Implementació d'un sistema de compressió de dades en el dispositiu mota Cou24 sota TinyOS.

Les limitacions en la capacitat d'emmagatzemament dels dispositius sensors sense fils o motes és consubstancial al seu disseny, però pot convertir-se en un problema en determinades situacions. Aquest projecte de fi de carrera ha esta motivat per l'interès en superar aquestes limitacions en una situació concreta: una mota dedicada a prendre mostres amb alguns dels seus sensors que passa un període llarg de temps sense poder comunicar amb la base. Per aconseguir aquest objectiu s'ha dissenyat i implementat un sistema que comprimeix les mostres en una mota només quan l'espai d'emmagatzemament està pròxim a exhaurir-se. Aquest procés de compressió pot repetir-se indefinidament i cada vegada que actua elimina només les mostres menys significatives, tot preservant la freqüència del mostreig.A continuació es descriu l'algorisme que s'ha dissenyat, respectuós amb les capacitats de processament de la mota, la implementació que s'ha fet en nesC per a una mota Cou24 amb TinyOS, el programari complementari que s'ha desenvolupat en Java per a PC, i el resultat de les proves que s'han fet de tot aquest conjunt.

Indicadores clínicos e pré-hospitalares de sobrevivência no trauma fechado: uma análise multivariada

O objetivo do estudo foi identificar os indicadores clínicos e pré-hospitalares associados à sobrevivência de vítimas de trauma fechado. Foram utilizadas a análise de sobrevivência de Kaplan Meier, e de Riscos Proporcionais de Cox, para analisar a associação de 33 variáveis ao óbito precoce e tardio, propondo modelos multivariados. Os modelos finais até 48h pós-trauma evidenciaram altos coeficientes de risco promovidos pelas lesões abdominais, Injury Severity Score >25, procedimentos respiratórios avançados e compressões torácicas pré-hospitalares. No modelo até 7 dias, a pressão arterial sistólica na cena do acidente, se menor de 75mmHg, foi associada a maior risco de óbito e se ausente, foi associada ao mais elevado risco de óbito após 7 dias. A reposição de volume pré-hospitalar apresentou efeito protetor em todos os períodos. Os resultados sugerem que a magnitude da hipoxemia e da instabilidade hemodinâmica diante da hemorragia, influenciaram de forma significante o óbito precoce e tardio desse grupo de vítimas.

Education, growth and income inequality

Estimates of the e¤ect of education on GDP (the social return to education)have been hard to reconcile with micro evidence on the private return. We present a simple explanation that combines two ideas: imperfect substitution between worker types and endogenous skill biased technological progress. When types of workers are imperfect substitutes, the supply of human capital is negatively related to its return, and a higher education level compresses wage di¤erentials. We use cross-country panel data on income inequality to estimate the private return and GDP data to estimate the social return. The results show that the private return falls by 2 percentage points when the average education level increases by a year, which is consistent with Katz and Murphy's [1992] estimate of the elasticity of substitution between worker types. We find no evidence for dynamics in the private return, and certainly not for a reversal of the negative e¤ect as described in Acemoglu [2002]. The short run social return equals the private return.

Alterações estruturais e mecânicas de solo de várzea cultivado com arroz irrigado por inundação

A conversão de área natural para área de uso agrícola pode degradar a estrutura do solo, favorecendo a ocorrência de compactação. Este trabalho teve por objetivo avaliar as alterações nas propriedades físico-hídricas e mecânicas de um Gleissolo Háplico provocadas pela conversão de um campo natural antropizado para área de cultivo de arroz irrigado. Propriedades físico-hídricas (densidade, porosidade total, macro e microporosidade, índice de vazios e retenção de água) e mecânicas (pressão de preconsolidação, índice de compressão, coeficiente de descompressão e índice de recuperação) foram avaliadas nos horizontes A1 (0,0-0,25 m), A2 (0,25-0,51 m), Cg1 (0,51-0,92 m) e Cg2 (0,92-1,20+ m) em solo sob campo antropizado sem uso agrícola e nos horizontes Ap (0,0-0,17 m), A (0,17-0,40 m), Cg1 (0,40-0,70 m) e Cg2 (0,70-1,00+ m), em solo cultivado com arroz irrigado. Oito anos de cultivo de arroz sob preparo convencional e irrigação por inundação não alteraram significativamente as propriedades físico-hídricas e mecânicas, de acordo com a análise de agrupamentos. Porém, o cultivo de arroz aumentou a densidade do solo e reduziu o índice de vazios, a porosidade total e a macroporosidade. A relação da elasticidade com a densidade do solo, a porosidade total e o índice de vazios foi influenciada pelo tipo de estrutura, pois maiores compressões e descompressões ocorreram nos horizontes de estrutura prismática, em comparação aos horizontes de estrutura maciça.

