Good Degree Of Agreement Research Articles

Modelling the non-equilibrium two-phase flow during depressurisation of CO2 pipelines

The development, testing and validation of a two-fluid transient flow model for simulating outflow following the failure of high pressure CO2 pipelines is presented. Thermal and mechanical non-equilibrium effects during depressurisation are accounted for by utilising simple constitutive relations describing inter-phase mass, heat and momentum transfer in terms of relaxation to equilibrium. Pipe wall/fluid heat exchange on the other hand is modelled by coupling the fluid model with a finite difference transient heat conduction model. The two-fluid transient flow model's performance is tested by comparison of the predicted transient pressure and temperature profiles along the pipeline against those based on the simplified homogeneous equilibrium model (HEM) as well as real data captured during the full bore rupture of a 260m long, 233mm internal diameter pipeline containing CO2 at 36bara and 273°C. The two-fluid model is found to produce a reasonably good degree of agreement with the experimental data throughout the depressurisation process. The HEM based flow model on the other hand performs well only near the rupture plane and during the early stages of the depressurisation process.

A vector auto-regressive model for onshore and offshore wind synthesis incorporating meteorological model information

Abstract. The growth of wind power production in the electricity portfolio is striving to meet ambitious targets set, for example by the EU, to reduce greenhouse gas emissions by 20% by 2020. Huge investments are now being made in new offshore wind farms around UK coastal waters that will have a major impact on the GB electrical supply. Representations of the UK wind field in syntheses which capture the inherent structure and correlations between different locations including offshore sites are required. Here, Vector Auto-Regressive (VAR) models are presented and extended in a novel way to incorporate offshore time series from a pan-European meteorological model called COSMO, with onshore wind speeds from the MIDAS dataset provided by the British Atmospheric Data Centre. Forecasting ability onshore is shown to be improved with the inclusion of the offshore sites with improvements of up to 25% in RMS error at 6 h ahead. In addition, the VAR model is used to synthesise time series of wind at each offshore site, which are then used to estimate wind farm capacity factors at the sites in question. These are then compared with estimates of capacity factors derived from the work of Hawkins et al. (2011). A good degree of agreement is established indicating that this synthesis tool should be useful in power system impact studies.

Fracture micromechanisms and mechanical behavior of YBCO bulk superconductors at 77 and 300 K

In this study two YBa2Cu3O7−δ bulk superconductors were evaluated, with the aim of analyzing the influence of the processing method (TSMG and Bridgman) and the test temperature on their mechanical behavior. The relationship between their mechanical properties and fracture micromechanisms has also been studied. Both materials were tested at room and at service temperature. TPB tests were carried out to determine their mechanical behavior, strength and toughness. Moreover, one of the two materials, characterized by transversal microstructural anisotropy, was tested in two directions. Hardness of both materials at nano and micro scale was studied. The results show that the mechanical behavior of the materials is controlled by the defects and cracks that have been introduced during the processing of the materials. A good degree of agreement was found between the experimental crack defects detected by means of SEM and those gathered from the fracture mechanical analysis of the experimental data.

Tracking Navigation Imaging of Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma Using Three-Dimensional Cone-Beam CT Angiography

Purpose: New tracking navigation imaging software was used to evaluate the usefulness of three dimensional (3D) CT angiography for transcatheter arterial chemoembolization (TACE) in patients with hepatocellular carcinoma (HCC). Materials and Methods: Fifty-two patients with 73 HCCs were enrolled in this study retrospectively. Rotational angiography was performed from the hepatic artery for evaluation of the tumor feeding vessels. Arteries feeding the tumor were traced automatically by adjusting the region of interest around the targeted tumor on axial and coronal images using tracking navigation imaging with 3D cone-beam CT angiography. Results: Using final selective angiographic findings as the gold standard, the detection of feeding vessels was 90.4% (66/73) for tracking navigation imaging and 50.7% (37/73) for celiac trunk angiography. This difference was statistically significant (Wilcoxon rank sum test, p < 0.001). The sensitivity, specificity, positive predictive value, and negative predictive value for the detection of feeding arteries were 97.1% (66/68), 80.0% (4/5), 98.5% (66/67), and 66.7% (4/6), respectively. The kappa coefficient had a value of 0.638 (95% CI: 0.471-0.805), which is considered to indicate a good degree of agreement. With the assistance of tracking navigation imaging, the disease control rate of TACE for HCC was 67.3% (35/52) according to the modified Response Evaluation Criteria in Solid Tumors. During follow-up periods of 1-11 months, 10 patients (19.2%) remained cancer-free after TACE. Conclusion: Tracking navigation imaging with 3D cone-beam CT angiography should be useful for TACE in HCC patients with complicated feeding arteries.

