scholarly journals Nelson-Siegel Model Approach to the Euro Area Yield Curves

2017 ◽  
Vol 56 (1) ◽  
pp. 53-63
Author(s):  
Akvilė Mazanauskaitė
Keyword(s):  
Euro Area ◽  
Static Model ◽  
Yield Curves ◽  
Treasury Bills ◽  
Best Fitting ◽  
The Mean ◽  
Model Approach

In this paper Nelson-Siegel model has been examined. The main purpose of this paper is to fit the best Nelson-Siegel model to the Euro Area yield curves and to compare with Lithuanian yields in order to draw conclusions about readiness of Lithuania to join the Euro Area. In order to succeed in achieving the goal, Euro Area zero coupon bonds have been examined and various static Nelson-Siegel models were developed. Also, the mean of absolute errorof the Lithuanian government treasury bills was calculated using the best-fitting Nelson-Siegel model of the Euro Areayields. The results have shown that if the static model is calculated for each year, the yield are described precisely in the model.

scholarly journals Thermal annealing of implanted <sup>252</sup>Cf fission tracks in monazite

Geochronology ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 89-102
Author(s):  
Sean Jones ◽  
Andrew Gleadow ◽  
Barry Kohn
Keyword(s):  
Thermal Annealing ◽  
Fission Track ◽  
Closure Temperature ◽  
Fission Tracks ◽  
Temperature Ranges ◽  
Best Fitting ◽  
The Mean ◽  
Oriented Parallel ◽  
Increasing Temperature ◽  
Ambient Surface

Abstract. A series of isochronal heating experiments were performed to constrain monazite fission track thermal annealing properties. The 252Cf fission tracks were implanted into monazite crystals from the Devonian Harcourt granodiorite (Victoria, Australia) on polished surfaces oriented parallel to (100) pinacoidal faces and perpendicular to the crystallographic c axis. Tracks were annealed over 1, 10, 100 and 1000 h schedules at temperatures between 30 and 400 ∘C. Track lengths were measured on captured digital image stacks and then converted to calculated mean lengths of equivalent confined fission tracks that progressively decreased with increasing temperature and time. Annealing is anisotropic, with tracks on surfaces perpendicular to the crystallographic c axis consistently annealing faster than those parallel to the (100) face. To investigate how the mean track lengths decreased as a function of annealing time and temperature, one parallel and two fanning models were fitted to the empirical dataset. The temperature limits of the monazite partial annealing zone (MPAZ) were defined as length reductions to 0.95 (lowest) and 0.5 (highest) for this study. Extrapolation of the laboratory experiments to geological timescales indicates that for a heating duration of 107 years, estimated temperature ranges of the MPAZ are −44 to 101 ∘C for the parallel model and −71 to 143 ∘C (both ±6–21 ∘C, 2 standard errors) for the best-fitting linear fanning model (T0=∞). If a monazite fission track closure temperature is approximated as the midpoint of the MPAZ, these results, for tracks with similar mass and energy distributions to those involved in spontaneous fission of 238U, are consistent with previously estimated closure temperatures (calculated from substantially higher energy particles) of < 50 ∘C and perhaps not much higher than ambient surface temperatures. Based on our findings we estimate that this closure temperature (Tc) for fission tracks in monazite ranges between ∼ 45 and 25 ∘C over geological timescales of 106–107 years, making this system potentially useful as an ultra-low-temperature thermochronometer.

