Methods for Performing Survival Curve Quality-of-Life Assessments.
Sumner, Walton; Ding, Eric; Fischer, Irene D; Hagen, Michael D
2014-08-01
Many medical decisions involve an implied choice between alternative survival curves, typically with differing quality of life. Common preference assessment methods neglect this structure, creating some risk of distortions. Survival curve quality-of-life assessments (SQLA) were developed from Gompertz survival curves fitting the general population's survival. An algorithm was developed to generate relative discount rate-utility (DRU) functions from a standard survival curve and health state and an equally attractive alternative curve and state. A least means squared distance algorithm was developed to describe how nearly 3 or more DRU functions intersect. These techniques were implemented in a program called X-Trade and tested. SQLA scenarios can portray realistic treatment choices. A side effect scenario portrays one prototypical choice, to extend life while experiencing some loss, such as an amputation. A risky treatment scenario portrays procedures with an initial mortality risk. A time trade scenario mimics conventional time tradeoffs. Each SQLA scenario yields DRU functions with distinctive shapes, such as sigmoid curves or vertical lines. One SQLA can imply a discount rate or utility if the other value is known and both values are temporally stable. Two SQLA exercises imply a unique discount rate and utility if the inferred DRU functions intersect. Three or more SQLA results can quantify uncertainty or inconsistency in discount rate and utility estimates. Pilot studies suggested that many subjects could learn to interpret survival curves and do SQLA. SQLA confuse some people. Compared with SQLA, standard gambles quantify very low utilities more easily, and time tradeoffs are simpler for high utilities. When discount rates approach zero, time tradeoffs are as informative and easier to do than SQLA. SQLA may complement conventional utility assessment methods. © The Author(s) 2014.
Capability curve analysis of photovoltaic generation systems
Cabrera Tobar, Ana; Bullich Massagué, Eduard; Aragüés Peñalba, Mònica; Gomis Bellmunt, Oriol
2016-01-01
The present article assesses the study of the PV generator capability curves for use in large scale photovoltaic power plants (LS-PVPPs). For this purpose, the article focuses on three main aspects: (i) the modelling of the main components of the PV generator, (ii) the operational limits analysis of the PV array together with the inverter, and (iii) the capability curve analysis considering variable solar irradiance and temperature. To validate this study a PVPP of 1 MW is designed, modelled ...
Comparing survival curves using rank tests
Albers, Willem/Wim
1990-01-01
Survival times of patients can be compared using rank tests in various experimental setups, including the two-sample case and the case of paired data. Attention is focussed on two frequently occurring complications in medical applications: censoring and tail alternatives. A review is given of the
Multivariate permutation test to compare survival curves for matched data
National Research Council Canada - National Science Library
Galimberti, Stefania; Valsecchi, Maria Grazia
2013-01-01
... for the comparison of survival curves cannot be applied in this setting. We demonstrate the validity of the proposed method with simulations, and we illustrate its application to data from an observational study for the comparison of bone marrow transplantation and chemotherapy in the treatment of paediatric leukaemia. The use of the multivariate permutation testing approach is recommended in the highly stratified context of survival matched data, especially when the proportional hazards assumption does not hold.
Individual survival curves comparing subjective and observed mortality risks.
Bissonnette, Luc; Hurd, Michael D; Michaud, Pierre-Carl
2017-12-01
We compare individual survival curves constructed from objective (actual mortality) and elicited subjective information (probability of survival to a given target age). We develop a methodology to estimate jointly subjective and objective individual survival curves accounting for rounding on subjective reports of perceived survival. We make use of the long follow-up period in the Health and Retirement Study and the high quality of mortality data to estimate individual survival curves that feature both observed and unobserved heterogeneity. This allows us to compare objective and subjective estimates of remaining life expectancy for various groups and compare welfare effects of objective and subjective mortality risk using the life cycle model of consumption. We find that subjective and objective hazards are not the same. The median welfare loss from misperceptions of mortality risk when annuities are not available is 7% of current wealth at age 65 whereas more than 25% of respondents have losses larger than 60% of wealth. When annuities are available and exogenously given, the welfare loss is substantially lower. Copyright © 2017 John Wiley & Sons, Ltd.
National Research Council Canada - National Science Library
Guyot, Patricia; Ades, A E; Ouwens, Mario J N M; Welton, Nicky J
2012-01-01
.... In order to enhance the quality of secondary data analyses, we propose a method which derives from the published Kaplan Meier survival curves a close approximation to the original individual patient...
ON THE TOPOLOGY OF MECHANISMS DESIGNED FOR CURVES GENERATION
Directory of Open Access Journals (Sweden)
MEREUTA Elena
2008-07-01
Full Text Available The paper presents some mechanisms used for generating simple or complex curves. The mechanisms are shown in different positions and for some special curves the demonstrations are performed.
Graphing survival curve estimates for time-dependent covariates.
Schultz, Lonni R; Peterson, Edward L; Breslau, Naomi
2002-01-01
Graphical representation of statistical results is often used to assist readers in the interpretation of the findings. This is especially true for survival analysis where there is an interest in explaining the patterns of survival over time for specific covariates. For fixed categorical covariates, such as a group membership indicator, Kaplan-Meier estimates (1958) can be used to display the curves. For time-dependent covariates this method may not be adequate. Simon and Makuch (1984) proposed a technique that evaluates the covariate status of the individuals remaining at risk at each event time. The method takes into account the change in an individual's covariate status over time. The survival computations are the same as the Kaplan-Meier method, in that the conditional survival estimates are the function of the ratio of the number of events to the number at risk at each event time. The difference between the two methods is that the individuals at risk within each level defined by the covariate is not fixed at time 0 in the Simon and Makuch method as it is with the Kaplan-Meier method. Examples of how the two methods can differ for time dependent covariates in Cox proportional hazards regression analysis are presented.
Research of Cubic Bezier Curve NC Interpolation Signal Generator
Directory of Open Access Journals (Sweden)
Shijun Ji
2014-08-01
Full Text Available Interpolation technology is the core of the computer numerical control (CNC system, and the precision and stability of the interpolation algorithm directly affect the machining precision and speed of CNC system. Most of the existing numerical control interpolation technology can only achieve circular arc interpolation, linear interpolation or parabola interpolation, but for the numerical control (NC machining of parts with complicated surface, it needs to establish the mathematical model and generate the curved line and curved surface outline of parts and then discrete the generated parts outline into a large amount of straight line or arc to carry on the processing, which creates the complex program and a large amount of code, so it inevitably introduce into the approximation error. All these factors affect the machining accuracy, surface roughness and machining efficiency. The stepless interpolation of cubic Bezier curve controlled by analog signal is studied in this paper, the tool motion trajectory of Bezier curve can be directly planned out in CNC system by adjusting control points, and then these data were put into the control motor which can complete the precise feeding of Bezier curve. This method realized the improvement of CNC trajectory controlled ability from the simple linear and circular arc to the complex project curve, and it provides a new way for economy realizing the curve surface parts with high quality and high efficiency machining.
A New Path Generation Algorithm Based on Accurate NURBS Curves
Sawssen Jalel; Philippe Marthon; Atef Hamouda
2016-01-01
The process of finding an optimum, smooth and feasible global path for mobile robot navigation usually involves determining the shortest polyline path, which will be subsequently smoothed to satisfy the requirements. Within this context, this paper deals with a novel roadmap algorithm for generating an optimal path in terms of Non-Uniform Rational B-Splines (NURBS) curves. The generated path is well constrained within the curvature limit by exploiting the influence of the weight parameter of ...
PLANAR MECHANISMS USED FOR GENERATING CURVE LINE TRANSLATION MOTION
Directory of Open Access Journals (Sweden)
Ovidiu ANTONESCU
2015-05-01
Full Text Available The curve line translation motion can be generated in the particular form of the circular translation, through mono-mobile mechanisms with articulated links of simple parallelogram type (with a fixed side or through transmission with toothed belt with a fixed wheel. Also, the circular translation can be generated through planar mechanisms with two cylindrical gears with a fixed central wheel. It is mentioned that the two cylindrical gearings of the Fergusson mechanisms are both exterior and interior.
Three-generation neutrino oscillations in curved spacetime
Energy Technology Data Exchange (ETDEWEB)
Zhang, Yu-Hao, E-mail: yhzhang1994@gmail.com; Li, Xue-Qian, E-mail: lixq@nankai.edu.cn
2016-10-15
Three-generation MSW effect in curved spacetime is studied and a brief discussion on the gravitational correction to the neutrino self-energy is given. The modified mixing parameters and corresponding conversion probabilities of neutrinos after traveling through celestial objects of constant densities are obtained. The method to distinguish between the normal hierarchy and inverted hierarchy is discussed in this framework. Due to the gravitational redshift of energy, in some extreme situations, the resonance energy of neutrinos might be shifted noticeably and the gravitational effect on the self-energy of neutrino becomes significant at the vicinities of spacetime singularities.
A New Path Generation Algorithm Based on Accurate NURBS Curves
Directory of Open Access Journals (Sweden)
Sawssen Jalel
2016-04-01
Full Text Available The process of finding an optimum, smooth and feasible global path for mobile robot navigation usually involves determining the shortest polyline path, which will be subsequently smoothed to satisfy the requirements. Within this context, this paper deals with a novel roadmap algorithm for generating an optimal path in terms of Non-Uniform Rational B-Splines (NURBS curves. The generated path is well constrained within the curvature limit by exploiting the influence of the weight parameter of NURBS and/or the control points' locations. The novelty of this paper lies in the fact that NURBS curves are not used only as a means of smoothing, but they are also involved in meeting the system's constraints via a suitable parameterization of the weights and locations of control points. The accurate parameterization of weights allows for a greater benefit to be derived from the influence and geometrical effect of this factor, which has not been well investigated in previous works. The effectiveness of the proposed algorithm is demonstrated through extensive MATLAB computer simulations.
Stavrev, Pavel; Stavreva, Nadejda; Ruggieri, Ruggero; Nahum, Alan
2015-08-07
We have compared two methods of estimating the cellular radiosensitivity of a heterogeneous tumour, namely, via cell-survival and via tumour control probability (TCP) pseudo-experiments. It is assumed that there exists intra-tumour variability in radiosensitivity and that the tumour consists predominantly of radiosensitive cells and a small number of radio-resistant cells.Using a multi-component, linear-quadratic (LQ) model of cell kill, a pseudo-experimental cell-survival versus dose curve is derived. This curve is then fitted with a mono-component LQ model describing the response of a homogeneous cell population. For the assumed variation in radiosensitivity it is shown that the composite pseudo-experimental survival curve is well approximated by the survival curve of cells with uniform radiosensitivity.For the same initial cell radiosensitivity distribution several pseudo-experimental TCP curves are simulated corresponding to different fractionation regimes. The TCP model used accounts for clonogen proliferation during a fractionated treatment. The set of simulated TCP curves is then fitted with a mono-component TCP model. As in the cell survival experiment the fit with a mono-component model assuming uniform radiosensitivity is shown to be highly acceptable.However, the best-fit values of cellular radiosensitivity produced via the two methods are very different. The cell-survival pseudo-experiment yields a high radiosensitivity value, while the TCP pseudo-experiment shows that the dose-response is dominated by the most resistant sub-population in the tumour, even when this is just a small fraction of the total.
Longevity and survival curves of Rhinella icterica (Anura, Bufonidae) under laboratory conditions.
Lima, M S C S; Pederassi, J; Souza, C A S
2014-05-01
Life tables and survival curves of tadpoles from Rhinella icterica species were studied in the laboratory, under abiotic conditions controlled by a purification filter, a timer and a chiller. The survival curve for larval stage confirms a great mortality trend in the initial stages, which decreases when reaching the mature morphological condition (r = -0.94). Stages 37, 38, 39, 40 and 41 showed gradual values for their age structures, while stages 42, 43 and 44 presented high variations. Based on the results under laboratory conditions, it can be concluded that the maturity of R. icterica tadpoles development between 37 and 44 stages has a negative correlation and their predicted life expectancy is a logarithmic growth curve (y=-761.96Ln(x)+5298.5).
Toward computer simulation of high-LET in vitro survival curves
Heuskin, A.-C.; Michiels, C.; Lucas, S.
2013-09-01
We developed a Monte Carlo based computer program called MCSC (Monte Carlo Survival Curve) able to predict the survival fraction of cells irradiated in vitro with a broad beam of high linear energy transfer particles. Three types of cell responses are studied: the usual high dose response, the bystander effect and the low-dose hypersensitivity (HRS). The program models the broad beam irradiation and double strand break distribution following Poisson statistics. The progression of cells through the cell cycle is taken into account while the repair takes place. Input parameters are experimentally determined for A549 lung carcinoma cells irradiated with 10 and 20 keV µm-1 protons, 115 keV µm-1 alpha particles and for EAhy926 endothelial cells exposed to 115 keV µm-1 alpha particles. Results of simulations are presented and compared with experimental survival curves obtained for A549 and EAhy296 cells. Results are in good agreement with experimental data for both cell lines and all irradiation protocols. The benefits of MCSC are several: the gain of time that would have been spent performing time-consuming clonogenic assays, the capacity to estimate survival fraction of cell lines not forming colonies and possibly the evaluation of radiosensitivity parameters of given individuals.
Collisions in Fast Generation of Ideal Classes and Points on Hyperelliptic and Elliptic Curves
DEFF Research Database (Denmark)
Lange, Tanja; Shparlinski, Igor
2005-01-01
Koblitz curves have been proposed to quickly generate random ideal classes and points on hyperelliptic and elliptic curves. To obtain a further speed-up a different way of generating these random elements has recently been proposed. In this paper we give an upper bound on the number of collisions...
ANTEROCOD: actuarial survival curves applied to medical coding support for chronic diseases.
Lecornu, L; Le Guillou, C; Le Saux, F; Hubert, M; Puentes, J; Cauvin, J M
2010-01-01
For the practitioner, choosing diagnosis codes is a non-intuitive operation. Mistakes are frequent, causing severe consequences on healthcare performance evaluation and funding. French physicians have to assign a code to all their activities and are frequently prone to these errors. Given that most of the time and particularly for chronic diseases indexed information is already available, we propose a tool named AnterOcod, in order to support the medical coding task. It suggests the list of most relevant plausible codes, predicted from the patient's earlier hospital stays, according to a set of previously utilized diagnosis codes. Our method applies the estimation of code reappearance rates, based on an equivalent approach to actuarial survival curves. Around 33% of the expected correct diagnosis codes were retrieved in this manner, after evaluating 998 discharge abstracts, significantly improving the coding task.
Supply Curves for Solar PV-Generated Electricity for the United States
Energy Technology Data Exchange (ETDEWEB)
Denholm, P.; Margolis, R.
2008-11-01
Energy supply curves attempt to estimate the relationship between the cost of an energy resource and the amount of energy available at or below that cost. In general, an energy supply curve is a series of step functions with each step representing a particular group or category of energy resource. The length of the step indicates how much of that resource is deployable or accessible at a given cost. Energy supply curves have been generated for a number of renewable energy sources including biomass fuels and geothermal, as well as conservation technologies. Generating a supply curve for solar photovoltaics (PV) has particular challenges due to the nature of the resource. The United States has a massive solar resource base -- many orders of magnitude greater than the total consumption of energy. In this report, we examine several possible methods for generating PV supply curves based exclusively on rooftop deployment.
Directory of Open Access Journals (Sweden)
Jonas Kalderstam
Full Text Available We investigate a new method to place patients into risk groups in censored survival data. Properties such as median survival time, and end survival rate, are implicitly improved by optimizing the area under the survival curve. Artificial neural networks (ANN are trained to either maximize or minimize this area using a genetic algorithm, and combined into an ensemble to predict one of low, intermediate, or high risk groups. Estimated patient risk can influence treatment choices, and is important for study stratification. A common approach is to sort the patients according to a prognostic index and then group them along the quartile limits. The Cox proportional hazards model (Cox is one example of this approach. Another method of doing risk grouping is recursive partitioning (Rpart, which constructs a decision tree where each branch point maximizes the statistical separation between the groups. ANN, Cox, and Rpart are compared on five publicly available data sets with varying properties. Cross-validation, as well as separate test sets, are used to validate the models. Results on the test sets show comparable performance, except for the smallest data set where Rpart's predicted risk groups turn out to be inverted, an example of crossing survival curves. Cross-validation shows that all three models exhibit crossing of some survival curves on this small data set but that the ANN model manages the best separation of groups in terms of median survival time before such crossings. The conclusion is that optimizing the area under the survival curve is a viable approach to identify risk groups. Training ANNs to optimize this area combines two key strengths from both prognostic indices and Rpart. First, a desired minimum group size can be specified, as for a prognostic index. Second, the ability to utilize non-linear effects among the covariates, which Rpart is also able to do.
Kalderstam, Jonas; Edén, Patrik; Ohlsson, Mattias
2015-01-01
We investigate a new method to place patients into risk groups in censored survival data. Properties such as median survival time, and end survival rate, are implicitly improved by optimizing the area under the survival curve. Artificial neural networks (ANN) are trained to either maximize or minimize this area using a genetic algorithm, and combined into an ensemble to predict one of low, intermediate, or high risk groups. Estimated patient risk can influence treatment choices, and is important for study stratification. A common approach is to sort the patients according to a prognostic index and then group them along the quartile limits. The Cox proportional hazards model (Cox) is one example of this approach. Another method of doing risk grouping is recursive partitioning (Rpart), which constructs a decision tree where each branch point maximizes the statistical separation between the groups. ANN, Cox, and Rpart are compared on five publicly available data sets with varying properties. Cross-validation, as well as separate test sets, are used to validate the models. Results on the test sets show comparable performance, except for the smallest data set where Rpart's predicted risk groups turn out to be inverted, an example of crossing survival curves. Cross-validation shows that all three models exhibit crossing of some survival curves on this small data set but that the ANN model manages the best separation of groups in terms of median survival time before such crossings. The conclusion is that optimizing the area under the survival curve is a viable approach to identify risk groups. Training ANNs to optimize this area combines two key strengths from both prognostic indices and Rpart. First, a desired minimum group size can be specified, as for a prognostic index. Second, the ability to utilize non-linear effects among the covariates, which Rpart is also able to do.
Cooperative equilibrium curves generated by ordered ligand binding to multi-site molecules.
Michel, Denis
2007-09-01
The sigmoid shape of equilibrium curves in normal axes and Hill coefficients higher than unity, are indexes of cooperativity or homotropic allostery where the affinity for the ligand increases as saturation progresses. The mathematical transformation of the Adair scheme of equilibria in the Hill plot, reveals that sigmoid binding curves can also be generated by ordered ligand binding to a receptor with multiple binding sites of identical microscopic association constants. This mechanism only based on the law of mass action, could participate to some extent to certain cooperative effects observed in non-biological systems and perhaps in the physiological binding of oxygen to heme proteins.
Generators for the l-torsion subgroup of Jacobians of Genus Two Curves
DEFF Research Database (Denmark)
Ravnshøj, Christian Robenhagen
2008-01-01
We give an explicit description of the matrix representation of the Frobenius endomorphism on the Jacobian of a genus two curve on the subgroup of l-torsion points. By using this description, we can describe the matrix representation of the Weil-pairing on the subgroup of l-torsion points...... explicitly. Finally, the explicit description of the Weil-pairing provides us with an efficient, probabilistic algorithm to find generators of the subgroup of l-torsion points on the Jacobian of a genus two curve....
Kim, Fernando J; Sehrt, David; Pompeo, Alexandre; Molina, Wilson R
2014-05-01
To characterize laparoscopic ultrasonic dissector surgical plume emission (laminar or turbulent) and investigate plume settlement time between curved and straight blades. A straight and a curved blade laparoscopic ultrasonic dissector were activated on tissue and in a liquid environment to evaluate plume emission. Plume emission was characterized as either laminar or turbulent and the plume settlement times were compared. Devices were then placed in liquid to observed consistency in the fluid disruption. Two types of plume emission were identified generating different directions of plume: laminar flow causes minimal visual obstruction by directing the aerosol downwards, while turbulent flow directs plume erratically across the cavity. Laminar plume dissipates immediately while turbulent plume reaches a second maximum obstruction approximately 0.3 s after activation and clears after 2 s. Turbulent plume was observed with the straight blade in 10 % of activations, and from the curved blade in 47 % of activations. The straight blade emitted less obstructive plume. Turbulent flow is disruptive to laparoscopic visibility with greater field obstruction and requires longer settling than laminar plume. Ultrasonic dissectors with straight blades have more consistent oscillations and generate more laminar flow compared with curved blades. Surgeons may avoid laparoscope smearing from maximum plume generation depending on blade geometry.
Generation of R-Curve from 4ENF Specimens: An Experimental Study
Directory of Open Access Journals (Sweden)
V. Alfred Franklin
2014-01-01
Full Text Available The experimental determination of the resistance to delamination is very important in aerospace applications as composite materials have superior properties only in the fiber direction. To measure the interlaminar fracture toughness of composite materials, different kinds of specimens and experimental methods are available. This article examines the fracture energy of four-point end-notched flexure (4ENF composite specimens made of carbon/epoxy and glass/epoxy. Experiments were conducted on these laminates and the mode II fracture energy, GIIC, was evaluated using compliance method and was compared with beam theory solution. The crack growth resistance curve (R-curve for these specimens was generated and the found glass/epoxy shows higher toughness values than carbon/epoxy composite. From this study, it was observed that R-curve effect in 4ENF specimens is quite mild, which means that the measured delamination toughness, GIIC, is more accurate.
Meshram, S. Gajbhiye; Sharma, S. K.; Tignath, S.
2017-07-01
Watershed is an ideal unit for planning and management of land and water resources (Gajbhiye et al., IEEE international conference on advances in technology and engineering (ICATE), Bombay, vol 1, issue 9, pp 23-25, 2013a; Gajbhiye et al., Appl Water Sci 4(1):51-61, 2014a; Gajbhiye et al., J Geol Soc India (SCI-IF 0.596) 84(2):192-196, 2014b). This study aims to generate the curve number, using remote sensing and geographical information system (GIS) and the effect of slope on curve number values. The study was carried out in Kanhaiya Nala watershed located in Satna district of Madhya Pradesh. Soil map, Land Use/Land cover and slope map were generated in GIS Environment. The CN parameter values corresponding to various soil, land cover, and land management conditions were selected from Natural Resource Conservation Service (NRCS) standard table. Curve number (CN) is an index developed by the NRCS, to represent the potential for storm water runoff within a drainage area. The CN for a drainage basin is estimated using a combination of land use, soil, and antecedent soil moisture condition (AMC). In present study effect of slope on CN values were determined. The result showed that the CN unadjusted value are higher in comparison to CN adjusted with slope. Remote sensing and GIS is very reliable technique for the preparation of most of the input data required by the SCS curve number model.
Statistically Generated Weighted Curve Fit of Residual Functions for Modal Analysis of Structures
Directory of Open Access Journals (Sweden)
Paul Stanley Bookout
1997-01-01
Full Text Available A statistically generated weighting function for a second-order polynomial curve fit of residual functions has been developed. The residual flexibility test method, from which a residual function is generated, is a procedure to modal test large structures in a free-free environment to measure the effects of higher order modes and stiffness at distinct degree of freedom interfaces. Due to the present damping estimate limitations in the modal parameter evaluation (natural frequencies and mode shapes of test data, the residual function has regions of irregular data, which should be a smooth curve in a second-order polynomial form. A weighting function of the data is generated by examining the variances between neighboring data points. From a weighted second-order polynomial curve fit, an accurate residual flexibility value can be obtained. The residual flexibility value and free-free modes from testing are used to improve a mathematical model of the structure, which is used to predict constrained mode shapes.
Why the Kantian ideal survives medical learning curves, and why it matters.
Brecher, B
2006-09-01
The "Kantian ideal" is often misunderstood as invoking individual autonomy rather than rational self legislation. Le Morvan and Stock's otherwise insightful discussion of "Medical learning curves and the Kantian ideal"--for example--draws the mistaken inference that that ideal is inconsistent with the realities of medical practice. But it is not. Rationally to be a patient entails accepting its necessary conditions.
DEFF Research Database (Denmark)
Klein, John P.; Keiding, Niels; Shu, Youyi
2000-01-01
CML, donor lymphocyte infusion, leukaemia-free survival, current leukaemia-free survival, statistical methods......CML, donor lymphocyte infusion, leukaemia-free survival, current leukaemia-free survival, statistical methods...
Arbulú, Italo; Lozano, Javier; Rey-Maquieira, Javier
2015-12-01
The relationship between tourism growth and municipal solid waste (MSW) generation has been, until now, the subject of little research. This is puzzling since the tourism sector is an important MSW generator and, at the same time, is willing to avoid negative impacts from MSW mismanagement. This paper aims to provide tools for tourism and MSW management by assessing the effects of tourism volume, tourism quality and tourism specialization on MSW generation in the UE. This is done using the Environmental Kuznets Curve (EKC) framework. The study considers a panel data for 32 European economies in the 1997-2010 periods. Empirical results support the EKC hypothesis for MSW and shows that northern countries tend to have lower income elasticity than less developed countries; furthermore, results confirm a non-linear and significant effect of tourism arrivals, expenditure per tourist and tourism specialization on MSW generation. Copyright © 2015 Elsevier Ltd. All rights reserved.
Practical Constraint K-Segment Principal Curve Algorithms for Generating Railway GPS Digital Map
Directory of Open Access Journals (Sweden)
Dewang Chen
2013-01-01
Full Text Available In order to obtain a decent trade-off between the low-cost, low-accuracy Global Positioning System (GPS receivers and the requirements of high-precision digital maps for modern railways, using the concept of constraint K-segment principal curves (CKPCS and the expert knowledge on railways, we propose three practical CKPCS generation algorithms with reduced computational complexity, and thereafter more suitable for engineering applications. The three algorithms are named ALLopt, MPMopt, and DCopt, in which ALLopt exploits global optimization and MPMopt and DCopt apply local optimization with different initial solutions. We compare the three practical algorithms according to their performance on average projection error, stability, and the fitness for simple and complex simulated trajectories with noise data. It is found that ALLopt only works well for simple curves and small data sets. The other two algorithms can work better for complex curves and large data sets. Moreover, MPMopt runs faster than DCopt, but DCopt can work better for some curves with cross points. The three algorithms are also applied in generating GPS digital maps for two railway GPS data sets measured in Qinghai-Tibet Railway (QTR. Similar results like the ones in synthetic data are obtained. Because the trajectory of a railway is relatively simple and straight, we conclude that MPMopt works best according to the comprehensive considerations on the speed of computation and the quality of generated CKPCS. MPMopt can be used to obtain some key points to represent a large amount of GPS data. Hence, it can greatly reduce the data storage requirements and increase the positioning speed for real-time digital map applications.
Directory of Open Access Journals (Sweden)
Seyed M.H. NABAVI
2015-05-01
Full Text Available One of the most important subjects in power systems is an optimal and economic design of power transformers. In this paper, determination of turn ratios for power transformers that are directly connected to generators is evaluated considering reactive power generation and its impact on the optimal turn ratio selection. A generator capability curve has been used to explain all details. Three different methods have been examined and the simulation results have been compared in a real test system, on Rudbar-Lorestan, Karkheh, Karoon 3, Masjed Solayman, and Gotvand hydro power plants. The obtained results illustrate that without considering limits of reactive power the achieved turn ratios can be much higher than the optimal values.
Ramanathan, Karthik Narayan
Quantitative and qualitative assessment of the seismic risk to highway bridges is crucial in pre-earthquake planning, and post-earthquake response of transportation systems. Such assessments provide valuable knowledge about a number of principal effects of earthquakes such as traffic disruption of the overall highway system, impact on the regions’ economy and post-earthquake response and recovery, and more recently serve as measures to quantify resilience. Unlike previous work, this study captures unique bridge design attributes specific to California bridge classes along with their evolution over three significant design eras, separated by the historic 1971 San Fernando and 1989 Loma Prieta earthquakes (these events affected changes in bridge seismic design philosophy). This research developed next-generation fragility curves for four multispan concrete bridge classes by synthesizing new knowledge and emerging modeling capabilities, and by closely coordinating new and ongoing national research initiatives with expertise from bridge designers. A multi-phase framework was developed for generating fragility curves, which provides decision makers with essential tools for emergency response, design, planning, policy support, and maximizing investments in bridge retrofit. This framework encompasses generational changes in bridge design and construction details. Parameterized high-fidelity three-dimensional nonlinear analytical models are developed for the portfolios of bridge classes within different design eras. These models incorporate a wide range of geometric and material uncertainties, and their responses are characterized under seismic loadings. Fragility curves were then developed considering the vulnerability of multiple components and thereby help to quantify the performance of highway bridge networks and to study the impact of seismic design principles on the performance within a bridge class. This not only leads to the development of fragility relations
Spline Trajectory Algorithm Development: Bezier Curve Control Point Generation for UAVs
Howell, Lauren R.; Allen, B. Danette
2016-01-01
A greater need for sophisticated autonomous piloting systems has risen in direct correlation with the ubiquity of Unmanned Aerial Vehicle (UAV) technology. Whether surveying unknown or unexplored areas of the world, collecting scientific data from regions in which humans are typically incapable of entering, locating lost or wanted persons, or delivering emergency supplies, an unmanned vehicle moving in close proximity to people and other vehicles, should fly smoothly and predictably. The mathematical application of spline interpolation can play an important role in autopilots' on-board trajectory planning. Spline interpolation allows for the connection of Three-Dimensional Euclidean Space coordinates through a continuous set of smooth curves. This paper explores the motivation, application, and methodology used to compute the spline control points, which shape the curves in such a way that the autopilot trajectory is able to meet vehicle-dynamics limitations. The spline algorithms developed used to generate these curves supply autopilots with the information necessary to compute vehicle paths through a set of coordinate waypoints.
Design Curve Generation for 3D SiC Fiber Architecture
Lang, Jerry; Dicarlo, James A.
2014-01-01
The design tool provides design curves that allow a simple and quick way to examine multiple factors that can influence the processing and key properties of the preforms and their final SiC-reinforced ceramic composites without over obligating financial capital for the fabricating of materials. Tool predictions for process and fiber fraction properties have been validated for a HNS 3D preform.The virtualization aspect of the tool will be used to provide a quick generation of solid models with actual fiber paths for finite element evaluation to predict mechanical and thermal properties of proposed composites as well as mechanical displacement behavior due to creep and stress relaxation to study load sharing characteristic between constitutes for better performance.Tool predictions for the fiber controlled properties of the SiCSiC CMC fabricated from the HNS preforms will be valuated and up-graded from the measurements on these CMC
A simple technique to generate in-plane forming limit curves and selected applications
Raghavan, K. S.
1995-08-01
A simple technique to generate in-plane forming limit curves has been developed. This technique is based on the Marciniak biaxial stretch test using a single punch/die configuration, but the specimen and washer geometries have been modified in order to achieve failure in both drawing and stretching deformation modes. The experimental technique is described, and the advantages of using this inplane method over the conventional out-of-plane dome method are discussed. It is shown that (a) sheet thickness has an intrinsic influence on forming limits that is not related to small bending strain variations with thickness or to deformation in the presence of friction and curvature, (b) plastic anisotropy (bar r value) does not substantially affect forming limits, and (c) in-plane forming limits are slightly lower (5 to 6 pct) than out-of-plane forming limits near plane strain; these differences are smaller than previously reported values (12 to 15 pct) in the literature.
Energy Technology Data Exchange (ETDEWEB)
Barros, Thaisa C. de; Castrillo, Lazara S.; Xavier, Aline G.; Goncalves, Gabriela de L.; Melo, Julio Angelo, E-mail: barros.camara@gmail.com, E-mail: lazaracastrillo@hotmail.com, E-mail: alinegxavier@gmail.com, E-mail: gabilimag_@hotmail.com, E-mail: angelo_mecanic@hotmail.com [Escola Politecnica de Pernambuco (UPE), Recife, PE (Brazil). Departamento de Engenharia Mecanica Industrial
2017-11-01
To meet the demand for electric consumption, it is fundamental to prepare an efficient energy planning that guarantees the safe supply of energy, so that the price of kilowatt-hours for the consumer respects the tariff modality and the socio-environmental impact is the smallest possible. In recent years, alternative sources of energy have been gaining considerable space in the Brazilian generating park. Among the many options for energy supply, choosing the most feasible involves the use of techniques that compare all the costs involved in generating electricity from the sources available in the Brazilian energy matrix. The objective of the work is to show a quick, practical and objective tool that performs this comparison and assists in decision making. The method based on the comparison is the Cost of Energy and the tool for the application of the same are the Screening curves, widely used by the International Atomic Energy Agency (IAEA). In this analysis, the following parameters are considered: operating capacity, toxic gas emission rate, fuel consumption and values, fixed and variable costs of operation and maintenance, investment values for each source, construction time and useful life. It is worth noting that the method does not consider in calculations aspects such as inflation, forced interruptions of the plant and other more specific factors. With the work, it was possible to perform an examination of the costs of the generation technologies available in Brazil and, through the obtained data, the economic viability of the generating parks was discussed through simulations in different scenarios, comparing the sources among themselves. (author)
Pseudorandom Bit Sequence Generator for Stream Cipher Based on Elliptic Curves
Directory of Open Access Journals (Sweden)
Jilna Payingat
2015-01-01
Full Text Available This paper proposes a pseudorandom sequence generator for stream ciphers based on elliptic curves (EC. A detailed analysis of various EC based random number generators available in the literature is done and a new method is proposed such that it addresses the drawbacks of these schemes. Statistical analysis of the proposed method is carried out using the NIST (National Institute of Standards and Technology test suite and it is seen that the sequence exhibits good randomness properties. The linear complexity analysis shows that the system has a linear complexity equal to the period of the sequence which is highly desirable. The statistical complexity and security against known plain text attack are also analysed. A comparison of the proposed method with other EC based schemes is done in terms of throughput, periodicity, and security, and the proposed method outperforms the methods in the literature. For resource constrained applications where a highly secure key exchange is essential, the proposed method provides a good option for encryption by time sharing the point multiplication unit for EC based key exchange. The algorithm and architecture for implementation are developed in such a way that the hardware consumed in addition to point multiplication unit is much less.
Karahroudi, Mahdi Khodadadi; Parmoon, Bahman; Qasemi, Mohammadreza; Mobashery, Abolhasan; Saghafifar, Hossein
2017-07-20
Perfect optical vortices (POVs) are beams whose topological charges are independent of radius, unlike conventional optical vortices. POVs are the Fourier transformation of Bessel-Gaussian (BG) beams and can be seen in the far-field diffraction of BG beams. In this paper, we present the generation of POVs of arbitrary charge using curved fork grating (CFG) illuminated by BG beam. For this purpose, first, a theoretical study of the Fresnel-Kirchhoff integral for diffraction of a BG beam by CFG is completed. The analytical results show the presence of vortex beams with various topological charges in diffraction orders. Then, diffraction of the BG beam with the order (l) by CFG with a topological charge (p) is numerically simulated. Additionally, experimental results prove the generation of POVs in diffraction orders. Also, experimental interference patterns obtained by interfering a POV and Gaussian beam confirm the ability of analytical solutions to determine the topological charges of vortex beams. Comparison of the results reveals the validity of the analytical, simulation, and experimental results.
Poltorakov, A P
2001-01-01
We have continued an analysis of survival curves by the model of the vital receptors (MVR). The main types survival function (E-, TW- and GM-distributions) have been considered. It was found that the maximal life span depends on the threshold concentration of vital receptors. Equations are obtained for the dependence of the maximal life span on the kinetic parameters in the reactions of inactivation, destruction and inactivation. Dependence of maximal time life on initial size of the population have been considered. The influence of temperature on the survival curves is analysed by E-distribution. Equations are founded for the description of thermosurvival and thermoinactivation curves. Equation are obtained for the dependence of density function and it characteristics (modal and antimodal age, coefficient of asymmetry) on the MVR parameters. It was shown that E-, TW- and GM-distribution has different types of asymmetry. The coefficient of asymmetry of GM-distribution is associated on the MVR parameters. It is assumed that symmetry of the curves of mortality and birth-rate is coordinated by the mechanisms of MVR.
The Survival of the Sagittarius Dwarf Galaxy and the Flatness of the Rotation Curve of the Galaxy
Zhao, HongSheng
1998-06-01
How has the ``fluffy'' Sgr dwarf galaxy survived its 10-20 pericentric passages in the halo of the Milky Way for a Hubble time? The scenario that Sgr was deflected to its current orbit by the Magellanic Clouds after a rendezvous on the north Galactic pole 2-3 Gyr ago is examined. It is shown that the conditions of the collision fix both the sense of circulation of Sgr and the Large Magellanic Cloud around the Galaxy and the slope of the Galactic rotation curve. The model argues that the two orthogonal polar circles traced by a dozen or so Galactic halo dwarf galaxies and globular clusters (LMC-SMC-Magellanic Stream-Draco-Ursa Minor along l~270deg and M54-Ter 7-Ter 8-Arp 2-NGC 2419-Pal 15 along l~0deg) are streams of tidal relics from two ancient galaxies that were captured on two intersecting polar rosette orbits by the Galaxy. Our results favor the interpretation of microlensing toward the LMC being due to source or lens stars in tidal features of the Magellanic Clouds. We discuss direct and indirect observations to test the collision scenario.
Directory of Open Access Journals (Sweden)
Jakub Jurasz
2016-01-01
Full Text Available Polish energy sector is (almost from its origin dominated by fossil fuel feed power. This situation results from an abundance of relatively cheap coal (hard and lignite. Brown coal due to its nature is the cheapest energy source in Poland. However, hard coal which fuels 60% of polish power plants is picking up on prices and is susceptible to the coal imported from neighboring countries. Forced by the European Union (EU regulations, Poland is struggling at achieving its goal of reaching 15% of energy consumption from renewable energy sources (RES by 2020. Over the year 2015, RES covered 11.3% of gross energy consumption but this generation was dominated by solid biomass (over 80%. The aim of this paper was to answer the following research questions: What is the relation of irradiation values to the power load on a yearly and daily basis? and how should photovoltaics (PV be integrated in the polish power system? Conducted analysis allowed us to state that there exists a negative correlation between power demand and irradiation values on a yearly basis, but this is likely to change in the future. Secondly, on average, daily values of irradiation tend to follow power load curve over the first hours of the day.
A gymkhana to discover and generate curves in a cooperative work
Directory of Open Access Journals (Sweden)
Anna Vidal Meló
2014-03-01
Full Text Available The student who access the University understands a curve as a function represented by an equality involving the Cartesian variables x and y. But he does not know another great set of curves such as those described by parametric equations and polar coordinates. We show an experience developed in two consecutive courses in the first course of a bachelor's degree, which allows the students to discover and create many curves in parametric or polar representation, working in group. Also the experience facilitate the students to achieve several generic skills.
Kawano, Shingo; Komai, Yoshinobu; Ishioka, Junichiro; Sakai, Yasuyuki; Fuse, Nozomu; Ito, Masaaki; Kihara, Kazunori; Saito, Norio
2016-10-01
The aim of this study was to determine risk factors for survival after retrograde placement of ureteral stents and develop a prognostic model for advanced gastrointestinal tract (GIT: esophagus, stomach, colon and rectum) cancer patients. We examined the clinical records of 122 patients who underwent retrograde placement of a ureteral stent against malignant extrinsic ureteral obstruction. A prediction model for survival after stenting was developed. We compared its clinical usefulness with our previous model based on the results from nephrostomy cases by decision curve analysis. Median follow-up period was 201 days (8-1490) and 97 deaths occurred. The 1-year survival rate in this cohort was 29%. Based on multivariate analysis, primary site of colon origin, absence of retroperitoneal lymph node metastasis and serum albumin >3g/dL were significantly associated with a prolonged survival time. To develop a prognostic model, we divided the patients into 3 risk groups of favorable: 0-1 factors (N.=53), intermediate: 2 risk factors (N.=54), and poor: 3 risk factors (N.=15). There were significant differences in the survival profiles of these 3 risk groups (P<0.0001). Decision curve analyses revealed that the current model has a superior net benefit than our previous model for most of the examined probabilities. We have developed a novel prognostic model for GIT cancer patients who were treated with retrograde placement of a ureteral stent. The current model should help urologists and medical oncologists to predict survival in cases of malignant extrinsic ureteral obstruction.
Wennberg, Berit M; Baumann, Pia; Gagliardi, Giovanna; Nyman, Jan; Drugge, Ninni; Hoyer, Morten; Traberg, Anders; Nilsson, Kristina; Morhed, Elisabeth; Ekberg, Lars; Wittgren, Lena; Lund, Jo-Åsmund; Levin, Nina; Sederholm, Christer; Lewensohn, Rolf; Lax, Ingmar
2011-05-01
In SBRT of lung tumours no established relationship between dose-volume parameters and the incidence of lung toxicity is found. The aim of this study is to compare the LQ model and the universal survival curve (USC) to calculate biologically equivalent doses in SBRT to see if this will improve knowledge on this relationship. Toxicity data on radiation pneumonitis grade 2 or more (RP2+) from 57 patients were used, 10.5% were diagnosed with RP2+. The lung DVHs were corrected for fractionation (LQ and USC) and analysed with the Lyman- Kutcher-Burman (LKB) model. In the LQ-correction α/β = 3 Gy was used and the USC parameters used were: α/β = 3 Gy, D(0) = 1.0 Gy, [Formula: see text] = 10, α = 0.206 Gy(-1) and d(T) = 5.8 Gy. In order to understand the relative contribution of different dose levels to the calculated NTCP the concept of fractional NTCP was used. This might give an insight to the questions of whether "high doses to small volumes" or "low doses to large volumes" are most important for lung toxicity. NTCP analysis with the LKB-model using parameters m = 0.4, D(50) = 30 Gy resulted for the volume dependence parameter (n) with LQ correction n = 0.87 and with USC correction n = 0.71. Using parameters m = 0.3, D(50) = 20 Gy n = 0.93 with LQ correction and n = 0.83 with USC correction. In SBRT of lung tumours, NTCP modelling of lung toxicity comparing models (LQ,USC) for fractionation correction, shows that low dose contribute less and high dose more to the NTCP when using the USC-model. Comparing NTCP modelling of SBRT data and data from breast cancer, lung cancer and whole lung irradiation implies that the response of the lung is treatment specific. More data are however needed in order to have a more reliable modelling.