Fetal magnetic resonance imaging and neurosonography in congenital neurological anomalies: supplementary diagnostic and postnatal prognostic value

Objective: To compare the diagnostic conclusions between fetal neurosonography and MRI in the cases of congenital neurological abnormalities, and with postnatal clinical and imaging evaluation, when available.Methods: A retrospective study of 28 patients who underwent a fetal MRI study for suspected congenital neurological anomalies. The diagnoses obtained by neurosonography and MRI were collected and compared. Both of them were compared with the final diagnosis when available by necropsy or postnatal evaluation. Postnatal imaging tests were performed only when clinically indicated.Results: The indications for the fetal MRI examination were: fetal ventriculomegaly, posterior fossa anomalies, suspected midline defects, small-for-gestational-age cephalic biometry and confirmed congenital CMV infection. There was a good degree of agreement beyond chance between both techniques (kappa test = 0.76).Conclusions: Both imaging modalities give a high-diagnostic performance with a good degree of agreement between them, when made by specialized staff. Fetal MRI is a valuable complementary tool to detailed neurosonography which allows an evaluation of the normal brain maturation from the second trimester. It also offers a higher diagnostic performance for some congenital abnormalities such as cortical development or acquired lesions.

PathAct: a novel method for pathway analysis using gene expression profiles

We developed PathAct, a novel method for pathway analysis to investigate the biological and clinical implications of the gene expression profiles. The advantage of PathAct in comparison with the conventional pathway analysis methods is that it can estimate pathway activity levels for individual patient quantitatively in the form of a pathway-by-sample matrix. This matrix can be used for further analysis such as hierarchical clustering and other analysis methods. To evaluate the feasibility of PathAct, comparison with frequently used gene-enrichment analysis methods was conducted using two public microarray datasets. The dataset #1 was that of breast cancer patients, and we investigated pathways associated with triple-negative breast cancer by PathAct, compared with those obtained by gene set enrichment analysis (GSEA). The dataset #2 was another breast cancer dataset with disease-free survival (DFS) of each patient. Contribution by each pathway to prognosis was investigated by our method as well as the Database for Annotation, Visualization and Integrated Discovery (DAVID) analysis. In the dataset #1, four out of the six pathways that satisfied p < 0.05 and FDR < 0.30 by GSEA were also included in those obtained by the PathAct method. For the dataset #2, two pathways (“Cell Cycle” and “DNA replication”) out of four pathways by PathAct were commonly identified by DAVID analysis. Thus, we confirmed a good degree of agreement among PathAct and conventional methods. Moreover, several applications of further statistical analyses such as hierarchical cluster analysis by pathway activity, correlation analysis and survival analysis between pathways were conducted.

A numerical 2D simulation of part motion in vibratory bowl feeders by discrete element method

Vibratory bowl feeder is known as one of the major machines in automatic assembly. The feeding parts in a vibratory bowl feeder are experiencing repeated impacts with friction that can be considered as a typical non-linear dynamic problem. In this paper, a 2D numerical model based on discrete element method has been developed to perform a more accurate investigation on the dynamic behavior of a feeding part. In contrast to previous researches, it was assumed that the feeding part was not a point mass, instead, a rectangular shape that can rotate and have three degrees of freedom. By performing the simulation for various vibration amplitudes, a good degree of agreement was observed between calculated data and the experimental data reported in the literature. It was shown that, depending on the vibration amplitude, the graph of mean conveying velocity versus amplitude was composed of three distinct regions. It was found that while the coefficient of friction mostly affects the conveying velocity in sliding regime, it did not have a significant effect on the conveying velocity after a critical point in hopping regime. The mean conveying velocity was dependent on the part shape and vibration angle. The proposed model is capable of demonstrating both the periodic and chaotic behavior of the feeding part.

