorithms often fail to deal with coherent signals,a new DOA estimation algorithm based on weighted-modified MUSIC(Multiple Signal Classifi-cation) algorithm was proposed in this paper.In this algorithm,the data covariance matrix was reconstructed at first, and new noise subspace was constructed then.Finally the eigenvectors of noise subspace were weighted based on the size of the gain value,and the DOA estimation of coherent signals was completed.Computer simulation indi-cated the algorithm estimated the DOA of coherent signals successfully.%针对传统波达方向估计算法对相干信号失效的问题，提出了基于加权改进多信号分类法(MUSIC)的波达方向估计算法。该算法首先对接收数据协方差矩阵进行重构，进而构造出新的噪声子空间，再根据特征值大小对噪声子空间特征向量进行加权，完成对相干信号的波达方向估计。仿真分析表明，算法成功地完成了对相干信号的波达方向估计。
Boëlle, P Y; Bernillon, P; Desenclos, J C
2009-05-14
As of 12 May 2009, 5,251 cases of the new influenza A(H1N1) have been officially reported to the World Health Organization (WHO) from 30 countries, with most of the identified cases exported from Mexico where a local epidemic has been going on for the last two months. Sustained human-to-human transmission is necessary to trigger influenza pandemic and estimating the reproduction ratio (average number of secondary cases per primary case) is necessary for forecasting the spread of infection. We use two methods to estimate the reproduction ratio from the epidemic curve in Mexico using three plausible generation intervals (the time between primary and secondary case infection). As expected, the reproduction ratio estimates were highly sensitive to assumptions regarding the generation interval, which remains to be estimated for the current epidemic. Here, we suggest that the reproduction ratio was less than 2.2 - 3.1 in Mexico, depending on the generation interval. Monitoring and updating the reproduction ratio estimate as the epidemic spreads outside Mexico into different settings should remain a priority for assessing the situation and helping to plan public health interventions.
... obese. Achieving a healthy weight can help you control your cholesterol, blood pressure and blood sugar. It ... use more calories than you eat. A weight-control strategy might include Choosing low-fat, low-calorie ...
DEFF Research Database (Denmark)
Ackerman, Margareta; Ben-David, Shai; Branzei, Simina
2012-01-01
We investigate a natural generalization of the classical clustering problem, considering clustering tasks in which different instances may have different weights.We conduct the first extensive theoretical analysis on the influence of weighted data on standard clustering algorithms in both...... the partitional and hierarchical settings, characterizing the conditions under which algorithms react to weights. Extending a recent framework for clustering algorithm selection, we propose intuitive properties that would allow users to choose between clustering algorithms in the weighted setting and classify...
... baby, taken just after he or she is born. A low birth weight is less than 5.5 pounds. A high ... weight is more than 8.8 pounds. A low birth weight baby can be born too small, too early (premature), or both. This ...
Mario M. Osorio-Arce; Segura-Correa, José C.
2010-01-01
The objective of this study was to determine the breed-direct, breed-maternal and heterosis effects for weaning and yearling weights of Brahman cattle and its crosses with Charolais, Simmental and Brown Swiss breeds in a beef cattle system in Tabasco, Mexico. The climate of the region is tropical humid. Data were obtained on 1217 calves born from 1995 to 2007; among the 16 breed-group combinations one was purebred mating (Brahman), 3 two-breed static crosses, 7 three-breed static crosses and ...
DEFF Research Database (Denmark)
Hede, Mikkel Ulfeldt; Nielsen, Lars; Clemmensen, Lars B
2011-01-01
Estimates of past sea-level variations based on different methods and techniques have been presented in a range of studies, including interpretation of beach ridge characteristics. In Denmark, Holocene beach ridge plains have been formed during the last c. 7700 years, a period characterised by both...... (i.e. sea-level) at the time of deposition. Combining the variations in height of the downlaps (in meters above present mean sea-level) with optically stimulated luminescence dating techniques provides estimates of relative sealevel at specific times....... been chosen as a key-locality in this project, as it is located relatively close to the current 0-isobase of isostatic rebound. GPR reflection data have been acquired with shielded 250 MHz Sensors & software antennae along a number of profile lines across beach ridge and swale structures of the Feddet...
Institute of Scientific and Technical Information of China (English)
邵月红; 张万昌
2009-01-01
In terms of the Doppler radar rainfall estimation algorithms, such as the Z-R relation, the average calibration, the Kalman filter, the optimum interpolation, the variation, the optimum Kalman filter and the variation Kalman, the regional rainfall are estimated and compared with those interpolated from the observations in the automatic precipitation observatories. The results suggest that the performance of each algorithms mentioned above is not very satisfied. The statistical analyses are applied to the estimated results, and the statistical weight matrix approach is employed to improve the accuracy of the regional rainfall estimations. The results reveal that the precision of the regional rainfall estimation from the average calibration, the Kalman filter, the optimum interpolation, the variation, the optimum Kalman filter and the variation Kalman are evidently superior to those from the Z-R relation, and the regional rainfall estimation from the Z-R relation shows the evident underestimation. What's more, the results further show that the accuracy of the estimated regional rainfall derived from the statistical weight matrix approach by integrating all individual algorithm mentioned above is evidently higher than that obtained by any individual ones. The quantitative rainfall estimations with the statistical weight matrix approach are very close to the automatic rain-gage network observed either in the spatial distribution or in the location of the intense precipitation centers. The regional precipitation estimation of the statistic weight matrix approach can truly reflect the precipitation status over the ground surface and might be served as a promising conventional method for estimation of the regional rainfall for the studied region.%Z～R关系法和6种雷达雨量计联合法反演的区域降水量与雨量计观测得到的降水场存在较大的误差,将这7种降水估测结果作为信息源,采用统计权重矩阵法对上述7种反演
Redemann, J.; Livingston, J.; Shinozuka, Y.; Kacenelenbogen, M.; Russell, P.; LeBlanc, S.; Vaughan, M.; Ferrare, R.; Hostetler, C.; Rogers, R.;
2014-01-01
We have developed a technique for combining CALIOP aerosol backscatter, MODIS spectral AOD (aerosol optical depth), and OMI AAOD (absorption aerosol optical depth) retrievals for the purpose of estimating full spectral sets of aerosol radiative properties, and ultimately for calculating the 3-D distribution of direct aerosol radiative forcing. We present results using one year of data collected in 2007 and show comparisons of the aerosol radiative property estimates to collocated AERONET retrievals. Use of the recently released MODIS Collection 6 data for aerosol optical depths derived with the dark target and deep blue algorithms has extended the coverage of the multi-sensor estimates towards higher latitudes. We compare the spatio-temporal distribution of our multi-sensor aerosol retrievals and calculations of seasonal clear-sky aerosol radiative forcing based on the aerosol retrievals to values derived from four models that participated in the latest AeroCom model intercomparison initiative. We find significant inter-model differences, in particular for the aerosol single scattering albedo, which can be evaluated using the multi-sensor A-Train retrievals. We discuss the major challenges that exist in extending our clear-sky results to all-sky conditions. On the basis of comparisons to suborbital measurements, we present some of the limitations of the MODIS and CALIOP retrievals in the presence of adjacent or underlying clouds. Strategies for meeting these challenges are discussed.
Estimativa do peso da carcaça e dos cortes dianteiro, costilhar e serrote a partir do peso vivo em novilhos hereford Estimate of carcass weight and cuts fore quarter, ribs and hind pistol from live weight in hereford steers
Directory of Open Access Journals (Sweden)
Pedro Osório Jardim
1996-08-01
Full Text Available O estudo foi realizado com o objetivo de verificar a utilização do peso vivo (PV como estimador do peso da carcaça quente (PCQ, dos cortes dianteiro (PD, costilhar (PC e serrote (PS, assim como, quantificar a relação do PV com o PCQ e principais cortes da carcaça (PD, PC e PS. Foram utilizados 58 novilhos Hereford, criados em campo nativo e abatidos com 36 meses de idade. As equações de regressão obtidas foram: PCQ=-3,97+0,474(PV; PS=4,32+0,050(PV; PC=-5,26+0,092(PV e PD=-0,54+0.043(PV, todas altamente significativas (PFifty eight Hereford steers, raised under native pasture conditions, slaughtered with an average age of thirty months, were used to study the feasibility of the use of live wheight (PV as an estimator of the hot carcass weight (PCQ and of cuts such as fore quarter (PD, ribs (PC and hind pistol (PS, as well as to quantify the relationship of live weight with hot carcass weight and the main carcass cuts (PD, PC and PS. The regression equations obtained were: PCQ =-3.7 + 0.474 (PV; PS = 4.32 + 0.50 (PV; PC = -5.6 + 0.92 (PV and PD =-0.4 + 0.43 (PV, all of them highly significant (P<0.001, showing, respectively, the following determination coefficients: 90.6%, 86.6%, 72.6% and 87.0%. According to these values one might conclude that live weight is a good estimator of hot carcass weight and of its cuts, and may be utilized to sort animals for slaughter and when to sell them.
Institute of Scientific and Technical Information of China (English)
牛成英; 孙秋碧
2015-01-01
基于倾向值加权方法，构造了网络调查总体参数的 Horvitz‐Thompson无偏估计量，并对其方差进行了讨论，分析了利用插补缺失数据后的网络调查样本进行总体参数估计的方差来源，在网络调查总体参数估计方面提出了新的思路和方法。%Based on the propensity score weighting method ,this paper constructs a Horvitz‐Thompson estimator of the web survey population parameters which is an unbiased estimator ,discusses the variance of Horvitz‐Thompson estimator ,analyzes the sources of variance of the population parameters estimator by using the complete sample which is imputed missing data of non‐response unit in the web survey .We have put forward new theory and method in the aspect of parameter estimation of web‐based survey .
Research on Estimation of Take-off Weight of Large and Medium Civil Aircraft%大中型民用飞机起飞总重估算方法研究
Institute of Scientific and Technical Information of China (English)
班凯
2012-01-01
推导了基于发动机推力估算起飞总重和基于旅客座位数估算起飞总重的公式.通过多种大中型喷气式民用客机相关参数的统计值,建立起飞总重对相关参数的多元回归分析模型,通过显著性检验,说明模型是有效的,并据此建立了新的起飞总重估算公式.通过算例结果分析表明,新的起飞总重估算公式具有很高精度.在新机的方案设计阶段若能给定此公式所需的相关参数,可以计算得到相对合理的设计起飞总重值.%Formulas for estimating civil airplane take- off weight based on engine thrust and seating capacity are presented respectively. Through a variety of jet civil airplanes' statistical data of related parameters, the multiple regression analysis model of take- off weight with respect to the related parameters is built. The significance test shows that the model is effective, and a novel formula for estimating civil airplane take- off weight is established. The analysis of examples shows that the new formula is accurate. If the parameters required is given in the scheme design stage,then the relatively reasonable design take-off weight value can be obtained by the method of this paper.
