Shifted loops and coercivity from field imprinted high energy barriers in ferritin and ferrihydrite nanoparticles

We show that the coercive field in ferritin and ferrihydrite depends on the maximum magnetic field in a hysteresis loop and that coercivity and loop shifts depend both on the maximum and cooling fields. In the case of ferritin, we show that the time dependence of the magnetization also depends on the maximum and previous cooling fields. This behavior is associated to changes in the intraparticle energy barriers imprinted by these fields. Accordingly, the dependence of the coercive and loop-shift fields with the maximum field in ferritin and ferrihydrite can be described within the frame of a uniform-rotation model considering a dependence of the energy barrier with the maximum and the cooling fields.

Pareto-improving optimal capital and labor taxes

We show a standard model where the optimal tax reform is to cut labor taxes and leave capital taxes very high in the short and medium run. Only in the very long run would capital taxes be zero. Our model is a version of Chamley??s, with heterogeneous agents, without lump sum transfers, an upper bound on capital taxes, and a focus on Pareto improving plans. For our calibration labor taxes should be low for the first ten to twenty years, while capital taxes should be at their maximum. This policy ensures that all agents benefit from the tax reform and that capital grows quickly after when the reform begins. Therefore, the long run optimal tax mix is the opposite from the short and medium run tax mix. The initial labor tax cut is financed by deficits that lead to a positive long run level of government debt, reversing the standard prediction that government accumulates savings in models with optimal capital taxes. If labor supply is somewhat elastic benefits from tax reform are high and they can be shifted entirely to capitalists or workers by varying the length of the transition. With inelastic labor supply there is an increasing part of the equilibrium frontier, this means that the scope for benefitting the workers is limited and the total benefits from reforming taxes are much lower.

Changes in the demand for private medical insurance following a shift in tax incentives

The 1998 Spanish reform of the Personal Income Tax eliminated the 15% deduction for private medical expenditures including payments on private health insurance (PHI) policies. To avoid an undesirable increase in the demand for publicly funded health care, tax incentives to buy PHI were not completely removed but basically shifted from individual to group employer-paid policies. In a unique fiscal experiment, at the same time that the tax relief for individually purchased policies was abolished, the government provided for tax allowances on policies taken out through employment. Using a bivariate probit model on data from National Health Surveys, we estimate the impact of said reform on the demand for PHI and the changes occurred within it. Our findings suggest that the total probability of buying PHI was not significantly affected. Indeed, the fall in the demand for individual policies (by 10% between 1997 and 2001) was offset by an increase in the demand for group employer-paid ones, so that the overall size of the market remained virtually unchanged. We also briefly discuss the welfare effects on the state budget, the industry and society at large.

Diseño cooperativo de un sistema de comunicaciones por satélite basado en diversidad espacial

En este proyecto se han presentado los modelos de distribución de canal más comunes que se puede encontrar una señal en una transmisión. Seguidamente se ha presentado el concepto de diversidad en comunicaciones inalámbricas terrestres y se ha trasladado el escenario a comunicaciones por satélite. Para analizar la calidad de los enlaces con diversidad se ha realizado un simulador, con Matlab, que modele la estructura básica de un sistema de comunicaciones (emisor, canal y receptor). Simulando las comunicaciones entre los diferentes sistemas de diversidad se ha podido comparar la calidad de cada enlace. El modelo Alamouti ha presentado una robustez y una baja probabilidad de error que hacen que sea la mejor elección a la hora de diseñar un sistema de diversidad para comunicaciones por satélite. Utiliza la diversidad de canal para aprovechar cada pizca de señal que recibe y así poder descifrar el mensaje enviado.

Composición en ácidos grasos de huevos y larvas de dentón (Dentex dentex L.) de hasta 40 días en condiciones de cultivo

Total lipid content and fatty acid (FA) composition of common dentex eggs spawned at different times and larvae reared under different culture conditions until 40 days post hatch (dph) were analysed in order to get a general pattern of lipid composition during larval development. Results were grouped according to the developmental stage of the larvae instead of age in dph. Saturated and monounsaturated fatty acids decreased along larval development, while polyunsaturated fatty acid (PUFA) content increased. The ratio of docosahexaenoic acid (DHA) / eicosapentaenoic acid (EPA) shifted from 4 – 5 in early developmental stages to lower than 1 after metamorphosis. Results suggest a subdivision of the larval development into two stages of opposite FA requirements.

