A stereotaxic, population-averaged T1w ovine brain atlas including cerebral morphology and tissue volumes

Directory of Open Access Journals (Sweden)

Björn eNitzsche

2015-06-01

Full Text Available Standard stereotaxic reference systems play a key role in human brain studies. Stereotaxic coordinate systems have also been developed for experimental animals including non-human primates, dogs and rodents. However, they are lacking for other species being relevant in experimental neuroscience including sheep. Here, we present a spatial, unbiased ovine brain template with tissue probability maps (TPM that offer a detailed stereotaxic reference frame for anatomical features and localization of brain areas, thereby enabling inter-individual and cross-study comparability. Three-dimensional data sets from healthy adult Merino sheep (Ovis orientalis aries, 12 ewes and 26 neutered rams were acquired on a 1.5T Philips MRI using a T1w sequence. Data were averaged by linear and non-linear registration algorithms. Moreover, animals were subjected to detailed brain volume analysis including examinations with respect to body weight, age and sex. The created T1w brain template provides an appropriate population-averaged ovine brain anatomy in a spatial standard coordinate system. Additionally, TPM for gray (GM and white (WM matter as well as cerebrospinal fluid (CSF classification enabled automatic prior-based tissue segmentation using statistical parametric mapping (SPM. Overall, a positive correlation of GM volume and body weight explained about 15% of the variance of GM while a positive correlation between WM and age was found. Absolute tissue volume differences were not detected, indeed ewes showed significantly more GM per bodyweight as compared to neutered rams. The created framework including spatial brain template and TPM represent a useful tool for unbiased automatic image preprocessing and morphological characterization in sheep. Therefore, the reported results may serve as a starting point for further experimental and/or translational research aiming at in vivo analysis in this species.

Asymmetric network connectivity using weighted harmonic averages

Science.gov (United States)

Morrison, Greg; Mahadevan, L.

2011-02-01

We propose a non-metric measure of the "closeness" felt between two nodes in an undirected, weighted graph using a simple weighted harmonic average of connectivity, that is a real-valued Generalized Erdös Number (GEN). While our measure is developed with a collaborative network in mind, the approach can be of use in a variety of artificial and real-world networks. We are able to distinguish between network topologies that standard distance metrics view as identical, and use our measure to study some simple analytically tractable networks. We show how this might be used to look at asymmetry in authorship networks such as those that inspired the integer Erdös numbers in mathematical coauthorships. We also show the utility of our approach to devise a ratings scheme that we apply to the data from the NetFlix prize, and find a significant improvement using our method over a baseline.

“Simpson’s paradox” as a manifestation of the properties of weighted average (part 2)

OpenAIRE

Zhekov, Encho

2012-01-01

The article proves that the so-called “Simpson's paradox” is a special case of manifestation of the properties of weighted average. In this case always comes to comparing two weighted averages, where the average of the larger variables is less than that of the smaller. The article demonstrates one method for analyzing the relative change of magnitudes of the type: k S = Σ x iy i i=1 who gives answer to question: what is the reason, the weighted average of few variables with higher values, to ...

“Simpson’s paradox” as a manifestation of the properties of weighted average (part 1)

OpenAIRE

Zhekov, Encho

2012-01-01

The article proves that the so-called “Simpson's paradox” is a special case of manifestation of the properties of weighted average. In this case always comes to comparing two weighted averages, where the average of the larger variables is less than that of the smaller. The article demonstrates one method for analyzing the relative change of magnitudes of the type: S = Σ ki=1x iy i who gives answer to question: what is the reason, the weighted average of few variables with higher values, to be...

Children’s Attitudes and Stereotype Content Toward Thin, Average-Weight, and Overweight Peers

Directory of Open Access Journals (Sweden)

Federica Durante

2014-05-01

Full Text Available Six- to 11-year-old children’s attitudes toward thin, average-weight, and overweight targets were investigated with associated warmth and competence stereotypes. The results showed positive attitudes toward average-weight targets and negative attitudes toward overweight peers: Both attitudes decreased as a function of children’s age. Thin targets were perceived more positively than overweight ones but less positively than average-weight targets. Notably, social desirability concerns predicted the decline of anti-fat bias in older children. Finally, the results showed ambivalent stereotypes toward thin and overweight targets—particularly among older children—mirroring the stereotypes observed in adults. This result suggests that by the end of elementary school, children manage the two fundamental dimensions of social judgment similar to adults.

Three-dimensional computed tomographic angiography to predict weight and volume of deep inferior epigastric artery perforator flap for breast reconstruction.

Science.gov (United States)

Rosson, Gedge D; Shridharani, Sachin M; Magarakis, Michael; Manahan, Michele A; Stapleton, Sahael M; Gilson, Marta M; Flores, Jaime I; Basdag, Basak; Fishman, Elliot K

2011-10-01

Three-dimensional computed tomographic angiography (3D CTA) can be used preoperatively to evaluate the course and caliber of perforating blood vessels for abdominal free-flap breast reconstruction. For postmastectomy breast reconstruction, many women inquire whether the abdominal tissue volume will match that of the breast to be removed. Therefore, our goal was to estimate preoperative volume and weight of the proposed flap and compare them with the actual volume and weight to determine if diagnostic imaging can accurately identify the amount of tissue that could potentially to be harvested. Preoperative 3D CTA was performed in 15 patients, who underwent breast reconstruction using the deep inferior epigastric artery perforator flap. Before each angiogram, stereotactic fiducials were placed on the planned flap outline. The radiologist reviewed each preoperative angiogram to estimate the volume, and thus, weight of the flap. These estimated weights were compared with the actual intraoperative weights. The average estimated weight was 99.7% of the actual weight. The interquartile range (25th to 75th percentile), which represents the "middle half" of the patients, was 91-109%, indicating that half of the patients had an estimated weight within 9% of the actual weight; however, there was a large range (70-133%). 3D CTA with stereotactic fiducials allows surgeons to adequately estimate abdominal flap volume before surgery, potentially giving guidance in the amount of tissue that can be harvested from a patient's lower abdomen. Copyright © 2011 Wiley-Liss, Inc.

A RED modified weighted moving average for soft real-time application

Directory of Open Access Journals (Sweden)

Domanśka Joanna

2014-09-01

Full Text Available The popularity of TCP/IP has resulted in an increase in usage of best-effort networks for real-time communication. Much effort has been spent to ensure quality of service for soft real-time traffic over IP networks. The Internet Engineering Task Force has proposed some architecture components, such as Active Queue Management (AQM. The paper investigates the influence of the weighted moving average on packet waiting time reduction for an AQM mechanism: the RED algorithm. The proposed method for computing the average queue length is based on a difference equation (a recursive equation. Depending on a particular optimality criterion, proper parameters of the modified weighted moving average function can be chosen. This change will allow reducing the number of violations of timing constraints and better use of this mechanism for soft real-time transmissions. The optimization problem is solved through simulations performed in OMNeT++ and later verified experimentally on a Linux implementation

Analisis Prioritas Pembangunan Embung Metode Cluster Analysis, AHP dan Weighted Average (Studi Kasus: Embung di Kabupaten Semarang

Directory of Open Access Journals (Sweden)

Bima Anjasmoro

2016-06-01

Full Text Available The Feasibility study potential of small dams in Semarang District has identified 8 (eight urgent potential small dams. These potential dams here to be constructed within 5 (five years in order to overcome the problem of water shortage in the district. However, the government has limited funding source. It is necessary to select the more urgent small dams to be constructed within the limited budget. The purpose of the research is determining the priority of small dams construction in Semarang District. The method used to determine the priority in this study is cluster analysis, AHP and weighted average method. The criteria used to determine the priority in this study consist of: vegetation in the inundated area, volume of embankment, land acquisition area, useful storage, recervoir life time, water cost/m³, access road to the dam site, land status at abutment and inundated area, construction cost, operation and maintenance cost, irrigation service area and raw water benefit. Based on results of cluster analysis, AHP and weighted average method can be conclude that the priority of small dams construction is 1 Mluweh Small Dam (0.165, 2 Pakis Small Dam (0.142, 3 Lebak Small Dam (0.134, 4 Dadapayam Small Dam (0.128, 5 Gogodalem Small Dam (0.119, 6 Kandangan Small Dam (0.114, 7 Ngrawan Small Dam (0.102 and 8 Jatikurung Small Dam (0.096. Based on analysis of the order of priority of 3 (three method showed that method is more detail than cluster analysis method and weighted average method, because the result of AHP method is closer to the conditions of each dam in the field.

Bivariate copulas on the exponentially weighted moving average control chart

Directory of Open Access Journals (Sweden)

Sasigarn Kuvattana

2016-10-01

Full Text Available This paper proposes four types of copulas on the Exponentially Weighted Moving Average (EWMA control chart when observations are from an exponential distribution using a Monte Carlo simulation approach. The performance of the control chart is based on the Average Run Length (ARL which is compared for each copula. Copula functions for specifying dependence between random variables are used and measured by Kendall’s tau. The results show that the Normal copula can be used for almost all shifts.

Applications of ordered weighted averaging (OWA operators in environmental problems

Directory of Open Access Journals (Sweden)

Carlos Llopis-Albert

2017-04-01

Full Text Available This paper presents an application of a prioritized weighted aggregation operator based on ordered weighted averaging (OWA to deal with stakeholders' constructive participation in water resources projects. They have different degree of acceptance or preference regarding the measures and policies to be carried out, which lead to different environmental and socio-economic outcomes, and hence, to different levels of stakeholders’ satisfaction. The methodology establishes a prioritization relationship upon the stakeholders, which preferences are aggregated by means of weights depending on the satisfaction of the higher priority policy maker. The methodology establishes a prioritization relationship upon the stakeholders, which preferences are aggregated by means of weights depending on the satisfaction of the higher priority policy maker. The methodology has been successfully applied to a Public Participation Project (PPP in watershed management, thus obtaining efficient environmental measures in conflict resolution problems under actors’ preference uncertainties.

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....

VOLUME ESTIMATION, DRY WEIGHT, OIL CONTENT AND QUANTITY OF FENCEPOSTS OF CANDEIA (Eremanthus erythropappus (DC MacLeish

Directory of Open Access Journals (Sweden)

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.

A Divergence Median-based Geometric Detector with A Weighted Averaging Filter

Science.gov (United States)

Hua, Xiaoqiang; Cheng, Yongqiang; Li, Yubo; Wang, Hongqiang; Qin, Yuliang

2018-01-01

To overcome the performance degradation of the classical fast Fourier transform (FFT)-based constant false alarm rate detector with the limited sample data, a divergence median-based geometric detector on the Riemannian manifold of Heimitian positive definite matrices is proposed in this paper. In particular, an autocorrelation matrix is used to model the correlation of sample data. This method of the modeling can avoid the poor Doppler resolution as well as the energy spread of the Doppler filter banks result from the FFT. Moreover, a weighted averaging filter, conceived from the philosophy of the bilateral filtering in image denoising, is proposed and combined within the geometric detection framework. As the weighted averaging filter acts as the clutter suppression, the performance of the geometric detector is improved. Numerical experiments are given to validate the effectiveness of our proposed method.

Analysis of litter size and average litter weight in pigs using a recursive model

DEFF Research Database (Denmark)

Varona, Luis; Sorensen, Daniel; Thompson, Robin

2007-01-01

An analysis of litter size and average piglet weight at birth in Landrace and Yorkshire using a standard two-trait mixed model (SMM) and a recursive mixed model (RMM) is presented. The RMM establishes a one-way link from litter size to average piglet weight. It is shown that there is a one......-to-one correspondence between the parameters of SMM and RMM and that they generate equivalent likelihoods. As parameterized in this work, the RMM tests for the presence of a recursive relationship between additive genetic values, permanent environmental effects, and specific environmental effects of litter size......, on average piglet weight. The equivalent standard mixed model tests whether or not the covariance matrices of the random effects have a diagonal structure. In Landrace, posterior predictive model checking supports a model without any form of recursion or, alternatively, a SMM with diagonal covariance...

The relationship between limit of Dysphagia and average volume per swallow in patients with Parkinson's disease.

Science.gov (United States)

Belo, Luciana Rodrigues; Gomes, Nathália Angelina Costa; Coriolano, Maria das Graças Wanderley de Sales; de Souza, Elizabete Santos; Moura, Danielle Albuquerque Alves; Asano, Amdore Guescel; Lins, Otávio Gomes

2014-08-01

The goal of this study was to obtain the limit of dysphagia and the average volume per swallow in patients with mild to moderate Parkinson's disease (PD) but without swallowing complaints and in normal subjects, and to investigate the relationship between them. We hypothesize there is a direct relationship between these two measurements. The study included 10 patients with idiopathic PD and 10 age-matched normal controls. Surface electromyography was recorded over the suprahyoid muscle group. The limit of dysphagia was obtained by offering increasing volumes of water until piecemeal deglutition occurred. The average volume per swallow was calculated by dividing the time taken by the number of swallows used to drink 100 ml of water. The PD group showed a significantly lower dysphagia limit and lower average volume per swallow. There was a significantly moderate direct correlation and association between the two measurements. About half of the PD patients had an abnormally low dysphagia limit and average volume per swallow, although none had spontaneously related swallowing problems. Both measurements may be used as a quick objective screening test for the early identification of swallowing alterations that may lead to dysphagia in PD patients, but the determination of the average volume per swallow is much quicker and simpler.

Determination of viscosity-average molecular weight of chitosan using intrinsic viscosity measurement

International Nuclear Information System (INIS)

Norzita Yacob; Norhashidah Talip; Maznah Mahmud; Nurul Aizam Idayu Mat Sani; Nor Akma Samsuddin; Norafifah Ahmad Fabillah

2013-01-01

Determination of molecular weight by intrinsic viscosity measurement is a simple method for characterization of chitosan. To study the effect of radiation on molecular weight, chitosan was first irradiated using electron beam at different doses prior to measurement. Different concentrations of chitosan were prepared and measurement was done at room temperature. The flow time data was used to calculate the intrinsic viscosity by extrapolating the reduced viscosity to zero concentration. The value of intrinsic viscosity was then recalculated into the viscosity-average molecular weight using Mark-Houwink equation. (Author)

Determination of Viscosity-Average Molecular Weight of Chitosan using Intrinsic Viscosity Measurement

International Nuclear Information System (INIS)

Norzita Yacob; Norhashidah Talip; Maznah Mahmud

2011-01-01

Molecular weight of chitosan can be determined by different techniques such as Gel Permeation Chromatography (GPC), Static Light Scattering (SLS) and intrinsic viscosity measurement. Determination of molecular weight by intrinsic viscosity measurement is a simple method for characterization of chitosan. Different concentrations of chitosan were prepared and measurement was done at room temperature. The flow time data was used to calculate the intrinsic viscosity by extrapolating the reduced viscosity to zero concentration. The value of intrinsic viscosity was then recalculated into the viscosity-average molecular weight using Mark-Houwink equation. (author)

Determination of average fission fraction produced by 14 MeV neutrons in assemblies with large volume of depleted uranium

International Nuclear Information System (INIS)

Wang Dalun; Li Benci; Wang Xiuchun; Li Yijun; Zhang Shaohua; He Yongwu

1991-07-01

The average fission fraction of 238 U caused by 14 MeV neutrons in assemblies with large volume depleted uranium has been determined. The measured value of p f 238U (R ∞ depleted ) 14 was 0.897 ± 0.036. Measurements were also completed for neutron flux distribution and average fission fraction of 235 U isotope in depleted uranium sphere. Values of p f 238U (R depleted ) have been obtained by using a series of uranium spheres. For a sphere with Φ 600 the p f 23 '8 U (R 300 depleted ) is 0.823 ± 0.041, the density of depleted uranium assembly is 18.8g/cm 3 and total weight of assembly is about 2.8t

Average radiation weighting factors for specific distributed neutron spectra

International Nuclear Information System (INIS)

Ninkovic, M.M.; Raicevic, J.J.

1993-01-01

Spectrum averaged radiation weighting factors for 6 specific neutron fields in the environment of 3 categories of the neutron sources (fission, spontaneous fission and (α,n)) are determined in this paper. Obtained values of these factors are greater 1.5 to 2 times than the corresponding quality factors used for the same purpose until a few years ago. This fact is very important to have in mind in the conversion of the neutron fluence into the neutron dose equivalent. (author)

Derivation of a volume-averaged neutron diffusion equation; Atomos para el desarrollo de Mexico

Energy Technology Data Exchange (ETDEWEB)

Vazquez R, R.; Espinosa P, G. [UAM-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Mexico D.F. 09340 (Mexico); Morales S, Jaime B. [UNAM, Laboratorio de Analisis en Ingenieria de Reactores Nucleares, Paseo Cuauhnahuac 8532, Jiutepec, Morelos 62550 (Mexico)]. e-mail: rvr@xanum.uam.mx

2008-07-01

This paper presents a general theoretical analysis of the problem of neutron motion in a nuclear reactor, where large variations on neutron cross sections normally preclude the use of the classical neutron diffusion equation. A volume-averaged neutron diffusion equation is derived which includes correction terms to diffusion and nuclear reaction effects. A method is presented to determine closure-relationships for the volume-averaged neutron diffusion equation (e.g., effective neutron diffusivity). In order to describe the distribution of neutrons in a highly heterogeneous configuration, it was necessary to extend the classical neutron diffusion equation. Thus, the volume averaged diffusion equation include two corrections factor: the first correction is related with the absorption process of the neutron and the second correction is a contribution to the neutron diffusion, both parameters are related to neutron effects on the interface of a heterogeneous configuration. (Author)

New Internet search volume-based weighting method for integrating various environmental impacts

Energy Technology Data Exchange (ETDEWEB)

Ji, Changyoon, E-mail: changyoon@yonsei.ac.kr; Hong, Taehoon, E-mail: hong7@yonsei.ac.kr

2016-01-15

Weighting is one of the steps in life cycle impact assessment that integrates various characterized environmental impacts as a single index. Weighting factors should be based on the society's preferences. However, most previous studies consider only the opinion of some people. Thus, this research proposes a new weighting method that determines the weighting factors of environmental impact categories by considering public opinion on environmental impacts using the Internet search volumes for relevant terms. To validate the new weighting method, the weighting factors for six environmental impacts calculated by the new weighting method were compared with the existing weighting factors. The resulting Pearson's correlation coefficient between the new and existing weighting factors was from 0.8743 to 0.9889. It turned out that the new weighting method presents reasonable weighting factors. It also requires less time and lower cost compared to existing methods and likewise meets the main requirements of weighting methods such as simplicity, transparency, and reproducibility. The new weighting method is expected to be a good alternative for determining the weighting factor. - Highlight: • A new weighting method using Internet search volume is proposed in this research. • The new weighting method reflects the public opinion using Internet search volume. • The correlation coefficient between new and existing weighting factors is over 0.87. • The new weighting method can present the reasonable weighting factors. • The proposed method can be a good alternative for determining the weighting factors.

New Internet search volume-based weighting method for integrating various environmental impacts

International Nuclear Information System (INIS)

Ji, Changyoon; Hong, Taehoon

2016-01-01

Weighting is one of the steps in life cycle impact assessment that integrates various characterized environmental impacts as a single index. Weighting factors should be based on the society's preferences. However, most previous studies consider only the opinion of some people. Thus, this research proposes a new weighting method that determines the weighting factors of environmental impact categories by considering public opinion on environmental impacts using the Internet search volumes for relevant terms. To validate the new weighting method, the weighting factors for six environmental impacts calculated by the new weighting method were compared with the existing weighting factors. The resulting Pearson's correlation coefficient between the new and existing weighting factors was from 0.8743 to 0.9889. It turned out that the new weighting method presents reasonable weighting factors. It also requires less time and lower cost compared to existing methods and likewise meets the main requirements of weighting methods such as simplicity, transparency, and reproducibility. The new weighting method is expected to be a good alternative for determining the weighting factor. - Highlight: • A new weighting method using Internet search volume is proposed in this research. • The new weighting method reflects the public opinion using Internet search volume. • The correlation coefficient between new and existing weighting factors is over 0.87. • The new weighting method can present the reasonable weighting factors. • The proposed method can be a good alternative for determining the weighting factors.

Liver volume, intrahepatic fat and body weight in the course of a lifestyle interventional study. Analysis with quantitative MR-based methods

International Nuclear Information System (INIS)

Bongers, M.N.; Stefan, N.; Fritsche, A.; Haering, H.U.; Nikolaou, K.; Schick, F.; Machann, J.

2015-01-01

The aim of this study was to investigate potential associations between changes in liver volume, the amount of intrahepatic lipids (IHL) and body weight during lifestyle interventions. In a prospective study 150 patients with an increased risk for developing type 2 diabetes mellitus were included who followed a caloric restriction diet for 6 months. In the retrospective analysis 18 women and 9 men (age range 22-71 years) with an average body mass index (BMI) of 32 kg/m 2 were enrolled. The liver volume was determined at the beginning and after 6 months by three-dimensional magnetic resonance imaging (3D-MRI, echo gradient, opposed-phase) and IHLs were quantified by volume-selective MR spectroscopy in single voxel stimulated echo acquisition mode (STEAM). Univariable and multivariable correlation analyses between changes of liver volume (Δliver volume), intrahepatic lipids (ΔIHL) and body weight (ΔBW) were performed. Univariable correlation analysis in the whole study cohort showed associations between ΔIHL and ΔBW (r = 0.69; p < 0.0001), ΔIHL and Δliver volume (r = 0.66; p = 0.0002) as well as ΔBW and Δliver volume (r = 0.5; p = 0.0073). Multivariable correlation analysis revealed that changes of liver volume are primarily determined by changes in IHL independent of changes in body weight (β = 0.0272; 95 % CI: 0.0155-0.034; p < 0.0001). Changes of liver volume during lifestyle interventions are independent of changes of body weight primarily determined by changes of IHL. These results show the reversibility of augmented liver volume in steatosis if it is possible to reduce IHLs during lifestyle interventions. (orig.) [de

Focused information criterion and model averaging based on weighted composite quantile regression

KAUST Repository

Xu, Ganggang; Wang, Suojin; Huang, Jianhua Z.

2013-01-01

We study the focused information criterion and frequentist model averaging and their application to post-model-selection inference for weighted composite quantile regression (WCQR) in the context of the additive partial linear models. With the non

Effect of various solvents on the viscosity-average molecular weight of poly (vinyl acetate)

International Nuclear Information System (INIS)

Rehman, W.U.; But, M.A.; Chughtai, A.; Jamil, T.; Sattar, A.

2006-01-01

Solution polymerization of Vinyl Acetate was carried out in various solvents (benzene, toluene, ethyl acetate, acetonitrile). Dilute solution viscometry was used to determine the viscosity-average molecular weight of the resulting Poly (Vinyl Acetate) (PV Ac) in each case. The viscosity-average molecular weight (M,J of PVAc was found to increase in the order benzene < toluene < ethyl acetate < acetonitrile, It was concluded that under the same reaction conditions (polymerization time, initiator quantity, solvent/monomer ratio, temperature), acetonitrile served as the best solvent for solution. polymerization of Vinyl Acetate monomer. (author)

Volume-weighted measure for eternal inflation

International Nuclear Information System (INIS)

Winitzki, Sergei

2008-01-01

I propose a new volume-weighted probability measure for cosmological 'multiverse' scenarios involving eternal inflation. The 'reheating-volume (RV) cutoff' calculates the distribution of observable quantities on a portion of the reheating hypersurface that is conditioned to be finite. The RV measure is gauge-invariant, does not suffer from the 'youngness paradox', and is independent of initial conditions at the beginning of inflation. In slow-roll inflationary models with a scalar inflaton, the RV-regulated probability distributions can be obtained by solving nonlinear diffusion equations. I discuss possible applications of the new measure to 'landscape' scenarios with bubble nucleation. As an illustration, I compute the predictions of the RV measure in a simple toy landscape.

Liver volume in thalassaemia major: relationship with body weight, serum ferritin, and liver function

Energy Technology Data Exchange (ETDEWEB)

Chan Yuleung; Law Manyee; Howard, Robert [Chinese University of Hong Kong, Department of Diagnostic Radiology and Organ Imaging, Prince of Wales Hospital, Hong Kong (China); Li Chikong; Chik Kiwai [Chinese University of Hong Kong, Department of Paediatrics, Prince of Wales Hospital, Hong Kong (China)

2005-02-01

It is not known whether body weight alone can adjust for the volume of liver in the calculation of the chelating dose in {beta}-thalassaemia major patients, who frequently have iron overload and hepatitis. The hypothesis is that liver volume in children and adolescents suffering from {beta}-thalassaemia major is affected by ferritin level and liver function. Thirty-five {beta}-thalassaemia major patients aged 7-18 years and 35 age- and sex-matched controls had liver volume measured by MRI. Serum alanine aminotransferase (ALT) and ferritin levels were obtained in the thalassaemia major patients. Body weight explained 65 and 86% of the change in liver volume in {beta}-thalassaemia major patients and age-matched control subjects, respectively. Liver volume/kilogram body weight was significantly higher (P<0.001) in thalassaemia major patients than in control subjects. There was a significant correlation between ALT level and liver volume/kilogram body weight (r=0.55, P=0.001). Patients with elevated ALT had significantly higher liver volume/kilogram body weight (mean 42.9{+-}12 cm{sup 3}/kg) than control subjects (mean 23.4{+-}3.6 cm{sup 3}/kg) and patients with normal ALT levels (mean 27.4{+-}3.6 cm{sup 3}/kg). Body weight is the most important single factor for liver-volume changes in thalassaemia major patients, but elevated ALT also has a significant role. Direct liver volume measurement for chelation dose adjustment may be advantageous in patients with elevated ALT. (orig.)

The impact of using weight estimated from mammographic images vs. self-reported weight on breast cancer risk calculation

Science.gov (United States)

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.

Tree-average distances on certain phylogenetic networks have their weights uniquely determined.

Science.gov (United States)

Willson, Stephen J

2012-01-01

A phylogenetic network N has vertices corresponding to species and arcs corresponding to direct genetic inheritance from the species at the tail to the species at the head. Measurements of DNA are often made on species in the leaf set, and one seeks to infer properties of the network, possibly including the graph itself. In the case of phylogenetic trees, distances between extant species are frequently used to infer the phylogenetic trees by methods such as neighbor-joining. This paper proposes a tree-average distance for networks more general than trees. The notion requires a weight on each arc measuring the genetic change along the arc. For each displayed tree the distance between two leaves is the sum of the weights along the path joining them. At a hybrid vertex, each character is inherited from one of its parents. We will assume that for each hybrid there is a probability that the inheritance of a character is from a specified parent. Assume that the inheritance events at different hybrids are independent. Then for each displayed tree there will be a probability that the inheritance of a given character follows the tree; this probability may be interpreted as the probability of the tree. The tree-average distance between the leaves is defined to be the expected value of their distance in the displayed trees. For a class of rooted networks that includes rooted trees, it is shown that the weights and the probabilities at each hybrid vertex can be calculated given the network and the tree-average distances between the leaves. Hence these weights and probabilities are uniquely determined. The hypotheses on the networks include that hybrid vertices have indegree exactly 2 and that vertices that are not leaves have a tree-child.

Accurate measurement of imaging photoplethysmographic signals based camera using weighted average

Science.gov (United States)

Pang, Zongguang; Kong, Lingqin; Zhao, Yuejin; Sun, Huijuan; Dong, Liquan; Hui, Mei; Liu, Ming; Liu, Xiaohua; Liu, Lingling; Li, Xiaohui; Li, Rongji

2018-01-01

Imaging Photoplethysmography (IPPG) is an emerging technique for the extraction of vital signs of human being using video recordings. IPPG technology with its advantages like non-contact measurement, low cost and easy operation has become one research hot spot in the field of biomedicine. However, the noise disturbance caused by non-microarterial area cannot be removed because of the uneven distribution of micro-arterial, different signal strength of each region, which results in a low signal noise ratio of IPPG signals and low accuracy of heart rate. In this paper, we propose a method of improving the signal noise ratio of camera-based IPPG signals of each sub-region of the face using a weighted average. Firstly, we obtain the region of interest (ROI) of a subject's face based camera. Secondly, each region of interest is tracked and feature-based matched in each frame of the video. Each tracked region of face is divided into 60x60 pixel block. Thirdly, the weights of PPG signal of each sub-region are calculated, based on the signal-to-noise ratio of each sub-region. Finally, we combine the IPPG signal from all the tracked ROI using weighted average. Compared with the existing approaches, the result shows that the proposed method takes modest but significant effects on improvement of signal noise ratio of camera-based PPG estimated and accuracy of heart rate measurement.

Using exponentially weighted moving average algorithm to defend against DDoS attacks

CSIR Research Space (South Africa)

Machaka, P

2016-11-01

Full Text Available This paper seeks to investigate the performance of the Exponentially Weighted Moving Average (EWMA) for mining big data and detection of DDoS attacks in Internet of Things (IoT) infrastructure. The paper will investigate the tradeoff between...

Effect of the averaging volume and algorithm on the in situ electric field for uniform electric- and magnetic-field exposures

International Nuclear Information System (INIS)

Hirata, Akimasa; Takano, Yukinori; Fujiwara, Osamu; Kamimura, Yoshitsugu

2010-01-01

The present study quantified the volume-averaged in situ electric field in nerve tissues of anatomically based numeric Japanese male and female models for exposure to extremely low-frequency electric and magnetic fields. A quasi-static finite-difference time-domain method was applied to analyze this problem. The motivation of our investigation is that the dependence of the electric field induced in nerve tissue on the averaging volume/distance is not clear, while a cubical volume of 5 x 5 x 5 mm 3 or a straight-line segment of 5 mm is suggested in some documents. The influence of non-nerve tissue surrounding nerve tissue is also discussed by considering three algorithms for calculating the averaged in situ electric field in nerve tissue. The computational results obtained herein reveal that the volume-averaged electric field in the nerve tissue decreases with the averaging volume. In addition, the 99th percentile value of the volume-averaged in situ electric field in nerve tissue is more stable than that of the maximal value for different averaging volume. When including non-nerve tissue surrounding nerve tissue in the averaging volume, the resultant in situ electric fields were not so dependent on the averaging volume as compared to the case excluding non-nerve tissue. In situ electric fields averaged over a distance of 5 mm were comparable or larger than that for a 5 x 5 x 5 mm 3 cube depending on the algorithm, nerve tissue considered and exposure scenarios. (note)

Focused information criterion and model averaging based on weighted composite quantile regression

KAUST Repository

Xu, Ganggang

2013-08-13

We study the focused information criterion and frequentist model averaging and their application to post-model-selection inference for weighted composite quantile regression (WCQR) in the context of the additive partial linear models. With the non-parametric functions approximated by polynomial splines, we show that, under certain conditions, the asymptotic distribution of the frequentist model averaging WCQR-estimator of a focused parameter is a non-linear mixture of normal distributions. This asymptotic distribution is used to construct confidence intervals that achieve the nominal coverage probability. With properly chosen weights, the focused information criterion based WCQR estimators are not only robust to outliers and non-normal residuals but also can achieve efficiency close to the maximum likelihood estimator, without assuming the true error distribution. Simulation studies and a real data analysis are used to illustrate the effectiveness of the proposed procedure. © 2013 Board of the Foundation of the Scandinavian Journal of Statistics..

Studies concerning average volume flow and waterpacking anomalies in thermal-hydraulics codes

International Nuclear Information System (INIS)

Lyczkowski, R.W.; Ching, J.T.; Mecham, D.C.

1977-01-01

One-dimensional hydrodynamic codes have been observed to exhibit anomalous behavior in the form of non-physical pressure oscillations and spikes. It is our experience that sometimes this anomaloous behavior can result in mass depletion, steam table failure and in severe cases, problem abortion. In addition, these non-physical pressure spikes can result in long running times when small time steps are needed in an attempt to cope with anomalous solution behavior. The source of these pressure spikes has been conjectured to be caused by nonuniform enthalpy distribution or wave reflection off the closed end of a pipe or abrupt changes in pressure history when the fluid changes from subcooled to two-phase conditions. It is demonstrated in this paper that many of the faults can be attributed to inadequate modeling of the average volume flow and the sharp fluid density front crossing a junction. General corrective models are difficult to devise since the causes of the problems touch on the very theoretical bases of the differential field equations and associated solution scheme. For example, the fluid homogeneity assumption and the numerical extrapolation scheme have placed severe restrictions on the capability of a code to adequately model certain physical phenomena involving fluid discontinuities. The need for accurate junction and local properties to describe phenomena internal to a control volume often points to additional lengthy computations that are difficult to justify in terms of computational efficiency. Corrective models that are economical to implement and use are developed. When incorporated into the one-dimensional, homogeneous transient thermal-hydraulic analysis computer code, RELAP4, they help mitigate many of the code's difficulties related to average volume flow and water-packing anomalies. An average volume flow model and a critical density model are presented. Computational improvements due to these models are also demonstrated

The Effect of Ramadan Fasting and Weight-Lifting Training on Plasma Volume, Glucose and Lipids Profile of Male Weight-Lifters

Directory of Open Access Journals (Sweden)

Seyed Morteza Tayebi

Full Text Available Objective(sThe purpose of the present study was to evaluate the effect of Ramadan fasting and weight-lifting training on plasma volume, glucose, and lipids profile of male weight-lifter.Materials and MethodsForty male weight-lifters were recruited and divided into 4 groups (n=10 each and as the following groups: control (C, fasting (F, training (T and fasting-training (F-T. The T and F-T groups performed weight-lifting technique trainings and hypertrophy body building (3 sessions/week, 90 min/session. All subjects were asked to complete a medical examination as well as a medical questionnaire to ensure that they were not taking any medication, were free of cardiac, respiratory, renal, and metabolic diseases, and were not using steroids. Blood samples were taken at 24 hr before and 24 hr after one month of fasting and weight-lifting exercise. The plasma volume, fasting blood sugar (FBS, lipid profiles, and lipoproteins were analyzed in blood samples. ResultsBody weight and plasma volume showed significant (P< 0.05 decrease and increase in the F group (P< 0.05 respectively. Also, a significant reduction was observed in F-T group body weight (P< 0.01. A significant increase was found in FBS level of F group (P< 0.05. The lipid profiles and lipoproteins didn’t change significantly in C, F, T and the F-T groups.ConclusionThe effect of Ramadan fasting on body weight and plasma volumes may be closely related to the nutritional diet or biochemical response to fasting.

Instantaneous equations for multiphase flow in porous media without length-scale restrictions using a non-local averaging volume

International Nuclear Information System (INIS)

Espinosa-Paredes, Gilberto

2010-01-01

The aim of this paper is to propose a framework to obtain a new formulation for multiphase flow conservation equations without length-scale restrictions, based on the non-local form of the averaged volume conservation equations. The simplification of the local averaging volume of the conservation equations to obtain practical equations is subject to the following length-scale restrictions: d << l << L, where d is the characteristic length of the dispersed phases, l is the characteristic length of the averaging volume, and L is the characteristic length of the physical system. If the foregoing inequality does not hold, or if the scale of the problem of interest is of the order of l, the averaging technique and therefore, the macroscopic theories of multiphase flow should be modified in order to include appropriate considerations and terms in the corresponding equations. In these cases the local form of the averaged volume conservation equations are not appropriate to describe the multiphase system. As an example of the conservation equations without length-scale restrictions, the natural circulation boiling water reactor was consider to study the non-local effects on the thermal-hydraulic core performance during steady-state and transient behaviors, and the results were compared with the classic local averaging volume conservation equations.

Weight and volume estimates for aluminum-air batteries designed for electric vehicle applications

Science.gov (United States)

Cooper, J. F.

1980-01-01

The weights and volumes of reactants, electrolyte, and hardware components are estimated for an aluminum-air battery designed for a 40-kW (peak), 70-kWh aluminum-air battery. Generalized equations are derived which express battery power and energy content as functions of total anode area, aluminum-anode weight, and discharge current density. Equations are also presented which express total battery weight and volume as linear combinations of the variables, anode area and anode weight. The sizing and placement of battery components within the engine compartment of typical five-passenger vehicles is briefly discussed.

The role of haptic versus visual volume cues in the size-weight illusion.

Science.gov (United States)

Ellis, R R; Lederman, S J

1993-03-01

Three experiments establish the size-weight illusion as a primarily haptic phenomenon, despite its having been more traditionally considered an example of vision influencing haptic processing. Experiment 1 documents, across a broad range of stimulus weights and volumes, the existence of a purely haptic size-weight illusion, equal in strength to the traditional illusion. Experiment 2 demonstrates that haptic volume cues are both sufficient and necessary for a full-strength illusion. In contrast, visual volume cues are merely sufficient, and produce a relatively weaker effect. Experiment 3 establishes that congenitally blind subjects experience an effect as powerful as that of blindfolded sighted observers, thus demonstrating that visual imagery is also unnecessary for a robust size-weight illusion. The results are discussed in terms of their implications for both sensory and cognitive theories of the size-weight illusion. Applications of this work to a human factors design and to sensor-based systems for robotic manipulation are also briefly considered.

THE ASSESSMENT OF CORPORATE BONDS ON THE BASIS OF THE WEIGHTED AVERAGE

Directory of Open Access Journals (Sweden)

Victor V. Prokhorov

2014-01-01

Full Text Available The article considers the problem associated with the assessment of the interest rate of a public corporate bond issue. The theme of research is the study of techniques for evaluationof interest rates of corporate bond. The article discusses the task of developing a methodology for assessing the marketinterest rate of corporate bonded loan, which allows to takeinto account the systematic and specific risks. The technique of evaluation of market interest rates of corporate bonds onthe basis of weighted averages is proposed. This procedure uses in the calculation of cumulative barrier interest rate, sectoral weighted average interest rate and the interest ratedetermined on the basis of the model CAPM (Capital Asset Pricing Model. The results, which enable to speak about the possibility of applying the proposed methodology for assessing the market interest rate of a public corporate bond issuein the Russian conditions. The results may be applicable for Russian industrial enterprises, organizing issue public bonds,as well as investment companies exposed organizers of corporate securities loans and other organizations specializingin investments in the Russian public corporate bond loans.

Self-weight effect in the measurement of the volume of silicon spheres

Science.gov (United States)

Mari, D.; Massa, E.; Kuramoto, N.; Mana, G.

2018-04-01

The volume of 28Si spheres about 94 mm in diameter is an input datum for the determination of the Avogadro constant. We report a finite element analysis of the self-weight effect on the volume determination via optical interferometric measurements of the sphere diameters. The self-weight expansion or shrinkage of the equatorial diameters, which ranges from  -31 pm to  +180 pm, depends on the southern latitude of the supports.

Path integral for stochastic inflation: Nonperturbative volume weighting, complex histories, initial conditions, and the end of inflation

Science.gov (United States)

Gratton, Steven

2011-09-01

In this paper we present a path integral formulation of stochastic inflation. Volume weighting can be naturally implemented from this new perspective in a very straightforward way when compared to conventional Langevin approaches. With an in-depth study of inflation in a quartic potential, we investigate how the inflaton evolves and how inflation typically ends both with and without volume weighting. The calculation can be carried to times beyond those accessible to conventional Fokker-Planck approaches. Perhaps unexpectedly, complex histories sometimes emerge with volume weighting. The reward for this excursion into the complex plane is an insight into how volume-weighted inflation both loses memory of initial conditions and ends via slow roll. The slow-roll end of inflation mitigates certain “Youngness Paradox”-type criticisms of the volume-weighted paradigm. Thus it is perhaps time to rehabilitate proper-time volume weighting as a viable measure for answering at least some interesting cosmological questions.

Path integral for stochastic inflation: Nonperturbative volume weighting, complex histories, initial conditions, and the end of inflation

International Nuclear Information System (INIS)

Gratton, Steven

2011-01-01

In this paper we present a path integral formulation of stochastic inflation. Volume weighting can be naturally implemented from this new perspective in a very straightforward way when compared to conventional Langevin approaches. With an in-depth study of inflation in a quartic potential, we investigate how the inflaton evolves and how inflation typically ends both with and without volume weighting. The calculation can be carried to times beyond those accessible to conventional Fokker-Planck approaches. Perhaps unexpectedly, complex histories sometimes emerge with volume weighting. The reward for this excursion into the complex plane is an insight into how volume-weighted inflation both loses memory of initial conditions and ends via slow roll. The slow-roll end of inflation mitigates certain ''Youngness Paradox''-type criticisms of the volume-weighted paradigm. Thus it is perhaps time to rehabilitate proper-time volume weighting as a viable measure for answering at least some interesting cosmological questions.

Effect of Pb-acetate on Testicle Weight and Volume of Mice

Directory of Open Access Journals (Sweden)

Israhnanto Isradji

2011-12-01

Design and Method: Eighty male mice placed in individual cages according to the group. Food and drink provided ad libitum. The treatment of male mice given for 6 weeks. Treatment with 0.2 ml distilled water to PI, P II were given a solution of 400 ppm Pb acetate total of 0.2 ml, P III was given a solution of 1000 ppm Pb acetate as many as 0.2 ml, and P IV were given a solution of 2000 ppm Pb acetate total of 0,2 ml by using a gastric sonde, every morning once a day for 42 days. At week 7, mice were surgery to take the testis. Testicular volume was measured and weighed. Data were analyzed by ANOVA, hypothesis is accepted when p 0.05, testis weight obtained by ANOVA test probability of 0.216 (> 0.05, mean Pb -acetate had no effect on testis weight and volume. Conclusion: Pb-acetate had no effect on testis weight and volume (Sains Medika, 3(2:150-156.

PREPARATION OF ULTRA-LOW VOLUME WEIGHT AUTOCLAVED AERATED CONCRETE

Directory of Open Access Journals (Sweden)

Ondrej Koutny

2016-12-01

Full Text Available Autoclaved aerated concrete is a modern construction material that gains its popularity especially due to its thermal insulation performance resulting from low volume weight and porous structure with sufficient mechanical strength. Nowadays, there are attempts to use this material for thermal insulation purposes and to replace current systems, which have many disadvantages, mainly concerning durability. The key for improvement of thermal insulation properties is therefore obtaining a material based on autoclaved aerated concrete with extremely low volume weight (below 200 kg/m ³ ensuring good thermal isolation properties, but with sufficient mechanical properties to allow easy manipulation. This material can be prepared by foaming very fine powder materials such as silica fume or very finely ground sand. This paper deals with the possibilities of preparation and summarizes the basic requirements for successful preparation of such a material.

Artificial Intelligence Can Predict Daily Trauma Volume and Average Acuity.

Science.gov (United States)

Stonko, David P; Dennis, Bradley M; Betzold, Richard D; Peetz, Allan B; Gunter, Oliver L; Guillamondegui, Oscar D

2018-04-19

The goal of this study was to integrate temporal and weather data in order to create an artificial neural network (ANN) to predict trauma volume, the number of emergent operative cases, and average daily acuity at a level 1 trauma center. Trauma admission data from TRACS and weather data from the National Oceanic and Atmospheric Administration (NOAA) was collected for all adult trauma patients from July 2013-June 2016. The ANN was constructed using temporal (time, day of week), and weather factors (daily high, active precipitation) to predict four points of daily trauma activity: number of traumas, number of penetrating traumas, average ISS, and number of immediate OR cases per day. We trained a two-layer feed-forward network with 10 sigmoid hidden neurons via the Levenberg-Marquardt backpropagation algorithm, and performed k-fold cross validation and accuracy calculations on 100 randomly generated partitions. 10,612 patients over 1,096 days were identified. The ANN accurately predicted the daily trauma distribution in terms of number of traumas, number of penetrating traumas, number of OR cases, and average daily ISS (combined training correlation coefficient r = 0.9018+/-0.002; validation r = 0.8899+/- 0.005; testing r = 0.8940+/-0.006). We were able to successfully predict trauma and emergent operative volume, and acuity using an ANN by integrating local weather and trauma admission data from a level 1 center. As an example, for June 30, 2016, it predicted 9.93 traumas (actual: 10), and a mean ISS score of 15.99 (actual: 13.12); see figure 3. This may prove useful for predicting trauma needs across the system and hospital administration when allocating limited resources. Level III STUDY TYPE: Prognostic/Epidemiological.

Online Self-Organizing Network Control with Time Averaged Weighted Throughput Objective

Directory of Open Access Journals (Sweden)

Zhicong Zhang

2018-01-01

Full Text Available We study an online multisource multisink queueing network control problem characterized with self-organizing network structure and self-organizing job routing. We decompose the self-organizing queueing network control problem into a series of interrelated Markov Decision Processes and construct a control decision model for them based on the coupled reinforcement learning (RL architecture. To maximize the mean time averaged weighted throughput of the jobs through the network, we propose a reinforcement learning algorithm with time averaged reward to deal with the control decision model and obtain a control policy integrating the jobs routing selection strategy and the jobs sequencing strategy. Computational experiments verify the learning ability and the effectiveness of the proposed reinforcement learning algorithm applied in the investigated self-organizing network control problem.

The effect of above average weight gains on the incidence of radiographic bone aberrations and epiphysitis in growing horses

International Nuclear Information System (INIS)

Thompson, K.N.; Jackson, S.G.; Rooney, J.R.

1988-01-01

The relationship between body weight gain and the onset of bone aberrations (e.g. epiphysitis) is described. A model was derived which described the increase in transverse epiphyseal width, and the major factor found to affect epiphyseal width was average daily gain in body weight. In addition, a radiographic examination of the epiphyseal areas showed a larger number of bone aberrations in groups gaining weight at an above-average rate. Thus, a rapid increase in body weight can be suggested as a significant factor in the onset of epiphysitis

Exponentially Weighted Moving Average Chart as a Suitable Tool for Nuchal Translucency Quality Review

Czech Academy of Sciences Publication Activity Database

Hynek, M.; Smetanová, D.; Stejskal, D.; Zvárová, Jana

2014-01-01

Roč. 34, č. 4 (2014), s. 367-376 ISSN 0197-3851 Institutional support: RVO:67985807 Keywords : nuchal translucency * exponentially weighted moving average model * statistics Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 3.268, year: 2014

An inequality between the weighted average and the rowwise correlation coefficient for proximity matrices

NARCIS (Netherlands)

Krijnen, WP

De Vries (1993) discusses Pearson's product-moment correlation, Spearman's rank correlation, and Kendall's rank-correlation coefficient for assessing the association between the rows of two proximity matrices. For each of these he introduces a weighted average variant and a rowwise variant. In this

AN INEQUALITY BETWEEN THE WEIGHTED AVERAGE AND THE ROWWISE CORRELATION-COEFFICIENT FOR PROXIMITY MATRICES

NARCIS (Netherlands)

KRIJNEN, WP

De Vries (1993) discusses Pearson's product-moment correlation, Spearman's rank correlation, and Kendall's rank-correlation coefficient for assessing the association between the rows of two proximity matrices. For each of these he introduces a weighted average variant and a rowwise variant. In this

Analysis of photosynthate translocation velocity and measurement of weighted average velocity in transporting pathway of crops

International Nuclear Information System (INIS)

Ge Cailin; Luo Shishi; Gong Jian; Zhang Hao; Ma Fei

1996-08-01

The translocation profile pattern of 14 C-photosynthate along the transporting pathway in crops were monitored by pulse-labelling a mature leaf with 14 CO 2 . The progressive spreading of translocation profile pattern along the sheath or stem indicates that the translocation of photosynthate along the sheath or stem proceed with a range of velocities rather than with just a single velocity. The method for measuring the weighted average velocity of photosynthate translocation along the sheath or stem was established in living crops. The weighted average velocity and the maximum velocity of photosynthate translocation along the sheath in rice and maize were measured actually. (4 figs., 3 tabs.)

Birth weight and neonatal adiposity prediction using fractional limb volume obtained with 3D ultrasound.

Science.gov (United States)

O'Connor, Clare; O'Higgins, Amy; Doolan, Anne; Segurado, Ricardo; Stuart, Bernard; Turner, Michael J; Kennelly, Máireád M

2014-01-01

The objective of this investigation was to study fetal thigh volume throughout gestation and explore its correlation with birth weight and neonatal body composition. This novel technique may improve birth weight prediction and lead to improved detection rates for fetal growth restriction. Fractional thigh volume (TVol) using 3D ultrasound, fetal biometry and soft tissue thickness were studied longitudinally in 42 mother-infant pairs. The percentages of neonatal body fat, fat mass and fat-free mass were determined using air displacement plethysmography. Correlation and linear regression analyses were performed. Linear regression analysis showed an association between TVol and birth weight. TVol at 33 weeks was also associated with neonatal fat-free mass. There was no correlation between TVol and neonatal fat mass. Abdominal circumference, estimated fetal weight (EFW) and EFW centile showed consistent correlations with birth weight. Thigh volume demonstrated an additional independent contribution to birth weight prediction when added to the EFW centile from the 38-week scan (p = 0.03). Fractional TVol performed at 33 weeks gestation is correlated with birth weight and neonatal lean body mass. This screening test may highlight those at risk of fetal growth restriction or macrosomia.

Inverse optimization of objective function weights for treatment planning using clinical dose-volume histograms

Science.gov (United States)

Babier, Aaron; Boutilier, Justin J.; Sharpe, Michael B.; McNiven, Andrea L.; Chan, Timothy C. Y.

2018-05-01

We developed and evaluated a novel inverse optimization (IO) model to estimate objective function weights from clinical dose-volume histograms (DVHs). These weights were used to solve a treatment planning problem to generate ‘inverse plans’ that had similar DVHs to the original clinical DVHs. Our methodology was applied to 217 clinical head and neck cancer treatment plans that were previously delivered at Princess Margaret Cancer Centre in Canada. Inverse plan DVHs were compared to the clinical DVHs using objective function values, dose-volume differences, and frequency of clinical planning criteria satisfaction. Median differences between the clinical and inverse DVHs were within 1.1 Gy. For most structures, the difference in clinical planning criteria satisfaction between the clinical and inverse plans was at most 1.4%. For structures where the two plans differed by more than 1.4% in planning criteria satisfaction, the difference in average criterion violation was less than 0.5 Gy. Overall, the inverse plans were very similar to the clinical plans. Compared with a previous inverse optimization method from the literature, our new inverse plans typically satisfied the same or more clinical criteria, and had consistently lower fluence heterogeneity. Overall, this paper demonstrates that DVHs, which are essentially summary statistics, provide sufficient information to estimate objective function weights that result in high quality treatment plans. However, as with any summary statistic that compresses three-dimensional dose information, care must be taken to avoid generating plans with undesirable features such as hotspots; our computational results suggest that such undesirable spatial features were uncommon. Our IO-based approach can be integrated into the current clinical planning paradigm to better initialize the planning process and improve planning efficiency. It could also be embedded in a knowledge-based planning or adaptive radiation therapy framework to

Average weighted receiving time in recursive weighted Koch networks

Indian Academy of Sciences (India)

Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 6 ... Nonlinear Scientific Research Center, Faculty of Science, Jiangsu University, Zhenjiang, Jiangsu, 212013, People's Republic of China; School of Computer Science and Telecommunication Engineering, Jiangsu University, Zhenjiang, 212013, People's ...

Models for predicting objective function weights in prostate cancer IMRT

International Nuclear Information System (INIS)

Boutilier, Justin J.; Lee, Taewoo; Craig, Tim; Sharpe, Michael B.; Chan, Timothy C. Y.

2015-01-01

Purpose: To develop and evaluate the clinical applicability of advanced machine learning models that simultaneously predict multiple optimization objective function weights from patient geometry for intensity-modulated radiation therapy of prostate cancer. Methods: A previously developed inverse optimization method was applied retrospectively to determine optimal objective function weights for 315 treated patients. The authors used an overlap volume ratio (OV) of bladder and rectum for different PTV expansions and overlap volume histogram slopes (OVSR and OVSB for the rectum and bladder, respectively) as explanatory variables that quantify patient geometry. Using the optimal weights as ground truth, the authors trained and applied three prediction models: logistic regression (LR), multinomial logistic regression (MLR), and weighted K-nearest neighbor (KNN). The population average of the optimal objective function weights was also calculated. Results: The OV at 0.4 cm and OVSR at 0.1 cm features were found to be the most predictive of the weights. The authors observed comparable performance (i.e., no statistically significant difference) between LR, MLR, and KNN methodologies, with LR appearing to perform the best. All three machine learning models outperformed the population average by a statistically significant amount over a range of clinical metrics including bladder/rectum V53Gy, bladder/rectum V70Gy, and dose to the bladder, rectum, CTV, and PTV. When comparing the weights directly, the LR model predicted bladder and rectum weights that had, on average, a 73% and 74% relative improvement over the population average weights, respectively. The treatment plans resulting from the LR weights had, on average, a rectum V70Gy that was 35% closer to the clinical plan and a bladder V70Gy that was 29% closer, compared to the population average weights. Similar results were observed for all other clinical metrics. Conclusions: The authors demonstrated that the KNN and MLR

Models for predicting objective function weights in prostate cancer IMRT

Energy Technology Data Exchange (ETDEWEB)

Boutilier, Justin J., E-mail: j.boutilier@mail.utoronto.ca; Lee, Taewoo [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario M5S 3G8 (Canada); Craig, Tim [Radiation Medicine Program, UHN Princess Margaret Cancer Centre, 610 University of Avenue, Toronto, Ontario M5T 2M9, Canada and Department of Radiation Oncology, University of Toronto, 148 - 150 College Street, Toronto, Ontario M5S 3S2 (Canada); Sharpe, Michael B. [Radiation Medicine Program, UHN Princess Margaret Cancer Centre, 610 University of Avenue, Toronto, Ontario M5T 2M9 (Canada); Department of Radiation Oncology, University of Toronto, 148 - 150 College Street, Toronto, Ontario M5S 3S2 (Canada); Techna Institute for the Advancement of Technology for Health, 124 - 100 College Street, Toronto, Ontario M5G 1P5 (Canada); Chan, Timothy C. Y. [Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario M5S 3G8, Canada and Techna Institute for the Advancement of Technology for Health, 124 - 100 College Street, Toronto, Ontario M5G 1P5 (Canada)

2015-04-15

Purpose: To develop and evaluate the clinical applicability of advanced machine learning models that simultaneously predict multiple optimization objective function weights from patient geometry for intensity-modulated radiation therapy of prostate cancer. Methods: A previously developed inverse optimization method was applied retrospectively to determine optimal objective function weights for 315 treated patients. The authors used an overlap volume ratio (OV) of bladder and rectum for different PTV expansions and overlap volume histogram slopes (OVSR and OVSB for the rectum and bladder, respectively) as explanatory variables that quantify patient geometry. Using the optimal weights as ground truth, the authors trained and applied three prediction models: logistic regression (LR), multinomial logistic regression (MLR), and weighted K-nearest neighbor (KNN). The population average of the optimal objective function weights was also calculated. Results: The OV at 0.4 cm and OVSR at 0.1 cm features were found to be the most predictive of the weights. The authors observed comparable performance (i.e., no statistically significant difference) between LR, MLR, and KNN methodologies, with LR appearing to perform the best. All three machine learning models outperformed the population average by a statistically significant amount over a range of clinical metrics including bladder/rectum V53Gy, bladder/rectum V70Gy, and dose to the bladder, rectum, CTV, and PTV. When comparing the weights directly, the LR model predicted bladder and rectum weights that had, on average, a 73% and 74% relative improvement over the population average weights, respectively. The treatment plans resulting from the LR weights had, on average, a rectum V70Gy that was 35% closer to the clinical plan and a bladder V70Gy that was 29% closer, compared to the population average weights. Similar results were observed for all other clinical metrics. Conclusions: The authors demonstrated that the KNN and MLR

Analysis and Design of Improved Weighted Average Current Control Strategy for LCL-Type Grid-Connected Inverters

DEFF Research Database (Denmark)

Han, Yang; Li, Zipeng; Yang, Ping

2017-01-01

The LCL grid-connected inverter has the ability to attenuate the high-frequency current harmonics. However, the inherent resonance of the LCL filter affects the system stability significantly. To damp the resonance effect, the dual-loop current control can be used to stabilize the system. The grid...... Control Strategy for LCL-Type Grid-Connected Inverters. Available from: https://www.researchgate.net/publication/313734269_Analysis_and_Design_of_Improved_Weighted_Average_Current_Control_Strategy_for_LCL-Type_Grid-Connected_Inverters [accessed Apr 20, 2017]....... current plus capacitor current feedback system is widely used for its better transient response and high robustness against the grid impedance variations. While the weighted average current (WAC) feedback scheme is capable to provide a wider bandwidth at higher frequencies but show poor stability...

NMR measurement of dynamic nuclear polarization: a technique to test the quality of its volume average obtained with different NMR coil configurations

International Nuclear Information System (INIS)

Zhao, W.H.; Cox, S.F.J.

1980-07-01

In the NMR measurement of dynamic nuclear polarization, a volume average is obtained where the contribution from different parts of the sample is weighted according to the local intensity of the RF field component perpendicular to the large static field. A method of mapping this quantity is described. A small metallic object whose geometry is chosen to perturb the appropriate RF component is scanned through the region to be occupied by the sample. The response of the phase angle of the impedance of a tuned circuit comprising the NMR coil gives a direct measurement of the local weighting factor. The correlation between theory and experiment was obtained by using a circular coil. The measuring method, checked in this way, was then used to investigate the field profiles of practical coils which are required to be rectangular for a proposed experimental neutron polarizing filter. This method can be used to evaluate other practical RF coils. (author)

Volume-weighted particle-tracking method for solute-transport modeling; Implementation in MODFLOW–GWT

Science.gov (United States)

Winston, Richard B.; Konikow, Leonard F.; Hornberger, George Z.

