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Elasticity
Kinds of Elasticity Terms modified by Elasticity Selected AbstractsElasticities of market shares and social health insurance choice in germany: a dynamic panel data approachHEALTH ECONOMICS, Issue 3 2007Marcus Tamm Abstract In 1996, free choice of health insurers was introduced to the German social health insurance system. One objective was to increase efficiency through competition. A crucial precondition for effective competition among health insurers is that consumers search for lower-priced health insurers. We test this hypothesis by estimating the price elasticities of insurers' market shares. We use unique panel data and specify a dynamic panel model to explain changes in market shares. Estimation results suggest that short-run price elasticities are smaller than previously found by other studies. In the long-run, however, estimation results suggest substantial price effects. Copyright © 2006 John Wiley & Sons, Ltd. [source] Aggregation Bias in Elasticities of Substitution and the Minimum Wage ParadoxINTERNATIONAL ECONOMIC REVIEW, Issue 2 2000Coen N. Teulings While the employment effects of minimum wages are usually reported to be small (suggesting low substitutability between skill types), direct estimates suggest a much larger degree of substitutability. This article argues that this paradox is largely due to a bias induced by the aggregation of skill types into broad categories. An assignment model is applied where skilled workers have a comparative advantage in complex jobs. The implied pattern of substitutability reveals the sources of the bias. Estimation results for the United States show elasticities of complementarity to be underestimated by up to a factor 2.5. The methods laid out likewise can be applied to other markets where different quality types are close substitutes, such as the housing market. [source] Time-varying Armington elasticity and country-of-origin bias: from the dynamic perspective of the Japanese demand for beef importsAUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 1 2010Shigekazu Kawashima Elasticities of substitution, often called Armington elasticities, reflect incomplete substitutability because of perceived product characteristics. This study divides the determinants of the Japanese demand for beef imports into two factors: (i) substitution elasticity and (ii) country-of-origin bias, and demonstrate how these measurements are associated with trade policy and food scare events. The Japanese beef industry serves as a case study to evaluate the multifold impact of import liberalisation and a series of bovine spongiform encephalopathy (BSE) outbreaks. A time-varying parameter model is used to shed light on the dynamic effects of the import liberalisation and BSE outbreaks on the measurements. The estimation results reveal that the estimated substitutability and country-of-origin bias are very sensitive to the BSE cases, but not to the process of trade liberalisation. The results also confirm that as a result of the BSE outbreaks, the major factor of the Japanese demand for beef imports has changed from relative prices to the country-of-origin effect, thereby emphasising the importance of a traceability system and promotional activities, which would help in the formation of the country-of-origin effect. [source] On introducing approximate solution methods in theory of elasticityCOMPUTER APPLICATIONS IN ENGINEERING EDUCATION, Issue 2 2006Autar Kaw Abstract This work presents how approximate solution methods were introduced in a graduate level course of Theory of Elasticity. The three methods introduced are the finite difference method, the finite element method, and the boundary element method. All methods are exemplified by the problem of a thick-walled cylinder subject to internal pressure with an axisymmetric response. Choosing a single problem to introduce the three methods demonstrates accuracy and efficacy of each method. © 2006 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 120,134, 2006; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20070 [source] Aortic Upper Wall Tissue Doppler Image Velocity: Relation to Aortic Elasticity and Left Ventricular Diastolic FunctionECHOCARDIOGRAPHY, Issue 9 2009Soon Yong Suh M.D. Background: Aortic stiffening contributes to the left ventricular (LV) afterload, hypertrophy, and substrate for diastolic dysfunction. It is also known that aortic elastic properties could be investigated with color tissue Doppler imaging (TDI) in aortic upper wall. The purpose of this study is to evaluate the relation of aortic upper wall TDI and aortic stiffness and other parameters of LV diastolic function. Methods: We examined aortic upper wall by TDI at the 3 cm above the aortic valves because of patient's chest discomfort or dyspnea. We excluded the patient with arterial hypertension or reduced left ventricular ejection fraction (LVEF) or significant valvular heart disease. So a total of 126 (mean age 53.8 ± 13.9 years, male 49.2%) patients