Totally implantable robot to treat chronic atrial fibrillation

Chronic atrial fibrillation affects millions of people worldwide. Its surgical treatment often fails to restore the transport function of the atrium. This study first introduces the concept of an atrial assist device (AAD) to restore the pump function of the atrium. The AAD is developed to be totally implantable in the human body with a transcutaneous energy transfer system to recharge the implanted battery. The ADD consists of a motorless pump based on artificial muscle technology, positioned on the external surface of the atrium to compress it and restore its muscular activity. A bench model reproduces the function of a fibrillating atrium to assess the circulatory support that this pump can provide. Atripump (Nanopowers SA, Switzerland) is a dome-shaped silicone-coated nitinol actuator 5 mm high, sutured on the external surface of the atrium. A pacemaker-like control unit drives the actuator that compresses the atrium, providing the mechanical support to the blood circulation. Electrical characteristics: the system is composed of one actuator that needs a minimal tension of 15 V and has a maximum current of 1.5 A with a 50% duty cycle. The implantable rechargeable battery is made of a cell having the following specifications: nominal tension of a cell: 4.1 V, tension after 90% of discharge: 3.5 V, nominal capacity of a cell: 163 mA h. The bench model consists of an open circuit made of latex bladder 60 mm in diameter filled with water. The bladder is connected to a vertically positioned tube that is filled to different levels, reproducing changes in cardiac preload. The Atripump is placed on the outer surface of the bladder. Pressure, volume and temperature changes were recorded. The contraction rate was 1 Hz with a power supply of 12 V, 400 mA for 200 ms. Preload ranged from 15 to 21 cm H(2)O. Maximal silicone membrane temperature was 55 degrees C and maximal temperature of the liquid environment was 35 degrees C. The pump produced a maximal work of 16 x 10(-3) J. Maximal volume pumped was 492 ml min(-1). This artificial muscle pump is compact, follows the Starling law and reproduces the hemodynamic performances of a normal atrium. It could represent a new tool to restore the atrial kick in persistent atrial fibrillation.

Computational Analysis and Optimization of Real Gas Flow In Small Centrifugal Compressors

Small centrifugal compressors are more and more widely used in many industrialsystems because of their higher efficiency and better off-design performance comparing to piston and scroll compressors as while as higher work coefficient perstage than in axial compressors. Higher efficiency is always the aim of the designer of compressors. In the present work, the influence of four partsof a small centrifugal compressor that compresses heavy molecular weight real gas has been investigated in order to achieve higher efficiency. Two parts concern the impeller: tip clearance and the circumferential position of the splitter blade. The other two parts concern the diffuser: the pinch shape and vane shape. Computational fluid dynamics is applied in this study. The Reynolds averaged Navier-Stokes flow solver Finflo is used. The quasi-steady approach is utilized. Chien's k-e turbulence model is used to model the turbulence. A new practical real gas model is presented in this study. The real gas model is easily generated, accuracy controllable and fairly fast. The numerical results and measurements show good agreement. The influence of tip clearance on the performance of a small compressor is obvious. The pressure ratio and efficiency are decreased as the size of tip clearance is increased, while the total enthalpy rise keeps almost constant. The decrement of the pressure ratio and efficiency is larger at higher mass flow rates and smaller at lower mass flow rates. The flow angles at the inlet and outlet of the impeller are increased as the size of tip clearance is increased. The results of the detailed flow field show that leakingflow is the main reason for the performance drop. The secondary flow region becomes larger as the size of tip clearance is increased and the area of the main flow is compressed. The flow uniformity is then decreased. A detailed study shows that the leaking flow rate is higher near the exit of the impeller than that near the inlet of the impeller. Based on this phenomenon, a new partiallyshrouded impeller is used. The impeller is shrouded near the exit of the impeller. The results show that the flow field near the exit of the impeller is greatly changed by the partially shrouded impeller, and better performance is achievedthan with the unshrouded impeller. The loading distribution on the impeller blade and the flow fields in the impeller is changed by moving the splitter of the impeller in circumferential direction. Moving the splitter slightly to the suction side of the long blade can improve the performance of the compressor. The total enthalpy rise is reduced if only the leading edge of the splitter ismoved to the suction side of the long blade. The performance of the compressor is decreased if the blade is bended from the radius direction at the leading edge of the splitter. The total pressure rise and the enthalpy rise of thecompressor are increased if pinch is used at the diffuser inlet. Among the fivedifferent pinch shape configurations, at design and lower mass flow rates the efficiency of a straight line pinch is the highest, while at higher mass flow rate, the efficiency of a concave pinch is the highest. The sharp corner of the pinch is the main reason for the decrease of efficiency and should be avoided. The variation of the flow angles entering the diffuser in spanwise direction is decreased if pinch is applied. A three-dimensional low solidity twisted vaned diffuser is designed to match the flow angles entering the diffuser. The numerical results show that the pressure recovery in the twisted diffuser is higher than in a conventional low solidity vaned diffuser, which also leads to higher efficiency of the twisted diffuser. Investigation of the detailed flow fields shows that the separation at lower mass flow rate in the twisted diffuser is later than in the conventional low solidity vaned diffuser, which leads to a possible wider flow range of the twisted diffuser.