2018-02-16

In the traditional method of characteristics for groundwater solute-transport models, advective transport is represented by moving particles that track concentration. This approach can lead to global mass-balance problems because in models of aquifers having complex boundary conditions and heterogeneous properties, particles can originate in cells having different pore volumes and (or) be introduced (or removed) at cells representing fluid sources (or sinks) of varying strengths. Use of volume-weighted particles means that each particle tracks solute mass. In source or sink cells, the changes in particle weights will match the volume of water added or removed through external fluxes. This enables the new method to conserve mass in source or sink cells as well as globally. This approach also leads to potential efficiencies by allowing the number of particles per cell to vary spatially—using more particles where concentration gradients are high and fewer where gradients are low. The approach also eliminates the need for the model user to have to distinguish between “weak” and “strong” fluid source (or sink) cells. The new model determines whether solute mass added by fluid sources in a cell should be represented by (1) new particles having weights representing appropriate fractions of the volume of water added by the source, or (2) distributing the solute mass added over all particles already in the source cell. The first option is more appropriate for the condition of a strong source; the latter option is more appropriate for a weak source. At sinks, decisions whether or not to remove a particle are replaced by a reduction in particle weight in proportion to the volume of water removed. A number of test cases demonstrate that the new method works well and conserves mass. The method is incorporated into a new version of the U.S. Geological Survey’s MODFLOW–GWT solute-transport model.

Modified Exponential Weighted Moving Average (EWMA) Control Chart on Autocorrelation Data

Science.gov (United States)

Herdiani, Erna Tri; Fandrilla, Geysa; Sunusi, Nurtiti

2018-03-01

In general, observations of the statistical process control are assumed to be mutually independence. However, this assumption is often violated in practice. Consequently, statistical process controls were developed for interrelated processes, including Shewhart, Cumulative Sum (CUSUM), and exponentially weighted moving average (EWMA) control charts in the data that were autocorrelation. One researcher stated that this chart is not suitable if the same control limits are used in the case of independent variables. For this reason, it is necessary to apply the time series model in building the control chart. A classical control chart for independent variables is usually applied to residual processes. This procedure is permitted provided that residuals are independent. In 1978, Shewhart modification for the autoregressive process was introduced by using the distance between the sample mean and the target value compared to the standard deviation of the autocorrelation process. In this paper we will examine the mean of EWMA for autocorrelation process derived from Montgomery and Patel. Performance to be investigated was investigated by examining Average Run Length (ARL) based on the Markov Chain Method.

VOLUME ESTIMATIONS FOR COMBINED FREE-WEIGHT AND RUBBER-BAND RESISTANCE EXERCISE

OpenAIRE

C. Shoepe, Todd; Vejarano, Gustavo; P. Reyes, Nathan; M. Gobreial, Nicole; M. Ricci, Jeanette

2017-01-01

Volume, or the total work performed during resistance training is one of the vital variables of resistance exercise programming. The most common definition in use by practitioners is sets x reps x external weight. While appropriate for linear loading incurred through free-weight resistance exercise, this inadequately addresses the nonlinear loading incurred with rubber resistance, a relatively new loading technique. The purpose of this investigation was to derive a theoretical model to descri...

Normal gray and white matter volume after weight restoration in adolescents with anorexia nervosa.

Science.gov (United States)

Lázaro, Luisa; Andrés, Susana; Calvo, Anna; Cullell, Clàudia; Moreno, Elena; Plana, M Teresa; Falcón, Carles; Bargalló, Núria; Castro-Fornieles, Josefina

2013-12-01

The aim of this study was to determine whether treated, weight-stabilized adolescents with anorexia nervosa (AN) present brain volume differences in comparison with healthy controls. Thirty-five adolescents with weight-recovered AN and 17 healthy controls were assessed by means of psychopathology scales and magnetic resonance imaging. Axial three-dimensional T1-weighted images were obtained in a 1.5 Tesla scanner and analyzed using optimized voxel-based morphometry (VBM). There were no significant differences between controls and weight-stabilized AN patients with regard to global volumes of either gray or white brain matter, or in the regional VBM study. Differences were not significant between patients with psychopharmacological treatment and without, between those with amenorrhea and without, as well as between patients with restrictive versus purgative AN. The present findings reveal no global or regional gray or white matter abnormalities in this sample of adolescents following weight restoration. Copyright © 2013 Wiley Periodicals, Inc.

Greater-than-Class C low-level waste characterization. Appendix I: Impact of concentration averaging low-level radioactive waste volume projections

International Nuclear Information System (INIS)

Tuite, P.; Tuite, K.; O'Kelley, M.; Ely, P.

1991-08-01

This study provides a quantitative framework for bounding unpackaged greater-than-Class C low-level radioactive waste types as a function of concentration averaging. The study defines the three concentration averaging scenarios that lead to base, high, and low volumetric projections; identifies those waste types that could be greater-than-Class C under the high volume, or worst case, concentration averaging scenario; and quantifies the impact of these scenarios on identified waste types relative to the base case scenario. The base volume scenario was assumed to reflect current requirements at the disposal sites as well as the regulatory views. The high volume scenario was assumed to reflect the most conservative criteria as incorporated in some compact host state requirements. The low volume scenario was assumed to reflect the 10 CFR Part 61 criteria as applicable to both shallow land burial facilities and to practices that could be employed to reduce the generation of Class C waste types

The difference between alternative averages

Directory of Open Access Journals (Sweden)

James Vaupel

2012-09-01

Full Text Available BACKGROUND Demographers have long been interested in how compositional change, e.g., change in age structure, affects population averages. OBJECTIVE We want to deepen understanding of how compositional change affects population averages. RESULTS The difference between two averages of a variable, calculated using alternative weighting functions, equals the covariance between the variable and the ratio of the weighting functions, divided by the average of the ratio. We compare weighted and unweighted averages and also provide examples of use of the relationship in analyses of fertility and mortality. COMMENTS Other uses of covariances in formal demography are worth exploring.

Multi-criteria, personalized route planning using quantifier-guided ordered weighted averaging operators

Science.gov (United States)

Nadi, S.; Delavar, M. R.

2011-06-01

This paper presents a generic model for using different decision strategies in multi-criteria, personalized route planning. Some researchers have considered user preferences in navigation systems. However, these prior studies typically employed a high tradeoff decision strategy, which used a weighted linear aggregation rule, and neglected other decision strategies. The proposed model integrates a pairwise comparison method and quantifier-guided ordered weighted averaging (OWA) aggregation operators to form a personalized route planning method that incorporates different decision strategies. The model can be used to calculate the impedance of each link regarding user preferences in terms of the route criteria, criteria importance and the selected decision strategy. Regarding the decision strategy, the calculated impedance lies between aggregations that use a logical "and" (which requires all the criteria to be satisfied) and a logical "or" (which requires at least one criterion to be satisfied). The calculated impedance also includes taking the average of the criteria scores. The model results in multiple alternative routes, which apply different decision strategies and provide users with the flexibility to select one of them en-route based on the real world situation. The model also defines the robust personalized route under different decision strategies. The influence of different decision strategies on the results are investigated in an illustrative example. This model is implemented in a web-based geographical information system (GIS) for Isfahan in Iran and verified in a tourist routing scenario. The results demonstrated, in real world situations, the validity of the route planning carried out in the model.

An Exponentially Weighted Moving Average Control Chart for Bernoulli Data

DEFF Research Database (Denmark)

Spliid, Henrik

2010-01-01

of the transformation is given and its limit for small values of p is derived. Control of high yield processes is discussed and the chart is shown to perform very well in comparison with both the most common alternative EWMA chart and the CUSUM chart. The construction and the use of the proposed EWMA chart......We consider a production process in which units are produced in a sequential manner. The units can, for example, be manufactured items or services, provided to clients. Each unit produced can be a failure with probability p or a success (non-failure) with probability (1-p). A novel exponentially...... weighted moving average (EWMA) control chart intended for surveillance of the probability of failure, p, is described. The chart is based on counting the number of non-failures produced between failures in combination with a variance-stabilizing transformation. The distribution function...

Calculation of weighted averages approach for the estimation of ping tolerance values

Science.gov (United States)

Silalom, S.; Carter, J.L.; Chantaramongkol, P.

2010-01-01

A biotic index was created and proposed as a tool to assess water quality in the Upper Mae Ping sub-watersheds. The Ping biotic index was calculated by utilizing Ping tolerance values. This paper presents the calculation of Ping tolerance values of the collected macroinvertebrates. Ping tolerance values were estimated by a weighted averages approach based on the abundance of macroinvertebrates and six chemical constituents that include conductivity, dissolved oxygen, biochemical oxygen demand, ammonia nitrogen, nitrate nitrogen and orthophosphate. Ping tolerance values range from 0 to 10. Macroinvertebrates assigned a 0 are very sensitive to organic pollution while macroinvertebrates assigned 10 are highly tolerant to pollution.

Fuzzy weighted average based on left and right scores in Malaysia tourism industry

Science.gov (United States)

Kamis, Nor Hanimah; Abdullah, Kamilah; Zulkifli, Muhammad Hazim; Sahlan, Shahrazali; Mohd Yunus, Syaizzal

2013-04-01

Tourism is known as an important sector to the Malaysian economy including economic generator, creating business and job offers. It is reported to bring in almost RM30 billion of the national income, thanks to intense worldwide promotion by Tourism Malaysia. One of the well-known attractions in Malaysia is our beautiful islands. The islands continue to be developed into tourist spots and attracting a continuous number of tourists. Chalets, luxury bungalows and resorts quickly develop along the coastlines of popular islands like Tioman, Redang, Pangkor, Perhentian, Sibu and so many others. In this study, we applied Fuzzy Weighted Average (FWA) method based on left and right scores in order to determine the criteria weights and to select the best island in Malaysia. Cost, safety, attractive activities, accommodation and scenery are five main criteria to be considered and five selected islands in Malaysia are taken into accounts as alternatives. The most important criteria that have been considered by the tourist are defined based on criteria weights ranking order and the best island in Malaysia is then determined in terms of FWA values. This pilot study can be used as a reference to evaluate performances or solving any selection problems, where more criteria, alternatives and decision makers will be considered in the future.

CT- and MRI-based volumetry of resected liver specimen: Comparison to intraoperative volume and weight measurements and calculation of conversion factors

International Nuclear Information System (INIS)

Karlo, C.; Reiner, C.S.; Stolzmann, P.; Breitenstein, S.; Marincek, B.; Weishaupt, D.; Frauenfelder, T.

2010-01-01

Objective: To compare virtual volume to intraoperative volume and weight measurements of resected liver specimen and calculate appropriate conversion factors to reach better correlation. Methods: Preoperative (CT-group, n = 30; MRI-group, n = 30) and postoperative MRI (n = 60) imaging was performed in 60 patients undergoing partial liver resection. Intraoperative volume and weight of the resected liver specimen was measured. Virtual volume measurements were performed by two readers (R1,R2) using dedicated software. Conversion factors were calculated. Results: Mean intraoperative resection weight/volume: CT: 855 g/852 mL; MRI: 872 g/860 mL. Virtual resection volume: CT: 960 mL(R1), 982 mL(R2); MRI: 1112 mL(R1), 1115 mL(R2). Strong positive correlation for both readers between intraoperative and virtual measurements, mean of both readers: CT: R = 0.88(volume), R = 0.89(weight); MRI: R = 0.95(volume), R = 0.92(weight). Conversion factors: 0.85(CT), 0.78(MRI). Conclusion: CT- or MRI-based volumetry of resected liver specimen is accurate and recommended for preoperative planning. A conversion of the result is necessary to improve intraoperative and virtual measurement correlation. We found 0.85 for CT- and 0.78 for MRI-based volumetry the most appropriate conversion factors.

Gamma-Weighted Discrete Ordinate Two-Stream Approximation for Computation of Domain Averaged Solar Irradiance

Science.gov (United States)

Kato, S.; Smith, G. L.; Barker, H. W.

2001-01-01

An algorithm is developed for the gamma-weighted discrete ordinate two-stream approximation that computes profiles of domain-averaged shortwave irradiances for horizontally inhomogeneous cloudy atmospheres. The algorithm assumes that frequency distributions of cloud optical depth at unresolved scales can be represented by a gamma distribution though it neglects net horizontal transport of radiation. This algorithm is an alternative to the one used in earlier studies that adopted the adding method. At present, only overcast cloudy layers are permitted.

Long-Term Prediction of Emergency Department Revenue and Visitor Volume Using Autoregressive Integrated Moving Average Model

Directory of Open Access Journals (Sweden)

Chieh-Fan Chen

2011-01-01

Full Text Available This study analyzed meteorological, clinical and economic factors in terms of their effects on monthly ED revenue and visitor volume. Monthly data from January 1, 2005 to September 30, 2009 were analyzed. Spearman correlation and cross-correlation analyses were performed to identify the correlation between each independent variable, ED revenue, and visitor volume. Autoregressive integrated moving average (ARIMA model was used to quantify the relationship between each independent variable, ED revenue, and visitor volume. The accuracies were evaluated by comparing model forecasts to actual values with mean absolute percentage of error. Sensitivity of prediction errors to model training time was also evaluated. The ARIMA models indicated that mean maximum temperature, relative humidity, rainfall, non-trauma, and trauma visits may correlate positively with ED revenue, but mean minimum temperature may correlate negatively with ED revenue. Moreover, mean minimum temperature and stock market index fluctuation may correlate positively with trauma visitor volume. Mean maximum temperature, relative humidity and stock market index fluctuation may correlate positively with non-trauma visitor volume. Mean maximum temperature and relative humidity may correlate positively with pediatric visitor volume, but mean minimum temperature may correlate negatively with pediatric visitor volume. The model also performed well in forecasting revenue and visitor volume.

Adaptive polarization image fusion based on regional energy dynamic weighted average

Institute of Scientific and Technical Information of China (English)

ZHAO Yong-qiang; PAN Quan; ZHANG Hong-cai

2005-01-01

According to the principle of polarization imaging and the relation between Stokes parameters and the degree of linear polarization, there are much redundant and complementary information in polarized images. Since man-made objects and natural objects can be easily distinguished in images of degree of linear polarization and images of Stokes parameters contain rich detailed information of the scene, the clutters in the images can be removed efficiently while the detailed information can be maintained by combining these images. An algorithm of adaptive polarization image fusion based on regional energy dynamic weighted average is proposed in this paper to combine these images. Through an experiment and simulations,most clutters are removed by this algorithm. The fusion method is used for different light conditions in simulation, and the influence of lighting conditions on the fusion results is analyzed.

A SURVEY OF SIZES AND WEIGHTS OF BEMISIA TABACI（HOMOPTERA： ALEYRODIDAE）B BIOTYPE LIFE STAGES FROM FIELD GROWN COTTON AND CANTALOUPES

Institute of Scientific and Technical Information of China (English)

Chang-chiChu; JamesS.Buckner; KamilKarut; ThomasP.Freeman; DennisR.Nelson; ThomasJ.Henneberryl

2003-01-01

Size and weight measurements were made for all the life stages of Bemisia tabaci (Gennadius) B biotype from field grown cotton ( Gossypium hirsutum L. ) and cantaloupe ( Cucumis melo L., var. cantalupensis )in Phoenix, AZ and Fargo, ND, USA in 2000 and 2001. Nymphal volumes were derived from the measurements.The average nymphal volume increase for settled 1 st to the late 4th instar was exponential. The greatest increase in body volume occurred during development from the 3rd to early 4th instar. Nymphs on cotton leaves were wider,but not longer compared with those on cantaloupe. Ventral and dorsal depth ratios of nymphal bodies from 1st tolate 4th instars from cantaloupe leaves were significantly greater compared with those from cotton leaves. During nymphal development from 1st to 4th instar, the average (from the two host species) ventral body half volume in-creased by nearly 51 times compared with an increase of 28 times for the dorsal body half volume. Adult female and male average lengths, from heads to wing tips, were 1 126 μm and 953 μm, respectively. Average adult fe-male and male weights were 39 and 17 μg, respectively. Average widths, lengths, and weights of eggs from cottonand cantaloupe were, 99 μm, 197 μm, and 0.8 μg, respectively. Average widths, lengths, and weights for exu-viae of non-parasitized nymphs from both cotton and cantaloupe were 492 μm, 673 μm, and 1.20 μg, respective-ly; and widths, lengths, and weights of parasitized nymph exuviae were 452 μm, 665 μm, and 3.62 μg, respec-tively. Both exuviae from non-parasitized and parasitized nymphs from cotton leaves were wider, longer, and heavier than those from cantaloupe leaves.

Non-invasive assessment of distribution volume ratios and binding potential: tissue heterogeneity and interindividually averaged time-activity curves

Energy Technology Data Exchange (ETDEWEB)

Reimold, M.; Mueller-Schauenburg, W.; Dohmen, B.M.; Bares, R. [Department of Nuclear Medicine, University of Tuebingen, Otfried-Mueller-Strasse 14, 72076, Tuebingen (Germany); Becker, G.A. [Nuclear Medicine, University of Leipzig, Leipzig (Germany); Reischl, G. [Radiopharmacy, University of Tuebingen, Tuebingen (Germany)

2004-04-01

Due to the stochastic nature of radioactive decay, any measurement of radioactivity concentration requires spatial averaging. In pharmacokinetic analysis of time-activity curves (TAC), such averaging over heterogeneous tissues may introduce a systematic error (heterogeneity error) but may also improve the accuracy and precision of parameter estimation. In addition to spatial averaging (inevitable due to limited scanner resolution and intended in ROI analysis), interindividual averaging may theoretically be beneficial, too. The aim of this study was to investigate the effect of such averaging on the binding potential (BP) calculated with Logan's non-invasive graphical analysis and the ''simplified reference tissue method'' (SRTM) proposed by Lammertsma and Hume, on the basis of simulated and measured positron emission tomography data [{sup 11}C]d-threo-methylphenidate (dMP) and [{sup 11}C]raclopride (RAC) PET. dMP was not quantified with SRTM since the low k {sub 2} (washout rate constant from the first tissue compartment) introduced a high noise sensitivity. Even for considerably different shapes of TAC (dMP PET in parkinsonian patients and healthy controls, [{sup 11}C]raclopride in patients with and without haloperidol medication) and a high variance in the rate constants (e.g. simulated standard deviation of K {sub 1}=25%), the BP obtained from average TAC was close to the mean BP (<5%). However, unfavourably distributed parameters, especially a correlated large variance in two or more parameters, may lead to larger errors. In Monte Carlo simulations, interindividual averaging before quantification reduced the variance from the SRTM (beyond a critical signal to noise ratio) and the bias in Logan's method. Interindividual averaging may further increase accuracy when there is an error term in the reference tissue assumption E=DV {sub 2}-DV ' (DV {sub 2} = distribution volume of the first tissue compartment, DV &apos

Plasma and blood volume in the calf from birth till 90 days of age

International Nuclear Information System (INIS)

Moellerberg, L.; Ekman, L.; Jacobsson, S.-O.

1975-01-01

Determinations of plasma volume were made of 9 clinically healthy Swedish Red and White calves from birth to 90 days of age by means of the isotop dilution technique. Commercially available 131 I labelled human serum albumin was used. Calculation of the total blood volume was based on the plasma volume and packed cell volume. The plasma and blood volumes increased per kg body weight in average 17 and 14 percent respectively from directly after birth to 24 hrs. old. From 1 to 90 days of age the plasma and blood volume fell steadily per kg body weight. Plasma volume expressed as a percentage of body weight was 5.3 percent at birth, 6.5 percent at 1 day old, and 4.9 percent at 90 days old. Corresponding values for blood were 8.4, 9.3 and 7.0 percent. (author)

Preoperative computed tomography volumetry and graft weight estimation in adult living donor liver transplantation

Energy Technology Data Exchange (ETDEWEB)

Pinheiro, Rafael S.; Cruz Junior, Ruy J.; Andraus, Wellington; Ducatti, Liliana; Martino, Rodrigo B.; Nacif, Lucas S.; Rocha-Santos, Vinicius; Arantes, Rubens M.; D' Albuquerque, Luiz A.C., E-mail: rsnpinheiro@gmail.com [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Gastroenterologia. Div. de Transplante de Orgaos do Aparelho Digestivo; Lai, Quirino [Universidade de L' Aquila, San Salvatore Hospital (Italy); Ibuki, Felicia S.; Rocha, Manoel S. [Universidade de Sao Paulo (USP), SP (Brazil). Departamento de Radiologia

2017-09-01

Background: Computed tomography volumetry (CTV) is a useful tool for predicting graft weights (GW) for living donor liver transplantation (LDLT). Few studies have examined the correlation between CTV and GW in normal liver parenchyma. Aim: To analyze the correlation between CTV and GW in an adult LDLT population and provide a systematic review of the existing mathematical models to calculate partial liver graft weight. Methods: Between January 2009 and January 2013, 28 consecutive donors undergoing right hepatectomy for LDLT were retrospectively reviewed. All grafts were perfused with HTK solution. Estimated graft volume was estimated by CTV and these values were compared to the actual graft weight, which was measured after liver harvesting and perfusion. Results: Median actual GW was 782.5 g, averaged 791.43±136 g and ranged from 520-1185 g. Median estimated graft volume was 927.5 ml, averaged 944.86±200.74 ml and ranged from 600-1477 ml. Linear regression of estimated graft volume and actual GW was significantly linear (GW=0.82 estimated graft volume, r{sup 2} =0.98, slope=0.47, standard deviation of 0.024 and p<0.0001). Spearman Linear correlation was 0.65 with 95% CI of 0.45 – 0.99 (p<0.0001). Conclusion: The one-to-one rule did not applied in patients with normal liver parenchyma. A better estimation of graft weight could be reached by multiplying estimated graft volume by 0.82. (author)

Preoperative computed tomography volumetry and graft weight estimation in adult living donor liver transplantation

International Nuclear Information System (INIS)

Pinheiro, Rafael S.; Cruz Junior, Ruy J.; Andraus, Wellington; Ducatti, Liliana; Martino, Rodrigo B.; Nacif, Lucas S.; Rocha-Santos, Vinicius; Arantes, Rubens M.; D'Albuquerque, Luiz A.C.; Ibuki, Felicia S.; Rocha, Manoel S.

2017-01-01

Background: Computed tomography volumetry (CTV) is a useful tool for predicting graft weights (GW) for living donor liver transplantation (LDLT). Few studies have examined the correlation between CTV and GW in normal liver parenchyma. Aim: To analyze the correlation between CTV and GW in an adult LDLT population and provide a systematic review of the existing mathematical models to calculate partial liver graft weight. Methods: Between January 2009 and January 2013, 28 consecutive donors undergoing right hepatectomy for LDLT were retrospectively reviewed. All grafts were perfused with HTK solution. Estimated graft volume was estimated by CTV and these values were compared to the actual graft weight, which was measured after liver harvesting and perfusion. Results: Median actual GW was 782.5 g, averaged 791.43±136 g and ranged from 520-1185 g. Median estimated graft volume was 927.5 ml, averaged 944.86±200.74 ml and ranged from 600-1477 ml. Linear regression of estimated graft volume and actual GW was significantly linear (GW=0.82 estimated graft volume, r"2 =0.98, slope=0.47, standard deviation of 0.024 and p<0.0001). Spearman Linear correlation was 0.65 with 95% CI of 0.45 – 0.99 (p<0.0001). Conclusion: The one-to-one rule did not applied in patients with normal liver parenchyma. A better estimation of graft weight could be reached by multiplying estimated graft volume by 0.82. (author)

PREOPERATIVE COMPUTED TOMOGRAPHY VOLUMETRY AND GRAFT WEIGHT ESTIMATION IN ADULT LIVING DONOR LIVER TRANSPLANTATION

Science.gov (United States)

PINHEIRO, Rafael S.; CRUZ-JR, Ruy J.; ANDRAUS, Wellington; DUCATTI, Liliana; MARTINO, Rodrigo B.; NACIF, Lucas S.; ROCHA-SANTOS, Vinicius; ARANTES, Rubens M; LAI, Quirino; IBUKI, Felicia S.; ROCHA, Manoel S.; D´ALBUQUERQUE, Luiz A. C.

2017-01-01

ABSTRACT Background: Computed tomography volumetry (CTV) is a useful tool for predicting graft weights (GW) for living donor liver transplantation (LDLT). Few studies have examined the correlation between CTV and GW in normal liver parenchyma. Aim: To analyze the correlation between CTV and GW in an adult LDLT population and provide a systematic review of the existing mathematical models to calculate partial liver graft weight. Methods: Between January 2009 and January 2013, 28 consecutive donors undergoing right hepatectomy for LDLT were retrospectively reviewed. All grafts were perfused with HTK solution. Estimated graft volume was estimated by CTV and these values were compared to the actual graft weight, which was measured after liver harvesting and perfusion. Results: Median actual GW was 782.5 g, averaged 791.43±136 g and ranged from 520-1185 g. Median estimated graft volume was 927.5 ml, averaged 944.86±200.74 ml and ranged from 600-1477 ml. Linear regression of estimated graft volume and actual GW was significantly linear (GW=0.82 estimated graft volume, r2=0.98, slope=0.47, standard deviation of 0.024 and p<0.0001). Spearman Linear correlation was 0.65 with 95% CI of 0.45 - 0.99 (p<0.0001). Conclusion: The one-to-one rule did not applied in patients with normal liver parenchyma. A better estimation of graft weight could be reached by multiplying estimated graft volume by 0.82. PMID:28489167

Effects of Gestational Age and Birth Weight on Brain Volumes in Healthy 9 Year-Old Children

NARCIS (Netherlands)

van Soelen, I.L.C.; Brouwer, R.M.; Peper, J.S.; van Beijsterveldt, C.E.M.; van Leeuwen, M.; de Vries, L.S.; Kahn, R.S.; Hulshoff Pol, H.E.; Boomsma, D.I.

2010-01-01

Objective: To assess the effects of gestational age and birth weight on brain volumes in a population-based sample of normal developing children at the age of 9 years. Study design: A total of 192 children from twin births were included in the analyses. Data on gestational age and birth weight were

Weight, Volume, and Physical Properties of Major Hardwood Species in the Piedmont

Science.gov (United States)

Alexander Clark; Douglas R. Phillips; Douglas J. Frederick

1986-01-01

Weight, volume, and physical properties of trees 1 to 20 inches d.b.h.were determined for red maple, sweetgum, sycamore, yellow-poplar, elm, hickory, chestnut oak, scarlet oak, southern red oak, and white oak in the Piedmont of the Southeastern United States. A total of 772 trees were destructively sampled at 16 locations from Viryinia to Alabama. Hard hardwoods, soft...

Legacy tree data: A national database of detailed tree measurements for volume, weight, and physical properties

Science.gov (United States)

P.J. Radtke; D.M. Walker; A.R. Weiskittel; J. Frank; J.W. Coulston; J.A. Westfall

2015-01-01

Forest mensurationists in the United States have expended considerable effort over the past century making detailed observations of trees’ dimensions. In recent decades efforts have focused increasingly on weights and physical properties. Work is underway to compile original measurements from past volume, taper, and weight or biomass studies for North American tree...

Failure of Noninvasive Ventilation for De Novo Acute Hypoxemic Respiratory Failure: Role of Tidal Volume.

Science.gov (United States)

Carteaux, Guillaume; Millán-Guilarte, Teresa; De Prost, Nicolas; Razazi, Keyvan; Abid, Shariq; Thille, Arnaud W; Schortgen, Frédérique; Brochard, Laurent; Brun-Buisson, Christian; Mekontso Dessap, Armand

2016-02-01

A low or moderate expired tidal volume can be difficult to achieve during noninvasive ventilation for de novo acute hypoxemic respiratory failure (i.e., not due to exacerbation of chronic lung disease or cardiac failure). We assessed expired tidal volume and its association with noninvasive ventilation outcome. Prospective observational study. Twenty-four bed university medical ICU. Consecutive patients receiving noninvasive ventilation for acute hypoxemic respiratory failure between August 2010 and February 2013. Noninvasive ventilation was uniformly delivered using a simple algorithm targeting the expired tidal volume between 6 and 8 mL/kg of predicted body weight. Expired tidal volume was averaged and respiratory and hemodynamic variables were systematically recorded at each noninvasive ventilation session. Sixty-two patients were enrolled, including 47 meeting criteria for acute respiratory distress syndrome, and 32 failed noninvasive ventilation (51%). Pneumonia (n = 51, 82%) was the main etiology of acute hypoxemic respiratory failure. The median (interquartile range) expired tidal volume averaged over all noninvasive ventilation sessions (mean expired tidal volume) was 9.8 mL/kg predicted body weight (8.1-11.1 mL/kg predicted body weight). The mean expired tidal volume was significantly higher in patients who failed noninvasive ventilation as compared with those who succeeded (10.6 mL/kg predicted body weight [9.6-12.0] vs 8.5 mL/kg predicted body weight [7.6-10.2]; p = 0.001), and expired tidal volume was independently associated with noninvasive ventilation failure in multivariate analysis. This effect was mainly driven by patients with PaO2/FIO2 up to 200 mm Hg. In these patients, the expired tidal volume above 9.5 mL/kg predicted body weight predicted noninvasive ventilation failure with a sensitivity of 82% and a specificity of 87%. A low expired tidal volume is almost impossible to achieve in the majority of patients receiving noninvasive ventilation

Nutrient Composition and Weight Evaluation of some Newly ...

African Journals Online (AJOL)

The average weight ranged between 28.2 in improved white dent to 29.8 in improved yellow dent. The yellow dent variety will be particularly useful in improving level of micronutrient intake. The Journal of Food Technology in Africa Volume 7 No.1, 2002, pp. 27-29. KEY WORDS: Nutrient composition, white dent, yellow dent ...

Quantity Distortion Effect in Consumers' Perception of Different Volumes and Weights of Money: A Pilot Study.

Science.gov (United States)

Guido, Gianluigi; Piper, Luigi; Prete, M Irene; Mileti, Antonio; Fonda, Marco

2016-08-01

Consumers tend to misunderstand the physical value of cash money by adopting improper anchors for their judgments (e.g., banknote size and shape, currency denominations, etc.). In a pilot study carried out on a sample of 242 participants (n = 116 men; M age = 29.6 year, SD = 10.8), a quantity distortion effect was demonstrated by evaluating consumers' misperceptions of different monetary quantities, either in terms of volume or weight, using banknotes of the same denomination (€50). A threshold value was found, for both volume (€876,324) and weight (€371,779), above (below) which consumers tend to overrate (underrate) monetary amounts. The theoretical and operative implications are discussed. © The Author(s) 2016.

Repeatability of Brain Volume Measurements Made with the Atlas-based Method from T1-weighted Images Acquired Using a 0.4 Tesla Low Field MR Scanner.

Science.gov (United States)

Goto, Masami; Suzuki, Makoto; Mizukami, Shinya; Abe, Osamu; Aoki, Shigeki; Miyati, Tosiaki; Fukuda, Michinari; Gomi, Tsutomu; Takeda, Tohoru

2016-10-11

An understanding of the repeatability of measured results is important for both the atlas-based and voxel-based morphometry (VBM) methods of magnetic resonance (MR) brain volumetry. However, many recent studies that have investigated the repeatability of brain volume measurements have been performed using static magnetic fields of 1-4 tesla, and no study has used a low-strength static magnetic field. The aim of this study was to investigate the repeatability of measured volumes using the atlas-based method and a low-strength static magnetic field (0.4 tesla). Ten healthy volunteers participated in this study. Using a 0.4 tesla magnetic resonance imaging (MRI) scanner and a quadrature head coil, three-dimensional T 1 -weighted images (3D-T 1 WIs) were obtained from each subject, twice on the same day. VBM8 software was used to construct segmented normalized images [gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) images]. The regions-of-interest (ROIs) of GM, WM, CSF, hippocampus (HC), orbital gyrus (OG), and cerebellum posterior lobe (CPL) were generated using WFU PickAtlas. The percentage change was defined as[100 × (measured volume with first segmented image - mean volume in each subject)/(mean volume in each subject)]The average percentage change was calculated as the percentage change in the 6 ROIs of the 10 subjects. The mean of the average percentage changes for each ROI was as follows: GM, 0.556%; WM, 0.324%; CSF, 0.573%; HC, 0.645%; OG, 1.74%; and CPL, 0.471%. The average percentage change was higher for the orbital gyrus than for the other ROIs. We consider that repeatability of the atlas-based method is similar between 0.4 and 1.5 tesla MR scanners. To our knowledge, this is the first report to show that the level of repeatability with a 0.4 tesla MR scanner is adequate for the estimation of brain volume change by the atlas-based method.

SACALCCYL, Calculates the average solid angle subtended by a volume; SACALC2B, Calculates the average solid angle for source-detector geometries

International Nuclear Information System (INIS)

Whitcher, Ralph

2007-01-01

1 - Description of program or function: SACALC2B calculates the average solid angle subtended by a rectangular or circular detector window to a coaxial or non-coaxial rectangular, circular or point source, including where the source and detector planes are not parallel. SACALC C YL calculates the average solid angle subtended by a cylinder to a rectangular or circular source, plane or thick, at any location and orientation. This is needed, for example, in calculating the intrinsic gamma efficiency of a detector such as a GM tube. The program also calculates the number of hits on the cylinder side and on each end, and the average path length through the detector volume (assuming no scattering or absorption). Point sources can be modelled by using a circular source of zero radius. NEA-1688/03: Documentation has been updated (January 2006). 2 - Methods: The program uses a Monte Carlo method to calculate average solid angle for source-detector geometries that are difficult to analyse by analytical methods. The values of solid angle are calculated to accuracies of typically better than 0.1%. The calculated values from the Monte Carlo method agree closely with those produced by polygon approximation and numerical integration by Gardner and Verghese, and others. 3 - Restrictions on the complexity of the problem: The program models a circular or rectangular detector in planes that are not necessarily coaxial, nor parallel. Point sources can be modelled by using a circular source of zero radius. The sources are assumed to be uniformly distributed. NEA-1688/04: In SACALC C YL, to avoid rounding errors, differences less than 1 E-12 are assumed to be zero

Measurement of average density and relative volumes in a dispersed two-phase fluid

Science.gov (United States)

Sreepada, Sastry R.; Rippel, Robert R.

1992-01-01

An apparatus and a method are disclosed for measuring the average density and relative volumes in an essentially transparent, dispersed two-phase fluid. A laser beam with a diameter no greater than 1% of the diameter of the bubbles, droplets, or particles of the dispersed phase is directed onto a diffraction grating. A single-order component of the diffracted beam is directed through the two-phase fluid and its refraction is measured. Preferably, the refracted beam exiting the fluid is incident upon a optical filter with linearly varing optical density and the intensity of the filtered beam is measured. The invention can be combined with other laser-based measurement systems, e.g., laser doppler anemometry.

Weight, Volume, and Physical Properties of Major Hardwood Species in the Upland-South

Science.gov (United States)

Alexander Clark; Douglas R. Phillips; Douglas J. Frederick

1986-01-01

The weight, volume, and physical properties oftrees1 to 20 inchesd.b.h.were determined for sweetgum, yellow-poplar, hickory, post oak, scarlet oak, southern red oak, and white oakin northern Alabama and Mississippi, eastern Arkansas, southern Kentucky and Tennessee. Hard hardwoods, soft hardwoods, and individual species equations are presented for predicting green and...

Predicting objective function weights from patient anatomy in prostate IMRT treatment planning

International Nuclear Information System (INIS)

Lee, Taewoo; Hammad, Muhannad; Chan, Timothy C. Y.; Craig, Tim; Sharpe, Michael B.

2013-01-01

Purpose: Intensity-modulated radiation therapy (IMRT) treatment planning typically combines multiple criteria into a single objective function by taking a weighted sum. The authors propose a statistical model that predicts objective function weights from patient anatomy for prostate IMRT treatment planning. This study provides a proof of concept for geometry-driven weight determination. Methods: A previously developed inverse optimization method (IOM) was used to generate optimal objective function weights for 24 patients using their historical treatment plans (i.e., dose distributions). These IOM weights were around 1% for each of the femoral heads, while bladder and rectum weights varied greatly between patients. A regression model was developed to predict a patient's rectum weight using the ratio of the overlap volume of the rectum and bladder with the planning target volume at a 1 cm expansion as the independent variable. The femoral head weights were fixed to 1% each and the bladder weight was calculated as one minus the rectum and femoral head weights. The model was validated using leave-one-out cross validation. Objective values and dose distributions generated through inverse planning using the predicted weights were compared to those generated using the original IOM weights, as well as an average of the IOM weights across all patients. Results: The IOM weight vectors were on average six times closer to the predicted weight vectors than to the average weight vector, usingl 2 distance. Likewise, the bladder and rectum objective values achieved by the predicted weights were more similar to the objective values achieved by the IOM weights. The difference in objective value performance between the predicted and average weights was statistically significant according to a one-sided sign test. For all patients, the difference in rectum V54.3 Gy, rectum V70.0 Gy, bladder V54.3 Gy, and bladder V70.0 Gy values between the dose distributions generated by the

Extending a Consensus-based Fuzzy Ordered Weighting Average (FOWA Model in New Water Quality Indices

Directory of Open Access Journals (Sweden)

Mohammad Ali Baghapour

2017-07-01

Full Text Available In developing a specific WQI (Water Quality Index, many water quality parameters are involved with different levels of importance. The impact of experts’ different opinions and viewpoints, current risks affecting their opinions, and plurality of the involved parameters double the significance of the issue. Hence, the current study tries to apply a consensus-based FOWA (Fuzzy Ordered Weighting Average model as one of the most powerful and well-known Multi Criteria Decision Making (MCDM techniques to determine the importance of the used parameters in the development of such WQIs which is shown with an example. This operator has provided the capability of modeling the risks in decision-making through applying the optimistic degree of stakeholders and their power coupled with the use of fuzzy numbers. Totally, 22 water quality parameters for drinking purposes are considered in this study. To determine the weight of each parameter, the viewpoints of 4 decision-making groups of experts are taken into account. After determining the final weights, to validate the use of each parameter in a potential WQI, consensus degrees of both the decision makers and the parameters are calculated. All calculations are carried out by using the expertise software called Group Fuzzy Decision Making (GFDM. The highest and the lowest weight values, 0.999 and 0.073 respectively, are related to Hg and temperature. Regarding the type of consumption that is drinking, the parameters’ weights and ranks are consistent with their health impacts. Moreover, the decision makers’ highest and lowest consensus degrees were 0.9905 and 0.9669, respectively. Among the water quality parameters, temperature (with consensus degree of 0.9972 and Pb (with consensus degree of 0.9665, received the highest and lowest agreement from the decision making group. This study indicates that the weight of parameters in determining water quality largely depends on the experts’ opinions and

Extending a Consensus-based Fuzzy Ordered Weighting Average (FOWA Model in New Water Quality Indices

Directory of Open Access Journals (Sweden)

Mohammad Ali Baghapour

2017-07-01

Full Text Available In developing a specific WQI (Water Quality Index, many quality parameters are involved with different levels of importance. The impact of experts’ different opinions and viewpoints, current risks affecting their opinions, and plurality of the involved parameters double the significance of the issue. Hence, the current study tries to apply a consensus-based FOWA (Fuzzy Ordered Weighting Average model as one of the most powerful and well-known Multi-Criteria Decision- Making (MCDM techniques to determine the importance of the used parameters in the development of such WQIs which is shown with an example. This operator has provided the capability of modeling the risks in decision-making through applying the optimistic degree of stakeholders and their power coupled with the use of fuzzy numbers. Totally, 22 water quality parameters for drinking purposes were considered in this study. To determine the weight of each parameter, the viewpoints of 4 decision-making groups of experts were taken into account. After determining the final weights, to validate the use of each parameter in a potential WQI, consensus degrees of both the decision makers and the parameters are calculated. The highest and the lowest weight values, 0.999 and 0.073 respectively, were related to Hg and temperature. Regarding the type of consumption that was drinking, the parameters’ weights and ranks were consistent with their health impacts. Moreover, the decision makers’ highest and lowest consensus degrees were 0.9905 and 0.9669, respectively. Among the water quality parameters, temperature (with consensus degree of 0.9972 and Pb (with consensus degree of 0.9665, received the highest and lowest agreement with the decision-making group. This study indicated that the weight of parameters in determining water quality largely depends on the experts’ opinions and approaches. Moreover, using the FOWA model provides results accurate and closer- to-reality on the significance of

Induced Unbalanced Linguistic Ordered Weighted Average and Its Application in Multiperson Decision Making

Directory of Open Access Journals (Sweden)

Lucas Marin

2014-01-01

Full Text Available Linguistic variables are very useful to evaluate alternatives in decision making problems because they provide a vocabulary in natural language rather than numbers. Some aggregation operators for linguistic variables force the use of a symmetric and uniformly distributed set of terms. The need to relax these conditions has recently been posited. This paper presents the induced unbalanced linguistic ordered weighted average (IULOWA operator. This operator can deal with a set of unbalanced linguistic terms that are represented using fuzzy sets. We propose a new order-inducing criterion based on the specificity and fuzziness of the linguistic terms. Different relevancies are given to the fuzzy values according to their uncertainty degree. To illustrate the behaviour of the precision-based IULOWA operator, we present an environmental assessment case study in which a multiperson multicriteria decision making model is applied.

Comparison of MRI pulse sequences in defining prostate volume after permanent implantation

International Nuclear Information System (INIS)

McLaughlin, P.W.; Narayana, V.; Drake, D.G.; Miller, B.M.; Marsh, L.; Chan, J.; Gonda, R.; Winfield, R.J.; Roberson, P.L.

2002-01-01

Purpose: To determine the relative value of three MRI pulse sequences in defining the prostate volume after permanent implantation. Methods and Materials: A total of 45 patients who received a permanent 125 I implant were studied. Two weeks after implantation, an axial CT scan (2 mm thickness) and T 1 -weighted, T 1 -weighted fat saturation, and T 2 -weighted axial MRI (3-mm) studies were obtained. The prostate volumes were compared with the initial ultrasound planning volumes, and subsequently the CT, T 1 -weighted, and T 1 -weighted fat saturation MRI volumes were compared with the T 2 -weighted volumes. Discrepancies in volume were evaluated by visual inspection of the registered axial images and the registration of axial volumes on the sagittal T 2 -weighted volumes. In a limited set of patients, pre- and postimplant CT and T 2 -weighted MRI studies were available for comparison to determine whether prostate volume changes after implant were dependent on the imaging modality. Results: T 1 -weighted and T 1 -weighted fat saturation MRI and CT prostate volumes were consistently larger than the T 2 -weighted MRI prostate volumes, with a volume on average 1.33 (SD 0.24) times the T 2 -weighted volume. This discrepancy was due to the superiority of T 2 -weighted MRI for prostate definition at the following critical interfaces: membranous urethra, apex, and anterior base-bladder and posterior base-seminal vesicle interfaces. The differences in prostate definition in the anterior base region suggest that the commonly reported underdose may be due to overestimation of the prostate in this region by CT. The consistent difference in volumes suggests that the degree of swelling observed after implantation is in part a function of the imaging modality. In patients with pre- and postimplant CT and T 2 -weighted MRI images, swelling on the T 2 -weighted images was 1.1 times baseline and on CT was 1.3 times baseline, confirming the imaging modality dependence of prostate

High frequency oscillatory ventilation with lung volume optimization in very low birth weight newborns – a nine-year experience

Directory of Open Access Journals (Sweden)

José Nona

2009-09-01

Full Text Available Objective: To evaluate the clinical outcome of very low birth weight newborns, submitted to high frequency oscillatory ventilation with a strategy of early lung volume optimization. Methods: Descriptive prospective study in a nine-year period, between 1999 January 1st to 2008 January 1st. All the very low birth weight newborns were born in Dr. Alfredo da Costa Maternity, Lisbon, Portugal, were admitted to the Neonatal Intensive Care Unit and submitted to high frequency oscillatory ventilation with early lung volume optimization; these newborns were followed-up since birth and their charts were analyzed periodically until hospital discharge. Rresults: From a total population of 730 very low birth weight inborns, 117 babies died (16% and 613 survived (84%. The median of birth weight was 975 g and the gestational age median was 28 weeks. For the survivors, the median ventilation and oxygenation times were 3 and 18 days, respectively. The incidence of chronic lung disease was 9.5%, with nine newborns discharged on oxygen therapy. The incidence of intraventricular hemorrhage III – IV (total population group was 11.5% and the incidence of retinopathy of prematurity grade 3 or higher was 8.0%. Cconclusions: High frequency oscillatory ventilation with early lung volume optimization strategy reduced the need of respiratory support, and improved pulmonary and global outcomes in very low birth weight infants with respiratory distress syndrome.

Distribution of volumes of individual glomeruli in kidneys at autopsy: association with age, nephron number, birth weight and body mass index.

Science.gov (United States)

Hoy, W E; Hughson, M D; Zimanyi, M; Samuel, T; Douglas-Denton, R; Holden, L; Mott, S; Bertram, J F

2010-11-01

Glomerular hypertrophy occurs in a number of normal and pathological states. Glomerular volume in kidneys at autopsy is usually indirectly derived from estimates of total glomerular mass and nephron number, and provides only a single value per kidney, with no indication of the range of volumes of glomeruli within the kidney of any given subject. We review findings of the distribution of volumes of different glomeruli within subjects without kidney disease, and their correlations with age, nephron number, birth weight and body mass index (BMI). The study describes findings from autopsy kidneys of selected adult white males from the Southeast USA who had unexpected deaths, and who did not have renal scarring or renal disease. Total glomerular (nephron) number and total glomerular volume were estimated using the disector/fractionator combination, and mean glomerular volume (Vglom) was derived. The volumes of 30 individual glomeruli (IGV) in each subject were determined using the disector/Cavalieri method. IGV values were compared by categories of age, nephron number, birth weight and BMI. There was substantial variation in IGV within subjects. Older age, lower nephron number, lower birth weight and gross obesity were associated with higher mean IGV and with greater IGV heterogeneity. High Vglom and high IGVs were associated with more glomerulosclerosis. However, amongst the generally modest numbers of sclerosed glomeruli, the pattern was uniformly of ischemic collapse of the glomerular tuft. There was no detectable focal segmental glomerular tuft injury. In this series of people without overt renal disease, greater age, nephron deficit, lower birth weight and obesity were marked by glomerular enlargement and greater glomerular volume heterogeneity within individuals.

The effect of holiday weight gain on body weight.

Science.gov (United States)

Schoeller, Dale A

2014-07-01

The topic of holiday weight gain has been a frequent subject of the lay media; however, scientific interest has only been recent. Multiple studies in Western societies have reported average weight gains among adults during the period between mid-November and mid-January that were about 0.5 kg. The range in individual weight changes was large, however, and the already overweight and obese gain more weight than those who are healthy weight. When the average gain across the year was also measured, the holiday weight was the major contributor to annual excess weight gain. Efforts patterned to increase awareness to energy balance and body weight have been shown to be successful at reducing such gain. An exception to holiday weight gain being a major contributor to annual excess gain has been children, in whom summer weight gains have been observed to be the major contributor to average excess weight gain. Copyright © 2014 Elsevier Inc. All rights reserved.

Ischemic lesion volume determination on diffusion weighted images vs. apparent diffusion coefficient maps.

Science.gov (United States)

Bråtane, Bernt Tore; Bastan, Birgul; Fisher, Marc; Bouley, James; Henninger, Nils

2009-07-07

Though diffusion weighted imaging (DWI) is frequently used for identifying the ischemic lesion in focal cerebral ischemia, the understanding of spatiotemporal evolution patterns observed with different analysis methods remains imprecise. DWI and calculated apparent diffusion coefficient (ADC) maps were serially obtained in rat stroke models (MCAO): permanent, 90 min, and 180 min temporary MCAO. Lesion volumes were analyzed in a blinded and randomized manner by 2 investigators using (i) a previously validated ADC threshold, (ii) visual determination of hypointense regions on ADC maps, and (iii) visual determination of hyperintense regions on DWI. Lesion volumes were correlated with 24 hour 2,3,5-triphenyltetrazoliumchloride (TTC)-derived infarct volumes. TTC-derived infarct volumes were not significantly different from the ADC and DWI-derived lesion volumes at the last imaging time points except for significantly smaller DWI lesions in the pMCAO model (p=0.02). Volumetric calculation based on TTC-derived infarct also correlated significantly stronger to volumetric calculation based on last imaging time point derived lesions on ADC maps than DWI (pdetermined lesion volumes on ADC maps and DWI by both investigators correlated significantly with threshold-derived lesion volumes on ADC maps with the former method demonstrating a stronger correlation. There was also a better interrater agreement for ADC map analysis than for DWI analysis. Ischemic lesion determination by ADC was more accurate in final infarct prediction, rater independent, and provided exclusive information on ischemic lesion reversibility.

Angular finite volume method for solving the multigroup transport equation with piecewise average scattering cross sections

International Nuclear Information System (INIS)

Calloo, A.; Vidal, J.F.; Le Tellier, R.; Rimpault, G.

2011-01-01

This paper deals with the solving of the multigroup integro-differential form of the transport equation for fine energy group structure. In that case, multigroup transfer cross sections display strongly peaked shape for light scatterers and the current Legendre polynomial expansion is not well-suited to represent them. Furthermore, even if considering an exact scattering cross sections representation, the scattering source in the discrete ordinates method (also known as the Sn method) being calculated by sampling the angular flux at given directions, may be wrongly computed due to lack of angular support for the angular flux. Hence, following the work of Gerts and Matthews, an angular finite volume solver has been developed for 2D Cartesian geometries. It integrates the multigroup transport equation over discrete volume elements obtained by meshing the unit sphere with a product grid over the polar and azimuthal coordinates and by considering the integrated flux per solid angle element. The convergence of this method has been compared to the S_n method for a highly anisotropic benchmark. Besides, piecewise-average scattering cross sections have been produced for non-bound Hydrogen atoms using a free gas model for thermal neutrons. LWR lattice calculations comparing Legendre representations of the Hydrogen scattering multigroup cross section at various orders and piecewise-average cross sections for this same atom are carried out (while keeping a Legendre representation for all other isotopes). (author)

Memory function and hippocampal volumes in preterm born very-low-birth-weight (VLBW) young adults.

Science.gov (United States)

Aanes, Synne; Bjuland, Knut Jørgen; Skranes, Jon; Løhaugen, Gro C C

2015-01-15

The hippocampi are regarded as core structures for learning and memory functions, which is important for daily functioning and educational achievements. Previous studies have linked reduction in hippocampal volume to working memory problems in very low birth weight (VLBW; ≤ 1500 g) children and reduced general cognitive ability in VLBW adolescents. However, the relationship between memory function and hippocampal volume has not been described in VLBW subjects reaching adulthood. The aim of the study was to investigate memory function and hippocampal volume in VLBW young adults, both in relation to perinatal risk factors and compared to term born controls, and to look for structure-function relationships. Using Wechsler Memory Scale-III and MRI, we included 42 non-disabled VLBW and 61 control individuals at age 19-20 years, and related our findings to perinatal risk factors in the VLBW-group. The VLBW young adults achieved lower scores on several subtests of the Wechsler Memory Scale-III, resulting in lower results in the immediate memory indices (visual and auditory), the working memory index, and in the visual delayed and general memory delayed indices, but not in the auditory delayed and auditory recognition delayed indices. The VLBW group had smaller absolute and relative hippocampal volumes than the controls. In the VLBW group inferior memory function, especially for the working memory index, was related to smaller hippocampal volume, and both correlated with lower birth weight and more days in the neonatal intensive care unit (NICU). Our results may indicate a structural-functional relationship in the VLBW group due to aberrant hippocampal development and functioning after preterm birth. Copyright © 2014 Elsevier Inc. All rights reserved.

Diffusion-weighted MR imaging of the normal fetal lung

International Nuclear Information System (INIS)

Balassy, Csilla; Kasprian, Gregor; Weber, Michael; Hoermann, Marcus; Bankier, Alexander; Herold, Christian J.; Prayer, Daniela; Brugger, Peter C.; Csapo, Bence; Bammer, Roland

2008-01-01

To quantify apparent diffusion coefficient (ADC) changes in fetuses with normal lungs and to determine whether ADC can be used in the assessment of fetal lung development. In 53 pregnancies (20-37th weeks of gestation), we measured ADC on diffusion-weighted imaging (DWI) in the apical, middle, and basal thirds of the right lung. ADCs were correlated with gestational age. Differences between the ADCs were assessed. Fetal lung volumes were measured on T2-weighted sequences and correlated with ADCs and with age. ADCs were 2.13 ± 0.44 μm 2 /ms (mean ± SD) in the apex, 1.99 ± 0.42 μm 2 /ms (mean ± SD) in the middle third, and 1.91 ± 0.41 μm 2 /ms (mean ± SD) in the lung base. Neither the individual ADC values nor average ADC values showed a significant correlation with gestational age or with lung volumes. Average ADCs decreased significantly from the lung apex toward the base. Individual ADCs showed little absolute change and heterogeneity. Lung volumes increased significantly during gestation. We have not been able to identify a pattern of changes in the ADC values that correlate with lung maturation. Furthermore, the individual, gravity-related ADC changes are subject to substantial variability and show nonuniform behavior. ADC can therefore not be used as an indicator of lung maturity. (orig.)

Diffusion-weighted MR imaging of the normal fetal lung

Energy Technology Data Exchange (ETDEWEB)

Balassy, Csilla; Kasprian, Gregor; Weber, Michael; Hoermann, Marcus; Bankier, Alexander; Herold, Christian J.; Prayer, Daniela [Medical University of Vienna, Department of Radiology, Vienna (Austria); Brugger, Peter C. [Medical University of Vienna, Center of Anatomy and Cell Biology, Vienna (Austria); Csapo, Bence [Medical University of Vienna, Department of Obstetrics and Gyneocology, Vienna (Austria); Bammer, Roland [University of Stanford, Department of Radiology, Stanford, CA (United States)

2008-04-15

To quantify apparent diffusion coefficient (ADC) changes in fetuses with normal lungs and to determine whether ADC can be used in the assessment of fetal lung development. In 53 pregnancies (20-37th weeks of gestation), we measured ADC on diffusion-weighted imaging (DWI) in the apical, middle, and basal thirds of the right lung. ADCs were correlated with gestational age. Differences between the ADCs were assessed. Fetal lung volumes were measured on T2-weighted sequences and correlated with ADCs and with age. ADCs were 2.13 {+-} 0.44 {mu}m{sup 2}/ms (mean {+-} SD) in the apex, 1.99 {+-} 0.42 {mu}m{sup 2}/ms (mean {+-} SD) in the middle third, and 1.91 {+-} 0.41 {mu}m{sup 2}/ms (mean {+-} SD) in the lung base. Neither the individual ADC values nor average ADC values showed a significant correlation with gestational age or with lung volumes. Average ADCs decreased significantly from the lung apex toward the base. Individual ADCs showed little absolute change and heterogeneity. Lung volumes increased significantly during gestation. We have not been able to identify a pattern of changes in the ADC values that correlate with lung maturation. Furthermore, the individual, gravity-related ADC changes are subject to substantial variability and show nonuniform behavior. ADC can therefore not be used as an indicator of lung maturity. (orig.)

Characterization of Volume F Trash from Four Recent STS Missions: Weights, Categorization, Water Content

Science.gov (United States)

Strayer, Richard F.; Hummerick, Mary E.; Richards, Jeffrey T.; McCoy, LaShelle E.; Roberts, Michael S.; Wheeler, Raymond M.

2011-01-01

The fate of space-generated solid wastes, including trash, for future missions is under consideration by NASA. Several potential treatment options are under consideration and active technology development. Potential fates for space-generated solid wastes are: Storage without treatment; storage after treatment(s) including volume reduction, water recovery, sterilization, and recovery plus recycling of waste materials. Recycling might be important for partial or full closure scenarios because of the prohibitive costs associated with resupply of consumable materials. For this study, we determined the composition of trash returned from four recent STS missions. The trash material was 'Volume F' trash and other trash, in large zip-lock bags, that accompanied the Volume F trash. This is the first of two submitted papers on these wastes. This one will cover trash content, weight and water content. The other will report on the microbial Characterization of this trash. STS trash was usually made available within 2 days of landing at KSC. The Volume F bag was weighed, opened and the contents were catalogued and placed into one of the following categories: food waste (and containers), drink containers, personal hygiene items - including EVA maximum absorbent garments (MAGs)and Elbow packs (daily toilet wipes, etc), paper, and packaging materials - plastic firm and duct tape. Trash generation rates for the four STS missions: Total wet trash was 0.602 plus or minus 0.089 kg(sub wet) crew(sup -1) d(sup -1) containing about 25% water at 0.154 plus or minus 0.030 kg(sub water) crew(sup -1) d(sup -1) (avg plus or minus stdev). Cataloguing by category: personal hygiene wastes accounted for 50% of the total trash and 69% of the total water for the four missions; drink items were 16% of total weight and 16% water; food wastes were 22% of total weight and 15% of the water; office waste and plastic film were 2% and 11% of the total waste and did not contain any water. The results can be

Angular finite volume method for solving the multigroup transport equation with piecewise average scattering cross sections

Energy Technology Data Exchange (ETDEWEB)

Calloo, A.; Vidal, J.F.; Le Tellier, R.; Rimpault, G., E-mail: ansar.calloo@cea.fr, E-mail: jean-francois.vidal@cea.fr, E-mail: romain.le-tellier@cea.fr, E-mail: gerald.rimpault@cea.fr [CEA, DEN, DER/SPRC/LEPh, Saint-Paul-lez-Durance (France)

2011-07-01

This paper deals with the solving of the multigroup integro-differential form of the transport equation for fine energy group structure. In that case, multigroup transfer cross sections display strongly peaked shape for light scatterers and the current Legendre polynomial expansion is not well-suited to represent them. Furthermore, even if considering an exact scattering cross sections representation, the scattering source in the discrete ordinates method (also known as the Sn method) being calculated by sampling the angular flux at given directions, may be wrongly computed due to lack of angular support for the angular flux. Hence, following the work of Gerts and Matthews, an angular finite volume solver has been developed for 2D Cartesian geometries. It integrates the multigroup transport equation over discrete volume elements obtained by meshing the unit sphere with a product grid over the polar and azimuthal coordinates and by considering the integrated flux per solid angle element. The convergence of this method has been compared to the S{sub n} method for a highly anisotropic benchmark. Besides, piecewise-average scattering cross sections have been produced for non-bound Hydrogen atoms using a free gas model for thermal neutrons. LWR lattice calculations comparing Legendre representations of the Hydrogen scattering multigroup cross section at various orders and piecewise-average cross sections for this same atom are carried out (while keeping a Legendre representation for all other isotopes). (author)

Homogenization via formal multiscale asymptotics and volume averaging: How do the two techniques compare?