Huang, C. H.; Hsieh, C. H.; Lee, J. D.; Huang, W. C.; Lee, S. T.; Wu, C. T.; Sun, Y. N.; Wu, Y. T.
2012-08-01
With the combined view on the physical space and the medical imaging data, augmented reality (AR) visualization can provide perceptive advantages during image-guided surgery (IGS). However, the imaging data are usually captured before surgery and might be different from the up-to-date one due to natural shift of soft tissues. This study presents an AR-enhanced IGS system which is capable to correct the movement of soft tissues from the pre-operative CT images by using intra-operative ultrasound images. First, with reconstructing 2-D free-hand ultrasound images to 3-D volume data, the system applies a Mutual-Information based registration algorithm to estimate the deformation between pre-operative and intra-operative ultrasound images. The estimated deformation transform describes the movement of soft tissues and is then applied to the pre-operative CT images which provide high-resolution anatomical information. As a result, the system thus displays the fusion of the corrected CT images or the real-time 2-D ultrasound images with the patient in the physical space through a head mounted display device, providing an immersive augmented-reality environment. For the performance validation of the proposed system, a brain phantom was utilized to simulate brain-shift scenario. Experimental results reveal that when the shift of an artificial tumor is from 5mm ~ 12mm, the correction rates can be improved from 32% ~ 45% to 87% ~ 95% by using the proposed system.
Nageswar Rao, M; Ram, Anirudh; Rokade, M A; Raja, P; Rakesh, P S; Chemburkar, Parul; Gajbhiye, S N
2016-07-01
Amba Estuary, which receives effluent from several industries including a petrochemical complex, opens to the southern limits of the Mumbai Harbor. The study was conducted to find out the level of Total Petroleum Hydrocarbons (TPHs) in water and their bioconcentration in ten commercially important fishes from Amba Estuary during different months. In water high concentration of TPHs (39.7 μg/L) was obtained during December (middle of estuary) and minimum value (7.2 μg/L) was observed in September (lower estuarine). The maximum concentration of TPHs was found to be in Trichiurus savala (3.2 µg/g) during December and minimum in Boleophthalmus sp (0.4 µg/g) during May. Irrespective of the monthly variations, TPHs accumulation in all the species was considerably lower than hazardous levels. Although there was no statistical significance between TPHs and total length/weight, the T. savala recording maximum concentration during all months and it can be used as indicator of hydrocarbon pollution in this region.
Saputro, Dewi Retno Sari; Widyaningsih, Purnami
2017-08-01
In general, the parameter estimation of GWOLR model uses maximum likelihood method, but it constructs a system of nonlinear equations, making it difficult to find the solution. Therefore, an approximate solution is needed. There are two popular numerical methods: the methods of Newton and Quasi-Newton (QN). Newton's method requires large-scale time in executing the computation program since it contains Jacobian matrix (derivative). QN method overcomes the drawback of Newton's method by substituting derivative computation into a function of direct computation. The QN method uses Hessian matrix approach which contains Davidon-Fletcher-Powell (DFP) formula. The Broyden-Fletcher-Goldfarb-Shanno (BFGS) method is categorized as the QN method which has the DFP formula attribute of having positive definite Hessian matrix. The BFGS method requires large memory in executing the program so another algorithm to decrease memory usage is needed, namely Low Memory BFGS (LBFGS). The purpose of this research is to compute the efficiency of the LBFGS method in the iterative and recursive computation of Hessian matrix and its inverse for the GWOLR parameter estimation. In reference to the research findings, we found out that the BFGS and LBFGS methods have arithmetic operation schemes, including O(n2) and O(nm).
Floyd, Jessica; ter Kuile, Feiko; Cairns, Matt
2017-01-01
Background Malaria transmission has declined substantially in the 21st century, but pregnant women in areas of sustained transmission still require protection to prevent the adverse pregnancy and birth outcomes associated with malaria in pregnancy (MiP). A recent call to action has been issued to address the continuing low coverage of intermittent preventive treatment of malaria in pregnancy (IPTp). This call has, however, been questioned by some, in part due to concerns about resistance to sulphadoxine-pyrimethamine (SP), the only drug currently recommended for IPTp. Methods and findings Using an existing mathematical model of MiP, we combined estimates of the changing endemicity of malaria across Africa with maps of SP resistance mutations and current coverage of antenatal access and IPTp with SP (IPTp-SP) across Africa. Using estimates of the relationship between SP resistance mutations and the parasitological efficacy of SP during pregnancy, we estimated the varying impact of IPTp-SP across Africa and the incremental value of enhancing IPTp-SP uptake to match current antenatal care (ANC) coverage. The risks of MiP and malaria-attributable low birthweight (mLBW) in unprotected pregnancies (i.e., those not using insecticide-treated nets [ITNs]) leading to live births fell by 37% (33%–41% 95% credible interval [crI]) and 31% (27%–34% 95% crI), respectively, from 2000 to 2015 across endemic areas in sub-Saharan Africa. However, these gains are fragile, and coverage is far from optimal. In 2015, 9.5 million (8.3 million–10.4 million 95% crI) of 30.6 million pregnancies in these areas would still have been infected with Plasmodium falciparum without intervention, leading to 750,000 (390,000–1.1 million 95% crI) mLBW deliveries. In all, 6.6 million (5.6 million–7.3 million 95% crI) of these 9.5 million (69.3%) pregnancies at risk of infection (and 53.4% [16.3 million/30.6 million] of all pregnancies) occurred in settings with near-perfect SP curative
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Patrick G T Walker
2017-02-01
Full Text Available Malaria transmission has declined substantially in the 21st century, but pregnant women in areas of sustained transmission still require protection to prevent the adverse pregnancy and birth outcomes associated with malaria in pregnancy (MiP. A recent call to action has been issued to address the continuing low coverage of intermittent preventive treatment of malaria in pregnancy (IPTp. This call has, however, been questioned by some, in part due to concerns about resistance to sulphadoxine-pyrimethamine (SP, the only drug currently recommended for IPTp.Using an existing mathematical model of MiP, we combined estimates of the changing endemicity of malaria across Africa with maps of SP resistance mutations and current coverage of antenatal access and IPTp with SP (IPTp-SP across Africa. Using estimates of the relationship between SP resistance mutations and the parasitological efficacy of SP during pregnancy, we estimated the varying impact of IPTp-SP across Africa and the incremental value of enhancing IPTp-SP uptake to match current antenatal care (ANC coverage. The risks of MiP and malaria-attributable low birthweight (mLBW in unprotected pregnancies (i.e., those not using insecticide-treated nets [ITNs] leading to live births fell by 37% (33%-41% 95% credible interval [crI] and 31% (27%-34% 95% crI, respectively, from 2000 to 2015 across endemic areas in sub-Saharan Africa. However, these gains are fragile, and coverage is far from optimal. In 2015, 9.5 million (8.3 million-10.4 million 95% crI of 30.6 million pregnancies in these areas would still have been infected with Plasmodium falciparum without intervention, leading to 750,000 (390,000-1.1 million 95% crI mLBW deliveries. In all, 6.6 million (5.6 million-7.3 million 95% crI of these 9.5 million (69.3% pregnancies at risk of infection (and 53.4% [16.3 million/30.6 million] of all pregnancies occurred in settings with near-perfect SP curative efficacy (>99% based on the most recent
Walker, Patrick G T; Floyd, Jessica; Ter Kuile, Feiko; Cairns, Matt
2017-02-01
Malaria transmission has declined substantially in the 21st century, but pregnant women in areas of sustained transmission still require protection to prevent the adverse pregnancy and birth outcomes associated with malaria in pregnancy (MiP). A recent call to action has been issued to address the continuing low coverage of intermittent preventive treatment of malaria in pregnancy (IPTp). This call has, however, been questioned by some, in part due to concerns about resistance to sulphadoxine-pyrimethamine (SP), the only drug currently recommended for IPTp. Using an existing mathematical model of MiP, we combined estimates of the changing endemicity of malaria across Africa with maps of SP resistance mutations and current coverage of antenatal access and IPTp with SP (IPTp-SP) across Africa. Using estimates of the relationship between SP resistance mutations and the parasitological efficacy of SP during pregnancy, we estimated the varying impact of IPTp-SP across Africa and the incremental value of enhancing IPTp-SP uptake to match current antenatal care (ANC) coverage. The risks of MiP and malaria-attributable low birthweight (mLBW) in unprotected pregnancies (i.e., those not using insecticide-treated nets [ITNs]) leading to live births fell by 37% (33%-41% 95% credible interval [crI]) and 31% (27%-34% 95% crI), respectively, from 2000 to 2015 across endemic areas in sub-Saharan Africa. However, these gains are fragile, and coverage is far from optimal. In 2015, 9.5 million (8.3 million-10.4 million 95% crI) of 30.6 million pregnancies in these areas would still have been infected with Plasmodium falciparum without intervention, leading to 750,000 (390,000-1.1 million 95% crI) mLBW deliveries. In all, 6.6 million (5.6 million-7.3 million 95% crI) of these 9.5 million (69.3%) pregnancies at risk of infection (and 53.4% [16.3 million/30.6 million] of all pregnancies) occurred in settings with near-perfect SP curative efficacy (>99%) based on the most recent
Directory of Open Access Journals (Sweden)
Xianyong Yin
Full Text Available With numbers of common variants identified mainly through genome-wide association studies (GWASs, there is great interest in incorporating the findings into screening individuals at high risk of psoriasis. The purpose of this study is to establish genetic prediction models and evaluate its discriminatory ability in psoriasis in Han Chinese population. We built the genetic prediction models through weighted polygenic risk score (PRS using 14 susceptibility variants in 8,819 samples. We found the risk of psoriasis among individuals in the top quartile of PRS was significantly larger than those in the lowest quartile of PRS (OR = 28.20, P < 2.0×10(-16. We also observed statistically significant associations between the PRS, family history and early age onset of psoriasis. We also built a predictive model with all 14 known susceptibility variants and alcohol consumption, which achieved an area under the curve statistic of ~ 0.88. Our study suggests that 14 psoriasis known susceptibility loci have the discriminating potential, as is also associated with family history and age of onset. This is the genetic predictive model in psoriasis with the largest accuracy to date.
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Contreras B Ángela P.