Czech Academy of Sciences Publication Activity Database
Quan Luna, B.; Blahůt, Jan; van Westen, C.J.; Sterlacchini, S.; van Asch, T.W.J.; Akbas, S.O.
2011-01-01
Roč. 11, č. 7 (2011), s. 2047-2060 ISSN 1561-8633 Institutional research plan: CEZ:AV0Z30460519 Keywords : debris flow modelling * hazard * vulnerability curves Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.983, year: 2011 http://www.nat-hazards-earth-syst-sci.net/11/2047/2011/
Achieving congruency of phylogenetic trees generated by W-curves of genomic sequences.
Cork, Douglas J; Hutch, Thomas B; Marland, Elizabeth; Zmuda, Jory
2002-12-01
Comparative genomic analysis at its most fundamental level involves alignment and analysis of linear strings of DNA. Many useful and powerful tools, such as BlastN and ClustalW are able to respectively, search for, and align similar strings of DNA from a variety of species. However, interesting genomic patterns cannot be immediately visualized within the information contact embedded in long genomic strings without extensive a priori knowledge. More problematic is the question of whether we will be able to crystallize long genomic sequences and analyze their true secondary and tertiary structures. It is, of course, these putative motifs that are binding to the three-dimensional structures of proteins and inducing replication and transcription events. The W-curve is a numerical mapping algorithm that allows one to geometrically visualize the information content of genomic motifs. Patterns of ALU, LINES, SINEs, and duplication sequences may be easily visualized with the W-curve. It is our hope that this pattern recognition algorithm will lead to visualization tools to track the evolutionary history of motif patterns. The combinatorics of DNA motif crossover-recombination events will be more easily followed as we continue to sequence more and more genomes. In our laboratory we are currently collaborating with mathematicians and computer scientists to develop and test tools, such as the W-curve, for analyzing patterns of long genomic sequences. In this paper, we examine the limitations of using the W-curve to infer the phylogenetic history of species.
Feasible Path Generation Using Bezier Curves for Car-Like Vehicle
Latip, Nor Badariyah Abdul; Omar, Rosli
2017-08-01
When planning a collision-free path for an autonomous vehicle, the main criteria that have to be considered are the shortest distance, lower computation time and completeness, i.e. a path can be found if one exists. Besides that, a feasible path for the autonomous vehicle is also crucial to guarantee that the vehicle can reach the target destination considering its kinematic constraints such as non-holonomic and minimum turning radius. In order to address these constraints, Bezier curves is applied. In this paper, Bezier curves are modeled and simulated using Matlab software and the feasibility of the resulting path is analyzed. Bezier curve is derived from a piece-wise linear pre-planned path. It is found that the Bezier curves has the capability of making the planned path feasible and could be embedded in a path planning algorithm for an autonomous vehicle with kinematic constraints. It is concluded that the length of segments of the pre-planned path have to be greater than a nominal value, derived from the vehicle wheelbase, maximum steering angle and maximum speed to ensure the path for the autonomous car is feasible.
Generation of a Sediment Rating and Load Curve Demonstrated at the Mackinaw River Confluence
2016-12-01
CHETN) contains a description of the process to formulate sediment rating and load curves for the bed material load in the Mackinaw River. The...River watershed (Adjusted). NORMAL DEPTH COMPUTATION: Normal depth computations were computed with the Stable Analytical Method (SAM) Hydraulic Design
Influence of design and mode parameters on pump performance curve of heat generating aggregate
Barykin, O.; Kovalyov, S.; Ovcharenko, M.; Papchenko, A.
2017-08-01
Classification of multi-functional heat generating aggregates according to the function is considered in this article. Analysis of operating process mathematical model was implemented and methods for its refinement were proposed. Results of physical investigation of heat generating aggregate design and mode parameters influence on its power and head were presented.
Directory of Open Access Journals (Sweden)
Buha Danilo
2016-01-01
Full Text Available The relay protection settings performed in the largest thermal powerplant (TE "Nikola Tesla B" are reffered and explained in this paper. The first calculation step is related to the coordination of the maximum stator current limiter settings, the overcurrent protection with inverse characteristics settings and the permitted overload of the generator stator B1. In the second calculation step the settings of impedance generator protection are determined, and the methods and criteria according to which the calculations are done are described. Criteria used to provide the protection to fulfill the backup protection role in the event of malfunction of the main protection of the transmission system. are clarified. The calculation of all protection functions (32 functions of generator B1 were performed in the project "Coordination of relay protection blocks B1 and B2 with the system of excitation and power system protections -TENT B".
Luna, B. Quan; Blahut, J.; van Westen, C. J.; Sterlacchini, S.; van Asch, T. W. J.; Akbas, S. O.
2011-07-01
For a quantitative assessment of debris flow risk, it is essential to consider not only the hazardous process itself but also to perform an analysis of its consequences. This should include the estimation of the expected monetary losses as the product of the hazard with a given magnitude and the vulnerability of the elements exposed. A quantifiable integrated approach of both hazard and vulnerability is becoming a required practice in risk reduction management. This study aims at developing physical vulnerability curves for debris flows through the use of a dynamic run-out model. Dynamic run-out models for debris flows are able to calculate physical outputs (extension, depths, velocities, impact pressures) and to determine the zones where the elements at risk could suffer an impact. These results can then be applied to consequence analyses and risk calculations. On 13 July 2008, after more than two days of intense rainfall, several debris and mud flows were released in the central part of the Valtellina Valley (Lombardy Region, Northern Italy). One of the largest debris flows events occurred in a village called Selvetta. The debris flow event was reconstructed after extensive field work and interviews with local inhabitants and civil protection teams. The Selvetta event was modelled with the FLO-2D program, an Eulerian formulation with a finite differences numerical scheme that requires the specification of an input hydrograph. The internal stresses are isotropic and the basal shear stresses are calculated using a quadratic model. The behaviour and run-out of the flow was reconstructed. The significance of calculated values of the flow depth, velocity, and pressure were investigated in terms of the resulting damage to the affected buildings. The physical damage was quantified for each affected structure within the context of physical vulnerability, which was calculated as the ratio between the monetary loss and the reconstruction value. Three different empirical
U.S. Geological Survey, Department of the Interior — These data provide information on the survival of California red-legged frogs in a unique ecosystem to better conserve this threatened species while restoring...
Wind Turbine Power Curve Design for Optimal Power Generation in Wind Farms Considering Wake Effect
DEFF Research Database (Denmark)
Tian, Jie; Zhou, Dao; Su, Chi
2017-01-01
In modern wind farms, maximum power point tracking (MPPT) is widely implemented. Using the MPPT method, each individual wind turbine is controlled by its pitch angle and tip speed ratio to generate the maximum active power. In a wind farm, the upstream wind turbine may cause power loss to its...... downstream wind turbines due to the wake effect. According to the wake model, downstream power loss is also determined by the pitch angle and tip speed ratio of the upstream wind turbine. By optimizing the pitch angle and tip speed ratio of each wind turbine, the total active power of the wind farm can...... be increased. In this paper, the optimal pitch angle and tip speed ratio are selected for each wind turbine by the exhausted search. Considering the estimation error of the wake model, a solution to implement the optimized pitch angle and tip speed ratio is proposed, which is to generate the optimal control...
DEFF Research Database (Denmark)
Timar-Gabor, Alida; Constantin, Daniela; Buylaert, Jan-Pieter
2015-01-01
saturation much earlier. Analysis of time resolved spectra indicated similar luminescence lifetimes for both fine and coarse quartz grains, and natural and laboratory generated OSL signals seem to use the same non-dosedependent recombination pathways. The natural signals of a sample with an expected......SAR-OSL investigations on quartz from Romanian loess resulted in non concordant fine and coarse-grain ages for equivalent doses higher than ~100 Gy. The laboratory dose response for both grain sizes is well represented by a sum of two saturating exponential functions, fine and coarse grains...... equivalent dose of 2000e2500 Gy were found to be below the saturation level of the laboratory dose response curve for both grain sizes; this also applied to the luminescence signals measured after >5000 Gy given on top of natural doses. © 2015 Elsevier Ltd. All rights reserved....
Yoganandan, Narayan; Arun, Mike W J; Pintar, Frank A; Banerjee, Anjishnu
2015-01-01
Derive lower leg injury risk functions using survival analysis and determine injury reference values (IRV) applicable to human mid-size male and small-size female anthropometries by conducting a meta-analysis of experimental data from different studies under axial impact loading to the foot-ankle-leg complex. Specimen-specific dynamic peak force, age, total body mass, and injury data were obtained from tests conducted by applying the external load to the dorsal surface of the foot of postmortem human subject (PMHS) foot-ankle-leg preparations. Calcaneus and/or tibia injuries, alone or in combination and with/without involvement of adjacent articular complexes, were included in the injury group. Injury and noninjury tests were included. Maximum axial loads recorded by a load cell attached to the proximal end of the preparation were used. Data were analyzed by treating force as the primary variable. Age was considered as the covariate. Data were censored based on the number of tests conducted on each specimen and whether it remained intact or sustained injury; that is, right, left, and interval censoring. The best fits from different distributions were based on the Akaike information criterion; mean and plus and minus 95% confidence intervals were obtained; and normalized confidence interval sizes (quality indices) were determined at 5, 10, 25, and 50% risk levels. The normalization was based on the mean curve. Using human-equivalent age as 45 years, data were normalized and risk curves were developed for the 50th and 5th percentile human size of the dummies. Out of the available 114 tests (76 fracture and 38 no injury) from 5 groups of experiments, survival analysis was carried out using 3 groups consisting of 62 tests (35 fracture and 27 no injury). Peak forces associated with 4 specific risk levels at 25, 45, and 65 years of age are given along with probability curves (mean and plus and minus 95% confidence intervals) for PMHS and normalized data applicable to
Liu, Song; Jin, Hua; Song, KeWei; Wang, LiangChen; Wu, Xiang; Wang, LiangBi
2017-10-01
The heat transfer performance of the tube bank fin heat exchanger is limited by the air-side thermal resistance. Thus, enhancing the air-side heat transfer is an effective method to improve the performance of the heat exchanger. A new fin pattern with flow redistributors and curved triangular vortex generators is experimentally studied in this paper. The effects of the flow redistributors located in front of the tube stagnation point and the curved vortex generators located around the tube on the characteristics of heat transfer and pressure drop are discussed in detail. A performance comparison is also carried out between the fins with and without flow redistributors. The experimental results show that the flow redistributors stamped out from the fin in front of the tube stagnation points can decrease the friction factor at the cost of decreasing the heat transfer performance. Whether the combination of the flow redistributors and the curved vortex generators will present a better heat transfer performance depends on the size of the curved vortex generators. As for the studied two sizes of vortex generators, the heat transfer performance is promoted by the flow redistributors for the fin with larger size of vortex generators and the performance is suppressed by the flow redistributors for the fin with smaller vortex generators.
Carvalho, Celina Soares; Souza, Daiane Spitz; Lopes, Jessica Rodrigues; Castanho, Ivany Alves; Lopes, Agnaldo José
2017-08-01
A significant number of cancer deaths is partly due to late diagnosis of the disease at an advanced stage beyond cure. In this context, by applying the adequate tools, palliative care provides terminal cancer patients with the proper support for survival with a higher quality of life. The objective of this study was to describe the nutritional profile of terminal cancer patients and to evaluate the relationship among Patient-Generated Subjective Global Assessment (PG-SGA) score, clinical-functional characteristics and survival. The present work is a retrospective cohort study with 104 terminal cancer patients. The Karnofsky Performance Status (KPS) was used to obtain socio-demographic data and clinical history and assess functional capacity. Furthermore, patients were classified by groups and PG-SGA score ranges. In the first medical consultation, the PG-SGA revealed that most patients were moderately or severely malnourished and in critical need of immediate symptom management. Functional capacity of almost half of all patients lay within a KPS score of 40 to 70. Survival analysis revealed that the median time of mortality by cancer was 5 (3.3-6.7) months. Furthermore, patients with an SGA-C, i.e., severely malnourished (Ppatients. The use of this tool in the studied population is of paramount importance to provide individualised and adequate support for these patients.
Bergant, Marcos A.; Yawny, Alejandro A.; Perez Ipiña, Juan E.
2017-04-01
The structural integrity of steam generator tubes is a relevant issue concerning nuclear plant safety. In the present work, J-resistance curves of Inconel 690 and Incoloy 800 nuclear steam generator tubes with circumferential and longitudinal through wall cracks were obtained at room temperature and 300 °C using recently developed non-standard specimens' geometries. It was found that Incoloy 800 tubes exhibited higher J-resistance curves than Inconel 690 for both crack orientations. For both materials, circumferential cracks resulted into higher fracture resistance than longitudinal cracks, indicating a certain degree of texture anisotropy introduced by the tube fabrication process. From a practical point of view, temperature effects have found to be negligible in all cases. The results obtained in the present work provide a general framework for further application to structural integrity assessments of cracked tubes in a variety of nuclear steam generator designs.
Directory of Open Access Journals (Sweden)
E. Durán
2012-01-01
Full Text Available A versatile measurement system for systematic testing and measurement of the evolution of the I-V characteristic curves of photovoltaic panels or arrays (PV generators is proposed in this paper. The measurement system uses a circuit solution based on DC-DC converters that involves several advantages relative to traditional methods: simple structure, scalability, fast response, and low cost. The measurement of the desired characteristics of PV generators includes high speed of response and high fidelity. The prototype system built is governed by a microcontroller, and experimental results prove the proposed measurement system useful. A virtual instrument (VI was developed for full system control from a computer. The developed system enables monitoring the suitable operation of a PV generator in real time, since it allows comparing its actual curves with those provided by the manufacturer.
Peskine, Christian; Sernesi, Edoardo
1987-01-01
The main topics of the conference on "Curves in Projective Space" were good and bad families of projective curves, postulation of projective space curves and classical problems in enumerative geometry.
Energy Technology Data Exchange (ETDEWEB)
Fynan, Douglas A.; Ahn, Kwang-Il, E-mail: kiahn@kaeri.re.kr
2016-12-15
Highlights: • Pressure drop-flow rate curves for superheated steam in U-tubes were generated. • Forward flow of hot steam is favored in the longer and taller U-tubes. • Reverse flow of cold steam is favored in short U-tubes. • Steam generator U-tube bundle geometry and tube diameter are important. • Need for correlation development for natural convention heat transfer coefficient. - Abstract: Characteristic pressure drop-flow rate curves are generated for all row numbers of the OPR1000 steam generators (SGs), representative of Combustion Engineering (CE) type SGs featuring square bend U-tubes. The pressure drop-flow rate curves are applicable to severe accident natural circulations of single-phase superheated steam during high pressure station blackout sequences with failed auxiliary feedwater and dry secondary side which are closely related to the thermally induced steam generator tube rupture event. The pressure drop-flow rate curves which determine the recirculation rate through the SG tubes are dependent on the tube bundle geometry and hydraulic diameter of the tubes. The larger CE type SGs have greater variation of tube length and height as a function of row number with forward flow of steam favored in the longer and taller high row number tubes and reverse flow favored in the short low row number tubes. Friction loss, natural convection heat transfer coefficients, and temperature differentials from the primary to secondary side are dominant parameters affecting the recirculation rate. The need for correlation development for natural convection heat transfer coefficients for external flow over tube bundles currently not modeled in system codes is discussed.
Directory of Open Access Journals (Sweden)
Schäffer Alejandro A
2008-11-01
Full Text Available Abstract Background Fluorescence of dyes bound to double-stranded PCR products has been utilized extensively in various real-time quantitative PCR applications, including post-amplification dissociation curve analysis, or differentiation of amplicon length or sequence composition. Despite the current era of whole-genome sequencing, mapping tools such as radiation hybrid DNA panels remain useful aids for sequence assembly, focused resequencing efforts, and for building physical maps of species that have not yet been sequenced. For placement of specific, individual genes or markers on a map, low-throughput methods remain commonplace. Typically, PCR amplification of DNA from each panel cell line is followed by gel electrophoresis and scoring of each clone for the presence or absence of PCR product. To improve sensitivity and efficiency of radiation hybrid panel analysis in comparison to gel-based methods, we adapted fluorescence-based real-time PCR and dissociation curve analysis for use as a novel scoring method. Results As proof of principle for this dissociation curve method, we generated new maps of river buffalo (Bubalus bubalis chromosome 20 by both dissociation curve analysis and conventional marker scoring. We also obtained sequence data to augment dissociation curve results. Few genes have been previously mapped to buffalo chromosome 20, and sequence detail is limited, so 65 markers were screened from the orthologous chromosome of domestic cattle. Thirty bovine markers (46% were suitable as cross-species markers for dissociation curve analysis in the buffalo radiation hybrid panel under a standard protocol, compared to 25 markers suitable for conventional typing. Computational analysis placed 27 markers on a chromosome map generated by the new method, while the gel-based approach produced only 20 mapped markers. Among 19 markers common to both maps, the marker order on the map was maintained perfectly. Conclusion Dissociation curve
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.
D'Ancona, G; Agma, H. U.; Kische, S.; El-Achkar, G.; Di?mann, M.; Ortak, J.; Ince, H.; U. Ketterer; B?risch, A.; ?ner, A.
2016-01-01
Objectives We present our single-centre experience with the direct flow medical (DFM) trans-catheter aortic valve implantation (TAVI) prosthesis addressing the impact of learning curve upon outcomes. Background The DFM has been recently introduced for TAVI. The prosthesis presents original design and implantation features. Methods Patients were divided into three groups according to the chronological implantation sequence that reflected technical skills acquisition of the entire team. Results...
Energy Technology Data Exchange (ETDEWEB)
Santos, Adriano M.; Meira-Belo, Luiz C.; Reis, Sergio C.; Grynberg, Suely E., E-mail: amsantos@cdtn.b [Center for Development of Nuclear Technology (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)
2011-07-01
The interstitial brachytherapy is one modality of radiotherapy in which radioactive sources are placed directly in the region to be treated or close to it. The seeds that are used in the treatment of prostate cancer are generally cylindrical radioactive sources, consisting of a ceramic or metal matrix, which acts as the carrier of the radionuclide and as the X-ray marker, encapsulated in a sealed titanium tube. This study aimed to develop a computational model to reproduce the film-seed geometry, in order to obtain the spatial regions of the isodose curves produced by the seed when it is put over the film surface. The seed modeled in this work was the OncoSeed 6711, a sealed source of iodine-125, which its isodose curves were obtained experimentally in previous work with the use of dosimetric films. For the films modeling, compositions and densities of the two types of dosimetric films were used: Agfa Personal Monitoring photographic film 2/10, manufactured by Agfa-Geavaert; and the model EBT radiochromic film, by International Specialty Products. The film-seed models were coupled to the Monte Carlo code MCNP5. The results obtained by simulations showed to be in good agreement with experimental results performed in a previous work. This indicates that the computational model can be used in future studies for other seeds models. (author)
Ryder, Thomas B; Reitsma, Robert; Evans, Brian; Marra, Peter P
2010-03-01
Despite the increasing pace of urbanization little is known about the factors that limit bird populations (i.e., population-level processes) within the urban/suburban land-use matrix. Here, we report rates of nest survival within the matrix of an urban land-use gradient in the greater Washington, D.C., USA, area for five common songbirds using data collected by scientists and citizens as part of a project called Neighborhood Nestwatch. Using program MARK, we modeled the effects of species, urbanization at multiple spatial scales (canopy cover and impervious surface), and observer (citizen vs. scientist) on nest survival of four open-cup and one cavity-nesting species. In addition, artificial nests were used to determine the relative impacts of specific predators along the land-use gradient. Our results suggest that predation on nests within the land-use matrix declines with urbanization but that there are species-specific differences. Moreover, variation in nest survival among species was best explained by urbanization metrics measured at larger "neighborhood" spatial scales (e.g., 1000 m). Trends were supported by data from artificial nests and suggest that variable predator communities (avian vs. mammalian) are one possible mechanism to explain differential nest survival. In addition, we assessed the quality of citizen science data and show that citizens had no negative effect on nest survival and provided estimates of nest survival comparable to Smithsonian biologists. Although birds nesting within the urban matrix experienced higher nest survival, individuals also faced a multitude of other challenges such as contaminants and invasive species, all of which could reduce adult survival.
D'Ancona, G; Agma, H U; Kische, S; El-Achkar, G; Dißmann, M; Ortak, J; Ince, H; Ketterer, U; Bärisch, A; Öner, A
2017-02-01
We present our single-centre experience with the direct flow medical (DFM) trans-catheter aortic valve implantation (TAVI) prosthesis addressing the impact of learning curve upon outcomes. The DFM has been recently introduced for TAVI. The prosthesis presents original design and implantation features. Patients were divided into three groups according to the chronological implantation sequence that reflected technical skills acquisition of the entire team. Group I included the first 20 patients (early learning phase), group II the second 20 patients (proctoring to other members of the team), and group III the following 93 patients (technique consolidation). Differences in baseline and procedural variables were analysed. Nonparametric correlation and linear regression were used to identify changes according to institutional cumulative experience. There was a significant correlation between catheterisation time and institutional experience (rho = -0.4; p proctoring and technical consolidation phase.
Wood, Daniel N; Weinstein, Kathryn E; Podbielski, Andreas; Kreikemeyer, Berndt; Gaughan, John P; Valentine, Samara; Buttaro, Bettina A
2009-10-01
Streptococcus pyogenes, in addition to causing fulminant disease, can be carried asymptomatically and may survive in the host without causing disease. Long-term stationary-phase cultures were used to characterize the metabolism of cultures surviving after glucose depletion. Survival of stationary-phase cultures in glucose-depleted rich medium was truncated by switching the cells to phosphate-buffered saline or by the addition of antibiotics, suggesting that survival depended on the presence of nutrients and metabolic activity. The metabolites of the pyruvate-to-acetate (PA) pathway (acetate and formate) and amino acid catabolic pathways (ammonia) accumulated throughout long-term stationary phase (12 weeks). Acid and ammonia production was balanced so that the culture pH was maintained above pH 5.6. Strains isolated from long-term stationary-phase cultures accumulated mutations that resulted in unique exponential-phase metabolisms, with some strains expressing the PA pathway, some strains producing ammonia, and some strains expressing both in the presence of glucose. Strains expressing high levels of PA pathway activity during exponential growth were unable to survive when regrown in pure culture due to the production of excess acid. These data suggest that S. pyogenes diversifies during survival in stationary phase into distinct strains with different metabolisms and that complementary metabolism is required to control the pH in stationary-phase cultures. One of three survivor strains isolated from tonsillar discard material from patients expressed high levels of the PA pathway during exponential growth. Sequencing of multiple group A streptococcus regulators revealed two different mutations in two different strains, suggesting that random mutation occurs during survival.
Meihls, Lisa N; Higdon, Matthew L; Siegfried, Blair D; Miller, Nicholas J; Sappington, Thomas W; Ellersieck, Mark R; Spencer, Terence A; Hibbard, Bruce E
2008-12-09
To delay evolution of insect resistance to transgenic crops producing Bacillus thuringiensis (Bt) toxins, nearby "refuges" of host plants not producing Bt toxins are required in many regions. Such refuges are expected to be most effective in slowing resistance when the toxin concentration in Bt crops is high enough to kill all or nearly all insects heterozygous for resistance. However, Bt corn, Zea mays, introduced recently does not meet this "high-dose" criterion for control of western corn rootworm (WCR), Diabrotica virgifera virgifera. A greenhouse method of rearing WCR on transgenic corn expressing the Cry3Bb1 protein was used in which approximately 25% of previously unexposed larvae survived relative to isoline survival (compared to 1-4% in the field). After three generations of full larval rearing on Bt corn (Constant-exposure colony), WCR larval survival was equivalent on Bt corn and isoline corn in greenhouse trials, and the LC(50) was 22-fold greater for the Constant-exposure colony than for the Control colony in diet bioassays with Cry3Bb1 protein on artificial diet. After six generations of greenhouse selection, the ratio of larval recovery on Bt corn to isoline corn in the field was 11.7-fold greater for the Constant-exposure colony than the Control colony. Removal from selection for six generations did not decrease survival on Bt corn in the greenhouse. The results suggest that rapid response to selection is possible in the absence of mating with unexposed beetles, emphasizing the importance of effective refuges for resistance management.
Schwarz, Albert
2014-01-01
One says that a pair (P,Q) of ordinary differential operators specify a quantum curve if [P,Q]=const. If a pair of difference operators (K,L) obey the relation KL=const LK we say that they specify a discrete quantum curve. This terminology is prompted by well known results about commuting differential and difference operators, relating pairs of such operators with pairs of meromorphic functions on algebraic curves obeying some conditions. ...
Uchiyama, M; Jin, X; Zhang, Q; Amano, A; Watanabe, T; Niimi, M
2012-05-01
In clinical practice, music has been used to decrease stress, heart rate, and blood pressure and to provide a distraction from disease symptoms. We investigated sound effects on alloimmune responses in murine heart transplantation. Naïve and eardrum-ruptured CBA/N (CBA, H2(K)) underwent transplantation of a C57BL/6 (B6, H2(b)) heart and were exposed to 1 of 3 types of music-opera (La Traviata), classical (Mozart), and New Age (Enya)-or 1 of 6 different single sound frequencies for 7 days. An adoptive transfer study was performed to determine whether regulatory cells were generated in allograft recipients. Cell-proliferation, cytokine, and flow cytometry assessments were also performed. CBA recipients of a B6 graft exposed to opera and classical music had significantly prolonged allograft survival (median survival times [MSTs], 26.5 and 20 days, respectively), whereas those exposed to 6 single sound frequencies and New Age did not (MSTs, 7, 8, 9, 8, 8, 8, and 11 days, respectively). Untreated and eardrum-ruptured CBA rejected B6 grafts acutely (MSTs, 7 and 8.5 days, respectively). Adoptive transfer of whole splenocytes, CD4(+) cells, and CD4(+)CD25(+) cells from opera-exposed primary recipients resulted in significantly prolonged allograft survival in naive secondary recipients (MSTs, 36, 68, and >50 days, respectively). Cell-proliferation, interleukin (IL)-2 and interferon-γ were suppressed in opera-exposed mice, whereas IL-4 and IL-10 from opera-exposed recipients were up-regulated. Flow cytometry studies showed an increased CD4(+)CD25(+)Foxp3(+) cell population in splenocytes from opera-exposed mice. In conclusion, exposure to some types of music may induce prolonged survival of fully allogeneic cardiac allografts and generate CD4(+)CD25(+)Foxp3(+) regulatory cells. Copyright © 2012 Elsevier Inc. All rights reserved.
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Paul Bourgine
2014-03-01
By combining the opposite concepts of ‘induced-life’ and ‘inducible-death’, we generated a hMSCs line with defined properties and allowing for temporally controlled survival. The cell line represents a relevant tool for medical discovery in regenerative medicine and a potential means to address availability, standardization and safety requirements in cell & gene therapy. The concept of a hTERT-iCasp9 combination, here explored in the context of hMSCs, could be extended to other types of progenitor/stem cells.
Luo, Y.; Xia, J.; Liu, J.; Xu, Y.; Liu, Q.
2008-01-01
Multichannel Analysis of Surface Waves utilizes a multichannel recording system to estimate near-surface shear (S)-wave velocities from high-frequency Rayleigh waves. A pseudo-2D S-wave velocity (vS) section is constructed by aligning 1D models at the midpoint of each receiver spread and using a spatial interpolation scheme. The horizontal resolution of the section is therefore most influenced by the receiver spread length and the source interval. The receiver spread length sets the theoretical lower limit and any vS structure with its lateral dimension smaller than this length will not be properly resolved in the final vS section. A source interval smaller than the spread length will not improve the horizontal resolution because spatial smearing has already been introduced by the receiver spread. In this paper, we first analyze the horizontal resolution of a pair of synthetic traces. Resolution analysis shows that (1) a pair of traces with a smaller receiver spacing achieves higher horizontal resolution of inverted S-wave velocities but results in a larger relative error; (2) the relative error of the phase velocity at a high frequency is smaller than at a low frequency; and (3) a relative error of the inverted S-wave velocity is affected by the signal-to-noise ratio of data. These results provide us with a guideline to balance the trade-off between receiver spacing (horizontal resolution) and accuracy of the inverted S-wave velocity. We then present a scheme to generate a pseudo-2D S-wave velocity section with high horizontal resolution using multichannel records by inverting high-frequency surface-wave dispersion curves calculated through cross-correlation combined with a phase-shift scanning method. This method chooses only a pair of consecutive traces within a shot gather to calculate a dispersion curve. We finally invert surface-wave dispersion curves of synthetic and real-world data. Inversion results of both synthetic and real-world data demonstrate that
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Olesen, Mikkel Vestergaard; Wörtwein, Gitta; Folke, Jonas
2017-01-01
of the previous work aiming to test the hypothesis that rats subjected to ECS in combination with chronic restraint stress (CRS) display increased formation of new hippocampal neurons, which have a potential for long-term survival. Furthermore, using mediation analysis, we tested if an ECS-induced increase......U-positive neurons showed time-dependent attrition of ∼40% from day 1 to 3 months, with no further decline between 3 and 12 months. ECS did not affect the number of pre-existing dentate granule neurons or the volume of the dentate granule cell layer, suggesting no damaging effect of the treatment. Finally, we found...... that, while ECS increases neurogenesis, this formation of new neurons was not associated to ameliorated immobility in the FST. This implies that other ECS-induced effects than neurogenesis must be part of mediating the antidepressant action of ECS. Taken together, the results of the present study...
Survival of non-Western first generations immigrants with stomach cancer in North East Netherlands
Siemerink, E.J.M.; van der Aa, M.A.; Siesling, Sabine; Hospers, G.A.P.; Mulder, N.H.
2011-01-01
Background: Isolated groups, such as first generation non-Western immigrants, are at risk for suboptimal utilisation of the health care system resulting in a worse outcome. Methods: From 1989 to 2007, all patients with stomach cancer were selected from the Comprehensive Cancer Centre North-East
White, Laura M.; Lau, Katherine S. L.; Perkins, Anthony; Monahan, Patrick; Grisso, Thomas
2015-01-01
Objectives. We examined the provision of behavioral health services to youths detained in Indiana between 2008 and 2012 and the impact of services on recidivism. Method. We obtained information about behavioral health needs, behavioral health treatment received, and recidivism within 12 months after release for 8363 adolescents (aged 12–18 years; 79.4% male). We conducted survival analyses to determine whether behavioral health services significantly affected time to recidivating. Results. Approximately 19.1% of youths had positive mental health screens, and 25.3% of all youths recidivated within 12 months after release. Of youths with positive screens, 29.2% saw a mental health clinician, 16.1% received behavioral health services during detention, and 30.0% received referrals for postdetention services. Survival analyses showed that being male, Black, and younger, and having higher scores on the substance use or irritability subscales of the screen predicted shorter time to recidivism. Receiving a behavior precaution, behavioral health services in detention, or an assessment in the community also predicted shorter time to recidivating. Conclusions. Findings support previous research showing that behavioral health problems are related to recidivism and that Black males are disproportionately rearrested after detention. PMID:25973804
Cafri, Guy; Banerjee, Samprit; Sedrakyan, Art; Paxton, Liz; Furnes, Ove; Graves, Stephen; Marinac-Dabic, Danica
2015-12-01
The motivating example for this paper comes from a distributed health data network, the International Consortium of Orthopaedic Registries (ICOR), which aims to examine risk factors for orthopedic device failure for registries around the world. Unfortunately, regulatory, privacy, and propriety concerns made sharing of raw data impossible, even if de-identified. Therefore, this article describes an approach to extraction and analysis of aggregate time-to-event data from ICOR. Data extraction is based on obtaining a survival probability and variance estimate for each unique combination of the explanatory variables at each distinct event time for each registry. The extraction procedure allows for a great deal of flexibility; models can be specified after the data have been collected, for example, modeling of interaction effects and selection of subgroups of patients based on their values on the explanatory variables. Our analysis models are adapted from models presented elsewhere--but allowing for censoring in the calculation of the correlation between serial survival probabilities and using the square root of the covariance matrix to transform the data to avoid computational problems in model estimation. Simulations and a real-data example are provided with strengths and limitations of the approach discussed. Copyright © 2015 John Wiley & Sons, Ltd.
Generating political priority for newborn survival in three low-income countries.
Smith, Stephanie L; Shiffman, Jeremy; Kazembe, Abigail
2014-01-01
Deaths to babies in their first 28 days of life now account for more than 40% of global under-5 child mortality. High neonatal mortality poses a significant barrier to achieving the child survival Millennium Development Goal. Surmounting the problem requires national-level political commitment, yet only a few nation-states have prioritised this issue. We compare Bolivia, Malawi and Nepal, three low-income countries with high neonatal mortality, with a view to understanding why countries prioritise or neglect the issue. The three have had markedly different trajectories since 2000: attention grew steadily in Nepal, stagnated then grew in Malawi and grew then stagnated in Bolivia. The comparison suggests three implications for proponents seeking to advance attention to neglected health issues in low-income countries: the value of (1) advancing solutions with demonstrated efficacy in low-resource settings, (2) building on existing and emerging national priorities and (3) developing a strong network of domestic and international allies. Such actions help policy communities to weather political storms and take advantage of policy windows.
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…
Hozo, Iztok; Tsalatsanis, Athanasios; Djulbegovic, Benjamin
2016-12-15
Decision curve analysis (DCA) is a widely used method for evaluating diagnostic tests and predictive models. It was developed based on expected utility theory (EUT) and has been reformulated using expected regret theory (ERG). Under certain circumstances, these 2 formulations yield different results. Here we describe these situations and explain the variation. We compare the derivations of the EUT- and ERG-based formulations of DCA for a typical medical decision problem: "treat none," "treat all," or "use model" to guide treatment. We illustrate the differences between the 2 formulations when applied to the following clinical question: at which probability of death we should refer a terminally ill patient to hospice? Both DCA formulations yielded identical but mirrored results when treatment effects are ignored; they generated significantly different results otherwise. Treatment effect has a significant effect on the results derived by EUT DCA and less so on ERG DCA. The elicitation of specific values for disutilities affected the results even more significantly in the context of EUT DCA, whereas no such elicitation was required within the ERG framework. EUT and ERG DCA generate different results when treatment effects are taken into account. The magnitude of the difference depends on the effect of treatment and the disutilities associated with disease and treatment effects. This is important to realize as the current practice guidelines are uniformly based on EUT; the same recommendations can significantly differ if they are derived based on ERG framework. © 2016 The Authors. Journal of Evaluation in Clinical Practice Published by John Wiley & Sons Ltd.
J.J.M. Geelhoed (Miranda); H.R. Taal (Rob); R.P.M. Steegers-Theunissen (Régine); L.R. Arends (Lidia); M. Leguin (Maarten); H.A. Moll (Henriëtte); A. Hofman (Albert); A.J. van der Heijden (Bert); V.W.V. Jaddoe (Vincent)
2010-01-01
textabstractInformation about growth of kidney structures in early life is limited. In a population-based prospective cohort study, from foetal life onwards, we constructed reference curves for kidney growth from the third trimester of pregnancy until early childhood, using data from 1,158 healthy
Alemdar, N.; Leijten, Jeroen Christianus Hermanus; Camci-Unal, G.; Hjortnaes, J.; Ribas, J.; Paul, A.; Mostafalu, P.; Gaharwar, A.K.; Qiu, Y.; Sonkusale, S.; Liao, R.; Khademhosseini, A.
2016-01-01
Oxygen is essential to cell survival and tissue function. Not surprisingly, ischemia resulting from myocardial infarction induces cell death and tissue necrosis. Attempts to regenerate myocardial tissue with cell based therapies exacerbate the hypoxic stress by further increasing the metabolic
DEFF Research Database (Denmark)
von Plessen, C; Strand, T-E; Wentzel-Larsen, T
2008-01-01
BACKGROUND: To investigate whether the introduction of modern third-generation chemotherapy was associated with survival benefits in a national population of patients with advanced non-small cell lung cancer (ANSCLC) and to explore geographical and temporary variations in the utilisation...... between survival and variations in utilisation in counties were investigated. In a subgroup, the predictors of having received chemotherapy were explored. RESULTS: Of 24 875 registered patients with lung cancer, 13 757 had ANSCLC. The annual utilisation of the indicator drug in Norway increased from 3...... of chemotherapy. METHODS: All patients with ANSCLC in the Cancer Registry of Norway during 1994-2005 were included. Using sales of vinorelbine as an indicator for chemotherapy, annual county utilisation rates were calculated. Survival before and after the general introduction of vinorelbine and associations...
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Deborah D Crane
Full Text Available Francisella tularensis is a facultative intracellular bacterium and the causative agent of tularemia. Development of novel vaccines and therapeutics for tularemia has been hampered by the lack of understanding of which immune components are required to survive infection. Defining these requirements for protection against virulent F. tularensis, such as strain SchuS4, has been difficult since experimentally infected animals typically die within 5 days after exposure to as few as 10 bacteria. Such a short mean time to death typically precludes development, and therefore assessment, of immune responses directed against virulent F. tularensis. To enable identification of the components of the immune system that are required for survival of virulent F. tularensis, we developed a convalescent model of tularemia in C57Bl/6 mice using low dose antibiotic therapy in which the host immune response is ultimately responsible for clearance of the bacterium. Using this model we demonstrate αβTCR(+ cells, γδTCR(+ cells, and B cells are necessary to survive primary SchuS4 infection. Analysis of mice deficient in specific soluble mediators shows that IL-12p40 and IL-12p35 are essential for survival of SchuS4 infection. We also show that IFN-γ is required for survival of SchuS4 infection since mice lacking IFN-γR succumb to disease during the course of antibiotic therapy. Finally, we found that both CD4(+ and CD8(+ cells are the primary producers of IFN-γand that γδTCR(+ cells and NK cells make a minimal contribution toward production of this cytokine throughout infection. Together these data provide a novel model that identifies key cells and cytokines required for survival or exacerbation of infection with virulent F. tularensis and provides evidence that this model will be a useful tool for better understanding the dynamics of tularemia infection.
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CHARLES OBIERO GUMBO MBA STUDENT
2013-07-01
The study recommends that the owners/managers of the SMFEs should propose a successor for their business in good time so as to allow enough time for mentoring that could see their business survive through several generations. The study also recommends that the owners/managers should be trained on the importance of being innovative, proactive and how to take calculated risks in the business operations that would go a long way in enhancing business success.
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.
YANG, CHANG; HU, DONG-HUI; FENG, YAN
2015-01-01
The aim of the present study was to investigate the chemical composition of the essential oil of Artemisia vestita and to determine the antibacterial activity of the essential oil and its two major components, grandisol and 1,8-cineole, against certain respiratory infection-causing bacterial strains, in vitro and in vivo. The chemical composition of the essential oil was analyzed using gas chromatography-mass spectrometry. A micro-well dilution method was used to determine the minimum inhibition concentration (MIC) values of the essential oil and its major constituents. A model of Streptococcus pyogenes infection in mice was used to determine its in vivo activities. Lung and blood samples were obtained to assess bacterial cell counts. Toxicity evaluation of the essential oil and its components was completed by performing biochemical analysis of the serum, particularly monitoring aspartate transaminase, alanine transaminase, urea and creatinine. The essential oil exhibited potent antibacterial activity, whereas the two major constituents were less potent. The essential oil exhibited MIC values between 20 and 80 μg/ml, while the values of the two constituents were between 130 and 200 μg/ml. Scanning electron microscopy results demonstrated that the essential oil inhibited biofilm formation and altered its architecture. Survival curves indicated that the essential oil led to a reduction in the viability of different bacteria. The essential oil also induced significant leakage of potassium ions from S. pyogenes. The essential oil (100 μg/mouse) and grandisol (135 μg/mouse) significantly reduced the number of viable bacterial cells in the lungs (P<0.01). However, intake of 100 μg/mouse of essential oil or grandisol 135 μg/mouse once or twice each day for 9 days did not produce any toxic effects in the mice. In conclusion, the in vitro and in vivo results suggested that the essential oil of A. vestita and one of its major constituents, grandisol, can significantly
Energy Technology Data Exchange (ETDEWEB)
Kim, Y; Waldron, T; Pennington, E [University Of Iowa, College of Medicine, Iowa City, IA (United States)
2016-06-15
Purpose: To test the radiobiological impact of hypofractionated choroidal melanoma brachytherapy, we calculated single fraction equivalent doses (SFED) of the tumor that equivalent to 85 Gy of I125-BT for 20 patients. Corresponding organs-at-risks (OARs) doses were estimated. Methods: Twenty patients treated with I125-BT were retrospectively examined. The tumor SFED values were calculated from tumor BED using a conventional linear-quadratic (L-Q) model and an universal survival curve (USC). The opposite retina (α/β = 2.58), macula (2.58), optic disc (1.75), and lens (1.2) were examined. The % doses of OARs over tumor doses were assumed to be the same as for a single fraction delivery. The OAR SFED values were converted into BED and equivalent dose in 2 Gy fraction (EQD2) by using both L-Q and USC models, then compared to I125-BT. Results: The USC-based BED and EQD2 doses of the macula, optic disc, and the lens were on average 118 ± 46% (p < 0.0527), 126 ± 43% (p < 0.0354), and 112 ± 32% (p < 0.0265) higher than those of I125-BT, respectively. The BED and EQD2 doses of the opposite retina were 52 ± 9% lower than I125-BT. The tumor SFED values were 25.2 ± 3.3 Gy and 29.1 ± 2.5 Gy when using USC and LQ models which can be delivered within 1 hour. All BED and EQD2 values using L-Q model were significantly larger when compared to the USC model (p < 0.0274) due to its large single fraction size (> 14 Gy). Conclusion: The estimated single fraction doses were feasible to be delivered within 1 hour using a high dose rate source such as electronic brachytherapy (eBT). However, the estimated OAR doses using eBT were 112 ∼ 118% higher than when using the I125-BT technique. Continued exploration of alternative dose rate or fractionation schedules should be followed.
CYCLING CURVES AND THEIR APPLICATIONS
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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.