KAUST Repository

Davit, Yohan

2013-12-01

A wide variety of techniques have been developed to homogenize transport equations in multiscale and multiphase systems. This has yielded a rich and diverse field, but has also resulted in the emergence of isolated scientific communities and disconnected bodies of literature. Here, our goal is to bridge the gap between formal multiscale asymptotics and the volume averaging theory. We illustrate the methodologies via a simple example application describing a parabolic transport problem and, in so doing, compare their respective advantages/disadvantages from a practical point of view. This paper is also intended as a pedagogical guide and may be viewed as a tutorial for graduate students as we provide historical context, detail subtle points with great care, and reference many fundamental works. © 2013 Elsevier Ltd.

Pancreas segmentation from 3D abdominal CT images using patient-specific weighted subspatial probabilistic atlases

Science.gov (United States)

Karasawa, Kenichi; Oda, Masahiro; Hayashi, Yuichiro; Nimura, Yukitaka; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Rueckert, Daniel; Mori, Kensaku

2015-03-01

Abdominal organ segmentations from CT volumes are now widely used in the computer-aided diagnosis and surgery assistance systems. Among abdominal organs, the pancreas is especially difficult to segment because of its large individual differences of the shape and position. In this paper, we propose a new pancreas segmentation method from 3D abdominal CT volumes using patient-specific weighted-subspatial probabilistic atlases. First of all, we perform normalization of organ shapes in training volumes and an input volume. We extract the Volume Of Interest (VOI) of the pancreas from the training volumes and an input volume. We divide each training VOI and input VOI into some cubic regions. We use a nonrigid registration method to register these cubic regions of the training VOI to corresponding regions of the input VOI. Based on the registration results, we calculate similarities between each cubic region of the training VOI and corresponding region of the input VOI. We select cubic regions of training volumes having the top N similarities in each cubic region. We subspatially construct probabilistic atlases weighted by the similarities in each cubic region. After integrating these probabilistic atlases in cubic regions into one, we perform a rough-to-precise segmentation of the pancreas using the atlas. The results of the experiments showed that utilization of the training volumes having the top N similarities in each cubic region led good results of the pancreas segmentation. The Jaccard Index and the average surface distance of the result were 58.9% and 2.04mm on average, respectively.

Application of method of volume averaging coupled with time resolved PIV to determine transport characteristics of turbulent flows in porous bed

Science.gov (United States)

Patil, Vishal; Liburdy, James

2012-11-01

Turbulent porous media flows are encountered in catalytic bed reactors and heat exchangers. Dispersion and mixing properties of these flows play an essential role in efficiency and performance. In an effort to understand these flows, pore scale time resolved PIV measurements in a refractive index matched porous bed were made. Pore Reynolds numbers, based on hydraulic diameter and pore average velocity, were varied from 400-4000. Jet-like flows and recirculation regions associated with large scale structures were found to exist. Coherent vortical structures which convect at approximately 0.8 times the pore average velocity were identified. These different flow regions exhibited different turbulent characteristics and hence contributed unequally to global transport properties of the bed. The heterogeneity present within a pore and also from pore to pore can be accounted for in estimating transport properties using the method of volume averaging. Eddy viscosity maps and mean velocity field maps, both obtained from PIV measurements, along with the method of volume averaging were used to predict the dispersion tensor versus Reynolds number. Asymptotic values of dispersion compare well to existing correlations. The role of molecular diffusion was explored by varying the Schmidt number and molecular diffusion was found to play an important role in tracer transport, especially in recirculation regions. Funding by NSF grant 0933857, Particulate and Multiphase Processing.

Automation of registration of sample weights for high-volume neutron activation analysis at the IBR-2 reactor of FLNP, JINR

International Nuclear Information System (INIS)

Dmitriev, A.Yu.; Dmitriev, F.A.

2015-01-01

The 'Weight' software tool was created at FLNP JINR to automate the reading of analytical balance readouts and saving these values in the NAA database. The analytical balance connected to the personal computer is used to measure weight values. The 'Weight' software tool controls the reading of weight values and the exchange of information with the NAA database. The weighing process of a large amount of samples is reliably provided during high-volume neutron activation analysis. [ru

Effect of tank geometry on its average performance

Science.gov (United States)

Orlov, Aleksey A.; Tsimbalyuk, Alexandr F.; Malyugin, Roman V.; Leontieva, Daria A.; Kotelnikova, Alexandra A.

2018-03-01

The mathematical model of non-stationary filling of vertical submerged tanks with gaseous uranium hexafluoride is presented in the paper. There are calculations of the average productivity, heat exchange area, and filling time of various volumes tanks with smooth inner walls depending on their "height : radius" ratio as well as the average productivity, degree, and filling time of horizontal ribbing tank with volume 6.10-2 m3 with change central hole diameter of the ribs. It has been shown that the growth of "height / radius" ratio in tanks with smooth inner walls up to the limiting values allows significantly increasing tank average productivity and reducing its filling time. Growth of H/R ratio of tank with volume 1.0 m3 to the limiting values (in comparison with the standard tank having H/R equal 3.49) augments tank productivity by 23.5 % and the heat exchange area by 20%. Besides, we have demonstrated that maximum average productivity and a minimum filling time are reached for the tank with volume 6.10-2 m3 having central hole diameter of horizontal ribs 6.4.10-2 m.

Dictionary Based Segmentation in Volumes

DEFF Research Database (Denmark)

Emerson, Monica Jane; Jespersen, Kristine Munk; Jørgensen, Peter Stanley

2015-01-01

We present a method for supervised volumetric segmentation based on a dictionary of small cubes composed of pairs of intensity and label cubes. Intensity cubes are small image volumes where each voxel contains an image intensity. Label cubes are volumes with voxelwise probabilities for a given...... label. The segmentation process is done by matching a cube from the volume, of the same size as the dictionary intensity cubes, to the most similar intensity dictionary cube, and from the associated label cube we get voxel-wise label probabilities. Probabilities from overlapping cubes are averaged...... and hereby we obtain a robust label probability encoding. The dictionary is computed from labeled volumetric image data based on weighted clustering. We experimentally demonstrate our method using two data sets from material science – a phantom data set of a solid oxide fuel cell simulation for detecting...

Lagrangian averaging with geodesic mean.

Science.gov (United States)

Oliver, Marcel

2017-11-01

This paper revisits the derivation of the Lagrangian averaged Euler (LAE), or Euler- α equations in the light of an intrinsic definition of the averaged flow map as the geodesic mean on the volume-preserving diffeomorphism group. Under the additional assumption that first-order fluctuations are statistically isotropic and transported by the mean flow as a vector field, averaging of the kinetic energy Lagrangian of an ideal fluid yields the LAE Lagrangian. The derivation presented here assumes a Euclidean spatial domain without boundaries.

Averaging processes in granular flows driven by gravity

Science.gov (United States)

Rossi, Giulia; Armanini, Aronne

2016-04-01

One of the more promising theoretical frames to analyse the two-phase granular flows is offered by the similarity of their rheology with the kinetic theory of gases [1]. Granular flows can be considered a macroscopic equivalent of the molecular case: the collisions among molecules are compared to the collisions among grains at a macroscopic scale [2,3]. However there are important statistical differences in dealing with the two applications. In the two-phase fluid mechanics, there are two main types of average: the phasic average and the mass weighed average [4]. The kinetic theories assume that the size of atoms is so small, that the number of molecules in a control volume is infinite. With this assumption, the concentration (number of particles n) doesn't change during the averaging process and the two definitions of average coincide. This hypothesis is no more true in granular flows: contrary to gases, the dimension of a single particle becomes comparable to that of the control volume. For this reason, in a single realization the number of grain is constant and the two averages coincide; on the contrary, for more than one realization, n is no more constant and the two types of average lead to different results. Therefore, the ensamble average used in the standard kinetic theory (which usually is the phasic average) is suitable for the single realization, but not for several realization, as already pointed out in [5,6]. In the literature, three main length scales have been identified [7]: the smallest is the particles size, the intermediate consists in the local averaging (in order to describe some instability phenomena or secondary circulation) and the largest arises from phenomena such as large eddies in turbulence. Our aim is to solve the intermediate scale, by applying the mass weighted average, when dealing with more than one realizations. This statistical approach leads to additional diffusive terms in the continuity equation: starting from experimental

Effects of gauge volume on pseudo-strain induced in strain measurement using time-of-flight neutron diffraction

International Nuclear Information System (INIS)

Suzuki, Hiroshi; Harjo, Stefanus; Abe, Jun; Xu, Pingguang; Aizawa, Kazuya; Akita, Koichi

2013-01-01

Spurious or pseudo-strains observed in time-of-flight (TOF) neutron diffraction due to neutron attenuation, surface-effects and a strain distribution within the gauge volume were investigated. Experiments were carried out on annealed and bent ferritic steel bars to test these effects. The most representative position in the gauge volume corresponds to the neutron-weighted center of gravity (ncog), which takes into account variations in intensity within the gauge volume due to neutron attenuation and/or absence of material in the gauge volume. The average strain in the gauge volume was observed to be weighted towards the ncog position but following an increase in the size of the gauge volume the weighted average strain was changed because of the change in the ncog position when a strain gradient appeared within the gauge volume. On the other hand, typical pseudo-strains, which are well known, did appear in through-surface strain measurements when the gauge volume was incompletely filled by the sample. Tensile pseudo-strains due to the surface-effect increased near the sample surface and exhibited a similar trend regardless of the size of the gauge volume, while the pseudo-strains increased faster for the smaller gauge volume. Furthermore, a pseudo-strain due to a change in the ncog position was observed even when the gauge volume was perfectly filled in the sample, and it increased with an increase in the size of the gauge volume. These pseudo-strains measured were much larger than those simulated by the conventional modeling, whereas they were simulated by taking into account an incident neutron beam divergence additionally in the model. Therefore, the incident divergence of the incident neutron beam must be carefully designed to avoid pseudo-strains in time-of-flight neutron diffractometry

Increasing the Accuracy of Volume and ADC Delineation for Heterogeneous Tumor on Diffusion-Weighted MRI: Correlation with PET/CT

Energy Technology Data Exchange (ETDEWEB)

Gong, Nan-Jie [Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Wong, Chun-Sing, E-mail: drcswong@gmail.com [Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Chu, Yiu-Ching [Department of Radiology, Kwong Wah Hospital, Hong Kong (China); Guo, Hua [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing (China); Huang, Bingsheng [Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Chan, Queenie [Philips Healthcare, Hong Kong (China)

2013-10-01

Purpose: To improve the accuracy of volume and apparent diffusion coefficient (ADC) measurements in diffusion-weighted magnetic resonance imaging (MRI), we proposed a method based on thresholding both the b0 images and the ADC maps. Methods and Materials: In 21 heterogeneous lesions from patients with metastatic gastrointestinal stromal tumors (GIST), gross lesion were manually contoured, and corresponding volumes and ADCs were denoted as gross tumor volume (GTV) and gross ADC (ADC{sub g}), respectively. Using a k-means clustering algorithm, the probable high-cellularity tumor tissues were selected based on b0 images and ADC maps. ADC and volume of the tissues selected using the proposed method were denoted as thresholded ADC (ADC{sub thr}) and high-cellularity tumor volume (HCTV), respectively. The metabolic tumor volume (MTV) in positron emission tomography (PET)/computed tomography (CT) was measured using 40% maximum standard uptake value (SUV{sub max}) as the lower threshold, and corresponding mean SUV (SUV{sub mean}) was also measured. Results: HCTV had excellent concordance with MTV according to Pearson's correlation (r=0.984, P<.001) and linear regression (slope = 1.085, intercept = −4.731). In contrast, GTV overestimated the volume and differed significantly from MTV (P=.005). ADC{sub thr} correlated significantly and strongly with SUV{sub mean} (r=−0.807, P<.001) and SUV{sub max} (r=−0.843, P<.001); both were stronger than those of ADC{sub g}. Conclusions: The proposed lesion-adaptive semiautomatic method can help segment high-cellularity tissues that match hypermetabolic tissues in PET/CT and enables more accurate volume and ADC delineation on diffusion-weighted MR images of GIST.

The effect of wind shielding and pen position on the average daily weight gain and feed conversion rate of grower/finisher pigs

DEFF Research Database (Denmark)

Jensen, Dan B.; Toft, Nils; Cornou, Cécile

2014-01-01

of the effects of wind shielding, linear mixed models were fitted to describe the average daily weight gain and feed conversion rate of 1271 groups (14 individuals per group) of purebred Duroc, Yorkshire and Danish Landrace boars, as a function of shielding (yes/no), insert season (winter, spring, summer, autumn...... groups placed in the 1st and 4th pen (p=0.0001). A similar effect was not seen on smaller pigs. Pen placement appears to have no effect on feed conversion rate.No interaction effects between shielding and distance to the corridor could be demonstrated. Furthermore, in models including both factors......). The effect could not be tested for Yorkshire and Danish Landrace due to lack of data on these breeds. For groups of pigs above the average start weight, a clear tendency of higher growth rates at greater distances from the central corridor was observed, with the most significant differences being between...

SU-D-213-04: Accounting for Volume Averaging and Material Composition Effects in An Ionization Chamber Array for Patient Specific QA

International Nuclear Information System (INIS)

Fugal, M; McDonald, D; Jacqmin, D; Koch, N; Ellis, A; Peng, J; Ashenafi, M; Vanek, K

2015-01-01

Purpose: This study explores novel methods to address two significant challenges affecting measurement of patient-specific quality assurance (QA) with IBA’s Matrixx Evolution™ ionization chamber array. First, dose calculation algorithms often struggle to accurately determine dose to the chamber array due to CT artifact and algorithm limitations. Second, finite chamber size and volume averaging effects cause additional deviation from the calculated dose. Methods: QA measurements were taken with the Matrixx positioned on the treatment table in a solid-water Multi-Cube™ phantom. To reduce the effect of CT artifact, the Matrixx CT image set was masked with appropriate materials and densities. Individual ionization chambers were masked as air, while the high-z electronic backplane and remaining solid-water material were masked as aluminum and water, respectively. Dose calculation was done using Varian’s Acuros XB™ (V11) algorithm, which is capable of predicting dose more accurately in non-biologic materials due to its consideration of each material’s atomic properties. Finally, the exported TPS dose was processed using an in-house algorithm (MATLAB) to assign the volume averaged TPS dose to each element of a corresponding 2-D matrix. This matrix was used for comparison with the measured dose. Square fields at regularly-spaced gantry angles, as well as selected patient plans were analyzed. Results: Analyzed plans showed improved agreement, with the average gamma passing rate increasing from 94 to 98%. Correction factors necessary for chamber angular dependence were reduced by 67% compared to factors measured previously, indicating that previously measured factors corrected for dose calculation errors in addition to true chamber angular dependence. Conclusion: By comparing volume averaged dose, calculated with a capable dose engine, on a phantom masked with correct materials and densities, QA results obtained with the Matrixx Evolution™ can be significantly

Combining forecast weights: Why and how?

Science.gov (United States)

Yin, Yip Chee; Kok-Haur, Ng; Hock-Eam, Lim

2012-09-01

This paper proposes a procedure called forecast weight averaging which is a specific combination of forecast weights obtained from different methods of constructing forecast weights for the purpose of improving the accuracy of pseudo out of sample forecasting. It is found that under certain specified conditions, forecast weight averaging can lower the mean squared forecast error obtained from model averaging. In addition, we show that in a linear and homoskedastic environment, this superior predictive ability of forecast weight averaging holds true irrespective whether the coefficients are tested by t statistic or z statistic provided the significant level is within the 10% range. By theoretical proofs and simulation study, we have shown that model averaging like, variance model averaging, simple model averaging and standard error model averaging, each produces mean squared forecast error larger than that of forecast weight averaging. Finally, this result also holds true marginally when applied to business and economic empirical data sets, Gross Domestic Product (GDP growth rate), Consumer Price Index (CPI) and Average Lending Rate (ALR) of Malaysia.

Electrical method for the measurements of volume averaged electron density and effective coupled power to the plasma bulk

Science.gov (United States)

Henault, M.; Wattieaux, G.; Lecas, T.; Renouard, J. P.; Boufendi, L.

2016-02-01

Nanoparticles growing or injected in a low pressure cold plasma generated by a radiofrequency capacitively coupled capacitive discharge induce strong modifications in the electrical parameters of both plasma and discharge. In this paper, a non-intrusive method, based on the measurement of the plasma impedance, is used to determine the volume averaged electron density and effective coupled power to the plasma bulk. Good agreements are found when the results are compared to those given by other well-known and established methods.

Volume weighting the measure of the universe from classical slow-roll expansion

Science.gov (United States)

Sloan, David; Silk, Joseph

2016-05-01

One of the most frustrating issues in early universe cosmology centers on how to reconcile the vast choice of universes in string theory and in its most plausible high energy sibling, eternal inflation, which jointly generate the string landscape with the fine-tuned and hence relatively small number of universes that have undergone a large expansion and can accommodate observers and, in particular, galaxies. We show that such observations are highly favored for any system whereby physical parameters are distributed at a high energy scale, due to the conservation of the Liouville measure and the gauge nature of volume, asymptotically approaching a period of large isotropic expansion characterized by w =-1 . Our interpretation predicts that all observational probes for deviations from w =-1 in the foreseeable future are doomed to failure. The purpose of this paper is not to introduce a new measure for the multiverse, but rather to show how what is perhaps the most natural and well-known measure, volume weighting, arises as a consequence of the conservation of the Liouville measure on phase space during the classical slow-roll expansion.

Application of average adult Japanese voxel phantoms to evaluation of photon specific absorbed fractions

International Nuclear Information System (INIS)

Sato, Kaoru; Manabe, Kentaro; Endo, Akira

2012-01-01

Average adult Japanese male (JM-103) and female (JF-103) voxel (volume pixel) phantoms newly constructed at the Japan Atomic Energy Agency (JAEA) have average characteristics of body sizes and organ masses in adult Japanese. In JM-103 and JF-103, several organs and tissues were newly modeled for dose assessments based on tissue weighting factors of the 2007 Recommendations of the International Commission on Radiological Protection(ICRP). In this study, SAFs for thyroid, stomach, lungs and lymphatic nodes of JM-103 and JF-103 phantoms were calculated, and were compared with those of other adult Japanese phantoms based on individual medical images. In most cases, differences in SAFs between JM-103, JF-103 and other phantoms were about several tens percent, and was mainly attributed to mass differences of organs, tissues and contents. Therefore, it was concluded that SAFs of JM-103 and JF-103 represent those of average adult Japanese and that the two phantoms are applied to dose assessment for average adult Japanese on the basis of the 2007 Recommendations. (author)

Accuracy of DXA scanning of the thoracic spine: cadaveric studies comparing BMC, areal BMD and geometric estimates of volumetric BMD against ash weight and CT measures of bone volume.

Science.gov (United States)

Sran, Meena M; Khan, Karim M; Keiver, Kathy; Chew, Jason B; McKay, Heather A; Oxland, Thomas R

2005-12-01

Biomechanical studies of the thoracic spine often scan cadaveric segments by dual energy X-ray absorptiometry (DXA) to obtain measures of bone mass. Only one study has reported the accuracy of lateral scans of thoracic vertebral bodies. The accuracy of DXA scans of thoracic spine segments and of anterior-posterior (AP) thoracic scans has not been investigated. We have examined the accuracy of AP and lateral thoracic DXA scans by comparison with ash weight, the gold-standard for measuring bone mineral content (BMC). We have also compared three methods of estimating volumetric bone mineral density (vBMD) with a novel standard-ash weight (g)/bone volume (cm3) as measured by computed tomography (CT). Twelve T5-T8 spine segments were scanned with DXA (AP and lateral) and CT. The T6 vertebrae were excised, the posterior elements removed and then the vertebral bodies were ashed in a muffle furnace. We proposed a new method of estimating vBMD and compared it with two previously published methods. BMC values from lateral DXA scans displayed the strongest correlation with ash weight (r=0.99) and were on average 12.8% higher (pBMC (AP or lateral) was more strongly correlated with ash weight than areal bone mineral density (aBMD; AP: r=0.54, or lateral: r=0.71) or estimated vBMD. Estimates of vBMD with either of the three methods were strongly and similarly correlated with volumetric BMD calculated by dividing ash weight by CT-derived volume. These data suggest that readily available DXA scanning is an appropriate surrogate measure for thoracic spine bone mineral and that the lateral scan might be the scan method of choice.

SENSITIVITY ANALYSIS OF ORDERED WEIGHTED AVERAGING OPERATOR IN EARTHQUAKE VULNERABILITY ASSESSMENT

Directory of Open Access Journals (Sweden)

M. Moradi

2013-09-01

Full Text Available The main objective of this research is to find the extent to which the minimal variability Ordered Weighted Averaging (OWA model of seismic vulnerability assessment is sensitive to variation of optimism degree. There are a variety of models proposed for seismic vulnerability assessment. In order to examine the efficiency of seismic vulnerability assessment models, the stability of results could be analysed. Seismic vulnerability assessment is done to estimate the probable losses in the future earthquake. Multi-Criteria Decision Making (MCDM methods have been applied by a number of researchers to estimate the human, physical and financial losses in urban areas. The study area of this research is Tehran Metropolitan Area (TMA which has more than eight million inhabitants. In addition, this paper assumes that North Tehran Fault (NTF is activated and caused an earthquake in TMA. 1996 census data is used to extract the attribute values for six effective criteria in seismic vulnerability assessment. The results demonstrate that minimal variability OWA model of Seismic Loss Estimation (SLE is more stable where the aggregated seismic vulnerability degree has a lower value. Moreover, minimal variability OWA is very sensitive to optimism degree in northern areas of Tehran. A number of statistical units in southern areas of the city also indicate considerable sensitivity to optimism degree due to numerous non-standard buildings. In addition, the change of seismic vulnerability degree caused by variation of optimism degree does not exceed 25 % of the original value which means that the overall accuracy of the model is acceptable.

An upscaled two-equation model of transport in porous media through unsteady-state closure of volume averaged formulations

Science.gov (United States)

Chaynikov, S.; Porta, G.; Riva, M.; Guadagnini, A.

2012-04-01

We focus on a theoretical analysis of nonreactive solute transport in porous media through the volume averaging technique. Darcy-scale transport models based on continuum formulations typically include large scale dispersive processes which are embedded in a pore-scale advection diffusion equation through a Fickian analogy. This formulation has been extensively questioned in the literature due to its inability to depict observed solute breakthrough curves in diverse settings, ranging from the laboratory to the field scales. The heterogeneity of the pore-scale velocity field is one of the key sources of uncertainties giving rise to anomalous (non-Fickian) dispersion in macro-scale porous systems. Some of the models which are employed to interpret observed non-Fickian solute behavior make use of a continuum formulation of the porous system which assumes a two-region description and includes a bimodal velocity distribution. A first class of these models comprises the so-called ''mobile-immobile'' conceptualization, where convective and dispersive transport mechanisms are considered to dominate within a high velocity region (mobile zone), while convective effects are neglected in a low velocity region (immobile zone). The mass exchange between these two regions is assumed to be controlled by a diffusive process and is macroscopically described by a first-order kinetic. An extension of these ideas is the two equation ''mobile-mobile'' model, where both transport mechanisms are taken into account in each region and a first-order mass exchange between regions is employed. Here, we provide an analytical derivation of two region "mobile-mobile" meso-scale models through a rigorous upscaling of the pore-scale advection diffusion equation. Among the available upscaling methodologies, we employ the Volume Averaging technique. In this approach, the heterogeneous porous medium is supposed to be pseudo-periodic, and can be represented through a (spatially) periodic unit cell

SU-F-BRD-01: A Logistic Regression Model to Predict Objective Function Weights in Prostate Cancer IMRT

International Nuclear Information System (INIS)

Boutilier, J; Chan, T; Lee, T; Craig, T; Sharpe, M

2014-01-01

Purpose: To develop a statistical model that predicts optimization objective function weights from patient geometry for intensity-modulation radiotherapy (IMRT) of prostate cancer. Methods: A previously developed inverse optimization method (IOM) is applied retrospectively to determine optimal weights for 51 treated patients. We use an overlap volume ratio (OVR) of bladder and rectum for different PTV expansions in order to quantify patient geometry in explanatory variables. Using the optimal weights as ground truth, we develop and train a logistic regression (LR) model to predict the rectum weight and thus the bladder weight. Post hoc, we fix the weights of the left femoral head, right femoral head, and an artificial structure that encourages conformity to the population average while normalizing the bladder and rectum weights accordingly. The population average of objective function weights is used for comparison. Results: The OVR at 0.7cm was found to be the most predictive of the rectum weights. The LR model performance is statistically significant when compared to the population average over a range of clinical metrics including bladder/rectum V53Gy, bladder/rectum V70Gy, and mean voxel dose to the bladder, rectum, CTV, and PTV. On average, the LR model predicted bladder and rectum weights that are both 63% closer to the optimal weights compared to the population average. The treatment plans resulting from the LR weights have, on average, a rectum V70Gy that is 35% closer to the clinical plan and a bladder V70Gy that is 43% closer. Similar results are seen for bladder V54Gy and rectum V54Gy. Conclusion: Statistical modelling from patient anatomy can be used to determine objective function weights in IMRT for prostate cancer. Our method allows the treatment planners to begin the personalization process from an informed starting point, which may lead to more consistent clinical plans and reduce overall planning time

SU-F-BRD-01: A Logistic Regression Model to Predict Objective Function Weights in Prostate Cancer IMRT

Energy Technology Data Exchange (ETDEWEB)

Boutilier, J; Chan, T; Lee, T [University of Toronto, Toronto, Ontario (Canada); Craig, T; Sharpe, M [University of Toronto, Toronto, Ontario (Canada); The Princess Margaret Cancer Centre - UHN, Toronto, ON (Canada)

2014-06-15

Purpose: To develop a statistical model that predicts optimization objective function weights from patient geometry for intensity-modulation radiotherapy (IMRT) of prostate cancer. Methods: A previously developed inverse optimization method (IOM) is applied retrospectively to determine optimal weights for 51 treated patients. We use an overlap volume ratio (OVR) of bladder and rectum for different PTV expansions in order to quantify patient geometry in explanatory variables. Using the optimal weights as ground truth, we develop and train a logistic regression (LR) model to predict the rectum weight and thus the bladder weight. Post hoc, we fix the weights of the left femoral head, right femoral head, and an artificial structure that encourages conformity to the population average while normalizing the bladder and rectum weights accordingly. The population average of objective function weights is used for comparison. Results: The OVR at 0.7cm was found to be the most predictive of the rectum weights. The LR model performance is statistically significant when compared to the population average over a range of clinical metrics including bladder/rectum V53Gy, bladder/rectum V70Gy, and mean voxel dose to the bladder, rectum, CTV, and PTV. On average, the LR model predicted bladder and rectum weights that are both 63% closer to the optimal weights compared to the population average. The treatment plans resulting from the LR weights have, on average, a rectum V70Gy that is 35% closer to the clinical plan and a bladder V70Gy that is 43% closer. Similar results are seen for bladder V54Gy and rectum V54Gy. Conclusion: Statistical modelling from patient anatomy can be used to determine objective function weights in IMRT for prostate cancer. Our method allows the treatment planners to begin the personalization process from an informed starting point, which may lead to more consistent clinical plans and reduce overall planning time.

A mass-density model can account for the size-weight illusion

Science.gov (United States)

Bergmann Tiest, Wouter M.; Drewing, Knut

2018-01-01

When judging the heaviness of two objects with equal mass, people perceive the smaller and denser of the two as being heavier. Despite the large number of theories, covering bottom-up and top-down approaches, none of them can fully account for all aspects of this size-weight illusion and thus for human heaviness perception. Here we propose a new maximum-likelihood estimation model which describes the illusion as the weighted average of two heaviness estimates with correlated noise: One estimate derived from the object’s mass, and the other from the object’s density, with estimates’ weights based on their relative reliabilities. While information about mass can directly be perceived, information about density will in some cases first have to be derived from mass and volume. However, according to our model at the crucial perceptual level, heaviness judgments will be biased by the objects’ density, not by its size. In two magnitude estimation experiments, we tested model predictions for the visual and the haptic size-weight illusion. Participants lifted objects which varied in mass and density. We additionally varied the reliability of the density estimate by varying the quality of either visual (Experiment 1) or haptic (Experiment 2) volume information. As predicted, with increasing quality of volume information, heaviness judgments were increasingly biased towards the object’s density: Objects of the same density were perceived as more similar and big objects were perceived as increasingly lighter than small (denser) objects of the same mass. This perceived difference increased with an increasing difference in density. In an additional two-alternative forced choice heaviness experiment, we replicated that the illusion strength increased with the quality of volume information (Experiment 3). Overall, the results highly corroborate our model, which seems promising as a starting point for a unifying framework for the size-weight illusion and human heaviness

A mass-density model can account for the size-weight illusion.

Science.gov (United States)

Wolf, Christian; Bergmann Tiest, Wouter M; Drewing, Knut

2018-01-01

When judging the heaviness of two objects with equal mass, people perceive the smaller and denser of the two as being heavier. Despite the large number of theories, covering bottom-up and top-down approaches, none of them can fully account for all aspects of this size-weight illusion and thus for human heaviness perception. Here we propose a new maximum-likelihood estimation model which describes the illusion as the weighted average of two heaviness estimates with correlated noise: One estimate derived from the object's mass, and the other from the object's density, with estimates' weights based on their relative reliabilities. While information about mass can directly be perceived, information about density will in some cases first have to be derived from mass and volume. However, according to our model at the crucial perceptual level, heaviness judgments will be biased by the objects' density, not by its size. In two magnitude estimation experiments, we tested model predictions for the visual and the haptic size-weight illusion. Participants lifted objects which varied in mass and density. We additionally varied the reliability of the density estimate by varying the quality of either visual (Experiment 1) or haptic (Experiment 2) volume information. As predicted, with increasing quality of volume information, heaviness judgments were increasingly biased towards the object's density: Objects of the same density were perceived as more similar and big objects were perceived as increasingly lighter than small (denser) objects of the same mass. This perceived difference increased with an increasing difference in density. In an additional two-alternative forced choice heaviness experiment, we replicated that the illusion strength increased with the quality of volume information (Experiment 3). Overall, the results highly corroborate our model, which seems promising as a starting point for a unifying framework for the size-weight illusion and human heaviness perception.

Influence of shear flow on the specific volume and the crystalline morphology of isotactic polypropylene

NARCIS (Netherlands)

van der Beek, M.H.E.; Peters, G.W.M.; Meijer, H.E.H.

2006-01-01

The influence of shear flow on the temperature evolution of the specific volume and the crystalline morphology of two iPP's, differing in weight-averaged molar mass w, was investigated at nonisothermal conditions and elevated pressures, using a custom-designed dilatometer. These conditions are

Global and regional brain volumes normalization in weight-recovered adolescents with anorexia nervosa: preliminary findings of a longitudinal voxel-based morphometry study

Directory of Open Access Journals (Sweden)

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

Anthropometric parameters: weight height, body mass index and mammary volume in relationship with the mammographic pattern

International Nuclear Information System (INIS)

Perez-Candela, V.; Busto, C.; Avila, R.; Marrero, M. G.; Liminana, J. M.; Orengo, J. C.

2001-01-01

A prospective study to attempt to relate the anthropometric parameters of height, weight, body mass index as well as age with the mammographic patterns obtained for the patients and obtain an anthropometric profile was carried out. The study was performed in 1.000 women who underwent a mammography in cranial-caudal and medial lateral oblique projection of both breasts, independently of whether they were screened or diagnosed. Prior to the performance of the mammography, weight and height were obtained, and this was also performed by the same technicians, and the patient were asked their bra size to deduce breast volume. With the weight, the body mass index of Quetelet was calculated (weight [kg]/height''2 (ml). After reading the mammography, the patient was assigned to one of the four mammographic patterns considered in the BIRADS (Breast Imaging Reporting and Data System) established by the ACR (American College of Radiology): type I (fat). type II (disperse fibroglandular densities), type III (fibroglandular densities distributed heterogeneously), type 4 (dense). The results were introduced into a computer database and the SPSS 8.0 statistical program was applied, using the statistical model of multivariant logistic regression. In women under 40 years, with normal weight, the dense breast pattern accounted for 67.8% and as the body mass index (BMI) increased, this pattern decreased to 25.1%. The fat pattern is 20% and as the BMI increases, this increased to 80%. In 40-60 year old women with normal weight, the dense pattern accounts for 44% and decreases to 20.9% in the grades II, III and IV obese. The fat pattern is 11.1% and increases to 53.7% in the grade II, III and IV obese. In women over 60 with normal, the dense pattern accounts for 19.3% and and decreases to 13% in the grade III obese. The fat pattern is 5.3% and increases to 20.2% in the grade iii of obesity. As age increases, the probability of presenting a mammographic pattern with a fat image in the

All rights reserved Variation in Body Weight, Organ Weight and ...

African Journals Online (AJOL)

ADOWIE PERE

Variation in Body Weight, Organ Weight and Haematological Parameters of Rats Fed ... ABSTRACT: Food insecurity is a major problem of the developing nations. ... Except for the values of haemoglobin and packed cell volume that were ...

The effect of temperature on the average volume of Barkhausen jump on Q235 carbon steel

Science.gov (United States)

Guo, Lei; Shu, Di; Yin, Liang; Chen, Juan; Qi, Xin

2016-06-01

On the basis of the average volume of Barkhausen jump (AVBJ) vbar generated by irreversible displacement of magnetic domain wall under the effect of the incentive magnetic field on ferromagnetic materials, the functional relationship between saturation magnetization Ms and temperature T is employed in this paper to deduce the explicit mathematical expression among AVBJ vbar, stress σ, incentive magnetic field H and temperature T. Then the change law between AVBJ vbar and temperature T is researched according to the mathematical expression. Moreover, the tensile and compressive stress experiments are carried out on Q235 carbon steel specimens at different temperature to verify our theories. This paper offers a series of theoretical bases to solve the temperature compensation problem of Barkhausen testing method.

40 CFR 80.205 - How is the annual refinery or importer average and corporate pool average sulfur level determined?

Science.gov (United States)

2010-07-01

... volume of gasoline produced or imported in batch i. Si=The sulfur content of batch i determined under § 80.330. n=The number of batches of gasoline produced or imported during the averaging period. i=Individual batch of gasoline produced or imported during the averaging period. (b) All annual refinery or...

Prediction of infarction and reperfusion in stroke by flow- and volume-weighted collateral signal in MR angiography.

Science.gov (United States)

Ernst, M; Forkert, N D; Brehmer, L; Thomalla, G; Siemonsen, S; Fiehler, J; Kemmling, A

2015-02-01

In proximal anterior circulation occlusive strokes, collateral flow is essential for good outcome. Collateralized vessel intensity in TOF- and contrast-enhanced MRA is variable due to different acquisition methods. Our purpose was to quantify collateral supply by using flow-weighted signal in TOF-MRA and blood volume-weighted signal in contrast-enhanced MRA to determine each predictive contribution to tissue infarction and reperfusion. Consecutively (2009-2013), 44 stroke patients with acute proximal anterior circulation occlusion met the inclusion criteria with TOF- and contrast-enhanced MRA and penumbral imaging. Collateralized vessels in the ischemic hemisphere were assessed by TOF- and contrast-enhanced MRA using 2 methods: 1) visual 3-point collateral scoring, and 2) collateral signal quantification by an arterial atlas-based collateral index. Collateral measures were tested by receiver operating characteristic curve and logistic regression against 2 imaging end points of tissue-outcome: final infarct volume and percentage of penumbra saved. Visual collateral scores on contrast-enhanced MRA but not TOF were significantly higher in patients with good outcome. Visual collateral scoring on contrast-enhanced MRA was the best rater-based discriminator for final infarct volume 50% (area under the curve, 0.67; P = .04). Atlas-based collateral index of contrast-enhanced MRA was the overall best independent discriminator for final infarct volume of collateral index combining the signal of TOF- and contrast-enhanced MRA was the overall best discriminator for effective reperfusion (percentage of penumbra saved >50%; area under the curve, 0.89; P collateral assessment, TOF- and contrast-enhanced MRA both contain predictive signal information for penumbral reperfusion. This could improve risk stratification in further studies. © 2015 by American Journal of Neuroradiology.

A highly detailed FEM volume conductor model based on the ICBM152 average head template for EEG source imaging and TCS targeting.

Science.gov (United States)

Haufe, Stefan; Huang, Yu; Parra, Lucas C

2015-08-01

In electroencephalographic (EEG) source imaging as well as in transcranial current stimulation (TCS), it is common to model the head using either three-shell boundary element (BEM) or more accurate finite element (FEM) volume conductor models. Since building FEMs is computationally demanding and labor intensive, they are often extensively reused as templates even for subjects with mismatching anatomies. BEMs can in principle be used to efficiently build individual volume conductor models; however, the limiting factor for such individualization are the high acquisition costs of structural magnetic resonance images. Here, we build a highly detailed (0.5mm(3) resolution, 6 tissue type segmentation, 231 electrodes) FEM based on the ICBM152 template, a nonlinear average of 152 adult human heads, which we call ICBM-NY. We show that, through more realistic electrical modeling, our model is similarly accurate as individual BEMs. Moreover, through using an unbiased population average, our model is also more accurate than FEMs built from mismatching individual anatomies. Our model is made available in Matlab format.

Global (volume-averaged) model of inductively coupled chlorine plasma : influence of Cl wall recombination and external heating on continuous and pulse-modulated plasmas

NARCIS (Netherlands)

Kemaneci, E.H.; Carbone, E.A.D.; Booth, J.P.; Graef, W.A.A.D.; Dijk, van J.; Kroesen, G.M.W.

An inductively coupled radio-frequency plasma in chlorine is investigated via a global (volume-averaged) model, both in continuous and square wave modulated power input modes. After the power is switched off (in a pulsed mode) an ion–ion plasma appears. In order to model this phenomenon, a novel

Average Bandwidth Allocation Model of WFQ

Directory of Open Access Journals (Sweden)

Tomáš Balogh

2012-01-01

Full Text Available We present a new iterative method for the calculation of average bandwidth assignment to traffic flows using a WFQ scheduler in IP based NGN networks. The bandwidth assignment calculation is based on the link speed, assigned weights, arrival rate, and average packet length or input rate of the traffic flows. We prove the model outcome with examples and simulation results using NS2 simulator.

A randomised clinical trial on the efficacy of oxytetracycline dose through water medication of nursery pigs on diarrhoea, faecal shedding of Lawsonia intracellularis and average daily weight gain

DEFF Research Database (Denmark)

Larsen, Inge-Lise; Hjulsager, Charlotte Kristiane; Holm, Anders

2016-01-01

the efficacy of three oral dosage regimens (5, 10 and 20mg/kg body weight) of oxytetracycline (OTC) in drinking water over a five-day period on diarrhoea, faecal shedding of LI and average daily weight gain (ADG). A randomised clinical trial was carried out in four Danish pig herds. In total, 539 animals from...

Positive outcome of average volume-assured pressure support mode of a Respironics V60 Ventilator in acute exacerbation of chronic obstructive pulmonary disease: a case report

Directory of Open Access Journals (Sweden)

Okuda Miyuki

2012-09-01

Full Text Available Abstract Introduction We were able to treat a patient with acute exacerbation of chronic obstructive pulmonary disease who also suffered from sleep-disordered breathing by using the average volume-assured pressure support mode of a Respironics V60 Ventilator (Philips Respironics: United States. This allows a target tidal volume to be set based on automatic changes in inspiratory positive airway pressure. This removed the need to change the noninvasive positive pressure ventilation settings during the day and during sleep. The Respironics V60 Ventilator, in the average volume-assured pressure support mode, was attached to our patient and improved and stabilized his sleep-related hypoventilation by automatically adjusting force to within an acceptable range. Case presentation Our patient was a 74-year-old Japanese man who was hospitalized for treatment due to worsening of dyspnea and hypoxemia. He was diagnosed with acute exacerbation of chronic obstructive pulmonary disease and full-time biphasic positive airway pressure support ventilation was initiated. Our patient was temporarily provided with portable noninvasive positive pressure ventilation at night-time following an improvement in his condition, but his chronic obstructive pulmonary disease again worsened due to the recurrence of a respiratory infection. During the initial exacerbation, his tidal volume was significantly lower during sleep (378.9 ± 72.9mL than while awake (446.5 ± 63.3mL. A ventilator that allows ventilation to be maintained by automatically adjusting the inspiratory force to within an acceptable range was attached in average volume-assured pressure support mode, improving his sleep-related hypoventilation, which is often associated with the use of the Respironics V60 Ventilator. Polysomnography performed while our patient was on noninvasive positive pressure ventilation revealed obstructive sleep apnea syndrome (apnea-hypopnea index = 14, suggesting that his chronic

Weight control behaviors of highly successful weight loss maintainers: the Portuguese Weight Control Registry.

Science.gov (United States)

Santos, Inês; Vieira, Paulo N; Silva, Marlene N; Sardinha, Luís B; Teixeira, Pedro J

2017-04-01

To describe key behaviors reported by participants in the Portuguese Weight Control Registry and to determine associations between these behaviors and weight loss maintenance. A total of 388 adults participated in this cross-sectional study. Assessments included demographic information, weight history, weight loss and weight maintenance strategies, dietary intake, and physical activity. Participants lost on average 18 kg, which they had maintained for ~28 months. Their average dietary intake was 2199 kcal/day, with 33 % of energy coming from fat. About 78 % of participants engaged in levels of moderate-plus-vigorous physical activity exceeding 150 min/week (51 % above 250 min/week), with men accumulating 82 more minutes than women (p breakfast. Greater weight loss maintenance was associated with higher levels of physical activity, walking, weight self-monitoring, establishing specific goals, and with reduced portion size use, reduced consumption of carbohydrates, and increased consumption of protein, (p < 0.05). Results indicate that weight loss maintenance is possible through the adoption of a nutritionally-balanced diet and regular participation in physical activity, but also suggest that adopting different (and, to a degree, individualized) set of behavioral strategies is key for achieving success.

Bounds on Average Time Complexity of Decision Trees

KAUST Repository

Chikalov, Igor

2011-01-01

In this chapter, bounds on the average depth and the average weighted depth of decision trees are considered. Similar problems are studied in search theory [1], coding theory [77], design and analysis of algorithms (e.g., sorting) [38]. For any

Bone marrow response in treated patients with Gaucher disease: evaluation by T1-weighted magnetic resonance images and correlation with reduction in liver and spleen volume

International Nuclear Information System (INIS)

Terk, M.R.; Dardashti, S.; Liebman, H.A.

2000-01-01

Purpose. To determine whether T1-weighted magnetic resonance (MR) images can demonstrate response in the marrow of patients with type 1 Gaucher disease treated with enzyme replacement therapy (ERT) and to determine whether a relationship exists between liver and spleen volume reductions and visible marrow changes.Patients. Forty-two patients with type 1 Gaucher disease were evaluated on at least two occasions. Thirty-two patients received ERT. Of these patients, 15 had a baseline examination prior to the initiation of ERT. The remaining 10 patients did not receive ERT.Design. T1-weighted and gradient recalled echo (GRE) coronal images of the femurs and hips were obtained. Concurrently, liver and spleen volumes were determined using contiguous breath-hold axial gradient-echo images. T1-weighted images of the hips and femurs were evaluated to determine change or lack of change in the yellow marrow.Results. Of the 32 patients receiving ERT, 14 (44%) demonstrated increased signal on T1-weighted images suggesting an increase in the amount of yellow marrow. If only the 15 patients with a baseline examination were considered, the response rate to ERT was 67%. Using Student's t-test a highly significant correlation (P<0.005) was found between marrow response and reduction in liver and spleen volume.Conclusions. Marrow changes in patients receiving ERT can be detected by T1-weighted images. This response correlated with reductions in visceral volumes (P<0.0005). (orig.)

The influence of poly(acrylic) acid number average molecular weight and concentration in solution on the compressive fracture strength and modulus of a glass-ionomer restorative.

LENUS (Irish Health Repository)

Dowling, Adam H

2011-06-01

The aim was to investigate the influence of number average molecular weight and concentration of the poly(acrylic) acid (PAA) liquid constituent of a GI restorative on the compressive fracture strength (σ) and modulus (E).

Measurement of brain perfusion, blood volume, and blood-brain barrier permeability, using dynamic contrast-enhanced T(1)-weighted MRI at 3 tesla

DEFF Research Database (Denmark)

Larsson, Henrik B W; Courivaud, Frédéric; Rostrup, Egill

2009-01-01

Assessment of vascular properties is essential to diagnosis and follow-up and basic understanding of pathogenesis in brain tumors. In this study, a procedure is presented that allows concurrent estimation of cerebral perfusion, blood volume, and blood-brain permeability from dynamic T(1)-weighted...... on a pixel-by-pixel basis of cerebral perfusion, cerebral blood volume, and blood-brain barrier permeability.......Assessment of vascular properties is essential to diagnosis and follow-up and basic understanding of pathogenesis in brain tumors. In this study, a procedure is presented that allows concurrent estimation of cerebral perfusion, blood volume, and blood-brain permeability from dynamic T(1)-weighted...... imaging of a bolus of a paramagnetic contrast agent passing through the brain. The methods are applied in patients with brain tumors and in healthy subjects. Perfusion was estimated by model-free deconvolution using Tikhonov's method (gray matter/white matter/tumor: 72 +/- 16/30 +/- 8/56 +/- 45 mL/100 g...

A system dynamics optimization framework to achieve population desired of average weight target

Science.gov (United States)

Abidin, Norhaslinda Zainal; Zulkepli, Jafri Haji; Zaibidi, Nerda Zura

2017-11-01

Obesity is becoming a serious problem in Malaysia as it has been rated as the highest among Asian countries. The aim of the paper is to propose a system dynamics (SD) optimization framework to achieve population desired weight target based on the changes in physical activity behavior and its association to weight and obesity. The system dynamics approach of stocks and flows diagram was used to quantitatively model the impact of both behavior on the population's weight and obesity trends. This work seems to bring this idea together and highlighting the interdependence of the various aspects of eating and physical activity behavior on the complex of human weight regulation system. The model was used as an experimentation vehicle to investigate the impacts of changes in physical activity on weight and prevalence of obesity implications. This framework paper provides evidence on the usefulness of SD optimization as a strategic decision making approach to assist in decision making related to obesity prevention. SD applied in this research is relatively new in Malaysia and has a high potential to apply to any feedback models that address the behavior cause to obesity.

Application of volume-weighted skew-upwind differencing to thermal and fluid mixing in the cold leg and downcomer of a PWR

International Nuclear Information System (INIS)

Chen, F.F.; Miao, C.C.; Chen, B.C.J.; Domanus, H.M.; Lyczkowski, R.W.; Sha, W.T.

1983-01-01

Upwind differencing has been the most common numerical scheme used in computational fluid flow and heat transfer in past years. However, the numerical diffusion induced by the use of upwind differencing can be significant in problems involving thermal mixing. Thermal and fluid mixing in a pressurized water reactor during high pressurized coolant injection is a typical example where numerical diffusion is significant. An improved volume-weighted skew-upwind differencing is used here to reduce numerical diffusion without overshooting or undershooting which is the major defect of original skew-upwind differencing proposed by Raithby. The basic concept of volume-weighted skew-upwind differencing is shown. Computations were performed using COMMIX-1B, an extended version of the COMMIX-1A. The experiment analyzed here is test No. 1 of the SAI experiment

Dosimetric consequences of planning lung treatments on 4DCT average reconstruction to represent a moving tumour

International Nuclear Information System (INIS)

Dunn, L.F.; Taylor, M.L.; Kron, T.; Franich, R.

2010-01-01

Full text: Anatomic motion during a radiotherapy treatment is one of the more significant challenges in contemporary radiation therapy. For tumours of the lung, motion due to patient respiration makes both accurate planning and dose delivery difficult. One approach is to use the maximum intensity projection (MIP) obtained from a 40 computed tomography (CT) scan and then use this to determine the treatment volume. The treatment is then planned on a 4DCT average reco struction, rather than assuming the entire ITY has a uniform tumour density. This raises the question: how well does planning on a 'blurred' distribution of density with CT values greater than lung density but less than tumour density match the true case of a tumour moving within lung tissue? The aim of this study was to answer this question, determining the dosimetric impact of using a 4D-CT average reconstruction as the basis for a radiotherapy treatment plan. To achieve this, Monte-Carlo sim ulations were undertaken using GEANT4. The geometry consisted of a tumour (diameter 30 mm) moving with a sinusoidal pattern of amplitude = 20 mm. The tumour's excursion occurs within a lung equivalent volume beyond a chest wall interface. Motion was defined parallel to a 6 MY beam. This was then compared to a single oblate tumour of a magnitude determined by the extremes of the tumour motion. The variable density of the 4DCT average tumour is simulated by a time-weighted average, to achieve the observed density gradient. The generic moving tumour geometry is illustrated in the Figure.

Interpreting Bivariate Regression Coefficients: Going beyond the Average

Science.gov (United States)

Halcoussis, Dennis; Phillips, G. Michael

2010-01-01

Statistics, econometrics, investment analysis, and data analysis classes often review the calculation of several types of averages, including the arithmetic mean, geometric mean, harmonic mean, and various weighted averages. This note shows how each of these can be computed using a basic regression framework. By recognizing when a regression model…

Generation of the covariance matrix for a set of nuclear data produced by collapsing a larger parent set through the weighted averaging of equivalent data points

International Nuclear Information System (INIS)

Smith, D.L.

1987-01-01

A method is described for generating the covariance matrix of a set of experimental nuclear data which has been collapsed in size by the averaging of equivalent data points belonging to a larger parent data set. It is assumed that the data values and covariance matrix for the parent set are provided. The collapsed set is obtained by a proper weighted-averaging procedure based on the method of least squares. It is then shown by means of the law of error propagation that the elements of the covariance matrix for the collapsed set are linear combinations of elements from the parent set covariance matrix. The coefficients appearing in these combinations are binary products of the same coefficients which appear as weighting factors in the data collapsing procedure. As an example, the procedure is applied to a collection of recently-measured integral neutron-fission cross-section ratios. (orig.)

Low Goiter Rate Associated with Small Average Thyroid Volume in Schoolchildren after the Elimination of Iodine Deficiency Disorders.

Directory of Open Access Journals (Sweden)

Peihua Wang

Full Text Available After the implementation of the universal salt iodization (USI program in 1996, seven cross-sectional school-based surveys have been conducted to monitor iodine deficiency disorders (IDD among children in eastern China.This study aimed to examine the correlation of total goiter rate (TGR with average thyroid volume (Tvol and urinary iodine concentration (UIC in Jiangsu province after IDD elimination.Probability-proportional-to-size sampling was applied to select 1,200 children aged 8-10 years old in 30 clusters for each survey in 1995, 1997, 1999, 2001, 2002, 2005, 2009 and 2011. We measured Tvol using ultrasonography in 8,314 children and measured UIC (4,767 subjects and salt iodine (10,184 samples using methods recommended by the World Health Organization. Tvol was used to calculate TGR based on the reference criteria specified for sex and body surface area (BSA.TGR decreased from 55.2% in 1997 to 1.0% in 2009, and geometric means of Tvol decreased from 3.63 mL to 1.33 mL, along with the UIC increasing from 83 μg/L in 1995 to 407 μg/L in 1999, then decreasing to 243 μg/L in 2005, and then increasing to 345 μg/L in 2011. In the low goiter population (TGR 300 μg/L was associated with a smaller average Tvol in children.After IDD elimination in Jiangsu province in 2001, lower TGR was associated with smaller average Tvol. Average Tvol was more sensitive than TGR in detecting the fluctuation of UIC. A UIC of 300 μg/L may be defined as a critical value for population level iodine status monitoring.

A comparative analysis of 9 multi-model averaging approaches in hydrological continuous streamflow simulation

Science.gov (United States)

Arsenault, Richard; Gatien, Philippe; Renaud, Benoit; Brissette, François; Martel, Jean-Luc

2015-10-01

This study aims to test whether a weighted combination of several hydrological models can simulate flows more accurately than the models taken individually. In addition, the project attempts to identify the most efficient model averaging method and the optimal number of models to include in the weighting scheme. In order to address the first objective, streamflow was simulated using four lumped hydrological models (HSAMI, HMETS, MOHYSE and GR4J-6), each of which were calibrated with three different objective functions on 429 watersheds. The resulting 12 hydrographs (4 models × 3 metrics) were weighted and combined with the help of 9 averaging methods which are the simple arithmetic mean (SAM), Akaike information criterion (AICA), Bates-Granger (BGA), Bayes information criterion (BICA), Bayesian model averaging (BMA), Granger-Ramanathan average variant A, B and C (GRA, GRB and GRC) and the average by SCE-UA optimization (SCA). The same weights were then applied to the hydrographs in validation mode, and the Nash-Sutcliffe Efficiency metric was measured between the averaged and observed hydrographs. Statistical analyses were performed to compare the accuracy of weighted methods to that of individual models. A Kruskal-Wallis test and a multi-objective optimization algorithm were then used to identify the most efficient weighted method and the optimal number of models to integrate. Results suggest that the GRA, GRB, GRC and SCA weighted methods perform better than the individual members. Model averaging from these four methods were superior to the best of the individual members in 76% of the cases. Optimal combinations on all watersheds included at least one of each of the four hydrological models. None of the optimal combinations included all members of the ensemble of 12 hydrographs. The Granger-Ramanathan average variant C (GRC) is recommended as the best compromise between accuracy, speed of execution, and simplicity.

Anatomical and functional volume concordance between FDG PET, and T2 and diffusion-weighted MRI for cervical cancer: a hybrid PET/MR study

International Nuclear Information System (INIS)

Sun, Hongzan; Xin, Jun; Zhang, Shaomin; Guo, Qiyong; Lu, Yueyue; Zhai, Wei; Zhao, Long; Peng, Weiai; Wang, Baijun

2014-01-01

To evaluate the concordance among 18 F-FDG PET imaging, MR T2-weighted (T2-W) imaging and apparent diffusion coefficient (ADC) maps with diffusion-weighted (DW) imaging in cervical cancer using hybrid whole-body PET/MR. This study prospectively included 35 patients with cervical cancer who underwent pretreatment 18 F-FDG PET/MR imaging. 18 F-FDG PET and MR images were fused using standard software. The percent of the maximum standardized uptake values (SUV max ) was used to contour tumours on PET images, and volumes were calculated automatically. Tumour volumes measured on T2-W and DW images were calculated with standard techniques of tumour area multiplied by the slice profile. Parametric statistics were used for data analysis. FDG PET tumour volumes calculated using SUV max (14.30 ± 4.70) and T2-W imaging volume (33.81 ± 27.32 cm 3 ) were similar (P > 0.05) at 35 % and 40 % of SUV max (32.91 ± 18.90 cm 3 and 27.56 ± 17.19 cm 3 respectively) and significantly correlated (P 3 . DW volumes were not significantly different from FDG PET volumes at either 35 % SUV max or 40 % SUV max or from T2-W imaging volumes (P > 0.05). PET subvolumes with increasing SUV max cut-off percentage showed an inverse change in mean ADC values on DW imaging (P max is recommended for 18 F-FDG PET/MR SUV-based tumour volume estimation. The linear tumour subvolume concordance between FDG PET and DW imaging demonstrates individual regional concordance of metabolic activity and cell density. (orig.)

Improved longitudinal length accuracy of gross tumor volume delineation with diffusion weighted magnetic resonance imaging for esophageal squamous cell carcinoma

International Nuclear Information System (INIS)

Hou, Dong-Liang; Shi, Gao-Feng; Gao, Xian-Shu; Asaumi, Junichi; Li, Xue-Ying; Liu, Hui; Yao, Chen; Chang, Joe Y

2013-01-01

To analyze the longitudinal length accuracy of gross tumor volume (GTV) delineation with diffusion weighted magnetic resonance imaging for esophageal squamous cell carcinoma (SCC). Forty-two patients from December 2011 to June 2012 with esophageal SCC who underwent radical surgery were analyzed. Routine computed tomography (CT) scan, T2-weighted MRI and diffusion weighted magnetic resonance imaging (DWI) were employed before surgery. Diffusion-sensitive gradient b-values were taken at 400, 600, and 800 s/mm 2 . Gross tumor volumes (GTV) were delineated using CT, T2-weighted MRI and DWI on different b-value images. GTV longitude length measured using the imaging modalities listed above was compared with pathologic lesion length to determine the most accurate imaging modality. CMS Xio radiotherapy planning system was used to fuse DWI scans and CT images to investigate the possibility of delineating GTV on fused images. The differences between the GTV length according to CT, T2-weighted MRI and pathology were 3.63 ± 12.06 mm and 3.46 ± 11.41 mm, respectively. When the diffusion-sensitive gradient b-value was 400, 600, and 800 s/mm 2 , the differences between the GTV length using DWI and pathology were 0.73 ± 6.09 mm, -0.54 ± 6.03 mm and −1.58 ± 5.71 mm, respectively. DWI scans and CT images were fused accurately using the radiotherapy planning system. GTV margins were depicted clearly on fused images. DWI displays esophageal SCC lengths most precisely when compared with CT or regular MRI. DWI scans fused with CT images can be used to improve accuracy to delineate GTV in esophageal SCC

Prehospital tidal volume influences hospital tidal volume: A cohort study.