were enrolled in this study and divided normal LV filling group (N = 31) and abnormal LV filling group (N = 95). Results: Aortic upper wall early systolic velocity and late diastolic velocity were not different between the two groups. Only aortic upper wall early diastolic velocity (AWEDV) was related to aortic stiffness index (r =,0.25, P = 0.008), distensibility (r = 0.28, P = 0.003), early diastolic (Em) (r = 0.45, P = 0.001), E/Em (r =,0.26, P = 0.003), and significantly reduced in abnormal LV filling group (6.19 ± 2.50 vs 8.18 ± 2.87, P = 0.001). Conclusions: AWEDV is decreased significantly in abnormal LV filling patients. It is statistically related to aortic stiffness, distensibility and parameters of abnormal LV filling, Em, E/Em. TDI velocity of the aortic upper wall can be a helpful tool for evaluating aortic stiffness, distensibility, and diastolic function. [source] A Comparison of Echocardiographic Techniques in Determination of Arterial Elasticity in the Pediatric PopulationECHOCARDIOGRAPHY, Issue 5 2009Michael Fahey M.D. Background: Many methods are used to measure arterial elasticity in children using echocardiography. There is no data to support the equivalence of the different techniques. The goal of this study was to evaluate the reproducibility of several techniques used to measure arterial elasticity using echocardiography. Methods: Aortic distension in two different sites (arterial distension) through the cardiac cycle was measured by (four) two-dimensional (2D) and M-mode echocardiographic techniques in 20 children without significant structural heart disease. These measurements combined with noninvasive blood pressure measurements were used to calculate arterial elastic indices. Arterial elasticity was expressed in terms of distensibility and stiffness. Data were collected by two sonographers and interpreted by two reviewers. Paired Student's t-test and Pitman's test for equality of variance for correlated observations were used to detect differences between different sonographers, different reviewers, and different techniques. Results: No significant difference in the measured elasticity between sonographers or reviewers was observed. There was a somewhat increased variance in two of the four techniques evaluated. There was no significant difference in elasticity measured using different techniques to evaluate the same arterial site, although a significantly decreased elasticity was noted from measurements taken in the proximal ascending aorta as compared with the distal ascending aorta. Conclusions: Many echocardiographic techniques produce reproducible measurements of arterial elasticity. There may be intrinsic differences in arterial elasticity between different segments of the ascending aorta, which have not been previously described in children with normal cardiac anatomy. Comparisons of data from separate studies must take these differences into account. [source] A Shred of Credible Evidence on the Long-run Elasticity of Labour SupplyECONOMICA, Issue 308 2010ORLEY ASHENFELTER All public policies regarding taxation and the redistribution of income rely on assumptions about the long-run effect of wages rates on labour supply. The variation in existing estimates calls for a simple, natural experiment in which men can change their hours of work, and in which wages have been exogenously and permanently changed. We use a panel dataset of taxi drivers who choose their own hours, and who experienced two exogenous permanent fare increases, and estimate an elasticity of labour supply of ,0.2, implying that income effects dominate substitution effects in the long-run labour supply of males. [source] Multiple-point electrochemical detection for a dual-channel hybrid PDMS-glass microchip electrophoresis deviceELECTROPHORESIS, Issue 19 2009Mario Castaño-Álvarez Abstract A new PDMS-based dual-channel MCE with multiple-point amperometric detection has been evaluated. Electrophoresis has been optimised in a single-channel device. Pretreatment with 0.1,M NaOH is very important for increasing and stabilising the EOF. The precision is adequate for a day's work in terms of both peak current and migration time. The RSD of the peak current for five successive signals was 1.9, 2.4 and 3.1% for dopamine, p- aminophenol and hydroquinone. RSD for the migration time was always less than 1.3%, which demonstrates the stability of the EOF and the possibility of running multiple experiments in the same microchip. The adequate inter-microchip precision as well as the rapid and simple manufacturing procedure indicates the disposable nature of the PDMS microchips. A dual-channel device with very simple multiple-point amperometric detection is proposed here. Elasticity of the PDMS allows removing the polymer slightly and aligning gold wires working electrodes. Injection can be performed from each of the sample reservoirs or from both simultaneously. The distance between the separation channels is critical for obtaining adequate signals as well as the introduction of a