Abstract 6207: Derivation of a Novel Prediction Algorithm for Idiopathic Venous Thromboembolism in Women

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Brendan M Everett ◽  
Nina P Paynter ◽  
Julie E Buring ◽  
Robert J Glynn ◽  
Nancy R Cook ◽  
...  
Keyword(s):  
Venous Thromboembolism ◽  
Factor V Leiden ◽  
Information Criterion ◽  
Apolipoprotein A1 ◽  
Prediction Algorithm ◽  
Factor V ◽  
Risk Reclassification ◽  
Best Fitting ◽  
The Mean ◽  
Caucasian Women

Background : Established risk factors for idiopathic venous thromboembolism (VTE) include age, prothrombotic mutations, and obesity. A risk prediction algorithm might allow clinicians to focus preventive efforts. Methods : We derived a prediction model for idiopathic VTE using 22 possible predictor variables and their interactions in 19,458 initially healthy Caucasian women who were followed for incident idiopathic VTE. Minimization of the Bayes Information Criterion (BIC) was used to help identify the best, most parsimonious model, and estimates of discrimination (C-index) and calibration (Hosmer-Lemeshow (H-L) statistic) comparing observed and predicted risk were computed and compared with a model including only age and weight. Results: The mean (SD) age was 54.1 (7.1) years, the mean (SD) weight 69.9 (14.1) kilograms, and 2.8% and 5.3% of participants carried the prothrombin and factor V Leiden mutations, respectively. After a median of 12.4 years of follow up, we observed 130 idiopathic cases of VTE. The best fitting model included log(age), log(weight), log(apolipoprotein A1), and the presence of the prothrombin or factor V Leiden mutations (C-index 0.704; H-L statistic 5.9). When compared to model including only log(age) and log(weight) (C-index 0.636; H-L statistic 3.9), the full model achieved higher discrimination at similar calibration and led to a net reclassification of 34.5 percent (6705) of participants, all correctly. Conculsion: In our population of middle-aged, initially healthy Caucasian women, a model that includes age, weight, apolipoprotein A1, and the prothrombin and factor V Leiden mutations predicts incident idiopathic VTE more accurately than one including age and weight alone. Table. Idiopathic venous thromboembolism risk reclassification - basic and best-fitting models

The Content of IMF Staff Reports for Euro Area Countries

2014 ◽  
pp. 272-292
Author(s):  
Lena Golubovskaja
Keyword(s):  
Standard Deviation ◽  
Euro Area ◽  
Mean Value ◽  
Systematic Bias ◽  
Executive Board ◽  
Sample Mean ◽  
Warning Tone ◽  
The Mean ◽  
Run Up ◽  
The Imf

This chapter analyzes the tone and information content of the two external policy reports of the Internal Monetary Fund (IMF), the IMF Article IV Staff Reports, and Executive Board Assessments for Euro area countries. In particular, the researchers create a tone measure denoted WARNING based on the existing DICTION 5.0 Hardship dictionary. This study finds that in the run-up to the current credit crises, average WARNING tone levels of Staff Reports for Slovenia, Luxembourg, Greece, and Malta are one standard deviation above the EMU sample mean; and for Spain and Belgium, they are one standard deviation below the mean value. Furthermore, on average for Staff Reports over the period 2005-2007, there are insignificant differences between the EMU sample mean and Staff Reports’ yearly averages. Researchers find the presence of a significantly increased level of WARNING tone in 2006 (compared to the previous year) for the IMF Article IV Staff Reports. There is also a systematic bias of WARNING scores for Executive Board Assessments versus WARNING scores for the Staff Reports.

Temporal Trends and Future Predictions of Regional EMS System Utilization Using Statistical Modeling

2019 ◽  
Vol 35 (1) ◽  
pp. 32-40 ◽  
Author(s):  
Michael J. Carr ◽  
Robert Bauter ◽  
Philip Shepherd ◽  
Vincent Robbins ◽  
A.J. McKechnie ◽  
...  
Keyword(s):  
Life Support ◽  
Temporal Trends ◽  
Computer Assisted ◽  
Service Access ◽  
Best Fitting ◽  
Per Capita ◽  
Increasing Trends ◽  
Future Utilization ◽  
Model Approach ◽  
Call Volume