2012-04-01
Full Text Available
Statistical models were used to estimate the bunch dry weight through indirect nondestructive methods in African oil palm (Elaeis guineensis American oil palm (Elaeis oleifera and the interspecific hybrid (E. oleifera x E. guineensis; and compared with the formula proposed by Corley. The studies were conducted at Santa Barbara and Chaparral-Cuernavaca on the Unipalma plantation, located in the eastern palm region of Colombia. Ten palms were selected for each group and 30 bunches were sampled for six months. Polynomial and exponential statistical models were postulated, with the best being linear without intercept. The results confirm and validate the usefulness of the model formulated to estimate the bunch dry weight of African oil palm (E. guineensis, American oil palm (E. oleifera and the interspecific hybrid (OxG; however, it proved more convenient to use the models proposed in this study because they are tailored to the specific environmental conditions of the eastern palm region of Colombia.
Energy Technology Data Exchange (ETDEWEB)
Morales S, J. B.; Sanchez J, J. [UNAM, Facultad de Ingenieria, Circuito Interior s/n, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Espinosa P, G., E-mail: jaimebmoraless@gmail.co [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)
2010-10-15
pools. This work presents Pars and steam injectors models, simulations and results of implementations in a best estimated thermal-hydraulics code, which are to be used for evaluations of these systems as long-term supports to ECCS. Lumped parameter models based on heat and mass balances have also been developed to test required additional best estimated code routines needed for the representation of Pars. (Author)
Ship design methodologies of preliminary design
Papanikolaou, Apostolos
2014-01-01
This book deals with ship design and in particular with methodologies of the preliminary design of ships. The book is complemented by a basic bibliography and five appendices with useful updated charts for the selection of the main dimensions and other basic characteristics of different types of ships (Appendix A), the determination of hull form from the data of systematic hull form series (Appendix B), the detailed description of the relational method for the preliminary estimation of ship weights (Appendix C), a brief review of the historical evolution of shipbuilding science and technology from the prehistoric era to date (Appendix D) and finally a historical review of regulatory developments of ship's damage stability to date (Appendix E). The book can be used as textbook for ship design courses or as additional reading for university or college students of naval architecture courses and related disciplines; it may also serve as a reference book for naval architects, practicing engineers of rel...
Institute of Scientific and Technical Information of China (English)
刘海涛; 魏汝祥; 蒋国萍
2012-01-01
For the excessiveness of operating factors and multi-correlation of variables in software cost estimation, this paer proposes a software cost estimation method based on Partial Least Squares Regression(PLSR). After the variables are weighted, an integrated index named analogue deviation is defined to describe the approximation of data samples. Then an adaptive weight is assigned to sample according to the approximation, and the optimal partial least squares latent variables and weight parameters are calculated by traversal searching. Experimental results show that the prediction error is reduced by 73.61% and 32.34% than multiple linear regression and PLSR respectively.%针对软件成本估算中影响因素较多且自变量间存在多重相关性的特点,提出一种基于加权偏最小二乘回归(PLSR)的软件成本估算方法.定义属性权重,得到描述软件历史数据相似度的加权相似离度.通过计算样本相似度自适应地为样本分配权值,采用遍历搜索的方式确定最优主成分及权值分配参数.实验结果表明,该方法的估算误差比多元线性回归方法减少73.61％,比全局PLSR方法减少32.34％.
Energy Technology Data Exchange (ETDEWEB)
Carr, D.B.; Tolley, H.D.
1982-12-01
This paper investigates procedures for univariate nonparametric estimation of tail probabilities. Extrapolated values for tail probabilities beyond the data are also obtained based on the shape of the density in the tail. Several estimators which use exponential weighting are described. These are compared in a Monte Carlo study to nonweighted estimators, to the empirical cdf, to an integrated kernel, to a Fourier series estimate, to a penalized likelihood estimate and a maximum likelihood estimate. Selected weighted estimators are shown to compare favorably to many of these standard estimators for the sampling distributions investigated.
Weighted triangulation adjustment
Anderson, Walter L.
1969-01-01
The variation of coordinates method is employed to perform a weighted least squares adjustment of horizontal survey networks. Geodetic coordinates are required for each fixed and adjustable station. A preliminary inverse geodetic position computation is made for each observed line. Weights associated with each observed equation for direction, azimuth, and distance are applied in the formation of the normal equations in-the least squares adjustment. The number of normal equations that may be solved is twice the number of new stations and less than 150. When the normal equations are solved, shifts are produced at adjustable stations. Previously computed correction factors are applied to the shifts and a most probable geodetic position is found for each adjustable station. Pinal azimuths and distances are computed. These may be written onto magnetic tape for subsequent computation of state plane or grid coordinates. Input consists of punch cards containing project identification, program options, and position and observation information. Results listed include preliminary and final positions, residuals, observation equations, solution of the normal equations showing magnitudes of shifts, and a plot of each adjusted and fixed station. During processing, data sets containing irrecoverable errors are rejected and the type of error is listed. The computer resumes processing of additional data sets.. Other conditions cause warning-errors to be issued, and processing continues with the current data set.
Weighted triangulation adjustment
Anderson, Walter L.
1969-01-01
The variation of coordinates method is employed to perform a weighted least squares adjustment of horizontal survey networks. Geodetic coordinates are required for each fixed and adjustable station. A preliminary inverse geodetic position computation is made for each observed line. Weights associated with each observed equation for direction, azimuth, and distance are applied in the formation of the normal equations in-the least squares adjustment. The number of normal equations that may be solved is twice the number of new stations and less than 150. When the normal equations are solved, shifts are produced at adjustable stations. Previously computed correction factors are applied to the shifts and a most probable geodetic position is found for each adjustable station. Pinal azimuths and distances are computed. These may be written onto magnetic tape for subsequent computation of state plane or grid coordinates. Input consists of punch cards containing project identification, program options, and position and observation information. Results listed include preliminary and final positions, residuals, observation equations, solution of the normal equations showing magnitudes of shifts, and a plot of each adjusted and fixed station. During processing, data sets containing irrecoverable errors are rejected and the type of error is listed. The computer resumes processing of additional data sets.. Other conditions cause warning-errors to be issued, and processing continues with the current data set.
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Nathalie Neirynck
Full Text Available BACKGROUND: Uremic solute concentration increases as Glomerular Filtration Rate (GFR declines. Weak associations were demonstrated between estimated GFR (eGFR and the concentrations of several small water-soluble and protein-bound uremic solutes (MW500 Da. MATERIALS AND METHODS: In 95 CKD-patients (CKD-stage 2-5 not on dialysis, associations between different eGFR-formulae (creatinine, Cystatin C-based or both and the natural logarithm of the concentration of several LMWP's were analyzed: i.e. parathyroid hormone (PTH, Cystatin C (CystC, interleukin-6 (IL-6, tumor necrosis factor-alpha (TNF-α, leptin, retinol binding protein (RbP, immunoglobin light chains kappa and lambda (Ig-κ and Ig-λ, beta-2-microglobulin (β(2M, myoglobin and fibroblast growth factor-23 (FGF-23. RESULTS: The regression coefficients (R(2 between eGFR, based on the CKD-EPI-Crea-CystC-formula as reference, and the examined LMWP's could be divided into three groups. Most of the LMWP's associated weakly (R(2 0.7. Almost identical R(2-values were found per LMWP for all eGFR-formulae, with exception of CystC and β(2M which showed weaker associations with creatinine-based than with CystC-based eGFR. CONCLUSION: The association between eGFR and the concentration of several LMWP's is inconsistent, with in general low R(2-values. Thus, the use of eGFR to evaluate kidney function does not reflect the concentration of several LMWP's with proven toxic impact in CKD.
山东省现患恶性肿瘤残疾权重的测量%Estimation of disability weights on malignant neoplasms in Shandong province
Institute of Scientific and Technical Information of China (English)
马吉祥; 孙建东; 付振涛; 徐爱强; 郭晓雷; 鹿子龙
2008-01-01
目的 测算各种恶性肿瘤的分病程残疾权重和平均残疾权重,为山东省恶性肿瘤疾病负担研究及肿瘤防治对策制定提供参考依据.方法 在山东省2007年恶性肿瘤现患调查中对所有恶性肿瘤患者的健康状况进行调查,参考全球疾病负担研究的方法 ,利用六级社会功能分级标准对患者残疾状况进行分级和赋值,分别计算20种恶性肿瘤的分病程残疾权重和平均残疾权重及其95%CI.结果 共调查恶性肿瘤患者11757例,所有恶性肿瘤治疗期、恢复期、转移期和晚期的残疾权重分别为0.310、0.218、0.450和0.653,平均残疾权重为0.317(95%CI:0.312～0.321).不同恶性肿瘤和不同病程阶段的残疾权重差别显著,性别间差异无统计学意义.肝癌、骨癌、淋巴瘤和胰腺癌平均残疾权重较高(>0.4),乳腺癌、子宫体癌、子宫颈癌、卵巢癌、喉癌和口咽部癌症相对较低(0.4) for liver cancer, bone cancer, lymphoma and pancreas cancer. Lower DWs (<0.3) were found for breast cancer, cervix uteri, corpus uteri, ovarian cancer, larynx cancer, mouth and oropharynx cancer. Conclusion Stage-specific and average DWs for various cancers were estimated based on a large sample size survey. The average DWs of 0.317 for all cancers indicated that 1/3 healthy year lost for each survived life year of them. The difference of DWs between different cancer and stage provide scientific evidence for cancer prevention strategy development.
Institute of Scientific and Technical Information of China (English)
赵旭; 程维虎; 李婧兰
2012-01-01
The generalized Pareto distribution (GPD) is one of the most important distribution in statistics analysis that has been widely used in finance, insurance, hydrology and meteorology applications and so on. While traditional estimation methods, such as maximum likelihood (ML), methods of moments (MOM) and probability weighted moments (PWM) methods have been extensively applied, the use of these methods are often restricted. Alternative approaches (e.g., generalized probability weighted moments, L-moments and LH-moments) exist but they use complete or non-censored samples. However, censored samples are often encountered in hydrology and meteorology fields. In this article, we propose a computationally easy method from censored data for fitting the GPD, which is resistant against extremely small or large outliers, I.e., they will be robust with the lower and upper breakdown points. This method is based on probability weighted moments. Firstly, we solve shape parameter estimator which has high estimated precision, then the location and scale parameters are given for the GPD. Simulation studies show that the proposed method performs well compared to traditional techniques.%广义Pareto分布(GPD)是统计分析中一个极为重要的分布,被广泛应用于金融、保险、水文及气象等领域.传统的参数估计方法如极大似然估计、矩估计及概率加权矩估计方法等已被广泛应用,但使用中存在一定的局限性.虽然提出很多改进方法如广义概率加权矩估计、L矩和LH矩法等,但都是研究完全样本的估计问题,而在水文及气象等应用领域常出现截尾样本.本文基于概率加权矩理论,利用截尾样本对三参数GPD提出一种应用范围广且简单易行的参数估计方法,可有效减弱异常值的影响.首先求解出具有较高精度的形状参数的参数估计,其次得出位置参数及尺度参数的参数估计.通过Monte Carlo模拟说明该方法估计精度较高.
