613 research outputs found
Latent separability and price variation in the estimation of demand System
The aim of this paper is to overcome the problems caused by insufficient price variation in estimating a large demand system. For that, we propose a new form of Stone-Lewbel (SL) cross section prices developed under latent separability that explore individual specific variation in the composition of the bundles of exclusive goods. The estimation of demand system under latent separability needs the choice of at least one exclusive good per group. We estimate Quadratic Almost Ideal Demand System (QAIDS) under weak and latent separability using traditional aggregate price indices and SL prices. Our empirical analysis is based on fifteen non durable goods of a Tunisian Family Expenditure Survey Data. The results show greater differences among effects price and estimates of price elasticities obtained under weak separability and latent separability using both traditional price indices and SL prices. We obtain higher precision of estimates of own price elasticities using SL prices under latent separability.Latent separability, Weak separability, Demand system, Exclusive goods, Price variation, SL prices
Magnetic Resonance Studies of the Red-Photochemistry of C-Nitroso Derivatives, and of the Action of NO and NO2 on Biologically Important Substances
This thesis begins, chapter one, with a general introduction to the photochemistry of C-nitroso compounds, nitroxide radicals, and photochemical reactions of some optically active geminal chloronitroso derivatives of terpenes. The remaining chapters of the thesis then describe the author's work on two important aspects of C-nitroso systems. 1) Photochemical reactions in solid 2-chloro-2-nitrosonorbomane Chapter two examines analyses of a sample of solid 2-chloro-2-nitrosonorbomane by means of infra red, mass spectroscopy and modem high resolution nuclear magnetic resonance spectroscopy. This work shows that the solid is racemic and dimeric, and contains mixtures of dd-, ll-, dl- and ld-isomers. It also enables the configuration at the >C(2)ClNO residue to be established. Detailed high resolution nuclear magnetic resonance spectroscopic studies show that in solutions, 2-chloro-2-nitrosonorbomane exists mainly in the monomeric form, in equilibrium with a small amount of the corresponding dimeric forms. Irradiation of the solid with red visible light causes some white crystals and a brown viscous oil to be formed. The components of these two phases have been identified. In order to account for the observed photolysis products, a reaction mechanism is postulated. This invokes a Beckmann-like rearrangement reaction which may be of general synthetic use for converting geminal chloronitroso derivatives into lactams which may be of pharmacological interest. In chapter three, information from the work described in chapter two is combined with work carried out by earlier investigators to show how circular dichroism studies can be combined with high resolution nuclear magnetic resonance spectroscopy to enable the configurations at optically active >CCINO centres of other geminal chloronitroso terpene derivatives to be determined. 2) Action of NO and NO2 on some biologically important substances In chapter four, it is pointed out that the work described in chapters 1-3 of this thesis may have significance for the agricultural and medical toxicology, including carcinogenesis, of compounds containing nitrogen. This chapter describes the results obtained from detailed spectroscopic studies of reactions that take place when some steroids, fatty acids, pyrimidine bases and purine bases of biological interest are brought into contact with acidified solutions of sodium nitrite. These studies show that acidified sodium nitrite affects steroids and almost certainly carbohydrates. It isomerises unsaturated fatty acids, and therefore almost certainly affects the permeability of cell membranes. It affects pyrimidine bases and purine bases, and almost certainly nucleosides, nucleotides and nucleic acids. It also affects amino acids and proteins. Acidified sodium nitrite must interfere with the genetic code. MO and NO2 must be implicated in some areas of carcinogenesis and in bacterial toxic shock
Real Time Lidar and Radar High-Level Fusion for Obstacle Detection and Tracking with evaluation on a ground truth
20th International Conference on Automation, Robotics and Applications Lisbon sept 24-25, 2018— Both Lidars and Radars are sensors for obstacle detection. While Lidars are very accurate on obstacles positions and less accurate on their velocities, Radars are more precise on obstacles velocities and less precise on their positions. Sensor fusion between Lidar and Radar aims at improving obstacle detection using advantages of the two sensors. The present paper proposes a real-time Lidar/Radar data fusion algorithm for obstacle detection and tracking based on the global nearest neighbour standard filter (GNN). This algorithm is implemented and embedded in an automative vehicle as a component generated by a real-time multisensor software. The benefits of data fusion comparing with the use of a single sensor are illustrated through several tracking scenarios (on a highway and on a bend) and using real-time kinematic sensors mounted on the ego and tracked vehicles as a ground truth
Impact of Chemical Aging on the Fracture Resistance of Two Ceramic Materials: Zirconia-Reinforced Lithium Silicate and Lithium Disilicate Ceramics
BACKGROUND: The reason for the development of high strength zirconia is that zirconia offers enough high strength of about 1000 MPa and high strength glass ceramic in the range of 360–400 MPa, to provide safely ceramic options for many indications.
AIM: This study aims to evaluate the fracture resistance of zirconia-reinforced lithium silicate (ZLS) ceramic and lithium disilicate ceramic restorations.
MATERIALS AND METHODS: In this in vitro study, forty crowns were fabricated by CAD/CAM technology, all samples were divided into two groups (n = 20) according to ceramic material used: Group Z ZLS ceramic (celtra due) and Group L lithium disilicate ceramic blocks (IPS E-MAX). Further subdivided into two subgroups according to the aging procedure (n = 10): (a) Subgroup – ZA: Aging. (b) Subgroup – ZB: No aging. (c) Subgroup – LA: Aging. (d) Subgroup – LB: No aging. All samples were subjected to universal testing machine (Instron) to evaluate the effect of the chemical aging on the fracture resistance.
STATISTICAL ANALYSIS: One-way ANOVA analysis was used to compare measurements among groups.
RESULTS: ZLS showed higher fracture resistance than lithium disilicate, but there was no statistical difference between them. Aging affected on the fracture resistance of two different ceramic materials but within an acceptable range.
CONCLUSION: ZLS gave rise to higher fracture resistance than lithium disilicate and aging decrease fracture resistance of both types of ceramic. The postulated hypothecs of this study were zirconia reinforced, lithium silicate will be higher fracture resistance than lithium disilicate, and chemical aging will have a huge effect
New Watermarking/Encryption Method for Medical Imaging FULL Protection in m-Health
In this paper, we present a new method for medical images security dedicated to m-Health based on a combination between a novel semi reversible watermarking approach robust to JPEG compression, a new proposed fragile watermarking and a new proposed encryption algorithm. The purpose of the combination of these three proposed algorithms (encryption, robust and fragile watermarking) is to ensure the full protection of medical image, its information and its report in terms of confidentiality and reliability (authentication and integrity). A hardware implementation to evaluate our system is done using the Texas instrument C6416 DSK card by converting m-files to C/C++ using MATLAB coder. Our m-health security system is then run on the android platform. Experimental results show that the proposed algorithm can achieve high security with good performance
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