AbstractIntroduction:Trends in utilization of Emergency Medical Services (EMS) systems can be used to extrapolate future use of an EMS system, which will be valuable for the budgeting and planning of finances and resources. The best model for incorporation of seasonal and regional fluctuations in utilization to predict future utilization is unknown.Problem:Authors aimed to trend patterns of utilization in a regional EMS system to identify the needs of a growing population and to allow for a better understanding of how the EMS system is used on a basis of call volume and frequency of EMS transportation. The authors then used a best-fitting prediction model approach to show how the studied EMS system will be used in future years.Methods:Systems data were retrospectively extracted by using the electronic medical records of the studied EMS system and its computer-assisted dispatch (CAD) database from 2010 through 2017. All EMS dispatches entering the system’s 9-1-1 public service access point were captured. Annual utilization data were available from 2010 through 2017, while quarterly data were available only from 2013 through 2017. The 9-1-1 utilization per capita, Advanced Life Support (ALS) utilization per capita, and ALS cancel rates were calculated and trended over the study period. The methods of prediction were assessed through a best-fitting model approach, which statistically suggested that Additive Winter’s approach (SAS) was the best fit to determine future utilization and ALS cancel rates.Results:Total 9-1-1 call volume per capita increased by 32.46% between 2010 and 2017, with an average quarterly increase of 0.78% between 2013 and 2017. Total ALS call volume per capita increased by 1.93% between 2010 and 2017. Percent ALS cancellations (cancelled en route to scene) increased by eight percent between 2010 and 2017, with an average quarterly increase of 0.42% (2013–2017). Predictions to end of 2019 using Additive Winter’s approach demonstrated increasing trends in 9-1-1 call volume per capita (R2 = 0.47), increasing trends of ALS utilization per capita (R2 = 0.71), and increasing percent ALS cancellation (R2 = 0.93). Each prediction showed increasing future trends with a 95% confidence interval.Conclusions:The authors demonstrate paramount per capita increases of 9-1-1 call volume in the studied ALS system. There are concomitant increases of ALS cancellations prior to arrival, which suggests a potential burden on this regional ALS response system.

scholarly journals Convergence and Anchoring of Yield Curves in the Euro Area

2011 ◽  
Vol 93 (1) ◽  
pp. 350-364 ◽  
Author(s):  
Michael Ehrmann ◽  
Marcel Fratzscher ◽  
Refet S Gürkaynak ◽  
Eric T Swanson
Keyword(s):  
Euro Area ◽  
Yield Curves

The Anatomy of the Callosomarginal Artery

Neurosurgery ◽  
2010 ◽  
Vol 66 (3) ◽  
pp. 602-610 ◽  
Author(s):  
Daniel D. Cavalcanti ◽  
Felipe C. Albuquerque ◽  
Benjamin F. Silva ◽  
Robert F. Spetzler ◽  
Mark C. Preul
Keyword(s):  
Anterior Cerebral Artery ◽  
Convex Curve ◽  
Anterior Communicating Artery ◽  
Morphometric Measurements ◽  
Pericallosal Artery ◽  
Mean Diameter ◽  
Best Fitting ◽  
The Mean ◽  
Definition Of ◽  
Distal Anterior Cerebral Artery

Abstract BACKGROUND The callosomarginal artery (CMA), the main branch of the pericallosal artery, courses in or near the cingulate sulcus and gives rises to 2 or more major cortical branches. There is confusion about the artery best fitting the definition of “callosomarginal artery.” Distal anterior cerebral artery aneurysms represent 1.5% to 9% of intracranial aneurysms, and most often occur at the origin of the CMA. The microsurgical anatomic features of the CMA, its relationship with the pericallosal artery, and clinical implications are presented. METHODS The origin, course, branching pattern, and diameter of the CMA and its branches and its relationship with the pericallosal artery were studied in 60 cerebral hemispheres, including cadaveric dissections and angiographic images. RESULTS The CMA was present in 93.3% of hemispheres studied and arose mainly from A3 (55.2%), a mean of 3.11 ± 1.90 cm from the anterior communicating artery. The mean diameter of the CMA at its origin was 1.53 ± 0.36 mm. The CMA ran 1.28 ± 0.89 cm until its first branch, describing an anterior convex curve backward and upward (60.7%). An average of 3 lesser branches originated from the CMA. The most consistent branch was the posterior internal frontal artery (67.9%). The mean diameter of the CMA branches was 0.93 ± 0.33 mm. CONCLUSION These morphometric measurements can help neurosurgeons access lesions located in distal intracranial vessels. The vessel coursing the longest pathway in or near the cingulate sulcus and otherwise following Moscow's classic definition should be considered the CMA.

