Gerds, Thomas A.
2016-01-01
Survival is difficult to estimate when observation periods of individuals differ in length. Students imagine sailing the Titanic and then recording whether they "live" or "die." A clever algorithm is performed which results in the Kaplan-Meier estimate of survival.
Survival analysis I: the Kaplan-Meier method
Stel, Vianda S.; Dekker, Friedo W.; Tripepi, Giovanni; Zoccali, Carmine; Jager, Kitty J.
2011-01-01
The Kaplan-Meier (KM) method is used to analyze 'time-to-event' data. The outcome in KM analysis often includes all-cause mortality, but could also include other outcomes such as the occurrence of a cardiovascular event. The purpose of this article is to explain the basic concepts of the KM method,
van Walraven, Carl; McAlister, Finlay A
2016-01-01
Risk estimates from Kaplan-Meier curves are well known to medical researchers, reviewers, and editors. In this study, we determined the proportion of Kaplan-Meier analyses published in prominent medical journals that are potentially biased because of competing events ("competing risk bias"). We randomly selected 100 studies that had at least one Kaplan-Meier analysis and were recently published in prominent medical journals. Susceptibility to competing risk bias was determined by examining the outcome and potential competing events. In susceptible studies, bias was quantified using a previously validated prediction model when the number of outcomes and competing events were given. Forty-six studies (46%) contained Kaplan-Meier analyses susceptible to competing risk bias. Sixteen studies (34.8%) susceptible to competing risk cited the number of outcomes and competing events; in six of these studies (6/16, 37.5%), the outcome risk from the Kaplan-Meier estimate (relative to the true risk) was biased upward by 10% or more. Almost half of Kaplan-Meier analyses published in medical journals are susceptible to competing risk bias and may overestimate event risk. This bias was found to be quantitatively important in a third of such studies. Copyright © 2016 Elsevier Inc. All rights reserved.
Kaplan-Meier Survival Analysis Overestimates the Risk of Revision Arthroplasty: A Meta-analysis.
Lacny, Sarah; Wilson, Todd; Clement, Fiona; Roberts, Derek J; Faris, Peter D; Ghali, William A; Marshall, Deborah A
2015-11-01
Although Kaplan-Meier survival analysis is commonly used to estimate the cumulative incidence of revision after joint arthroplasty, it theoretically overestimates the risk of revision in the presence of competing risks (such as death). Because the magnitude of overestimation is not well documented, the potential associated impact on clinical and policy decision-making remains unknown. We performed a meta-analysis to answer the following questions: (1) To what extent does the Kaplan-Meier method overestimate the cumulative incidence of revision after joint replacement compared with alternative competing-risks methods? (2) Is the extent of overestimation influenced by followup time or rate of competing risks? We searched Ovid MEDLINE, EMBASE, BIOSIS Previews, and Web of Science (1946, 1980, 1980, and 1899, respectively, to October 26, 2013) and included article bibliographies for studies comparing estimated cumulative incidence of revision after hip or knee arthroplasty obtained using both Kaplan-Meier and competing-risks methods. We excluded conference abstracts, unpublished studies, or studies using simulated data sets. Two reviewers independently extracted data and evaluated the quality of reporting of the included studies. Among 1160 abstracts identified, six studies were included in our meta-analysis. The principal reason for the steep attrition (1160 to six) was that the initial search was for studies in any clinical area that compared the cumulative incidence estimated using the Kaplan-Meier versus competing-risks methods for any event (not just the cumulative incidence of hip or knee revision); we did this to minimize the likelihood of missing any relevant studies. We calculated risk ratios (RRs) comparing the cumulative incidence estimated using the Kaplan-Meier method with the competing-risks method for each study and used DerSimonian and Laird random effects models to pool these RRs. Heterogeneity was explored using stratified meta-analyses and
Lacny, Sarah; Wilson, Todd; Clement, Fiona; Roberts, Derek J; Faris, Peter; Ghali, William A; Marshall, Deborah A
2018-01-01
Kaplan-Meier survival analysis overestimates cumulative incidence in competing risks (CRs) settings. The extent of overestimation (or its clinical significance) has been questioned, and CRs methods are infrequently used. This meta-analysis compares the Kaplan-Meier method to the cumulative incidence function (CIF), a CRs method. We searched MEDLINE, EMBASE, BIOSIS Previews, Web of Science (1992-2016), and article bibliographies for studies estimating cumulative incidence using the Kaplan-Meier method and CIF. For studies with sufficient data, we calculated pooled risk ratios (RRs) comparing Kaplan-Meier and CIF estimates using DerSimonian and Laird random effects models. We performed stratified meta-analyses by clinical area, rate of CRs (CRs/events of interest), and follow-up time. Of 2,192 identified abstracts, we included 77 studies in the systematic review and meta-analyzed 55. The pooled RR demonstrated the Kaplan-Meier estimate was 1.41 [95% confidence interval (CI): 1.36, 1.47] times higher than the CIF. Overestimation was highest among studies with high rates of CRs [RR = 2.36 (95% CI: 1.79, 3.12)], studies related to hepatology [RR = 2.60 (95% CI: 2.12, 3.19)], and obstetrics and gynecology [RR = 1.84 (95% CI: 1.52, 2.23)]. The Kaplan-Meier method overestimated the cumulative incidence across 10 clinical areas. Using CRs methods will ensure accurate results inform clinical and policy decisions. Copyright © 2017 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Grybaeck, P.; Naeslund, E.; Hellstroem, P.M.; Jacobsson, H.; Backman, L.
1996-01-01
It has been suggested that obesity is associated with an altered rate of gastric emptying, and that there are also sex differences in gastric emptying. The results of earlier studies examining gastric emptying rates in obesity and in males and females have proved inconsistent. The aim of this study was to investigate the influence of obesity and gender on gastric emptying, by extending conventional evaluation methods with Kaplan-Meier plots, in order to assess whether these factors have to be accounted for when interpreting results of scintigraphic gastric emptying tests. Twenty-one normal-weight volunteers and nine obese subjects were fed a standardised technetium-99m labelled albumin omelette. Imaging data were acquired at 5- and 10-min intervals in both posterior and anterior projections with the subjects in the sitting position. The half-emptying time, analysed by Kaplan-Meier plot (log-rank test), were shorter in obese subjects compared to normal-weight subjects and later in females compared to males. Also, the lag-phase and half-emptying time were shorter in obese females than in normal females. This study shows an association between different gastric emptying rates and obesity and gender. Therefore, body mass index and gender have to be accounted for when interpreting results of scintigraphic gastric emptying studies. (orig.). With 6 figs., 4 tabs
Energy Technology Data Exchange (ETDEWEB)
Grybaeck, P. [Department of Diagnostic Radiology, Karolinska Hospital, Stockholm (Sweden); Naeslund, E. [Department of Surgery, Karolinska Institute at Danderyd Hospital, Stockholm (Sweden); Hellstroem, P.M. [Department of Internal Medicine, Karolinska Hospital, Stockholm (Sweden); Jacobsson, H. [Department of Diagnostic Radiology, Karolinska Hospital, Stockholm (Sweden)]|[Department of Nuclear Medicine, Karolinska Hospital, Stockholm (Sweden); Backman, L. [Department of Surgery, Karolinska Institute at Danderyd Hospital, Stockholm (Sweden)
1996-12-01
It has been suggested that obesity is associated with an altered rate of gastric emptying, and that there are also sex differences in gastric emptying. The results of earlier studies examining gastric emptying rates in obesity and in males and females have proved inconsistent. The aim of this study was to investigate the influence of obesity and gender on gastric emptying, by extending conventional evaluation methods with Kaplan-Meier plots, in order to assess whether these factors have to be accounted for when interpreting results of scintigraphic gastric emptying tests. Twenty-one normal-weight volunteers and nine obese subjects were fed a standardised technetium-99m labelled albumin omelette. Imaging data were acquired at 5- and 10-min intervals in both posterior and anterior projections with the subjects in the sitting position. The half-emptying time, analysed by Kaplan-Meier plot (log-rank test), were shorter in obese subjects compared to normal-weight subjects and later in females compared to males. Also, the lag-phase and half-emptying time were shorter in obese females than in normal females. This study shows an association between different gastric emptying rates and obesity and gender. Therefore, body mass index and gender have to be accounted for when interpreting results of scintigraphic gastric emptying studies. (orig.). With 6 figs., 4 tabs.
Directory of Open Access Journals (Sweden)
Arnd Gross
Full Text Available BACKGROUND: Analysis of clinical studies often necessitates multiple graphical representations of the results. Many professional software packages are available for this purpose. Most packages are either only commercially available or hard to use especially if one aims to generate or customize a huge number of similar graphical outputs. We developed a new, freely available software tool called KMWin (Kaplan-Meier for Windows facilitating Kaplan-Meier survival time analysis. KMWin is based on the statistical software environment R and provides an easy to use graphical interface. Survival time data can be supplied as SPSS (sav, SAS export (xpt or text file (dat, which is also a common export format of other applications such as Excel. Figures can directly be exported in any graphical file format supported by R. RESULTS: On the basis of a working example, we demonstrate how to use KMWin and present its main functions. We show how to control the interface, customize the graphical output, and analyse survival time data. A number of comparisons are performed between KMWin and SPSS regarding graphical output, statistical output, data management and development. Although the general functionality of SPSS is larger, KMWin comprises a number of features useful for survival time analysis in clinical trials and other applications. These are for example number of cases and number of cases under risk within the figure or provision of a queue system for repetitive analyses of updated data sets. Moreover, major adjustments of graphical settings can be performed easily on a single window. CONCLUSIONS: We conclude that our tool is well suited and convenient for repetitive analyses of survival time data. It can be used by non-statisticians and provides often used functions as well as functions which are not supplied by standard software packages. The software is routinely applied in several clinical study groups.
Mbengue, Mouhamed Abdou Salam; Mboup, Aminata; Ly, Indou Deme; Faye, Adama; Camara, Fatou Bintou Niang; Thiam, Moussa; Ndiaye, Birahim Pierre; Dieye, Tandakha Ndiaye; Mboup, Souleymane
2017-01-01
Expanded programme on immunizations in resource-limited settings currently measure vaccination coverage defined as the proportion of children aged 12-23 months that have completed their vaccination. However, this indicator does not address the important question of when the scheduled vaccines were administered. We assessed the determinants of timely immunization to help the national EPI program manage vaccine-preventable diseases and impact positively on child survival in Senegal. Vaccination data were obtained from the Demographic and Health Survey (DHS) carried out across the 14 regions in the country. Children were aged between 12-23 months. The assessment of vaccination coverage was done with the health card and/or by the mother's recall of the vaccination act. For each vaccine, an assessment of delay in age-appropriate vaccination was done following WHO recommendations. Additionally, Kaplan-Meier survival function was used to estimate the proportion vaccinated by age and cox-proportional hazards models were used to examine risk factors for delays. A total of 2444 living children between 12-23 months of age were included in the analysis. The country vaccination was below the WHO recommended coverage level and, there was a gap in timeliness of children immunization. While BCG vaccine uptake was over 95%, coverage decreased with increasing number of Pentavalent vaccine doses (Penta 1: 95.6%, Penta 2: 93.5%: Penta 3: 89.2%). Median delay for BCG was 1.7 weeks. For polio at birth, the median delay was 5 days; all other vaccine doses had median delays of 2-4 weeks. For Penta 1 and Penta 3, 23.5% and 15.7% were given late respectively. A quarter of measles vaccines were not administered or were scheduled after the recommended age. Vaccinations that were not administered within the recommended age ranges were associated with mothers' poor education level, multiple siblings, low socio-economic status and living in rural areas. A significant delay in receipt of infant
Mbengue, Mouhamed Abdou Salam; Mboup, Aminata; Ly, Indou Deme; Faye, Adama; Camara, Fatou Bintou Niang; Thiam, Moussa; Ndiaye, Birahim Pierre; Dieye, Tandakha Ndiaye; Mboup, Souleymane
2017-01-01
Introduction Expanded programme on immunizations in resource-limited settings currently measure vaccination coverage defined as the proportion of children aged 12-23 months that have completed their vaccination. However, this indicator does not address the important question of when the scheduled vaccines were administered. We assessed the determinants of timely immunization to help the national EPI program manage vaccine-preventable diseases and impact positively on child survival in Senegal. Methods Vaccination data were obtained from the Demographic and Health Survey (DHS) carried out across the 14 regions in the country. Children were aged between 12-23 months. The assessment of vaccination coverage was done with the health card and/or by the mother’s recall of the vaccination act. For each vaccine, an assessment of delay in age-appropriate vaccination was done following WHO recommendations. Additionally, Kaplan-Meier survival function was used to estimate the proportion vaccinated by age and cox-proportional hazards models were used to examine risk factors for delays. Results A total of 2444 living children between 12–23 months of age were included in the analysis. The country vaccination was below the WHO recommended coverage level and, there was a gap in timeliness of children immunization. While BCG vaccine uptake was over 95%, coverage decreased with increasing number of Pentavalent vaccine doses (Penta 1: 95.6%, Penta 2: 93.5%: Penta 3: 89.2%). Median delay for BCG was 1.7 weeks. For polio at birth, the median delay was 5 days; all other vaccine doses had median delays of 2-4 weeks. For Penta 1 and Penta 3, 23.5% and 15.7% were given late respectively. A quarter of measles vaccines were not administered or were scheduled after the recommended age. Vaccinations that were not administered within the recommended age ranges were associated with mothers’ poor education level, multiple siblings, low socio-economic status and living in rural areas
Caetano, S L; Rosa, G J M; Savegnago, R P; Ramos, S B; Bezerra, L A F; Lôbo, R B; de Paz, C C P; Munari, D P
2013-04-01
In most studies on beef cattle longevity, only the cows reaching a given number of calvings by a specific age are considered in the analyses. With the aim of evaluating all cows with productive life in herds, taking into consideration the different forms of management on each farm, it was proposed to measure cow longevity from age at last calving (ALC), that is, the most recent calving registered in the files. The objective was to characterize this trait in order to study the longevity of Nellore cattle, using the Kaplan-Meier estimators and the Cox model. The covariables and class effects considered in the models were age at first calving (AFC), year and season of birth of the cow and farm. The variable studied (ALC) was classified as presenting complete information (uncensored = 1) or incomplete information (censored = 0), using the criterion of the difference between the date of each cow's last calving and the date of the latest calving at each farm. If this difference was >36 months, the cow was considered to have failed. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The records of 11 791 animals from 22 farms within the Nellore Breed Genetic Improvement Program ('Nellore Brazil') were used. In the estimation process using the Kaplan-Meier model, the variable of AFC was classified into three age groups. In individual analyses, the log-rank test and the Wilcoxon test in the Kaplan-Meier model showed that all covariables and class effects had significant effects (P 0.05). This analysis indicated that each month added to AFC diminished the risk of the cow's failure in the herd by 2%. Nonetheless, this does not imply that animals with younger AFC had less profitability. Cows with greater numbers of calvings were more precocious than those with fewer calvings.
DEFF Research Database (Denmark)
Gerds, Thomas Alexander
2016-01-01
they are observed by a neighbouring student while they try to hold their breath as long as they can. The observation periods are designed such that some students ‘drown’ and other ‘survive’ until the end of the experiment. Based on the data collected, it is explained why even simple statistics may fail when applied...
Directory of Open Access Journals (Sweden)
R. A. Armstrong
2014-01-01
Full Text Available Factors associated with duration of dementia in a consecutive series of 103 Alzheimer’s disease (AD cases were studied using the Kaplan-Meier estimator and Cox regression analysis (proportional hazard model. Mean disease duration was 7.1 years (range: 6 weeks–30 years, standard deviation = 5.18; 25% of cases died within four years, 50% within 6.9 years, and 75% within 10 years. Familial AD cases (FAD had a longer duration than sporadic cases (SAD, especially cases linked to presenilin (PSEN genes. No significant differences in duration were associated with age, sex, or apolipoprotein E (Apo E genotype. Duration was reduced in cases with arterial hypertension. Cox regression analysis suggested longer duration was associated with an earlier disease onset and increased senile plaque (SP and neurofibrillary tangle (NFT pathology in the orbital gyrus (OrG, CA1 sector of the hippocampus, and nucleus basalis of Meynert (NBM. The data suggest shorter disease duration in SAD and in cases with hypertensive comorbidity. In addition, degree of neuropathology did not influence survival, but spread of SP/NFT pathology into the frontal lobe, hippocampus, and basal forebrain was associated with longer disease duration.
Applying Kaplan-Meier to Item Response Data
McNeish, Daniel
2018-01-01
Some IRT models can be equivalently modeled in alternative frameworks such as logistic regression. Logistic regression can also model time-to-event data, which concerns the probability of an event occurring over time. Using the relation between time-to-event models and logistic regression and the relation between logistic regression and IRT, this…
Kaplan-Meier type distributions for linear contact distributions
Hansen, M.B.; Gill, R.D.; Baddeley, A.
1996-01-01
The linear contact distribution function is shown to be continuously dierentiable for any stationary random closed set which implies the existence of a continuous density and hazard rate Moreover it is proved that the density is monotone decreasing When the linear contact distribution function is
Hosseini, Seyed Farhad; Hashemian, Ali; Moetakef-Imani, Behnam; Hadidimoud, Saied
2018-03-01
In the present paper, the isogeometric analysis (IGA) of free-form planar curved beams is formulated based on the nonlinear Timoshenko beam theory to investigate the large deformation of beams with variable curvature. Based on the isoparametric concept, the shape functions of the field variables (displacement and rotation) in a finite element analysis are considered to be the same as the non-uniform rational basis spline (NURBS) basis functions defining the geometry. The validity of the presented formulation is tested in five case studies covering a wide range of engineering curved structures including from straight and constant curvature to variable curvature beams. The nonlinear deformation results obtained by the presented method are compared to well-established benchmark examples and also compared to the results of linear and nonlinear finite element analyses. As the nonlinear load-deflection behavior of Timoshenko beams is the main topic of this article, the results strongly show the applicability of the IGA method to the large deformation analysis of free-form curved beams. Finally, it is interesting to notice that, until very recently, the large deformations analysis of free-form Timoshenko curved beams has not been considered in IGA by researchers.
Abbasi, Jassem; Sarafrazi, Shiva; Riazi, Masoud; Ghaedi, Mojtaba
2018-02-01
Spontaneous imbibition is the main oil production mechanism in the water invaded zone of a naturally fractured reservoir (NFR). Different scaling equations have been presented in the literature for upscaling of core scale imbibition recovery curves to field scale matrix blocks. Various scale dependent parameters such as gravity effects and boundary influences are required to be considered in the upscaling process. Fluid flow from matrix blocks to the fracture system is highly dependent on the permeability value in the horizontal and vertical directions. The purpose of this study is to include permeability anisotropy in the available scaling equations to improve the prediction of imbibition assisted oil production in NFRs. In this paper, a commercial reservoir simulator was used to obtain imbibition recovery curves for different scenarios. Then, the effect of permeability anisotropy on imbibition recovery curves was investigated, and the weakness of the existing scaling equations for anisotropic rocks was demonstrated. Consequently, an analytical shape factor was introduced that can better scale all the curves related to anisotropic matrix blocks.
A curved multi-component aerosol hygroscopicity model framework: 2 Including organics
Topping, D. O.; McFiggans, G. B.; Coe, H.
2004-12-01
This paper describes the inclusion of organic particulate material within the Aerosol Diameter Dependent Equilibrium Model (ADDEM) framework described in the companion paper applied to inorganic aerosol components. The performance of ADDEM is analysed in terms of its capability to reproduce the behaviour of various organic and mixed inorganic/organic systems using recently published bulk data. Within the modelling architecture already described two separate thermodynamic models are coupled in an additive approach and combined with a method for solving the Köhler equation in order to develop a tool for predicting the water content associated with an aerosol of known inorganic/organic composition and dry size. For development of the organic module, the widely used group contribution method UNIFAC is employed to explicitly deal with the non-ideality in solution. The UNIFAC predictions for components of atmospheric importance were improved considerably by using revised interaction parameters derived from electro-dynamic balance studies. Using such parameters, the model was found to adequately describe mixed systems including 5-6 dicarboxylic acids, down to low relative humidity conditions. The additive approach for modelling mixed inorganic/organic systems worked well for a variety of mixtures. As expected, deviations between predicted and measured data increase with increasing concentration. Available surface tension models, used in evaluating the Kelvin term, were found to reproduce measured data with varying success. Deviations from experimental data increased with increased organic compound complexity. For components only slightly soluble in water, significant deviations from measured surface tension depression behaviour were predicted with both model formalisms tested. A Sensitivity analysis showed that such variation is likely to lead to predicted growth factors within the measurement uncertainty for growth factor taken in the sub-saturated regime. Greater
Directory of Open Access Journals (Sweden)
D. O. Topping
2005-01-01
Full Text Available This paper describes the inclusion of organic particulate material within the Aerosol Diameter Dependent Equilibrium Model (ADDEM framework described in the companion paper applied to inorganic aerosol components. The performance of ADDEM is analysed in terms of its capability to reproduce the behaviour of various organic and mixed inorganic/organic systems using recently published bulk data. Within the modelling architecture already described two separate thermodynamic models are coupled in an additive approach and combined with a method for solving the Kohler equation in order to develop a tool for predicting the water content associated with an aerosol of known inorganic/organic composition and dry size. For development of the organic module, the widely used group contribution method UNIFAC is employed to explicitly deal with the non-ideality in solution. The UNIFAC predictions for components of atmospheric importance were improved considerably by using revised interaction parameters derived from electro-dynamic balance studies. Using such parameters, the model was found to adequately describe mixed systems including 5–6 dicarboxylic acids, down to low relative humidity conditions. By comparison with electrodynamic balance data, it was also found that the model was capable of capturing the behaviour of aqueous aerosols containing Suwannee River Fulvic acid, a structure previously used to represent the functionality of complex oxidised macromolecules often found in atmospheric aerosols. The additive approach for modelling mixed inorganic/organic systems worked well for a variety of mixtures. As expected, deviations between model predictions and measurements increase with increasing concentration. Available surface tension models, used in evaluating the Kelvin term, were found to reproduce measured data with varying success. Deviations from experimental data increased with increased organic compound complexity. For components only slightly
A curved multi-component aerosol hygroscopicity model framework: Part 2 Including organic compounds
Topping, D. O.; McFiggans, G. B.; Coe, H.
2005-05-01
This paper describes the inclusion of organic particulate material within the Aerosol Diameter Dependent Equilibrium Model (ADDEM) framework described in the companion paper applied to inorganic aerosol components. The performance of ADDEM is analysed in terms of its capability to reproduce the behaviour of various organic and mixed inorganic/organic systems using recently published bulk data. Within the modelling architecture already described two separate thermodynamic models are coupled in an additive approach and combined with a method for solving the Kohler equation in order to develop a tool for predicting the water content associated with an aerosol of known inorganic/organic composition and dry size. For development of the organic module, the widely used group contribution method UNIFAC is employed to explicitly deal with the non-ideality in solution. The UNIFAC predictions for components of atmospheric importance were improved considerably by using revised interaction parameters derived from electro-dynamic balance studies. Using such parameters, the model was found to adequately describe mixed systems including 5-6 dicarboxylic acids, down to low relative humidity conditions. By comparison with electrodynamic balance data, it was also found that the model was capable of capturing the behaviour of aqueous aerosols containing Suwannee River Fulvic acid, a structure previously used to represent the functionality of complex oxidised macromolecules often found in atmospheric aerosols. The additive approach for modelling mixed inorganic/organic systems worked well for a variety of mixtures. As expected, deviations between model predictions and measurements increase with increasing concentration. Available surface tension models, used in evaluating the Kelvin term, were found to reproduce measured data with varying success. Deviations from experimental data increased with increased organic compound complexity. For components only slightly soluble in water
Engelen, Carolin; Moritz, Andreas; Barthel, Franziska; Bauer, Natali
2017-11-29
Thrombelastography is a useful tool in assessment of hemostasis. Beside the traditional variables, the velocity curve and the variable delta have lately earned attention. The velocity curve provides knowledge about the speed of clot formation including information about thrombin generation. Delta, which only reflects enzymatic coagulation, allows the determination of the origin of hypercoagulability when compared to clot rigidity, a variable that reflects both platelet and enzymatic activity. The aim was to establish preliminary reference intervals for feline thrombelastography including the velocity curve variables and delta obtained after 60 min of storage including the assessment of coefficients of variation. Furthermore, the effect of citrate storage time (30 versus 60 min) on feline thrombelastography will be determined. Prolonged storage times significantly reduced reaction (R) (P = 0.019) and clotting (K) (P = 0.008) times, split point (SP) (P = 0.019) and time to maximum rate of thrombus generation (TMRTG) (P = 0.023) values whereas maximum rate of thrombus generation (MRTG) significantly increased (P = 0.040). Preliminary reference intervals: R (min): 2.7-18.1; K (min): 0.8-3.9; alpha (°): 27.6-75.2; maximum amplitude (mm): 18.5-62.5; clot rigidity (dyn/cm 2 ): 1.2-8.2; coagulation index: -4.6 - 2.6; SP (min): 2.4-15.4; delta (min): 0.3-3.1; thrombus generation (mm/min): 255.3-751.2; MRTG (mm/min): 4.0-19.3; TMRTG (min): 3.5-22.0; maximum rate of lysis (mm/min): 0.0-4.7 and time to maximum rate of lysis (min): 0.4-55.8. Storage for 60 versus 30 min induces hypercoagulable tracings including the velocity curve, some of which variables (MRTG, TMRTG) might function as sensitive markers for changes in the coagulation activity. Because of the impact of citrate storage time on thrombelastography, reference intervals have to be established using a specific and constant storage time in each laboratory.
Lee, Young-Kyun; Park, Chan Ho; Ha, Yong-Chan; Kim, Do-Yeon; Lyu, Sung-Hwa; Koo, Kyung-Hoi
2017-06-01
Various osteotomies have been introduced to treat osteonecrosis of the femoral head. The purpose of this study was to compare surgical parameters, postoperative limb length discrepancy, and minimum 5-year clinical and radiological results between transtrochanteric curved varus osteotomy (TCVO) and transtrochanteric rotational osteotomy (TRO) for osteonecrosis of the femoral head. From 2004 to 2009, 103 consecutive TROs (97 patients) followed by 72 consecutive TCVOs (64 patients) were performed for the treatment of osteonecrosis of the femoral head. Of these, 85 patients (91 hips) in the TRO group and 58 patients (65 hips) in the TCVO group completed minimum 5-year clinical and radiological follow-up. The Kaplan-Meier product-limit method was used to estimate survival. The TCVO group had shorter operation time ( p < 0.05) and less estimated blood loss ( p = 0.026). Postoperative collapse developed in 26 hips (28.6%) in the TRO group and 7 hips (10.8%) in the TCVO group ( p = 0.007). Osteophyte formation was observed in 34 hips (37.4%) in the TRO group and 13 hips (20%) in the TCVO group ( p = 0.020). Fifteen hips (16.5%) in the TRO group and 7 hips (10.8%) in the TCVO group underwent conversion total hip arthroplasty (THA). The survival rate at 9 years with radiographic collapse as the endpoint was 68.7% (95% confidence interval [CI], 58.1% to 79.3%) in the TRO group, and 84.7% (95% CI, 71.5% to 97.9%) in the TCVO group. With conversion to THA as the endpoint, the survival rate was 82.2% (95% CI, 73.1% to 91.3%) in the TRO group and 89.2% (95% CI, 81.7% to 96.7%) in the TCVO group. The comparison indicates that TCVO was better than TRO in terms of surgical parameters including operation time and estimated blood loss while the 9-year survival rates were similar.
Directory of Open Access Journals (Sweden)
Ahmet Mete Vural
2017-09-01
Full Text Available Power flow study in a power network embedded with FACTS device requires effort in program coding. Moreover, Newton-Raphson method should be modified by embedding injected power components into the algorithm. In this study, we have proposed a method for modeling of one of the newest FACTS concepts in power flow study without program coding or modification of existing Newton-Raphson algorithm. Real and reactive power injections for each voltage source converter of Back-to-Back Static Synchronous Compensator (BtB-STATCOM are PI regulated to their desired steady-state values. With this respect, reactive power injection of each voltage source converter as well as real power transfer among them can be assigned as control constraint. Operating losses are also taken into account in the proposed modeling approach. Furthermore, proposed model can be easily modified for the modeling of conventional STATCOM having only one voltage source converter or two STATCOMs operating independently. The proposed modeling approach is verified in PSCAD through a number of simulation scenarios in BtB-STATCOM and STATCOM embedded power systems, namely 1-Machine 4-Bus system and 3-Machine 7-Bus system. PV curves of local buses compensated by BtB-STATCOM and STATCOM are presented and compared. Steady-state performance of BtB-STATCOM and STATCOM is also compared in power flow handling.
Maier, Michael W; Streit, Marcus R; Innmann, Moritz M; Krüger, Marlis; Nadorf, Jan; Kretzer, J Philippe; Ewerbeck, Volker; Gotterbarm, Tobias
2015-12-01
Short stems have become more and more popular for cementless total hip arthroplasty in the past few years. While conventional, uncemented straight stems for primary total hip arthroplasty (THA) have shown high survival rates in the long term, it is not known whether uncemented short stems represent a reasonable alternative. As cortical hypertrophy has been reported for short stems, the aim of this study was to determine the radiographic prevalence of cortical hypertrophy and to assess the clinical outcome of a frequently used short, curved hip stem. We retrospectively studied the clinical and radiographic results of our first 100 consecutive THAs (97 patients) using the Fitmore® hip stem. Mean age at the time of index arthroplasty was 59 years (range, 19 - 79 years). Clinical outcome and radiographic results were assessed with a minimum follow-up of 2 years, and Kaplan-Meier survivorship analysis was used to estimate survival for different endpoints. After a mean follow-up of 3.3 years (range, 2.0 - 4.4 years), two patients (two hips) had died, and three patients (four hips) were lost to follow-up. Kaplan-Meier analysis estimated a survival rate of 100 % at 3.8 years, with revision for any reason as the endpoint. No femoral component showed radiographic signs of loosening. No osteolysis was detected. Cortical hypertrophy was found in 50 hips (63 %), predominantly in Gruen zone 3 and 5. In the cortical hypertrophy group, two patients (two hips; 4 %) reported some thigh pain in combination with pain over the greater trochanter region during physical exercise (UCLA Score 6 and 7). There was no significant difference concerning the clinical outcome between the cortical hypertrophy and no cortical hypertrophy group. The survival rate and both clinical and the radiographic outcome confirm the encouraging results for short, curved uncemented stems. Postoperative radiographs frequently displayed cortical hypertrophy but it had no significant effect on the
African Journals Online (AJOL)
s m m '. o o o g. Pcrcunt Iurvlvlng. N o. Follow-up (months). Fig. 3: Kaplan-Meier curve showing progression-free sur- vival of the whole series. TURBT before inclusion into the study and the development of recurrence or muscle-invasive progression. Kaplan-Meier survival curves were used to estimate recurrence-free and ...
Benìtez-Ponce, P.C.
2003-01-01
After the inclusion of carbon sinks in the Kyoto Protocol, greenhouse gas mitigation policies should account for abatement measurements in both the energy and forestry sectors. This report deals with the development of a methodology for estimating cost-curves of carbon sequestration with
Directory of Open Access Journals (Sweden)
Mahdis Bagherian
2015-03-01
Full Text Available Introduction: Root canal instrumentation is an important phase in root canal therapy. Since success in endodontic treatment depends on file defect and fracture, the aim of this study was to compare the evaluation of defect and fracture in rotary and reciproc files in severe curved root canals. Materials & Methods: In this experimental study, 60 mesial canals of human closed apex molars with more than 30° canal curvature were randomly divided into two groups. In first group M-two rotary files number# 15, 20, and 25 and in second group R25 reciproc file were used for filing, respectively. A ×8 magnifier was applied to evaluate the defect or fracture presence in each side and if it were observed, a new file would be replaced. Therefore, the number of prepared canals with each file and fractured or defective files and the place of fracture in root canal were recorded. Kaplan Meier curve and log rank test were done by using SPSS v.22. Results: In rotary group, seven and two files were fractured and defected, respectively and four files were fractured and no defect was observed in reciproc group. Although the mean of the number of prepared canals until fracture or defect in rotary and reciproc groups was 3.3 and 7.06, respectively, there were no significant differences between two systems. All file’s fractures occurred in apical regions . Conclusion: The results showed that there was no significant difference in defects or fractures of rotary and reciproc systems. Reciproc instruments can be more effective than rotary ones because the root canal preparation in rotary instruments is longer than in reciproc system.
Utilization of ICU Data to Improve 30 and 60 Day HENRE Mortality Models, Revision 1
2017-05-12
gender and available medical treatment (Stricklin, 2016). However, when burn is included, this model does not consider individual demographic...indicating that the NLR only weakly discriminates between surviving and non-surviving patients in this study. Kaplan-Meier curves of patients grouped by...for demographics (age and gender ) in the context of 60-day radiation-induced mortality. In the future, we would like to account for demographics in the
Sakurai-Yageta, Mika; Maruyama, Tomoko; Suzuki, Takashi; Ichikawa, Kazuhisa; Murakami, Yoshinori
2015-01-01
Protein components of cell adhesion machinery show continuous renewal even in the static state of epithelial cells and participate in the formation and maintenance of normal epithelial architecture and tumor suppression. CADM1 is a tumor suppressor belonging to the immunoglobulin superfamily of cell adhesion molecule and forms a cell adhesion complex with an actin-binding protein, 4.1B, and a scaffold protein, MPP3, in the cytoplasm. Here, we investigate dynamic regulation of the CADM1-4.1B-MPP3 complex in mature cell adhesion by fluorescence recovery after photobleaching (FRAP) analysis. Traditional FRAP analysis were performed for relatively short period of around 10min. Here, thanks to recent advances in the sensitive laser detector systems, we examine FRAP of CADM1 complex for longer period of 60 min and analyze the recovery with exponential curve-fitting to distinguish the fractions with different diffusion constants. This approach reveals that the fluorescence recovery of CADM1 is fitted to a single exponential function with a time constant (τ) of approximately 16 min, whereas 4.1B and MPP3 are fitted to a double exponential function with two τs of approximately 40-60 sec and 16 min. The longer τ is similar to that of CADM1, suggesting that 4.1B and MPP3 have two distinct fractions, one forming a complex with CADM1 and the other present as a free pool. Fluorescence loss in photobleaching analysis supports the presence of a free pool of these proteins near the plasma membrane. Furthermore, double exponential fitting makes it possible to estimate the ratio of 4.1B and MPP3 present as a free pool and as a complex with CADM1 as approximately 3:2 and 3:1, respectively. Our analyses reveal a central role of CADM1 in stabilizing the complex with 4.1B and MPP3 and provide insight in the dynamics of adhesion complex formation. PMID:25780926
Sakurai-Yageta, Mika; Maruyama, Tomoko; Suzuki, Takashi; Ichikawa, Kazuhisa; Murakami, Yoshinori
2015-01-01
Protein components of cell adhesion machinery show continuous renewal even in the static state of epithelial cells and participate in the formation and maintenance of normal epithelial architecture and tumor suppression. CADM1 is a tumor suppressor belonging to the immunoglobulin superfamily of cell adhesion molecule and forms a cell adhesion complex with an actin-binding protein, 4.1B, and a scaffold protein, MPP3, in the cytoplasm. Here, we investigate dynamic regulation of the CADM1-4.1B-MPP3 complex in mature cell adhesion by fluorescence recovery after photobleaching (FRAP) analysis. Traditional FRAP analysis were performed for relatively short period of around 10 min. Here, thanks to recent advances in the sensitive laser detector systems, we examine FRAP of CADM1 complex for longer period of 60 min and analyze the recovery with exponential curve-fitting to distinguish the fractions with different diffusion constants. This approach reveals that the fluorescence recovery of CADM1 is fitted to a single exponential function with a time constant (τ) of approximately 16 min, whereas 4.1B and MPP3 are fitted to a double exponential function with two τs of approximately 40-60 sec and 16 min. The longer τ is similar to that of CADM1, suggesting that 4.1B and MPP3 have two distinct fractions, one forming a complex with CADM1 and the other present as a free pool. Fluorescence loss in photobleaching analysis supports the presence of a free pool of these proteins near the plasma membrane. Furthermore, double exponential fitting makes it possible to estimate the ratio of 4.1B and MPP3 present as a free pool and as a complex with CADM1 as approximately 3:2 and 3:1, respectively. Our analyses reveal a central role of CADM1 in stabilizing the complex with 4.1B and MPP3 and provide insight in the dynamics of adhesion complex formation.
Stewart, David J.; Behrens, Carmen; Roth, Jack; Wistuba, Ignacio I.
2010-01-01
Background For processes that follow first order kinetics, exponential decay nonlinear regression analysis (EDNRA) may delineate curve characteristics and suggest processes affecting curve shape. We conducted a preliminary feasibility assessment of EDNRA of patient survival curves. Methods EDNRA was performed on Kaplan-Meier overall survival (OS) and time-to-relapse (TTR) curves for 323 patients with resected NSCLC and on OS and progression-free survival (PFS) curves from selected publications. Results and Conclusions In our resected patients, TTR curves were triphasic with a “cured” fraction of 60.7% (half-life [t1/2] >100,000 months), a rapidly-relapsing group (7.4%, t1/2=5.9 months) and a slowly-relapsing group (31.9%, t1/2=23.6 months). OS was uniphasic (t1/2=74.3 months), suggesting an impact of co-morbidities; hence, tumor molecular characteristics would more likely predict TTR than OS. Of 172 published curves analyzed, 72 (42%) were uniphasic, 92 (53%) were biphasic, 8 (5%) were triphasic. With first-line chemotherapy in advanced NSCLC, 87.5% of curves from 2-3 drug regimens were uniphasic vs only 20% of those with best supportive care or 1 drug (p<0.001). 54% of curves from 2-3 drug regimens had convex rapid-decay phases vs 0% with fewer agents (p<0.001). Curve convexities suggest that discontinuing chemotherapy after 3-6 cycles “synchronizes” patient progression and death. With postoperative adjuvant chemotherapy, the PFS rapid-decay phase accounted for a smaller proportion of the population than in controls (p=0.02) with no significant difference in rapid-decay t1/2, suggesting adjuvant chemotherapy may move a subpopulation of patients with sensitive tumors from the relapsing group to the cured group, with minimal impact on time to relapse for a larger group of patients with resistant tumors. In untreated patients, the proportion of patients in the rapid-decay phase increased (p=0.04) while rapid-decay t1/2 decreased (p=0.0004) with increasing
Simulating Supernova Light Curves
Energy Technology Data Exchange (ETDEWEB)
Even, Wesley Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dolence, Joshua C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-05-05
This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.
Whiley, David M; Jacob, Kevin; Nakos, Jennifer; Bletchly, Cheryl; Nimmo, Graeme R; Nissen, Michael D; Sloots, Theo P
2012-06-01
Numerous real-time PCR assays have been described for detection of the influenza A H275Y alteration. However, the performance of these methods can be undermined by sequence variation in the regions flanking the codon of interest. This is a problem encountered more broadly in microbial diagnostics. In this study, we developed a modification of hybridization probe-based melting curve analysis, whereby primers are used to mask proximal mutations in the sequence targets of hybridization probes, so as to limit the potential for sequence variation to interfere with typing. The approach was applied to the H275Y alteration of the influenza A (H1N1) 2009 strain, as well as a Neisseria gonorrhoeae mutation associated with antimicrobial resistance. Assay performances were assessed using influenza A and N. gonorrhoeae strains characterized by DNA sequencing. The modified hybridization probe-based approach proved successful in limiting the effects of proximal mutations, with the results of melting curve analyses being 100% consistent with the results of DNA sequencing for all influenza A and N. gonorrhoeae strains tested. Notably, these included influenza A and N. gonorrhoeae strains exhibiting additional mutations in hybridization probe targets. Of particular interest was that the H275Y assay correctly typed influenza A strains harbouring a T822C nucleotide substitution, previously shown to interfere with H275Y typing methods. Overall our modified hybridization probe-based approach provides a simple means of circumventing problems caused by sequence variation, and offers improved detection of the influenza A H275Y alteration and potentially other resistance mechanisms.
International Nuclear Information System (INIS)
Pickles, W.L.; McClure, J.W.; Howell, R.H.
1978-05-01
A sophisticated nonlinear multiparameter fitting program was used to produce a best fit calibration curve for the response of an x-ray fluorescence analyzer to uranium nitrate, freeze dried, 0.2% accurate, gravimetric standards. The program is based on unconstrained minimization subroutine, VA02A. The program considers the mass values of the gravimetric standards as parameters to be fit along with the normal calibration curve parameters. The fitting procedure weights with the system errors and the mass errors in a consistent way. The resulting best fit calibration curve parameters reflect the fact that the masses of the standard samples are measured quantities with a known error. Error estimates for the calibration curve parameters can be obtained from the curvature of the ''Chi-Squared Matrix'' or from error relaxation techniques. It was shown that nondispersive XRFA of 0.1 to 1 mg freeze-dried UNO 3 can have an accuracy of 0.2% in 1000 s
Titration Curves: Fact and Fiction.
Chamberlain, John
1997-01-01
Discusses ways in which datalogging equipment can enable titration curves to be measured accurately and how computing power can be used to predict the shape of curves. Highlights include sources of error, use of spreadsheets to generate titration curves, titration of a weak acid with a strong alkali, dibasic acids, weak acid and weak base, and…
Algebraic curves and cryptography
Murty, V Kumar
2010-01-01
It is by now a well-known paradigm that public-key cryptosystems can be built using finite Abelian groups and that algebraic geometry provides a supply of such groups through Abelian varieties over finite fields. Of special interest are the Abelian varieties that are Jacobians of algebraic curves. All of the articles in this volume are centered on the theme of point counting and explicit arithmetic on the Jacobians of curves over finite fields. The topics covered include Schoof's \\ell-adic point counting algorithm, the p-adic algorithms of Kedlaya and Denef-Vercauteren, explicit arithmetic on
Lagrangian Curves on Spectral Curves of Monopoles
International Nuclear Information System (INIS)
Guilfoyle, Brendan; Khalid, Madeeha; Ramon Mari, Jose J.
2010-01-01
We study Lagrangian points on smooth holomorphic curves in TP 1 equipped with a natural neutral Kaehler structure, and prove that they must form real curves. By virtue of the identification of TP 1 with the space LE 3 of oriented affine lines in Euclidean 3-space, these Lagrangian curves give rise to ruled surfaces in E 3 , which we prove have zero Gauss curvature. Each ruled surface is shown to be the tangent lines to a curve in E 3 , called the edge of regression of the ruled surface. We give an alternative characterization of these curves as the points in E 3 where the number of oriented lines in the complex curve Σ that pass through the point is less than the degree of Σ. We then apply these results to the spectral curves of certain monopoles and construct the ruled surfaces and edges of regression generated by the Lagrangian curves.
Curves from Motion, Motion from Curves
2000-01-01
tautochrone and brachistochrone properties. To Descartes, however, the rectification of curves such as the spiral (3) and the cycloid (4) was suspect - they...UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP012017 TITLE: Curves from Motion, Motion from Curves DISTRIBUTION...Approved for public release, distribution unlimited This paper is part of the following report: TITLE: International Conference on Curves and Surfaces [4th
Jang, Ho-Jun; Park, Sang-Don; Park, Hyun Woo; Suh, Jon; Oh, Pyung Chun; Moon, Jeonggeun; Lee, Kyounghoon; Kang, Woong Chol; Kwon, Sung Woo; Kim, Tae-Hoon
2017-06-01
Compared with dual antiplatelet therapy including aspirin and clopidogrel, triple antiplatelet therapy including cilostazol has a mortality benefit in patients with ST-segment elevation myocardial infarction. However, whether the mortality benefit persists in elderly patients is not clear. From 2007 to 2014, 1278 patients with ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention were retrospectively analyzed. The patients were divided into four groups by age (elderly, respectively) and antiplatelet strategy (triple or dual antiplatelet therapy). We compared the mortality rates between the triple and dual antiplatelet therapy groups. There were 1052 (male, 85%; mean age, 56.3 ± 10.4 years) patients in the young group and 241 (male, 52.7%; mean age, 80.3 ± 4.5 years) patients in the elderly group. In the young and elderly groups, 220 (20.9%) and 28 (12.3%) patients were treated with triple antiplatelet therapy. During a 1-year follow-up period, 80 patients died (4.2% in the young group vs. 15.5% in the elderly group). Kaplan-Meier survival analysis revealed that triple antiplatelet therapy was associated with a lower mortality rate in the young group (log-rank, p = 0.005). Although there were more angiographic high-risk patients in the elderly group, similar mortality rates were reported (log-rank, p = 0.803) without increased bleeding rates (1 vs. 3.6% in the elderly group, p = 0.217). Triple antiplatelet therapy might be a better antiplatelet regimen than dual antiplatelet therapy for patients with ST-segment elevation myocardial infarction. Although this benefit was strong in patients aged elderly patients (aged ≥75 years).
2002-01-01
The Atlas of Stress-Strain Curves, Second Edition is substantially bigger in page dimensions, number of pages, and total number of curves than the previous edition. It contains over 1,400 curves, almost three times as many as in the 1987 edition. The curves are normalized in appearance to aid making comparisons among materials. All diagrams include metric (SI) units, and many also include U.S. customary units. All curves are captioned in a consistent format with valuable information including (as available) standard designation, the primary source of the curve, mechanical properties (including hardening exponent and strength coefficient), condition of sample, strain rate, test temperature, and alloy composition. Curve types include monotonic and cyclic stress-strain, isochronous stress-strain, and tangent modulus. Curves are logically arranged and indexed for fast retrieval of information. The book also includes an introduction that provides background information on methods of stress-strain determination, on...
Multiphasic growth curve analysis.
Koops, W.J.
1986-01-01
Application of a multiphasic growth curve is demonstrated with 4 data sets, adopted from literature. The growth curve used is a summation of n logistic growth functions. Human height growth curves of this type are known as "double logistic" (n = 2) and "triple logistic" (n = 3) growth curves (Bock
Vo, Martin
2017-08-01
Light Curves Classifier uses data mining and machine learning to obtain and classify desired objects. This task can be accomplished by attributes of light curves or any time series, including shapes, histograms, or variograms, or by other available information about the inspected objects, such as color indices, temperatures, and abundances. After specifying features which describe the objects to be searched, the software trains on a given training sample, and can then be used for unsupervised clustering for visualizing the natural separation of the sample. The package can be also used for automatic tuning parameters of used methods (for example, number of hidden neurons or binning ratio). Trained classifiers can be used for filtering outputs from astronomical databases or data stored locally. The Light Curve Classifier can also be used for simple downloading of light curves and all available information of queried stars. It natively can connect to OgleII, OgleIII, ASAS, CoRoT, Kepler, Catalina and MACHO, and new connectors or descriptors can be implemented. In addition to direct usage of the package and command line UI, the program can be used through a web interface. Users can create jobs for ”training” methods on given objects, querying databases and filtering outputs by trained filters. Preimplemented descriptors, classifier and connectors can be picked by simple clicks and their parameters can be tuned by giving ranges of these values. All combinations are then calculated and the best one is used for creating the filter. Natural separation of the data can be visualized by unsupervised clustering.
Computational aspects of algebraic curves
Shaska, Tanush
2005-01-01
The development of new computational techniques and better computing power has made it possible to attack some classical problems of algebraic geometry. The main goal of this book is to highlight such computational techniques related to algebraic curves. The area of research in algebraic curves is receiving more interest not only from the mathematics community, but also from engineers and computer scientists, because of the importance of algebraic curves in applications including cryptography, coding theory, error-correcting codes, digital imaging, computer vision, and many more.This book cove
CYCLING CURVES AND THEIR APPLICATIONS
Directory of Open Access Journals (Sweden)
RAICU Lucian
2015-06-01
Full Text Available This paper proposes an analysis of the cyclic curves that can be considered as some of the most important regarding their applications in science, technique, design, architecture and art. These curves include the following: cycloid, epicycloid, hypocycloid, spherical cycloid and special cases thereof. In the first part of the paper the main curves of cycloids family are presented with their methods of generating and setting parametric equations. In the last part some of cycloid applications are highlighted in different areas of science, technology and art.
Differential geometry and topology of curves
Animov, Yu
2001-01-01
Differential geometry is an actively developing area of modern mathematics. This volume presents a classical approach to the general topics of the geometry of curves, including the theory of curves in n-dimensional Euclidean space. The author investigates problems for special classes of curves and gives the working method used to obtain the conditions for closed polygonal curves. The proof of the Bakel-Werner theorem in conditions of boundedness for curves with periodic curvature and torsion is also presented. This volume also highlights the contributions made by great geometers. past and present, to differential geometry and the topology of curves.
Cubic spline functions for curve fitting
Young, J. D.
1972-01-01
FORTRAN cubic spline routine mathematically fits curve through given ordered set of points so that fitted curve nearly approximates curve generated by passing infinite thin spline through set of points. Generalized formulation includes trigonometric, hyperbolic, and damped cubic spline fits of third order.
Troppan, K T; Schlick, K; Deutsch, A; Melchardt, T; Egle, A; Stojakovic, T; Beham-Schmid, C; Weiss, L; Neureiter, D; Wenzl, K; Greil, R; Neumeister, P; Pichler, M
2014-07-08
High levels of C-reactive protein (CRP), an acute phase protein, proofed being associated with decreased clinical outcome in small-scale studies in diffuse large B-cell lymphoma (DLBCL). The aim of this study was to evaluate the prognostic impact of pretreatment CRP levels on overall survival (OS) and disease-free survival (DFS) in a large bicentre study of DLBCL patients. Data from 477 DLBCL patients, diagnosed and treated between 2004 and 2013 at two Austrian centres, were evaluated retrospectively. The prognostic influence of CRP and other factors, including age, tumour stage, and revised International Prognostic Index (R-IPI) on 5-year OS and 5-year DFS, were studied by Kaplan-Meier curves as well as univariate and multivariate Cox regression models. Influence of CRP on the predictive accuracy of the R-IPI score was determined by the Harrell concordance index. Kaplan-Meier curves revealed elevated CRP as a factor for decreased 5-year OS and DFS in DLBCL patients (PIPI score and 0.79 when CRP was added. In the present study, we demonstrated high CRP levels at diagnosis of DLBCL as an independent poor prognostic factor for clinical outcome. Adding CRP to the well-established prognostic models such as the R-IPI score might improve their predictive ability.
Directory of Open Access Journals (Sweden)
Janusz Charatonik
1991-11-01
Full Text Available Results concerning contractibility of curves (equivalently: of dendroids are collected and discussed in the paper. Interrelations tetween various conditions which are either sufficient or necessary for a curve to be contractible are studied.
Indian Academy of Sciences (India)
In this article some Peano curves are exhibited and some of their recent applications are dis- cussed. A C++ program to draw the Hilbert curve approximately is given. 1. Introduction. A 'continuous curve' in the plane is usually defined as the path traced by a moving point (x (t), Y (t)) as t runs over an interval of the real line, ...
Indian Academy of Sciences (India)
Institute, Calcutta. Apart from mathematics, he likes painting and reading. Unlike most others he dislikes computers. Ritabrata Munshi. Introduction. In this two-part article we will consider one of the classi- cal theorems of mathematics, the Jordan curve theorem. It states that a simple closed curve (i.e., a closed curve which.
Nonlinear mechanics of rigidifying curves.
Al Mosleh, Salem; Santangelo, Christian
2017-07-01
Thin shells are characterized by a high cost of stretching compared to bending. As a result isometries of the midsurface of a shell play a crucial role in their mechanics. In turn, curves on the midsurface with zero normal curvature play a critical role in determining the number and behavior of isometries. In this paper, we show how the presence of these curves results in a decrease in the number of linear isometries. Paradoxically, shells are also known to continuously fold more easily across these rigidifying curves than other curves on the surface. We show how including nonlinearities in the strain can explain these phenomena and demonstrate folding isometries with explicit solutions to the nonlinear isometry equations. In addition to explicit solutions, exact geometric arguments are given to validate and guide our analysis in a coordinate-free way.
DEFF Research Database (Denmark)
Bernstein, Daniel J.; Birkner, Peter; Lange, Tanja
2013-01-01
This paper introduces EECM-MPFQ, a fast implementation of the elliptic-curve method of factoring integers. EECM-MPFQ uses fewer modular multiplications than the well-known GMP-ECM software, takes less time than GMP-ECM, and finds more primes than GMP-ECM. The main improvements above the modular......-arithmetic level are as follows: (1) use Edwards curves instead of Montgomery curves; (2) use extended Edwards coordinates; (3) use signed-sliding-window addition-subtraction chains; (4) batch primes to increase the window size; (5) choose curves with small parameters and base points; (6) choose curves with large...
Regional Marginal Abatement Cost Curves for NOx
U.S. Environmental Protection Agency — Data underlying the figures included in the manuscript "Marginal abatement cost curve for NOx incorporating controls, renewable electricity, energy efficiency and...
Calibration curves for biological dosimetry
International Nuclear Information System (INIS)
Guerrero C, C.; Brena V, M. . E-mail cgc@nuclear.inin.mx
2004-01-01
The generated information by the investigations in different laboratories of the world, included the ININ, in which settles down that certain class of chromosomal leisure it increases in function of the dose and radiation type, has given by result the obtaining of calibrated curves that are applied in the well-known technique as biological dosimetry. In this work is presented a summary of the work made in the laboratory that includes the calibrated curves for gamma radiation of 60 Cobalt and X rays of 250 k Vp, examples of presumed exposure to ionizing radiation, resolved by means of aberration analysis and the corresponding dose estimate through the equations of the respective curves and finally a comparison among the dose calculations in those people affected by the accident of Ciudad Juarez, carried out by the group of Oak Ridge, USA and those obtained in this laboratory. (Author)
Rational points on elliptic curves
Silverman, Joseph H
2015-01-01
The theory of elliptic curves involves a pleasing blend of algebra, geometry, analysis, and number theory. This book stresses this interplay as it develops the basic theory, thereby providing an opportunity for advanced undergraduates to appreciate the unity of modern mathematics. At the same time, every effort has been made to use only methods and results commonly included in the undergraduate curriculum. This accessibility, the informal writing style, and a wealth of exercises make Rational Points on Elliptic Curves an ideal introduction for students at all levels who are interested in learning about Diophantine equations and arithmetic geometry. Most concretely, an elliptic curve is the set of zeroes of a cubic polynomial in two variables. If the polynomial has rational coefficients, then one can ask for a description of those zeroes whose coordinates are either integers or rational numbers. It is this number theoretic question that is the main subject of this book. Topics covered include the geometry and ...