Francoeur, Richard B
2016-01-01
Addressing subsyndromal depression in cerebrovascular conditions, diabetes, and obesity reduces morbidity and risk of major depression. However, depression may be masked because self-reported symptoms may not reveal dysphoric (sad) mood. In this study, the first wave (2,812 elders) from the New Haven Epidemiological Study of the Elderly (EPESE) was used. These population-weighted data combined a stratified, systematic, clustered random sample from independent residences and a census of senior housing. Physical conditions included progressive cerebrovascular disease (CVD; hypertension, silent CVD, stroke, and vascular cognitive impairment [VCI]) and co-occurring excess weight and/or diabetes. These conditions and interactions (clusters) simultaneously predicted 20 depression items and a latent trait of depression in participants with subsyndromal (including subthreshold) depression (11≤ Center for Epidemiologic Studies Depression Scale [CES-D] score ≤27). The option for maximum likelihood estimation with standard errors that are robust to non-normality and non-independence in complex random samples (MLR) in Mplus and an innovation created by the author were used for estimating unbiased effects from latent trait models with exhaustive specification. Symptom profiles reveal masked depression in 1) older males, related to the metabolic syndrome (hypertension–overweight–diabetes; silent CVD–overweight; and silent CVD–diabetes) and 2) older females or the full sample, related to several diabetes and/or overweight clusters that involve stroke or VCI. Several other disease clusters are equivocal regarding masked depression; a couple do emphasize dysphoric mood. Replicating findings could identify subgroups for cost-effective screening of subsyndromal depression. PMID:28003768
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Francoeur RB
2016-12-01
Full Text Available Richard B Francoeur School of Social Work, Adelphi University, Garden City, NY, USA Abstract: Addressing subsyndromal depression in cerebrovascular conditions, diabetes, and obesity reduces morbidity and risk of major depression. However, depression may be masked because self-reported symptoms may not reveal dysphoric (sad mood. In this study, the first wave (2,812 elders from the New Haven Epidemiological Study of the Elderly (EPESE was used. These population-weighted data combined a stratified, systematic, clustered random sample from independent residences and a census of senior housing. Physical conditions included progressive cerebrovascular disease (CVD; hypertension, silent CVD, stroke, and vascular cognitive impairment [VCI] and co-occurring excess weight and/or diabetes. These conditions and interactions (clusters simultaneously predicted 20 depression items and a latent trait of depression in participants with subsyndromal (including subthreshold depression (11≤ Center for Epidemiologic Studies Depression Scale [CES-D] score ≤27. The option for maximum likelihood estimation with standard errors that are robust to non-normality and non-independence in complex random samples (MLR in Mplus and an innovation created by the author were used for estimating unbiased effects from latent trait models with exhaustive specification. Symptom profiles reveal masked depression in 1 older males, related to the metabolic syndrome (hypertension–overweight–diabetes; silent CVD–overweight; and silent CVD–diabetes and 2 older females or the full sample, related to several diabetes and/or overweight clusters that involve stroke or VCI. Several other disease clusters are equivocal regarding masked depression; a couple do emphasize dysphoric mood. Replicating findings could identify subgroups for cost-effective screening of subsyndromal depression. Keywords: depression, diabetes, overweight, cerebrovascular disease, hypertension, metabolic
Institute of Scientific and Technical Information of China (English)
侯丽英; 朱黎娜; 李婵; 林书祥; 刘堂喻亨; 尹悦; 李会强
2014-01-01
Objective To investigate the allergization of milk high molecular weight proteins. Methods Thirty cas⁃es of patients with serum allergic to milk were selected. Their skin prick tests were positive. Results of serum specific IgE (sIgE) test were positive and≥1+. One case of healthy control with negative sIgE test and without history of allertgy, was in⁃cluded in this study. The serum samples were collected and frozen at-20℃. Sephadex G200 gel chromatography was used to obtain milk high molecular weight proteins. Western blot and ELISA methods were used to detect milk high molecular weight proteins and the activity of serum sIgE. Results Results of SDS-PAGE showed that high molecular weights proteins displayed by Sephadex G200 gel chromatography, mainly including three bands, the molecular weight of 67 ku, 80 ku and 160 ku. Western blot analysis showed that three kinds of high molecular weights proteins can react with milk allergy serum, and the most obvious appeared near the molecular weight 67 ku band. ELISA analysis showed that the positive response rate of high molecular weight proteins with milk allergic patient’s serum was slightly higher than that ofβ-lactoglobulin (46.7%and 43.3%, respectively). Conclusion The milk high molecular weight protein components can induce specific IgE antibod⁃ies, which have important sensitization in the process of milk allergy.%目的：探讨牛奶中高分子质量蛋白在牛奶过敏过程中的致敏作用。方法选取牛奶过敏患者血清30例，皮肤点刺试验阳性，血清特异性IgE（sIgE）检测结果均为阳性且≥1+。健康对照血清1例，血清sIgE检测阴性，无过敏史。空腹采血，收集血清于-20℃冻存备用。利用Sephadex G200凝胶层析获得牛奶高分子质量蛋白，通过蛋白免疫印迹法（Wetern blot）和酶联免疫吸附测定（ELISA）检测高分子质量蛋白与牛奶过敏患者血清sIgE的结合活性。结果 SDS-PAGE显示Sephadex G200凝
Weighted approximation with varying weight
Totik, Vilmos
1994-01-01
A new construction is given for approximating a logarithmic potential by a discrete one. This yields a new approach to approximation with weighted polynomials of the form w"n"(" "= uppercase)P"n"(" "= uppercase). The new technique settles several open problems, and it leads to a simple proof for the strong asymptotics on some L p(uppercase) extremal problems on the real line with exponential weights, which, for the case p=2, are equivalent to power- type asymptotics for the leading coefficients of the corresponding orthogonal polynomials. The method is also modified toyield (in a sense) uniformly good approximation on the whole support. This allows one to deduce strong asymptotics in some L p(uppercase) extremal problems with varying weights. Applications are given, relating to fast decreasing polynomials, asymptotic behavior of orthogonal polynomials and multipoint Pade approximation. The approach is potential-theoretic, but the text is self-contained.
Directory of Open Access Journals (Sweden)
M.ª F. Bernal-Orozco
2010-08-01
Full Text Available Introduction: Body weight is useful for many medical and nutritional procedures. When it is difficult or impossible to measure body weight in hospitalized/institutionalized elderly, it can be estimated through equations based on anthropometry generated in other countries, although their validity in other contexts has been poorly studied. Objectives: To create and validate an equation for estimating body weight for both, hospitalized and nursing home residents Mexican elderly women (institutionalized using anthropometric measurements. Methods: A validation study was carried out in elderly women (≥ 60 years old, admitted to the Geriatrics Service of the Hospital Civil de Guadalajara "Fray Antonio Alcalde" during February-April 19th (n = 43 and April 20th-June 2005 (n = 29, and elderly women residing in three nursing homes in the Metropolitan Area of Guadalajara evaluated during June 2003-June 2004 (n = 23. Subjects were weighed using a scale which was adapted to their clinical situation and were anthropometrically assessed. In the first sample, we generated a new equation using multiple regression analyses. Then, the equation was validated in the other two samples. We also estimated weight using Chumlea's equations: in all samples, estimated and actual weights were compared between each other through a paired t-test. A p Introducción: El peso corporal es útil para llevar a cabo diversos procedimientos médicos y nutrimentales. Cuando se dificulta o es imposible medir el peso corporal en ancianos hospitalizados/institucionalizados, se puede estimar a partir de ecuaciones basadas en antropometría, generadas en otros países, aunque su validez en otros contextos ha sido poco estudiada. Objetivos: Crear y validar una ecuación para estimar peso corporal, tanto en ancianas hospitalizadas, como institucionalizadas en asilos, usando medidas antropométricas. Métodos: Se llevó a cabo un estudio de validación en ancianas (≥ 60 años, admitidas al
McConnel, Craig S; McNeil, Ashleigh A; Hadrich, Joleen C; Lombard, Jason E; Garry, Franklyn B; Heller, Jane
2017-08-01
Over the past 175 years, data related to human disease and death have progressed to a summary measure of population health, the Disability-Adjusted Life Year (DALY). As dairies have intensified there has been no equivalent measure of the impact of disease on the productive life and well-being of animals. The development of a disease-adjusted metric requires a consistent set of disability weights that reflect the relative severity of important diseases. The objective of this study was to use an international survey of dairy authorities to derive disability weights for primary disease categories recorded on dairies. National and international dairy health and management authorities were contacted through professional organizations, dairy industry publications and conferences, and industry contacts. Estimates of minimum, most likely, and maximum disability weights were derived for 12 common dairy cow diseases. Survey participants were asked to estimate the impact of each disease on overall health and milk production. Diseases were classified from 1 (minimal adverse effects) to 10 (death). The data was modelled using BetaPERT distributions to demonstrate the variation in these dynamic disease processes, and to identify the most likely aggregated disability weights for each disease classification. A single disability weight was assigned to each disease using the average of the combined medians for the minimum, most likely, and maximum severity scores. A total of 96 respondents provided estimates of disability weights. The final disability weight values resulted in the following order from least to most severe: retained placenta, diarrhea, ketosis, metritis, mastitis, milk fever, lame (hoof only), calving trauma, left displaced abomasum, pneumonia, musculoskeletal injury (leg, hip, back), and right displaced abomasum. The peaks of the probability density functions indicated that for certain disease states such as retained placenta there was a relatively narrow range of
Directory of Open Access Journals (Sweden)
E. Díaz de León González
2011-10-01
obtener el peso por medición directa en toda la república mexicana y así ajustarlas a cada población en particular.Introduction: The weight is an anthropometric parameter routinely used in ambulatory and hospital settings, and takes its importance, because often there are clinical conditions that impede it´s taking in a traditional scale. There are equations to estimate weight. However, they have not been designed for Mexican ambulatory patients. Objective: To develop an equation to estimate weight in Mexican ambulatory patients from the Study of Health, Well Being and Aging, corresponding to Mexico city an surrounded area. Material and methods: The database of the Study of Health, Well Being and Aging of Mexico City was used, and adults of 60 years and older, who completed the anthropometric measures were included. Two groups of datasets were crated though random numbers, one for the design and the other for the validation of the equation. The equation was obtained from the first database and cross-validated in the second. Results: The equations obtained were: (0.67* (Knee height + (0.46* (Mid-arm circumference + (0.60* (waist circumference + (0.38* (hip circumference + (0.53* (calf circumference - (0.17* (Age in years - 80.01 and (0.69* (Knee height + (0.61* (Mid-arm circumference + (0.17* (waist circumference + (0.45* (hip circumference + (0.58* (calf circumference - (0.24* (Age in years - 55.9 in men and women respectively. The correlation coefficients were 0.94 y 0.92 (p < 0.001 for both. The differences between the real and estimated values were not significant. Conclusion: The equations developed in our analysis were confident and can be employed to estimate weight in ambulatory elderly. It is needed to test its validity in clinical scenarios were it is not possible to weight patients directly in the rest of the Mexican republic and adjust to specific populations.