high-voltage electrode in the buffer reservoir. Simultaneous measurement of the same analytes in both channels is possible by applying the same potential. Moreover, since no cross-separation is produced, different analytes or samples can be simultaneously measured. [source] Strain-Gradient Elasticity for Bridging Continuum and Atomistic Estimates of Stiffness of Binary Lennard-Jones CrystalsADVANCED ENGINEERING MATERIALS, Issue 6 2010Andrei A. Gusev Lagrangian variational approach is employed to derive the equations of equilibrium of strain-gradient elasticity. For a periodic lamellar-morphology strain-gradient medium, we present an exact formula for the overall, system stiffness. We compare the formula with direct atomistic estimates of stiffness of binary Lennard-Jones crystals. The comparison reveals that the strain-gradient formula remains fairly accurate for all the crystals studied, including those with order of unity atoms in the crystal unit cell. Thus, one can surmise that the strain-gradient correction alone can already be sufficient to extend the scope of validity of continuum-level elasticity to near atomistic length scales. [source] Size-Dependence and Elasticity of Liquid-Crystalline Multiwalled Carbon Nanotubes,ADVANCED MATERIALS, Issue 16 2008Wenhui Song Profound size-effects of liquid-crystalline microstructures of multiwalled carbon nanotube dispersions are reported. The figure shows that nanotubes behave like rigid rods in the case of a low aspect ratio; however, they behave as flexible beams that deform easily following the local orientation in a liquid crystalline field if they are thin and/or long with a relatively high aspect ratio. [source] Stereoblock Polypropylene as a Prototype Example of Elasticity via a Flip-Flop Reorientation of Crystals in a Compliant Matrix,ADVANCED MATERIALS, Issue 6 2007F. Auriemma Elastomeric polypropylene characterized by chains with an isotactic and atactic stereoblock structure shows elastic behavior in a large range of deformations notwithstanding the high degree of crystallinity, because of the occurrence of flip-flop reversible reorientation of crystals of the , form that occur during stretching and the successive release of tension, as shown schematically in the figure. [source] Gonochorism vs. hermaphroditism: relationship between life history and fitness in three species of Ophryotrocha (Polychaeta: Dorvilleidae) with different forms of sexualityJOURNAL OF ANIMAL ECOLOGY, Issue 1 2006DANIELA PREVEDELLI Summary 1The relationships between life history, fitness and sexuality, together with their ecological and evolutionary significance, has been analysed comparing the main life-history traits and demography in three closely related species belonging to the genus Ophryotrocha. The species are: the gonochoristic O. labronica, the simultaneous hermaphrodite O. diadema and the protandrous hermaphrodite O. puerilis. 2Survivorship and reproductive data were collected weekly and were used to construct life tables and population projection matrices for each species and compare life-history characteristics. Elasticity, life-table response and decomposition analyses were performed to examine the relative contribution of fecundity and survivorship to differences in , between species. 3The gonochoristic and hermaphroditic species differ in all the main life-history parameters and also in demographic characteristics. In particular the value of ,, used commonly to express fitness, is markedly higher in the gonochoristic species while in terms of fitness simultaneous and sequential hermaphroditism are very similar. In the genus Ophryotrocha gonochorism currently represents the most widespread condition, being characteristic of the majority of the known species in the genus. 4Given the demographic advantage ensured by gonochorism, it remains be understood why some species have retained simultaneous hermaphroditism and one has evolved a sequential type hermaphroditism; the most probable hypothesis is correlated with the density of the species in natural habitats. [source] Influence of Bone Tissue Density and Elasticity on Ultrasound Propagation: An In Vitro StudyJOURNAL OF BONE AND MINERAL RESEARCH, Issue 12 2000Francesca de Terlizzi Abstract Ultrasound (US) waves are mechanical vibrations that are applied to a material,bone tissue,in order to study its properties, that is, density, elasticity, and structure. In this study we evaluated in which way density and elasticity of the spongy bone influenced the transmission of 1.25 MHz US pulses. Twelve cylindrical specimens (diameter, 8 mm; height, 5 mm) excised from phalanxes of pig were decalcified with 0.5 M EDTA for different times (0, 2, and 5 days). During these periods, the samples underwent the following investigations: US transmission, density, and elasticity measurements. To assess the homogeneity of decalcification, the cross-sections of some samples were microradiographed. A detailed analysis of the US signal received was performed using velocity, Fourier analysis, and some parameters