Magnetism in curved geometries
Streubel, Robert
Deterministically bending and twisting two-dimensional structures in the three-dimensional (3D) space provide means to modify conventional or to launch novel functionalities by tailoring curvature and 3D shape. The recent developments of 3D curved magnetic geometries, ranging from theoretical predictions over fabrication to characterization using integral means as well as advanced magnetic tomography, will be reviewed. Theoretical works predict a curvature-induced effective anisotropy and effective Dzyaloshinskii-Moriya interaction resulting in a vast of novel effects including magnetochiral effects (chirality symmetry breaking) and topologically induced magnetization patterning. The remarkable development of nanotechnology, e.g. preparation of high-quality extended thin films, nanowires and frameworks via chemical and physical deposition as well as 3D nano printing, has granted first insights into the fundamental properties of 3D shaped magnetic objects. Optimizing magnetic and structural properties of these novel 3D architectures demands new investigation methods, particularly those based on vector tomographic imaging. Magnetic neutron tomography and electron-based 3D imaging, such as electron holography and vector field electron tomography, are well-established techniques to investigate macroscopic and nanoscopic samples, respectively. At the mesoscale, the curved objects can be investigated using the novel method of magnetic X-ray tomography. In spite of experimental challenges to address the appealing theoretical predictions of curvature-induced effects, those 3D magnetic architectures have already proven their application potential for life sciences, targeted delivery, realization of 3D spin-wave filters, and magneto-encephalography devices, to name just a few. DOE BES MSED (DE-AC02-05-CH11231).
Glioblastoma: does the pre-treatment geometry matter? A postcontrast T1 MRI-based study
International Nuclear Information System (INIS)
Perez-Beteta, Julian; Martinez-Gonzalez, Alicia; Molina, David; Amo-Salas, Mariano; Luque, Belen; Perez-Garcia, Victor M.; Arregui, Elena; Calvo, Manuel; Borras, Jose M.; Lopez, Carlos; Claramonte, Marta; Barcia, Juan A.; Iglesias, Lidia; Avecillas, Josue; Albillo, David; Navarro, Miguel; Villanueva, Jose M.; Paniagua, Juan C.; Perez-Romasanta, Luis; Martino, Juan; Velasquez, Carlos; Asenjo, Beatriz; Benavides, Manuel; Herruzo, Ismael; Delgado, Maria del Carmen; Valle, Ana del; Falkov, Anthony; Schucht, Philippe; Arana, Estanislao
2017-01-01
The potential of a tumour's volumetric measures obtained from pretreatment MRI sequences of glioblastoma (GBM) patients as predictors of clinical outcome has been controversial. Mathematical models of GBM growth have suggested a relation between a tumour's geometry and its aggressiveness. A multicenter retrospective clinical study was designed to study volumetric and geometrical measures on pretreatment postcontrast T1 MRIs of 117 GBM patients. Clinical variables were collected, tumours segmented, and measures computed including: contrast enhancing (CE), necrotic, and total volumes; maximal tumour diameter; equivalent spherical CE width and several geometric measures of the CE ''rim''. The significance of the measures was studied using proportional hazards analysis and Kaplan-Meier curves. Kaplan-Meier and univariate Cox survival analysis showed that total volume [p = 0.034, Hazard ratio (HR) = 1.574], CE volume (p = 0.017, HR = 1.659), spherical rim width (p = 0.007, HR = 1.749), and geometric heterogeneity (p = 0.015, HR = 1.646) were significant parameters in terms of overall survival (OS). Multivariable Cox analysis for OS provided the later two parameters as age-adjusted predictors of OS (p = 0.043, HR = 1.536 and p = 0.032, HR = 1.570, respectively). Patients with tumours having small geometric heterogeneity and/or spherical rim widths had significantly better prognosis. These novel imaging biomarkers have a strong individual and combined prognostic value for GBM patients. (orig.)
Glioblastoma: does the pre-treatment geometry matter? A postcontrast T1 MRI-based study
Energy Technology Data Exchange (ETDEWEB)
Perez-Beteta, Julian; Martinez-Gonzalez, Alicia; Molina, David; Amo-Salas, Mariano; Luque, Belen; Perez-Garcia, Victor M. [Universidad de Castilla-La Mancha, Laboratory of Mathematical Oncology, Edificio Politecnico, Instituto de Matematica Aplicada a la Ciencia y la Ingenieria, Ciudad Real (Spain); Arregui, Elena; Calvo, Manuel; Borras, Jose M.; Lopez, Carlos; Claramonte, Marta [Hospital General de Ciudad Real, Ciudad Real (Spain); Barcia, Juan A.; Iglesias, Lidia; Avecillas, Josue [Hospital Clinico San Carlos, Madrid (Spain); Albillo, David; Navarro, Miguel; Villanueva, Jose M.; Paniagua, Juan C.; Perez-Romasanta, Luis [Hospital Universitario de Salamanca, Salamanca (Spain); Martino, Juan; Velasquez, Carlos [Hospital Marques de Valdecilla, Santander (Spain); Asenjo, Beatriz; Benavides, Manuel; Herruzo, Ismael [Hospital Carlos Haya, Malaga (Spain); Delgado, Maria del Carmen; Valle, Ana del [Universidad de Sevilla, Facultad de Matematicas, Sevilla (Spain); Falkov, Anthony [Auckland Radiation Oncology, Auckland (New Zealand); Schucht, Philippe [Bern Inselspital, Neurosurgery Department, Bern (Switzerland); Arana, Estanislao [Instituto Valenciano de Oncologia, Valencia (Spain)
2017-03-15
The potential of a tumour's volumetric measures obtained from pretreatment MRI sequences of glioblastoma (GBM) patients as predictors of clinical outcome has been controversial. Mathematical models of GBM growth have suggested a relation between a tumour's geometry and its aggressiveness. A multicenter retrospective clinical study was designed to study volumetric and geometrical measures on pretreatment postcontrast T1 MRIs of 117 GBM patients. Clinical variables were collected, tumours segmented, and measures computed including: contrast enhancing (CE), necrotic, and total volumes; maximal tumour diameter; equivalent spherical CE width and several geometric measures of the CE ''rim''. The significance of the measures was studied using proportional hazards analysis and Kaplan-Meier curves. Kaplan-Meier and univariate Cox survival analysis showed that total volume [p = 0.034, Hazard ratio (HR) = 1.574], CE volume (p = 0.017, HR = 1.659), spherical rim width (p = 0.007, HR = 1.749), and geometric heterogeneity (p = 0.015, HR = 1.646) were significant parameters in terms of overall survival (OS). Multivariable Cox analysis for OS provided the later two parameters as age-adjusted predictors of OS (p = 0.043, HR = 1.536 and p = 0.032, HR = 1.570, respectively). Patients with tumours having small geometric heterogeneity and/or spherical rim widths had significantly better prognosis. These novel imaging biomarkers have a strong individual and combined prognostic value for GBM patients. (orig.)
Indian Academy of Sciences (India)
mathematics and computer applications for the last 20 years. He has been a National Science. Talent awardee of. NCERT in mathematics. GENERAL I ARTICLE. Space-filling Curves. ReMittal. In this article some Peano curves are exhibited and some of their recent applications are dis- cussed. A C++ program to draw the ...
Tempo curves considered harmful
Desain, P.; Honing, H.
1993-01-01
In the literature of musicology, computer music research and the psychology of music, timing or tempo measurements are mostly presented in the form of continuous curves. The notion of these tempo curves is dangerous, despite its widespread use, because it lulls its users into the false impression
DEFF Research Database (Denmark)
Federici, Paolo; Georgieva Yankova, Ginka
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to a draft of IEC 61400-12-1 Ed.2.......The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to a draft of IEC 61400-12-1 Ed.2....
GEOMETRIC PROGRESSIONS ON ELLIPTIC CURVES.
Ciss, Abdoul Aziz; Moody, Dustin
2017-01-01
In this paper, we look at long geometric progressions on different model of elliptic curves, namely Weierstrass curves, Edwards and twisted Edwards curves, Huff curves and general quartics curves. By a geometric progression on an elliptic curve, we mean the existence of rational points on the curve whose x -coordinate (or y -coordinate) are in geometric progression. We find infinite families of twisted Edwards curves and Huff curves with geometric progressions of length 5, an infinite family of Weierstrass curves with 8 term progressions, as well as infinite families of quartic curves containing 10-term geometric progressions.
On the Quaternionic Focal Curves
Directory of Open Access Journals (Sweden)
Nurten (BAYRAK GÜRSES
2017-06-01
Full Text Available In this study, a brief summary about quaternions and quaternionic curves are firstly presented. Also, the definition of focal curve is given. The focal curve of a smooth curve consists of the centers of its osculating hypersphere. By using this definition and the quaternionic osculating hyperspheres of these curves, the quaternionic focal curves in the spaces $\\Q$ and $\\Q_\
Directory of Open Access Journals (Sweden)
Paulo Prochno
2004-07-01
Full Text Available Learning curves have been studied for a long time. These studies provided strong support to the hypothesis that, as organizations produce more of a product, unit costs of production decrease at a decreasing rate (see Argote, 1999 for a comprehensive review of learning curve studies. But the organizational mechanisms that lead to these results are still underexplored. We know some drivers of learning curves (ADLER; CLARK, 1991; LAPRE et al., 2000, but we still lack a more detailed view of the organizational processes behind those curves. Through an ethnographic study, I bring a comprehensive account of the first year of operations of a new automotive plant, describing what was taking place on in the assembly area during the most relevant shifts of the learning curve. The emphasis is then on how learning occurs in that setting. My analysis suggests that the overall learning curve is in fact the result of an integration process that puts together several individual ongoing learning curves in different areas throughout the organization. In the end, I propose a model to understand the evolution of these learning processes and their supporting organizational mechanisms.
U.S. Environmental Protection Agency — an UV calibration curve for SRHA quantitation. This dataset is associated with the following publication: Chang, X., and D. Bouchard. Surfactant-Wrapped Multiwalled...
Directory of Open Access Journals (Sweden)
Kožul Nataša
2014-01-01
Full Text Available In the broadest sense, yield curve indicates the market's view of the evolution of interest rates over time. However, given that cost of borrowing it closely linked to creditworthiness (ability to repay, different yield curves will apply to different currencies, market sectors, or even individual issuers. As government borrowing is indicative of interest rate levels available to other market players in a particular country, and considering that bond issuance still remains the dominant form of sovereign debt, this paper describes yield curve construction using bonds. The relationship between zero-coupon yield, par yield and yield to maturity is given and their usage in determining curve discount factors is described. Their usage in deriving forward rates and pricing related derivative instruments is also discussed.
Indian Academy of Sciences (India)
We had defined when an arc is said to cross a circle. We broaden the definition of crossing as follows: Definition: Suppose f is a piece-wise circular simple closed curve and, is a piece-wise circular arc. Suppose ..... curve formed by p' pp", q' qq", part of r between p' and q' and part of r between pI! and q", as shown (Figures 6 ...
DEFF Research Database (Denmark)
Georgieva Yankova, Ginka; Federici, Paolo
This report describes power curve measurements carried out on a given turbine in a chosen period. The measurements are carried out in accordance to IEC 61400-12-1 Ed. 1 and FGW Teil 2.......This report describes power curve measurements carried out on a given turbine in a chosen period. The measurements are carried out in accordance to IEC 61400-12-1 Ed. 1 and FGW Teil 2....
Archaeomagnetic SV curve for Belgium
Ech-chakrouni, Souad; Hus, Jozef
2017-04-01
Archaeomagnetic secular variation curves have been established for different countries in Europe, especially when different archeological sites are more or less uniformly distributed in time are available. The disadvantage in that case is that data had to be relocated to a single reference site. The proximity of the reference locality Paris to Belgium makes that we used the French archaeomagnetic SV curve for the last three millennia up to the present for archaeomagnetic dating undated baked structures. In total, 85 baked structures have been examined, unearthed in 24 archaeological sites of the territory of Belgium. The ChRM of each sample was obtained by principal component analysis for at least three demagnetisation steps (Kirschvink 1980). Except for some outliers, the ChRM directions are very coherent with a high confidence factor (α95archaeomagnetism. At present, only six baked structures were dated radiometrically and may be considered as reference data for a limited area about 30500 km2 in Western Europe. The ultimate aim is to construct an archaeomagnetic SV curve for Belgium with Uccle as reference locality, where the first measurement of the geomagnetic field was done in 1895. This curve would include all the available reference data in a radius of about 500 km around Uccle. Keywords: secular variation, archaeomagnetic dating, Belgium.
Statistical analysis of surgical pathology data using the R program.
Cuff, Justin; Higgins, John P T
2012-05-01
An understanding of statistics is essential for analysis of many types of data including data sets typically reported in surgical pathology research papers. Fortunately, a relatively small number of statistical tests apply to data relevant to surgical pathologists. An understanding of when to apply these tests would greatly benefit surgical pathologists who read and/or write papers. In this review, we show how the publicly available statistical program R can be used to analyze recently published surgical pathology papers to replicate the p-values and survival curves presented in these papers. Areas covered include: T-test, chi-square and Fisher exact tests of proportionality, Kaplan-Meier survival curves, the log rank test, and Cox proportional hazards.
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Vesth, Allan
This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here, the refere......This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here......, the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...
Complementary curves of descent
Mungan, Carl E.; Lipscombe, Trevor C.
2013-01-01
The shapes of two wires in a vertical plane with the same starting and ending points are described as complementary curves of descent if beads frictionlessly slide down both of them in the same time, starting from rest. Every analytic curve has a unique complement, except for a cycloid (solution of the brachistochrone problem), which is self complementary. A striking example is a straight wire whose complement is a lemniscate of Bernoulli. Alternatively, the wires can be tracks down which round objects undergo a rolling race. The level of presentation is appropriate for an intermediate undergraduate course in classical mechanics.
Groot, L.F.M.|info:eu-repo/dai/nl/073642398
2008-01-01
The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across
Paulton, Richard J. L.
1991-01-01
A procedure that allows students to view an entire bacterial growth curve during a two- to three-hour student laboratory period is described. Observations of the lag phase, logarithmic phase, maximum stationary phase, and phase of decline are possible. A nonpathogenic, marine bacterium is used in the investigation. (KR)
African Journals Online (AJOL)
Adele
Introduction. Both the Unique™ LMA, and lately the Cobra™ PLA, is available in most of the larger state hospitals in South Africa. This study's objective is to evaluate and compare the learning curves for insertion of these two single-use airway devices. This is to ascertain which of these two devices is easier and safer to ...
DEFF Research Database (Denmark)
Kock, Carsten Weber; Vesth, Allan
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....
DEFF Research Database (Denmark)
Federici, Paolo; Kock, Carsten Weber
This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Villanueva, Héctor
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine...
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Kock, Carsten Weber
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....
DEFF Research Database (Denmark)
Georgieva Yankova, Ginka; Villanueva, Héctor
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present anal...
DEFF Research Database (Denmark)
Villanueva, Héctor; Vesth, Allan
This report describes the power curve measurements carried out on a given wind turbine in a chosen period. The measurements were carried out following the measurement procedure in the draft of IEC 61400-12-1 Ed.2 [1], with some deviations mostly regarding uncertainty calculation. Here, the refere...
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Villanueva, Héctor
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present anal...
Textbook Factor Demand Curves.
Davis, Joe C.
1994-01-01
Maintains that teachers and textbook graphics follow the same basic pattern in illustrating changes in demand curves when product prices increase. Asserts that the use of computer graphics will enable teachers to be more precise in their graphic presentation of price elasticity. (CFR)
DEFF Research Database (Denmark)
Vesth, Allan; Kock, Carsten Weber
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine....
DEFF Research Database (Denmark)
Villanueva, Héctor; Gómez Arranz, Paula
, the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...
Power Curve Measurements, REWS
DEFF Research Database (Denmark)
Villanueva, Héctor; Gómez Arranz, Paula
, the reference wind speed used in the power curve is the equivalent wind speed obtained from lidar measurements at several heights between lower and upper blade tip, in combination with a hub height meteorological mast. The measurements have been performed using DTU’s measurement equipment, the analysis...
DEFF Research Database (Denmark)
Federici, Paolo; Kock, Carsten Weber
The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...... analyze of power performance of the turbine...
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Wagner, Rozenn
This report describes the power curve measurements performed with a nacelle LIDAR on a given wind turbine in a wind farm and during a chosen measurement period. The measurements and analysis are carried out in accordance to the guidelines in the procedure “DTU Wind Energy-E-0019” [1]. The reporting...
International Nuclear Information System (INIS)
Pan, Haoran; Koehler, Jonathan
2007-01-01
Learning curves have recently been widely adopted in climate-economy models to incorporate endogenous change of energy technologies, replacing the conventional assumption of an autonomous energy efficiency improvement. However, there has been little consideration of the credibility of the learning curve. The current trend that many important energy and climate change policy analyses rely on the learning curve means that it is of great importance to critically examine the basis for learning curves. Here, we analyse the use of learning curves in energy technology, usually implemented as a simple power function. We find that the learning curve cannot separate the effects of price and technological change, cannot reflect continuous and qualitative change of both conventional and emerging energy technologies, cannot help to determine the time paths of technological investment, and misses the central role of R and D activity in driving technological change. We argue that a logistic curve of improving performance modified to include R and D activity as a driving variable can better describe the cost reductions in energy technologies. Furthermore, we demonstrate that the top-down Leontief technology can incorporate the bottom-up technologies that improve along either the learning curve or the logistic curve, through changing input-output coefficients. An application to UK wind power illustrates that the logistic curve fits the observed data better and implies greater potential for cost reduction than the learning curve does. (author)
Birth interval and its predictors among married women in Dabat ...
African Journals Online (AJOL)
2008-12-30
Birth intervals (time between two successive live births) if short are associated with diverse complications. We assessed birth interval and its predictors among 613 married women who gave birth from January 1 to December 30, 2008. Data were collected in April 2012. Life table and Kaplan-Meier curve were used to ...
Epilepsy in Rett syndrome--lessons from the Rett networked database
DEFF Research Database (Denmark)
Nissenkorn, Andreea; Levy-Drummer, Rachel S; Bondi, Ori
2015-01-01
collected. Statistical analysis was done using the IBM SPSS Version 21 software, logistic regression, and Kaplan-Meier survival curves. RESULTS: Epilepsy was present in 68.1% of the patients, with uncontrolled seizures in 32.6% of the patients with epilepsy. Mean age of onset of epilepsy was 4...
DEFF Research Database (Denmark)
Høgdall, Claus K; Christensen, Ib J; Stephens, Ross W
2002-01-01
activator (uPAR) and carcinoembryonic antigen (CEA). Significantly shorter survival was found for patients with TN levels below a cut-off point of 7.5 mg/l compared to patients with levels above, as illustrated by Kaplan-Meier curves. By Cox analyses, log TN, log soluble uPAR as well as log CEA were found...
DEFF Research Database (Denmark)
Omland, L H; Jepsen, P; Skinhøj, P
2009-01-01
, four control HCV patients without HIV were matched on age, gender and year of HCV diagnosis. Data on comorbidity, drug abuse, alcoholism and date of death were extracted from two healthcare databases. We constructed Kaplan-Meier curves and used Cox regression analyses to estimate mortality rate ratios...
Approximation by planar elastic curves
DEFF Research Database (Denmark)
Brander, David; Gravesen, Jens; Nørbjerg, Toke Bjerge
2016-01-01
We give an algorithm for approximating a given plane curve segment by a planar elastic curve. The method depends on an analytic representation of the space of elastic curve segments, together with a geometric method for obtaining a good initial guess for the approximating curve. A gradient-driven...
Energy Technology Data Exchange (ETDEWEB)
Groot, L. [Utrecht University, Utrecht School of Economics, Janskerkhof 12, 3512 BL Utrecht (Netherlands)
2008-11-15
The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across countries. These tools allow policy-makers and the general public to grasp at a single glance the impact of conventional distribution rules such as equal caps or grandfathering, or more sophisticated ones, on the distribution of greenhouse gas emissions. Second, using the Samuelson rule for the optimal provision of a public good, the Pareto-optimal distribution of carbon emissions is compared with the distribution that follows if countries follow Nash-Cournot abatement strategies. It is shown that the Pareto-optimal distribution under the Samuelson rule can be approximated by the equal cap division, represented by the diagonal in the Lorenz curve diagram.
DEFF Research Database (Denmark)
Villanueva, Héctor; Gómez Arranz, Paula
This report describes the analysis carried out with data from a given turbine in a wind farm and a chosen period. The purpose of the analysis is to correlate the power output of the wind turbine to the wind speed measured by a nacelle-mounted anemometer. The measurements and analysis are not perf......This report describes the analysis carried out with data from a given turbine in a wind farm and a chosen period. The purpose of the analysis is to correlate the power output of the wind turbine to the wind speed measured by a nacelle-mounted anemometer. The measurements and analysis...... are not performed according to IEC 61400-12-1 [1]. Therefore, the results presented in this report cannot be considered a power curve according to the reference standard, and are referred to as “power curve investigation” instead. The measurements have been performed by a customer and the data analysis has been...
Directory of Open Access Journals (Sweden)
Iram Ansari
2012-01-01
Full Text Available Dilaceration is the result of a developmental anomaly in which there has been an abrupt change in the axial inclination between the crown and the root of a tooth. Dilaceration can be seen in both the permanent and deciduous dentitions, and is more commonly found in posterior teeth and in maxilla. Periapical radiographs are the most appropriate way to diagnose the presence of root dilacerations. The controlled regularly tapered preparation of the curved canals is the ultimate challenge in endodontics. Careful and meticulous technique will yield a safe and sufficient enlargement of the curved canals. This article gives a review of the literature and three interesting case reports of root dilacerations.
Kronberg, Max; Soomro, Muhammad Afzal; Top, Jaap
2017-10-01
In this note we extend the theory of twists of elliptic curves as presented in various standard texts for characteristic not equal to two or three to the remaining characteristics. For this, we make explicit use of the correspondence between the twists and the Galois cohomology set H^1\\big({G}_{\\overline{K}/K}, \\operatorname{Aut}_{\\overline{K}}(E)\\big). The results are illustrated by examples.
Transvaginal cholecystectomy learning curve.
Wood, Stephanie G; Dai, Feng; Dabu-Bondoc, Susan; Mikhael, Hosni; Vadivelu, Nalini; Duffy, Andrew; Roberts, Kurt E
2015-07-01
There are few surgeons in the United States, within private practice and academic centers, currently performing transvaginal cholecystectomies (TVC). The lack of exposure to TVC during residency or fellowship training, coupled with a poorly defined learning curve, further limits interested surgeons who want to apply this technique to their practice. This study describes the learning curve encountered during the introduction of TVC to our academic facility. This study is an analysis of consecutive TVCs performed between August 14, 2009 and August 3, 2012 at an academic center. The TVC patients were divided into sequential quartiles (n = 15/16). The learning curve outcome was measured as the operative time of TVC patients and compared to the operative time of female laparoscopic cholecystectomy (LC) patients performed during the same time period. Sixty-one patients underwent a TVC with a mean age of 38 ± 12 years and mean BMI was 29 ± 6 kg/m(2). Sixty-seven female patients who underwent a LC with average age 41 ± 15 years and average BMI 33 ± 12 kg/m(2). The average operative time of LC patients and TVC patients was 48 ± 20 and 60 ± 17 min, respectively. Significant improvement in TVC operative times was seen between the first (n = 15 TVCs) and second quartiles (p = 0.04) and stayed relatively constant for third quartile, during which there was no statistically significant difference between the mean LC operative time for the second and third TVC quartiles The learning curve of a fellowship-trained surgeon introducing TVC to their surgical repertoire, as measured by improved operative times, can be achieved with approximately 15 cases.
Pelce, Pierre
1989-01-01
In recent years, much progress has been made in the understanding of interface dynamics of various systems: hydrodynamics, crystal growth, chemical reactions, and combustion. Dynamics of Curved Fronts is an important contribution to this field and will be an indispensable reference work for researchers and graduate students in physics, applied mathematics, and chemical engineering. The book consist of a 100 page introduction by the editor and 33 seminal articles from various disciplines.
Heterozygote PCR product melting curve prediction.
Dwight, Zachary L; Palais, Robert; Kent, Jana; Wittwer, Carl T
2014-03-01
Melting curve prediction of PCR products is limited to perfectly complementary strands. Multiple domains are calculated by recursive nearest neighbor thermodynamics. However, the melting curve of an amplicon containing a heterozygous single-nucleotide variant (SNV) after PCR is the composite of four duplexes: two matched homoduplexes and two mismatched heteroduplexes. To better predict the shape of composite heterozygote melting curves, 52 experimental curves were compared with brute force in silico predictions varying two parameters simultaneously: the relative contribution of heteroduplex products and an ionic scaling factor for mismatched tetrads. Heteroduplex products contributed 25.7 ± 6.7% to the composite melting curve, varying from 23%-28% for different SNV classes. The effect of ions on mismatch tetrads scaled to 76%-96% of normal (depending on SNV class) and averaged 88 ± 16.4%. Based on uMelt (www.dna.utah.edu/umelt/umelt.html) with an expanded nearest neighbor thermodynamic set that includes mismatched base pairs, uMelt HETS calculates helicity as a function of temperature for homoduplex and heteroduplex products, as well as the composite curve expected from heterozygotes. It is an interactive Web tool for efficient genotyping design, heterozygote melting curve prediction, and quality control of melting curve experiments. The application was developed in Actionscript and can be found online at http://www.dna.utah.edu/hets/. © 2013 WILEY PERIODICALS, INC.
Hammer, A
2017-11-01
It was 140 years ago that George von Meyer presented his anatomical diagrams of human bones to a meeting in Zurich. There he was told by Prof. Karl Culmann that the trabecular lines shown within the diagram of the upper femur closely resembled those lines of force which Culmann had determined with Graphic Statics to be passing through a curved, loaded Fairbairn crane. This drew the attention of Julius Wolff, who used this as the basis for his 'Trajectorial theory' which was widely accepted and, to date, has been the underlying basis for all biomechanical investigations of this region. Following Wolff and Culmann, the upper femur is considered to be a curved structure and is investigated as such. Unfortunately, this concept is wrong. The upper femur is not curved but is angular. It is formed by the junction of two straight bones, the femoral neck and the femoral shaft, as may be simply seen as the neck/shaft angle constructed on the antero-posterior radiograph of any normal femur. The internal trabecular bone forms only part of the load bearing structure of the femoral neck. The configuration of this trabecular substance in this region suggests that it is related specifically to the force present during flexion and extension movements of the hip joint. This being so, combined with the delayed timing of the appearance of the trabecular columns, it must be questioned as to whether the remodelling of the upper femur is in response to one or to two distinct forces.
Differential geometry curves, surfaces, manifolds
Kühnel, Wolfgang
2015-01-01
This carefully written book is an introduction to the beautiful ideas and results of differential geometry. The first half covers the geometry of curves and surfaces, which provide much of the motivation and intuition for the general theory. The second part studies the geometry of general manifolds, with particular emphasis on connections and curvature. The text is illustrated with many figures and examples. The prerequisites are undergraduate analysis and linear algebra. This new edition provides many advancements, including more figures and exercises, and-as a new feature-a good number of so
Reflected Light Curves of Extrasolar Planets
Green, D.; Matthews, J.; Kuschnig, R.; Seager, S.
The planned launches of ultra-precise photometric satellites such as MOST, COROT and MONS should provide the first opportunity to study the reflected light curves from extrasolar planets. To predict the capabilities of these missions, we have constructed a series of models of such light curves, improving upon the Monte Carlo simulations by Seager et al. (2000). These models include more realistic features such limb darkening of the star and broad band photometry. For specific models, the resulting planet light curves exhibit unique behavior with the variation of radius, inclination and presence or absence of clouds.
Sadek, Mohammad
2012-01-01
In this paper we consider genus one equations of degree $n$, namely a (generalised) binary quartic when $n=2$, a ternary cubic when $n=3$, and a pair of quaternary quadrics when $n=4$. A new definition for the minimality of genus one equations of degree $n$ over local fields is introduced. The advantage of this definition is that it does not depend on invariant theory of genus one curves. We prove that this definition coincides with the classical definition of minimality for all $n\\le4$. As a...
Learning from uncertain curves
DEFF Research Database (Denmark)
Mallasto, Anton; Feragen, Aasa
2017-01-01
We introduce a novel framework for statistical analysis of populations of nondegenerate Gaussian processes (GPs), which are natural representations of uncertain curves. This allows inherent variation or uncertainty in function-valued data to be properly incorporated in the population analysis....... Using the 2-Wasserstein metric we geometrize the space of GPs with L2 mean and covariance functions over compact index spaces. We prove uniqueness of the barycenter of a population of GPs, as well as convergence of the metric and the barycenter of their finite-dimensional counterparts. This justifies...
Neutron cross sections: Book of curves
International Nuclear Information System (INIS)
McLane, V.; Dunford, C.L.; Rose, P.F.
1988-01-01
Neuton Cross Sections: Book of Curves represents the fourth edition of what was previously known as BNL-325, Neutron Cross Sections, Volume 2, CURVES. Data is presented only for (i.e., intergrated) reaction cross sections (and related fission parameters) as a function of incident-neutron energy for the energy range 0.01 eV to 200 MeV. For the first time, isometric state production cross sections have been included. 11 refs., 4 figs
[Biomechanic principles of the sagittal compensating curve].
Kubein-Meesenburg, D; Nägerl, H; Fanghänel, J
1990-07-01
The alignment of the buccal teeth along the compensating curve is of functional importance. It is closely related with the functional gear system of anterior and posterior guidance. Measurements have shown that individual differences between masticatory systems are mainly attributable to functional parameters. Purely skeletal parameters are of comparatively little variability. The compensating curve may be regarded as a guiding element within a master gear systems which includes the gear system of anterior and posterior guidance.
DEFF Research Database (Denmark)
Desmonde, Sophie; Dicko, Fatoumata; Koueta, Fla
2014-01-01
OBJECTIVE: We describe the association between age at antiretroviral therapy (ART) initiation and 24-month CD4 cell response in West African HIV-infected children. METHODS: All HIV-infected children from the IeDEA paediatric West African cohort, initiating ART, with at least two CD4 cell count...... measurements, including one at ART initiation (baseline) were included. CD4 cell gain on ART was estimated using a multivariable linear mixed model adjusted for baseline variables: age, CD4 cell count, sex, first-line ART regimen. Kaplan-Meier survival curves and a Cox proportional hazards regression model...... compared immune recovery for age within 24 months post-ART. RESULTS: Of the 4808 children initiated on ART, 3014 were enrolled at a median age of 5.6 years; 61.2% were immunodeficient. After 12 months, children at least 4 years at baseline had significantly lower CD4 cell gains compared with children less...
The Characteristic Curves of Water
Neumaier, Arnold; Deiters, Ulrich K.
2016-09-01
In 1960, E. H. Brown defined a set of characteristic curves (also known as ideal curves) of pure fluids, along which some thermodynamic properties match those of an ideal gas. These curves are used for testing the extrapolation behaviour of equations of state. This work is revisited, and an elegant representation of the first-order characteristic curves as level curves of a master function is proposed. It is shown that Brown's postulate—that these curves are unique and dome-shaped in a double-logarithmic p, T representation—may fail for fluids exhibiting a density anomaly. A careful study of the Amagat curve (Joule inversion curve) generated from the IAPWS-95 reference equation of state for water reveals the existence of an additional branch.
Modelling curves of manufacturing feasibilities and demand
Directory of Open Access Journals (Sweden)
Soloninko K.S.
2017-03-01
Full Text Available The authors research the issue of functional properties of curves of manufacturing feasibilities and demand. Settlement of the problem, and its connection with important scientific and practical tasks. According to its nature, the market economy is unstable and is in constant movement. Economy has an effective instrument for explanation of changes in economic environment; this tool is called the modelling of economic processes. The modelling of economic processes depends first and foremost on the building of economic model which is the base for the formalization of economic process, that is, the building of mathematical model. The effective means for formalization of economic process is the creation of the model of hypothetic or imaginary economy. The building of demand model is significant for the market of goods and services. The problem includes the receiving (as the result of modelling definite functional properties of curves of manufacturing feasibilities and demand according to which one can determine their mathematical model. Another problem lies in obtaining majorant properties of curves of joint demand on the market of goods and services. Analysis of the latest researches and publications. Many domestic and foreign scientists dedicated their studies to the researches and building of the models of curves of manufacturing feasibilities and demand. In spite of considerable work of the scientists, such problems as functional properties of the curves and their practical use in modelling. The purpose of the article is to describe functional properties of curves of manufacturing feasibilities and demand on the market of goods and services on the base of modelling of their building. Scientific novelty and practical value. The theoretical regulations (for functional properties of curves of manufacturing feasibilities and demand received as a result of the present research, that is convexity, give extra practical possibilities in a microeconomic
Directory of Open Access Journals (Sweden)
Je Hyun Baekt
2000-01-01
Full Text Available A numerical study is conducted on the fully-developed laminar flow of an incompressible viscous fluid in a square duct rotating about a perpendicular axis to the axial direction of the duct. At the straight duct, the rotation produces vortices due to the Coriolis force. Generally two vortex cells are formed and the axial velocity distribution is distorted by the effect of this Coriolis force. When a convective force is weak, two counter-rotating vortices are shown with a quasi-parabolic axial velocity profile for weak rotation rates. As the rotation rate increases, the axial velocity on the vertical centreline of the duct begins to flatten and the location of vorticity center is moved near to wall by the effect of the Coriolis force. When the convective inertia force is strong, a double-vortex secondary flow appears in the transverse planes of the duct for weak rotation rates but as the speed of rotation increases the secondary flow is shown to split into an asymmetric configuration of four counter-rotating vortices. If the rotation rates are increased further, the secondary flow restabilizes to a slightly asymmetric double-vortex configuration. Also, a numerical study is conducted on the laminar flow of an incompressible viscous fluid in a 90°-bend square duct that rotates about axis parallel to the axial direction of the inlet. At a 90°-bend square duct, the feature of flow by the effect of a Coriolis force and a centrifugal force, namely a secondary flow by the centrifugal force in the curved region and the Coriolis force in the downstream region, is shown since the centrifugal force in curved region and the Coriolis force in downstream region are dominant respectively.
Quaternion orders, quadratic forms, and Shimura curves
Alsina, Montserrat
2004-01-01
Shimura curves are a far-reaching generalization of the classical modular curves. They lie at the crossroads of many areas, including complex analysis, hyperbolic geometry, algebraic geometry, algebra, and arithmetic. The text provides an introduction to the subject from a theoretic and algorithmic perspective. The main topics covered in it are Shimura curves defined over the rational number field, the construction of their fundamental domains, and the determination of their complex multiplication points. The study of complex multiplication points in Shimura curves leads to the study of families of binary quadratic forms with algebraic coefficients and to their classification by arithmetic Fuchsian groups. In this regard, the authors develop a theory full of new possibilities which parallels Gauss' theory on the classification of binary quadratic forms with integral coefficients by the action of the modular group. Each topic covered in the book begins with a theoretical discussion followed by carefully worked...
Influence of Body Mass Index on Tumor Pathology and Survival in Uterine Cancer
DEFF Research Database (Denmark)
Kristensen, Anne Bjerrum; Hare-Bruun, Helle; Høgdall, Claus Kim
2017-01-01
for uterine cancer or atypical endometrial hyperplasia (International Classification of Diseases-10 codes D070, DC549) 2005 to 2012 (n = 6003). MAIN OUTCOME MEASURES: Impact of BMI on type I and II endometrial cancer survival. MATERIALS AND METHODS: Danish Gynecological Cancer Database data on women with type...... I and II endometrial cancer were retrieved. Kaplan-Meier plot was used to illustrate differences in survival in relation to BMI. Log-rank test was used to demonstrate difference between the curves. Cox regression hazard model was used to estimate hazard ratios (HR) of the effect of BMI on overall...... survival. RESULTS: Four thousand three hundred thirty women were included. Women with type I cancer had a significantly better overall survival compared with those with type II cancer. Low BMI was associated with increased mortality in type I (HR, 2.07; 95% confidence interval [CI], 1.20-3.55), whereas...
PRAME gene expression profile in medulloblastoma
Directory of Open Access Journals (Sweden)
Tânia Maria Vulcani-Freitas
2011-02-01
Full Text Available Medulloblastoma is the most common malignant tumors of central nervous system in the childhood. The treatment is severe, harmful and, thus, has a dismal prognosis. As PRAME is present in various cancers, including meduloblastoma, and has limited expression in normal tissues, this antigen can be an ideal vaccine target for tumor immunotherapy. In order to find a potential molecular target, we investigated PRAME expression in medulloblastoma fragments and we compare the results with the clinical features of each patient. Analysis of gene expression was performed by real-time quantitative PCR from 37 tumor samples. The Mann-Whitney test was used to analysis the relationship between gene expression and clinical characteristics. Kaplan-Meier curves were used to evaluate survival. PRAME was overexpressed in 84% samples. But no statistical association was found between clinical features and PRAME overexpression. Despite that PRAME gene could be a strong candidate for immunotherapy since it is highly expressed in medulloblastomas.
Kolker, J L; Damiano, P C; Jones, M P; Dawson, D V; Caplan, D J; Armstrong, S R; Flach, S D; Kuthy, R A; Warren, J J
2004-11-01
Crowns and large amalgams protect structurally compromised teeth to various degrees in different situations. The aim of this investigation was to evaluate the survival of teeth with these two types of restorations and the factors associated with better outcomes. Retrospective administrative and chart data were used. Survival was defined and modeled as: (1) receipt of no treatment and (2) receipt of no catastrophic treatment over five- and 10-year periods. Analyses included: Kaplan-Meier survival curves, Log-Rank tests, and Cox proportional hazards regression modeling. Crowns survived longer with no treatment and with no catastrophic treatment; however, mandibular large amalgams were least likely to have survived with no treatment, and maxillary large amalgams were least likely to have survived with no catastrophic treatment. Having no adjacent teeth also decreased survival. Crowns survived longer than large amalgams, but factors such as arch type and the presence of adjacent teeth contributed to the survival of large amalgams.
Learning curves in health professions education.
Pusic, Martin V; Boutis, Kathy; Hatala, Rose; Cook, David A
2015-08-01
Learning curves, which graphically show the relationship between learning effort and achievement, are common in published education research but are not often used in day-to-day educational activities. The purpose of this article is to describe the generation and analysis of learning curves and their applicability to health professions education. The authors argue that the time is right for a closer look at using learning curves-given their desirable properties-to inform both self-directed instruction by individuals and education management by instructors.A typical learning curve is made up of a measure of learning (y-axis), a measure of effort (x-axis), and a mathematical linking function. At the individual level, learning curves make manifest a single person's progress towards competence including his/her rate of learning, the inflection point where learning becomes more effortful, and the remaining distance to mastery attainment. At the group level, overlaid learning curves show the full variation of a group of learners' paths through a given learning domain. Specifically, they make overt the difference between time-based and competency-based approaches to instruction. Additionally, instructors can use learning curve information to more accurately target educational resources to those who most require them.The learning curve approach requires a fine-grained collection of data that will not be possible in all educational settings; however, the increased use of an assessment paradigm that explicitly includes effort and its link to individual achievement could result in increased learner engagement and more effective instructional design.
Directory of Open Access Journals (Sweden)
Sergey A. Cherkis
2007-03-01
Full Text Available A typical solution of an integrable system is described in terms of a holomorphic curve and a line bundle over it. The curve provides the action variables while the time evolution is a linear flow on the curve's Jacobian. Even though the system of Nahm equations is closely related to the Hitchin system, the curves appearing in these two cases have very different nature. The former can be described in terms of some classical scattering problem while the latter provides a solution to some Seiberg-Witten gauge theory. This note identifies the setup in which one can formulate the question of relating the two curves.
Johnson, L. E.; Kim, J.; Cifelli, R.; Chandra, C. V.
2016-12-01
Potential water retention, S, is one of parameters commonly used in hydrologic modeling for soil moisture accounting. Physically, S indicates total amount of water which can be stored in soil and is expressed in units of depth. S can be represented as a change of soil moisture content and in this context is commonly used to estimate direct runoff, especially in the Soil Conservation Service (SCS) curve number (CN) method. Generally, the lumped and the distributed hydrologic models can easily use the SCS-CN method to estimate direct runoff. Changes in potential water retention have been used in previous SCS-CN studies; however, these studies have focused on long-term hydrologic simulations where S is allowed to vary at the daily time scale. While useful for hydrologic events that span multiple days, the resolution is too coarse for short-term applications such as flash flood events where S may not recover its full potential. In this study, a new method for estimating a time-variable potential water retention at hourly time-scales is presented. The methodology is applied for the Napa River basin, California. The streamflow gage at St Helena, located in the upper reaches of the basin, is used as the control gage site to evaluate the model performance as it is has minimal influences by reservoirs and diversions. Rainfall events from 2011 to 2012 are used for estimating the event-based SCS CN to transfer to S. As a result, we have derived the potential water retention curve and it is classified into three sections depending on the relative change in S. The first is a negative slope section arising from the difference in the rate of moving water through the soil column, the second is a zero change section representing the initial recovery the potential water retention, and the third is a positive change section representing the full recovery of the potential water retention. Also, we found that the soil water moving has traffic jam within 24 hours after finished first
Mwango, Albert; Stringer, Jeffrey; Ledergerber, Bruno; Mulenga, Lloyd; Bucher, Heiner C.; Westfall, Andrew O.; Calmy, Alexandra; Boulle, Andrew; Chintu, Namwinga; Egger, Matthias; Chi, Benjamin H.
2011-01-01
Background Loss to follow-up (LTFU) is common in antiretroviral therapy (ART) programmes. Mortality is a competing risk (CR) for LTFU; however, it is often overlooked in cohort analyses. We examined how the CR of death affected LTFU estimates in Zambia and Switzerland. Methods and Findings HIV-infected patients aged ≥18 years who started ART 2004–2008 in observational cohorts in Zambia and Switzerland were included. We compared standard Kaplan-Meier curves with CR cumulative incidence. We calculated hazard ratios for LTFU across CD4 cell count strata using cause-specific Cox models, or Fine and Gray subdistribution models, adjusting for age, gender, body mass index and clinical stage. 89,339 patients from Zambia and 1,860 patients from Switzerland were included. 12,237 patients (13.7%) in Zambia and 129 patients (6.9%) in Switzerland were LTFU and 8,498 (9.5%) and 29 patients (1.6%), respectively, died. In Zambia, the probability of LTFU was overestimated in Kaplan-Meier curves: estimates at 3.5 years were 29.3% for patients starting ART with CD4 cells Switzerland since only few patients died. The results from Cox and Fine and Gray models were similar: in Zambia the risk of loss to follow-up and death increased with decreasing CD4 counts at the start of ART, whereas in Switzerland there was a trend in the opposite direction, with patients with higher CD4 cell counts more likely to be lost to follow-up. Conclusions In ART programmes in low-income settings the competing risk of death can substantially bias standard analyses of LTFU. The CD4 cell count and other prognostic factors may be differentially associated with LTFU in low-income and high-income settings. PMID:22205933
Separation control on curved boundaries
Kamal Kumar, R.; Mathur, Manikandan
2017-11-01
Flow separation and its characteristics are an important consideration in the field of bluff body aerodynamics. Specifically, the location and slope of the separation, and the size of the re-circulation bubble that forms downstream of the bluff body significantly affect the resulting aerodynamic forces. Recent theories based on dynamical systems (Haller, 2004) have established criteria based on wall-based quantities that identify the location and slope of separation in unsteady flows. In this work, we adapt the closed-loop separation control algorithm proposed by Alam, Liu & Haller (2006) to curved boundaries, and demonstrate the effectiveness of the same via numerical simulations on the flow past a cylinder in the vortex-shedding regime. Using appropriately placed wall-based actuators that use inputs from shear stress sensors placed between the actuators, we demonstrate that the separation characteristics including the re-circulation bubble length, can be desirably modified.
Liquefaction Probability Curves for Surficial Geologic Units
Holzer, T. L.; Noce, T. E.; Bennett, M. J.
2009-12-01
Liquefaction probability curves that predict the probability of surface manifestations of earthquake-induced liquefaction are developed for 14 different surficial geologic deposits. The geologic units include alluvial fan, beach ridge, river delta, eolian dune, point bar, floodbasin, natural river levee, abandoned river channel, deep-water lake, lagoonal, sandy artificial fill, and valley train deposits. Probability is conditioned on earthquake magnitude and peak ground acceleration. Curves are developed for water table depths of 1.5 and 5.0 m. Probabilities were derived from complementary cumulative frequency distributions of the liquefaction potential index (LPI) that were computed from 935 cone penetration tests. Most of the curves can be fit with a 3-parameter logistic function, which facilitates computations of probability. For natural deposits with a water table at 1.5 m depth and subjected to an M7.5 earthquake with a PGA = 0.25 g, probabilities range from 0.5 for fluvial point bar, barrier island beach ridge, and deltaic deposits. Retrospective predictions of liquefaction during historical earthquakes based on the curves compare favorably to post-earthquake observations. We also have used the curves to assign ranges of liquefaction probabilities to the susceptibility categories proposed by Youd and Perkins (1978) for different geologic deposits. For the earthquake loading and conditions described above, probabilities range from 0-0.08 for low, 0.09-0.30 for moderate, 0.31-0.62 for high, to 0.63-1.00 for very high susceptibility. Liquefaction probability curves have two primary practical applications. First, the curves can be combined with seismic source characterizations to transform surficial geologic maps into probabilistic liquefaction hazard maps. Geographic specific curves are clearly desirable, but in the absence of such information, generic liquefaction probability curves provide a first approximation of liquefaction hazard. Such maps are useful both
Compliance with Supportive Periodontal Treatment in Patients with Dental Implants.
Hu, Kai-Fang; Lin, Ying-Chu; Ho, Kun-Yen; Chou, Yu-Hsiang
The need for dental implants is increasing, and supportive periodontal treatment can achieve long-term success and prevent peri-implantitis. Contributing factors to noncompliance with long-term scheduled supportive periodontal treatment remain unclear. To investigate whether demographic and clinical characteristics are associated with noncompliance, the authors analyzed data for patients who had received dental implants. The authors recruited patients participating in a supportive periodontal treatment program after receiving permanent prostheses on implants placed from 2005 to 2013. Demographic data and dental treatment histories were collected. Compliance was defined as a record of participation in a standard supportive periodontal treatment program for at least 1 year. The chi-square test, log-rank test, Kaplan-Meier survival curve, and Cox proportional hazards model were used for statistical analysis. The study included 120 patients (259 implants, 60% compliance). The two groups (compliant and noncompliant) differed significantly in frequency distributions for sex (P = .0017), educational level (P = .0325), and histories of substance use (P = .0016), periodontitis (P = .0005), and root planing or flap surgery (P = .0002). The Kaplan-Meier survival curves and log-rank test showed that increases in cumulative continuation rates were significantly associated with male sex (P = .0025); body mass index ≥ 24 kg/m² (P = .0093); and a history of periodontitis (P implant placement, root planing or flap surgery was the crucial factor in determining compliance with supportive periodontal treatment. However, well-designed large-scale studies with a larger sample size are needed to confirm the findings of this study.
Beharier, Ofer; Sheiner, Eyal; Sergienko, Ruslan; Landau, Daniela; Szaingurten-Solodkin, Irit; Walfisch, Asnat
2017-12-01
To investigate whether children born with isolated single umbilical artery (iSUA) at term are at an increased risk for long-term pediatric hospitalizations due to respiratory morbidity. Design: a population-based cohort study compared the incidence of long-term, pediatric hospitalizations due to respiratory morbidity in children born with and without iSUA at term. Soroka University Medical Center. all singleton pregnancies of women who delivered between 1991 and 2013. hospitalization due to respiratory morbidity. Kaplan-Meier survival curves were used to estimate cumulative incidence of respiratory morbidity. A Cox hazards model analysis was used to establish an independent association between iSUA and pediatric respiratory morbidity of the offspring while controlling for clinically relevant confounders. The study included 232,281 deliveries. 0.3% were of newborns with iSUA (n = 766). Newborns with iSUA had a significantly higher rate of long-term respiratory morbidity compared to newborns without iSUA (7.6 vs 5.5%, p = 0.01). Using a Kaplan-Meier survival curve, newborns with iSUA had a significantly higher cumulative incidence of respiratory hospitalizations (log rank = 0.006). In the Cox model, while controlling for the maternal age, gestational age, and birthweight, iSUA at term was found to be an independent risk factor for long-term respiratory morbidity (adjusted HR = 1.39, 95% CI 1.08-1.81; p = 0.012). Newborns with iSUA are at an increased risk for long-term respiratory morbidity.
Serum Irisin Predicts Mortality Risk in Acute Heart Failure Patients
Directory of Open Access Journals (Sweden)
Shutong Shen
2017-06-01
Full Text Available Background/Aims: Irisin is a peptide hormone cleaved from a plasma membrane protein fibronectin type III domain containing protein 5 (FNDC5. Emerging studies have indicated association between serum irisin and many major chronic diseases including cardiovascular diseases. However, the role of serum irisin as a predictor for mortality risk in acute heart failure (AHF patients is not clear. Methods: AHF patients were enrolled and serum was collected at the admission and all patients were followed up for 1 year. Enzyme-linked immunosorbent assay was used to measure serum irisin levels. To explore predictors for AHF mortality, the univariate and multivariate logistic regression analysis, and receiver-operator characteristic (ROC curve analysis were used. To determine the role of serum irisin levels in predicting survival, Kaplan-Meier survival analysis was used. Results: In this study, 161 AHF patients were enrolled and serum irisin level was found to be significantly higher in patients deceased in 1-year follow-up. The univariate logistic regression analysis identified 18 variables associated with all-cause mortality in AHF patients, while the multivariate logistic regression analysis identified 2 variables namely blood urea nitrogen and serum irisin. ROC curve analysis indicated that blood urea nitrogen and the most commonly used biomarker, NT-pro-BNP, displayed poor prognostic value for AHF (AUCs ≤ 0.700 compared to serum irisin (AUC = 0.753. Kaplan-Meier survival analysis demonstrated that AHF patients with higher serum irisin had significantly higher mortality (P<0.001. Conclusion: Collectively, our study identified serum irisin as a predictive biomarker for 1-year all-cause mortality in AHF patients though large multicenter studies are highly needed.
Intersection numbers of spectral curves
Eynard, B
2011-01-01
We compute the symplectic invariants of an arbitrary spectral curve with only 1 branchpoint in terms of integrals of characteristic classes in the moduli space of curves. Our formula associates to any spectral curve, a characteristic class, which is determined by the laplace transform of the spectral curve. This is a hint to the key role of Laplace transform in mirror symmetry. When the spectral curve is y=\\sqrt{x}, the formula gives Kontsevich--Witten intersection numbers, when the spectral curve is chosen to be the Lambert function \\exp{x}=y\\exp{-y}, the formula gives the ELSV formula for Hurwitz numbers, and when one chooses the mirror of C^3 with framing f, i.e. \\exp{-x}=\\exp{-yf}(1-\\exp{-y}), the formula gives the topological vertex formula, i.e. the generating function of Gromov-Witten invariants of C^3. In some sense this formula generalizes ELSV formula, and Mumford formula.
Optimization on Spaces of Curves
DEFF Research Database (Denmark)
Møller-Andersen, Jakob
This thesis is concerned with computational and theoretical aspects of Riemannian metrics on spaces of regular curves, and their applications. It was recently proved that second order constant coefficient Sobolev metrics on curves are geodesically complete. We extend this result to the case...... of Sobolev metrics with coefficient functions depending on the length of the curve. We show how to apply this result to analyse a wide range of metrics on the submanifold of unit and constant speed curves. We present a numerical discretization of second order Sobolev metrics on the space of regular curves...... of cardiac deformations. Finally we investigate a new application of Riemannian shape analysis in shape optimization. We setup a simple elliptic model problem, and describe how to apply shape calculus to obtain directional derivatives in the manifold of planar curves. We present an implementation based...
Reflection of curved shock waves
Mölder, S.
2017-09-01
Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.
A Probabilistic Framework for Curve Evolution
DEFF Research Database (Denmark)
Dahl, Vedrana Andersen
2017-01-01
approach include ability to handle textured images, simple generalization to multiple regions, and efficiency in computation. We test our probabilistic framework in combination with parametric (snakes) and geometric (level-sets) curves. The experimental results on composed and natural images demonstrate...
MulensModel: Microlensing light curves modeling
Poleski, Radoslaw; Yee, Jennifer
2018-03-01
MulensModel calculates light curves of microlensing events. Both single and binary lens events are modeled and various higher-order effects can be included: extended source (with limb-darkening), annual microlensing parallax, and satellite microlensing parallax. The code is object-oriented and written in Python3, and requires AstroPy (ascl:1304.002).
Multivariate curve-fitting in GAUSS
Bunck, C.M.; Pendleton, G.W.
1988-01-01
Multivariate curve-fitting techniques for repeated measures have been developed and an interactive program has been written in GAUSS. The program implements not only the one-factor design described in Morrison (1967) but also includes pairwise comparisons of curves and rates, a two-factor design, and other options. Strategies for selecting the appropriate degree for the polynomial are provided. The methods and program are illustrated with data from studies of the effects of environmental contaminants on ducklings, nesting kestrels and quail.
Regular homotopy of Hurwitz curves
International Nuclear Information System (INIS)
Auroux, D; Kulikov, Vik S; Shevchishin, V V
2004-01-01
We prove that any two irreducible cuspidal Hurwitz curves C 0 adn C 1 (or, more generally, two curves with A-type singularities) in the Hirzebruch surface F N with the same homology classes and sets of singularities are regular homotopic. Moreover, they are symplectically regular homotopic if C 0 and C 1 are symplectic with respect to a compatible symplectic form
Space curves, anholonomy and nonlinearity
Indian Academy of Sciences (India)
Walker parallel transport [14] of any vector P moved ... of Fermi–Walker parallel transport to the case of a moving space curve. 4. General curve evolution equations .... ear term of the Lamb equation (eq. (34)) is just the time derivative of the total.
Incorporating experience curves in appliance standards analysis
International Nuclear Information System (INIS)
Desroches, Louis-Benoit; Garbesi, Karina; Kantner, Colleen; Van Buskirk, Robert; Yang, Hung-Chia
2013-01-01
There exists considerable evidence that manufacturing costs and consumer prices of residential appliances have decreased in real terms over the last several decades. This phenomenon is generally attributable to manufacturing efficiency gained with cumulative experience producing a certain good, and is modeled by an empirical experience curve. The technical analyses conducted in support of U.S. energy conservation standards for residential appliances and commercial equipment have, until recently, assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. This assumption does not reflect real market price dynamics. Using price data from the Bureau of Labor Statistics, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These experience curves were incorporated into recent energy conservation standards analyses for these products. Including experience curves increases the national consumer net present value of potential standard levels. In some cases a potential standard level exhibits a net benefit when considering experience, whereas without experience it exhibits a net cost. These results highlight the importance of modeling more representative market prices. - Highlights: ► Past appliance standards analyses have assumed constant equipment prices. ► There is considerable evidence of consistent real price declines. ► We incorporate experience curves for several large appliances into the analysis. ► The revised analyses demonstrate larger net present values of potential standards. ► The results imply that past standards analyses may have undervalued benefits.
Experimental simulation of closed timelike curves.