A Kit to Facilitate and Standardize the Processing of Sputum for Measurements of Airway Inflammation

The use of inflammometry has been shown to be effective for managing asthma. However, sputum processing can be time consuming. Furthermore, methods of sputum processing can vary among facilities. To help with standardization and to simplify the procedure for laboratory staff, a novel, commercially available processing device (Accufilter, Cellometrics Inc, Canada) has been developed. To assess the validity of the Accufilter device and kit for recovery of treated specimens, and for quantitative sputum inflammatory cell counts by comparing intrasample measurements with those using the same procedure without the Accufilter device and kit. The present study was a wet laboratory comparison of induced sputum cell counts obtained from sputum processed with versus without the device and kit. Comparisons of each sputum specimen were performed by the same technologist in random order. A total of 39 samples were processed using both the standard method and the Accufilter device. The intraclass correlation coefficients were high for the weight of the filtrate, and for eosinophil and neutrophil differential counts. A good degree of agreement of results was apparent when the two methods were compared. The differences noted between both methods were minimal and did not modify clinical interpretation. The use of the Accufilter device and kit can be used in place of the standard method for sputum quantitative analysis, especially in centres with large sample loads.

Rapid detection of human and canine visceral leishmaniasis: Assessment of a latex agglutination test based on the A2 antigen from amastigote forms of Leishmania infantum

The diagnosis of visceral leishmaniasis (VL) in humans and animal reservoir hosts is difficult, particularly in rural areas where the disease is endemic and laboratory facilities are limited. This study aimed to develop a latex agglutination test (LAT) for the rapid detection of anti-Leishmania antibodies against the A2 antigen derived from the amastigote form as well as those against crude antigens derived from the promastigote form of an Iranian strain of Leishmania (Leishmania) infantum. The A2 antigen (42-100 kDa) was prepared from the amastigote form of L. infantum, purified with electroelution and compared with the crude antigen from the promastigote form of L. infantum. Both antigens showed appropriate intensity reactions, were selected using dot blotting of positive and negative pooled sera and used to sensitize 0.9-μm latex beads. The tests were carried out on sera from 43 symptomatic, human patients with VL confirmed by parasitological examination and direct agglutination test (DAT), 30 healthy controls and 32 patients with other infections but without VL. Canine sera were collected from 63 domestic dogs with VL confirmed using parasitological examinations and DAT and 31 healthy dogs from areas non-endemic for VL. Compared with the controls, human sera from DAT-confirmed patients yielded a sensitivity of 88.4% (95% CI, 82.1-94.5%) and specificity of 93.5% (95% CI, 87.0-99.7%) on A2-LAT (amastigote) when 1:3200 was used as the cut-off titre. A good degree of agreement was found between A2-LAT and DAT (0.914). LAT required 3-5 min to complete, versus the 12-18 h needed for DAT. Compared with the controls, A2-LAT of canine sera from DAT-confirmed cases yielded a sensitivity of 95.2% (95% CI, 95.0-95.4%) and specificity of 100% (95% CI 100%) when 1:320 was used as the cut-off titre. A good degree of agreement was found between A2-LAT and DAT (0.968). Similarly, the sensitivity and specificity of Pro.-LAT (promastigote) was calculated to be 88.4% and 91.9%, respectively for human sera and 96.8% and 90.3%, respectively for canine sera. No statistically significant differences were observed between A2-LAT and Pro.-LAT for the detection of human and canine L. infantum infections. In conclusion, A2-LAT and Pro.-LAT could be used in parallel to screen for L. infantum infections in humans and dogs in areas endemic for VL in Iran.