Science.gov (United States)

Stoltze, Andrew J; Wong, Terrence S; Harland, Karisa K; Ahmed, Azeemuddin; Fuller, Brian M; Mohr, Nicholas M

2015-06-01

The purposes of the study are to describe current practice of ventilation in a modern air medical system and to measure the association of ventilation strategy with subsequent ventilator care and acute respiratory distress syndrome (ARDS). Retrospective observational cohort study of intubated adult patients (n = 235) transported by a university-affiliated air medical transport service to a 711-bed tertiary academic center between July 2011 and May 2013. Low tidal volume ventilation was defined as tidal volumes less than or equal to 8 mL/kg predicted body weight. Multivariable regression was used to measure the association between prehospital tidal volume, hospital ventilation strategy, and ARDS. Most patients (57%) were ventilated solely with bag valve ventilation during transport. Mean tidal volume of mechanically ventilated patients was 8.6 mL/kg predicted body weight (SD, 0.2 mL/kg). Low tidal volume ventilation was used in 13% of patients. Patients receiving low tidal volume ventilation during air medical transport were more likely to receive low tidal volume ventilation in the emergency department (P tidal volume (P = .840). Low tidal volume ventilation was rare during air medical transport. Air transport ventilation strategy influenced subsequent ventilation but was not associated with ARDS. Copyright © 2015 Elsevier Inc. All rights reserved.

Estimating Loess Plateau Average Annual Precipitation with Multiple Linear Regression Kriging and Geographically Weighted Regression Kriging

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.

Estimation of standard liver volume in Chinese adult living donors.

Science.gov (United States)

Fu-Gui, L; Lu-Nan, Y; Bo, L; Yong, Z; Tian-Fu, W; Ming-Qing, X; Wen-Tao, W; Zhe-Yu, C

2009-12-01

To determine a formula predicting the standard liver volume based on body surface area (BSA) or body weight in Chinese adults. A total of 115 consecutive right-lobe living donors not including the middle hepatic vein underwent right hemi-hepatectomy. No organs were used from prisoners, and no subjects were prisoners. Donor anthropometric data including age, gender, body weight, and body height were recorded prospectively. The weights and volumes of the right lobe liver grafts were measured at the back table. Liver weights and volumes were calculated from the right lobe graft weight and volume obtained at the back table, divided by the proportion of the right lobe on computed tomography. By simple linear regression analysis and stepwise multiple linear regression analysis, we correlated calculated liver volume and body height, body weight, or body surface area. The subjects had a mean age of 35.97 +/- 9.6 years, and a female-to-male ratio of 60:55. The mean volume of the right lobe was 727.47 +/- 136.17 mL, occupying 55.59% +/- 6.70% of the whole liver by computed tomography. The volume of the right lobe was 581.73 +/- 96.137 mL, and the estimated liver volume was 1053.08 +/- 167.56 mL. Females of the same body weight showed a slightly lower liver weight. By simple linear regression analysis and stepwise multiple linear regression analysis, a formula was derived based on body weight. All formulae except the Hong Kong formula overestimated liver volume compared to this formula. The formula of standard liver volume, SLV (mL) = 11.508 x body weight (kg) + 334.024, may be applied to estimate liver volumes in Chinese adults.

Anatomical and functional volume concordance between FDG PET, and T2 and diffusion-weighted MRI for cervical cancer: a hybrid PET/MR study

Energy Technology Data Exchange (ETDEWEB)

Sun, Hongzan; Xin, Jun; Zhang, Shaomin; Guo, Qiyong; Lu, Yueyue; Zhai, Wei; Zhao, Long [Shengjing Hospital of China Medical University, Department of Radiology, Shenyang, Liaoning (China); Peng, Weiai [NM Marketing, Great China, Philips Healthcare, Guangzhou (China); Wang, Baijun [Philips China Investment Co. Ltd. Shenyang Office, Shenyang, Liaoning (China)

2014-05-15

To evaluate the concordance among {sup 18}F-FDG PET imaging, MR T2-weighted (T2-W) imaging and apparent diffusion coefficient (ADC) maps with diffusion-weighted (DW) imaging in cervical cancer using hybrid whole-body PET/MR. This study prospectively included 35 patients with cervical cancer who underwent pretreatment {sup 18}F-FDG PET/MR imaging. {sup 18}F-FDG PET and MR images were fused using standard software. The percent of the maximum standardized uptake values (SUV{sub max}) was used to contour tumours on PET images, and volumes were calculated automatically. Tumour volumes measured on T2-W and DW images were calculated with standard techniques of tumour area multiplied by the slice profile. Parametric statistics were used for data analysis. FDG PET tumour volumes calculated using SUV{sub max} (14.30 ± 4.70) and T2-W imaging volume (33.81 ± 27.32 cm{sup 3}) were similar (P > 0.05) at 35 % and 40 % of SUV{sub max} (32.91 ± 18.90 cm{sup 3} and 27.56 ± 17.19 cm{sup 3} respectively) and significantly correlated (P < 0.001; r = 0.735 and 0.766). The mean DW volume was 30.48 ± 22.41 cm{sup 3}. DW volumes were not significantly different from FDG PET volumes at either 35 % SUV{sub max} or 40 % SUV{sub max} or from T2-W imaging volumes (P > 0.05). PET subvolumes with increasing SUV{sub max} cut-off percentage showed an inverse change in mean ADC values on DW imaging (P < 0.001, ANOVA). Hybrid PET/MR showed strong volume concordance between FDG PET, and T2-W and DW imaging in cervical cancer. Cut-off at 35 % or 40 % of SUV{sub max} is recommended for {sup 18}F-FDG PET/MR SUV-based tumour volume estimation. The linear tumour subvolume concordance between FDG PET and DW imaging demonstrates individual regional concordance of metabolic activity and cell density. (orig.)

Estimation of free volumes of polystyrene by positron annihilation life-time technique

International Nuclear Information System (INIS)

Li, Hong-Ling; Ujihira, Yusuke; Nanasawa, Atsushi.

1996-01-01

Differences of size, content, and size distribution of free volumes in linear and three-armed polystyrenes, synthesized by radical, and anionic processes, were observed by positron annihilation lifetime measurements. For the polystyrene samples of different architectures and molecular weight distributions, the temperature dependence of an average free volume radius was quite similar to each other. The radius increased with increasing temperature (T), from 0.27 nm (60 K) to 0.30 nm (glass transition temperature: T g = 363 K), then to 0.35 nm (423 K), showing αβ transition temperature about 300 K. With increasing T, the free volume content decreased from 35% (60 K) to 25% (260 K) for radically polymerized linear polystyrene and to 22% (320 K) for anionically polymerized three-armed polystyrene, and then turned to increase to 35% at 350 K and 400 K, respectively. In contrast, the content for anionically polymerized linear polystyrene decreased from 45% (60 K) to 33% (300 K) and turned to increase to 35% at 350-400 K. The free volume content decreased reciprocally with an increase in the molecular weight at 333 K, suggesting differences in molecular motion between the edge and middle portions of the chain molecule. (author)

Weight and body mass index in relation to irradiated volume and to overall survival in patients with oropharyngeal cancer: a retrospective cohort study

International Nuclear Information System (INIS)

Ottosson, Sandra; Söderström, Karin; Kjellén, Elisabeth; Nilsson, Per; Zackrisson, Björn; Laurell, Göran

2014-01-01

Weight loss is a common problem in patients with Squamous Cell Carcinoma of the Head and Neck (SCCHN) treated with radiotherapy (RT). The aims of the present study were to determine if treated volume (TV), as a measure of the radiation dose burden, can predict weight loss in patients with oropharyngeal cancer and to analyze weight loss and body mass index (BMI) in the same patient group in relation to 5-year overall survival. The ARTSCAN trial is a prospective, randomized, multicenter trial in patients with SCCHN. Nutritional data from the ARTSCAN trial were analyzed retrospectively using univariate and multivariate statistical methods based on information on percentage weight loss from the start of RT up to five months after the termination of RT (study cohort 1, n = 232) and information on patients’ BMI at the start of RT (study cohort 2, n = 203). TV was defined as the volume of the patient receiving at least 95% of the prescribed dose. TV 64.6Gy encompasses macroscopic tumor and TV 43.7Gy elective lymph nodes of the neck. TV 64.6Gy and TV 43.7Gy were both significantly correlated with higher weight loss up to five months after the termination of RT in study cohort 1 (p < 0.001 for both). BMI at the start of RT was shown to be a prognostic factor for 5-year overall survival in study cohort 2 but weight loss was not. The hazard ratios and 95% confidence intervals were 3.78 (1.46–9.75) and 2.57 (1.43–4.62) in patients with underweight and normal weight, respectively. TV can predict weight loss during RT in patients with oropharyngeal cancer regardless of clinical stage. A high BMI (>25 kg/m 2 ) at the start of RT is positively associated with survival in patients with oropharyngeal cancer

Regional averaging and scaling in relativistic cosmology

International Nuclear Information System (INIS)

Buchert, Thomas; Carfora, Mauro

2002-01-01

Averaged inhomogeneous cosmologies lie at the forefront of interest, since cosmological parameters such as the rate of expansion or the mass density are to be considered as volume-averaged quantities and only these can be compared with observations. For this reason the relevant parameters are intrinsically scale-dependent and one wishes to control this dependence without restricting the cosmological model by unphysical assumptions. In the latter respect we contrast our way to approach the averaging problem in relativistic cosmology with shortcomings of averaged Newtonian models. Explicitly, we investigate the scale-dependence of Eulerian volume averages of scalar functions on Riemannian three-manifolds. We propose a complementary view of a Lagrangian smoothing of (tensorial) variables as opposed to their Eulerian averaging on spatial domains. This programme is realized with the help of a global Ricci deformation flow for the metric. We explain rigorously the origin of the Ricci flow which, on heuristic grounds, has already been suggested as a possible candidate for smoothing the initial dataset for cosmological spacetimes. The smoothing of geometry implies a renormalization of averaged spatial variables. We discuss the results in terms of effective cosmological parameters that would be assigned to the smoothed cosmological spacetime. In particular, we find that on the smoothed spatial domain B-bar evaluated cosmological parameters obey Ω-bar B-bar m + Ω-bar B-bar R + Ω-bar B-bar A + Ω-bar B-bar Q 1, where Ω-bar B-bar m , Ω-bar B-bar R and Ω-bar B-bar A correspond to the standard Friedmannian parameters, while Ω-bar B-bar Q is a remnant of cosmic variance of expansion and shear fluctuations on the averaging domain. All these parameters are 'dressed' after smoothing out the geometrical fluctuations, and we give the relations of the 'dressed' to the 'bare' parameters. While the former provide the framework of interpreting observations with a 'Friedmannian bias

Longitudinal study of hippocampal volumes in heavy cannabis users.

Science.gov (United States)

Koenders, L; Lorenzetti, V; de Haan, L; Suo, C; Vingerhoets, Wam; van den Brink, W; Wiers, R W; Meijer, C J; Machielsen, Mwj; Goudriaan, A E; Veltman, D J; Yücel, M; Cousijn, J

2017-08-01

Cannabis exposure, particularly heavy cannabis use, has been associated with neuroanatomical alterations in regions rich with cannabinoid receptors such as the hippocampus in some but not in other (mainly cross-sectional) studies. However, it remains unclear whether continued heavy cannabis use alters hippocampal volume, and whether an earlier age of onset and/or a higher dosage exacerbate these changes. Twenty heavy cannabis users (mean age 21 years, range 18-24 years) and 23 matched non-cannabis using healthy controls were submitted to a comprehensive psychological assessment and magnetic resonance imaging scan at baseline and at follow-up (average of 39 months post-baseline; standard deviation=2.4). Cannabis users started smoking around 16 years and smoked on average five days per week. A novel aspect of the current study is that hippocampal volume estimates were obtained from manual tracing the hippocampus on T1-weighted anatomical magnetic resonance imaging scans, using a previously validated protocol. Compared to controls, cannabis users did not show hippocampal volume alterations at either baseline or follow-up. Hippocampal volumes increased over time in both cannabis users and controls, following similar trajectories of increase. Cannabis dose and age of onset of cannabis use did not affect hippocampal volumes. Continued heavy cannabis use did not affect hippocampal neuroanatomical changes in early adulthood. This contrasts with prior evidence on alterations in this region in samples of older adult cannabis users. In young adults using cannabis at this level, cannabis use may not be heavy enough to affect hippocampal neuroanatomy.

A practical guide to averaging functions

CERN Document Server

Beliakov, Gleb; Calvo Sánchez, Tomasa

2016-01-01

This book offers an easy-to-use and practice-oriented reference guide to mathematical averages. It presents different ways of aggregating input values given on a numerical scale, and of choosing and/or constructing aggregating functions for specific applications. Building on a previous monograph by Beliakov et al. published by Springer in 2007, it outlines new aggregation methods developed in the interim, with a special focus on the topic of averaging aggregation functions. It examines recent advances in the field, such as aggregation on lattices, penalty-based aggregation and weakly monotone averaging, and extends many of the already existing methods, such as: ordered weighted averaging (OWA), fuzzy integrals and mixture functions. A substantial mathematical background is not called for, as all the relevant mathematical notions are explained here and reported on together with a wealth of graphical illustrations of distinct families of aggregation functions. The authors mainly focus on practical applications ...

RESEARCH ON WEIGHT EVOLUTION AND DAILY AVERAGE INCREASE TO FOUR DIFFERENT GROUPS OF LITTLE CROSSBREED BULLS EXPOSED TO INTENSIVE FATTENING

Directory of Open Access Journals (Sweden)

I.R. MOLDOVAN

2009-10-01

Full Text Available Research aimed to highlight the weight differences and daily growth average of four groups of little crossbreed bulls raised in the same environmental conditions and having the same feeding diet. Farm in which they do research is TCE 3 abis SRL Piatra Neamt, located in Zanesti village at 14 km from the city of Piatra Neamt. Location of the farm is on the old IAS Zanesti and is endowed eight shelters from which two are still functional. Shelters are divided into collective lumber rooms, on which are housed an optimal number of calves depending on their age, number varied from 25 calves at 0 - 3 months up to 6 heads during growing and finishing period when they reach weights of 600-700 kg. Farm population is obtained with calves from reformed cows from milk farm belonging to the same company. Forage base is provided from the company's vegetable farm, farm exploits about 14,000 ha of arable land in Neamt County. Feeding (in three phases is made with the technological trailer once-daily in morning and drinking is made at discretion at constant.

MRI to delineate the gross tumor volume of nasopharyngeal cancers: which sequences and planes should be used?

Science.gov (United States)

Popovtzer, Aron; Ibrahim, Mohannad; Tatro, Daniel; Feng, Felix Y; Ten Haken, Randall K; Eisbruch, Avraham

2014-09-01

Magnetic resonance imaging (MRI) has been found to be better than computed tomography for defining the extent of primary gross tumor volume (GTV) in advanced nasopharyngeal cancer. It is routinely applied for target delineation in planning radiotherapy. However, the specific MRI sequences/planes that should be used are unknown. Twelve patients with nasopharyngeal cancer underwent primary GTV evaluation with gadolinium-enhanced axial T1 weighted image (T1) and T2 weighted image (T2), coronal T1, and sagittal T1 sequences. Each sequence was registered with the planning computed tomography scans. Planning target volumes (PTVs) were derived by uniform expansions of the GTVs. The volumes encompassed by the various sequences/planes, and the volumes common to all sequences/planes, were compared quantitatively and anatomically to the volume delineated by the commonly used axial T1-based dataset. Addition of the axial T2 sequence increased the axial T1-based GTV by 12% on average (p = 0.004), and composite evaluations that included the coronal T1 and sagittal T1 planes increased the axial T1-based GTVs by 30% on average (p = 0.003). The axial T1-based PTVs were increased by 20% by the additional sequences (p = 0.04). Each sequence/plane added unique volume extensions. The GTVs common to all the T1 planes accounted for 38% of the total volumes of all the T1 planes. Anatomically, addition of the coronal and sagittal-based GTVs extended the axial T1-based GTV caudally and cranially, notably to the base of the skull. Adding MRI planes and sequences to the traditional axial T1 sequence yields significant quantitative and anatomically important extensions of the GTVs and PTVs. For accurate target delineation in nasopharyngeal cancer, we recommend that GTVs be outlined in all MRI sequences/planes and registered with the planning computed tomography scans.

The flattening of the average potential in models with fermions

International Nuclear Information System (INIS)

Bornholdt, S.

1993-01-01

The average potential is a scale dependent scalar effective potential. In a phase with spontaneous symmetry breaking its inner region becomes flat as the averaging extends over infinite volume and the average potential approaches the convex effective potential. Fermion fluctuations affect the shape of the average potential in this region and its flattening with decreasing physical scale. They have to be taken into account to find the true minimum of the scalar potential which determines the scale of spontaneous symmetry breaking. (orig.)

Averages, Areas and Volumes; Cambridge Conference on School Mathematics Feasibility Study No. 45.

Science.gov (United States)

Cambridge Conference on School Mathematics, Newton, MA.

Presented is an elementary approach to areas, columns and other mathematical concepts usually treated in calculus. The approach is based on the idea of average and this concept is utilized throughout the report. In the beginning the average (arithmetic mean) of a set of numbers is considered and two properties of the average which often simplify…

Perfluoroalkyl substances and changes in body weight and resting metabolic rate in response to weight-loss diets

DEFF Research Database (Denmark)

Liu, Gang; Dhana, Klodian; Furtado, Jeremy D

2018-01-01

in body weight and resting metabolic rate (RMR) in a diet-induced weight-loss setting. METHODS AND FINDINGS: In the 2-year POUNDS Lost randomized clinical trial based in Boston, Massachusetts, and Baton Rouge, Louisiana, that examined the effects of energy-restricted diets on weight changes, baseline...... and 24 months. Participants lost an average of 6.4 kg of body weight during the first 6 months (weight-loss period) and subsequently regained an average of 2.7 kg of body weight during the period of 6-24 months (weight regain period). After multivariate adjustment, baseline PFAS concentrations were...... not significantly associated with concurrent body weight or weight loss during the first 6 months. In contrast, higher baseline levels of PFASs were significantly associated with a greater weight regain, primarily in women. In women, comparing the highest to the lowest tertiles of PFAS concentrations...

High initial tidal volumes in emergency department patients at risk for acute respiratory distress syndrome.

Science.gov (United States)

Allison, Michael G; Scott, Michael C; Hu, Kami M; Witting, Michael D; Winters, Michael E

2015-04-01

Emergency department (ED) patients are at high risk for the acute respiratory distress syndrome (ARDS). Settings only 1 mL/kg above recommended tidal volumes confers harm for these patients. The purpose of this study was to determine whether ED physicians routinely initiate mechanical ventilation with low tidal volumes in patients at risk for ARDS. We retrospectively reviewed the charts of all adult patients who were intubated in an urban, academic ED. The charts were analyzed to identify patients in whom ARDS developed within 48 hours after ED admission. Patients were eligible for inclusion if they had bilateral infiltrates on imaging, had a Pao2/Fio2 ratio less than 300 mm Hg and did not have heart failure contributing to their presentation. The tidal volumes set in the ED were then compared with the recommended tidal volume of 6 mL/kg of predicted body weight. The initial tidal volumes set in the ED were higher than recommended by an average of 80 mL (95% confidence interval, 60-110, P tidal volume ventilation setting. In an academic, tertiary hospital, newly intubated ED patients in whom ARDS developed within 48 hours after intubation were ventilated with tidal volumes that exceeded recommendations by an average of 1.5 mL/kg. Copyright © 2014 Elsevier Inc. All rights reserved.

Intralesional and metastatic heterogeneity in malignant melanomas demonstrated by stereologic estimates of nuclear volume

DEFF Research Database (Denmark)

Sørensen, Flemming Brandt; Erlandsen, M

1990-01-01

Regional variability of nuclear 3-dimensional size can be estimated objectively using point-sampled intercepts obtained from different, defined zones within individual neoplasms. In the present study, stereologic estimates of the volume-weighted mean nuclear volume, nuclear vv, within peripheral...... on average larger in the peripheral zones of primary melanomas, than nuclear vv in central zones (2p = 6.7 x 10(-4), whereas no zonal differences were demonstrated in metastatic lesions (2p = 0.21). A marked intraindividual variation was demonstrated between primary and corresponding secondary melanomas (2p...... melanomas showed large interindividual variation. This finding emphasizes that unbiased estimates of nuclear vv are robust to regional heterogeneity of nuclear volume and thus suitable for purposes of objective, quantitative malignancy grading of melanomas....

How to average logarithmic retrievals?

Directory of Open Access Journals (Sweden)

B. Funke

2012-04-01

Full Text Available Calculation of mean trace gas contributions from profiles obtained by retrievals of the logarithm of the abundance rather than retrievals of the abundance itself are prone to biases. By means of a system simulator, biases of linear versus logarithmic averaging were evaluated for both maximum likelihood and maximum a priori retrievals, for various signal to noise ratios and atmospheric variabilities. These biases can easily reach ten percent or more. As a rule of thumb we found for maximum likelihood retrievals that linear averaging better represents the true mean value in cases of large local natural variability and high signal to noise ratios, while for small local natural variability logarithmic averaging often is superior. In the case of maximum a posteriori retrievals, the mean is dominated by the a priori information used in the retrievals and the method of averaging is of minor concern. For larger natural variabilities, the appropriateness of the one or the other method of averaging depends on the particular case because the various biasing mechanisms partly compensate in an unpredictable manner. This complication arises mainly because of the fact that in logarithmic retrievals the weight of the prior information depends on abundance of the gas itself. No simple rule was found on which kind of averaging is superior, and instead of suggesting simple recipes we cannot do much more than to create awareness of the traps related with averaging of mixing ratios obtained from logarithmic retrievals.

Fitting a function to time-dependent ensemble averaged data

DEFF Research Database (Denmark)

Fogelmark, Karl; Lomholt, Michael A.; Irbäck, Anders

2018-01-01

Time-dependent ensemble averages, i.e., trajectory-based averages of some observable, are of importance in many fields of science. A crucial objective when interpreting such data is to fit these averages (for instance, squared displacements) with a function and extract parameters (such as diffusion...... method, weighted least squares including correlation in error estimation (WLS-ICE), to particle tracking data. The WLS-ICE method is applicable to arbitrary fit functions, and we provide a publically available WLS-ICE software....

Essays on model averaging and political economics

NARCIS (Netherlands)

Wang, W.

2013-01-01

This thesis first investigates various issues related with model averaging, and then evaluates two policies, i.e. West Development Drive in China and fiscal decentralization in U.S, using econometric tools. Chapter 2 proposes a hierarchical weighted least squares (HWALS) method to address multiple

Physics-preserving averaging scheme based on Grunwald-Letnikov formula for gas flow in fractured media

KAUST Repository

Amir, Sahar Z.

2018-01-02

The heterogeneous natures of rock fabrics, due to the existence of multi-scale fractures and geological formations, led to the deviations from unity in the flux-equations fractional-exponent magnitudes. In this paper, the resulting non-Newtonian non-Darcy fractional-derivatives flux equations are solved using physics-preserving averaging schemes that incorporates both, original and shifted, Grunwald-Letnikov (GL) approximation formulas preserving the physics, by reducing the shifting effects, while maintaining the stability of the system, by keeping one shifted expansion. The proposed way of using the GL expansions also generate symmetrical coefficient matrices that significantly reduces the discretization complexities appearing with all shifted cases from literature, and help considerably in 2D and 3D systems. Systems equations derivations and discretization details are discussed. Then, the physics-preserving averaging scheme is explained and illustrated. Finally, results are presented and reviewed. Edge-based original GL expansions are unstable as also illustrated in literatures. Shifted GL expansions are stable but add a lot of additional weights to both discretization sides affecting the physical accuracy. In comparison, the physics-preserving averaging scheme balances the physical accuracy and stability requirements leading to a more physically conservative scheme that is more stable than the original GL approximation but might be slightly less stable than the shifted GL approximations. It is a locally conservative Single-Continuum averaging scheme that applies a finite-volume viewpoint.

Physics-preserving averaging scheme based on Grunwald-Letnikov formula for gas flow in fractured media

KAUST Repository

Amir, Sahar Z.; Sun, Shuyu

2018-01-01

The heterogeneous natures of rock fabrics, due to the existence of multi-scale fractures and geological formations, led to the deviations from unity in the flux-equations fractional-exponent magnitudes. In this paper, the resulting non-Newtonian non-Darcy fractional-derivatives flux equations are solved using physics-preserving averaging schemes that incorporates both, original and shifted, Grunwald-Letnikov (GL) approximation formulas preserving the physics, by reducing the shifting effects, while maintaining the stability of the system, by keeping one shifted expansion. The proposed way of using the GL expansions also generate symmetrical coefficient matrices that significantly reduces the discretization complexities appearing with all shifted cases from literature, and help considerably in 2D and 3D systems. Systems equations derivations and discretization details are discussed. Then, the physics-preserving averaging scheme is explained and illustrated. Finally, results are presented and reviewed. Edge-based original GL expansions are unstable as also illustrated in literatures. Shifted GL expansions are stable but add a lot of additional weights to both discretization sides affecting the physical accuracy. In comparison, the physics-preserving averaging scheme balances the physical accuracy and stability requirements leading to a more physically conservative scheme that is more stable than the original GL approximation but might be slightly less stable than the shifted GL approximations. It is a locally conservative Single-Continuum averaging scheme that applies a finite-volume viewpoint.

Averaging in spherically symmetric cosmology

International Nuclear Information System (INIS)

Coley, A. A.; Pelavas, N.

2007-01-01

The averaging problem in cosmology is of fundamental importance. When applied to study cosmological evolution, the theory of macroscopic gravity (MG) can be regarded as a long-distance modification of general relativity. In the MG approach to the averaging problem in cosmology, the Einstein field equations on cosmological scales are modified by appropriate gravitational correlation terms. We study the averaging problem within the class of spherically symmetric cosmological models. That is, we shall take the microscopic equations and effect the averaging procedure to determine the precise form of the correlation tensor in this case. In particular, by working in volume-preserving coordinates, we calculate the form of the correlation tensor under some reasonable assumptions on the form for the inhomogeneous gravitational field and matter distribution. We find that the correlation tensor in a Friedmann-Lemaitre-Robertson-Walker (FLRW) background must be of the form of a spatial curvature. Inhomogeneities and spatial averaging, through this spatial curvature correction term, can have a very significant dynamical effect on the dynamics of the Universe and cosmological observations; in particular, we discuss whether spatial averaging might lead to a more conservative explanation of the observed acceleration of the Universe (without the introduction of exotic dark matter fields). We also find that the correlation tensor for a non-FLRW background can be interpreted as the sum of a spatial curvature and an anisotropic fluid. This may lead to interesting effects of averaging on astrophysical scales. We also discuss the results of averaging an inhomogeneous Lemaitre-Tolman-Bondi solution as well as calculations of linear perturbations (that is, the backreaction) in an FLRW background, which support the main conclusions of the analysis

When good = better than average

Directory of Open Access Journals (Sweden)

Don A. Moore

2007-10-01

Full Text Available People report themselves to be above average on simple tasks and below average on difficult tasks. This paper proposes an explanation for this effect that is simpler than prior explanations. The new explanation is that people conflate relative with absolute evaluation, especially on subjective measures. The paper then presents a series of four studies that test this conflation explanation. These tests distinguish conflation from other explanations, such as differential weighting and selecting the wrong referent. The results suggest that conflation occurs at the response stage during which people attempt to disambiguate subjective response scales in order to choose an answer. This is because conflation has little effect on objective measures, which would be equally affected if the conflation occurred at encoding.

Fitting a function to time-dependent ensemble averaged data.

Science.gov (United States)

Fogelmark, Karl; Lomholt, Michael A; Irbäck, Anders; Ambjörnsson, Tobias

2018-05-03

Time-dependent ensemble averages, i.e., trajectory-based averages of some observable, are of importance in many fields of science. A crucial objective when interpreting such data is to fit these averages (for instance, squared displacements) with a function and extract parameters (such as diffusion constants). A commonly overlooked challenge in such function fitting procedures is that fluctuations around mean values, by construction, exhibit temporal correlations. We show that the only available general purpose function fitting methods, correlated chi-square method and the weighted least squares method (which neglects correlation), fail at either robust parameter estimation or accurate error estimation. We remedy this by deriving a new closed-form error estimation formula for weighted least square fitting. The new formula uses the full covariance matrix, i.e., rigorously includes temporal correlations, but is free of the robustness issues, inherent to the correlated chi-square method. We demonstrate its accuracy in four examples of importance in many fields: Brownian motion, damped harmonic oscillation, fractional Brownian motion and continuous time random walks. We also successfully apply our method, weighted least squares including correlation in error estimation (WLS-ICE), to particle tracking data. The WLS-ICE method is applicable to arbitrary fit functions, and we provide a publically available WLS-ICE software.

PREOPERATIVE COMPUTED TOMOGRAPHY VOLUMETRY AND GRAFT WEIGHT ESTIMATION IN ADULT LIVING DONOR LIVER TRANSPLANTATION.

Science.gov (United States)

Pinheiro, Rafael S; Cruz, Ruy J; Andraus, Wellington; Ducatti, Liliana; Martino, Rodrigo B; Nacif, Lucas S; Rocha-Santos, Vinicius; Arantes, Rubens M; Lai, Quirino; Ibuki, Felicia S; Rocha, Manoel S; D Albuquerque, Luiz A C

2017-01-01

Computed tomography volumetry (CTV) is a useful tool for predicting graft weights (GW) for living donor liver transplantation (LDLT). Few studies have examined the correlation between CTV and GW in normal liver parenchyma. To analyze the correlation between CTV and GW in an adult LDLT population and provide a systematic review of the existing mathematical models to calculate partial liver graft weight. Between January 2009 and January 2013, 28 consecutive donors undergoing right hepatectomy for LDLT were retrospectively reviewed. All grafts were perfused with HTK solution. Estimated graft volume was estimated by CTV and these values were compared to the actual graft weight, which was measured after liver harvesting and perfusion. Median actual GW was 782.5 g, averaged 791.43±136 g and ranged from 520-1185 g. Median estimated graft volume was 927.5 ml, averaged 944.86±200.74 ml and ranged from 600-1477 ml. Linear regression of estimated graft volume and actual GW was significantly linear (GW=0.82 estimated graft volume, r2=0.98, slope=0.47, standard deviation of 0.024 and ppeso do enxerto (PE) para o transplante hepático com doador vivo (TFDV). Poucos estudos examinaram a correlação entre o VTC e PE no parênquima hepático normal. Analisar a correlação entre VTC e PE em uma população adulta de doadores para o TFDV e realização de revisão sistemática dos modelos matemáticos existentes para calcular o peso de enxertos hepáticos parciais. Foram revisados retrospectivamente 28 doadores consecutivos submetidos à hepatectomia direita para o TFDV entre janeiro de 2009 a janeiro de 2013. Todos os doadores eram adultos saudáveis ​​com VTC pré-operatório. Os enxertos foram perfundidos com solução de preservação HTK. O volume estimado foi obtido por VTC e estes valores foram comparados com o peso real do enxerto, o qual foi aferido depois da hepatectomia e perfusão do enxerto. A mediana do PE real foi de 782,5 g, média de 791,43±136 g, variando

Birth weight and perinatal mortality: A comparison of "optimal" birth weight in seven western European countries

NARCIS (Netherlands)

Graafmans, W.C.; Richardus, J.H.; Borsboom, G.J.J.M.; Bakketeig, L.; Langhoff-Roos, J.; Bergsjø, P.; Macfarlane, A.; Verloove-Vanhorick, P.; Mackenbach, J.; Aelvoet, W.; Alderdice, F.; Amelink, M.; Bakoula, C.; Blondel, B.; Bødker, B.; Bolumar, F.; Davidson, L.; Gissler, M.; Hartikainen, A.L.; Holt, J.; Kaminski, M.; Leidinger, J.; Lekea, V.; Lindmark, G.; Masuy-Stroobant, G.; Pal, K. van der; Penney, G.; Purificação Araújo, M. Da; Rantakallio, P.; Rebagliato, M.

2002-01-01

Background. Previous studies have suggested that a population's entire birth weight distribution may be shifted towards higher or lower birth weights, and that optimal birth weight may be lower in populations with a lower average birth weight. We evaluated this hypothesis for seven western European

Genome-Enabled Prediction of Breeding Values for Feedlot Average Daily Weight Gain in Nelore Cattle

Directory of Open Access Journals (Sweden)

Adriana L. Somavilla

2017-06-01

Full Text Available Nelore is the most economically important cattle breed in Brazil, and the use of genetically improved animals has contributed to increased beef production efficiency. The Brazilian beef feedlot industry has grown considerably in the last decade, so the selection of animals with higher growth rates on feedlot has become quite important. Genomic selection (GS could be used to reduce generation intervals and improve the rate of genetic gains. The aim of this study was to evaluate the prediction of genomic-estimated breeding values (GEBV for average daily weight gain (ADG in 718 feedlot-finished Nelore steers. Analyses of three Bayesian model specifications [Bayesian GBLUP (BGBLUP, BayesA, and BayesCπ] were performed with four genotype panels [Illumina BovineHD BeadChip, TagSNPs, and GeneSeek High- and Low-density indicus (HDi and LDi, respectively]. Estimates of Pearson correlations, regression coefficients, and mean squared errors were used to assess accuracy and bias of predictions. Overall, the BayesCπ model resulted in less biased predictions. Accuracies ranged from 0.18 to 0.27, which are reasonable values given the heritability estimates (from 0.40 to 0.44 and sample size (568 animals in the training population. Furthermore, results from Bos taurus indicus panels were as informative as those from Illumina BovineHD, indicating that they could be used to implement GS at lower costs.

Relationship between Contrast Enhancement of the Perivascular Space in the Basal Ganglia and Endolymphatic Volume Ratio.

Science.gov (United States)

Ohashi, Toshio; Naganawa, Shinji; Katagiri, Toshio; Kuno, Kayao

2018-01-10

We routinely obtain the endolymphatic hydrops (EH) image using heavily T 2 -weighted three dimensional-fluid attenuated inversion recovery (hT 2 w-3D-FLAIR) imaging at 4 hours after intravenous administration of a single-dose of gadolinium-based contrast media (IV-SD-GBCM). While repeating the examination, we speculated that the contrast enhancement of the perivascular space (PVS) in the basal ganglia might be related to the degree of EH. Therefore, the purpose of this study was to investigate the relationship between the endolymphatic volume ratio (%EL volume ) and the signal intensity of the PVS (SI-PVS). In 20 patients with a suspicion of EH, a heavily T 2 -weighted 3D-turbo spin echo sequence for MR cisternography (MRC) and an hT 2 w-3D-FLAIR as a positive perilymph image (PPI) were obtained at 4 hours after IV-SD-GBCM. The %EL volume of the cochlea and the vestibule were measured on the previously reported HYDROPS2-Mi2 image. The PVS in the basal ganglia was segmented on MRC using a region-growing method. The PVS regions were copied and pasted onto the PPI, and the SI-PVS was measured. The larger value of the right and the left ears was employed as the %EL volume , and the weighted average of both sides was employed as the SI-PVS. The correlation between the %EL volume and the SI-PVS was evaluated. There was a strong negative linear correlation between the %EL volume of the cochlea and the SI-PVS (r = -0.743, P < 0.001); however, there was no significant correlation between the %EL volume of the vestibule and the SI-PVS (r = -0.267, P = 0.256). There was a strong negative correlation between the cochlear %EL volume and the SI-PVS. Contrast enhancement of PVS might be a biomarker of EH.

Stereological estimates of nuclear volume in squamous cell carcinoma of the uterine cervix and its precursors

DEFF Research Database (Denmark)

Sørensen, Flemming Brandt; Bichel, P; Jakobsen, A

1991-01-01

Using modern stereology, this study was carried out to obtain base-line data concerning three-dimensional, mean nuclear size in precancerous and invasive lesions of the uterine cervix. Unbiased estimates of the volume-weighted mean nuclear volume (nuclear vv) were obtained by point-sampling of nu......Using modern stereology, this study was carried out to obtain base-line data concerning three-dimensional, mean nuclear size in precancerous and invasive lesions of the uterine cervix. Unbiased estimates of the volume-weighted mean nuclear volume (nuclear vv) were obtained by point......-sampling of nuclear intercepts in 51 pre-treatment biopsies from patients with invasive squamous cell carcinomas (SCC). Vertical sections from 27 specimens with cervical intraepithelial neoplasia (CIN) grades I through III were also investigated, along with 10 CIN III associated with microinvasion (CIN III + M......). On average, nuclear vv was larger in SCC than in CIN III and CIN III + M together (2 P = 8.9 . 10(-5). A conspicuous overlap of nuclear vv existed between all investigated lesional groups. The reproducibility of estimates of nuclear vv in biopsies with SCC was acceptable (r = 0.85 and r = 0.84 in intra...

Gd-DTPA and volume acquisitions in brain and spine tumors

International Nuclear Information System (INIS)

Ross, J.S.; Masaryk, T.J.; Modic, M.T.; Clampitt, M.

1988-01-01

Seventeen cases referred for evaluation of suspected neoplasms were studied with anisotropic three-dimensional fast low-angle shot imaging (30-60/9-14/50) with partitions of 1.5-3 mm before and after 0.1 mmol/kg of Gd-DTPA (Berlex Laboratories). Multiplanar reconstructions were performed on a Kontron work station. Sagittal and axial T1-weighted two-dimensional spin-echo (SE) sequences were acquired for comparison. Diagnoses included normal (N = 3), brain neoplasms (N = 7), spine neoplasms (N = 6), and brain inflammation (N = 1). Volume studies were of sufficient quality to allow reconstructions in 12 cases and were comparable diagnostically with two-dimensional SE images. Advantages of the three-dimensional technique were capacity to reconstruct any plane, decreased partial volume averaging, and a shorter examination time. Tissue contrast appeared equivalent. In five patients the examinations were inferior to SE studies because of motion and lack of contrast between vessels and enhancing regions. Paramagnetic contrast increases the sensitivity of volume studies in the detection of disease

Modified parity space averaging approaches for online cross-calibration of redundant sensors in nuclear reactors

Directory of Open Access Journals (Sweden)

Moath Kassim

2018-05-01

Full Text Available To maintain safety and reliability of reactors, redundant sensors are usually used to measure critical variables and estimate their averaged time-dependency. Nonhealthy sensors can badly influence the estimation result of the process variable. Since online condition monitoring was introduced, the online cross-calibration method has been widely used to detect any anomaly of sensor readings among the redundant group. The cross-calibration method has four main averaging techniques: simple averaging, band averaging, weighted averaging, and parity space averaging (PSA. PSA is used to weigh redundant signals based on their error bounds and their band consistency. Using the consistency weighting factor (C, PSA assigns more weight to consistent signals that have shared bands, based on how many bands they share, and gives inconsistent signals of very low weight. In this article, three approaches are introduced for improving the PSA technique: the first is to add another consistency factor, so called trend consistency (TC, to include a consideration of the preserving of any characteristic edge that reflects the behavior of equipment/component measured by the process parameter; the second approach proposes replacing the error bound/accuracy based weighting factor (Wa with a weighting factor based on the Euclidean distance (Wd, and the third approach proposes applying Wd,TC,andC, all together. Cold neutron source data sets of four redundant hydrogen pressure transmitters from a research reactor were used to perform the validation and verification. Results showed that the second and third modified approaches lead to reasonable improvement of the PSA technique. All approaches implemented in this study were similar in that they have the capability to (1 identify and isolate a drifted sensor that should undergo calibration, (2 identify a faulty sensor/s due to long and continuous missing data range, and (3 identify a healthy sensor. Keywords: Nuclear Reactors

General expressions for the volume of organs in the MIRD-phantom and their use to arrive at an Indian ''reference'' man

International Nuclear Information System (INIS)

Shiv Datta

1982-01-01

The general expressions for the volume of body organs have been developed, when their equations are assumed to be of the same form as in the MIRD phantom. Scaling down is then carried out by introducing factors based on the average weight and height of a group of Indian adult males (workers in various units of Department of Atomic Energy, India). The general expressions for the volume of the body organs will be found handy to use when the actual data of the organs (ratios of the lengths of their axes and the volumes) become available. (author)

Liver volume, intrahepatic fat and body weight in the course of a lifestyle interventional study. Analysis with quantitative MR-based methods; Lebervolumen, Leberfettanteil und Koerpergewicht im Verlauf einer Lebensstilinterventionsstudie. Eine Analyse mit quantitativen MR-basierten Methoden

Energy Technology Data Exchange (ETDEWEB)

Bongers, M.N. [Klinikum der Eberhard-Karls-Universitaet Tuebingen, Abteilung fuer Diagnostische und Interventionelle Radiologie, Tuebingen (Germany); Universitaetsklinikum Tuebingen, Sektion fuer Experimentelle Radiologie der Abteilung fuer Diagnostische und Interventionelle Radiologie, Tuebingen (Germany); Stefan, N.; Fritsche, A.; Haering, H.U. [Universitaetsklinikum Tuebingen, Innere Medizin IV - Endokrinologie und Diabetologie, Angiologie, Nephrologie und Klinische Chemie, Tuebingen (Germany); Helmholtz-Zentrum Muenchen an der Universitaet Tuebingen, Institut fuer Diabetes-Forschung und Metabolische Erkrankungen (IDM), Tuebingen (Germany); Nikolaou, K. [Klinikum der Eberhard-Karls-Universitaet Tuebingen, Abteilung fuer Diagnostische und Interventionelle Radiologie, Tuebingen (Germany); Schick, F. [Universitaetsklinikum Tuebingen, Sektion fuer Experimentelle Radiologie der Abteilung fuer Diagnostische und Interventionelle Radiologie, Tuebingen (Germany); Machann, J. [Universitaetsklinikum Tuebingen, Sektion fuer Experimentelle Radiologie der Abteilung fuer Diagnostische und Interventionelle Radiologie, Tuebingen (Germany); Helmholtz-Zentrum Muenchen an der Universitaet Tuebingen, Institut fuer Diabetes-Forschung und Metabolische Erkrankungen (IDM), Tuebingen (Germany); Deutsches Zentrum fuer Diabetesforschung (DZD), Neuherberg (Germany)

2015-04-01

The aim of this study was to investigate potential associations between changes in liver volume, the amount of intrahepatic lipids (IHL) and body weight during lifestyle interventions. In a prospective study 150 patients with an increased risk for developing type 2 diabetes mellitus were included who followed a caloric restriction diet for 6 months. In the retrospective analysis 18 women and 9 men (age range 22-71 years) with an average body mass index (BMI) of 32 kg/m{sup 2} were enrolled. The liver volume was determined at the beginning and after 6 months by three-dimensional magnetic resonance imaging (3D-MRI, echo gradient, opposed-phase) and IHLs were quantified by volume-selective MR spectroscopy in single voxel stimulated echo acquisition mode (STEAM). Univariable and multivariable correlation analyses between changes of liver volume (Δliver volume), intrahepatic lipids (ΔIHL) and body weight (ΔBW) were performed. Univariable correlation analysis in the whole study cohort showed associations between ΔIHL and ΔBW (r = 0.69; p < 0.0001), ΔIHL and Δliver volume (r = 0.66; p = 0.0002) as well as ΔBW and Δliver volume (r = 0.5; p = 0.0073). Multivariable correlation analysis revealed that changes of liver volume are primarily determined by changes in IHL independent of changes in body weight (β = 0.0272; 95 % CI: 0.0155-0.034; p < 0.0001). Changes of liver volume during lifestyle interventions are independent of changes of body weight primarily determined by changes of IHL. These results show the reversibility of augmented liver volume in steatosis if it is possible to reduce IHLs during lifestyle interventions. (orig.) [German] Lassen sich Zusammenhaenge zwischen den Aenderungen des Lebervolumens, des Anteils intrahepatischer Lipide und des Koerpergewichts waehrend einer Lebensstilintervention feststellen ?In einer prospektiven Interventionsstudie unterzogen sich 150 Probanden mit erhoehtem Diabetesrisiko fuer 6 Monate einer diaetetischen

Can Beta Blockers Cause Weight Gain?

Science.gov (United States)

... cause weight gain? Can beta blockers cause weight gain? Answers from Sheldon G. Sheps, M.D. Yes. Weight gain can occur as a side effect of some ... and metoprolol (Lopressor, Toprol-XL). The average weight gain is about 2.6 pounds (about 1.2 ...

Long-term, low-level radwaste volume-reduction strategies. Volume 4. Waste disposal costs. Final report

International Nuclear Information System (INIS)

Sutherland, A.A.; Adam, J.A.; Rogers, V.C.; Merrell, G.B.

1984-11-01

Volume 4 establishes pricing levels at new shallow land burial grounds. The following conclusions can be drawn from the analyses described in the preceding chapters: Application of volume reduction techniques by utilities can have a significant impact on the volumes of wastes going to low-level radioactive waste disposal sites. Using the relative waste stream volumes in NRC81 and the maximum volume reduction ratios provided by Burns and Roe, Inc., it was calculated that if all utilities use maximum volume reduction the rate of waste receipt at disposal sites will be reduced by 40 percent. When a disposal site receives a lower volume of waste its total cost of operation does not decrease by the same proportion. Therefore the average cost for a unit volume of waste received goes up. Whether the disposal site operator knows in advance that he will receive a smaller amount of waste has little influence on the average unit cost ($/ft) of the waste disposed. For the pricing algorithm postulated, the average disposal cost to utilities that volume reduce is relatively independent of whether all utilities practice volume reduction or only a few volume reduce. The general effect of volume reduction by utilities is to reduce their average disposal site costs by a factor of between 1.5 to 2.5. This factor is generally independent of the size of the disposal site. The largest absolute savings in disposal site costs when utilities volume reduce occurs when small disposal sites are involved. This results from the fact that unit costs are higher at small sites. Including in the pricing algorithm a factor that penalizes waste generators who contribute larger amounts of the mobile nuclides 3 H, 14 C, 99 Tc, and 129 I, which may be the subject of site inventory limits, lowers unit disposal costs for utility wastes that contain only small amounts of the nuclides and raises unit costs for other utility wastes

Understanding the heterogeneity in volume overload and fluid distribution in decompensated heart failure is key to optimal volume management: role for blood volume quantitation.

Science.gov (United States)

Miller, Wayne L; Mullan, Brian P

2014-06-01

This study sought to quantitate total blood volume (TBV) in patients hospitalized for decompensated chronic heart failure (DCHF) and to determine the extent of volume overload, and the magnitude and distribution of blood volume and body water changes following diuretic therapy. The accurate assessment and management of volume overload in patients with DCHF remains problematic. TBV was measured by a radiolabeled-albumin dilution technique with intravascular volume, pre-to-post-diuretic therapy, evaluated at hospital admission and at discharge. Change in body weight in relation to quantitated TBV was used to determine interstitial volume contribution to total fluid loss. Twenty-six patients were prospectively evaluated. Two patients had normal TBV at admission. Twenty-four patients were hypervolemic with TBV (7.4 ± 1.6 liters) increased by +39 ± 22% (range, +9.5% to +107%) above the expected normal volume. With diuresis, TBV decreased marginally (+30 ± 16%). Body weight declined by 6.9 ± 5.2 kg, and fluid intake/fluid output was a net negative 8.4 ± 5.2 liters. Interstitial compartment fluid loss was calculated at 6.2 ± 4.0 liters, accounting for 85 ± 15% of the total fluid reduction. TBV analysis demonstrated a wide range in the extent of intravascular overload. Dismissal measurements revealed marginally reduced intravascular volume post-diuretic therapy despite large reductions in body weight. Mobilization of interstitial fluid to the intravascular compartment with diuresis accounted for this disparity. Intravascular volume, however, remained increased at dismissal. The extent, composition, and distribution of volume overload are highly variable in DCHF, and this variability needs to be taken into account in the approach to individualized therapy. TBV quantitation, particularly serial measurements, can facilitate informed volume management with respect to a goal of treating to euvolemia. Copyright © 2014 American College of Cardiology Foundation. Published

Correlation of ultrasound estimated placental volume and umbilical cord blood volume in term pregnancy.

Science.gov (United States)

Pannopnut, Papinwit; Kitporntheranunt, Maethaphan; Paritakul, Panwara; Kongsomboon, Kittipong

2015-01-01

To investigate the correlation between ultrasound measured placental volume and collected umbilical cord blood (UCB) volume in term pregnancy. An observational cross-sectional study of term singleton pregnant women in the labor ward at Maha Chakri Sirindhorn Medical Center was conducted. Placental thickness, height, and width were measured using two-dimensional (2D) ultrasound and calculated for placental volume using the volumetric mathematic model. After the delivery of the baby, UCB was collected and measured for its volume immediately. Then, birth weight, placental weight, and the actual placental volume were analyzed. The Pearson's correlation was used to determine the correlation between each two variables. A total of 35 pregnant women were eligible for the study. The mean and standard deviation of estimated placental volume and actual placental volume were 534±180 mL and 575±118 mL, respectively. The median UCB volume was 140 mL (range 98-220 mL). The UCB volume did not have a statistically significant correlation with the estimated placental volume (correlation coefficient 0.15; p=0.37). However, the UCB volume was significantly correlated with the actual placental volume (correlation coefficient 0.62; pcorrelation coefficient 0.38; p=0.02). The estimated placental volume by 2D ultrasound was not significantly correlated with the UCB volume. Further studies to establish the correlation between the UCB volume and the estimated placental volume using other types of placental imaging may be needed.

Gamut Volume Index: a color preference metric based on meta-analysis and optimized colour samples.

Science.gov (United States)

Liu, Qiang; Huang, Zheng; Xiao, Kaida; Pointer, Michael R; Westland, Stephen; Luo, M Ronnier

2017-07-10

A novel metric named Gamut Volume Index (GVI) is proposed for evaluating the colour preference of lighting. This metric is based on the absolute gamut volume of optimized colour samples. The optimal colour set of the proposed metric was obtained by optimizing the weighted average correlation between the metric predictions and the subjective ratings for 8 psychophysical studies. The performance of 20 typical colour metrics was also investigated, which included colour difference based metrics, gamut based metrics, memory based metrics as well as combined metrics. It was found that the proposed GVI outperformed the existing counterparts, especially for the conditions where correlated colour temperatures differed.

ORDERED WEIGHTED DISTANCE MEASURE

Institute of Scientific and Technical Information of China (English)

Zeshui XU; Jian CHEN

2008-01-01

The aim of this paper is to develop an ordered weighted distance (OWD) measure, which is thegeneralization of some widely used distance measures, including the normalized Hamming distance, the normalized Euclidean distance, the normalized geometric distance, the max distance, the median distance and the min distance, etc. Moreover, the ordered weighted averaging operator, the generalized ordered weighted aggregation operator, the ordered weighted geometric operator, the averaging operator, the geometric mean operator, the ordered weighted square root operator, the square root operator, the max operator, the median operator and the min operator axe also the special cases of the OWD measure. Some methods depending on the input arguments are given to determine the weights associated with the OWD measure. The prominent characteristic of the OWD measure is that it can relieve (or intensify) the influence of unduly large or unduly small deviations on the aggregation results by assigning them low (or high) weights. This desirable characteristic makes the OWD measure very suitable to be used in many actual fields, including group decision making, medical diagnosis, data mining, and pattern recognition, etc. Finally, based on the OWD measure, we develop a group decision making approach, and illustrate it with a numerical example.

[The ratio birth-weight, placental weight and the term of delivery. A contribution to the problem of a relative placental insufficiency in late pregnancy (author's transl)].

Science.gov (United States)

Warkentin, B

1976-12-10

It is suggested, that a relative placental insufficiency in late pregnancy is one of the releasing factors of childbirth. Under this assumption 1027 deliveries in term pregnancy (266th-294th day of pregnancy) were inquired on the interrelationship between the ratio brith-weight: placental-weight and the duration of pregnancy. The average birth-weight increases slighly but significantly with the duration of pregnancy just as the average placental-weight. The average ratio birth-weight: placental-weight decreases significantly: The more unfavorable the ratio birth-weight: placental-weight is, the shorter remains the fetus in utero. This underlines the assumption of a relative placental insufficiency as one of the releasing factors of childbirth.

Monitoring early response to anti-angiogenic therapy: diffusion-weighted magnetic resonance imaging and volume measurements in colon carcinoma xenografts.

Directory of Open Access Journals (Sweden)

Moritz Jörg Schneider

Full Text Available OBJECTIVES: To evaluate the use of diffusion-weighted MRI (DW-MRI and volume measurements for early monitoring of antiangiogenic therapy in an experimental tumor model. MATERIALS AND METHODS: 23 athymic nude rats, bearing human colon carcinoma xenografts (HT-29 were examined before and after 6 days of treatment with regorafenib (n = 12 or placebo (n = 11 in a clinical 3-Tesla MRI. For DW-MRI, a single-shot EPI sequence with 9 b-values (10-800 s/mm2 was used. The apparent diffusion coefficient (ADC was calculated voxelwise and its median value over a region of interest, covering the entire tumor, was defined as the tumor ADC. Tumor volume was determined using T2-weighted images. ADC and volume changes between first and second measurement were evaluated as classifiers by a receiver-operator-characteristic (ROC analysis individually and combined using Fisher's linear discriminant analysis (FLDA. RESULTS: All ADCs and volumes are stated as median±standard deviation. Tumor ADC increased significantly in the therapy group (0.76±0.09×10(-3 mm2/s to 0.90±0.12×10(-3 mm2/s; p<0.001, with significantly higher changes of tumor ADC than in the control group (0.10±0.11×10(-3 mm2/s vs. 0.03±0.09×10(-3 mm2/s; p = 0.027. Tumor volume increased significantly in both groups (therapy: 347.8±449.1 to 405.3±823.6 mm3; p = 0.034; control: 219.7±79.5 to 443.7±141.5 mm3; p<0.001, however, the therapy group showed significantly reduced tumor growth (33.30±47.30% vs. 96.43±31.66%; p<0.001. Area under the curve and accuracy of the ADC-based ROC analysis were 0.773 and 78.3%; and for the volume change 0.886 and 82.6%. The FLDA approach yielded an AUC of 0.985 and an accuracy of 95.7%. CONCLUSIONS: Regorafenib therapy significantly increased tumor ADC after 6 days of treatment and also significantly reduced tumor growth. However, ROC analyses using each parameter individually revealed a lack of accuracy in discriminating between therapy and

Hemodynamic evaluation of the right portal vein in healthy dogs of different body weights

Directory of Open Access Journals (Sweden)

de Almeida Mariana F

2010-05-01

Full Text Available Abstract Background Doppler ultrasonography is an important tool for evaluating hepatic portal hemodynamics. However, no study in dogs of different body weights, in the range encountered in routine clinical veterinary practice, has been reported. It can be difficult to obtain an ideal insonation angle when evaluating the main portal vein, so evaluation of the right portal vein branch has been described in humans as an alternative. The aim of this study was to analyze, through Doppler ultrasonography, the hemodynamics in the right portal vein branch in dogs of different body weights. Methods Thirty normal dogs were divided in three groups by weight, in order to establish normal values for mean velocity, flow volume and portal congestion index of the right portal vein branch by means of Doppler ultrasonography. Results In all dogs ideal insonation angles were obtained for the right portal vein branch. The average velocity was similar in the three groups, but the portal congestion index and the flow volume differed, showing that the weight of the dog can influence these values. Conclusion Doppler ultrasonography for the evaluation of flow in the right branch of the portal vein could be a viable alternative, or complement, to examining the main vessel segment. This is especially so in those animals in which an ideal insonation angle for examination of the main portal vein is hard to obtain. In addition, the weight of the dog must be considered for the correct evaluation of the portal system hemodynamics, particularly for portal blood flow and the congestion index.

High b-value diffusion-weighted imaging in progressive multifocal leukoencephalopathy in HIV patients

International Nuclear Information System (INIS)

Godi, Claudia; De Vita, Enrico; Davagnanam, Indran; Tombetti, Enrico; Haddow, Lewis; Jaeger, Hans Rolf

2017-01-01

An ill-defined hyperintense edge and hypointense core on diffusion-weighted imaging (DWI) is typical of progressive multifocal leukoencephalopathy (PML). We aimed to investigate whether a b-value of 3,000 s/mm"2 (b3000) can improve visualisation of PML, or provide different structural information compared to 1,000 s/mm"2 (b1000). We retrospectively identified HIV-positive patients with confirmed PML studied under a clinical protocol including both b1000 and b3000 DWI. The rim and core of each PML lesion and normal-appearing white matter (NAWM) were outlined on trace-weighted DWI. Signal intensities, apparent diffusion coefficient (ADC) values and volumes were measured and compared between b1000 and b3000. Nine lesions from seven patients were analysed. The rim and core were better visualised on b3000, with higher signal of the rim and lower signal of the core compared to NAWM. The hyperintense rim had non-restricted average ADCs, but included foci of low ADC on both b3000 and b1000. Despite similar total lesion volumes, b3000 displayed significantly larger core and smaller rim volumes than b1000. b3000 improves visualisation of this important PML hallmark. Moreover, b3000 partly reclassifies tissue from rim into core, and might provide potentially more accurate biomarkers of PML activity and prognosis. (orig.)