Institute of Scientific and Technical Information of China (English)
谢敏; 邓佳梁; 刘明波; 李嘉龙; 孙谦; 谭力强
2016-01-01
空调数量增长和极端高温天气使得夏季降温负荷大幅增长，已成为最大负荷屡创新高的重要原因。为了更准确估算降温负荷大小，提出一种基于气象信息和熵权理论的降温负荷估算方法。该方法采用全年最大负荷日负荷曲线与不含降温负荷的基准负荷曲线对应相减后取最大值，从而得到年最大降温负荷。在计算基准负荷曲线时，以气温、相对湿度、降水量等多种气象为轴建立气象坐标系统，通过确定基准气象象限以筛选无降温负荷的基准工作日；根据基准工作日的日最大负荷与气温、相对湿度、降水量等气象信息的相关系数，利用熵权理论确定各基准工作日负荷曲线相对基准负荷曲线权值。最后，利用广州市2009至2013年负荷数据及气象数据估算广州市年最大降温负荷。%Growing quantity of air-conditioners and extremely hot weather has made the temperature-lowing load increase as never before.To estimate temperature-lowering load more accurately,an estimation method based on meteorological data and entropy weight theory is proposed.The maximum value of annual maximum load curve load date less the benchmark curve without temperature-lowering load is annual maximum temperature-lowering load.A meteorological axis system is built based on temperature,relative humidity,precipitation and other meteorological data to determine base meteorological quadrant and filtrate benchmark weekday when calculating base load curve.According to the relevant coefficients between maximum daily load and temperature,relative humidity or precipitation on benchmark weekdays,the weights of benchmark weekday load curves are calculated using the entropy weight theory.Finally,the annual maximum temperature-lowering load is estimated according to Guangzhou 2009—2013 load and meteorological data.The result shows that the new method is more appropriate.
Institute of Scientific and Technical Information of China (English)
潘晓春
2012-01-01
It is necessary to describe the statistical properties of wind speed using three-parameter Weibull distribution for offshore wind energy resource assessment and utilization.According to the functional relation between parameters and probability-weighted moments（PWM）,the functions were fitted with the shape parameter and PWM using logistic curve.Two formulae of parameter estimation were studied out based on low-order insufficient and exceeding PWM.Accuracy test results show that these formulae had higher precision in large-scale range.Through comparative analysis with high-order PWM method for example,the author believes the low-order PWM methods in this paper are worth popularizing.%为便于进行海上风能资源评估与利用,采用三参数Weibull分布来描述风的统计特性是必要的。根据Weibull分布的三参数与概率权重矩（probability-weighted moment,PWM）的关系,应用罗吉斯蒂曲线拟合形状参数与PWM的函数关系,提出低阶不及PWM和超过PWM 2种参数估计方法。精度检验显示,文中方法在较大范围内均具有较高的精度。通过算例分析比较,认为提出的低阶PWM法值得推广使用。
影响西藏南美藜粒重因素的初步研究%A preliminary study on influencing factors of quinoa thousand-grain weight in Tibet
Institute of Scientific and Technical Information of China (English)
白玛群宗; 贡布扎西
2014-01-01
The paper studies Tibetan quinoa , particularly the thousand-grain weight quinoa gathered from Tibet Shigatse Mulin County Emma Heung Pilot land in the past two years .The results show that:1 ) the Tibetan quinoa thousand-grain weight is not related to its color , the plant height , the ear height , the stem height , the ear number , the grain weight , but related to valid branch height;2 ) the mature time makes up the biggest factor for the size and weight of quinoa , with the proportion of big grains being larger in premature qui-noa than in mid-mature or late-mature one;3 ) harvest time also constitutes a big factor affecting the weight of thousand-grain quinoa in that the proportion of big grains of quinoa gathered in September , 2012 is larger than that gathered in 2011 , and the proportion of small grains of quinoa gathered in September 2012 is smaller than that gathered in 2011 , and lots of extremely small grains are found in quinoa gathered in 2011 .%研究了西藏南美藜，特别是通过对近两年在西藏日喀则南木林县艾玛乡试验示范地中采集来的西藏南美藜籽粒千粒重的研究与鉴定发现：（1）西藏南美藜千粒重跟它自身的颜色、株高、穗高、穗数、秆径高、整株重、籽粒重无关，与有效分枝高度有关；（2）西藏早熟南美藜大型籽粒占的比例多于西藏中、晚熟南美藜，西藏早熟南美藜小型籽粒占的比例少于西藏中、晚熟南美藜，即籽粒的早熟或中、晚熟是影响籽粒千粒重的因素；（3）2012年9月采集的西藏南美藜大型籽粒占的比例多于2011年采集的，2012年9月采集的西藏南美藜小型籽粒占的比例少于2011年采集的，2011年采集的西藏南美藜还出现了比例不小的极小型籽粒，即籽粒收获的年限是影响籽粒千粒重的因素。
Preliminary design of pseudo satellites: Basic methods and feasibility criteria
Klimenko, N. N.
2016-12-01
Analytical models of weight and energy balances, aerodynamic models, and solar irradiance models to perform pseudo-satellite preliminary design are presented. Feasibility criteria are determined in accordance with the aim of preliminary design dependent on mission scenario and type of payload.
Directory of Open Access Journals (Sweden)
Maria Marta Martins
2005-02-01
disease, no history of addictions, gemellarity or malformed fetuses. All mothers performed ultrasonographic exams at the 25th and 27th weeks for estimation of the fetal weight. Results: The exams were able to detect the inadequate development of those fetuses small-for-gestational-age group. The cut-off values for echographic fetal weight were established as 775 grams and 1015 grams for the 25th and 27th weeks, respectively A mathematical model was developed, capable of quantifying the probability of newborns exhibiting insufficient intra-uterine growth, being small-for-gestational-age.
Muller, Matthew S.; Bauer, Clarence F.
1994-01-01
Performance of NASA's prototype CELSS Breadboard Project Closed Aquaculture System was evaluated by estimating gas exchange quantification and preliminary carbon and nitrogen balances. The total system oxygen consumption rate was 535 mg/hr kg/fish (cv = 30%) when stocked with Tilapia aurea populations (fresh weights of 97 +/- 19 to 147 +/- 36 g/fish for various trials). Oxygen consumption by T. aurea (260 mg/hr kg/fish) contributed to approximately one-half of total system demand. Continuous carbon dioxide quantification methods were analyzed using the,relation of carbon dioxide to oxygen consumption. Overall food conversion rates averaged 18.2 +/- 3.2%. Major pathways for nitrogen and carbon in the system were described with preliminary mass closure of 60-80% and 60% for nitrogen and carbon.
Are normal-weight adolescents satisfied with their weight?
Directory of Open Access Journals (Sweden)
Mariana Contiero San Martini
Full Text Available ABSTRACT: CONTEXT AND OBJECTIVE: The high prevalence of obesity has led to public policies for combating it. People with normal weight may gain greater awareness of this issue and change their perceptions of their weight. The aim of this study was to evaluate the prevalence of body weight dissatisfaction among normal-weight adolescents, according to demographic and socioeconomic variables, health-related behavior and morbidities. DESIGN AND SETTING: Population-based cross-sectional study that used data from a health survey conducted in the city of Campinas, São Paulo, in 2008-2009. METHODS: The prevalence and prevalence ratios of weight dissatisfaction were estimated according to independent variables, by means of simple and multiple Poisson regression. RESULTS: 573 normal-weight adolescents aged 10 to 19 years (mean age 14.7 years were analyzed. The prevalence of weight dissatisfaction was 43.7% (95% confidence interval, CI: 37.8-49.8. Higher prevalences of weight dissatisfaction were observed among females, individuals aged 15 to 19 years, those whose households had eight or more domestic appliances, former smokers, individuals who reported alcohol intake and those who had one or more chronic diseases. Lower prevalence of dissatisfaction was observed among adolescents living in substandard housing. Among the normal-weight adolescents, 26.1% wished to lose weight and 17.6% wished to gain weight. CONCLUSION: The results from this study indicate that even when weight is seen to be within the normal range, a high proportion of adolescents express dissatisfaction with their weight, especially females, older adolescents and those of higher socioeconomic level.
Institute of Scientific and Technical Information of China (English)
柴华; 梁彦刚; 唐国金
2014-01-01
Under the early warning of two passive satellite-borne sensors,the exponential weighted recursive least square method was applied to the burnout states estimation of ballistic targets.Due to the weighting factor can characterize the local quasi-linearity of the boost phase trajectory of the target,so to some extent the dilemma that generic polynomial cannot handle the whole boost phase of the target can be overcome.Through a dynamic analysis,the kinematic characteristics of boost phase target along the orientation of vertical surface were explored.On that basis,a novel boost phase motion model is proposed,which is more accurate than traditional planar motion model.Simulation results show that the proposed approach is superior to the traditional ones.%在双星预警条件下，将指数加权递归最小二乘算法应用于目标关机点状态估计问题中。通过引入加权因子对目标助推段运动的局部拟线性特性进行描述，从而在一定程度上克服了一般的线性多项式模型难以准确刻画整个助推段运动的难题。通过对助推段目标动力学特性的分析，考察了目标在垂直射面方向上的运动特性。在此基础上，提出了一种更为准确的助推段运动模型。仿真算例表明，所提出的关机点状态估计方法相对于传统的方法具有一定的优越性。
Preliminary Monthly Climatological Summaries
National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary Local Climatological Data, recorded since 1970 on Weather Burean Form 1030 and then National Weather Service Form F-6. The preliminary climate data pages...
Ability Estimation for Conventional Tests.