Síntesi i estudi de les propietats de fotoluminescència de nanoestructures de sulfur de cadmi

S’han sintetitzat estructures de CdS a partir de sílice mesoporosa (SBA-15, SBA-16 i KIT-6) pel mètode del motlle rígid i s’han caracteritzat mitjançant TEM i XRD, i se n’han estudiat les seves propietats de fotoluminescència mitjançant CSLM. Els resultats obtinguts s’han comparat amb una mostra de CdS comercial. El CdS SBA-15 ha conservat l’estructura mesoporosa del motlle, mentre que en els altres dos casos s’ha mantingut només de manera parcial. Per a totes les mostres, la mida de partícula es troba en el rang dels 3-10 nm. Pel que fa a l’estructura, s’ha detectat fase wurtzita i zinc-blenda, en diferents percentatges entre elles. La formació de wurtzita pot ser en part responsable del col·lapse parcial de la mesostructura. El pic de màxima emissió en l’espectre de fotoluminescència es desplaça entre les diferents estructures segons la mida de partícula. L’amplada del pic varia en funció del grau de dispersió de partícula, de manera que s’observa que aquesta és inferior en les mostres sintetitzades respecte de la comercial.

Estudio y construcción de herramientas de validación HTML

The Final Year Project consists of two essentially different parts, which share acommon theme: HTML code validation. The first of these two parts focuses on the study of the validation process. It supplies a brief introduction to the evolution of HTML and XHTML, the new tags introduced in HTML5 and the most common errors found in today's websites. Already developed HTML validation tools are analyzed and examined in detail in order to compare their features and evaluate their performances. Lastly, a comparison of the parsing process in the most common browsers found nowadays is provided. In the second part of the project the focus of the project is shifted towards the development of a XHTML5 validation tool. The input is a XHTML5 file whose content may or may not comply with the W3C specification, and therefore, may or may not be a valid XHTML5 document. The output provided by this tool will be a fixed XHTML5 document and an error log returned in the form of a XML file. Information as to the course of action pursued to fix the error and its location will also be included.

Analysis of Pleistocene paleodrainage evolution in the Po Basin (Italy) by multivariate statistical techniques

In order to obtain a high-resolution Pleistocene stratigraphy, eleven continuouslycored boreholes, 100 to 220m deep were drilled in the northern part of the PoPlain by Regione Lombardia in the last five years. Quantitative provenanceanalysis (QPA, Weltje and von Eynatten, 2004) of Pleistocene sands was carriedout by using multivariate statistical analysis (principal component analysis, PCA,and similarity analysis) on an integrated data set, including high-resolution bulkpetrography and heavy-mineral analyses on Pleistocene sands and of 250 majorand minor modern rivers draining the southern flank of the Alps from West toEast (Garzanti et al, 2004; 2006). Prior to the onset of major Alpine glaciations,metamorphic and quartzofeldspathic detritus from the Western and Central Alpswas carried from the axial belt to the Po basin longitudinally parallel to theSouthAlpine belt by a trunk river (Vezzoli and Garzanti, 2008). This scenariorapidly changed during the marine isotope stage 22 (0.87 Ma), with the onset ofthe first major Pleistocene glaciation in the Alps (Muttoni et al, 2003). PCA andsimilarity analysis from core samples show that the longitudinal trunk river at thistime was shifted southward by the rapid southward and westward progradation oftransverse alluvial river systems fed from the Central and Southern Alps.Sediments were transported southward by braided river systems as well as glacialsediments transported by Alpine valley glaciers invaded the alluvial plain.Kew words: Detrital modes; Modern sands; Provenance; Principal ComponentsAnalysis; Similarity, Canberra Distance; palaeodrainage

Modification of the Perrine-Baum diagram to improve the calculation of high voltage electric lines

Through the history of Electrical Engineering education, vectorial and phasorial diagrams have been used as a fundamental learning tool. At present, computational power has replaced them by long data lists, the result of solving equation systems by means of numerical methods. In this sense, diagrams have been shifted to an academic background and although theoretically explained, they are not used in a practical way within specific examples. This fact may be against the understanding of the complex behavior of the electrical power systems by students. This article proposes a modification of the classical Perrine-Baum diagram construction to allowing both a more practical representation and a better understanding of the behavior of a high-voltage electric line under different levels of load. This modification allows, at the same time, the forecast of the obsolescence of this behavior and line’s loading capacity. Complementary, we evaluate the impact of this tool in the learning process showing comparative undergraduate results during three academic years

From severance pay to self-insurance: Effects of severance payments savings accounts in Colombia

In 1990 Colombia replaced its traditional system of severance paymentswith a new system of severance payments savings accounts (SPSAs). Althoughseverance payments often are justified on the grounds that they provideinsurance against earnings loss, they also increase costs for employersand distort employment decisions. The impact of severance payments dependslargely on how much of the costs to employers can be shifted to workers.The theoretical analysis in this paper shows that, in contrast to atraditional system of severance payments, the system of SPSAs facilitatesthe shifting of severance payments costs to workers in the form of lowerwages. Empirical results using the Colombian National Household Surveysindicate that the introduction of SPSAs shifted around 80% of the totalseverance payments contributions to wages and had a positive effect onweekly hours. Results using the 1997 Colombian Living Standards MeasurementSurvey suggest that, although SPSAs in part replaced employer insurancewith self-insurance, SPSAs continue to play a consumption smoothing rolefor the non-employed.