High b-value diffusion-weighted imaging in progressive multifocal leukoencephalopathy in HIV patients

Energy Technology Data Exchange (ETDEWEB)

Godi, Claudia [San Raffaele Scientific Institute, Neuroradiology Department, Milan (Italy); The National Hospital for Neurology and Neurosurgery, Lysholm Department of Neuroradiology, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); De Vita, Enrico; Davagnanam, Indran [The National Hospital for Neurology and Neurosurgery, Lysholm Department of Neuroradiology, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); Tombetti, Enrico [Vita-Salute San Raffaele University, Milan (Italy); Haddow, Lewis [University College London, Centre for Sexual Health and HIV Research, Research Department of Infection and Population Health, London (United Kingdom); Jaeger, Hans Rolf [The National Hospital for Neurology and Neurosurgery, Lysholm Department of Neuroradiology, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); University College Hospital, Centre of Medical Imaging, London (United Kingdom)

2017-09-15

An ill-defined hyperintense edge and hypointense core on diffusion-weighted imaging (DWI) is typical of progressive multifocal leukoencephalopathy (PML). We aimed to investigate whether a b-value of 3,000 s/mm{sup 2} (b3000) can improve visualisation of PML, or provide different structural information compared to 1,000 s/mm{sup 2} (b1000). We retrospectively identified HIV-positive patients with confirmed PML studied under a clinical protocol including both b1000 and b3000 DWI. The rim and core of each PML lesion and normal-appearing white matter (NAWM) were outlined on trace-weighted DWI. Signal intensities, apparent diffusion coefficient (ADC) values and volumes were measured and compared between b1000 and b3000. Nine lesions from seven patients were analysed. The rim and core were better visualised on b3000, with higher signal of the rim and lower signal of the core compared to NAWM. The hyperintense rim had non-restricted average ADCs, but included foci of low ADC on both b3000 and b1000. Despite similar total lesion volumes, b3000 displayed significantly larger core and smaller rim volumes than b1000. b3000 improves visualisation of this important PML hallmark. Moreover, b3000 partly reclassifies tissue from rim into core, and might provide potentially more accurate biomarkers of PML activity and prognosis. (orig.)

Gravimetric gas determinations for volume calibration

International Nuclear Information System (INIS)

Gibbs, P.W.

1991-01-01

Gravimetric measurements of gases is one of the methods available for calibrating gas volumes. By inputting a known quantity of gas and measuring the resulting pressure and temperature, the system volume can be calculated using gas law principles. Historically, this method has been less accurate due to the difficulty in the mass determination. This difficulty comes from several sources. Two examples are the large tare weight of the gas container relative to the weight of gas and the external volume of the gas container relative to the standards. The application of a gravimetric gas determination to tank volume calibrations at the savannah River Site is discussed. Mass determinations on a 25,00 gram gas container were such that a 1500 gram quantity of gas was routinely determined to within ±0.2 gram at the 99% confidence level. In this paper the weighting design and the methods used to address the difficulties of the mass determination are detailed

Volume de iogurte light e sensações subjetivas do apetite de homens eutróficos e com excesso de peso Volume of light yogurt and subjective appetite sensations in normal-weight and overweight men

Directory of Open Access Journals (Sweden)

Luciana Neri Nobre

2006-10-01

Full Text Available OBJETIVO: Avaliar, independentemente de outras variáveis, o efeito do volume de iogurte light sobre os parâmetros de ingestão alimentar de homens saudáveis. MÉTODOS: Foi feita incorporação de ar ao iogurte por adição de um produto comercialmente disponível -Emustab® - (6g/300ml com posterior homogeneização em liqüidificador semi-industrial. Utilizaram-se três volumes de iogurte: 300, 450 e 600ml. Trabalhou-se com 20 participantes saudáveis, sendo 10 eutróficos, com índice de massa corporal entre 19 e 24,9kg/m² e 10 com excesso de peso, índice de massa corporal >25kg/m². Cada um deles recebeu um volume de iogurte em três diferentes dias, pela manhã, em jejum de 12 horas. Uma escala de analogia visual foi utilizada, num período de 4 horas e 30 minutos após ingestão de cada volume do iogurte, para avaliar sensações subjetivas de saciedade, fome e desejo por alimentos específicos. RESULTADOS: Os volumes do iogurte light afetaram a saciedade dos dois grupos estudados, sendo que o maior volume exerceu melhor essa ação (pOBJECTIVE: This study aimed to evaluate the effect of light yogurt volume on the food intake of healthy men regardless of other variables. METHODS: Air was added to the yogurt by mixing it with a commercially available product, Emustab®, (6g/300ml and homogenized in a semi-industrial blender. Three volumes of yogurt were used: 300, 450 and 600ml. Twenty healthy volunteers participated in the study, 10 with normal weight, Body Mass Index from 19 to 24.9kg/m² and 10 with excess weight, Body Mass Index >25kg/m². Each one of them was given a yogurt volume in three different days in the morning, after a 12 hour fast. After the intake of each yogurt volume, a visual analog scale was used to assess the subjective sensations of satiety, hunger and desire for specific foods. RESULTS: Light yogurt volumes affected the satiety of both studied groups and the greater volume was more effective (p<0.01. The highest

Market value calculation and the solution of circularity between value and the weighted average cost of capital WACC

Directory of Open Access Journals (Sweden)

Ignacio Vélez-Pareja

2009-12-01

Full Text Available Most finance textbooks present the Weighted Average Cost of Capital (WACC calculation as: WACC = Kd×(1-T×D% + Ke×E%, where Kd is the cost of debt before taxes, T is the tax rate, D% is the percentage of debt on total value, Ke is the cost of equity and E% is the percentage of equity on total value. All of them precise (but not with enough emphasis that the values to calculate D% y E% are market values. Although they devote special space and thought to calculate Kd and Ke, little effort is made to the correct calculation of market values. This means that there are several points that are not sufficiently dealt with: Market values, location in time, occurrence of tax payments, WACC changes in time and the circularity in calculating WACC. The purpose of this note is to clear up these ideas, solve the circularity problem and emphasize in some ideas that usually are looked over. Also, some suggestions are presented on how to calculate, or estimate, the equity cost of capital.

Effect of high and low ultrafiltration volume during hemodialysis on relative blood volume

NARCIS (Netherlands)

Dasselaar, JJ; de Jong, PE; Huisman, RM; Franssen, CFM

2006-01-01

Achieving an optimal posthemodialysis hydration status may be difficult because objective criteria for dry weight are lacking. Both relative blood volume changes (Delta RBV) at the end of hemodialysis and Delta RBV normalized for ultrafiltration volume (Delta RBV/UF ratio) have been reported to

Forecast Accuracy and Economic Gains from Bayesian Model Averaging using Time Varying Weights

NARCIS (Netherlands)

L.F. Hoogerheide (Lennart); R.H. Kleijn (Richard); H.K. van Dijk (Herman); M.J.C.M. Verbeek (Marno)

2009-01-01

textabstractSeveral Bayesian model combination schemes, including some novel approaches that simultaneously allow for parameter uncertainty, model uncertainty and robust time varying model weights, are compared in terms of forecast accuracy and economic gains using financial and macroeconomic time

Changes in body weight, C-reactive protein, and total adiponectin in non-obese women after 12 months of a small-volume, home-based exercise program.

Science.gov (United States)

Mediano, Mauro Felippe Felix; Neves, Fabiana Alves; Cunha, Alessandra Cordeiro de Souza Rodrigues; Souza, Erica Patricia Garcia de; Moura, Anibal Sanchez; Sichieri, Rosely

2013-01-01

Our objective was to evaluate the effects of small-volume, home-based exercise combined with slight caloric restriction on the inflammatory markers C-reactive protein and adiponectin. In total, 54 women were randomly assigned to one of two groups for exercise intervention: the control or home-based exercise groups. Weight, waist and hip circumferences, and inflammatory markers were measured at baseline and after 6 and 12 months. Women allocated to the home-based exercise group received a booklet explaining the physical exercises to be practiced at home at least 3 times per week, 40 minutes per session, at low-to-moderate intensity. All participants received dietary counseling aimed at reducing caloric intake by 100-300 calories per day, with a normal distribution of macro-nutrients (26-28% of energy as fat). Clinicaltrials.gov: NCT01206413 RESULTS: The home-based exercise group showed a significantly greater reduction in weight and body mass index at six months, but no difference between groups was observed thereafter. With regard to the inflammatory markers, a greater but non-statistically significant reduction was found for C-reactive protein in the home-based exercise group at six months; however, this difference disappeared after adjusting for weight change. No differences in adiponectin were found at the 6- or 12-month follow-up. Small-volume, home-based exercise did not promote changes in inflammatory markers independent of weight change.

Preoperative weight loss in super-obese patients: study of the rate of weight loss and its effects on surgical morbidity

Directory of Open Access Journals (Sweden)

Marco Aurelio Santo

2014-01-01

Full Text Available OBJECTIVES: The incidence of obesity and particularly super obesity, has increased tremendously. At our institution, super obesity represents 30.1% of all severely obese individuals in the bariatric surgery program. In super obesity, surgical morbidity is higher and the results are worse compared with morbid obesity, independent of the surgical technique. The primary strategy for minimizing complications in these patients is to decrease the body mass index before surgery. Preoperative weight reduction can be achieved by a hypocaloric diet, drug therapy, an intragastric balloon, or hospitalization. The objective of this study was to analyze the results of a period of hospitalization for preoperative weight loss in a group of super-obese patients. METHODS: Twenty super-obese patients were submitted to a weight loss program between 2006 and 2010. The mean patient age was 46 years (range 21-59. The mean BMI was 66 kg/m2 (range 51-98 and 12 were women. The average hospital stay was 19.9 weeks and the average weight loss was 19% of the initial weight (7-37%. The average caloric intake was 5 kcal/kg/day. After the weight loss program, the patients underwent gastric bypass surgery. RESULTS: The statistical analysis revealed that after 14 weeks of treatment (15% loss of initial weight, the weight loss was not significant. All patients had satisfactory surgical recovery and were discharged after an average of 4.6 days. CONCLUSION: In super obesity, preoperative weight loss is an important method for reducing surgical risks. Hospitalization and a hypocaloric diet are safe and effective. After 14 weeks, the weight loss rate stabilized, signaling the time of surgical intervention in our study.

Optimizing Prediction Using Bayesian Model Averaging: Examples Using Large-Scale Educational Assessments.

Science.gov (United States)

Kaplan, David; Lee, Chansoon

2018-01-01

This article provides a review of Bayesian model averaging as a means of optimizing the predictive performance of common statistical models applied to large-scale educational assessments. The Bayesian framework recognizes that in addition to parameter uncertainty, there is uncertainty in the choice of models themselves. A Bayesian approach to addressing the problem of model uncertainty is the method of Bayesian model averaging. Bayesian model averaging searches the space of possible models for a set of submodels that satisfy certain scientific principles and then averages the coefficients across these submodels weighted by each model's posterior model probability (PMP). Using the weighted coefficients for prediction has been shown to yield optimal predictive performance according to certain scoring rules. We demonstrate the utility of Bayesian model averaging for prediction in education research with three examples: Bayesian regression analysis, Bayesian logistic regression, and a recently developed approach for Bayesian structural equation modeling. In each case, the model-averaged estimates are shown to yield better prediction of the outcome of interest than any submodel based on predictive coverage and the log-score rule. Implications for the design of large-scale assessments when the goal is optimal prediction in a policy context are discussed.

Modelling lidar volume-averaging and its significance to wind turbine wake measurements

DEFF Research Database (Denmark)

Meyer Forsting, Alexander Raul; Troldborg, Niels; Borraccino, Antoine

2017-01-01

gradients, like the rotor wake, can it be detrimental. Hence, an efficient algorithm mimicking lidar flow sampling is presented, which considers both pulsed and continous-wave lidar weighting functions. The flow-field around a 2.3 MW turbine is simulated using Detached Eddy Simulation in combination...

Early weight loss predicts weight loss treatment response regardless of binge-eating disorder status and pretreatment weight change.

Science.gov (United States)

Barnes, Rachel D; Ivezaj, Valentina; Pittman, Brian P; Grilo, Carlos M

2018-04-10

Individuals seeking weight loss treatment have diverse pretreatment weight trajectories, and once enrolled, individuals' response to weight loss treatments also varies greatly and may be influenced by the presence of binge-eating disorder (BED). Reported average weight losses may obscure these considerable differences. This study examined whether BED status and different weight-related change variables are associated with successful weight loss treatment outcomes in a controlled treatment study. Participants (N = 89) with overweight/obesity, with and without BED, participated in a 3-month weight loss trial in primary care with 3- and 12-month follow-ups. We tested the prognostic significance of four weight-related change variables (the last supper, early weight loss, pretreatment weight trajectory, weight suppression) on outcomes (weight loss-overall, weight loss-"subsequent," weight loss during second half of treatment). Early weight loss was positively associated with weight loss-overall at post-treatment, and at 3-month and 12-month follow-up. Early weight loss was positively associated with weight loss-subsequent at post-treatment only. No other weight-related variables were significantly associated with weight loss. Models including BED status and treatment condition were not significant. Participants with early weight loss were more likely to continue losing weight, regardless of BED status or treatment condition. The results highlight the importance of early dedication to weight loss treatment to increase the likelihood of positive outcomes. © 2018 Wiley Periodicals, Inc.

"Whatever average is:" understanding African-American mothers' perceptions of infant weight, growth, and health.

Science.gov (United States)

Thompson, Amanda L; Adair, Linda; Bentley, Margaret E

2014-06-01

Biomedical researchers have raised concerns that mothers' inability to recognize infant and toddler overweight poses a barrier to stemming increasing rates of overweight and obesity, particularly among low-income or minority mothers. Little anthropological research has examined the sociocultural, economic or structural factors shaping maternal perceptions of infant and toddler size or addressed biomedical depictions of maternal misperception as a "socio-cultural problem." We use qualitative and quantitative data from 237 low-income, African-American mothers to explore how they define 'normal' infant growth and infant overweight. Our quantitative results document that mothers' perceptions of infant size change with infant age, are sensitive to the size of other infants in the community, and are associated with concerns over health and appetite. Qualitative analysis documents that mothers are concerned with their children's weight status and assess size in relation to their infants' cues, local and societal norms of appropriate size, interactions with biomedicine, and concerns about infant health and sufficiency. These findings suggest that mothers use multiple models to interpret and respond to child weight. An anthropological focus on the complex social and structural factors shaping what is considered 'normal' and 'abnormal' infant weight is critical for shaping appropriate and successful interventions.

7 CFR 981.61 - Redetermination of kernel weight.

Science.gov (United States)

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Redetermination of kernel weight. 981.61 Section 981... GROWN IN CALIFORNIA Order Regulating Handling Volume Regulation § 981.61 Redetermination of kernel weight. The Board, on the basis of reports by handlers, shall redetermine the kernel weight of almonds...

No overall relationship between average daily weight gain and the serological response to Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae in eight chronically infected Danish swine herds

DEFF Research Database (Denmark)

Andreasen, Margit; Mousing, Jan; Thomsen, Lars Krogsgård

2001-01-01

approximately 4 weeks of age), and sera were analyzed for antibodies to Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae serotypes 2, 5-7 and 12. Mixed analysis of covariance analyzed the relationship between the average daily weight gain and a categorical variable defining seroconversion as none...... most pigs included in the study were subclinically infected, or because a temporary negative influence of the infections is hidden due to an increased growth in the period following infection. In conclusion. at least in these eight herds, seroresponses to M. hyopneumoniae and A. pleuropneumoniae could...

Determination of the blood volume of rabbits (1963)

International Nuclear Information System (INIS)

Bernard, Y.; Pierotti, Th.; Rinaldi, R.

1963-01-01

The knowledge of the ratio of the blood volume to the weight of an animal is of a great deal in various experiments. Therefore authors have decided to determine this ratio for rabbits by using chromium 51. Results show that the blood volume represents about 54.4 g per kilogram of body weight. (authors) [fr

Improvement of internal tumor volumes of non-small cell lung cancer patients for radiation treatment planning using interpolated average CT in PET/CT.

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Yao-Ching Wang

Full Text Available Respiratory motion causes uncertainties in tumor edges on either computed tomography (CT or positron emission tomography (PET images and causes misalignment when registering PET and CT images. This phenomenon may cause radiation oncologists to delineate tumor volume inaccurately in radiotherapy treatment planning. The purpose of this study was to analyze radiology applications using interpolated average CT (IACT as attenuation correction (AC to diminish the occurrence of this scenario. Thirteen non-small cell lung cancer patients were recruited for the present comparison study. Each patient had full-inspiration, full-expiration CT images and free breathing PET images by an integrated PET/CT scan. IACT for AC in PET(IACT was used to reduce the PET/CT misalignment. The standardized uptake value (SUV correction with a low radiation dose was applied, and its tumor volume delineation was compared to those from HCT/PET(HCT. The misalignment between the PET(IACT and IACT was reduced when compared to the difference between PET(HCT and HCT. The range of tumor motion was from 4 to 17 mm in the patient cohort. For HCT and PET(HCT, correction was from 72% to 91%, while for IACT and PET(IACT, correction was from 73% to 93% (*p<0.0001. The maximum and minimum differences in SUVmax were 0.18% and 27.27% for PET(HCT and PET(IACT, respectively. The largest percentage differences in the tumor volumes between HCT/PET and IACT/PET were observed in tumors located in the lowest lobe of the lung. Internal tumor volume defined by functional information using IACT/PET(IACT fusion images for lung cancer would reduce the inaccuracy of tumor delineation in radiation therapy planning.

7 CFR 981.60 - Determination of kernel weight.

Science.gov (United States)

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Determination of kernel weight. 981.60 Section 981.60... Regulating Handling Volume Regulation § 981.60 Determination of kernel weight. (a) Almonds for which settlement is made on kernel weight. All lots of almonds, whether shelled or unshelled, for which settlement...

Uncertainty associated with assessing semen volume: are volumetric and gravimetric methods that different?

Science.gov (United States)

Woodward, Bryan; Gossen, Nicole; Meadows, Jessica; Tomlinson, Mathew

2016-12-01

The World Health Organization laboratory manual for the examination of human semen suggests that an indirect measurement of semen volume by weighing (gravimetric method) is more accurate than a direct measure using a serological pipette. A series of experiments were performed to determine the level of discrepancy between the two methods using pipettes and a balance which had been calibrated to a traceable standard. The median weights of 1.0ml and 5.0ml of semen were 1.03 g (range 1.02-1.05 g) and 5.11 g (range 4.95-5.16 g), respectively, suggesting a density for semen between 1.03g and 1.04 g/ml. When the containers were re-weighed after the removal of 5.0 ml semen using a serological pipette, the mean residual loss was 0.12 ml (120 μl) or 0.12 g (median 100 μl, range 70-300 μl). Direct comparison of the volumetric and gravimetric methods in a total of 40 samples showed a mean difference of 0.25ml (median 0.32 ± 0.67ml) representing an error of 8.5%. Residual semen left in the container by weight was on average 0.11 g (median 0.10 g, range 0.05-0.19 g). Assuming a density of 1 g/ml then the average error between volumetric and gravimetric methods was approximately 8% (p gravimetric measurement of semen volume. Laboratories may therefore prefer to provide in-house quality assurance data in order to be satisfied that 'estimating' semen volume is 'fit for purpose' as opposed to assuming a lower uncertainty associated with the WHO recommended method.

Comparison of T1-weighted 2D TSE, 3D SPGR, and two-point 3D Dixon MRI for automated segmentation of visceral adipose tissue at 3 Tesla.

Science.gov (United States)

Fallah, Faezeh; Machann, Jürgen; Martirosian, Petros; Bamberg, Fabian; Schick, Fritz; Yang, Bin

2017-04-01

To evaluate and compare conventional T1-weighted 2D turbo spin echo (TSE), T1-weighted 3D volumetric interpolated breath-hold examination (VIBE), and two-point 3D Dixon-VIBE sequences for automatic segmentation of visceral adipose tissue (VAT) volume at 3 Tesla by measuring and compensating for errors arising from intensity nonuniformity (INU) and partial volume effects (PVE). The body trunks of 28 volunteers with body mass index values ranging from 18 to 41.2 kg/m 2 (30.02 ± 6.63 kg/m 2 ) were scanned at 3 Tesla using three imaging techniques. Automatic methods were applied to reduce INU and PVE and to segment VAT. The automatically segmented VAT volumes obtained from all acquisitions were then statistically and objectively evaluated against the manually segmented (reference) VAT volumes. Comparing the reference volumes with the VAT volumes automatically segmented over the uncorrected images showed that INU led to an average relative volume difference of -59.22 ± 11.59, 2.21 ± 47.04, and -43.05 ± 5.01 % for the TSE, VIBE, and Dixon images, respectively, while PVE led to average differences of -34.85 ± 19.85, -15.13 ± 11.04, and -33.79 ± 20.38 %. After signal correction, differences of -2.72 ± 6.60, 34.02 ± 36.99, and -2.23 ± 7.58 % were obtained between the reference and the automatically segmented volumes. A paired-sample two-tailed t test revealed no significant difference between the reference and automatically segmented VAT volumes of the corrected TSE (p = 0.614) and Dixon (p = 0.969) images, but showed a significant VAT overestimation using the corrected VIBE images. Under similar imaging conditions and spatial resolution, automatically segmented VAT volumes obtained from the corrected TSE and Dixon images agreed with each other and with the reference volumes. These results demonstrate the efficacy of the signal correction methods and the similar accuracy of TSE and Dixon imaging for automatic volumetry of VAT at 3 Tesla.

Measurement of flux-weighted average cross-sections and isomeric yield ratios for {sup 103}Rh(γ, xn) reactions in the bremsstrahlung end-point energies of 55 and 60 MeV

Energy Technology Data Exchange (ETDEWEB)

Shakilur Rahman, Md.; Kim, Kwangsoo; Kim, Guinyun; Nadeem, Muhammad; Thi Hien, Nguyen; Shahid, Muhammad [Kyungpook National University, Department of Physics, Daegu (Korea, Republic of); Naik, Haladhara [Bhabha Atomic Research Centre, Radiochemistry Division, Mumbai (India); Yang, Sung-Chul; Cho, Young-Sik; Lee, Young-Ouk [Korea Atomic Energy Research Institute, Nuclear Data Center, Daejeon (Korea, Republic of); Shin, Sung-Gyun; Cho, Moo-Hyun [Pohang University of Science and Technology, Division of Advanced Nuclear Engineering, Pohang (Korea, Republic of); Woo Lee, Man; Kang, Yeong-Rok; Yang, Gwang-Mo [Dongnam Institute of Radiological and Medical Science, Research Center, Busan (Korea, Republic of); Ro, Tae-Ik [Dong-A University, Department of Materials Physics, Busan (Korea, Republic of)

2016-07-15

We measured the flux-weighted average cross-sections and the isomeric yield ratios of {sup 99m,g,100m,g,101m,g,102m,g}Rh in the {sup 103}Rh(γ, xn) reactions with the bremsstrahlung end-point energies of 55 and 60 MeV by the activation and the off-line γ-ray spectrometric technique, using the 100 MeV electron linac at the Pohang Accelerator Laboratory (PAL), Korea. The flux-weighted average cross-sections were calculated by using the computer code TALYS 1.6 based on mono-energetic photons, and compared with the present experimental data. The flux-weighted average cross-sections of {sup 103}Rh(γ, xn) reactions in intermediate bremsstrahlung energies are the first time measurement and are found to increase from their threshold value to a particular value, where the other reaction channels open up. Thereafter, it decreases with bremsstrahlung energy due to its partition in different reaction channels. The isomeric yield ratios (IR) of {sup 99m,g,100m,g,101m,g,102m,g}Rh in the {sup 103}Rh(γ, xn) reactions from the present work were compared with the literature data in the {sup 103}Rh(d, x), {sup 102-99}Ru(p, x), {sup 103}Rh(α, αn), {sup 103}Rh(α, 2p3n), {sup 102}Ru({sup 3}He, x), and {sup 103}Rh(γ, xn) reactions. It was found that the IR values of {sup 102,101,100,99}Rh in all these reactions increase with the projectile energy, which indicates the role of excitation energy. At the same excitation energy, the IR values of {sup 102,101,100,99}Rh are higher in the charged particle-induced reactions than in the photon-induced reaction, which indicates the role of input angular momentum. (orig.)

Maximal oxygen consumption, respiratory volume and some related factors in fire-fighting personnel

Directory of Open Access Journals (Sweden)

Touraj Khazraee

2017-01-01

Full Text Available Background: Firefighters for difficult activities and rescue of damaged people must be in appropriate physical ability. Maximal oxygen capacity is an indicator for diagnosis of physical ability of workers. This study aimed to assess the cardiorespiratory system and its related factors in firefighters. Methods: This study was conducted on 110 firefighters from various stations. An self-administered questionnaire (respiratory disorders questionnaire, Tuxworth-Shahnavaz step test, and pulmonary function test was used to collection of required data. Average of humidity and temperature was 52% and 17°C, respectively. Background average noise levels were between 55 and 65 dB. Data were analyzed using SPSS software (version 19. Results: The mean age of the study participants was 32 ± 6.2 years. The means of forced vital capacity (FVC, forced expiratory volume in 1 s (FEV1, and FEV1/FVC were 92% ±9.4%, 87% ±9.2%, and 80% ±6.1%, respectively. The participants' mean VO2-max was 2.79 ± 0.29 L/min or 37.34 ± 4.27 ml/kg body weight per minute. The results revealed that weight has a direct association with vital capacity (VC, FVC, and peak expiratory flow. In addition, height was directly associated with VC, FVC, and VO2-max (P < 0.05. However, there was an inverse and significant association between height and FEV1/FVC (r = −0.23,P< 0.05. Height, weight, body mass index, and waist circumference were directly associated with VO2-max. Conclusions: The findings of this study showed that the amount of maximum oxygen consumption is close with the proposed range of this parameter among firefighters in other studies. Furthermore, the results of the study revealed that individuals had normal amounts of lung volume index. This issue can be attributed to the appropriate usage of respiratory masks.

Bounds on Average Time Complexity of Decision Trees

KAUST Repository

Chikalov, Igor

2011-01-01

In this chapter, bounds on the average depth and the average weighted depth of decision trees are considered. Similar problems are studied in search theory [1], coding theory [77], design and analysis of algorithms (e.g., sorting) [38]. For any diagnostic problem, the minimum average depth of decision tree is bounded from below by the entropy of probability distribution (with a multiplier 1/log2 k for a problem over a k-valued information system). Among diagnostic problems, the problems with a complete set of attributes have the lowest minimum average depth of decision trees (e.g, the problem of building optimal prefix code [1] and a blood test study in assumption that exactly one patient is ill [23]). For such problems, the minimum average depth of decision tree exceeds the lower bound by at most one. The minimum average depth reaches the maximum on the problems in which each attribute is "indispensable" [44] (e.g., a diagnostic problem with n attributes and kn pairwise different rows in the decision table and the problem of implementing the modulo 2 summation function). These problems have the minimum average depth of decision tree equal to the number of attributes in the problem description. © Springer-Verlag Berlin Heidelberg 2011.

Stereological estimation of the mean and variance of nuclear volume from vertical sections

DEFF Research Database (Denmark)

Sørensen, Flemming Brandt

1991-01-01

The application of assumption-free, unbiased stereological techniques for estimation of the volume-weighted mean nuclear volume, nuclear vv, from vertical sections of benign and malignant nuclear aggregates in melanocytic skin tumours is described. Combining sampling of nuclei with uniform...... probability in a physical disector and Cavalieri's direct estimator of volume, the unbiased, number-weighted mean nuclear volume, nuclear vN, of the same benign and malignant nuclear populations is also estimated. Having obtained estimates of nuclear volume in both the volume- and number distribution...... to the larger malignant nuclei. Finally, the variance in the volume distribution of nuclear volume is estimated by shape-independent estimates of the volume-weighted second moment of the nuclear volume, vv2, using both a manual and a computer-assisted approach. The working procedure for the description of 3-D...

Quantified moving average strategy of crude oil futures market based on fuzzy logic rules and genetic algorithms

Science.gov (United States)

Liu, Xiaojia; An, Haizhong; Wang, Lijun; Guan, Qing

2017-09-01

The moving average strategy is a technical indicator that can generate trading signals to assist investment. While the trading signals tell the traders timing to buy or sell, the moving average cannot tell the trading volume, which is a crucial factor for investment. This paper proposes a fuzzy moving average strategy, in which the fuzzy logic rule is used to determine the strength of trading signals, i.e., the trading volume. To compose one fuzzy logic rule, we use four types of moving averages, the length of the moving average period, the fuzzy extent, and the recommend value. Ten fuzzy logic rules form a fuzzy set, which generates a rating level that decides the trading volume. In this process, we apply genetic algorithms to identify an optimal fuzzy logic rule set and utilize crude oil futures prices from the New York Mercantile Exchange (NYMEX) as the experiment data. Each experiment is repeated for 20 times. The results show that firstly the fuzzy moving average strategy can obtain a more stable rate of return than the moving average strategies. Secondly, holding amounts series is highly sensitive to price series. Thirdly, simple moving average methods are more efficient. Lastly, the fuzzy extents of extremely low, high, and very high are more popular. These results are helpful in investment decisions.

Modelling of an intermediate pressure microwave oxygen discharge reactor: from stationary two-dimensional to time-dependent global (volume-averaged) plasma models

International Nuclear Information System (INIS)

Kemaneci, Efe; Graef, Wouter; Rahimi, Sara; Van Dijk, Jan; Kroesen, Gerrit; Carbone, Emile; Jimenez-Diaz, Manuel

2015-01-01

A microwave-induced oxygen plasma is simulated using both stationary and time-resolved modelling strategies. The stationary model is spatially resolved and it is self-consistently coupled to the microwaves (Jimenez-Diaz et al 2012 J. Phys. D: Appl. Phys. 45 335204), whereas the time-resolved description is based on a global (volume-averaged) model (Kemaneci et al 2014 Plasma Sources Sci. Technol. 23 045002). We observe agreement of the global model data with several published measurements of microwave-induced oxygen plasmas in both continuous and modulated power inputs. Properties of the microwave plasma reactor are investigated and corresponding simulation data based on two distinct models shows agreement on the common parameters. The role of the square wave modulated power input is also investigated within the time-resolved description. (paper)

Influence of dispatching rules on average production lead time for multi-stage production systems.

Science.gov (United States)

Hübl, Alexander; Jodlbauer, Herbert; Altendorfer, Klaus

2013-08-01

In this paper the influence of different dispatching rules on the average production lead time is investigated. Two theorems based on covariance between processing time and production lead time are formulated and proved theoretically. Theorem 1 links the average production lead time to the "processing time weighted production lead time" for the multi-stage production systems analytically. The influence of different dispatching rules on average lead time, which is well known from simulation and empirical studies, can be proved theoretically in Theorem 2 for a single stage production system. A simulation study is conducted to gain more insight into the influence of dispatching rules on average production lead time in a multi-stage production system. We find that the "processing time weighted average production lead time" for a multi-stage production system is not invariant of the applied dispatching rule and can be used as a dispatching rule independent indicator for single-stage production systems.

Weighted OFDM for wireless multipath channels

DEFF Research Database (Denmark)

Prasad, Ramjee; Nikookar, H.

2000-01-01

In this paper the novel method of "weighted OFDM" is addressed. Different types of weighting factors (including Rectangular, Bartlett, Gaussian. Raised cosine, Half-sin and Shanon) are considered. The impact of weighting of OFDM on the peak-to-average power ratio (PAPR) is investigated by means...... of simulation and is compared for the above mentioned weighting factors. Results show that by weighting of the OFDM signal the PAPR reduces. Bit error performance of weighted multicarrier transmission over a multipath channel is also investigated. Results indicate that there is a trade off between PAPR...

OBSERVATION ON INCREASE IN WEIGHT OF LOW BIRTH WEIGHT (LBW BABIES BY IMPLEMENTING KANGAROO MOTHER CARE (KMC TECHNIQUE

Directory of Open Access Journals (Sweden)

Purnendu Kumar Singh

2014-12-01

Full Text Available Kangaroo Mother Care (KMC is a practical technique for nursing of low birth weight babies by direct skin to contact with the mother. This study was undertaken to observe and record the effect of KMC with focus on increase in weight of at term low birth weight (LBW babies weighing less than 2000 grams. The study was conducted over thirty six month’s period from July 2011 to June 2014. The method of care consisted of skin to skin contact between the mother and the infant along with exclusive breast milk. Upon implementation of KMC babies under observation showed satisfactory gain in weight of average 25grams per day and an average hospital stay of 10 days. KMC aims towards achieving good weight gain in LBW babies. It is a simple hassle free technique which can be implemented at all levels of health care.

Analysis of birth weights of a rural hospital

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Ashtekar Shyam

2010-01-01

Full Text Available Background: Low birth weight remains a major reason behind childhood malnutrition. The NFHS findings show no dent in this problem. Objective: This study was undertaken to explore change in birth weights in a period from 1989 to 2007 and any associations thereof. Materials and Methods: All birth records of a private rural hospital spanning two decades (1989-2007 were analyzed for birth weight, age of mother, gender, birth order of the baby, proportion of pre-term babies and low birth weight babies. Results: No change was observed in the average birth weights (average 2.71 kg over the period. Although the birth weight shows some expected variance with the age of mother, it was found to have no relation with the baby′s birth order and gender. The low birth weight proportion is about 24% and shows little difference before and after the series midpoint of year 1998. Conclusion: The birth weights have hardly changed in this population in the two decades.

Analysis of Birth Weights of a Rural Hospital

Science.gov (United States)

Ashtekar, Shyam V; Kulkarni, Madhav B; Sadavarte, Vaishali S; Ashtekar, Ratna S

2010-01-01

Background: Low birth weight remains a major reason behind childhood malnutrition. The NFHS findings show no dent in this problem. Objective: This study was undertaken to explore change in birth weights in a period from 1989 to 2007 and any associations thereof. Materials and Methods: All birth records of a private rural hospital spanning two decades (1989-2007) were analyzed for birth weight, age of mother, gender, birth order of the baby, proportion of pre-term babies and low birth weight babies. Results: No change was observed in the average birth weights (average 2.71 kg) over the period. Although the birth weight shows some expected variance with the age of mother, it was found to have no relation with the baby’s birth order and gender. The low birth weight proportion is about 24% and shows little difference before and after the series midpoint of year 1998. Conclusion: The birth weights have hardly changed in this population in the two decades. PMID:20922101

Calculating ensemble averaged descriptions of protein rigidity without sampling.

Science.gov (United States)

González, Luis C; Wang, Hui; Livesay, Dennis R; Jacobs, Donald J

2012-01-01

Previous works have demonstrated that protein rigidity is related to thermodynamic stability, especially under conditions that favor formation of native structure. Mechanical network rigidity properties of a single conformation are efficiently calculated using the integer body-bar Pebble Game (PG) algorithm. However, thermodynamic properties require averaging over many samples from the ensemble of accessible conformations to accurately account for fluctuations in network topology. We have developed a mean field Virtual Pebble Game (VPG) that represents the ensemble of networks by a single effective network. That is, all possible number of distance constraints (or bars) that can form between a pair of rigid bodies is replaced by the average number. The resulting effective network is viewed as having weighted edges, where the weight of an edge quantifies its capacity to absorb degrees of freedom. The VPG is interpreted as a flow problem on this effective network, which eliminates the need to sample. Across a nonredundant dataset of 272 protein structures, we apply the VPG to proteins for the first time. Our results show numerically and visually that the rigidity characterizations of the VPG accurately reflect the ensemble averaged [Formula: see text] properties. This result positions the VPG as an efficient alternative to understand the mechanical role that chemical interactions play in maintaining protein stability.

Tailoring dietary approaches for weight loss.

Science.gov (United States)

Gardner, C D

2012-07-01

Although the 'Low-Fat' diet was the predominant public health recommendation for weight loss and weight control for the past several decades, the obesity epidemic continued to grow during this time period. An alternative 'low-carbohydrate' (Low-Carb) approach, although originally dismissed and even vilified, was comparatively tested in a series of studies over the past decade, and has been found in general to be as effective, if not more, as the Low-Fat approach for weight loss and for several related metabolic health measures. From a glass half full perspective, this suggests that there is more than one choice for a dietary approach to lose weight, and that Low-Fat and Low-Carb diets may be equally effective. From a glass half empty perspective, the average amount of weight lost on either of these two dietary approaches under the conditions studied, particularly when followed beyond 1 year, has been modest at best and negligible at worst, suggesting that the two approaches may be equally ineffective. One could resign themselves at this point to focusing on calories and energy intake restriction, regardless of macronutrient distributions. However, before throwing out the half-glass of water, it is worthwhile to consider that focusing on average results may mask important subgroup successes and failures. In all weight-loss studies, without exception, the range of individual differences in weight change within any particular diet groups is orders of magnitude greater than the average group differences between diet groups. Several studies have now reported that adults with greater insulin resistance are more successful with weight loss on a lower-carbohydrate diet compared with a lower-fat diet, whereas adults with greater insulin sensitivity are equally or more successful with weight loss on a lower-fat diet compared with a lower-carbohydrate diet. Other preliminary findings suggest that there may be some promise with matching individuals with certain genotypes to

History of Smoking and Postcessation Weight Gain among Weight Loss Surgery Candidates

Science.gov (United States)

Levine, Michele D.; Kalarchian, Melissa A.; Courcoulas, Anita P.; Wisinski, Meghan S.C.; Marcus, Marsha D.

2007-01-01

Smoking cessation often results in weight gain. Although smoking cessation frequently is recommended to patients presenting for weight loss surgery (WLS), the relationship between smoking cessation and weight gain among WLS candidates is poorly understood. Thus, we sought to document the history and prevalence of smoking and smoking-related weight gain among WLS candidates. Subjects (N = 67) presenting for bariatric surgery provided demographic information, were interviewed about smoking, and weighed and measured prior to operation. Sixty-seven percent of patients reported a lifetime history of smoking, and 26.9% were current smokers. Among lifetime smokers who had attempted to quit, the average maximum amount of weight gained following smoking cessation was 28.1 pounds, but there was wide variability in postcessation weight gain. These data suggest that smoking among candidates for bariatric surgery is prevalent, and that previous cessation attempts were associated with considerable weight gain. Because patients often receive recommendations to quit smoking and lose weight prior to surgery, additional information on the impact of presurgical smoking cessation on long-tem weight control in this population is needed. PMID:17408868

Weight Changes following the Diagnosis of Type 2 Diabetes

DEFF Research Database (Denmark)

Olivarius, Niels de Fine; Siersma, Volkert Dirk; Køster-Rasmussen, Rasmus

2015-01-01

Aims: The association between recent and more distant weight changes before and after the diagnosis of type 2 diabetes has been little researched. The aim of this study is to determine the influence of patients’ weight history before diabetes diagnosis on the observed 6-year weight changes after...... diagnosis. Methods: A clinical cohort study combined with self-reported past weight history. In total 885 patients aged ≥40 years and newly diagnosed with clinical type 2 diabetes were included. Body weight was measured immediately after diabetes diagnosis and again at the 6-year follow up examination...... weight change after diagnosis. Conclusions: During the first on average 5.7 years after diagnosis of type 2 diabetes, patients generally follow a course of declining average weight, and these weight developments are related primarily to recent weight changes, body mass index, and age, but not to the more...

Post-model selection inference and model averaging

Directory of Open Access Journals (Sweden)

Georges Nguefack-Tsague

2011-07-01

Full Text Available Although model selection is routinely used in practice nowadays, little is known about its precise effects on any subsequent inference that is carried out. The same goes for the effects induced by the closely related technique of model averaging. This paper is concerned with the use of the same data first to select a model and then to carry out inference, in particular point estimation and point prediction. The properties of the resulting estimator, called a post-model-selection estimator (PMSE, are hard to derive. Using selection criteria such as hypothesis testing, AIC, BIC, HQ and Cp, we illustrate that, in terms of risk function, no single PMSE dominates the others. The same conclusion holds more generally for any penalised likelihood information criterion. We also compare various model averaging schemes and show that no single one dominates the others in terms of risk function. Since PMSEs can be regarded as a special case of model averaging, with 0-1 random-weights, we propose a connection between the two theories, in the frequentist approach, by taking account of the selection procedure when performing model averaging. We illustrate the point by simulating a simple linear regression model.

Thyroid weight with age

International Nuclear Information System (INIS)

Raulier-Fabry, C.; Hammer, R.

1965-01-01

A large number of data on thyroid weight of euthyroid subjects have been collected from the literature in this study. The most probable average weight of the gland appears to be 20 g in the adult and 2 g in the newborn. A decrease in weight has been observed during the first year of life (1 g at 6 months) and only in the second year of life the initial birth weight is reached again. The weight curve may be considered as consisting of three straight lines: from 2 to 7, from 7 to 18 and from 18 to 25 years, their slopes being respectively 0.6, 0.9 and 0.5 g/year. The variations in weight of the thyroid during adulthood are sufficiently small to consider it as having constant value between 25 and 55 years. The available information points to a negligible weight difference between sexes. (authors) [fr

Experimental validation of heterogeneity-corrected dose-volume prescription on respiratory-averaged CT images in stereotactic body radiotherapy for moving tumors

International Nuclear Information System (INIS)

Nakamura, Mitsuhiro; Miyabe, Yuki; Matsuo, Yukinori; Kamomae, Takeshi; Nakata, Manabu; Yano, Shinsuke; Sawada, Akira; Mizowaki, Takashi; Hiraoka, Masahiro

2012-01-01

The purpose of this study was to experimentally assess the validity of heterogeneity-corrected dose-volume prescription on respiratory-averaged computed tomography (RACT) images in stereotactic body radiotherapy (SBRT) for moving tumors. Four-dimensional computed tomography (CT) data were acquired while a dynamic anthropomorphic thorax phantom with a solitary target moved. Motion pattern was based on cos (t) with a constant respiration period of 4.0 sec along the longitudinal axis of the CT couch. The extent of motion (A 1 ) was set in the range of 0.0–12.0 mm at 3.0-mm intervals. Treatment planning with the heterogeneity-corrected dose-volume prescription was designed on RACT images. A new commercially available Monte Carlo algorithm of well-commissioned 6-MV photon beam was used for dose calculation. Dosimetric effects of intrafractional tumor motion were then investigated experimentally under the same conditions as 4D CT simulation using the dynamic anthropomorphic thorax phantom, films, and an ionization chamber. The passing rate of γ index was 98.18%, with the criteria of 3 mm/3%. The dose error between the planned and the measured isocenter dose in moving condition was within ± 0.7%. From the dose area histograms on the film, the mean ± standard deviation of the dose covering 100% of the cross section of the target was 102.32 ± 1.20% (range, 100.59–103.49%). By contrast, the irradiated areas receiving more than 95% dose for A 1 = 12 mm were 1.46 and 1.33 times larger than those for A 1 = 0 mm in the coronal and sagittal planes, respectively. This phantom study demonstrated that the cross section of the target received 100% dose under moving conditions in both the coronal and sagittal planes, suggesting that the heterogeneity-corrected dose-volume prescription on RACT images is acceptable in SBRT for moving tumors.

GRID PRICING VERSUS AVERAGE PRICING FOR SLAUGHTER CATTLE: AN EMPIRICAL ANALYSIS

OpenAIRE

Fausti, Scott W.; Qasmi, Bashir A.

1999-01-01

The paper compares weekly producer revenue under grid pricing and average dressed weight pricing methods for 2560 cattle over a period of 102 weeks. Regression analysis is applied to identify factors affecting the revenue differential.

Effects of Respiration-Averaged Computed Tomography on Positron Emission Tomography/Computed Tomography Quantification and its Potential Impact on Gross Tumor Volume Delineation

International Nuclear Information System (INIS)

Chi, Pai-Chun Melinda; Mawlawi, Osama; Luo Dershan; Liao Zhongxing; Macapinlac, Homer A.; Pan Tinsu

2008-01-01

Purpose: Patient respiratory motion can cause image artifacts in positron emission tomography (PET) from PET/computed tomography (CT) and change the quantification of PET for thoracic patients. In this study, respiration-averaged CT (ACT) was used to remove the artifacts, and the changes in standardized uptake value (SUV) and gross tumor volume (GTV) were quantified. Methods and Materials: We incorporated the ACT acquisition in a PET/CT session for 216 lung patients, generating two PET/CT data sets for each patient. The first data set (PET HCT /HCT) contained the clinical PET/CT in which PET was attenuation corrected with a helical CT (HCT). The second data set (PET ACT /ACT) contained the PET/CT in which PET was corrected with ACT. We quantified the differences between the two datasets in image alignment, maximum SUV (SUV max ), and GTV contours. Results: Of the patients, 68% demonstrated respiratory artifacts in the PET HCT , and for all patients the artifact was removed or reduced in the corresponding PET ACT . The impact of respiration artifact was the worst for lesions less than 50 cm 3 and located below the dome of the diaphragm. For lesions in this group, the mean SUV max difference, GTV volume change, shift in GTV centroid location, and concordance index were 21%, 154%, 2.4 mm, and 0.61, respectively. Conclusion: This study benchmarked the differences between the PET data with and without artifacts. It is important to pay attention to the potential existence of these artifacts during GTV contouring, as such artifacts may increase the uncertainties in the lesion volume and the centroid location

Effects of sprint interval training and body weight reduction on power to weight ratio in experienced cyclists.

Science.gov (United States)

Lunn, William R; Finn, Joan A; Axtell, Robert S

2009-07-01

The purpose of this study was to determine the effect of supramaximal sprint interval training (SIT), body weight reduction, and a combination of both treatments on peak and average anaerobic power to weight ratio (PPOan:Wt, APOan:Wt) by manipulating peak and average anaerobic power output (PPOan, APOan) and body weight (BW) in experienced cyclists. Participants (N = 34, age = 38.0 +/- 7.1 years) were assigned to 4 groups for a 10-week study. One group performed twice-weekly SIT sessions on a cycle ergometer while maintaining body weight (SIT). A second group did not perform SIT but intentionally reduced body weight (WR). A third group simultaneously performed SIT sessions and reduced body weight (SIT+WR). A control group cycled in their normal routine and maintained body weight (CON). The 30-second Wingate Test assessed pretest and posttest POan:Wt scores. There was a significant mean increase (p weight (kg) decreased significantly in WR and SIT + WR (80.3 +/- 13.7 to 75.3 +/- 11.9 and 78.9 +/- 10.8 to 73.4 +/- 10.8, respectively). The results demonstrate that cyclists can use SIT sessions and body weight reduction as singular training interventions to effect significant increases in anaerobic power to weight ratio, which has been correlated to enhanced aerobic cycling performance. However, the treatments were not effective as combined interventions, as there was no significant change in either PPOan:Wt or APOan:Wt in SIT + WR.

[Evaluation of pre-pregnancy weight and gestational weight gain among urban and rural women from southwestern China].

Science.gov (United States)

Dai, Zhengyan; Li, Ming; Rui, Li; Sun, Xiaohong; Pang, Xuehong; Zhou, Lan; Zeng, Guo

2014-07-01

To evaluate the situation of pre-pregnancy weight and gestational weight gain (GWG) of women in the urban and rural areas of southwest of China. Total 3391 women whose infants and young children aged 6 - 24 months were selected from urban and rural areas of Kunming, Guiyang and Chengdu cities by stratified cluster random sampling. Data of pre-pregnancy height and weight, prenatal weight and pregnancy age for subjects was obtained using a questionnaire. Pre-pregnancy BMI and GWG were calculated. According to the BMI standard for adults from WHO and GWG Guidelines from IOM (2009), the status of pre-pregnancy weight and GWG were assessed. Average BMI of pre-pregnancy for them is (20.3 +/- 2.4). Percentage of normal weight, underweight, and overweight/obesity of pre-pregnancy were 72.7%, 24.1% and 3.2% respectively. The average GWG was (14.9 +/- 6.0) kg, and there was a significant difference between urban and rural group (P lower (P women aged below 23 years old (P women aged 24 - 34 years old (P pay more attention to improve the underweight of pre-pregnancy and abnormal GWG among women in the southwest of China.

Calculation of the weighting function and determination of the depth of correlation in micro-PIV from experimental particle images

International Nuclear Information System (INIS)

Hein, M; Seemann, R; Wieneke, B

2014-01-01

Micro-particle image velocimetry (µPIV) uses volume-illumination and imaging of particles through a single microscope objective. Displacement fields are obtained by image correlation and depend on all imaged particles, including defocused particles. The measured in-plane displacement is a weighted spatial average of the true displacement, with a weighting function W(z) that depends on the optical system and flow-gradients. The characteristic width of the weighting function W(z) is also referred to as depth of correlation (DOC) and is a measure up to which distance from the focal plane particles influence the measurement, which is crucial for the interpretation of measured flow fields. We present procedures to determine the W(z) from which the DOC can be derived and to directly determine the DOC from PIV double images, generated from experimentally recorded particle images. Both procedures provide comparable DOC results. Our approach allows determination of the DOC and W(z)as a function of out of plane gradients, optical setup parameters and PIV-analysis parameters. Experimental results for different objectives and particle sizes are discussed, revealing substantial deviations from theoretical predictions for high NA air-objectives. Moreover, using the determined weighting function W(z), the correction of measured flow profiles for errors introduced by the spatial averaging is demonstrated. (paper)

Baseline-dependent averaging in radio interferometry

Science.gov (United States)

Wijnholds, S. J.; Willis, A. G.; Salvini, S.

2018-05-01

This paper presents a detailed analysis of the applicability and benefits of baseline-dependent averaging (BDA) in modern radio interferometers and in particular the Square Kilometre Array. We demonstrate that BDA does not affect the information content of the data other than a well-defined decorrelation loss for which closed form expressions are readily available. We verify these theoretical findings using simulations. We therefore conclude that BDA can be used reliably in modern radio interferometry allowing a reduction of visibility data volume (and hence processing costs for handling visibility data) by more than 80 per cent.

Comparison of Magnetic Resonance Imaging and Computed Tomography for Breast Target Volume Delineation in Prone and Supine Positions

Energy Technology Data Exchange (ETDEWEB)

Pogson, Elise M. [Centre for Medical Radiation Physics, Faculty of Engineering and Information Sciences, University of Wollongong, Wollongong (Australia); Liverpool and Macarthur Cancer Therapy Centres, Liverpool (Australia); Ingham Institute for Applied Medical Research, Liverpool (Australia); Delaney, Geoff P. [Liverpool and Macarthur Cancer Therapy Centres, Liverpool (Australia); Ingham Institute for Applied Medical Research, Liverpool (Australia); South Western Sydney Clinical School, University of New South Wales, Sydney (Australia); School of Medicine, University of Western Sydney, Sydney (Australia); Ahern, Verity [Crown Princess Mary Cancer Care Centre, Westmead Hospital, Westmead (Australia); Boxer, Miriam M. [Liverpool and Macarthur Cancer Therapy Centres, Liverpool (Australia); South Western Sydney Clinical School, University of New South Wales, Sydney (Australia); Chan, Christine [Department of Radiology, Liverpool Hospital, Liverpool (Australia); David, Steven [Peter MacCallum Cancer Centre, Melbourne (Australia); Dimigen, Marion [Department of Radiology, Liverpool Hospital, Liverpool (Australia); Harvey, Jennifer A. [School of Medicine, University of Queensland, Herston (Australia); Princess Alexandra Hospital, Woolloongabba (Australia); Koh, Eng-Siew [Liverpool and Macarthur Cancer Therapy Centres, Liverpool (Australia); Ingham Institute for Applied Medical Research, Liverpool (Australia); South Western Sydney Clinical School, University of New South Wales, Sydney (Australia); Lim, Karen [Liverpool and Macarthur Cancer Therapy Centres, Liverpool (Australia); South Western Sydney Clinical School, University of New South Wales, Sydney (Australia); Papadatos, George [Liverpool and Macarthur Cancer Therapy Centres, Liverpool (Australia); and others

2016-11-15

Purpose: To determine whether T2-weighted MRI improves seroma cavity (SC) and whole breast (WB) interobserver conformity for radiation therapy purposes, compared with the gold standard of CT, both in the prone and supine positions. Methods and Materials: Eleven observers (2 radiologists and 9 radiation oncologists) delineated SC and WB clinical target volumes (CTVs) on T2-weighted MRI and CT supine and prone scans (4 scans per patient) for 33 patient datasets. Individual observer's volumes were compared using the Dice similarity coefficient, volume overlap index, center of mass shift, and Hausdorff distances. An average cavity visualization score was also determined. Results: Imaging modality did not affect interobserver variation for WB CTVs. Prone WB CTVs were larger in volume and more conformal than supine CTVs (on both MRI and CT). Seroma cavity volumes were larger on CT than on MRI. Seroma cavity volumes proved to be comparable in interobserver conformity in both modalities (volume overlap index of 0.57 (95% Confidence Interval (CI) 0.54-0.60) for CT supine and 0.52 (95% CI 0.48-0.56) for MRI supine, 0.56 (95% CI 0.53-0.59) for CT prone and 0.55 (95% CI 0.51-0.59) for MRI prone); however, after registering modalities together the intermodality variation (Dice similarity coefficient of 0.41 (95% CI 0.36-0.46) for supine and 0.38 (0.34-0.42) for prone) was larger than the interobserver variability for SC, despite the location typically remaining constant. Conclusions: Magnetic resonance imaging interobserver variation was comparable to CT for the WB CTV and SC delineation, in both prone and supine positions. Although the cavity visualization score and interobserver concordance was not significantly higher for MRI than for CT, the SCs were smaller on MRI, potentially owing to clearer SC definition, especially on T2-weighted MR images.

Determination of the linear coefficient of thermal expansion in polymer films at the nanoscale: influence of the composition of EVA copolymers and the molecular weight of PMMA.

Science.gov (United States)

González-Benito, J; Castillo, E; Cruz-Caldito, J F

2015-07-28

Nanothermal-expansion of poly(ethylene-co-vinylacetate), EVA, and poly(methyl methacrylate), PMMA, in the form of films was measured to finally obtain linear coefficients of thermal expansion, CTEs. The simple deflection of a cantilever in an atomic force microscope, AFM, was used to monitor thermal expansions at the nanoscale. The influences of: (a) the structure of EVA in terms of its composition (vinylacetate content) and (b) the size of PMMA chains in terms of the molecular weight were studied. To carry out this, several polymer samples were used, EVA copolymers with different weight percents of the vinylacetate comonomer (12, 18, 25 and 40%) and PMMA polymers with different weight average molecular weights (33.9, 64.8, 75.600 and 360.0 kg mol(-1)). The dependencies of the vinyl acetate weight fraction of EVA and the molecular weight of PMMA on their corresponding CTEs were analyzed to finally explain them using new, intuitive and very simple models based on the rule of mixtures. In the case of EVA copolymers a simple equation considering the weighted contributions of each comonomer was enough to estimate the final CTE above the glass transition temperature. On the other hand, when the molecular weight dependence is considered the free volume concept was used as novelty. The expansion of PMMA, at least at the nanoscale, was well and easily described by the sum of the weighted contributions of the occupied and free volumes, respectively.

Determination of clothing microclimate volume

NARCIS (Netherlands)

Daanen, Hein; Hatcher, Kent; Havenith, George

2005-01-01

The average air layer thickness between human skin and clothing is an important factor in heat transfer. The trapped volume between skin and clothing is an estimator for everage air layer thickness. Several techniques are available to determine trapped volume. This study investigates the reliability

Classification of tubulo-papillary renal cortical tumours using estimates of nuclear volume

DEFF Research Database (Denmark)

Brooks, B; Sørensen, Flemming Brandt; Olsen, S

1993-01-01

The classification of renal cortical tumours is problematic, with no clear division of benign from malignant tumours. Unbiased stereological estimates of volume-weighted nuclear volume (nuclear vv) were obtained by point sampling of nuclear intercepts in a retrospective study of 36 variably sized...... = 241 microns 3) and 15 tumours classified as renal cell carcinomas with diameters > 3 cm, or aggressive histological pattern (average nuclear vv = 229 microns 3) (2p = 0.68). In this subtype of renal cortical tumours, estimates of nuclear vv do not support the historical convention of using a 3 cm...... tumour diameter as the dividing line between adenomas and carcinomas, but support the theory of a single group of tumours. As most of the truly incidental renal cortical tumours are less than 1 cm in diameter, this limit could be considered. Such small benign cortical nodules have never been reported...

Calculating ensemble averaged descriptions of protein rigidity without sampling.

Directory of Open Access Journals (Sweden)

Luis C González

Full Text Available Previous works have demonstrated that protein rigidity is related to thermodynamic stability, especially under conditions that favor formation of native structure. Mechanical network rigidity properties of a single conformation are efficiently calculated using the integer body-bar Pebble Game (PG algorithm. However, thermodynamic properties require averaging over many samples from the ensemble of accessible conformations to accurately account for fluctuations in network topology. We have developed a mean field Virtual Pebble Game (VPG that represents the ensemble of networks by a single effective network. That is, all possible number of distance constraints (or bars that can form between a pair of rigid bodies is replaced by the average number. The resulting effective network is viewed as having weighted edges, where the weight of an edge quantifies its capacity to absorb degrees of freedom. The VPG is interpreted as a flow problem on this effective network, which eliminates the need to sample. Across a nonredundant dataset of 272 protein structures, we apply the VPG to proteins for the first time. Our results show numerically and visually that the rigidity characterizations of the VPG accurately reflect the ensemble averaged [Formula: see text] properties. This result positions the VPG as an efficient alternative to understand the mechanical role that chemical interactions play in maintaining protein stability.

Effectiveness of a psychosocial weight management program for individuals with schizophrenia.

Science.gov (United States)

Niv, Noosha; Cohen, Amy N; Hamilton, Alison; Reist, Christopher; Young, Alexander S

2014-07-01

The objective of this study was to examine the effectiveness of a weight loss program for individuals with schizophrenia in usual care. The study included 146 adults with schizophrenia from two mental health clinics of the Department of Veterans Affairs. The 109 individuals who were overweight or obese were offered a 16-week, psychosocial, weight management program. Weight and Body Mass Index (BMI) were assessed at baseline, 1 year later, and at each treatment session. Only 51% of those who were overweight or obese chose to enroll in the weight management program. Participants attended an average of 6.7 treatment sessions, lost an average of 2.4 pounds, and had an average BMI decrease of 0.3. There was no significant change in weight or BMI compared to the control group. Intervention strategies that both improve utilization and yield greater weight loss need to be developed.