Kim, Jwa K.; Nicewander, W. Alan
1993-01-01
Bias, standard error, and reliability of five ability estimators were evaluated using Monte Carlo estimates of the unknown conditional means and variances of the estimators. Results indicate that estimates based on Bayesian modal, expected a posteriori, and weighted likelihood estimators were reasonably unbiased with relatively small standard…
Energy Technology Data Exchange (ETDEWEB)
Horger, M., E-mail: marius.horger@med.uni-tuebingen.de [Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str.3, 72076 Tübingen (Germany); Claussen, C., E-mail: cora.claussen@web.de [Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str.3, 72076 Tübingen (Germany); Kramer, U., E-mail: ulrich.kramer@med.uni-tuebingen.de [Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str.3, 72076 Tübingen (Germany); Fenchel, M., E-mail: mfench@yahoo.com [Department of Diagnostic Radiology-Neuraradiology, Eberhard-Karls-University, Hoppe-Seyler-Str.3, 72076 Tübingen (Germany); Lichy, M., E-mail: matthias.lichy@googlemail.com [Siemens Medical Solutions AG, Erlangen, Karl-Schall-Straße 6, 91052 Erlangen (Germany); Kaufmann, S., E-mail: sascha.kaufmann@med.uni-tuebingen.de [Department of Diagnostic Radiology, Eberhard-Karls-University, Hoppe-Seyler-Str.3, 72076 Tübingen (Germany)
2014-09-15
Objective: To assess feasibility of whole-body diffusion-weighted MRI (wbDWI) for very early evaluation of response to therapy in different lymphoma subtypes. Materials and methods: 20 patients (10 male, 10 female; mean age 50.7 ± 16.1 ± 17.2 years) underwent wbDWI (calculation of apparent diffusion coefficient [ADC] with b = 0, 800 s/mm{sup 2}) at baseline and within a median of 7 days after therapy onset. Lymphoma manifestations were evaluated with respect to changes in ADC and size at follow-up with up to six of the largest lesions per patient undergoing quantification. An increase in ADC as well as a decrease in size at follow-up was classified as responder, whereas neither change in ADC nor in size (or progression) was considered non-responder. Results were confirmed at interim measurements (after 3–4 chemotherapy cycles) and 6 months after treatment. Results: 90 lymphoma lesions were analyzed. 18 patients were classified as responders and 2 as non-responder at FU (mean, 1 week). DWI results accurately (100%) correlated with the subsequent interim course of all lesions. {sub mean} {sub baseline} ADC was 0.79 ± 0.28 × 10{sup −3} s/mm{sup 2}. For responders mean {sub follow-up}ADC increased by 64.6 ± 56.5% (p < 0.001) whereas lesions size decreased by mean 14.4 ± 13.3% (p < 0.001). In the non-responder, both values did not significantly change. In patients classified as responders six months after treatment, {sub mean}ADC increase at FU was 70.3 ± 57.8% (p < 0.001) whereas mean size decrease vs. baseline was 15.8 ± 13.6% as compared to non-responders (22.4 ± 39.9%) and 5.4 ± 0.9%, respectively. Conclusion: wbDWI with ADC analysis represents a feasible diagnostic tool for very early response assessment in lymphoma patients enabling also prediction of long-term response.
A Preliminary Study on Models of Root Water Uptake Based on Root Weight%基于根重的作物根系吸水模型初步研究
Institute of Scientific and Technical Information of China (English)
厉玉昇
2014-01-01
作物根系吸水受多种因素影响，笔者在前人研究的基础上，从根系自身生物量变化的角度，依据土壤水动力学原理，构建以根重为因变量的根系吸水模型。采用均方根误差（RMSE）和平均绝对百分误差（MAPE）2个评价指标对模型进行检验和评价。结果表明， RMSE 全年统计的变化范围0.477~1.231， MAPE全年统计的变化范围1.082%~4.052%，平均 RMSE为0.810，平均 MAPE为2.520%，模拟精度基本满足要求。说明建立的根系吸水数值模型及编写的程序具有较高的模拟精度，能够较好地模拟自然条件下作物生长期间的土壤水分动态变化。%Water uptake by crop roots is influenced by many factors. ln this study, on the basis of previous studies, root water uptake models were established with the root weight as a dependent variable from the perspective of root biomass changes according to the theory of soil water dynamics. The established models were verified and evaluated using two indicators: root-mean-square error (RMSE) and mean absolute percentage error (MAPE). The results indicated that the annual variation range of root-mean-square error (RMSE) was 0.477-1.231, with an aver-age of 0.810; the annual variation range of mean absolute percentage error (MAPE) was 1.082%-4.052%, with an average of 2.520%, suggesting that the simulation accuracy basical y met the requirements. The established numerical models of root water uptake and the compiled program exhibit high simulation accuracy, which can perfectly simulate soil water dynamics during the growth period of crops under nat-ural conditions.
WeightLifter: Visual Weight Space Exploration for Multi-Criteria Decision Making.
Pajer, Stephan; Streit, Marc; Torsney-Weir, Thomas; Spechtenhauser, Florian; Muller, Torsten; Piringer, Harald
2017-01-01
A common strategy in Multi-Criteria Decision Making (MCDM) is to rank alternative solutions by weighted summary scores. Weights, however, are often abstract to the decision maker and can only be set by vague intuition. While previous work supports a point-wise exploration of weight spaces, we argue that MCDM can benefit from a regional and global visual analysis of weight spaces. Our main contribution is WeightLifter, a novel interactive visualization technique for weight-based MCDM that facilitates the exploration of weight spaces with up to ten criteria. Our technique enables users to better understand the sensitivity of a decision to changes of weights, to efficiently localize weight regions where a given solution ranks high, and to filter out solutions which do not rank high enough for any plausible combination of weights. We provide a comprehensive requirement analysis for weight-based MCDM and describe an interactive workflow that meets these requirements. For evaluation, we describe a usage scenario of WeightLifter in automotive engineering and report qualitative feedback from users of a deployed version as well as preliminary feedback from decision makers in multiple domains. This feedback confirms that WeightLifter increases both the efficiency of weight-based MCDM and the awareness of uncertainty in the ultimate decisions.
Estimating Bottleneck Bandwidth using TCP
Allman, Mark
1998-01-01
Various issues associated with estimating bottleneck bandwidth using TCP are presented in viewgraph form. Specific topics include: 1) Why TCP is wanted to estimate the bottleneck bandwidth; 2) Setting ssthresh to an appropriate value to reduce loss; 3) Possible packet-pair solutions; and 4) Preliminary results: ACTS and the Internet.
Energy Technology Data Exchange (ETDEWEB)
1982-08-01
This Deliverable No. 18b - Capital and Operating Cost Estimates includes a detailed presentation of the 12,500 BPD coal-to-methanol-to-gasoline plant from the standpoint of capital, preoperations, start-up and operations cost estimation. The base capital cost estimate in June 1982 dollars was prepared by the Ralph M. Parsons Company under the direction of Grace. The escalated capital cost estimate as well as separate estimates for preoperations, startup and operations activities were developed by Grace. The deliverable consists of four volumes. Volume I contains details of methodology used in developing the capital cost estimate, summary information on a base June 1982 capital cost, details of the escalated capital cost estimate and separate sections devoted to preoperations, start-up, and operations cost. The base estimate is supported by detailed information in Volumes II, III and IV. The degree of detail for some units was constrained due to proprietary data. Attempts have been made to exhibit the estimating methodology by including data on individual equipment pricing. Proprietary details are available for inspection upon execution of nondisclosure and/or secrecy agreements with the licensors to whom the data is proprietary. Details of factoring certain pieces of equipment and/or entire modules or units from the 50,000 BPD capital estimate are also included. In the case of the escalated capital estimate, Grace has chosen to include a sensitivity analysis which allows for ready assessment of impacts of escalation rates (inflation), contingency allowances and the construction interest financing rates on the escalated capital cost. Each of the estimates associated with bringing the plant to commercial production rates has as a basis the schedule and engineering documentation found in Deliverable No. 14b - Process Engineering and Mechanical Design Report, No. 28b - Staffing Plans, No. 31b - Construction Plan, and No. 33b - Startup and Operation Plan.
Correlates of Low Birth Weight
Directory of Open Access Journals (Sweden)
Ankur Barua MD, PhD
2014-12-01
Full Text Available Background. Low birth weight is the single most important factor that determines the chances of child survival. A recent annual estimation indicated that nearly 8 million infants are born with low birth weight in India. The infant mortality rate is about 20 times greater for all low birth weight babies. Methods. A matched case–control study was conducted on 130 low birth weight babies and 130 controls for 12 months (from August 1, 2007, to July 31, 2008 at the Central Referral Hospital, Tadong, East District of Sikkim, India. Data were analyzed using the Statistical Package for Social Sciences, version 10.0 for Windows. Chi-square test and multiple logistic regression were applied. A P value less than .05 was considered as significant. Results. In the first phase of this study, 711 newborn babies, borne by 680 mothers, were screened at the Central Referral Hospital of Sikkim during the 1-year study period, and the proportion of low birth weight babies was determined to be 130 (18.3%. Conclusion. Multiple logistic regression analysis, conducted in the second phase, revealed that low or middle socioeconomic status, maternal underweight, twin pregnancy, previous history of delivery of low birth weight babies, smoking and consumption of alcohol during pregnancy, and congenital anomalies had independent significant association with low birth weight in this study population.
Causal Effect Estimation Methods
2014-01-01
Relationship between two popular modeling frameworks of causal inference from observational data, namely, causal graphical model and potential outcome causal model is discussed. How some popular causal effect estimators found in applications of the potential outcome causal model, such as inverse probability of treatment weighted estimator and doubly robust estimator can be obtained by using the causal graphical model is shown. We confine to the simple case of binary outcome and treatment vari...
DEFF Research Database (Denmark)
Jørgensen, Ivan Harald Holger; Bogason, Gudmundur; Bruun, Erik
1995-01-01
This paper proposes a new way to estimate the flow in a micromechanical flow channel. A neural network is used to estimate the delay of random temperature fluctuations induced in a fluid. The design and implementation of a hardware efficient neural flow estimator is described. The system...... is implemented using switched-current technique and is capable of estimating flow in the μl/s range. The neural estimator is built around a multiplierless neural network, containing 96 synaptic weights which are updated using the LMS1-algorithm. An experimental chip has been designed that operates at 5 V...
We know of no studies comparing parent-reported sleep with accelerometer-estimated sleep in their relation to paediatric adiposity. We examined: (i) the reliability of mother-reported sleep compared with accelerometer-estimated sleep; and (ii) the relationship between both sleep measures and child a...