typical of signal processing technique. A good correlation was found between US velocity and density (r2 = 0.70); a lower correlation was found between velocity and elasticity (r2 = 0.59). If density and elasticity are considered simultaneously, the correlation with the US velocity improves significantly (r2 = 0.84). Fourier analysis enabled us to observe a shift of the main frequency toward lower values as the decalcification process advanced. We also observed that in the regressions weighted for density, US velocity correlated poorly with elasticity (r2 = 0.16), whereas signal processing parameters maintain a good correlation with elasticity (ultrasound peak amplitude [UPA], r2 = 0.48; slope, r2 = 0.62). In this study, it has been observed that when using a signal processing technique to analyze US pulses, it is possible to identify some parameters that are related in different ways to density and to elastic properties of bone. Our results show the potentiality of US technique to separate information on bone density and elasticity that X-ray-based densitometric methods do not provide. [source] Changes of articular cartilage after immobilization in a rat knee contracture modelJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2009Yoshihiro Hagiwara Abstract The objective was to determine the changes of articular cartilage of the knee joint during immobilization in a rat model. The knee joints of adult male rats were immobilized at 150° of flexion using an internal fixator for 3 days, and 1, 2, 4, 8, and 16 weeks. The articular cartilage from the medial midcondylar region of the knee was obtained, divided into three areas (non-contact area, transitional area, contact area), and in each area, a degree of degeneration was evaluated by gross observation, histomorphometric grading, and measurements of thickness and number of chondrocytes. Elasticity of the articular cartilage was estimated by measuring the sound speed with use of scanning acoustic microscopy. Degeneration of the articular cartilage was mainly observed in the contact and transitional areas. Matrix staining intensity by safranin-O and number of chondrocytes were decreased in these two areas. The thickness of the articular cartilage in the non-contact and contact areas was unchanged, but it was increased in the transitional area. Decrease in sound speed was observed in the transitional area of both the femoral and tibial cartilage, indicating the softening of the articular cartilage. The changes of articular cartilage became obvious as early as 1 week after immobilization. These changes may be due to a lack of mechanical stress or a lack of joint fluid circulation during immobilization. Although we do not know the reversibility of these changes of articular cartilage, early mobilization is preferable to avoid these cartilage changes. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:236,242, 2009 [source] Effectiveness of LPG® treatment in morpheaJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 5 2004W-I Worret ABSTRACT Background, The LPG® technique, also known as Endermology® treatment, is a noninvasive technique consisting of a tissue mobilization process in which a skin fold is created between two rollers, stretching the underlying tissue and mobilizing the fold. The LPG® technique is very effective in treating scars. Because the lesions of morphea or circumscribed scleroderma are similar to atrophic scars, it seemed reasonable to treat them with a method proven helpful for scars. Materials and methods, We treated 17 lesions of 10 patients (four males and six females) with the diagnosis of morphea ranging in age from 17 to 78 years (mean age 55 years) and investigated and documented the evolution of their lesions and changes in their quality of life. Results, In all patients there was a large improvement in the clinical appearance of the lesions, the induration and the pain. Elasticity was particularly increased, not only based on clinical findings but also as documented with objective assessment. The acceptability of the treatment was good and the patients reported an improved quality of life. Conclusion, The LPG® technique (Endermology®) is an adjunctive treatment for morphea. It cannot eliminate the disease but can relieve the pain, soften the skin and improve the quality of life for these patients. [source] Elasticity of Single Poly(amido amine) DendrimersMACROMOLECULAR RAPID COMMUNICATIONS, Issue 16 2007Nikodem Tomczak Abstract An atomic force microscope in the compression mode was used to probe the nanomechanical response of single dendrimeric molecules, as well as dendrimer aggregates adsorbed on silicon surface. The force-compression behaviour of individual, generation 5 poly(amido amine) (PAMAM) dendrimers was described by a Hertzian model for the deformation of elastic bodies. The modulus values obtained ranged between 700 MPa (single dendrimers) and 150 MPa (dendrimer aggregates). [source] Protein Matrix Elasticity Determined by Fluorescence Anisotropy of Its Tryptophan