Ringbauer, Martin; Broome, Matthew A; Myers, Casey R; White, Andrew G; Ralph, Timothy C
2014-06-19
Closed timelike curves are among the most controversial features of modern physics. As legitimate solutions to Einstein's field equations, they allow for time travel, which instinctively seems paradoxical. However, in the quantum regime these paradoxes can be resolved, leaving closed timelike curves consistent with relativity. The study of these systems therefore provides valuable insight into nonlinearities and the emergence of causal structures in quantum mechanics--essential for any formulation of a quantum theory of gravity. Here we experimentally simulate the nonlinear behaviour of a qubit interacting unitarily with an older version of itself, addressing some of the fascinating effects that arise in systems traversing a closed timelike curve. These include perfect discrimination of non-orthogonal states and, most intriguingly, the ability to distinguish nominally equivalent ways of preparing pure quantum states. Finally, we examine the dependence of these effects on the initial qubit state, the form of the unitary interaction and the influence of decoherence.
Finch, Hilvan A.
1987-01-01
A device for analyzing commutating characteristics of a motor or generator includes a holder for supporting a plurality of probes adjacent a brush of the motor or generator. Measurements of electrical current characteristics in each of the probes provides information useful in analyzing operation of the machine. Methods for employing a device in accordance with the invention are also disclosed.
Light extraction block with curved surface
Levermore, Peter; Krall, Emory; Silvernail, Jeffrey; Rajan, Kamala; Brown, Julia J.
2016-03-22
Light extraction blocks, and OLED lighting panels using light extraction blocks, are described, in which the light extraction blocks include various curved shapes that provide improved light extraction properties compared to parallel emissive surface, and a thinner form factor and better light extraction than a hemisphere. Lighting systems described herein may include a light source with an OLED panel. A light extraction block with a three-dimensional light emitting surface may be optically coupled to the light source. The three-dimensional light emitting surface of the block may includes a substantially curved surface, with further characteristics related to the curvature of the surface at given points. A first radius of curvature corresponding to a maximum principal curvature k.sub.1 at a point p on the substantially curved surface may be greater than a maximum height of the light extraction block. A maximum height of the light extraction block may be less than 50% of a maximum width of the light extraction block. Surfaces with cross sections made up of line segments and inflection points may also be fit to approximated curves for calculating the radius of curvature.
Factors affecting the survival of HIV-infected children after ART ...
African Journals Online (AJOL)
admin
Major obstacles to scaling-up pediatric care include: lack of human resources and scarcity of pediatric ... the scale-up of ART access to its people since 2005. The free ART program was launched in July 2005. The .... non-parametric method called Kaplan-Meier method and the associated log-rank test (8), and a semi- ...
Effect of permanent pacemaker on mortality after transcatheter aortic valve replacement
DEFF Research Database (Denmark)
Engborg, Jonathan; Riechel-Sarup, Casper; Gerke, Oke
2017-01-01
of PPM implantation remains ambiguous. Design One hundred sixty-eight patients who underwent TAVI from 2008 to 2012 were included. Patient characteristics, ECGs and PPM data were collected through medical records. Kaplan-Meier plots and Cox regression analysis were performed. RESULTS: Forty subjects were...
Survival analysis of HIV-infected patients under antiretroviral ...
African Journals Online (AJOL)
admin
The Kaplan-. Meier method and log-rank test were used to compare the survival experience of different categories of patients. ... gender based violence. There is a claim that military personnel have a high risk of exposure to sexually transmitted diseases (STDs), including HIV/AIDS. In 1997 ... quality issue could be ensured.
Batic, D.; Nelson, S.; Nowakowski, M.
2015-05-01
We consider the motion of light on different spacetime manifolds by calculating the deflection angle, lensing properties and by probing into the possibility of bound states. The metrics in which we examine the light motion include, among other items, a general relativistic dark matter metric, a dirty black hole, and a worm hole metric, the last two inspired by noncommutative geometry. The lensing in a holographic screen metric is discussed in detail. We study also the bending of light around naked singularities like, e.g., the Janis-Newman-Winicour metric and include other cases. A generic property of light behavior in these exotic metrics is pointed out. For the standard metric like the Schwarzschild and Schwarzschild-de Sitter cases, we improve the accuracy of the lensing results for the weak and strong regimes.
Heart transplant outcomes in recipients of Centers for Disease Control (CDC) high risk donors.
Tsiouris, Athanasios; Wilson, Lynn; Sekar, Rajesh B; Mangi, Abeel A; Yun, James J
2016-12-01
A lack of donor hearts remains a major limitation of heart transplantation. Hearts from Centers for Disease Control (CDC) high-risk donors can be utilized with specific recipient consent. However, outcomes of heart transplantation with CDC high-risk donors are not well known. We sought to define outcomes, including posttransplant hepatitis and human immunodeficiency virus (HIV) status, in recipients of CDC high-risk donor hearts at our institution. All heart transplant recipients from August 2010 to December 2014 (n = 74) were reviewed. Comparison of 1) CDC high-risk donor (HRD) versus 2) standard-risk donor (SRD) groups were performed using chi-squared tests for nominal data and Wilcoxon two-sample tests for continuous variables. Survival was estimated with Kaplan-Meier curves. Of 74 heart transplant recipients reviewed, 66 (89%) received a SRD heart and eight (11%) received a CDC HRD heart. We found no significant differences in recipient age, sex, waiting list 1A status, pretransplant left ventricular assist device (LVAD) support, cytomegalovirus (CMV) status, and graft ischemia times (p = NS) between the HRD and SRD groups. All of the eight HRD were seronegative at the time of transplant. Postoperatively, there was no significant difference in rejection rates at six and 12 months posttransplant. Importantly, no HRD recipients acquired hepatitis or HIV. Survival in HRD versus SRD recipients was not significantly different by Kaplan-Meier analysis (log rank p = 0.644) at five years posttransplant. Heart transplants that were seronegative at the time of transplant had similar posttransplant graft function, rejection rates, and five-year posttransplant survival versus recipients of SRD hearts. At our institution, no cases of hepatitis or HIV occurred in HRD recipients in early follow-up. © 2016 Wiley Periodicals, Inc.
Han, Tianci; Shu, Tianci; Dong, Siyuan; Li, Peiwen; Li, Weinan; Liu, Dali; Qi, Ruiqun; Zhang, Shuguang; Zhang, Lin
2017-05-01
Decreased expression of human chemokine-like factor-like MARVEL transmembrane domain-containing 3 (CMTM3) has been identified in a number of human tumors and tumor cell lines, including gastric and testicular cancer, and PC3, CAL27 and Tca-83 cell lines. However, the association between CMTM3 expression and the clinicopathological features and prognosis of esophageal squamous cell carcinoma (ESCC) patients remains unclear. The aim of the present study was to investigate the correlation between CMTM3 expression and clinicopathological parameters and prognosis in ESCC. CMTM3 mRNA and protein expression was analyzed in ESCC and paired non-tumor tissues by quantitative real-time polymerase chain reaction, western blotting and immunohistochemical analysis. The Kaplan-Meier method was used to plot survival curves and the Cox proportional hazards regression model was also used for univariate and multivariate survival analysis. The results revealed that CMTM3 mRNA and protein expression levels were lower in 82.5% (30/40) and 75% (30/40) of ESCC tissues, respectively, when compared with matched non-tumor tissues. Statistical analysis demonstrated that CMTM3 expression was significantly correlated with lymph node metastasis (P=0.002) and clinical stage (P<0.001) in ESCC tissues. Furthermore, the survival time of ESCC patients exhibiting low CMTM3 expression was significantly shorter than that of ESCC patients exhibiting high CMTM3 expression (P=0.01). In addition, Kaplan-Meier survival analysis revealed that the overall survival time of patients exhibiting low CMTM3 expression was significantly decreased compared with patients exhibiting high CMTM3 expression (P=0.010). Cox multivariate analysis indicated that CMTM3 protein expression was an independent prognostic predictor for ESCC after resection. This study indicated that CMTM3 expression is significantly decreased in ESCC tissues and CMTM3 protein expression in resected tumors may present an effective prognostic
Directory of Open Access Journals (Sweden)
Ya-Hsu Yang
Full Text Available Patients with late-onset depression (LOD have been reported to run a higher risk of subsequent dementia. The present study was conducted to assess whether statins can reduce the risk of dementia in these patients.We used the data from National Health Insurance of Taiwan during 1996-2009. Standardized Incidence Ratios (SIRs were calculated for LOD and subsequent dementia. The criteria for LOD diagnoses included age ≥65 years, diagnosis of depression after 65 years of age, at least three service claims, and treatment with antidepressants. The time-dependent Cox proportional hazards model was applied for multivariate analyses. Propensity scores with the one-to-one nearest-neighbor matching model were used to select matching patients for validation studies. Kaplan-Meier curve estimate was used to measure the group of patients with dementia living after diagnosis of LOD.Totally 45,973 patients aged ≥65 years were enrolled. The prevalence of LOD was 12.9% (5,952/45,973. Patients with LOD showed to have a higher incidence of subsequent dementia compared with those without LOD (Odds Ratio: 2.785; 95% CI 2.619-2.958. Among patients with LOD, lipid lowering agent (LLA users (for at least 3 months had lower incidence of subsequent dementia than non-users (Hazard Ratio = 0.781, 95% CI 0.685-0.891. Nevertheless, only statins users showed to have reduced risk of dementia (Hazard Ratio = 0.674, 95% CI 0.547-0.832 while other LLAs did not, which was further validated by Kaplan-Meier estimates after we used the propensity scores with the one-to-one nearest-neighbor matching model to control the confounding factors.Statins may reduce the risk of subsequent dementia in patients with LOD.
Page curves for tripartite systems
International Nuclear Information System (INIS)
Hwang, Junha; Lee, Deok Sang; Nho, Dongju; Oh, Jeonghun; Park, Hyosub; Zoe, Heeseung; Yeom, Dong-han
2017-01-01
We investigate information flow and Page curves for tripartite systems. We prepare a tripartite system (say, A , B , and C ) of a given number of states and calculate information and entropy contents by assuming random states. Initially, every particle was in A (this means a black hole), and as time goes on, particles move to either B (this means Hawking radiation) or C (this means a broadly defined remnant, including a non-local transport of information, the last burst, an interior large volume, or a bubble universe, etc). If the final number of states of the remnant is smaller than that of Hawking radiation, then information will be stored by both the radiation and the mutual information between the radiation and the remnant, while the remnant itself does not contain information. On the other hand, if the final number of states of the remnant is greater than that of Hawking radiation, then the radiation contains negligible information, while the remnant and the mutual information between the radiation and the remnant contain information. Unless the number of states of the remnant is large enough compared to the entropy of the black hole, Hawking radiation must contain information; and we meet the menace of black hole complementarity again. Therefore, this contrasts the tension between various assumptions and candidates of the resolution of the information loss problem. (paper)
Elliptic Curves and Number Theory
Indian Academy of Sciences (India)
R. Sujatha, School of Mathematics, Tata Institute of Fundamental Research, Mumbai, INDIA
1. Aim: To explain the connection between a simple ancient problem in number theory and a deep sophisticated conjecture about Elliptic Curves. ('arithmetic Geometry'). Notation: N : set of natural numbers (1,2,3,...) ...
51Cr - erythrocyte survival curves
International Nuclear Information System (INIS)
Paiva Costa, J. de.
1982-07-01
Sixteen patients were studied, being fifteen patients in hemolytic state, and a normal individual as a witness. The aim was to obtain better techniques for the analysis of the erythrocytes, survival curves, according to the recommendations of the International Committee of Hematology. It was used the radiochromatic method as a tracer. Previously a revisional study of the International Literature was made in its aspects inherent to the work in execution, rendering possible to establish comparisons and clarify phonomena observed in cur investigation. Several parameters were considered in this study, hindering both the exponential and the linear curves. The analysis of the survival curves of the erythrocytes in the studied group, revealed that the elution factor did not present a homogeneous answer quantitatively to all, though, the result of the analysis of these curves have been established, through listed programs in the electronic calculator. (Author) [pt
Management of the learning curve
DEFF Research Database (Denmark)
Pedersen, Peter-Christian; Slepniov, Dmitrij
2016-01-01
Purpose – This paper focuses on the management of the learning curve in overseas capacity expansions. The purpose of this paper is to unravel the direct as well as indirect influences on the learning curve and to advance the understanding of how these affect its management. Design/methodology...... the dimensions of the learning process involved in a capacity expansion project and identified the direct and indirect labour influences on the production learning curve. On this basis, the study proposes solutions to managing learning curves in overseas capacity expansions. Furthermore, the paper concludes...... employs qualitative methodology and draws on a longitudinal, factory-level analysis of an in-depth case study of a Danish wind turbine manufacturer. Findings – This study goes beyond a simplistic treatment of the lead time and learning required to establish a new capacity. The authors examined...
International Nuclear Information System (INIS)
Haverkamp, U.; Wiezorek, C.; Poetter, R.
1990-01-01
Lyoluminescence dosimetry is based upon light emission during dissolution of previously irradiated dosimetric materials. The lyoluminescence signal is expressed in the dissolution glow curve. These curves begin, depending on the dissolution system, with a high peak followed by an exponentially decreasing intensity. System parameters that influence the graph of the dissolution glow curve, are, for example, injection speed, temperature and pH value of the solution and the design of the dissolution cell. The initial peak does not significantly correlate with the absorbed dose, it is mainly an effect of the injection. The decay of the curve consists of two exponential components: one fast and one slow. The components depend on the absorbed dose and the dosimetric materials used. In particular, the slow component correlates with the absorbed dose. In contrast to the fast component the argument of the exponential function of the slow component is independent of the dosimetric materials investigated: trehalose, glucose and mannitol. The maximum value, following the peak of the curve, and the integral light output are a measure of the absorbed dose. The reason for the different light outputs of various dosimetric materials after irradiation with the same dose is the differing solubility. The character of the dissolution glow curves is the same following irradiation with photons, electrons or neutrons. (author)
Hypothesized, Directly-Coded Curve Shapes in Growth Curve Analysis: An Example
Directory of Open Access Journals (Sweden)
Patricia M. Herman
2013-02-01
Full Text Available Growth curve analysis provides important informational benefits regarding intervention outcomes over time. Rarely, however, should outcome trajectories be assumed to be linear. Instead, both the shape and the slope of the growth curve can be estimated. Non-linear growth curves are usually modeled by including either higher-order time variables or orthogonal polynomial contrast codes. Each has limitations (multicollinearity with the first, a lack of coefficient interpretability with the second, and a loss of degrees of freedom with both and neither encourages direct testing of alternative hypothesized curve shapes. Especially in studies with relatively small samples it is likely to be useful to preserve as much information as possible at the individual level. This article presents a step-by-step example of the use and testing of hypothesized curve shapes in the estimation of growth curves using hierarchical linear modeling for a small intervention study. DOI: 10.2458/azu_jmmss.v3i2.16476
The advanced geometry of plane curves and their applications
Zwikker, C
2005-01-01
""Of chief interest to mathematicians, but physicists and others will be fascinated ... and intrigued by the fruitful use of non-Cartesian methods. Students ... should find the book stimulating."" - British Journal of Applied PhysicsThis study of many important curves, their geometrical properties, and their applications features material not customarily treated in texts on synthetic or analytic Euclidean geometry. Its wide coverage, which includes both algebraic and transcendental curves, extends to unusual properties of familiar curves along with the nature of lesser known curves.Informativ
TELECOMMUNICATIONS INFRASTRUCTURE AND GDP /JIPP CURVE/
Directory of Open Access Journals (Sweden)
Mariana Kaneva
2016-07-01
Full Text Available The relationship between telecommunications infrastructure and economic activity is under discussion in many scientific papers. Most of the authors use for research and analysis the Jipp curve. A lot of doubts about the correctness of the Jipp curve appear in terms of applying econometric models. The aim of this study is a review of the Jipp curve, refining the possibility of its application in modern conditions. The methodology used in the study is based on dynamic econometric models, including tests for nonstationarity and tests for causality. The focus of this study is directed to methodological problems in measuring the local density types of telecommunication networks. This study offers a specific methodology for assessing the Jipp law, through VAR-approach and Granger causality tests. It is proved that mechanical substitution of momentary aggregated variables (such as the number of subscribers of a telecommunication network at the end of the year and periodically aggregated variables (such as GDP per capita in the Jipp�s curve is methodologically wrong. Researchers have to reconsider the relationship set in the Jipp�s curve by including additional variables that characterize the Telecommunications sector and the economic activity in a particular country within a specified time period. GDP per capita should not be regarded as a single factor for the local density of telecommunications infrastructure. New econometric models studying the relationship between the investments in telecommunications infrastructure and economic development may be not only linear regression models, but also other econometric models. New econometric models should be proposed after testing and validating with sound economic theory and econometric methodology.
Considerations for reference pump curves
International Nuclear Information System (INIS)
Stockton, N.B.
1992-01-01
This paper examines problems associated with inservice testing (IST) of pumps to assess their hydraulic performance using reference pump curves to establish acceptance criteria. Safety-related pumps at nuclear power plants are tested under the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (the Code), Section 11. The Code requires testing pumps at specific reference points of differential pressure or flow rate that can be readily duplicated during subsequent tests. There are many cases where test conditions cannot be duplicated. For some pumps, such as service water or component cooling pumps, the flow rate at any time depends on plant conditions and the arrangement of multiple independent and constantly changing loads. System conditions cannot be controlled to duplicate a specific reference value. In these cases, utilities frequently request to use pump curves for comparison of test data for acceptance. There is no prescribed method for developing a pump reference curve. The methods vary and may yield substantially different results. Some results are conservative when compared to the Code requirements; some are not. The errors associated with different curve testing techniques should be understood and controlled within reasonable bounds. Manufacturer's pump curves, in general, are not sufficiently accurate to use as reference pump curves for IST. Testing using reference curves generated with polynomial least squares fits over limited ranges of pump operation, cubic spline interpolation, or cubic spline least squares fits can provide a measure of pump hydraulic performance that is at least as accurate as the Code required method. Regardless of the test method, error can be reduced by using more accurate instruments, by correcting for systematic errors, by increasing the number of data points, and by taking repetitive measurements at each data point
Growth Curves for Girls with Turner Syndrome
Directory of Open Access Journals (Sweden)
Fabio Bertapelli
2014-01-01
Full Text Available The objective of this study was to review the growth curves for Turner syndrome, evaluate the methodological and statistical quality, and suggest potential growth curves for clinical practice guidelines. The search was carried out in the databases Medline and Embase. Of 1006 references identified, 15 were included. Studies constructed curves for weight, height, weight/height, body mass index, head circumference, height velocity, leg length, and sitting height. The sample ranged between 47 and 1,565 (total = 6,273 girls aged 0 to 24 y, born between 1950 and 2006. The number of measures ranged from 580 to 9,011 (total = 28,915. Most studies showed strengths such as sample size, exclusion of the use of growth hormone and androgen, and analysis of confounding variables. However, the growth curves were restricted to height, lack of information about selection bias, limited distributional properties, and smoothing aspects. In conclusion, we observe the need to construct an international growth reference for girls with Turner syndrome, in order to provide support for clinical practice guidelines.
Curve Digitizer – A software for multiple curves digitizing
Directory of Open Access Journals (Sweden)
Florentin ŞPERLEA
2010-06-01
Full Text Available The Curve Digitizer is software that extracts data from an image file representing a graphicand returns them as pairs of numbers which can then be used for further analysis and applications.Numbers can be read on a computer screen stored in files or copied on paper. The final result is adata set that can be used with other tools such as MSEXCEL. Curve Digitizer provides a useful toolfor any researcher or engineer interested in quantifying the data displayed graphically. The image filecan be obtained by scanning a document
McCraig, Michael A.; Osinski, Gordon R.; Cloutis, Edward A.; Flemming, Roberta L.; Izawa, Matthew R. M.; Reddy, Vishnu; Fieber-Beyer, Sherry K.; Pompilio, Loredana; van der Meer, Freek; Berger, Jeffrey A.; Bramble, Michael S.; Applin, Daniel M.
2017-03-01
Spectroscopy in planetary science often provides the only information regarding the compositional and mineralogical make up of planetary surfaces. The methods employed when curve fitting and modelling spectra can be confusing and difficult to visualize and comprehend. Researchers who are new to working with spectra may find inadequate help or documentation in the scientific literature or in the software packages available for curve fitting. This problem also extends to the parameterization of spectra and the dissemination of derived metrics. Often, when derived metrics are reported, such as band centres, the discussion of exactly how the metrics were derived, or if there was any systematic curve fitting performed, is not included. Herein we provide both recommendations and methods for curve fitting and explanations of the terms and methods used. Techniques to curve fit spectral data of various types are demonstrated using simple-to-understand mathematics and equations written to be used in Microsoft Excel® software, free of macros, in a cut-and-paste fashion that allows one to curve fit spectra in a reasonably user-friendly manner. The procedures use empirical curve fitting, include visualizations, and ameliorates many of the unknowns one may encounter when using black-box commercial software. The provided framework is a comprehensive record of the curve fitting parameters used, the derived metrics, and is intended to be an example of a format for dissemination when curve fitting data.
Directory of Open Access Journals (Sweden)
Bender Ralf
2011-09-01
Full Text Available Abstract Background To assess the reporting of loss to follow-up (LTFU information in articles on randomised controlled trials (RCTs with time-to-event outcomes, and to assess whether discrepancies affect the validity of study results. Methods Literature survey of all issues of the BMJ, Lancet, JAMA, and New England Journal of Medicine published between 2003 and 2005. Eligible articles were reports of RCTs including at least one Kaplan-Meier plot. Articles were classified as "assessable" if sufficient information was available to assess LTFU. In these articles, LTFU information was derived from Kaplan-Meier plots, extracted from the text, and compared. Articles were then classified as "consistent" or "not consistent". Sensitivity analyses were performed to assess the validity of study results. Results 319 eligible articles were identified. 187 (59% were classified as "assessable", as they included sufficient information for evaluation; 140 of 319 (44% presented consistent LTFU information between the Kaplan-Meier plot and text. 47 of 319 (15% were classified as "not consistent". These 47 articles were included in sensitivity analyses. When various imputation methods were used, the results of a chi2-test applied to the corresponding 2 × 2 table changed and hence were not robust in about half of the studies. Conclusions Less than half of the articles on RCTs using Kaplan-Meier plots provide assessable and consistent LTFU information, thus questioning the validity of the results and conclusions of many studies presenting survival analyses. Authors should improve the presentation of both Kaplan-Meier plots and LTFU information, and reviewers of study publications and journal editors should critically appraise the validity of the information provided.
Laffer Curves and Home Production
Directory of Open Access Journals (Sweden)
Kotamäki Mauri
2017-06-01
Full Text Available In the earlier related literature, consumption tax rate Laffer curve is found to be strictly increasing (see Trabandt and Uhlig (2011. In this paper, a general equilibrium macro model is augmented by introducing a substitute for private consumption in the form of home production. The introduction of home production brings about an additional margin of adjustment – an increase in consumption tax rate not only decreases labor supply and reduces the consumption tax base but also allows a substitution of market goods with home-produced goods. The main objective of this paper is to show that, after the introduction of home production, the consumption tax Laffer curve exhibits an inverse U-shape. Also the income tax Laffer curves are significantly altered. The result shown in this paper casts doubt on some of the earlier results in the literature.
The New Keynesian Phillips Curve
DEFF Research Database (Denmark)
Ólafsson, Tjörvi
This paper provides a survey on the recent literature on the new Keynesian Phillips curve: the controversies surrounding its microfoundation and estimation, the approaches that have been tried to improve its empirical fit and the challenges it faces adapting to the open-economy framework. The new...... Keynesian Phillips curve has been severely criticized for poor empirical dynamics. Suggested improvements involve making some adjustments to the standard sticky price framework, e.g. introducing backwardness and real rigidities, or abandoning the sticky price model and relying on models of inattentiveness......, learning or state-dependant pricing. The introduction of openeconomy factors into the new Keynesian Phillips curve complicate matters further as it must capture the nexus between price setting, inflation and the exchange rate. This is nevertheless a crucial feature for any model to be used for inflation...
Visualizing Nonlinear Narratives with Story Curves.
Kim, Nam Wook; Bach, Benjamin; Im, Hyejin; Schriber, Sasha; Gross, Markus; Pfister, Hanspeter
2018-01-01
In this paper, we present story curves, a visualization technique for exploring and communicating nonlinear narratives in movies. A nonlinear narrative is a storytelling device that portrays events of a story out of chronological order, e.g., in reverse order or going back and forth between past and future events. Many acclaimed movies employ unique narrative patterns which in turn have inspired other movies and contributed to the broader analysis of narrative patterns in movies. However, understanding and communicating nonlinear narratives is a difficult task due to complex temporal disruptions in the order of events as well as no explicit records specifying the actual temporal order of the underlying story. Story curves visualize the nonlinear narrative of a movie by showing the order in which events are told in the movie and comparing them to their actual chronological order, resulting in possibly meandering visual patterns in the curve. We also present Story Explorer, an interactive tool that visualizes a story curve together with complementary information such as characters and settings. Story Explorer further provides a script curation interface that allows users to specify the chronological order of events in movies. We used Story Explorer to analyze 10 popular nonlinear movies and describe the spectrum of narrative patterns that we discovered, including some novel patterns not previously described in the literature. Feedback from experts highlights potential use cases in screenplay writing and analysis, education and film production. A controlled user study shows that users with no expertise are able to understand visual patterns of nonlinear narratives using story curves.
Trend analyses with river sediment rating curves
Warrick, Jonathan A.
2015-01-01
Sediment rating curves, which are fitted relationships between river discharge (Q) and suspended-sediment concentration (C), are commonly used to assess patterns and trends in river water quality. In many of these studies it is assumed that rating curves have a power-law form (i.e., C = aQb, where a and b are fitted parameters). Two fundamental questions about the utility of these techniques are assessed in this paper: (i) How well to the parameters, a and b, characterize trends in the data? (ii) Are trends in rating curves diagnostic of changes to river water or sediment discharge? As noted in previous research, the offset parameter, a, is not an independent variable for most rivers, but rather strongly dependent on b and Q. Here it is shown that a is a poor metric for trends in the vertical offset of a rating curve, and a new parameter, â, as determined by the discharge-normalized power function [C = â (Q/QGM)b], where QGM is the geometric mean of the Q values sampled, provides a better characterization of trends. However, these techniques must be applied carefully, because curvature in the relationship between log(Q) and log(C), which exists for many rivers, can produce false trends in â and b. Also, it is shown that trends in â and b are not uniquely diagnostic of river water or sediment supply conditions. For example, an increase in â can be caused by an increase in sediment supply, a decrease in water supply, or a combination of these conditions. Large changes in water and sediment supplies can occur without any change in the parameters, â and b. Thus, trend analyses using sediment rating curves must include additional assessments of the time-dependent rates and trends of river water, sediment concentrations, and sediment discharge.
Electro-Mechanical Resonance Curves
Greenslade, Thomas B.
2018-03-01
Recently I have been investigating the frequency response of galvanometers. These are direct-current devices used to measure small currents. By using a low-frequency function generator to supply the alternating-current signal and a stopwatch smartphone app to measure the period, I was able to take data to allow a resonance curve to be drawn. This is the sort of project that should provide a fascinating research experience for the introductory physics student. In this article I will discuss the galvanometers that I used in this work, and will show a resonance curve for one of them.
DEFF Research Database (Denmark)
Brücker, Herbert; Jahn, Elke J.
Based on a wage curve approach we examine the labor market effects of migration in Germany. The wage curve relies on the assumption that wages respond to a change in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously...... with a vocational degree. The wage and employment effects of migration are moderate: a 1 percent increase in the German labor force through immigration increases the aggregate unemployment rate by less than 0.1 percentage points and reduces average wages by less 0.1 percent. While native workers benefit from...... increased wages and lower unemployment, foreign workers are adversely affected....
Shock detachment from curved wedges
Mölder, S.
2017-09-01
Curved shock theory is used to show that the flow behind attached shocks on doubly curved wedges can have either positive or negative post-shock pressure gradients depending on the freestream Mach number, the wedge angle and the two wedge curvatures. Given enough wedge length, the flow near the leading edge can choke to force the shock to detach from the wedge. This local choking can preempt both the maximum deflection and the sonic criteria for shock detachment. Analytical predictions for detachment by local choking are supported by CFD results.
Maximum likelihood decay curve fits by the simplex method
International Nuclear Information System (INIS)
Gregorich, K.E.
1991-01-01
A multicomponent decay curve analysis technique has been developed and incorporated into the decay curve fitting computer code, MLDS (maximum likelihood decay by the simplex method). The fitting criteria are based on the maximum likelihood technique for decay curves made up of time binned events. The probabilities used in the likelihood functions are based on the Poisson distribution, so decay curves constructed from a small number of events are treated correctly. A simple utility is included which allows the use of discrete event times, rather than time-binned data, to make maximum use of the decay information. The search for the maximum in the multidimensional likelihood surface for multi-component fits is performed by the simplex method, which makes the success of the iterative fits extremely insensitive to the initial values of the fit parameters and eliminates the problems of divergence. The simplex method also avoids the problem of programming the partial derivatives of the decay curves with respect to all the variable parameters, which makes the implementation of new types of decay curves straightforward. Any of the decay curve parameters can be fixed or allowed to vary. Asymmetric error limits for each of the free parameters, which do not consider the covariance of the other free parameters, are determined. A procedure is presented for determining the error limits which contain the associated covariances. The curve fitting procedure in MLDS can easily be adapted for fits to other curves with any functional form. (orig.)
Dual Smarandache Curves of a Timelike Curve lying on Unit dual Lorentzian Sphere
Kahraman, Tanju; Hüseyin Ugurlu, Hasan
2016-01-01
In this paper, we give Darboux approximation for dual Smarandache curves of time like curve on unit dual Lorentzian sphere. Firstly, we define the four types of dual Smarandache curves of a timelike curve lying on dual Lorentzian sphere.
The aeolian dust accumulation curve
Goossens, D.
2001-01-01
This article presents a simple physical concept of aeolian dust accumulation, based on the behaviour of the subprocesses of dust deposition and dust erosion. The concept is tested in an aeolian dust wind tunnel. The agreement between the accumulation curve predicted by the model and the accumulation
Indian Academy of Sciences (India)
The cause-effect relationship for a wide variety of biologi- cal processes from molecular to ecosystem levels can be described by a curvilinear function called the rectangular hyperbola. Although a simple algebraic equation adequately describes this curve, biological models have generated different equations incorporating ...
Survival curves for irradiated cells
International Nuclear Information System (INIS)
Gibson, D.K.
1975-01-01
The subject of the lecture is the probability of survival of biological cells which have been subjected to ionising radiation. The basic mathematical theories of cell survival as a function of radiation dose are developed. A brief comparison with observed survival curves is made. (author)
2013-01-01
This software can be used to assist with the assessment of margin of safety for a horizontal curve. It is intended for use by engineers and technicians responsible for safety analysis or management of rural highway pavement or traffic control devices...
Ultrasonic Fetal Cephalometry: Percentiles Curve
Flamme, P.
1972-01-01
Measurements by ultrasound of the biparietal diameter of the fetal head during pregnancy are a reliable guide to fetal growth. As a ready means of comparison with the normal we constructed from 4,170 measurements in 1,394 cases a curve showing the percentiles distribution of biparietal diameters for each week of gestation. PMID:5070162
Interpolation and Polynomial Curve Fitting
Yang, Yajun; Gordon, Sheldon P.
2014-01-01
Two points determine a line. Three noncollinear points determine a quadratic function. Four points that do not lie on a lower-degree polynomial curve determine a cubic function. In general, n + 1 points uniquely determine a polynomial of degree n, presuming that they do not fall onto a polynomial of lower degree. The process of finding such a…
Gauge field configurations in curved spacetimes (II)
International Nuclear Information System (INIS)
Boutaleb-Joutei, H.; Chakrabarti, A.; Comtet, A.
1979-05-01
One continues the study of gauge field configurations in curved spaces, using the formalism and results of a previous paper. A class of static, finite action, selfdual solutions of SU(2) gauge fields on a Euclidean section of de Sitter space is presented. The action depends on a continuous parameter. The spin connection solution is obtained as a particular case and a certain passage to the limiting case of a flat space is shown to reproduce the Euclidean Prasad-Sommerfield solution. The significance and possible interest of such solutions are discussed. The results are then generalized to a non-Einstein but conformally flat space, including de Sitter space as an Einstein limit. Next Baecklund type transformations are constructed starting from selfduality constraints for such curved spaces. These transformations are applied to the above mentioned solutions. The last two sections contain remarks on solutions with a background Robinson-Bertotti metric and on static, axially symmetric solutions respectively
Geometry of curves and surfaces with Maple
Rovenski, Vladimir
2000-01-01
This concise text on geometry with computer modeling presents some elementary methods for analytical modeling and visualization of curves and surfaces. The author systematically examines such powerful tools as 2-D and 3-D animation of geometric images, transformations, shadows, and colors, and then further studies more complex problems in differential geometry. Well-illustrated with more than 350 figures---reproducible using Maple programs in the book---the work is devoted to three main areas: curves, surfaces, and polyhedra. Pedagogical benefits can be found in the large number of Maple programs, some of which are analogous to C++ programs, including those for splines and fractals. To avoid tedious typing, readers will be able to download many of the programs from the Birkhauser web site. Aimed at a broad audience of students, instructors of mathematics, computer scientists, and engineers who have knowledge of analytical geometry, i.e., method of coordinates, this text will be an excellent classroom resource...
Point- and curve-based geometric conflation
López-Vázquez, C.
2013-01-01
Geometric conflation is the process undertaken to modify the coordinates of features in dataset A in order to match corresponding ones in dataset B. The overwhelming majority of the literature considers the use of points as features to define the transformation. In this article we present a procedure to consider one-dimensional curves also, which are commonly available as Global Navigation Satellite System (GNSS) tracks, routes, coastlines, and so on, in order to define the estimate of the displacements to be applied to each object in A. The procedure involves three steps, including the partial matching of corresponding curves, the computation of some analytical expression, and the addition of a correction term in order to satisfy basic cartographic rules. A numerical example is presented. © 2013 Copyright Taylor and Francis Group, LLC.
Moduli spaces of curves and enumerative geometry via topological recursion
Lewański, D.
2017-01-01
The thesis considers several enumerative geometric problems concerning the topology of the moduli space of curves and their combinatorics. These enumerative geometric problems are analysed from different intertwined points of view and using different mathematical tools, including Hurwitz theory,
Spring, Michele D; Lin, Jessica T; Manning, Jessica E; Vanachayangkul, Pattaraporn; Somethy, Sok; Bun, Rathvicheth; Se, Youry; Chann, Soklyda; Ittiverakul, Mali; Sia-ngam, Piyaporn; Kuntawunginn, Worachet; Arsanok, Montri; Buathong, Nillawan; Chaorattanakawee, Suwanna; Gosi, Panita; Ta-aksorn, Winita; Chanarat, Nitima; Sundrakes, Siratchana; Kong, Nareth; Heng, Thay Kheang; Nou, Samon; Teja-isavadharm, Paktiya; Pichyangkul, Sathit; Phann, Sut Thang; Balasubramanian, Sujata; Juliano, Jonathan J; Meshnick, Steven R; Chour, Char Meng; Prom, Satharath; Lanteri, Charlotte A; Lon, Chanthap; Saunders, David L
2015-06-01
Dihydroartemisinin-piperaquine has been adopted as first-line artemisinin combination therapy (ACT) for multidrug-resistant Plasmodium falciparum malaria in Cambodia because of few remaining alternatives. We aimed to assess the efficacy of standard 3 day dihydroartemisinin-piperaquine treatment of uncomplicated P falciparum malaria, with and without the addition of primaquine, focusing on the factors involved in drug resistance. In this observational cohort study, we assessed 107 adults aged 18-65 years presenting to Anlong Veng District Hospital, Oddar Meanchey Province, Cambodia, with uncomplicated P falciparum or mixed P falciparum/Plasmodium vivax infection of between 1000 and 200,000 parasites per μL of blood, and participating in a randomised clinical trial in which all had received dihydroartemisinin-piperaquine for 3 days, after which they had been randomly allocated to receive either primaquine or no primaquine. The trial was halted early due to poor dihydroartemisinin-piperaquine efficacy, and we assessed day 42 PCR-corrected therapeutic efficacy (proportion of patients with recurrence at 42 days) and evidence of drug resistance from the initial cohort. We did analyses on both the intention to treat (ITT), modified ITT (withdrawals, losses to follow-up, and those with secondary outcomes [eg, new non-recrudescent malaria infection] were censored on the last day of follow-up), and per-protocol populations of the original trial. The original trial was registered with ClinicalTrials.gov, number NCT01280162. Between Dec 10, 2012, and Feb 18, 2014, we had enrolled 107 patients in the original trial. Enrolment was voluntarily halted on Feb 16, 2014, before reaching planned enrolment (n=150) because of poor efficacy. We had randomly allocated 50 patients to primaquine and 51 patients to no primaquine groups. PCR-adjusted Kaplan-Meier risk of P falciparum 42 day recrudescence was 54% (95% CI 45-63) in the modified ITT analysis population. We found two kelch13
Wang, Fei; Xu, Xi-ming; Wei, Xian-zhao; Zhu, Xiao-dong; Li, Ming
2015-07-01
Selective fusion of the thoracolumbar/lumbar (TL/L) curve is an effective method for the treatment of Lenke type 5C curves. Several studies have demonstrated that spontaneous correction of the thoracic curve does indeed occur. However, how this correction occurs after isolated posterior segmental instrumentation of the structural lumbar curve has not been well described. The aim of this study was to evaluate the response of the thoracic curve to selective TL/L curve fusion in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS) and assess the correlative clinical outcomes. Thirty-four consecutive patients with Lenke type 5C AIS were included in this study. All patients underwent selective TL/L curve instrumentation and fusion via the posterior approach. Coronal and sagittal radiographs were analyzed before surgery, at 1 week after surgery and at least 2 years after surgery. The preoperative coronal Cobb angle of the major TL/L curve was 45.4° ± 7.0°, and that of the minor thoracic curve was 25.4° ± 8.8°. The major TL/L and minor thoracic curves were corrected to postoperative angles of 9.5° ± 5.0° and 11.2° ± 5.2°, respectively, and measured 10.5° ± 6.0° and 13.4° ± 7.5° at the follow-up, respectively. The supine side-bending average Cobb angle of the thoracic curve was 9.9°. These results demonstrate satisfactory improvements because of coronal and sagittal restoration. Significant correlations were found between the preoperative and early postoperative conditions and the Cobb angle changes of the minor thoracic curve and the major TL/L curves (r = 0.42, P = 0.01). Significant correlations were also observed between the early and final follow-up postoperative conditions and the Cobb angle changes of the minor thoracic curve and the major TL/L curves (r = 0.57, P 5C AIS patients. Supine side-bending radiographs are an effective method of predicting the spontaneous correction of thoracic curves. The correction of LL is important for
Natural frequencies of the frames having curved member
International Nuclear Information System (INIS)
Tekelioglu, M.; Ozyigit, H.A.; Ridvan, H.
2001-01-01
In-plane and out-of-plane vibrations of a frame having a curved member are studied. Although the analysis is carried out on a frame having a straight and a curve beam, it can be applicable for all the frame type structures. Different end conditions are considered for the system. Rotary inertia and extensional effects are included for the curved member. Finite element method is used as analysis tool. Natural frequencies of the curved beams for different end conditions are calculated first, and then the frequencies of the frames are investigated. The transformation from local coordinates to global coordinates for curved beams needs special attention in the analysis. The results are compared with other methods. (author)
Detection of flaws below curved surfaces
International Nuclear Information System (INIS)
Elsley, R.K.; Addison, R.C.; Graham, L.J.
1983-01-01
A measurement model has been developed to describe ultrasonic measurements made with circular piston transducers in parts with flat or cylindrically curved surfaces. The model includes noise terms to describe electrical noise, scatterer noise and echo noise as well as effects of attenuation, diffraction and Fresnel loss. An experimental procedure for calibrating the noise terms of the model was developed. Experimental measurements were made on a set of known flaws located beneath a cylindrically curved surface. The model was verified by using it to correct the experimental measurements to obtain the absolute scattering amplitude of the flaws. For longitudinal wave propagation within the part, the derived scattering amplitudes were consistent with predictions at internal angles of less than 30 0 . At larger angles, focusing and aberrations caused a lack of agreement; the model needs further refinement in this case. For shear waves, it was found that the frequency for optimum flaw detection in the presence of material noise is lower than that for longitudinal waves; lower frequency measurements are currently in progress. The measurement model was then used to make preliminary predictions of the best experimental measurement technique for the detection of cracks located under cylindrically curved surfaces
Describing the learning curve for bulbar urethroplasty.
Spilotros, Marco; Malde, Sachin; Greenwell, Tamsin J
2017-12-01
Learning curves have been described for a number of urological procedures including radical prostatectomy and laparoscopic nephrectomy but rarely for urethroplasty. We describe the learning curve for bulbar urethroplasty in a single surgeon series. A retrospective case note review was performed of 91 consecutive men median age 32 years (range, 15-66 years) having bulbar urethroplasty performed by a single surgeon. Data was collected on type of urethroplasty, restricture rate (as defined by urethrogram and/or flow rate) and duration of follow up. The restricture rates were compared by quartiles and statistical analysis was by ¦Ö 2 between the first and fourth quartiles. The 91 men had 42 dorsal onlay buccal mucosal graft (Dorsal BMG), 20 BMG augmented bulbobulbar anastomotic (Augmented Rooftop) and 29 bulbobulbar anastomotic (BBA) urethroplasties performed. Median follow up was 39 months for the first quartile, 42 months for the second, 36 months for the third, and 35 months for the fourth. The restricture rate was 17% in the first quartile, 8.7% in the second and third quartiles and 4.5% in the fourth quartile. There were no restrictures noted after 24 months. There were 4 restrictures in the first quartile and 1 restricture in the fourth quartile (¦Ö 2 Plearning curve for bulbar urethroplasty with a reduced restricture rate each quartile and it may take as many as 90 cases to reach optimum restricture rates.
A catalog of special plane curves
Lawrence, J Dennis
2014-01-01
Among the largest, finest collections available-illustrated not only once for each curve, but also for various values of any parameters present. Covers general properties of curves and types of derived curves. Curves illustrated by a CalComp digital incremental plotter. 12 illustrations.
Computation of undulator tuning curves
International Nuclear Information System (INIS)
Dejus, Roger J.
1997-01-01
Computer codes for fast computation of on-axis brilliance tuning curves and flux tuning curves have been developed. They are valid for an ideal device (regular planar device or a helical device) using the Bessel function formalism. The effects of the particle beam emittance and the beam energy spread on the spectrum are taken into account. The applicability of the codes and the importance of magnetic field errors of real insertion devices are addressed. The validity of the codes has been experimentally verified at the APS and observed discrepancies are in agreement with predicted reduction of intensities due to magnetic field errors. The codes are distributed as part of the graphical user interface XOP (X-ray OPtics utilities), which simplifies execution and viewing of the results
Invariance for Single Curved Manifold
Castro, Pedro Machado Manhaes de
2012-08-01
Recently, it has been shown that, for Lambert illumination model, solely scenes composed by developable objects with a very particular albedo distribution produce an (2D) image with isolines that are (almost) invariant to light direction change. In this work, we provide and investigate a more general framework, and we show that, in general, the requirement for such in variances is quite strong, and is related to the differential geometry of the objects. More precisely, it is proved that single curved manifolds, i.e., manifolds such that at each point there is at most one principal curvature direction, produce invariant is surfaces for a certain relevant family of energy functions. In the three-dimensional case, the associated energy function corresponds to the classical Lambert illumination model with albedo. This result is also extended for finite-dimensional scenes composed by single curved objects. © 2012 IEEE.
A curved resonant flexoelectric actuator
Zhang, Shuwen; Liu, Kaiyuan; Xu, Minglong; Shen, Shengping
2017-08-01
Flexoelectricity is an electro-mechanical coupling effect that exists in all dielectrics and has the potential to replace piezoelectric actuating on the microscale. In this letter, a curved flexoelectric actuator with non-polarized polyvinylidene fluoride is presented and shown to exhibit good electro-mechanical properties. This provides experimental support for a body of theoretical research into converse flexoelectricity in polymeric materials. In addition, this work demonstrates the feasibility of lead-free microscale actuating without piezoelectricity.
Active Particles on Curved Surfaces
Fily, Yaouen; Baskaran, Aparna; Hagan, Michael F.
2016-01-01
Recent studies have highlighted the sensitivity of active matter to boundaries and their geometries. Here we develop a general theory for the dynamics and statistics of active particles on curved surfaces and illustrate it on two examples. We first show that active particles moving on a surface with no ability to probe its curvature only exhibit steady-state inhomogeneities in the presence of orientational order. We then consider a strongly confined 3D ideal active gas and compute its steady-...
Analyzing Exoplanet Phase Curve Information Content: Toward Optimized Observing Strategies
Placek, Ben; Angerhausen, Daniel; Knuth, Kevin H.
2017-10-01
Secondary eclipses and phase curves reveal information about the reflectivity and heat distribution in exoplanet atmospheres. The phase curve is composed of a combination of reflected and thermally emitted light from the planet, and for circular orbits the phase curve peaks during the secondary eclipse or at an orbital phase of 0.5. Physical mechanisms have been discovered that shift the phase curve maximum of tidally locked close-in planets to the right, or left, of the secondary eclipse. These mechanisms include cloud formations and atmospheric superrotation, both of which serve to shift the thermally bright hot-spot or highly reflective bright spot of the atmosphere away from the sub-stellar point. Here, we present a methodology for optimizing observing strategies for both secondary eclipses and phase curves with the goal of maximizing the information gained about the planetary atmosphere while minimizing the (assumed) continuous observation time. We show that we can increase the duty cycle of observations aimed at the measurements of phase curve characteristics (amplitude, phase offset) by up to 50% for future platforms such as CHaracterising ExOPlanets Satellite (CHEOPS) and JWST. We apply this methodology to the test cases of the Spitzer phase curve of 55-Cancri-e, which displays an eastward shift in its phase curve maximum as well as model-generated observations of an ultra-short period planet observed with CHEOPS.
Growth curves for Laron syndrome.
Laron, Z; Lilos, P; Klinger, B
1993-06-01
Growth curves for children with Laron syndrome were constructed on the basis of repeated measurements made throughout infancy, childhood, and puberty in 24 (10 boys, 14 girls) of the 41 patients with this syndrome investigated in our clinic. Growth retardation was already noted at birth, the birth length ranging from 42 to 46 cm in the 12/20 available measurements. The postnatal growth curves deviated sharply from the normal from infancy on. Both sexes showed no clear pubertal spurt. Girls completed their growth between the age of 16-19 years to a final mean (SD) height of 119 (8.5) cm whereas the boys continued growing beyond the age of 20 years, achieving a final height of 124 (8.5) cm. At all ages the upper to lower body segment ratio was more than 2 SD above the normal mean. These growth curves constitute a model not only for primary, hereditary insulin-like growth factor-I (IGF-I) deficiency (Laron syndrome) but also for untreated secondary IGF-I deficiencies such as growth hormone gene deletion and idiopathic congenital isolated growth hormone deficiency. They should also be useful in the follow up of children with Laron syndrome treated with biosynthetic recombinant IGF-I.
Projection-based curve clustering
International Nuclear Information System (INIS)
Auder, Benjamin; Fischer, Aurelie
2012-01-01
This paper focuses on unsupervised curve classification in the context of nuclear industry. At the Commissariat a l'Energie Atomique (CEA), Cadarache (France), the thermal-hydraulic computer code CATHARE is used to study the reliability of reactor vessels. The code inputs are physical parameters and the outputs are time evolution curves of a few other physical quantities. As the CATHARE code is quite complex and CPU time-consuming, it has to be approximated by a regression model. This regression process involves a clustering step. In the present paper, the CATHARE output curves are clustered using a k-means scheme, with a projection onto a lower dimensional space. We study the properties of the empirically optimal cluster centres found by the clustering method based on projections, compared with the 'true' ones. The choice of the projection basis is discussed, and an algorithm is implemented to select the best projection basis among a library of orthonormal bases. The approach is illustrated on a simulated example and then applied to the industrial problem. (authors)
2016-10-01
DISTRIBUTION STATEMENT: Approved for Public Release; Distribution Unlimited The views, opinions and/or findings contained in this report are those of the...overall survival. (G) Kaplan-Meier survival curve showing the significant delay of mortality caused by Pep-H6 peptibody treatment of Ptenpc-/-Smad4pc...purchased from US Biomax Tissue Microarray) for YAP1. Interestingly, YAP1 is expressed in basal cells, but not in the luminal cells of the normal
Dual Smarandache Curves and Smarandache Ruled Surfaces
Tanju KAHRAMAN; Mehmet ÖNDER; H. Hüseyin UGURLU
2013-01-01
In this paper, by considering dual geodesic trihedron (dual Darboux frame) we define dual Smarandache curves lying fully on dual unit sphere S^2 and corresponding to ruled surfaces. We obtain the relationships between the elements of curvature of dual spherical curve (ruled surface) x(s) and its dual Smarandache curve (Smarandache ruled surface) x1(s) and we give an example for dual Smarandache curves of a dual spherical curve.
Parametrizations of elliptic curves by Shimura curves and by classical modular curves.
Ribet, K A; Takahashi, S
1997-10-14
Fix an isogeny class of semistable elliptic curves over Q. The elements A of have a common conductor N, which is a square-free positive integer. Let D be a divisor of N which is the product of an even number of primes--i.e., the discriminant of an indefinite quaternion algebra over Q. To D we associate a certain Shimura curve X(0)D(N/D), whose Jacobian is isogenous to an abelian subvariety of J0(N). There is a unique A [symbol; see text] A in for which one has a nonconstant map piD : X(0)D(N/D) --> A whose pullback A --> Pic0(X(0)D(N/D)) is injective. The degree of piD is an integer deltaD which depends only on D (and the fixed isogeny class A). We investigate the behavior of deltaD as D varies.
J-holomorphic curves and symplectic topology
McDuff, Dusa
2012-01-01
The theory of J-holomorphic curves has been of great importance since its introduction by Gromov in 1985. In mathematics, its applications include many key results in symplectic topology. It was also one of the main inspirations for the creation of Floer homology. In mathematical physics, it provides a natural context in which to define Gromov-Witten invariants and quantum cohomology, two important ingredients of the mirror symmetry conjecture. The main goal of this book is to establish the fundamental theorems of the subject in full and rigorous detail. In particular, the book contains comple
Curves and tables of neutron cross sections
International Nuclear Information System (INIS)
Nakagawa, Tsuneo; Asami, Tetsuo; Yoshida, Tadashi
1990-07-01
Neutron cross-section curves from the Japanese Evaluated Nuclear Data Library version 3, JENDL-3, are presented in both graphical and tabular form for users in a wide range of application areas in the nuclear energy field. The contents cover cross sections for all the main reactions induced by neutrons with an energy below 20 MeV including; total, elastic scattering, capture, and fission, (n,n'), (n,2n), (n,3n), (n,α), (n,p) reactions. The 2200 m/s cross-section values, resonance integrals, and Maxwellian- and fission-spectrum averaged cross sections are also tabulated. (author)
Quaternion wave equations in curved space-time
Edmonds, J. D., Jr.
1974-01-01
The quaternion formulation of relativistic quantum theory is extended to include curvilinear coordinates and curved space-time in order to provide a framework for a unified quantum/gravity theory. Six basic quaternion fields are identified in curved space-time, the four-vector basis quaternions are identified, and the necessary covariant derivatives are obtained. Invariant field equations are derived, and a general invertable coordinate transformation is developed. The results yield a way of writing quaternion wave equations in curvilinear coordinates and curved space-time as well as a natural framework for solving the problem of second quantization for gravity.
Evolution of dust extinction curves in galaxy simulation
Hou, Kuan-Chou; Hirashita, Hiroyuki; Nagamine, Kentaro; Aoyama, Shohei; Shimizu, Ikkoh
2017-07-01
To understand the evolution of extinction curve, we calculate the dust evolution in a galaxy using smoothed particle hydrodynamic simulations incorporating stellar dust production, dust destruction in supernova shocks, grain growth by accretion and coagulation, and grain disruption by shattering. The dust species are separated into carbonaceous dust and silicate. The evolution of grain size distribution is considered by dividing grain population into large and small grains, which allows us to estimate extinction curves. We examine the dependence of extinction curves on the position, gas density and metallicity in the galaxy, and find that extinction curves are flat at t ≲ 0.3 Gyr because stellar dust production dominates the total dust abundance. The 2175 Å bump and far-ultraviolet (FUV) rise become prominent after dust growth by accretion. At t ≳ 3 Gyr, shattering works efficiently in the outer disc and low-density regions, so extinction curves show a very strong 2175 Å bump and steep FUV rise. The extinction curves at t ≳ 3 Gyr are consistent with the Milky Way extinction curve, which implies that we successfully included the necessary dust processes in the model. The outer disc component caused by stellar feedback has an extinction curve with a weaker 2175 Å bump and flatter FUV slope. The strong contribution of carbonaceous dust tends to underproduce the FUV rise in the Small Magellanic Cloud extinction curve, which supports selective loss of small carbonaceous dust in the galaxy. The snapshot at young ages also explains the extinction curves in high-redshift quasars.
A note on families of fragility curves
International Nuclear Information System (INIS)
Kaplan, S.; Bier, V.M.; Bley, D.C.
1989-01-01
In the quantitative assessment of seismic risk, uncertainty in the fragility of a structural component is usually expressed by putting forth a family of fragility curves, with probability serving as the parameter of the family. Commonly, a lognormal shape is used both for the individual curves and for the expression of uncertainty over the family. A so-called composite single curve can also be drawn and used for purposes of approximation. This composite curve is often regarded as equivalent to the mean curve of the family. The equality seems intuitively reasonable, but according to the authors has never been proven. The paper presented proves this equivalence hypothesis mathematically. Moreover, the authors show that this equivalence hypothesis between fragility curves is itself equivalent to an identity property of the standard normal probability curve. Thus, in the course of proving the fragility curve hypothesis, the authors have also proved a rather obscure, but interesting and perhaps previously unrecognized, property of the standard normal curve
NLINEAR - NONLINEAR CURVE FITTING PROGRAM
Everhart, J. L.
1994-01-01
A common method for fitting data is a least-squares fit. In the least-squares method, a user-specified fitting function is utilized in such a way as to minimize the sum of the squares of distances between the data points and the fitting curve. The Nonlinear Curve Fitting Program, NLINEAR, is an interactive curve fitting routine based on a description of the quadratic expansion of the chi-squared statistic. NLINEAR utilizes a nonlinear optimization algorithm that calculates the best statistically weighted values of the parameters of the fitting function and the chi-square that is to be minimized. The inputs to the program are the mathematical form of the fitting function and the initial values of the parameters to be estimated. This approach provides the user with statistical information such as goodness of fit and estimated values of parameters that produce the highest degree of correlation between the experimental data and the mathematical model. In the mathematical formulation of the algorithm, the Taylor expansion of chi-square is first introduced, and justification for retaining only the first term are presented. From the expansion, a set of n simultaneous linear equations are derived, which are solved by matrix algebra. To achieve convergence, the algorithm requires meaningful initial estimates for the parameters of the fitting function. NLINEAR is written in Fortran 77 for execution on a CDC Cyber 750 under NOS 2.3. It has a central memory requirement of 5K 60 bit words. Optionally, graphical output of the fitting function can be plotted. Tektronix PLOT-10 routines are required for graphics. NLINEAR was developed in 1987.