Explaining movements in the labor share

In this paper we study the evolution of the labor share in the OECD since 1970. We show it is essentially related to the capital-output ratio; that this relationship is shifted by factors like the price of imported materials or the skill mix; and that discrepancies between the marginal product of labor and the real wage (due to, e.g., product market power, union bargaining, and labor adjustment costs) cause departures from it. We provide estimates of the model with panel data on 14 industries and 14 countries for 1973-93 and use them to compute the evolution of the wage gap in Germany and the US.

Killing by lung cancer or by diabetes? The trade-off between smoking and obesity

As the prevalence of smoking has decreased to below 20%, health practitioners interest has shifted towards theprevalence of obesity, and reducing it is one of the major health challenges in decades to come. In this paper westudy the impact that the final product of the anti-smoking campaign, that is, smokers quitting the habit, had onaverage weight in the population. To these ends, we use data from the Behavioral Risk Factors Surveillance System,a large series of independent representative cross-sectional surveys. We construct a synthetic panel that allows us tocontrol for unobserved heterogeneity and we exploit the exogenous changes in taxes and regulations to instrumentthe endogenous decision to give up the habit of smoking. Our estimates, are very close to estimates issued in the 90sby the US Department of Health, and indicate that a 10% decrease in the incidence of smoking leads to an averageweight increase of 2.2 to 3 pounds, depending on choice of specification. In addition, we find evidence that the effectovershoots in the short run, although a significant part remains even after two years. However, when we split thesample between men and women, we only find a significant effect for men. Finally, the implicit elasticity of quittingsmoking to the probability of becoming obese is calculated at 0.58. This implies that the net benefit from reducingthe incidence of smoking by 1% is positive even though the cost to society is $0.6 billions.

The labor market effects of payroll taxes in a middle-income country: Evidence from Colombia

We use a panel of manufacturing plants from Colombia to analyze how the risein payroll tax rates over the 1980 s and 1990 s affected the labor market.Our estimates indicate that formal wages fall by between 1.4% and 2.3% as aresult of a 10% rise in payroll taxes. This 'less-than-full-shifting' islikely to be the result of weak linkages between benefits and taxes and thepresence of downward wage rigidities induced by a binding minimum wage inColombia. Because the costs of taxation are only partly shifted fromemployers to employees, employment should also fall. Our results indicatethat a 10% increase in payroll taxes lowered formal employment by between4% and 5%. In addition, we find less shifting and larger disemploymenteffects for production than non-production workers. These results suggestthat policies aimed at boosting the relative demand of low-skill workers byreducing social security taxes on those with low earnings may be effectivein a country like Colombia, especially if tax cuts are targeted to indirectbenefits.

New measurements of radial velocities in clusters of galaxies

Redshifts for 100 galaxies in 10 clusters of galaxies are presented based on data obtained between March 1984 and March 1985 from Calar Alto, La Palma, and ESO, and on data from Mauna Kea. Data for individual galaxies are given, and the accuracy of the velocities of the four instruments is discussed. Comparison with published data shows the present velocities to be shifted by + 4.0 km/s on average, with a standard deviation in the difference of 89.7 km/s, consistent with the rms of redshift measurements which range from 50-100 km/s.

K-Rb Fermi-Bose mixtures: Vortex states and sag

We study a confined mixture of bosons and fermions in the quantal degeneracy regime with attractive boson-fermion interaction. We discuss the effect that the presence of vortical states and the displacement of the trapping potentials may have on mixtures near collapse, and investigate the phase stability diagram of the K-Rb mixture in the mean-field approximation supposing in one case that the trapping potentials felt by bosons and fermions are shifted from each other, as it happens in the presence of a gravitational sag, and in another case, assuming that the Bose condensate sustains a vortex state. In both cases, we have obtained an analytical expression for the fermion effective potential when the Bose condensate is in the Thomas-Fermi regime, that can be used to determine the maxima of the Fermionic density. We have numerically checked that the values one obtains for the location of these maxima using the analytical formulas remain valid up to the critical boson and fermion numbers, above which the mixture collapses.