The Probability Density Function of Interest Rates Implied in the Price of Options

The paper contributes to the stochastic volatility literature by developing simulation schemes for the conditional distributions of the price of long term bonds and their variability based on non-standard distributional assumptions and volatility concepts; it illustrates the potential value of the information contained in the prices of options on long and short term lira interest rate futures for the conduct of monetary policy in Italy, at times when significant regime shifts have occured.stochastic models, statistical analysis, interest rates, financial market

Analysis of the scattering mechanisms controlling electron mobility in β-Ga2O3 crystals

Electron density and Hall mobility data were simultaneously analyzed in the frame of the relaxation time approximation in order to identify the main scattering mechanisms that limit the carrier mobility in β-Ga2O3 single crystals. The Hall factor correction was self-consistently included in the fitting procedure. The analysis indicates that low-energy optical phonons provide the main scattering mechanism, via lattice deformation. In this regard, a deformation potential of about 4×109 eV cm−1 was estimated. Furthermore, it is shown that the Hall coefficient and mobility can be measured by the usual experimental geometry, and the standard transport theory can be applied when off-diagonal elements of the resistivity tensor at zero magnetic field are negligible with respect to the diagonal ones. This directly follows from the analysis of the magneto-resistive tensor of a semiconductor with monoclinic structure. Such a requirement is satisfied under the hypothesis of nearly spherical energy surfaces, as has been reported to occur at the Γ minimum of the conduction band of β-Ga2O3

Crystal structure and ferroelectric properties of ϵ-Ga2O3 films grown on (0001)-sapphire

The crystal structure and ferroelectric properties of ϵ-Ga2O3 deposited by low-temperature MOCVD on (0001)-sapphire were investigated by single-crystal X-ray diffraction and the dynamic hysteresis measurement technique. A thorough investigation of this relatively unknown polymorph of Ga2O3 showed that it is composed of layers of both octahedrally and tetrahedrally coordinated Ga3+ sites, which appear to be occupied with a 66% probability. The refinement of the crystal structure in the noncentrosymmetric space group P63mc pointed out the presence of uncompensated electrical dipoles suggesting ferroelectric properties, which were finally demonstrated by independent measurements of the ferroelectric hysteresis. A clear epitaxial relation is observed with respect to the c-oriented sapphire substrate, with the Ga2O3 [10-10] direction being parallel to the Al2O3 direction [11-20], yielding a lattice mismatch of about 4.1%

Structural and optical investigation of non-polar (1-100) GaN grown by the ammonothermal method

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Journal of Applied Physics 113, 203513 (2013) and may be found at https://doi.org/10.1063/1.4807581.We studied the structural and optical properties of state-of-the-art non-polar bulk GaN grown by the ammonothermal method. The investigated samples have an extremely low dislocation density (DD) of less than 5 × 104 cm−2, which results in very narrow high-resolution x-ray rocking curves. The a and c lattice parameters of these stress-free GaN samples were precisely determined by using an x-ray diffraction technique based on the modified Bond method. The obtained values are compared to the lattice parameters of free-standing GaN from different methods and sources. The observed differences are discussed in terms of free-electron concentrations, point defects, and DD. Micro Raman spectroscopy revealed a very narrow phonon linewidth and negligible built-in strain in accordance with the high-resolution x-ray diffraction data. The optical transitions were investigated by cathodoluminescence measurements. The analysis of the experimental data clearly demonstrates the excellent crystalline perfection of ammonothermal GaN material and its potential for fabrication of non-polar substrates for homoepitaxial growth of GaN based device structures

Visuo-motor pathways in humans revealed by event-related fMRI

Whether different brain networks are involved in generating unimanual responses to a simple visual stimulus presented in the ipsilateral versus contralateral hemifield remains a controversial issue. Visuo-motor routing was investigated with event-related functional magnetic resonance imaging (fMRI) using the Poffenberger reaction time task. A 2 hemifield×2 response hand design generated the "crossed” and "uncrossed” conditions, describing the spatial relation between these factors. Both conditions, with responses executed by the left or right hand, showed a similar spatial pattern of activated areas, including striate and extrastriate areas bilaterally, SMA, and M1 contralateral to the responding hand. These results demonstrated that visual information is processed bilaterally in striate and extrastriate visual areas, even in the "uncrossed” condition. Additional analyses based on sorting data according to subjects' reaction times revealed differential crossed versus uncrossed activity only for the slowest trials, with response strength in infero-temporal cortices significantly correlating with crossed-uncrossed differences (CUD) in reaction times. Collectively, the data favor a parallel, distributed model of brain activation. The presence of interhemispheric interactions and its consequent bilateral activity is not determined by the crossed anatomic projections of the primary visual and motor pathways. Distinct visuo-motor networks need not be engaged to mediate behavioral responses for the crossed visual field/response hand condition. While anatomical connectivity heavily influences the spatial pattern of activated visuo-motor pathways, behavioral and functional parameters appear to also affect the strength and dynamics of responses within these pathway

Regaining Apical Patency with Manual and Reciprocating Instrumentation during Retreatment

Introduction: Different techniques have been proposed to help achieving apical patency during endodontic treatment and retreatment. The objective of this in vitro study was to compare reestablishment of apical patency in teeth previously subjected to root canal treatment using manual and reciprocating instruments. Methods and Materials: A total of 40 single-rooted extracted human mandibular incisors were selected and prepared using the Hero 642 sequence to 45/0.02 and obturated using Tagger’s hybrid technique to 1 mm short of the apex. Teeth were divided into two groups according to the type of instrument used to regain patency: group 1, hand K-files and group 2, reciprocating WaveOne Primary files (25/0.08). Fisher’s exact test was used in the statistical analysis. Result: In group1, apical patency was regained in 9 of the 20 teeth tested (46%), compared to 20 teeth (100%) in group 2. The difference between the groups was significant (P<0.0001). Conclusion: Our study shows that reciprocating instrumentation is more successful in regaining apical patency in single-rooted, previously treated teeth. Keywords: Apical Patency; Reciprocating; Retreatment; Root Canal Treatmen

Reported mortality for colorectal cancer in Brazil in the first 16 years of the 21st century

Introduction: Colorectal cancer (CRC) is a malignant neoplasm with major impact on health today. There is, however, an efficient method for prevention and screening, which varies in different protocols according to each institution or country. Objective: To evaluate the mortality rate and the economic cost of CRC in Brazil during the first 16 years of the 21st century. Method: A retrospective, temporal aggregation study was conducted with an exploratory, documentary quantitative approach on CRC mortality from 2000 to 2016, based on the Mortality Information System database provided by the Brazilian Ministry of Health. Results: In the study period, 218,000 deaths due to CRC were recorded. The CRC mortality rate was 6.2 (95% confidence interval, 5.59-6.81) per 100,000 population, with no significant difference between men and women. Of the 17 age subgroups analyzed, eight had a significant increase from 2000 to 2016, including all subgroups aged over 50 years. Conclusion: There was an increase in mortality due to CRC in the study period. Keywords: Mortality; colorectal cancer; Brazi