LINS Curve in Romanian Economy
Directory of Open Access Journals (Sweden)
Emilian Dobrescu
2016-02-01
Full Text Available The paper presents theoretical considerations and empirical evidence to test the validity of the Laffer in Narrower Sense (LINS curve as a parabola with a maximum. Attention is focused on the so-called legal-effective tax gap (letg. The econometric application is based on statistical data (1990-2013 for Romania as an emerging European economy. Three cointegrating regressions (fully modified least squares, canonical cointegrating regression and dynamic least squares and three algorithms, which are based on instrumental variables (two-stage least squares, generalized method of moments, and limited information maximum likelihood, are involved.
Principal Curves on Riemannian Manifolds
DEFF Research Database (Denmark)
Hauberg, Søren
2015-01-01
Euclidean statistics are often generalized to Riemannian manifolds by replacing straight-line interpolations with geodesic ones. While these Riemannian models are familiar-looking, they are restricted by the inflexibility of geodesics, and they rely on constructions which are optimal only...... in Euclidean domains. We consider extensions of Principal Component Analysis (PCA) to Riemannian manifolds. Classic Riemannian approaches seek a geodesic curve passing through the mean that optimize a criteria of interest. The requirements that the solution both is geodesic and must pass through the mean tend...
Lightlike contractions in curved spacetime
International Nuclear Information System (INIS)
Aichelburg, P.C.; Embacher, F.
1984-01-01
The technique of lightlike contractions in flat and curved space is described. The method consists in boosting a classical field configuration to the velocity of light by an appropriate generalized Lorentz transformation. Within this framework the gravitational field of a massless neutral particle is a meaningful concept. For electrically charged particles, however, the field equations seem to prevent an analogous procedure. We thus conjecture that general relativity forbids the existance of charged point particles moving with the velocity of light. Further examples for lightlike contractions of a self-dual electromagnetic field and of a linearized Rarita-Schwinger (spin-3/2) field are given. (Author)
Flow characteristics of curved ducts
Directory of Open Access Journals (Sweden)
Rudolf P.
2007-10-01
Full Text Available Curved channels are very often present in real hydraulic systems, e.g. curved diffusers of hydraulic turbines, S-shaped bulb turbines, fittings, etc. Curvature brings change of velocity profile, generation of vortices and production of hydraulic losses. Flow simulation using CFD techniques were performed to understand these phenomena. Cases ranging from single elbow to coupled elbows in shapes of U, S and spatial right angle position with circular cross-section were modeled for Re = 60000. Spatial development of the flow was studied and consequently it was deduced that minor losses are connected with the transformation of pressure energy into kinetic energy and vice versa. This transformation is a dissipative process and is reflected in the amount of the energy irreversibly lost. Least loss coefficient is connected with flow in U-shape elbows, biggest one with flow in Sshape elbows. Finally, the extent of the flow domain influenced by presence of curvature was examined. This isimportant for proper placement of mano- and flowmeters during experimental tests. Simulations were verified with experimental results presented in literature.
Classical optics and curved spaces
International Nuclear Information System (INIS)
Bailyn, M.; Ragusa, S.
1976-01-01
In the eikonal approximation of classical optics, the unit polarization 3-vector of light satisfies an equation that depends only on the index, n, of refraction. It is known that if the original 3-space line element is d sigma 2 , then this polarization direction propagates parallely in the fictitious space n 2 d sigma 2 . Since the equation depends only on n, it is possible to invent a fictitious curved 4-space in which the light performs a null geodesic, and the polarization 3-vector behaves as the 'shadow' of a parallely propagated 4-vector. The inverse, namely, the reduction of Maxwell's equation, on a curve 'dielectric free) space, to a classical space with dielectric constant n=(-g 00 ) -1 / 2 is well known, but in the latter the dielectric constant epsilon and permeability μ must also equal (-g 00 ) -1 / 2 . The rotation of polarization as light bends around the sun by utilizing the reduction to the classical space, is calculated. This (non-) rotation may then be interpreted as parallel transport in the 3-space n 2 d sigma 2 [pt
Deformation Based Curved Shape Representation.
Demisse, Girum G; Aouada, Djamila; Ottersten, Bjorn
2017-06-02
In this paper, we introduce a deformation based representation space for curved shapes in Rn. Given an ordered set of points sampled from a curved shape, the proposed method represents the set as an element of a finite dimensional matrix Lie group. Variation due to scale and location are filtered in a preprocessing stage, while shapes that vary only in rotation are identified by an equivalence relationship. The use of a finite dimensional matrix Lie group leads to a similarity metric with an explicit geodesic solution. Subsequently, we discuss some of the properties of the metric and its relationship with a deformation by least action. Furthermore, invariance to reparametrization or estimation of point correspondence between shapes is formulated as an estimation of sampling function. Thereafter, two possible approaches are presented to solve the point correspondence estimation problem. Finally, we propose an adaptation of k-means clustering for shape analysis in the proposed representation space. Experimental results show that the proposed representation is robust to uninformative cues, e.g. local shape perturbation and displacement. In comparison to state of the art methods, it achieves a high precision on the Swedish and the Flavia leaf datasets and a comparable result on MPEG-7, Kimia99 and Kimia216 datasets.
European column buckling curves and finite element modelling including high strength steels
DEFF Research Database (Denmark)
Jönsson, Jeppe; Stan, Tudor-Cristian
2017-01-01
deterministic analysis can be performed based on given magnitudes of characteristic yield stress, material stress–strain relationship, and given characteristic values for imperfections and residual stresses. The magnitude of imperfections and residual stresses are discussed as well as how the use of equivalent...
Probabilistic assessment of fatigue life including statistical uncertainties in the S-N curve
International Nuclear Information System (INIS)
Sudret, B.; Hornet, P.; Stephan, J.-M.; Guede, Z.; Lemaire, M.
2003-01-01
A probabilistic framework is set up to assess the fatigue life of components of nuclear power plants. It intends to incorporate all kinds of uncertainties such as those appearing in the specimen fatigue life, design sub-factor, mechanical model and applied loading. This paper details the first step, which corresponds to the statistical treatment of the fatigue specimen test data. The specimen fatigue life at stress amplitude S is represented by a lognormal random variable whose mean and standard deviation depend on S. This characterization is then used to compute the random fatigue life of a component submitted to a single kind of cycles. Precisely the mean and coefficient of variation of this quantity are studied, as well as the reliability associated with the (deterministic) design value. (author)
Smarandache Curves In Terms of Sabban Frame of Fixed Pole Curve
Directory of Open Access Journals (Sweden)
Süleyman Şenyurt
2016-06-01
Full Text Available In this paper, we study the special Smarandache curve interms of Sabban frame of Fixed Pole curve and we give some characterization of Smarandache curves. Besides, we illustrate examples of our results.
A Comparative Study of Learning Curve Models in Defense Airframe Cost Estimating
2015-03-26
modern forgetting curve methodology including the models that attempt to relate the two together. The theory and methodology will be followed by a...Forgetting and Forgetting Curve Models Learning and unlearning often take place simultaneously in manufacturing and production environments. Learning...concept to measure the impact of forgetting on overall performance. Jaber and Sikstrom (2004) identify the potential for forgetting curve research
Integrable System and Motion of Curves in Projective and Similarity Geometries
International Nuclear Information System (INIS)
Hou Yuqing
2006-01-01
Based on the natural frame in the projective geometry, motions of curves in projective geometry are studied. It is shown that several integrable equations including Sawada-Kotera and KK equations arise from motion of plane curves in projective geometries. Motion of space curves described by acceleration field and governed by endowing an extra space variable in similarity geometry P 3 is also studied.
Strong laws for generalized absolute Lorenz curves when data are stationary and ergodic sequences
R. Helmers (Roelof); R. Zitikis
2004-01-01
textabstractWe consider generalized absolute Lorenz curves that include, as special cases, classical and generalized L - statistics as well as absolute or, in other words, generalized Lorenz curves. The curves are based on strictly stationary and ergodic sequences of random variables. Most of the
Energy Technology Data Exchange (ETDEWEB)
Salavati, Ali [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); University of Minnesota, Department of Radiology, Minneapolis, MN (United States); Duan, Fenghai [Brown University School of Public Health, Department of Biostatistics and Center for Statistical Sciences, Providence, RI (United States); Snyder, Bradley S. [Brown University School of Public Health, Center for Statistical Sciences, Providence, RI (United States); Wei, Bo [Emory University, Department of Biostatistics, Rollins School of Public Health, Atlanta, GA (United States); Houshmand, Sina; Alavi, Abass [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Khiewvan, Benjapa [Hospital of the University of Pennsylvania, Department of Radiology, Philadelphia, PA (United States); Mahidol University, Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine Siriraj Hospital, Bangkok (Thailand); Opanowski, Adam [ACR Center for Research and Innovation, American College of Radiology, Philadelphia, PA (United States); Simone, Charles B. [University of Maryland Medical Center, Department of Radiation Oncology, Baltimore, MD (United States); Siegel, Barry A. [Washington University School of Medicine, Mallinckrodt Institute of Radiology and the Alvin J. Siteman Cancer Center, St, Louis, MO (United States); Machtay, Mitchell [Case Western Reserve University and University Hospitals Case Medical Center, Department of Radiation Oncology, Cleveland, OH (United States)
2017-11-15
In recent years, multiple studies have demonstrated the value of volumetric FDG-PET/CT parameters as independent prognostic factors in patients with non-small cell lung cancer (NSCLC). We aimed to determine the optimal cut-off points of pretreatment volumetric FDG-PET/CT parameters in predicting overall survival (OS) in patients with locally advanced NSCLC and to recommend imaging biomarkers appropriate for routine clinical applications. Patients with inoperable stage IIB/III NSCLC enrolled in ACRIN 6668/RTOG 0235 were included. Pretreatment FDG-PET scans were quantified using semiautomatic adaptive contrast-oriented thresholding and local-background partial-volume-effect-correction algorithms. For each patient, the following indices were measured: metabolic tumor volume (MTV), total lesion glycolysis (TLG), SUVmax, SUVmean, partial-volume-corrected TLG (pvcTLG), and pvcSUVmean for the whole-body, primary tumor, and regional lymph nodes. The association between each index and patient outcome was assessed using Cox proportional hazards regression. Optimal cut-off points were estimated using recursive binary partitioning in a conditional inference framework and used in Kaplan-Meier curves with log-rank testing. The discriminatory ability of each index was examined using time-dependent receiver operating characteristic (ROC) curves and corresponding area under the curve (AUC(t)). The study included 196 patients. Pretreatment whole-body and primary tumor MTV, TLG, and pvcTLG were independently prognostic of OS. Optimal cut-off points were 175.0, 270.9, and 35.5 cm{sup 3} for whole-body TLG, pvcTLG, and MTV, and were 168.2, 239.8, and 17.4 cm{sup 3} for primary tumor TLG, pvcTLG, and MTV, respectively. In time-dependent ROC analysis, AUC(t) for MTV and TLG were uniformly higher than that of SUV measures over all time points. Primary tumor and whole-body parameters demonstrated similar patterns of separation for those patients above versus below the optimal cut
Transition curves for highway geometric design
Kobryń, Andrzej
2017-01-01
This book provides concise descriptions of the various solutions of transition curves, which can be used in geometric design of roads and highways. It presents mathematical methods and curvature functions for defining transition curves. .
Integration over Tropical Plane Curves and Ultradiscretization
Iwao, Shinsuke
2008-01-01
In this article we study holomorphic integrals on tropical plane curves in view of ultradiscretization. We prove that the lattice integrals over tropical curves can be obtained as a certain limit of complex integrals over Riemannian surfaces.
Estimation method of the fracture resistance curve
Energy Technology Data Exchange (ETDEWEB)
Cho, Sung Keun; Lee, Kwang Hyeon; Koo, Jae Mean; Seok, Chang Sung [Sungkyunkwan Univ., Suwon (Korea, Republic of); Park, Jae Sil [Samsung Electric Company, Suwon (Korea, Republic of)
2008-07-01
Fracture resistance curves for concerned materials are required in order to perform elastic-plastic fracture mechanical analysis. Fracture resistance curve is built with J-integral values and crack extension values. The objective of this paper is to propose the estimation method of the fracture resistance curve. The estimation method of the fracture resistance curve for the pipe specimen was proposed by the load ratio method from load - displacement data for the standard specimen.
M-curves and symmetric products
Indian Academy of Sciences (India)
Indranil Biswas
2017-08-03
Aug 3, 2017 ... Since M-curves play a special role in the topology of real algebraic varieties, it is useful to have a criterion for M-curves. It was proved earlier that a curve defined over R is an. M-curve if and only if its Jacobian is an M-variety [5]. We use this result of [5] and the. Picard bundle to prove that the n-th symmetric ...
Modeling fertility curves in Africa
Directory of Open Access Journals (Sweden)
Ezra Gayawan
2010-02-01
Full Text Available The modeling of fertility patterns is an essential method researchers use to understand world-wide population patterns. Various types of fertility models have been reported in the literature to capture the patterns specific to developed countries. While much effort has been put into reducing fertility rates in Africa, models which describe the fertility patterns have not been adequately described. This article presents a flexible parametric model that can adequately capture the varying patterns of the age-specific fertility curves of African countries. The model has parameters that are interpretable in terms of demographic indices. The performance of this model was compared with other commonly used models and Akaike's Information Criterion was used for selecting the model with best fit. The presented model was able to reproduce the empirical fertility data of 11 out of 15 countries better than the other models considered.
Ait-Haddou, Rachid
2013-02-01
We show that the generalized Bernstein bases in Müntz spaces defined by Hirschman and Widder (1949) and extended by Gelfond (1950) can be obtained as pointwise limits of the Chebyshev–Bernstein bases in Müntz spaces with respect to an interval [a,1][a,1] as the positive real number a converges to zero. Such a realization allows for concepts of curve design such as de Casteljau algorithm, blossom, dimension elevation to be transferred from the general theory of Chebyshev blossoms in Müntz spaces to these generalized Bernstein bases that we termed here as Gelfond–Bernstein bases. The advantage of working with Gelfond–Bernstein bases lies in the simplicity of the obtained concepts and algorithms as compared to their Chebyshev–Bernstein bases counterparts.
Euler characteristics and elliptic curves.
Coates, J; Howson, S
1997-10-14
Let E be a modular elliptic curve over [symbol, see text], without complex multiplication; let p be a prime number where E has good ordinary reduction; and let Finfinity be the field obtained by adjoining [symbol, see text] to all p-power division points on E. Write Ginfinity for the Galois group of Finfinity over [symbol, see text]. Assume that the complex L-series of E over [symbol, see text] does not vanish at s = 1. If p >/= 5, we make a precise conjecture about the value of the Ginfinity-Euler characteristic of the Selmer group of E over Finfinity. If one makes a standard conjecture about the behavior of this Selmer group as a module over the Iwasawa algebra, we are able to prove our conjecture. The crucial local calculations in the proof depend on recent joint work of the first author with R. Greenberg.
Bacterial streamers in curved microchannels
Rusconi, Roberto; Lecuyer, Sigolene; Guglielmini, Laura; Stone, Howard
2009-11-01
Biofilms, generally identified as microbial communities embedded in a self-produced matrix of extracellular polymeric substances, are involved in a wide variety of health-related problems ranging from implant-associated infections to disease transmissions and dental plaque. The usual picture of these bacterial films is that they grow and develop on surfaces. However, suspended biofilm structures, or streamers, have been found in natural environments (e.g., rivers, acid mines, hydrothermal hot springs) and are always suggested to stem from a turbulent flow. We report the formation of bacterial streamers in curved microfluidic channels. By using confocal laser microscopy we are able to directly image and characterize the spatial and temporal evolution of these filamentous structures. Such streamers, which always connect the inner corners of opposite sides of the channel, are always located in the middle plane. Numerical simulations of the flow provide evidences for an underlying hydrodynamic mechanism behind the formation of the streamers.
AKLSQF - LEAST SQUARES CURVE FITTING
Kantak, A. V.
1994-01-01
The Least Squares Curve Fitting program, AKLSQF, computes the polynomial which will least square fit uniformly spaced data easily and efficiently. The program allows the user to specify the tolerable least squares error in the fitting or allows the user to specify the polynomial degree. In both cases AKLSQF returns the polynomial and the actual least squares fit error incurred in the operation. The data may be supplied to the routine either by direct keyboard entry or via a file. AKLSQF produces the least squares polynomial in two steps. First, the data points are least squares fitted using the orthogonal factorial polynomials. The result is then reduced to a regular polynomial using Sterling numbers of the first kind. If an error tolerance is specified, the program starts with a polynomial of degree 1 and computes the least squares fit error. The degree of the polynomial used for fitting is then increased successively until the error criterion specified by the user is met. At every step the polynomial as well as the least squares fitting error is printed to the screen. In general, the program can produce a curve fitting up to a 100 degree polynomial. All computations in the program are carried out under Double Precision format for real numbers and under long integer format for integers to provide the maximum accuracy possible. AKLSQF was written for an IBM PC X/AT or compatible using Microsoft's Quick Basic compiler. It has been implemented under DOS 3.2.1 using 23K of RAM. AKLSQF was developed in 1989.
Sibling curves of quadratic polynomials | Wiggins | Quaestiones ...
African Journals Online (AJOL)
Sibling curves were demonstrated in [1, 2] as a novel way to visualize the zeroes of real valued functions. In [3] it was shown that a polynomial of degree n has n sibling curves. This paper focuses on the algebraic and geometric properites of the sibling curves of real and complex quadratic polynomials. Key words: Quadratic ...
Legendre Elliptic Curves over Finite Fields
Auer, Roland; Top, Jakob
2002-01-01
We show that every elliptic curve over a finite field of odd characteristic whose number of rational points is divisible by 4 is isogenous to an elliptic curve in Legendre form, with the sole exception of a minimal respectively maximal elliptic curve. We also collect some results concerning the
Trigonometric Characterization of Some Plane Curves
Indian Academy of Sciences (India)
IAS Admin
(Figure 1). A relation between tan θ and tanψ gives the trigonometric equation of the family of curves. In this article, trigonometric equations of some known plane curves are deduced and it is shown that these equations reveal some geometric characteristics of the families of the curves under consideration. In Section 2,.
Holomorphic curves in exploded manifolds: Kuranishi structure
Parker, Brett
2013-01-01
This paper constructs a Kuranishi structure for the moduli stack of holomorphic curves in exploded manifolds. To avoid some technicalities of abstract Kuranishi structures, we embed our Kuranishi structure inside a moduli stack of curves. The construction also works for the moduli stack of holomorphic curves in any compact symplectic manifold.
Automated Blazar Light Curves Using Machine Learning
Energy Technology Data Exchange (ETDEWEB)
Johnson, Spencer James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-07-27
This presentation describes a problem and methodology pertaining to automated blazar light curves. Namely, optical variability patterns for blazars require the construction of light curves and in order to generate the light curves, data must be filtered before processing to ensure quality.
Pump apparatus including deconsolidator
Energy Technology Data Exchange (ETDEWEB)
Sonwane, Chandrashekhar; Saunders, Timothy; Fitzsimmons, Mark Andrew
2014-10-07
A pump apparatus includes a particulate pump that defines a passage that extends from an inlet to an outlet. A duct is in flow communication with the outlet. The duct includes a deconsolidator configured to fragment particle agglomerates received from the passage.
Reactor Pressure Vessel P-T Limit Curve Round Robin
Energy Technology Data Exchange (ETDEWEB)
Jang, C.H.; Moon, H.R.; Jeong, I.S. [Korea Electric Power Research Institute, Taejon (Korea)
2002-07-01
This report is the summary of the analysis results for the P-T Limit Curve construction which have been subjected to the round robin analysis. The purpose of the round robin is to compare the procedure and method used in various organizations to construct P-T limit curve to prevent brittle fracture of reactor pressure vessel of nuclear power plants. Each Participant used its own approach to construct the P-T limit curve and submitted the results, By analyzing the results, the reference procedure for the P-T limit curve could be established. This report include the results of the comparison of the procedure and method used by the participants, and sensitivity study of the key parameters. (author) 23 refs, 88 figs, 17 tabs.
Path Integrals and Anomalies in Curved Space
Energy Technology Data Exchange (ETDEWEB)
Louko, Jorma [University of Nottingham (United Kingdom)
2007-04-07
Bastianelli and van Nieuwenhuizen's monograph 'Path Integrals and Anomalies in Curved Space' collects in one volume the results of the authors' 15-year research programme on anomalies that arise in Feynman diagrams of quantum field theories on curved manifolds. The programme was spurred by the path-integral techniques introduced in Alvarez-Gaume and Witten's renowned 1983 paper on gravitational anomalies which, together with the anomaly cancellation paper by Green and Schwarz, led to the string theory explosion of the 1980s. The authors have produced a tour de force, giving a comprehensive and pedagogical exposition of material that is central to current research. The first part of the book develops from scratch a formalism for defining and evaluating quantum mechanical path integrals in nonlinear sigma models, using time slicing regularization, mode regularization and dimensional regularization. The second part applies this formalism to quantum fields of spin 0, 1/2, 1 and 3/2 and to self-dual antisymmetric tensor fields. The book concludes with a discussion of gravitational anomalies in 10-dimensional supergravities, for both classical and exceptional gauge groups. The target audience is researchers and graduate students in curved spacetime quantum field theory and string theory, and the aims, style and pedagogical level have been chosen with this audience in mind. Path integrals are treated as calculational tools, and the notation and terminology are throughout tailored to calculational convenience, rather than to mathematical rigour. The style is closer to that of an exceedingly thorough and self-contained review article than to that of a textbook. As the authors mention, the first part of the book can be used as an introduction to path integrals in quantum mechanics, although in a classroom setting perhaps more likely as supplementary reading than a primary class text. Readers outside the core audience, including this reviewer, will
Method of construction spatial transition curve
Directory of Open Access Journals (Sweden)
S.V. Didanov
2013-04-01
Full Text Available Purpose. The movement of rail transport (speed rolling stock, traffic safety, etc. is largely dependent on the quality of the track. In this case, a special role is the transition curve, which ensures smooth insertion of the transition from linear to circular section of road. The article deals with modeling of spatial transition curve based on the parabolic distribution of the curvature and torsion. This is a continuation of research conducted by the authors regarding the spatial modeling of curved contours. Methodology. Construction of the spatial transition curve is numerical methods for solving nonlinear integral equations, where the initial data are taken coordinate the starting and ending points of the curve of the future, and the inclination of the tangent and the deviation of the curve from the tangent plane at these points. System solutions for the numerical method are the partial derivatives of the equations of the unknown parameters of the law of change of torsion and length of the transition curve. Findings. The parametric equations of the spatial transition curve are calculated by finding the unknown coefficients of the parabolic distribution of the curvature and torsion, as well as the spatial length of the transition curve. Originality. A method for constructing the spatial transition curve is devised, and based on this software geometric modeling spatial transition curves of railway track with specified deviations of the curve from the tangent plane. Practical value. The resulting curve can be applied in any sector of the economy, where it is necessary to ensure a smooth transition from linear to circular section of the curved space bypass. An example is the transition curve in the construction of the railway line, road, pipe, profile, flat section of the working blades of the turbine and compressor, the ship, plane, car, etc.
Optical modulator including grapene
Liu, Ming; Yin, Xiaobo; Zhang, Xiang
2016-06-07
The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.
Focal Conic Flower Textures at Curved Interfaces
Directory of Open Access Journals (Sweden)
Daniel A. Beller
2013-12-01
Full Text Available Focal conic domains (FCDs in smectic-A liquid crystals have drawn much attention, both for their exquisitely structured internal form and for their ability to direct the assembly of micromaterials and nanomaterials in a variety of patterns. A key to directing FCD assembly is control over the eccentricity of the domain. Here, we demonstrate a new paradigm for creating spatially varying FCD eccentricity by confining a hybrid-aligned smectic with curved interfaces. In particular, we manipulate interface behavior with colloidal particles in order to experimentally produce two examples of what has recently been dubbed the flower texture [C. Meyer et al., Focal Conic Stacking in Smectic A Liquid Crystals: Smectic Flower and Apollonius Tiling, Materials 2, 499, 2009MATEG91996-194410.3390/ma2020499], where the focal hyperbolæ diverge radially outward from the center of the texture, rather than inward as in the canonical éventail or fan texture. We explain how this unconventional assembly can arise from appropriately curved interfaces. Finally, we present a model for this system that applies the law of corresponding cones, showing how FCDs may be embedded smoothly within a “background texture” of large FCDs and concentric spherical layers, in a manner consistent with the qualitative features of the smectic flower. Such understanding could potentially lead to disruptive liquid-crystal technologies beyond displays, including patterning, smart surfaces, microlens arrays, sensors, and nanomanufacturing.
Modeling of alpha mass-efficiency curve
International Nuclear Information System (INIS)
Semkow, T.M.; Jeter, H.W.; Parsa, B.; Parekh, P.P.; Haines, D.K.; Bari, A.
2005-01-01
We present a model for efficiency of a detector counting gross α radioactivity from both thin and thick samples, corresponding to low and high sample masses in the counting planchette. The model includes self-absorption of α particles in the sample, energy loss in the absorber, range straggling, as well as detector edge effects. The surface roughness of the sample is treated in terms of fractal geometry. The model reveals a linear dependence of the detector efficiency on the sample mass, for low masses, as well as a power-law dependence for high masses. It is, therefore, named the linear-power-law (LPL) model. In addition, we consider an empirical power-law (EPL) curve, and an exponential (EXP) curve. A comparison is made of the LPL, EPL, and EXP fits to the experimental α mass-efficiency data from gas-proportional detectors for selected radionuclides: 238 U, 230 Th, 239 Pu, 241 Am, and 244 Cm. Based on this comparison, we recommend working equations for fitting mass-efficiency data. Measurement of α radioactivity from a thick sample can determine the fractal dimension of its surface
Power forward curves: a managerial perspective
International Nuclear Information System (INIS)
Nagarajan, Shankar
1999-01-01
This chapter concentrates on managerial application of power forward curves, and examines the determinants of electricity prices such as transmission constraints, its inability to be stored in a conventional way, its seasonality and weather dependence, the generation stack, and the swing risk. The electricity forward curve, classical arbitrage, constructing a forward curve, volatilities, and electricity forward curve models such as the jump-diffusion model, the mean-reverting heteroscedastic volatility model, and an econometric model of forward prices are examined. A managerial perspective of the applications of the forward curve is presented covering plant valuation, capital budgeting, performance measurement, product pricing and structuring, asset optimisation, valuation of transmission options, and risk management
Retrograde curves of solidus and solubility
International Nuclear Information System (INIS)
Vasil'ev, M.V.
1979-01-01
The investigation was concerned with the constitutional diagrams of the eutectic type with ''retrograde solidus'' and ''retrograde solubility curve'' which must be considered as diagrams with degenerate monotectic transformation. The solidus and the solubility curves form a retrograde curve with a common retrograde point representing the solubility maximum. The two branches of the Aetrograde curve can be described with the aid of two similar equations. Presented are corresponding equations for the Cd-Zn system and shown is the possibility of predicting the run of the solubility curve
Xu, Juan; Xu, Tian; Bu, Xiaoqing; Peng, Hao; Li, Hongmei; Zhang, Mingzhi; Zhang, Yonghong
2014-01-01
To explore the associations between waist-to-height ratio (WHtR), body mass index (BMI) and waist circumference (WC) and risk of ischemic stroke among Mongolian men in China. A population-based prospective cohort study was conducted from June 2003 to July 2012 in Inner Mongolia, an autonomous region in north China. A total of 1034 men aged 20 years and older free of cardiovascular disease were included in the cohort and followed up for an average of 9.2 years. The subjects were divided into four groups by WHtR levels (WHtR0.60). The cumulative survival rates of ischemic stroke among the four groups were estimated with the Kaplan-Meier curves and compared by log-rank test. Cox proportional hazards models and Receiver Operating Characteristic (ROC) curves were employed to evaluate the associations between obesity indices and ischemic stroke. A total of 47 ischemic stroke patients were observed during the follow-up period. The cumulative incidence and incidence density of ischemic stroke were 4.55% and 507.61/100 000 person-years, respectively. After the major risk factors were adjusted, individuals with WHtR>0.60 had a 3.56-fold increased risk of ischemic stroke compared with those with 0.40≤WHtR≤0.50. Hazard ratio (HR) and 95% confidence intervals (CI) of ischemic stroke for a 1-SD increase in WHtR was 1.34(95% CI: 1.00-1.81). After adding BMI or WC to models, higher WHtR remained significantly associated with increased risk of ischemic stroke. The Kaplan-Meier survival curves showed that the cumulative survival rate in the group with WHtR>0.60 was significantly lower than in the group with 0.40≤WHtR≤0.50 (log-rank test, P = 0.025). The areas under the curve for each index were as follows: 0.586 for WHtR, 0.543 for WC; 0.566 for BMI. Higher WHtR is associated with risk of ischemic stroke in Mongolian males. WHtR may be useful in predicting ischemic stroke incidence in males.
Gabauer, Douglas J; Li, Xiaolong
2015-04-01
The purpose of this study was to investigate motorcycle-to-barrier crash frequency on horizontally curved roadway sections in Washington State using police-reported crash data linked with roadway data and augmented with barrier presence information. Data included 4915 horizontal curved roadway sections with 252 of these sections experiencing 329 motorcycle-to-barrier crashes between 2002 and 2011. Negative binomial regression was used to predict motorcycle-to-barrier crash frequency using horizontal curvature and other roadway characteristics. Based on the model results, the strongest predictor of crash frequency was found to be curve radius. This supports a motorcycle-to-barrier crash countermeasure placement criterion based, at the very least, on horizontal curve radius. With respect to the existing horizontal curve criterion of 820 feet or less, curves meeting this criterion were found to increase motorcycle-to-barrier crash frequency rate by a factor of 10 compared to curves not meeting this criterion. Other statistically significant predictors were curve length, traffic volume and the location of adjacent curves. Assuming curves of identical radius, the model results suggest that longer curves, those with higher traffic volume, and those that have no adjacent curved sections within 300 feet of either curve end would likely be better candidates for a motorcycle-to-barrier crash countermeasure. Copyright © 2015 Elsevier Ltd. All rights reserved.
Alternative Gravity Rotation Curves for the LITTLE THINGS Survey
O’Brien, James G.; Chiarelli, Thomas L.; Dentico, Jeremy; Stulge, Modestas; Stefanski, Brian; Moss, Robert; Chaykov, Spasen
2018-01-01
Galactic rotation curves have proven to be the testing ground for dark matter bounds in spiral galaxies of all morphologies. Dwarf galaxies serve as an increasingly interesting case of rotation curve dynamics due to their typically rising rotation curve as opposed to the flattening curve of large spirals. Dwarf galaxies usually vary in galactic structure and mostly terminate at small radial distances. This, coupled with the fact that Cold Dark Matter theories struggle with the universality of galactic rotation curves, allow for exclusive features of alternative gravitational models to be analyzed. Recently, The H I Nearby Galactic Survey (THINGS) has been extended to include a sample of 25 dwarf galaxies now known as the LITTLE THINGS Survey. Here, we show an application of alternative gravitational models to the LITTLE THINGS survey, specifically focusing on conformal gravity (CG) and Modified Newtonian Dynamics (MOND). In this work, we provide an analysis and discussion of the rotation curve predictions of each theory to the sample. Furthermore, we show how these two alternative gravitational models account for the recently observed universal trends in centripetal accelerations in spiral galaxies. This work highlights the similarities and differences of the predictions of the two theories in dwarf galaxies. The sample is not large or diverse enough to strongly favor a single theory, but we posit that both CG and MOND can provide an accurate description of the galactic dynamics in the LITTLE THINGS sample without the need for dark matter.
Growth curves in Down syndrome with congenital heart disease
Directory of Open Access Journals (Sweden)
Caroline D’Azevedo Sica
Full Text Available SUMMARY Introduction: To assess dietary habits, nutritional status and food frequency in children and adolescents with Down syndrome (DS and congenital heart disease (CHD. Additionally, we attempted to compare body mass index (BMI classifications according to the World Health Organization (WHO curves and curves developed for individuals with DS. Method: Cross-sectional study including individuals with DS and CHD treated at a referral center for cardiology, aged 2 to 18 years. Weight, height, BMI, total energy and food frequency were measured. Nutritional status was assessed using BMI for age and gender, using curves for evaluation of patients with DS and those set by the WHO. Results: 68 subjects with DS and CHD were evaluated. Atrioventricular septal defect (AVSD was the most common heart disease (52.9%. There were differences in BMI classification between the curves proposed for patients with DS and those proposed by the WHO. There was an association between consumption of vitamin E and polyunsaturated fatty acids. Conclusion: Results showed that individuals with DS are mostly considered normal weight for age, when evaluated using specific curves for DS. Reviews on specific curves for DS would be the recommended practice for health professionals so as to avoid precipitated diagnosis of overweight and/or obesity in this population.
An appraisal of the learning curve in robotic general surgery.
Pernar, Luise I M; Robertson, Faith C; Tavakkoli, Ali; Sheu, Eric G; Brooks, David C; Smink, Douglas S
2017-11-01
Robotic-assisted surgery is used with increasing frequency in general surgery for a variety of applications. In spite of this increase in usage, the learning curve is not yet defined. This study reviews the literature on the learning curve in robotic general surgery to inform adopters of the technology. PubMed and EMBASE searches yielded 3690 abstracts published between July 1986 and March 2016. The abstracts were evaluated based on the following inclusion criteria: written in English, reporting original work, focus on general surgery operations, and with explicit statistical methods. Twenty-six full-length articles were included in final analysis. The articles described the learning curves in colorectal (9 articles, 35%), foregut/bariatric (8, 31%), biliary (5, 19%), and solid organ (4, 15%) surgery. Eighteen of 26 (69%) articles report single-surgeon experiences. Time was used as a measure of the learning curve in all studies (100%); outcomes were examined in 10 (38%). In 12 studies (46%), the authors identified three phases of the learning curve. Numbers of cases needed to achieve plateau performance were wide-ranging but overlapping for different kinds of operations: 19-128 cases for colorectal, 8-95 for foregut/bariatric, 20-48 for biliary, and 10-80 for solid organ surgery. Although robotic surgery is increasingly utilized in general surgery, the literature provides few guidelines on the learning curve for adoption. In this heterogeneous sample of reviewed articles, the number of cases needed to achieve plateau performance varies by case type and the learning curve may have multiple phases as surgeons add more complex cases to their case mix with growing experience. Time is the most common determinant for the learning curve. The literature lacks a uniform assessment of outcomes and complications, which would arguably reflect expertise in a more meaningful way than time to perform the operation alone.
Talking Curves at the Montreaux+5 Conference
DEFF Research Database (Denmark)
Leander, Anna
This tale is drawn from fieldwork I did at the Montreux+5 Conference in (yes!) Montreux, 11-13 December 2013. The conference was organized by those who initiated, sponsored and promoted the Montreux Document on Pertinent International Legal Obligations and Good Practices for States related...... in armed conflicts”. To this end the MD spells out “pertinent legal obligations” (on four pages and a small paragraph) but also “best practices” (on eleven full pages). The Montreux+5 Conference celebrated the document’s fifth anniversary. The party was held to review the MD but also to promote it. Invited...... were the signatory states, non-signatory states, but also assorted companies, NGOs and academics (including myself) susceptible of having a view on the topic. I want to tell the political tale of how talking in curves around the MD at the Montreux+5 “translated” security in plural, non...
Analytical extension of curved shock theory
Emanuel, G.
2018-03-01
Curved shock theory (CST) is limited to shock waves in a steady, two-dimensional or axisymmetric (2-Ax) flow of a perfect gas. A unique feature of CST is its use of intrinsic coordinates that result in an elegant and useful formulation for flow properties just downstream of a shock. For instance, the downstream effect of upstream vorticity, shock wave curvature, and the upstream pressure gradient along a streamline is established. There have been several attempts to extend CST, as mentioned in the text. Removal of the steady, 2-Ax, and perfect gas limitations, singly or in combination, requires an appropriate formulation of the shock wave's jump relations and the intrinsic coordinate Euler equations. Issues discussed include flow plane versus osculating plane, unsteady flow, vorticity, an imperfect gas, etc. The extension of CST utilizes concepts from differential geometry, such as the osculating plane, streamline torsion, and the Serret-Frenet equations.
Dual effects of phytoestrogens result in u-shaped dose-response curves
DEFF Research Database (Denmark)
Almstrup, Kristian; Fernández, Mariana F; Petersen, Jørgen H
2002-01-01
, including synthetic chemicals and phytoestrogens, for aromatase inhibition. The phytoestrogens, except genistein, were aromatase inhibitors at low concentrations (resulting in U-shaped dose-response curves. None...
Localized qubits in curved spacetimes
Palmer, Matthew C.; Takahashi, Maki; Westman, Hans F.
2012-04-01
We provide a systematic and self-contained exposition of the subject of localized qubits in curved spacetimes. This research was motivated by a simple experimental question: if we move a spatially localized qubit, initially in a state |ψ1>, along some spacetime path Γ from a spacetime point x1 to another point x2, what will the final quantum state |ψ2> be at point x2? This paper addresses this question for two physical realizations of the qubit: spin of a massive fermion and polarization of a photon. Our starting point is the Dirac and Maxwell equations that describe respectively the one-particle states of localized massive fermions and photons. In the WKB limit we show how one can isolate a two-dimensional quantum state which evolves unitarily along Γ. The quantum states for these two realizations are represented by a left-handed 2-spinor in the case of massive fermions and a four-component complex polarization vector in the case of photons. In addition we show how to obtain from this WKB approach a fully general relativistic description of gravitationally induced phases. We use this formalism to describe the gravitational shift in the Colella-Overhauser-Werner 1975 experiment. In the non-relativistic weak field limit our result reduces to the standard formula in the original paper. We provide a concrete physical model for a Stern-Gerlach measurement of spin and obtain a unique spin operator which can be determined given the orientation and velocity of the Stern-Gerlach device and velocity of the massive fermion. Finally, we consider multipartite states and generalize the formalism to incorporate basic elements from quantum information theory such as quantum entanglement, quantum teleportation, and identical particles. The resulting formalism provides a basis for exploring precision quantum measurements of the gravitational field using techniques from quantum information theory.
Deriving Area-storage Curves of Global Reservoirs
Mu, M.; Tang, Q.
2017-12-01
Basic information including capacity, dam height, and largest water area on global reservoirs and dams is well documented in databases such as GRanD (Global Reservoirs and Dams), ICOLD (International Commission on Large Dams). However, though playing a critical role in estimating reservoir storage variations from remote sensing or hydrological models, area-storage (or elevation-storage) curves of reservoirs are not publicly shared. In this paper, we combine Landsat surface water extent, 1 arc-minute global relief model (ETOPO1) and GRanD database to derive area-storage curves of global reservoirs whose area is larger than 1 km2 (6,000 more reservoirs are included). First, the coverage polygon of each reservoir in GRanD is extended to where water was detected by Landsat during 1985-2015. Second, elevation of each pixel in the reservoir is extracted from resampled 30-meter ETOPO1, and then relative depth and frequency of each depth value is calculated. Third, cumulative storage is calculated with increasing water area by every one percent of reservoir coverage area and then the uncalibrated area-storage curve is obtained. Finally, the area-storage curve is linearly calibrated by the ratio of calculated capacity over reported capacity in GRanD. The derived curves are compared with in-situ reservoir data collected in Great Plains Region in US, and the results show that in-situ records are well captured by the derived curves even in relative small reservoirs (several square kilometers). The new derived area-storage curves have the potential to be employed in global monitoring or modelling of reservoirs storage and area variations.
Construction of calibration curve for accountancy tank
International Nuclear Information System (INIS)
Kato, Takayuki; Goto, Yoshiki; Nidaira, Kazuo
2009-01-01
Tanks are equipped in a reprocessing plant for accounting solution of nuclear material. The careful measurement of volume in tanks is very important to implement rigorous accounting of nuclear material. The calibration curve relating the volume and level of solution needs to be constructed, where the level is determined by differential pressure of dip tubes. Several calibration curves are usually employed, but it's not explicitly decided how many segment are used, where to select segment, or what should be the degree of polynomial curve. These parameters, i.e., segment and degree of polynomial curve are mutually interrelated to give the better performance of calibration curve. Here we present the construction technique of giving optimum calibration curves and their characteristics. (author)
MICA: Multiple interval-based curve alignment
Mann, Martin; Kahle, Hans-Peter; Beck, Matthias; Bender, Bela Johannes; Spiecker, Heinrich; Backofen, Rolf
2018-01-01
MICA enables the automatic synchronization of discrete data curves. To this end, characteristic points of the curves' shapes are identified. These landmarks are used within a heuristic curve registration approach to align profile pairs by mapping similar characteristics onto each other. In combination with a progressive alignment scheme, this enables the computation of multiple curve alignments. Multiple curve alignments are needed to derive meaningful representative consensus data of measured time or data series. MICA was already successfully applied to generate representative profiles of tree growth data based on intra-annual wood density profiles or cell formation data. The MICA package provides a command-line and graphical user interface. The R interface enables the direct embedding of multiple curve alignment computation into larger analyses pipelines. Source code, binaries and documentation are freely available at https://github.com/BackofenLab/MICA
Path Integrals and Anomalies in Curved Space
International Nuclear Information System (INIS)
Louko, Jorma
2007-01-01
Bastianelli and van Nieuwenhuizen's monograph 'Path Integrals and Anomalies in Curved Space' collects in one volume the results of the authors' 15-year research programme on anomalies that arise in Feynman diagrams of quantum field theories on curved manifolds. The programme was spurred by the path-integral techniques introduced in Alvarez-Gaume and Witten's renowned 1983 paper on gravitational anomalies which, together with the anomaly cancellation paper by Green and Schwarz, led to the string theory explosion of the 1980s. The authors have produced a tour de force, giving a comprehensive and pedagogical exposition of material that is central to current research. The first part of the book develops from scratch a formalism for defining and evaluating quantum mechanical path integrals in nonlinear sigma models, using time slicing regularization, mode regularization and dimensional regularization. The second part applies this formalism to quantum fields of spin 0, 1/2, 1 and 3/2 and to self-dual antisymmetric tensor fields. The book concludes with a discussion of gravitational anomalies in 10-dimensional supergravities, for both classical and exceptional gauge groups. The target audience is researchers and graduate students in curved spacetime quantum field theory and string theory, and the aims, style and pedagogical level have been chosen with this audience in mind. Path integrals are treated as calculational tools, and the notation and terminology are throughout tailored to calculational convenience, rather than to mathematical rigour. The style is closer to that of an exceedingly thorough and self-contained review article than to that of a textbook. As the authors mention, the first part of the book can be used as an introduction to path integrals in quantum mechanics, although in a classroom setting perhaps more likely as supplementary reading than a primary class text. Readers outside the core audience, including this reviewer, will gain from the book a
Endoscopic sleeve gastroplasty: the learning curve.
Hill, Christine; El Zein, Mohamad; Agnihotri, Abhishek; Dunlap, Margo; Chang, Angela; Agrawal, Alison; Barola, Sindhu; Ngamruengphong, Saowanee; Chen, Yen-I; Kalloo, Anthony N; Khashab, Mouen A; Kumbhari, Vivek
2017-09-01
Endoscopic sleeve gastroplasty (ESG) is gaining traction as a minimally invasive bariatric treatment. Concern that the learning curve may be slow, even among those proficient in endoscopic suturing, is a barrier to widespread implementation of the procedure. Therefore, we aimed to define the learning curve for ESG in a single endoscopist experienced in endoscopic suturing who participated in a 1-day ESG training program. Consecutive patients who underwent ESG between February 2016 and November 2016 were included. The performing endoscopist, who is proficient in endoscopic suturing for non-ESG procedures, participated in a 1-day ESG training session before offering ESG to patients. The outcome measurements were length of procedure (LOP) and number of plications per procedure. Nonlinear regression was used to determine the learning plateau and calculate the learning rate. Twenty-one consecutive patients (8 males), with mean age 47.7 ± 11.2 years and mean body mass index 41.8 ± 8.5 kg/m 2 underwent ESG. LOP decreased significantly across consecutive procedures, with a learning plateau at 101.5 minutes and a learning rate of 7 cases ( P = 0.04). The number of plications per procedure also decreased significantly across consecutive procedures, with a plateau at 8 sutures and a learning rate of 9 cases ( P < 0.001). Further, the average time per plication decreased significantly with consecutive procedures, reaching a plateau at 9 procedures ( P < 0.001). Endoscopists experienced in endoscopic suturing are expected to achieve a reduction in LOP and number of plications per procedure in successive cases, with progress plateauing at 7 and 9 cases, respectively.
Hong Shen
2011-01-01
The concepts of curve profile, curve intercept, curve intercept density, curve profile area density, intersection density in containing intersection (or intersection density relied on intersection reference), curve profile intersection density in surface (or curve intercept intersection density relied on intersection of containing curve), and curve profile area density in surface (AS) were defined. AS expressed the amount of curve profile area of Y phase in the unit containing surface area, S...
Polar representation of centrifugal pump homologous curves
International Nuclear Information System (INIS)
Veloso, Marcelo Antonio; Mattos, Joao Roberto Loureiro de
2008-01-01
Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic parameters: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. Any one of these quantities can be expressed as a function of any two others. The curves showing the relationships between these four variables are called the pump characteristic curves, also referred to as four-quadrant curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, the four-quadrant configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the polar form appears as the simplest way to represent the homologous curves. In the polar method, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a
Duchenne muscular dystrophy: High-resolution melting curve ...
African Journals Online (AJOL)
Duchenne muscular dystrophy: High-resolution melting curve analysis as an affordable diagnostic mutation scanning tool in a South African cohort. ... Genetic screening for D/BMD in South Africa currently includes multiple ligase-dependent probe amplification (MLPA) for exonic deletions and duplications and linkage ...
Flow Curve Determination for Non-Newtonian Fluids.
Tjahjadi, Mahari; Gupta, Santosh K.
1986-01-01
Describes an experimental program to examine flow curve determination for non-Newtonian fluids. Includes apparatus used (a modification of Walawender and Chen's set-up, but using a 50cc buret connected to a glass capillary through a Tygon tube), theoretical information, procedures, and typical results obtained. (JN)
Retention curves measured using pressure plate and pressure membrane apparatus
DEFF Research Database (Denmark)
Hansen, Morten Hjorslev
This report presents a proposal for a test method for the measurement of the retention curve, especially in the high moisture content range, and the pore size distribution of building materials. The test method includes the measurement of apparent density, solid density, and open porosity...
Curves and surfaces for CAGD a practical guide
Farin, Gerald
2002-01-01
This fifth edition has been fully updated to cover the many advances made in CAGD and curve and surface theory since 1997, when the fourth edition appeared. Material has been restructured into theory and applications chapters. The theory material has been streamlined using the blossoming approach; the applications material includes least squares techniques in addition to the traditional interpolation methods. In all other respects, it is, thankfully, the same. This means you get the informal, friendly style and unique approach that has made Curves and Surfaces for CAGD: A Practical Gui
Comparison and evaluation of mathematical lactation curve ...
African Journals Online (AJOL)
p2492989
and on the log of 305-d divided by day in lactation (linear and quadratic) were better than the Gamma function. A study of lactation curves in dairy cattle on farms in central Mexico showed that the Dijkstra function was superior to the Wood, Wilmink and Rook functions for describing the lactation curve (Val-. Arreola et al.
Spectral Curves of Operators with Elliptic Coefficients
Directory of Open Access Journals (Sweden)
J. Chris Eilbeck
2007-03-01
Full Text Available A computer-algebra aided method is carried out, for determining geometric objects associated to differential operators that satisfy the elliptic ansatz. This results in examples of Lamé curves with double reduction and in the explicit reduction of the theta function of a Halphen curve.
Inverse Problem for a Curved Quantum Guide
Directory of Open Access Journals (Sweden)
Laure Cardoulis
2012-01-01
Full Text Available We consider the Dirichlet Laplacian operator −Δ on a curved quantum guide in ℝ n(n=2,3 with an asymptotically straight reference curve. We give uniqueness results for the inverse problem associated to the reconstruction of the curvature by using either observations of spectral data or a boot-strapping method.
Deep-learnt classification of light curves
DEFF Research Database (Denmark)
Mahabal, Ashish; Gieseke, Fabian; Pai, Akshay Sadananda Uppinakudru
2017-01-01
Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and techniques to classify light curves. A common approach is to d...
Learning curves in energy planning models
Energy Technology Data Exchange (ETDEWEB)
Barreto, L.; Kypreos, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1999-08-01
This study describes the endogenous representation of investment cost learning curves into the MARKAL energy planning model. A piece-wise representation of the learning curves is implemented using Mixed Integer Programming. The approach is briefly described and some results are presented. (author) 3 figs., 5 refs.
The Koch curve as a smooth manifold
International Nuclear Information System (INIS)
Epstein, Marcelo; Sniatycki, Jedrzej
2008-01-01
We show that there exists a homeomorphism between the closed interval [0,1] is contained in R and the Koch curve endowed with the subset topology of R 2 . We use this homeomorphism to endow the Koch curve with the structure of a smooth manifold with boundary
Trigonometric Characterization of Some Plane Curves
Indian Academy of Sciences (India)
IAS Admin
There is a way to describe a family of plane curves different from that using Cartesian or po- lar co-ordinates. This is a trigonometric equation involving two angles. In this article, we highlight the fact that trigonometric equations are conve- nient to describe certain one-parameter families of plane curves. In some cases, the ...
A minicourse on moduli of curves
International Nuclear Information System (INIS)
Looijenga, E.
2000-01-01
These are notes that accompany a short course given at the School on Algebraic Geometry 1999 at the ICTP, Trieste. A major goal is to outline various approaches to moduli spaces of curves. In the last part I discuss the algebraic classes that naturally live on these spaces; these can be thought of as the characteristic classes for bundles of curves. (author)
Sibling curves of polynomials | Wiggins | Quaestiones Mathematicae
African Journals Online (AJOL)
Sibling curves were demonstrated in papers [2, 3] as a novel way to visualize the zeros of complex valued functions. In this paper, we continue the work done in those papers by focusing solely on polynomials. We proceed to prove that the number of sibling curves of a polynomial is the degree of the polynomial. Keywords: ...
Measuring Model Rocket Engine Thrust Curves
Penn, Kim; Slaton, William V.
2010-01-01
This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…
Curve Matching with Applications in Medical Imaging
DEFF Research Database (Denmark)
Bauer, Martin; Bruveris, Martins; Harms, Philipp
2015-01-01
In the recent years, Riemannian shape analysis of curves and surfaces has found several applications in medical image analysis. In this paper we present a numerical discretization of second order Sobolev metrics on the space of regular curves in Euclidean space. This class of metrics has several...
Single curved fiber sedimentation under gravity
Xiaoying Rong; Dewei Qi; Junyong Zhu
2005-01-01
Dynamics of single curved fiber sedimentation under the gravity are simulated by using lattice Boltzmann method. The results of migration and rotation of the curved fiber at different Reynolds numbers are reported. The results show that the rotation and migration processes are sensitive to the curvature of the fiber.
Wind Turbine Power Curves Incorporating Turbulence Intensity
DEFF Research Database (Denmark)
Sørensen, Emil Hedevang Lohse
2014-01-01
The performance of a wind turbine in terms of power production (the power curve) is important to the wind energy industry. The current IEC-61400-12-1 standard for power curve evaluation recognizes only the mean wind speed at hub height and the air density as relevant to the power production...
Quantum curves and conformal field theory
Manabe, Masahide; Sułkowski, Piotr
2017-06-01
To a given algebraic curve we assign an infinite family of quantum curves (Schrödinger equations), which are in one-to-one correspondence with, and have the structure of, Virasoro singular vectors. For a spectral curve of a matrix model we build such quantum curves out of an appropriate representation of the Virasoro algebra, encoded in the structure of the α /β -deformed matrix integral and its loop equation. We generalize this construction to a large class of algebraic curves by means of a refined topological recursion. We also specialize this construction to various specific matrix models with polynomial and logarithmic potentials, and among other results, show that various ingredients familiar in the study of conformal field theory (Ward identities, correlation functions and a representation of Virasoro operators acting thereon, Belavin-Polyakov-Zamolodchikov equations) arise upon specialization of our formalism to the multi-Penner matrix model.
Curved and conformal high-pressure vessel
Croteau, Paul F.; Kuczek, Andrzej E.; Zhao, Wenping
2016-10-25
A high-pressure vessel is provided. The high-pressure vessel may comprise a first chamber defined at least partially by a first wall, and a second chamber defined at least partially by the first wall. The first chamber and the second chamber may form a curved contour of the high-pressure vessel. A modular tank assembly is also provided, and may comprise a first mid tube having a convex geometry. The first mid tube may be defined by a first inner wall, a curved wall extending from the first inner wall, and a second inner wall extending from the curved wall. The first inner wall may be disposed at an angle relative to the second inner wall. The first mid tube may further be defined by a short curved wall opposite the curved wall and extending from the second inner wall to the first inner wall.
The South Carolina bridge-scour envelope curves
Benedict, Stephen T.; Feaster, Toby D.; Caldwell, Andral W.
2016-09-30
The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a series of three field investigations to evaluate historical, riverine bridge scour in the Piedmont and Coastal Plain regions of South Carolina. These investigations included data collected at 231 riverine bridges, which lead to the development of bridge-scour envelope curves for clear-water and live-bed components of scour. The application and limitations of the South Carolina bridge-scour envelope curves were documented in four reports, each report addressing selected components of bridge scour. The current investigation (2016) synthesizes the findings of these previous reports into a guidance manual providing an integrated procedure for applying the envelope curves. Additionally, the investigation provides limited verification for selected bridge-scour envelope curves by comparing them to field data collected outside of South Carolina from previously published sources. Although the bridge-scour envelope curves have limitations, they are useful supplementary tools for assessing the potential for scour at riverine bridges in South Carolina.
Asymmetry in Determinants of Running Speed During Curved Sprinting.
Ishimura, Kazuhiro; Sakurai, Shinji
2016-08-01
This study investigates the potential asymmetries between inside and outside legs in determinants of curved running speed. To test these asymmetries, a deterministic model of curved running speed was constructed based on components of step length and frequency, including the distances and times of different step phases, takeoff speed and angle, velocities in different directions, and relative height of the runner's center of gravity. Eighteen athletes sprinted 60 m on the curved path of a 400-m track; trials were recorded using a motion-capture system. The variables were calculated following the deterministic model. The average speeds were identical between the 2 sides; however, the step length and frequency were asymmetric. In straight sprinting, there is a trade-off relationship between the step length and frequency; however, such a trade-off relationship was not observed in each step of curved sprinting in this study. Asymmetric vertical velocity at takeoff resulted in an asymmetric flight distance and time. The runners changed the running direction significantly during the outside foot stance because of the asymmetric centripetal force. Moreover, the outside leg had a larger tangential force and shorter stance time. These asymmetries between legs indicated the outside leg plays an important role in curved sprinting.