Stereological estimation of nuclear volume and other quantitative histopathological parameters in the prognostic evaluation of supraglottic laryngeal squamous cell carcinoma

DEFF Research Database (Denmark)

Sørensen, Flemming Brandt; Bennedbaek, O; Pilgaard, J

1989-01-01

The aim of this study was to investigate various approaches to the grading of malignancy in pre-treatment biopsies from patients with supraglottic laryngeal squamous cell carcinoma. The prospects of objective malignancy grading based on stereological estimation of the volume-weighted mean nuclear...... volume, nuclear Vv, and nuclear volume fraction, Vv(nuc/tis), along with morphometrical 2-dimensional estimation of nuclear density index, NI, and mitotic activity index, MI, were investigated and compared with the current morphological, multifactorial grading system. The reproducibility among two...... observers of the latter was poor in the material which consisted of 35 biopsy specimens. Unbiased estimates of nuclear Vv were on the average 385 microns3 (CV = 0.44), with more than 90% of the associated variance attributable to differences in nuclear Vv among individual lesions. Nuclear Vv was positively...

16 CFR 500.25 - Net quantity, average quantity, permitted variations.

Science.gov (United States)

2010-01-01

... good distribution practice and which unavoidably result in change of weight or mass or measure. (c... good packaging practice: Provided, that such variations shall not be permitted to such extent that the... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Net quantity, average quantity, permitted...

Volume measurement of the horizontal extraocular muscles using magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Nishida, Yasuhiro; Hayashi, Osamu; Nishida, Eri; Murata, Toyotaka; Aoki, Yoshiko; Inatomi, Akihiro; Kani, Kazutaka (Shiga Univ. of Medical Science, Otsu (Japan)); Mabuchi, Norihisa; Furutani, Yoshiaki

1993-07-01

The volume of the horizontal extraocular muscles of 11 normal adults and three patients with ophthalmoplegia was measured using magnetic resonance imaging (MRI). The MRI examinations were carried out with a Signa Advantage, 1.5 tesla superconductive magnetic system manufactured by General Electric. This method employs the spin echo technique with a 3.0 mm gapless slice, a 350 ms. repetition time, and a 17.0 ms. echo time. The MRI films were projected and magnified on Kent paper using an overhead projector. Then the shapes of the horizontal extraocular muscles were traced. The volume of the muscles was measured as the total weight of Kent papers which were cut out from muscle shapes in all the slices. The average volume of the normal medial and lateral rectus muscles was 690[+-]87 mm[sup 3] and 734[+-]77 mm[sup 3], respectively. Two cases of peripheral nerve palsy showed typical atrophy of the paretic muscles. A case of orbital myositis showed typical hypertrophy of the inflamed muscles. This measurement may prove useful in the analysis and evaluation of extraocular muscles, especially in ophthalmoplesia.(author).

Future use of tritium in mapping pre-bomb groundwater volumes.

Science.gov (United States)

Eastoe, C J; Watts, C J; Ploughe, M; Wright, W E

2012-01-01

The tritium input to groundwater, represented as volume-weighted mean tritium concentrations in precipitation, has been close to constant in Tucson and Albuquerque since 1992, and the decrease in tritium concentrations at the tail end of the bomb tritium pulse has ceased. To determine the future usefulness of tritium measurements in southwestern North America, volume-weighted mean tritium levels in seasonal aggregate precipitation samples have been gathered from 26 sites. The averages range from 2 to 9 tritium units (TU). Tritium concentrations increase with site latitude, and possibly with distance from the coast and with site altitude, reflecting local ratios of combination of low-tritium moisture advected from the oceans with high-tritium moisture originating near the tropopause. Tritium used alone as a tool for mapping aquifer volumes containing only pre-bomb recharge to groundwater will become ambiguous when the tritium in precipitation at the end of the bomb tritium pulse decays to levels close to the analytical detection limit. At such a time, tritium in precipitation from the last one to two decades of the bomb pulse will become indistinguishable from pre-bomb recharge. The threshold of ambiguity has already arrived in coastal areas with a mean of 2 TU in precipitation and will follow in the next three decades throughout the study region. Where the mean tritium level is near 5 TU, the threshold will occur between 2025 and 2030, given a detection limit of 0.6 TU. Similar thresholds of ambiguity, with different local timing possible, apply globally. © 2011, The Author(s). Ground Water © 2011, National Ground Water Association.

A randomised clinical trial on the efficacy of oxytetracycline dose through water medication of nursery pigs on diarrhoea, faecal shedding of Lawsonia intracellularis and average daily weight gain.

Science.gov (United States)

Larsen, Inge; Hjulsager, Charlotte Kristiane; Holm, Anders; Olsen, John Elmerdahl; Nielsen, Søren Saxmose; Nielsen, Jens Peter

2016-01-01

Oral treatment with antimicrobials is widely used in pig production for the control of gastrointestinal infections. Lawsonia intracellularis (LI) causes enteritis in pigs older than six weeks of age and is commonly treated with antimicrobials. The objective of this study was to evaluate the efficacy of three oral dosage regimens (5, 10 and 20mg/kg body weight) of oxytetracycline (OTC) in drinking water over a five-day period on diarrhoea, faecal shedding of LI and average daily weight gain (ADG). A randomised clinical trial was carried out in four Danish pig herds. In total, 539 animals from 37 batches of nursery pigs were included in the study. The dosage regimens were randomly allocated to each batch and initiated at presence of assumed LI-related diarrhoea. In general, all OTC doses used for the treatment of LI infection resulted in reduced diarrhoea and LI shedding after treatment. Treatment with a low dose of 5mg/kg OTC per kg body weight, however, tended to cause more watery faeces and resulted in higher odds of pigs shedding LI above detection level when compared to medium and high doses (with odds ratios of 5.5 and 8.4, respectively). No association was found between the dose of OTC and the ADG. In conclusion, a dose of 5mg OTC per kg body weight was adequate for reducing the high-level LI shedding associated with enteropathy, but a dose of 10mg OTC per kg body weight was necessary to obtain a maximum reduction in LI shedding. Copyright © 2015 Elsevier B.V. All rights reserved.

Dosimetric impact of prostate volume change between CT-based HDR brachytherapy fractions

International Nuclear Information System (INIS)

Kim, Yongbok; Hsu, I-C.; Lessard, Etienne; Vujic, Jasmina; Pouliot, Jean

2004-01-01

Purpose: The objective is to evaluate the prostate volume change and its dosimetric consequences after the insertion of catheters for high-dose-rate brachytherapy. Methods and Materials: For 13 consecutive patients, a spiral CT scan was acquired before each of the 2 fractions, separated on average by 20 hours. The coordinates of the catheters were obtained on 3 axial CT slices corresponding to apex, mid portion, and base portion of the prostate. A mathematical expansion model was used to evaluate the change of prostate volumes between the 2 fractions. It is based on the difference in the cube of the average distance between the centroid and catheter positions. The variation of implant dose-volume histograms between fractions was computed for plans produced by either inverse planning based on simulated annealing or geometric optimization. Results: The average magnitude of either increase or reduction in prostate volume was 7.8% (range, 2-17%). This volume change corresponds to an average prostate radius change of only 2.5% (range, 0.7-5.4%). For 5 patients, the prostate volume increased on average by 9% (range, 2-17%), whereas a reduction was observed for 8 patients by an average of 7% (range, 2-13%). More variation was observed at the prostate base than at mid or apex gland. The comparison of implant dose-volume histograms showed a small reduction of V100 receiving the prescription dose, with an average of 3.5% (range, 0.5-12%) and 2.2% (range, 1-6%) for inverse planning based on our simulated annealing and geometric optimization plans, respectively. Conclusion: Small volume change was observed between treatment fractions. This translates into small changes in dose delivered to the prostate volume

Feasibility of ultrasound-guided high intensity focused ultrasound ablating uterine fibroids with hyperintense on T2-weighted MR imaging

International Nuclear Information System (INIS)

Zhao, Wen-Peng; Chen, Jin-Yun; Zhang, Lian; Li, Quan; Qin, Juan

2013-01-01

Purpose: To retrospectively investigate whether uterine fibroids with hyperintense on pretreatment T2-weighted magnetic resonance imaging (MRI) could be treated with ultrasound-guided high intensity focused ultrasound (USgHIFU). Materials and methods: 282 patients with 282 symptomatic uterine fibroids who underwent USgHIFU treatment were retrospectively analyzed. Based on the signal intensity of T2-weighted MRI, uterine fibroids were classified as hypointense, isointense and hyperintense. Hyperintense fibroids were subjectively further subdivided into heterogeneous hyperintense, slightly homogeneous hyperintense and markedly homogeneous hyperintense based on the signal intensity of fibroid relative to myometrium and endometrium on T2-weighted MRI. Enhanced MRI was performed within one month after HIFU treatment. Non-perfused volume (NPV, indicative of successful ablation) ratio, treatment time, treatment efficiency, energy effect ratio and adverse events were recorded. Results: The median volume of uterine fibroids was 70.3 cm 3 (interquartile range, 41.1–132.5 cm 3 ). The average NPV ratio, defined as non-perfused volume divided by the fibroid volume after HIFU treatment, was 76.8 ± 19.0% (range, 0–100%) in the 282 patients. It was 86.3 ± 11.9% (range, 40.9–100.0%) in the group with hypointense fibroids, 77.1 ± 16.5% (range, 32.2–100.0%) in isointense fibroids, and 67.6 ± 23.9% (range, 0–100.0%) in hyperintense fibroids. The lowest NPV ratio, lowest treatment efficiency, more treatment time, more sonication energy and pain scores were observed in the slightly homogeneous hyperintense fibroids, and the NPV ratio was 55.8 ± 26.7% (range, 0–83.9%) in this subgroup. Conclusion: Based on our results, the heterogeneous and markedly homogeneous hyperintense fibroids were suitable for USgHIFU, and only the slightly homogeneous hyperintense fibroids should be excluded

76 FR 28998 - Implementation of Revised Passenger Weight Standards for Existing Passenger Vessels

Science.gov (United States)

2011-05-19

... Inspection prior to a change in the assumed average weight per person standard that will become effective in... several factors, including the total weight of people carried based on an Assumed Average Weight per... reason, the policy letter referred to in this notice provides supplemental guidance to the implementation...

Results of Long-term Measurement of 222Rn Volume Activity in Soil Air

International Nuclear Information System (INIS)

Holy, K.; Matos, M.; Boem, R.; Stanys, T.; Hola, O.; Polaskova, A.

1999-01-01

Radon in the soil air was continuously monitored for four years. The measured volume activities differ one from another even three times. On the basis of the measured data the annual and average daily courses of the 222 Rn volume activity were studied for individual months. In annual courses the winter and also summer maxima of the 222 Rn volume activity were found out. The study of the average daily courses revealed that the oscillation of the 222 Rn volume activity about its average value during a day is only a few percent. For dry summer months a linear relation was found out between the changes of the 222 Rn volume activity and the changes of the atmospheric pressure in their average daily courses (Authors)

Disc volume reduction with percutaneous nucleoplasty in an animal model.

Directory of Open Access Journals (Sweden)

Richard Kasch

Full Text Available STUDY DESIGN: We assessed volume following nucleoplasty disc decompression in lower lumbar spines from cadaveric pigs using 7.1Tesla magnetic resonance imaging (MRI. PURPOSE: To investigate coblation-induced volume reductions as a possible mechanism underlying nucleoplasty. METHODS: We assessed volume following nucleoplastic disc decompression in pig spines using 7.1-Tesla MRI. Volumetry was performed in lumbar discs of 21 postmortem pigs. A preoperative image data set was obtained, volume was determined, and either disc decompression or placebo therapy was performed in a randomized manner. Group 1 (nucleoplasty group was treated according to the usual nucleoplasty protocol with coblation current applied to 6 channels for 10 seconds each in an application field of 360°; in group 2 (placebo group the same procedure was performed but without coblation current. After the procedure, a second data set was generated and volumes calculated and matched with the preoperative measurements in a blinded manner. To analyze the effectiveness of nucleoplasty, volumes between treatment and placebo groups were compared. RESULTS: The average preoperative nucleus volume was 0.994 ml (SD: 0.298 ml. In the nucleoplasty group (n = 21 volume was reduced by an average of 0.087 ml (SD: 0.110 ml or 7.14%. In the placebo group (n = 21 volume was increased by an average of 0.075 ml (SD: 0.075 ml or 8.94%. The average nucleoplasty-induced volume reduction was 0.162 ml (SD: 0.124 ml or 16.08%. Volume reduction in lumbar discs was significant in favor of the nucleoplasty group (p<0.0001. CONCLUSIONS: Our study demonstrates that nucleoplasty has a volume-reducing effect on the lumbar nucleus pulposus in an animal model. Furthermore, we show the volume reduction to be a coblation effect of nucleoplasty in porcine discs.

Weight Distribution for Non-binary Cluster LDPC Code Ensemble

Science.gov (United States)

Nozaki, Takayuki; Maehara, Masaki; Kasai, Kenta; Sakaniwa, Kohichi

In this paper, we derive the average weight distributions for the irregular non-binary cluster low-density parity-check (LDPC) code ensembles. Moreover, we give the exponential growth rate of the average weight distribution in the limit of large code length. We show that there exist $(2,d_c)$-regular non-binary cluster LDPC code ensembles whose normalized typical minimum distances are strictly positive.

C-arm flat detector computed tomography parenchymal blood volume imaging: the nature of parenchymal blood volume parameter and the feasibility of parenchymal blood volume imaging in aneurysmal subarachnoid haemorrhage patients

Energy Technology Data Exchange (ETDEWEB)

Kamran, Mudassar; Byrne, James V. [University of Oxford, Nuffield Department of Surgical Sciences, Oxford (United Kingdom)

2015-09-15

C-arm flat detector computed tomography (FDCT) parenchymal blood volume (PBV) measurements allow assessment of cerebral haemodynamics in the neurointerventional suite. This paper explores the feasibility of C-arm computed tomography (CT) PBV imaging and the relationship between the C-arm CT PBV and the MR-PWI-derived cerebral blood volume (CBV) and cerebral blood flow (CBF) parameters in aneurysmal subarachnoid haemorrhage (SAH) patients developing delayed cerebral ischemia (DCI). Twenty-six patients with DCI following aneurysmal SAH underwent a research C-arm CT PBV scan using a biplane angiography system and contemporaneous MR-PWI scan as part of a prospective study. Quantitative whole-brain atlas-based volume-of-interest analysis in conjunction with Pearson correlation and Bland-Altman tests was performed to explore the agreement between C-arm CT PBV and MR-derived CBV and CBF measurements. All patients received medical management, while eight patients (31 %) underwent selective intra-arterial chemical angioplasty. Colour-coded C-arm CT PBV maps were 91 % sensitive and 100 % specific in detecting the perfusion abnormalities. C-arm CT rPBV demonstrated good agreement and strong correlation with both MR-rCBV and MR-rCBF measurements; the agreement and correlation were stronger for MR-rCBF relative to MR-rCBV and improved for C-arm CT PBV versus the geometric mean of MR-rCBV and MR-rCBF. Analysis of weighted means showed that the C-arm CT PBV has a preferential blood flow weighting (∼60 % blood flow and ∼40 % blood volume weighting). C-arm CT PBV imaging is feasible in DCI following aneurysmal SAH. PBV is a composite perfusion parameter incorporating both blood flow and blood volume weightings. That PBV has preferential (∼60 %) blood flow weighting is an important finding, which is of clinical significance when interpreting the C-arm CT PBV maps, particularly in the setting of acute brain ischemia. (orig.)

C-arm flat detector computed tomography parenchymal blood volume imaging: the nature of parenchymal blood volume parameter and the feasibility of parenchymal blood volume imaging in aneurysmal subarachnoid haemorrhage patients

International Nuclear Information System (INIS)

Kamran, Mudassar; Byrne, James V.

2015-01-01

C-arm flat detector computed tomography (FDCT) parenchymal blood volume (PBV) measurements allow assessment of cerebral haemodynamics in the neurointerventional suite. This paper explores the feasibility of C-arm computed tomography (CT) PBV imaging and the relationship between the C-arm CT PBV and the MR-PWI-derived cerebral blood volume (CBV) and cerebral blood flow (CBF) parameters in aneurysmal subarachnoid haemorrhage (SAH) patients developing delayed cerebral ischemia (DCI). Twenty-six patients with DCI following aneurysmal SAH underwent a research C-arm CT PBV scan using a biplane angiography system and contemporaneous MR-PWI scan as part of a prospective study. Quantitative whole-brain atlas-based volume-of-interest analysis in conjunction with Pearson correlation and Bland-Altman tests was performed to explore the agreement between C-arm CT PBV and MR-derived CBV and CBF measurements. All patients received medical management, while eight patients (31 %) underwent selective intra-arterial chemical angioplasty. Colour-coded C-arm CT PBV maps were 91 % sensitive and 100 % specific in detecting the perfusion abnormalities. C-arm CT rPBV demonstrated good agreement and strong correlation with both MR-rCBV and MR-rCBF measurements; the agreement and correlation were stronger for MR-rCBF relative to MR-rCBV and improved for C-arm CT PBV versus the geometric mean of MR-rCBV and MR-rCBF. Analysis of weighted means showed that the C-arm CT PBV has a preferential blood flow weighting (∼60 % blood flow and ∼40 % blood volume weighting). C-arm CT PBV imaging is feasible in DCI following aneurysmal SAH. PBV is a composite perfusion parameter incorporating both blood flow and blood volume weightings. That PBV has preferential (∼60 %) blood flow weighting is an important finding, which is of clinical significance when interpreting the C-arm CT PBV maps, particularly in the setting of acute brain ischemia. (orig.)

Changes in the air cell volume of artificially incubated ostrich eggs ...

African Journals Online (AJOL)

A total of 2160 images of candled, incubated ostrich eggs were digitized to determine the percentage of egg volume occupied by the air cell at different stages of incubation. The air cell on average occupied 2.5% of the volume of fresh eggs. For eggs that hatched successfully, this volume increased to an average of 24.4% ...

Cluster analysis of behavioural weight management strategies and associations with weight change in young women: a longitudinal analysis.

Science.gov (United States)

Madigan, C D; Daley, A J; Kabir, E; Aveyard, P; Brown, W

2015-11-01

Maintaining a healthy weight is important for the prevention of many chronic diseases. Little is known about the strategies used by young women to manage their weight, or the effectiveness of these in preventing weight gain. We aimed to identify clusters of weight control strategies used by women and to determine the average annual weight change among women in each cluster from 2000 to 2009. Latent cluster analysis of weight control strategies reported by 8125 participants in the Australian Longitudinal Study of Women's Health. Analyses were performed in March-November 2014. Weight control strategies were used by 79% of the women, and four unique clusters were found. The largest cluster group (39.7%) was named dieters as 90% had been on a diet in the past year, and half of these women had lost 5 kg on purpose. Women cut down on size of meals, fats and sugars and took part in vigorous physical activity. Additionally 20% had used a commercial programme. The next largest cluster (30.2%) was the healthy living group who followed the public health messages of 'eat less and move more'. The do nothing group (20%) did not actively control their weight whereas the perpetual dieters group (10.7%) used all strategies, including unhealthy behaviours. On average women gained 700 g per year (over 9 years); however, the perpetual dieters group gained significantly more weight (210 g) than the do nothing group (Phealth guidelines on health eating and physical activity.

Multiple-level defect species evaluation from average carrier decay

Science.gov (United States)

Debuf, Didier

2003-10-01

An expression for the average decay is determined by solving the the carrier continuity equations, which include terms for multiple defect recombination. This expression is the decay measured by techniques such as the contactless photoconductance decay method, which determines the average or volume integrated decay. Implicit in the above is the requirement for good surface passivation such that only bulk properties are observed. A proposed experimental configuration is given to achieve the intended goal of an assessment of the type of defect in an n-type Czochralski-grown silicon semiconductor with an unusually high relative lifetime. The high lifetime is explained in terms of a ground excited state multiple-level defect system. Also, minority carrier trapping is investigated.

Determinants of weight regain after bariatric surgery.

Science.gov (United States)

Bastos, Emanuelle Cristina Lins; Barbosa, Emília Maria Wanderley Gusmão; Soriano, Graziele Moreira Silva; dos Santos, Ewerton Amorim; Vasconcelos, Sandra Mary Lima

2013-01-01

Bariatric surgery leads to an average loss of 60-75% of excess body weight with maximum weight loss in the period between 18 and 24 months postoperatively. However, several studies show that weight is regained from two years of operation. To identify the determinants of weight regain in post-bariatric surgery users. Prospective cross-sectional study with 64 patients who underwent bariatric surgery with postoperative time > 2 years valued at significant weight regain. The variables analyzed were age, sex, education, socioeconomic status, work activity related to food, time after surgery, BMI, percentage of excess weight loss, weight gain, attendance monitoring nutrition, lifestyle, eating habits, self-perception of appetite, daily use of nutritional supplements and quality of life. There were 57 (89%) women and 7 (11%) men, aged 41.76 ± 7.93 years and mean postoperative period of 53.4 ± 18.4 months. The average weight and BMI were respectively 127.48 ± 24.2 kg and 49.56 ± 6.7 kg/m2 at surgery. The minimum weight and BMI were achieved 73.0 ± 18.6 kg and 28.3 ± 5.5 kg/m2, reached in 23.7 ± 12 months postoperatively. Regained significant weight occurred in 18 (28.1%) cases. The mean postoperative period of 66 ± 8.3 months and work activities related to food showed statistical significance (p=000 and p=0.003) for the regained weight. Bariatric surgery promotes adequate reduction of excess body weight, with significant weight regain observed after five years; post-operative time and work activity related to eating out as determining factors for the occurrence of weight regain.

40 CFR 80.825 - How is the refinery or importer annual average toxics value determined?

Science.gov (United States)

2010-07-01

... volume of applicable gasoline produced or imported in batch i. Ti = The toxics value of batch i. n = The number of batches of gasoline produced or imported during the averaging period. i = Individual batch of gasoline produced or imported during the averaging period. (b) The calculation specified in paragraph (a...

A core-monitoring based methodology for predictions of graphite weight loss in AGR moderator bricks

Energy Technology Data Exchange (ETDEWEB)

McNally, K., E-mail: kevin.mcnally@hsl.gsi.gov.uk [Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN (United Kingdom); Warren, N. [Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN (United Kingdom); Fahad, M.; Hall, G.; Marsden, B.J. [Nuclear Graphite Research Group, School of MACE, University of Manchester, Manchester M13 9PL (United Kingdom)

2017-04-01

Highlights: • A statistically-based methodology for estimating graphite density is presented. • Graphite shrinkage is accounted for using a finite element model. • Differences in weight loss forecasts were found when compared to the existing model. - Abstract: Physically based models, resolved using the finite element (FE) method are often used to model changes in dimensions and the associated stress fields of graphite moderator bricks within a reactor. These models require inputs that describe the loading conditions (temperature, fluence and weight loss ‘field variables’), and coded relationships describing the behaviour of graphite under these conditions. The weight loss field variables are calculated using a reactor chemistry/physics code FEAT DIFFUSE. In this work the authors consider an alternative data source of weight loss: that from a longitudinal dataset of density measurements made on small samples trepanned from operating reactors during statutory outages. A nonlinear mixed-effect model is presented for modelling the age and depth-related trends in density. A correction that accounts for irradiation-induced dimensional changes (axial and radial shrinkage) is subsequently applied. The authors compare weight loss forecasts made using FEAT DIFFUSE with those based on an alternative statistical model for a layer four moderator brick for the Hinkley Point B, Reactor 3. The authors compare the two approaches for the weight loss distribution through the brick with a particular focus on the interstitial keyway, and for the average (over the volume of the brick) weight loss.

Fluctuations of trading volume in a stock market

Science.gov (United States)

Hong, Byoung Hee; Lee, Kyoung Eun; Hwang, Jun Kyung; Lee, Jae Woo

2009-03-01

We consider the probability distribution function of the trading volume and the volume changes in the Korean stock market. The probability distribution function of the trading volume shows double peaks and follows a power law, P(V/)∼( at the tail part of the distribution with α=4.15(4) for the KOSPI (Korea composite Stock Price Index) and α=4.22(2) for the KOSDAQ (Korea Securities Dealers Automated Quotations), where V is the trading volume and is the monthly average value of the trading volume. The second peaks originate from the increasing trends of the average volume. The probability distribution function of the volume changes also follows a power law, P(Vr)∼Vr-β, where Vr=V(t)-V(t-T) and T is a time lag. The exponents β depend on the time lag T. We observe that the exponents β for the KOSDAQ are larger than those for the KOSPI.

Physical Activity Patterns in Normal-Weight and Overweight/Obese Pregnant Women.

Directory of Open Access Journals (Sweden)

Elisabetta Bacchi

Full Text Available The aims of the present study were to assess the volume of physical activity (PA throughout pregnancy in normal-weight vs overweight/obese women, and to investigate which factors may predict compliance to PA recommendations in these women throughout gestation. In 236 pregnant women, 177 normal-weight and 59 overweight/obese (median[IQR] BMI 21.2[19.9-22.8] vs 26.5[25.5-29.0] kg/m2, respectively, medical history, anthropometry and clinical data, including glucose tolerance, were recorded. In addition, pre-pregnancy PA was estimated by the Kaiser questionnaire, while total, walking and fitness/sport PA during pregnancy were assessed by the Physical Activity Scale for the Elderly (PASE modified questionnaire, at 14-16, 24-28 and 30-32 weeks of gestation. PA volume was very low in the first trimester of pregnancy in both groups of women. However, it increased in the second and third trimester in normal-weight, but not in overweight/obese subjects. Higher pre-pregnancy PA was a statistically significant predictor of being physically active (>150 minutes of PA per week during all trimesters of gestation. In conclusion, physical activity volume is low in pregnant women, especially in overweight/obese subjects. PA volume increases during pregnancy only in normal-weight women. Pre-pregnancy PA is an independent predictor of achieving a PA volume of at least 150 min per week during pregnancy.

Development of planning level transportation safety tools using Geographically Weighted Poisson Regression.

Science.gov (United States)

Hadayeghi, Alireza; Shalaby, Amer S; Persaud, Bhagwant N

2010-03-01

A common technique used for the calibration of collision prediction models is the Generalized Linear Modeling (GLM) procedure with the assumption of Negative Binomial or Poisson error distribution. In this technique, fixed coefficients that represent the average relationship between the dependent variable and each explanatory variable are estimated. However, the stationary relationship assumed may hide some important spatial factors of the number of collisions at a particular traffic analysis zone. Consequently, the accuracy of such models for explaining the relationship between the dependent variable and the explanatory variables may be suspected since collision frequency is likely influenced by many spatially defined factors such as land use, demographic characteristics, and traffic volume patterns. The primary objective of this study is to investigate the spatial variations in the relationship between the number of zonal collisions and potential transportation planning predictors, using the Geographically Weighted Poisson Regression modeling technique. The secondary objective is to build on knowledge comparing the accuracy of Geographically Weighted Poisson Regression models to that of Generalized Linear Models. The results show that the Geographically Weighted Poisson Regression models are useful for capturing spatially dependent relationships and generally perform better than the conventional Generalized Linear Models. Copyright 2009 Elsevier Ltd. All rights reserved.

Relationship between partial and average atomic volumes of components in Au-Ni alloys%Au-Ni合金中组元的平均原子体积和偏摩尔体积的关系

Institute of Scientific and Technical Information of China (English)

谢佑卿

2011-01-01

在系统合金科学框架中建立有关无序合金的平均摩尔性质(体积和势能)的函数.通过对这些函数进行推导,可以得到平均摩尔体积函数、偏摩尔体积函数及派生出与成分相关的函数.在组元的偏摩尔性质和平均摩尔性质之间的普适方程、差分方程、在偏摩尔性质和平均摩尔性质之间不同参数的约束方程和普适的Gibbs-Duhem公式.可以证明从合金平均摩尔性质的不同函数计算的偏摩尔性质是相等的,但总体来说偏摩尔性质不等于给定组元的平均摩尔性质,即偏摩尔性质不能代表相应组元的摩尔性质.通过计算Au-Ni系中组元的偏摩尔体积和平均原子体积以及合金的平均原子体积,证明所建立的公式和函数的正确性.%In the framework of systematic science of alloys,the average molar property (volume and potential energy) functions of disordered alloys were established.From these functions,the average molar property functions,partial molar property functions,derivative functions with respect to composition,general equation of relationship between partial and average molar properties of components,difference equation and constraining equation of different values between partial and average molar properties,as well as general Gibbs-Duhem formula were derived.It was proved that the partial molar properties calculated from various combinative functions of average molar properties of alloys are equal,but in general,the partial molar properties are not equal to the average molar properties of a given component.This means that the partial molar properties cannot represent the corresponding properties of the component.All the equations and functions established in this work were proved to be correct by calculating the results of partial and average atomic volumes of components as well as average atomic volumes of alloys in the Au-Ni system.

Phantom study of PET/CT guided delineation of radiation therapy volume

International Nuclear Information System (INIS)

Lin Lin; Zheng Rong; Wang Yibin; Geng Jianhua; Wu Ning; Zhao Ping

2012-01-01

Objective: To propose a model-based method for calculating the threshold in GTV determination by 18 F-FDG PET in a phantom study. Methods: A phantom was constructed of a 9 L cylindrical tank.Glass spheres with volumes ranging from 0.5 to 16 ml (0.5, 1, 2, 4, 8 and 16 ml) were suspended within the tank. The six spheres were filled with an identical concentration of FDG (203.5 MBq/L) and suspended within 3 different background baths of FDG (6.179, 16.021, 0 MBq/L) solutions, creating 3 target-to-background ratios of 32.96 : 1, 12.69 : 1 and target to zero background. A linear regressive function was constructed which represented the relationship between the threshold and the average activity concentration of the target. A 40% of maximum intensity threshold and the linear regressive function method were applied to define the spheres filled with 18 F-FDG. The volume differences between the two methods and the true volumes of the spheres were compared with t-test. Results: The linear regressive function model was derived as:threshold =(mean target concentration + 2.6227)/1.9752. The results indicated that a smaller deviation occurred when the function was utilized to estimate the volumes of the phantoms as compared to the 40% of maximum intensity threshold method, but there were no significant differences between them (t=0.306, P>0.05). The effect of the linear regressive function on volume was such that when the phantom sphere volumes were ≥ 1 ml, the average deviation between the defined volumes and the true volumes of phantoms was 1.01%; but when the phantom sphere volume was 0.5 ml, the average deviation was 9.53%. When the 40% of maximum intensity threshold method was applied to define the phantom spheres of volume ≥2 ml, the average deviation between the defined volumes and the true volumes of phantoms was -4.62%; but, the average deviation of that was 19.9% when the volumes of spheres were 0.5 and 1 ml. When the linear regressive function was applied to

College Freshman Stress and Weight Change: Differences by Gender

Science.gov (United States)

Economos, Christina D.; Hildebrandt, M. Lise; Hyatt, Raymond R.

2008-01-01

Objectives: To examine how stress and health-related behaviors affect freshman weight change by gender. Methods: Three hundred ninety-six freshmen completed a 40-item health behavior survey and height and weight were collected at baseline and follow-up. Results: Average weight change was 5.04 lbs for males, 5.49 lbs for females. Weight gain was…

Model averaging, optimal inference and habit formation

Directory of Open Access Journals (Sweden)

Thomas H B FitzGerald

2014-06-01

Full Text Available Postulating that the brain performs approximate Bayesian inference generates principled and empirically testable models of neuronal function – the subject of much current interest in neuroscience and related disciplines. Current formulations address inference and learning under some assumed and particular model. In reality, organisms are often faced with an additional challenge – that of determining which model or models of their environment are the best for guiding behaviour. Bayesian model averaging – which says that an agent should weight the predictions of different models according to their evidence – provides a principled way to solve this problem. Importantly, because model evidence is determined by both the accuracy and complexity of the model, optimal inference requires that these be traded off against one another. This means an agent’s behaviour should show an equivalent balance. We hypothesise that Bayesian model averaging plays an important role in cognition, given that it is both optimal and realisable within a plausible neuronal architecture. We outline model averaging and how it might be implemented, and then explore a number of implications for brain and behaviour. In particular, we propose that model averaging can explain a number of apparently suboptimal phenomena within the framework of approximate (bounded Bayesian inference, focussing particularly upon the relationship between goal-directed and habitual behaviour.

Composite indicators for security of energy supply using ordered weighted averaging

International Nuclear Information System (INIS)

Costescu Badea, Anca; Rocco S, Claudio M.; Tarantola, Stefano; Bolado, Ricardo

2011-01-01

In this paper we propose to use an aggregation rule derived from the Group Decision Theory, and based on the ranks of a set of individual indicators, for building a family of composite indicators for the security of energy supply. This family of composite indicators depends on a parameter associated with the risk-averse level of the decision maker, which can hence vary continuously from risk-prone to risk-averse. It represents a valuable and objective instrument to evaluate the degree of security of energy supply of different countries without entering into controversial matters related to the choice of the weights. This methodology can be used to aggregate either ranks or normalized values of the individual indicators. We apply it to a set of individual indicators, accounting for different dimensions of the security of supply and derived from the outputs of an energy system model. We study the evolution in time of the countries' performances, as well as the propagation of the uncertainties associated with the individual indicators to the composite. We also studied the robustness of such composite indicators with respect to the risk-averse level.

Weighted-Average Least Squares Prediction

NARCIS (Netherlands)

Magnus, Jan R.; Wang, Wendun; Zhang, Xinyu

2016-01-01

Prediction under model uncertainty is an important and difficult issue. Traditional prediction methods (such as pretesting) are based on model selection followed by prediction in the selected model, but the reported prediction and the reported prediction variance ignore the uncertainty from the

A low cost, light weight cenosphere–aluminium composite for brake ...

Indian Academy of Sciences (India)

. Home; Journals; Bulletin of Materials Science; Volume 39; Issue 1. A low cost, light weight cenosphere–aluminium composite for brake disc application. V Saravanan P R Thyla S R Balakrishnan. Volume 39 Issue 1 February 2016 pp 299-305 ...

Effects of dietary protein levels on length-weight relationships and ...

African Journals Online (AJOL)

Feeding trial involving different protein levels on length–weight relationships and condition factor of Clarias gariepinus was conducted in floating hapa system. Fingerlings (average weight, 4.50± 0.01g and average length, 8.0±0.2 cm) were randomly stocked at 20 fish/1m3. Five diets with crude protein: 40.0, 42.5, 45.0, 47.5 ...

Development of Automatic Visceral Fat Volume Calculation Software for CT Volume Data

Directory of Open Access Journals (Sweden)

Mitsutaka Nemoto

2014-01-01

Full Text Available Objective. To develop automatic visceral fat volume calculation software for computed tomography (CT volume data and to evaluate its feasibility. Methods. A total of 24 sets of whole-body CT volume data and anthropometric measurements were obtained, with three sets for each of four BMI categories (under 20, 20 to 25, 25 to 30, and over 30 in both sexes. True visceral fat volumes were defined on the basis of manual segmentation of the whole-body CT volume data by an experienced radiologist. Software to automatically calculate visceral fat volumes was developed using a region segmentation technique based on morphological analysis with CT value threshold. Automatically calculated visceral fat volumes were evaluated in terms of the correlation coefficient with the true volumes and the error relative to the true volume. Results. Automatic visceral fat volume calculation results of all 24 data sets were obtained successfully and the average calculation time was 252.7 seconds/case. The correlation coefficients between the true visceral fat volume and the automatically calculated visceral fat volume were over 0.999. Conclusions. The newly developed software is feasible for calculating visceral fat volumes in a reasonable time and was proved to have high accuracy.

Growth and relationship of live weight to body measurements in semi-domesticated reindeer (Rangifer tarandus tarandus L.

Directory of Open Access Journals (Sweden)

Mauri Nieminen

1990-09-01

Full Text Available Estimation of live weight from measurements of body dimensions is useful in many management activities with domestic animals. In present study live weight was measured from 2932 female and 1037 male semi-domesticated reindeer (Rangifer tarandus tarandus L. during different seasons in 1969-85. The age of reindeer varied between 1 day and 14 yrs. Back length (along back from second spinous process to base of tail and chest girth (just behind front legs were taken also from 1490 female and 510 male reindeer. The growth of reindeer from birth to adulthood was cumulative consisting of a rapid weight accretion during summers followed by a weight loss or stasis during winters. The mathematical analyses of the growth based on exponential solutions gave average values for growth of female and male reindeer. Body weight of females increased until the age of 4.5 yrs and that of males until the age of 5.5 yrs. During winter and spring body weight of hinds decreased 10 to 15 kg and that of stags 30 to 50 kg in different age groups. Significant linear regressions were found between live weight and back length (r = 0.809 and 0.892, live weight and chest girth (r = 0.860 and 0.872 and live weight and combined body measure (back length + chest girth (r = 0.877 and 0.941 and live weight and body volume (r = 0.905 and 0.954, respectively in female and male reindeer. Exponential regressions gave, however, the best estimations of live weight with combined body measure.

A theoretical approach to the problem of dose-volume constraint estimation and their impact on the dose-volume histogram selection

International Nuclear Information System (INIS)

Schinkel, Colleen; Stavrev, Pavel; Stavreva, Nadia; Fallone, B. Gino

2006-01-01

This paper outlines a theoretical approach to the problem of estimating and choosing dose-volume constraints. Following this approach, a method of choosing dose-volume constraints based on biological criteria is proposed. This method is called ''reverse normal tissue complication probability (NTCP) mapping into dose-volume space'' and may be used as a general guidance to the problem of dose-volume constraint estimation. Dose-volume histograms (DVHs) are randomly simulated, and those resulting in clinically acceptable levels of complication, such as NTCP of 5±0.5%, are selected and averaged producing a mean DVH that is proven to result in the same level of NTCP. The points from the averaged DVH are proposed to serve as physical dose-volume constraints. The population-based critical volume and Lyman NTCP models with parameter sets taken from literature sources were used for the NTCP estimation. The impact of the prescribed value of the maximum dose to the organ, D max , on the averaged DVH and the dose-volume constraint points is investigated. Constraint points for 16 organs are calculated. The impact of the number of constraints to be fulfilled based on the likelihood that a DVH satisfying them will result in an acceptable NTCP is also investigated. It is theoretically proven that the radiation treatment optimization based on physical objective functions can sufficiently well restrict the dose to the organs at risk, resulting in sufficiently low NTCP values through the employment of several appropriate dose-volume constraints. At the same time, the pure physical approach to optimization is self-restrictive due to the preassignment of acceptable NTCP levels thus excluding possible better solutions to the problem

The effect of performance-volume limit on the DRG based acute care hospital financing in Hungary.

Science.gov (United States)

Endrei, Dóra; Zemplényi, Antal; Molics, Bálint; Agoston, István; Boncz, Imre

2014-04-01

The aim of our paper is to analyse the effect of the so-called performance volume limit (PVL) financing method on acute hospital care. The data were derived from the nationwide administrative dataset of the National Health Insurance Fund Administration (OEP) covering the period 2003-2008. We analysed the trends in the DRG cost-weights, number of cases, case-mix, and average length of stay. We calculated the average annual reimbursement rate per DRG cost-weight with and without the application of PVL degression according to the hospital type and medical professions. Our results showed that although the national case mix (i.e., the sum of all of the DRG cost-weights produced in one year) did not change between 2003-2006, the trend of the annual number of cases increased, and the average length of stay decreased. During 2007-2008, a significant decline was found in each indicator. The introduction of the PVL resulted in a health insurance budget saving of 1.9% in 2004, 2.6% in 2005, 3.4% in 2006, 5.6% in 2007, and 3.2% in 2008. We found the lowest reimbursement rate per DRG cost-weight at the university medical schools (HUF 138,200 or € 550) and children's hospitals (HUF 132,547 or € 528), whereas the highest was at the county hospitals (HUF 143,451 or € 571) and city hospitals (HUF 142, 082 or € 565). The implementation of the PVL reduced the acute care hospital activity and reimbursement. The effect of the PVL was different on the different types of hospitals, and it had a serious disadvantageous effect on the university medical schools and children's hospitals. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Haptic biofeedback for improving compliance with lower-extremity partial weight bearing.

Science.gov (United States)

Fu, Michael C; DeLuke, Levi; Buerba, Rafael A; Fan, Richard E; Zheng, Ying Jean; Leslie, Michael P; Baumgaertner, Michael R; Grauer, Jonathan N

2014-11-01

After lower-extremity orthopedic trauma and surgery, patients are often advised to restrict weight bearing on the affected limb. Conventional training methods are not effective at enabling patients to comply with recommendations for partial weight bearing. The current study assessed a novel method of using real-time haptic (vibratory/vibrotactile) biofeedback to improve compliance with instructions for partial weight bearing. Thirty healthy, asymptomatic participants were randomized into 1 of 3 groups: verbal instruction, bathroom scale training, and haptic biofeedback. Participants were instructed to restrict lower-extremity weight bearing in a walking boot with crutches to 25 lb, with an acceptable range of 15 to 35 lb. A custom weight bearing sensor and biofeedback system was attached to all participants, but only those in the haptic biofeedback group were given a vibrotactile signal if they exceeded the acceptable range. Weight bearing in all groups was measured with a separate validated commercial system. The verbal instruction group bore an average of 60.3±30.5 lb (mean±standard deviation). The bathroom scale group averaged 43.8±17.2 lb, whereas the haptic biofeedback group averaged 22.4±9.1 lb (Phaptic biofeedback group averaged 14.5±6.3% (Phaptic biofeedback to improve compliance with lower-extremity partial weight bearing, haptic biofeedback was superior to conventional physical therapy methods. Further studies in patients with clinical orthopedic trauma are warranted. Copyright 2014, SLACK Incorporated.

Volume-Targeted Ventilation in the Neonate: Benchmarking Ventilators on an Active Lung Model.

Science.gov (United States)

Krieger, Tobias J; Wald, Martin

2017-03-01

Mechanically ventilated neonates have been observed to receive substantially different ventilation after switching ventilator models, despite identical ventilator settings. This study aims at establishing the range of output variability among 10 neonatal ventilators under various breathing conditions. Relative benchmarking test of 10 neonatal ventilators on an active neonatal lung model. Neonatal ICU. Ten current neonatal ventilators. Ventilators were set identically to flow-triggered, synchronized, volume-targeted, pressure-controlled, continuous mandatory ventilation and connected to a neonatal lung model. The latter was configured to simulate three patients (500, 1,500, and 3,500 g) in three breathing modes each (passive breathing, constant active breathing, and variable active breathing). Averaged across all weight conditions, the included ventilators delivered between 86% and 110% of the target tidal volume in the passive mode, between 88% and 126% during constant active breathing, and between 86% and 120% under variable active breathing. The largest relative deviation occurred during the 500 g constant active condition, where the highest output machine produced 147% of the tidal volume of the lowest output machine. All machines deviate significantly in volume output and ventilation regulation. These differences depend on ventilation type, respiratory force, and patient behavior, preventing the creation of a simple conversion table between ventilator models. Universal neonatal tidal volume targets for mechanical ventilation cannot be transferred from one ventilator to another without considering necessary adjustments.

DESIGN OF MINIMUM-WEIGHT DIFFUSION BATTERIES

Science.gov (United States)

Until recently, the measurement of particle sizes in aerosols was largely a laboratory exercise. Currently, however, particulates in the atmosphere and in the industrial exhaust gases are being monitored extensively in the field. While the weight and volume of laboratory apparatu...

Lung protection: an intervention for tidal volume reduction in a teaching intensive care unit

Science.gov (United States)

Briva, Arturo; Gaiero, Cristina

2016-01-01

Objective To determine the effect of feedback and education regarding the use of predicted body weight to adjust tidal volume in a lung-protective mechanical ventilation strategy. Methods The study was performed from October 2014 to November 2015 (12 months) in a single university polyvalent intensive care unit. We developed a combined intervention (education and feedback), placing particular attention on the importance of adjusting tidal volumes to predicted body weight bedside. In parallel, predicted body weight was estimated from knee height and included in clinical charts. Results One hundred fifty-nine patients were included. Predicted body weight assessed by knee height instead of visual evaluation revealed that the delivered tidal volume was significantly higher than predicted. After the inclusion of predicted body weight, we observed a sustained reduction in delivered tidal volume from a mean (standard error) of 8.97 ± 0.32 to 7.49 ± 0.19mL/kg (p < 0.002). Furthermore, the protocol adherence was subsequently sustained for 12 months (delivered tidal volume 7.49 ± 0.54 versus 7.62 ± 0.20mL/kg; p = 0.103). Conclusion The lack of a reliable method to estimate the predicted body weight is a significant impairment for the application of a worldwide standard of care during mechanical ventilation. A combined intervention based on education and repeated feedbacks promoted sustained tidal volume education during the study period (12 months). PMID:27925055

Implementation and Effectiveness of a Psychosocial Weight Management Program for Individuals with Schizophrenia

Science.gov (United States)

Niv, Noosha; Cohen, Amy N.; Hamilton, Alison; Reist, Christopher; Young, Alexander S.

2013-01-01

The objective of this study was to examine the effectiveness of a weight loss program for individuals with schizophrenia in usual care. The study included 146 adults with schizophrenia from two mental health clinics of the Department of Veterans Affairs. The 109 individuals who were overweight or obese were offered a 16-week, psychosocial, weight management program. Weight and BMI were assessed at baseline, 1 year later and at each treatment session. Only 51% of those who were overweight or obese chose to enroll in the weight management program. Participants attended an average of 6.7 treatment sessions, lost an average of 2.4 pounds and had an average BMI decrease of 0.3. There was no significant change in weight or BMI compared to the control group. Intervention strategies that both improve utilization and yield greater weight loss need to be developed. PMID:22430566

The application value of diffusion-weighted magnetic resonance imaging in gross tumor volume delineation of esophageal squamous cell carcinoma

International Nuclear Information System (INIS)

Hou Dongliang; Shi Gaofeng; Gao Xianshu

2012-01-01

Objective: To analyze the application value of diffusion-weighted magnetic resonance imaging (DWMRI) in gross tumor volume (GTV) delineation of esophageal squamous cell carcinoma (SCC). Methods: Twenty-nine patients with esophageal SCC treated with radical surgery were analyzed. Routine CT scan, MRI T 2 -weighted and DWMRI were employed before surgery; diffusion-sensitive gradient b-values were taken 400, 600 and 800 s/mm 2 . GTVs were delineated using CT, MRI T 2 -weighted images and DWMRI under different b-value images. The length of GTVs measured under different images was compared with the pathological length and confirm the most accurate imaging condition. Use radiotherapy planning system to fuse DWMRI images and CT images to investigate the possibility of delineate GTVs on fused images. Results: The difference of GTV length value between CT, T 2 WI images and specimen was 3.36 mm and 2.84 mm. When b =400,600 and 800 s/mm 2 , the difference between GTV length value on the DWMRI images and on specimen was 0.47 mm, -0.47 mm and - 1.53 mm; the correlation coefficient of the measuring esophageal lengths on DWMRI images and the pathological lengths was 0.928, 0.927 and 0.938. DWMRI images and CT images could fuse accurately on radiotherapy planning system. GTV margin could.show clearly on fused images. Conclusions: DWMRI images can display the esophageal carcinoma lengths and margin accurately. When DWMRI images fused with CT images, GTV margin could show clearly,it can be used to delineate GTV accurately. (authors)

Time series analysis of brain regional volume by MR image

International Nuclear Information System (INIS)

Tanaka, Mika; Tarusawa, Ayaka; Nihei, Mitsuyo; Fukami, Tadanori; Yuasa, Tetsuya; Wu, Jin; Ishiwata, Kiichi; Ishii, Kenji

2010-01-01

The present study proposed a methodology of time series analysis of volumes of frontal, parietal, temporal and occipital lobes and cerebellum because such volumetric reports along the process of individual's aging have been scarcely presented. Subjects analyzed were brain images of 2 healthy males and 18 females of av. age of 69.0 y, of which T1-weighted 3D SPGR (spoiled gradient recalled in the steady state) acquisitions with a GE SIGNA EXCITE HD 1.5T machine were conducted for 4 times in the time series of 42-50 months. The image size was 256 x 256 x (86-124) voxels with digitization level 16 bits. As the template for the regions, the standard gray matter atlas (icbn452 a tlas p robability g ray) and its labeled one (icbn.Labels), provided by UCLA Laboratory of Neuro Imaging, were used for individual's standardization. Segmentation, normalization and coregistration were performed with the MR imaging software SPM8 (Statistic Parametric Mapping 8). Volumes of regions were calculated as their voxel ratio to the whole brain voxel in percent. It was found that the regional volumes decreased with aging in all above lobes examined and cerebellum in average percent per year of -0.11, -0.07, -0.04, -0.02, and -0.03, respectively. The procedure for calculation of the regional volumes, which has been manually operated hitherto, can be automatically conducted for the individual brain using the standard atlases above. (T.T.)

Characterization of Volume F Trash from the Three FY11 STS Missions: Trash Weights and Categorization and Microbial Characterization

Science.gov (United States)

Strayer, Richard F.; Hummerick, Mary E.; Richards, Jeffrey T.; McCoy, LaShelle E.; Roberts, Michael S.; Wheller, Raymond M.

2011-01-01

The project reported here provides microbial characterization support to the Waste Management Systems (WMS) element of NASA's Life Support and Habitation Systems (LSHS) program. Conventional microbiological methods were used to detect and enumerate microorganisms in STS Volume F Compartment trash for three shuttle missions: STS 133, 134, and 135. This trash was usually made available within 2 days of landing at KSC. The Volume F bag was weighed, opened and the contents were cataloged and placed into categories: personal hygiene items - inclUding EVA maximum absorbent garments (MAGs) and Elbow packs (daily toilet wipes, etc), drink containers, food waste (and containers), office waste (paper), and packaging materials - plastic film and duct tape. The average wet trash generation rate for the three STS missions was 0.362 % 0.157 kgwet crew 1 d-1 . This was considerably lower and more variable than the average rate for 4 STS missions reported for FY10. Trash subtotals by category: personal hygiene wastes, 56%; drink items, 11 %; food wastes, 18%; office waste, 3%; and plastic film, 12%. These wastes have an abundance of easily biodegraded compounds that can support the growth of microorganisms. Microbial characterization of trash showed that large numbers of bacteria and fungi have taken advantage of this readily available nutrient source to proliferate. Exterior and interior surfaces of plastic film bags containing trash were sampled and counts of cultivatable microbes were generally low and mostly occurred on trash bundles within the exterior trash bags. Personal hygiene wastes, drink containers, and food wastes and packaging all contained high levels of, mostly, aerobic heterotrophic bacteria and lower levels of yeasts and molds. Isolates from plate count media were obtained and identified .and were mostly aerobic heterotrophs with some facultative anaerobes. These are usually considered common environmental isolates on Earth. However, several pathogens were also

Optimal bounds and extremal trajectories for time averages in dynamical systems

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Tobasco, Ian; Goluskin, David; Doering, Charles

2017-11-01

For systems governed by differential equations it is natural to seek extremal solution trajectories, maximizing or minimizing the long-time average of a given quantity of interest. A priori bounds on optima can be proved by constructing auxiliary functions satisfying certain point-wise inequalities, the verification of which does not require solving the underlying equations. We prove that for any bounded autonomous ODE, the problems of finding extremal trajectories on the one hand and optimal auxiliary functions on the other are strongly dual in the sense of convex duality. As a result, auxiliary functions provide arbitrarily sharp bounds on optimal time averages. Furthermore, nearly optimal auxiliary functions provide volumes in phase space where maximal and nearly maximal trajectories must lie. For polynomial systems, such functions can be constructed by semidefinite programming. We illustrate these ideas using the Lorenz system, producing explicit volumes in phase space where extremal trajectories are guaranteed to reside. Supported by NSF Award DMS-1515161, Van Loo Postdoctoral Fellowships, and the John Simon Guggenheim Foundation.

Effects of Harvesting Systems and Bole Moisture Loss on Weight Scaling of Douglas-Fir Sawlogs (Pseudotsuga Menziesii var. glauca Franco

Directory of Open Access Journals (Sweden)

Jarred D. Saralecos

2014-09-01

Full Text Available Characterizing the moisture loss from felled trees is essential for determining weight-to-volume (W-V relationships in softwood sawlogs. Several factors affect moisture loss, but research to quantify the effects of bole size and harvest method is limited. This study was designed to test whether bole size, harvest method, environmental factors, and the associated changes in stem moisture content of felled Douglas-fir (Pseudotsuga menziesii var. glauca Franco affected the weight-to-volume relationship of sawlogs. Thirty trees in three size classes (12.7–25.4 cm, 25.5–38.1 cm, 38.2–50.8 cm were felled and treated with one of two harvesting processing methods. Moisture content was sampled every two days for four weeks. Results showed 6% greater moisture loss in the crowns of stems that retained limbs after felling compared to stems with limbs removed after harvesting. Additionally, moisture loss rate increased as stem size decreased. The smallest size class lost 58% moisture content compared to 34% in the largest size class throughout the study duration. These stem moisture content changes showed a 17% reduction in average sawlog weight within the largest size class, shifting current W-V relationships from 2.33 tons m−3 to 1.94 tons m−3 during the third seasonal quarter for northern Idaho Douglas-fir and potentially altering relationships year-round.

Higher Leptin but Not Human Milk Macronutrient Concentration Distinguishes Normal-Weight from Obese Mothers at 1-Month Postpartum.

Science.gov (United States)

De Luca, Arnaud; Frasquet-Darrieux, Marine; Gaud, Marie-Agnès; Christin, Patricia; Boquien, Clair-Yves; Millet, Christine; Herviou, Manon; Darmaun, Dominique; Robins, Richard J; Ingrand, Pierre; Hankard, Régis

2016-01-01

Exclusively breastfed infants born to obese mothers have previously been shown to gain less weight by 1-month postpartum than infants of normal-weight mothers. Our hypothesis is that human milk composition and volume may differ between obese and normal-weight mothers. To compare human milk leptin, macronutrient concentration, and volume in obese and normal-weight mothers. Mother and infant characteristics were studied as secondary aims. This cross-sectional observational study compared 50 obese mothers matched for age, parity, ethnic origin, and educational level with 50 normal-weight mothers. Leptin, macronutrient human milk concentration, and milk volume were determined at 1 month in exclusively breastfed infants. Mother characteristics and infant growth were recorded. Human milk leptin concentration was higher in obese mothers than normal-weight mothers (4.8±2.7 vs. 2.5±1.5 ng.mL-1, pobese and normal-weight mothers in protein, lipid, carbohydrate content, and volume, nor in infant weight gain. Leptin concentration was higher in the milk of obese mothers than that of normal-weight mothers, but macronutrient concentration was not. It remains to be established whether the higher leptin content impacts on infant growth beyond the 1-month of the study period.

Expressing intrinsic volumes as rotational integrals

DEFF Research Database (Denmark)

Auneau, Jeremy Michel; Jensen, Eva Bjørn Vedel

2010-01-01

A new rotational formula of Crofton type is derived for intrinsic volumes of a compact subset of positive reach. The formula provides a functional defined on the section of X with a j-dimensional linear subspace with rotational average equal to the intrinsic volumes of X. Simplified forms of the ...

Measurement of Crystalline Lens Volume During Accommodation in a Lens Stretcher.

Science.gov (United States)

Marussich, Lauren; Manns, Fabrice; Nankivil, Derek; Maceo Heilman, Bianca; Yao, Yue; Arrieta-Quintero, Esdras; Ho, Arthur; Augusteyn, Robert; Parel, Jean-Marie

2015-07-01

To determine if the lens volume changes during accommodation. The study used data acquired on 36 cynomolgus monkey lenses that were stretched in a stepwise fashion to simulate disaccommodation. At each step, stretching force and dioptric power were measured and a cross-sectional image of the lens was acquired using an optical coherence tomography system. Images were corrected for refractive distortions and lens volume was calculated assuming rotational symmetry. The average change in lens volume was calculated and the relation between volume change and power change, and between volume change and stretching force, were quantified. Linear regressions of volume-power and volume-force plots were calculated. The mean (± SD) volume in the unstretched (accommodated) state was 97 ± 8 mm3. On average, there was a small but statistically significant (P = 0.002) increase in measured lens volume with stretching. The mean change in lens volume was +0.8 ± 1.3 mm3. The mean volume-power and volume-load slopes were -0.018 ± 0.058 mm3/D and +0.16 ± 0.40 mm3/g. Lens volume remains effectively constant during accommodation, with changes that are less than 1% on average. This result supports a hypothesis that the change in lens shape with accommodation is accompanied by a redistribution of tissue within the capsular bag without significant compression of the lens contents or fluid exchange through the capsule.

Stereological estimation of the mean and variance of nuclear volume from vertical sections

DEFF Research Database (Denmark)

Sørensen, Flemming Brandt

1991-01-01

The application of assumption-free, unbiased stereological techniques for estimation of the volume-weighted mean nuclear volume, nuclear vv, from vertical sections of benign and malignant nuclear aggregates in melanocytic skin tumours is described. Combining sampling of nuclei with uniform...... probability in a physical disector and Cavalieri's direct estimator of volume, the unbiased, number-weighted mean nuclear volume, nuclear vN, of the same benign and malignant nuclear populations is also estimated. Having obtained estimates of nuclear volume in both the volume- and number distribution...... of volume, a detailed investigation of nuclear size variability is possible. Benign and malignant nuclear populations show approximately the same relative variability with regard to nuclear volume, and the presented data are compatible with a simple size transformation from the smaller benign nuclei...

STOCK Market Differences in Correlation-Based Weighted Network

Science.gov (United States)

Youn, Janghyuk; Lee, Junghoon; Chang, Woojin

We examined the sector dynamics of Korean stock market in relation to the market volatility. The daily price data of 360 stocks for 5019 trading days (from January, 1990 to August, 2008) in Korean stock market are used. We performed the weighted network analysis and employed four measures: the average, the variance, the intensity, and the coherence of network weights (absolute values of stock return correlations) to investigate the network structure of Korean stock market. We performed regression analysis using the four measures in the seven major industry sectors and the market (seven sectors combined). We found that the average, the intensity, and the coherence of sector (subnetwork) weights increase as market becomes volatile. Except for the "Financials" sector, the variance of sector weights also grows as market volatility increases. Based on the four measures, we can categorize "Financials," "Information Technology" and "Industrials" sectors into one group, and "Materials" and "Consumer Discretionary" sectors into another group. We investigated the distributions of intrasector and intersector weights for each sector and found the differences in "Financials" sector are most distinct.