Capelle, Pauline M; Semeniuk, Christina A D; Sopinka, Natalie M; Heath, John W; Love, Oliver P
2016-12-01
Prenatal exposure to elevated glucocorticoids can act as a signal of environmental stress, resulting in modifications to offspring phenotype. While "negative" phenotypic effects (i.e., smaller size, slower growth) are often reported, recent research coupling phenotype with other fitness-related traits has suggested positive impacts of prenatal stress. Using captive Chinook salmon (Oncorhynchus tshawytscha), we treated eggs with biologically relevant cortisol levels-low (300 ng mL(-1) ), high (1,000 ng mL(-1) ), or control (0 ng mL(-1) )-to examine the early-life impacts of maternally transferred stress hormones on offspring. Specifically, we measured early survival, rate of development, and multiple measures of morphology. Low and high cortisol dosing of eggs resulted in significantly higher survival compared to controls (37% and 24% higher, respectively). Fish reared from high dose eggs were structurally smaller compared to control fish, but despite this variation in structural size, exposure to elevated cortisol did not impact developmental rate. These results demonstrate that elevations in egg cortisol can positively influence offspring fitness through an increase in early survival while also altering phenotype at a critical life-history stage. Overall, these results suggest that exposure to prenatal stress may not always produce apparently negative impacts on offspring fitness and further proposes that complex phenotypic responses should be examined in relevant environmental conditions. © 2017 Wiley Periodicals, Inc.
Kim, Jin Joo; Kim, Jin You; Kang, Hyun Jung; Shin, Jong Ki; Kang, Taewoo; Lee, Seok Won; Bae, Young Tae
2017-07-01
Purpose To retrospectively investigate the relationship between the kinetic features of breast cancer assessed with computer-aided diagnosis (CAD) at preoperative magnetic resonance (MR) imaging and disease-free survival in patients with primary operable invasive breast cancer. Materials and Methods This retrospective study was approved by the institutional review board. The requirement to obtain informed consent was waived. The authors identified 329 consecutive women (mean age, 52.9 years; age range, 32-88 years) with newly diagnosed invasive breast cancer who had undergone preoperative MR imaging and surgery between January 2012 and February 2013. All MR images were retrospectively reviewed by using a commercially available CAD system, and the following kinetic parameters were noted for each lesion: peak enhancement (highest pixel signal intensity in the first series obtained after administration of contrast material), angio-volume (total volume of the enhancing lesion), and delayed enhancement profiles (the proportions of washout, plateau, and persistently enhancing component within a tumor). Cox proportional hazards modeling was used to identify the relationship between CAD-generated kinetics and disease-free survival after adjusting for clinical-pathologic variables. Results A total of 36 recurrences developed at a median follow-up of 50 months (range, 15-55 months). CAD-measured peak enhancement at preoperative MR imaging enabled differentiation between patients with and patients without recurrence (area under the receiver operating characteristic curve = 0.728; 95% confidence interval [CI]: 0.676, 0.775; P < .001). Multivariate Cox analysis showed that a higher peak enhancement (hazard ratio [HR] = 1.001; 95% CI: 1.000, 1.002; P = .004), a higher washout component (HR = 1.029; 95% CI: 1.005, 1.054; P = .017), and lymphovascular invasion at histopathologic examination (HR = 3.011; 95% CI: 1.302, 6.962; P = .010) were associated with poorer disease
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
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Bernstein, Daniel J.; Birkner, Peter; Lange, Tanja
2013-01-01
-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...
Martin, Georgianna LaNelle
2012-01-01
The purpose of this study was to understand how White students from low socioeconomic status backgrounds (operationalized as students who are both low income and of the first generation in their family to attend college) experience and navigate social class during college. This was a qualitative research study employing a phenomenological research…
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Jungwoo Shin
2018-02-01
Full Text Available Introduced autonomous and connected vehicles equipped with emerging technologies are expected to change the automotive market. In this study, using stated preference (SP data collected from choice experiments conducted in Korea with a mixed multiple discrete-continuous extreme value model (MDCEV, we analyzed how the advent of next-generation of vehicles with advanced vehicle technologies would affect consumer vehicle choices and usage patterns. Additionally, ex-ante market simulations and market segmentation analyses were conducted to provide specific management strategies for next-generation vehicles. The results showed that consumer preference structures of conventional and alternative fuel types primarily differed depending on whether they were drivers or non-drivers. Additionally, although the introduction of electric vehicles to the automobile market is expected to negatively affect the choice probability and mileage of other vehicles, it could have a positive influence on the probability of purchasing an existing conventional vehicle if advanced vehicle technologies are available.
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Uchiyama Masateru
2012-03-01
Full Text Available Abstract Background Interactions between the immune response and brain functions such as olfactory, auditory, and visual sensations are likely. This study investigated the effect of sounds on alloimmune responses in a murine model of cardiac allograft transplantation. Methods Naïve CBA mice (H2k underwent transplantation of a C57BL/6 (B6, H2b heart and were exposed to one of three types of music--opera (La Traviata, classical (Mozart, and New Age (Enya--or one of six different single sound frequencies, for 7 days. Additionally, we prepared two groups of CBA recipients with tympanic membrane perforation exposed to opera for 7 days and CBA recipients exposed to opera for 7 days before transplantation (pre-treatment. An adoptive transfer study was performed to determine whether regulatory cells were generated in allograft recipients. Immunohistochemical, cell-proliferation, cytokine, and flow cytometry assessments were also performed. Results CBA recipients of a B6 cardiac graft that were exposed to opera music and Mozart had significantly prolonged allograft survival (median survival times [MSTs], 26.5 and 20 days, respectively, whereas those exposed to a single sound frequency (100, 500, 1000, 5000, 10,000, or 20,000 Hz or Enya did not (MSTs, 7.5, 8, 9, 8, 7.5, 8.5 and 11 days, respectively. Untreated, CBA mice with tympanic membrane perforations and CBA recipients exposed to opera for 7 days before transplantation (pre-treatment rejected B6 cardiac grafts acutely (MSTs, 7, 8 and 8 days, respectively. Adoptive transfer of whole splenocytes, CD4+ cells, or CD4+CD25+ cells from opera-exposed primary allograft recipients resulted in significantly prolonged allograft survival in naive secondary recipients (MSTs, 36, 68, and > 100 days, respectively. Proliferation of splenocytes, interleukin (IL-2 and interferon (IFN-γ production was suppressed in opera-exposed mice, and production of IL-4 and IL-10 from opera-exposed transplant recipients increased
2012-01-01
Background Interactions between the immune response and brain functions such as olfactory, auditory, and visual sensations are likely. This study investigated the effect of sounds on alloimmune responses in a murine model of cardiac allograft transplantation. Methods Naïve CBA mice (H2k) underwent transplantation of a C57BL/6 (B6, H2b) heart and were exposed to one of three types of music--opera (La Traviata), classical (Mozart), and New Age (Enya)--or one of six different single sound frequencies, for 7 days. Additionally, we prepared two groups of CBA recipients with tympanic membrane perforation exposed to opera for 7 days and CBA recipients exposed to opera for 7 days before transplantation (pre-treatment). An adoptive transfer study was performed to determine whether regulatory cells were generated in allograft recipients. Immunohistochemical, cell-proliferation, cytokine, and flow cytometry assessments were also performed. Results CBA recipients of a B6 cardiac graft that were exposed to opera music and Mozart had significantly prolonged allograft survival (median survival times [MSTs], 26.5 and 20 days, respectively), whereas those exposed to a single sound frequency (100, 500, 1000, 5000, 10,000, or 20,000 Hz) or Enya did not (MSTs, 7.5, 8, 9, 8, 7.5, 8.5 and 11 days, respectively). Untreated, CBA mice with tympanic membrane perforations and CBA recipients exposed to opera for 7 days before transplantation (pre-treatment) rejected B6 cardiac grafts acutely (MSTs, 7, 8 and 8 days, respectively). Adoptive transfer of whole splenocytes, CD4+ cells, or CD4+CD25+ cells from opera-exposed primary allograft recipients resulted in significantly prolonged allograft survival in naive secondary recipients (MSTs, 36, 68, and > 100 days, respectively). Proliferation of splenocytes, interleukin (IL)-2 and interferon (IFN)-γ production was suppressed in opera-exposed mice, and production of IL-4 and IL-10 from opera-exposed transplant recipients increased compared to
Uchiyama, Masateru; Jin, Xiangyuan; Zhang, Qi; Hirai, Toshihito; Amano, Atsushi; Bashuda, Hisashi; Niimi, Masanori
2012-03-23
Interactions between the immune response and brain functions such as olfactory, auditory, and visual sensations are likely. This study investigated the effect of sounds on alloimmune responses in a murine model of cardiac allograft transplantation. Naïve CBA mice (H2k) underwent transplantation of a C57BL/6 (B6, H2b) heart and were exposed to one of three types of music--opera (La Traviata), classical (Mozart), and New Age (Enya)--or one of six different single sound frequencies, for 7 days. Additionally, we prepared two groups of CBA recipients with tympanic membrane perforation exposed to opera for 7 days and CBA recipients exposed to opera for 7 days before transplantation (pre-treatment). An adoptive transfer study was performed to determine whether regulatory cells were generated in allograft recipients. Immunohistochemical, cell-proliferation, cytokine, and flow cytometry assessments were also performed. CBA recipients of a B6 cardiac graft that were exposed to opera music and Mozart had significantly prolonged allograft survival (median survival times [MSTs], 26.5 and 20 days, respectively), whereas those exposed to a single sound frequency (100, 500, 1000, 5000, 10,000, or 20,000 Hz) or Enya did not (MSTs, 7.5, 8, 9, 8, 7.5, 8.5 and 11 days, respectively). Untreated, CBA mice with tympanic membrane perforations and CBA recipients exposed to opera for 7 days before transplantation (pre-treatment) rejected B6 cardiac grafts acutely (MSTs, 7, 8 and 8 days, respectively). Adoptive transfer of whole splenocytes, CD4+ cells, or CD4+CD25+ cells from opera-exposed primary allograft recipients resulted in significantly prolonged allograft survival in naive secondary recipients (MSTs, 36, 68, and > 100 days, respectively). Proliferation of splenocytes, interleukin (IL)-2 and interferon (IFN)-γ production was suppressed in opera-exposed mice, and production of IL-4 and IL-10 from opera-exposed transplant recipients increased compared to that from splenocytes of
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.
Ammer, Johannes; Sailer, Christian F; Riedle, Eberhard; Mayr, Herbert
2012-07-18
UV irradiation (266 or 280 nm) of benzhydryl triarylphosphonium salts Ar(2)CH-PAr(3)(+)X(-) yields benzhydryl cations Ar(2)CH(+) and/or benzhydryl radicals Ar(2)CH(•). The efficiency and mechanism of the photo-cleavage were studied by nanosecond laser flash photolysis and by ultrafast spectroscopy with a state-of-the-art femtosecond transient spectrometer. The influences of the photo-electrofuge (Ar(2)CH(+)), the photo-nucleofuge (PPh(3) or P(p-Cl-C(6)H(4))(3)), the counterion (X(-) = BF(4)(-), SbF(6)(-), Cl(-), or Br(-)), and the solvent (CH(2)Cl(2) or CH(3)CN) were investigated. Photogeneration of carbocations from Ar(2)CH-PAr(3)(+)BF(4)(-) or -SbF(6)(-) is considerably more efficient than from typical neutral precursors (e.g., benzhydryl chlorides or bromides). The photochemistry of phosphonium salts is controlled by the degree of ion pairing, which depends on the solvent and the concentration of the phosphonium salts. High yields of carbocations are obtained by photolyses of phosphonium salts with complex counterions (X(-) = BF(4)(-) or SbF(6)(-)), while photolyses of phosphonium halides Ar(2)CH-PPh(3)(+)X(-) (X(-) = Cl(-) or Br(-)) in CH(2)Cl(2) yield benzhydryl radicals Ar(2)CH(•) due to photo-electron transfer in the excited phosphonium halide ion pair. At low concentrations in CH(3)CN, the precursor salts are mostly unpaired, and the photo-cleavage mechanism is independent of the nature of the counter-anions. Dichloromethane is better suited for generating the more reactive benzhydryl cations than the more polar and more nucleophilic solvents CH(3)CN or CF(3)CH(2)OH. Efficient photo-generation of the most reactive benzhydryl cations (3,5-F(2)-C(6)H(3))(2)CH(+) and (4-(CF(3))-C(6)H(4))(2)CH(+) was only achieved using the photo-leaving group P(p-Cl-C(6)H(4))(3) and the counter-anion SbF(6)(-) in CH(2)Cl(2). The lifetimes of the photogenerated benzhydryl cations depend greatly on the decay mechanisms, which can be reactions with the solvent, with the photo
Survival analysis of orthodontic mini-implants.
Lee, Shin-Jae; Ahn, Sug-Joon; Lee, Jae Won; Kim, Seong-Hun; Kim, Tae-Woo
2010-02-01
Survival analysis is useful in clinical research because it focuses on comparing the survival distributions and the identification of risk factors. Our aim in this study was to investigate the survival characteristics and risk factors of orthodontic mini-implants with survival analyses. One hundred forty-one orthodontic patients (treated from October 1, 2000, to November 29, 2007) were included in this survival study. A total of 260 orthodontic mini-implants that had sandblasted (large grit) and acid-etched screw parts were placed between the maxillary second premolar and the first molar. Failures of the implants were recorded as event data, whereas implants that were removed because treatment ended and those that were not removed during the study period were recorded as censored data. A nonparametric life table method was used to visualize the hazard function, and Kaplan-Meier survival curves were generated to identify the variables associated with implant failure. Prognostic variables associated with implant failure were identified with the Cox proportional hazard model. Of the 260 implants, 22 failed. The hazard function for implant failure showed that the risk is highest immediately after placement. The survival function showed that the median survival time of orthodontic mini-implants is sufficient for relatively long orthodontic treatments. The Cox proportional hazard model identified that increasing age is a decisive factor for implant survival. The decreasing pattern of the hazard function suggested gradual osseointegration of orthodontic mini-implants. When implants are placed in a young patient, special caution is needed to lessen the increased probability of failure, especially immediately after placement.
Directory of Open Access Journals (Sweden)
René Pellissier
2012-01-01
Full Text Available This paper explores the notion ofjump ing the curve,following from Handy 's S-curve onto a new curve with new rules policies and procedures. . It claims that the curve does not generally lie in wait but has to be invented by leadership. The focus of this paper is the identification (mathematically and inferentially ofthat point in time, known as the cusp in catastrophe theory, when it is time to change - pro-actively, pre-actively or reactively. These three scenarios are addressed separately and discussed in terms ofthe relevance ofeach.
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 ...
Martínez, Sol Sáez; de la Rosa, Félix Martínez; Rojas, Sergio
2017-01-01
In Advanced Calculus, our students wonder if it is possible to graphically represent a tornado by means of a three-dimensional curve. In this paper, we show it is possible by providing the parametric equations of such tornado-shaped curves.
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
Directory of Open Access Journals (Sweden)
Simone Appenzeller
2005-08-01
the univariate analysis, male sex, infection and the use of cyclophosphamide were associated with death. In the multivariate regression, only male sex was related to death (odds ratio = 5.8. CONCLUSIONS: During a follow-up period of 27 years, death was observed in 21.8%. Although infection was directly responsible for half of the deaths, survival was not influenced by the presence of infection or renal insufficiency. Male sex was the only variable that influenced survival in this cohort. A greater attention should be given to boys with SLE in order to improve survival.
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.
Buonanno, Paolo; Fergusson, Leopoldo; Vargas, Juan Fernando
2014-01-01
We document the existence of a Crime Kuznets Curve in US states since the 1970s. As income levels have risen, crime has followed an inverted U-shaped pattern, first increasing and then dropping. The Crime Kuznets Curve is not explained by income inequality. In fact, we show that during the sample period inequality has risen monotonically with income, ruling out the traditional Kuznets Curve. Our finding is robust to adding a large set of controls that are used in the literature to explain the...
Applied survival analysis using R
Moore, Dirk F
2016-01-01
Applied Survival Analysis Using R covers the main principles of survival analysis, gives examples of how it is applied, and teaches how to put those principles to use to analyze data using R as a vehicle. Survival data, where the primary outcome is time to a specific event, arise in many areas of biomedical research, including clinical trials, epidemiological studies, and studies of animals. Many survival methods are extensions of techniques used in linear regression and categorical data, while other aspects of this field are unique to survival data. This text employs numerous actual examples to illustrate survival curve estimation, comparison of survivals of different groups, proper accounting for censoring and truncation, model variable selection, and residual analysis. Because explaining survival analysis requires more advanced mathematics than many other statistical topics, this book is organized with basic concepts and most frequently used procedures covered in earlier chapters, with more advanced topics...
Fast pyrolysis of switchgrass (and resultant biochar) can be used for bio-fuel production, soil amendments for fertilizing crops, binding heavy metals, and sequestering environmental biocarbon. To determine the influence of fast pyrolysis-generated switchgrass biochar on survival of foodborne path...
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.
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Villanueva, Héctor
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....
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.
Stankova-Frenkel, Z E
1997-01-01
We study the moduli of trigonal curves. We establish the exact upper bound of ${36(g+1)}/(5g+1)$ for the slope of trigonal fibrations. Here, the slope of any fibration $X\\to B$ of stable curves with smooth general member is the ratio Hodge class $\\lambda$ on the moduli space $\\bar{\\mathfrak{M}}_g$ to the base $B$. We associate to a trigonal family $X$ a canonical rank two vector bundle $V$, and show that for Bogomolov-semistable $V$ the slope satisfies the stronger inequality ${\\delta_B}/{\\lambda_B}\\leq 7+{6}/{g}$. We further describe the rational Picard group of the {trigonal} locus $\\bar{\\mathfrak T}_g$ in the moduli space $\\bar{\\mathfrak{M}}_g$ of genus $g$ curves. In the even genus case, we interpret the above Bogomolov semistability condition in terms of the so-called Maroni divisor in $\\bar{\\mathfrak T}_g$.
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Villanueva, Héctor
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...
Šumanović-Glamuzina, Darinka; Lozić, Bernarda; Iwanowski, Piotr S; Zemunik, Tatijana; Bilinovac, Zeljka; Stasiewicz-Jarocka, Beata; Panasiuk, Barbara; Midro, Alina T
2017-01-01
Carriership of a reciprocal chromosomal translocation (RCT) involving the short arm of chromosome 4 (4p) may result in birth of a child with Wolf-Hirschhorn syndrome (WHS) due to monosomy 4p, a priori modified by the impact of the partner chromosome imbalance. Familial transmission studies of RCT enable obtaining empirical risk figures that are essential for genetic counseling. In this study, pedigree data from carriers of a unique t(4;19)(p15.32;p13.3), ascertained by two children with WHS phenotype, were collected through five generations and empirical risk for different pregnancy outcomes was assessed. In addition, the phenotype-karyotype correlation was studied in two unbalanced children against the phenotypes of children (literature data) with pure monosomy 4p15.32 → pter and pure trisomy 19p13.3 → pter, accordingly. The phenotype analysis was conducted using the catalogue of traits according to the Munich Dysmorphology Database. Pedigree segregation analysis was conducted by the direct method according to Stengel- Rutkowski et al. A double segment imbalance, trisomy 19p13.3 → pter with monosomy 4p15.32 → pter, was diagnosed in WHS progeny at birth. No essential modification of WHS phenotype by the additional trisomy 19p was observed, except for a limited survivability (death in infancy). Pedigree segregation analysis covered 39 relatives showed the probability rate for liveborn with unbalanced karyotype of 3.7 ± 3.6% (1/27), for stillbirth/neonatal death at 7.4 ± 5.0% (2/27), for miscarriage at 22.2 ± 8.0% (6/27), for the chance of having a baby without unbalanced karyotype was estimated at 66.7 ± 9.1% (18/27). In addition, the value of 7.4% for genetic counseling for any carrier of RCT at risk for single segment 19p13.3 → pter imbalance at birth was evaluated as such value have not been estimated so far. Carriership of a t(4;19)(p15.32;p13.3) is at low risk for an unbalanced child at birth and for stillbirth/neonatal death but
Leslie, Mark; Holloway, Charles A
2006-01-01
When a company launches a new product into a new market, the temptation is to immediately ramp up sales force capacity to gain customers as quickly as possible. But hiring a full sales force too early just causes the firm to burn through cash and fail to meet revenue expectations. Before it can sell an innovative product efficiently, the entire organization needs to learn how customers will acquire and use it, a process the authors call the sales learning curve. The concept of a learning curve is well understood in manufacturing. Employees transfer knowledge and experience back and forth between the production line and purchasing, manufacturing, engineering, planning, and operations. The sales learning curve unfolds similarly through the give-and-take between the company--marketing, sales, product support, and product development--and its customers. As customers adopt the product, the firm modifies both the offering and the processes associated with making and selling it. Progress along the manufacturing curve is measured by tracking cost per unit: The more a firm learns about the manufacturing process, the more efficient it becomes, and the lower the unit cost goes. Progress along the sales learning curve is measured in an analogous way: The more a company learns about the sales process, the more efficient it becomes at selling, and the higher the sales yield. As the sales yield increases, the sales learning process unfolds in three distinct phases--initiation, transition, and execution. Each phase requires a different size--and kind--of sales force and represents a different stage in a company's production, marketing, and sales strategies. Adjusting those strategies as the firm progresses along the sales learning curve allows managers to plan resource allocation more accurately, set appropriate expectations, avoid disastrous cash shortfalls, and reduce both the time and money required to turn a profit.
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
Skilling, John
2004-04-01
The aim is to compute random samples from the posterior probability distribution for some object, modelled as a mixture distribution with a variable number of component "atoms", usually having relatively few attributes. We use a space-filling curve (specifically the Hilbert curve) to parameterise an atom's attributes by a single number, This simplifies the geometry, and we describe seven "engines" (LifeStory1&2, GuidedWalk, Leapfrog1&2, Chameleon1&2) for driving a MCMC exploration program. A binary variant of slice sampling underlies the engines.
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.
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...
DEFF Research Database (Denmark)
Gómez Arranz, Paula; 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)
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 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...
Indian Academy of Sciences (India)
painting and reading. Unlike most others he dislikes computers. Figure 1. Ritabrata Munshi. Introd uction. In the first part of the article (Resonance, Vol. 4, No.9 ) we proved the Jordan sepa.ration theorem which says that a simple closed curve in E2 separates it into at least two components. In this concluding part after some ...
Lawes, Jonathan F.
2013-01-01
Graphing polar curves typically involves a combination of three traditional techniques, all of which can be time-consuming and tedious. However, an alternative method--graphing the polar function on a rectangular plane--simplifies graphing, increases student understanding of the polar coordinate system, and reinforces graphing techniques learned…
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Georgieva Yankova, Ginka
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)
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...
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...
Power Curve Measurements, REWS
DEFF Research Database (Denmark)
Villanueva, Héctor; Gómez Arranz, Paula
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...
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.
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.
Energy Technology Data Exchange (ETDEWEB)
Groot, Loek [Utrecht University School of Economics (USE), Faculty of Law, Economics and Governance, Janskerkhof 12, 3512 BL Utrecht (Netherlands)
2010-01-15
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. (author)
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.
Multipulse phase resetting curves
Krishnan, Giri P.; Bazhenov, Maxim; Pikovsky, Arkady
2013-01-01
In this paper, we introduce and study systematically, in terms of phase response curves, the effect of dual-pulse excitation on the dynamics of an autonomous oscillator. Specifically, we test the deviations from linear summation of phase advances resulting from two small perturbations. We analytically derive a correction term, which generally appears for oscillators whose intrinsic dimensionality is >1. The nonlinear correction term is found to be proportional to the square of the perturbatio...
Caravelli, Francesco
2011-01-01
Quantum Graphity is an approach to quantum gravity based on a background independent formulation of condensed matter systems on graphs. We summarize recent results obtained on the notion of emergent geometry from the point of view of a particle hopping on the graph. We discuss the role of connectivity in emergent Lorentzian perturbations in a curved background and the Bose--Hubbard (BH) model defined on graphs with particular symmetries.
Thorne, K S
1993-01-01
This lecture reviews recent research on closed timelike curves (CTCS), including these questions: Do the laws of physics prevent CTCs from ever forming in classical spacetime? If so, by what physical mechanism are C'I‘Cs prevented? Can the laws of physics be adapted in any reasonable way to a. spacetime that contains C'I‘Cs, or do they necessarily give nonsense? What insights into quantum gravity can one gain by asking questions such as these?
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.
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.
Lieberwirth, Claudia; Wang, Yue; Jia, Xixi; Liu, Yan
2013-01-01
Motherhood has profound effects on physiology, neuronal plasticity, and behavior. We conducted a series of experiments to test the hypothesis that fatherhood, similarly to motherhood, affects brain plasticity (such as cell proliferation and survival) and various behaviors in the highly social prairie vole (Microtus ochrogaster). In Experiment 1, adult males were housed with their same-sex cage mate (control), single-housed (isolation), or housed with a receptive female to mate and produce offspring (father) for 6 weeks. Fatherhood significantly reduced cell survival (assessed by bromodeoxyuridine labeling), but not cell proliferation (assessed by Ki67 labeling), in the amygdala, dentate gyrus of the hippocampus, and ventromedial hypothalamus, suggesting that fatherhood affects brain plasticity. In Experiment 2, neither acute (20 min) nor chronic (20 min daily for 10 consecutive days) pup exposure altered cell proliferation or survival in the brain, but chronic pup exposure increased circulating corticosterone levels. These data suggest that reduced cell survival in the brain of prairie vole fathers was unlikely to be due to the level of pup exposure and display of paternal behavior, and may not be mediated by circulating corticosterone. The effects of fatherhood on various behaviors (including anxiety-like, depression-like, and social behaviors) were examined in Experiment 3. The data indicated that fatherhood increased anxiety- and depression-like behaviors as well as altered aggression and social recognition memory in male prairie voles. These results warrant further investigation of a possible link between brain plasticity and behavioral changes observed due to fatherhood. PMID:23899240
Energy Technology Data Exchange (ETDEWEB)
Knoedler, R.; Bossmann, H.P.
1992-03-12
The invention refers to a thermo-electric generator, whose main part is a sodium concentration cell. In conventional thermo-electric generators of this kind, the sodium moving from a hot space to a colder space must be transported back to the hot space via a circulation pipe and a pump. The purpose of the invention is to avoid the disadvantages of this return transport. According to the invention, the thermo-electric generator is supported so that it can rotate, so that the position of each space relative to its propinquity to the heat source can be changed at any time.
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.
Lieberwirth, Claudia; Wang, Yue; Jia, Xixi; Liu, Yan; Wang, Zuoxin
2013-01-01
Motherhood has profound effects on physiology, neuronal plasticity, and behavior. We conducted a series of experiments to test the hypothesis that fatherhood, similarly to motherhood, affects brain plasticity (such as cell proliferation and survival) and various behaviors in the highly social prairie vole (Microtus ochrogaster). In Experiment 1, adult males were housed with their same-sex cage mate (control), single-housed (isolation), or housed with a receptive female to mate and produce off...
Lieberwirth, Claudia; Wang, Yue; Jia, Xixi; Liu, Yan; Wang, Zuoxin
2013-11-01
Motherhood has profound effects on physiology, neuronal plasticity, and behavior. We conducted a series of experiments to test the hypothesis that fatherhood, similarly to motherhood, affects brain plasticity (such as cell proliferation and survival) and various behaviors in the highly social prairie vole (Microtus ochrogaster). In Experiment 1, adult males were housed with their same-sex cage mate (control), single-housed (isolation), or housed with a receptive female to mate and produce offspring (father) for 6 weeks. Fatherhood significantly reduced cell survival (assessed by bromodeoxyuridine labeling), but not cell proliferation (assessed by Ki67-labeling), in the amygdala, dentate gyrus of the hippocampus, and ventromedial hypothalamus, suggesting that fatherhood affects brain plasticity. In Experiment 2, neither acute (20 min) nor chronic (20 min daily for 10 consecutive days) pup exposure altered cell proliferation or survival in the brain, but chronic pup exposure increased circulating corticosterone levels. These data suggest that reduced cell survival in the brain of prairie vole fathers was unlikely to be due to the level of pup exposure and display of paternal behavior, and may not be mediated by circulating corticosterone. The effects of fatherhood on various behaviors (including anxiety-like, depression-like, and social behaviors) were examined in Experiment 3. The data indicated that fatherhood increased anxiety- and depression-like behaviors as well as altered aggression and social recognition memory in male prairie voles. These results warrant further investigation of a possible link between brain plasticity and behavioral changes observed due to fatherhood. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.
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.
Roc curves for continuous data
Krzanowski, Wojtek J
2009-01-01
Since ROC curves have become ubiquitous in many application areas, the various advances have been scattered across disparate articles and texts. ROC Curves for Continuous Data is the first book solely devoted to the subject, bringing together all the relevant material to provide a clear understanding of how to analyze ROC curves.The fundamental theory of ROC curvesThe book first discusses the relationship between the ROC curve and numerous performance measures and then extends the theory into practice by describing how ROC curves are estimated. Further building on the theory, the authors prese
Energy Technology Data Exchange (ETDEWEB)
Bossmann, H.P.; Knoedler, R.
1992-03-12
The invention refers to a thermo-electric generator, which contains sodium as the means of heat transport. The sodium moves from the space of higher temperature through a space into the space of lower temperature. One can do without a pump for transporting the sodium back from the space of lower temperature to the space of higher temperature, as the thermo-electric generator can rotate around an axis. It is therefore possible to interchange the position of the two spaces relative to the heat source.
Zhai, Xiaoqian; Luo, Tao; Peng, Xuan; Ma, Pengjiao; Wang, Chuhan; Zhang, Chunxi; Suo, Jing; Bao, Lang
2018-01-30
Genetic variations among genes of Mycobacterium tuberculosis may be associated with antigenic variation and immune evasion, which complicates the pathogenesis of M. tuberculosis. The hyper-virulent M. tuberculosis Beijing strains harbored several large sequence deletions, among which RD207 attributed to the deletion of CRISPR loci and several Cas genes. RD207 also gave rise to a truncated gene Rv2820c-Bj with 60% deletion in length at the 3'-end and a new 3'-end of five amino acid mutations. It has been reported that Rv2820c-Bj correlated with enhanced intracellular survival of M. smegmatis in macrophages when compared to its full-length counterpart Rv2820c in M. tuberculosis, however, the respective contribution of the truncation and the new 3'-end of Rv2820c-Bj to this enhancement was unclear. Here, by infecting THP-1 macrophages with Ms_Rv2820c-Bj, Ms_Rv2820c and MS_Rv2820c-Tr (expressing the truncated Rv2820c without five amino acid mutations at 3'-end), we found only Ms_Rv2820c-Bj was responsible for the enhancement of survival of M. smegmatis in macrophages. Furthermore, we detected that Ms_Rv2820c-Tr and Ms_Rv2820c-Bj induced similar cytokine profile and NO production after infection of macrophages, which was distinctly different from Ms_Rv2820c. However, Ms_Rv2820c-Bj evoked higher levels of interleukin-10 (IL-10) and lower levels of interleukin- 6 (IL-6), interleukin-1β (IL-1β) and interleukin-12 (IL-12) in infected THP-1 macrophages than Ms_Rv2820c-Tr. Accordingly, we concluded that the new 3'-end of Rv2820c-Bj was important to dampen host defense and enhance the intracellular survival of M. smegmatis. Copyright © 2017. Published by Elsevier B.V.
The Arithmetic of Elliptic Curves
Silverman, Joseph H
2009-01-01
Treats the arithmetic theory of elliptic curves in its modern formulation, through the use of basic algebraic number theory and algebraic geometry. This book discusses the necessary algebro-geometric results, and offers an exposition of the geometry of elliptic curves, and the formal group of an elliptic curve.
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.
Groot, S.P.C.
2002-01-01
Seeds are important for man, either as propagation material of crops or directly for the production of foods, fodder and drinks. The natural function of seeds is dispersal of its genes to successive generations. Survival mechanisms seed have evolved sometimes interfere with those preferred by
Multiwavelength light curve parameters of Cepheid variables
Directory of Open Access Journals (Sweden)
Bhardwaj Anupam
2017-01-01
Full Text Available We present a comparative analysis of theoretical and observed light curves of Cepheid variables using Fourier decomposition. The theoretical light curves at multiple wavelengths are generated using stellar pulsation models for chemical compositions representative of Cepheids in the Galaxy and Magellanic Clouds. The observed light curves at optical (VI, near-infrared (JHKs and mid-infrared (3.6 & 4.5-μm bands are compiled from the literature. We discuss the variation of light curve parameters as a function of period, wavelength and metallicity. Theoretical and observed Fourier amplitude parameters decrease with increase in wavelength while the phase parameters increase with wavelength. We find that theoretical amplitude parameters obtained using canonical mass-luminosity levels exhibit a greater offset with respect to observations when compared to non-canonical relations. We also discuss the impact of variation in convective efficiency on the light curve structure of Cepheid variables. The increase in mixing length parameter results in a zero-point offset in bolometric mean magnitudes and reduces the systematic large difference in theoretical amplitudes with respect to observations.
An efficient modified Elliptic Curve Digital Signature Algorithm | Kiros ...
African Journals Online (AJOL)
Many digital signatures which are based on Elliptic Curves Cryptography (ECC) have been proposed. Among these digital signatures, the Elliptic Curve Digital Signature Algorithm (ECDSA) is the widely standardized one. However, the verification process of ECDSA is slower than the signature generation process. Hence ...
Directory of Open Access Journals (Sweden)
Kai Willführ
Full Text Available OBJECTIVE: Functional trans-generational and parental effects are potentially important determinants of health in several mammals. For humans, the existing evidence is weak. We investigate whether disease exposure triggers functional trans-generational response effects among humans by analyzing siblings who were conceived under different disease loads, and comparing their mortality in later epidemics. Under functional trans-generational response mechanisms, we expect that those who were conceived under high pathogenic stress load will have relatively low mortality during a later epidemic. METHODS: We use data from the Registre de la Population du Québec Ancien, which covers the historical population living in St. Lawrence Valley, Québec, Canada. Children born in 1705-1724 were grouped according to their exposure during conception to the measles 1714-15 epidemic. The 1714-15 epidemic was followed by two mortality crises in 1729-1734. The cause of the first crises in 1729 is not exactly known. The second crisis in 1732 was caused by a smallpox epidemic. Using proportional hazard Cox regression models with multivariate adjustment and with fixed-effects approach that compare siblings, we analyze whether mortality in 1729-1734 is affected by exposure to the 1714-15 epidemic. RESULTS: Children who were conceived during the peak of the measles epidemic of 1714-15 exhibited significantly lower mortality during the 1729-1734 crisis than those who were born before the 1714-15 epidemic (mortality hazard ratio 0.106, p<.05 in multivariate adjusted models; 0.142 p<.1 in sibling comparison models. CONCLUSIONS: The results are consistent with a trans-generational mechanism that functionally responds to pathogen stress and suggest that early disease exposure may be protective later in life. Alternative explanations for the mortality patterns are discussed and shown to be problematic.
Directory of Open Access Journals (Sweden)
C. N. Baby Maheswari
2014-03-01
Full Text Available This article examines the complexities in the lives of African-Americans. It discusses the psycho-social challenges they faced in the twentieth century and their relentless efforts to attain, secure and define a sense of dignity to lead their lives. It also discusses the vulnerability of their existence and the sad dilemma in which the blacks were caught. The play has been deliberately selected for investigation as Lorrane Hansberry depicts, very skillfully, not only the gaps and inconsistencies of the two generations, but also the clashes in their aspirations and values. These struggles and clashes are epitomized in Walter and Mama Lena in the play and are discussed, from various perspectives, in the present article. Offering background to both the writer and the play, the article explores how Hansberry juxtaposes these ideas; that is, Mama finding the freedom to be sufficient for her happiness; where as, her children perceiving money as the new path to provide sense of happiness. The rebellion of Beneatha against the African-American value system and her rejection of the ideals of the family as well as the aspirations of younger generation for self- fulfillment, the sufferings of older generations, the pain of racial discrimination and the struggles for gaining the rights and dignity also form the very important topics of discussion in the paper.
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.
Miller, Rupert G
2011-01-01
A concise summary of the statistical methods used in the analysis of survival data with censoring. Emphasizes recently developed nonparametric techniques. Outlines methods in detail and illustrates them with actual data. Discusses the theory behind each method. Includes numerous worked problems and numerical exercises.
DEFF Research Database (Denmark)
Ashauer, Roman; Albert, Carlo; Augustine, Starrlight
2016-01-01
well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates...
Energy Technology Data Exchange (ETDEWEB)
Lovedy Singh, L., E-mail: lovedyo1@yahoo.co.in; Gartia, R.K.
2014-01-15
Highlights: • Use of Hybrid Genetic Algorithm in TL analysis. • Deconvolution in simplified OTOR equation. • Glow curve analysis. -- Abstract: A novel method of analyzing thermoluminescence TL glow curves is presented here. This method is based on the recently derived simplified OTOR equation. It employs the Hybrid Genetic Algorithm for the extraction of the TL parameters. This method has been tested against theoretical glow-curve data that were generated using the full iteration method without any prior approximation in the OTOR model, and it has also been tested using the complex glow curve of NaCl.
Advanced Online Survival Analysis Tool for Predictive Modelling in Clinical Data Science.
Montes-Torres, Julio; Subirats, José Luis; Ribelles, Nuria; Urda, Daniel; Franco, Leonardo; Alba, Emilio; Jerez, José Manuel
2016-01-01
One of the prevailing applications of machine learning is the use of predictive modelling in clinical survival analysis. In this work, we present our view of the current situation of computer tools for survival analysis, stressing the need of transferring the latest results in the field of machine learning to biomedical researchers. We propose a web based software for survival analysis called OSA (Online Survival Analysis), which has been developed as an open access and user friendly option to obtain discrete time, predictive survival models at individual level using machine learning techniques, and to perform standard survival analysis. OSA employs an Artificial Neural Network (ANN) based method to produce the predictive survival models. Additionally, the software can easily generate survival and hazard curves with multiple options to personalise the plots, obtain contingency tables from the uploaded data to perform different tests, and fit a Cox regression model from a number of predictor variables. In the Materials and Methods section, we depict the general architecture of the application and introduce the mathematical background of each of the implemented methods. The study concludes with examples of use showing the results obtained with public datasets.
Uchida, T.; Nakano, M.; Shoji, S.; Omata, T.; Harano, Y.; Nagata, Y.; Usui, Y.; Terachi, T.
2010-03-01
HIFU has been recognized as a minimally invasive treatment option for localized prostate cancer. The purpose of the study was to assess with a long-term outcome of HIFU for prostate cancer. From January 1999, a total of 657 patients who had HIFU with at least 2 year follow-up were treated with four different types of Sonablate® (Focus Surgery, Indianapolis, USA) devices. Thirty-three patients were treated with Sonablate® 200 (S200) from 1999 to 2001, 406 patients with Sonablate® 500 (S500) from 2001 to 2005, 200 patients with Sonablate® 500 version 4 (V4) from 2005-2008 and 19 patients with Sonablate® 500 TCM (TCM) from 2007. Biochemical disease-free survival rate (bDFS) in all patients was 59% in 8 years. bDFS in 8 years in patients with S200 and S500 groups were 55% and 56%, and bDFS in 4 and 2 years in patients with V4 and TCM group were 72% and 84%, respectively. bDFS in low, intermediate, and high risk groups were 75%, 54%, and 43% in S200/S500 and 93%, 72%, and 58% in V4/TCM group. Negative prostate biopsy rate after HIFU was 97% in S200, 79% in S500, 94% in V4 and 100% in TCM group. HIFU as primary therapy for prostate cancer is indicated in patients with low- and intermediate-risk (T1-T2b N0M0 disease, a Gleason score of ⩽7, a PSA level of <20 ng/mL) and a prostate volume of less than 40 mL. The rate of clinical outcome has significantly improved over the years due to technical improvements in the device.
S.E. Overbeek (Shelley); P.R. Rijnbeek (Peter); C. Vons; H.C. Hoogsteden (Henk); J.M. Bogaard (Jan); P.G.H. Mulder (Paul)
1996-01-01
textabstractMethacholine is frequently used to determine bronchial hyperresponsiveness (BHR) and to generate dose-response curves. These curves are characterized by a threshold (provocative concentration of methacholine producing a 20% fall in forced expiratory volume in one second
Variability of the Wind Turbine Power Curve
Directory of Open Access Journals (Sweden)
Mahesh M. Bandi
2016-09-01
Full Text Available Wind turbine power curves are calibrated by turbine manufacturers under requirements stipulated by the International Electrotechnical Commission to provide a functional mapping between the mean wind speed v ¯ and the mean turbine power output P ¯ . Wind plant operators employ these power curves to estimate or forecast wind power generation under given wind conditions. However, it is general knowledge that wide variability exists in these mean calibration values. We first analyse how the standard deviation in wind speed σ v affects the mean P ¯ and the standard deviation σ P of wind power. We find that the magnitude of wind power fluctuations scales as the square of the mean wind speed. Using data from three planetary locations, we find that the wind speed standard deviation σ v systematically varies with mean wind speed v ¯ , and in some instances, follows a scaling of the form σ v = C × v ¯ α ; C being a constant and α a fractional power. We show that, when applicable, this scaling form provides a minimal parameter description of the power curve in terms of v ¯ alone. Wind data from different locations establishes that (in instances when this scaling exists the exponent α varies with location, owing to the influence of local environmental conditions on wind speed variability. Since manufacturer-calibrated power curves cannot account for variability influenced by local conditions, this variability translates to forecast uncertainty in power generation. We close with a proposal for operators to perform post-installation recalibration of their turbine power curves to account for the influence of local environmental factors on wind speed variability in order to reduce the uncertainty of wind power forecasts. Understanding the relationship between wind’s speed and its variability is likely to lead to lower costs for the integration of wind power into the electric grid.