Nevada potential repository preliminary transportation strategy: Study 1
Energy Technology Data Exchange (ETDEWEB)
None,
1995-04-01
Limited feasible options exist when considering the shipment of spent nuclear fuel and high-level radioactive waste. These options are rail or truck; because of the weight associated with transportation casks (68.0 to 113.4 tonnes/75 to 125 tons), heavy-haul trucks are also considered. Yucca Mountain currently lacks rail service or an existing right-of-way for rail; it also lacks a dedicated highway suitable for heavy-haul trucks. Approximately 11,230 shipments by rail are planned from waste producer sites to Nevada, with an additional 1,041 shipments by legal-weight truck from four reactor sites not capable of upgrading for rail shipment. This study identifies the reasonable alternatives for waste transport to the potential repository site, describes the evaluation process performed to identify those alternatives, and discusses the reasons for elimination of transportation routes deemed to be not reasonable. The study concluded that heavy haul truck transportation is feasible-cost is very favorable when compared to rail-but route restrictions must be further evaluated. In addition to restrictions due to seasonal weather conditions, specific routes have additional restrictions, including no travel on holidays or weekends, and travel during daylight hours only. Further restrictions will be imposed by the U.S. Department of Transportation based on routing of radioactive materials by highway. Operation and maintenance costs for heavy-haul over a 24-year period, based on preliminary information, were calculated on an estimated operational cost of $15,000 per trip, with an estimated 468 trips per year average (11,230 total trips), for an estimated cost of $171 million to $173 million, depending on the route used. Because the initial costs and the total system life cycle costs of heavy-haul are approximately 50 percent lower than the lowest rail cost, this option will continue to be evaluated.
... weight) weight loss. As in the treatment with hyperthyroidism, treatment of the abnormal state of hypothyroidism with thyroid ... Goiter Graves’ Disease Graves’ Eye Disease Hashimoto’s Thyroiditis Hyperthyroidism ... & Weight Thyroiditis Thyroid ...
Weight loss surgery helps people with extreme obesity to lose weight. It may be an option if you ... caused by obesity. There are different types of weight loss surgery. They often limit the amount of food ...
Directory of Open Access Journals (Sweden)
Enrique Quevedo García
2012-06-01
Full Text Available Abstract. A study was conducted to determine the variables that estimated the leaf limbo area and the leaf limbo dry weight of peach Prunus persica (L. Batsch cv. Jarillo. Fifty leaves, aged 2.5 months, were selected and measured: leaf limbo length and width, petiole length, leaf length, petiole diameter, leaf limbo fresh weight, petiole fresh weight, leaf fresh weight, leaf limbo dry weight, petiole dry weight, leaf dry weight, length/width limbo, petiole length/limbo length and leaf limbo area. The results allowed to obtain regression equations for estimating the leaf area and the limbo dry weight. Using the lineal models LA = b1 + b2 (LLL x LLW and LA= b1+ b2LLL + b3LLW a leaf area equation was determined. Alternative models to calculate limbo dry weight were evaluated LLDW = -b1+ b2 LLFW and LLDW= - b1 + b2LLL + b3PL. The best equations found with an R2 of 0.99 were LA = 1.572 + 0.65169(LLL x LLW, LA=-23.106+2.8064LLW + 3.6761LLL and LLDW = -0.002+0.401(LLFW.Resumen. Se realizó un estudio para determinar las variables que estimaran el área del limbo foliar y el peso seco del limbo de durazno Prunus persica (L. Batsch cv. Jarillo. Se seleccionaron cincuenta hojas con 2,5 meses de edad, fueron medidos: ancho del limbo, longitud del limbo, longitud del peciolo, longitud hoja, diámetro peciolo, peso fresco del limbo, peso fresco del peciolo, peso fresco de la hoja, peso seco del limbo, peso seco peciolo, peso seco de la hoja, longitud /ancho limbo, longitud del peciolo/longitud del limbo, área foliar del limbo. Los resultados alcanzados permitieron obtener ecuaciones de regresión para estimar el área foliar del limbo y el peso seco del limbo. Se halló una ecuación para la determinación del área foliar del limbo con los modelos lineales LA = b1 + b2 (LLL x LLW y LA= b1 + b2LLL + b3LLW. También se evaluaron modelos alternativas para calcular el peso seco del limbo, LLDW = -b1+ b2LLFW y LLDW= - b1 + b2LLL + b3PL. Las mejores ecuaciones
Evaluation of an artificial intelligence program for estimating occupational exposures.
Johnston, Karen L; Phillips, Margaret L; Esmen, Nurtan A; Hall, Thomas A
2005-03-01
Estimation and Assessment of Substance Exposure (EASE) is an artificial intelligence program developed by UK's Health and Safety Executive to assess exposure. EASE computes estimated airborne concentrations based on a substance's vapor pressure and the types of controls in the work area. Though EASE is intended only to make broad predictions of exposure from occupational environments, some occupational hygienists might attempt to use EASE for individual exposure characterizations. This study investigated whether EASE would accurately predict actual sampling results from a chemical manufacturing process. Personal breathing zone time-weighted average (TWA) monitoring data for two volatile organic chemicals--a common solvent (toluene) and a specialty monomer (chloroprene)--present in this manufacturing process were compared to EASE-generated estimates. EASE-estimated concentrations for specific tasks were weighted by task durations reported in the monitoring record to yield TWA estimates from EASE that could be directly compared to the measured TWA data. Two hundred and six chloroprene and toluene full-shift personal samples were selected from eight areas of this manufacturing process. The Spearman correlation between EASE TWA estimates and measured TWA values was 0.55 for chloroprene and 0.44 for toluene, indicating moderate predictive values for both compounds. For toluene, the interquartile range of EASE estimates at least partially overlapped the interquartile range of the measured data distributions in all process areas. The interquartile range of EASE estimates for chloroprene fell above the interquartile range of the measured data distributions in one process area, partially overlapped the third quartile of the measured data in five process areas and fell within the interquartile range in two process areas. EASE is not a substitute for actual exposure monitoring. However, EASE can be used in conditions that cannot otherwise be sampled and in preliminary
Robust Depth-Weighted Wavelet for Nonparametric Regression Models
Institute of Scientific and Technical Information of China (English)
Lu LIN
2005-01-01
In the nonpaxametric regression models, the original regression estimators including kernel estimator, Fourier series estimator and wavelet estimator are always constructed by the weighted sum of data, and the weights depend only on the distance between the design points and estimation points. As a result these estimators are not robust to the perturbations in data. In order to avoid this problem, a new nonparametric regression model, called the depth-weighted regression model, is introduced and then the depth-weighted wavelet estimation is defined. The new estimation is robust to the perturbations in data, which attains very high breakdown value close to 1/2. On the other hand, some asymptotic behaviours such as asymptotic normality are obtained. Some simulations illustrate that the proposed wavelet estimator is more robust than the original wavelet estimator and, as a price to pay for the robustness, the new method is slightly less efficient than the original method.
Negroni, Jorge A; Lascano, Elena C; Bertolotti, Alejandro M; Gómez, Carmen B; Rodríguez Correa, Carlos A; Favaloro, Roberto R
2010-01-01
Use of a majority of structural variables (age, sex, height) to estimate oxygen consumption in the calculation of cardiac output (CO) by the Fick principle does not account for changes in physiological conditions. To improve this limitation, oxygen consumption was estimated based on the left ventricular pressure-volume area. A pilot study with 10 patients undergoing right cardiac catheterization showed that this approach was successful to estimate CO (r=0,73, vs. thermodilution measured CO). Further essays changing end-diastolic-volume in the pressure-volume area formula by body weight or body surface area showed that this last yielded the best correlation with the thermodilution measured CO (slope=1, ordinate =0.01 and r=0.93). These preliminary results indicate that use of a formula originated from the pressure-volume-area concept is a good alternative to estimate oxygen consumption for CO calculation.
Gastric stimulation for weight loss
Institute of Scientific and Technical Information of China (English)
Meir Mizrahi; Ami Ben Ya'acov; Yaron Ilan
2012-01-01
The prevalence of obesity is growing to epidemic proportions,and there is clearly a need for minimally invasive therapies with few adverse effects that allow for sustained weight loss.Behavior and lifestyle therapy are safe treatments for obesity in the short term,but the durability of the weight loss is limited.Although promising obesity drugs are in development,the currently available drugs lack efficacy or have unacceptable side effects.Surgery leads to long-term weight loss,but it is associated with morbidity and mortality.Gastric electrical stimulation (GES) has received increasing attention as a potential tool for treating obesity and gastrointestinal dysmotility disorders.GES is a promising,minimally invasive,safe,and effective method for treating obesity.External gastric pacing is aimed at alteration of the motility of the gastrointestinal tract in a way that will alter absorption due to alteration of transit time.In addition,data from animal models and preliminary data from human trials suggest a role for the gut-brain axis in the mechanism of GES.This may involve alteration of secretion of hormones associated with hunger or satiety.Patient selection for gastric stimulation therapy seems to be an important determinant of the treatment's outcome.Here,we review the current status,potential mechanisms of action,and possible future applications of gastric stimulation for obesity.
Gastric stimulation for weight loss
Mizrahi, Meir; Ben Ya'acov, Ami; Ilan, Yaron
2012-01-01
The prevalence of obesity is growing to epidemic proportions, and there is clearly a need for minimally invasive therapies with few adverse effects that allow for sustained weight loss. Behavior and lifestyle therapy are safe treatments for obesity in the short term, but the durability of the weight loss is limited. Although promising obesity drugs are in development, the currently available drugs lack efficacy or have unacceptable side effects. Surgery leads to long-term weight loss, but it is associated with morbidity and mortality. Gastric electrical stimulation (GES) has received increasing attention as a potential tool for treating obesity and gastrointestinal dysmotility disorders. GES is a promising, minimally invasive, safe, and effective method for treating obesity. External gastric pacing is aimed at alteration of the motility of the gastrointestinal tract in a way that will alter absorption due to alteration of transit time. In addition, data from animal models and preliminary data from human trials suggest a role for the gut-brain axis in the mechanism of GES. This may involve alteration of secretion of hormones associated with hunger or satiety. Patient selection for gastric stimulation therapy seems to be an important determinant of the treatment’s outcome. Here, we review the current status, potential mechanisms of action, and possible future applications of gastric stimulation for obesity. PMID:22654422
A CLASS OF WEIGHTED WEIBULL DISTRIBUTION
Directory of Open Access Journals (Sweden)
Saman Shahbaz
2010-07-01
Full Text Available The weighted Weibull model is proposed following the method of Azzalini (1985. Basic properties of the distribution; including moments, generating function, hazard rate function and estimation of parameters; have been studied. The weighted Weibull model is proposed following the method of Azzalini (1985. Basic properties of the distribution; including moments, generating function, hazard rate function and estimation of parameters; have been studied.