Residues,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2003Christian Zentz ABSTRACT Rotational motions of Trp residues embedded within human hemoglobin matrix have been measured by using their steady-state fluorescence anisotropy. The mean square angular displacement ,2 of Trp residues, depending on the temperature, can be expressed by where W is the thermal energy acting on the Trp residues and C the resilient torque constant of the protein matrix. To study the external medium influencing the protein dynamics, comparative experiments were made with protein in aqueous buffer and in the presence of 32% glycerol. The data show that between 5°C and 25°C, external medium acts on the protein matrix elasticity. [source] Elasticity, electronic structure, and dielectric property of cubic SrHfO3 from first-principlesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 1 2009Z. F. Hou Abstract Recently, SrHfO3 compound was proposed as a potential gate dielectric to fabricate metal,oxide,semiconductor field-effect transistors (MOSFET) with equivalent oxide thickness (EOT) below 1 nm. Here we report the elasticity, electronic structure, and dielectric property of cubic SrHfO3 from first-principle study based on the plane-wave pseudopotential method within the local density approximation (LDA). The independent elastic constants of cubic SrHfO3 are derived from the derivative of total energy as a function of lattice strain. The elastic modulus is predicted from Voight-Hill bounds. The Born effective charges, electronic dielectric tensors, long wavelength phonon frequencies, and LO,TO splitting of cubic SrHfO3 are computed by linear response with density functional perturbation theory (DFPT). The calculated lattice constant and bulk modulus of cubic SrHfO3 are in good agreement with the available experimental data and other theoretical results. Our results show cubic SrHfO3 is a ductile insulator with an indirect band gap of 3.74 eV (LDA value) and electric dielectric tensor of 4.43, Hf 5d states and O 2p states exhibit a strong hybridization, and cubic SrHfO3 can be mechanically stable. In addition, the phonon frequency of ,soft mode' at zone-center also agrees well with previous theoretical value. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Relationship Between Glycosylated Hemoglobin and Arterial ElasticityPREVENTIVE CARDIOLOGY, Issue 3 2006L. Michael Prisant MD Arterial elasticity is decreased in diabetes, but it is unclear whether there is a relationship between glycosylated hemoglobin (HbA1c) and arterial elasticity. To evaluate this question, 111 subjects with diabetes mellitus had HbA1c and arterial elasticity determined in an academic outpatient setting. Three measurements of arterial elasticity indices were obtained supine using the HDI/PulseWave CR-2000 Research Cardiovascular Profiling System (Hypertension Diagnostics Inc., Eagan, MN). The study population was 49% black and 51% women. Population characteristics included age, 49.2 years; duration of diabetes, 12.1 years; HbA1c, 8.9%; large artery elasticity, 11.8 mL/mm Hg × 10; and small artery elasticity, 4.7 mL/mm Hg × 100. Age correlated with diminished large artery elasticity. Women had a lower large artery elasticity than men (10.6 vs. 13.3 mL/mm Hg × 10; p=0.0002). Decreasing small artery elasticity was associated with increasing age (p=0.0001), HbA1c (p=0.0184), and African-American ethnicity (p=0.0306). Women had less small artery elasticity than men (3.8 vs. mL/mm Hg × 100; p=0.0001). Black diabetic patients had a reduced arterial elasticity compared with whites. Increasing HbA1c is associated with decreasing small artery elasticity, but not large artery elasticity. In diabetic patients, small artery elasticity is reduced to a greater extent in women than men and in blacks than whites. [source] The Vibrational Behavior of Bladed Disks in Consideration of Friction Damping and Contact ElasticityPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2005Christian Siewert Rotating turbine blading is subjected to fluctuating gas forces during operation that cause blade vibrations. One of the main tasks in the design of turbomachinery blading is the reduction of the vibration amplitudes of the blades to avoid high resonance stresses that could damage the blading. The vibration amplitudes of the blades can be reduced significantly to a reasonable amount by means of friction damping devices such as underplatform dampers. In the case of blade vibrations, relative displacements between the friction damping devices and the neighboring blades occur and friction forces are generated that provide additional damping to the structure due to the dry friction energy dissipation. In real turbomachinery applications, spatial blade vibrations caused by a complex blade geometry and distributed excitation forces acting on the airfoil accur. Therefore, a three dimensional model including an appropriate spatial contact model to predict the generalized contact forces is necessary to describe the vibrational behavior of the blading with sufficient accuracy, see [1] and [2]. In this paper the contact model presented in [2] is extended to include also local deformations in the contacts between underplatform dampers and the contact surfaces of the adjacent blades. The additional elasticity in the contact influences the resonance frequency of the coupled bladed disk assembly. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Income Distribution, Price Elasticity and the ,Robinson Effect'THE MANCHESTER SCHOOL, Issue 5 2004Corrado Benassi In The Economics of Imperfect Competition, Joan Robinson argued that an increase of the consumers' incomes should make demand less elastic,which, although reasonable about individual demand as an assumption on preferences, suggests a role for income distribution as far as market demand is concerned. We use Esteban's (International Economic Review, Vol. 27 (1986), No. 2, pp. 439,444) income share elasticity to provide sufficient conditions on income distribution that support the ,Robinson effect',i.e. such that a negative (positive) relationship between individual income and price elasticity translates into a negative (positive) relationship between mean income and market demand elasticity. The paper also provides a framework to study the effects of distributive shocks on the price elasticity of market demand. [source] Modelling life history strategies with capture,recapture data: Evolutionary demography of the water skink Eulamprus tympanumAUSTRAL ECOLOGY, Issue 4 2001Simon P. Blomberg Abstract Matrix population models, elasticity analysis and loop analysis can potentially provide powerful techniques for the analysis of life histories. Data from a capture,recapture study on a population of southern highland water skinks (Eulamprus tympanum) were used to construct a matrix population model. Errors in elasticities were calculated by using the parametric bootstrap technique. Elasticity and loop analyses were then conducted to identify the life history stages most important to fitness. The same techniques were used to investigate the relative importance of fast versus slow growth, and rapid versus delayed reproduction. Mature water skinks were long-lived, but there was high immature mortality. The most sensitive life history stage was the subadult stage. It is suggested that life history evolution in E. tympanum may be strongly affected by predation, particularly by birds. Because our population declined over the study, slow growth and delayed reproduction were the optimal life history strategies over this period. Although the techniques of evolutionary demography provide a powerful approach for the analysis of life histories, there are formidable logistical obstacles in gathering enough high-quality data for robust estimates of the critical parameters. [source] Incorporating Uncertainty into Demographic Modeling: Application to Shark Populations and Their ConservationCONSERVATION BIOLOGY, Issue 4 2002Enric Cortés I used age-structured life tables and Leslie matrices based on a prebreeding survey and a yearly time step applied only to females to model the demography of 41 populations from 38 species of sharks representing four orders and nine families. I used Monte Carlo simulation to reflect uncertainty in the estimates of demographic traits and to calculate population statistics and elasticities for these populations; I used correlation analysis to identify the demographic traits that explained most of the variation in population growth rates ( , ). The populations I examined fell along a continuum of life-history characteristics that can be linked to elasticity patterns. Sharks characterized by early age at maturity, short lifespan, and large litter size had high , values and short generation times, whereas sharks that mature late and have long lifespans and small litters have low , values and long generation times. Sharks at the "fast" end of the spectrum tended to have comparable adult and juvenile survival elasticities, whereas sharks at the "slow" end of the continuum had high juvenile survival elasticity and low age,zero survival ( or fertility ) elasticity. Ratios of adult survival to fertility elasticities and juvenile survival to fertility elasticities suggest that many of the populations studied do not possess the biological attributes necessary to restore , to its original level after moderate levels of exploitation. Elasticity analysis suggests that changes in juvenile survival would have the greatest effect on ,, and correlation analysis indicates that variation in juvenile survival, age at maturity, and reproduction account for most of the variation in ,. In general, combined results from elasticity and correlation analyses suggest that research, conservation, and management efforts should focus on these demographic traits. Resumen: Exploré los efectos de la incertidumbre en los caracteres demográficos en análisis demográficos de tiburones, un método no empleado con anterioridad para este taxón. Utilicé tablas de vida estructuradas por edades y matrices de Leslie basadas