scholarly journals Statistics of the polarized submillimetre emission maps from thermal dust in the turbulent, magnetized, diffuse ISM

2018 ◽  
Vol 614 ◽  
pp. A124 ◽  
Author(s):  
F. Levrier ◽  
J. Neveu ◽  
E. Falgarone ◽  
F. Boulanger ◽  
A. Bracco ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Power Spectrum ◽  
Spectral Index ◽  
Molecular Cloud ◽  
Analysis Framework ◽  
Gas Density ◽  
Best Fitting ◽  
The Mean ◽  
Polarization Fraction ◽  
Fitting Parameters

Context. The interstellar medium (ISM) is now widely acknowledged to display features ascribable to magnetized turbulence. With the public release of Planck data and the current balloon-borne and ground-based experiments, the growing amount of data tracing the polarized thermal emission from Galactic dust in the submillimetre provides choice diagnostics to constrain the properties of this magnetized turbulence. Aims. We aim to constrain these properties in a statistical way, focussing in particular on the power spectral index βB of the turbulent component of the interstellar magnetic field in a diffuse molecular cloud, the Polaris Flare. Methods. We present an analysis framework based on simulating polarized thermal dust emission maps using model dust density (proportional to gas density nH) and magnetic field cubes, integrated along the line of sight (LOS), and comparing these statistically to actual data. The model fields are derived from fractional Brownian motion (fBm) processes, which allows a precise control of their one- and two-point statistics. The parameters controlling the model are (1)–(2) the spectral indices of the density and magnetic field cubes, (3)–(4) the RMS-to-mean ratios for both fields, (5) the mean gas density, (6) the orientation of the mean magnetic field in the plane of the sky (POS), (7) the dust temperature, (8) the dust polarization fraction, and (9) the depth of the simulated cubes. We explore the nine-dimensional parameter space through a Markov chain Monte Carlo analysis, which yields best-fitting parameters and associated uncertainties. Results. We find that the power spectrum of the turbulent component of the magnetic field in the Polaris Flare molecular cloud scales with wavenumber as k−βB with a spectral index βB = 2.8 ± 0.2. It complements a uniform field whose norm in the POS is approximately twice the norm of the fluctuations of the turbulent component, and whose position angle with respect to the north-south direction is χ0 ≈−69°. The density field nH is well represented by a log-normally distributed field with a mean gas density 〈nH〉≈40 cm−3, a fluctuation ratio σnH/〈nH〉≈1.6, and a power spectrum with an index βn=1.7−0.3+0.4. We also constrain the depth of the cloud to be d ≈ 13 pc, and the polarization fraction p0 ≈ 0.12. The agreement between the Planck data and the simulated maps for these best-fitting parameters is quantified by a χ2 value that is only slightly larger than unity. Conclusions. We conclude that our fBm-based model is a reasonable description of the diffuse, turbulent, magnetized ISM in the Polaris Flare molecular cloud, and that our analysis framework is able to yield quantitative estimates of the statistical properties of the dust density and magnetic field in this cloud.