Thyroid hormones and changes in body weight and metabolic parameters in response to weight loss diets: the POUNDS LOST trial.

Science.gov (United States)

Liu, G; Liang, L; Bray, G A; Qi, L; Hu, F B; Rood, J; Sacks, F M; Sun, Q

2017-06-01

The role of thyroid hormones in diet-induced weight loss and subsequent weight regain is largely unknown. To examine the associations between thyroid hormones and changes in body weight and resting metabolic rate (RMR) in a diet-induced weight loss setting. Data analysis was conducted among 569 overweight and obese participants aged 30-70 years with normal thyroid function participating in the 2-year Prevention of Obesity Using Novel Dietary Strategies (POUNDS) LOST randomized clinical trial. Changes in body weight and RMR were assessed during the 2-year intervention. Thyroid hormones (free triiodothyronine (T3), free thyroxine (T4), total T3, total T4 and thyroid-stimulating hormone (TSH)), anthropometric measurements and biochemical parameters were assessed at baseline, 6 months and 24 months. Participants lost an average of 6.6 kg of body weight during the first 6 months and subsequently regained an average of 2.7 kg of body weight over the remaining period from 6 to 24 months. Baseline free T3 and total T3 were positively associated, whereas free T4 was inversely associated, with baseline body weight, body mass index and RMR. Total T4 and TSH were not associated with these parameters. Higher baseline free T3 and free T4 levels were significantly associated with a greater weight loss during the first 6 months (Ppressure, glucose, insulin, triglycerides and leptin at 6 months and 24 months (all P<0.05). In this diet-induced weight loss setting, higher baseline free T3 and free T4 predicted more weight loss, but not weight regain among overweight and obese adults with normal thyroid function. These findings reveal a novel role of thyroid hormones in body weight regulation and may help identify individuals more responsive to weight loss diets.

Development of realistic high-resolution whole-body voxel models of Japanese adult males and females of average height and weight, and application of models to radio-frequency electromagnetic-field dosimetry

International Nuclear Information System (INIS)

Nagaoka, Tomoaki; Watanabe, Soichi; Sakurai, Kiyoko; Kunieda, Etsuo; Watanabe, Satoshi; Taki, Masao; Yamanaka, Yukio

2004-01-01

With advances in computer performance, the use of high-resolution voxel models of the entire human body has become more frequent in numerical dosimetries of electromagnetic waves. Using magnetic resonance imaging, we have developed realistic high-resolution whole-body voxel models for Japanese adult males and females of average height and weight. The developed models consist of cubic voxels of 2 mm on each side; the models are segmented into 51 anatomic regions. The adult female model is the first of its kind in the world and both are the first Asian voxel models (representing average Japanese) that enable numerical evaluation of electromagnetic dosimetry at high frequencies of up to 3 GHz. In this paper, we will also describe the basic SAR characteristics of the developed models for the VHF/UHF bands, calculated using the finite-difference time-domain method

Design for volume reduction

NARCIS (Netherlands)

Wever, R.; Boks, C.; Stevels, A.

2007-01-01

Traditionally packaging design-for-sustainability (DfS) strongly focuses on resource conservation and material recycling. The type and amount of materials used has been the driver in design. For consumer electronics (CE) products this weight-based approach is too limited; a volume-based approach is

About an adaptively weighted Kaplan-Meier estimate.

Science.gov (United States)

Plante, Jean-François

2009-09-01

The minimum averaged mean squared error nonparametric adaptive weights use data from m possibly different populations to infer about one population of interest. The definition of these weights is based on the properties of the empirical distribution function. We use the Kaplan-Meier estimate to let the weights accommodate right-censored data and use them to define the weighted Kaplan-Meier estimate. The proposed estimate is smoother than the usual Kaplan-Meier estimate and converges uniformly in probability to the target distribution. Simulations show that the performances of the weighted Kaplan-Meier estimate on finite samples exceed that of the usual Kaplan-Meier estimate. A case study is also presented.

The Economic Impact of Weight Regain

Directory of Open Access Journals (Sweden)

Caroline E. Sheppard

2013-01-01

Full Text Available Background. Obesity is well known for being associated with significant economic repercussions. Bariatric surgery is the only evidence-based solution to this problem as well as a cost-effective method of addressing the concern. Numerous authors have calculated the cost effectiveness and cost savings of bariatric surgery; however, to date the economic impact of weight regain as a component of overall cost has not been addressed. Methods. The literature search was conducted to elucidate the direct costs of obesity and primary bariatric surgery, the rate of weight recidivism and surgical revision, and any costs therein. Results. The quoted cost of obesity in Canada was $2.0 billion–$6.7 billion in 2013 CAD. The median percentage of bariatric procedures that fail due to weight gain or insufficient weight loss is 20% (average: 21.1%±10.1%, range: 5.2–39, n=10. Revision of primary surgeries on average ranges from 2.5% to 18.4%, and depending on the procedure accounts for an additional cost between $14,000 and $50,000 USD per patient. Discussion. There was a significant deficit of the literature pertaining to the cost of revision surgery as compared with primary bariatric surgery. As such, the cycle of weight recidivism and bariatric revisions has not as of yet been introduced into any previous cost analysis of bariatric surgery.

Birth weight differences between those offered financial voucher incentives for verified smoking cessation and control participants enrolled in the Cessation in Pregnancy Incentives Trial (CPIT), employing an intuitive approach and a Complier Average Causal Effects (CACE) analysis.

Science.gov (United States)

McConnachie, Alex; Haig, Caroline; Sinclair, Lesley; Bauld, Linda; Tappin, David M

2017-07-20

The Cessation in Pregnancy Incentives Trial (CPIT), which offered financial incentives for smoking cessation during pregnancy showed a clinically and statistically significant improvement in cessation. However, infant birth weight was not seen to be affected. This study re-examines birth weight using an intuitive and a complier average causal effects (CACE) method to uncover important information missed by intention-to-treat analysis. CPIT offered financial incentives up to £400 to pregnant smokers to quit. With incentives, 68 women (23.1%) were confirmed non-smokers at primary outcome, compared to 25 (8.7%) without incentives, a difference of 14.3% (Fisher test, p financial incentives to quit. Viewed in this way, the overall birth weight gain with incentives is attributable only to potential quitters. We compared an intuitive approach to a CACE analysis. Mean birth weight of potential quitters in the incentives intervention group (who therefore quit) was 3338 g compared with potential quitters in the control group (who did not quit) 3193 g. The difference attributable to incentives, was 3338 - 3193 = 145 g (95% CI -617, +803). The mean difference in birth weight between the intervention and control groups was 21 g, and the difference in the proportion who managed to quit was 14.3%. Since the intervention consisted of the offer of incentives to quit smoking, the intervention was received by all women in the intervention group. However, "compliance" was successfully quitting with incentives, and the CACE analysis yielded an identical result, causal birth weight increase 21 g ÷ 0.143 = 145 g. Policy makers have great difficulty giving pregnant women money to stop smoking. This study indicates that a small clinically insignificant improvement in average birth weight is likely to hide an important clinically significant increase in infants born to pregnant smokers who want to stop but cannot achieve smoking cessation without the addition of financial

EDITAR: a module for reaction rate editing and cross-section averaging within the AUS neutronics code system

International Nuclear Information System (INIS)

Robinson, G.S.

1986-03-01

The EDITAR module of the AUS neutronics code system edits one and two-dimensional flux data pools produced by other AUS modules to form reaction rates for materials and their constituent nuclides, and to average cross sections over space and energy. The module includes a Bsub(L) flux calculation for application to cell leakage. The STATUS data pool of the AUS system is used to enable the 'unsmearing' of fluxes and nuclide editing with minimal user input. The module distinguishes between neutron and photon groups, and printed reaction rates are formed accordingly. Bilinear weighting may be used to obtain material reactivity worths and to average cross sections. Bilinear weighting is at present restricted to diffusion theory leakage estimates made using mesh-average fluxes

[The effect of sibutramine on weight loss in obese adolescents].

Science.gov (United States)

Franco, Ruth Rocha; Cominato, Louise; Damiani, Durval

2014-04-01

To evaluate the effect of sibutramine on weight loss in obese adolescents. A double-blind controlled study lasting 13 months. The study included 73 obese adolescents of both sexes aged between 10 and 18 years. Laboratory tests and imaging studies were performed before, during wash-out, and at the end of 13 months. The percentage of patients who lost 10% of their initial weight in the placebo group was 46%, and in the sibutramine group was 75%. When placebo was used, average weight rose by 1.61 kg, and BMI decreased by 0.24 kg/m(2) whereas with the use of sibutramine, weight decreased by 4.47 kg, and average BMI decreased, 2.38 kg/m(2), with p Sibutramine induced significantly more weight loss in obese adolescents compared with placebo, without significant side effects. The weight loss curve was different depending on the moment sibutramine was introduced. This finding indicates that the best time to start sibutramine is when adhesion begins to fail.

Newborn birth weight in normal pregnancy in rural Telangana

Directory of Open Access Journals (Sweden)

Basanta M Hota

2017-01-01

Conclusion: Abnormal birth weight leads to many complications, both immediate and remote. However, to predict and manage such complications, one must know the average newborn birth weight. This study is the first of its kind in rural Telangana.

Factors contributing to initial weight loss among adolescents with polycystic ovary syndrome.

Science.gov (United States)

Geier, L M; Bekx, M T; Connor, E L

2012-12-01

To evaluate the impact of a multidisciplinary clinic on weight management among adolescents with PCOS. 140 adolescent females were evaluated in a multidisciplinary PCOS clinic from March 2005 to December 2008. The team included a pediatric endocrinologist, health psychologist, dietitian, and pediatric gynecologist. 110 were diagnosed with PCOS based on the Rotterdam Criteria. Height, weight, BMI, number of subspecialists seen, use of metformin, and compliance with return visits were obtained from medical records. American Family Children's Hospital in Madison, Wisconsin. 110 adolescent females with polycystic ovary syndrome. Consultation with a dietitian and health psychologist. Change in weight. The average age at first visit was 15.9 years. The average BMI was 34.7 kg/m(2) (range 18.1-55.5). Seventy-six percent had an initial BMI above the 95(th) percentile. Interactions with providers at the initial visit included a pediatric endocrinologist (100%), health psychologist (60.9%), dietitian (75.5%) and gynecologist (70.9%). Seventy one percent returned for a follow-up visit, (average time of 4.5 months between visits) with 57% achieving weight loss (average 3.5 kg) and an additional 12.6% demonstrating no significant weight gain (weight loss/stabilization. In this multidisciplinary clinic for adolescents with PCOS, nearly 70% of patients succeeded in short-term weight stabilization, with 57% demonstrating weight loss. Interactions with the health psychologist and dietitian appeared to play a key role in successful weight control, supporting the importance of psychology and nutrition expertise in the management of this disorder. Copyright © 2012 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Blade size and weight effects in shovel design.

Science.gov (United States)

Freivalds, A; Kim, Y J

1990-03-01

The shovel is a basic tool that has undergone only nominal systematic design changes. Although previous studies found shovel-weight and blade-size effects of shovelling, the exact trade-off between the two has not been quantified. Energy expenditure, heart rate, ratings of perceived exertion and shovelling performance were measured on five subjects using five shovels with varying blade sizes and weights to move sand. Energy expenditure, normalised to subject weight and load handled, varied quadratically with the blade-size/shovel-weight (B/W) ratio. Minimum energy cost was at B/W = 0.0676 m2/kg, which for an average subject and average load would require an acceptable 5.16 kcal/min of energy expenditure. Subjects, through the ratings of perceived exertion, also strongly preferred the lighter shovels without regard to blade size. Too large a blade or too heavy a shovel increased energy expenditure beyond acceptable levels, while too small a blade reduced efficiency of the shovelling.

A novel power spectrum calculation method using phase-compensation and weighted averaging for the estimation of ultrasound attenuation.

Science.gov (United States)

Heo, Seo Weon; Kim, Hyungsuk

2010-05-01

An estimation of ultrasound attenuation in soft tissues is critical in the quantitative ultrasound analysis since it is not only related to the estimations of other ultrasound parameters, such as speed of sound, integrated scatterers, or scatterer size, but also provides pathological information of the scanned tissue. However, estimation performances of ultrasound attenuation are intimately tied to the accurate extraction of spectral information from the backscattered radiofrequency (RF) signals. In this paper, we propose two novel techniques for calculating a block power spectrum from the backscattered ultrasound signals. These are based on the phase-compensation of each RF segment using the normalized cross-correlation to minimize estimation errors due to phase variations, and the weighted averaging technique to maximize the signal-to-noise ratio (SNR). The simulation results with uniform numerical phantoms demonstrate that the proposed method estimates local attenuation coefficients within 1.57% of the actual values while the conventional methods estimate those within 2.96%. The proposed method is especially effective when we deal with the signal reflected from the deeper depth where the SNR level is lower or when the gated window contains a small number of signal samples. Experimental results, performed at 5MHz, were obtained with a one-dimensional 128 elements array, using the tissue-mimicking phantoms also show that the proposed method provides better estimation results (within 3.04% of the actual value) with smaller estimation variances compared to the conventional methods (within 5.93%) for all cases considered. Copyright 2009 Elsevier B.V. All rights reserved.

molecular weight control of a batch suspension polymerization reactor

International Nuclear Information System (INIS)

Shahrokhi, M.; Fanaei, M. A.

2002-01-01

This paper concerns molecular weight control of a batch polymerization reactor where suspension polymerization of methyl methylacrylate (MMA) takes place. For this purpose, a cascade control structure with two control loops has been selected. The slave loop is used for temperature control using on-line temperature measurements, and the master loop controls the average molecular weights based on its estimated values. Two different control algorithms namely proportional-integral (PI) controller and globally linearizing controller (GLC) have been used for temperature control. An estimator, which has the structure of an extended Kalman filter(EKF), is used for estimating monomer conversion and average molecular weights of polymer using reactor temperature measurements. The performance of proposed control algorithm is evaluated through simulation and experimental studies. The results indicate that a constant average molecular weight cannot be achieved in case of strong gel effect. However, the polydispersity of product will be lower in comparison to isothermal operation. It is also shown that in case of mo dek mismatch, the performance of cascade control is superior compared to the case where only reactor temperature is controlled based on desired temperature trajectory obtained through cascade strategy

Analysis of average radiation widths of neutron resonances

International Nuclear Information System (INIS)

Malezki, H.; Popov, A.B.; Trzeciak, K.

1982-01-01

On the basis of the available data on parameters of neutron resonances average values of radiation widths (GITAsub(γ)) are calculated for a wide range of nuclei in the 50 upto 250 atomic weight range. Experimental values are compared with different variants of theoretical estimates of GITAsub(γ) which are reduced to the GITAsub(γ) dependence upon atomic weight A, excitation energy U and level density parameter a as GITAsub(γ)=CAsup(α)Usup(β)asup(γ). Besides, empirical values C, α, β, γ are selected satisfying the experimental data best of all. It is determined that the use of a=kA hypothesis leads to a sufficiently better agreement between all theoretical estimates of GITAsub(γ) and experimental values. It turned out that the estimations by Weisskopf, Bondarenko-Urin or with empirically chosen parameters give an approximately similar correspondence of calculated values GITAsub(γ)sup(p) to experimental data [ru

Is Weight-Based Adjustment of Automatic Exposure Control Necessary for the Reduction of Chest CT Radiation Dose?

Science.gov (United States)

Prakash, Priyanka; Gilman, Matthew D.; Shepard, Jo-Anne O.; Digumarthy, Subba R.

2010-01-01

Objective To assess the effects of radiation dose reduction in the chest CT using a weight-based adjustment of the automatic exposure control (AEC) technique. Materials and Methods With Institutional Review Board Approval, 60 patients (mean age, 59.1 years; M:F = 35:25) and 57 weight-matched patients (mean age, 52.3 years, M:F = 25:32) were scanned using a weight-adjusted AEC and non-weight-adjusted AEC, respectively on a 64-slice multidetector CT with a 0.984:1 pitch, 0.5 second rotation time, 40 mm table feed/rotation, and 2.5 mm section thickness. Patients were categorized into 3 weight categories; 90 kg (n = 48). Patient weights, scanning parameters, CT dose index volumes (CTDIvol) and dose length product (DLP) were recorded, while effective dose (ED) was estimated. Image noise was measured in the descending thoracic aorta. Data were analyzed using a standard statistical package (SAS/STAT) (Version 9.1, SAS institute Inc, Cary, NC). Results Compared to the non-weight-adjusted AEC, the weight-adjusted AEC technique resulted in an average decrease of 29% in CTDIvol and a 27% effective dose reduction (p 91 kg weight groups, respectively, compared to 20.3, 27.9 and 32.8 mGy, with non-weight-adjusted AEC. No significant difference was observed for objective image noise between the chest CT acquired with the non-weight-adjusted (15.0 ± 3.1) and weight-adjusted (16.1 ± 5.6) AEC techniques (p > 0.05). Conclusion The results of this study suggest that AEC should be tailored according to patient weight. Without weight-based adjustment of AEC, patients are exposed to a 17 - 43% higher radiation-dose from a chest CT. PMID:20046494

Is Weight-Based Adjustment of Automatic Exposure Control Necessary for the Reduction of Chest CT Radiation Dose?

Energy Technology Data Exchange (ETDEWEB)

Prakash, Priyanka; Kalra, Mannudeep K.; Gilman, Matthew D.; Shepard, Jo Anne O.; Digumarthy, Subba R. [Massachusetts General Hospital and Harvard Medical School, Boston (United States)

2010-02-15

To assess the effects of radiation dose reduction in the chest CT using a weight-based adjustment of the automatic exposure control (AEC) technique. With Institutional Review Board Approval, 60 patients (mean age, 59.1 years; M:F = 35:25) and 57 weight-matched patients (mean age, 52.3 years, M:F = 25:32) were scanned using a weight-adjusted AEC and nonweight- adjusted AEC, respectively on a 64-slice multidetector CT with a 0.984:1 pitch, 0.5 second rotation time, 40 mm table feed/rotation, and 2.5 mm section thickness. Patients were categorized into 3 weight categories; < 60 kg (n = 17), 60-90 kg (n = 52), and > 90 kg (n = 48). Patient weights, scanning parameters, CT dose index volumes (CTDIvol) and dose length product (DLP) were recorded, while effective dose (ED) was estimated. Image noise was measured in the descending thoracic aorta. Data were analyzed using a standard statistical package (SAS/STAT) (Version 9.1, SAS institute Inc, Cary, NC). Compared to the non-weight-adjusted AEC, the weight-adjusted AEC technique resulted in an average decrease of 29% in CTDIvol and a 27% effective dose reduction (p < 0.0001). With weight-adjusted AEC, the CTDIvol decreased to 15.8, 15.9, and 27.3 mGy for the < 60, 60-90 and > 91 kg weight groups, respectively, compared to 20.3, 27.9 and 32.8 mGy, with non-weight adjusted AEC. No significant difference was observed for objective image noise between the chest CT acquired with the non-weight-adjusted (15.0 {+-} 3.1) and weight-adjusted (16.1 {+-} 5.6) AEC techniques (p > 0.05). The results of this study suggest that AEC should be tailored according to patient weight. Without weight-based adjustment of AEC, patients are exposed to a 17 - 43% higher radiation-dose from a chest CT.

Association between smoking cessation and weight gain in treatment-seeking African Americans.

Science.gov (United States)

Tan, Marcia M; Okuyemi, Kolawole S; Resnicow, Ken; Dietz, Noella A; Antoni, Michael H; Webb Hooper, Monica

2018-06-01

Research has shown that African Americans gain more than average weight after smoking cessation. However, African Americans have been underrepresented in post-cessation weight gain research. The current study examined 1) the pattern of weight gain and 2) the association between smoking status and weight gain in a sample of African Americans seeking smoking cessation treatment. Data were drawn from a randomized controlled trial testing the efficacy of a 4-week culturally specific smoking cessation cognitive behavioral therapy (CBT) intervention among African American smokers (N = 342). Weight was measured and self-reported smoking status was biochemically verified at baseline, end of counseling, 3-, 6-, and 12-month follow-ups. Random effects multilevel modeling was used to examine weight gain over twelve months post CBT, and a fully unconditional model tested the pattern of weight gain over time. Smoking status was included as a time-varying factor to examine its effect on weight gain, controlling for potential confounding variables. Weight significantly increased among those who remained abstinent over 12 months post CBT [average gain of seven lbs. (three kg)]. Controlling for covariates, abstinence was predictive of the rate of weight gain for those with high weight concern. Weight gain among African American abstainers was comparable to the average post-cessation weight gain observed among the general population. It is possible that exposure to CBT (culturally specific or standard) may have mitigated excessive weight gain. Future research should assess predictors of weight gain in African American smokers to inform future smoking cessation interventions and help elucidate factors that contribute to tobacco- and obesity-related health disparities. Copyright © 2018 Elsevier Ltd. All rights reserved.

Change in brain and lesion volumes after CEE therapies

Science.gov (United States)

Espeland, Mark A.; Hogan, Patricia E.; Resnick, Susan M.; Bryan, R. Nick; Robinson, Jennifer G.; Goveas, Joseph S.; Davatzikos, Christos; Kuller, Lewis H.; Williamson, Jeff D.; Bushnell, Cheryl D.; Shumaker, Sally A.

2014-01-01

Objectives: To determine whether smaller brain volumes in older women who had completed Women's Health Initiative (WHI)-assigned conjugated equine estrogen–based hormone therapy (HT), reported by WHI Memory Study (WHIMS)-MRI, correspond to a continuing increased rate of atrophy an average of 6.1 to 7.7 years later in WHIMS-MRI2. Methods: A total of 1,230 WHI participants were contacted: 797 (64.8%) consented, and 729 (59%) were rescanned an average of 4.7 years after the initial MRI scan. Mean annual rates of change in total brain volume, the primary outcome, and rates of change in ischemic lesion volumes, the secondary outcome, were compared between treatment groups using mixed-effect models with adjustment for trial, clinical site, age, intracranial volumes, and time between MRI measures. Results: Total brain volume decreased an average of 3.22 cm3/y in the active arm and 3.07 cm3/y in the placebo arm (p = 0.53). Total ischemic lesion volumes increased in both arms at a rate of 0.12 cm3/y (p = 0.88). Conclusions: Conjugated equine estrogen–based postmenopausal HT, previously assigned at WHI baseline, did not affect rates of decline in brain volumes or increases in brain lesion volumes during the 4.7 years between the initial and follow-up WHIMS-MRI studies. Smaller frontal lobe volumes were observed as persistent group differences among women assigned to active HT compared with placebo. Women with a history of cardiovascular disease treated with active HT, compared with placebo, had higher rates of accumulation in white matter lesion volume and total brain lesion volume. Further study may elucidate mechanisms that explain these findings. PMID:24384646

Total volume versus bouts

DEFF Research Database (Denmark)

Chinapaw, Mai; Klakk, Heidi; Møller, Niels Christian

2018-01-01

BACKGROUND/OBJECTIVES: Examine the prospective relationship of total volume versus bouts of sedentary behaviour (SB) and moderate-to-vigorous physical activity (MVPA) with cardiometabolic risk in children. In addition, the moderating effects of weight status and MVPA were explored. SUBJECTS....../METHODS: Longitudinal study including 454 primary school children (mean age 10.3 years). Total volume and bouts (i.e. ≥10 min consecutive minutes) of MVPA and SB were assessed by accelerometry in Nov 2009/Jan 2010 (T1) and Aug/Oct 2010 (T2). Triglycerides, total cholesterol/HDL cholesterol ratio (TC:HDLC ratio......, with or without mutual adjustments between MVPA and SB. The moderating effects of weight status and MVPA (for SB only) were examined by adding interaction terms. RESULTS: Children engaged daily in about 60 min of total MVPA and 0-15 min/week in MVPA bouts. Mean total sedentary time was around 7 h/day with over 3...

Optimal bounds and extremal trajectories for time averages in nonlinear dynamical systems

Science.gov (United States)

Tobasco, Ian; Goluskin, David; Doering, Charles R.

2018-02-01

For any quantity of interest in a system governed by ordinary differential equations, it is natural to seek the largest (or smallest) long-time average among solution trajectories, as well as the extremal trajectories themselves. Upper bounds on time averages can be proved a priori using auxiliary functions, the optimal choice of which is a convex optimization problem. We prove that the problems of finding maximal trajectories and minimal auxiliary functions are strongly dual. Thus, auxiliary functions provide arbitrarily sharp upper bounds on time averages. Moreover, any nearly minimal auxiliary function provides phase space volumes in which all nearly maximal trajectories are guaranteed to lie. For polynomial equations, auxiliary functions can be constructed by semidefinite programming, which we illustrate using the Lorenz system.

Diet in the management of weight loss

OpenAIRE

Strychar, Irene

2006-01-01

Obesity is an established risk factor for numerous chronic diseases, and successful treatment will have an important impact on medical resources utilization, health care costs, and patient quality of life. With over 60% of our population being overweight, physicians face a major challenge in assisting patients in the process of weight loss and weight-loss maintenance. Low-calorie diets can lower total body weight by an average of 8% in the short term. These diets are well-tolerated and charac...

Epidemic spreading on weighted complex networks

International Nuclear Information System (INIS)

Sun, Ye; Liu, Chuang; Zhang, Chu-Xu; Zhang, Zi-Ke

2014-01-01

Nowadays, the emergence of online services provides various multi-relation information to support the comprehensive understanding of the epidemic spreading process. In this Letter, we consider the edge weights to represent such multi-role relations. In addition, we perform detailed analysis of two representative metrics, outbreak threshold and epidemic prevalence, on SIS and SIR models. Both theoretical and simulation results find good agreements with each other. Furthermore, experiments show that, on fully mixed networks, the weight distribution on edges would not affect the epidemic results once the average weight of whole network is fixed. This work may shed some light on the in-depth understanding of epidemic spreading on multi-relation and weighted networks.

Epidemic spreading on weighted complex networks

Energy Technology Data Exchange (ETDEWEB)

Sun, Ye [Institute of Information Economy, Hangzhou Normal University, Hangzhou 311121 (China); Alibaba Research Center of Complexity Science, Hangzhou Normal University, Hangzhou 311121 (China); Liu, Chuang, E-mail: liuchuang@hznu.edu.cn [Institute of Information Economy, Hangzhou Normal University, Hangzhou 311121 (China); Alibaba Research Center of Complexity Science, Hangzhou Normal University, Hangzhou 311121 (China); Zhang, Chu-Xu [Institute of Information Economy, Hangzhou Normal University, Hangzhou 311121 (China); Alibaba Research Center of Complexity Science, Hangzhou Normal University, Hangzhou 311121 (China); Zhang, Zi-Ke, E-mail: zhangzike@gmail.com [Institute of Information Economy, Hangzhou Normal University, Hangzhou 311121 (China); Alibaba Research Center of Complexity Science, Hangzhou Normal University, Hangzhou 311121 (China)

2014-01-31

Nowadays, the emergence of online services provides various multi-relation information to support the comprehensive understanding of the epidemic spreading process. In this Letter, we consider the edge weights to represent such multi-role relations. In addition, we perform detailed analysis of two representative metrics, outbreak threshold and epidemic prevalence, on SIS and SIR models. Both theoretical and simulation results find good agreements with each other. Furthermore, experiments show that, on fully mixed networks, the weight distribution on edges would not affect the epidemic results once the average weight of whole network is fixed. This work may shed some light on the in-depth understanding of epidemic spreading on multi-relation and weighted networks.

Real-time interpolation for true 3-dimensional ultrasound image volumes.

Science.gov (United States)

Ji, Songbai; Roberts, David W; Hartov, Alex; Paulsen, Keith D

2011-02-01

We compared trilinear interpolation to voxel nearest neighbor and distance-weighted algorithms for fast and accurate processing of true 3-dimensional ultrasound (3DUS) image volumes. In this study, the computational efficiency and interpolation accuracy of the 3 methods were compared on the basis of a simulated 3DUS image volume, 34 clinical 3DUS image volumes from 5 patients, and 2 experimental phantom image volumes. We show that trilinear interpolation improves interpolation accuracy over both the voxel nearest neighbor and distance-weighted algorithms yet achieves real-time computational performance that is comparable to the voxel nearest neighbor algrorithm (1-2 orders of magnitude faster than the distance-weighted algorithm) as well as the fastest pixel-based algorithms for processing tracked 2-dimensional ultrasound images (0.035 seconds per 2-dimesional cross-sectional image [76,800 pixels interpolated, or 0.46 ms/1000 pixels] and 1.05 seconds per full volume with a 1-mm(3) voxel size [4.6 million voxels interpolated, or 0.23 ms/1000 voxels]). On the basis of these results, trilinear interpolation is recommended as a fast and accurate interpolation method for rectilinear sampling of 3DUS image acquisitions, which is required to facilitate subsequent processing and display during operating room procedures such as image-guided neurosurgery.

Grey matter volume in adolescents with anorexia nervosa and associated eating disorder symptoms.

Science.gov (United States)

Martin Monzon, Beatriz; Henderson, Luke A; Madden, Sloane; Macefield, Vaughan G; Touyz, Stephen; Kohn, Michael R; Clarke, Simon; Foroughi, Nasim; Hay, Phillipa

2017-10-01

Anorexia nervosa (AN) is a mental health disorder of complex aetiology. Previous neuroimaging studies have found consistent global reductions in global grey matter volume of underweight girls with AN; however, differences in regional grey matter volumes are less consistent. The aims of this study were to investigate grey matter regional volumes of adolescent girls with AN before and after weight recovery and the relationship of any changes with clinical characteristics. We collected high-resolution T1-weighted images from 26 underweight girls with AN before weight gain and 20 healthy control volunteers. Clinical features were assessed using the Eating Disorder Examination Questionnaire. AN subjects displayed reduced grey matter volumes in the insula, amygdala, prefrontal, hippocampal and cingulate cortices and the precuneus, relative to healthy controls. In a subset of 10 AN subjects who were followed after weight recovery, grey matter volumes increased to near-control levels in the orbito- and medial prefrontal, insular, left hippocampal and mid- and posterior cingulate cortices and precuneus. The recovery of the right anterior thalamus and the left orbitofrontal cortex was correlated with improvements in eating concerns and shape concerns, respectively. However, large parts of the anterior cingulate cortex, caudate nuclei and right hippocampus did not display any grey matter recovery following a short-term of treatment. These results show that in adolescents with AN, some brain regions display marked recovery in grey matter volume following weight recovery, whereas others do not, considering grey mater recovery possibly linked to symptom improvement. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Semi-automatic delineation using weighted CT-MRI registered images for radiotherapy of nasopharyngeal cancer

Energy Technology Data Exchange (ETDEWEB)

Fitton, I. [European Georges Pompidou Hospital, Department of Radiology, 20 rue Leblanc, 75015, Paris (France); Cornelissen, S. A. P. [Image Sciences Institute, UMC, Department of Radiology, P.O. Box 85500, 3508 GA Utrecht (Netherlands); Duppen, J. C.; Rasch, C. R. N.; Herk, M. van [The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Department of Radiotherapy, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Steenbakkers, R. J. H. M. [University Medical Center Groningen, Department of Radiation Oncology, Hanzeplein 1, 9713 GZ Groningen (Netherlands); Peeters, S. T. H. [UZ Gasthuisberg, Herestraat 49, 3000 Leuven, Belgique (Belgium); Hoebers, F. J. P. [Maastricht University Medical Center, Department of Radiation Oncology (MAASTRO clinic), GROW School for Oncology and Development Biology Maastricht, 6229 ET Maastricht (Netherlands); Kaanders, J. H. A. M. [UMC St-Radboud, Department of Radiotherapy, Geert Grooteplein 32, 6525 GA Nijmegen (Netherlands); Nowak, P. J. C. M. [ERASMUS University Medical Center, Department of Radiation Oncology,Groene Hilledijk 301, 3075 EA Rotterdam (Netherlands)

2011-08-15

Purpose: To develop a delineation tool that refines physician-drawn contours of the gross tumor volume (GTV) in nasopharynx cancer, using combined pixel value information from x-ray computed tomography (CT) and magnetic resonance imaging (MRI) during delineation. Methods: Operator-guided delineation assisted by a so-called ''snake'' algorithm was applied on weighted CT-MRI registered images. The physician delineates a rough tumor contour that is continuously adjusted by the snake algorithm using the underlying image characteristics. The algorithm was evaluated on five nasopharyngeal cancer patients. Different linear weightings CT and MRI were tested as input for the snake algorithm and compared according to contrast and tumor to noise ratio (TNR). The semi-automatic delineation was compared with manual contouring by seven experienced radiation oncologists. Results: A good compromise for TNR and contrast was obtained by weighing CT twice as strong as MRI. The new algorithm did not notably reduce interobserver variability, it did however, reduce the average delineation time by 6 min per case. Conclusions: The authors developed a user-driven tool for delineation and correction based a snake algorithm and registered weighted CT image and MRI. The algorithm adds morphological information from CT during the delineation on MRI and accelerates the delineation task.

Notes on Well-Posed, Ensemble Averaged Conservation Equations for Multiphase, Multi-Component, and Multi-Material Flows

International Nuclear Information System (INIS)

Ray A. Berry

2005-01-01

At the INL researchers and engineers routinely encounter multiphase, multi-component, and/or multi-material flows. Some examples include: Reactor coolant flows Molten corium flows Dynamic compaction of metal powders Spray forming and thermal plasma spraying Plasma quench reactor Subsurface flows, particularly in the vadose zone Internal flows within fuel cells Black liquor atomization and combustion Wheat-chaff classification in combine harvesters Generation IV pebble bed, high temperature gas reactor The complexity of these flows dictates that they be examined in an averaged sense. Typically one would begin with known (or at least postulated) microscopic flow relations that hold on the ''small'' scale. These include continuum level conservation of mass, balance of species mass and momentum, conservation of energy, and a statement of the second law of thermodynamics often in the form of an entropy inequality (such as the Clausius-Duhem inequality). The averaged or macroscopic conservation equations and entropy inequalities are then obtained from the microscopic equations through suitable averaging procedures. At this stage a stronger form of the second law may also be postulated for the mixture of phases or materials. To render the evolutionary material flow balance system unique, constitutive equations and phase or material interaction relations are introduced from experimental observation, or by postulation, through strict enforcement of the constraints or restrictions resulting from the averaged entropy inequalities. These averaged equations form the governing equation system for the dynamic evolution of these mixture flows. Most commonly, the averaging technique utilized is either volume or time averaging or a combination of the two. The flow restrictions required for volume and time averaging to be valid can be severe, and violations of these restrictions are often found. A more general, less restrictive (and far less commonly used) type of averaging known as

Multimodal Discrimination of Schizophrenia Using Hybrid Weighted Feature Concatenation of Brain Functional Connectivity and Anatomical Features with an Extreme Learning Machine

Directory of Open Access Journals (Sweden)

Muhammad Naveed Iqbal Qureshi

2017-09-01

Full Text Available Multimodal features of structural and functional magnetic resonance imaging (MRI of the human brain can assist in the diagnosis of schizophrenia. We performed a classification study on age, sex, and handedness-matched subjects. The dataset we used is publicly available from the Center for Biomedical Research Excellence (COBRE and it consists of two groups: patients with schizophrenia and healthy controls. We performed an independent component analysis and calculated global averaged functional connectivity-based features from the resting-state functional MRI data for all the cortical and subcortical anatomical parcellation. Cortical thickness along with standard deviation, surface area, volume, curvature, white matter volume, and intensity measures from the cortical parcellation, as well as volume and intensity from sub-cortical parcellation and overall volume of cortex features were extracted from the structural MRI data. A novel hybrid weighted feature concatenation method was used to acquire maximal 99.29% (P < 0.0001 accuracy which preserves high discriminatory power through the weight of the individual feature type. The classification was performed by an extreme learning machine, and its efficiency was compared to linear and non-linear (radial basis function support vector machines, linear discriminant analysis, and random forest bagged tree ensemble algorithms. This article reports the predictive accuracy of both unimodal and multimodal features after 10-by-10-fold nested cross-validation. A permutation test followed the classification experiment to assess the statistical significance of the classification results. It was concluded that, from a clinical perspective, this feature concatenation approach may assist the clinicians in schizophrenia diagnosis.

Using Mobile Device Samples to Estimate Traffic Volumes

Science.gov (United States)

2017-12-01

In this project, TTI worked with StreetLight Data to evaluate a beta version of its traffic volume estimates derived from global positioning system (GPS)-based mobile devices. TTI evaluated the accuracy of average annual daily traffic (AADT) volume :...

Preoperative evaluation of liver volume parameters in living related donors by spiral computed tomography

International Nuclear Information System (INIS)

Michalak, M.; Pacho, R.; Pruszynski, B.; Paluszkiewicz, R.; Hevelke, P.; Krawczyk, M.

2002-01-01

The objective of the study is to assess the use of spiral computed tomography in the evaluation of the volume of the liver, its lobes, and selected segments in the preoperative period and to validate the used measurements. Thirty five potential donors (15 women and 20 men) aged 21-65 years were included. Based on the CT liver findings in the venous-portal phase and segment division of the liver according Couinaud the liver volume was calculated manually be a planimetric method, after making outlines of all liver sections. The volumes of lobes and selected segments were assessed by the same technique. The volumes of the resected liver segments calculated based on the CT findings were compared with appropriate measurements made during the operation. The total liver volume ranged between 804 and 1842 cm 3 (mean - 1456 cm 3 , standard deviation [SD] - 247). The volume of the right liver lobe including caudate lobe was 555 cm 3 to 1382 cm 3 (mean - 1024, SD - 186) that is in average 70.4% of the total liver volume. The volume of the left liver lobe ranged between 156 and 778 cm 3 (mean - 431, SD - 123) that is in average 29.6% of the total liver volume. The volume of segments 2+3 was 72 to 426 cm 3 (mean - 237 cm 3 , SD - 79) that is in average 16.2% of the total liver volume. The volume of the segment 4 ranged between 84 and 366 cm 3 (mean - 196, SD - 70) that is in average 13.4% of the total liver volume. CT makes possible to assess the volume of the liver, of its lobes and selected segments and it is an important modality for the classification of method of operation (segmentectomy, left hepatectomy, right hepatectomy). This method is accurate and reproducible. The liver part volumes calculated preoperatively in the majority of cases revealed to be smaller than in reality in average of 12.1%. (author)

Averaging hydraulic head, pressure head, and gravitational head in subsurface hydrology, and implications for averaged fluxes, and hydraulic conductivity

Directory of Open Access Journals (Sweden)

G. H. de Rooij

2009-07-01

Full Text Available Current theories for water flow in porous media are valid for scales much smaller than those at which problem of public interest manifest themselves. This provides a drive for upscaled flow equations with their associated upscaled parameters. Upscaling is often achieved through volume averaging, but the solution to the resulting closure problem imposes severe restrictions to the flow conditions that limit the practical applicability. Here, the derivation of a closed expression of the effective hydraulic conductivity is forfeited to circumvent the closure problem. Thus, more limited but practical results can be derived. At the Representative Elementary Volume scale and larger scales, the gravitational potential and fluid pressure are treated as additive potentials. The necessary requirement that the superposition be maintained across scales is combined with conservation of energy during volume integration to establish consistent upscaling equations for the various heads. The power of these upscaling equations is demonstrated by the derivation of upscaled water content-matric head relationships and the resolution of an apparent paradox reported in the literature that is shown to have arisen from a violation of the superposition principle. Applying the upscaling procedure to Darcy's Law leads to the general definition of an upscaled hydraulic conductivity. By examining this definition in detail for porous media with different degrees of heterogeneity, a series of criteria is derived that must be satisfied for Darcy's Law to remain valid at a larger scale.

PET imaging of thin objects: measuring the effects of positron range and partial-volume averaging in the leaf of Nicotiana tabacum

Energy Technology Data Exchange (ETDEWEB)

Alexoff, David L., E-mail: alexoff@bnl.gov; Dewey, Stephen L.; Vaska, Paul; Krishnamoorthy, Srilalan; Ferrieri, Richard; Schueller, Michael; Schlyer, David J.; Fowler, Joanna S.

2011-02-15

Introduction: PET imaging in plants is receiving increased interest as a new strategy to measure plant responses to environmental stimuli and as a tool for phenotyping genetically engineered plants. PET imaging in plants, however, poses new challenges. In particular, the leaves of most plants are so thin that a large fraction of positrons emitted from PET isotopes ({sup 18}F, {sup 11}C, {sup 13}N) escape while even state-of-the-art PET cameras have significant partial-volume errors for such thin objects. Although these limitations are acknowledged by researchers, little data have been published on them. Methods: Here we measured the magnitude and distribution of escaping positrons from the leaf of Nicotiana tabacum for the radionuclides {sup 18}F, {sup 11}C and {sup 13}N using a commercial small-animal PET scanner. Imaging results were compared to radionuclide concentrations measured from dissection and counting and to a Monte Carlo simulation using GATE (Geant4 Application for Tomographic Emission). Results: Simulated and experimentally determined escape fractions were consistent. The fractions of positrons (mean{+-}S.D.) escaping the leaf parenchyma were measured to be 59{+-}1.1%, 64{+-}4.4% and 67{+-}1.9% for {sup 18}F, {sup 11}C and {sup 13}N, respectively. Escape fractions were lower in thicker leaf areas like the midrib. Partial-volume averaging underestimated activity concentrations in the leaf blade by a factor of 10 to 15. Conclusions: The foregoing effects combine to yield PET images whose contrast does not reflect the actual activity concentrations. These errors can be largely corrected by integrating activity along the PET axis perpendicular to the leaf surface, including detection of escaped positrons, and calculating concentration using a measured leaf thickness.

Anthropometrics parameters and neonatal outcomes from newborns of deliveries women with low weight

Directory of Open Access Journals (Sweden)

Joe Luiz Vieira Garcia Novo

2012-04-01

Full Text Available ABSTRACT Objectives: to assess the anthropometrics assets and outcomes of birthplace newborns from patients classified how low weight through the body weight index. Methods: a retrospective study of patients in labor and newborns from Hospital Santa Lucinda since 03/2009 to 02/2010: 19 of the study group (low weight and 50 of the control group (normal weight. The maternal variables included were: age, parity, puerperium; in the newborns were observed: sex, vitality, anthropometrics values, and outcomes. The statistical analysis involved the use Bioestat 5.0 program. Results: the middle perimeter head of newborns from low weight patients were 33,3 cm, and in the control group were 33,7 cm (p = 0,098; middle left arm perimeter were 10,0 cm and 10,3 cm (p = 0, 097; average weight: 2986,84 and 3165,32 g (p = 0, 0423, average length: 48,37 and 48, 77 cm (p = 0,2165 respectively. The average vitality from newborns after 1 and 5 minutes were: 8,1 - 8,1 (p = 0,9144 and 8,9 - 9,0 (p = 0,911. Conclusion: the weights of newborns from low weight patients in labor denote lower than normal weight patients. Low weight patients signify a risk group during the prenatal care, because there is more probability to be born low weight newborns. Prophylactics educating programs must be realized in order to avoid probable risks in low weight pregnant patients. Support PIBIC - CEPE

Weights and hematology of wild black bears during hibernation

Science.gov (United States)

DelGiudice, Glenn D.; Rogers, Lynn L.; Allen, Arthur W.; Seal, U.S.

1991-01-01

We compared weights and hematological profiles of adult (greater than 3-yr-old) female black bears (Ursus americanus) during hibernation (after 8 January). We handled 28 bears one to four times (total of 47) over 4 yr of varying mast and berry production. Mean weight of lactating bears was greater (P less than 0.0001) than that of non-lactating females. White blood cells (P less than 0.05) and mean corpuscular volume (P = 0.005) also differed between lactating and non-lactating bears. Hemoglobin (P = 0.006) and mean corpuscular hemoglobin concentration (P = 0.02) varied among years; values were lowest during 1975, following decreased precipitation and the occurrence of a second year of mast and berry crop shortages in a three-year period. Significant (P less than 0.05) interaction between reproductive status (lactating versus non-lactating) and study year for hemoglobin, red blood cells, and packed cell volume, and increased mean corpuscular volume, suggested a greater nutritional challenge for lactating females compared to non-lactating females during the 1975 denning season. Our data suggest that hematological characteristics of denning bears may be more sensitive than weights as indicators of annual changes in nutritional status; however, other influential factors, in addition to mast and berry crop production, remain to be examined.

77 FR 8101 - Antidumping Proceedings: Calculation of the Weighted-Average Dumping Margin and Assessment Rate...

Science.gov (United States)

2012-02-14

...), US--Zeroing (Japan), US--Stainless Steel (Mexico), and US--Continued Zeroing (EC) found the denial of... comparisons between transaction-specific export prices and average normal values and does not offset the amount of dumping that is found with the results of comparisons for which the transaction-specific export...

Changes in infant disposable diaper weights at selected intervals post-wetting.

Science.gov (United States)

Carlisle, Joan; Moore, Amanda; Cooper, Alyssa; Henderson, Terri; Mayfield, Debbie; Taylor, Randa; Thomas, Jennifer; Van Fleet, Laduska; Askanazi, David; Fineberg, Naomi; Sun, Yanhui

2012-01-01

Pediatric acute care nurses questioned the practice of weighing disposable infant diapers immediately after voiding. This study asked the research question, "Does volume of saline, diaper configuration, and/or size of diaper statistically effect changes in diaper weights over time?" The method was an experimental, laboratory model. Pre-set volumes of saline were added to disposable diapers that were then left folded or unfolded. Each diaper was weighed immediately post-wetting and re-weighed at hourly intervals for seven hours. Data were analyzed using a repeated measures analysis of variance (RMANOVA) with balanced data (F-test). Diaper weight changes over time were statistically significant for all time points and for all volumes regardless of diaper size; however, the changes in weight were small and without clinical significance. It is appropriate to weigh diapers at the end of eight hours without risk of altering subsequent fluid management of patients in open-air, non-humidified environments. This practice has led to more efficient use of nurses' time with fewer interruptions for patients and families.

A new method of calculation of thyroid weight, using computed tomography

International Nuclear Information System (INIS)

Sugimura, Kazuro; Matsuo, Michimasa; Sugimura, Chie; Nishiyama, Shoji; Narabayashi, Isamu; Kimura, Shuji

1983-01-01

The weight of the thyroid gland is an important factor for determination of dose of the radioactive iodine that is used for the management of hyperthyroidism. Various methods employing scintigraphic image have been employed for estimation of the thyroid weight, but the error by these methods has been greater than 40 per cent. In this study, a new technique has been developed for more accurate estimation of the weight of the thyroid glands employing the distinctive system of three dimensional reconstruction with the simultaneous calculation of the volume of the thyroid using CT images. By this technique, the volume of thyroid phantom could be calculated with lesser than 9.4 per cent error. The proper interval of CT scan was 10 mm for satisfactory measurement. In 18 patients who have undergone thyroidectomy, the thyroid weight that had been estimated by our technique was compared with the actual weight of the excised specimen. There was a satisfactory correlation with 11.3 +- 7.5 per cent error. It has been concluded that our technique provides more accurate estimation of the weight of the thyroid glands than any other methods which have been previously employed. (author)

Averaging in the presence of sliding errors

International Nuclear Information System (INIS)

Yost, G.P.

1991-08-01

In many cases the precision with which an experiment can measure a physical quantity depends on the value of that quantity. Not having access to the true value, experimental groups are forced to assign their errors based on their own measured value. Procedures which attempt to derive an improved estimate of the true value by a suitable average of such measurements usually weight each experiment's measurement according to the reported variance. However, one is in a position to derive improved error estimates for each experiment from the average itself, provided an approximate idea of the functional dependence of the error on the central value is known. Failing to do so can lead to substantial biases. Techniques which avoid these biases without loss of precision are proposed and their performance is analyzed with examples. These techniques are quite general and can bring about an improvement even when the behavior of the errors is not well understood. Perhaps the most important application of the technique is in fitting curves to histograms

Intravascular volume in cirrhosis. Reassessment using improved methodology

International Nuclear Information System (INIS)

Rector, W.G. Jr.; Ibarra, F.

1988-01-01

Previous studies of blood volume (BV) in cirrhosis have either not adjusted BV properly for body size; determined plasma volume from the dilution of labeled albumin 10-20 min postinjection, when some extravascular redistribution has already occurred; and/or not used the correct whole body-peripheral hematocrit ratio (0.82) in calculating whole BV from plasma volume and the peripheral hematocrit. We measured BV with attention to these considerations in 19 patients with cirrhosis and reexamined the determinants of vascular volume and the relationship between vascular volume and sodium retention. BV was calculated as plasma volume (determined from extrapolated plasma activity of intravenously injected [ 131 I]+albumin at time 0) divided by (peripheral hematocrit X 0.82). The result was expressed per kilogram dry body weight, determined by subtracting the mass of ascites (measured by isotope dilution; 1 liter = 1 kg) from the actual body weight of nonedematous patients. Measured and expressed in this way, BV correlated strongly with esophageal variceal size (r = 0.87, P less than 0.05), although not with net portal, right atrial, inferior vena caval, or arterial pressure, and was significantly greater in patients with sodium retention as compared to patients without sodium retention. The principal modifier of vascular volume in cirrhosis is vascular capacity, which is probably mainly determined by the extent of the portasystemic collateral circulation. Increased vascular volume in patients with sodium retention as compared to patients without sodium retention supports the overflow theory of ascites formation

Height and weight distribution of lower-middle income group of radiation workers

International Nuclear Information System (INIS)

Datta, S.; Sharma, R.C.; Sunta, C.M.

1982-01-01

Workers in the nuclear industry who are occasionally exposed to a radioactive environment were monitored for possible internal contamination. Calibration of the detection equipment was carried out with the help of a phantom. It is imperative that the phantom should have the physical dimensions of the subjects being monitored. As a step towards evolving a reference phantom, the height and weight distribution of the workers has been studied. The subjects included in this study are from lower middle income group drawing salaries between Rs 500 to 1000 per month. Mean weight +- SD was found to be 56.2 +- 8.70 kg and height 167 +- 5.90 cm. these averages match well with the data given by certain Life Insurance Companies in India. Although mean weight was found to be appreciably higher than the value reported in 1966, based on autopsy data, the mean weight and height are much less than the reference man values adopted by International Commission on Radiological Protection (ICRP) which are based on western man (average weight = 70 kg., average height = 174 cm). (author)

Average weighted receiving time in recursive weighted Koch networks

Indian Academy of Sciences (India)

Zhenjiang, 212013, People's Republic of China. ∗ ... The properties of a graph can be expressed via its adjacency matrix aij , whose elements take the ... For example, take the worldwide airport networks, where the number of sched- ..... This research is supported by the Humanistic and Social Science Foundation from the.

Actuator disk model of wind farms based on the rotor average wind speed

DEFF Research Database (Denmark)

Han, Xing Xing; Xu, Chang; Liu, De You

2016-01-01

Due to difficulty of estimating the reference wind speed for wake modeling in wind farm, this paper proposes a new method to calculate the momentum source based on the rotor average wind speed. The proposed model applies volume correction factor to reduce the influence of the mesh recognition of ...

Weight change in a commercial web-based weight loss program and its association with website use: cohort study.

Science.gov (United States)

Neve, Melinda; Morgan, Philip J; Collins, Clare E

2011-10-12

There is a paucity of information in the scientific literature on the effectiveness of commercial weight loss programs, including Web-based programs. The potential of Web-based weight loss programs has been acknowledged, but their ability to achieve significant weight loss has not been proven. The objectives were to evaluate the weight change achieved within a large cohort of individuals enrolled in a commercial Web-based weight loss program for 12 or 52 weeks and to describe participants' program use in relation to weight change. Participants enrolled in an Australian commercial Web-based weight loss program from August 15, 2007, through May 31, 2008. Self-reported weekly weight records were used to determine weight change after 12- and 52-week subscriptions. The primary analysis estimated weight change using generalized linear mixed models (GLMMs) for all participants who subscribed for 12 weeks and also for those who subscribed for 52 weeks. A sensitivity analysis was conducted using the last observation carried forward (LOCF) method. Website use (ie, the number of days participants logged on, made food or exercise entries to the Web-based diary, or posted to the discussion forum) was described from program enrollment to 12 and 52 weeks, and differences in website use by percentage weight change category were tested using Kruskal-Wallis test for equality of populations. Participants (n = 9599) had a mean (standard deviation [SD]) age of 35.7 (9.5) years and were predominantly female (86% or 8279/9599) and obese (61% or 5866/9599). Results from the primary GLMM analysis including all enrollees found the mean percentage weight change was -6.2% among 12-week subscribers (n = 6943) and -6.9% among 52-week subscribers (n = 2656). Sensitivity analysis using LOCF revealed an average weight change of -3.0% and -3.5% after 12 and 52 weeks respectively. The use of all website features increased significantly (P Web-based weight loss program is likely to be in the range of

Compositional dependences of average positron lifetime in binary As-S/Se glasses

International Nuclear Information System (INIS)

Ingram, A.; Golovchak, R.; Kostrzewa, M.; Wacke, S.; Shpotyuk, M.; Shpotyuk, O.

2012-01-01

Compositional dependence of average positron lifetime is studied systematically in typical representatives of binary As-S and As-Se glasses. This dependence is shown to be in opposite with molar volume evolution. The origin of this anomaly is discussed in terms of bond free solid angle concept applied to different types of structurally-intrinsic nanovoids in a glass.

Compositional dependences of average positron lifetime in binary As-S/Se glasses

Energy Technology Data Exchange (ETDEWEB)

Ingram, A. [Department of Physics of Opole University of Technology, 75 Ozimska str., Opole, PL-45370 (Poland); Golovchak, R., E-mail: roman_ya@yahoo.com [Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, PA 18015-3195 (United States); Kostrzewa, M.; Wacke, S. [Department of Physics of Opole University of Technology, 75 Ozimska str., Opole, PL-45370 (Poland); Shpotyuk, M. [Lviv Polytechnic National University, 12, Bandery str., Lviv, UA-79013 (Ukraine); Shpotyuk, O. [Institute of Physics of Jan Dlugosz University, 13/15al. Armii Krajowej, Czestochowa, PL-42201 (Poland)

2012-02-15

Compositional dependence of average positron lifetime is studied systematically in typical representatives of binary As-S and As-Se glasses. This dependence is shown to be in opposite with molar volume evolution. The origin of this anomaly is discussed in terms of bond free solid angle concept applied to different types of structurally-intrinsic nanovoids in a glass.

Association of newborn diseases with weight/length ratio and the adequacy of weight for gestational age

Directory of Open Access Journals (Sweden)

José Ricardo Dias Bertagnon

2011-09-01

Full Text Available Objective: To compare the frequencies of newborn diseases in thosenewborns classified according to a weight/length rate and thoseclassified by the adequacy weight for gestational age. Methods: Aretrospective cross-sectional study by record assessment was carriedout enclosing all the live newborns at Hospital Geral do Grajaú, fromSeptember to December, 2009 (n =577 classified according to therate weight/length and also to the adequacy weight for gestationalage. The 10 and 90 percentiles of the weight/length distribution, nowdesignated as “indices” were calculated leading to the followingclassification: low index, for newborns below 54.8 g/cm; high index,for those over 75.8 g/cm; and average index, for the remainingnewborns. According to the adequacy weight for gestational age thenewborns were designated as pre-term for gestational age; term smallfor gestational age; appropriate term and large term. In this samplethere were no small and large pre-term or post-term newborns. Majordiseases were related to the index and adequacy extracts by the χ2test for a contingency table. Results: A significant association wasfound among low index, pre-term for gestational age newborns andterm small for gestational age; between average index and appropriatefor gestational age term newborns; and high index with large termappropriate for gestational age newborns (p< 0.001. Hypoglycemia(3.4% was associated to both low and high indices, to appropriatefor gestational age preterm newborns and to small for gestational ageterm newborns. Sepsis (3.1% was associated to both low index andpre-term appropriate for gestational age newborns. The respiratorydistress syndrome (1.3% was associated to low index and pre-termappropriate for gestational age newborns. Other respiratory distresssyndromes (3.8% were associated to low and high indices but notto the adequacy for gestational age classification. Jaundice (14.9%was not associated to the studied classifications

Automated egg grading system using computer vision: Investigation on weight measure versus shape parameters

Science.gov (United States)

Nasir, Ahmad Fakhri Ab; Suhaila Sabarudin, Siti; Majeed, Anwar P. P. Abdul; Ghani, Ahmad Shahrizan Abdul

2018-04-01

Chicken egg is a source of food of high demand by humans. Human operators cannot work perfectly and continuously when conducting egg grading. Instead of an egg grading system using weight measure, an automatic system for egg grading using computer vision (using egg shape parameter) can be used to improve the productivity of egg grading. However, early hypothesis has indicated that more number of egg classes will change when using egg shape parameter compared with using weight measure. This paper presents the comparison of egg classification by the two above-mentioned methods. Firstly, 120 images of chicken eggs of various grades (A–D) produced in Malaysia are captured. Then, the egg images are processed using image pre-processing techniques, such as image cropping, smoothing and segmentation. Thereafter, eight egg shape features, including area, major axis length, minor axis length, volume, diameter and perimeter, are extracted. Lastly, feature selection (information gain ratio) and feature extraction (principal component analysis) are performed using k-nearest neighbour classifier in the classification process. Two methods, namely, supervised learning (using weight measure as graded by egg supplier) and unsupervised learning (using egg shape parameters as graded by ourselves), are conducted to execute the experiment. Clustering results reveal many changes in egg classes after performing shape-based grading. On average, the best recognition results using shape-based grading label is 94.16% while using weight-based label is 44.17%. As conclusion, automated egg grading system using computer vision is better by implementing shape-based features since it uses image meanwhile the weight parameter is more suitable by using weight grading system.