Energy Technology Data Exchange (ETDEWEB)
Hoff, Gabriela; Fischer, Andreia Caroline Fischer da Silveira; Accurso, Andre, E-mail: andreia.silveira.001@acad.pucrs.b, E-mail: andre.accurso@acad.pucrs.b [Pontificia Universidade Catolica do Rio Grande do Sul (PUC/RS), Porto Alegre, RS (Brazil). Grupo de Experimentacao e Simulacacao Computacional em Fisica Medica; Andrade, Jose Rodrigo Mendes, E-mail: jose.andrade@santacasa.tche.b [Irmandade da Santa Casa de Misericordia de Porto Alegre, RS (Brazil). Servico de Atencao a Saude e Qualidade de Vida; Bacelar, Alexandre, E-mail: abacelar@hcpa.ufrgs.b [Hospital de Clinicas de Porto Alegre, RS (Brazil). Setor de Fisica Medica e Radioprotecao
2011-10-26
This paper intended to measure iso expositions curves in areas of mobile equipment use. It was selected: a Shimadzu mobile equipment and two Siemens equipment, being used a non-anthropomorphic scatterer. The exposure measurements in mesh of 4.20 x 4.20 cubic centimeters, at a half-height of the simulator and steps of 30 cm, were used by using the radiographic techniques: 100 k Vp and 63 m As (Shimadzu) and 96 k Vp and 40 m As (Siemens). For estimation of environmental equivalent dose, during 12 months, were considered: 3.55 m As/examination and 44.5 procedures/month (adults): and 3.16 m As/examination and 20.1 procedures/month (pediatrics). It was observed that only the values in the distance of 60 cm presented over the maximum limit of environment equivalent dose defined for Free Area (0.5 mSv/year). The points collected at 2.1 m from the primary beam center, have shown to be always 12% of referred limit, shown to be a safe distance for the hospitalized patients
Logarithmic Spiral - A Splendid Curve
Indian Academy of Sciences (India)
I. In this article some properties of logarithmic spiral have been described along with the ap- pearance as well as applications of the curve in art and nature. After the discovery of anq,lytical geometry by Rene Des- cartes (1596-1650) in 1637, the custom of represent- ing various curves with the help of equations came into.
Space curves, anholonomy and nonlinearity
Indian Academy of Sciences (India)
vector at each point on the chain can be regarded as defining the local tangent to some space curve [6,7]. Clearly, it is possible to have moving space curves as well. This happens when a vortex filament, a polymer or an elastic rod is in motion. Again, as one changes some parameters in a dynamical system, a given phase.
Pulse Characteristic Curves of Vidicons,
microamps, and in vidicons with heterotransition screens, up to 10 microamps. The use of static modulation characteristic curves of vidicons for the...determination of the pulse beam current can lead to an error > 100%. With the help of pulse-modulation characteristic curves, it is possible to obtain the
Management of the learning curve
DEFF Research Database (Denmark)
Pedersen, Peter-Christian; Slepniov, Dmitrij
2016-01-01
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...
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...... on parametrization of immersions by B-splines, which ties in naturally with Isogeometric Analysis to solve the PDE. We give numerical examples of solutions, and compare the Riemannian optimization algorithms with different choices of metrics to a naive unregularized discretize-first approach....
Braun, S; Hnat, W P; Johnson, B E
1996-08-01
Through the use of a sophisticated measuring device and support computer technology, accurate arch circumferences were determined for 27 casts that exhibited moderate to severe curves of Spee. Arch circumference differences were subsequently obtained by comparing the measured arch length to a planar projection formed by the center of the incisal tips anteriorly and the distobuccal cusp tips of the second molars distally. A general relationship has been derived for the arch circumference differential, resulting from the elimination of the curve of Spee, versus the severity of the curve. The arch circumference reduction is considerably less than that found by earlier investigators, implying that the incisor protrusion often associated with leveling the curve of Spee is not primarily due to the aforementioned differential, but rather more directly due to the mechanics used in leveling the curve of Spee.
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
More Unusual Light Curves from Kepler
Kohler, Susanna
2017-03-01
-main-sequence stars ever obtained.In these light curves, Stauffer and collaborators found a set of 23 very low-mass, mid-to-late-type M dwarfs with unusual variability in their light curves. The variability is consistent with the stars rotation period where measured which suggests that whatever causes the dips in the light curve, its orbiting at the same rate as the star spins.Causes of Variability?These plots show how the properties of these 23 stars compare to those of the rest of the stars in their cluster (click for a closer look!). For all but the rotation rate, they are typical. But the stars with scallop-shaped light curves have among the shortest periods in Upper Sco, with somenear the theoretical break-up for stars of their age. [Stauffer et al. 2017]The authors categorize the 23 stars into two main groups.The first group consists of 19 stars with short periods; more than half of them rotate within a factor of two of their predicted breakup period! Many of these show sudden changes in their light-curve morphology, often after a stellar flare. The authors propose that the variability in these light curves might be caused by warm coronal gas clouds that are organized into a structured toroidal shape around the star.The second group consists of the remaining four stars, which have slightly longer periods. The light curves show a single short-duration flux dip with highly variable depth and shape superposed on normal, spotted-star light curves. The authors best guess for these four stars is that there are clouds of dusty debris circling the star, possibly orbiting a close-in planet or resulting from a recent collisional event.Stauffer and collaborators are currently developing more detailed models for these stars based on the possible variability scenarios. The next step, they state, is to determine if the gas in these structures have properties necessary to generate the light-curve features we see.CitationJohn Stauffer et al 2017 AJ 153 152. doi:10.3847/1538-3881/aa5eb9
Murre, Jaap M J
2014-04-01
In this article, learning curves for foreign vocabulary words are investigated, distinguishing between a subject-specific learning rate and a material-specific parameter that is related to the complexity of the items, such as the number of syllables. Two experiments are described, one with Turkish words and one with Italian words. In both, S-shaped learning curves were observed, which were most obvious if the subjects were not very familiar with the materials and if they were slow learners. With prolonged learning, the S shapes disappeared. Three different mathematical functions are proposed to explain these S-shaped curves. A further analysis clarifies why S-shaped learning curves may go unnoticed in many experiments.
Adesah, R. S.; Zakaria, R.; Wahab, A. F.; Talibe, A.
2017-09-01
The paper discusses about the formulation of type-2 fuzzy curve model. The generalization is carried out due to the existence of complex uncertainty which cannot be represented with classical type-1 fuzzy set. Hence, type-2 fuzzy set is proposed to define this type of complex uncertainty. Based on the complex uncertainty of data, fuzzy set theory type-2 with fuzzy number type-2 concept is used to represent the data with complex uncertainty. This process re-defines the data as type-2 fuzzy data which is also the result obtained by generalizing type-1 fuzzy data. Therefore, B-spline function is chosen to show the development of type-2 B-spline curve model via generalization. It is then followed by a number of processes, i.e. fuzzification, reduction and defuzzification are defined to model type-2 fuzzy B-spline curve to obtain a crisp type-2 fuzzy curve.
Directory of Open Access Journals (Sweden)
Jakub Tabas
2016-01-01
Full Text Available Innovations currently represent a tool of maintaining the going concern of a business entity and its competitiveness. However, effects of innovations are not infinite and if an innovation should constantly preserve a life of business entity, it has to be a continual chain of innovations, i.e. continual process. Effective live of a single innovation is limited while the limitation is derived especially from industry. The paper provides the results of research on innovations effects in the financial performance of small and medium-sized enterprises in the Czech Republic. Objective of this paper is to determine the length and intensity of the effects of technical innovations in company’s financial performance. The economic effect of innovations has been measured at application of company’s gross production power while the Deviation Analysis has been applied for three years’ time series. Subsequently the Survival Analysis has been applied. The analyses are elaborated for three statistical samples of SMEs constructed in accordance to the industry. The results obtained show significant differences in innovations’ survival within these three samples of enterprises then. The results are quite specific for the industries, and are confronted and discussed with the results of authors’ former research on the issue.
Flow over riblet curved surfaces
Energy Technology Data Exchange (ETDEWEB)
Loureiro, J B R; Freire, A P Silva, E-mail: atila@mecanica.ufrj.br [Mechanical Engineering Program, Federal University of Rio de Janeiro (COPPE/UFRJ), C.P. 68503, 21.941-972, Rio de Janeiro, RJ (Brazil)
2011-12-22
The present work studies the mechanics of turbulent drag reduction over curved surfaces by riblets. The effects of surface modification on flow separation over steep and smooth curved surfaces are investigated. Four types of two-dimensional surfaces are studied based on the morphometric parameters that describe the body of a blue whale. Local measurements of mean velocity and turbulence profiles are obtained through laser Doppler anemometry (LDA) and particle image velocimetry (PIV).
Active motion on curved surfaces
Castro-Villarreal, Pavel; Sevilla, Francisco J.
2017-01-01
A theoretical analysis of active motion on curved surfaces is presented in terms of a generalization of the Telegrapher's equation. Such generalized equation is explicitly derived as the polar approximation of the hierarchy of equations obtained from the corresponding Fokker-Planck equation of active particles diffusing on curved surfaces. The general solution to the generalized telegrapher's equation is given for a pulse with vanishing current as initial data. Expressions for the probability...
Modular forms and special cycles on Shimura curves (AM-161)
Kudla, Stephen S; Yang, Tonghai
2006-01-01
Modular Forms and Special Cycles on Shimura Curves is a thorough study of the generating functions constructed from special cycles, both divisors and zero-cycles, on the arithmetic surface ""M"" attached to a Shimura curve ""M"" over the field of rational numbers. These generating functions are shown to be the q-expansions of modular forms and Siegel modular forms of genus two respectively, valued in the Gillet-Soulé arithmetic Chow groups of ""M"". The two types of generating functions are related via an arithmetic inner product formula. In addition, an analogue of the classical Siegel-Weil
Curve Boxplot: Generalization of Boxplot for Ensembles of Curves.
Mirzargar, Mahsa; Whitaker, Ross T; Kirby, Robert M
2014-12-01
In simulation science, computational scientists often study the behavior of their simulations by repeated solutions with variations in parameters and/or boundary values or initial conditions. Through such simulation ensembles, one can try to understand or quantify the variability or uncertainty in a solution as a function of the various inputs or model assumptions. In response to a growing interest in simulation ensembles, the visualization community has developed a suite of methods for allowing users to observe and understand the properties of these ensembles in an efficient and effective manner. An important aspect of visualizing simulations is the analysis of derived features, often represented as points, surfaces, or curves. In this paper, we present a novel, nonparametric method for summarizing ensembles of 2D and 3D curves. We propose an extension of a method from descriptive statistics, data depth, to curves. We also demonstrate a set of rendering and visualization strategies for showing rank statistics of an ensemble of curves, which is a generalization of traditional whisker plots or boxplots to multidimensional curves. Results are presented for applications in neuroimaging, hurricane forecasting and fluid dynamics.
Parameter Deduction and Accuracy Analysis of Track Beam Curves in Straddle-type Monorail Systems
Directory of Open Access Journals (Sweden)
Xiaobo Zhao
2015-12-01
Full Text Available The accuracy of the bottom curve of a PC track beam is strongly related to the production quality of the entire beam. Many factors may affect the parameters of the bottom curve, such as the superelevation of the curve and the deformation of a PC track beam. At present, no effective method has been developed to determine the bottom curve of a PC track beam; therefore, a new technique is presented in this paper to deduce the parameters of such a curve and to control the accuracy of the computation results. First, the domain of the bottom curve of a PC track beam is assumed to be a spindle plane. Then, the corresponding supposed top curve domain is determined based on a geometrical relationship that is the opposite of that identified by the conventional method. Second, several optimal points are selected from the supposed top curve domain according to the dichotomy algorithm; the supposed top curve is thus generated by connecting these points. Finally, one rigorous criterion is established in the fractal dimension to assess the accuracy of the assumed top curve deduced in the previous step. If this supposed curve coincides completely with the known top curve, then the assumed bottom curve corresponding to the assumed top curve is considered to be the real bottom curve. This technique of determining the bottom curve of a PC track beam is thus proven to be efficient and accurate.
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.
Projection of curves on B-spline surfaces using quadratic reparameterization
Yang, Yijun
2010-09-01
Curves on surfaces play an important role in computer aided geometric design. In this paper, we present a hyperbola approximation method based on the quadratic reparameterization of Bézier surfaces, which generates reasonable low degree curves lying completely on the surfaces by using iso-parameter curves of the reparameterized surfaces. The Hausdorff distance between the projected curve and the original curve is controlled under the user-specified distance tolerance. The projected curve is T-G 1 continuous, where T is the user-specified angle tolerance. Examples are given to show the performance of our algorithm. © 2010 Elsevier Inc. All rights reserved.
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.
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 ...
Complexity of Curved Glass Structures
Kosić, T.; Svetel, I.; Cekić, Z.
2017-11-01
Despite the increasing number of research on the architectural structures of curvilinear forms and technological and practical improvement of the glass production observed over recent years, there is still a lack of comprehensive codes and standards, recommendations and experience data linked to real-life curved glass structures applications regarding design, manufacture, use, performance and economy. However, more and more complex buildings and structures with the large areas of glass envelope geometrically complex shape are built every year. The aim of the presented research is to collect data on the existing design philosophy on curved glass structure cases. The investigation includes a survey about how architects and engineers deal with different design aspects of curved glass structures with a special focus on the design and construction process, glass types and structural and fixing systems. The current paper gives a brief overview of the survey findings.
Elliptic curves a computational approach
Schmitt, Susanne; Pethö, Attila
2003-01-01
The basics of the theory of elliptic curves should be known to everybody, be he (or she) a mathematician or a computer scientist. Especially everybody concerned with cryptography should know the elements of this theory. The purpose of the present textbook is to give an elementary introduction to elliptic curves. Since this branch of number theory is particularly accessible to computer-assisted calculations, the authors make use of it by approaching the theory under a computational point of view. Specifically, the computer-algebra package SIMATH can be applied on several occasions. However, the book can be read also by those not interested in any computations. Of course, the theory of elliptic curves is very comprehensive and becomes correspondingly sophisticated. That is why the authors made a choice of the topics treated. Topics covered include the determination of torsion groups, computations regarding the Mordell-Weil group, height calculations, S-integral points. The contents is kept as elementary as poss...
Space filling curves in steganalysis
Westfeld, Andreas
2005-03-01
We introduce a new method to increase the reliability of current steganalytic techniques by optimising the sample order. Space filling curves (e.g., Hilbert curve) take advantage of the correlation of adjacent pixels and thus make the detection of steganographic messages with low change densities more reliable. The findings are applicable, but not limited to LSB steganalysis. An experimental comparison of five different sampling paths reveals that recursive principles achieve by far the best performance. All measures, such as mean distance, median autocorrelation, and the ability to detect even tiny modifications show substantial improvements compared to conventional methods. We elaborate the relationship between those parameters and quantify the effectiveness with a large test database of small images, which are usually hard to detect. Apart from quantitative advances, visualisation of steganalytic measures can also gain from the application of reverse space filling curves.
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.
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...
Holomorphic curves in loop groups
Energy Technology Data Exchange (ETDEWEB)
Guest, M.A.; Pressley, A.N.
1988-09-01
It was observed by Atiyah that there is a correspondence between based gauge equivalence classes of SU/sub n/-instantons over S/sup 4/ of charge d on the one hand, and based holomorphic curves of genus zero in ..cap omega..SU/sub n/ of degree d on the other hand. In this paper we study the parameter space of such holomorphic curves which have the additional property that they lie entirely in the subgroup ..cap omega../sub alg/SU/sub n/ of algebraic loops. We describe a cell decomposition of this parameter space, and compute its complex dimension to be (2n-1)d.
Section curve reconstruction and mean-camber curve extraction of a point-sampled blade surface.
Directory of Open Access Journals (Sweden)
Wen-long Li
Full Text Available The blade is one of the most critical parts of an aviation engine, and a small change in the blade geometry may significantly affect the dynamics performance of the aviation engine. Rapid advancements in 3D scanning techniques have enabled the inspection of the blade shape using a dense and accurate point cloud. This paper proposes a new method to achieving two common tasks in blade inspection: section curve reconstruction and mean-camber curve extraction with the representation of a point cloud. The mathematical morphology is expanded and applied to restrain the effect of the measuring defects and generate an ordered sequence of 2D measured points in the section plane. Then, the energy and distance are minimized to iteratively smoothen the measured points, approximate the section curve and extract the mean-camber curve. In addition, a turbine blade is machined and scanned to observe the curvature variation, energy variation and approximation error, which demonstrates the availability of the proposed method. The proposed method is simple to implement and can be applied in aviation casting-blade finish inspection, large forging-blade allowance inspection and visual-guided robot grinding localization.
The effect of pavement markings on driving behaviour in curves: a simulator study.
Ariën, Caroline; Brijs, Kris; Vanroelen, Giovanni; Ceulemans, Wesley; Jongen, Ellen M M; Daniels, Stijn; Brijs, Tom; Wets, Geert
2017-05-01
This study investigates the effect of two pavement markings (transverse rumble strips (TRS) and a backward pointing herringbone pattern (HP)) on speed and lateral control in and nearby curves. Two real-world curves with strong indications of a safety problem were replicated as realistic as possible in the simulator. Results show that both speed and lateral control differ between the curves. These behavioural differences are probably due to curve-related dissimilarities with respect to geometric alignment, cross-sectional design and speed limit. TRS and HP both influenced mean speed and mean acceleration/deceleration but not lateral control. TRS generated an earlier and more stable speed reduction than HP which induced significant speed reductions along the curve. The TRS gives drivers more time to generate the right expectations about the upcoming curve. When accidents occur primarily near the curve entry, TRS is recommended. The HP has the potential to reduce accidents at the curve end. Practitioner Summary: Two pavement markings (transversal rumble strips and HP) nearby dangerous curves were investigated in the driving simulator. TRS generated an earlier and more stable speed reduction than HP which induced speed reductions along the curve. The TRS gives drivers more time to generate right expectations about the upcoming curve.
[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.
Principal Curves on Riemannian Manifolds
DEFF Research Database (Denmark)
Hauberg, Søren
2015-01-01
from Hastie & Stuetzle to data residing on a complete Riemannian manifold. We show that for elliptical distributions in the tangent of spaces of constant curvature, the standard principal geodesic is a principal curve. The proposed model is simple to compute and avoids many of the pitfalls...
Murre, J.M.J.
2014-01-01
In this article, learning curves for foreign vocabulary words are investigated, distinguishing between a subject-specific learning rate and a material-specific parameter that is related to the complexity of the items, such as the number of syllables. Two experiments are described, one with Turkish
Clark, Robert D.; Webster-Clark, Daniel J.
2008-03-01
Two modifications to the standard use of receiver operating characteristic (ROC) curves for evaluating virtual screening methods are proposed. The first is to replace the linear plots usually used with semi-logarithmic ones (pROC plots), including when doing "area under the curve" (AUC) calculations. Doing so is a simple way to bias the statistic to favor identification of "hits" early in the recovery curve rather than late. A second suggested modification entails weighting each active based on the size of the lead series to which it belongs. Two weighting schemes are described: arithmetic, in which the weight for each active is inversely proportional to the size of the cluster from which it comes; and harmonic, in which weights are inversely proportional to the rank of each active within its class. Either scheme is able to distinguish biased from unbiased screening statistics, but the harmonically weighted AUC in particular emphasizes the ability to place representatives of each class of active early in the recovery curve.
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
Mentorship, learning curves, and balance.
Cohen, Meryl S; Jacobs, Jeffrey P; Quintessenza, James A; Chai, Paul J; Lindberg, Harald L; Dickey, Jamie; Ungerleider, Ross M
2007-09-01
Professionals working in the arena of health care face a variety of challenges as their careers evolve and develop. In this review, we analyze the role of mentorship, learning curves, and balance in overcoming challenges that all such professionals are likely to encounter. These challenges can exist both in professional and personal life. As any professional involved in health care matures, complex professional skills must be mastered, and new professional skills must be acquired. These skills are both technical and judgmental. In most circumstances, these skills must be learned. In 2007, despite the continued need for obtaining new knowledge and learning new skills, the professional and public tolerance for a "learning curve" is much less than in previous decades. Mentorship is the key to success in these endeavours. The success of mentorship is two-sided, with responsibilities for both the mentor and the mentee. The benefits of this relationship must be bidirectional. It is the responsibility of both the student and the mentor to assure this bidirectional exchange of benefit. This relationship requires time, patience, dedication, and to some degree selflessness. This mentorship will ultimately be the best tool for mastering complex professional skills and maturing through various learning curves. Professional mentorship also requires that mentors identify and explicitly teach their mentees the relational skills and abilities inherent in learning the management of the triad of self, relationships with others, and professional responsibilities.Up to two decades ago, a learning curve was tolerated, and even expected, while professionals involved in healthcare developed the techniques that allowed for the treatment of previously untreatable diseases. Outcomes have now improved to the point that this type of learning curve is no longer acceptable to the public. Still, professionals must learn to perform and develop independence and confidence. The responsibility to
Improvement of cam performance curve using B-Spline curve
Shahriman, A. B.; Syafiq, A. K. M.; Hashim, M. S. M.; Hazry, D.; Razlan, Z. M.; Wan, K.; Daud, R.; Cheng, E. M.; Zaaba, S. K.; Azizan, Azizi
2017-10-01
The mathematical modeling approach has been applied in order to increase the cam profile curve of Modenas CT115s performance by using MATLAB software as a programmed to calculate the mechanism of the cam profile. Cam is used inside the engine to push the rocker and consequently open and close the engine valve that allows the fuel-air mixture to be entered during the combustion process. The B-Spline curve was implemented in order to enhance the current performance of the cam profile. The calculation had been done by using manual and MATLAB software. The results obtained has been analyzed and interpreted in plotting the graphs. From the analysis, the profile that had the highest displacement factor, sk produced higher cam curve performance of the engine. Thus, it can be concluded that the increase of the displacement factor, sk can increase the engine performance as the valve displace further in which allow higher fuel-air mixture entrance during the combustion process.
An algorithm for estimating surface normal from its boundary curves
Directory of Open Access Journals (Sweden)
Jisoon Park
2015-01-01
Full Text Available Recently, along with the improvements of geometry modeling methods using sketch-based interface, there have been a lot of developments in research about generating surface model from 3D curves. However, surfacing a 3D curve network remains an ambiguous problem due to the lack of geometric information. In this paper, we propose a new algorithm for estimating the normal vectors of the 3D curves which accord closely with user intent. Bending energy is defined by utilizing RMF(Rotation-Minimizing Frame of 3D curve, and we estimated this minimal energy frame as the one that accords design intent. The proposed algorithm is demonstrated with surface model creation of various curve networks. The algorithm of estimating geometric information in 3D curves which is proposed in this paper can be utilized to extract new information in the sketch-based modeling process. Also, a new framework of 3D modeling can be expected through the fusion between curve network and surface creating algorithm.
ROC Curve Analysis in the Presence of Imperfect Reference Standards.
Liao, Peizhou; Wu, Hao; Yu, Tianwei
2017-06-01
The receiver operating characteristic (ROC) curve is an important tool for the evaluation and comparison of predictive models when the outcome is binary. If the class membership of the outcomes are known, ROC can be constructed for a model, and the ROC with greater area under the curve (AUC) indicates better performance. However in practice, imperfect reference standards often exist, in which class membership of every data point are not fully determined. This situation is especially prevalent in high-throughput biomedical data because obtaining perfect reference standards for all data points is either too costly or technically impractical. To construct ROC curves for these data, the common practice is to either ignore the uncertainties in references, or remove data points with high uncertainties. Such approaches may cause bias to the ROC curves and generate misleading results in method evaluation. Here we present a framework to incorporate membership uncertainties into the construction of ROC curve, termed the expected ROC or "eROC" curve. We develop an efficient procedure for the estimation of eROC curve. The advantages of using eROC are demonstrated using simulated and real data.
Symmetric digit sets for elliptic curve scalar multiplication without precomputation.
Heuberger, Clemens; Mazzoli, Michela
2014-08-28
We describe a method to perform scalar multiplication on two classes of ordinary elliptic curves, namely [Formula: see text] in prime characteristic [Formula: see text], and [Formula: see text] in prime characteristic [Formula: see text]. On these curves, the 4-th and 6-th roots of unity act as (computationally efficient) endomorphisms. In order to optimise the scalar multiplication, we consider a width- w -NAF (Non-Adjacent Form) digit expansion of positive integers to the complex base of τ , where τ is a zero of the characteristic polynomial [Formula: see text] of the Frobenius endomorphism associated to the curve. We provide a precomputationless algorithm by means of a convenient factorisation of the unit group of residue classes modulo τ in the endomorphism ring, whereby we construct a digit set consisting of powers of subgroup generators, which are chosen as efficient endomorphisms of the curve.
Marginal abatement cost curves for Heavy Duty Vehicles. Background report
Energy Technology Data Exchange (ETDEWEB)
Schroten, A.; Warringa, G.; Bles, M.
2012-09-15
Cost curves were calculated for CO2 abatement technologies for Heavy Duty Vehicles. These curves were elaborated for eight different vehicle categories (six categories of truck and two subcategories), as well as for an 'average' truck and bus. Given that cost curves depend very much on underlying assumptions, the MACH model (Marginal Abatement Costs of Heavy duty vehicles) was developed. This model allows users to enter their own assumptions with respect to parameters like fuel prices and cost and lifetime of individual technologies, with the model then generating new cost curves for the various vehicle categories. This background report contains a description of the model and a summary of the results of several model runs.
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.
Infinite swapping in curved spaces.
Curotto, E; Mella, Massimo
2014-01-07
We develop an extension of the infinite swapping and partial infinite swapping techniques [N. Plattner, J. D. Doll, P. Dupuis, H. Wang, Y. Liu, and J. E. Gubernatis, J. Chem. Phys. 135, 134111 (2011)] to curved spaces. Furthermore, we test the performance of infinite swapping and partial infinite swapping in a series of flat spaces characterized by the same potential energy surface model. We develop a second order variational algorithm for general curved spaces without the extended Lagrangian formalism to include holonomic constraints. We test the new methods by carrying out NVT classical ensemble simulations on a set of multidimensional toroids mapped by stereographic projections and characterized by a potential energy surface built from a linear combination of decoupled double wells shaped purposely to create rare events over a range of temperatures.
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.
Triangular Numbers and Elliptic Curves
Chahal, Jasbir S.; Top, Jaap
1996-01-01
Some arithmetic of elliptic curves and theory of elliptic surfaces is used to find all rational solutions (r, s, t) in the function field Q(m, n) of the pair of equations r(r + 1)/2 = ms(s + 1)/2 r(r + 1)/2 = nt(t + 1)/2. It turns out that infinitely many solutions exist. Several examples will be
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 (α95Belgium 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.
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.
Estimation of Curve Tracing Time in Supercapacitor based PV Characterization
Basu Pal, Sudipta; Das Bhattacharya, Konika; Mukherjee, Dipankar; Paul, Debkalyan
2017-08-01
Smooth and noise-free characterisation of photovoltaic (PV) generators have been revisited with renewed interest in view of large size PV arrays making inroads into the urban sector of major developing countries. Such practice has recently been observed to be confronted by the use of a suitable data acquisition system and also the lack of a supporting theoretical analysis to justify the accuracy of curve tracing. However, the use of a selected bank of supercapacitors can mitigate the said problems to a large extent. Assuming a piecewise linear analysis of the V-I characteristics of a PV generator, an accurate analysis of curve plotting time has been possible. The analysis has been extended to consider the effect of equivalent series resistance of the supercapacitor leading to increased accuracy (90-95%) of curve plotting times.
Smarandache curves according to Sabban frame for Darboux vector of Mannheim partner curve
Şenyurt, Süleyman; Altun, Yasin; Cevahir, Ceyda
2017-04-01
In this paper, we investigated special Smarandache curves belonging to Sabban frame drawn on the surface of the sphere by Darboux vector of Mannheim partner curve. We created Sabban frame belonging to this curve. It was explained Smarandache curves position vector is consisted by Sabban vectors belonging to this curve. Then, we calculated geodesic curvatures of this Smarandache curves. Found results were expressed depending on the Mannheim curve.
Synthesis and analysis of coupler curves with combined planar cam ...
African Journals Online (AJOL)
Cam and follower mechanisms are widely used to convert a rotary input motion into a controlled reciprocating or oscillating motion as output in machines or robots. As this mechanism has an ability to provide unlimited variety of output motions. Many works are done on the synthesis of coupler curves or path generation ...
Potential energy curves for neutral and multiply charged carbon ...
Indian Academy of Sciences (India)
Potential energy curves of various electronic states of CO+ (0 ≤ ≤ 6) are generated at MRCI/CASSCF level using cc-pvQZ basis set and the results are compared with available experimental and theoretical data. Author Affiliations. Pradeep Kumar1 N Sathyamurthy1 2 3. Department of Chemistry, Indian Institute of ...
Stress-Strain Curves for High-Performance Fiber Reinforced ...
African Journals Online (AJOL)
Steel fiber reinforced concrete (SFRC) is increasingly being used day by day as a structural material for various applications. The complete stress-strain curve of this material in compression is needed for the analysis and design of structural elements. An experimental investigation was carried out to generate the complete ...
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.
Energy Technology Data Exchange (ETDEWEB)
Som, P.M.; Lanzieri, C.F.; Sacher, M.; Lawson, W.; Biller, H.F.
1985-02-01
Combined conventional drip infusion-dynamic CT scanning was performed on 28 patients with clinically discovered neck or parapharyngeal space masses. Seventeen of these also had digital venous study or angiographic studies either to confirm the CT diagnosis or as part of an embolization procedure. The studies indicate that the initial portion of the dynamic scan curve can be characteristically classified as either an arterial, venous, or hypovascular signature curve. The current ideas of how these curves are generated, the specific appearance of these signature curves, and the types of pathologic conditions that correlate with each curve are discussed.
Leptogenesis from loop effects in curved spacetime
Energy Technology Data Exchange (ETDEWEB)
McDonald, Jamie I.; Shore, Graham M. [Department of Physics, Swansea University,Singleton Park, Swansea, SA2 8PP (United Kingdom)
2016-04-05
We describe a new mechanism — radiatively-induced gravitational leptogenesis — for generating the matter-antimatter asymmetry of the Universe. We show how quantum loop effects in C and CP violating theories cause matter and antimatter to propagate differently in the presence of gravity, and prove this is forbidden in flat space by CPT and translation symmetry. This generates a curvature-dependent chemical potential for leptons, allowing a matter-antimatter asymmetry to be generated in thermal equilibrium in the early Universe. The time-dependent dynamics necessary for leptogenesis is provided by the interaction of the virtual self-energy cloud of the leptons with the expanding curved spacetime background, which violates the strong equivalence principle and allows a distinction between matter and antimatter. We show here how this mechanism is realised in a particular BSM theory, the see-saw model, where the quantum loops involve the heavy sterile neutrinos responsible for light neutrino masses. We demonstrate by explicit computation of the relevant two-loop Feynman diagrams how the size of the radiative corrections relevant for leptogenesis becomes enhanced by increasing the mass hierarchy of the sterile neutrinos, and show how the induced lepton asymmetry may be sufficiently large to play an important rôle in determining the baryon-to-photon ratio of the Universe.
Leptogenesis from loop effects in curved spacetime
McDonald, Jamie I.; Shore, Graham M.
2016-04-01
We describe a new mechanism — radiatively-induced gravitational leptogenesis — for generating the matter-antimatter asymmetry of the Universe. We show how quantum loop effects in C and CP violating theories cause matter and antimatter to propagate differently in the presence of gravity, and prove this is forbidden in flat space by CPT and translation symmetry. This generates a curvature-dependent chemical potential for leptons, allowing a matter-antimatter asymmetry to be generated in thermal equilibrium in the early Universe. The time-dependent dynamics necessary for leptogenesis is provided by the interaction of the virtual self-energy cloud of the leptons with the expanding curved spacetime background, which violates the strong equivalence principle and allows a distinction between matter and antimatter. We show here how this mechanism is realised in a particular BSM theory, the see-saw model, where the quantum loops involve the heavy sterile neutrinos responsible for light neutrino masses. We demonstrate by explicit computation of the relevant two-loop Feynman diagrams how the size of the radiative corrections relevant for leptogenesis becomes enhanced by increasing the mass hierarchy of the sterile neutrinos, and show how the induced lepton asymmetry may be sufficiently large to play an important rôle in determining the baryon-to-photon ratio of the Universe.
Directory of Open Access Journals (Sweden)
Hassan Manal M
2009-02-01
Full Text Available Abstract Background Chronic hepatitis B virus (HBV and hepatitis C virus (HCV are established causes of HCC. HCC patients are often diagnosed late and receive palliative therapies, however, the survival of Asian American patients with HCC treated without transplantation has not been well studied. We reviewed our institution's experience to determine predictors and rates of survival in Asian American HCC patients treated without transplantation. Methods We identified Asian American patients with HCC referred to M. D. Anderson Cancer Center. Patients were tested for HBV and HCV. Survival curves were generated by Kaplan-Meier method. Multivariate Cox proportional hazards regression was used to test the relationship between prognostic factors and survival. Results Of 82 Asian American HCC patients, most had advanced disease (65% and received treatment (68%; however, only 11% had surgical resection. 94% had positive anti-HBc and 61% had positive HBsAg. 20% had positive anti-HCV. There were no significant changes in the rates of HBV and HCV over time. Male gender, high alpha-fetoprotein levels, and stage IV disease were associated with shorter survival Overall median survival was 9.2 months (95% CI 6.5–11.9, and the survival of HCV and HBV patients was not statistically different. Conclusion The survival rate of Asian American patients with advanced HCC, for whom transplantation was not available, was low. Timely hepatitis screening and interventions by primary care physicians may be the most logical solution to reduce the burden of hepatitis-associated HCC among Asian Americans.
Kuru, B
2011-04-01
The aims of the present study were to define the prognostic factors for locoregional recurrence (LRR) and survival in stage IIIC breast carcinoma as well as to examine the impact of adjuvant radiotherapy on the outcome of the disease. The records of 586 consecutive patients with stage IIIC breast carcinoma who underwent modified radical mastectomy were evaluated, and the prognostic factors for LRR and survival were analysed. Survival curves were generated using the Kaplan-Meier method, and multivariate analysis was performed using the Cox proportional hazard model. Five-year LRR and survival of stage IIIC breast carcinoma were 15 percent and 41.3 percent, respectively. Five-year LRR was significantly lower and five-year survival was significantly higher for all patients as well as for T1-2 patients with one to three apical node involvements who were treated with adjuvant radiotherapy. In multivariate analysis, apical node involvement, age below 35 years, T4 tumour, grade 3, extracapsular extension and lymphovascular invasion decreased survival, whereas adjuvant tamoxifen and adjuvant radiotherapy (risk ratio [RR] 0.51, 95 percent confidence interval [CI] 0.39-0.67) increased survival. Adjuvant radiotherapy was the sole independent factor that was found to be significantly associated with decreased LRR (RR 0.25, 95 percent CI 0.16-0.38). Radiotherapy decreased LRR and increased survival significantly in all stage IIIC patients and in the subgroup of T1-2 patients with one to three apical node involvements. Thus, it should be considered in the treatment of stage IIIC breast carcinoma.
Curved microchannels and bacterial streamers
Rusconi, Roberto; Lecuyer, Sigolene; Guglielmini, Laura; Stone, Howard
2010-03-01
Bacterial biofilms are commonly identified as microbial communities attached to a surface and encased in a self-secreted extracellular matrix. Due to their increased resistance to antimicrobial agents, biofilms have an enormous impact on health and medicine (e.g., wound healing, implant-associated infections, disease transmission). On the other hand, they constitute a major component of the stream ecosystem by increasing transport of nutrients and retention of suspended particles. In this talk, we present an experimental study of bacterial biofilm development in a microfluidic device. In particular, we show the formation of filamentous structures, or streamers, in curved channels and how these suspended biofilms are linked to the underlying hydrodynamics.
Reconfigurable Double-Curved Mould
DEFF Research Database (Denmark)
Raun, Christian; Kirkegaard, Poul Henning
2012-01-01
, double curved surfaces like facades or walls, where the curvature of each element is relatively small in comparison to the overall shape. In the proposed dynamic mould system, where only a set of points is defined, a stiff membrane interpolates the surface between points. To function as a surface...... suitable for casting concrete or other substances against without the need for further manual treatment, the membrane should be durable and maintain a perfectly smooth and non-porous surface as well. A membrane with these properties has been developed for this project, and it is the core of the dynamic...
General investigations of curved surfaces
Gauss, Karl Friedrich; Morehead, James
2005-01-01
Gauss's theory of surfaces is among the purely mathematical achievements inspired by ideas that arose in connection with surveys of the surface of the earth. Long regarded as a masterpiece in content and form, this work features one of the author's most original contributions to mathematics--the discovery that Gauss termed the ""Theorema Egregium."" It consists of his penetrating definition of the concept of surface curvature and the theorem that the ""Gauss curvature"" is invariant under arbitrary isometric deformation of a curved surface. The profound effects of these concepts were soon gene
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.
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
DECIPHERING THERMAL PHASE CURVES OF DRY, TIDALLY LOCKED TERRESTRIAL PLANETS
Energy Technology Data Exchange (ETDEWEB)
Koll, Daniel D. B.; Abbot, Dorian S., E-mail: dkoll@uchicago.edu [Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637 (United States)
2015-03-20
Next-generation space telescopes will allow us to characterize terrestrial exoplanets. To do so effectively it will be crucial to make use of all available data. We investigate which atmospheric properties can, and cannot, be inferred from the broadband thermal phase curve of a dry and tidally locked terrestrial planet. First, we use dimensional analysis to show that phase curves are controlled by six nondimensional parameters. Second, we use an idealized general circulation model to explore the relative sensitivity of phase curves to these parameters. We find that the feature of phase curves most sensitive to atmospheric parameters is the peak-to-trough amplitude. Moreover, except for hot and rapidly rotating planets, the phase amplitude is primarily sensitive to only two nondimensional parameters: (1) the ratio of dynamical to radiative timescales and (2) the longwave optical depth at the surface. As an application of this technique, we show how phase curve measurements can be combined with transit or emission spectroscopy to yield a new constraint for the surface pressure and atmospheric mass of terrestrial planets. We estimate that a single broadband phase curve, measured over half an orbit with the James Webb Space Telescope, could meaningfully constrain the atmospheric mass of a nearby super-Earth. Such constraints will be important for studying the atmospheric evolution of terrestrial exoplanets as well as characterizing the surface conditions on potentially habitable planets.
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.
Cognitive function in families with exceptional survival
DEFF Research Database (Denmark)
Barral, Sandra; Cosentino, Stephanie; Costa, Rosann
2012-01-01
members in the offspring generation demonstrate significantly better performance on multiple tasks requiring attention, working memory, and semantic processing when compared with individuals without a family history of exceptional survival, suggesting that cognitive performance may serve as an important...
The dChip survival analysis module for microarray data
Directory of Open Access Journals (Sweden)
Minvielle Stéphane
2011-03-01
Full Text Available Abstract Background Genome-wide expression signatures are emerging as potential marker for overall survival and disease recurrence risk as evidenced by recent commercialization of gene expression based biomarkers in breast cancer. Similar predictions have recently been carried out using genome-wide copy number alterations and microRNAs. Existing software packages for microarray data analysis provide functions to define expression-based survival gene signatures. However, there is no software that can perform survival analysis using SNP array data or draw survival curves interactively for expression-based sample clusters. Results We have developed the survival analysis module in the dChip software that performs survival analysis across the genome for gene expression and copy number microarray data. Built on the current dChip software's microarray analysis functions such as chromosome display and clustering, the new survival functions include interactive exploring of Kaplan-Meier (K-M plots using expression or copy number data, computing survival p-values from the log-rank test and Cox models, and using permutation to identify significant chromosome regions associated with survival. Conclusions The dChip survival module provides user-friendly way to perform survival analysis and visualize the results in the context of genes and cytobands. It requires no coding expertise and only minimal learning curve for thousands of existing dChip users. The implementation in Visual C++ also enables fast computation. The software and demonstration data are freely available at http://dchip-surv.chenglilab.org.
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.
Logging and Agricultural Residue Supply Curves for the Pacific Northwest
Energy Technology Data Exchange (ETDEWEB)
Kerstetter, James D.; Lyons, John Kim
2001-01-01
This report quantified the volume of logging residues at the county level for current timber harvests. The cost of recovering logging residues was determined for skidding, yearding, loading, chipping and transporting the residues. Supply curves were developed for ten candidate conversion sites in the Pacific Northwest Region. Agricultural field residues were also quantified at the county level using five-year average crop yields. Agronomic constraints were applied to arrive at the volumes available for energy use. Collection costs and transportation costs were determined and supply curves generated for thirteen candidate conversion sites.
Classical black holes: the nonlinear dynamics of curved spacetime.
Thorne, Kip S
2012-08-03
Numerical simulations have revealed two types of physical structures, made from curved spacetime, that are attached to black holes: tendexes, which stretch or squeeze anything they encounter, and vortexes, which twist adjacent inertial frames relative to each other. When black holes collide, their tendexes and vortexes interact and oscillate (a form of nonlinear dynamics of curved spacetime). These oscillations generate gravitational waves, which can give kicks up to 4000 kilometers per second to the merged black hole. The gravitational waves encode details of the spacetime dynamics and will soon be observed and studied by the Laser Interferometer Gravitational Wave Observatory and its international partners.
Global expression for representing cohesive-energy curves. II
Schlosser, Herbert; Ferrante, John
1993-01-01
Schlosser et al. (1991) showed that the R dependence of the cohesive energy of partially ionic solids may be characterized by a two-term energy relationship consisting of a Coulomb term arising from the charge transfer, delta-Z, and a scaled universal energy function, E*(a *), which accounts for the partially covalent character of the bond and for repulsion between the atomic cores for small R; a* is a scaled length. In the paper by Schlosser et al., the normalized cohesive-energy curves of NaCl-structure alkali-halide crystals were generated with this expression. In this paper we generate the cohesive-energy curves of several families of partially ionic solids with different crystal structures and differing degrees of ionicity. These include the CsCl-structure Cs halides, and the Tl and Ag halides, which have weaker ionic bonding than the alkali halides, and which have the CsCl and NaCl structures, respectively. The cohesive-energy-curve parameters are then used to generate theoretical isothermal compression curves for the Li, Na, K, Cs, and Ag halides. We find good agreement with the available experimental compression data.