en evaluaciones pre-gestación y pasos de tiempo de un año aplicados solo a las hembras para modelar la demografía de 41 poblaciones de 38 especies de tiburones que representan cuatro órdenes y nueve familias. Utilicé la simulación de Monte Carlo para reflejar la incertidumbre en las estimaciones de caracteres demográficos y calcular las estadísticas y elasticidades poblacionales para estas poblaciones y el análisis de correlación para identificar los caracteres demográficos que explican la mayoría de la variación en las tasas de crecimiento poblacional ( , ). Las poblaciones examinadas caen dentro de un continuo de características de historias de vida que pueden estar vinculadas con los patrones de elasticidad. Los tiburones que maduran a temprana edad y tienen corta duración de vida y grupos grandes de crías tuvieron valores altos de , y tiempos generacionales cortos, mientras que los tiburones que maduran tarde y tienen una duración de vida larga y grupos pequeños de crías tienen valores bajos de , y tiempos generacionales largos. Los tiburones que se encuentran en el punto final "rápido" del espectro tendieron a tener elasticidades de supervivencia de adultos y juveniles comparables, mientras que los tiburones en el punto final "lento" del continuo tuvieron una alta elasticidad de supervivencia de juveniles y una baja elasticidad en supervivencia a la edad cero (o fertilidad ). Las proporciones de elasticidades de supervivencia de adultos y fertilidad y de elasticidades de supervivencia de juveniles y fertilidad sugieren que muchas de las poblaciones estudiadas no poseen los atributos biológicos necesarios para restaurar , a su nivel original después de niveles moderados de explotación. El análisis de elasticidad sugiere que en la supervivencia de juveniles se podría tener el efecto mayor de , y el análisis de correlación indica que la variación en la supervivencia de juveniles, la edad de maduración y reproducción explican la mayor parte de la variación en ,. En general, los resultados combinados de los análisis de elasticidad y correlación sugieren que los esfuerzos de investigación, conservación y manejo deberían enfocarse a estas características demográficas. [source] WHO'S AFRAID OF THE MARSHALL-LERNER CONDITION?ECONOMIC PAPERS: A JOURNAL OF APPLIED ECONOMICS AND POLICY, Issue 4 2005Gordon D. Menzies The Marshall-Lerner condition,that the sum of the elasticities of import and export demand exceeds unity,has been put forward as a condition that is required for a depreciation to make the trade balance more positive. Based on recently estimated trade equations, the more appropriate condition for Australia is that the sum of the import elasticity of demand and the elasticity of the export price with respect to the exchange rate exceeds unity. I call this the Small Economy Marshall,Lerner (SEML) condition. In recent history, this condition was fulfilled in 1999,2001, when the (unstable) relationship between the terms of trade and the exchange rate broke down. [source] Effects of beverage alcohol price and tax levels on drinking: a meta-analysis of 1003 estimates from 112 studiesADDICTION, Issue 2 2009Alexander C. Wagenaar ABSTRACT Aims We conducted a systematic review of studies examining relationships between measures of beverage alcohol tax or price levels and alcohol sales or self-reported drinking. A total of 112 studies of alcohol tax or price effects were found, containing1003 estimates of the tax/price,consumption relationship. Design Studies included analyses of alternative outcome measures, varying subgroups of the population, several statistical models, and using different units of analysis. Multiple estimates were coded from each study, along with numerous study characteristics. Using reported estimates, standard errors, t -ratios, sample sizes and other statistics, we calculated the partial correlation for the relationship between alcohol price or tax and sales or drinking measures for each major model or subgroup reported within each study. Random-effects models were used to combine studies for inverse variance weighted overall estimates of the magnitude and significance of the relationship between alcohol tax/price and drinking. Findings Simple means of reported elasticities are ,0.46 for beer, ,0.69 for wine and ,0.80 for spirits. Meta-analytical results document the highly significant relationships (P < 0.001) between alcohol tax or price measures and indices of sales or consumption of alcohol (aggregate-level r = ,0.17 for beer, ,0.30 for wine, ,0.29 for spirits and ,0.44 for total alcohol). Price/tax also affects heavy drinking significantly (mean reported elasticity = ,0.28, individual-level r = ,0.01, P < 0.01), but the magnitude of effect is smaller than effects on overall drinking. Conclusions A large literature establishes that beverage alcohol prices and taxes are related inversely to drinking. Effects are large compared to other prevention policies and programs. Public policies that raise prices of alcohol are an effective means to reduce