Brain tumor locating in 3D MR volume using symmetry

Science.gov (United States)

Dvorak, Pavel; Bartusek, Karel

2014-03-01

This work deals with the automatic determination of a brain tumor location in 3D magnetic resonance volumes. The aim of this work is not the precise segmentation of the tumor and its parts but only the detection of its location. This work is the first step in the tumor segmentation process, an important topic in neuro-image processing. The algorithm expects 3D magnetic resonance volumes of brain containing a tumor. The detection is based on locating the area that breaks the left-right symmetry of the brain. This is done by multi-resolution comparing of corresponding regions in left and right hemisphere. The output of the computation is the probabilistic map of the tumor location. The created algorithm was tested on 80 volumes from publicly available BRATS databases containing 3D brain volumes afflicted by a brain tumor. These pathological structures had various sizes and shapes and were located in various parts of the brain. The locating performance of the algorithm was 85% for T1-weighted volumes, 91% for T1-weighted contrast enhanced volumes, 96% for FLAIR and T2-wieghted volumes and 95% for their combinations.

Control of molecular weight distribution in synthesis of poly(2-hydroxyethyl methacrylate) using ultrasonic irradiation.

Science.gov (United States)

Kubo, Masaki; Kondo, Takayuki; Matsui, Hideki; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshikuni

2018-01-01

Poly(2-hydroxyethyl methacrylate) (PHEMA) was synthesized using ultrasonic irradiation without any chemical initiator. The effect of the ultrasonic power intensity on the time course of the conversion to polymer, the number average molecular weight, and the polydispersity were investigated in order to synthesize a polymer with a low molecular weight distribution (i.e., low polydispersity). The conversion to polymer increased with time. A higher ultrasonic power intensity resulted in a faster reaction rate. The number average molecular weight increased during the early stage of the reaction and then gradually decreased with time. A higher ultrasonic intensity resulted in a faster degradation rate of the polymer. The polydispersity decreased with time. This was because the degradation rate of a polymer with a higher molecular weight was faster than that of a polymer with a lower molecular weight. A polydispersity below 1.3 was obtained under ultrasonic irradiation. By changing the ultrasonic power intensity during the reaction, the number average molecular weight can be controlled while maintaining low polydispersity. When the ultrasonic irradiation was halted, the reactions stopped and the number average molecular weight and polydispersity did not change. On the basis of the experimental results, a kinetic model for synthesis of PHEMA under ultrasonic irradiation was constructed considering both polymerization and polymer degradation. The kinetic model was in good agreement with the experimental results for the time courses of the conversion to polymer, the number average molecular weight, and the polydispersity for various ultrasonic power intensities. Copyright © 2017 Elsevier B.V. All rights reserved.

Executive functions predict weight loss in a medically supervised weight loss programme

Science.gov (United States)

Bond, D.; Gunstad, J.; Pera, V.; Rathier, L.; Tremont, G.

2016-01-01

Summary Background Deficits in executive functions are related to poorer weight loss after bariatric surgery; however, less is known about the role that these deficits may play during participation in nonsurgical weight loss programmes. This study examined associations between objectively measured executive functions and weight loss during participation in a medically supervised weight loss programme. Methods Twenty‐three adult patients (age 50.4 ± 15.1, BMI 44.2 ± 8.8, 68% female, 92% White) enrolled in a medically supervised weight loss programme, involving prescription of a very low calorie diet and strategies to change eating and activity behaviours, underwent comprehensive computerized testing of executive functions at baseline. Weight was obtained at baseline and 8 weeks. Demographic and clinical information were obtained through medical chart review. Results Participants lost an average of 9.8 ± 3.4% of their initial body weight at 8 weeks. Fewer correct responses on a set‐shifting task and faster reaction time on a response inhibition task were associated with lower weight loss percentage at 8 weeks after adjusting for age, education and depressive symptoms. There were no associations between performance on tests of working memory or planning and weight loss. Conclusions This study shows that worse performance on a set‐shifting task (indicative of poorer cognitive flexibility) and faster reaction times on a response inhibition test (indicative of higher impulsivity) are associated with lower weight loss among participants in a medically supervised weight loss programme. Pre‐treatment assessment of executive functions may be useful in identifying individuals who may be at risk for suboptimal treatment outcomes. Future research is needed to replicate these findings in larger samples and identify underlying mechanisms. PMID:28090338

MRI and Diffusion-weighted MRI Volumetry for Identification of Complete Tumor Responders After Preoperative Chemoradiotherapy in Patients With Rectal Cancer: A Bi-institutional Validation Study.

Science.gov (United States)

Lambregts, Doenja M J; Rao, Sheng-Xiang; Sassen, Sander; Martens, Milou H; Heijnen, Luc A; Buijsen, Jeroen; Sosef, Meindert; Beets, Geerard L; Vliegen, Roy A; Beets-Tan, Regina G H

2015-12-01

Retrospective single-center studies have shown that diffusion-weighted magnetic resonance imaging (DWI) is promising for identification of patients with rectal cancer with a complete tumor response after neoadjuvant chemoradiotherapy (CRT), using certain volumetric thresholds. This study aims to validate the diagnostic value of these volume thresholds in a larger, independent, and bi-institutional patient cohort. A total of 112 patients with locally advanced rectal cancer (2 centers) treated with a long course of CRT were enrolled. Patients underwent standard T2W-magnetic resonance imaging and DWI, both pre- and post-CRT. Two experienced readers independently determined pre-CRT and post-CRT tumor volumes (cm) on T2W-magnetic resonance image and diffusion-weighted magnetic resonance image by means of freehand tumor delineation. Tumor volume reduction rates (Δvolume) were calculated. Previously determined T2W and DWI threshold values for prevolume, postvolume, and Δvolume were tested to "prospectively" assess their respective diagnostic value in discriminating patients with a complete tumor response from patients with residual tumor. Twenty patients had a complete response. Using the average measurements between the 2 readers, areas under the curve for the pre-/post-/Δvolumes was 0.73/0.82/0.78 for T2W-magnetic resonance imaging and 0.77/0.92/0.86 for DWI, respectively. For T2W-volumetry, sensitivity and specificity using the predefined volume thresholds were 55% and 74% for pre-, 60% and 89% for post-, and 60% and 86% for Δvolume. For DWI volumetry, sensitivity and specificity were 65% and 76% for pre-, 70% and 98% for post-, and 70% and 93% for Δvolume. Previously established DWI volume thresholds can be reproduced with good results. Post-CRT DWI volumetry offers the best results for the detection of patients with a complete response after CRT with an area under the curve of 0.92, sensitivity of 70%, and specificity of 98%.

Volume of the domain visited by N spherical Brownian particles

International Nuclear Information System (INIS)

Berezhkovskii, A.M.

1994-01-01

The average value and variance of the volume of the domain visited in time t by N spherical Brownian particles starting initially at the same point are presented as quadratures of the solutions of simple diffusion problems of the survival of a point Brownian particle in the presence of one and two spherical traps. As an illustration, explicit time dependences are obtained for the average volume in one and three dimensions

Stereological estimates of nuclear volume in normal germ cells and carcinoma in situ of the human testis

DEFF Research Database (Denmark)

Sørensen, Flemming Brandt; Müller, J

1990-01-01

Carcinoma in situ of the testis may appear many years prior to the development of an invasive tumour. Using point-sampled intercepts, base-line data concerning unbiased stereological estimates of the volume-weighted mean nuclear volume (nuclear vV) were obtained in 50 retrospective serial...... testicular biopsies from 10 patients with carcinoma in situ. All but two patients eventually developed an invasive growth. Testicular biopsies from 10 normal adult individuals and five prepubertal boys were included as controls. Nuclear vV in testicular carcinoma in situ was significantly larger than...... that of morphologically normal spermatogonia (2P = 1.0 x 10(-19)), with only minor overlap. Normal spermatogonia from controls had, on average, smaller nuclear vV than morphologically normal spermatogonia in biopsies with ipsi- or contra-lateral carcinoma in situ (2P = 5.2 x 10(-3)). No difference in nuclear vV was found...

3D Volumetry and its Correlation Between Postoperative Gastric Volume and Excess Weight Loss After Sleeve Gastrectomy.

Science.gov (United States)

Hanssen, Andrés; Plotnikov, Sergio; Acosta, Geylor; Nuñez, José Tomas; Haddad, José; Rodriguez, Carmen; Petrucci, Claudia; Hanssen, Diego; Hanssen, Rafael

2018-03-01

The volume of the postoperative gastric remnant is a key factor in excess weight loss (EWL) after sleeve gastrectomy (SG). Traditional methods to estimate gastric volume (GV) after bariatric procedures are often inaccurate; usually conventional biplanar contrast studies are used. Thirty patients who underwent SG were followed prospectively and evaluated at 6 months after the surgical procedure, performing 3D CT reconstruction and gastric volumetry, to establish its relationship with EWL. The gastric remnant was distended with effervescent sodium bicarbonate given orally. Helical CT images were acquired and reconstructed; GV was estimated with the software of the CT device. The relationship between GV and EWL was analyzed. The study allowed estimating the GV in all patients. A dispersion diagram showed an inverse relationship between GV and %EWL. 55.5% of patients with GV ≤ 100 ml had %EWL 25-75% and 38.8% had an %EWL above 75% and patients with GV ≥ 100 ml had an %EWL under 25% (50% of patients) or between 25 and 75% (50% of this group). The Pearson's correlation coefficient was R = 6.62, with bilateral significance (p ≤ .01). The Chi-square result correlating GV and EWL showed a significance of .005 (p ≤ .01). The 3D reconstructions showed accurately the shape and anatomic details of the gastric remnant. 3D volumetry CT scans accurately estimate GV after SG. A significant relationship between GV and EWL 6 months after SG was established, seeming that GV ≥ 100 ml at 6 months of SG is associated with poor EWL.

Analysis and comparison of safety models using average daily, average hourly, and microscopic traffic.

Science.gov (United States)

Wang, Ling; Abdel-Aty, Mohamed; Wang, Xuesong; Yu, Rongjie

2018-02-01

There have been plenty of traffic safety studies based on average daily traffic (ADT), average hourly traffic (AHT), or microscopic traffic at 5 min intervals. Nevertheless, not enough research has compared the performance of these three types of safety studies, and seldom of previous studies have intended to find whether the results of one type of study is transferable to the other two studies. First, this study built three models: a Bayesian Poisson-lognormal model to estimate the daily crash frequency using ADT, a Bayesian Poisson-lognormal model to estimate the hourly crash frequency using AHT, and a Bayesian logistic regression model for the real-time safety analysis using microscopic traffic. The model results showed that the crash contributing factors found by different models were comparable but not the same. Four variables, i.e., the logarithm of volume, the standard deviation of speed, the logarithm of segment length, and the existence of diverge segment, were positively significant in the three models. Additionally, weaving segments experienced higher daily and hourly crash frequencies than merge and basic segments. Then, each of the ADT-based, AHT-based, and real-time models was used to estimate safety conditions at different levels: daily and hourly, meanwhile, the real-time model was also used in 5 min intervals. The results uncovered that the ADT- and AHT-based safety models performed similar in predicting daily and hourly crash frequencies, and the real-time safety model was able to provide hourly crash frequency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Deep gray matter volume loss drives disability worsening in multiple sclerosis

Science.gov (United States)

Prados, Ferran; Brownlee, Wallace J.; Altmann, Daniel R.; Tur, Carmen; Cardoso, M. Jorge; De Angelis, Floriana; van de Pavert, Steven H.; Cawley, Niamh; De Stefano, Nicola; Stromillo, M. Laura; Battaglini, Marco; Ruggieri, Serena; Gasperini, Claudio; Filippi, Massimo; Rocca, Maria A.; Rovira, Alex; Sastre‐Garriga, Jaume; Vrenken, Hugo; Leurs, Cyra E.; Killestein, Joep; Pirpamer, Lukas; Enzinger, Christian; Ourselin, Sebastien; Wheeler‐Kingshott, Claudia A.M. Gandini; Chard, Declan; Thompson, Alan J.; Alexander, Daniel C.; Barkhof, Frederik; Ciccarelli, Olga

2018-01-01

Objective Gray matter (GM) atrophy occurs in all multiple sclerosis (MS) phenotypes. We investigated whether there is a spatiotemporal pattern of GM atrophy that is associated with faster disability accumulation in MS. Methods We analyzed 3,604 brain high‐resolution T1‐weighted magnetic resonance imaging scans from 1,417 participants: 1,214 MS patients (253 clinically isolated syndrome [CIS], 708 relapsing‐remitting [RRMS], 128 secondary‐progressive [SPMS], and 125 primary‐progressive [PPMS]), over an average follow‐up of 2.41 years (standard deviation [SD] = 1.97), and 203 healthy controls (HCs; average follow‐up = 1.83 year; SD = 1.77), attending seven European centers. Disability was assessed with the Expanded Disability Status Scale (EDSS). We obtained volumes of the deep GM (DGM), temporal, frontal, parietal, occipital and cerebellar GM, brainstem, and cerebral white matter. Hierarchical mixed models assessed annual percentage rate of regional tissue loss and identified regional volumes associated with time‐to‐EDSS progression. Results SPMS showed the lowest baseline volumes of cortical GM and DGM. Of all baseline regional volumes, only that of the DGM predicted time‐to‐EDSS progression (hazard ratio = 0.73; 95% confidence interval, 0.65, 0.82; p < 0.001): for every standard deviation decrease in baseline DGM volume, the risk of presenting a shorter time to EDSS worsening during follow‐up increased by 27%. Of all longitudinal measures, DGM showed the fastest annual rate of atrophy, which was faster in SPMS (–1.45%), PPMS (–1.66%), and RRMS (–1.34%) than CIS (–0.88%) and HCs (–0.94%; p < 0.01). The rate of temporal GM atrophy in SPMS (–1.21%) was significantly faster than RRMS (–0.76%), CIS (–0.75%), and HCs (–0.51%). Similarly, the rate of parietal GM atrophy in SPMS (–1.24‐%) was faster than CIS (–0.63%) and HCs (–0.23%; all p values <0.05). Only the atrophy rate in DGM in patients was significantly associated

MR renography : An algorithm for calculation and correction of cortical volume averaging in medullary renographs

NARCIS (Netherlands)

de Priester, JA; den Boer, JA; Giele, ELW; Christiaans, MHL; Kessels, A; Hasman, A; van Engelshoven, JMA

We evaluated a mathematical algorithm for the generation of medullary signal from raw dynamic magnetic resonance (MR) data. Five healthy volunteers were studied. MR examination consisted of a run of 100 TI-weighted coronal scans (gradient echo: TR/TE 11/3.4 msec, flip angle 60 degrees; slice

Associations between body weight and depression, social phobia, insomnia, and self-esteem among Taiwanese adolescents.

Science.gov (United States)

Lee, Jia-In; Yen, Cheng-Fang

2014-12-01

The aims of this cross-sectional study were to examine the associations between body weight and mental health indicators including depression, social phobia, insomnia, and self-esteem among Taiwanese adolescents in Grades 7-12. The body mass index (BMI) of 5254 adolescents was calculated based on self-reported weight and height measurements. Body weight status was determined by the age- and gender-specific International Obesity Task Force reference tables. By using participants of average weight as the reference group, the association between body weight status (underweight, overweight, and obesity) and mental health indicators (depression, social phobia, insomnia, and self-esteem) were examined by using multiple regression analysis. The possible moderating effects of sociodemographic characteristics on the association were also examined. After controlling for the effects of sociodemographic characteristics, both overweight (p self-esteem than did those of average weight; however, no significant differences in depression, social phobia, or insomnia were found between those who were overweight/obese and those of average weight. No significant differences in the four mental health indicators were found between those who were underweight and those of average weight. Sociodemographic characteristics had no moderating effect on the association between body weight and mental health indicators. In conclusion, mental health and school professionals must take the association between overweight/obesity and self-esteem into consideration when approaching the issue of mental health among adolescents. Copyright © 2014. Published by Elsevier Taiwan.

Effect of the Health Tourism weight loss programme on body composition and health outcomes in healthy and excess-weight adults.

Science.gov (United States)

Sagayama, Hiroyuki; Shizuma, Kayoko; Toguchi, Makiko; Mizuhara, Hiroji; Machida, Yukiko; Yamada, Yosuke; Ebine, Naoyuki; Higaki, Yasuki; Tanaka, Hiroaki

2018-05-01

Excess weight loss while minimising fat-free mass (FFM) loss is important for health. Travel is a particular period at risk for weight gain and for which the effects of a short-term intensive weight loss programme have not been studied. Therefore, we studied the effect of a novel, 1-week supervised health travel programme combining high volume, low-to-moderate intensity exercise and energy intake restriction on weight, body composition and health outcomes in adults. Weight was also monitored for 12 weeks after the programme. In all, thirty-six subjects (nineteen men, seventeen women) consisting of sixteen excess-weight (BMI: 27·1 (sd 1·7) kg/m2) and twenty healthy-weight (BMI: 22·3 (sd 1·8) kg/m2) individuals participated. Subjects performed 1 h of slow-paced intermittent jogging three times per d and other leisure activities, whereas consuming only provided foods without water restriction. Body mass significantly decreased from pre- to post-intervention in excess-weight and healthy-weight individuals (-3·5 (sd 1·5) and -3·5 (sd 1·3) %, respectively; PTourism weight loss programme's results indicate that it is a viable option.

Potential for efficient frequency conversion at high average power using solid state nonlinear optical materials

International Nuclear Information System (INIS)

Eimerl, D.

1985-01-01

High-average-power frequency conversion using solid state nonlinear materials is discussed. Recent laboratory experience and new developments in design concepts show that current technology, a few tens of watts, may be extended by several orders of magnitude. For example, using KD*P, efficient doubling (>70%) of Nd:YAG at average powers approaching 100 KW is possible; and for doubling to the blue or ultraviolet regions, the average power may approach 1 MW. Configurations using segmented apertures permit essentially unlimited scaling of average power. High average power is achieved by configuring the nonlinear material as a set of thin plates with a large ratio of surface area to volume and by cooling the exposed surfaces with a flowing gas. The design and material fabrication of such a harmonic generator are well within current technology

Brain structural correlates of reward sensitivity and impulsivity in adolescents with normal and excess weight.

Directory of Open Access Journals (Sweden)

Laura Moreno-López

Full Text Available INTRODUCTION: Neuroscience evidence suggests that adolescent obesity is linked to brain dysfunctions associated with enhanced reward and somatosensory processing and reduced impulse control during food processing. Comparatively less is known about the role of more stable brain structural measures and their link to personality traits and neuropsychological factors on the presentation of adolescent obesity. Here we aimed to investigate regional brain anatomy in adolescents with excess weight vs. lean controls. We also aimed to contrast the associations between brain structure and personality and cognitive measures in both groups. METHODS: Fifty-two adolescents (16 with normal weight and 36 with excess weight were scanned using magnetic resonance imaging and completed the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ, the UPPS-P scale, and the Stroop task. Voxel-based morphometry (VBM was used to assess possible between-group differences in regional gray matter (GM and to measure the putative differences in the way reward and punishment sensitivity, impulsivity and inhibitory control relate to regional GM volumes, which were analyzed using both region of interest (ROI and whole brain analyses. The ROIs included areas involved in reward/somatosensory processing (striatum, somatosensory cortices and motivation/impulse control (hippocampus, prefrontal cortex. RESULTS: Excess weight adolescents showed increased GM volume in the right hippocampus. Voxel-wise volumes of the second somatosensory cortex (SII were correlated with reward sensitivity and positive urgency in lean controls, but this association was missed in excess weight adolescents. Moreover, Stroop performance correlated with dorsolateral prefrontal cortex volumes in controls but not in excess weight adolescents. CONCLUSION: Adolescents with excess weight have structural abnormalities in brain regions associated with somatosensory processing and motivation.

OPERATIONAL DISTRIBUTION OF THE TRAIN TRAFFIC VOLUME ON THE SECTIONS OF RAILWAY OPERATING DOMAIN

Directory of Open Access Journals (Sweden)

G. Ya. Моzolevich

2013-10-01

Full Text Available Purpose. The task of the operational distribution of train traffic volume on the sections of operating domain is the optimization one. It is solved in the operational conditions by the dispatch station. The article sets the problem of formalizing and finding the new ways to solve this urgent problem. Methodology. A new approach to solving the problem of operational distribution of train traffic volume on the sections of the rail network with a choice of routes for all train traffics was proposed. Findings. A study of possible routes for the train traffic handle on the operating domain used for mass freight transportations between Krivyi Rih and Donbas was carried out. The use of the proposed method allowed us to obtain a rational distribution of trains on the rail network sections. Originality. The method of train traffic volume distribution in the network under operational conditions was improved. The method, as opposed to the current one allows one to select the route of separate units handle (according to the criteria of the weighted average cost for 1 ton of cargo. Practical value. The use of the proposed technology of the operational distribution of train traffic volume will increase the efficiency of the railways in general and ensure the competitiveness of rail transportations. The methodology implementation involves the use of railway dispatch station for the automated workplaces with appropriate informational support.

Electrospinning and characterization of polyamide 66 nanofibers with different molecular weights

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Lilia Muller Guerrini

2009-06-01

Full Text Available Polyamide 66 (PA66 nanofibers of different molecular weights were obtained by electrospinning of formic acid solutions. An ionic salt, NaCl, was also added to the solutions to increase the conductivity. PA66 concentrations between 15-17 wt.(%/v and electrical fields between 2.0 and 2.5 kV/cm were the best conditions to produce the smallest nanofibers; however, the addition of NaCl increased the fibers average diameters.The characterization of the fibers was done by scanning electron microscopy (SEM, differential scanning calorimetry (DSC, wide angle X rays diffraction (WAXD and Fourier Transformed Infrared (FTIR. As the molecular weight decreased, the nanofibers average diameters also decreased; however, critical number average and weight average molecular weights were necessary for electrospinning. As the amounts of carboxyl terminal groups (CTG increased, the nanofibers average diameters decreased; however, above CTG's critical values of 8.7 x 10-5 mol.g-1 no electrospinning was possible. The addition of ionic salt increased the electrical conductivity of the solutions and increased the nanofibers' average diameters. By DSC, residual solvent in all the electrospun mats was found; two melting endotherms, one between 248 and 258 °C and the other one between 258 and 267 °C, depending on the sample were also observed. These endotherms were attributed to the melting, re-crystallization and re-melting of the PA66 α-phase. The nanofibers had low % of crystallinity compared to a textile fiber. By WAXS and FTIR, confirmation of the presence of α-phase crystals, of small dimensions and highly imperfect and of a very small amount of β and γ-phases crystals in the nanofibers structure was obtained.

Micro CT based truth estimation of nodule volume

Science.gov (United States)

Kinnard, L. M.; Gavrielides, M. A.; Myers, K. J.; Zeng, R.; Whiting, B.; Lin-Gibson, S.; Petrick, N.

2010-03-01

With the advent of high-resolution CT, three-dimensional (3D) methods for nodule volumetry have been introduced, with the hope that such methods will be more accurate and consistent than currently used planar measures of size. However, the error associated with volume estimation methods still needs to be quantified. Volume estimation error is multi-faceted in the sense that there is variability associated with the patient, the software tool and the CT system. A primary goal of our current research efforts is to quantify the various sources of measurement error and, when possible, minimize their effects. In order to assess the bias of an estimate, the actual value, or "truth," must be known. In this work we investigate the reliability of micro CT to determine the "true" volume of synthetic nodules. The advantage of micro CT over other truthing methods is that it can provide both absolute volume and shape information in a single measurement. In the current study we compare micro CT volume truth to weight-density truth for spherical, elliptical, spiculated and lobulated nodules with diameters from 5 to 40 mm, and densities of -630 and +100 HU. The percent differences between micro CT and weight-density volume for -630 HU nodules range from [-21.7%, -0.6%] (mean= -11.9%) and the differences for +100 HU nodules range from [-0.9%, 3.0%] (mean=1.7%).

Ensemble bayesian model averaging using markov chain Monte Carlo sampling

Energy Technology Data Exchange (ETDEWEB)

Vrugt, Jasper A [Los Alamos National Laboratory; Diks, Cees G H [NON LANL; Clark, Martyn P [NON LANL

2008-01-01

Bayesian model averaging (BMA) has recently been proposed as a statistical method to calibrate forecast ensembles from numerical weather models. Successful implementation of BMA however, requires accurate estimates of the weights and variances of the individual competing models in the ensemble. In their seminal paper (Raftery etal. Mon Weather Rev 133: 1155-1174, 2(05)) has recommended the Expectation-Maximization (EM) algorithm for BMA model training, even though global convergence of this algorithm cannot be guaranteed. In this paper, we compare the performance of the EM algorithm and the recently developed Differential Evolution Adaptive Metropolis (DREAM) Markov Chain Monte Carlo (MCMC) algorithm for estimating the BMA weights and variances. Simulation experiments using 48-hour ensemble data of surface temperature and multi-model stream-flow forecasts show that both methods produce similar results, and that their performance is unaffected by the length of the training data set. However, MCMC simulation with DREAM is capable of efficiently handling a wide variety of BMA predictive distributions, and provides useful information about the uncertainty associated with the estimated BMA weights and variances.

Model averaging in the analysis of leukemia mortality among Japanese A-bomb survivors

International Nuclear Information System (INIS)

Richardson, David B.; Cole, Stephen R.

2012-01-01

Epidemiological studies often include numerous covariates, with a variety of possible approaches to control for confounding of the association of primary interest, as well as a variety of possible models for the exposure-response association of interest. Walsh and Kaiser (Radiat Environ Biophys 50:21-35, 2011) advocate a weighted averaging of the models, where the weights are a function of overall model goodness of fit and degrees of freedom. They apply this method to analyses of radiation-leukemia mortality associations among Japanese A-bomb survivors. We caution against such an approach, noting that the proposed model averaging approach prioritizes the inclusion of covariates that are strong predictors of the outcome, but which may be irrelevant as confounders of the association of interest, and penalizes adjustment for covariates that are confounders of the association of interest, but may contribute little to overall model goodness of fit. We offer a simple illustration of how this approach can lead to biased results. The proposed model averaging approach may also be suboptimal as way to handle competing model forms for an exposure-response association of interest, given adjustment for the same set of confounders; alternative approaches, such as hierarchical regression, may provide a more useful way to stabilize risk estimates in this setting. (orig.)

Radiographic heart-volume estimation in normal cats

International Nuclear Information System (INIS)

Ahlberg, N.E.; Hansson, K.; Svensson, L.; Iwarsson, K.

1989-01-01

Heart volume mensuration was evaluated on conventional radiographs from eight normal cats in different body positions using computed tomography (CT). Heart volumes were calculated from orthogonal thoracic radiographs in ventral and dorsal recumbency and from radiographs exposed with a vertical X-ray beam in dorsal and lateral recumbency using the formula for an ellipsoid body. Heart volumes were also estimated with CT in ventral, dorsal, right lateral and left lateral recumbency. No differences between heart volumes from CT in ventral recumbency and those from CT in right and left lateral recumbency were seen. In dorsal recumbency, however, significantly lower heart volumes were obtained. Heart volumes from CT in ventral recumbency were similar to those from radiographs in ventral and dorsal recumbency and dorsal/left lateral recumbency. Close correlation was also demonstrated between heart volumes from radiographs in dorsal/ left lateral recumbency and body weights of the eight cats

Residual limb fluid volume change and volume accommodation: Relationships to activity and self-report outcomes in people with trans-tibial amputation.

Science.gov (United States)

Sanders, Joan E; Youngblood, Robert T; Hafner, Brian J; Ciol, Marcia A; Allyn, Katheryn J; Gardner, David; Cagle, John C; Redd, Christian B; Dietrich, Colin R

2018-02-01

Fluctuations in limb volume degrade prosthesis fit and require users to accommodate changes using management strategies, such as donning and doffing prosthetic socks. To examine how activities and self-report outcomes relate to daily changes in residual limb fluid volume and volume accommodation. Standardized, two-part laboratory protocol with an interim observational period. Participants were classified as "accommodators" or "non-accommodators," based on self-report prosthetic sock use. Participants' residual limb fluid volume change was measured using a custom bioimpedance analyzer and a standardized in-laboratory activity protocol. Self-report health outcomes were assessed with the Socket Comfort Score and Prosthesis Evaluation Questionnaire. Activity was monitored while participants left the laboratory for at least 3 h. They then returned to repeat the bioimpedance test protocol. Twenty-nine people were enrolled. Morning-to-afternoon percent limb fluid volume change per hour was not strongly correlated to percent time weight-bearing or to self-report outcomes. As a group, non-accommodators ( n = 15) spent more time with their prosthesis doffed and reported better outcomes than accommodators. Factors other than time weight-bearing may contribute to morning-to-afternoon limb fluid volume changes and reported satisfaction with the prosthesis among trans-tibial prosthesis users. Temporary doffing may be a more effective and satisfying accommodation method than sock addition. Clinical relevance Practitioners should be mindful that daily limb fluid volume change and prosthesis satisfaction are not dictated exclusively by activity. Temporarily doffing the prosthesis may slow daily limb fluid volume loss and should be investigated as an alternative strategy to sock addition.

Overweight people have low levels of implicit weight bias, but overweight nations have high levels of implicit weight bias.

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Maddalena Marini

Full Text Available Although a greater degree of personal obesity is associated with weaker negativity toward overweight people on both explicit (i.e., self-report and implicit (i.e., indirect behavioral measures, overweight people still prefer thin people on average. We investigated whether the national and cultural context - particularly the national prevalence of obesity - predicts attitudes toward overweight people independent of personal identity and weight status. Data were collected from a total sample of 338,121 citizens from 71 nations in 22 different languages on the Project Implicit website (https://implicit.harvard.edu/ between May 2006 and October 2010. We investigated the relationship of the explicit and implicit weight bias with the obesity both at the individual (i.e., across individuals and national (i.e., across nations level. Explicit weight bias was assessed with self-reported preference between overweight and thin people; implicit weight bias was measured with the Implicit Association Test (IAT. The national estimates of explicit and implicit weight bias were obtained by averaging the individual scores for each nation. Obesity at the individual level was defined as Body Mass Index (BMI scores, whereas obesity at the national level was defined as three national weight indicators (national BMI, national percentage of overweight and underweight people obtained from publicly available databases. Across individuals, greater degree of obesity was associated with weaker implicit negativity toward overweight people compared to thin people. Across nations, in contrast, a greater degree of national obesity was associated with stronger implicit negativity toward overweight people compared to thin people. This result indicates a different relationship between obesity and implicit weight bias at the individual and national levels.

Comparison of Spot and Time Weighted Averaging (TWA Sampling with SPME-GC/MS Methods for Trihalomethane (THM Analysis

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Don-Roger Parkinson

2016-02-01

Full Text Available Water samples were collected and analyzed for conductivity, pH, temperature and trihalomethanes (THMs during the fall of 2014 at two monitored municipal drinking water source ponds. Both spot (or grab and time weighted average (TWA sampling methods were assessed over the same two day sampling time period. For spot sampling, replicate samples were taken at each site and analyzed within 12 h of sampling by both Headspace (HS- and direct (DI- solid phase microextraction (SPME sampling/extraction methods followed by Gas Chromatography/Mass Spectrometry (GC/MS. For TWA, a two day passive on-site TWA sampling was carried out at the same sampling points in the ponds. All SPME sampling methods undertaken used a 65-µm PDMS/DVB SPME fiber, which was found optimal for THM sampling. Sampling conditions were optimized in the laboratory using calibration standards of chloroform, bromoform, bromodichloromethane, dibromochloromethane, 1,2-dibromoethane and 1,2-dichloroethane, prepared in aqueous solutions from analytical grade samples. Calibration curves for all methods with R2 values ranging from 0.985–0.998 (N = 5 over the quantitation linear range of 3–800 ppb were achieved. The different sampling methods were compared for quantification of the water samples, and results showed that DI- and TWA- sampling methods gave better data and analytical metrics. Addition of 10% wt./vol. of (NH42SO4 salt to the sampling vial was found to aid extraction of THMs by increasing GC peaks areas by about 10%, which resulted in lower detection limits for all techniques studied. However, for on-site TWA analysis of THMs in natural waters, the calibration standard(s ionic strength conditions, must be carefully matched to natural water conditions to properly quantitate THM concentrations. The data obtained from the TWA method may better reflect actual natural water conditions.

Analysis of increasing trend of mortgage volume in the Czech Republic

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Petra Střelcová

2009-01-01

Full Text Available The aim of this paper is an empirical analysis of mortgage volume in the Czech Republic and factors identification of the increasing trend of the mortgage volume in the period from 2001 to 2007. Firstly, analysis of quarterly time series of mortgage volume and average mortgage rate are performed. Consequently, causality between mortgage volume and average mortgage rate is analysed. The morgage rate is the most important factor for economic subjects decision of residential investment. Afterwards, it is analysed causality between mortgage volume and selected factors via multiple regression analysis. Based on this analysis, influencing factors for multiple regression analysis describing mortgage volume are selected. Our empirical analysis validate the causality between mortgage volume and mortgage rate, unemployment rate and price level of real estates. Part of this paper is also economic eduction of causality and estimation of expect progress of mortgage volume especially in connection with present economic and business recession.

Impaired kidney growth in low-birth-weight children

DEFF Research Database (Denmark)

Schmidt, Ida M; Chellakooty, Marla; Boisen, Kirsten A

2005-01-01

BACKGROUND: Low birth weight is an important risk factor for hypertension and unfavorable prognoses of a number of renal diseases. It is also associated with reduced kidney size and nephron number. A differentiation between the effects of low birth weight versus being born premature or small...... for gestational age has, however, not been addressed. METHODS: The influence of weight for gestational age (percentage deviation from expected mean), gestational age, birth weight, and early diet on kidney growth was studied in 178 children born pre- or postmature and/or small or large for gestational age......, comparing them to 717 mature children, birth weight appropriate for gestational age. Kidney size was determined by bilateral ultrasonography measuring length, width and depth, using the equation of an ellipsoid for volume calculation. The examinations were performed at 0, 3, and 18 months of age together...

Diffusion-weighted MRI in cervical cancer

International Nuclear Information System (INIS)

McVeigh, Patrick Z.; Haider, Masoom A.; Syed, Aejaz M.; Milosevic, Michael; Fyles, Anthony

2008-01-01

The purpose was to investigate the potential value of apparent diffusion coefficient (ADC) measurement with MRI in the assessment of cervix cancer. Diffusion-weighted MRI was performed in 47 patients with cervical carcinoma undergoing chemoradiation therapy and 26 normal controls on a 1.5-T system with a b-value of 600 s/mm 2 . FIGO stage, tumor volume, nodal status, interstitial fluid pressure (IFP) and oxygen measurements were recorded. Response was defined as no visible tumor 3-6 months following completion of therapy. The average median ADC (mADC) of cervical carcinomas (1.09±0.20 x 10 -3 mm 2 /s) was significantly lower than normal cervix (2.09±0.46 x 10 -3 mm 2 /s) (P -3 mm 2 /s) compared to T2b (1.21 x 10 -3 mm 2 /s) and T3/T4 (1.10 x 10 -3 mm 2 /s) (P<0.001). In patients with squamous carcinomas the 90th percentile of ADC values was lower in responders than non-responders (P<0.05). Median ADC in cervix carcinoma is significantly lower compared to normal cervix. ADC may have predictive value in squamous tumors, but further long-term study will determine the ultimate clinical utility. (orig.)

Measurement of CSF volume with 3D-FASE MRI

International Nuclear Information System (INIS)

Kanayama, Shoichi; Calderon, A.; Makita, Jun-ichi; Ohara, Yukou; Tsunoda, Akira; Sato, Kiyoshi.

1997-01-01

A noninvasive and fast cerebrospinal fluid (CSF) volume measurement method has been developed using 3D-FASE MRI and a semi-automatic segmentation process. Images with a high CSF/(gray and white matter) ratio (about 10-20) were obtained with a heavily T 2 weighted 3D-FASE sequence. The CSF region was segmented with a region growing method and the volume was calculated from the number of segmented voxels with a signal intensity weighted summation. Total measurement time was about 30 minutes for each study. The errors of the measured volumes were within 10% for the phantom experiments. Intracranial CSF volumes of normal volunteers ranged between about 100 and 200 cc and the ventricle/intracranial CSF ratio was about 10%. 3D display of the segmented intracranial and ventricle CSF regions was also carried out and proved to be useful to understand the anatomy. Increased intracranial and/or ventricle CSF volumes were obtained for a hydrocephalic patient and one patient with probable cerebral atrophy. The results suggest that the developed method could be used for the diagnosis of patients with neurological diseases. (author)

Geometry of lengths, areas, and volumes two-dimensional spaces, volume 1

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Cannon, James W

2017-01-01

This is the first of a three volume collection devoted to the geometry, topology, and curvature of 2-dimensional spaces. The collection provides a guided tour through a wide range of topics by one of the twentieth century's masters of geometric topology. The books are accessible to college and graduate students and provide perspective and insight to mathematicians at all levels who are interested in geometry and topology. The first volume begins with length measurement as dominated by the Pythagorean Theorem (three proofs) with application to number theory; areas measured by slicing and scaling, where Archimedes uses the physical weights and balances to calculate spherical volume and is led to the invention of calculus; areas by cut and paste, leading to the Bolyai-Gerwien theorem on squaring polygons; areas by counting, leading to the theory of continued fractions, the efficient rational approximation of real numbers, and Minkowski's theorem on convex bodies; straight-edge and compass constructions, giving c...

Associations between body weight and depression, social phobia, insomnia, and self-esteem among Taiwanese adolescents

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Jia-In Lee

2014-12-01

Full Text Available The aims of this cross-sectional study were to examine the associations between body weight and mental health indicators including depression, social phobia, insomnia, and self-esteem among Taiwanese adolescents in Grades 7–12. The body mass index (BMI of 5254 adolescents was calculated based on self-reported weight and height measurements. Body weight status was determined by the age- and gender-specific International Obesity Task Force reference tables. By using participants of average weight as the reference group, the association between body weight status (underweight, overweight, and obesity and mental health indicators (depression, social phobia, insomnia, and self-esteem were examined by using multiple regression analysis. The possible moderating effects of sociodemographic characteristics on the association were also examined. After controlling for the effects of sociodemographic characteristics, both overweight (p < 0.05 and obese adolescents (p < 0.001 had a lower level of self-esteem than did those of average weight; however, no significant differences in depression, social phobia, or insomnia were found between those who were overweight/obese and those of average weight. No significant differences in the four mental health indicators were found between those who were underweight and those of average weight. Sociodemographic characteristics had no moderating effect on the association between body weight and mental health indicators. In conclusion, mental health and school professionals must take the association between overweight/obesity and self-esteem into consideration when approaching the issue of mental health among adolescents.

Maternal weight change from prepregnancy to 7 years postpartum

DEFF Research Database (Denmark)

Kirkegaard, Helene; Stovring, Henrik; Rasmussen, Kathleen M

2015-01-01

OBJECTIVE: We studied the influence of maternal behavior on weight change from prepregnancy to 7 years postpartum. METHODS: We used linear regression to study the independent and combined associations between self-reported behavior in pregnancy (dietary intake, leisure-time exercise, sedentary...... activity, smoking) and postpartum (breastfeeding duration and smoking) on weights at 6 months, 18 months, and 7 years postpartum. RESULTS: Women's average 7-year weight gain was 2.07 kg, with 23% gaining >5 kg. Multivariable analyses suggested that women with healthier dietary intake, more leisure......-time exercise, less sedentary behavior, and longer duration of breastfeeding on average gained 1.66 kg [95% confidence interval (CI): 1.40; 1.91] with a significantly reduced odds [OR 0.56 (95% CI: 0.49; 0.64)] of gaining >5 kg from prepregnancy to 7 years postpartum compared to women with none or one...

Average fetal depth in utero: data for estimation of fetal absorbed radiation dose

International Nuclear Information System (INIS)

Ragozzino, M.W.; Breckle, R.; Hill, L.M.; Gray, J.E.

1986-01-01

To estimate fetal absorbed dose from radiographic examinations, the depth from the anterior maternal surface to the midline of the fetal skull and abdomen was measured by ultrasound in 97 pregnant women. The relationships between fetal depth, fetal presentation, and maternal parameters of height, weight, anteroposterior (AP) thickness, gestational age, placental location, and bladder volume were analyzed. Maternal AP thickness (MAP) can be estimated from gestational age, maternal height, and maternal weight. Fetal midskull and abdominal depths were nearly equal. Fetal depth normalized to MAP was independent or nearly independent of maternal parameters and fetal presentation. These data enable a reasonable estimation of absorbed dose to fetal brain, abdomen, and whole body

State Averages

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U.S. Department of Health & Human Services — A list of a variety of averages for each state or territory as well as the national average, including each quality measure, staffing, fine amount and number of...

Ovarian volume throughout life

DEFF Research Database (Denmark)

Kelsey, Thomas W; Dodwell, Sarah K; Wilkinson, A Graham

2013-01-01

conception to 82 years of age. This model shows that 69% of the variation in ovarian volume is due to age alone. We have shown that in the average case ovarian volume rises from 0.7 mL (95% CI 0.4-1.1 mL) at 2 years of age to a peak of 7.7 mL (95% CI 6.5-9.2 mL) at 20 years of age with a subsequent decline...... to about 2.8 mL (95% CI 2.7-2.9 mL) at the menopause and smaller volumes thereafter. Our model allows us to generate normal values and ranges for ovarian volume throughout life. This is the first validated normative model of ovarian volume from conception to old age; it will be of use in the diagnosis......The measurement of ovarian volume has been shown to be a useful indirect indicator of the ovarian reserve in women of reproductive age, in the diagnosis and management of a number of disorders of puberty and adult reproductive function, and is under investigation as a screening tool for ovarian...

Bladder volume variations of cervical cancer patient in radiation therapy using ultrasonography

Energy Technology Data Exchange (ETDEWEB)

Gong, Jong Ho [Dept. of Radiation Oncology, Pusan National University Hospital, Pusan (Korea, Republic of)

2016-12-15

The bladder volume change was measured using ultrasonography for helping decrease the side effects and other organ variations in the location of radiation therapy for cervical cancer patients. An experiment was performed targeting patients who were treated with radiation therapy at PNUH within the period from September to December 2015. To maintain the bladder volume, each patient was instructed to drink 500 cc water before and after CT simulation, 60 minutes before the dry run. Also, the bladder volume was measured in each patient CT scan, and a 3D conformal therapy plan was designed. The bladder volumes measured before and after the CT simulation, dry run, and radiation treatment planning were compared and analyzed. The average volume and average error of the bladder that were obtained from the measurement based on the CT scan images had the lowest standard deviation in the CT simulation. This means that the values that were obtained before and after the CT simulation were statistically relevant and correlative. Moreover, the bladder volume measured via ultrasonography was larger size, the average volume in the CT scan. But the values that were obtained Dry run and after the CT simulation were not statistically relevant. Drinking a certain amount of water helps a patient maintain his/her bladder volume for a dry run. Even then, it is difficult to maintain the bladder volume for the dry run. Also, whether or not the patients followed the directions for the dry run correctly is important.

Weight loss in orthognathic surgery: a clinical study.

Science.gov (United States)

Hammond, Douglas; Williams, Rhodri W; Juj, Kiranjit; O'Connell, Susan; Isherwood, Grant; Hammond, Nichola

2015-09-01

To analyse weight change, body composition change and Body Mass Index change in patients undergoing orthognathic surgery. A service evaluation was undertaken in orthognathic patients pre-operatively and at 4 weeks post-surgery. Queen Elizabeth Hospital Birmingham outpatient department. Thirty-one patients scheduled for single- or two-jaw orthognathic surgery and rigid internal fixation. Immediately pre-operatively and at 4 weeks post-surgery the following information was gathered: (1) patient height; (2) patient weight (kg); (3) Patient Body Mass Index; and (4) patient body fat percentage. In the 4-week post-operative period, the average weight loss was -4·96 kg (range: -9·6 to +3·0 kg), with a body fat reduction of -3·07% (range: -5·80% to +2·30%) and an average reduction in Body Mass Index of -1·63 (range: -3·4 to +0·8). There was no statistically significant difference in weight loss (P = 0·1562) or body fat composition change (P = 0·2391) between single- or two-jaw surgery. There was no statistically significant difference in weight loss (P = 0·4858) or body fat composition change (P = 0·5321) between male and female patients. Weight loss observed was similar to that reported in studies using inter-maxillary fixation. Closer psychological and dietetic support is needed for patients who have a low normal or underweight Body Mass Index. Better and more bespoke tailored Oral Nutritional Supplementation must be provided for all orthognathic surgery patients to potentially reduce this significant weight loss.

Effects of heavy weight waste glass recycled as fine aggregate on the mechanical properties of mortar specimens

International Nuclear Information System (INIS)

Choi, So Yeong; Choi, Yoon Suk; Yang, Eun Ik

2017-01-01

Highlights: • The properties of mortar used heavy weight waste glass as fine aggregate were compared. • Unit volume weight and shielding performance increased with the content of waste glass. • However, the strength decreased as the waste glass substitution increased. • The waste glass substitution affected on pores ranging from 10–100 nm. - Abstract: The quantities of heavy weight waste glass have increased over time due to rapid industrialization and changes in the quality of life. Moreover, most of this waste is not recycled. Concrete is the most widely used construction material, the huge amounts of natural resources are required to make concrete. Therefore, it is necessary to investigate the possibility of recycling of heavy weight waste glass as an ingredient in the manufacturing of concrete. In this study, the suitability of heavy weight waste glass as a fine aggregate material is considered. The results of flow test, unit volume weight, radiation shielding performance, compressive strength, flexural strength, and micropore and macropore distribution of mortar are compared and evaluated. It was found that when the heavy weight waste glass substitution ratio increases, the fluidity, unit volume weight and radiation shielding performance also increase. However, the compressive and flexural strength of mortar gradually decrease with an increase in the substitution ratio of heavy weight waste glass. Moreover, the micro pore size distribution is significantly affected by the substitution of heavy weight waste glass.

Bayesian Model Averaging of Artificial Intelligence Models for Hydraulic Conductivity Estimation

Science.gov (United States)

Nadiri, A.; Chitsazan, N.; Tsai, F. T.; Asghari Moghaddam, A.

2012-12-01

This research presents a Bayesian artificial intelligence model averaging (BAIMA) method that incorporates multiple artificial intelligence (AI) models to estimate hydraulic conductivity and evaluate estimation uncertainties. Uncertainty in the AI model outputs stems from error in model input as well as non-uniqueness in selecting different AI methods. Using one single AI model tends to bias the estimation and underestimate uncertainty. BAIMA employs Bayesian model averaging (BMA) technique to address the issue of using one single AI model for estimation. BAIMA estimates hydraulic conductivity by averaging the outputs of AI models according to their model weights. In this study, the model weights were determined using the Bayesian information criterion (BIC) that follows the parsimony principle. BAIMA calculates the within-model variances to account for uncertainty propagation from input data to AI model output. Between-model variances are evaluated to account for uncertainty due to model non-uniqueness. We employed Takagi-Sugeno fuzzy logic (TS-FL), artificial neural network (ANN) and neurofuzzy (NF) to estimate hydraulic conductivity for the Tasuj plain aquifer, Iran. BAIMA combined three AI models and produced better fitting than individual models. While NF was expected to be the best AI model owing to its utilization of both TS-FL and ANN models, the NF model is nearly discarded by the parsimony principle. The TS-FL model and the ANN model showed equal importance although their hydraulic conductivity estimates were quite different. This resulted in significant between-model variances that are normally ignored by using one AI model.

Assessment of Fetal Kidney Growth and Birth Weight in an Indigenous Australian Cohort

Directory of Open Access Journals (Sweden)

Christopher J. Diehm

2018-01-01

Full Text Available Introduction: Indigenous Australians experience higher rates of renal disease and hypertension than non-Indigenous Australians. Low birth weight is recognized as a contributing factor in chronic disease and has been shown to increase the risk of renal failure in adulthood. A smaller kidney volume with fewer nephrons places an individual at risk of hypertension and renal failure. Indigenous Australians have fewer nephrons than non-Indigenous Australians. In this study, intrauterine fetal and kidney growth were evaluated in 174 Indigenous Australian babies throughout gestation in order to record and evaluate fetal growth and kidney size, within a population that is at high risk for chronic illness.Methods: Pregnant women that identified as Indigenous, or non-Indigenous women that were pregnant with a partner who identified as an Indigenous Australian were eligible to participate. Maternal history, smoking status, blood and urine samples and fetal ultrasounds were collected throughout pregnancy. Fetal kidney measurements were collected using ultrasound. Statistical analysis was performed using the Stata 14.1 software package.Results: 15.2% of babies were born prematurely. 44% of the mothers reported smoking in pregnancy. The median birth weight of this cohort was 3,240 g. Male fetuses had higher kidney to body weight ratios than female fetuses (P = 0.02. The birth weights of term neonates whose mothers smoked during pregnancy were lower (327 g, P < 0.001 than the birth weights of term babies from non-smoking mothers. The kidney volumes of babies whose mothers smoked were also smaller (P = 0.02, but were in proportion to body weight.Conclusion: In this cohort of Indigenous women smoking was associated with both increased number of preterm births and with a reduction in birth weights, even of term infants. Since kidney volume is a surrogate measure of nephron number and nephrogenesis is complete at birth, babies whose mothers smoked during pregnancy

Depression, posttraumatic stress disorder, and grade point average among student servicemembers and veterans.

Science.gov (United States)

Bryan, Craig J; Bryan, AnnaBelle O; Hinkson, Kent; Bichrest, Michael; Ahern, D Aaron

2014-01-01

The current study examined relationships among self-reported depression severity, posttraumatic stress disorder (PTSD) symptom severity, and grade point average (GPA) among student servicemembers and veterans. We asked 422 student servicemembers and veterans (72% male, 86% Caucasian, mean age = 36.29 yr) to complete an anonymous online survey that assessed self-reported GPA, depression severity, PTSD severity, and frequency of academic problems (late assignments, low grades, failed exams, and skipped classes). Female respondents reported a slightly higher GPA than males (3.56 vs 3.41, respectively, p = 0.01). Depression symptoms (beta weight = -0.174, p = 0.03), male sex (beta weight = 0.160, p = 0.01), and younger age (beta weight = 0.155, p = 0.01) were associated with lower GPA but not PTSD symptoms (beta weight = -0.040, p = 0.62), although the interaction of depression and PTSD symptoms showed a nonsignificant inverse relationship with GPA (beta weight = -0.378, p = 0.08). More severe depression was associated with turning in assignments late (beta weight = 0.171, p = 0.03), failed exams (beta weight = 0.188, p = 0.02), and skipped classes (beta weight = 0.254, p = 0.01). The relationship of depression with self-reported GPA was mediated by frequency of failed examns. Results suggest that student servicemembers and veterans with greater emotional distress also report worse academic performance.

16 CFR 500.8 - Units of weight or mass and measure.

Science.gov (United States)

2010-01-01

...) Statements of weight or mass shall be in terms of both avoirdupois pound and ounce and SI metric kilograms... be in terms of both the U.S. gallon of 231 cubic inches and quart, pint, and fluid ounce subdivisions... the declaration shall express the volume at 60 ° Fahrenheit (15.6 ° Celsius)) express the volume at 68...

The rationale and technique of staged-volume arteriovenous malformation radiosurgery

International Nuclear Information System (INIS)

Pollock, Bruce E.; Kline, Robert W.; Stafford, Scott L.; Foote, Robert L.; Schomberg, Paula J.

2000-01-01

Purpose: Stereotactic radiosurgery is an effective management strategy for properly selected arteriovenous malformation (AVM) patients. However, the risk of postradiosurgical radiation-related injury generally limits this procedure to patients with AVMs of an average diameter of 3 cm or less. Radiosurgery of large AVMs in a planned staged fashion was undertaken to limit the radiation exposure to the surrounding normal brain. Methods and Materials: Between April 1997 and December 1999, 10 patients with a median AVM volume of 17.4 cm 3 (range, 7.4-53.3 cm 3 ) underwent staged-volume radiosurgery (23 procedures). At the first radiosurgical procedure, the total volume of the AVM is estimated and a dose plan calculated that covers 10 cm 3 -15 cm 3 , or one-half the nidus volume if the AVM is critically located (brainstem, thalamus, or basal ganglia). At 6-month intervals thereafter, radiosurgery was repeated to different portions of the AVM with the previous dose plan(s) being re-created utilizing intracranial landmarks to minimize radiation overlap. Radiosurgical procedures were continued until the entire malformation has been irradiated. Results: The radiation dosimetry of staged-volume AVM radiosurgery was compared to hypothetical single-session procedures for the 10 patients. Staged-volume radiosurgery decreased the 12-Gy volume by an average of 11.1% (range, 4.9-21%) (p < 0.001). The non-AVM 12-Gy volume was reduced by an average of 27.2% (range, 12.5-51.3%) (p < 0.001). Discussion: Staged-volume radiosurgery of large AVMs results in less radiation exposure to the adjacent brain. Further follow-up is needed to determine whether this technique provides a high rate of AVM obliteration while maintaining an acceptable rate of radiation-related complications

The architecture design of a 2mW 18-bit high speed weight voltage type DAC based on dual weight resistance chain

Science.gov (United States)

Qixing, Chen; Qiyu, Luo

2013-03-01

At present, the architecture of a digital-to-analog converter (DAC) in essence is based on the weight current, and the average value of its D/A signal current increases in geometric series according to its digital signal bits increase, which is 2n-1 times of its least weight current. But for a dual weight resistance chain type DAC, by using the weight voltage manner to D/A conversion, the D/A signal current is fixed to chain current Icha; it is only 1/2n-1 order of magnitude of the average signal current value of the weight current type DAC. Its principle is: n pairs dual weight resistances form a resistance chain, which ensures the constancy of the chain current; if digital signals control the total weight resistance from the output point to the zero potential point, that could directly control the total weight voltage of the output point, so that the digital signals directly turn into a sum of the weight voltage signals; thus the following goals are realized: (1) the total current is less than 200 μA (2) the total power consumption is less than 2 mW; (3) an 18-bit conversion can be realized by adopting a multi-grade structure; (4) the chip area is one order of magnitude smaller than the subsection current-steering type DAC; (5) the error depends only on the error of the unit resistance, so it is smaller than the error of the subsection current-steering type DAC; (6) the conversion time is only one action time of switch on or off, so its speed is not lower than the present DAC.

The architecture design of a 2mW 18-bit high speed weight voltage type DAC based on dual weight resistance chain

International Nuclear Information System (INIS)

Chen Qixing; Luo Qiyu

2013-01-01

At present, the architecture of a digital-to-analog converter (DAC) in essence is based on the weight current, and the average value of its D/A signal current increases in geometric series according to its digital signal bits increase, which is 2 n−1 times of its least weight current. But for a dual weight resistance chain type DAC, by using the weight voltage manner to D/A conversion, the D/A signal current is fixed to chain current I cha ; it is only 1/2 n−1 order of magnitude of the average signal current value of the weight current type DAC. Its principle is: n pairs dual weight resistances form a resistance chain, which ensures the constancy of the chain current; if digital signals control the total weight resistance from the output point to the zero potential point, that could directly control the total weight voltage of the output point, so that the digital signals directly turn into a sum of the weight voltage signals; thus the following goals are realized: (1) the total current is less than 200 μA; (2) the total power consumption is less than 2 mW; (3) an 18-bit conversion can be realized by adopting a multi-grade structure; (4) the chip area is one order of magnitude smaller than the subsection current-steering type DAC; (5) the error depends only on the error of the unit resistance, so it is smaller than the error of the subsection current-steering type DAC; (6) the conversion time is only one action time of switch on or off, so its speed is not lower than the present DAC. (semiconductor integrated circuits)

Development skills of children born premature with low and very low birth weight.

Science.gov (United States)

Ribeiro, Camila da Costa; Pachelli, Mariane Regina de Oliveira; Amaral, Natalie Camillo de Oliveira; Lamônica, Dionísia Aparecida Cusin

2017-01-30

To compare the performance of children born premature with low birth weight (LBW) and very low birth-weight (VLBW) with that of children born at term, within the age range of one to three years, regarding child development in the gross motor, fine motor-adaptive, personal-social and language domains. This is a cross-sectional study in a cohort of 150 infants born premature (experimental group) and at term (control group) divided into eight groups with respect to weight (low birth weight: motor, fine motor-adaptive, personal-social and language domains. In this study, the preterm groups presented different performances, i.e., normative, average, and below average performances were observed within the same group.

Method for sampling and analysis of volatile biomarkers in process gas from aerobic digestion of poultry carcasses using time-weighted average SPME and GC-MS.

Science.gov (United States)

Koziel, Jacek A; Nguyen, Lam T; Glanville, Thomas D; Ahn, Heekwon; Frana, Timothy S; Hans van Leeuwen, J

2017-10-01

A passive sampling method, using retracted solid-phase microextraction (SPME) - gas chromatography-mass spectrometry and time-weighted averaging, was developed and validated for tracking marker volatile organic compounds (VOCs) emitted during aerobic digestion of biohazardous animal tissue. The retracted SPME configuration protects the fragile fiber from buffeting by the process gas stream, and it requires less equipment and is potentially more biosecure than conventional active sampling methods. VOC concentrations predicted via a model based on Fick's first law of diffusion were within 6.6-12.3% of experimentally controlled values after accounting for VOC adsorption to the SPME fiber housing. Method detection limits for five marker VOCs ranged from 0.70 to 8.44ppbv and were statistically equivalent (p>0.05) to those for active sorbent-tube-based sampling. The sampling time of 30min and fiber retraction of 5mm were found to be optimal for the tissue digestion process. Copyright © 2017 Elsevier Ltd. All rights reserved.

26 CFR 48.4071-2 - Determination of weight.

Science.gov (United States)

2010-04-01