Least-squares Analysis of Fabric Data: A Note on Conical, Cylindroidal and Near–cylindroidal Folds

1971 ◽  
Vol 8 (6) ◽  
pp. 694-697 ◽  
Author(s):  
C. S. Venkitasubramanyan
Keyword(s):  
Least Squares ◽  
Stereographic Projection ◽  
Rotation Axis ◽  
Computational Procedure ◽  
Apical Angle ◽  
Small Circle ◽  
Best Fitting ◽  
Fabric Diagrams ◽  
The Mean

A cylinder and a plane may be considered as special limiting cases for a right circular cone as the semi-apical angle approaches 0° and 90° respectively (Loudon 1964, Kelley 1966). If these forms are viewed as surfaces generated by an array of lines in space, the rotation axis for the array (the axis of the "cone") can be determined from the orientations of the surface-generating lines by a single computational procedure, using least-squares criterion. The mean angle between the rotation axis and the surface-generating lines will be the semi-apical angle of the cone. However, if this method for determination of the semi-apical angle of the cone, and therefore the best-fitting small circle, is extended to fabric diagrams, in which an array of lines may only statistically describe a great circle or small circle on a stereographic projection, ambiguities arise in certain cases and the semi-apical angle obtained may not be the true semi-apical angle. The difficulty arises because the poles to foliation surfaces are arbitrarily assigned "senses".

scholarly journals Economics and Technical Efficiency of Maize Production Among Small Scale Farmers in Abuja, Nigeria: Stochastic Frontier Model Approach

2020 ◽  
Vol 2 (6) ◽  
Author(s):  
E. S. Ebukiba ◽  
L. Anthony ◽  
S. M. Adamu
Keyword(s):  
Stochastic Frontier ◽  
Farm Size ◽  
Small Scale ◽  
Stochastic Frontier Model ◽  
Gross Margin ◽  
Maize Production ◽  
Factors Influencing ◽  
The Mean ◽  
Small Scale Farmers ◽  
Model Approach

This study evaluated Economics and Technical Efficiency of Maize Production Among Small Scale Farmers in Abuja, Nigeria; Stochastic Frontier Model Approach; Multi-stage sampling technique was adopted and used. Primary data were collected through the use of well-structured questionnaire from one hundred and fifty (150) sampled respondents in the study area. Data were analyzed to achieve the specified objectives using the following tools of analysis, Descriptive Statistics, Stochastic Frontier, Gross Margin Analysis, Financial Analysis, Five Point Likert Scale, and Principal Components Analysis. The results show that majority 40.47% of the sampled respondents were among the age range of 41-50 years of age and 25.33% were within the age bracket of 31-40 years of age. The mean age of the sampled farmers is 44 years. Which indicated that Young and energetic farmers are able to withstand stress and adopt new innovations. Most 88.67% of the farmers were male. Majority 72.67% were married. The mean household size of the sampled respondents is 6 members per family. Majority (67%) of the small-scale maize farmers had 1-2 ha of land and the average farm size cultivated by the farmers was 2.576 ha. The factors influencing total output of maize were seed input (P<0.01), Farm Size (P<0.05), quantity of fertilizer (P<0.05), and labour input (P<0.01) were statistically significant variables. The results of the inefficiency components show that the factors influencing technical inefficiency includes: age (P<0.01), education (P<0.01), access to credit (P<0.05), farming experience, and household size (P<0.05) and were statistically significant. The total revenue realized by the sampled small-scale maize farmers was N238,317 on average. While the total variable costs on average basis was N109,702.93. The gross margin realized was N128667.07. The gross margin ratio was 0.54 while operating ratio calculated was 0.857 and the rate of return on investment (RORI) was 1.17. The retained component from the constraint’s analysis include Lack of Improve Seed, Lack of Transportation, Poor Storage Facilities, Inadequate Capital, and Cattle Herdsmen. The retained components explained 60% of the variation of the component included in the model. The study therefore, recommends that affordable loans and adequate capital should be made available to the small-scale maize farmers, farmers should be properly trained and educated by the non-governmental organizations and extension agents on chemical application, fertilizer use and pests and diseases control measures especially on integrated pest management (IPM). Inputs like improve seeds, fertilizer, and chemicals should be made available to farmers at subsidized rates and at appropriate time coinciding with production periods for proper usage. Provisions should be made for transportation and storage facilities for farmers, the issue of conflict between farmers and herdsmen should be brought to book and resolved amicably for peaceful coexistence.

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