Light Curves and Low Phase Angle Photometry for Jupiter Trojans.
Chatelain, Joseph P.; Henry, Todd J.; Scott, Nicholas J.; French, Linda M.; Stephens, Robert D.
2012-08-01
We propose to make light curve observations in both the V and I filters as well as phase curve observations of the 26 brightest Jupiter Trojans, evenly selected from the L4 (Greek) and L5 (Trojan) Lagrangian camps. We are observing these objects as part of a comprehensive effort including 113 Greeks and Trojans using the CTIO 1.0m. With these light curve data we will update previously calculated variation amplitudes and look for color variations that can give details about shapes, orientations, surface features, and ages. None of these targets have published simultaneous color information. The phase information can provide insight into surface detail and composition. These data will also enable calibration of our ongoing photometry program that will reveal the possible origins of the two camps, which remain surprisingly obscure. Furthermore, the light curves are necessary to produce proper phase curves by allowing for the removal of any changes in brightness due to rotation. The proposed observations will comprise a significant portion of the PI's PhD thesis.
Exploring Algorithms for Stellar Light Curves With TESS
Buzasi, Derek
2018-01-01
The Kepler and K2 missions have produced tens of thousands of stellar light curves, which have been used to measure rotation periods, characterize photometric activity levels, and explore phenomena such as differential rotation. The quasi-periodic nature of rotational light curves, combined with the potential presence of additional periodicities not due to rotation, complicates the analysis of these time series and makes characterization of uncertainties difficult. A variety of algorithms have been used for the extraction of rotational signals, including autocorrelation functions, discrete Fourier transforms, Lomb-Scargle periodograms, wavelet transforms, and the Hilbert-Huang transform. In addition, in the case of K2 a number of different pipelines have been used to produce initial detrended light curves from the raw image frames.In the near future, TESS photometry, particularly that deriving from the full-frame images, will dramatically further expand the number of such light curves, but details of the pipeline to be used to produce photometry from the FFIs remain under development. K2 data offers us an opportunity to explore the utility of different reduction and analysis tool combinations applied to these astrophysically important tasks. In this work, we apply a wide range of algorithms to light curves produced by a number of popular K2 pipeline products to better understand the advantages and limitations of each approach and provide guidance for the most reliable and most efficient analysis of TESS stellar data.
Emery, Paul; Solem, Caitlyn; Majer, Istvan; Cappelleri, Joseph C; Tarallo, Miriam
2015-11-01
This retrospective medical chart review aimed to provide a current, real-world overview of biologic usage in patients with rheumatoid arthritis (RA) in Germany, Spain, and the UK, and estimate clinical and healthcare utilization outcomes associated with early versus late treatment. Adults (≥18 years) with a confirmed RA diagnosis between January 2008 and December 2010, who received biologic treatment for ≥3 months and had ≥12 months of follow-up were included. Early treatment was receipt of biologic agent ≤1 year after RA diagnosis. Outcomes included 28-joint disease activity score (DAS28) reduction of ≥1.2 from biologic start and remission (DAS28 < 2.6). Time to outcome was evaluated using Kaplan-Meier curves and log-rank tests. Of 328 patients enrolled (Germany [n = 111], Spain [n = 106], UK [n = 111]), 58.2 % received early biologic (Germany: 55.0 %, UK: 55.9 %, Spain: 64.2 %; p = 0.321). First-line biologics were more frequent in Spain (26.4 %) and Germany (19.8 %) versus the UK (7.2 %; p < 0.001). Late-treated patients were hospitalized more often than early-treated patients (10.5 vs 2.9 % [p = 0.006] for 9.0 vs 5.4 mean inpatient days [p = 0.408]). DAS28 was 5.1 at biologic initiation (n = 310); 73.5 % of patients had a DAS28 decrease of ≥1.2 and 44.5 % achieved remission. More patients had DAS28 decrease of ≥1.2 (79.2 vs 65.9 %; p = 0.009) and remission (51.1 vs 35.6 %; p = 0.007) with early versus late treatment, with a significant difference in Kaplan-Meier curves when indexing on time since diagnosis (p < 0.001) and biologic start (p = 0.024). In RA patients receiving biologic therapy, over half received biologic therapy early. Early initiation was associated with improved clinical outcomes and reduced hospitalization rates versus late treatment.
Deformation and failure of curved colloidal crystal shells.
Negri, Carlotta; Sellerio, Alessandro L; Zapperi, Stefano; Miguel, M Carmen
2015-11-24
Designing and controlling particle self-assembly into robust and reliable high-performance smart materials often involves crystalline ordering in curved spaces. Examples include carbon allotropes like graphene, synthetic materials such as colloidosomes, or biological systems like lipid membranes, solid domains on vesicles, or viral capsids. Despite the relevance of these structures, the irreversible deformation and failure of curved crystals is still mostly unexplored. Here, we report simulation results of the mechanical deformation of colloidal crystalline shells that illustrate the subtle role played by geometrically necessary topological defects in controlling plastic yielding and failure. We observe plastic deformation attributable to the migration and reorientation of grain boundary scars, a collective process assisted by the intermittent proliferation of disclination pairs or abrupt structural failure induced by crack nucleating at defects. Our results provide general guiding principles to optimize the structural and mechanical stability of curved colloidal crystals.
Parametric representation of centrifugal pump homologous curves
International Nuclear Information System (INIS)
Veloso, Marcelo A.; Mattos, Joao R.L. de
2015-01-01
Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic quantities: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. The curves showing the relationships between these four variables are called the pump characteristic curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, this configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the parametric form appears as the simplest way to deal with the homologous curves. In this approach, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a pressurized water reactor (PWR) are transformed to the parametric form. (author)
Parametric representation of centrifugal pump homologous curves
Energy Technology Data Exchange (ETDEWEB)
Veloso, Marcelo A.; Mattos, Joao R.L. de, E-mail: velosom@cdtn.br, E-mail: jrmattos@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)
2015-07-01
Essential for any mathematical model designed to simulate flow transient events caused by pump operations is the pump performance data. The performance of a centrifugal pump is characterized by four basic quantities: the rotational speed, the volumetric flow rate, the dynamic head, and the hydraulic torque. The curves showing the relationships between these four variables are called the pump characteristic curves. The characteristic curves are empirically developed by the pump manufacturer and uniquely describe head and torque as functions of volumetric flow rate and rotation speed. Because of comprising a large amount of points, this configuration is not suitable for computational purposes. However, it can be converted to a simpler form by the development of the homologous curves, in which dynamic head and hydraulic torque ratios are expressed as functions of volumetric flow and rotation speed ratios. The numerical use of the complete set of homologous curves requires specification of sixteen partial curves, being eight for the dynamic head and eight for the hydraulic torque. As a consequence, the handling of homologous curves is still somewhat complicated. In solving flow transient problems that require the pump characteristic data for all the operation zones, the parametric form appears as the simplest way to deal with the homologous curves. In this approach, the complete characteristics of a pump can be described by only two closed curves, one for the dynamic head and other for the hydraulic torque, both in function of a single angular coordinate defined adequately in terms of the quotient between volumetric flow ratio and rotation speed ratio. The usefulness and advantages of this alternative method are demonstrated through a practical example in which the homologous curves for a pump of the type used in the main coolant loops of a pressurized water reactor (PWR) are transformed to the parametric form. (author)
Kono, Yuji; Kawajiri, Hiroyuki; Kamisaka, Kenta; Kamiya, Kuniyasu; Akao, Keigo; Asai, Chikako; Inuzuka, Kana; Yamada, Sumio
2015-02-01
Daily physical inactivity is associated with a substantially increased risk of cardiovascular events. However, the target level of daily physical activity remains unclear. We aimed to evaluate the impact of physical activity on long-term vascular events in patients with mild ischemic stroke. We designed a single hospital-based prospective observational study and studied 166 ischemic stroke patients (mean age: 63.9 ± 9.2) who had a modified Rankin Scale 0-1. We measured the daily step count as a variable of the daily physical activity after three-months from the stroke onset. Other clinical characteristics including age, body mass index, blood pressure, blood laboratory tests, vascular function and medications were also assessed. The primary outcomes were hospitalization due to stroke recurrence, myocardial infarction, angina pectoris and peripheral artery disease. Survival curves were calculated by a Kaplan-Meier survival analysis, and the hazard ratios for recurrences were determined by univariate and multivariate Cox proportional hazards regression models. After a median follow-up periods of 1332 days, 34 vascular events (23 stroke recurrences, 11 coronary artery disease) and 7 drop-outs occurred, and the remaining patients were divided into two groups: the without recurrence group (n = 125) and the with recurrence group (n = 34). The daily step count was lower in the nonsurvivor group than in the survivor group. Univariate and multivariate Cox proportional hazards analyses revealed that the daily step counts was independent predictors of new vascular events. A daily step count cutoff value of 6025 steps per day was determined by analyzing the receiver-operating characteristics that showed a sensitivity of 69.4% and a specificity of 79.4%. The Kaplan-Meier survival curves after a log-rank test showed a significantly lower event rate in the more than 6025 steps per day group compared with the less than 6025 steps per day group (P = 0.0002). The positive and
Hung, Kuo-Feng; Hsu, Ching-Ping; Chiang, Jen-Huai; Lin, Hung-Jen; Kuo, Yi-Ting; Sun, Mao-Feng; Yen, Hung-Rong
2017-03-06
Many patients with gastric cancer seek traditional medicine consultations in Asian countries. This study aimed to investigate the prescription of Chinese herbal medicine (CHM) and its benefits for the patients with gastric cancer in Taiwan. From the Registry for Catastrophic Illness Patients Database, we included all patients with gastric cancer whose age at diagnosis was ≥18 from 1997 to 2010 in Taiwan. We used 1:1 frequency matching by age, sex, Charlson comorbidity score, treatment and index year to compare the CHM users and non-CHM users. We used the Cox regression model to compare the hazard ratios (HR) for the risk of mortality and the Kaplan-Meier curve for the survival time. There was a total of 1333 patients in the CHM-cohort and 44786 patients in the non-CHM cohort. After matching, we compared 962 newly diagnosed CHM users and 962 non-CHM users. Adjusted HRs (aHR) were higher among patients of above 60-year-old group, with a Charlson Comorbidity Index score ≥2 before the index date, and those who need surgery combined with chemotherapy or radiotherapy. CHM users had a lower HR of mortality risk (adjusted HR: 0.55, 95% CI: 0.48-0.62). Compared to the non-CHM users, the aHR among CHM-users is 0.37 (95% CI:0.2-0.67) for those who used CHM more than 180 days annually. The Kaplan-Meier curve revealed that the survival probability was higher for complementary CHM-users. Bai-Hua-She-She-Cao (Herba Hedyotidis Diffusae) was the most commonly used single herb and Xiang-Sha-Liu-Jun-Zi-Tang was the most commonly used herbal formula among CHM prescriptions. Complementary CHM improves the overall survival among patients with gastric cancer in Taiwan. Further ethnopharmacological investigations and clinical trials are required to validate the efficacy and safety. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.
Diekmann, Theresa; Schrems-Hoesl, Laura M; Mardin, Christian Y; Laemmer, Robert; Horn, Folkert K; Kruse, Friedrich E; Schrems, Wolfgang A
2018-02-01
The purpose of this study was to compare the ability of scanning laser polarimetry (SLP) and spectral-domain optical coherence tomography (SD-OCT) to predict future visual field conversion of subjects with ocular hypertension and early glaucoma. All patients were recruited from the Erlangen glaucoma registry and examined using standard automated perimetry, 24-hour intraocular pressure profile, and optic disc photography. Peripapillary retinal nerve fiber layer thickness (RNFL) measurements were obtained by SLP (GDx-VCC) and SD-OCT (Spectralis OCT). Positive and negative predictive values (PPV, NPV) were calculated for morphologic parameters of SLP and SD-OCT. Kaplan-Meier survival curves were plotted and log-rank tests were performed to compare the survival distributions. Contingency tables and Venn-diagrams were calculated to compare the predictive ability. The study included 207 patients-75 with ocular hypertension, 85 with early glaucoma, and 47 controls. Median follow-up was 4.5 years. A total of 29 patients (14.0%) developed visual field conversion during follow-up. SLP temporal-inferior RNFL [0.667; 95% confidence interval (CI), 0.281-0.935] and SD-OCT temporal-inferior RNFL (0.571; 95% CI, 0.317-0.802) achieved the highest PPV; nerve fiber indicator (0.923; 95% CI, 0.876-0.957) and SD-OCT mean (0.898; 95% CI, 0.847-0.937) achieved the highest NPV of all investigated parameters. The Kaplan-Meier curves confirmed significantly higher survival for subjects within normal limits of measurements of both devices (P<0.001). Venn diagrams tested with McNemar test statistics showed no significant difference for PPV (P=0.219) or NPV (P=0.678). Both GDx-VCC and SD-OCT demonstrate comparable results in predicting future visual field conversion if taking typical scans for GDx-VCC. In addition, the likelihood ratios suggest that GDx-VCC's nerve fiber indicator<30 may be the most useful parameter to confirm future nonconversion. (http://www.ClinicalTrials.gov number, NTC
Protective Role of Comfrey Leave Extracts on UV-induced Zebrafish Fin Damage
Cheng, Chien-Chung; Chou, Chi-Yuan; Chang, Yao-Chin; Wang, Hsuan-Wen; Wen, Chi-Chung; Chen, Yau-Hung
2014-01-01
In zebrafish, UV exposure leads to fin malformation phenotypes including fin reduction or absence. The present study evaluated UV-protective activities of comfrey leaves extracts in a zebrafish model by recording fin morphological changes. Chemopreventive effects of comfrey leave extracts were evaluated using Kaplan-Meier analysis and Cox proportional hazards regression. The results showed that (1) the mean times of return to normal fin in the UV+comfrey (50 and 100 ppm) groups were 3.43 and ...
Investigation of learning and experience curves
Energy Technology Data Exchange (ETDEWEB)
Krawiec, F.; Thornton, J.; Edesess, M.
1980-04-01
The applicability of learning and experience curves for predicting future costs of solar technologies is assessed, and the major test case is the production economics of heliostats. Alternative methods for estimating cost reductions in systems manufacture are discussed, and procedures for using learning and experience curves to predict costs are outlined. Because adequate production data often do not exist, production histories of analogous products/processes are analyzed and learning and aggregated cost curves for these surrogates estimated. If the surrogate learning curves apply, they can be used to estimate solar technology costs. The steps involved in generating these cost estimates are given. Second-generation glass-steel and inflated-bubble heliostat design concepts, developed by MDAC and GE, respectively, are described; a costing scenario for 25,000 units/yr is detailed; surrogates for cost analysis are chosen; learning and aggregate cost curves are estimated; and aggregate cost curves for the GE and MDAC designs are estimated. However, an approach that combines a neoclassical production function with a learning-by-doing hypothesis is needed to yield a cost relation compatible with the historical learning curve and the traditional cost function of economic theory.
Maize starch biphasic pasting curves
CSIR Research Space (South Africa)
Nelles, EM
2000-05-01
Full Text Available -susceptible starch. These least 14 water molecules to one anhydrous glucoseproducts may contribute directly to human nu- unit3,4 or enough water so that its addition does not lower the temperature of gelatinisation3,5). Evi- dence for the loss of molecular order... includes: irreversible granule swelling, loss of birefringence, : RVA=Rapid Visco Analyser. loss of crystallinity, viscosity development andCorresponding author: E. M. Nelles. Tel: 27 12 841 2221; Fax: 27 12 841 2386; E-mail: enelles...
Neck curve polynomials in neck rupture model
International Nuclear Information System (INIS)
Kurniadi, Rizal; Perkasa, Yudha S.; Waris, Abdul
2012-01-01
The Neck Rupture Model is a model that explains the scission process which has smallest radius in liquid drop at certain position. Old fashion of rupture position is determined randomly so that has been called as Random Neck Rupture Model (RNRM). The neck curve polynomials have been employed in the Neck Rupture Model for calculation the fission yield of neutron induced fission reaction of 280 X 90 with changing of order of polynomials as well as temperature. The neck curve polynomials approximation shows the important effects in shaping of fission yield curve.
CRC standard curves and surfaces with Mathematica
von Seggern, David H
2006-01-01
Since the publication of the first edition, Mathematica® has matured considerably and the computing power of desktop computers has increased greatly. This enables the presentation of more complex curves and surfaces as well as the efficient computation of formerly prohibitive graphical plots. Incorporating both of these aspects, CRC Standard Curves and Surfaces with Mathematica®, Second Edition is a virtual encyclopedia of curves and functions that depicts nearly all of the standard mathematical functions rendered using Mathematica. While the easy-to-use format remains unchanged from the previ
Morse theory on timelike and causal curves
International Nuclear Information System (INIS)
Everson, J.; Talbot, C.J.
1976-01-01
It is shown that the set of timelike curves in a globally hyperbolic space-time manifold can be given the structure of a Hilbert manifold under a suitable definition of 'timelike.' The causal curves are the topological closure of this manifold. The Lorentzian energy (corresponding to Milnor's energy, except that the Lorentzian inner product is used) is shown to be a Morse function for the space of causal curves. A fixed end point index theorem is obtained in which a lower bound for the index of the Hessian of the Lorentzian energy is given in terms of the sum of the orders of the conjugate points between the end points. (author)
Replication and Analysis of Ebbinghaus' Forgetting Curve.
Murre, Jaap M J; Dros, Joeri
2015-01-01
We present a successful replication of Ebbinghaus' classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We analyze the effects of serial position on forgetting and investigate what mathematical equations present a good fit to the Ebbinghaus forgetting curve and its replications. We conclude that the Ebbinghaus forgetting curve has indeed been replicated and that it is not completely smooth but most probably shows a jump upwards starting at the 24 hour data point.
Replication and Analysis of Ebbinghaus’ Forgetting Curve
Murre, Jaap M. J.; Dros, Joeri
2015-01-01
We present a successful replication of Ebbinghaus’ classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We analyze the effects of serial position on forgetting and investigate what mathematical equations present a good fit to the Ebbinghaus forgetting curve and its replications. We conclude that the Ebbinghaus forgetting curve has indeed been replicated and that it is not completely smooth but most probably shows a jump upwards starting at the 24 hour data point. PMID:26148023
Replication and Analysis of Ebbinghaus' Forgetting Curve.
Directory of Open Access Journals (Sweden)
Jaap M J Murre
Full Text Available We present a successful replication of Ebbinghaus' classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We analyze the effects of serial position on forgetting and investigate what mathematical equations present a good fit to the Ebbinghaus forgetting curve and its replications. We conclude that the Ebbinghaus forgetting curve has indeed been replicated and that it is not completely smooth but most probably shows a jump upwards starting at the 24 hour data point.
Growth curves for twins in Slovenia.
Bricelj, Katja; Blickstein, Isaac; Bržan-Šimenc, Gabrijela; Janša, Vid; Lučovnik, Miha; Verdenik, Ivan; Trojner-Bregar, Andreja; Tul, Nataša
2017-02-01
Abnormalities of fetal growth are more common in twins. We introduce the growth curves for monitoring fetal growth in twin pregnancies in Slovenia. Slovenian National Perinatal Information System for the period between 2002 and 2010 was used to calculate birth weight percentiles for all live born twins for each week from 22nd to 40th week. The calculated percentiles of birth weight for all live-born twins in Slovenia served as the basis for drawing 'growth' curves. The calculated growth curves for twins will help accurately diagnose small or large twin fetuses for their gestational age in the native central European population.
Constructing forward price curves in electricity markets
DEFF Research Database (Denmark)
Fleten, S.-E.; Lemming, Jørgen Kjærgaard
2003-01-01
We present and analyze a method for constructing approximated high-resolution forward price curves in electricity markets. Because a limited number of forward or futures contracts are traded in the market, only a limited picture of the theoretical continuous forward price curve is available...... to the analyst. Our method combines the information contained in observed bid and ask prices with information from the forecasts generated by bottom-up models. As an example, we use information concerning the shape of the seasonal variation from a bottom-up model to improve the forward price curve quoted...
Constructing forward price curves in electricity markets
International Nuclear Information System (INIS)
Fleten, Stein-Erik; Lemming, Jacob
2003-01-01
We present and analyze a method for constructing approximated high-resolution forward price curves in electricity markets. Because a limited number of forward or futures contracts are traded in the market, only a limited picture of the theoretical continuous forward price curve is available to the analyst. Our method combines the information contained in observed bid and ask prices with information from the forecasts generated by bottom-up models. As an example, we use information concerning the shape of the seasonal variation from a bottom-up model to improve the forward price curve quoted on the Nordic power exchange
Curves of restricted type in euclidean spaces
Directory of Open Access Journals (Sweden)
Bengü Kılıç Bayram
2014-01-01
Full Text Available Submanifolds of restricted type were introduced in [7]. In the present study we consider restricted type of curves in Em. We give some special examples. We also show that spherical curve in S2(r C E3 is of restricted type if and only if either ƒ(s is constant or a linear function of s of the form ƒ(s = ±s + b and every closed W - curve of rank k and of length 2(r in E2k is of restricted type.
Learning curve, diagnostic yield and safety of single balloon enteroscopy.
Dutta, Amit Kumar; Sajith, Kattiparambil Gangadharan; Joseph, Anjilivelil J; Simon, Ebby George; Chacko, Ashok
2012-01-01
Single balloon enteroscopy (SBE) is a recently developed diagnostic modality to assess small bowel mucosa. The data on learning curve of SBE is scanty. We aimed to assess the learning curve, diagnostic yield and safety of SBE. All patients who underwent SBE at our centre from December 2007 to December 2010 were included retrospectively. The clinical details, enteroscopy findings and procedure related details were obtained for each patient from a prospectively maintained database. The extent of small bowel visualised with increasing number of procedures by a single endoscopist (Endoscopist A) who performed most of the procedures was used to estimate the learning curve using locally weighted regression curve. The diagnostic yield and complications rates of SBE were also estimated. The study was approved by the institute review board and ethics committee. Ninety SBEs were performed in 84 patients (age: 42+15 years, 27.4% females). 57 procedures were performed (32 antegrade and 25 retrograde) by endoscopist A. There was gradual improvement in the extent of small bowel visualised during the first 15 procedures via antegrade route followed by flattening of curve. The retrograde route showed no definite trend towards improvement during the procedures performed. The overall diagnostic yield of SBE was 32.1%. There was no complication except for mild self-limiting abdominal pain in one patient. SBE via antegrade route has a higher success rate and better learning curve than the retrograde route. SBE is a safe procedure and helps in establishing a diagnosis in one-third of the patients examined.
Phase Curve Analysis of Super-Earth 55 Cancri e
Angelo, Isabel; Hu, Renyu
2018-01-01
One of the primary questions when characterizing Earth-sized and super-Earth-sized exoplanets is whether they have a substantial atmosphere like Earth and Venus, or a bare-rock surface that may come with a tenuous atmosphere like Mercury. Phase curves of the planets in thermal emission provide clues to this question, because a substantial atmosphere would transport heat more efficiently than a bare-rock surface. Analyzing phase curve photometric data around secondary eclipse has previously been used to study energy transport in the atmospheres of hot Jupiters. Here we use phase curve, Spitzer time-series photometry to study the thermal emission properties of the super-Earth exoplanet 55 Cancri e. We utilize a previously developed semi-analytical framework to fit a physical model to infrared photometric data of host star 55 Cancri from the Spitzer telescope IRAC 2 band at 4.5 μm. The model uses various parameters of planetary properties including Bond albedo, heat redistribution efficiency (i.e., the ratio between the radiative timescale and advective timescale of the photosphere), and atmospheric greenhouse factor. The phase curve of 55 Cancri e is dominated by thermal emission with an eastward-shifted hot spot located on the planet surface. We determine the heat redistribution efficiency to be ≈1.47, which implies that the advective timescale is on the same order as the radiative timescale. This requirement from the phase curve cannot be met by the bare-rock planet scenario, because heat transport by currents of molten lava would be too slow. The phase curve thus favors the scenario with a substantial atmosphere. Our constraints on the heat redistribution efficiency translate to a photosphere pressure of ~1.4 bar. The Spitzer IRAC 2 band is thus a window into the deep atmosphere of the planet 55 Cancri e.
Uncovering the skewness news impact curve
Czech Academy of Sciences Publication Activity Database
Anatolyev, Stanislav; Petukhov, A.
2016-01-01
Roč. 14, č. 4 (2016), s. 746-771 ISSN 1479-8409 Institutional support: RVO:67985998 Keywords : conditional skewness * news impact curve * stock returns Subject RIV: AH - Economics Impact factor: 1.800, year: 2016
Twisted vector bundles on pointed nodal curves
Indian Academy of Sciences (India)
Abstract. Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich's and Vistoli's twisted bundles and Gieseker vector bundles.
Safety evaluation of curve warning speed signs.
2011-06-01
This report presents a review of a research effort to evaluate the safety implications of advisory speeds at horizontal curve locations on Oregon rural two-lane highways. The primary goals of this research effort were to characterize driving operatio...
ARC Code TI: ROC Curve Code Augmentation
National Aeronautics and Space Administration — ROC (Receiver Operating Characteristic) curve Code Augmentation was written by Rodney Martin and John Stutz at NASA Ames Research Center and is a modification of ROC...
Twisted Vector Bundles on Pointed Nodal Curves
Indian Academy of Sciences (India)
Abstract. Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich's and Vistoli's twisted bundles and Gieseker vector bundles.
Automorphisms of double coverings of curves
International Nuclear Information System (INIS)
Torres, F.
1994-11-01
We study automorphisms of curves that commute with each other. We prove that the order and the number of fixed points of one of them satisfy certain relations involving those of the other. Then, we specialize our results to the case of double coverings of curves. For instance, if the genus of the curve is at least 4γ + 2 and γ >= 1 (γ = the genus of the covered curve) we prove that the order of an automorphism is bounded above by 2γ + 1 (resp. 4γ + 2) provided it is prime (resp. it has at least five fixed points). We also improve Farkas' bound on the number of fixed points namely 4γ + 4 by showing that it involves the order of the automorphism except in the case of even order when such an improvement is obtained provided the automorphism and the γ-involution has at least one common fixed point. (author). 15 refs
On ``minimally curved spacetimes'' in general relativity
Dadhich, Naresh
1997-01-01
We consider a spacetime corresponding to uniform relativistic potential analogus to Newtonian potential as an example of ``minimally curved spacetime''. We also consider a radially symmetric analogue of the Rindler spacetime of uniform proper acceleration relative to infinity.
Uncovering the skewness news impact curve
Czech Academy of Sciences Publication Activity Database
Anatolyev, Stanislav; Petukhov, A.
2016-01-01
Roč. 14, č. 4 (2016), s. 746-771 ISSN 1479-8409 Institutional support: PRVOUK-P23 Keywords : conditional skewness * news impact curve * stock returns Subject RIV: AH - Economics Impact factor: 1.800, year: 2016
Procedures for setting curve advisory speed.
2009-08-01
The procedures described in this handbook are intended to improve consistency in curve signing and driver compliance with the advisory speed. The handbook describes guidelines for determining when an advisory speed is needed, criteria for identifying...
Prognostic classification index in Iranian colorectal cancer patients: Survival tree analysis
Directory of Open Access Journals (Sweden)
Amal Saki Malehi
2016-01-01
Full Text Available Aims: The aim of this study was to determine the prognostic index for separating homogenous subgroups in colorectal cancer (CRC patients based on clinicopathological characteristics using survival tree analysis. Methods: The current study was conducted at the Research Center of Gastroenterology and Liver Disease, Shahid Beheshti Medical University in Tehran, between January 2004 and January 2009. A total of 739 patients who already have been diagnosed with CRC based on pathologic report were enrolled. The data included demographic and clinical-pathological characteristic of patients. Tree-structured survival analysis based on a recursive partitioning algorithm was implemented to evaluate prognostic factors. The probability curves were calculated according to the Kaplan-Meier method, and the hazard ratio was estimated as an interest effect size. Result: There were 526 males (71.2% of these patients. The mean survival time (from diagnosis time was 42.46± (3.4. Survival tree identified three variables as main prognostic factors and based on their four prognostic subgroups was constructed. The log-rank test showed good separation of survival curves. Patients with Stage I-IIIA and treated with surgery as the first treatment showed low risk (median = 34 months whereas patients with stage IIIB, IV, and more than 68 years have the worse survival outcome (median = 9.5 months. Conclusion: Constructing the prognostic classification index via survival tree can aid the researchers to assess interaction between clinical variables and determining the cumulative effect of these variables on survival outcome.
Wang, Biao; Chen, Gang; Li, Jia; Zeng, Yuanying; Wu, Yunfu; Yan, Xiaoye
2017-01-15
This study examines the clinical utility of plasma neutrophil gelatinase-associated lipocalin (NGAL) as an indicator of myocardial dysfunction and mortality in severe sepsis and septic shock. We designed a prospective cohort study in an intensive care unit, and 53 patients with severe sepsis or septic shock were included. Data were used to determine a relationship between NGAL and the development of myocardial dysfunction and mortality. These associations were determined by the Mann-Whitney test, multiple logistic regression, plotting the receiver operating characteristic (ROC) curve, Kaplan-Meier curves and Spearman test. The High NGAL group had higher need for inotropic/vasopressor support (92% vs. 52%, p=0.0186), higher incidence of regional wall motion abnormalities (46% vs. 13%, p=0.0093), higher B-type natriuretic peptide (BNP) level (p=0.0197), higher cardiac troponin I (cTnI) level (p=0.0016), lower ejection fraction (EF) (pseptic shock was significant. High plasma NGAL correlates with high mortality and myocardial dysfunction in severe sepsis and septic shock. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Curves along which plane waves can interfere
Energy Technology Data Exchange (ETDEWEB)
Karp, S.N.; Machover, M.
1977-07-01
Partial results are given on a conjecture in inverse scattering theory concerning the interference of two-dimensional plane waves. The conjecture states that an odd number of plane waves of the same frequency can only cancel each other at isolated points and not along a simple continuous curve. It is partially confirmed here for curves which are nearly flat at some point. An analysis is also made for various possible nodes for an even number of plane waves.
Replication and Analysis of Ebbinghaus? Forgetting Curve
Murre, Jaap M. J.; Dros, Joeri
2015-01-01
We present a successful replication of Ebbinghaus’ classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We analyze the effects of serial position on forgetting and investigate what mathematical equations present a good fit to the Ebbinghaus forgetting curve and its replications. We conclude that the Ebbingha...
Curvature Entropy for Curved Profile Generation
Ujiie, Yoshiki; Kato, Takeo; Sato, Koichiro; Matsuoka, Yoshiyuki
2012-01-01
In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribu...
Curved twistor spaces and H-space
International Nuclear Information System (INIS)
Tod, K.P.
1980-01-01
The curved twistor space construction of Penrose for anti-self-dual solutions to the Einstein vacuum equations is described. Curved twistor spaces are defined and it is shown with the aid of an example how to obtain them by deforming the complex structure of regions of flat twistor space. The connection of this procedure with Newman's H-space construction via asymptotic twistor space is outlined. (Auth.)
Potential Energy Curve of N2 Revisited
Czech Academy of Sciences Publication Activity Database
Špirko, Vladimír; Xiangzhu, L.; Paldus, J.
2011-01-01
Roč. 76, č. 4 (2011), s. 327-341 ISSN 0010-0765 R&D Projects: GA MŠk LC512; GA ČR GAP208/11/0436 Institutional research plan: CEZ:AV0Z40550506 Keywords : reduced multireference coupled-cluster method * reduced potential curve method * nitrogen molecule potential energy curves Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.283, year: 2011
Verified Indifferentiable Hashing into Elliptic Curves
Barthe, Gilles; Grégoire, Benjamin; Heraud, Sylvain; Olmedo, Federico; Zanella-Béguelin, Santiago
2012-01-01
International audience; Many cryptographic systems based on elliptic curves are proven secure in the Random Oracle Model, assuming there exist probabilistic functions that map elements in some domain (e.g. bitstrings) onto uniformly and independently distributed points in a curve. When implementing such systems, and in order for the proof to carry over to the implementation, those mappings must be instantiated with concrete constructions whose behavior does not deviate significantly from rand...
Constructing elliptic curves from Galois representations
Snowden, Andrew; Tsimerman, Jacob
2017-01-01
Given a non-isotrivial elliptic curve over an arithmetic surface, one obtains a lisse $\\ell$-adic sheaf of rank two over the surface. This lisse sheaf has a number of straightforward properties: cyclotomic determinant, finite ramification, rational traces of Frobenius, and somewhere not potentially good reduction. We prove that any lisse sheaf of rank two possessing these properties comes from an elliptic curve.
Probing exoplanet clouds with optical phase curves.
Muñoz, Antonio García; Isaak, Kate G
2015-11-03
Kepler-7b is to date the only exoplanet for which clouds have been inferred from the optical phase curve--from visible-wavelength whole-disk brightness measurements as a function of orbital phase. Added to this, the fact that the phase curve appears dominated by reflected starlight makes this close-in giant planet a unique study case. Here we investigate the information on coverage and optical properties of the planet clouds contained in the measured phase curve. We generate cloud maps of Kepler-7b and use a multiple-scattering approach to create synthetic phase curves, thus connecting postulated clouds with measurements. We show that optical phase curves can help constrain the composition and size of the cloud particles. Indeed, model fitting for Kepler-7b requires poorly absorbing particles that scatter with low-to-moderate anisotropic efficiency, conclusions consistent with condensates of silicates, perovskite, and silica of submicron radii. We also show that we are limited in our ability to pin down the extent and location of the clouds. These considerations are relevant to the interpretation of optical phase curves with general circulation models. Finally, we estimate that the spherical albedo of Kepler-7b over the Kepler passband is in the range 0.4-0.5.
Environmental bias and elastic curves on surfaces
International Nuclear Information System (INIS)
Guven, Jemal; María Valencia, Dulce; Vázquez-Montejo, Pablo
2014-01-01
The behavior of an elastic curve bound to a surface will reflect the geometry of its environment. This may occur in an obvious way: the curve may deform freely along directions tangent to the surface, but not along the surface normal. However, even if the energy itself is symmetric in the curve's geodesic and normal curvatures, which control these modes, very distinct roles are played by the two. If the elastic curve binds preferentially on one side, or is itself assembled on the surface, not only would one expect the bending moduli associated with the two modes to differ, binding along specific directions, reflected in spontaneous values of these curvatures, may be favored. The shape equations describing the equilibrium states of a surface curve described by an elastic energy accommodating environmental factors will be identified by adapting the method of Lagrange multipliers to the Darboux frame associated with the curve. The forces transmitted to the surface along the surface normal will be determined. Features associated with a number of different energies, both of physical relevance and of mathematical interest, are described. The conservation laws associated with trajectories on surface geometries exhibiting continuous symmetries are also examined. (paper)
Geometric invariant theory for polarized curves
Bini, Gilberto; Melo, Margarida; Viviani, Filippo
2014-01-01
We investigate GIT quotients of polarized curves. More specifically, we study the GIT problem for the Hilbert and Chow schemes of curves of degree d and genus g in a projective space of dimension d-g, as d decreases with respect to g. We prove that the first three values of d at which the GIT quotients change are given by d=a(2g-2) where a=2, 3.5, 4. We show that, for a>4, L. Caporaso's results hold true for both Hilbert and Chow semistability. If 3.5curves. If 2curves. We also analyze in detail the critical values a=3.5 and a=4, where the Hilbert semistable locus is strictly smaller than the Chow semistable locus. As an application, we obtain three compactications of the universal Jacobian over the moduli space of stable curves, weakly-pseudo-stable curves and pseu...
Piecewise power laws in individual learning curves.
Donner, Yoni; Hardy, Joseph L
2015-10-01
The notion that human learning follows a smooth power law (PL) of diminishing gains is well-established in psychology. This characteristic is observed when multiple curves are averaged, potentially masking more complex dynamics underpinning the curves of individual learners. Here, we analyzed 25,280 individual learning curves, each comprising 500 measurements of cognitive performance taken from four cognitive tasks. A piecewise PL (PPL) model explained the individual learning curves significantly better than a single PL, controlling for model complexity. The PPL model allows for multiple PLs connected at different points in the learning process. We also explored the transition dynamics between PL curve component pieces. Performance in later pieces typically surpassed that in earlier pieces, after a brief drop in performance at the transition point. The transition rate was negatively associated with age, even after controlling for overall performance. Our results suggest at least two processes at work in individual learning curves: locally, a gradual, smooth improvement, with diminishing gains within a specific strategy, which is modeled well as a PL; and globally, a discrete sequence of strategy shifts, in which each strategy is better in the long term than the ones preceding it. The piecewise extension of the classic PL of practice has implications for both individual skill acquisition and theories of learning.
Global experience curves for wind farms
International Nuclear Information System (INIS)
Junginger, M.; Faaij, A.; Turkenburg, W.C.
2005-01-01
In order to forecast the technological development and cost of wind turbines and the production costs of wind electricity, frequent use is made of the so-called experience curve concept. Experience curves of wind turbines are generally based on data describing the development of national markets, which cause a number of problems when applied for global assessments. To analyze global wind energy price development more adequately, we compose a global experience curve. First, underlying factors for past and potential future price reductions of wind turbines are analyzed. Also possible implications and pitfalls when applying the experience curve methodology are assessed. Second, we present and discuss a new approach of establishing a global experience curve and thus a global progress ratio for the investment cost of wind farms. Results show that global progress ratios for wind farms may lie between 77% and 85% (with an average of 81%), which is significantly more optimistic than progress ratios applied in most current scenario studies and integrated assessment models. While the findings are based on a limited amount of data, they may indicate faster price reduction opportunities than so far assumed. With this global experience curve we aim to improve the reliability of describing the speed with which global costs of wind power may decline
Analysis of Surface Plasmon Resonance Curves with a Novel Sigmoid-Asymmetric Fitting Algorithm
Directory of Open Access Journals (Sweden)
Daeho Jang
2015-09-01
Full Text Available The present study introduces a novel curve-fitting algorithm for surface plasmon resonance (SPR curves using a self-constructed, wedge-shaped beam type angular interrogation SPR spectroscopy technique. Previous fitting approaches such as asymmetric and polynomial equations are still unsatisfactory for analyzing full SPR curves and their use is limited to determining the resonance angle. In the present study, we developed a sigmoid-asymmetric equation that provides excellent curve-fitting for the whole SPR curve over a range of incident angles, including regions of the critical angle and resonance angle. Regardless of the bulk fluid type (i.e., water and air, the present sigmoid-asymmetric fitting exhibited nearly perfect matching with a full SPR curve, whereas the asymmetric and polynomial curve fitting methods did not. Because the present curve-fitting sigmoid-asymmetric equation can determine the critical angle as well as the resonance angle, the undesired effect caused by the bulk fluid refractive index was excluded by subtracting the critical angle from the resonance angle in real time. In conclusion, the proposed sigmoid-asymmetric curve-fitting algorithm for SPR curves is widely applicable to various SPR measurements, while excluding the effect of bulk fluids on the sensing layer.
Stenting for curved lesions using a novel curved balloon: Preliminary experimental study.
Tomita, Hideshi; Higaki, Takashi; Kobayashi, Toshiki; Fujii, Takanari; Fujimoto, Kazuto
2015-08-01
Stenting may be a compelling approach to dilating curved lesions in congenital heart diseases. However, balloon-expandable stents, which are commonly used for congenital heart diseases, are usually deployed in a straight orientation. In this study, we evaluated the effect of stenting with a novel curved balloon considered to provide better conformability to the curved-angled lesion. In vitro experiments: A Palmaz Genesis(®) stent (Johnson & Johnson, Cordis Co, Bridgewater, NJ, USA) mounted on the Goku(®) curve (Tokai Medical Co. Nagoya, Japan) was dilated in vitro to observe directly the behavior of the stent and balloon assembly during expansion. Animal experiment: A short Express(®) Vascular SD (Boston Scientific Co, Marlborough, MA, USA) stent and a long Express(®) Vascular LD stent (Boston Scientific) mounted on the curved balloon were deployed in the curved vessel of a pig to observe the effect of stenting in vivo. In vitro experiments: Although the stent was dilated in a curved fashion, stent and balloon assembly also rotated conjointly during expansion of its curved portion. In the primary stenting of the short stent, the stent was dilated with rotation of the curved portion. The excised stent conformed to the curved vessel. As the long stent could not be negotiated across the mid-portion with the balloon in expansion when it started curving, the mid-portion of the stent failed to expand fully. Furthermore, the balloon, which became entangled with the stent strut, could not be retrieved even after complete deflation. This novel curved balloon catheter might be used for implantation of the short stent in a curved lesion; however, it should not be used for primary stenting of the long stent. Post-dilation to conform the stent to the angled vessel would be safer than primary stenting irrespective of stent length. Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Noriyuki Oka
Full Text Available In the brain, the mechanisms of attention to the left and the right are known to be different. It is possible that brain activity when driving also differs with different horizontal road alignments (left or right curves, but little is known about this. We found driver brain activity to be different when driving on left and right curves, in an experiment using a large-scale driving simulator and functional near-infrared spectroscopy (fNIRS.The participants were fifteen healthy adults. We created a course simulating an expressway, comprising straight line driving and gentle left and right curves, and monitored the participants under driving conditions, in which they drove at a constant speed of 100 km/h, and under non-driving conditions, in which they simply watched the screen (visual task. Changes in hemoglobin concentrations were monitored at 48 channels including the prefrontal cortex, the premotor cortex, the primary motor cortex and the parietal cortex. From orthogonal vectors of changes in deoxyhemoglobin and changes in oxyhemoglobin, we calculated changes in cerebral oxygen exchange, reflecting neural activity, and statistically compared the resulting values from the right and left curve sections.Under driving conditions, there were no sites where cerebral oxygen exchange increased significantly more during right curves than during left curves (p > 0.05, but cerebral oxygen exchange increased significantly more during left curves (p < 0.05 in the right premotor cortex, the right frontal eye field and the bilateral prefrontal cortex. Under non-driving conditions, increases were significantly greater during left curves (p < 0.05 only in the right frontal eye field.Left curve driving was thus found to require more brain activity at multiple sites, suggesting that left curve driving may require more visual attention than right curve driving. The right frontal eye field was activated under both driving and non-driving conditions.
Biological analysis of Jeffrey nanofluid in a curved channel with heat dissipation.
Maraj, E N; Akbar, Noreen Sher; Nadeem, S
2014-12-01
This study examines the peristaltic flow of Jeffrey nanofluid in a curved channel. The governing equations of Jeffrey nanofluid model for curved channel are derived including the effects of curvature. The highly nonlinear partial differential equations are simplified by using the long wave length and low Reynolds number assumptions. The reduced nonlinear partial differential equations are solved analytically with the help of homotopy perturbation method. The expression for pressure rise is computed through numerical integration. The physical features of pertinent parameters have been discussed by plotting the graphs of pressure rise, velocity, temperature, nanoparticle volume fraction and stream functions. It is observed that the curve-ness of the channel decreases the pressure rise in the peristaltic pumping region. Moreover, curve-ness of the channel effects the fluid flow by decreasing the fluid velocity near inner wall and increasing the velocity near the outer wall of the channel.
Development of the curve of Spee.
Marshall, Steven D; Caspersen, Matthew; Hardinger, Rachel R; Franciscus, Robert G; Aquilino, Steven A; Southard, Thomas E
2008-09-01
Ferdinand Graf von Spee is credited with characterizing human occlusal curvature viewed in the sagittal plane. This naturally occurring phenomenon has clinical importance in orthodontics and restorative dentistry, yet we have little understanding of when, how, or why it develops. The purpose of this study was to expand our understanding by examining the development of the curve of Spee longitudinally in a sample of untreated subjects with normal occlusion from the deciduous dentition to adulthood. Records of 16 male and 17 female subjects from the Iowa Facial Growth Study were selected and examined. The depth of the curve of Spee was measured on their study models at 7 time points from ages 4 (deciduous dentition) to 26 (adult dentition) years. The Wilcoxon signed rank test was used to compare changes in the curve of Spee depth between time points. For each subject, the relative eruption of the mandibular teeth was measured from corresponding cephalometric radiographs, and its contribution to the developing curve of Spee was ascertained. In the deciduous dentition, the curve of Spee is minimal. At mean ages of 4.05 and 5.27 years, the average curve of Spee depths are 0.24 and 0.25 mm, respectively. With change to the transitional dentition, corresponding to the eruption of the mandibular permanent first molars and central incisors (mean age, 6.91 years), the curve of Spee depth increases significantly (P < 0.0001) to a mean maximum depth of 1.32 mm. The curve of Spee then remains essentially unchanged until eruption of the second molars (mean age, 12.38 years), when the depth increases (P < 0.0001) to a mean maximum depth of 2.17 mm. In the adolescent dentition (mean age, 16.21 years), the depth decreases slightly (P = 0.0009) to a mean maximum depth of 1.98 mm, and, in the adult dentition (mean age 26.98 years), the curve remains unchanged (P = 0.66), with a mean maximum depth of 2.02 mm. No significant differences in curve of Spee development were found between
Directory of Open Access Journals (Sweden)
YE Peiyan
2013-04-01
Full Text Available ObjectiveTo identify the risk factors associated with progression of acute-on-chronic liver failure (ACLF occurring in patients with chronic hepatitis B virus (HBV infection (CHB. MethodsThe clinical, demographic, treatment and outcome data of 180 ACLF patients with concomitant CHB managed in our hospital between June 2009 and September 2012 were retrospectively reviewed. Clinical data, taken at baseline, included markers of inflammation/infection (white blood cell (WBC count, coagulation (prothrombin time (PT and prothrombin activity (PTA, and liver function (alanine aminotransferase (ALT, aspartate aminotransferase (AST, total bilirubin (TBil, direct bilirubin (DBil, choninesterase (CHE, albumin (Alb, globulin (Glb, total cholesterol (TC, and ammonia. In-hospital treatments included supplementation with traditional Chinese medicine-based therapies, such as Tuihuang decoction and detoxification enema. The primary outcome was survival during hospitalization. The patients were grouped for analysis according to ACLF stage (early, n=93; mid, n=61; late, n=26 and the risk factors associated with each stage were identified by using univariate (log-rank test and multivariate (Cox’s test regression analyses. The association of risk factors with patient survival was assessed by Kaplan-Meier curve analysis. ResultsThe three ACLF groups showed significantly different amounts of leukocytes, with the late ACLF group showing the highest WBC. The late ACLF group also showed significantly lower Glb and TC. There was a trend in reduced cumulative survival rate and shorter time to death that significantly corresponded to progressive stages of ACLF (early ACLF＞mid ACLF＞late ACLF; all P＜0.001. One-hundred-and-twenty-six (70.0% of the patients died during their hospitalization, and multivariate regression analysis of this entire patient population identified absence of colonic enema, presence of hepatic encephalopathy, presence of hepatorenal syndrome, PTA
Aziz, Hassan A; Singh, Nakul; Bena, James; Wilkinson, Allan; Singh, Arun D
2016-06-01
Vision loss following episcleral brachytherapy for uveal melanoma is difficult to predict for individual patients. To generate a risk calculator for vision loss following episcleral brachytherapy for uveal melanoma. A retrospective review of data was conducted at a multispecialty tertiary care center in Cleveland, Ohio. All patients with primary ciliary body or choroidal melanoma treated with iodine 125 or ruthenium 106 episcleral brachytherapy between January 1, 2004, and December 30, 2013, were included. Univariate and multivariable Cox proportional hazards were used to determine the influence of baseline patient factors on vision loss. Kaplan-Meier curves (log-rank analyses) were used to estimate freedom from vision loss. Bootstrap resampling was performed to bias correct this estimate. Vision loss (to visual acuity [VA] worse than 20/50 and worse than 20/200). A total of 311 patients were included in the study, with a mean (SD) age of 62 (14.7) years at start of treatment and a median follow-up of 36 months (interquartile range, 18-60 months). At presentation, VA was better than or equal to 20/50 in 199 patients (64%) and better than or equal to 20/200 in 289 patients (93%). By Kaplan-Meier analysis, VA less than 20/200 at 3 years was not associated with sex, diabetes, systemic hypertension, or hypercholesterolemia but was associated with history of ocular comorbidities, type of isotope (ruthenium 106 or iodine 125), and initial VA ( >20/50 or radiation dose to the fovea (HR, 1.03; 95% CI, 1.01-1.04; P = .001) and optic disc (HR, 1.01; 95% CI, 1.00-1.01; P = .005), and initial VA worse than 20/50 (HR, 1.85; 95% CI, 1.20-2.85; P = .005) were predictive of vision loss to a VA of less than 20/200. The concordance index for the full data set was 0.77. Using these data, an online risk calculator was developed to predict vision loss following episcleral brachytherapy. The vision prognostication tool presented herein needs to be validated by
Leelahapongsathon, Kansuda; Schukken, Ynte Hein; Pinyopummintr, Tanu; Suriyasathaporn, Witaya
2016-02-01
The objectives of study were to determine the transmission parameters (β), durations of infection, and basic reproductive numbers (R0) of both Streptococcus agalactiae and Streptococcus uberis as pathogens causing mastitis outbreaks in dairy herds. A 10-mo longitudinal study was performed using 2 smallholder dairy herds with mastitis outbreaks caused by Strep. agalactiae and Strep. uberis, respectively. Both herds had poor mastitis control management and did not change their milking management during the entire study period. Quarter milk samples were collected at monthly intervals from all lactating animals in each herd for bacteriological identification. The durations of infection for Strep. uberis intramammary infection (IMI) and Strep. agalactiae IMI were examined using Kaplan-Meier survival curves, and the Kaplan-Meier survival functions for Strep. uberis IMI and Strep. agalactiae IMI were compared using log rank survival-test. The spread of Strep. uberis and Strep. agalactiae through the population was determined by transmission parameter, β, the probability per unit of time that one infectious quarter will infect another quarter, assuming that all other quarters are susceptible. For the Strep. uberis outbreak herd (31 cows), 56 new infections and 28 quarters with spontaneous cure were observed. For the Strep. agalactiae outbreak herd (19 cows), 26 new infections and 9 quarters with spontaneous cure were observed. The duration of infection for Strep. agalactiae (mean=270.84 d) was significantly longer than the duration of infection for Strep. uberis (mean=187.88 d). The transmission parameters (β) estimated (including 95% confidence interval) for Strep. uberis IMI and Strep. agalactiae IMI were 0.0155 (0.0035-0.0693) and 0.0068 (0.0008-0.0606), respectively. The R0 (including 95% confidence interval) during the study were 2.91 (0.63-13.47) and 1.86 (0.21-16.61) for Strep. uberis IMI and Strep. agalactiae IMI, respectively. In conclusion, the transmission
Advanced topics in the arithmetic of elliptic curves
Silverman, Joseph H
1994-01-01
In the introduction to the first volume of The Arithmetic of Elliptic Curves (Springer-Verlag, 1986), I observed that "the theory of elliptic curves is rich, varied, and amazingly vast," and as a consequence, "many important topics had to be omitted." I included a brief introduction to ten additional topics as an appendix to the first volume, with the tacit understanding that eventually there might be a second volume containing the details. You are now holding that second volume. it turned out that even those ten topics would not fit Unfortunately, into a single book, so I was forced to make some choices. The following material is covered in this book: I. Elliptic and modular functions for the full modular group. II. Elliptic curves with complex multiplication. III. Elliptic surfaces and specialization theorems. IV. Neron models, Kodaira-Neron classification of special fibers, Tate's algorithm, and Ogg's conductor-discriminant formula. V. Tate's theory of q-curves over p-adic fields. VI. Neron's theory of can...
Investigation of the bases for use of the KIc curve
International Nuclear Information System (INIS)
McCabe, D.E.; Nanstad, R.K.; Rosenfield, A.R.; Marschall, C.W.; Irwin, G.R.
1991-01-01
Title 10 of the Code of Federal Regulations, Part 50 (10CFR50), Appendix G, establishes the bases for setting allowable pressure and temperature limits on reactors during heatup and cooldown operation. Both the K Ic and K Ia curves are utilized in prescribed ways to maintain reactor vessel structural integrity in the presence of an assumed or actual flaw and operating stresses. Currently, the code uses the K Ia curve, normalized to the RT NDT , to represent the fracture toughness trend for unirradiated and irradiated pressure vessel steels. Although this is clearly a conservative policy, it has been suggested that the K Ic curve is the more appropriate for application to a non-accident operating condition. A number of uncertainties have been identified, however, that might convert normal operating transients into a dynamic loading situation. Those include the introduction of running cracks from local brittle zones, crack pop-ins, reduced toughness from arrested cleavage cracks, description of the K Ic curve for irradiated materials, and other related unresolved issues relative to elastic-plastic fracture mechanics. Some observations and conclusions can be made regarding various aspects of those uncertainties and they are discussed in this paper. A discussion of further work required and under way to address the remaining uncertainties is also presented
Learning curves for strabismus surgery in two ophthalmologists
Directory of Open Access Journals (Sweden)
Yonguk Kim
2015-01-01
Full Text Available Purpose: To identify the average turning point by comparing the learning curves of two surgeons learning to perform strabismus surgery. Materials and Methods: Patients who underwent procedures to correct exotropia between January 2010 and December 2014 followed for at least 3 months were retrospectively assessed. The first 70 patients on whom each of two ophthalmologists (A and B performed surgery to treat strabismus were divided into 7 cohorts comprising 10 patients each based on the chronological order of the surgery. Factors, including patient age, preoperative angle of deviation, operative time, and success or failure of the operation, were compared between the two surgeons. Learning curves were calculated based on changes in operative time and operation success rate. Operation success was determined by measuring the angle of deviation at a distance of 5 m 3 months after the operation. Results: A turning point was observed after 40 cases for Surgeon A and 50 cases for Surgeon B based on the operative time learning curve. No turning point was observed in the operation success rate learning curve based on the absence of a specific trend. Success rate by cohort was not significantly different between the two surgeons (P > 0.05. Surgeon B had a significantly longer mean operative time than Surgeon A (P = 0.045. Conclusions: Approximately 50 cases are required for an ophthalmologist to reach a turning point in strabismus surgery. This outcome can be used as a guideline when training surgeons to perform strabismus surgery.