Piccioli, Andrea; Spinelli, M Silvia; Forsberg, Jonathan A; Wedin, Rikard; Healey, John H; Ippolito, Vincenzo; Daolio, Primo Andrea; Ruggieri, Pietro; Maccauro, Giulio; Gasbarrini, Alessandro; Biagini, Roberto; Piana, Raimondo; Fazioli, Flavio; Luzzati, Alessandro; Di Martino, Alberto; Nicolosi, Francesco; Camnasio, Francesco; Rosa, Michele Attilio; Campanacci, Domenico Andrea; Denaro, Vincenzo; Capanna, Rodolfo
2015-05-22
We recently developed a clinical decision support tool, capable of estimating the likelihood of survival at 3 and 12 months following surgery for patients with operable skeletal metastases. After making it publicly available on www.PATHFx.org , we attempted to externally validate it using independent, international data. We collected data from patients treated at 13 Italian orthopaedic oncology referral centers between 2010 and 2013, then applied to PATHFx, which generated a probability of survival at three and 12-months for each patient. We assessed accuracy using the area under the receiver-operating characteristic curve (AUC), clinical utility using Decision Curve Analysis (DCA), and compared the Italian patient data to the training set (United States) and first external validation set (Scandinavia). The Italian dataset contained 287 records with at least 12 months follow-up information. The AUCs for the three-month and 12-month estimates was 0.80 and 0.77, respectively. There were missing data, including the surgeon's estimate of survival that was missing in the majority of records. Physiologically, Italian patients were similar to patients in the training and first validation sets. However notable differences were observed in the proportion of those surviving three and 12-months, suggesting differences in referral patterns and perhaps indications for surgery. PATHFx was successfully validated in an Italian dataset containing missing data. This study demonstrates its broad applicability to European patients, even in centers with differing treatment philosophies from those previously studied.
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...
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. .
Parametrizations of elliptic curves by Shimura curves and by classical modular curves
Ribet, Kenneth A.; Takahashi, Shuzo
1997-01-01
Fix an isogeny class 𝒜 of semistable elliptic curves over Q. The elements of 𝒜 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 X0D(N/D), whose Jacobian is isogenous to an abelian subvariety of J0(N). There is a unique A ∈ 𝒜 for which one has a nonconstant map πD : X0D(N/D) → A whose pullback A → Pic0(X0D(N/D)) is injective. The degree of πD is an integer δD which depends only on D (and the fixed isogeny class 𝒜). We investigate the behavior of δD as D varies. PMID:11607751
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.
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.
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.
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 ...
M-curves and symmetric products
Indian Academy of Sciences (India)
Indranil Biswas
2017-08-03
Aug 3, 2017 ... is bounded above by g + 1, where g is the genus of X [11]. Curves which have exactly the maximum number (i.e., genus +1) of components of the real part are called M-curves. Classifying real algebraic curves up to homeomorphism is straightforward, however, classifying even planar non-singular real ...
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
Optimal investment in learning-curve technologies
Della Seta, M.; Gryglewicz, S.; Kort, P.M.
2012-01-01
We study optimal investment in technologies characterized by the learning curve. There are two investment patterns depending on the shape of the learning curve. If the learning process is slow, firms invest relatively late and on a larger scale. If the curve is steep, firms invest earlier and on a
A method for the analysis of sigmoid stimulus-response curves.
Leppard, P; Faris, I; Jamieson, G G; Ludbrook, J
1979-02-01
This paper describes a method, using an interactive computer programme, for fitting a curve to data which is expected to assume a sigmoid form. The programme is specifically designed to generate best estimates of the limits and maximum slope of stimulus-response curves for the carotid sinus baroreceptor reflex, but is applicable to curve-fitting tasks in other fields such as immunology, pharmacology, biochemistry and neurophysiology.
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.
The average receiver operating characteristic curve in multireader multicase imaging studies.
Chen, W; Samuelson, F W
2014-08-01
In multireader, multicase (MRMC) receiver operating characteristic (ROC) studies for evaluating medical imaging systems, the area under the ROC curve (AUC) is often used as a summary metric. Owing to the limitations of AUC, plotting the average ROC curve to accompany the rigorous statistical inference on AUC is recommended. The objective of this article is to investigate methods for generating the average ROC curve from ROC curves of individual readers. We present both a non-parametric method and a parametric method for averaging ROC curves that produce a ROC curve, the area under which is equal to the average AUC of individual readers (a property we call area preserving). We use hypothetical examples, simulated data and a real-world imaging data set to illustrate these methods and their properties. We show that our proposed methods are area preserving. We also show that the method of averaging the ROC parameters, either the conventional bi-normal parameters (a, b) or the proper bi-normal parameters (c, da), is generally not area preserving and may produce a ROC curve that is intuitively not an average of multiple curves. Our proposed methods are useful for making plots of average ROC curves in MRMC studies as a companion to the rigorous statistical inference on the AUC end point. The software implementing these methods is freely available from the authors. METHODS for generating the average ROC curve in MRMC ROC studies are formally investigated. The area-preserving criterion we defined is useful to evaluate such methods.
Page curves for tripartite systems
Hwang, Junha; Lee, Deok Sang; Nho, Dongju; Oh, Jeonghun; Park, Hyosub; Yeom, Dong-han; Zoe, Heeseung
2017-07-01
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.
Simulations of Closed Timelike Curves
Brun, Todd A.; Wilde, Mark M.
2017-03-01
Proposed models of closed timelike curves (CTCs) have been shown to enable powerful information-processing protocols. We examine the simulation of models of CTCs both by other models of CTCs and by physical systems without access to CTCs. We prove that the recently proposed transition probability CTCs (T-CTCs) are physically equivalent to postselection CTCs (P-CTCs), in the sense that one model can simulate the other with reasonable overhead. As a consequence, their information-processing capabilities are equivalent. We also describe a method for quantum computers to simulate Deutschian CTCs (but with a reasonable overhead only in some cases). In cases for which the overhead is reasonable, it might be possible to perform the simulation in a table-top experiment. This approach has the benefit of resolving some ambiguities associated with the equivalent circuit model of Ralph et al. Furthermore, we provide an explicit form for the state of the CTC system such that it is a maximum-entropy state, as prescribed by Deutsch.
Is the tautochrone curve unique?
Terra, Pedro; Farina, C
2016-01-01
The answer to this question is no. In fact, in addition to the solution first obtained by Christiaan Huygens in 1658, given by the cycloid, we show that there is an infinite number of tautochrone curves. With this goal, we start by briefly reviewing an the problem of finding out the possible potential energies that lead to periodic motions of a particle whose period is a given function of its mechanical energy. There are infinitely many solutions, called sheared potentials. As an interesting example, we show that a P\\"oschl-Teller and the one-dimensional Morse potentials are sheared relative to one another for negative energies, clarifying why they share the same periods of oscillations for their bounded solutions. We then consider periodic motions of a particle sliding without friction over a track around its minimum under the influence of an uniform gravitational field. After a brief historical survey of the tautochrone problem we show that, given the period of oscillations, there is an infinity of tracks w...
A study of atypical APTT derivative curves on the ACL TOP coagulation analyser.
Solano, C; Zerafa, P; Bird, R
2011-02-01
The graphical representation of clotting data can provide useful information. A novel feature of the ACL TOP software allows display of clot reaction curves with superimposed first and second derivative curves. We noted atypical derivative plots associated with normal 'S'-shaped clot reaction curves in some abnormal activated partial thromboplastin time (APTT). We tested 179 citrate plasmas with four different APTT reagents on the ACL TOP. We documented the prevalence and utility of these APTT atypical derivative curves in these patients. Ellagic acid APTT reagents commonly produce atypical derivative curves despite normal 'S'-shaped clot reaction curves. Occasionally, these atypical second derivative curves may cause incorrect APTT results. With silica activator APTT reagents, atypical derivative curves were associated with genuine coagulation abnormalities such as single factor deficiencies and lupus anticoagulants (LAs). To our knowledge, this novel finding has not been reported. Atypical derivative curves seen in ellagic acid APTTs are of limited diagnostic use because of the frequency with which they occur. This may be related to the need to optimize the data reduction utilized on the ACL TOP for these reagents. With silica activator APTTs, the presence of atypical derivative curves proved to be a very simple tool when troubleshooting unexpected abnormal APTT results, commonly predicting a factor deficiency or LA that would warrant further investigation. The cause of these aberrant derivative curves is probably related to abnormal thrombin generation in the APTT test and warrants further study. © 2010 Blackwell Publishing Ltd.
Forces in the complex octonion curved space
Weng, Zi-Hua
2016-01-01
The paper aims to extend major equations in the electromagnetic and gravitational theories from the flat space into the complex octonion curved space. Maxwell applied simultaneously the quaternion analysis and vector terminology to describe the electromagnetic theory. It inspires subsequent scholars to study the electromagnetic and gravitational theories with the complex quaternions/octonions. Furthermore Einstein was the first to depict the gravitational theory by means of tensor analysis and curved four-space-time. Nowadays some scholars investigate the electromagnetic and gravitational properties making use of the complex quaternion/octonion curved space. From the orthogonality of two complex quaternions, it is possible to define the covariant derivative of the complex quaternion curved space, describing the gravitational properties in the complex quaternion curved space. Further it is possible to define the covariant derivative of the complex octonion curved space by means of the orthogonality of two comp...
Probabilistic Lane Estimation using Basis Curves
Huang, Albert S.; Teller, Seth
2010-01-01
Lane estimation for autonomous driving can be formulated as a curve estimation problem, where local sensor data provides partial and noisy observations of spatial curves. The number of curves to estimate may be initially unknown and many of the observations may be outliers or false detections (due e.g. to to tree shadows or lens flare). The challenges lie in detecting lanes when and where they exist, and updating lane estimates as new observations are made. This paper ...
Efficient detection of symmetries polynomially parametrized curves
Alcázar Arribas, Juan Gerardo
2014-01-01
We present efficient algorithms for detecting central and mirror symmetry for the case of algebraic curves defined by means of polynomial parametrizations. The algorithms are based on an algebraic relationship between proper parametrizations of a same curve, which leads to a triangular polynomial system that can be solved in a very fast way; in particular, curves parametrized by polynomials of serious degrees/coefficients can be analyzed in a few seconds. In our analysis we provide a good num...
Sieving for rational points on hyperelliptic curves
Siksek, Samir
2001-01-01
We give a new and efficient method of sieving for rational points\\ud on hyperelliptic curves. This method is often successful in proving that a\\ud given hyperelliptic curve, suspected to have no rational points, does in fact\\ud have no rational points; we have often found this to be the case even when our\\ud curve has points over all localizations Qp. We illustrate the practicality of the\\ud method with some examples of hyperelliptic curves of genus 1.
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...
Algebraic curves and one-dimensional fields
Bogomolov, Fedor
2002-01-01
Algebraic curves have many special properties that make their study particularly rewarding. As a result, curves provide a natural introduction to algebraic geometry. In this book, the authors also bring out aspects of curves that are unique to them and emphasize connections with algebra. This text covers the essential topics in the geometry of algebraic curves, such as line and vector bundles, the Riemann-Roch Theorem, divisors, coherent sheaves, and zeroth and first cohomology groups. The authors make a point of using concrete examples and explicit methods to ensure that the style is clear an
A Probabilistic Framework for Curve Evolution
DEFF Research Database (Denmark)
Dahl, Vedrana Andersen
2017-01-01
In this work, we propose a nonparametric probabilistic framework for image segmentation using deformable models. We estimate an underlying probability distributions of image features from regions defined by a deformable curve. We then evolve the curve such that the distance between the distributi......In this work, we propose a nonparametric probabilistic framework for image segmentation using deformable models. We estimate an underlying probability distributions of image features from regions defined by a deformable curve. We then evolve the curve such that the distance between...
On enumeration of Hilbert-like curves
Smrek, Jan; Y Grosberg, Alexander
2015-05-01
We present an analytical method to explicitly enumerate all self-similar space-filling curves similar to Hilbert curve, and find their number grows with length L as {{Z}L}∼ {{1.35699}L}. This presents a first step in the exact characterization of the crumpled globule ensemble relevant for dense topologically constrained polymer matter and DNA folding. Moreover, this result gives a stringent lower bound on the number of Hamiltonian walks on a simple cubic lattice. Additionally, we compute the exact number of crumpled curves with arbitrary endpoints, and the closed crumpled curves on a 4× 4× 4 cube.
A kill curve for Phanerozoic marine species
Raup, D. M.
1991-01-01
A kill curve for Phanerozoic species is developed from an analysis of the stratigraphic ranges of 17,621 genera, as compiled by Sepkoski. The kill curve shows that a typical species' risk of extinction varies greatly, with most time intervals being characterized by very low risk. The mean extinction rate of 0.25/m.y. is thus a mixture of long periods of negligible extinction and occasional pulses of much higher rate. Because the kill curve is merely a description of the fossil record, it does not speak directly to the causes of extinction. The kill curve may be useful, however, to li inverted question markmit choices of extinction mechanisms.
Ferguson curve model and morphological smoothing of ruled surfaces
Popov, Antony T.
2001-11-01
This work studies the generation of a ruled surface from scattered data, which can be obtained by a shape- from - X procedure or can be an experimental output. The ruled surface is generated by the so- called Ferguson Curve Model. This model is an interpolation technique based on parametric cubic polynomials, and thus guaranteeing continuity of the curvature in each point of the initial set. We show how morphological operations - esp. openings and closings can be used to obtain good smoothness of the surface in practice. An application to robot motion planning is presented.
Directory of Open Access Journals (Sweden)
irfan abbas
2017-01-01
Full Text Available At this time, the players Forex Trading generally still use the data exchange in the form of a Forex Trading figures from different sources. Thus they only receive or know the data rate of a Forex Trading prevailing at the time just so difficult to analyze or predict exchange rate movements future. Forex players usually use the indicators to enable them to analyze and memperdiksi future value. Indicator is a decision making tool. Trading forex is trading currency of a country, the other country's currency. Trading took place globally between the financial centers of the world with the involvement of the world's major banks as the major transaction. Trading Forex offers profitable investment type with a small capital and high profit, with relatively small capital can earn profits doubled. This is due to the forex trading systems exist leverage which the invested capital will be doubled if the predicted results of buy / sell is accurate, but Trading Forex having high risk level, but by knowing the right time to trade (buy or sell, the losses can be avoided. Traders who invest in the foreign exchange market is expected to have the ability to analyze the circumstances and situations in predicting the difference in currency exchange rates. Forex price movements that form the pattern (curve up and down greatly assist traders in making decisions. The movement of the curve used as an indicator in the decision to purchase (buy or sell (sell. This study compares (Comparation type algorithm kernel on Support Vector Machine (SVM to predict the movement of the curve in live time trading forex using the data GBPUSD, 1H. Results of research on the study of the results and discussion can be concluded that the Kernel Dot, Kernel Multiquaric, Kernel Neural inappropriately used for data is non-linear in the case of data forex to follow the pattern of trend curves, because curves generated curved linear (straight and then to type of kernel is the closest curve
Extremes in body mass index affect overall survival in women with cervical cancer.
Clark, Leslie H; Jackson, Amanda L; Soo, Adrianne E; Orrey, Danielle C; Gehrig, Paola A; Kim, Kenneth H
2016-06-01
To examine the effect of BMI on pathologic findings, cancer recurrence and survival in cervical cancer patients. A retrospective cohort study of cervical cancer patients treated from July 2000 to March 2013 was performed. BMI was calculated, and patients were classified by BMI. The primary outcome was overall survival (OS). Secondary outcomes included stage, histopathology, disease-specific survival (DSS) and recurrence free survival (RFS). Kaplan-Meier survival curves were generated and compared using Cox proportional hazard ratios. Of 632 eligible patients, 24 (4%) were underweight, 191 (30%) were normal weight, 417 (66%) were overweight/obese. There was no difference in age (p=0.91), stage at presentation (p=0.91), grade (p=0.46), or histology (p=0.76) between weight categories. There were fewer White patients in the underweight (54%) and overweight/obese (58%) groups compared to the normal weight (71%) group (p=0.04). After controlling for prognostic factors, underweight and overweight/obese patients had worse median RFS than normal weight patients (7.6 v 25.0months, p=0.01 and 20.3 v 25.0months, p=0.03). Underweight patients also had worse OS (10.4 v 28.4months, p=0.031) and DSS (13.8 v 28.4months, p=0.04) compared to normal weight patients. Overweight/obese patients had worse OS than normal weight patients (22.2 v 28.4months, p=0.03) and a trend toward worse DSS (21.9 v 28.4months, p=0.09). Both extremes of weight (underweight and overweight/obesity) were associated with worse survival in patients with cervical cancer. Optimizing weight in cervical cancer patients may improve outcomes in these patients. Copyright © 2016 Elsevier Inc. All rights reserved.
Single curved fiber sedimentation under gravity
Xiaoying Rong; Dewei Qi; Guowei He; Jun Yong Zhu; Tim Scott
2008-01-01
Dynamics of single curved fiber sedimentation under gravity are simulated by using the 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.
Comparison and evaluation of mathematical lactation curve ...
African Journals Online (AJOL)
Comparison and evaluation of mathematical lactation curve functions of Iranian primiparous Holsteins. ... South African Journal of Animal Science ... The suitability of seven mathematical models (with three, four and five parameters) for describing the 305-day milk yield lactation curve of Holstein cows, were examined in this ...
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.
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…
Mixture Modeling of Individual Learning Curves
Streeter, Matthew
2015-01-01
We show that student learning can be accurately modeled using a mixture of learning curves, each of which specifies error probability as a function of time. This approach generalizes Knowledge Tracing [7], which can be viewed as a mixture model in which the learning curves are step functions. We show that this generality yields order-of-magnitude…
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...
Modular curves, Arakelov theory, algorithmic applications
Bruin, Pieter Jan
2010-01-01
This thesis is about arithmetic, analytic and algorithmic aspects of modular curves and modular forms. The arithmetic and analytic aspects are linked by the viewpoint that modular curves are examples of arithmetic surfaces. Therefore, Arakelov theory (intersection theory on arithmetic surfaces)
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.
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...
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.
Trigonometric Characterization of Some Plane Curves
Indian Academy of Sciences (India)
IAS Admin
In this section, various types of families of algebraic curves are considered. Equations of these curves are written either in Cartesian coordinates (x, y) or in terms of plane polar coordinates (r, θ). In some cases, para- metric equations are also considered. 3.1 Astroid. In Cartesian coordinates, the equation of an astroid (Fig-.
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...
Meta-analysis of survival prediction with Palliative Performance Scale.
Downing, Michael; Lau, Francis; Lesperance, Mary; Karlson, Nicholas; Shaw, Jack; Kuziemsky, Craig; Bernard, Steve; Hanson, Laura; Olajide, Lola; Head, Barbara; Ritchie, Christine; Harrold, Joan; Casarett, David
2007-01-01
This paper aims to reconcile the use of Palliative Performance Scale (PPSv2) for survival prediction in palliative care through an international collaborative study by five research groups. The study involves an individual patient data meta-analysis on 1,808 patients from four original datasets to reanalyze their survival patterns by age, gender, cancer status, and initial PPS score. Our findings reveal a strong association between PPS and survival across the four datasets. The Kaplan-Meier survival curves show each PPS level as distinct, with a strong ordering effect in which higher PPS levels are associated with increased length of survival. Using a stratified Cox proportional hazard model to adjust for study differences, we found females lived significantly longer than males, with a further decrease in hazard for females not diagnosed with cancer. Further work is needed to refine the reporting of survival times/probabilities and to improve prediction accuracy with the inclusion of other variables in the models.
Pump function curve shape for a model lymphatic vessel.
Bertram, C D; Macaskill, C; Moore, J E
2016-07-01
The transport capacity of a contractile segment of lymphatic vessel is defined by its pump function curve relating mean flow-rate and adverse pressure difference. Numerous system characteristics affect curve shape and the magnitude of the generated flow-rates and pressures. Some cannot be varied experimentally, but their separate and interacting effects can be systematically revealed numerically. This paper explores variations in the rate of change of active tension and the form of the relation between active tension and muscle length, factors not known from experiment to functional precision. Whether the pump function curve bends toward or away from the origin depends partly on the curvature of the passive pressure-diameter relation near zero transmural pressure, but rather more on the form of the relation between active tension and muscle length. A pump function curve bending away from the origin defines a well-performing pump by maximum steady output power. This behaviour is favoured by a length/active-tension relationship which sustains tension at smaller lengths. Such a relationship also favours high peak mechanical efficiency, defined as output power divided by the input power obtained from the lymphangion diameter changes and active-tension time-course. The results highlight the need to pin down experimentally the form of the length/active-tension relationship. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.
Lof, Marjolein E.; Reed, Thomas E.; McNamara, John M.; Visser, Marcel E.
2012-01-01
Adaptation in dynamic environments depends on the grain, magnitude and predictability of ecological fluctuations experienced within and across generations. Phenotypic plasticity is a well-studied mechanism in this regard, yet the potentially complex effects of stochastic environmental variation on optimal mean trait values are often overlooked. Using an optimality model inspired by timing of reproduction in great tits, we show that temporal variation affects not only optimal reaction norm slope, but also elevation. With increased environmental variation and an asymmetric relationship between fitness and breeding date, optimal timing shifts away from the side of the fitness curve with the steepest decline. In a relatively constant environment, the timing of the birds is matched with the seasonal food peak, but they become adaptively mismatched in environments with temporal variation in temperature whenever the fitness curve is asymmetric. Various processes affecting the survival of offspring and parents influence this asymmetry, which collectively determine the ‘safest’ strategy, i.e. whether females should breed before, on, or after the food peak in a variable environment. As climate change might affect the (co)variance of environmental variables as well as their averages, risk aversion may influence how species should shift their seasonal timing in a warming world. PMID:22628472
A digital algorithm for characteristic film curves
Buckner, J.; Cash, T.; Craven, P.; Edwards, T.
1975-01-01
The task of establishing a film calibration scheme for magnitude studies of Skylab photographic images of Comet Kohoutek is examined. Since the data are recorded in terms of film density and have to be used in terms of exposure, the conversion from density to exposure is critical. In this film calibration scheme, the hardware deals with the data sources, recording medium, and data conversion to a computer compatible program, whereas the software deals with signal to noise enhancement, stepwedge calibration curve and leads to modeling of the film characteristic curves. A mathematical model of the characteristic curve is obtained using a modified version of Efroymson's (1960) stepwise multiple linear regression algorithm, which gives log exposure as a function of density. The difference in the calibration curves from pre- and postflight exposures is well accounted for in the model as a result of sensitive statistical tests. The characteristic curve modeling program requires about 4K of core and is executed in about 3 min.
N-Covers of hyperelliptic curves
Bruin, N.; Flynn, E. V.
2003-05-01
For a hyperelliptic curve {ax C} of genus g with a divisor class of order n = g + 1, we shall consider an associated covering collection of curves {ax D}_delta, each of genus g(2) . We describe, up to isogeny, the Jacobian of each {ax D}_delta via a map from {ax D}_delta to {ax C}, and two independent maps from {ax D}_delta to a curve of genus g(g-1)/2. For some curves, this allows covering techniques that depend on arithmetic data of number fields of smaller degree than standard 2-coverings; we illustrate this by using 3-coverings to find all {Bbb Q}-rational points on a curve of genus 2 for which 2-covering techniques would be impractical.
"Universal" Recession Curves and their Geomorphological Roots
Marani, M.; Biswal, B.
2011-12-01
The basic structural organization of channel networks, and of the connected hillslopes, have been shown to be intimately linked to basin responses to rainfall events, leading to geomorphological theories of the hydrologic response. Here, We identify a previously undetected link between the river network morphology and key recession curves properties. We show that the power-law exponent of -dQ/dt vs. Q curves is related to the power-law exponent of N(l) vs. G(l) curves (which we show to be connected to Hack's law), where l is the downstream distance from the channel heads, N(l) is the number of channel reaches exactly located at a distance l from their channel head, and G(l) is the total length of the network located at a distance greater or equal to l from channel heads. We then generalize the power-law expressions of recession curves, to identify "universal" curves, independent of the initial moisture conditions and of basin area, by making the -dQ/dt vs. Q curve non-dimensional using an index discharge representative of initial moisture conditions. We subsequently rescale the geomorphic recession curve, N(l) vs. G(l), producing a collapse of the geomorphic recession curves constructed from the DTM's of 67 US study basins. Finally, by use of the specific discharge u = Q/A, we link the two previous results and define the specific recession curves, whose collapse across basins within homogeneous geographical areas lends further, decisive, support to the notion that the statistical properties of observational recession curves bear the signature of the geomorphological structure of the networks producing them.
Multinationals and plant survival
DEFF Research Database (Denmark)
Bandick, Roger
2010-01-01
The aim of this paper is twofold: first, to investigate how different ownership structures affect plant survival, and second, to analyze how the presence of foreign multinational enterprises (MNEs) affects domestic plants’ survival. Using a unique and detailed data set on the Swedish manufacturing...... sector, I am able to separate plants into those owned by foreign MNEs, domestic MNEs, exporting non-MNEs, and purely domestic firms. In line with previous findings, the result, when conditioned on other factors affecting survival, shows that foreign MNE plants have lower survival rates than non......-MNE plants. However, separating the non-MNEs into exporters and non-exporters, the result shows that foreign MNE plants have higher survival rates than non-exporting non-MNEs, while the survival rates of foreign MNE plants and exporting non-MNE plants do not seem to differ. Moreover, the simple non...
Tüzün, Nedim; Op de Beeck, Lin; Brans, Kristien I; Janssens, Lizanne; Stoks, Robby
2017-12-01
The rapidly increasing rate of urbanization has a major impact on the ecology and evolution of species. While increased temperatures are a key aspect of urbanization ("urban heat islands"), we have very limited knowledge whether this generates differentiation in thermal responses between rural and urban populations. In a common garden experiment, we compared the thermal performance curves (TPCs) for growth rate and mortality in larvae of the damselfly Coenagrion puella from three urban and three rural populations. TPCs for growth rate shifted vertically, consistent with the faster-slower theoretical model whereby the cold-adapted rural larvae grew faster than the warm-adapted urban larvae across temperatures. In line with costs of rapid growth, rural larvae showed lower survival than urban larvae across temperatures. The relatively lower temperatures hence expected shorter growing seasons in rural populations compared to the populations in the urban heat islands likely impose stronger time constraints to reach a certain developmental stage before winter, thereby selecting for faster growth rates. In addition, higher predation rates at higher temperature may have contributed to the growth rate differences between urban and rural ponds. A faster-slower differentiation in TPCs may be a widespread pattern along the urbanization gradient. The observed microgeographic differentiation in TPCs supports the view that urbanization may drive life-history evolution. Moreover, because of the urban heat island effect, urban environments have the potential to aid in developing predictions on the impact of climate change on rural populations.
Hyperorthogonal well-folded Hilbert curves
Directory of Open Access Journals (Sweden)
Arie Bos
2016-03-01
Full Text Available R-trees can be used to store and query sets of point data in two or more dimensions. An easy way to construct and maintain R-trees for two-dimensional points, due to Kamel and Faloutsos, is to keep the points in the order in which they appear along the Hilbert curve. The R-tree will then store bounding boxes of points along contiguous sections of the curve, and the efficiency of the R-tree depends on the size of the bounding boxes---smaller is better. Since there are many different ways to generalize the Hilbert curve to higher dimensions, this raises the question which generalization results in the smallest bounding boxes. Familiar methods, such as the one by Butz, can result in curve sections whose bounding boxes are a factor $\\Omega(2^{d/2}$ larger than the volume traversed by that section of the curve. Most of the volume bounded by such bounding boxes would not contain any data points. In this paper we present a new way of generalizing Hilbert's curve to higher dimensions, which results in much tighter bounding boxes: they have at most 4 times the volume of the part of the curve covered, independent of the number of dimensions. Moreover, we prove that a factor 4 is asymptotically optimal.
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...... administrative micro data we find that the elasticity of the wage-setting curve is particularly high for young workers and workers with an university degree, while it is low for older workers and workers with a vocational degree. The wage and employment effects of migration are moderate: a 1 percent increase...
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.
Magnetization curve modelling of soft magnetic alloys
Energy Technology Data Exchange (ETDEWEB)
Meszaros, I, E-mail: meszaros@eik.bme.hu [Department of Materials Science and Engineering, Budapest University of Technology and Economics, Bertalan L. street 7., Budapest, H-1111 (Hungary)
2011-01-01
In this paper we present an application of the so called hyperbolic model of magnetization. The model was modified and it was applied for nine different soft magnetic alloys. The tested samples were electro-technical steels (FeSi alloys) and a permalloy (FeNi alloy) with strongly different magnetic properties. Among them there are top, medium and definitely poor quality soft magnetic materials as well. Their minor hysteresis loops and normal magnetization curves were measured by alternating current measurement. The hyperbolic model of magnetization was applied for the experimental normal magnetization curves. It was proved that the applied model is excellent for describing mathematically the experimental magnetization curves.
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.
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.
Estimating the Area under a Receiver Operating Characteristic Curve For Repeated Measures Design
Directory of Open Access Journals (Sweden)
Honghu Liu
2003-07-01
Full Text Available The receiver operating characteristic (ROC curve is widely used for diagnosing as well as for judging the discrimination ability of different statistical models. Although theories about ROC curves have been established and computation methods and computer software are available for cross-sectional design, limited research for estimating ROC curves and their summary statistics has been done for repeated measure designs, which are useful in many applications, such as biological, medical and health services research. Furthermore, there is no published statistical software available that can generate ROC curves and calculate summary statistics of the area under a ROC curve for data from a repeated measures design. Using generalized linear mixed model (GLMM, we estimate the predicted probabilities of the positivity of a disease or condition, and the estimated probability is then used as a bio-marker for constructing the ROC curve and computing the area under the curve. The area under a ROC curve is calculated using the Wilcoxon non-parametric approach by comparing the predicted probability of all discordant pairs of observations. The ROC curve is constructed by plotting a series of pairs of true positive rate (sensitivity and false positive rate (1- specificity calculated from varying cuts of positivity escalated by increments of 0.005 in predicted probability. The computation software is written in SAS/IML/MACRO v8 and can be executed in any computer that has a working SAS v8 system with SAS/IML/MACRO.
Huang, Steven Y; Odisio, Bruno C; Sabir, Sharjeel H; Ensor, Joe E; Niekamp, Andrew S; Huynh, Tam T; Kroll, Michael; Gupta, Sanjay
2017-07-01
Our purpose was to develop a predictive model for short-term survival (i.e. modeling was used to assess variables associated with 6 month survival following filter placement in patients with VTE and solid malignancy. Significant variables were used to generate a predictive model. 397 patients with solid malignancy received a filter during the study period. Three variables were associated with 6 month survival: (1) serum albumin [hazard ratio (HR) 0.496, P predictive model to estimate 6 month survival with an area under the receiver operating characteristic curve of 0.815, sensitivity of 0.782, and specificity of 0.715. Six month survival in patients with VTE and solid malignancy requiring filter placement can be predicted from three patient variables. Our predictive model could be used to help physicians decide whether a permanent or retrievable filter may be more appropriate as well as to assess the risks and benefits for filter retrieval within the context of survival longevity in patients with cancer.
Nestling Weight and Survival in Individual Great Tits (Parus major)
Tinbergen, J.M.; Boerlijst, M.C.
1990-01-01
(1) The aim of this paper is to estimate the shape of the curve relating first year survival to nestling weight in individual great tits (Parus major) and to study the causality of this relationship. (2) Data were collected in a mainland and an island population. Nestlings were weighed and sexed in
Classification of ASKAP Vast Radio Light Curves
Rebbapragada, Umaa; Lo, Kitty; Wagstaff, Kiri L.; Reed, Colorado; Murphy, Tara; Thompson, David R.
2012-01-01
The VAST survey is a wide-field survey that observes with unprecedented instrument sensitivity (0.5 mJy or lower) and repeat cadence (a goal of 5 seconds) that will enable novel scientific discoveries related to known and unknown classes of radio transients and variables. Given the unprecedented observing characteristics of VAST, it is important to estimate source classification performance, and determine best practices prior to the launch of ASKAP's BETA in 2012. The goal of this study is to identify light curve characterization and classification algorithms that are best suited for archival VAST light curve classification. We perform our experiments on light curve simulations of eight source types and achieve best case performance of approximately 90% accuracy. We note that classification performance is most influenced by light curve characterization rather than classifier algorithm.
Aluminized fiberglass insulation conforms to curved surfaces
1966-01-01
Layers of fiber glass with outer reflective films of vacuum-deposited aluminum or other reflective metal, provide thermal insulation which conforms to curved surfaces. This insulation has good potential for cryogenic systems.
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...
Modeling Type IIn Supernova Light Curves
De La Rosa, Janie; Roming, Peter; Fryer, Chris
2016-01-01
We present near-by Type IIn supernovae observed with Swift's Ultraviolet/Optical Telescope (UVOT). Based on the diversity of optical light curve properties, this Type II subclass is commonly referred to as heterogeneous. At the time of discovery, our IIn sample is ~ 2 magnitudes brighter at ultraviolet wavelengths than at optical wavelengths, and ultraviolet brightness decays faster than the optical brightness. We use a semi-analytical supernova (SN) model to better understand our IIn observations, and focus on matching specific observed light curves features, i.e peak luminosity and decay rate. The SN models are used to study the effects of initial SN conditions on early light curves, and to show the extent of the "uniqueness" problem in SN light curves. We gratefully acknowledge the contributions from members of the Swift UVOT team, the NASA astrophysics archival data analysis program, and the NASA Swift guest investigator program.
Projective curves, hyperplane sections and associated webs
Directory of Open Access Journals (Sweden)
Edoardo Ballico
2014-10-01
Full Text Available An integral and non-degenerate curve $C\\subset \\mathbb {P}^r$ is said to be ordinary (Gruson, Hantout and Lehmann if if the general hyperplane section $H\\cap C$ of $H$ is of maximal rank in $H$. Let $g'(r,d$ be the maximal integer such that for every $g\\in \\{0,\\dots ,g'(r,d\\}$ there is a smooth ordinary curve $C\\subset \\mathbb {P}^r$ with degree $d$ and genus $g$. Here we discuss the relevance of old papers to get a lower bound for $g'(r,d$. We prove that arithmetically Gorenstein curves $C \\subset \\mathbb {P}^r$ are ordinary only if either $r=2$ or $d =r+1$ and $\\omega _C \\cong \\mathcal {O}_C$. We prove that general low genus curves are ordinary.
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...
KAIT Fermi AGN Light-Curve Reservoir
National Aeronautics and Space Administration — This web page shows the light curves of a total of 163 AGNs that are monitored by KAIT with average cadence of 3 days. These are unfiltered observations; in...
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
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
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
Survival in common cancers defined by risk and survival of family members
Directory of Open Access Journals (Sweden)
Jianguang Ji
2011-10-01
Full Text Available Studies on survival between familial and sporadic cancers have been inconclusive and only recent data on a limited number of cancers are available on the concordance of survival between family members. In this review, we address these questions by evaluating the published and unpublished data from the nation-wide Swedish Family-Cancer Database and a total of 13 cancer sites were assessed. Using sporadic cancer as reference, HRs were close to 1.0 for most of the familial cancers in both the offspring and parental generations, which suggested that survival in patients with familial and sporadic cancers was equal, with an exception for ovarian cancer with a worse prognosis. Compared to offspring whose parents had a poor survival, those with a good parental survival had a decreased risk of death for most cancers and HR was significantly decreased for cancers in the breast, prostate, bladder, and kidney. For colorectal and nervous system cancers, favorable survival between the generations showed a borderline significance. These data are consistent in showing that both good and poor survival in certain cancers aggregate in families. Genetic factors are likely to contribute to the results. These observations call for intensified efforts to consider heritability in survival as one mechanism regulating prognosis in cancer patients.
Evolution of the extinction curves in galaxies
Asano, Ryosuke S.; Takeuchi, Tsutomu T.; Hirashita, Hiroyuki; Nozawa, Takaya
2014-01-01
We investigate the evolution of extinction curves in galaxies based on our evolution model of grain size distribution. In this model, we considered various processes: dust formation by SNe II and AGB stars, dust destruction by SN shocks in the ISM, metal accretion onto the surface of grains (referred to as grain growth), shattering and coagulation. We find that the extinction curve is flat in the earliest stage of galaxy evolution. As the galaxy is enriched with dust, shattering becomes effec...
Harmonic algebraic curves and noncrossing partitions
Martin, Jeremy; Savitt, David; Singer, Ted
2005-01-01
Motivated by Gauss's first proof of the Fundamental Theorem of Algebra, we study the topology of harmonic algebraic curves. By the maximum principle, a harmonic curve has no bounded components; its topology is determined by the combinatorial data of a noncrossing matching. Similarly, every complex polynomial gives rise to a related combinatorial object that we call a basketball, consisting of a pair of noncrossing matchings satisfying one additional constraint. We prove that every noncrossing...
Gain Estimation of Doubly Curved Reflector Antenna
Directory of Open Access Journals (Sweden)
V. Schejbal
2008-09-01
Full Text Available A simple formula of approximate gain estimation is verified for the doubly curved reflector antenna. Numerical simulations using physical optics and experimental results of the shaped-beam doubly curved reflector antenna are compared with the simple approximation of gain. That approximation could be very valuable for system engineers to accurately estimate antenna gain and coverage pattern and perform EMC calculations (estimations of interferences and susceptibilities even for the operation and out of operation frequency bands of shapedbeam antenna.
Elucidation of non-parallel EIA curves
François-Gérard, C.; Gérard, Paul; Rentier, Bernard
1988-01-01
Quantitative determinations by EIA can be only obtained by reverse regression when linear portions of sample and standard curves are parallel. However, analysis of complex biological fluids often yields sigmoid curves displaying lower slopes, thus invalidating any quantitative interpretation. We hypothesized that this phenomenon was due to a competition effect between the target (for example an antigen) and related molecules for the binding sites (for example a capture antibody) immobilized o...
Mental Effort and Safety in Curved Approaches
Entzinger, Jorg Onno; Uemura, Tsuneharu; Suzuki, Shinji
2014-01-01
Curved approach procedures are implemented around the world. Although typically flown by the autopilot, human pilots need the situational awareness and skills to take over control in rare-event cases to ensure flight safety. We try to understand the pilot’s cognitive models and differences in required (mental) effort between conventional straight-in approaches and curved approaches. We developed various methods to visualize pilots’ control efforts during manual flight, show their capabilities...
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...
A Novel Construction Method for n-Dimensional Hilbert Space-Filling Curves
Chen, Chih-Sheng; Lin, Shen-Yi; Fan, Min-Hsuan; Huang, Chua-Huang
We develop a novel construction method forn-dimensional Hilbert space-filling curves. The construction method includes four steps: block allocation, Gray permutation, coordinate transformation and recursive construction. We use the tensor product theory to formulate the method. Ann-dimensional Hilbert space-filling curve of 2r elements on each dimension is specified as a permutation which rearranges 2rn data elements stored in the row major order as in C language or the column major order as in FORTRAN language to the order of traversing ann-dimensional Hilbert space-filling curve. The tensor product formulation ofn-dimensional Hilbert space-filling curves uses stride permutation, reverse permutation, and Gray permutation. We present both recursive and iterative tensor product formulas ofn-dimensional Hilbert space-filling curves. The tensor product formulas are directly translated into computer programs which can be used in various applications. The process of program generation is explained in the paper.
Energy Technology Data Exchange (ETDEWEB)
Pickles, Martin D. [Centre for Magnetic Resonance Investigations, Division of Cancer, Postgraduate Medical School, University of Hull, Hull Royal Infirmary, Anlaby Road, Hull, HU3 2JZ (United Kingdom)], E-mail: m.pickles@hull.ac.uk; Manton, David J. [Centre for Magnetic Resonance Investigations, Division of Cancer, Postgraduate Medical School, University of Hull, Hull Royal Infirmary, Anlaby Road, Hull, HU3 2JZ (United Kingdom)], E-mail: d.j.manton@hull.ac.uk; Lowry, Martin [Centre for Magnetic Resonance Investigations, Division of Cancer, Postgraduate Medical School, University of Hull, Hull Royal Infirmary, Anlaby Road, Hull, HU3 2JZ (United Kingdom)], E-mail: m.lowry@hull.ac.uk; Turnbull, Lindsay W. [Centre for Magnetic Resonance Investigations, Division of Cancer, Postgraduate Medical School, University of Hull, Hull Royal Infirmary, Anlaby Road, Hull, HU3 2JZ (United Kingdom)], E-mail: l.w.turnbull@hull.ac.uk
2009-09-15
The purpose of this study was to investigate whether dynamic contrast enhanced MRI (DCE-MRI) data, both pharmacokinetic and empirical, can predict, prior to neoadjuvant chemotherapy, which patients are likely to have a shorter disease free survival (DFS) and overall survival (OS) interval following surgery. Traditional prognostic parameters were also included in the survival analysis. Consequently, a comparison of the prognostic value could be made between all the parameters studied. MR examinations were conducted on a 1.5 T system in 68 patients prior to the initiation of neoadjuvant chemotherapy. DCE-MRI consisted of a fast spoiled gradient echo sequence acquired over 35 phases with a mean temporal resolution of 11.3 s. Both pharmacokinetic and empirical parameters were derived from the DCE-MRI data. Kaplan-Meier survival plots were generated for each parameter and group comparisons were made utilising logrank tests. The results from the 54 patients entered into the univariate survival analysis demonstrated that traditional prognostic parameters (tumour grade, hormonal status and size), empirical parameters (maximum enhancement index, enhancement index at 30 s, area under the curve and initial slope) and adjuvant therapies demonstrated significant differences in survival intervals. Further multivariate Cox regression survival analysis revealed that empirical enhancement parameters contributed the greatest prediction of both DFS and OS in the resulting models. In conclusion, this study has demonstrated that in patients who exhibit high levels of perfusion and vessel permeability pre-treatment, evidenced by elevated empirical DCE-MRI parameters, a significantly lower disease free survival and overall survival can be expected.
Expression profiles of loneliness-associated genes for survival prediction in cancer patients.