Automated Marking of Sleep Spindles using Wavelet Packet Decomposition and Peak Tracking

Sleep spindles, along with K-complexes are hallmarks of stage 2 non rapid eye movement (NREM) sleep EEG. Sleep spindles are of significant interest because they are associated with phenomena such as ‘stability’ of sleep, updating of knowledge with new memories, processing of sensorimotor and mnemonic information. Therefore, accurately marking their presence in sleep recordings is essential. Accurate identification of spindles in EEG recordings has proved to be a time consuming task, even with the help of experts. Further, manual detection by different experts introduces disparity and biases due to inter-rater differences. Hence there is a crucial need for an automated detection algorithm. The objective of this paper was to develop a robust algorithm for real-time automated spindle detection based on the wavelet packet decomposition. The developed algorithm replicates the marking methodology used by sleep specialists to identify spindles. Spindles are transient 11–16 Hz oscillations present in NREM with higher amplitude than the background delta waves. To identify the spindles the EEG data was divided into epochs from which appropriate features were extracted to differentiate spindles from the background EEG. The feature vectors used included the level of EOG activity, the quantity of significant peak-to-peak transitions, the wavelet packet energy (WPE) within the frequency band of interest (11–16 Hz) and the presence of K-complexes. EOG activity was tracked to identify NREM sleep sections. Spindles were marked as being present in those epochs in which the WPE and peak-to-peak activity were higher than predetermined thresholds. The thresholds were reduced on detection of K-complexes, mimicking manual scoring. The accuracy of the developed algorithm was verified by comparing to the manual scoring performed by a sleep specialist on the EEG data. The results from the algorithm look promising with a good degree of agreement with the manual scoring. When run on 3 hours of EEG data with 52 manually scored spindles the algorithm successfully detected 42 of them (80.7%) and of the total 21,600 epochs analyzed 290 were falsely detected as containing spindles. It was also observed that the true detection rate increases on varying the thresholds although this introduces further false detections.

Agreement of Two Different Laboratory Methods Used to Measure Electrolytes

Aim:The aim of our study was to do an agreement analysis of two different laboratory methods used to measure electrolytes i.e., between the ISE based Beckman Coulter Synchron CX9 PRO Biochemistry analyzer and RAL's Ion3 Flame Photometer (Técnica para el Laboratorio, Barcelona, Spain), in serum samples.Materials and Methods:This cross sectional study was done over a period of three months from September’09 through December’09 on routine biochemistry samples. A total of 6492 samples were received for routine biochemistry analysis from those 630 blood samples were randomly processed for this study. Two ml of sample was taken in a plain gel tube (LABTECH Disposables, Ahmedabad, India), centrifuged and further processed using both systems within one hour of the sampling to obtain the Na and K concentrations in the samples. The bias and variability of differences in measured values were analyzed according to Bland and Altman method.Results:Flame photometry method has drawbacks such as low throughput, requires manual operation, is a time consuming procedure. Ion selective electrodes technique is a more universal method for the high throughput determination of electrolytes in physiological samples; Beckman Coulter Synchron CX9 PRO is an example of such a system. The mean difference between the two methods (standard minus test) and 95% limits of agreement for sodium in serum was -7.8±17.3 (-42.2 to 26.6) and in urine was -22±41 (-104 to 60). Similarly, the mean difference between the two methods for potassium values in serum was found to be -0.25±0.75 (-1.75 to 1.25) and in urine was -5.3±38.9 (-83.1 to 72.5). With 95% confidence interval, the value of sodium and potassium as determined by both the methods lie between the upper and lower limit showing 95% limits of agreement.Conclusion:Good degree of agreement was seen on comparing the two methods for measuring the electrolytes; the use of Synchron CX9 in place of Flame photometer for electrolyte analysis in serum and urine is justified or use the two interchangeably.

Automatic 3D building extraction from aerial and space images for earthquake risk management

This paper contains two main parts. First, we give an overview of photogrammetric and remote sensing techniques in applications related to disaster management procedures. Remotely sensed data potentially provide valuable seismicity-related data in terms of both assessing the potential of risk and defining the state of vulnerability. The paper illustrates the use of advanced remote sensing technologies and methods for urban inventory and damage assessment. Second, we explain our proposed method for automatic damage assessment using multi view aerial images. We document the use of a novel methodology for assessing the damages of man-made objects. The problem is formulated in general, and for validation the approach is applied to a study area. This area is a part of the city of Bam, Iran that was hit by a strong earthquake on 26 December 2003. For our purpose digital surface models (DSMs) were created automatically from pre- and post-earthquake aerial images. We have explored the use of different kinds of extracted features, defined in both object and image spaces. This method utilises a methodology of applying Bayesian networks to a multi-view and multi-modal damaged objects description. By comparing pre- and post-earthquake data the amount of damage can be assessed. Based on visual inspection of the stereo images, three levels of damage (total collapse, partial collapse, no damage) were considered. The overall success rate – total number of correctly classified objects divided by the total number of samples – was found to be 80.7%. The results of the analysis show that a good degree of agreement has been reached between the assessment results and the reference data. The suggested approach is promising, but there is room for improvement.