3D flyable curves for an autonomous aircraft
Bestaoui, Yasmina
2012-11-01
The process of conducting a mission for an autonomous aircraft includes determining the set of waypoints (flight planning) and the path for the aircraft to fly (path planning). The autonomous aircraft is an under-actuated system, having less control inputs than degrees of freedom and has two nonholonomic (non integrable) kinematic constraints. Consequently, the set of feasible trajectories will be restricted and the problem of trajectory generation becomes more complicated than a simple interpolation. Care must be taken in the selection of the basic primitives to respect the kinematic and dynamic limitations. The topic of this paper is trajectory generation using parametric curves. The problem can be formulated as follows: to lead the autonomous aircraft from an initial configuration qi to a final configuration qf in the absence of obstacles, find a trajectory q(t) for 0 ≤t ≤ T. The trajectory can be broken down into a geometric path q(s), s being the curvilinear abscissa and s=s(t) a temporal function. In 2D the curves fall into two categories: • Curves whose coordinates have a closed form expressions, for example B-splines, quintic polynomials or polar splines. • Curves whose curvature is a function of their arc length for example clothoids, cubic spirals, quintic or intrinsic splines. Some 3D solutions will be presented in this paper and their effectiveness discussed towards the problem in hand.
Senkoylu, Alpaslan; Luk, Keith D K; Wong, Yat W; Cheung, Kenneth M C
2014-07-01
Prognosis of minor lumbar curve correction after selective thoracic fusion in idiopathic scoliosis is well defined. However, the prognosis of minor thoracic curve after isolated anterior fusion of the major lumbar curve has not been well described. To define the prognosis of spontaneous thoracic curve correction after selective anterior fusion of the lumbar/thoracolumbar curve in idiopathic scoliosis. A retrospective cohort study on the prognosis of the minor curve after selective anterior correction and fusion of the lumbar/thoracolumbar curve in idiopathic scoliosis. Idiopathic lumbar scoliosis patients treated with anterior spinal fusion. The Scoliosis Research Society 22 questionnaire was used as an outcome measure at the final follow-up. Twenty-eight patients were included in this study. Four patients were male, 24 patients were female, and average age at the time of surgery was 16 years. Mean follow-up was 48 months. According to the Lenke Classification, 22 patients were 5CN, 5 were 5C-, and 1 was 5C+. All operations were performed in the same institution. Standing long posterior-anterior and lateral radiographs were taken just before surgery, 1 week after surgery, and at final follow-up. The mean preoperative Cobb angle of the lumbar (major) curve was 53° (standard deviation [SD]=8.6) and that of the thoracic (minor) curve was 38.4° (SD=6.24). The lumbar and thoracic curves were corrected to 10° (SD=7.6) and 25° (SD=8.3) postoperatively and measured 17° (SD=10.6) and 27° (SD=7.7), respectively, at the last follow-up. There was a significant difference between the preoperative and postoperative measurements of the minor curves (p.05). Regarding the overall sagittal balance, there was no significant difference between preoperative, early, and late postoperative measurements (p>.05). Selective anterior fusion of the major thoracolumbar/lumbar curve was an effective method for the treatment of Lenke Type 5C curves. Minor thoracic curves did not progress
The Biasing Effects of Unmodeled ARMA Time Series Processes on Latent Growth Curve Model Estimates
Sivo, Stephen; Fan, Xitao; Witta, Lea
2005-01-01
The purpose of this study was to evaluate the robustness of estimated growth curve models when there is stationary autocorrelation among manifest variable errors. The results suggest that when, in practice, growth curve models are fitted to longitudinal data, alternative rival hypotheses to consider would include growth models that also specify…
IMPA-ICTP School on Moduli of Curves
Ciliberto, Ciro; Esteves, Eduardo; Melo, Margarida; Voisin, Claire
2017-01-01
Providing a timely description of the present state of the art of moduli spaces of curves and their geometry, this volume is written in a way which will make it extremely useful both for young people who want to approach this important field, and also for established researchers, who will find references, problems, original expositions, new viewpoints, etc. The book collects the lecture notes of a number of leading algebraic geometers and in particular specialists in the field of moduli spaces of curves and their geometry. This is an important subject in algebraic geometry and complex analysis which has seen spectacular developments in recent decades, with important applications to other parts of mathematics such as birational geometry and enumerative geometry, and to other sciences, including physics. The themes treated are classical but with a constant look to modern developments (see Cascini, Debarre, Farkas, and Sernesi's contributions), and include very new material, such as Bridgeland stability (see M...
Growth Curve Models and Applications : Indian Statistical Institute
2017-01-01
Growth curve models in longitudinal studies are widely used to model population size, body height, biomass, fungal growth, and other variables in the biological sciences, but these statistical methods for modeling growth curves and analyzing longitudinal data also extend to general statistics, economics, public health, demographics, epidemiology, SQC, sociology, nano-biotechnology, fluid mechanics, and other applied areas. There is no one-size-fits-all approach to growth measurement. The selected papers in this volume build on presentations from the GCM workshop held at the Indian Statistical Institute, Giridih, on March 28-29, 2016. They represent recent trends in GCM research on different subject areas, both theoretical and applied. This book includes tools and possibilities for further work through new techniques and modification of existing ones. The volume includes original studies, theoretical findings and case studies from a wide range of app lied work, and these contributions have been externally r...
A global motion planner for curve-tracing robots
Energy Technology Data Exchange (ETDEWEB)
Hwang, Y.K.; Chen, P.C.; Neidigk, D.D. [Sandia National Labs., Albuquerque, NM (United States); Maciejewski, A.A. [Purdue Univ., Lafayette, IN (United States)
1993-11-01
We present a global motion planner for tracing curves in three dimensions with robot manipulator tool frames. This planner generates an efficient motion satisfying three types of constraints; constraints on the tool tip for curve tracing, robot kinematic constraints and robot-link collision constraints. Motions are planned using a global search algorithm and a local planner based on a potential-field approach. This planner can be used with potential-field approach. This planner can be used with any robots including redundant manipulators, and can any robots including redundant manipulators, and can control the trade-offs between its algorithmic completeness and computation time. It can be applied in many robotic tasks such as seam welding, caulking, edge deburrring and chamfering, and is expected to reduce motion programming times from days to minutes.
Twists of genus three curves and their Jacobians
Meagher, Stephen
2008-01-01
An algebraic curve is a curve defined over by polynomial equations with coefficients in a given field. This thesis treats problems which arise from genus three curves over finite fields. An important tool for treating such curves is the Jacobian variety of the curve. One problem is how many points
Some issues using the master curve concept
International Nuclear Information System (INIS)
Viehrig, H.W.; Boehmert, J.
2000-01-01
The state-of-the-art structural integrity assessment of reactor pressure vessels (RPV) is based on the Reference Temperature Concept, initially proposed by the American Society of Mechanical Engineers (ASME). An experimentally ensured fracture toughness curve was constructed as the lower boundary of the available fracture toughness, K IC , of RPV steels. This conservative curve describing K IC as a function of temperature is used as a universal curve. For different RPV steels the curve is placed on the temperature axis over a reference temperature. In the initial state the nil-ductility-transition temperature (RT NDT ) is applied as reference temperature. The ductile to brittle transition temperature (DBTT) shift caused by the neutron irradiation is determined by Charpy V impact tests. The Charpy V DBTT shift is one of the results of the RPV surveillance programmes. The concept based on the ASME curve has the following disadvantages: - it is not consistent since it links fracture mechanical and technological parameters and - margins of safety and uncertainties cannot be quantified. (orig.)
Brachistochrone curve of a fluid filled cylinder
Sarma, Srikanth; Raja, Sharan; Mahapatra, Pallab Sinha; Panchangnula, Mahesh
2017-11-01
The brachistochrone curve for a non-dissipative particle tries to maximize inertia of the particle but for a fluid filled cylinder, increasing inertia would amount to high dissipative losses. Hence the trade off between inertia and dissipation plays a vital role in the dynamics of a fluid filled cylinder. This trade off manifests itself in the form of an integro-differential equation governing the angular acceleration of the cylinder. Here, we compute the brachistochrone curve using optimal control principles and investigate the effect of the fore mentioned trade off on the deviation of the brachistochrone curve from that of a non-dissipative particle. Also, we investigate the effects of the non-dimensional parameters of the problem on the shape of the brachistochrone curve. We analyze the dissipation rate during the cylinder's motion and show that energy based arguments don't hold good for a fluid filled cylinder. We then analyze the stability of the time varying fluid flow in the cylinder and find an admissible region for the terminal point which would ensure the stability of the fluid flow as the cylinder rolls over the brachistochrone curve.
Applications for curved glass in buildings
Directory of Open Access Journals (Sweden)
Jürgen Neugebauer
2015-05-01
Full Text Available In the last years an increase of the number of building projects with built-in curved glass can be observed. The applications can principally be curved monolithic glass, laminated safety glass or insulated glass. This fact makes it absolute of interest to make more investigations in this field. The investigations can be focused on e.g. the process of the bending of the glass to bring it into a certain shape, or the very difficult topic of pre-stressing it. The state of the art of the production process of such glass shows some different ways to produce curved glass. The most used way is to bend the glass at a high temperature of more than 550° Celsius. Another kind of curved glass can be achieved in combination with the laminating process. With the cooling down at the end of the laminating process the interlayer becomes stiff enough to hold the shape by activated shear forces between the glass layers. Another possibility is to produce flat glass and bend it while mounting the glass. The question how to pre-stress curved glass is on the very first beginning of investigations. All these different processes are on the first view very easy but very difficult in the detail.
Comparison of power curve monitoring methods
Directory of Open Access Journals (Sweden)
Cambron Philippe
2017-01-01
Full Text Available Performance monitoring is an important aspect of operating wind farms. This can be done through the power curve monitoring (PCM of wind turbines (WT. In the past years, important work has been conducted on PCM. Various methodologies have been proposed, each one with interesting results. However, it is difficult to compare these methods because they have been developed using their respective data sets. The objective of this actual work is to compare some of the proposed PCM methods using common data sets. The metric used to compare the PCM methods is the time needed to detect a change in the power curve. Two power curve models will be covered to establish the effect the model type has on the monitoring outcomes. Each model was tested with two control charts. Other methodologies and metrics proposed in the literature for power curve monitoring such as areas under the power curve and the use of statistical copulas have also been covered. Results demonstrate that model-based PCM methods are more reliable at the detecting a performance change than other methodologies and that the effectiveness of the control chart depends on the types of shift observed.
Critical Factors for Inducing Curved Somatosensory Saccades
Directory of Open Access Journals (Sweden)
Tamami Nakano
2011-10-01
Full Text Available We are able to make a saccade toward a tactile stimuli to one hand, but trajectories of many saccades curved markedly when the arms were crossed (Groh & Sparks, 2006. However, it remains unknown why some curved and others did not. We therefore examined critical factors for inducing the curved somatosensory saccades. Participants made a saccade as soon as possible from a central fixation point toward a tactile stimulus delivered to one of the two hands, and switched between arms-crossed and arms-uncrossed postures every 6 trials. Trajectories were generally straight when the arms were uncrossed, but all participants made curved saccades when the arms were crossed (12–64%. We found that the probability of curved saccades depended critically on the onset latency: the probability was less than 5% when the latency was larger than 250 ms, but the probability increased up to 70–80% when the onset latency was 160 ms. This relationship was shared across participants. The results suggest that a touch in the arms-crossed posture was always mapped to the wrong hand in the initial phase up to 160 ms, and then remapped to the correct hand during the next 100 ms by some fundamental neural mechanisms shared across participants.
Standing sausage modes in curved coronal slabs
Pascoe, D. J.; Nakariakov, V. M.
2016-09-01
Context. Magnetohydrodynamic waveguides such as dense coronal loops can support standing modes. The ratios of the periods of oscillations for different longitudinal harmonics depend on the dispersive nature of the waveguide and so may be used as a seismological tool to determine coronal parameters. Aims: We extend models of standing sausage modes in low β coronal loops to include the effects of loop curvature. The behaviour of standing sausage modes in this geometry is used to explain the properties of observed oscillations that cannot be accounted for using straight loop models. Methods: We perform 2D numerical simulations of an oscillating coronal loop, modelled as a dense slab embedded in a potential magnetic field. The loop is field-aligned and so experiences expansion with height in addition to being curved. Standing sausage modes are excited by compressive perturbations of the loop and their properties are studied. Results: The spatial profiles of standing sausage modes are found to be modified by the expanding loop geometry typical for flaring loops and modelled by a potential magnetic field in our simulations. Longitudinal harmonics of order n > 1 have anti-nodes that are shifted towards the loop apex and the amplitude of anti-nodes near the loop apex is smaller than those near the loop footpoints. Conclusions: We find that the observation of standing sausage modes by the Nobeyama Radioheliograph in a flaring coronal loop on 12 January 2000 is consistent with interpretation in terms of the global mode (n = 1) and third harmonic (n = 3). This interpretation accounts for the period ratio and spatial structure of the observed oscillations.
galkin: A new compilation of Milky Way rotation curve data
Directory of Open Access Journals (Sweden)
Miguel Pato
2017-01-01
Full Text Available We present galkin, a novel compilation of kinematic measurements tracing the rotation curve of our Galaxy together with a tool to treat the data. The compilation is optimised to Galactocentric radii between 3 and 20 kpc and includes the kinematics of gas, stars and masers in a total of 2780 measurements carefully collected from almost four decades of literature. A simple, user-friendly tool is provided to select, treat and retrieve the full database.
Numerical Simulation of Particle Motion in a Curved Channel
Liu, Yi; Nie, Deming
2018-01-01
In this work the lattice Boltzmann method (LBM) is used to numerically study the motion of a circular particle in a curved channel at intermediate Reynolds numbers (Re). The effects of the Reynolds number and the initial particle position are taken into account. Numerical results include the streamlines, particle trajectories and final equilibrium positions. It has been found that the particle is likely to migrate to a similar equilibrium position irrespective of its initial position when Re is large.
Spiess, Philippe E; Levy, David A; Mouraviev, Vladimir; Pisters, Louis L; Jones, J Stephen
2013-08-01
What's known on the subject? and what does the study add?: Previous studies have identified the most important prognostic factors of the likely outcomes of salvage prostate whole-gland ablation, including initial clinical stage, biopsy Gleason score, and PSA (total and doubling time). There is potential for further optimization of candidate selection for salvage cryoablation with curative intent and nadir PSA achieved after whole-gland cryotherapy may provide additional prognostic value. The study shows that the most important prognostic factors of biochemical progression-free survival for patients who have undergone whole-gland salvage prostate cryotherapy are nadir PSA achieved after therapy and pre-therapy biopsy Gleason score. Based on these two prognostic variables, we have identified risk stratification groups (low, intermediate and high) which help predict the expected outcomes of salvage whole-gland prostate cryotherapy in a given patient. This risk stratification constitutes a useful clinical tool in defining which patients maybe best suited for this local salvage treatment method. To assess the prognostic variables predicting the risk of biochemical progression-free survival (bPFS) after salvage prostate whole-gland cryotherapy using the Phoenix definition of bPFS. A total of 132 patients underwent prostate whole-gland salvage cryotherapy with curative intent. No patient underwent neoadjuvant/adjuvant hormonal ablative therapy, and all had extended post-salvage prostate-specific antigen (PSA) follow-up data. Cox univariate and multivariate logistic regression analyses of potential predictors of bPFS were conducted. Kaplan-Meier analyses of bPFS was also performed. At a mean (range) follow-up of 4.3 (0.9-12.7) years, the median (range) post-cryotherapy nadir PSA achieved was 0.17 (0-33.9) ng/mL. On multivariate analysis, predictors of bPFS were nadir PSA post-cryotherapy and pre-salvage biopsy Gleason score (P 2.5 ng/mL or biopsy Gleason score ≥ 7, with
Clinical features and disease progression in moyamoya disease patients with Graves disease.
Chen, Jian-Bin; Lei, Ding; He, Min; Sun, Hong; Liu, Yi; Zhang, Heng; You, Chao; Zhou, Liang-Xue; Zhou, Ling-Xue
2015-10-01
The present study aimed to clarify the incidence and clinical features of disease progression in adult moyamoya disease (MMD) patients with Graves disease (GD) for better management of these patients. During the past 18 years, 320 adult Chinese patients at West China Hospital were diagnosed with MMD, and 29 were also diagnosed with GD. A total of 170 patients (25 with GD; 145 without GD) were included in this study and were followed up. The mean follow-up was 106.4 ± 48.6 months (range 6-216 months). The progression of the occlusive lesions in the major intracranial arteries was measured using cerebral angiography and was evaluated according to Suzuki's angiographic staging. Information about cerebrovascular strokes was obtained from the records of patients' recent clinical visits. Both angiographic progression and strokes were analyzed to estimate the incidences of angiographic progression and strokes using Kaplan-Meier analysis. A multivariate logistic regression model was used to test the effects of sex, age at MMD onset, disease type, strokes, and GD on the onset of MMD progression during follow-up. During follow-up, the incidence of disease progression in MMD patients with GD was significantly higher than in patients without GD (40.0% vs 20.7%, respectively; p = 0.036). The interval between initial diagnosis and disease progression was significantly shorter in MMD patients with GD than in patients without GD (p = 0.041). Disease progression occurred in both unilateral MMD and bilateral MMD, but the interval before disease progression in patients with unilateral disease was significantly longer than in patients with bilateral disease (p = 0.021). The incidence of strokes in MMD patients with GD was significantly higher than in patients without GD (48% vs 26.2%, respectively; p = 0.027). The Kaplan-Meier survival curve showed significant differences in the incidence of disease progression (p = 0.038, log-rank test) and strokes (p = 0.031, log-rank test) between
Çalışkan, Mehmet Kemal; Güneri, Pelin
2017-01-01
The aim of this retrospective study was to evaluate the influence of various predictors on healing outcomes after direct pulp capping (DPC) using either mineral trioxide aggregate (MTA) or calcium hydroxide (CH) as a pulp-dressing agent. The present study included 172 mature asymptomatic permanent teeth with carious-exposed pulp. The teeth were treated with DPC, using either MTA or CH, and the treatment outcome was evaluated clinically and radiographically. The effect of potential clinical variables on the treatment outcome of DPC was evaluated clinically and radiographically during a 24-72-month follow-up. In order to assess the cumulative successes of CH and MTA after DPC, Kaplan-Meier survival analysis and log-rank test was used. The subgroups were compared by means of the log-rank test. Also, univariate Cox regression analysis was used to determine hazard ratio of clinical variables. One hundred and fifty-two teeth of 172 capped teeth were available for follow-up, with an overall recall rate of 87.6 % for MTA vs 89.3 % for CH. The mean period of follow-up was 37.3 (±17.2) months. Overall success rates of 85.9 and 77.6 % in the MTA and CH groups were observed, respectively. The cumulative success rate of both materials was not statistically different when analysed by the Cox proportional hazard regression analysis (P = 0.282). The Kaplan-Meier survival curves revealed that 2-year overall pulp survival was 91.4 %, while the 4- and 6-year survival rates were 84 and 65 %, respectively. None of the clinical variables had a considerable influence on the outcome of DPC (p > 0.05). MTA-capped teeth demonstrated a slightly higher success rate than CH, revealing that it can be recommended as a reliable direct pulp-capping material. None of the clinical variables investigated significantly affected posttreatment healing. DPC with MTA is a straightforward procedure with favourable outcome of 24- to 72-month follow-ups in vital mature asymptomatic permanent teeth
Ruijs, Wilhelmina L M; Hautvast, Jeannine L A; Akkermans, Reinier P; Hulscher, Marlies E J L; van der Velden, Koos
2011-08-24
In the Netherlands, epidemics of vaccine preventable diseases are largely confined to an orthodox protestant minority with religious objections to vaccination. The clustering of unvaccinated children in orthodox protestant schools can foster the spread of epidemics. School closure has nevertheless not been practiced up until now. A mumps epidemic in 2007-2008 gave us an opportunity to study the role of schools in the spread of a vaccine preventable disease in a village with low vaccination coverage. A retrospective cohort study was conducted among the students in four elementary schools and their siblings. The following information was collected for each child: having had the mumps or not and when, school, age, MMR vaccination status, household size, presence of high school students in the household, religious denomination, and home village. The spread of mumps among unvaccinated children was compared for the four schools in a Kaplan-Meier analysis using a log-rank test. Cox proportional hazard analyses were performed to test for the influence of other factors. To correct for confounding, a univariate Cox regression model with only school included as a determinant was compared to a multivariate regression model containing all possible confounders. Out of 650 households with children at the schools, 54% completed a questionnaire, which provided information on 1191 children. For the unvaccinated children (N = 769), the Kaplan-Meier curves showed significant differences among the schools in their cumulative attack rates. After correction for confounding, the Cox regression analysis showed the hazard of mumps to be higher in one orthodox protestant school compared to the other (hazard ratio 1.43, p < 0.001). Household size independently influenced the hazard of mumps (hazard ratio 1.44, p < 0.005) with children in larger households running a greater risk. If and when unvaccinated children got mumps was determined by the particular school the children and their siblings
Comparison of ductile-to-brittle transition curve fitting approaches
International Nuclear Information System (INIS)
Cao, L.W.; Wu, S.J.; Flewitt, P.E.J.
2012-01-01
Ductile-to-brittle transition (DBT) curve fitting approaches are compared over the transition temperature range for reactor pressure vessel steels with different kinds of data, including Charpy-V notch impact energy data and fracture toughness data. Three DBT curve fitting methods have been frequently used in the past, including the Burr S-Weibull and tanh distributions. In general there is greater scatter associated with test data obtained within the transition region. Therefore these methods give results with different accuracies, especially when fitting to small quantities of data. The comparison shows that the Burr distribution and tanh distribution can almost equally fit well distributed and large data sets extending across the test temperature range to include the upper and lower shelves. The S-Weibull distribution fit is poor for the lower shelf of the DBT curve. Overall for both large and small quantities of measured data the Burr distribution provides the best description. - Highlights: ► Burr distribution offers a better fit than that of a S-Weibull and tanh fit. ► Burr and tanh methods show similar fitting ability for a large data set. ► Burr method can fit sparse data well distributed across the test temperature. ► S-Weibull method cannot fit the lower shelf well and show poor fitting quality.
Asymmetry dependence of the nuclear caloric curve
International Nuclear Information System (INIS)
McIntosh, A.B.; Bonasera, A.; Cammarata, P.; Hagel, K.; Heilborn, L.; Kohley, Z.; Mabiala, J.; May, L.W.; Marini, P.; Raphelt, A.; Souliotis, G.A.; Wuenschel, S.; Zarrella, A.; Yennello, S.J.
2013-01-01
A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron–proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A=50. The caloric curve extracted with the momentum quadrupole fluctuation thermometer shows that the temperature varies linearly with quasi-projectile asymmetry (N−Z)/A . An increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei
The genus curve of the Abell clusters
Rhoads, James E.; Gott, J. Richard, III; Postman, Marc
1994-01-01
We study the topology of large-scale structure through a genus curve measurement of the recent Abell catalog redshift survey of Postman, Huchra, and Geller (1992). The structure is found to be spongelike near median density and to exhibit isolated superclusters and voids at high and low densities, respectively. The genus curve shows a slight shift toward 'meatball' topology, but remains consistent with the hypothesis of Gaussian random phase initial conditions. The amplitude of the genus curve corresponds to a power-law spectrum with index n = 0.21(sub -0.47 sup +0.43) on scales of 48/h Mpc or to a cold dark matter power spectrum with omega h = 0.36(sub -0.17 sup +0.46).
Energy efficiency and load curve impacts
International Nuclear Information System (INIS)
Feilberg, Nicolai
2002-01-01
One of SINTEF Energy Research's European RTD projects is the two-year EFFLOCOM (Energy EFFiciency and LOad curve impacts of COMmercial development in competitive markets). This project will determine the end-user response of different market-related services offered in deregulated power markets. The project will investigate the possibility of influencing load curves by using different price signals and two-way communications via Internet. The partners are from Denmark. Finland, England, France and Norway. SINTEF Energy Research is in charge of the project management. During the project, the changes in load curves will he studied in the in the participating countries before and after deregulation. Specific issues are the use of ICT, time- and situation-dependent tariffs and smart-house technology. The project will consist of 5 work packages that will give recommendations about new methods, guidelines and tools to promote effective use of energy in the partner countries. The total budget is EUR 692 000. (author)
Differential geometry of curves and surfaces
Banchoff, Thomas F
2010-01-01
Students and professors of an undergraduate course in differential geometry will appreciate the clear exposition and comprehensive exercises in this book that focuses on the geometric properties of curves and surfaces, one- and two-dimensional objects in Euclidean space. The problems generally relate to questions of local properties (the properties observed at a point on the curve or surface) or global properties (the properties of the object as a whole). Some of the more interesting theorems explore relationships between local and global properties. A special feature is the availability of accompanying online interactive java applets coordinated with each section. The applets allow students to investigate and manipulate curves and surfaces to develop intuition and to help analyze geometric phenomena.
The many radial access learning curves.
Hillegass, William B
2017-04-01
The radial approach to endovascular procedures has a series of learning curves: diagnostic heart catheterization, low-risk settings and "straightforward" percutaneous coronary intervention, high-risk settings, and complex coronary intervention, and peripheral vascular angiography and intervention. For diagnostic and low-risk interventional procedures, incremental improvements in technical success and safety are observed in the initial 200 procedures for most operators compared to highly experienced operators. Formal didactic training and ongoing support/review from an experienced radial operator(s) may expedite surmounting the series of radial learning curves while maintaining optimal procedural success and safety. Advances in technology and understanding will require the most experienced radial operators to continually embrace their next learning curve. © 2017 Wiley Periodicals, Inc.
Surface growth kinematics via local curve evolution
Moulton, Derek E.
2012-11-18
A mathematical framework is developed to model the kinematics of surface growth for objects that can be generated by evolving a curve in space, such as seashells and horns. Growth is dictated by a growth velocity vector field defined at every point on a generating curve. A local orthonormal basis is attached to each point of the generating curve and the velocity field is given in terms of the local coordinate directions, leading to a fully local and elegant mathematical structure. Several examples of increasing complexity are provided, and we demonstrate how biologically relevant structures such as logarithmic shells and horns emerge as analytical solutions of the kinematics equations with a small number of parameters that can be linked to the underlying growth process. Direct access to cell tracks and local orientation enables for connections to be made to the underlying growth process. © 2012 Springer-Verlag Berlin Heidelberg.
Minimal families of curves on surfaces
Lubbes, Niels
2014-11-01
A minimal family of curves on an embedded surface is defined as a 1-dimensional family of rational curves of minimal degree, which cover the surface. We classify such minimal families using constructive methods. This allows us to compute the minimal families of a given surface.The classification of minimal families of curves can be reduced to the classification of minimal families which cover weak Del Pezzo surfaces. We classify the minimal families of weak Del Pezzo surfaces and present a table with the number of minimal families of each weak Del Pezzo surface up to Weyl equivalence.As an application of this classification we generalize some results of Schicho. We classify algebraic surfaces that carry a family of conics. We determine the minimal lexicographic degree for the parametrization of a surface that carries at least 2 minimal families. © 2014 Elsevier B.V.
Fellowship training as a modifier of the surgical learning curve
Bianco, FJ; Cronin, AM; Klein, EA; Pontes, JE; Scardino, PT; Vickers, AJ
2010-01-01
Purpose To investigate the effects of fellowship training on the learning curve for cancer control after open radical prostatectomy. Methods The study cohort included 7765 prostate cancer patients who were treated with radical prostatectomy by one of 72 surgeons at four major U.S. academic medical centers between 1987 and 2003. Multivariable models were used to determine the learning curves for biochemical recurrence and surgical margins, separately for surgeons with and without fellowship training, with adjustment for standard prognostic variables. Results Initial results of fellowship and non-fellowship trained surgeons were similar (5-year probability of recurrence for first case 19.4% vs 18.3%, respectively; absolute difference −1.1%; 95% CI −5.5% to 3.0%; p=0.7). However, the rate of learning was faster among fellowship trained surgeons (p=0.006), resulting in superior cancer control overall for fellowship trained surgeons (p=0.001; difference 4.7%; 95% CI 2.6% to 7.4%). In contrast, fellowship trained surgeons started off with superior positive margin rates (p=0.005; 36% vs 42%; absolute difference 6%; 95% CI 1% to 10%), but there was no obvious difference in the subsequent learning curve (p=0.9). Conclusions The learning curve for biochemical recurrence depends on surgical training, whereas the learning curve for surgical margins does not. This suggests that improvements in margin rates result from reflection on specific aspects of surgical procedure, while improvements in biochemical recurrence occur by some general process of improved surgical technique. Further research into the mechanisms of surgical learning is warranted. PMID:20520043
Demand curves for hypothetical cocaine in cocaine-dependent individuals.
Bruner, Natalie R; Johnson, Matthew W
2014-03-01
Drug purchasing tasks have been successfully used to examine demand for hypothetical consumption of abused drugs including heroin, nicotine, and alcohol. In these tasks, drug users make hypothetical choices whether to buy drugs, and if so, at what quantity, at various potential prices. These tasks allow for behavioral economic assessment of that drug's intensity of demand (preferred level of consumption at extremely low prices) and demand elasticity (sensitivity of consumption to price), among other metrics. However, a purchasing task for cocaine in cocaine-dependent individuals has not been investigated. This study examined a novel Cocaine Purchasing Task and the relation between resulting demand metrics and self-reported cocaine use data. Participants completed a questionnaire assessing hypothetical purchases of cocaine units at prices ranging from $0.01 to $1,000. Demand curves were generated from responses on the Cocaine Purchasing Task. Correlations compared metrics from the demand curve to measures of real-world cocaine use. Group and individual data were well modeled by a demand curve function. The validity of the Cocaine Purchasing Task was supported by a significant correlation between the demand curve metrics of demand intensity and O max (determined from Cocaine Purchasing Task data) and self-reported measures of cocaine use. Partial correlations revealed that after controlling for demand intensity, demand elasticity and the related measure, P max, were significantly correlated with real-world cocaine use. Results indicate that the Cocaine Purchasing Task produces orderly demand curve data, and that these data relate to real-world measures of cocaine use.
Demand Curves for Hypothetical Cocaine in Cocaine-Dependent Individuals
Bruner, Natalie R.; Johnson, Matthew W.
2013-01-01
Rationale Drug purchasing tasks have been successfully used to examine demand for hypothetical consumption of abused drugs including heroin, nicotine, and alcohol. In these tasks drug users make hypothetical choices whether to buy drugs, and if so, at what quantity, at various potential prices. These tasks allow for behavioral economic assessment of that drug's intensity of demand (preferred level of consumption at extremely low prices) and demand elasticity (sensitivity of consumption to price), among other metrics. However, a purchasing task for cocaine in cocaine-dependent individuals has not been investigated. Objectives This study examined a novel Cocaine Purchasing Task and the relation between resulting demand metrics and self-reported cocaine use data. Methods Participants completed a questionnaire assessing hypothetical purchases of cocaine units at prices ranging from $0.01 to $1,000. Demand curves were generated from responses on the Cocaine Purchasing Task. Correlations compared metrics from the demand curve to measures of real-world cocaine use. Results Group and individual data were well modeled by a demand curve function. The validity of the Cocaine Purchasing Task was supported by a significant correlation between the demand curve metrics of demand intensity and Omax (determined from Cocaine Purchasing Task data) and self-reported measures of cocaine use. Partial correlations revealed that after controlling for demand intensity, demand elasticity and the related measure, Pmax, were significantly correlated with real-world cocaine use. Conclusions Results indicate that the Cocaine Purchasing Task produces orderly demand curve data, and that these data relate to real-world measures of cocaine use. PMID:24217899
Effectiveness of second-line antiretroviral therapy: the impact of drug switches.
Braga, Letícia Penna; Mendicino, Cássia Cristina Pinto; Reis, Edna Afonso; Carmo, Ricardo Andrade; Menezes de Pádua, Cristiane Aparecida
2017-12-01
Including antiretroviral drug switches as a measure of ART failure could be more suitable than conventional measures to evaluate health outcomes in "real-world" settings. This is part of a historical cohort of HIV-infected adults who initiated ART from 2001-2005, and were followed up for a maximum of five years in three HIV/AIDS centers in Belo Horizonte, Brazil. Follow-up information included data from 2001-2010. All patients switched from first-line ART were included. Second-line ART effectiveness was measured as the time-to-ART failure. Failure was defined simulating two scenarios: (1) Clinical, immunological and virological failure (scenario 1); and scenario 1 plus ART switches (scenario 2). Descriptive analysis, Kaplan-Meier curves, log-rank test, and Cox proportional hazards model were performed. We identified 119 eligible patients; most had protease inhibitor (PI)-based regimens prescribed as second-line. The incidence of failure was different for the two scenarios (29.4% vs. 54.6% for scenario 1 and 2, respectively; p impact of ART switches in representing lack of ART effectiveness.
DEFF Research Database (Denmark)
Kyndi, M.; Sorensen, F.B.; Overgaard, M.
2008-01-01
b&c trials, were IHC stained for ER, PgR and HER2. In addition, ER and PgR were measured in the DBCG82 b&c trials by a biochemical analysis. Statistical analyses included Kappa statistics, Kaplan-Meier survival curves, Log-rank tests, and Cox regression hazards analyses. Results and conclusion. IHC...... cores and biochemical analyses. Patients and methods. A central and a peripheral 1mm core and a whole section from each of 54 paraffin blocks from 27 breast cancers included in a one-institution cohort, and a single 1 min central TMA core, from each breast tumor from 1000 patients included in the DBCG82...... IHC stainings of TMA cores and biochemical analyses. Divergence between IHC and biochemical analyses was predominantly due to the chosen thresholds. IHC staining of one 1mm core from each tumor revealed a significant independent prognostic value of PgR and HER2 on overall survival. In conclusion, IHC...
DEFF Research Database (Denmark)
Kyndi, Marianne; Sørensen, Flemming Brandt; Knudsen, H
2008-01-01
&c trials, were IHC stained for ER, PgR and HER2. In addition, ER and PgR were measured in the DBCG82 b&c trials by a biochemical analysis. Statistical analyses included Kappa statistics, Kaplan-Meier survival curves, Log-rank tests, and Cox regression hazards analyses. RESULTS AND CONCLUSION: IHC stainings...... cores and biochemical analyses. PATIENTS AND METHODS: A central and a peripheral 1mm core and a whole section from each of 54 paraffin blocks from 27 breast cancers included in a one-institution cohort, and a single 1mm central TMA core, from each breast tumor from 1000 patients included in the DBCG82 b...... stainings of TMA cores and biochemical analyses. Divergence between IHC and biochemical analyses was predominantly due to the chosen thresholds. IHC staining of one 1mm core from each tumor revealed a significant independent prognostic value of PgR and HER2 on overall survival. In conclusion, IHC stainings...
Liu, Xueyou; Xu, Jianguo; Mao, Ke; Wang, Mengmeng; Ren, Peng; Lei, Ding; Fang, Yuan; Chen, Wenjing; Mao, Boyong; Zhou, Dong; Li, Jinmei; Hong, Zhen; Yan, Bo; An, Dongmei; Liu, Ling; Chen, Jiani; Luo, Rong; Zhou, Hui; Yu, Tao; Zhang, Heng
2018-04-01
To evaluate the potential risk factors associated with seizure recurrence in different periods after epilepsy surgery. A total of 303 patients with refractory epilepsy after epilepsy surgery were included. The Kaplan-Meier method with log-rank test and univariate and multivariate Cox proportional hazards model were performed to calculate the comparison of survival curves between groups and identify the risk factors associated with seizure recurrence in different periods after surgery. The significant predictors of seizure recurrence were determined, including duration of epilepsy (P = 0.018), seizure types (P = 0.009), magnetic resonance imaging findings (P = 0.007), intracranial electroencephalographic recordings (P = 0.002), sides of epileptogenic zone (P = 0.025), and types of surgery (P = 0.002). Moreover, the significant predictors of seizure recurrence within 12 months after surgery were also included, such as gender (P = 0.007), duration of epilepsy (P = 0.013), intracranial electroencephalographic recordings (P = 0.003), and types of surgery (P 36 months after surgery. We reconfirmed the well-known risk factors associated with seizure recurrence and also identified the controversial variables. In addition, we found that the risk factors associated with seizure recurrence were different in different periods after epilepsy surgery. Copyright © 2018 Elsevier Inc. All rights reserved.
Increased Persistence of Initial Treatment for HIV Infection With Modern Antiretroviral Therapy.
Davy-Mendez, Thibaut; Eron, Joseph J; Zakharova, Oksana; Wohl, David A; Napravnik, Sonia
2017-10-01
Initiating antiretroviral therapy (ART) early improves clinical outcomes and prevents transmission. Guidelines for first-line therapy have changed with the availability of newer ART agents. In this study, we compared persistence and virologic responses with initial ART according to the class of anchor agent used. An observational clinical cohort study in the Southeastern United States. All HIV-infected patients participating in the UNC Center for AIDS Research Clinical Cohort (UCHCC) and initiating ART between 1996 and 2014 were included. Separate time-to-event analyses with regimen discontinuation and virologic failure as outcomes were used, including Kaplan-Meier survival curves and adjusted Cox proportional hazards models. One thousand six hundred twenty-four patients were included (median age of 37 years at baseline, 28% women, 60% African American, and 28% white). Eleven percent initiated integrase strand transfer inhibitor (INSTI), 33% non-nucleoside reverse transcriptase inhibitor (NNRTI), 20% boosted protease inhibitor, 27% other, and 9% NRTI only regimens. Compared with NNRTI-containing regimens, INSTI-containing regimens had an adjusted hazard ratio of 0.49 (95% confidence interval, 0.35 to 0.69) for discontinuation and 0.70 (95% confidence interval, 0.46 to 1.06) for virologic failure. All other regimen types were associated with increased rates of discontinuation and failure compared with NNRTI. Initiating ART with an INSTI-containing regimen was associated with lower rates of regimen discontinuation and virologic failure.
POSSIBLE RECESSION CURVE APPLICATIONS FOR RETENTION EVALUATION
Directory of Open Access Journals (Sweden)
Daniel Liberacki
2015-11-01
Full Text Available The objective of the article was to present possible applications of recession flow curve in a small lowland watershed retention discharge size evaluation. The examined woodland micro catchment area of 0.52 sq km is located in Puszcza Zielonka in central Wielkopolska. The Hutka catchment is typically woody with high retention abilities. The catchment of the Hutka watercourse is forested in 89%, the other 11% is covered by swamps and wasteland. The predominant sites are fresh mixed coniferous forest (BMśw, fresh coniferous forest (Bśw and alder carr forest (Ol. Landscape in catchment is characterized by a large number of interior depressions, filled partly with rainwater or peatbogs, with poorly developed natural drainage. The watercourses do not exceed 1 km in length, the mean width is approx. 0.5 m, while mean depth ranges from 0.2 to 0.3 m. During hydrological research conducted in 1997/1998–1999/2000, 35 major (characteristic raised water stages were observed in Hutka after substantial precipitation. The recession curve dating from 18–24 September 2000 has the α and n rates nearest to average. Comparing the model curve and the curve created by observing watercourse flow, one can notice their resemblance and that they have similar ordinate values as well as shape. In the case of other recession curves, the maximum differences of ordinate values are also about 0.1–0.2 l/s/km2. The measuured α and n rates do not reveal any regularities. There are no significant statistical Horton model parameter (for recession flow curves dependencies between α and n and e.g. initial flows (Qo or the whole period of high water waves (Qp. Consequently, calculated relation between these parameters is only an approximation for the general evaluation of the retention discharge in the catchment area towards retention with flow function.
From Curve Fitting to Machine Learning
Zielesny, Achim
2011-01-01
The analysis of experimental data is at heart of science from its beginnings. But it was the advent of digital computers that allowed the execution of highly non-linear and increasingly complex data analysis procedures - methods that were completely unfeasible before. Non-linear curve fitting, clustering and machine learning belong to these modern techniques which are a further step towards computational intelligence. The goal of this book is to provide an interactive and illustrative guide to these topics. It concentrates on the road from two dimensional curve fitting to multidimensional clus
Computer Controlled Photometer/Planck Curve Experiment
Dupuy, David L.; Peters, Philip B.
2001-11-01
Developed as a demo in our course for computer control of laboratory experiments, this experiment had two goals: to attempt to measure the output of a tungsten bulb over a wide range of wavelengths, and to test the use of LabVIEW as a programming language for teaching experiment control. The brightness readings were corrected for instrumental effects and fitted with a Planck curve. The experiment involved digital input, digital output to a microstepper controller to move the filter wheel, and analog input. Results will be shown for the Planck curve and the LabVIEW program.
Phonon dispersion curves for CsCN
International Nuclear Information System (INIS)
Gaur, N.K.; Singh, Preeti; Rini, E.G.; Galgale, Jyostna; Singh, R.K.
2004-01-01
The motivation for the present work was gained from the recent publication on phonon dispersion curves (PDCs) of CsCN from the neutron scattering technique. We have applied the extended three-body force shell model (ETSM) by incorporating the effect of coupling between the translation modes and the orientation of cyanide molecules for the description of phonon dispersion curves of CsCN between the temperatures 195 and 295 K. Our results on PDCs in symmetric direction are in good agreement with the experimental data measured with inelastic neutron scattering technique. (author)
Angles between Curves in Metric Measure Spaces
Directory of Open Access Journals (Sweden)
Han Bang-Xian
2017-09-01
Full Text Available The goal of the paper is to study the angle between two curves in the framework of metric (and metric measure spaces. More precisely, we give a new notion of angle between two curves in a metric space. Such a notion has a natural interplay with optimal transportation and is particularly well suited for metric measure spaces satisfying the curvature-dimension condition. Indeed one of the main results is the validity of the cosine formula on RCD*(K, N metric measure spaces. As a consequence, the new introduced notions are compatible with the corresponding classical ones for Riemannian manifolds, Ricci limit spaces and Alexandrov spaces.
Migration and the Wage-Settings Curve
DEFF Research Database (Denmark)
Brücker, Herbert; Jahn, Elke
Germany on basis of a wage-setting curve. The wage-setting curve relies on the assumption that wages respond to a hange in the unemployment rate, albeit imperfectly. This allows one to derive the wage and employment effects of migration simultaneously in a general equilibrium framework. Using...... in the German labor force through immigration increases the aggregate unemployment rate by less than 0.1 percentage points and reduces average wages by 0.1 percent in the short run. While native workers benefit from increased wages and lower unemployment, foreign workers are adversely affected....
Bound states in curved quantum waveguides
International Nuclear Information System (INIS)
Exner, P.; Seba, P.
1987-01-01
We study free quantum particle living on a curved planar strip Ω of a fixed width d with Dirichlet boundary conditions. It can serve as a model for electrons in thin films on a cylindrical-type substrate, or in a curved quantum wire. Assuming that the boundary of Ω is infinitely smooth and its curvature decays fast enough at infinity, we prove that a bound state with energy below the first transversal mode exists for all sufficiently small d. A lower bound on the critical width is obtained using the Birman-Schwinger technique. (orig.)
Boiling curve in high quality flow boiling
International Nuclear Information System (INIS)
Shiralkar, B.S.; Hein, R.A.; Yadigaroglu, G.
1980-01-01
The post dry-out heat transfer regime of the flow boiling curve was investigated experimentally for high pressure water at high qualities. The test section was a short round tube located downstream of a hot patch created by a temperature controlled segment of tubing. Results from the experiment showed that the distance from the dryout point has a significant effect on the downstream temperatures and there was no unique boiling curve. The heat transfer coefficients measured sufficiently downstream of the dryout point could be correlated using the Heineman correlation for superheated steam, indicating that the droplet deposition effects could be neglected in this region
Light Curve Analysis of SAO23229
Directory of Open Access Journals (Sweden)
Ho-Il Kim
1993-06-01
Full Text Available We have made UBV light curves of a newly discovered eclipsing binary, SAO23229 at Sobaeksan Astronomy Observatory. We determined a minimum light time of HJD2448636.1170+/-0.0005 that is 3 minutes later than predicted time, and founda peculiar light variation at phase 0.75 that may not be secondary eclipse. Orbital period of SAO23229 would be 4.2 days rather than 2.1 days. Our analysis of the light curves shows that SAO23229 has a detached configuration consisting of two almost identical F type main sequence stars.
Analysis of characteristic performance curves in radiodiagnosis by an observer
International Nuclear Information System (INIS)
Kossovoj, A.L.
1988-01-01
Methods and ways of construction of performance characteristic curves (PX-curves) in roentgenology, their qualitative and quantitative estimation are described. Estimation of PX curves application for analysis of scintigraphic and sonographic images is presented
Higher rank BN-theory for curves of genus 4
Lange, H.; Newstead, P. E.
2015-01-01
Higher rank Brill-Noether theory is completely known for curves of genus $\\leq 3$. In this paper, we investigate the theory for curves of genus 4. Some of our results apply to curves of arbitrary genus.
Bijlsma, S.; Boelens, H. F. M.; Hoefsloot, H. C. J.; Smilde, A. K.
2000-01-01
A traditional curve fitting (TCF) algorithm is compared with a classical curve resolution (CCR) approach for estimating reaction rate constants from spectral data obtained in time of a chemical reaction. In the TCF algorithm, reaction rate constants an estimated from the absorbance versus time data
Characterization of Elliptic Curve Traces under FR-reduction
Miyaji, Atsuko; Nakabayashi, Masaki; Takano, Shunzo
2001-01-01
Elliptic curve cryptosystems([19],[25]) are based on the elliptic curve discrete logarithm problem(ECDLP). If elliptic curve cryptosystems avoid FR-reduction([11],[17]) and anomalous elliptic curve over F_q ([34],[3],[36]), then with current knowledge we can construct elliptic curve cryptosystems over a smaller definition field. ECDLP has an interesting property that the security deeply depends on elliptic curve traces rather than definition fields, which does not occur in the case of the dis...
Modeling survival: application of the Andersen-Gill model to Yellowstone grizzly bears
Johnson, Christopher J.; Boyce, Mark S.; Schwartz, Charles C.; Haroldson, Mark A.
2004-01-01
Wildlife ecologists often use the Kaplan-Meier procedure or Cox proportional hazards model to estimate survival rates, distributions, and magnitude of risk factors. The Andersen-Gill formulation (A-G) of the Cox proportional hazards model has seen limited application to mark-resight data but has a number of advantages, including the ability to accommodate left-censored data, time-varying covariates, multiple events, and discontinuous intervals of risks. We introduce the A-G model including structure of data, interpretation of results, and assessment of assumptions. We then apply the model to 22 years of radiotelemetry data for grizzly bears (Ursus arctos) of the Greater Yellowstone Grizzly Bear Recovery Zone in Montana, Idaho, and Wyoming, USA. We used Akaike's Information Criterion (AICc) and multi-model inference to assess a number of potentially useful predictive models relative to explanatory covariates for demography, human disturbance, and habitat. Using the most parsimonious models, we generated risk ratios, hypothetical survival curves, and a map of the spatial distribution of high-risk areas across the recovery zone. Our results were in agreement with past studies of mortality factors for Yellowstone grizzly bears. Holding other covariates constant, mortality was highest for bears that were subjected to repeated management actions and inhabited areas with high road densities outside Yellowstone National Park. Hazard models developed with covariates descriptive of foraging habitats were not the most parsimonious, but they suggested that high-elevation areas offered lower risks of mortality when compared to agricultural areas.
Directory of Open Access Journals (Sweden)
R.S. Horta
Full Text Available ABSTRACT In spite of the many available protocols, the use of chemotherapy for the management of canine mast cell tumours (MCT remains empirical, and there is lack of criteria for the choice of protocol and definition of patients who may benefit from treatment. The objective of this study was to evaluate the outcome of dogs with MCT after adjuvant chemotherapy according to the risk of recurrence or metastasis proposed on the literature. This prospective study included 89 followed up dogs with prognosis assesment including clinical, histological, immunohistochemical and genetic features of canine MCT. Patients were grouped according to risk of recurrence and metastasis and recommended treatment with lomustine followed by chlorambucil if considered at high-risk, or vinblastine followed by chlorambucil if a patient was at intermediate risk. Outcome was defined by disease-free interval (DFI and overall survival (OS estimated by Kaplan-Meier curve. Adjuvant lomustine was useful for control of canine MCT of high-risk of recurrence or metastasis, but only when sequentially associated to chlorambucil with a DFI of 686 days and not reached OS. There was no difference in outcome in the intermediate-risk group despite choosen treatment. Patients at intermediate-to-low risk may not require adjuvant treatments, even in the absence of free surgical margins.
Park, Silvia; Kim, Kihyun; Jang, Jun Ho; Kim, Seok Jin; Kim, Won Seog; Kang, Eun-Suk; Jung, Chul Won
2015-09-01
Receptors on natural killer (NK) cells, named killer immunoglobulin-like receptors (KIRs), recognize HLA class I alleles. Patients (n=59) who received allogeneic hematopoietic stem cell transplantation (HSCT) from either a related (n=17) or unrelated donor (n=42) in Samsung Medical Center (Seoul, South Korea) were included. KIR mismatch was defined as incompatibility between the donor KIR and recipient KIR ligand (receptor-ligand model), and all cases were classified into the two broad haplotypes of KIR A and B. Patients with acute leukemia (n=51, 86.4%) or myelodysplastic syndrome (n=8, 13.6%) were included. Peripheral blood was used as the source of stem cells in all patients. Kaplan-Meier survival curves for overall survival (OS), disease-free survival (DFS), and cumulative incidence of relapse (CIR) favored recipients with a KIR-mismatched donor, although the differences were not statistically significant. In multivariate analysis, KIR mismatch was an independent prognostic indicator of a better OS (P=0.010, HR=0.148, 95% CI 0.034-0.639), DFS (P=0.022, HR=0.237, 95% CI 0.069-0.815), and CIR (P=0.031, HR=0.117, 95% CI 0.017-0.823). OS, DFS, and CIR did not differ significantly between the KIR A and B haplotypes. Copyright © 2015. Published by Elsevier Inc.
Macon, Céline; Carrier, Hélène; Janczewski, Aurélie; Verger, Pierre; Casanova, Ludovic
2018-01-01
The accessibility of ophthalmologists appears to influence the quality of screening for diabetic retinopathy (DR). The principal objective of this study was to analyze the effect of automobile travel time to the closest ophthalmologist on the time to DR screening. This historical cohort study used reimbursement databases from the principal national health insurance fund. Patients were included if they had been reimbursed at least thrice for oral antidiabetic medications in the 12 months before the study start date. Patients were followed up from January 1, 2008, for 4 years. The expected event was a DR screening by an ocular fundus examination. The automobile travel time to the nearest ophthalmologist was calculated by the distance between communes, estimated by appropriate software. A Kaplan-Meier curve and a multivariate Cox model were used to model the effect of travel time on the time until DR screening. A sensitivity analysis of travel time described the results of the Cox model. At the start of 2008, 6,573 patients living in 328 different municipalities were included. The multivariate model found that patients living 60 min or more away from an ophthalmologist had a lower instantaneous probability of DR screening than those living travel time. Increased automobile travel time for patients with diabetes to the nearest ophthalmologist was associated with a longer time to DR screening.
Giri, Smith; Shrestha, Rajesh; Pathak, Ranjan; Bhatt, Vijaya Raj
2015-08-01
Several studies have reported excellent long-term overall survival (OS) of patients with hairy cell leukemia (HCL) without racial disparity. Studies in other cancers have demonstrated worse mortality among African American (AA) individuals. We used the Surveillance, Epidemiology, and End Results 18 database to identify HCL patients diagnosed between 1978 and 2011. Kaplan-Meier curves were plotted to estimate OS. Univariate analysis using the life table method and multivariate Cox regression model were used to determine the independent effect of race on OS. The study population included 78% men and had a median age of 56 years. Race included 93% white, 3.5% Asian/Pacific Islander, and 3.5% AA. The 10-year OS was significantly less for AA as compared with white and Asian/Pacific Islander individuals (54% vs. 72% vs. 75%; P population-based study, only half of AA patients but more than two-thirds of HCL patients from other racial groups were alive at 10 years. Such drastic racial differences in OS of HCL patients at the population level mandates further evaluation of the contributory biological, socioeconomic, health system, and other factors. Understanding and overcoming such racial disparities might close the racial differences in OS of this potentially curable disease. Copyright © 2015 Elsevier Inc. All rights reserved.
The thermoluminescent curve as parameter to compare archaeological ceramics
International Nuclear Information System (INIS)
Dominguez R, I.R.; Ramirez C, G.A.; Gonzalez M, P.R.; Mendoza A, D.; Martinez C, G.
2006-01-01
Most mineral materials, including the constituents of pottery, have the property of thermoluminescence (TL), where part of the energy from radioactive decay in the mineral is stored and later released as light upon strong heating. The intensity of emitted light as a function of temperature is the thermoluminescence glow curve. However, it is well-know the thermoluminescence glow curve form depends of several factors associates with the incident radiation and type of materials. Between the factors associated with the materials, it can be mentioned the quantity and type of crystalline phases, and quantity and type of impurities that they could be present in the material. That is to say, materials with different physicochemical characteristics will produce different thermoluminescence glow curve, although, they have been irradiated under the same conditions. In accordance with the above mentioned, it is possible to identified differences between pre hispanic ceramic belonging to a same site and other sites. In this work a discussion about advantages and disadvantages is presented. Some specific examples in ceramic artifacts belonging to the Matlatzinca and Teotihuacan cultures are included. (Author)
Some genus 3 curves with many points
Auer, R; Top, J; Fieker, C; Kohel, DR
2002-01-01
We explain a naive approach towards the problem of finding genus 3 curves C over any given finite field F-q of odd characteristic, with a number of rational points close to the Hasse-Weil-Serre upper bound q+1+3[2rootq]. The method turns out to be successful at least in characteristic 3.
Meromorphic connections on vector bundles over curves
Indian Academy of Sciences (India)
Descartes,. 67084 Strasbourg Cedex, France. *Correspond author. E-mail: indranil@math.tifr.res.in; heu@math.unistra.fr. MS received 17 July 2013; revised 20 October 2013. Abstract. We give a criterion for filtered vector bundles over curves to admit a ...
Phonon dispersion curves of CsCN
Indian Academy of Sciences (India)
Abstract. The motivation for the present work was gained from the recent publication on phonon dispersion curves (PDCs) of CsCN from the neutron scattering technique. We have applied the extended three-body force shell model (ETSM) by incorporating the effect of coupling between the translation modes and the ...
Replication and analysis of Ebbinghaus' forgetting curve
Murre, J.M.J.; Dros, J.
2015-01-01
We present a successful replication of Ebbinghaus’ classic forgetting curve from 1880 based on the method of savings. One subject spent 70 hours learning lists and relearning them after 20 min, 1 hour, 9 hours, 1 day, 2 days, or 31 days. The results are similar to Ebbinghaus' original data. We
Steady turbulent flow in curved rectangular channels
De Vriend, H.J.
1979-01-01
After the study of fully developed and developing steady laminar flow in curved channels of shallow rectangular wet cross-section (see earlier reports in this series), steady turbulent flow in such channels is investigated as a next step towards a mathematical model of the flow in shallow river
Developing laminar flow in curved rectangular channels
De Vriend, H.J.
1978-01-01
As an intermediate step between earlier investigations on fully developed laminar flow in curved channels of shallow rectancular wet cross-section and the mathematical modeling of turbulent flow in river bends, a mathematical model of developing laminar flow in such channels is investigated. The
Covariant quantizations in plane and curved spaces
Energy Technology Data Exchange (ETDEWEB)
Assirati, J.L.M. [University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Gitman, D.M. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); P.N. Lebedev Physical Institute, Moscow (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil)
2017-07-15
We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)
Covariant quantizations in plane and curved spaces
International Nuclear Information System (INIS)
Assirati, J.L.M.; Gitman, D.M.