drinking. [source] The income elasticity of tax revenue: estimates for income and consumption taxes in the United KingdomFISCAL STUDIES, Issue 1 2004John Creedy Abstract This paper provides estimates of individual and aggregate revenue elasticities of income and consumption taxes in the UK over the period 1989,2000. It shows how budgetary changes, including changes to income-related deductions, have substantially affected income elasticities. The estimates of consumption tax revenue elasticities show that changes in consumption patterns over time are important. A merit of the approach used here is that elasticity estimates can be calculated readily from official published sources. [source] Falling Labor Share and Rising Unemployment: Long,Run Consequences of Institutional Shocks?GERMAN ECONOMIC REVIEW, Issue 4 2002Norbert Berthold The literature on unemployment has mostly focused on labor market issues while the impact of capital formation is largely neglected. Job creation is often thought to be a matter of encouraging more employment on a given capital stock. In contrast, this paper explicitly deals with the long,run consequences of institutional shocks on capital formation and employment. It is shown that the usual tradeoff between employment and wages disappears in the long run. In line with an appropriation model, the estimated values for the long,run elasticities of substitution between capital and labor for Germany and France are substantially greater than one. [source] Labour Mobility: An Adjustment Mechanism in Euroland?GERMAN ECONOMIC REVIEW, Issue 2 2001Empirical Evidence for Western Germany, France, Italy We evaluate whether labour mobility is likely to act as a sufficient adjustment mechanism in the face of asymmetric shocks in Euroland. As no adequate data on cross-border migration are available, migration elasticities within nation states (Western Germany, France and Italy) are estimated and interpreted as upper bounds for cross-border migration elasticities between European nation states. Labour mobility is highest in Germany, followed by France and Italy. However, the accommodation of a shock to unemployment by migration takes several years. We conclude that labour mobility is unlikely to act as a sufficient adjustment mechanism to asymmetric shocks in Euroland. [source] The effects of pay and job satisfaction on the labour supply of hospital consultantsHEALTH ECONOMICS, Issue 12 2007Divine Ikenwilo Abstract There is little evidence about the responsiveness of doctors' labour supply to changes in pay. Given substantial increases in NHS expenditure, new national contracts for hospital doctors and general practitioners that involve increases in pay, and the gradual imposition of a ceiling on hours worked through the European Working Time Directive, knowledge of the size of labour supply elasticities is crucial in examining the effects of these major changes. This paper estimates a modified labour supply model for hospital consultants, using data from a survey of consultants in Scotland. Rigidities in wage setting within the NHS mean that the usual specification of the labour supply model is extended by the inclusion of job quality (job satisfaction) in the equation explaining the optimal number of hours worked. Generalised Method of Moments estimation is used to account for the endogeneity of both earnings and job quality. Our results confirm the importance of pay and non-pay factors on the supply of labour by consultants. The results are sensitive to the exclusion of job quality and show a slight underestimation of the uncompensated earnings elasticity (of 0.09) without controlling for the effect of job quality, and 0.12 when we controlled for job quality. Pay increases in the new contract for consultants will only result in small increases in hours worked. Small and non-significant elasticity estimates at higher quantiles in the distribution of hours suggest that any increases in hours worked are more likely for consultants who work part time. Those currently working above the median number of hours are much less responsive to changes in earnings. Copyright © 2007 John Wiley & Sons, Ltd. [source] Elasticities of market shares and social health insurance choice in germany: a dynamic panel data approachHEALTH ECONOMICS, Issue 3 2007Marcus Tamm Abstract In 1996, free choice of health insurers was introduced to the German social health insurance system. One objective was to increase efficiency through competition. A crucial precondition for effective competition among health insurers is that consumers search for lower-priced health insurers. We test this hypothesis by estimating the price elasticities of insurers' market shares. We use unique panel data and specify a dynamic panel model to explain changes in market shares. Estimation results suggest that short-run price elasticities are smaller than previously found by other studies. In the long-run, however, estimation results suggest substantial price effects. 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