You, Liang-Fu; Yeh, Jia-Rong; Su, Mu-Chun
2014-01-01
Influence of loneliness on human survival has been established epidemiologically, but genomic research remains undeveloped. We identified 34 loneliness-associated genes which were statistically significant for high- lonely and low-lonely individuals. With the univariate Cox proportional hazards regression model, we obtained corresponding regression coefficients for loneliness-associated genes fo individual cancer patients. Furthermore, risk scores could be generated with the combination of gene expression level multiplied by corresponding regression coefficients of loneliness-associated genes. We verified that high-risk score cancer patients had shorter mean survival time than their low-risk score counterparts. Then we validated the loneliness-associated gene signature in three independent brain cancer cohorts with Kaplan-Meier survival curves (n=77, 85 and 191), significantly separable by log-rank test with hazard ratios (HR) >1 and p-values loneliness-associated gene signature in bone cancer (HR=5.10, p-value=4.69e-3), lung cancer (HR=2.86, p-value=4.71e-5), ovarian cancer (HR=1.97, p-value=3.11e-5), and leukemia (HR=2.06, p-value=1.79e-4) cohorts. The last lymphoma cohort proved to have an HR=3.50, p-value=1.15e-7. Loneliness- associated genes had good survival prediction for cancer patients, especially bone cancer patients. Our study provided the first indication that expression of loneliness-associated genes are related to survival time of cancer patients.
Exploratory analysis of ERCC2 DNA methylation in survival among pediatric medulloblastoma patients.
Banfield, Emilyn; Brown, Austin L; Peckham, Erin C; Rednam, Surya P; Murray, Jeffrey; Okcu, M Fatih; Mitchell, Laura E; Chintagumpala, Murali M; Lau, Ching C; Scheurer, Michael E; Lupo, Philip J
2016-10-01
Medulloblastoma is the most frequent malignant pediatric brain tumor. While survival rates have improved due to multimodal treatment including cisplatin-based chemotherapy, there are few prognostic factors for adverse treatment outcomes. Notably, genes involved in the nucleotide excision repair pathway, including ERCC2, have been implicated in cisplatin sensitivity in other cancers. Therefore, this study evaluated the role of ERCC2 DNA methylation profiles on pediatric medulloblastoma survival. The study population included 71 medulloblastoma patients (age DNA methylation profiles were generated from peripheral blood samples using the Illumina Infinium Human Methylation 450 Beadchip. Sixteen ERCC2-associated CpG sites were evaluated in this analysis. Multivariable regression models were used to determine the adjusted association between DNA methylation and survival. Cox regression and Kaplan-Meier curves were used to compare 5-year overall survival between hyper- and hypo-methylation at each CpG site. In total, 12.7% (n=9) of the patient population died within five years of diagnosis. In our population, methylation of the cg02257300 probe (Hazard Ratio=9.33; 95% Confidence Interval: 1.17-74.64) was associated with death (log-rank p=0.01). This association remained suggestive after correcting for multiple comparisons (FDR pDNA methylation within the promoter region of the ERCC2 gene may be associated with survival in pediatric medulloblastoma. If confirmed in future studies, this information may lead to improved risk stratification or promote the development of novel, targeted therapeutics. Copyright © 2016 Elsevier Ltd. All rights reserved.
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.
Tolstov, Alexey; Nomoto, Ken'ichi; Tominaga, Nozomu; Ishigaki, Miho N.; Blinnikov, Sergey; Suzuki, Tomoharu
We study the multicolor light curves for a number of metal-free core-collapse supernova (SN) models (25-100 ⊙ ) to determine the indicators for the detection and identification of first generation SNe. We use mixing-fallback supernova explosion models that explain the observed abundance patterns of metal-poor stars. Numerical calculations of the multicolor light curves are performed using the multigroup radiation hydrodynamic code STELLA. The calculated light curves of metal-free SNe are compared with solar-metallicity models and observed SNe. We conclude that the multicolor light curves could be used to identify first-generation SNe in current (Subaru/HSC) and future transient surveys (LSST, James Webb Space Telescope). They are also suitable for identifying low-metallicity SNe in the nearby universe (PTF, Pan-STARRS, Gaia).
The average receiver operating characteristic curve in multireader multicase imaging studies
Samuelson, F W
2014-01-01
Objective: In multireader, multicase (MRMC) receiver operating characteristic (ROC) studies for evaluating medical imaging systems, the area under the ROC curve (AUC) is often used as a summary metric. Owing to the limitations of AUC, plotting the average ROC curve to accompany the rigorous statistical inference on AUC is recommended. The objective of this article is to investigate methods for generating the average ROC curve from ROC curves of individual readers. Methods: We present both a non-parametric method and a parametric method for averaging ROC curves that produce a ROC curve, the area under which is equal to the average AUC of individual readers (a property we call area preserving). We use hypothetical examples, simulated data and a real-world imaging data set to illustrate these methods and their properties. Results: We show that our proposed methods are area preserving. We also show that the method of averaging the ROC parameters, either the conventional bi-normal parameters (a, b) or the proper bi-normal parameters (c, da), is generally not area preserving and may produce a ROC curve that is intuitively not an average of multiple curves. Conclusion: Our proposed methods are useful for making plots of average ROC curves in MRMC studies as a companion to the rigorous statistical inference on the AUC end point. The software implementing these methods is freely available from the authors. Advances in knowledge: Methods for generating the average ROC curve in MRMC ROC studies are formally investigated. The area-preserving criterion we defined is useful to evaluate such methods. PMID:24884728
Predicting the Survival of Gastric Cancer Patients Using Artificial and Bayesian Neural Networks
Korhani Kangi, Azam; Bahrampour, Abbas
2018-02-26
Introduction and purpose: In recent years the use of neural networks without any premises for investigation of prognosis in analyzing survival data has increased. Artificial neural networks (ANN) use small processors with a continuous network to solve problems inspired by the human brain. Bayesian neural networks (BNN) constitute a neural-based approach to modeling and non-linearization of complex issues using special algorithms and statistical methods. Gastric cancer incidence is the first and third ranking for men and women in Iran, respectively. The aim of the present study was to assess the value of an artificial neural network and a Bayesian neural network for modeling and predicting of probability of gastric cancer patient death. Materials and Methods: In this study, we used information on 339 patients aged from 20 to 90 years old with positive gastric cancer, referred to Afzalipoor and Shahid Bahonar Hospitals in Kerman City from 2001 to 2015. The three layers perceptron neural network (ANN) and the Bayesian neural network (BNN) were used for predicting the probability of mortality using the available data. To investigate differences between the models, sensitivity, specificity, accuracy and the area under receiver operating characteristic curves (AUROCs) were generated. Results: In this study, the sensitivity and specificity of the artificial neural network and Bayesian neural network models were 0.882, 0.903 and 0.954, 0.909, respectively. Prediction accuracy and the area under curve ROC for the two models were 0.891, 0.944 and 0.935, 0.961. The age at diagnosis of gastric cancer was most important for predicting survival, followed by tumor grade, morphology, gender, smoking history, opium consumption, receiving chemotherapy, presence of metastasis, tumor stage, receiving radiotherapy, and being resident in a village. Conclusion: The findings of the present study indicated that the Bayesian neural network is preferable to an artificial neural network for
Columbia Crew Survival Investigation Report
2009-01-01
NASA commissioned the Columbia Accident Investigation Board (CAIB) to conduct a thorough review of both the technical and the organizational causes of the loss of the Space Shuttle Columbia and her crew on February 1, 2003. The accident investigation that followed determined that a large piece of insulating foam from Columbia s external tank (ET) had come off during ascent and struck the leading edge of the left wing, causing critical damage. The damage was undetected during the mission. The CAIB's findings and recommendations were published in 2003 and are available on the web at http://caib.nasa.gov/. NASA responded to the CAIB findings and recommendations with the Space Shuttle Return to Flight Implementation Plan. Significant enhancements were made to NASA's organizational structure, technical rigor, and understanding of the flight environment. The ET was redesigned to reduce foam shedding and eliminate critical debris. In 2005, NASA succeeded in returning the space shuttle to flight. In 2010, the space shuttle will complete its mission of assembling the International Space Station and will be retired to make way for the next generation of human space flight vehicles: the Constellation Program. The Space Shuttle Program recognized the importance of capturing the lessons learned from the loss of Columbia and her crew to benefit future human exploration, particularly future vehicle design. The program commissioned the Spacecraft Crew Survival Integrated Investigation Team (SCSIIT). The SCSIIT was asked to perform a comprehensive analysis of the accident, focusing on factors and events affecting crew survival, and to develop recommendations for improving crew survival for all future human space flight vehicles. To do this, the SCSIIT investigated all elements of crew survival, including the design features, equipment, training, and procedures intended to protect the crew. This report documents the SCSIIT findings, conclusions, and recommendations.
Stronger Misdirection in Curved than in Straight Motion
Otero-Millan, Jorge; Macknik, Stephen L.; Robbins, Apollo; Martinez-Conde, Susana
2011-01-01
Illusions developed by magicians are a rich and largely untapped source of insight into perception and cognition. Here we show that curved motion, as employed by the magician in a classic sleight of hand trick, generates stronger misdirection than rectilinear motion, and that this difference can be explained by the differential engagement of the smooth pursuit and the saccadic oculomotor systems. This research exemplifies how the magician’s intuitive understanding of the spectator’s mindset can surpass that of the cognitive scientist in specific instances, and that observation-based behavioral insights developed by magicians are worthy of quantitative investigation in the neuroscience laboratory. PMID:22125518
Distribution of some sequences of points on elliptic curves
DEFF Research Database (Denmark)
Lange, Tanja; Shparlinski, Igor
2007-01-01
We estimate character sums over points on elliptic curves over a finite field of q elements. Pseudorandom sequences can be constructed by taking linear combinations with small coefficients (for example, from the set {−1, 0, 1}) of a fixed vector of points, which forms the seed of the generator. We...... consider several particular cases of this general approach which are of special practical interest and have occurred in the literature. For each of them we show that the resulting sequence has good uniformity of distribution properties....
Stronger misdirection in curved than in straight motion
Directory of Open Access Journals (Sweden)
Jorge eOtero-Millan
2011-11-01
Full Text Available Illusions developed by magicians are a rich and largely untapped source of insight into perception and cognition. Here we show that curved motion, as employed by the magician in a classic sleight of hand trick, generates stronger misdirection than rectilinear motion, and that this difference can be explained by the differential engagement of the smooth pursuit and the saccadic oculomotor systems. This research moreover exemplifies how the magician’s intuitive understanding of the spectator’s mindset can surpass that of the cognitive scientist in specific instances, and that observation-based behavioral insights developed by magicians are worthy of quantitative investigation in the neuroscience laboratory.
Classification of conics and Cassini curves in Minkowski space-time plane
Directory of Open Access Journals (Sweden)
Emad N. Shonoda
2016-04-01
Full Text Available In this paper we use the Apollonius definition of conics to generate algebraic curves in the Minkowski space-time plane M2, which turn out to be different from classical conic sections. We extend and classify this sort of “M-conics”. We discuss the cases of the singularity points of these M-conics, coming from the transition from timelike world to spacelike world through the lightlike one. Finally, we translate the classical concept of Cassini curves with two foci and that of (multifocal Cassini curves to Minkowski planes M2.
A Model for Improving the Learning Curves of Artificial Neural Networks.
Directory of Open Access Journals (Sweden)
Roberto L S Monteiro
Full Text Available In this article, the performance of a hybrid artificial neural network (i.e. scale-free and small-world was analyzed and its learning curve compared to three other topologies: random, scale-free and small-world, as well as to the chemotaxis neural network of the nematode Caenorhabditis Elegans. One hundred equivalent networks (same number of vertices and average degree for each topology were generated and each was trained for one thousand epochs. After comparing the mean learning curves of each network topology with the C. elegans neural network, we found that the networks that exhibited preferential attachment exhibited the best learning curves.
DEFF Research Database (Denmark)
Acheampong, George; Narteh, Bedman; Rand, John
2017-01-01
Poultry farming has been touted as one of the major ways by which poverty can be reduced in low-income economies like Ghana. Yet, anecdotally there is a high failure rate among these poultry farms. This current study seeks to understand the relationship between network ties and survival chances...... of small commercial poultry farms (SCPFs). We utilize data from a 2-year network survey of SCPFs in rural Ghana. The survival of these poultry farms are modelled using a lagged probit model of farms that persisted from 2014 into 2015. We find that network ties are important to the survival chances...... but this probability reduces as the number of industry ties increases but moderation with dynamic capability of the firm reverses this trend. Our findings show that not all network ties aid survival and therefore small commercial poultry farmers need to be circumspect in the network ties they cultivate and develop....
Special Bertrand Curves in 4D Galilean Space
Directory of Open Access Journals (Sweden)
Handan Öztekin
2014-01-01
Full Text Available The generalization of Bertrand curves in Galilean 4-space is introduced and the characterization of the generalized Bertrand curves is obtained. Furthermore, it is proved that no special curve is a classical Bertrand curve in Galilean 4-space such that the notion of classical Bertrand curve is definite only in three-dimensional spaces.
Agilan, V.; Umamahesh, N. V.
2016-10-01
Storm water management and other engineering design applications are primarily based on rainfall Intensity-Duration-Frequency (IDF) curves and the existing IDF curves are based on the concept of stationary Extreme Value Theory (EVT). However, during the last few decades, global climate change is intensifying the extreme precipitation events and creating a non-stationary component in the extreme rainfall time series. Subsequently, in recent years, advancements in the EVT helped the researchers to propose a method for developing non-stationary rainfall IDF curve by modelling trend present in the observed extreme rainfall series using covariate. But, is it capable of encompassing future rainfall changes? Towards answering this question, the Hyderabad city, India non-stationary rainfall IDF curves are compared with the IDF curves of two future time periods (2015-2056 and 2057-2098). Using 24 Global Climate Models' (GCMs') simulations and 'K' Nearest Neighbor (KNN) weather generator based downscaling method, the IDF curves are developed for two future time periods and they are compared with covariate based non-stationary rainfall IDF curves of the Hyderabad city. The results of this study indicate that the return of period of an extreme rainfall of the Hyderabad city is reducing. In addition, it is noted that the non-stationary IDF curve developed by modelling trend in the observed extreme rainfall with covariate is an appropriate choice for designing the Hyderabad city infrastructure under climate change.
Hidayat, I.
2016-09-01
Power projects in the geothermal field has a long span of about 30 years. The power supply should be maintained at a certain value across a range of time. A geothermal field, however, has the characteristics of natural production decline with time. In a geothermal field, development of decline curve model of steam production is important for forecasting production decline in the future. This study was developed using decline curve by production data along 3 years liquid-dominated geothermal reservoir in Ulubelu field. Decline curve in geothermal field based on decline curve in petroleum industry. The decline curve was correlated by reservoir management in geothermal. The purposes of this study to get best match model decline curve and forecasting production in the future. Based on decline curve analysis by production data in Ulubelu field, the result model decline curve is exponential model. From the model, we can get the value of decline rate in the field is 9.4 %/year. Then, the formula of forecasting steam flow used exponent decline to forecast in the future. By using separated system cycle in Ulubelu field, the minimal steam flowrate towards turbine was 502018.4 ton/month. Based on formula of forecasting production and minimal steam flowrate, we can get the time make up wells to maintain steam supply for stability in generator power capacity.
Escherichia coli survival in waters: temperature dependence.
Blaustein, R A; Pachepsky, Y; Hill, R L; Shelton, D R; Whelan, G
2013-02-01
Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q₁₀ model. This suggestion was made 34 years ago based on 20 survival curves taken from published literature, but has not been revisited since then. The objective of this study was to re-evaluate the accuracy of the Q₁₀ equation, utilizing data accumulated since 1978. We assembled a database of 450 E. coli survival datasets from 70 peer-reviewed papers. We then focused on the 170 curves taken from experiments that were performed in the laboratory under dark conditions to exclude the effects of sunlight and other field factors that could cause additional variability in results. All datasets were tabulated dependencies "log concentration vs. time." There were three major patterns of inactivation: about half of the datasets had a section of fast log-linear inactivation followed by a section of slow log-linear inactivation; about a quarter of the datasets had a lag period followed by log-linear inactivation; and the remaining quarter were approximately linear throughout. First-order inactivation rate constants were calculated from the linear sections of all survival curves and the data grouped by water sources, including waters of agricultural origin, pristine water sources, groundwater and wells, lakes and reservoirs, rivers and streams, estuaries and seawater, and wastewater. Dependency of E. coli inactivation rates on temperature varied among the water sources. There was a significant difference in inactivation rate values at the reference temperature between rivers and agricultural waters, wastewaters and agricultural waters, rivers and lakes, and wastewater and lakes. At specific sites, the Q₁₀ equation was more accurate in rivers and coastal waters than in lakes making the value of
Aircraft Survivability: Rotorcraft Survivability. Summer 2010
2010-01-01
protect those who serve to protect us?” The answer is a mixed bag. I am fortunate to have joined a group of dedicated men and women who represent this...and Service subject matter experts on rotorcraft safety and survivability to complete the study and report the results to the Joint Chiefs of...Operations and Support CDD TEMP DT DT/OT LUT IOT &E BLRIP TEMP TEMP LRIP Acquisition & LFT Strategies B C LFT&E Review Requirements Approve TEMPs
Kizer, Nora T; Thaker, Premal H; Gao, Feng; Zighelboim, Israel; Powell, Matthew A; Rader, Janet S; Mutch, David G; Grigsby, Perry W
2011-03-01
The effect of body mass index (BMI) on treatment outcomes for patients with locally advanced cervical carcinoma who receive definitive chemoradiation is unclear. The cohort in this study included all patients with cervical carcinoma (n = 404) who had stage IB(1) disease and positive lymph nodes or stage ≥IB(2) disease and received treatment at the authors' facility between January 1998 and January 2008. The mean follow-up was 47.2 months. BMI was calculated using the National Institute of Health online calculator. BMI categories were created according to the World Health Organization classification system. Primary outcomes were overall survival, disease-free survival, and complication rate. Univariate and multivariate analyses were performed. Kaplan-Meier survival curves were generated and compared using Cox proportional hazard models. On multivariate analysis, compared with normal weight (BMI 18.5-24.9 kg/m(2) ), a BMI 24.9 kg/m(2) , respectively. A BMI 24.9 kg/m(2) (radiation enteritis: 16.7% vs 13.6%, respectively; P = .03; fistula: 11.1% vs 8.8%, respectively; P = .05; bowel obstruction: 33.3% vs 4.4%, respectively; P cervical cancer had diminished overall survival and more complications than normal weight and obese patients. Copyright © 2010 American Cancer Society.
Critical Factors for Inducing Curved Somatosensory Saccades
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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.
Tuning curves, neuronal variability, and sensory coding.
Directory of Open Access Journals (Sweden)
Daniel A Butts
2006-04-01
Full Text Available Tuning curves are widely used to characterize the responses of sensory neurons to external stimuli, but there is an ongoing debate as to their role in sensory processing. Commonly, it is assumed that a neuron's role is to encode the stimulus at the tuning curve peak, because high firing rates are the neuron's most distinct responses. In contrast, many theoretical and empirical studies have noted that nearby stimuli are most easily discriminated in high-slope regions of the tuning curve. Here, we demonstrate that both intuitions are correct, but that their relative importance depends on the experimental context and the level of variability in the neuronal response. Using three different information-based measures of encoding applied to experimentally measured sensory neurons, we show how the best-encoded stimulus can transition from high-slope to high-firing-rate regions of the tuning curve with increasing noise level. We further show that our results are consistent with recent experimental findings that correlate neuronal sensitivities with perception and behavior. This study illustrates the importance of the noise level in determining the encoding properties of sensory neurons and provides a unified framework for interpreting how the tuning curve and neuronal variability relate to the overall role of the neuron in sensory encoding.
Comparison of power curve monitoring methods
Cambron, Philippe; Masson, Christian; Tahan, Antoine; Torres, David; Pelletier, Francis
2017-11-01
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.
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.
Multiphasic growth curve analysis in mice.
Koops, W J; Grossman, M; Michalska, E
1987-01-01
Growth curves of mean body weights were compared to those of individual weights when fitted to data of male and female mice using monophasic (logistic) and triphasic growth functions. Goodness-of-fit was determined by residual variances and Durbin-Watson statistics. These criteria suggest that the triphasic function, with smaller and less correlated residuals, describes the data better than the monophasic function. For the triphasic function, residual variances were higher when fitting individual weights than mean weights. Males had higher residual variances than females. Auto-correlation was negligible when fitting individual weights for males and for females. Parameters of the triphasic function were higher when fitting curves of individual weights than curves of mean weights; differences between curves within sex were small. Parameters were similar for males and females, especially in the first phase of growth. Half asymptotic weights for the second and third phases were higher for males than for females. From these results, it should be clear that using a multiphasic function to describe growth curves in mice provides greater insight for understanding the biology of growth.
Galaxy rotation curves with lognormal density distribution
Marr, John H.
2015-04-01
The lognormal distribution represents the probability of finding randomly distributed particles in a micro canonical ensemble with high entropy. To a first approximation, a modified form of this distribution with a truncated termination may represent an isolated galactic disc, and this disc density distribution model was therefore run to give the best fit to the observational rotation curves for 37 representative galaxies. The resultant curves closely matched the observational data for a wide range of velocity profiles and galaxy types with rising, flat or descending curves in agreement with Verheijen's classification of `R', `F' and `D' type curves, and the corresponding theoretical total disc masses could be fitted to a baryonic Tully-Fisher relation. Nine of the galaxies were matched to galaxies with previously published masses, suggesting a mean excess dynamic disc mass of dex 0.61 ± 0.26 over the baryonic masses. Although questionable with regard to other measurements of the shape of disc galaxy gravitational potentials, this model can accommodate a scenario in which the gravitational mass distribution, as measured via the rotation curve, is confined to a thin plane without requiring a dark matter halo or the use of modified Newtonian dynamics.
[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.
Directory of Open Access Journals (Sweden)
Francely M. Fernandes
2003-09-01
Full Text Available Lucilia cuprina (Wiedemann, 1830 is a cosmopolite blowfly species of medical and veterinary importance because it produces myiasis, mainly in ovine. In order to evaluate the demographic characteristics of this species, survivorship curves for 327 adult males and 323 adult females, from generation F1 maintained under experimental conditions, were obtained. Entropy was utilized as the estimator of the survival pattern to quantify the mortality distribution of individuals as a function of age. The entropy values 0.216 (males and 0.303 (females were obtained. These results denote that, considering the survivorship interval until the death of the last individual for each sex, the males present a tendency of mortality in more advanced age intervals, in comparison with the females.
Is there evidence for a surgeon learning curve for endothelial keratoplasty in Australia?
Keane, Miriam C; Mills, Richard Ad; Coster, Douglas J; Williams, Keryn A
2017-08-01
Expected outcomes from endokeratoplasty may vary with surgeon experience. It was explored whether a surgeon learning curve exists for Descemet stripping endothelial keratoplasties (manual or automated) performed in Australia. This is a prospective cohort study, with various clinical settings. There were 2139 recipients of 2615 endothelial grafts, registered by 85 surgeons between January 2006 and December 2013. Kaplan-Meier survival analyses and Cox proportional hazards regression were used to examine longitudinal graft survival. Manual and automated Descemet stripping endothelial keratoplasties were analysed together. Pearson chi-squared analyses were performed to examine differences amongst groups. Continuity correction was used for 2 × 2 tests, and statistical significance was set at P < 0.05 (two-sided). The main parameter measured was endothelial graft survival. Survival of the first 56 registered grafts was significantly poorer than survival of subsequent grafts (χ2 = 8.83, df = 1, P = 0.003), when data were combined for all surgeons. Surgeon workload influenced graft survival significantly (P < 0.001). This variable was retained in multivariate analysis designed to investigate independent factors influencing graft survival. Primary non-functioning grafts were significantly less likely to be reported for endokeratoplasties performed by surgeons with more than 56 registered grafts, compared with those registering 56 or fewer grafts (4.3% vs. 8.5%; χ2 = 18.38, df = 1, P < 0.001). Our findings suggest that for less experienced or low-volume surgeons, longitudinal graft survival improved once 56 or more endokeratoplasties had been performed, indicative of a learning curve. The learning curve was less apparent for surgeons with 57 or more Descemet stripping endothelial keratoplasties and/or Descemet stripping automated endothelial keratoplasties registered during the 8-year study period. Different learning curves may be anticipated for these
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.
Mapping curved spacetimes into Dirac spinors.
Sabín, Carlos
2017-01-11
We show how to transform a Dirac equation in a curved static spacetime into a Dirac equation in flat spacetime. In particular, we show that any solution of the free massless Dirac equation in a 1 + 1 dimensional flat spacetime can be transformed via a local phase transformation into a solution of the corresponding Dirac equation in a curved static background, where the spacetime metric is encoded into the phase. In this way, the existing quantum simulators of the Dirac equation can naturally incorporate curved static spacetimes. As a first example we use our technique to obtain solutions of the Dirac equation in a particular family of interesting spacetimes in 1 + 1 dimensions.
BEST FIT MODEL FOR YIELD CURVE ESTIMATION
Directory of Open Access Journals (Sweden)
Zdravka Aljinović
2012-12-01
Full Text Available Yield curve represents a relationship between the rate of return and maturity of certain securities. A range of activities on the market is determined by the abovementioned relationship; therefore its significance is unquestionable. Besides that, its shape reflects the shape of the economy, i.e. it can predict recession. These are the reasons why it is very important to properly and accurately estimate the yield curve. There are various models evolved for its estimation; however the most used are parametric models: Nelson-Siegel model and Svensson model. In this paper the yield curves are estimated on Croatian financial market, based on weekly data in years 2011 and 2012 both with Nelson-Siegel and Svensson model, and the obtained results are compared.
Caccamo, M.; Veerkamp, R.F.; Licitra, G.; Petriglieri, R.; Terra, La F.; Pozzebon, A.; Ferguson, J.D.
2012-01-01
The objective of this study was to examine the effect of the chemical composition of a total mixed ration (TMR) tested quarterly from March 2006 through December 2008 for milk, fat, and protein yield curves for 27 herds in Ragusa, Sicily. Before this study, standard yield curves were generated on
Hoffmann, AC; Berrino, A; Ray, MB; Arastoopour, H
1999-01-01
The factors influencing the shapes of cyclone grade efficiency curves generated by Computational Fluid Dynamics (CFD) and Lagrangian particle tracking are studied. Two software packages SPRINT and FLUENT were used for a complete picture. Computed curves both with and without the effect of turbulent
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.
Choi, Y S; Ahn, S S; Lee, H-J; Chang, J H; Kang, S-G; Kim, E H; Kim, S H; Lee, S-K
2017-08-01
Although perfusion and permeability MR parameters have known to have prognostic value, they have reproducibility issues. Our aim was to evaluate whether the initial area under the time-to-signal intensity curve (IAUC) derived from dynamic contrast-enhanced MR imaging can improve prognosis prediction in patients with glioblastoma with known MGMT status. We retrospectively examined 88 patients with glioblastoma who underwent preoperative dynamic contrast-enhanced MR imaging. The means of IAUC values at 30 and 60 seconds (IAUC30mean and IAUC60mean) were extracted from enhancing tumors. The prognostic values of IAUC parameters for overall survival and progression-free survival were assessed with log-rank tests, according to the MGMT status. Multivariate overall survival and progression-free survival models before and after adding the IAUC parameters as covariates were explored by net reclassification improvement after receiver operating characteristic analysis for 1.5-year overall survival and 1-year progression-free survival and by random survival forest. High IAUC parameters were associated with worse overall survival and progression-free survival in the unmethylated MGMT group, but not in the methylated group. In the unmethylated MGMT group, 1.5-year overall survival and 1-year progression-free survival prediction improved significantly after adding IAUC parameters (overall survival area under the receiver operating characteristic curve, 0.86; progression-free survival area under the receiver operating characteristic curve, 0.74-0.76) to the model with other prognostic factors (overall survival area under the receiver operating characteristic curve, 0.81; progression-free survival area under the receiver operating characteristic curve, 0.69; P < .05 for all) except in the case of IAUC60mean for 1-year progression-free survival prediction (P = .059). Random survival forest models indicated that the IAUC parameters were the second or most important predictors in the
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
Charged particles constrained to a curved surface
Müller, Thomas
2012-01-01
We study the motion of charged particles constrained to arbitrary two-dimensional curved surfaces but interacting in three-dimensional space via the Coulomb potential. To speed-up the interaction calculations, we use the parallel compute capability of the Compute Unified Device Architecture (CUDA) of todays graphics boards. The particles and the curved surfaces are shown using the Open Graphics Library (OpenGL). The paper is intended to give graduate students, who have basic experiences with electrostatics and differential geometry, a deeper understanding in charged particle interactions and a short introduction how to handle a many particle system using parallel computing on a single home computer
Strange Curves, Counting Rabbits, & Other Mathematical Explorations
Ball, Keith
2011-01-01
How does mathematics enable us to send pictures from space back to Earth? Where does the bell-shaped curve come from? Why do you need only 23 people in a room for a 50/50 chance of two of them sharing the same birthday? In Strange Curves, Counting Rabbits, and Other Mathematical Explorations, Keith Ball highlights how ideas, mostly from pure math, can answer these questions and many more. Drawing on areas of mathematics from probability theory, number theory, and geometry, he explores a wide range of concepts, some more light-hearted, others central to the development of the field and used dai
Conformal metamaterial absorber for curved surface.
Jang, Youngsoo; Yoo, Minyeong; Lim, Sungjoon
2013-10-07
In this paper, three different unit cells are designed on the basis split-ring-cross resonators, and each unit cell has an absorption rate greater than 90% at incident angles of 0°, 30°, and 45°, respectively. They are non-periodically placed in three different zones on the curved surface. Therefore, the proposed conformal metamaterial absorber can achieve a high absorption rate. The performance of the proposed absorber is compared with that of a metallic curved surface and a conformal metamaterial absorber with the same unit cells.
Space-filling curves for image compression
Moghaddam, Baback; Hintz, Kenneth J.; Stewart, Clayton V.
1991-08-01
This paper outlines the use of space-filling curves in transform image compression. Specifically, a space-filling Hilbert curve is used for mapping the two-dimensional image into a suitable one-dimensional representation. Compared to simple raster-scans, this topological mapping is spatially non-disruptive and tends to preserve local pixel correlations in the original two-dimensional image. Standard transform coefficient reduction and coding techniques can then be applied to the one-dimensional representation for the purposes of data compression. The advantages of the one-dimensional coding, in terms of computational cost and subjective image quality, are also discussed.
Generalized Timelike Mannheim Curves in Minkowski Space-Time
Directory of Open Access Journals (Sweden)
M. Akyig~it
2011-01-01
Full Text Available We give the definition of generalized timelike Mannheim curve in Minkowski space-time . The necessary and sufficient conditions for the generalized timelike Mannheim curve are obtained. We show some characterizations of generalized Mannheim curve.
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
Diameter Effect Curve and Detonation Front Curvature Measurements for ANFO
Catanach, R. A.; Hill, L. G.
2002-07-01
Diameter effect and front curvature measurements are reported for rate stick experiments on commercially available prilled ANFO (ammonium-nitrate/fuel-oil) at ambient temperature. The shots were fired in paper tubes so as to provide minimal confinement. Diameters ranged from 77 mm (approximately failure diameter) to 205 mm, with the tube length being ten diameters in all cases. Each detonation wave shape was fit with an analytic form, from which the local normal velocity Dn, and local total curvature kappa, were generated as a function of radius R, then plotted parametrically to generate a Dn(kappa) function. The observed behavior deviates substantially from that of previous explosives, for which curves for different diameters overlay well for small kappa but diverge for large kappa, and for which kappa increases monotonically with R. For ANFO, we find that Dn(kappa) curves for individual sticks 1) show little or no overlap--with smaller sticks lying to the right of larger ones, 2) exhibit a large velocity deficit with little kappa variation, and 3) reach a peak kappa at an intermediate R.
Water retention curve for hydrate‐bearing sediments
National Research Council Canada - National Science Library
Dai, Sheng; Santamarina, J. Carlos
2013-01-01
.... The determination of the water retention curve for hydrate‐bearing sediments faces experimental difficulties, and most studies assume constant water retention curves regardless of hydrate saturation...
Chilling curves for Piaractus mesopotamicus (Holmberg, 1887) embryos stored at -8°C.
Lopes, Taís da S; Streit, Danilo Pedro; Fornari, Darci Carlos; de Oliveira, Diego; Ribeiro, Ricardo Pereira; Romagosa, Elizabeth
2013-11-01
The present study investigates the effect of different slow chilling curves on the storage of pacu (Piaractus mesopotamicus) embryos submitted to chilling at -8°C. Embryos at the blastopore closure stage were divided into two groups: G1 - embryos exposed to cryoprotectant solution containing methanol (10%) and sucrose (0.5 M), treated as follows: (T1) taken directly from room temperature to the refrigerator without being submitted to the curve; (T2) chilling curve of 0.5°C/min; and (T3) chilling curve of 1°C/min; and G2 - the cryoprotectant solution alone was submitted to these same temperatures, receiving the embryos only after temperature had decreased, corresponding to treatments T4, T5 and T6, respectively. Treatments were kept at -8°C for a period of 6 h. Embryo development was evaluated for each treatment, with six replicates in an entirely randomized design. Survival among embryos not submitted to refrigeration was 94.3 ± 8.05%. Percentage of total larvae (TL) and addled eggs (AE) did not differ statistically between the groups, although percentage of swimming larvae (SL) exhibited higher values in G1 for the 1°C/min curve. Furthermore, when comparing the three chilling curves, a decrease of 1°C/min resulted in the highest TL percentage (90.85%), followed by the 0.5°C/min curve (78.52%). Thus, the use of 1°C/min chilling curves is recommended for P. mesopotamicus embryos stored for 6 h at -8°C.
Survivability is more fundamental than evolvability.
Directory of Open Access Journals (Sweden)
Michael E Palmer
Full Text Available For a lineage to survive over long time periods, it must sometimes change. This has given rise to the term evolvability, meaning the tendency to produce adaptive variation. One lineage may be superior to another in terms of its current standing variation, or it may tend to produce more adaptive variation. However, evolutionary outcomes depend on more than standing variation and produced adaptive variation: deleterious variation also matters. Evolvability, as most commonly interpreted, is not predictive of evolutionary outcomes. Here, we define a predictive measure of the evolutionary success of a lineage that we call the k-survivability, defined as the probability that the lineage avoids extinction for k generations. We estimate the k-survivability using multiple experimental replicates. Because we measure evolutionary outcomes, the initial standing variation, the full spectrum of generated variation, and the heritability of that variation are all incorporated. Survivability also accounts for the decreased joint likelihood of extinction of sub-lineages when they 1 disperse in space, or 2 diversify in lifestyle. We illustrate measurement of survivability with in silico models, and suggest that it may also be measured in vivo using multiple longitudinal replicates. The k-survivability is a metric that enables the quantitative study of, for example, the evolution of 1 mutation rates, 2 dispersal mechanisms, 3 the genotype-phenotype map, and 4 sexual reproduction, in temporally and spatially fluctuating environments. Although these disparate phenomena evolve by well-understood microevolutionary rules, they are also subject to the macroevolutionary constraint of long-term survivability.
Energy Technology Data Exchange (ETDEWEB)
Lee, Hyun Jin [Department of Radiation Oncology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Han, Seungbong [Department of Clinical Epidemiology and Biostatistics, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Kim, Young Seok, E-mail: ysk@amc.seoul.kr [Department of Radiation Oncology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Nam, Joo-Hyun [Department of Obstetrics and Gynecology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul (Korea, Republic of); Kim, Hak Jae [Department of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Jae Weon [Department of Obstetrics and Gynecology, Seoul National University Hospital, Seoul (Korea, Republic of); Park, Won [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Byoung-Gie [Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Jin Hee [Department of Radiation Oncology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu (Korea, Republic of); Cha, Soon Do [Department of Obstetrics and Gynecology, Dongsan Medical Center, Keimyung University School of Medicine, Daegu (Korea, Republic of); Kim, Juree [Department of Radiation Oncology, Cheil General Hospital and Women' s Healthcare Center, Kwandong University, College of Medicine, Seoul (Korea, Republic of); Lee, Ki-Heon [Department of Obstetrics and Gynecology, Cheil General Hospital and Women' s Healthcare Center, Kwandong University, College of Medicine, Seoul (Korea, Republic of); Yoon, Mee Sun [Department of Radiation Oncology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Jeollanam-do (Korea, Republic of); and others
2013-11-15
Purpose: A nomogram is a predictive statistical model that generates the continuous probability of a clinical event such as death or recurrence. The aim of the study was to construct a nomogram to predict 5-year overall survival after postoperative radiation therapy for stage IB to IIA cervical cancer. Methods and Materials: The clinical data from 1702 patients with early-stage cervical cancer, treated at 10 participating hospitals from 1990 to 2011, were reviewed to develop a prediction nomogram based on the Cox proportional hazards model. Demographic, clinical, and pathologic variables were included and analyzed to formulate the nomogram. The discrimination and calibration power of the model was measured using a concordance index (c-index) and calibration curve. Results: The median follow-up period for surviving patients was 75.6 months, and the 5-year overall survival probability was 87.1%. The final model was constructed using the following variables: age, number of positive pelvic lymph nodes, parametrial invasion, lymphovascular invasion, and the use of concurrent chemotherapy. The nomogram predicted the 5-year overall survival with a c-index of 0.69, which was superior to the predictive power of the International Federation of Gynecology and Obstetrics (FIGO) staging system (c-index of 0.54). Conclusions: A survival-predicting nomogram that offers an accurate level of prediction and discrimination was developed based on a large multi-center study. The model may be more useful than the FIGO staging system for counseling individual patients regarding prognosis.
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
Growth curves for girls with Turner syndrome.
Bertapelli, Fabio; Barros-Filho, Antonio de Azevedo; Antonio, Maria Ângela Reis de Góes Monteiro; Barbeta, Camila Justino de Oliveira; de Lemos-Marini, Sofia Helena Valente; Guerra-Junior, Gil
2014-01-01
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.
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.
Trigonometric Characterization of Some Plane Curves
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 3. Trigonometric Characterization of Some Plane Curves. B Barua J Das. General Article Volume 20 ... Author Affiliations. B Barua1 J Das1. Indian Society of Nonlinear Analysts (INSA), 248 B, B B Chatterjee Road, Kolkata 700 042, W B, India ...
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
Focus on Physics: The Delightful Catenary Curve
Hewitt, Paul G.
2017-01-01
When teaching how "tension" and "compression" relate to geometrical structures such as bridges, arches, and domes, The author shows a picture of the Notre Dame Cathedral in Paris, completed in the 14th century, and presents a lesson on using the curve called a catenary to explain how he teaches about tension and compression…
Simulation of experimental breakthrough curves using multiprocess ...
Indian Academy of Sciences (India)
Abstract. In this paper, we have studied the behaviour of reactive solute trans- port through stratified porous medium under the influence of multi-process non- equilibrium transport model. Various experiments were carried out in the laboratory and the experimental breakthrough curves were observed at spatially placed sam ...
Comparison and evaluation of mathematical lactation curve ...
African Journals Online (AJOL)
p2492989
Abstract. Describing lactation in mammals using a lactation curve aims to provide a concise summary of the pattern of milk yield and valuable information about the biological and economic efficiency of the animal or herd under consideration. A total of 106 581 monthly test-day milk records collected from 12 677 Tehran.
The environmental Kuznets curve for water pollution
African Journals Online (AJOL)
The main aim of this study was to analyze evidence of an environmental Kuznets curve for water pollution in the developing and developed countries. The study was conducted based on a panel data set of 54 countries – that were categorized into six groups of “developed countries”, “developing countries”, “developed ...
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 ...
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...
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.)
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...
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 ...
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…
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...
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.
Characteristic Classes for Curves of Genus One
Taelman, L.
2015-01-01
We compute the cohomology of the stackM1 over C with coefficients in Z[12 ], and in low degrees with coefficients in Z. Cohomology classes onM1 give rise to characteristic classes, cohomological invariants of families of curves of genus one. We prove a number of vanishing results for those
The characteristic numbers of quartic plane curves
Vakil, Ravi
1998-01-01
The characteristic numbers of smooth plane quartics are computed using intersection theory on a component of the moduli space of stable maps. This completes the verification of Zeuthen's prediction of characteristic numbers of smooth plane curves. A short sketch of a computation of the characteristic numbers of plane cubics is also given as an illustration.
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...
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.
Superconformal quantum field theory in curved spacetime
de Medeiros, Paul; Hollands, Stefan
2013-09-01
By conformally coupling vector and hyper multiplets in Minkowski space, we obtain a class of field theories with extended rigid conformal supersymmetry on any Lorentzian 4-manifold admitting twistor spinors. We construct the conformal symmetry superalgebras which describe classical symmetries of these theories and derive an appropriate BRST operator in curved spacetime. In the process, we elucidate the general framework of cohomological algebra which underpins the construction. We then consider the corresponding perturbative quantum field theories. In particular, we examine the conditions necessary for conformal supersymmetries to be preserved at the quantum level, i.e. when the BRST operator commutes with the perturbatively defined S-matrix, which ensures superconformal invariance of amplitudes. To this end, we prescribe a renormalization scheme for time-ordered products that enter the perturbative S-matrix and show that such products obey certain Ward identities in curved spacetime. These identities allow us to recast the problem in terms of the cohomology of the BRST operator. Through a careful analysis of this cohomology, and of the renormalization group in curved spacetime, we establish precise criteria which ensure that all conformal supersymmetries are preserved at the quantum level. As a by-product, we provide a rigorous proof that the beta-function for such theories is one-loop exact. We also briefly discuss the construction of chiral rings and the role of non-perturbative effects in curved spacetime.
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 ...
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.
Dual kinetic curves in reversible electrochemical systems.