2017-01-01
We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)
Designing the Alluvial Riverbeds in Curved Paths
Macura, Viliam; Škrinár, Andrej; Štefunková, Zuzana; Muchová, Zlatica; Majorošová, Martina
2017-10-01
The paper presents the method of determining the shape of the riverbed in curves of the watercourse, which is based on the method of Ikeda (1975) developed for a slightly curved path in sandy riverbed. Regulated rivers have essentially slightly and smoothly curved paths; therefore, this methodology provides the appropriate basis for river restoration. Based on the research in the experimental reach of the Holeška Brook and several alluvial mountain streams the methodology was adjusted. The method also takes into account other important characteristics of bottom material - the shape and orientation of the particles, settling velocity and drag coefficients. Thus, the method is mainly meant for the natural sand-gravel material, which is heterogeneous and the particle shape of the bottom material is very different from spherical. The calculation of the river channel in the curved path provides the basis for the design of optimal habitat, but also for the design of foundations of armouring of the bankside of the channel. The input data is adapted to the conditions of design practice.
Electronic properties of curved graphene sheets
Cortijo, Alberto; Vozmediano, Maria A. H.
2006-01-01
A model is proposed to study the electronic structure of slightly curved graphene sheets with an arbitrary number of pentagon-heptagon pairs and Stone-Wales defects based on a cosmological analogy. The disorder induced by curvature produces characteristic patterns in the local density of states that can be observed in scanning tunnel and transmission electron microscopy.
A Mean Value Formula for Elliptic Curves
Directory of Open Access Journals (Sweden)
Rongquan Feng
2014-01-01
Full Text Available It is proved in this paper that, for any point on an elliptic curve, the mean value of x-coordinates of its n-division points is the same as its x-coordinate and that of y-coordinates of its n-division points is n times that of its y-coordinate.
Bayesian Estimation of Item Response Curves.
Tsutakawa, Robert K.; Lin, Hsin Ying
1986-01-01
Item response curves for a set of binary responses are studied from a Bayesian viewpoint of estimating the item parameters. For the two-parameter logistic model with normally distributed ability, restricted bivariate beta priors are used to illustrate the computation of the posterior mode via the EM algorithm. (Author/LMO)
Numerical analysis of thermoluminescence glow curves
International Nuclear Information System (INIS)
Gomez Ros, J. M.; Delgado, A.
1989-01-01
This report presents a method for the numerical analysis of complex thermoluminescence glow curves resolving the individual glow peak components. The method employs first order kinetics analytical expressions and is based In a Marquart-Levenberg minimization procedure. A simplified version of this method for thermoluminescence dosimetry (TLD) is also described and specifically developed to operate whit Lithium Fluoride TLD-100. (Author). 36 refs
Tempo curves considered harmful (part 2)
Desain, P.; Honing, H.
1991-01-01
A column (the second of a series of three) constitutes an abridged and adapted version of Tempo curves considered harmful . M (an amateur mathematician) and P (a would-be psychologist) incorporated some generative models for expressive timing in their sequencer program. This proved partially
Morphological modelling of strongly curved islands
Roelvink, D.; Den Heijer, C.; Van Thiel De Vries, J.S.M.
2013-01-01
Land reclamations and island coasts often involve strongly curved shorelines, which are challenging to be properly modeled by numerical morphological models. Evaluation of the long term development of these types of coasts as well as their response to storm conditions requires proper representation
Spherical images and inextensible curved folding
Seffen, Keith A.
2018-02-01
In their study, Duncan and Duncan [Proc. R. Soc. London A 383, 191 (1982), 10.1098/rspa.1982.0126] calculate the shape of an inextensible surface folded in two about a general curve. They find the analytical relationships between pairs of generators linked across the fold curve, the shape of the original path, and the fold angle variation along it. They present two special cases of generator layouts for which the fold angle is uniform or the folded curve remains planar, for simplifying practical folding in sheet-metal processes. We verify their special cases by a graphical treatment according to a method of Gauss. We replace the fold curve by a piecewise linear path, which connects vertices of intersecting pairs of hinge lines. Inspired by the d-cone analysis by Farmer and Calladine [Int. J. Mech. Sci. 47, 509 (2005), 10.1016/j.ijmecsci.2005.02.013], we construct the spherical images for developable folding of successive vertices: the operating conditions of the special cases in Duncan and Duncan are then revealed straightforwardly by the geometric relationships between the images. Our approach may be used to synthesize folding patterns for novel deployable and shape-changing surfaces without need of complex calculation.
Electron conductance in curved quantum structures
DEFF Research Database (Denmark)
Willatzen, Morten; Gravesen, Jens
2010-01-01
A differential-geometry analysis is employed to investigate the transmission of electrons through a curved quantum-wire structure. Although the problem is a three-dimensional spatial problem, the Schrodinger equation can be separated into three general coordinates. Hence, the proposed method...
Principal normal indicatrices of closed space curves
DEFF Research Database (Denmark)
Røgen, Peter
1999-01-01
A theorem due to J. Weiner, which is also proven by B. Solomon, implies that a principal normal indicatrix of a closed space curve with nonvanishing curvature has integrated geodesic curvature zero and contains no subarc with integrated geodesic curvature pi. We prove that the inverse problem alw...
Yield stress independent column buckling curves
DEFF Research Database (Denmark)
Stan, Tudor‐Cristian; Jönsson, Jeppe
2017-01-01
Using GMNIA and shell finite element modelling of steel columns it is ascertained that the buckling curves for given imperfections and residual stresses are not only dependent on the relative slenderness ratio and the cross section shape but also on the magnitude of the yield stress. The influence...
Theoretical Magnon Dispersion Curves for Gd
DEFF Research Database (Denmark)
Lindgård, Per-Anker; Harmon, B. N.; Freeman, A. J.
1975-01-01
The magnon dispersion curve of Gd metal has been determined from first principles by use of augmented-plane-wave energy bands and wave functions. The exchange matrix elements I(k⃗, k⃗′) between the 4f electrons and the conduction electrons from the first six energy bands were calculated under...
ATLAS detector records its first curved muon
2007-01-01
The barrel muon spectrometer of the ATLAS detector has acquired its first cosmic event in a magnetic field produced by the barrel toroid magnet. This was an important test of the chambers in their final configurations, and marked the first triggering and measurement of curved cosmic ray muons in ATLAS.
Discrete groups, Mumford curves and Theta functions
Put, Marius van der
1992-01-01
A discrete group Γ given over some complete non archimedean valued field defines a curve X. The theta functions for Γ provide an analytic construction for the Jacobian variety of X. A theory of theta functions is developed with the help of currents on trees and graphs and the cohomology for Γ. In
Comparison and evaluation of mathematical lactation curve ...
African Journals Online (AJOL)
Using the General Linear Model procedure in SAS, the effect of herd, calving year, age at calving, season of production, age and days in milk were found to be significant on daily milk yield. The suitability of seven mathematical models (with three, four and five parameters) for describing the 305-day milk yield lactation curve ...
Affine LIBOR Models with Multiple Curves
DEFF Research Database (Denmark)
Grbac, Zorana; Papapantoleon, Antonis; Schoenmakers, John
2015-01-01
We introduce a multiple curve framework that combines tractable dynamics and semianalytic pricing formulas with positive interest rates and basis spreads. Negative rates and positive spreads can also be accommodated in this framework. The dynamics of overnight indexed swap and LIBOR rates...
Measuring Systematic Error with Curve Fits
Rupright, Mark E.
2011-01-01
Systematic errors are often unavoidable in the introductory physics laboratory. As has been demonstrated in many papers in this journal, such errors can present a fundamental problem for data analysis, particularly when comparing the data to a given model. In this paper I give three examples in which my students use popular curve-fitting software…
Principal G-bundles on nodal curves
Indian Academy of Sciences (India)
Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45
If Y is reducible these notions depend on parameters a = (a1,...,aI ). The study of G-bundles on Y is done by extending the notion of (generalized) parabolic vector bundles [U1] to generalized parabolic principal G-bundles (called GPGs in short) on the curve C and using the correspondence between them and principal ...
Principal normal indicatrices of closed space curves
DEFF Research Database (Denmark)
Røgen, Peter
1997-01-01
A theorem due to J. Weiner, which also is proven by B. Solomon, implies that a principal normal indicatrix of a closed space curve with non-vanishing curvature has integrated geodesic curvature zero and contains no sub arc with integrated geodesic curvature Pi. We prove that the inverse problem...
Tropical count of curves on abelian varieties
DEFF Research Database (Denmark)
Halle, Lars Halvard; Rose, Simon Charles Florian
2017-01-01
We investigate the problem of counting tropical genus g curves ing-dimensional tropical abelian varieties. We do this by studyingmaps from principally polarized tropical abelian varieties into afixed abelian variety. For g = 2, 3, we prove that the tropical countmatches the count provided in [Göt98...
Remote sensing used for power curves
DEFF Research Database (Denmark)
Wagner, Rozenn; Ejsing Jørgensen, Hans; Schmidt Paulsen, Uwe
2008-01-01
Power curve measurement for large wind turbines requires taking into account more parameters than only the wind speed at hub height. Based on results from aerodynamic simulations, an equivalent wind speed taking the wind shear into account was defined and found to reduce the power standard deviat...
Tempo curves considered harmful (part 1)
Desain, P.; Honing, H.
1991-01-01
A column (the first of a series of three) constitutes an abridged and adapted version of Tempo curves considered harmful . Two friends, an amateur mathematician (M) and a would-be psychologist (P), invited a retired pianist to do some experiments with their new sequencer program. As musical material
Intelligence, genes, and success scientists respond to the bell curve
Fienberg, Stephen; Resnick, Daniel; Roeder, Kathryn
1997-01-01
This is author-approved bcc. If it is too long, delete the last sentence in each of the biographies. THE BELL CURVE by Richard Herrnstein and Charles Murray, a best selling book published in 1994, set off a hailstorm of controversy about the relationships among IQ, genetics, and various social outcomes, including welfare dependency, crime, and earnings. Much of the public reaction to the book was polemical and did not focus on the details of the science and in particular on the validity of the statistical arguments that underlie the books's conclusions. A detailed understanding of the arguments in THE BELL CURVE requires knowledge about (i) statistical models for genetic heritability, (ii) factor analysis, especially as it has been applied to the analysis of IQ tests, (iii) logistic regression and multiple regression analyses,and (iv) causal modelling and alternative statistical frameworks for making inference from longitudinal data. In this volume a group of statisticians and social scientists have assembled...
The Phillips Curve for the Romanian Economy, 1992-2017
Directory of Open Access Journals (Sweden)
Dorin Jula
2017-06-01
Full Text Available The paper analyses the relationship between the unemployment rate and inflation, in Romania, during the 1992 – 1997 (March period. For this purpose, we have estimated two econometric models, where the inflation trend has considered as a benchmark for inflation dynamics and the unemployment gap was built after applying the Hodrick-Prescott (HP filter at unemployment rate. We have found that the unemployment gap had the greatest relevance in inflation model if we have taken a four months delay. The data support the hypothesis of a significant relationship between inflation and unemployment, with the shape described by the Phillips curve, namely the coefficients of unemployment gap were negative, econometrically significant and comparable as dimension in both models of inflation dynamics. We have calculated that the coefficient of unemployment gap is -0.344 in the Phillips curve model where the errors follow an ARMA(2, 2 process and -0.386 in the model which includes the inflation inertia.
Feature curve extraction from point clouds via developable strip intersection
Directory of Open Access Journals (Sweden)
Kai Wah Lee
2016-04-01
Full Text Available In this paper, we study the problem of computing smooth feature curves from CAD type point clouds models. The proposed method reconstructs feature curves from the intersections of developable strip pairs which approximate the regions along both sides of the features. The generation of developable surfaces is based on a linear approximation of the given point cloud through a variational shape approximation approach. A line segment sequencing algorithm is proposed for collecting feature line segments into different feature sequences as well as sequential groups of data points. A developable surface approximation procedure is employed to refine incident approximation planes of data points into developable strips. Some experimental results are included to demonstrate the performance of the proposed method.
Ko, William L.; Fleischer, Van Tran
2011-01-01
The Ko displacement theory originally developed for shape predictions of straight beams is extended to shape predictions of curved beams. The surface strains needed for shape predictions were analytically generated from finite-element nodal stress outputs. With the aid of finite-element displacement outputs, mathematical functional forms for curvature-effect correction terms are established and incorporated into straight-beam deflection equations for shape predictions of both cantilever and two-point supported curved beams. The newly established deflection equations for cantilever curved beams could provide quite accurate shape predictions for different cantilever curved beams, including the quarter-circle cantilever beam. Furthermore, the newly formulated deflection equations for two-point supported curved beams could provide accurate shape predictions for a range of two-point supported curved beams, including the full-circular ring. Accuracy of the newly developed curved-beam deflection equations is validated through shape prediction analysis of curved beams embedded in the windward shallow spherical shell of a generic crew exploration vehicle. A single-point collocation method for optimization of shape predictions is discussed in detail
Curved bones: An adaptation to habitual loading.
Milne, Nick
2016-10-21
Why are long bones curved? It has long been considered a paradox that many long bones supporting mammalian bodies are curved, since this curvature results in the bone undergoing greater bending, with higher strains and so greater fracture risk under load. This study develops a theoretical model wherein the curvature is a response to bending strains imposed by the requirements of locomotion. In particular the radioulna of obligate quadrupeds is a lever operated by the triceps muscle, and the bending strains induced by the triceps muscle counter the bending resulting from longitudinal loads acting on the curved bone. Indeed the theoretical model reverses this logic and suggests that the curvature is itself a response to the predictable bending strains induced by the triceps muscle. This, in turn, results in anatomical arrangements of bone, muscle and tendon that create a simple physiological mechanism whereby the bone can resist the bending due to the action of triceps in supporting and moving the body. The model is illustrated by contrasting the behaviour of a finite element model of a llama radioulna to that of a straightened version of the same bone. The results show that longitudinal and flexor muscle forces produce bending strains that effectively counter strains due to the pull of the triceps muscle in the curved but not in the straightened model. It is concluded that the curvature of these and other curved bones adds resilience to the skeleton by acting as pre-stressed beams or strainable pre-buckled struts. It is also proposed that the cranial bending strains that result from triceps, acting on the lever that is the radioulna, can explain the development of the curvature of such bones. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.
CRITICAL CURVES AND CAUSTICS OF TRIPLE-LENS MODELS
International Nuclear Information System (INIS)
Daněk, Kamil; Heyrovský, David
2015-01-01
Among the 25 planetary systems detected up to now by gravitational microlensing, there are two cases of a star with two planets, and two cases of a binary star with a planet. Other, yet undetected types of triple lenses include triple stars or stars with a planet with a moon. The analysis and interpretation of such events is hindered by the lack of understanding of essential characteristics of triple lenses, such as their critical curves and caustics. We present here analytical and numerical methods for mapping the critical-curve topology and caustic cusp number in the parameter space of n-point-mass lenses. We apply the methods to the analysis of four symmetric triple-lens models, and obtain altogether 9 different critical-curve topologies and 32 caustic structures. While these results include various generic types, they represent just a subset of all possible triple-lens critical curves and caustics. Using the analyzed models, we demonstrate interesting features of triple lenses that do not occur in two-point-mass lenses. We show an example of a lens that cannot be described by the Chang–Refsdal model in the wide limit. In the close limit we demonstrate unusual structures of primary and secondary caustic loops, and explain the conditions for their occurrence. In the planetary limit we find that the presence of a planet may lead to a whole sequence of additional caustic metamorphoses. We show that a pair of planets may change the structure of the primary caustic even when placed far from their resonant position at the Einstein radius
Intonation and Duration Curve in Persian Interrogative Sentences
Directory of Open Access Journals (Sweden)
Mohammad Reza Keyhani
2012-03-01
Full Text Available Background and Aim: prosody is a very important factor in communication and includes such parameters as: duration, intonation, pitch, stress, rhythm etc. Intonation is the pitch variation in one sentence. Duration is the time taken to utter a voice. The aim of the present study was to evaluate some parameters of prosody such as duration and intonation curve in interrogative sentences among normal Farsi speaking adults in order to determine the characteristics of this aspect of language with an emphasis on laboratory testing.Methods: This study was performed as a cross-sectional one. The participants included 134 male and female Farsi speaking individuals aging between 18-30 years. In this study two interrogative sentences with open and closed answers were used. The voice samples were analyzed by Dr.speech -real analysis software. Data analysis incorporated unilateral analysis of variance and an intonation curve was drawn for each sentence.Results: The parameter of duration among men and women was significantly different (p≤0.001. Duration in open questions was significantly longer than yes/no questions (p≤0.001. The intonation curve of the two groups were similar.Conclusion: Men and women use duration changes, for making difference in prosody. On the whole, duration among women is longer than men. In open questions, the duration of sentences is mostly due to the question word. The intonation curve in open questions has more amplitude. Women show much more changes in basic frequency for transferring interrogative state in their expressions.
Design curves for optimizing stability of herringbone-grooved journal bearings
Fleming, D. P.; Hamrock, B. J.
1973-01-01
Curves span wide range of operating conditions, including: lubricant compressibility numbers from 0 to 80, bearing length-to-diameter ratios from 1/4 to 2, and either rotating or stationary grooved members.
Improved survival in HIV treatment programs in Asia
De La Mata, Nicole L; Kumarasamy, Nagalingeswaran; Khol, Vohith; Ng, Oon Tek; Van Nguyen, Kinh; Merati, Tuti Parwati; Pham, Thuy Thanh; Lee, Man Po; Durier, Nicolas; Law, Matthew
2016-01-01
Background Antiretroviral treatment (ART) for HIV-positive patients has expanded rapidly in Asia over the last ten years. Our study aimed to describe the time trends and risk factors for overall survival in patients receiving first-line ART in Asia. Methods We included HIV-positive adult patients who initiated ART between 2003–2013 (n=16 546), from seven sites across six Asia-Pacific countries. Patient follow-up was to May 2014. We compared survival for each country and overall by time period of ART initiation using Kaplan-Meier curves. Factors associated with mortality were assessed using Cox regression, stratified by site. We also summarized first-line ART regimens, CD4 count at ART initiation, and CD4 and HIV viral load testing frequencies. Results There were 880 deaths observed over 54 532 person-years of follow-up, a crude rate of 1.61 (1.51, 1.72) per 100 person-years. Survival significantly improved in more recent years of ART initiation. The survival probabilities at 4 years follow-up for those initiating ART in 2003–05 was 92.1%, 2006–09 was 94.3% and 2010–2013 was 94.5% (pAsia have improved survival in more recent years of ART initiation. This is likely a consequence of improvements in treatment and, patient management and monitoring over time. PMID:26961354
Kaye, B M; Borgeat, K; Mõtsküla, P F; Luis Fuentes, V; Connolly, D J
2015-01-01
Tricuspid annular plane systolic excursion (TAPSE) is a useful estimate of right ventricular function in humans. Reference intervals for dogs have been generated, but the value of measuring TAPSE in other diseases, or investigating the association between TAPSE and outcome, is unknown. TAPSE is lower in Boxer dogs with ≥50 VPCs/24 h on Holter than in dogs with fewer ventricular ectopics, and lower TAPSE is associated with a shorter survival time. Fifty Boxer dogs that presented for investigation of syncope or suspected arrhythmogenic right ventricular cardiomyopathy (ARVC) at a veterinary teaching hospital (2004-2011). Retrospective study. Clinical records, Holter, and echocardiographic data were reviewed. TAPSE was measured in a blinded manner on stored echocardiographic cine-loops using anatomic M-mode. Outcome information was obtained and death was classified as cardiac or noncardiac. Survival analysis was performed using Kaplan-Meier curves and Cox proportional hazards models. TAPSE was lower in Boxers with ≥50 VPCs/24 h (13.9 ± 4.04 mm) than Boxers with 4.09, 95%CI 1.15-16.9, P Boxer dogs, including those with apparently normal systolic function and ≥50 VPCs/24 h on Holter analysis. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.
Energy Technology Data Exchange (ETDEWEB)
Arenja, Nisha [University of Heidelberg, Department of Cardiology, Angiology and Pneumology, Heidelberg (Germany); Kantonsspital Olten, Department of Cardiology, Solothurner Spitaeler AG, Olten (Switzerland); Riffel, Johannes H.; Halder, Manuel; Djiokou, Charly N.; Fritz, Thomas; Andre, Florian; Siepen, Fabian aus dem; Zelniker, Thomas; Meder, Benjamin; Kayvanpour, Elham; Korosoglou, Grigorios [University of Heidelberg, Department of Cardiology, Angiology and Pneumology, Heidelberg (Germany); Katus, Hugo A. [University of Heidelberg, Department of Cardiology, Angiology and Pneumology, Heidelberg (Germany); DZHK (German Centre for Cardiovascular Research), partner site Heidelberg, Heidelberg (Germany); Buss, Sebastian J. [University of Heidelberg, Department of Cardiology, Angiology and Pneumology, Heidelberg (Germany); Das Radiologische Zentrum - Radiology Center, Sinsheim-Eberbach-Erbach-Walldorf-Heidelberg (Germany)
2017-09-15
To investigate the association of right ventricular long axis strain (RV-LAS), a parameter of longitudinal function, with outcome in patients with non-ischaemic dilated cardiomyopathy (NIDCM). In 441 patients with NIDCM, RV-LAS was analysed retrospectively by measuring the length between the epicardial border of the left ventricular apex and the middle of a line connecting the origins of the tricuspidal valve leaflets in end-diastole and end-systole on non-contrast standard cine sequences. The primary endpoint (cardiac death or heart transplantation) occurred in 41 patients, whereas 95 reached the combined endpoint (including cardiac decompensation and sustained ventricular arrhythmias) during a median follow-up of 4.2 years. Kaplan-Meier survival curves showed a poor outcome in patients with RV-LAS values below -10% (log-rank, p < 0.0001). In a risk stratification model RV-LAS improved prediction of outcome in addition to RV ejection fraction (RVEF) and presence of late gadolinium enhancement. Assessment of RV-LAS offered incremental information compared to clinical symptoms, biomarkers and RVEF. Even in the subgroup with normal RVEF (>45%, n = 213) reduced RV-LAS was still associated with poor outcome. Assessment of RV-LAS is an independent indicator of outcome in patients with NIDCM and offers incremental information beyond clinical and cardiac MR parameters. (orig.)
Asai, Shuji; Fujibayashi, Takayoshi; Oguchi, Takeshi; Hanabayashi, Masahiro; Hayashi, Masatoshi; Matsubara, Hiroyuki; Ito, Takayasu; Yabe, Yuichiro; Watanabe, Tsuyoshi; Hirano, Yuji; Kanayama, Yasuhide; Kaneko, Atsushi; Kato, Takefumi; Takagi, Hideki; Takahashi, Nobunori; Funahashi, Koji; Takemoto, Toki; Asai, Nobuyuki; Watanabe, Tatsuo; Ishiguro, Naoki; Kojima, Toshihisa
2018-03-01
This study aimed to investigate predictors of biologic discontinuation due to insufficient response as a surrogate for relapse in patients with rheumatoid arthritis (RA) who achieved clinical remission with biologic treatment. This study was performed based on data from a multicenter registry, and included 404 patients who achieved clinical remission within the first year of treatment with their first biologic. Cumulative retention rate of the first biologic was estimated using Kaplan-Meier curves, and the impact of patient characteristics on biologic discontinuation was assessed with Cox proportional hazards models. During follow-up, 50 patients discontinued their first biologic due to insufficient response. Overall discontinuation rates due to insufficient response after achieving remission were 6%, 11%, and 19% at 1, 2, and 5 years, respectively. Multivariate analysis revealed that concomitant glucocorticoids at achieving remission [hazard ratio (HR): 3.80, 95% confidence interval (CI): 1.89-7.64)] and a higher level of C-reactive protein (CRP) at achieving remission (HR: 1.47 per 1 mg/dL, 95% CI: 1.09-1.99) independently predict discontinuation due to insufficient response after achieving remission. Patients with RA who achieved remission with concomitant glucocorticoid treatment and a higher level of CRP are at high risk of subsequent biologic discontinuation due to insufficient response.
Directory of Open Access Journals (Sweden)
Klaus J. Schmitz
2007-02-01
Full Text Available BACKGROUND/AIMS: The GNAS1 locus encodes the Gas protein, which stimulates the formation of cycloadenosinemonophosphate (cAMP. The cAMP pathway mediates pleiotropic effects, including the regulation of apoptosis and proliferation. We have recently shown that TT genotypes of the single-nucleotide polymorphism T393C in the gene GNAS1 predict the clinical outcome of patients with various carcinomas. METHODS: Eighty-seven patients with intrahepatic cholangiocarcinoma (ICC were retrospectively genotyped to elucidate a potential association between T393C genotypes and clinical outcome. RESULTS: ICCs of patients with homozygous TT genotypes revealed a higher proliferation rate and a lower apoptotic rate. Homozygous TT patients were at highest risk for cancer-related deaths (hazard ratio = 2.74; 95% confidence interval = 1.03-7.28 compared with C-allele carriers. Kaplan-Meier curves for disease-specific overall and local recurrence-free survival in a subgroup with Ro-resected ICC showed a significant association of T393 homozygosity with outcome, which was confirmed in multivariate Cox regression analysis. CONCLUSIONS: GNAS1 T393C is a novel independent host factor for disease progression in patients with ICC. Our finding that TT homozygosity (and not CC homozygosity was associated with unfavorable clinical outcome points to the complex and differing functional effects induced by GNAS1 T393C polymorphism in various human carcinomas.
International Nuclear Information System (INIS)
Bannura C, Guillermo; Vargas N, Claudio; Barrera E, Alejandro; Melo L, Carlos; Illanes F, Felipe
2013-01-01
Background: Preoperative chemo radiotherapy improves the prognosis of locally advanced low rectal cancer and induces a pathological response in the tumor, which may have prognostic value. Aim: To assess the results of rectal cancer treatment according to the degree of pathological response of the tumor after chemo radiotherapy. Patients and Methods: All patients with a locally advanced rectal cancer located within 11 cm of the rectal margin, subjected to preoperative chemo radiotherapy followed by surgical treatment in a period of 13 years, were included. Pathological response was classified as complete, intermediate and poor. The tumor was staged according to TNM 2002 classification. Survival was analyzed with Kaplan Meier curves and Cox regression. Results: Patients were followed for a mean of 50 months (range 18-156). Exclusive and global local relapse was observed in 3 and 9.6% of patients, respectively. Pathological response was complete in 13 patients (none died), intermediate in 23 (three died) and poor in 68 (22 died). Global five years survival was 74%. There was a concordance of 0.64 between survival and pathological response. The concordance between survival and TNM classification was 0.69. Conclusions: The pathological response of the tumor to chemo radiotherapy has a good concordance with prognosis, although it is not superior to the final pathological status
International Nuclear Information System (INIS)
Hillerdal, Victoria; Ramachandran, Mohanraj; Leja, Justyna; Essand, Magnus
2014-01-01
Adoptive transfer of T cells genetically engineered with a chimeric antigen receptor (CAR) has successfully been used to treat both chronic and acute lymphocytic leukemia as well as other hematological cancers. Experimental therapy with CAR-engineered T cells has also shown promising results on solid tumors. The prostate stem cell antigen (PSCA) is a protein expressed on the surface of prostate epithelial cells as well as in primary and metastatic prostate cancer cells and therefore a promising target for immunotherapy of prostate cancer. We developed a third-generation CAR against PSCA including the CD28, OX-40 and CD3 ζ signaling domains. T cells were transduced with a lentivirus encoding the PSCA-CAR and evaluated for cytokine production (paired Student’s t-test), proliferation (paired Student’s t-test), CD107a expression (paired Student’s t-test) and target cell killing in vitro and tumor growth and survival in vivo (Log-rank test comparing Kaplan-Meier survival curves). PSCA-CAR T cells exhibit specific interferon (IFN)-γ and interleukin (IL)-2 secretion and specific proliferation in response to PSCA-expressing target cells. Furthermore, the PSCA-CAR-engineered T cells efficiently kill PSCA-expressing tumor cells in vitro and systemic treatment with PSCA-CAR-engineered T cells significantly delays subcutaneous tumor growth and prolongs survival of mice. Our data confirms that PSCA-CAR T cells may be developed for treatment of prostate cancer
Boin, I F S F; de Ataide, E C; Dias, E P O; Stucchi, R S B; Seva-Pereira, T; Calomeni, G; Capel Junior, C C; Mazzali, M
2012-10-01
Renal insufficiency can be associated with poor long-term survival of liver transplant recipients. The objective of this study was to study renal insufficiency observed pretransplantation and its long-term impact after liver transplantation. We analyzed retrospectively an electronic database collected prospectively including transplant records from June 1994 to October 2010 using piggyback venous reconstruction. The exclusion criteria were chronic kidney disease, acute hepatic failure, children up to 12 years of age, and retransplantations. Renal insufficiency was defined by the creatinine clearance (CCr) calculated using the Cockcroft-Gault method. Patients were distributed into 3 groups: CCr >90, between 90 and 60, and >60 mL/min/1.73 m(2). The survival rate was calculated using the Kaplan-Meier method and proportional hazards Cox regression analysis using death and CCr as stratifying variables evaluated predictive factors for survival. The groups were compared using the Kruskal-Wallis test with significant differences at P 90 were 187/59.9% and 82/26.3%, 60 to 90 were 77/24.7% and 74/23.7%, or renal dysfunction (Chi square = 100.6064; P = .00001). The area under the curve (AUC) obtained using an receiver operating characteristic (ROC) analysis was 0.563 (95% CI 0.498-0.627) with a cut off of 30.25. Pre-liver transplantation renal insufficiency seemed to be a predictive factor for long-term survival. Copyright © 2012 Elsevier Inc. All rights reserved.
Gettman, Matthew T.
2008-02-01
Purpose: To evaluate outcomes among a matched cohort of prostate cancer patients treated with radical retropubic prostatectomy (RRP) and robot assisted radical prostatectomy (RARP). Materials and methods: Between 2002 and 2005, 294 patients underwent RARP at our institution. Comparison RRP patients were matched 2:1 for surgical year, age, PSA, clinical stage, and biopsy grade (n=588). Outcomes among groups were compared. From an oncologic standpoint, pathologic features among groups were assessed and Kaplan-Meier estimates of PSA recurrence free survival were compared. Results: Overall margin positivity was not significantly different between groups (RARP, 15.6%, RRP, 17%), yet risk of apical margin was significantly less with RARP. RARP was associated with significantly shorter hospitalization (ptransfusion (p group (16% vs 10%, pgroup (6.6% pgroups was equivalent (p=0.15). Potency at 1 year was better among RARP patients (p=0.02). At a median followup of 1.3 years, PSA recurrence free estimates were not significantly different (92% vs 92%, p=0.69). Conclusions: Early complications were higher in this RARP group, but this experience includes cases performed in the learning curve. Oncologic, quality of life, and functional data in this study revealed encouraging results for RARP when compared to RRP.
Projected dynamics of colonoscopic screening and surveillance for colorectal cancer.
Gheorghe, Cristian; Iacob, Razvan; Gheorghe, Liana; Cotruta, Bogdan; Bancila, Ion; Iacob, Speranta; Bucur, Dana; Voinea, Dana; Popescu, Irinel
2008-01-01
We used a simulation model of statistical analysis to estimate the cost and procedural burden of colorectal cancer (CRC) screening and surveillance using colonoscopy. The estimated financial resources have been evaluated by multiplying half of the scheduled colonoscopies with the cost of one surveillance colonoscopy, dividing the result to the median time in which the procedures are performed, according to the Kaplan-Meier curve of scheduled procedures. Three hundred and thirty-eight patients (72.5%) were included in the registry for colonoscopic surveillance after a curative resection for colorectal cancer, 101 patients (21.7%) for follow-up after endoscopic polypectomies of adenomatous polyps, 21 patients (4.5%) for long lasting inflammatory bowel disease (IBD), and 2 patients (0.4%) for familial adenomatous polyposis. The projected dynamics and costs of colonoscopies scheduled for one year in our center indicate 11650 Euro/9.4 months spending for all procedures, 8450 Euro/8.8 months for surveillance after curative resection for CRC, 2525 Euro/24.9 months for surveillance after endoscopic polypectomies of adenomatous polyps and 525 Euro/6.8 months for screening for CRC in patients with long history of IBD, respectively. Screening and surveillance for CRC in a Romanian gastroenterology center represents an important activity in both workload and costs.
[Survival in renal transplant recipients in Colombia, 2008-2012].
Osorio-Arango, Karime; Beltrán-Durán, Mauricio; Arias-Murillo, Yazmín; Prieto, Franklyn; Robayo, Adriana
2017-06-01
The Red Nacional de Donación y Trasplantes of the Colombian Instituto Nacional de Salud reported that in 2014, 1,059 organ transplants were performed, of which 761 were kidney transplants, and 643 (84.5%) of these were from cadaveric organ donors. To describe the socio-demographic characteristics of patients who received renal transplants, as well as their outcomes in terms of survival. National kidney transplants were analyzed through an observational retrospective cohort study. Overall survival was estimated using the Kaplan-Meier method. The survival curves by sex, age, type of donor, type of insurance, and time on the waiting list were compared utilizing the log rank hypothesis and a Cox regression. A total of 3,980 patients were included, of whom 338 died according to the Registry of Affiliates. The median follow-up time was 49 months, overall survival was 6.35 years (95% CI: 6.30 to 6.40), the one-year survival following transplantation was 97.2%, the three-year survival, 93.2%, and the five-year survival, 90.8%. The survival rate was higher in patients under 50 years of age, receptors of living donor transplants, and with less than six months on the waiting list. The results obtained serve as the basis for future studies with strict monitoring of survival among kidney transplant recipients in Colombia.
Qin, Chong-Zhen; Lou, Xiao-Ya; Lv, Qiao-Li; Cheng, Lin; Wu, Na-Yiyuan; Hu, Lei; Zhou, Hong-Hao
2015-10-01
MicroRNA-184 (miR-184) is found to be significantly deregulated in human cancers associated with tumorigenesis and progression. In this study, we aimed to investigate the role and mechanism of miR-184 expression in epithelial ovarian cancer (EOC). Relative expression of miR-184 was measured by quantificational real-time polymerase chain reaction assay (qRT-PCR) in 80 EOC patients. Kaplan-Meier curve and the log-rank test were conducted to detect the prognostic value of miR-184. Function assays including cell proliferation, apoptosis and inflammation were further explored in vitro. We found that miR-184 was down-regulated in EOC tissues and cell lines compared with paired non-cancerous tissues and IOSE, respectively. Moreover, miR-184 was expressed at significantly lower levels in late-stage (III/IV) EOC tissues. Cox regression multivariate analysis indicated that miR-184 and FIGO stage were independent prognostic indicators for EOC patients. Patients with high miR-184 level achieved significantly a higher 5-year survival rate compared with low level group (P 184 over-expression could suppress EOC cell proliferation as well as inflammation and induce apoptosis in vitro. Altogether, our results suggest that miR-184 together with pathologic diagnosis is critical for prognosis determination in EOC patients and help select treatment strategy.
Pregnancy-related deaths and complications in women with vascular Ehlers-Danlos syndrome.
Murray, Mitzi L; Pepin, Melanie; Peterson, Suzanne; Byers, Peter H
2014-12-01
The purpose of this study was to characterize the nature and magnitude of pregnancy risks in women with vascular Ehlers-Danlos syndrome. Pregnancy-related death rate was determined by a review of pedigrees of families with vascular Ehlers-Danlos syndrome. Maternal morbidity was characterized through semistructured interviews with women with vascular Ehlers-Danlos syndrome or their next of kin. Pregnancy-related deaths occurred in 30 of 565 deliveries (5.3%). There was no difference in Kaplan-Meier survival curves between parous versus nulliparous women with vascular Ehlers-Danlos syndrome. Interviews with 39 women indicated that 46% of deliveries were uncomplicated. The most common pregnancy-related complications were third-/fourth-degree lacerations (20%) and preterm delivery (19%). Life-threatening complications occurred in 14.5% of deliveries and included arterial dissection/rupture (9.2%), uterine rupture (2.6%), and surgical complications (2.6%). There were 5 maternal deaths in 76 deliveries (6.5%). The risk of pregnancy-related complications is increased in women with vascular Ehlers-Danlos syndrome compared with the general population; however, survival data indicate that pregnancy does not appear to affect overall mortality compared with nulliparous women with vascular Ehlers-Danlos syndrome. The data were insufficient to determine whether mode or timing of delivery influenced risk of complications. Women with vascular Ehlers-Danlos syndrome should be engaged in a shared decision-making process when contemplating pregnancy and pregnancy management.
Wada, Hideki; Dohi, Tomotaka; Miyauchi, Katsumi; Doi, Shinichiro; Konishi, Hirokazu; Naito, Ryo; Tsuboi, Shuta; Ogita, Manabu; Kasai, Takatoshi; Okazaki, Shinya; Isoda, Kikuo; Suwa, Satoru; Daida, Hiroyuki
2017-11-01
Recently, malnutrition has been shown to be related to worse clinical outcomes in patients with heart failure. However, the association between nutritional status and clinical outcomes in patients with coronary artery disease (CAD) remains unclear. We investigated the prognostic value of malnutrition assessed by the Controlling Nutritional Status (CONUT; range 0-12, higher = worse, consisting of serum albumin, cholesterol and lymphocytes) score in patients with CAD. The CONUT score was measured on admission in a total of 1987 patients with stable CAD who underwent elective percutaneous coronary intervention (PCI) between 2000 and 2011. Patients were divided into two groups according to their CONUT score (0-1 vs. ≥2). The incidence of major adverse cardiac events (MACE), including all-cause death and non-fatal myocardial infarction, was evaluated. The median CONUT score was 1 (interquartile range 0-2). During the median follow-up of 7.4 years, 342 MACE occurred (17.2%). Kaplan-Meier curves revealed that patients with high CONUT scores had higher rates of MACE (log-rank p Nutritional status assessed by the CONUT score was significantly associated with long-term clinical outcomes in patients with CAD. Pre-PCI assessment of the CONUT score may provide useful prognostic information.
Yang, S W; Liu, Z M; Mi, J R; Liu, S Y; Ding, L G; Chen, K P; Hua, W; Zhang, S
2017-03-24
Objective: To assess the relationship between serum albumin level and clinical outcome in heart failure (HF) patients receiving cardiac resynchronization therapy (CRT). Methods: In this retrospective cohort study, 357 consecutive chronic heart failure patients receiving CRT between January 2010 and December 2015 were enrolled and divided into two groups based on pre-CRT serum albumin (albumin≥40 g/L, n =244; albuminheart transplantation) and rehospitalization due to worsening HF.Baseline characteristics were compared and all-cause mortality (including heart transplantation) and rehospitalization due to worsening heart failure (HF) were analyzed using Kaplan-Meier curves.Prognostic value of albumin level was evaluated in Cox proportional-hazards regression models. Results: Over a median follow-up time of 21 months, 45 patients (12.6%) died, 4 patients (1.1%) underwent heart transplantation and 100 patients (28.0%) were rehospitalized due to worsening HF. HF patients with pre-CRT albuminheart failure in CRT recipients.Patients with lower pre-CRT albumin level face increased risk of all-cause mortality and HF rehospitalization in chronic heart failure patients receiving cardiac resynchronization.
Association between autoimmune disease and cutaneous melanoma with regard to melanoma prognosis.
Bottoni, U; Paolino, G; Ambrifi, M; Didona, D; Albanesi, M; Clerico, R; Lido, P; Brachini, A; Corsetti, P; Richetta, A G; Cantisani, C; Calvieri, S
2015-04-01
An association between autoimmune disease and malignant melanoma (MM) has often been reported in the literature as a positive prognostic factor for MM. Consequently, we evaluated the influence of different autoimmune diseases on the prognosis of MM. To evaluate the prognosis of patients with MM who also had an autoimmune disorder, whether tumour-associated, paraneoplastic or drug-induced. Autoimmune diseases were classified and analysed as tumour-associated, paraneoplastic or drug-induced. Patients were enrolled according to their clinicopathological features and matched with control groups. Kaplan-Meier analysis was used to estimate disease-free survival (DFS) and overall survival (OS), and log-rank test was used to evaluate differences between the survival curves. In total, 49 patients with MM and tumour-associated autoimmune disease were included in our analysis. No case of paraneoplastic autoimmune disease was detected. The survival analyses showed a range of results, from a worsening of DFS and OS to a lack of any difference. In a second analysis, we separately analysed patients who developed autoimmune disorders after starting adjuvant therapy with interferon-α; we did not find significant differences between these patients and the untreated patients. Autoimmune disease, whether tumour-associated or drug-induced, was not associated with better prognosis in patients with MM. The results suggest that the reported relationship between autoimmunity and MM may be a result of individual variation in sensitivity to the autoimmune disease, the tumour or the treatments. © 2014 British Association of Dermatologists.
Fenstad, Anne M; Dale, Håvard; Havelin, Leif; Hallan, Geir; Overgaard, Søren; Pedersen, Alma B; Kärrholm, Johan; Garellick, Göran; Pulkkinen, Pekka; Eskelinen, Antti; Mäkelä, Keijo; Engesæter, Lars B; Fevang, Bjørg-Tilde
2015-01-01
Background and purpose Medical treatment of rheumatoid arthritis (RA) has changed dramatically over the last 15 years, including immune modulation. We investigated the risk of revision for infection after primary total hip replacement (THR) in patients with rheumatoid arthritis over a 16-year period, and compared it with that in THR patients with osteoarthritis (OA). Patients and methods We identified 13,384 THRs in RA patients and 377,287 THRs in OA patients from 1995 through 2010 in a dataset from the Nordic Arthroplasty Register Association (NARA). Kaplan-Meier survival curves, with revision for infection as the endpoint, were constructed. Cox regression analyses were performed to calculate the relative risk (RR) of revision for infection adjusted for age, sex, fixation technique, and year of primary surgery. Results RA patients had a 1.3 times (95% CI 1.0–1.6) higher risk of revision for infection. After 2001, this risk increased more for RA patients than for OA patients. During the first 3 months and from 8 years postoperatively, the risk of revision for infection was higher in RA patients with THRs fixated with antibiotic-loaded cement than in corresponding OA patients. Interpretation We found a slightly higher overall risk of revision for infection in RA patients than in OA patients, but this difference was only present after 2001. In THRs with antibiotic-loaded cement, the risk of very early and late infections leading to revision was higher in RA patients than in OA patients. PMID:25782042
Arduino, Paolo G; Carrozzo, Marco; Chiecchio, Andrea; Broccoletti, Roberto; Tirone, Federico; Borra, Eleonora; Bertolusso, Giorgio; Gandolfo, Sergio
2008-08-01
This retrospective hospital-based study reviewed and evaluated the outcome of patients with oral squamous cell carcinoma (OSCC) with the aim of identifying factors affecting the clinical course and survival rate. Patients with a follow-up of at least 12 months were included. The data collected were statistically analyzed for the presence of factors valuable for prognosis; survival curves were processed in accordance with the Kaplan-Meier method. Differences in the expression of variables in different grading levels were investigated. Cox's proportional hazard model for Z(i) covariates (grading, age, T, N) also was calculated. Mean patient age was 67.7 years in women (n = 152) and 62.4 years in men (n = 182). A total of 98 patients were identified with Broder's/World Health Organization grade 1 histology, 176 with grade 2, and 55 with grade 3; 5 patients were identified as grade 4 (carcinoma in situ). Gender and risk factors seemed to be unrelated to prognosis, whereas a significant increase in mortality was seen in patients over age 70. Histological grading, tumor size, and neck involvement were related, as independent factors, in predicting survival in patients with OSCC (QM-H > 3.9). Gender, age, and risk factors had no statistical relationship with cancer histological differentiation. Our analysis reveals a statistically significant relationship among histological Broder's grading of malignancy, tumor size, locoregional involvement, and survival rates, underscoring the utility of tumor differentiation in predicting the clinical course and outcome of OSCC.
Wang, Yaping; Huang, Jie; Rong, Liucheng; Wu, Peng; Kang, Meiyun; Zhang, Xuejie; Lu, Qin; Fang, Yongjun
2016-12-13
Age at diagnosis is a key factor for predicting the prognosis of pediatric leukemia especially regarding the survivorship assessment. In this study, we aimed to assess the impact of this prognostic factor such as age in children with pediatric leukemia. In this study, Surveillance, Epidemiology, and End Results Program-registered children with leukemia during 1988-2013 were analyzed. All patients were divided into five groups according to the age at the time of diagnosis (15 years old). Kaplan-Meier and multivariable Cox regression models were used to evaluate leukemia survival outcomes and risk factors. There was significant variability in pediatric leukemia survival by age at diagnosis including ALL, AML and CML subtypes. According to the survival curves in each group, survival rate were peaked among children diagnosed at 1-4 years and steadily declined among those diagnosed at older ages in children with ALL. Infants (pediatric leukemia. Age at diagnosis remained to be a crucial determinant of the survival variability of pediatric leukemia patients.
Preoperative Serum Carcinoembryonic Antigen as a Marker for Predicting the Outcome of Three Cancers
Nan, Jingzhu; Li, Juan; Li, Xiujuan; Guo, Guanghong; Wen, Xinyu; Tian, Yaping
2017-01-01
BACKGROUND Serum levels of carcinoembryonic antigen (CEA) are associated with a variety of tumors. OBJECTIVE This study evaluated the prognostic value of pretreatment serum CEA levels in predicting the outcomes of multiple tumors subjected to treatment. METHODS Prior to therapy, serum samples from 71 prostate, 46 breast, 77 gastric, and 31 pancreatic cancer patients were collected to examine serum CEA levels. The cutoff value for CEA was set as determined by the maximum Youden index. The data were analyzed by the Kaplan-Meier curves generated by the log-rank test and Cox multivariate analysis. RESULTS The overall survival rate for all the patients was 71.11%. The 3-year survival rate of patients with prostate, breast, gastric, and pancreatic cancers was 81.69%, 95.65%, 54.55%, and 51.61%, respectively. The 3-year survival rate showed significant statistical differences between patients with serum CEA levels <2.885 µg/L and those with serum CEA levels ⩾2.885 µg/L (P < .001). The statistical differences of the 3-year survival rate also existed in the men (P = .010) or women group (P < .001), as well as in the 3 different types of cancer, which include breast cancer (P = .025), gastric cancer (P = .001), and pancreatic cancer (P = .047). CONCLUSIONS Serum CEA levels can provide additional prognostic information and may be useful in treatment implementation for patients with breast, gastric, or pancreatic cancer. PMID:28469484
Increasing trends in kidney cancer over the last 2 decades in Saudi Arabia.
Alkhateeb, Sultan S; Alkhateeb, Jawaher M; Alrashidi, Eman A
2015-06-01
To examine the trends of kidney cancer over the last 2 decades in a subset of a Saudi Arabian population. We conducted a retrospective study in a tertiary care center including all adult patients with primary kidney cancer who presented and were managed between 1990 and 2010. The time period was split into 4 quartiles, and variables tested and compared using chi-square, T-test, and Kaplan-Meier curves for survival. The total was 215 patients with a mean age of 57.8 years. There was an increase in the number of kidney cancer cases over the last 2 decades. There was no significant difference in the mode of presentation or stage distribution between quartiles. A significant change was observed in the management towards minimally invasive and nephron-sparing surgeries (p less than 0.001). There was no change in recurrence-free and disease-specific survival over the last 20 years. There have been an increasing number of kidney cancer patients over the last 2 decades with no observed migration towards more incidental and low stage tumors as compared with developed countries.
Comparison of minocycline and azithromycin for the treatment of mild scrub typhus in northern China.
Zhao, Minxing; Wang, Ting; Yuan, Xiaoyu; Du, Weiming; Lin, Miaoxin; Shen, Yanbo
2016-09-01
Scrub typhus, caused by Orientia tsutsugamushi, has recently emerged in northern China where the disease had not been known to exist. Although doxycycline and azithromycin are the recommended agents for the treatment of scrub typhus, clinical responses depend both on the susceptibilities of various O. tsutsugamushi strains and the severity of the disease. A retrospective analysis was conducted on patients diagnosed with mild scrub typhus from August 2013 to January 2016 in the Affiliated Hospital of Nantong University, northern China. A total of 40 patients who received minocycline treatment and 34 patients who received azithromycin treatment were included in the analysis. All patients except one defervesced within 120 h after initiating antimicrobial therapy. Kaplan-Meier curves in association with log-rank test showed that the median time to defervescence was significantly shorter for the minocycline-treated group than the azithromycin-treated group (P = 0.003). There were no serious adverse events during treatment. No relapse occurred in either group during the 1-month follow-up period. In conclusion, both minocycline and azithromycin are effective and safe for the treatment of mild scrub typhus, but minocycline is more active than azithromycin against O. tsutsugamushi infection acquired in northern China. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.
Directory of Open Access Journals (Sweden)
Henry C. Ndukwe
2015-12-01
Full Text Available Background: Donepezil is indicated for the management of mild to moderate dementia, particularly in Alzheimer's disease. Several studies have described low adherence rates with donepezil. Aim: To examine and measure donepezil adherence, persistence and time to first discontinuation in older New Zealanders. Methods: An inception cohort of 1,999 new users of donepezil, aged 65 years or older, were identified from the Pharmaceutical Collections and National Minimum Dataset from 1 November 2010 to 31 December 2013. Kaplan-Meier curves and Cox regression analysis were used to estimate the cumulative probability and risk of time to first discontinuation of donepezil therapy. Results: The mean age of the cohort was 79.5 ± 6.4 years and included 42.7% females. Adherence was high (89.0%, while the proportion of donepezil dispensings (81.0-32.5% declined between 6 and 36 months. Persistence between the 1st and 6th dispensing visit decreased by 19.0%, and 11.0% of the total cohort had a gap of 31 days or more. The adjusted risk of time to first discontinuation in the non-adherent group was 2.2 times (95% CI 1.9-2.6 that of the adherent group. Conclusions: The non-adherent new donepezil users, on average, discontinued faster than the adherent group. Time to first discontinuation in this study was higher compared to discontinuation rates observed in clinical trials.
Ndukwe, Henry C; Nishtala, Prasad S
2015-01-01
Donepezil is indicated for the management of mild to moderate dementia, particularly in Alzheimer's disease. Several studies have described low adherence rates with donepezil. To examine and measure donepezil adherence, persistence and time to first discontinuation in older New Zealanders. An inception cohort of 1,999 new users of donepezil, aged 65 years or older, were identified from the Pharmaceutical Collections and National Minimum Dataset from 1 November 2010 to 31 December 2013. Kaplan-Meier curves and Cox regression analysis were used to estimate the cumulative probability and risk of time to first discontinuation of donepezil therapy. The mean age of the cohort was 79.5 ± 6.4 years and included 42.7% females. Adherence was high (89.0%), while the proportion of donepezil dispensings (81.0-32.5%) declined between 6 and 36 months. Persistence between the 1st and 6th dispensing visit decreased by 19.0%, and 11.0% of the total cohort had a gap of 31 days or more. The adjusted risk of time to first discontinuation in the non-adherent group was 2.2 times (95% CI 1.9-2.6) that of the adherent group. The non-adherent new donepezil users, on average, discontinued faster than the adherent group. Time to first discontinuation in this study was higher compared to discontinuation rates observed in clinical trials.
Hsieh, Meng-Heng; Wang, Tsai-Yu; Yu, Chih-Teng; Chou, Chun-Liang; Lin, Shu-Min; Kuo, Chih-Hsi; Chung, Fu-Tsai
2014-01-01
Although malignant endobronchial mass (MEM) has poor prognosis, cryotherapy is reportedly a palliative treatment. Clinical data on postcryotherapy MEM patients in a university-affiliated hospital between 2007 and 2011 were evaluated. Survival curve with or without postcryotherapy chemotherapy and performance status (PS) improvement of these subjects were analyzed using the Kaplan-Meier method. There were 59 patients (42 males), with median age of 64 years (range, 51–76, and median performance status of 2 (interquartile range [IQR], 2-3). Postcryotherapy complications included minor bleeding (n = 12) and need for multiple procedures (n = 10), while outcomes were relief of symptoms (n = 51), improved PS (n = 45), and ability to receive chemotherapy (n = 40). The survival of patients with chemotherapy postcryotherapy was longer than that of patients without such chemotherapy (median, 534 versus 106 days; log-rank test, P = 0.007; hazard ratio, 0.25; 95% confidence interval, 0.10–0.69). The survival of patients with PS improvement postcryotherapy was longer than that of patients without PS improvement (median, 406 versus 106 days; log-rank test, P = 0.02; hazard ratio, 0.28; 95% confidence interval, 0.10–0.81). Cryotherapy is a feasible treatment for MEM. With better PS after cryotherapy, further chemotherapy becomes possible for patients to improve survival when MEM caused dyspnea and poor PS. PMID:25383370
Mortality of first world war military personnel: comparison of two military cohorts.
Wilson, Nick; Clement, Christine; Summers, Jennifer A; Bannister, John; Harper, Glyn
2014-12-16
To identify the impact of the first world war on the lifespan of participating military personnel (including in veterans who survived the war). Comparison of two cohorts of military personnel, followed to death. Military personnel leaving New Zealand to participate in the first world war. From a dataset of the New Zealand Expeditionary Forces, we randomly selected participants who embarked on troopships in 1914 and a comparison non-combat cohort who departed on troopships in late 1918 (350 in each group). Lifespan based on dates of birth and death from a range of sources (such as individual military files and an official database of birth and death records). A quarter of the 1914 cohort died during the war, with deaths from injury predominating (94%) over deaths from disease (6%). This cohort had a significantly shorter lifespan than the late 1918 "non-combat" cohort, with median ages of death being 65.9 versus 74.2, respectively (a difference of 8.3 years shown also in Kaplan-Meier survival curves, log rank Pfirst world war in 1914 from New Zealand lost around eight years of life (relative to a comparable military cohort). In the postwar period they continued to have an increased risk of premature death. © Wilson et al 2014.
Saratzis, Athanasios; Sarafidis, Pantelis; Melas, Nikolaos; Saratzis, Nikolaos; Kitas, George
2013-10-01
Renal function may be associated with poor outcome following endovascular abdominal aortic aneurysm repair (EVAR), but this relationship has not been adequately investigated. The aim of this study is to evaluate the association of estimated glomerular filtration rate (eGFR) with cardiovascular events and all-cause mortality after EVAR. Prospective cohort study of patients undergoing elective EVAR; eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration formula, and patients were divided in four groups (eGFR ≥ 90 mL/min/1.73 m(2), group 1; 60-89, group 2; 30-59, group 3; stroke, and vascular complications. Kaplan-Meier curves were constructed, and between-group comparisons were performed adjusted for variables that differed at baseline. A total of 383 patients (mean age, 69 ± 8 years; mean abdominal aortic aneurysm diameter, 6.2 ± 1.4 cm) were included. Over a mean follow-up of 34 ± 12 months, the following events occurred: 20 deaths (5.2%), 15 nonfatal myocardial infarctions (3.9%), 9 nonfatal strokes (2.3%), and 7 peripheral vascular complications (1.8%). Patients with an eGFR function is associated with an increase in cardiovascular events and mortality following elective EVAR. Copyright © 2013 Society for Vascular Surgery. All rights reserved.