Institute of Scientific and Technical Information of China (English)
宋宇辰; 刘占宁; 孟海东; 张朋伟
2015-01-01
为了提高资源储量估算的准确性，分析矿石体重取值方法对资源储量估算的影响，提出了一种基于插值方式的矿石体重赋值方法。首先基于某铁铜矿的勘探数据和勘探线剖面图，经过图形格式转换和坐标变换，构建了部分矿体的三维地质模型及地质数据库；其次进行矿石样品组合，采用距离幂次反比法推估矿体品位；然后依据矿石样品体重与品位的测试值，建立了矿石体重与品位的线性、二次、三次及对数回归模型，经过分析比较，确定二次回归模型为矿石体重插值模型；最后在矿体三维地质模型内对矿石体重进行插值并估算储量，分析储量估算结果并与传统矿石体重取值方法估算的资源储量进行比较。结果表明：上述2种方法估算的资源储量相差较小，采用基于插值方式估算的矿石平均品位稍高于传统方法，对于提高资源储量的估算精度具有一定的参考价值。%In order to enhance the accuracy of reserves estimation,analyze the influence of the determination method vol-umetric weight of ore on reserves estimation, a new determination method of volumetric weight of ore based on interpolation method is proposed. Firstly, based on the prospecting data and prospecting line profile maps of an iron & copper mine, by graphics format conversion and coordinate transformation,the three dimensional geological model of part of the orebody of the i-ron &copper and the geological database are established;secondly,the ore samples are grouped,and the distance power inverse ratio method is adopted to estimate the grade of orebody;thirdly,based on the test values of orebody samples weight and grade, the linear regression model,quadratic regression model,cubic regression model and logistic regression model interpolation mod-el of volumetric weight of ore and grade are established. Through analysis and comparison,the quadratic regression
U.S. Geological Survey, Department of the Interior — The water-budget-components geodatabase contains selected data from maps in the,"Selected Approaches to Estimate Water-Budget Components of the High Plains, 1940...
U.S. Geological Survey, Department of the Interior — The water-budget-components geodatabase contains selected data from maps in the,"Selected Approaches to Estimate Water-Budget Components of the High Plains, 1940...
The Effect of Sunspot Weighting
Svalgaard, Leif; Cortesi, Sergio
2015-01-01
Waldmeier in 1947 introduced a weighting (on a scale from 1 to 5) of the sunspot count made at Zurich and its auxiliary station Locarno, whereby larger spots were counted more than once. This counting method inflates the relative sunspot number over that which corresponds to the scale set by Wolfer and Brunner. Svalgaard re-counted some 60,000 sunspots on drawings from the reference station Locarno and determined that the number of sunspots reported were 'over counted' by 44% on average, leading to an inflation (measured by a weight factor) in excess of 1.2 for high solar activity. In a double-blind parallel counting by the Locarno observer Cagnotti, we determined that Svalgaard's count closely matches that of Cagnotti's, allowing us to determine the daily weight factor since 2003 (and sporadically before). We find that a simple empirical equation fits the observed weight factors well, and use that fit to estimate the weight factor for each month back to the introduction of weighting in 1947 and thus to be ab...
Weight loss, weight regain and bone health.
Pines, Amos
2012-08-01
The ideal body image for women these days is being slim but, in the real world, obesity becomes a major health problem even in the developing countries. Overweight, but also underweight, may have associated adverse outcomes in many bodily systems, including the bone. Only a few studies have investigated the consequences of intentional weight loss, then weight regain, on bone metabolism and bone density. It seems that the negative impact of bone loss is not reversed when weight partially rebounds following the end of active intervention programs. Thus the benefits and risks of any weight loss program should be addressed individually, and monitoring of bone parameters is recommended.
Seeing Human Weight from a Single RGB-D Image
Institute of Scientific and Technical Information of China (English)
冯佳时; 颜水成
2014-01-01
Human weight estimation is useful in a variety of potential applications, e.g., targeted advertisement, enter-tainment scenarios and forensic science. However, estimating weight only from color cues is particularly challenging since these cues are quite sensitive to lighting and imaging conditions. In this article, we propose a novel weight estimator based on a single RGB-D image, which utilizes the visual color cues and depth information. Our main contributions are three-fold. First, we construct the W8-RGBD dataset including RGB-D images of different people with ground truth weight. Second, the novel sideview shape feature and the feature fusion model are proposed to facilitate weight estimation. Additionally, we consider gender as another important factor for human weight estimation. Third, we conduct comprehensive experiments using various regression models and feature fusion models on the new weight dataset, and encouraging results are obtained based on the proposed features and models.
Fact Sheet Proven Weight Loss Methods What can weight loss do for you? Losing weight can improve your health in a number of ways. ... limiting calories) usually isn’t enough to cause weight loss. But exercise plays an important part in helping ...
Yasunari, T. J.; Bonasoni, P.; Laj, P.; Fujita, K.; Vuillermoz, E.; Marinoni, A.; Cristofanelli, P.; Duchi, R.; Tartari, G.; Lau, K.-M.
2010-01-01
The possible minimal range of reduction in snow surface albedo due to dry deposition of black carbon (BC) in the pre-monsoon period (March-May) was estimated as a lower bound together with the estimation of its accuracy, based on atmospheric observations at the Nepal Climate Observatory-Pyramid (NCO-P) sited at 5079 m a.s.l. in the Himalayan region. We estimated a total BC deposition rate of 2.89 g m-2 day-1 providing a total deposition of 266 micrograms/ square m for March-May at the site, based on a calculation with a minimal deposition velocity of 1.0 10(exp -4) m/s with atmospheric data of equivalent BC concentration. Main BC size at NCO-P site was determined as 103.1-669.8 nm by correlation analysis between equivalent BC concentration and particulate size distribution in the atmosphere. We also estimated BC deposition from the size distribution data and found that 8.7% of the estimated dry deposition corresponds to the estimated BC deposition from equivalent BC concentration data. If all the BC is deposited uniformly on the top 2-cm pure snow, the corresponding BC concentration is 26.0-68.2 microgram/kg assuming snow density variations of 195-512 kg/ cubic m of Yala Glacier close to NCO-P site. Such a concentration of BC in snow could result in 2.0-5.2% albedo reductions. From a simple numerical calculations and if assuming these albedo reductions continue throughout the year, this would lead to a runoff increases of 70-204 mm of water drainage equivalent of 11.6-33.9% of the annual discharge of a typical Tibetan glacier. Our estimates of BC concentration in snow surface for pre-monsoon season can be considered comparable to those at similar altitude in the Himalayan region, where glaciers and perpetual snow region starts in the vicinity of NCO-P. Our estimates from only BC are likely to represent a lower bound for snow albedo reductions, since a fixed slower deposition velocity was used and atmospheric wind and turbulence effects, snow aging, dust deposition
Snyder, Christopher A.; Acree, Cecil W., Jr.
2012-01-01
A Large Civil Tiltrotor (LCTR) conceptual design was developed as part of the NASA Heavy Lift Rotorcraft Systems Investigation in order to establish a consistent basis for evaluating the benefits of advanced technology for large tiltrotors. The concept has since evolved into the second-generation LCTR2, designed to carry 90 passengers for 1,000 nm at 300 knots, with vertical takeoff and landing capability. This paper performs a preliminary assessment of variable-speed power turbine technology on LCTR2 sizing, while maintaining the same, advanced technology engine core. Six concepts were studied; an advanced, single-speed engine with a conventional power turbine layout (Advanced Conventional Engine, or ACE) using a multi-speed (shifting) gearbox. There were five variable-speed power turbine (VSPT) engine concepts, comprising a matrix of either three or four turbine stages, and fixed or variable guide vanes; plus a minimum weight, twostage, fixed-geometry VSPT. The ACE is the lightest engine, but requires a multi-speed (shifting) gearbox to maximize its fuel efficiency, whereas the VSPT concepts use a lighter, fixed-ratio gearbox. The NASA Design and Analysis of Rotorcraft (NDARC) design code was used to study the trades between rotor and engine efficiency and weight. Rotor performance was determined by Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD II), and engine performance was estimated with the Numerical Propulsion System Simulation (NPSS). Design trades for the ACE vs. VSPT are presented in terms of vehicle gross and empty weight, propulsion system weight and mission fuel burn for the civil mission. Because of its strong effect on gearbox weight and on both rotor and engine efficiency, rotor speed was chosen as the reference design variable for comparing design trades. Major study assumptions are presented and discussed. Impressive engine power-to-weight and fuel efficiency reduced vehicle sensitivity to propulsion system choice
Martinez, Suzanna M; Greenspan, Louise C; Butte, Nancy F; Gregorich, Steven E; De Groat, Cynthia L; Deardorff, Julianna; Penilla, Carlos; Pasch, Lauri A; Flores, Elena; Tschann, Jeanne M
2014-06-01
We know of no studies comparing parent-reported sleep with accelerometer-estimated sleep in their relation to paediatric adiposity. We examined: (i) the reliability of mother-reported sleep compared with accelerometer-estimated sleep; and (ii) the relationship between both sleep measures and child adiposity. The current cross-sectional study included 303 Mexican American mother-child pairs recruited from Kaiser Permanente Northern California. We measured sleep duration using maternal report and accelerometry and child anthropometrics. Concordance between sleep measures was evaluated using the Bland-Altman method. We conducted zero-ordered correlations between mother-reported sleep, accelerometer-estimated sleep and child BMI z-scores (BMIz). Using linear regression, we examined three models to assess child BMIz with mother-reported sleep (model 1), accelerometer-estimated sleep (model 2) and both sleep measures (model 3). Children had an average age of 8.86 years (SD = 0.82). Mothers reported that their child slept 9.81 ± 0.74 h [95% confidence interval (CI): 9.72, 9.89], compared to 9.58 ± 0.71 h (95% CI: 9.50, 9.66) based on accelerometry. Mother-reported sleep and accelerometer-estimated sleep were correlated (r = 0.33, P estimated sleep duration (model 2: β = -0.17; P < 0.01). Accounting for both sleep measures, only accelerometer-measured sleep was related to BMIz (model 3: β = -0.14, P = 0.02). Each sleep measure was related significantly to adiposity, independent of covariates. Accelerometry appeared to be a more reliable measure of children's sleep than maternal report, yet maternal report may be sufficient to examine the sleep-adiposity relationship when resources are limited.
Preliminary risk assessment for nuclear waste disposal in space, volume 1
Rice, E. E.; Denning, R. S.; Friedlander, A. L.
1982-01-01
The feasibility, desirability and preferred approaches for disposal of selected high-level nuclear wastes in space were analyzed. Preliminary space disposal risk estimates and estimates of risk uncertainty are provided.
The TRI preliminary dataset includes the most current TRI data available and reflects toxic chemical releases and pollution prevention activities that occurred at TRI facilities during the 2016 calendar year.