Rapid detection of human Leishmania infantum infection: A comparative field study using the fast agglutination screening test and the direct agglutination test

This study aimed to evaluate the performance of a fast agglutination screening test (FAST) for serodiagnosis of human Leishmania infantum infection in Iran. FAST is based on the direct agglutination test (DAT) but combines with a higher parasite concentration and is performed with only one serum dilution. The validity of FAST for the detection of L. infantum infection in the field was compared with the direct agglutination test on 110 confirmed or patients suspected of infection with leishmaniasis, 177 healthy individuals and 41 patients with other infectious diseases who were from northwestern and southern parts of Iran. In this study, we found a 1:1600 cut-off point empirically by seeking the best correlation (90.8) between sera confirmed with visceral leishmaniasis and healthy control sera. A sensitivity of 95.4% (95% CI, 91.4-99.4) and specificity of 88.5% (95% CI, 84.2-92.8) were found with 1:1600 as a cut-off titer when DAT-confirmed cases were compared with the control groups. A good degree of agreement was found between FAST and DAT (90.8%) by Kappa analysis. FAST requires 2h for reading the results versus the 12-18h needed for DAT. As FAST is simple, rapid, sensitive and non-invasive and does not require a higher volume of antigens or much expertise, it can be used for screening and serodiagnosis of human L.infantum infection.

Validité de la somme angulaire comme technique d’extraction d’images planaires à partir de données tomoscintigraphiques pulmonaires de ventilation-perfusion

The aim of our study was to assess the concordance between the results of angular summed images obtained from lung SPECT data versus true planar images in the diagnosis of pulmonary embolism. One hundred and ten patients suspected of pulmonary embolism included in a prospective study underwent a planar lung scan and a lung SPECT. Planar images were extracted from SPECT data using an angular summing technique. Both modalities were reviewed according to revised Pioped criteria by two nuclear medicine physicians. Concordance between modalities and observers was compared with a weighted kappa test. A good degree of agreement between the two modalities (κ = 0.696) were found. Interobserver degree of agreement was similar in planar images (κ = 0.919) and in angular summed images (κ = 0.903). These results suggest that angular sum images from SPECT data are usable and concordant with ventilation perfusion planar images.

Rapid detection of Leishmania infantum infection in dogs: a comparative study using fast agglutination screening test (FAST) and direct agglutination test (DAT) in Iran

Canine visceral leishmaniasis (CVL) is not only a veterinary problem but has also a serious public health importance. Rapid detection of CVL is highly important for control of human visceral leishmaniasis in Iran. This study was aimed to compare the fast agglutination screening test (FAST) with direct agglutination test (DAT) as a standard serological test for the detection of anti-Leishmania antibodies on dog serum samples. DAT and FAST antigens were prepared in the School of Public Health, Tehran University of Medical Science. Altogether, 73 serum samples from Leishmania infantum infection dogs and 74 sera from healthy controls were collected from human VL/CVL endemic and non-endemic areas of Iran, respectively. All the sera were evaluated with both FAST and DAT techniques. A sensitivity of 98.60% (95% CI, 98.57-98.62) and specificity of 78.70% (95 CI%, 69.20-88.20) were found at a 1:160--(cut-off) titer when DAT confirmed cases were compared with healthy control. A good degree of agreement was observed between FAST and DAT (86.8%) by kappa analysis (p < 0.01). In conclusion, this study showed that FAST is very practical and simple diagnostic tool for the sero-diagnosis of CVL in endemic areas of Iran.

Coloraciones Ziehl-Neelsen y Safranina modificadas para el Diagnóstico de Cyclospora cayetanensis

Comparing modified Ziehl-Neelsen (ZNm) and modified Safranin (Sm) staining for detecting C. cayetanensis oocysts in stool samples. The sample to be analysed consisted of 100 stool samples which had been previously evaluated by direct microscopic examination and concentration. Each sample was then ZNm and Sm stained. Microscope examination was used as gold standard for comparing both techniques by statistical analysis. There was 95% sensitivity and 90% specificity for ZNm and 98% sensitivity and 100% specificity for Sm. The Kappa index was 0.93, signifying a very good degree of agreement between the two techniques. The use of either of the two stains for diagnosing C. cayetanensis can be recommended due to the high sensitivity and specificity for Zm and Sm found in this study and to the high degree of agreement between them.