Directory of Open Access Journals (Sweden)
Mei-Hsuan Lee
Full Text Available BACKGROUND: The development of a risk assessment tool for long-term hepatocellular carcinoma risk would be helpful in identifying high-risk patients and providing information of clinical consultation. METHODS: The model derivation and validation cohorts consisted of 975 and 572 anti-HCV seropositives, respectively. The model included age, alanine aminotransferase (ALT, the ratio of aspirate aminotransferase to ALT, serum HCV RNA levels and cirrhosis status and HCV genotype. Two risk prediction models were developed: one was for all-anti-HCV seropositives, and the other was for anti-HCV seropositives with detectable HCV RNA. The Cox's proportional hazards models were utilized to estimate regression coefficients of HCC risk predictors to derive risk scores. The cumulative HCC risks in the validation cohort were estimated by Kaplan-Meier methods. The area under receiver operating curve (AUROC was used to evaluate the performance of the risk models. RESULTS: All predictors were significantly associated with HCC. The summary risk scores of two models derived from the derivation cohort had predictability of HCC risk in the validation cohort. The summary risk score of the two risk prediction models clearly divided the validation cohort into three groups (p<0.001. The AUROC for predicting 5-year HCC risk in the validation cohort was satisfactory for the two models, with 0.73 and 0.70, respectively. CONCLUSION: Scoring systems for predicting HCC risk of HCV-infected patients had good validity and discrimination capability, which may triage patients for alternative management strategies.
Low Survival Rates of Oral and Oropharyngeal Squamous Cell Carcinoma
Directory of Open Access Journals (Sweden)
Anna Carolina Omena Vasconcellos Le Campion
2017-01-01
Full Text Available Aim. To assess the epidemiological and clinical factors that influence the prognosis of oral and oropharyngeal squamous cell carcinoma (SCC. Methods. One hundred and twenty-one cases of oral and oropharyngeal SCC were selected. The survival curves for each variable were estimated using the Kaplan-Meier method. The Cox regression model was applied to assess the effect of the variables on survival. Results. Cancers at an advanced stage were observed in 103 patients (85.1%. Cancers on the tongue were more frequent (23.1%. The survival analysis was 59.9% in one year, 40.7% in two years, and 27.8% in 5 years. There was a significant low survival rate linked to alcohol intake (p=0.038, advanced cancer staging (p=0.003, and procedures without surgery (p<0.001. When these variables were included in the Cox regression model only surgery procedures (p=0.005 demonstrated a significant effect on survival. Conclusion. The findings suggest that patients who underwent surgery had a greater survival rate compared with those that did not. The low survival rates and the high percentage of patients diagnosed at advanced stages demonstrate that oral and oropharyngeal cancer patients should receive more attention.
Directory of Open Access Journals (Sweden)
Hsin-Hua Lee
Full Text Available To compare the long-term clinical outcomes of postmastectomy radiotherapy (PMRT between breast cancer patients with and without immediate transverse rectus abdominis myocutaneous (TRAM flap reconstruction.The study included 492 patients with stage II or III breast cancer who underwent modified radical mastectomy (MRM and chemotherapy followed by PMRT between 1997 and 2011. Cox regression model and Kaplan-Meier curves were calculated, and the log-rank test was used to evaluate the differences between overall and disease-free survival rates in the 2 groups.Among 492 patients, 213 patients had immediate TRAM flap reconstruction. The mean follow-up was 7.2 years (range, 11-191 months. The 5-year and 10-year disease free survival rates were 81% and 76% for the TRAM flap group and 78% and 73% for the non-flap group. The 5-year and 10-year overall survival rates were 89% and 73% for the TRAM flap group and 83% and 74% for the non-flap group.There exists no statistically significant difference in the rates of local recurrence, distant metastasis, disease-free and overall survival when comparing immediate TRAM flap reconstruction with no reconstruction. Our results suggest that immediate TRAM flap reconstruction does not compromise long term clinical outcomes in breast cancer patients requiring PMRT.
Survival outcome of malignant minor salivary tumors in Pakistani population
Directory of Open Access Journals (Sweden)
Hassan Iqbal
2014-01-01
Full Text Available Objective: Malignant tumors of minor salivary glands (MSG are rare. Survival outcome in Pakistani population with malignant MSG tumors remains to be defined. The objective of this study was to report the clinical presentation, treatment modalities, and survival outcome of radically treated malignant tumors of MSG in Pakistani population. Materials and Methods: Between April 2003 and March 2011, 45 patients with malignant tumors of MSG were treated at Shaukat Khanum Cancer Hospital and included in the study. Patient characteristics and treatment modalities were assessed and local, regional, and distant failures determined. Relapse-free (RFS and overall survival (OS was calculated using Kaplan-Meier curves, and log-rank test was used to determine significance. Results: Median age was 40 (17-83 years. Male to female ratio was 1.25:1. Most common site was hard palate in 31 (69% patients. Adenoid cystic carcinoma (51% was the most common histological diagnosis. Nine patients (20% underwent surgery as the only treatment modality, six patients received (13% radiotherapy alone, and 30 patients (67% had surgery followed by adjuvant radiotherapy. Eight patients developed recurrence (four local, two regional, one locoregional, and one distant. The 5-year actuarial overall OS and RFS was 77 and 66%, respectively. Age, T-stage, and treatment modality were significant for RFS, whereas T-stage and treatment modality were significant factors for OS. Conclusion: Surgery as single modality or combined with radiation therapy resulted in acceptable survival in Pakistani population with malignant minor salivary tumors.
Lyu, Zhuomin; Chen, Yibing; Guo, Xu; Zhou, Feng; Yan, Zhaoyong; Xing, Jinliang; An, Jiaze; Zhang, Hongxin
2016-12-01
Metabolic reprogramming is an important hallmark of cancer cells, including the alterations of activity and expression of enzymes in glucose metabolism. Previous studies have demonstrated the critical role of glucise-6-phosphate isomerase (GPI) in cancer initiation, metastasis and progression. However, the significance of single nucleotide polymorphisms (SNPs) in GPI gene has not been investigated in hepatocellular carcinoma (HCC). In this study, a total of 3 functional SNPs in GPI gene were genotyped in 492 HCC patients with surgical treatment. Multivariate Cox proportional hazards model and Kaplan-Meier curve were used for the analysis of overall survival (OS) and recurrence-free survival (RFS). The homozygous variant genotypes of rs7248411 in mRNA splice sites of GPI gene were significantly associated with an increased risk of death in the multivariate analysis (Hazard ratio [HR], 2.07; 95% confidence interval [95% CI]: 1.16-3.68 in a recessive model). In stratified analysis, the association remained significant in patients with high α-fetal protein (AFP) level (HR=2.37, 95% CI 1.25-4.49). Moreover, we identified the interaction between rs7248411 and AFP level in predicting the prognosis of HCC patients (P for interaction<0.001). Our data suggest that GPI gene polymorphism may serve as potential biomarkers to predict the OS of HCC. Further studies with different ethnicities are needed to validate our findings and generalize its clinical utility. Copyright Â© 2016 Elsevier Masson SAS. All rights reserved.
[Comparison of peritoneal dialysis and hemodialysis survival in Provence-Alpes-Côte d'Azur].
Habib, Aida; Durand, Anne-Claire; Brunet, Philippe; Delarozière, Jean-Christophe; Devictor, Bénédicte; Sambuc, Roland; Gentile, Stéphanie
2016-07-01
To analyze and compare survival of patients initially treated with peritoneal dialysis (PD) or hemodialysis (HD). We used data from the French REIN registry. We included all patients aged 18 years or more who started dialysis between 1st January 2004 and 12 December 2012 in Provence-Alpes-Côte d'Azur Region (PACA). These patients were followed up until 30 June 2014. Survival curves were generated using the Kaplan-Meier technique and tested using the log-rank test. Variables predictive of all-cause mortality were determined using Cox regression models. The propensity score was used. Survival was similar between initial dialysis modalities: PD and HD, even after adjusting for the propensity score. But, when we exclude the patients who had switched from one technique of dialysis to another, survival was better in HD patients. According to the multivariate analysis, advanced age and the lack of walking autonomy appear to be associated with an increase in mortality in dialysis patients. But, the presence of hypertension improve the survival in this cohort. The survival is similar between hemodialysis and peritoneal dialysis. Copyright © 2016 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.
Directory of Open Access Journals (Sweden)
Olya Grove
Full Text Available Two CT features were developed to quantitatively describe lung adenocarcinomas by scoring tumor shape complexity (feature 1: convexity and intratumor density variation (feature 2: entropy ratio in routinely obtained diagnostic CT scans. The developed quantitative features were analyzed in two independent cohorts (cohort 1: n = 61; cohort 2: n = 47 of patients diagnosed with primary lung adenocarcinoma, retrospectively curated to include imaging and clinical data. Preoperative chest CTs were segmented semi-automatically. Segmented tumor regions were further subdivided into core and boundary sub-regions, to quantify intensity variations across the tumor. Reproducibility of the features was evaluated in an independent test-retest dataset of 32 patients. The proposed metrics showed high degree of reproducibility in a repeated experiment (concordance, CCC≥0.897; dynamic range, DR≥0.92. Association with overall survival was evaluated by Cox proportional hazard regression, Kaplan-Meier survival curves, and the log-rank test. Both features were associated with overall survival (convexity: p = 0.008; entropy ratio: p = 0.04 in Cohort 1 but not in Cohort 2 (convexity: p = 0.7; entropy ratio: p = 0.8. In both cohorts, these features were found to be descriptive and demonstrated the link between imaging characteristics and patient survival in lung adenocarcinoma.
Clinical phenomenology and mortality in Charles Bonnet syndrome.
Lapid, Maria I; Burton, M Caroline; Chang, Megan T; Rummans, Teresa A; Cha, Stephen S; Leavitt, Jacqueline A; Boeve, Bradley F
2013-03-01
Despite existing diagnostic criteria for Charles Bonnet syndrome (CBS), clinical manifestations vary greatly. We examined the clinical course and mortality of patients diagnosed with CBS. We conducted a retrospective chart review of patients with CBS. We collected demographic and clinical information and medical burden scores. Kaplan-Meier mortality curves were compared using log-rank test. Cox proportional hazard model was used for multivariate analysis and hazard ratio (HR). Mortality was compared to expected mortality from Minnesota population. Seventy-seven patients with CBS had a mean age of 79.5 (standard deviation ± 13.0) and were predominantly Caucasian (97%) and female (73%). In all, 20 (26%) subsequently developed a dementia syndrome, most often Lewy body. A total of 46 (60%) deaths occurred with an average follow-up time of 33.0 months. Characteristics associated with mortality included older age (75-84 [HR 3.34, P = .029], >85 [HR 4.58, P = .007]) and renal disease (HR 3.39 with 95% confidence interval 1.31-8.80, P = .012). Medical burden scores were not associated with overall mortality. Mortality was high compared to Minnesota population (P < .0001). A large proportion of patients with CBS developed dementia, and there was a high mortality rate associated with older age and renal disease. Medical burden was not associated with mortality.
Primary intrapulmonary thymoma: a systematic review.
Myers, P O; Kritikos, N; Bongiovanni, M; Triponez, F; Collaud, S; Pache, J-C; Robert, J H
2007-12-01
This article reviews the literature on the clinical features, diagnosis and management of primary intrapulmonary thymoma. Medline, Embase and Cochrane Library searches were performed on all relevant Anglo-Saxon language articles. The search words included "primary pulmonary thymoma" and "intrapulmonary thymoma". Secondary references were obtained from key articles. Prognostic and treatment strategies were analyzed by the Kaplan-Meier method, comparisons between curves were made using log rank test. The searches yielded 25 cases of primary intrapulmonary thymoma. Median follow-up was 9 months (1 day to 13 years). At follow-up, 14 patients were tumor free, one patient had a local recurrence 8 years after radiotherapy, one patient responded favorably to radiotherapy, six patients died and three patients were lost to follow-up. The presence of a paraneoplastic syndrome decreased survival (P=0.02), however, histological subgroup (P=0.216), clinical stage (P=0.63) and tumor size (P=0.288) did not affect survival. Survival in surgically managed patients was significantly better than in conservatively managed patients (P=0.039). Adjuvant radiotherapy did not provide any benefit (P=0.4). Complete resection of primary intrapulmonary thymomas appears sufficient in non-malignant tumors. Because of the risk of late local recurrence, long-term regular clinical follow-up is warranted.
Ventriculoperitoneal (VP) Shunt Survival in Patients Developing Hydrocephalus After Cranial Surgery.
Khan, Farid; Rehman, Abdul; Shamim, Muhammad Shahzad; Bari, Muhammad Ehsan
Ventriculoperitoneal (VP) shunt insertion remains the most popular method for the treatment of hydrocephalus despite its associated complications. We assessed VP shunt survival in a group of patients who had developed hydrocephalus following cranial surgery. A retrospective charts review was done over a 10-year period at our institution. Kaplan-Meier survival curves and Log-Rank (Cox-Mantel) test were used to analyze various factors affecting VP shunt survival. Among the 67 cases included, a total of 28 (46.3%) patients had undergone cranial surgery for brain tumors. The overall rate of shunt failure was 14.9% at a mean follow-up of 16 months. Shunt failure in pediatric patients (20%) was slightly higher than that in adult patients (13.5%). The median time to first shunt failure was adversely influenced by a history of brain tumor (p = 0.019), prolonged antibiotic therapy (p = 0.018) and administration of steroids (p = 0.004). Shunt survival was worse in patients who developed hydrocephalus following cranial surgery performed for brain tumors and those who received either steroids or prolonged antibiotic therapy. Thus post-cranial surgery hydrocephalus represents a unique subset of hydrocephalus.
Botelho, Stephanie Ferreira; Martins, Maria Auxiliadora Parreiras; Vieira, Liliana Batista; Reis, Adriano Max Moreira
2017-04-01
This study investigated postmarketing safety events (PMSEs) for new drugs approved in Brazil and evaluated whether a range of drug characteristics influenced the time between approval and the first PMSE. This retrospective study included new drugs registered between 2003 and 2013 by the National Health Surveillance Agency (ANVISA), which is responsible for medicines approval in Brazil. PMSEs were defined as any drug safety alert or drug withdrawal from the market. The existence of risk evaluation and mitigation strategies (REMS) by the US Food and Drug Administration (FDA) and Brazil were recorded. A Kaplan-Meier survival curve of the period between the date of ANVISA registration and the PMSE was calculated. We found a statistically significant difference between the time to PMSE for drugs with an FDA REMS compared with those without a REMS, with a log rank value (Mantel Cox) of 0.002. There was no association between the time to PMSE and the other drug characteristics investigated. This study demonstrated that the frequency of PMSEs for new drugs approved by ANVISA was statistically associated with the existence of an FDA REMS. The time between approval and first PMSE was shorter for drugs with an FDA REMS, and this finding may contribute to improved awareness of the risk/benefit balance required to ensure continued safe and effective use of new drugs. © 2016, The American College of Clinical Pharmacology.
Directory of Open Access Journals (Sweden)
Yi-Shuan Sheen
Full Text Available Insulin-like growth factor-II mRNA-binding protein 3 (IMP-3 is an RNA-binding protein expressed in multiple cancers, including melanomas. However, the expression of IMP-3 has not been investigated in acral lentiginous melanoma (ALM. This study sought to elucidate its prognostic value in ALMs. IMP-3 expression was studied in 93 patients diagnosed with ALM via immunohistochemistry. Univariate and multivariate analyses for survival were performed, according to clinical and histologic parameters, using the Cox proportional hazard model. Survival curves were graphed using the Kaplan-Meier method. IMP-3 was over-expressed in 70 out of 93 tumors (75.3%. IMP-3 expression correlated with thick and high-stage tumor and predicted poorer overall, melanoma-specific, recurrence-free and distant metastasis-free survivals (P = 0.002, 0.006, 0.008 and 0.012, respectively. Further analysis showed that patients with tumor thickness ≤ 4.0 mm and positive IMP-3 expression had a significantly worse melanoma-specific survival than those without IMP-3 expression (P = 0.048. IMP-3 (hazard ratio 3.67, 95% confidence intervals 1.35-9.97, P = 0.011 was confirmed to be an independent prognostic factor for melanoma-specific survival in multivariate survival analysis. Positive IMP-3 expression was an important prognostic factor for ALMs.
Long-term radiographic follow-up of bisphosphonate-associated atypical femur fractures
Energy Technology Data Exchange (ETDEWEB)
Favinger, Jennifer L. [University of Washington, Department of Radiology, 1959 N.E. Pacific Street, Box 357115, Seattle, WA (United States); Hippe, Daniel [University of Washington, Department of Radiology, Seattle, WA (United States); Ha, Alice S. [University of Washington, Department of Radiology, 4245 Roosevelt Way NE, Box 354755, Seattle, WA (United States)
2016-05-15
To evaluate the appearance of bisphosphonate-related femur insufficiency fractures on long-term follow-up radiographic studies and to describe the rate of fracture line obscuration and cortical beak healing over time. In this retrospective study, bisphosphonate-related femur fracture radiographs were reviewed by two radiologists for the presence of a fracture line, callus, and the characteristic cortical beak. Kaplan-Meier curves were used to analyze the time to first indication of healing. Femurs were also subdivided into those who underwent early versus late surgical fixation and those who underwent early versus late discontinuation of bisphosphonate. Clinical data including pain level and medication history were collected. Forty-seven femurs with a bisphosphonate-related femur fracture were identified in 28 women. Eighty-five percent took a bisphosphonate for greater than 5 years and 59 % for greater than 10 years. The median time to beak healing was 265 weeks and the median time to fracture line healing was 56 weeks in the 31 femurs with a baseline fracture. No statistically significant difference was identified between surgical fixation and conservative management. Bisphosphonate-related fractures demonstrate notably prolonged healing time on long-term follow-up. (orig.)
Acquired urethral obstruction in New World camelids: 34 cases (1995-2008).
Duesterdieck-Zellmer, K F; Van Metre, D C; Cardenas, A; Cebra, C K
2014-08-01
Document the clinical features, short- and long-term outcomes and prognostic factors in New World camelids with acquired urethral obstruction. Retrospective case study. Case data from medical records of 34 New World camelids presenting with acquired urethral obstruction were collected and follow-up information on discharged patients was obtained. Associations with short- and long-term survival were evaluated using Wilcoxon rank-sum tests, exact-logistic regressions and Kaplan-Meier survival curves. Of the 34 New World camelids 23 were intact males and 11 were castrated; 4 animals were euthanased upon presentation, 7 were treated medically and 23 surgically, including urethrotomy, bladder marsupialisation, tube cystostomy alone or combined with urethrotomy, urethrostomy or penile reefing. Necrosis of the distal penis was found in 4 animals and all were short-term non-survivors. Short-term survival for surgical cases was 65%, and 57% for medical cases. Incomplete urethral obstruction at admission and surgical treatment were associated with increased odds of short-term survival. Of 14 records available for long-term follow-up, 6 animals were alive and 8 were dead (median follow-up 4.5 years, median survival time 2.5 years). Recurrence of urethral obstruction was associated with long-term non-survival. Surgically treated New World camelids with incomplete urethral obstruction have the best odds of short-term survival and those with recurrence of urethral obstruction have a poor prognosis for long-term survival. © 2014 Australian Veterinary Association.
Paediatric systemic lupus erythematosus: prognostic impact of antiphospholipid antibodies.
Descloux, E; Durieu, I; Cochat, P; Vital Durand, D; Ninet, J; Fabien, N; Cimaz, R
2008-02-01
The aim of our study was to investigate the prognostic impact of aPL in paediatric onset systemic lupus erythematosus (p-SLE). This retrospective study included 56 patients with p-SLE. Chi2-test, Fisher's exact test, incidence rate ratio and Kaplan-Meier survival curves were used to compare aPL-positive and aPL-negative patients considering the value of SDI (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index for SLE) at the end of follow-up, the occurrence of thromboses, organ system involvements and need for immunosuppressive treatment in addition to corticosteroids. Anti-cardiolipin antibodies and lupus anticoagulants were detected in 27 (49%) and 19 (35%) patients, respectively. These aPL were frequently transient or intermittent (10 and 15 cases, respectively), and only rarely persistent over time (five cases). The risk of thrombosis was significantly higher (odds ratio = 6.42) and occurred earlier in the presence of aPL, especially if aPL were persistent (P or = 1. The risk of damage (SDI > or = 1) in aPL-positive patients was three times higher than in aPL-negative patients (P < 0.05). Four of the six fatal cases occurred in the aPL-positive group. The presence of aPL in p-SLE could represent not only a risk factor for thrombosis but also a poor prognostic factor overall.
Wilms tumor gene 1 (WT1) is a prognostic marker in high-grade uterine sarcoma.
Coosemans, An; Van Calster, Ben; Verbist, Godelieve; Moerman, Philippe; Vergote, Ignace; Van Gool, Stefaan W; Amant, Frédéric
2011-02-01
Wilms tumor gene 1 (WT1) contributes to uterine sarcoma tumor biology. In this study, we aimed to clarify the prognostic value of WT1. A retrospective clinical and histopathological review of 71 women with high-grade uterine sarcoma (leiomyosarcoma [n = 24], undifferentiated sarcoma [n = 9]), and carcinosarcoma (n = 38) was performed. Patients were followed up for at least 12 months. Wilms tumor gene 1 expression was determined by immunohistochemistry. Data on recurrence (progression-free survival) and overall survival (OS) were available for all patients. Univariate and multivariate analyses of WT1 expression were carried out using Kaplan-Meier curves and Cox regression, respectively. Forty-nine (69%) tumors were WT1 positive. Forty-seven (66%) patients died of the disease, with a median OS time of 22 months. Wilms tumor gene 1 was a predictor of survival in the univariate analysis: the hazard ratio of WT1 positivity was 2.44 (95% confidence interval, 1.34-4.71) for progression-free survival and 2.48 (95% confidence interval, 1.26-4.90) for OS. Multivariate analysis including stage, age, tumor size, and sarcoma subtype identified only stage and WT1 positivity as independent prognostic markers for survival. The identification of WT1 as a prognostic marker confirms its role in high-grade uterine sarcoma and carcinosarcoma tumor biology.
Gunnells, Drew J; Wood, Lauren N; Goss, Lauren; Morris, Melanie S; Kennedy, Gregory D; Cannon, Jamie A; Chu, Daniel I
2018-02-01
Conflicting data exist on racial disparities in stoma reversal (SR) rates. Our aim was to investigate the role of race in SR rates, and time to closure, in a longitudinal, racially diverse database. All adult patients (>18 years) who received an ileostomy or colostomy from 1999 to 2016 at a single institution were identified. Primary outcomes were SR rates and time to closure. Failure to reverse and time to closure was modeled using Cox regression. Kaplan-Meier survival curves, stratified by race, were generated for time to closure and hazard ratios (HRs) calculated. Of 770 patients with stomas, 65.6% of patients underwent SR; 76.6% were white and 23.4% were black. On adjusted analysis, race did not predict overall SR rates or time to closure if performed less than 1 year. Instead, significant predictors for failure in SR included age, insurance status, end colostomy/ileostomy, and loop colostomy (p existed only for black patients if reversed more than 1 year after index stoma construction. While equitable outcomes were achieved for most patients, further investigation is necessary to understand stoma disparities after 1 year.
Surface charge method for molecular surfaces with curved areal elements I. Spherical triangles
Yu, Yi-Kuo
2018-03-01
Parametrizing a curved surface with flat triangles in electrostatics problems creates a diverging electric field. One way to avoid this is to have curved areal elements. However, charge density integration over curved patches appears difficult. This paper, dealing with spherical triangles, is the first in a series aiming to solve this problem. Here, we lay the ground work for employing curved patches for applying the surface charge method to electrostatics. We show analytically how one may control the accuracy by expanding in powers of the the arc length (multiplied by the curvature). To accommodate not extremely small curved areal elements, we have provided enough details to include higher order corrections that are needed for better accuracy when slightly larger surface elements are used.
Defining the learning curve for robotic-assisted esophagogastrectomy.
Hernandez, Jonathan M; Dimou, Francesca; Weber, Jill; Almhanna, Khaldoun; Hoffe, Sarah; Shridhar, Ravi; Karl, Richard; Meredith, Kenneth
2013-08-01
The expansion of robotic-assisted surgery is occurring quickly, though little is generally known about the "learning curve" for the technology with utilization for complex esophageal procedures. The purpose of this study is to define the learning curve for robotic-assisted esophagogastrectomy with respect to operative time, conversion rates, and patient safety. We have prospectively followed all patients undergoing robotic-assisted esophagogastrectomy and compared operations performed at our institutions by a single surgeon in successive cohorts of 10 patients. Our measures of proficiency included: operative times, conversion rates, and complications. Statistical analyses were undertaken utilizing Spearman regression analysis and Mann-Whitney U test. Significance was accepted with 95 % confidence. Fifty-two patients (41 male: 11 female) of mean age 66.2 ± 8.8 years underwent robotic-assisted esophagogastrectomies for malignant esophageal disease. Neoadjuvant chemoradiation was administered to 30 (61 %) patients. A significant reduction in operative times (p learning curve for a robotic-assisted procedure appears to begin near proficiency after 20 cases. Operative complications and conversions were infrequent and unchanged across successive 10-patient cohorts.
Approximate Implicitization of Parametric Curves Using Cubic Algebraic Splines
Directory of Open Access Journals (Sweden)
Xiaolei Zhang
2009-01-01
Full Text Available This paper presents an algorithm to solve the approximate implicitization of planar parametric curves using cubic algebraic splines. It applies piecewise cubic algebraic curves to give a global G2 continuity approximation to planar parametric curves. Approximation error on approximate implicitization of rational curves is given. Several examples are provided to prove that the proposed method is flexible and efficient.
Evaluation of the water retention curve of Abidjan Quaternary aquifer ...
African Journals Online (AJOL)
Methods and Results: The water retention curve is difficult to measure in situ on large sites like this aquifer. Kovac's modified model to predict the water retention curve is tested. Predicted curves are compared with in situ measurements points. The results show that, overall, the model predicts well the water retention curves.
Curvature Entropy for Curved Profile Generation
Directory of Open Access Journals (Sweden)
Koichiro Sato
2012-03-01
Full Text Available In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribution, and represents the complexity of a shape (one of the overall shape features. The quadrature curvature entropy is an improvement of the curvature entropy by introducing a Markov process to evaluate the continuity of a curvature and to approximate human cognition of the shape. Additionally, a shape generation method using a genetic algorithm as a calculator and the entropy as a shape generation index is presented. Finally, the applicability of the proposed method is demonstrated using the side view of an automobile as a design example.
Cell Proliferation on Planar and Curved Substrates
Gaines, Michelle; Chang, Ya Wen; Cruz, Ricardo; Fragkopoulos, Alexandros; Garcia, Andres; Fernandez-Nieves, Alberto
Aberrant epithelial collective cell growth is one of the major challenges to be addressed in order to treat diseases such as cancer and organ fibrosis. The conditions of the extracellular microenvironment, properties of the cells' cytoskeleton, and interfacial properties of the substratum (the surface in contact with epithelial cells) have a significant influence on the migratory behavior of epithelial cells, cell proliferation and migration. This work focuses on understanding the impact the substratum curvature has on cell behavior. We focus on cell proliferation first and study MDCK cells on both planar and curved hydrogel substrates. The curved hydrogels are based on polyacrylamide and have toroidal shape, with tube radius 200 um and an aspect ratio in the rage between 2 and 9. Proliferation is measured using the Click-it EDU assay (Invitrogen), which measures cells that are synthesizing DNA. Funding Source is Childrens Healthcare of Atlanta.
Inferring cardiac phase response curve in vivo
Pikovsky, Arkady; Kralemann, Bjoern; Fruehwirth, Matthias; Rosenblum, Michael; Kenner, Thomas; Schaefer, Jochen; Moser, Maximilian
2014-03-01
Characterizing properties of biological oscillators with phase response cirves (PRC) is one of main theoretical tools in neuroscience, cardio-respiratory physiology, and chronobiology. We present a technique that allows the extraction of the PRC from a non-invasive observation of a system consisting of two interacting oscillators, in this case heartbeat and respiration, in its natural environment and under free-running conditions. We use this method to obtain the phase coupling functions describing cardio-respiratory interactions and the phase response curve of 17 healthy humans. We show at which phase the cardiac beat is susceptible to respiratory drive and extract the respiratory-related component of heart rate variability. This non-invasive method of bivariate data analysis for the determination of phase response curves of coupled oscillators may find application in other biological and physical systems.
String field theory in curved space
International Nuclear Information System (INIS)
Kikkawa, Keiji; Maeno, Masahiro; Sawada, Shiro
1988-01-01
The purely cubic action in the string field theory is shown to provide a set of equations of motion for background fields which agree to those obtained by the vanishing condition of β-functions in the non-linear sigma model. Using the sigma model as an auxiliary tool, a systematic method for solving the string field theory in curved space is proposed. (author)
Growth curve models and statistical diagnostics
Pan, Jian-Xin
2002-01-01
Growth-curve models are generalized multivariate analysis-of-variance models. These models are especially useful for investigating growth problems on short times in economics, biology, medical research, and epidemiology. This book systematically introduces the theory of the GCM with particular emphasis on their multivariate statistical diagnostics, which are based mainly on recent developments made by the authors and their collaborators. The authors provide complete proofs of theorems as well as practical data sets and MATLAB code.
Quantum field theory in curved spacetime
International Nuclear Information System (INIS)
Gibbons, G.W.
1978-04-01
The purpose of this article is to outline what the extension of such a treatment to curved space entails and to discuss what essentially new features arise when one takes into account the quantum mechanical nature of gravitating systems. I shall throughout assume a classical, unquantized gravitational field and confine the discussion to matter fields although similar techniques and ideas may be applied to 'gravitons' - that is linearized perturbations of the metric propagating on some fixed, unperturbed, background. (orig./WL) [de
The Green functions in curved spacetime
International Nuclear Information System (INIS)
Buchbinder, I.L.; Kirillova, E.N.; Odinstov, S.D.
1987-01-01
The theory of a free scalar field with conformal coupling in curved spacetime with some special metrics is considered. The integral representations for the green function G-tilde in the form of integrals with Schwinger-De Witt kernel over contours in the complex plane of proper time are obtained. It is shown how the transitions from a unique Green function in Euclidean space to different Green functions in Minkowski space and vice versa can be carried out. (author)
Twisted vector bundles on pointed nodal curves
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
is an element different from the identity and u is a geometric point of U fixed by γ, then the automorphism of the fiber ηu induced by γ is not trivial. 3. An essential action of a finite group on (η,U) is called tame, if the action of on. (U → S, i) is tame. DEFINITION 2.3. Let S be a k-scheme. Let C → S be an n-pointed nodal curve ...
Bezier Curve Modeling for Neutrosophic Data Problem
Directory of Open Access Journals (Sweden)
Ferhat Tas
2017-02-01
Full Text Available Neutrosophic set concept is defined with membership, non-membership and indeterminacy degrees. This concept is the solution and representation of the problems with various fields. In this paper, a geometric model is introduced for Neutrosophic data problem for the first time. This model is based on neutrosophic sets and neutrosophic relations. Neutrosophic control points are defined according to these points, resulting in neutrosophic Bezier curves.
Hydrogen technologies and the technology learning curve
International Nuclear Information System (INIS)
Rogner, H.-H.
1998-01-01
On their bumpy road to commercialization, hydrogen production, delivery and conversion technologies not only require dedicated research, development and demonstration efforts, but also protected niche markets and early adopters. While niche markets utilize the unique technological properties of hydrogen, adopters exhibit a willingness to pay a premium for hydrogen fueled energy services. The concept of the technology learning curve is applied to estimate the capital requirements associated with the commercialization process of several hydrogen technologies. (author)
Stable curves and screens on fatgraphs
DEFF Research Database (Denmark)
Penner, Robert; McShane, Greg
The mapping class group invariant ideal cell decomposition of the Teichmueller space of a punctured surface times an open simplex has been used in a number of computations. This paper answers a question about the asymptotics of this decomposition, namely, in a given cell of the decomposition, whi...... curves can be short? Screens are a new combinatorial structure which provide an answer to this question. The heart of the calculation here involves Ptolemy transformations and the triangle inequalities on lambda lengths....
Feynman propagator in curved space-time
International Nuclear Information System (INIS)
Candelas, P.; Raine, D.J.
1977-01-01
The Wick rotation is generalized in a covariant manner so as to apply to curved manifolds in a way that is independent of the analytic properties of the manifold. This enables us to show that various methods for defining a Feynman propagator to be found in the literature are equivalent where they are applicable. We are also able to discuss the relation between certain regularization methods that have been employed
Rating curve estimation of nutrient loads in Iowa rivers
Stenback, G.A.; Crumpton, W.G.; Schilling, K.E.; Helmers, M.J.
2011-01-01
Accurate estimation of nutrient loads in rivers and streams is critical for many applications including determination of sources of nutrient loads in watersheds, evaluating long-term trends in loads, and estimating loading to downstream waterbodies. Since in many cases nutrient concentrations are measured on a weekly or monthly frequency, there is a need to estimate concentration and loads during periods when no data is available. The objectives of this study were to: (i) document the performance of a multiple regression model to predict loads of nitrate and total phosphorus (TP) in Iowa rivers and streams; (ii) determine whether there is any systematic bias in the load prediction estimates for nitrate and TP; and (iii) evaluate streamflow and concentration factors that could affect the load prediction efficiency. A commonly cited rating curve regression is utilized to estimate riverine nitrate and TP loads for rivers in Iowa with watershed areas ranging from 17.4 to over 34,600km2. Forty-nine nitrate and 44 TP datasets each comprising 5-22years of approximately weekly to monthly concentrations were examined. Three nitrate data sets had sample collection frequencies averaging about three samples per week. The accuracy and precision of annual and long term riverine load prediction was assessed by direct comparison of rating curve load predictions with observed daily loads. Significant positive bias of annual and long term nitrate loads was detected. Long term rating curve nitrate load predictions exceeded observed loads by 25% or more at 33% of the 49 measurement sites. No bias was found for TP load prediction although 15% of the 44 cases either underestimated or overestimate observed long-term loads by more than 25%. The rating curve was found to poorly characterize nitrate and phosphorus variation in some rivers. ?? 2010 .
Numerical Characterization of Piezoceramics Using Resonance Curves
Directory of Open Access Journals (Sweden)
Nicolás Pérez
2016-01-01
Full Text Available Piezoelectric materials characterization is a challenging problem involving physical concepts, electrical and mechanical measurements and numerical optimization techniques. Piezoelectric ceramics such as Lead Zirconate Titanate (PZT belong to the 6 mm symmetry class, which requires five elastic, three piezoelectric and two dielectric constants to fully represent the material properties. If losses are considered, the material properties can be represented by complex numbers. In this case, 20 independent material constants are required to obtain the full model. Several numerical methods have been used to adjust the theoretical models to the experimental results. The continuous improvement of the computer processing ability has allowed the use of a specific numerical method, the Finite Element Method (FEM, to iteratively solve the problem of finding the piezoelectric constants. This review presents the recent advances in the numerical characterization of 6 mm piezoelectric materials from experimental electrical impedance curves. The basic strategy consists in measuring the electrical impedance curve of a piezoelectric disk, and then combining the Finite Element Method with an iterative algorithm to find a set of material properties that minimizes the difference between the numerical impedance curve and the experimental one. Different methods to validate the results are also discussed. Examples of characterization of some common piezoelectric ceramics are presented to show the practical application of the described methods.
Learning curve for radical retropubic prostatectomy
Directory of Open Access Journals (Sweden)
Fernando J. A. Saito
2011-02-01
Full Text Available PURPOSE: The learning curve is a period in which the surgical procedure is performed with difficulty and slowness, leading to a higher risk of complications and reduced effectiveness due the surgeon's inexperience. We sought to analyze the residents' learning curve for open radical prostatectomy (RP in a training program. MATERIALS AND METHODS: We conducted a prospective study from June 2006 to January 2008 in the academic environment of the University of São Paulo. Five residents operated on 184 patients during a four-month rotation in the urologic oncology division, mentored by the same physician assistants. We performed sequential analyses according to the number of surgeries, as follows: = 10, 11 to 19, 20 to 28, and = 29. RESULTS: The residents performed an average of 37 RP each. The average psa was 9.3 ng/mL and clinical stage T1c in 71% of the patients. The pathological stage was pT2 (73%, pT3 (23%, pT4 (4%, and 46% of the patients had a Gleason score 7 or higher. In all surgeries, the average operative time and estimated blood loss was 140 minutes and 488 mL. Overall, 7.2% of patients required blood transfusion, and 23% had positive surgical margins. CONCLUSION: During the initial RP learning curve, we found a significant reduction in the operative time; blood transfusion during the procedures and positive surgical margin rate were stable in our series.
Breakthrough curve moments scaling in hyporheic exchange
Bellin, A.; Tonina, D.; Marzadri, A.
2015-02-01
The interaction between stream flow and bed forms creates an uneven distribution of near-bed energy heads, which is the driving force of hyporheic exchange. Owing to the large disparity of advection characteristic times in the stream and within the hyporheic zone, solute mass exchange is often modeled by considering the latter as an immobile region. In a recent contribution Gónzalez-Pinzón et al. (2013) showed that existing models employing this hypothesis are structurally inconsistent with the scaling revealed by the analysis of 384 breakthrough curves collected in 44 streams across five continents. Motivated by this result, we analyze the scaling characteristics of a model that we recently developed by combining the analytical solution of the advective flow within the hyporheic zone with a Lagrangian solute transport model. Results show that similarly to the experimental data our model predicts breakthrough curves with a constant skewness, irrespective of the stream size, and that the scaling of the first three moments observed by Gónzalez-Pinzón et al. (2013) is also respected. Moreover, we propose regression curves that relate the first three moments of the residence time distribution with the alternate bar dimensionless depth (YBM*), a quantity that is easily measurable in the field. The connection between BTC moments and YBM* opens new possibilities for modeling transport processes at the catchment scale.
Numerical Characterization of Piezoceramics Using Resonance Curves
Pérez, Nicolás; Buiochi, Flávio; Brizzotti Andrade, Marco Aurélio; Adamowski, Julio Cezar
2016-01-01
Piezoelectric materials characterization is a challenging problem involving physical concepts, electrical and mechanical measurements and numerical optimization techniques. Piezoelectric ceramics such as Lead Zirconate Titanate (PZT) belong to the 6 mm symmetry class, which requires five elastic, three piezoelectric and two dielectric constants to fully represent the material properties. If losses are considered, the material properties can be represented by complex numbers. In this case, 20 independent material constants are required to obtain the full model. Several numerical methods have been used to adjust the theoretical models to the experimental results. The continuous improvement of the computer processing ability has allowed the use of a specific numerical method, the Finite Element Method (FEM), to iteratively solve the problem of finding the piezoelectric constants. This review presents the recent advances in the numerical characterization of 6 mm piezoelectric materials from experimental electrical impedance curves. The basic strategy consists in measuring the electrical impedance curve of a piezoelectric disk, and then combining the Finite Element Method with an iterative algorithm to find a set of material properties that minimizes the difference between the numerical impedance curve and the experimental one. Different methods to validate the results are also discussed. Examples of characterization of some common piezoelectric ceramics are presented to show the practical application of the described methods. PMID:28787875
Open Timelike Curves Violate Heisenberg's Uncertainty Principle
Pienaar, J. L.; Ralph, T. C.; Myers, C. R.
2013-02-01
Toy models for quantum evolution in the presence of closed timelike curves have gained attention in the recent literature due to the strange effects they predict. The circuits that give rise to these effects appear quite abstract and contrived, as they require nontrivial interactions between the future and past that lead to infinitely recursive equations. We consider the special case in which there is no interaction inside the closed timelike curve, referred to as an open timelike curve (OTC), for which the only local effect is to increase the time elapsed by a clock carried by the system. Remarkably, circuits with access to OTCs are shown to violate Heisenberg’s uncertainty principle, allowing perfect state discrimination and perfect cloning of coherent states. The model is extended to wave packets and smoothly recovers standard quantum mechanics in an appropriate physical limit. The analogy with general relativistic time dilation suggests that OTCs provide a novel alternative to existing proposals for the behavior of quantum systems under gravity.
Open timelike curves violate Heisenberg's uncertainty principle.
Pienaar, J L; Ralph, T C; Myers, C R
2013-02-08
Toy models for quantum evolution in the presence of closed timelike curves have gained attention in the recent literature due to the strange effects they predict. The circuits that give rise to these effects appear quite abstract and contrived, as they require nontrivial interactions between the future and past that lead to infinitely recursive equations. We consider the special case in which there is no interaction inside the closed timelike curve, referred to as an open timelike curve (OTC), for which the only local effect is to increase the time elapsed by a clock carried by the system. Remarkably, circuits with access to OTCs are shown to violate Heisenberg's uncertainty principle, allowing perfect state discrimination and perfect cloning of coherent states. The model is extended to wave packets and smoothly recovers standard quantum mechanics in an appropriate physical limit. The analogy with general relativistic time dilation suggests that OTCs provide a novel alternative to existing proposals for the behavior of quantum systems under gravity.
Incorporating Experience Curves in Appliance Standards Analysis
Energy Technology Data Exchange (ETDEWEB)
Garbesi, Karina; Chan, Peter; Greenblatt, Jeffery; Kantner, Colleen; Lekov, Alex; Meyers, Stephen; Rosenquist, Gregory; Buskirk, Robert Van; Yang, Hung-Chia; Desroches, Louis-Benoit
2011-10-31
The technical analyses in support of U.S. energy conservation standards for residential appliances and commercial equipment have typically assumed that manufacturing costs and retail prices remain constant during the projected 30-year analysis period. There is, however, considerable evidence that this assumption does not reflect real market prices. Costs and prices generally fall in relation to cumulative production, a phenomenon known as experience and modeled by a fairly robust empirical experience curve. Using price data from the Bureau of Labor Statistics, and shipment data obtained as part of the standards analysis process, we present U.S. experience curves for room air conditioners, clothes dryers, central air conditioners, furnaces, and refrigerators and freezers. These allow us to develop more representative appliance price projections than the assumption-based approach of constant prices. These experience curves were incorporated into recent energy conservation standards for these products. The impact on the national modeling can be significant, often increasing the net present value of potential standard levels in the analysis. In some cases a previously cost-negative potential standard level demonstrates a benefit when incorporating experience. These results imply that past energy conservation standards analyses may have undervalued the economic benefits of potential standard levels.
Prospects for PV: a learning curve analysis
International Nuclear Information System (INIS)
Zwaan, Bob van der; Rabi, A.
2003-01-01
This article gives an overview of the current state-of-the-art of photovoltaic electricity technology, and addresses its potential for cost reductions over the first few decades of the 21st century. Current PV production cost ranges are presented, both in terms of capacity installation and electricity generation, of single crystalline silicon, multi-crystalline silicon, amorphous silicon and other thin film technologies. Possible decreases of these costs are assessed, as expected according to the learning-curve methodology. We also estimate how much PV could gain if external costs (due to environmental and health damage) of energy were internalised, for example by an energy tax. Our conclusions are that, (1) mainly due its high costs, PV electricity is unlikely to play a major role in global energy supply and carbon emissions abatement before 2020, (2) extrapolating learning curves observed in the past, one can expect its costs to decrease significantly over the coming years, so that a considerable PV electricity share world-wide could materialise after 2020, (3) niche-market applications, e.g. using stand-alone systems in remote areas, are crucial for continuing 'the ride along the learning curve', (4) damage costs of conventional (fossil) power sources are considerable, and their internalisation would improve the competitiveness of PV, although probably not enough to close the current cost gap. (author)
Bayat, Hossein; Sedaghat, Azadeh; Safari Sinegani, Ali Akbar; Gregory, Andrew S.
2015-03-01
This study was conducted to estimate the soil unsaturated hydraulic conductivity through the van Genuchten model using easy to measure soil properties by regression and artificial neural networks methods. In this study, 148 soil samples were taken from five provinces of Iran. Basic soil properties (clay, silt/sand and bulk density) and other soil properties were measured. Soil water retention curve was measured to obtain the unsaturated hydraulic conductivity curve using the van Genuchten-Mualem model. Confined compression curve was measured and the modified model of van Genuchten was fitted on its data. Two-thirds and one-third of the data were used for the training and testing steps, respectively. Confined compression curve parameters and other soil properties were used as predictors to estimate unsaturated hydraulic conductivity curve. Pedotransfer functions (PTFs) were developed in two separate parts: in 5 and 6 PTFs basic soil properties were or were not used as predictors, respectively. The artificial neural networks (ANNs) performed better than the regression methods. Among the ANN-developed PTFs which have not used basic soil properties as predictors, PTFa3, with the inputs of the parameters of confined compression curve (n∗, α∗ and e0), performed better than the others. Also, among the ANN-developed PTFs that used basic soil properties as predictors along with the other input variables, PTFb5 that used the σmc (stress at the maximum curvature) and σi (stress at the inflection point) as inputs along with basic soil properties, performed better than the other PTFs. The results showed a successful prediction of the hydraulic conductivity curve using confined compression curve.
Polynuclear Aromatic Hydrocarbons with Curved Surfaces: Buckyballs
Energy Technology Data Exchange (ETDEWEB)
Sygula, Andrzej [Mississippi State Univ., Mississippi State, MS (United States)
2016-08-15
The discovery of a new allotropic form of elemental carbon – the fullerenes – and subsequently other novel forms of elemental carbon with pyramidalized surfaces, most notably single-walled and multi-walled carbon nanotubes, introduced a novel structural motif to the polycyclic aromatic hydrocarbons (PAHs) with nonplanar surfaces. Our research program supported by BES DOE grant DE-FG02-04ER15514 has dealt with the synthesis, structural studies, and chemistry of the novel curved-surface PAHs with carbon frameworks structurally related to fullerenes. They are referred to as “buckybowls”. We prepared several new buckybowls and, even more importantly, developed the efficient, gram-scale synthetic methodologies for the preparation of small buckybowls, most notably corannulene (C20H10) and its derivatives. In addition, the employment of the corannulene-based synthons previously developed in our laboratory led to a number of highly nonplanar molecular architectures with two or more corannulene subunits with a potential for the applications as novel materials in separation sciences, nanoelectronics, photovoltaics and catalysis. In collaboration with Professor Angelici (Iowa State) we prepared and characterized several transition metal complexes of corannulene, providing the first structural characterization of η6 metal complexes of buckybowls by a single crystal X-ray diffraction. In addition to the definitive structural characterization of the complexes we demonstrated that the (η6-C6Me6)Ru2+ unit in some relatively stable complexes activate the corannulene ligand to react with proper nucleophiles suggesting that such complexex may be used in catalysis. (Section C). We have explored the efficiency of the dispersion-based interactions of curved-surface conjugated carbon networks by high-level computational models. We showed that the curvature of such networks does not reduce the van der Waals attractions as compared to the planar systems of similar size. We than
Granados, I.; Calo, M.; Ramos, V.
2017-12-01
We developed a Matlab suite package (NDCP, Noisy Dispersion Curve Picking) that allows a full control over parameters to identify correctly group velocity dispersion curves in two types of datasets: correlograms between two stations or surface wave records from earthquakes. Using the frequency-time analysis (FTAN), the procedure to obtain the dispersion curves from records with a high noise level becomes difficult, and sometimes, the picked curve result in a misinterpreted character. For correlogram functions, obtained with cross-correlation of noise records or earthquake's coda, a non-homogeneous noise sources distribution yield to a non-symmetric Green's function (GF); to retrieve the complete information contained in there, NDCP allows to pick the dispersion curve in the time domain both in the causal and non-causal part of the GF. Then the picked dispersion curve is displayed on the FTAN diagram to in order to check if it matches with the maximum of the signal energy avoiding confusion with overtones or spike of noise. To illustrate how NDCP performs, we show exemple using: i) local correlograms functions obtained from sensors deployed into a volcanic caldera (Los Humeros, in Puebla, Mexico), ii) regional correlograms functions between two stations of the National Seismological Service (SSN, Servicio Sismológico Nacional in Spanish), and iii) surface wave seismic record for an earthquake located in the Pacific Ocean coast of Mexico and recorded by the SSN. This work is supported by the GEMEX project (Geothermal Europe-Mexico consortium).
Directory of Open Access Journals (Sweden)
Sylvie Troncale
Full Text Available MOTIVATION: Reverse phase protein array (RPPA is a powerful dot-blot technology that allows studying protein expression levels as well as post-translational modifications in a large number of samples simultaneously. Yet, correct interpretation of RPPA data has remained a major challenge for its broad-scale application and its translation into clinical research. Satisfying quantification tools are available to assess a relative protein expression level from a serial dilution curve. However, appropriate tools allowing the normalization of the data for external sources of variation are currently missing. RESULTS: Here we propose a new method, called NormaCurve, that allows simultaneous quantification and normalization of RPPA data. For this, we modified the quantification method SuperCurve in order to include normalization for (i background fluorescence, (ii variation in the total amount of spotted protein and (iii spatial bias on the arrays. Using a spike-in design with a purified protein, we test the capacity of different models to properly estimate normalized relative expression levels. The best performing model, NormaCurve, takes into account a negative control array without primary antibody, an array stained with a total protein stain and spatial covariates. We show that this normalization is reproducible and we discuss the number of serial dilutions and the number of replicates that are required to obtain robust data. We thus provide a ready-to-use method for reliable and reproducible normalization of RPPA data, which should facilitate the interpretation and the development of this promising technology. AVAILABILITY: The raw data, the scripts and the normacurve package are available at the following web site: http://microarrays.curie.fr.
Evaluation of Shape Parameter Effect on the J-R Curve of Curved CT Specimen Using Limit Load Method
Energy Technology Data Exchange (ETDEWEB)
Shin, In Hwan; Park, Chi Yong [Korea Hydro Nuclear Power Corporation, Seoul (Korea, Republic of); Seok, Chang Sung; Koo, Jae Mean [SungKyunKwan University, Suwon (Korea, Republic of)
2014-07-15
In this study, the effect of shape parameters on the J-R curves of curved CT specimens was evaluated using the limit load method. Fracture toughness tests considering the shape factors L/W and Rm/t of the specimens were also performed. Thereafter, the J-R curves of the curved CT specimens were compared using the J-integral equation proposed in the ASTM (American Society for Testing and Materials) and limit load solution. The J-R curves of the curved CT specimens were also compared with those of the CWP (curved wide plate), which is regarded to be similar to real pipe and standard specimens.. Finally, the effectiveness of the J-R curve of each curved CT specimen was evaluated. The results of this study can be used for assessing the applicability of curved CT specimens in the accurate evaluation of the fracture toughness of real pipes.
Gamma-Ray Light Curves from Pulsar Magnetospheres with Finite Conductivity
Harding, A. K.; Kalapotharakos, C.; Kazanas, D.; Contopoulos, I.
2012-01-01
The Fermi Large Area Telescope has provided an unprecedented database for pulsar emission studies that includes gamma-ray light curves for over 100 pulsars. Modeling these light curves can reveal and constrain the geometry of the particle accelerator, as well as the pulsar magnetic field structure. We have constructed 3D magnetosphere models with finite conductivity, that bridge the extreme vacuum and force-free solutions used in previous light curves modeling. We are investigating the shapes of pulsar gamma-ray light curves using these dissipative solutions with two different approaches: (l) assuming geometric emission patterns of the slot gap and outer gap, and (2) using the parallel electric field provided by the resistive models to compute the trajectories and . emission of the radiating particles. The light curves using geometric emission patterns show a systematic increase in gamma-ray peak phase with increasing conductivity, introducing a new diagnostic of these solutions. The light curves using the model electric fields are very sensitive to the conductivity but do not resemble the observed Fermi light curves, suggesting that some screening of the parallel electric field, by pair cascades not included in the models, is necessary
Aspects of quantum field theory in curved space-time
Energy Technology Data Exchange (ETDEWEB)
Fulling, S.A. (Texas A and M Univ., College Station, TX (USA). Dept. of Mathematics)
1989-01-01
The theory of quantum fields on curved spacetimes has attracted great attention since the discovery, by Stephen Hawking, of black-hole evaporation. It remains an important subject for the understanding of such contemporary topics as inflationary cosmology, quantum gravity and superstring theory. The topics covered include normal-mode expansions for a general elliptic operator, Fock space, the Casimir effect, the Klein 'paradox', particle definition and particle creation in expanding universes, asymptotic expansion of Green's functions and heat kernels, and renormalization of the stress tensor. (author).
Higher dimensional curved domain walls on Kähler surfaces
International Nuclear Information System (INIS)
Akbar, Fiki T.; Gunara, Bobby E.; Radjabaycolle, Flinn C.; Wijaya, Rio N.
2017-01-01
In this paper we study some aspects of curved BPS-like domain walls in higher dimensional gravity theory coupled to scalars where the scalars span a complex Kähler surface with scalar potential turned on. Assuming that a fake superpotential has a special form which depends on Kähler potential and a holomorphic function, we prove that BPS-like equations have a local unique solution. Then, we analyze the vacuum structure of the theory including their stability using dynamical system and their existence in ultraviolet-infrared regions using renormalization group flow.
Higher dimensional curved domain walls on Kähler surfaces
Energy Technology Data Exchange (ETDEWEB)
Akbar, Fiki T., E-mail: ftakbar@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Gunara, Bobby E., E-mail: bobby@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Radjabaycolle, Flinn C. [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia); Departement of Physics, Faculty of Mathematics and Natural Sciences, Cendrawasih University, Jl. Kampwolker Kampus Uncen Baru Waena-Jayapura 99351 (Indonesia); Wijaya, Rio N. [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10 Bandung, 40132 (Indonesia)
2017-03-15
In this paper we study some aspects of curved BPS-like domain walls in higher dimensional gravity theory coupled to scalars where the scalars span a complex Kähler surface with scalar potential turned on. Assuming that a fake superpotential has a special form which depends on Kähler potential and a holomorphic function, we prove that BPS-like equations have a local unique solution. Then, we analyze the vacuum structure of the theory including their stability using dynamical system and their existence in ultraviolet-infrared regions using renormalization group flow.
Aspects of quantum field theory in curved space-time
International Nuclear Information System (INIS)
Fulling, S.A.
1989-01-01
The theory of quantum fields on curved spacetimes has attracted great attention since the discovery, by Stephen Hawking, of black-hole evaporation. It remains an important subject for the understanding of such contemporary topics as inflationary cosmology, quantum gravity and superstring theory. The topics covered include normal-mode expansions for a general elliptic operator, Fock space, the Casimir effect, the Klein 'paradox', particle definition and particle creation in expanding universes, asymptotic expansion of Green's functions and heat kernels, and renormalization of the stress tensor. (author)