Directory of Open Access Journals (Sweden)
Michael J Hankins
Full Text Available We introduce dual kinetic chronoamperometry, in which reciprocal relations are established between the kinetic curves of electrochemical reactions that start from symmetrical initial conditions. We have performed numerical and experimental studies in which the kinetic curves of the electron-transfer processes are analyzed for a reversible first order reaction. Experimental tests were done with the ferrocyanide/ferricyanide system in which the concentrations of each component could be measured separately using the platinum disk/gold ring electrode. It is shown that the proper ratio of the transient kinetic curves obtained from cathodic and anodic mass transfer limited regions give thermodynamic time invariances related to the reaction quotient of the bulk concentrations. Therefore, thermodynamic time invariances can be observed at any time using the dual kinetic curves for reversible reactions. The technique provides a unique possibility to extract the non-steady state trajectory starting from one initial condition based only on the equilibrium constant and the trajectory which starts from the symmetrical initial condition. The results could impact battery technology by predicting the concentrations and currents of the underlying non-steady state processes in a wide domain from thermodynamic principles and limited kinetic information.
Is the Water Heating Curve as Described?
Riveros, H. G.; Oliva, A. I.
2008-01-01
We analysed the heating curve of water which is described in textbooks. An experiment combined with some simple heat transfer calculations is discussed. The theoretical behaviour can be altered by changing the conditions under which the experiment is modelled. By identifying and controlling the different parameters involved during the heating…
A life-cycle model with ambiguous survival beliefs
Groneck, Max; Ludwig, Alexander; Zimper, Alexander
Based on a cognitive notion of neo-additive capacities reflecting likelihood insensitivity with respect to survival chances, we construct a Choquet Bayesian learning model over the life-cycle that generates a motivational notion of neo-additive survival beliefs expressing ambiguity attitudes. We
Rendering of specular curved objects in polygon-based computer holography.
Nishi, Hirohito; Matsushima, Kyoji
2017-05-01
A realistic rendering technique is presented for creating large-scale computer-generated holograms. The technique is based on the polygon-based method, but allows specular curved surfaces to be reconstructed without increasing the number of polygons. In this technique, specular flat surfaces are transformed into curved surfaces. This is achieved by controlling the direction of reflected light, using fragmentary plane waves. An actual large-scale computer-generated hologram is created, and is used to verify the validity and practicality of the technique.
Radiation survival of food pathogens in complex media.
Dyer, J K; Anderson, A W; Dutiyabodhi, P
1966-01-01
When 15 bacterial species representing genera associated with food-borne diseases were irradiated individually, all except Escherichia coli and Streptococcus faecalis showed typical linear dose-survival curves in Hartsell's broth. The minimal lethal dose (MLD) for the organisms tested ranged from 3.0 x 10(5) to 6.0 x 10(5) rad. Salmonella paratyphi B, S. wichita, S. typhi, E. coli, and S. faecalis were found to be the least sensitive to radiation. In commercially canned crabmeat the survival curves of S. typhi, S. paratyphi B, and S. wichita exhibited to varying degrees an initial linear death decline with increasing radiation doses, followed by a distinct tailing effect caused by survival of low numbers at the higher doses. The above species of Salmonella were further individually subjected to gamma-radiation in various dilutions of crabmeat. The "tailing effect" gradually disappeared, with the dose-survival curve tending to become linear as the concentration of the crabmeat decreased.
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.
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.
2013-01-15
pp.289-302 ( Impact factor : 2.09). 2. Julic, J. and Zuo, Y. (2012). “An RFID Survivability Impact Model in the Military Domain”, Proc. of 18 th...Availability, Reliability and Security, 40(4), pp. 406-418 ( Impact factor : 2.016). 10. Zuo, Y. (2010). “A Holistic Approach for Specification of Security... Impact factor : 1.596). 20. Zuo, Y., Pimple, M. and Lande, S. (2009). “A Framework for RFID Survivability Requirement Analysis and Specification”, Proc
A stochastic evolutionary model for survival dynamics
Fenner, Trevor; Levene, Mark; Loizou, George
2014-09-01
The recent interest in human dynamics has led researchers to investigate the stochastic processes that explain human behaviour in different contexts. Here we propose a generative model to capture the essential dynamics of survival analysis, traditionally employed in clinical trials and reliability analysis in engineering. In our model, the only implicit assumption made is that the longer an actor has been in the system, the more likely it is to have failed. We derive a power-law distribution for the process and provide preliminary empirical evidence for the validity of the model from two well-known survival analysis data sets.
Can a Bayesian Belief Network Be Used to Estimate 1-year Survival in Patients With Bone Sarcomas?
Nandra, Rajpal; Parry, Michael; Forsberg, Jonathan; Grimer, Robert
2017-06-01
Extremity sarcoma has a preponderance to present late with advanced stage at diagnosis. It is important to know why these patients die early from sarcoma and to predict those at high risk. Currently we have mid- to long-term outcome data on which to counsel patients and support treatment decisions, but in contrast to other cancer groups, very little on short-term mortality. Bayesian belief network modeling has been used to develop decision-support tools in various oncologic diagnoses, but to our knowledge, this approach has not been applied to patients with extremity sarcoma. We sought to (1) determine whether a Bayesian belief network could be used to estimate the likelihood of 1-year mortality using receiver operator characteristic analysis; (2) describe the hierarchal relationships between prognostic and outcome variables; and (3) determine whether the model was suitable for clinical use using decision curve analysis. We considered all patients treated for primary bone sarcoma between 1970 and 2012, and excluded secondary metastasis, presentation with local recurrence, and benign tumors. The institution's database yielded 3499 patients, of which six (0.2%) were excluded. Data extracted for analysis focused on patient demographics (age, sex), tumor characteristics at diagnosis (size, metastasis, pathologic fracture), survival, and cause of death. A Bayesian belief network generated conditional probabilities of variables and survival outcome at 1 year. A lift analysis determined the hierarchal relationship of variables. Internal validation of 699 test patients (20% dataset) determined model accuracy. Decision curve analysis was performed comparing net benefit (capped at 85.5%) for all threshold probabilities (survival output from model). We successfully generated a Bayesian belief network with five first-degree associates and describe their conditional relationship with survival after the diagnosis of primary bone sarcoma. On internal validation, the resultant
Gilroy, James J; Virzi, Thomas; Boulton, Rebecca L; Lockwood, Julie L
2012-07-01
Survival estimates generated from live capture-mark-recapture studies may be negatively biased due to the permanent emigration of marked individuals from the study area. In the absence of a robust analytical solution, researchers typically sidestep this problem by simply reporting estimates using the term "apparent survival." Here, we present a hierarchical Bayesian multistate model designed to estimate true survival by accounting for predicted rates of permanent emigration. Initially we use dispersal kernels to generate spatial projections of dispersal probability around each capture location. From these projections, we estimate emigration probability for each marked individual and use the resulting values to generate bias-adjusted survival estimates from individual capture histories. When tested using simulated data sets featuring variable detection probabilities, survival rates, and dispersal patterns, the model consistently eliminated negative biases shown by apparent survival estimates from standard models. When applied to a case study concerning juvenile survival in the endangered Cape Sable Seaside Sparrow (Ammodramus maritimus mirabilis), bias-adjusted survival estimates increased more than twofold above apparent survival estimates. Our approach is applicable to any capture-mark-recapture study design and should be particularly valuable for organisms with dispersive juvenile life stages.
A dose-response curve for biodosimetry from a 6 MV electron linear accelerator
Energy Technology Data Exchange (ETDEWEB)
Lemos-Pinto, M.M.P.; Cadena, M.; Santos, N.; Fernandes, T.S.; Borges, E.; Amaral, A., E-mail: marcelazoo@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear
2015-10-15
Biological dosimetry (biodosimetry) is based on the investigation of radiation-induced biological effects (biomarkers), mainly dicentric chromosomes, in order to correlate them with radiation dose. To interpret the dicentric score in terms of absorbed dose, a calibration curve is needed. Each curve should be constructed with respect to basic physical parameters, such as the type of ionizing radiation characterized by low or high linear energy transfer (LET) and dose rate. This study was designed to obtain dose calibration curves by scoring of dicentric chromosomes in peripheral blood lymphocytes irradiated in vitro with a 6 MV electron linear accelerator (Mevatron M, Siemens, USA). Two software programs, CABAS (Chromosomal Aberration Calculation Software) and Dose Estimate, were used to generate the curve. The two software programs are discussed; the results obtained were compared with each other and with other published low LET radiation curves. Both software programs resulted in identical linear and quadratic terms for the curve presented here, which was in good agreement with published curves for similar radiation quality and dose rates. (author)
A Simple and Effective Clustering Algorithm for Multispectral Images Using Space-Filling Curves
Zhang, Jian; Kamata, Sei-Ichiro
With the wide usage of multispectral images, a fast efficient multidimensional clustering method becomes not only meaningful but also necessary. In general, to speed up the multidimensional images' analysis, a multidimensional feature vector should be transformed into a lower dimensional space. The Hilbert curve is a continuous one-to-one mapping from N-dimensional space to one-dimensional space, and can preserves neighborhood as much as possible. However, because the Hilbert curve is generated by a recurve division process, ‘Boundary Effects’ will happen, which means data that are close in N-dimensional space may not be close in one-dimensional Hilbert order. In this paper, a new efficient approach based on the space-filling curves is proposed for classifying multispectral satellite images. In order to remove ‘Boundary Effects’ of the Hilbert curve, multiple Hilbert curves, z curves, and the Pseudo-Hilbert curve are used jointly. The proposed method extracts category clusters from one-dimensional data without computing any distance in N-dimensional space. Furthermore, multispectral images can be analyzed hierarchically from coarse data distribution to fine data distribution in accordance with different application. The experimental results performed on LANDSAT data have demonstrated that the proposed method is efficient to manage the multispectral images and can be applied easily.
Directory of Open Access Journals (Sweden)
Mohsen Gerami
2017-02-01
Full Text Available Fragility curves play an important role in damage assessment of buildings. Probability of damage induction to the structure against seismic events can be investigated upon generation of afore mentioned curves. In current research 360 time history analyses have been carried out on structures of 3, 10 and 20 story height and subsequently fragility curves have been adopted. The curves are developed based on two indices of inter story drifts and equivalent strip axial strains of the shear wall. Time history analysis is carried out in Perform 3d considering 10 far field seismograms and 10 near fields. Analysis of low height structures revealed that they are more vulnerable in accelerations lower than 0.8 g in near field earthquakes because of higher mode effects. Upon the generated fragility curves it was observed that middle and high structures have more acceptable performance and lower damage levels compared to low height structures in both near and far field seismic hazards.
Survivability via Control Objectives
Energy Technology Data Exchange (ETDEWEB)
CAMPBELL,PHILIP L.
2000-08-11
Control objectives open an additional front in the survivability battle. A given set of control objectives is valuable if it represents good practices, it is complete (it covers all the necessary areas), and it is auditable. CobiT and BS 7799 are two examples of control objective sets.
DEFF Research Database (Denmark)
Bille, Trine; Jensen, Søren
2017-01-01
The literature of cultural economics generally finds that an artistic education has no significant impact on artists’ income and careers in the arts. In our research, we have readdressed this question by looking at the artists’ survival in the arts occupations. The results show that an artistic...... education has a significant impact on artists’ careers in the arts and we find important industry differences....
Aldrich, Richard
2010-01-01
This article provides a brief overview of current approaches to education and concludes that none of these is sufficient to meet the challenges that now face the human race. It argues instead for a new concept of education for survival. (Contains 1 note.)
Flexible survival regression modelling
DEFF Research Database (Denmark)
Cortese, Giuliana; Scheike, Thomas H; Martinussen, Torben
2009-01-01
Regression analysis of survival data, and more generally event history data, is typically based on Cox's regression model. We here review some recent methodology, focusing on the limitations of Cox's regression model. The key limitation is that the model is not well suited to represent time-varyi...
Holloway, Clark; Youngblood, Stuart A.
1986-01-01
Examined survival rates after retirement in a large corporation. A regression analysis was performed to control for age, sex, job status, and type of work differences that may influence longevity. Short-term suvivors seemed to undergo a different adjustment process than long-term survivors. (Author/ABL)
On genera of curves from high-loop generalized unitarity cuts
Huang, Rijun; Zhang, Yang
2013-04-01
Generalized unitarity cut of a Feynman diagram generates an algebraic system of polynomial equations. At high-loop levels, these equations may define a complex curve or a (hyper-)surface with complicated topology. We study the curve cases, i.e., a 4-dimensional L-loop diagram with (4 L-1) cuts. The topology of a complex curve is classified by its genus. Hence in this paper, we use computational algebraic geometry to calculate the genera of curves from two and three-loop unitarity cuts. The global structure of degenerate on-shell equations under some specific kinematic configurations is also sketched. The genus information can also be used to judge if a unitary cut solution could be rationally parameterized.
Part 5: Receiver Operating Characteristic Curve and Area under the Curve
Directory of Open Access Journals (Sweden)
Saeed Safari
2016-04-01
Full Text Available Multiple diagnostic tools are used by emergency physicians,every day. In addition, new tools are evaluated to obtainmore accurate methods and reduce time or cost of conventionalones. In the previous parts of this educationalseries, we described diagnostic performance characteristicsof diagnostic tests including sensitivity, specificity, positiveand negative predictive values, and likelihood ratios. Thereceiver operating characteristics (ROC curve is a graphicalpresentation of screening characteristics. ROC curve is usedto determine the best cutoff point and compare two or moretests or observers by measuring the area under the curve(AUC. In this part of our educational series, we explain ROCcurve and two methods to determine the best cutoff value.
Continuous measurement of soil-water characteristic curves at low suction levels
Ray, Richard; Bene, Katalin
2017-04-01
The soil-water characteristic curve (SWCC) is an important piece of information for understanding unsaturated soil behavior. With few exceptions, most of the SWCCs are developed as discrete points and are typically generated under drying path. This study presents results from automated tests that typically draw suction values to about 1 bar. Tempe cells are used with the axis translation method to generate the curves. Soils tested include fine sand, silty, and clayey sands. While a typical test starts in a saturated state and generates a drying curve, the test can be reversed any number of times to produce hysteresis behavior. Another advantage to the method is time efficiency since a curve with thousands of data points are produced in less than a week. However, careful consideration has to be made with regard to extraction rate, especially as the specimen becomes dryer. Several data sets are presented illustrating good and problematic behavior as well as hysteresis. Some suggestions are given concerning the selection of extraction rates or adjusting curves to account for extraction rate effects.
Mukkamala, R.; Cohen, R. J.; Mark, R. G.
2002-01-01
Guyton developed a popular approach for understanding the factors responsible for cardiac output (CO) regulation in which 1) the heart-lung unit and systemic circulation are independently characterized via CO and venous return (VR) curves, and 2) average CO and right atrial pressure (RAP) of the intact circulation are predicted by graphically intersecting the curves. However, this approach is virtually impossible to verify experimentally. We theoretically evaluated the approach with respect to a nonlinear, computational model of the pulsatile heart and circulation. We developed two sets of open circulation models to generate CO and VR curves, differing by the manner in which average RAP was varied. One set applied constant RAPs, while the other set applied pulsatile RAPs. Accurate prediction of intact, average CO and RAP was achieved only by intersecting the CO and VR curves generated with pulsatile RAPs because of the pulsatility and nonlinearity (e.g., systemic venous collapse) of the intact model. The CO and VR curves generated with pulsatile RAPs were also practically independent. This theoretical study therefore supports the validity of Guyton's graphical analysis.
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.
Learning curve in fenestrated and branched grafting.
Martin-Gonzalez, Teresa; Mastracci, Tara M
2017-04-01
In surgical practice new technologies and techniques require a period of adjustment before the main operator becomes familiar with the new procedure, improving the results and the performances. This period, called learning curve, could be applied into the endovascular aortic treatment. The CUSUM technique had been used to define the learning curve in new procedures and through the literature some studies applied it to demonstrate the improving outcomes in complex endovascular aneurysm repair during increasing experience time. However, in the complex endovascular field this period included also other factors besides the proficiency in the deployment, as the improvement in patient selection and device design, making difficult to determine the level of experience needed to become an expert.
A Functional Equation Originating from Elliptic Curves
Directory of Open Access Journals (Sweden)
Jae-Hyeong Bae
2008-04-01
Full Text Available We obtain the general solution and the stability of the functional equation f(x+y+z,u+v+w+f(x+yÃ¢ÂˆÂ’z,u+v+w+2f(x,uÃ¢ÂˆÂ’w+2f(y,vÃ¢ÂˆÂ’w=f(x+y,u+w+f(x+y,v+w+f(x+z,u+w+f(xÃ¢ÂˆÂ’z,u+vÃ¢ÂˆÂ’w+f(y+z,v+w+f(yÃ¢ÂˆÂ’z,u+vÃ¢ÂˆÂ’w. The function f(x,y=x3+ax+bÃ¢ÂˆÂ’y2 having level curves as elliptic curves is a solution of the above functional equation.
Broadband Approximations for Doubly Curved Reflector Antenna
Directory of Open Access Journals (Sweden)
V. Schejbal
2010-12-01
Full Text Available The broadband approximations for shaped-beam doubly curved reflector antennas with primary feed (rectangular horn producing uniform amplitude and phase aperture distribution are derived and analyzed. They are very valuable for electromagnetic compatibility analyses both from electromagnetic interference and susceptibility point of view, because specialized more accurate methods such as physical optics are only used by antenna designers. To allow quick EMC analyses, typical values, beamwidth changes, sidelobe levels and aperture efficiencies are given for frequency changes approximately up to four times operating frequency. A comparison of approximated and measured patterns of doubly curved reflector antennas shows that the given approximation could be reliably used for analyses of pattern changes due to very broad frequency changes.
Curved butterfly bileaflet prosthetic cardiac valve
Energy Technology Data Exchange (ETDEWEB)
McQueen, D.M.; Peskin, C.S.
1991-06-25
An annular valve body having a central passageway for the flow of blood with two curved leaflets is described. Each of the leaflets is pivotally supported on an accentric positioned axis in the central passageway for moving between a closed position and an open position. The leaflets are curved in a plane normal to the eccentric axis and positioned with the convex side of the leaflets facing each other when the leaflets are in the open position. Various parameters such as the curvature of the leaflets, the location of the eccentric axis, and the maximum opening angle of the leaflets are optimized according to the following performance criteria: maximize the minimum peak velocity through the valve, maximize the net stroke volume, and minimize the mean forward pressure difference, thereby reducing thrombosis and improving the hemodynamic performance. 26 figures.
Curved butterfly bileaflet prosthetic cardiac valve
Energy Technology Data Exchange (ETDEWEB)
McQueen, David M. (185 Hillside Ave., Chatham, NJ 07928); Peskin, Charles S. (186 Harrard Dr., Hartsdale, NY 10530)
1991-06-25
An annular valve body having a central passageway for the flow of blood therethrough with two curved leaflets each of which is pivotally supported on an accentric positioned axis in the central passageway for moving between a closed position and an open position. The leaflets are curved in a plane normal to the eccentric axis and positioned with the convex side of the leaflets facing each other when the leaflets are in the open position. Various parameters such as the curvature of the leaflets, the location of the eccentric axis, and the maximum opening angle of the leaflets are optimized according to the following performance criteria: maximize the minimum peak velocity through the valve, maximize the net stroke volume, and minimize the mean forward pressure difference, thereby reducing thrombosis and improving the hemodynamic performance.
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...
Field Theory on Curved Noncommutative Spacetimes
Directory of Open Access Journals (Sweden)
Alexander Schenkel
2010-08-01
Full Text Available We study classical scalar field theories on noncommutative curved spacetimes. Following the approach of Wess et al. [Classical Quantum Gravity 22 (2005, 3511 and Classical Quantum Gravity 23 (2006, 1883], we describe noncommutative spacetimes by using (Abelian Drinfel'd twists and the associated *-products and *-differential geometry. In particular, we allow for position dependent noncommutativity and do not restrict ourselves to the Moyal-Weyl deformation. We construct action functionals for real scalar fields on noncommutative curved spacetimes, and derive the corresponding deformed wave equations. We provide explicit examples of deformed Klein-Gordon operators for noncommutative Minkowski, de Sitter, Schwarzschild and Randall-Sundrum spacetimes, which solve the noncommutative Einstein equations. We study the construction of deformed Green's functions and provide a diagrammatic approach for their perturbative calculation. The leading noncommutative corrections to the Green's functions for our examples are derived.
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.
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.
Daylight calculations using constant luminance curves
Energy Technology Data Exchange (ETDEWEB)
Betman, E. [CRICYT, Mendoza (Argentina). Laboratorio de Ambiente Humano y Vivienda
2005-02-01
This paper presents a simple method to manually estimate daylight availability and to make daylight calculations using constant luminance curves calculated with local illuminance and irradiance data and the all-weather model for sky luminance distribution developed in the Atmospheric Science Research Center of the University of New York (ARSC) by Richard Perez et al. Work with constant luminance curves has the advantage that daylight calculations include the problem's directionality and preserve the information of the luminous climate of the place. This permits accurate knowledge of the resource and a strong basis to establish conclusions concerning topics related to the energy efficiency and comfort in buildings. The characteristics of the proposed method are compared with the method that uses the daylight factor. (author)
Survivability of systems under multiple factor impact
Energy Technology Data Exchange (ETDEWEB)
Korczak, Edward [Telecommunications Research Institute, Warsaw (Poland); Levitin, Gregory [Israel Electric Corporation Ltd., Haifa (Israel)]. E-mail: levitin@iec.co.il
2007-02-15
The paper considers vulnerable multi-state series-parallel systems operating under influence of external impacts. Both the external impacts and internal failures affect system survivability, which is determined as the probability of meeting a given demand. The external impacts are characterized by several destructive factors affecting the system or its parts simultaneously. In order to increase the system's survivability a multilevel protection against the destructive factors can be applied to its subsystems. In such systems, the protected subsystems can be destroyed only if all of the levels of their protection are destroyed. The paper presents an algorithm for evaluating the survivability of series-parallel systems with arbitrary configuration of multilevel protection against multiple destructive factor impacts. The algorithm is based on a composition of Boolean and the Universal Generating Function techniques. Illustrative examples are presented.
Multi-pulse phase resetting curve
Krishnan, Giri P.; Bazhenov, Maxim; Pikovsky, Arkady
2013-01-01
In this paper, we introduce and systematically study, in terms of phase response curves (PRC), the effect of a dual pulse excitation on the dynamics of an autonomous oscillator. Specifically, we test the deviations from a linear summation of phase advances from two small perturbations. We derive analytically a correction term, which generally appears for oscillators whose intrinsic dimensionality is greater than one. We demonstrate this effect in case of the Stuart-Landau model, and also in v...
Delamination Analysis Of Composite Curved Bars
Ko, William L.; Jackson, Raymond H.
1990-01-01
Classical anisotropic elasticity theory used to construct "multilayer" composite semicircular curved bar subjected to end forces and end moments. Radial location and intensity of open-mode delamination stress calculated and compared with results obtained from anisotropic continuum theory and from finite element method. Multilayer theory gave more accurate predictions of location and intensity of open-mode delamination stress. Currently being applied to predict open-mode delamination stress concentrations in horse-shoe-shaped composite test coupons.
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.1-3 In this paper I give three examples in which my students use popular curve-fitting software and adjust the theoretical model to account for, and even exploit, the presence of systematic errors in measured data.
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.
Random Matrix Theory and Elliptic Curves
2014-11-24
lecture on random matrix models for elliptic curves at the combined meeting of the Australian and New Zealand mathematical societies Melbourne, Australia...organizer). Associated with the Chichely meeting will be a special volume of the Philosophical Transactions of the Royal Society (the world’s oldest...Distribution A: Approved for public release; distribution is unlimited. 5 USE OF SUPPORT 8 • JPK was awarded a Royal Society Wolfson Research Merit
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.
Twisted vector bundles on pointed nodal curves
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
DEFINITION 2.5. Let C → S be an n-pointed nodal curve over a k-scheme S and let ξ be a principal G- bundle on Cgen. A chart (U, η, ) for ξ is called balanced, if for each ... branches is via multiplication with primitive roots of unity which are inverse to each other. ...... Condition (16) implies that A0 is a block matrix of the form.
High accuracy & long timescale light curves
Directory of Open Access Journals (Sweden)
Hodgkin S.
2013-04-01
Full Text Available We present a theoretical analysis of the optical light curves (LCs for short-period high-mass transiting extrasolar planet systems. Our method considers the primary transit, the secondary eclipse, and the overall phase shape of the LC between the occultations. Phase variations arise from (i reflected and thermally emitted light by the planet, (ii the ellipsoidal shape of the star due to the gravitational pull of the planet, and (iii the Doppler shift of the stellar light as the star orbits the center of mass of the system. Our full model of the out-of-eclipse variations contains information about the planetary mass, orbital eccentricity, the orientation of periastron and the planet's albedo. For a range of hypothetical systems we demonstrate that the ellipsoidal variations (ii. can be large enough to be distinguished from the remaining components and that this effect can be used to constrain the planet's mass. As an example we presend KOI-13b (candidate exoplanet system included in the September 2011 Kepler data release. The Kepler light curve shows both primary and secondary eclipses, as well as significant out-of-eclipse light curve variations. We model the relative contributions from (i thermal emission from the companion, (ii planetary reflected light, (iii doppler beaming, and (iv ellipsoidal variations in the host-star arising from the tidal distortion of the host star by its companion. Our analysis, based on the light curve alone, enables us to constrain the mass of the KOI-13.01 companion to be MC = 8.3 ± 1.25 MJ and thus demonstrates that the transiting companion is a planet. The teqnique is useful for current and future space missions such as Kepler and PLATO.
High accuracy & long timescale light curves
Mislis, D.; Hodgkin, S.
2013-04-01
We present a theoretical analysis of the optical light curves (LCs) for short-period high-mass transiting extrasolar planet systems. Our method considers the primary transit, the secondary eclipse, and the overall phase shape of the LC between the occultations. Phase variations arise from (i) reflected and thermally emitted light by the planet, (ii) the ellipsoidal shape of the star due to the gravitational pull of the planet, and (iii) the Doppler shift of the stellar light as the star orbits the center of mass of the system. Our full model of the out-of-eclipse variations contains information about the planetary mass, orbital eccentricity, the orientation of periastron and the planet's albedo. For a range of hypothetical systems we demonstrate that the ellipsoidal variations (ii.) can be large enough to be distinguished from the remaining components and that this effect can be used to constrain the planet's mass. As an example we presend KOI-13b (candidate exoplanet system) included in the September 2011 Kepler data release. The Kepler light curve shows both primary and secondary eclipses, as well as significant out-of-eclipse light curve variations. We model the relative contributions from (i) thermal emission from the companion, (ii) planetary reflected light, (iii) doppler beaming, and (iv) ellipsoidal variations in the host-star arising from the tidal distortion of the host star by its companion. Our analysis, based on the light curve alone, enables us to constrain the mass of the KOI-13.01 companion to be MC = 8.3 ± 1.25 MJ and thus demonstrates that the transiting companion is a planet. The teqnique is useful for current and future space missions such as Kepler and PLATO.
Revisiting the learning curve (once again
Directory of Open Access Journals (Sweden)
Steven eGlautier
2013-12-01
Full Text Available The vast majority of published work in the field of associative learning seeks to test the adequacy of various theoretical accounts of the learning process using average data. Of course, averaging hides important information, but individual departures from the average are usually designated "error" and largely ignored. However, from the perspective of an individual differences approach, this error is the data of interest; and when associative models are applied to individual learning curves the error is substantial. To some extent individual differences can be reasonably understood in terms of parametric variations of the underlying model. Unfortunately, in many cases, the data cannot be accomodated in this way and the applicability of the underlying model can be called into question. Indeed several authors have proposed alternatives to associative models because of the poor fits between data and associative model. In the current paper a novel associative approach to the analysis of individual learning curves is presented. The Memory Environment Cue Array Model (MECAM is described and applied to two human predictive learning datasets. The MECAM is predicated on the assumption that participants do not parse the trial sequences to which they are exposed into independent episodes as is often assumed when learning curves are modelled. Instead, the MECAM assumes that learning and responding on a trial may also be influenced by the events of the previous trial. Incorporating non-local information the MECAM produced better approximations to individual learning curves than did the Rescorla-Wagner Model (RWM suggesting that further exploration of the approach is warranted.
Blood Pressure J-Curve: Current Concepts
Banach, Maciej; Aronow, Wilbert S.
2012-01-01
The blood pressure (BP) J-curve debate started in 1979, and we still cannot definitively answer all the questions. However, available studies of antihypertensive treatment provide strong evidence for J-shaped relationships between both diastolic and systolic BP and main outcomes in the general population of hypertensive patients, as well as in high-risk populations, including subjects with coronary artery disease, diabetes mellitus, left ventricular hypertrophy, and elderly patients. However,...
Prognostic and survival analysis of presbyopia: The healthy twin study
Lira, Adiyani; Sung, Joohon
2015-12-01
Presbyopia, a vision condition in which the eye loses its flexibility to focus on near objects, is part of ageing process which mostly perceptible in the early or mid 40s. It is well known that age is its major risk factor, while sex, alcohol, poor nutrition, ocular and systemic diseases are known as common risk factors. However, many other variables might influence the prognosis. Therefore in this paper we developed a prognostic model to estimate survival from presbyopia. 1645 participants which part of the Healthy Twin Study, a prospective cohort study that has recruited Korean adult twins and their family members based on a nation-wide registry at public health agencies since 2005, were collected and analyzed by univariate analysis as well as Cox proportional hazard model to reveal the prognostic factors for presbyopia while survival curves were calculated by Kaplan-Meier method. Besides age, sex, diabetes, and myopia; the proposed model shows that education level (especially engineering program) also contribute to the occurrence of presbyopia as well. Generally, at 47 years old, the chance of getting presbyopia becomes higher with the survival probability is less than 50%. Furthermore, our study shows that by stratifying the survival curve, MZ has shorter survival with average onset time about 45.8 compare to DZ and siblings with 47.5 years old. By providing factors that have more effects and mainly associate with presbyopia, we expect that we could help to design an intervention to control or delay its onset time.
The approximation of generalized Log-aesthetic curves using Quintic Bezier curves
Albayari, Diya' J.; Gobithaasan, R. U.; Miura, Kenjiro T.
2017-09-01
Generalized Log Aesthetic Curve segments (GLAC) are aesthetic curves that have monotonic curvature profile and hence they are considered fair. In the field of Computer-Aided Design (CAD), there exists a demand to construct fair curves for various design intent. However, we cannot implement GLAC in CAD system partly due to its transcendental form. A viable solution is to approximate GLACs using a quintic polynomial curve in the form of Bezier using curvature error measure. The problem of this approach is that it requires a formidable size of computations due to arc length reparametrization. In this paper, we introduce a new method of calculating curvature error measure using natural spline interpolation function to minimize computation effort while preserving the accuracy. The final section shows numerical examples depicting the proposed approximation of two types of the GLAC, which clearly indicate the efficiency of proposed method.
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.
Automating Recession Curve Displacement Recharge Estimation.
Smith, Brennan; Schwartz, Stuart
2017-01-01
Recharge estimation is an important and challenging element of groundwater management and resource sustainability. Many recharge estimation methods have been developed with varying data requirements, applicable to different spatial and temporal scales. The variability and inherent uncertainty in recharge estimation motivates the recommended use of multiple methods to estimate and bound regional recharge estimates. Despite the inherent limitations of using daily gauged streamflow, recession curve displacement methods provide a convenient first-order estimate as part of a multimethod hierarchical approach to estimate watershed-scale annual recharge. The implementation of recession curve displacement recharge estimation in the United States Geologic Survey (USGS) RORA program relies on the subjective, operator-specific selection of baseflow recession events to estimate a gauge-specific recession index. This paper presents a parametric algorithm that objectively automates this tedious, subjective process, parameterizing and automating the implementation of recession curve displacement. Results using the algorithm reproduce regional estimates of groundwater recharge from the USGS Appalachian Valley and Piedmont Regional Aquifer-System Analysis, with an average absolute error of less than 2%. The algorithm facilitates consistent, completely automated estimation of annual recharge that complements more rigorous data-intensive techniques for recharge estimation. © 2016, National Ground Water Association.
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.
Dose Effects of Ion Beam Exposure on Deinococcus Radiodurans: Survival and Dose Response
Song, Dao-jun; Wu, Li-fang; Wu, Li-jun; Yu, Zeng-liang
2001-02-01
To explore the survival and dose response of organism for different radiation sources is of great importance in the research of radiobiology. In this study, the survival-dose response of Deinococcus radiodurans (E.coli, as the control) for ultra-violet (UV), γ-rays radiation and ion beam exposure was investigated. The shoulder type of survival curves were found for both UV and γ-ray ionizing radiation, but the saddle type of survival curves were shown for H+, N+(20keV and 30keV) and Ar+ beam exposure. This dose effect of the survival initially decreased with the increase in dose and then increased in the high dose range and finally decreased again in the higher dose range. Our experimental results suggest that D. radiodurans, which is considerably radio-resistant to UV and x-ray and γ-ray ionizing radiation, do not resist ion beam exposure.
Directory of Open Access Journals (Sweden)
D. SCHIAVONE
1974-06-01
Full Text Available A method is described to transform a transverse differential sounding curve to the form of a Schlumberger sounding curve. Starting from the general expression which relates the transverse differential apparent resistivity to the Schlumberger apparent resistivity, it is possible, with some approximations, to derive an easy numerical procedure in order to carry out the transformation. Some considerations are given about the applicability of the method.
Simonsohn, Uri; Simmons, Joseph P; Nelson, Leif D
2015-12-01
When studies examine true effects, they generate right-skewed p-curves, distributions of statistically significant results with more low (.01 s) than high (.04 s) p values. What else can cause a right-skewed p-curve? First, we consider the possibility that researchers report only the smallest significant p value (as conjectured by Ulrich & Miller, 2015), concluding that it is a very uncommon problem. We then consider more common problems, including (a) p-curvers selecting the wrong p values, (b) fake data, (c) honest errors, and (d) ambitiously p-hacked (beyond p < .05) results. We evaluate the impact of these common problems on the validity of p-curve analysis, and provide practical solutions that substantially increase its robustness. (c) 2015 APA, all rights reserved).
Nonlinear Dynamic of Curved Railway Tracks in Three-Dimensional Space
Liu, X.; Ngamkhanong, C.; Kaewunruen, S.
2017-12-01
On curved tracks, high-pitch noise pollution can often be a considerable concern of rail asset owners, commuters, and people living or working along the rail corridor. Inevitably, wheel/rail interface can cause a traveling source of sound and vibration, which spread over a long distance of rail network. The sound and vibration can be in various forms and spectra. The undesirable sound and vibration on curves is often called ‘noise,’ includes flanging and squealing noises. This paper focuses on the squeal noise phenomena on curved tracks located in urban environments. It highlights the effect of curve radii on lateral track dynamics. It is important to note that rail freight curve noises, especially for curve squeals, can be observed almost everywhere and every type of track structures. The most pressing noise appears at sharper curved tracks where excessive lateral wheel/rail dynamics resonate with falling friction states, generating a tonal noise problem, so-call ‘squeal’. Many researchers have carried out measurements and simulations to understand the actual root causes of the squeal noise. Most researchers believe that wheel resonance over falling friction is the main cause, whilst a few others think that dynamic mode coupling of wheel and rail may also cause the squeal. Therefore, this paper is devoted to systems thinking the approach and dynamic assessment in resolving railway curve noise problems. The simulations of railway tracks with different curve radii will be carried out to develop state-of-the-art understanding into lateral track dynamics, including rail dynamics, cant dynamics, gauge dynamics and overall track responses.
Variation of curve number with storm depth
Banasik, K.; Hejduk, L.
2012-04-01
The NRCS Curve Number (known also as SCS-CN) method is well known as a tool in predicting flood runoff depth from small ungauged catchment. The traditional way of determination the CNs, based on soil characteristics, land use and hydrological conditions, seemed to have tendency to overpredict the floods in some cases. Over 30 year rainfall-runoff data, collected in two small (A=23.4 & 82.4 km2), lowland, agricultural catchments in Center of Poland (Banasik & Woodward 2010), were used to determine runoff Curve Number and to check a tendency of changing. The observed CN declines with increasing storm size, which according recent views of Hawkins (1993) could be classified as a standard response of watershed. The analysis concluded, that using CN value according to the procedure described in USDA-SCS Handbook one receives representative value for estimating storm runoff from high rainfall depths in the analyzes catchments. This has been confirmed by applying "asymptotic approach" for estimating the watershed curve number from the rainfall-runoff data. Furthermore, the analysis indicated that CN, estimated from mean retention parameter S of recorded events with rainfall depth higher than initial abstraction, is also approaching the theoretical CN. The observed CN, ranging from 59.8 to 97.1 and from 52.3 to 95.5, in the smaller and the larger catchment respectively, declines with increasing storm size, which has been classified as a standard response of watershed. The investigation demonstrated also changeability of the CN during a year, with much lower values during the vegetation season. Banasik K. & D.E. Woodward (2010). "Empirical determination of curve number for a small agricultural watrshed in Poland". 2nd Joint Federal Interagency Conference, Las Vegas, NV, June 27 - July 1, 2010 (http://acwi.gov/sos/pubs/2ndJFIC/Contents/10E_Banasik_ 28_02_10. pdf). Hawkins R. H. (1993). "Asymptotic determination of curve numbers from data". Journal of Irrigation and Drainage
Curved spiral antennas for underwater biological applications
Llamas, Ruben
We developed curved spiral antennas for use in underwater (freshwater) communications. Specifically, these antennas will be integrated in so-called mussel backpacks. Backpacks are compact electronics that incorporate sensors and a small radio that operate around 300 MHz. Researchers attach these backpacks in their freshwater mussel related research. The antennas must be small, lightweight, and form-fit the mussel. Additionally, since the mussel orientation is unknown, the antennas must have broad radiation patterns. Further, the electromagnetic environment changes significantly as the mussels burrow into the river bottom. Broadband antennas, such a spiral antennas, will perform better in this instance. While spiral antennas are well established, there has been little work on their performance in freshwater. Additionally, there has been some work on curved spiral antennas, but this work focused on curving in one dimension, namely curving around a cylinder. In this thesis we develop spiral antennas that curve in two dimensions in order to conform the contour of a mussel's shell. Our research has three components, namely (a) an investigation of the relevant theoretical underpinning of spiral antennas, (b) extensive computer simulations using state-of-the art computational electromagnetics (CEM) simulation software, and (c) experimental validation. The experimental validation was performed in a large tank in a laboratory setting. We also validated some designs in a pool (~300,000 liters of water and ~410 squared-meter dive pool) with the aid of a certified diver. To use CEM software and perform successful antenna-related experiments require careful attention to many details. The mathematical description of radiation from an antenna, antenna input impedance and so on, is inherently complex. Engineers often make simplifying assumptions such as assuming no reflections, or an isotropic propagation environment, or operation in the antenna far field, and so on. This makes
2010-01-01
... 7 Agriculture 2 2010-01-01 2010-01-01 false Curve for obtaining Operating Characteristic (OC) curve information for skip lot sampling and inspection. 42.142 Section 42.142 Agriculture Regulations of... CONDITION OF FOOD CONTAINERS Miscellaneous § 42.142 Curve for obtaining Operating Characteristic (OC) curve...
DEFF Research Database (Denmark)
Rhodes, Andrew; Evans, Laura E; Alhazzani, Waleed
2017-01-01
OBJECTIVE: To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012". DESIGN: A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings......, and to formulate recommendations as strong or weak, or best practice statement when applicable. RESULTS: The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations...... of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality....
DEFF Research Database (Denmark)
Rhodes, Andrew; Evans, Laura E; Alhazzani, Waleed
2017-01-01
OBJECTIVE: To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012." DESIGN: A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings......, and to formulate recommendations as strong or weak, or best practice statement when applicable. RESULTS: The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations...... of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality....
Department of Homeland Security — Generating Units are any combination of physically connected generators, reactors, boilers, combustion turbines, and other prime movers operated together to produce...
Magnetic insulation of electron flow in curved transmission lines
Energy Technology Data Exchange (ETDEWEB)
Geary, J. [Berkeley Research Associates, Springfield, VA (United States); Grossmann, J. [Naval Research Lab., Washington, DC (United States); Swanekamp, S. [Science Applications International Corp., McLean, VA (United States)
1994-12-31
Magnetically insulated transmission lines with curved sections are often used to transport electrical power in pulsed power generators. These sections can have substantial current losses, which are difficult to model accurately with circuit codes. The authors study the electron flow in curved transmission lines with the particle-in-cell code ISIS. ISIS is formulated using nonorthogonal boundary-fitted coordinates that allow the computational mesh to conform to the conductors. The authors examine a triplate transmission line with a 90{degree} degree bend. Two dimensional simulations with and without the bend show that the critical current for magnetic insulation agrees with the predictions from Brillouin flow within a constant factor of 1.6. They also find that the impedance of an electron beam diode decreases when the diode is attached to a transmission line with a bend compared to when the same diode is attached to a straight transmission line. This appears to result from additional power reflection off the bend in the transmission line and from changes in the vacuum electron flow launched in the bend and the diode. They will also examine the transition from a coaxial to a triplate transmission line.
The experience curve, option value, and the energy paradox
Energy Technology Data Exchange (ETDEWEB)
Ansar, Jasmin [Environmental Policy, Pacific Gas and Electric Company, 77 Beale Street, San Francisco, CA 94106 (United States)]|[Mills College, Oakland, CA 94613 (United States); Sparks, Roger [Mills College, Oakland, CA 94613 (United States)
2009-03-15
This paper develops a model to explain the 'energy paradox,' the inclination of households and firms to require very high internal rates of return in order to make energy-saving investments. The model abstracts from many features of such investments to focus on their irreversibility, the uncertainty of their future payoff streams, and the investor's anticipation of future technological advance. In this setting, the decision to invest in energy-saving technology can be delayed, providing option value. In addition, delay allows the potential investor to cash in on future experience-curve effects: With the passage of time, firms gain practical knowledge in producing and installing the energy-saving technology, enabling them to reduce the technology's up-front cost per unit of energy saved. We incorporate these fundamentals into a stochastic model where the investment's discounted benefits follow geometric Brownian motion. To demonstrate the model's capabilities, we generate simulation results for photovoltaic systems that highlight the experience-curve effect as a fundamental reason why households and firms delay making energy-saving investments until internal rates of return exceed values of 50% and higher, consistent with observations in the economics literature. We also explore altruistic motivations for energy conservation and the model's implications for both 'additionality' and the design of energy-conservation policy. (author)
Greenhouse gas emission curves for advanced biofuel supply chains
Daioglou, Vassilis; Doelman, Jonathan C.; Stehfest, Elke; Müller, Christoph; Wicke, Birka; Faaij, Andre; van Vuuren, Detlef P.