A wind tunnel examination of shear stress partitioning for an assortment of surface roughness distributions

Surface roughness aids to ameliorate wind erosion by extracting a portion of the wind's momentum thereby reducing the quantity of stress on the surface. This paper evaluates the effect of different spatial arrangements of surface roughness on the partition of average drag forces and distribution of stress at the surface. A new tiered force balance was used in a wind tunnel to independently and simultaneously measure the drag on arrays of roughness elements and the drag on the intervening surface. In addition, Irwin sensors recorded point measurements of surface shear stress within the arrays. Roughness arrays consisted of small cylinders in four different spatial arrangements, one being staggered and three being simplifications of natural roughness configurations, at four roughness densities. Results from the tiered force balance and Irwin sensors indicate that the roughness configuration has a small impact on the average (R) and maximum (R″) drag partition. The protection of the surface increased with roughness density regardless of the roughness arrangement. Point measurements of shear stress revealed that the roughness configuration had a small impact on the distribution of shear stress at the surface, and that the maximum shear stress scaled to the average shear stress. Drag partition measurements were compared to the ratios predicted by the Raupach et al. (1993) model and a good degree of agreement was found for all configurations when using measured values of the β and m parameter.

Wave propagation in a generalized thermoelastic solid cylinder of arbitrary cross-section

In this article, the wave propagation in a generalized thermoelastic solid cylinder of arbitrary cross-section is discussed, using the Fourier expansion collocation method. The solid medium is assumed to be linear, isotropic, and dependent on the rate of temperature. Three displacement potential functions are introduced, to uncouple the equations of motion and the heat conduction. By imposing the continuity conditions the frequency equation corresponding to the problem is obtained using the Fourier expansion collocation method based on Suhubi’s generalized theory [Suhubi, E.S., 1975. Thermoelastic Solids. In: Eringen, A.C. (Ed.), Continuum Physics, vol. 2. Academic, New York, Chapter 2]. To compare the model with the existing literature, the results of a generalized thermoelastic solid cylinder are obtained and they are compared with the results of Erbay and Suhubi [Erbay, E.S., Suhubi, E.S., 1986. Longitudinal wavepropagationed thermoelastic cylinder. J. Thermal Stresses 9, 279–295]. It shows very good degree of agreement. The computed non-dimensional wavenumbers are presented in figures for various values of the material parameters. The general theory can be used to study any kind of cylinders with proper geometrical relations.

Eigenmode formations of m = 1 fast Alfvén waves in the ion-cyclotron frequency range in the GAMMA 10 central cell

The formation of eigenmodes with the m = 1 fast Alfvén waves in the ion-cyclotron range of frequency are investigated in the axisymmetric central cell of the GAMMA 10 tandem mirror. When the fast waves with frequencies near the fundamental ion-cyclotron frequency have been used for the plasma production, the saturation in the density has been observed. The spatial structure of the excited wave field is calculated in the central cell using a two-dimensional full wave code. The results of numerical analysis indicate that the increase in plasma density depends strongly on the eigenmode formations associated with the boundary conditions. The results of numerical analysis are compared with the results of measurements of the waves with magnetic probes. A very good degree of agreement is found between the theoretical results and the experimental results. It is suggested that the simultaneous excitation of several radial eigenmodes with high-harmonic fast waves is effective for higher density plasma production.

Effects of viscous dissipation on thermally developing forced convection in a porous saturated circular tube with an isoflux wall

The viscous dissipation effect on forced convection in a porous saturated circular tube with an isoflux wall is investigated on the basis of the Brinkman flow model. For the thermally developing region, a numerical study is reported while a perturbation analysis is presented to find expressions for the temperature profile and the Nusselt number for the fully developed region. The fully developed Nusselt number found by numerical solution for the developing region is compared with that of asymptotic analysis and a good degree of agreement is observed.