2017-12-01
Most climate change mitigation scenarios that are consistent with the 1.5-2 °C target rely on a large-scale contribution from biomass, including advanced (second-generation) biofuels. However, land-based biofuel production has been associated with substantial land-use change emissions. Previous studies show a wide range of emission factors, often hiding the influence of spatial heterogeneity. Here we introduce a spatially explicit method for assessing the supply of advanced biofuels at different emission factors and present the results as emission curves. Dedicated crops grown on grasslands, savannahs and abandoned agricultural lands could provide 30 EJBiofuel yr-1 with emission factors less than 40 kg of CO2-equivalent (CO2e) emissions per GJBiofuel (for an 85-year time horizon). This increases to 100 EJBiofuel yr-1 for emission factors less than 60 kgCO2e GJBiofuel-1. While these results are uncertain and depend on model assumptions (including time horizon, spatial resolution, technology assumptions and so on), emission curves improve our understanding of the relationship between biofuel supply and its potential contribution to climate change mitigation while accounting for spatial heterogeneity.
Fast infrared maritime target detection: Binarization via histogram curve transformation
Wang, Bin; Dong, Lili; Zhao, Ming; Xu, Wenhai
2017-06-01
To improve the accuracy and efficiency of infrared maritime target detection under different environmental conditions and for different kinds of targets, we proposed a novel self-adaptive binarization algorithm which is based on the histogram curve transformation. The main contribution was a rapid and robust method for detecting infrared maritime targets that have positive local contrasts. This method has low computational complexity and high detection accuracy under a variety of conditions and enhances the accuracy and speed of single-frame detection for infrared maritime distressed targets. The proposed histogram rightwards cyclic shift binarization (HRCSB) first transforms the histogram curve (HC) according to a self-adaptive gray level transformation equation. Then, the background subtraction based on Gaussian filtering can be used to generate an enhanced image. Finally, the final HC can be extracted from this enhanced image. After a cyclic shift of the final HC, the average gray level of the shifted HC can reveal an effective threshold for detecting targets from the enhanced image. Experimental results show that, compared with four existing algorithms, the proposed HRCSB can successfully detect targets under a variety of conditions while keeping a low false alarm rate and a low computational complexity. Thus, the proposed HRCSB algorithm has potential for excellent applicability.
Füllgrabe, Jens; Heldring, Nina; Hermanson, Ola; Joseph, Bertrand
2014-01-01
Modifications of histones, the chief protein components of the chromatin, have emerged as critical regulators of life and death. While the “apoptotic histone code” came to light a few years ago, accumulating evidence indicates that autophagy, a cell survival pathway, is also heavily regulated by histone-modifying proteins. In this review we describe the emerging “autophagic histone code” and the role of histone modifications in the cellular life vs. death decision. PMID:24429873
2016-06-01
experiment mode also enables users to set their own design of experiment by manipulating an editable CSV file. The second one is a real-time mode that...renders a 3D virtual environment of a restricted battlefield where the survivability movements of an artillery company are visualized . This mode...provides detailed visualization of the simulation and enables future experimental uses of the simulation as a training tool. 14. SUBJECT TERMS
SURVIVAL ANALYSIS AND LENGTH-BIASED SAMPLING
Directory of Open Access Journals (Sweden)
Masoud Asgharian
2010-12-01
Full Text Available When survival data are colleted as part of a prevalent cohort study, the recruited cases have already experienced their initiating event. These prevalent cases are then followed for a fixed period of time at the end of which the subjects will either have failed or have been censored. When interests lies in estimating the survival distribution, from onset, of subjects with the disease, one must take into account that the survival times of the cases in a prevalent cohort study are left truncated. When it is possible to assume that there has not been any epidemic of the disease over the past period of time that covers the onset times of the subjects, one may assume that the underlying incidence process that generates the initiating event times is a stationary Poisson process. Under such assumption, the survival times of the recruited subjects are called “lengthbiased”. I discuss the challenges one is faced with in analyzing these type of data. To address the theoretical aspects of the work, I present asymptotic results for the NPMLE of the length-biased as well as the unbiased survival distribution. I also discuss estimating the unbiased survival function using only the follow-up time. This addresses the case that the onset times are either unknown or known with uncertainty. Some of our most recent work and open questions will be presented. These include some aspects of analysis of covariates, strong approximation, functional LIL and density estimation under length-biased sampling with right censoring. The results will be illustrated with survival data from patients with dementia, collected as part of the Canadian Study of Health and Aging (CSHA.
Survival after dementia diagnosis in five racial/ethnic groups.
Mayeda, Elizabeth R; Glymour, M Maria; Quesenberry, Charles P; Johnson, Julene K; Pérez-Stable, Eliseo J; Whitmer, Rachel A
2017-07-01
Information on anticipated survival time after dementia diagnosis among racially/ethnically diverse patients is needed to plan for care and evaluate disparities. Dementia-free health care members aged ≥64 years were followed (1/1/2000-12/31/2013) for dementia diagnosis and subsequent survival (n = 23,032 Asian American; n = 18,778 African American; n = 21,000 Latino; n = 4543 American Indian/Alaska Native; n = 206,490 white). Kaplan-Meier curves were estimated for survival after dementia diagnosis by race/ethnicity. We contrasted mortality patterns among people with versus without dementia using Cox proportional hazards models. After dementia diagnosis (n = 59,494), whites had shortest median survival (3.1 years), followed by American Indian/Alaska Natives (3.4 years), African Americans (3.7 years), Latinos (4.1 years), and Asian Americans (4.4 years). Longer postdiagnosis survival among racial/ethnic minorities compared with whites persisted after adjustment for comorbidities. Racial/ethnic mortality inequalities among dementia patients mostly paralleled mortality inequalities among people without dementia. Survival after dementia diagnosis differs by race/ethnicity, with shortest survival among whites and longest among Asian Americans. Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.
Radioprotective effect of chlorpromazine on the survival of mice
Energy Technology Data Exchange (ETDEWEB)
Kale, R.K.; Chandra, D. [Jawaharlal Nehru Univ., New Dalhi (India). School of Life Sciences
2000-05-01
Importance of radiomodification by phenothiazines like chlorpromazine (CPZ) in improving the radiation therapy of cancer has recently been suggested. To achieve a greater application and wide acceptance, the radioprotective potential of CPZ is examined in terms of survival of animals. Swiss albino mice were administered CPZ intraperitonially and irradiated with different doses of g-rays at the dose rate of 1.38 Gy/min. The death profile, median survival time and temporal survival pattern was determined. Administration of CPZ prior to irradiation resulted in decrease of death rate, enhancement of median survival time and significant delay in early decline in survival of animals. Radioprotective ability of CPZ was clearly visible from the temporal survival pattern. CPZ shifted the survival curves towards the right side. The protective action of CPZ against radiation effect was reversed in presence of ferrous (Fe2+) ions and on the other hand, the protective effect of CPZ was enhanced considerably in presence of ferric (Fe3+) ions. CPZ provided considerable protection to mice irradiated with g-rays. Radioprotective effectiveness of CPZ could be attributed to multiple mechanisms of action. The enhanced radioprotection in presence of Fe3+ ions and radiosensitization in presence of Fe2+ ions by CPZ were an important observations and probably be ascribed to the altered redox activity of Fe3+ and Fe2+ ions by CPZ or vice-versa. Since, CPZ is in regular chemical use, these findings might be significant for the improvement radiation therapy of cancer. (author)
Continuous daily hydrograph simulation using duration curves of a precipitation index
CSIR Research Space (South Africa)
Smakhtin, VY
2000-04-01
Full Text Available The paper describes a parsimonious approach for generating continuous daily stream-flow time-series from observed daily rainfall data in a catchment. The key characteristic in the method is a duration curve. It is used to convert the daily rainfall...
Survival analysis models and applications
Liu, Xian
2012-01-01
Survival analysis concerns sequential occurrences of events governed by probabilistic laws. Recent decades have witnessed many applications of survival analysis in various disciplines. This book introduces both classic survival models and theories along with newly developed techniques. Readers will learn how to perform analysis of survival data by following numerous empirical illustrations in SAS. Survival Analysis: Models and Applications: Presents basic techniques before leading onto some of the most advanced topics in survival analysis.Assumes only a minimal knowledge of SAS whilst enablin
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.
Kim, Ki Hyun; Park, Sang Woo; Chang, Il Soo; Yim, Younghee
2016-09-21
To evaluate the dwell time and actual survival rates of peripherally inserted central catheter (PICC) placements after balloon angioplasty in patients with unexpected central venous obstructions. Data were obtained on all PICC insertions performed in a tertiary care hospital from August 2008 to December 2013. Thirty-five PICCs attempted after balloon angioplasty in 25 patients (15 male and 10 female patients; mean age, 63 years). Fisher's exact test was used to test for differences in reasons for catheter removal between the groups of patients with stenosis or obstructions. Survival curves for PICC dwell time of all patients, stenosis group, and obstruction group were generated separately using Kaplan-Meier survival analysis and compared with log-rank tests. There were a total 21 obstructions and 14 stenoses. The overall technical success rate of PICC placement after balloon angioplasty was 94% (33 of 35 procedures). The PICC dwell time was determined for 27 PICCs and ranged from 4 to 165 days (mean, 39.6 days). Among all PICCs, 16 were removed early, resulting in an actual survival rate of 40.7% (11 of 27 PICCs). There were no significant differences in reasons for catheter removal between the stenosis and obstruction groups (p = 0.24). The dwell times for both groups were not significantly different by Kaplan-Meier analysis (p = 0.54). PICC placement after balloon angioplasty is a good treatment option for patients with unexpected central venous lesions, and offers high technical success rates. The actual survival rate was relatively lower (40.7%) than that from previous studies.
Kramer, Linda W
2010-01-01
Generational diversity has proven challenges for nurse leaders, and generational values may influence ideas about work and career planning. This article discusses generational gaps, influencing factors and support, and the various generational groups present in today's workplace as well as the consequences of need addressing these issues. The article ends with a discussion of possible solutions.
Comparison of growth curve models in partridge.
Sariyel, V; Aygun, A; Keskin, I
2017-06-01
This study was conducted in order to determine the goodness of fit of Brody, Gompertz, Logistic, and von Bertalanffy growth curve models in partridge (Alectoris chukar). The growth curve parameters A (upper asymptote or mature weight parameter), B (scale parameter related to initial weight), and K (instantaneous growth rate parameter) were determined as 623.4, 1.05, and 0.075 for females and 723.8, 1.06, and 0.073 for males in the Brody model, respectively, 472.9, 3.47, and 0.207 for females and 565.3, 3.59, and 0.192 for males in the Gompertz model, respectively, 440.2, 12.89, and 0.332 for females and 517.0, 14.13, and 0.319 for males in the Logistic model, respectively, and 498.9, 0.77, and 0.164 for females and 608.8, 0.79, and 0.150 for males in the von Bertalanffy model, respectively. While determining which growth curve model presented the better fit, the coefficient of determination (R2), adjusted the coefficient of determination (adj.R2), mean square predicted error (MSPE), Durbin-Watson value, correlation between estimated live weight and residual values (RESC), Akaike's information criteria (AIC), and Bayesian information criterion (BIC) were used. As a consequence of the study, it was determined that the Gompertz model yields a better fit to the data for the partridge, as its coefficient of determination and adjusted coefficient of determination are high, its values of MSPE, RESC, AIC, BIC are low and there is not an autocorrelation between the residual values. As a result, the Gompertz model presented a better fit with the partridge data. © 2017 Poultry Science Association Inc.
Hip Fracture Surgery and Survival in Centenarians.
Mazzola, Paolo; Rea, Federico; Merlino, Luca; Bellelli, Giuseppe; Dubner, Lauren; Corrao, Giovanni; Pasinetti, Giulio M; Annoni, Giorgio
2016-11-01
Hip fracture (HF) is increasingly frequent with advancing age. Studies describing the HF incidence rate and survival after surgery in centenarians are scanty. To fill this gap, we performed a large population-based investigation on Lombardy centenarians (Italy). Retrospective observational cohort study based on information from the Healthcare Utilization Database. Among the cohort of 7,830 residents that reached 100 years of age between 2004 and 2011, incidence rate of HF was calculated. Two hundred fifty-nine patients were discharged alive from a hospital after HF and surgical repair (HF cohort). For each HF cohort member, a control was randomly selected from the initial cohort to be matched for gender and date of birth, and who did not experience HF from the date of their hundredth birthday until the date of hospital discharge of the corresponding HF cohort member. The survival curves and the hazard functions of HF and control cohort were calculated within 2 years. Over a mean follow-up of 1.85 years, HF incidence rate was 23.1 per 1,000 centenarians per year. Survival probability was significantly lower in HF cohort than in control cohort (31.5 vs 48.1%, p < .001). Hazard functions showed an increased risk of death in HF cohort than in control cohort, especially in the 3 months after surgery. Survival analysis exhibited an excess mortality in the first 3 months among HF cohort members, but not beyond this period. Every effort to counteract HF is warranted, including prevention of falls and high quality of care, especially in the early postsurgical time. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Text line Segmentation of Curved Document Images
Directory of Open Access Journals (Sweden)
Anusree.M
2014-05-01
Full Text Available Document image analysis has been widely used in historical and heritage studies, education and digital library. Document image analytical techniques are mainly used for improving the human readability and the OCR quality of the document. During the digitization, camera captured images contain warped document due perspective and geometric distortions. The main difficulty is text line detection in the document. Many algorithms had been proposed to address the problem of printed document text line detection, but they failed to extract text lines in curved document. This paper describes a segmentation technique that detects the curled text line in camera captured document images.
INFLUENCE OF MOVING LOADS ON CURVED BRIDGES
Thamer A. Z*, Jabbbar S. A
2016-01-01
The behavior of a curved slab bridge decks with uniform thickness under moving load is investigated in this study. Three radii of curvature "R" are used (25, 50 and 75m) along with the straight bridge, R = ∞. The decks are simply supported or clamped along the radial edges and free at the circular edges. The AASHTO[1] standard axle load of the truck H20-44 is used and assumed to move in three track positions on the bridge. The finite element method is employed for the analysis and the ANSYS 5...
Elliptic Tales Curves, Counting, and Number Theory
Ash, Avner
2012-01-01
Elliptic Tales describes the latest developments in number theory by looking at one of the most exciting unsolved problems in contemporary mathematics--the Birch and Swinnerton-Dyer Conjecture. The Clay Mathematics Institute is offering a prize of 1 million to anyone who can discover a general solution to the problem. In this book, Avner Ash and Robert Gross guide readers through the mathematics they need to understand this captivating problem. The key to the conjecture lies in elliptic curves, which are cubic equations in two variables. These equations may appear simple, yet they arise from
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
Task 4 Improvised Nuclear Device Response Curves
Energy Technology Data Exchange (ETDEWEB)
Alai, Maureen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Neuscamman, Stephanie [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2016-05-31
LLNL performed fallout and nuclear blast modeling for the 60 cities using the NARAC modeling system and predominant weather patterns determined in a previous Task 4 effort. LLNL performed model simulations and analyses to identify and provide response curves (expressed as two-dimensional contours) for radioactive fallout deposition, transport, population, and blast overpressure as a function of yield, weather, location and time. These contours can then be further combined and correlated with infrastructure and population databases to estimate city specific effects on KPFs such as impacted infrastructure and casualty rates.
New symmetry of intended curved reaches
Directory of Open Access Journals (Sweden)
Torres Elizabeth B
2010-04-01
Full Text Available Abstract Background Movement regularities are inherently present in automated goal-directed motions of the primate's arm system. They can provide important signatures of intentional behaviours driven by sensory-motor strategies, but it remains unknown if during motor learning new regularities can be uncovered despite high variability in the temporal dynamics of the hand motions. Methods We investigated the conservation and violation of new movement regularity obtained from the hand motions traced by two untrained monkeys as they learned to reach outwardly towards spatial targets while avoiding obstacles in the dark. The regularity pertains to the transformation from postural to hand paths that aim at visual goals. Results In length-minimizing curves the area enclosed between the Euclidean straight line and the curve up to its point of maximum curvature is 1/2 of the total area. Similar trend is found if one examines the perimeter. This new movement regularity remained robust to striking changes in arm dynamics that gave rise to changes in the speed of the reach, to changes in the hand path curvature, and to changes in the arm's postural paths. The area and perimeter ratios characterizing the regularity co-varied across repeats of randomly presented targets whenever the transformation from posture to hand paths was compliant with the intended goals. To interpret this conservation and the cases in which the regularity was violated and recovered, we provide a geometric model that characterizes arm-to-hand and hand-to-arm motion paths as length minimizing curves (geodesics in a non-Euclidean space. Whenever the transformation from one space to the other is distance-metric preserving (isometric the two symmetric ratios co-vary. Otherwise, the symmetric ratios and their co-variation are violated. As predicted by the model we found empirical evidence for the violation of this movement regularity whenever the intended goals mismatched the actions. This
Membrane Buckling Induced by Curved Filaments
Lenz, Martin; Crow, Daniel J. G.; Joanny, Jean-François
2009-07-01
We present a novel buckling instability relevant to membrane budding in eukaryotic cells. In this mechanism, curved filaments bind to a lipid bilayer without changing its intrinsic curvature. As more and more filaments adsorb, newly added ones are more and more strained, which destabilizes the flat membrane. We perform a linear stability analysis of filament-dressed membranes and find that the buckling threshold is within reasonable in vivo parameter values. We account for the formation of long tubes previously observed in cells and in purified systems. We study strongly deformed dressed membranes and their bifurcation diagram numerically. Our mechanism could be validated by a simple experiment.
Cracks in Sheets Draped on Curved Surfaces
Mitchell, Noah P.; Koning, Vinzenz; Vitelli, Vincenzo; Irvine, William T. M.
Conforming materials to surfaces with Gaussian curvature has proven a versatile tool to guide the behavior of mechanical defects such as folds, blisters, scars, and pleats. In this talk, we show how curvature can likewise be used to control material failure. In our experiments, thin elastic sheets are confined on curved geometries that stimulate or suppress the growth of cracks, and steer or arrest their propagation. By redistributing stresses in a sheet, curvature provides a geometric tool for protecting certain regions and guiding crack patterns. A simple model captures crack behavior at the onset of propagation, while a 2D phase-field model successfully captures the crack's full phenomenology.
Wave regularity in curve integrable spacetimes
Sanchez, Yafet Sanchez
2015-01-01
The idea of defining a gravitational singularity as an obstruction to the dynamical evolution of a test field (described by a PDE) rather than the dynamical evolution of a particle (described by a geodesics) is explored. In particular, the concept of wave regularity is introduced which serves to show that the classical singularities in curve integrable spacetimes do not interrupt the well-posedness of the wave equation. The techniques used also provide arguments that can be extended to establish when a classically singular spacetime remains singular in a semi-classical picture.
Operators and higher genus mirror curves
Energy Technology Data Exchange (ETDEWEB)
Codesido, Santiago [Département de Physique Théorique et section de Mathématiques,Université de Genève,Genève, CH-1211 (Switzerland); Gu, Jie [Laboratoire de Physique Théorique de l’École Normale Supérieure,CNRS, PSL Research University,Sorbonne Universités, UPMC, 75005 Paris (France); Mariño, Marcos [Département de Physique Théorique et section de Mathématiques,Université de Genève,Genève, CH-1211 (Switzerland)
2017-02-17
We perform further tests of the correspondence between spectral theory and topological strings, focusing on mirror curves of genus greater than one with nontrivial mass parameters. In particular, we analyze the geometry relevant to the SU(3) relativistic Toda lattice, and the resolved ℂ{sup 3}/ℤ{sub 6} orbifold. Furthermore, we give evidence that the correspondence holds for arbitrary values of the mass parameters, where the quantization problem leads to resonant states. We also explore the relation between this correspondence and cluster integrable systems.
Localization of nonlinear excitations in curved waveguides
DEFF Research Database (Denmark)
Gaididei, Yu. B.; Christiansen, Peter Leth; Kevrekidis, P. G.
2005-01-01
Motivated by the examples of a curved waveguide embedded in a photonic crystal and cold atoms moving in a waveguide created by a spatially inhomogeneous electromagnetic field, we examine the effects of geometry in a 'quantum channel' of parabolic form. Starting with the linear case we derive exact...... as well as approximate expressions for the eigenvalues and eigenfunctions of the linear problem. We then proceed to the nonlinear setting and its stationary states in a number of limiting cases that allow for analytical treatment. The results of our analysis are used as initial conditions in direct...
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...... is computationally fast and provides direct (geometrical) parameter insight as regards the determination of the electron transmission coefficient. We present, as a case study, calculations of the electron conductivity of a helically shaped quantum-wire structure and discuss the influence of the quantum...
Discreteness of Curved Spacetime from GUP
Directory of Open Access Journals (Sweden)
Ahmad Adel Abutaleb
2013-01-01
Full Text Available Diverse theories of quantum gravity expect modifications of the Heisenberg's uncertainty principle near the Planck scale to a so-called Generalized uncertainty principle (GUP. It was shown by some authors that the GUP gives rise to corrections to the Schrodinger , Klein-Gordon, and Dirac equations. By solving the GUP corrected equations, the authors arrived at quantization not only of energy but also of box length, area, and volume. In this paper, we extend the above results to the case of curved spacetime (Schwarzschild metric. We showed that we arrived at the quantization of space by solving Dirac equation with GUP in this metric.
Lossless compression of medical images using Hilbert space-filling curves.
Liang, Jan-Yie; Chen, Chih-Sheng; Huang, Chua-Huang; Liu, Li
2008-04-01
A Hilbert space-filling curve is a curve traversing the 2(n) x 2(n)two-dimensional space and it visits neighboring points consecutively without crossing itself. The application of Hilbert space-filling curves in image processing is to rearrange image pixels in order to enhance pixel locality. A computer program of the Hilbert space-filling curve ordering generated from a tensor product formula is used to rearrange pixels of medical images. We implement four lossless encoding schemes, run-length encoding, LZ77 coding, LZW coding, and Huffman coding, along with the Hilbert space-filling curve ordering. Combination of these encoding schemes are also implemented to study the effectiveness of various compression methods. In addition, differential encoding is employed to medical images to study different format of image representation to the above encoding schemes. In the paper, we report the testing results of compression ratio and performance evaluation. The experiments show that the pre-processing operation of differential encoding followed by the Hilbert space-filling curve ordering and the compression method of LZW coding followed by Huffman coding will give the best compression result.
Dose-Response Curve of Chromosome Aberrations in Human Lymphocytes Induced by Gamma-Rays
Directory of Open Access Journals (Sweden)
Y. Lusiyanti
2013-12-01
Full Text Available Chromosome aberration is a biomarker to predict the level of cell damage caused by exposure to ionizing radiation on human body. Dicentric chromosome is a specific chromosome aberration caused by ionizing radiation and is used as a gold standard biodosimetry of individuals over exposed to ionizing radiation. In radiation accident the dicentric assays has been applied as biological dosimetry to estimate radiation absorbed dose and also to confirm the radiation dose received to radiation workers.The purpose of this study was to generate a dose response curve of chromosome aberration (dicentric in human lymphocyte induced by gamma radiation. Peripheral blood samples from three non smoking healthy volunteers aged between 25-48 years old with informed consent were irradiated with dose between 0.1-4.0 Gy and a control using gamma teletherapy source. The culture procedure was conducted following the IAEA standard procedures with slight modifications. Analysis of dose-response curves used was LQ model Y = a + αD + βD2. The result showed that α and β values of the curve obtained were 0.018 ± 0.006 and 0.013 ± 0.002, respectively. Dose response calibration curve for dicentric chromosome aberrations in human lymphocytes induced by gamma-radiation fitted to linear quadratic model. In order to apply the dose response curve of chromosome aberration disentric for biodosimetry, this standar curve still need to be validated.
Quantitation of collagen fragments and gelatin by deconvolution of polarimetry denaturation curves.
Condell, R A; Sakai, N; Mercado, R T; Larenas, E
1988-09-01
A method for quantitating nicked or shortened molecules (fragments) in pepsinized bovine type I collagen preparations using polarimetry thermal denaturation curves is described. The shortened molecules denature about 4 degrees C lower than intact collagen molecules. The analog output of a polarimeter was digitized and stored on a microcomputer disk. A BASIC program was written which retrieves the specific rotation data from the disk, smooths the data with a boxcar average, and plots the derivative of the denaturation curve. The derivative curve was deconvoluted by fitting three Gaussian curves to the derivative curve using published algorithms. The area of the Gaussian centered at 37 degrees C was proportional to the amount of collagen fragments. A good correlation between the amount of fragments determined by polarimetry and by a trypsin sensitivity assay was observed. The overall precision of the method was about 10% RSD, and the method was repeatable by multiple analysts. Application of the method to reconstituted fibrillar collagen samples showed that more fragments are generated when pepsin digestion time is lengthened. By fitting a fourth Gaussian component to the derivative curve, the method can also be used to determine relative amounts of denatured collagen (helix partially unwound but alpha chains not nicked). The detection limit for denatured collagen is about 20%.
Saeidabadi, Mohammad Sadegh; Nili, Hassan; Dadras, Habibollah; Sharifiyazdi, Hassan; Connolly, Joanne; Valcanis, Mary; Raidal, Shane; Ghorashi, Seyed Ali
2017-06-01
Consumption of poultry products contaminated with Salmonella is one of the major causes of foodborne diseases worldwide and therefore detection and differentiation of Salmonella spp. in poultry is important. In this study, oligonucleotide primers were designed from hemD gene and a PCR followed by high-resolution melt (HRM) curve analysis was developed for rapid differentiation of Salmonella isolates. Amplicons of 228 bp were generated from 16 different Salmonella reference strains and from 65 clinical field isolates mainly from poultry farms. HRM curve analysis of the amplicons differentiated Salmonella isolates and analysis of the nucleotide sequence of the amplicons from selected isolates revealed that each melting curve profile was related to a unique DNA sequence. The relationship between reference strains and tested specimens was also evaluated using a mathematical model without visual interpretation of HRM curves. In addition, the potential of the PCR-HRM curve analysis was evaluated for genotyping of additional Salmonella isolates from different avian species. The findings indicate that PCR followed by HRM curve analysis provides a rapid and robust technique for genotyping of Salmonella isolates to determine the serovar/serotype.
Can Low-Resolution Airborne Laser Scanning Data Be Used to Model Stream Rating Curves?
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Steve W. Lyon
2015-03-01
Full Text Available This pilot study explores the potential of using low-resolution (0.2 points/m2 airborne laser scanning (ALS-derived elevation data to model stream rating curves. Rating curves, which allow the functional translation of stream water depth into discharge, making them integral to water resource monitoring efforts, were modeled using a physics-based approach that captures basic geometric measurements to establish flow resistance due to implicit channel roughness. We tested synthetically thinned high-resolution (more than 2 points/m2 ALS data as a proxy for low-resolution data at a point density equivalent to that obtained within most national-scale ALS strategies. Our results show that the errors incurred due to the effect of low-resolution versus high-resolution ALS data were less than those due to flow measurement and empirical rating curve fitting uncertainties. As such, although there likely are scale and technical limitations to consider, it is theoretically possible to generate rating curves in a river network from ALS data of the resolution anticipated within national-scale ALS schemes (at least for rivers with relatively simple geometries. This is promising, since generating rating curves from ALS scans would greatly enhance our ability to monitor streamflow by simplifying the overall effort required.
Can low-resolution airborne laser scanning data be used to model stream rating curves?
Lyon, Steve; Nathanson, Marcus; Lam, Norris; Dahlke, Helen; Rutzinger, Martin; Kean, Jason W.; Laudon, Hjalmar
2015-01-01
This pilot study explores the potential of using low-resolution (0.2 points/m2) airborne laser scanning (ALS)-derived elevation data to model stream rating curves. Rating curves, which allow the functional translation of stream water depth into discharge, making them integral to water resource monitoring efforts, were modeled using a physics-based approach that captures basic geometric measurements to establish flow resistance due to implicit channel roughness. We tested synthetically thinned high-resolution (more than 2 points/m2) ALS data as a proxy for low-resolution data at a point density equivalent to that obtained within most national-scale ALS strategies. Our results show that the errors incurred due to the effect of low-resolution versus high-resolution ALS data were less than those due to flow measurement and empirical rating curve fitting uncertainties. As such, although there likely are scale and technical limitations to consider, it is theoretically possible to generate rating curves in a river network from ALS data of the resolution anticipated within national-scale ALS schemes (at least for rivers with relatively simple geometries). This is promising, since generating rating curves from ALS scans would greatly enhance our ability to monitor streamflow by simplifying the overall effort required.
Curves and surfaces in the context of optometry. Part 1: Curves*
Directory of Open Access Journals (Sweden)
W.F. Harris
2005-01-01
Full Text Available This paper introduces the differential geom-etry of curves in Euclidean 3-space, the motiva-tion being the writer’s belief that, despite their fundamental importance, curves are inadequate-ly treated in optometric educational programs. Curvature and torsion are defined along a curve. Two numerical examples are presented. The fundamental theorem of curves is stated. The relationship of the geometry of varifocal lenses and curves known as involutes are discussed. A brief treatment of the theory of contact is given with suggestions of applications in contact between spectacle lenses and frames, contact lenses and corneas (including orthokeratology, intra-ocular lenses and structures in the eye, and spectacle frames and the face.
Survival after blood transfusion
DEFF Research Database (Denmark)
Kamper-Jørgensen, Mads; Ahlgren, Martin; Rostgaard, Klaus
2008-01-01
of transfusion recipients in Denmark and Sweden followed for up to 20 years after their first blood transfusion. Main outcome measure was all-cause mortality. RESULTS: A total of 1,118,261 transfusion recipients were identified, of whom 62.0 percent were aged 65 years or older at the time of their first...... the SMR remained significantly 1.3-fold increased. CONCLUSION: The survival and relative mortality patterns among blood transfusion recipients were characterized with unprecedented detail and precision. Our results are relevant to assessments of the consequences of possible transfusion-transmitted disease...... as well as for cost-benefit estimation of new blood safety interventions....
Energy Technology Data Exchange (ETDEWEB)
Kearny, C.H.
2002-06-24
The purpose of this book is to provide Americans with information and instructions that will significantly increase their chances of surviving a possible nuclear attack. It brings together field-tested instructions that, if followed by a large fraction of Americans during a crisis that preceded an attack, could save millions of lives. The author is convinced that the vulnerability of our country to nuclear threat or attack must be reduced and that the wide dissemination of the information contained in this book would help achieve that objective of our overall defense strategy.
Stoer, Mechthild
1992-01-01
The problem of designing a cost-efficient network that survives the failure of one or more nodes or edges of the network is critical to modern telecommunications engineering. The method developed in this book is designed to solve such problems to optimality. In particular, a cutting plane approach is described, based on polyhedral combinatorics, that is ableto solve real-world problems of this type in short computation time. These results are of interest for practitioners in the area of communication network design. The book is addressed especially to the combinatorial optimization community, but also to those who want to learn polyhedral methods. In addition, interesting new research problemsare formulated.
Focal Conic Flower Textures at Curved Interfaces
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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.
Analysis of the vitreoretinal surgery learning curve.
Martín-Avià, J; Romero-Aroca, P
2017-06-01
To describe intra- and post-operative complications, as well as the evolution of the surgical technique in first 4years of work of a novice retina surgeon, and evaluate minimal learning time required to reduce its complications, deciding which pathologies should still be referred to higher level hospitals, until further experience may be achieved. A study was conducted on patients that had undergone vitreoretinal surgery by a novice surgeon in Tarragona between 23rd October 2007 and 31st December 2011. The primary diagnosis, surgeon learning time, surgical technique, intra-operative and post-operative complications were recorded. A total of 247 surgeries were studied. The percentage of use of 20G and 23G calibres during the time, marks a change towards trans-conjunctival surgery from the ninth trimester (98 surgeries). Surgical complications decreased towards twelfth trimester (130 surgeries) with an increase in the previous months. The shift towards 23G technique around 100 surgeries is interpreted as greater comfort and safety by the surgeon. Increased surgical complications during the following months until its decline around 130 surgeries can be interpreted as an 'overconfidence'. It is arguable that the learning curve is slower than what the surgeon believes. An individual analysis of the complications and surgical outcomes is recommended to ascertain the status of the learning curve. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.
Light Curve Variations of AR Lacertae
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Il-Seong Nha
1991-12-01
Full Text Available Sixteen unitary Light curves of AR Lac in B and V are made at Yonsei University Observatory in the period of 1980-1988. Some overview findings of light variations are made. (1 The light variations outside eclipse follow none of the wave migration patterns reported by previous investigators. (2 Complicated shapes outside eclipse are apparently much reduced in the light curves of 1983-1984. This suggests that, in the future, AR Lac has a chance to attain a normal state with mo complicated interactions. (3 The depths of the primary and the secondary mid-eclipses are changing year-to-year. (4 The K0 star, the larger component, has brightened by 0.m14 V, while the G2 star has shown a fluctuation of about 0.m05 in V. (5 The B-V values at primary mid-eclipse have no correlation with the depth variations. (6 Independently of the increase of maximum brightness, the B-V colors in the non-eclipsed phases changed slightly over the years.
R-curve behavior in ferrite ceramics
Energy Technology Data Exchange (ETDEWEB)
Beauchamp, E.K.; Monroe, S.L.
1990-01-01
The unusual dependence of the fracture mode of ferrite ceramics on the stress intensity factor in the subcritical crack growth regime was used to create flaws with different concentrations of crack-interface bridges. Flaws with numerous bridges were produced by indenting under dry silicone oil, while flaws with essentially no bridges were produced by indenting under water. Plots of log failure stress as a function of log indenter load for the two types of flaws reflect the differences in bridging. Those with extensive bridging showed pronounced R-curve behavior. The curve for those initially devoid of bridges showed no plateau but did show deviations from a {minus}1/3 slope that correspond to those predicted by Bennison and Lawn for this type of flaw. The ferrite studies was 62.4 Fe{sub 2}O{sub 3} 26.6 MnO, 11.2nO, and .04 V{sub 2}O{sub 5}. 10 figs.
Curved Piezoelectric Actuators for Stretching Optical Fibers
Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.
2008-01-01
Assemblies containing curved piezoceramic fiber composite actuators have been invented as means of stretching optical fibers by amounts that depend on applied drive voltages. Piezoceramic fiber composite actuators are conventionally manufactured as sheets or ribbons that are flat and flexible, but can be made curved to obtain load-carrying ability and displacement greater than those obtainable from the flat versions. In the primary embodiment of this invention, piezoceramic fibers are oriented parallel to the direction of longitudinal displacement of the actuators so that application of drive voltage causes the actuator to flatten, producing maximum motion. Actuator motion can be transmitted to the optical fiber by use of hinges and clamp blocks. In the original application of this invention, the optical fiber contains a Bragg grating and the purpose of the controlled stretching of the fiber is to tune the grating as part of a small, lightweight, mode-hop-free, rapidly tunable laser for demodulating strain in Bragg-grating strain-measurement optical fibers attached to structures. The invention could also be used to apply controllable tensile force or displacement to an object other than an optical fiber.
A simple transformation for converting CW-OSL curves to LM-OSL curves
DEFF Research Database (Denmark)
Bulur, E.
2000-01-01
A simple mathematical transformation is introduced to convert from OSL decay curves obtained in the conventional way to those obtained using a linear modulation technique based on a linear increase of the stimulation light intensity during OSL measurement. The validity of the transformation...... was tested by the IR-stimulated luminescence curves from feldspars, recorded using both the conventional and the linear modulation techniques. The transformation was further applied to green-light-stimulated OSL from K and Na feldspars. (C) 2000 Elsevier Science Ltd. All rights reserved....
Components of the Hilbert scheme of space curves on low-degree smooth surfaces
Kleppe, Jan Oddvar; Ottem, John Christian
2015-01-01
We study maximal families W of the Hilbert scheme, H(d, g)sc, of smooth connected space curves whose general curve C lies on a smooth surface S of degree s. We give conditions on C under which W is a generically smooth component of H(d, g)sc and we determine dim W. If s = 4 and W is an irreducible component of H(d, g)sc, then the Picard number of S is at most 2 and we explicitly describe, also for s ≥ 5, non-reduced and generically smooth components in the case Pic(S) is generated by the clas...
Hernández Yáñez, Eduard; Moreno, Fabian Leonardo; Raventós Santamaria, Mercè; Santamaría, N.; Acosta, J.; Pirachican, Oscar; Torres, L.; Ruiz Pardo, Yolanda
2015-01-01
The physical properties of coffee solutions were determined for temperatures close to the freezing point. Rheological behaviour, freezing curve, density, and their relationship between coffee mass fraction and Brix degrees were determined for coffee mass fractions between 5 and 50% (wet basis) in the -6 to 20 degrees C temperature interval. Values of viscosity varied from 1.99 to 1037 mPa center dot s and values of density from 1000 to 1236 kg center dot m(-3). The freezing curve was generate...
The difference between the Weil height and the canonical height on elliptic curves
Silverman, Joseph H.
1990-10-01
Estimates for the difference of the Weil height and the canonical height of points on elliptic curves are used for many purposes, both theoretical and computational. In this note we give an explicit estimate for this difference in terms of the j-invariant and discriminant of the elliptic curve. The method of proof, suggested by Serge Lang, is to use the decomposition of the canonical height into a sum of local heights. We illustrate one use for our estimate by computing generators for the Mordell-Weil group in three examples.
[Clinical research XXI. From the clinical judgment to survival analysis].
Rivas-Ruiz, Rodolfo; Pérez-Rodríguez, Marcela; Palacios, Lino; Talavera, Juan O
2014-01-01
Decision making in health care implies knowledge of the clinical course of the disease. Knowing the course allows us to estimate the likelihood of occurrence of a phenomenon at a given time or its duration. Within the statistical models that allow us to have a summary measure to estimate the time of occurrence of a phenomenon in a given population are the linear regression (the outcome variable is continuous and normally distributed -time to the occurrence of the event-), logistic regression (outcome variable is dichotomous, and it is evaluated at one single interval), and survival curves (outcome event is dichotomous, and it can be evaluated at multiple intervals). The first reference we have of this type of analysis is the work of the astronomer Edmond Halley, an English physicist and mathematician, famous for the calculation of the appearance of the comet orbit, recognized as the first periodic comet (1P/Halley's Comet). Halley also contributed in the area of health to estimate the mortality rate for a Polish population. The survival curve allows us to estimate the probability of an event occurring at different intervals. Also, it leds us to estimate the median survival time of any phenomenon of interest (although the used term is survival, the outcome does not need to be death, it may be the occurrence of any other event).
Overview of Curved Cutting Edge Mills
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M. S. Potapova
2014-01-01
Full Text Available Now that there is a need to increase a processing capacity, curved cutting edge mills find ever-growing use. Also known as “rough end”, “full-side”, and “heavy-duty” mills, they provide the increased depth and width values of milling owing to the width-sized chip separation. The analysis of produced mills allowed us both to reveal their basic design components (type of a shaft or basic opening, diameter and length of the cutting part, mill length, quantity of teeth, a tilt angle of a screw flute and to make their classification. The paper presents a classification of the profile types of cutting edges, which can be divided by form (flat, round, size (small, large, super-large, and symmetry (symmetrical and asymmetrical. The profile of the cutting edge is characterized by the following parameters: profile height, pitch of crests spherical radius of crest.A review of the curved cutting edge profile types allows us to build the geometrical constructions to define a form and the sizes of the chip load made by the cutting edge from a billet. It is shown that parameters of the cutting edge profile influence the form and the sizes (thickness and width of the chip load.The chip load thickness provided by the curved cutting edge mills exceeds that of observed when using the “smooth” cutting edge mills. A thickening degree of the chip load is changed with changing form and sizes of the cutting edge mill profile. Larger thickening is observed if the chip load is limited from below and from above by the marks of a single tooth (the first or second etc., and a length of the other teeth marks is minimum. The most achievable chip load thickness is equal to feed per revolution.Studying the references allowed us to formulate some rules to choose a cutting edge profile depending on a type of the processed material and a desirable roughness of the processed surface. It is important to note the following.When choosing a profile of the cutting edge
Contrasting treatment-specific survival using double-robust estimators.
Zhang, Min; Schaubel, Douglas E
2012-12-30
In settings where a randomized trial is infeasible, observational data are frequently used to compare treatment-specific survival. The average causal effect (ACE) can be used to make inference regarding treatment policies on patient populations, and a valid ACE estimator must account for imbalances with respect to treatment-specific covariate distributions. One method through which the ACE on survival can be estimated involves appropriately averaging over Cox-regression-based fitted survival functions. A second available method balances the treatment-specific covariate distributions through inverse probability of treatment weighting and then contrasts weighted nonparametric survival function estimators. Because both methods have their advantages and disadvantages, we propose methods that essentially combine both estimators. The proposed methods are double robust, in the sense that they are consistent if at least one of the two working regression models (i.e., logistic model for treatment and Cox model for death hazard) is correct. The proposed methods involve estimating the ACE with respect to restricted mean survival time, defined as the area under the survival curve up to some prespecified time point. We derive and evaluate asymptotic results through simulation. We apply the proposed methods to estimate the ACE of donation-after-cardiac-death kidney transplantation with the use of data obtained from multiple centers in the Netherlands. Copyright © 2012 John Wiley & Sons, Ltd.
Ko, William L.; Jackson, Raymond H.
1990-01-01
The multilayer theory of anisotropic elasticity and a finite element method were used to analyze the open-mode delamination stress concentrations in horseshoe and elliptic laminated composite curved bars. Two types of laminations, solid laminations and sandwich laminations, were analyzed. It was found that the open-mode delamination stress concentration could be greatly increased in these two types of curved bars by decreasing their aspect ratios. The open-mode delamination stress concentration generated in the solid laminations was found to be far more severe than that generated in the sandwich laminations. The horseshoe curved bar may be used to determine both the open-mode delamination strength of solidly laminated composites and the open-mode debonding strength of sandwiched laminated composites. However, the elliptic curved bar is only good for determining the open-mode delamination strength of solidly laminated composites.