Experimental insights into deformation dynamics and intermittency in rapid granular shear flows

This work concerns the experimental study of rapid granular shear flows in annular Couette geometry. The flow is induced by continuous driving of the horizontal plate at the top of the granular bed in an annulus. The compressive pressure, driving torque, instantaneous bed height and rotational speed of the shearing plate are measured. Moreover, local stress fluctuations are measured in a medium made of steel spheres 2 and 3 mm in diameter. Both monodisperse packing and bidisperse packing are investigated to reveal the influence of size diversity in intermittent features of granular materials. Experiments are conducted in an annulus that can contain up to 15 kg of spherical steel balls. The shearing granular medium takes place via the rotation of the upper plate which compresses the material loaded inside the annulus. Fluctuations of compressive force are locally measured at the bottom of the annulus using a piezoelectric sensor. Rapid shear flow experiments are pursued at different compressive forces and shear rates and the sensitivity of fluctuations are then investigated by different means through monodisperse and bidisperse packings. Another important feature of rapid granular shear flows is the formation of ordered structures upon shearing. It requires a certain range for the amount of granular material (uniform size distribution) loaded in the system in order to obtain stable flows. This is studied more deeply in this thesis. The results of the current work bring some new insights into deformation dynamics and intermittency in rapid granular shear flows. The experimental apparatus is modified in comparison to earlier investigations. The measurements produce data for various quantities continuously sampled from the start of shearing to the end. Static failure and dynamic shearing ofa granular medium is investigated. The results of this work revealed some important features of failure dynamics and structure formation in the system. Furthermore, some computer simulations are performed in a 2D annulus to examine the nature of kinetic energy dissipation. It is found that turbulent flow models can statistically represent rapid granular flows with high accuracy. In addition to academic outcomes and scientific publications our results have a number of technological applications associated with grinding, mining and massive grain storages.

Use of alternative and complementary therapies in labor and delivery care: a cross-sectional study of midwives" training in Catalan hospitals accredited as centers for normal birth

Background: The use of complementary and alternative medicine (CAM) and complementary and alternative therapies (CAT) during pregnancy is increasing. Scientific evidence for CAM and CAT in the field of obstetrics mainly covers pain relief in labor. Midwives are responsible for labor and delivery care: hence, their knowledge of CAM and CAT is important. The aims of this study are to describe the professional profile of midwives who provide care for natural childbirth in Catalan hospitals accredited as centers for normal birth, to assess midwives" level of training in CAT and their use of these therapies, and to identify specific resources for CAT in labor wards. Methods: A descriptive, cross-sectional, quantitative method was used to assess the level of training and use of CAT by midwives working at 28 hospitals in Catalonia, Spain, accredited as public normal birth centers. Results: Just under a third of midwives (30.4%) trained in CAT after completion of basic training. They trained in an average of 5.97 therapies (SD 3.56). The number of CAT in which the midwives were trained correlated negatively with age (r = - 0.284; p < 0.001) and with their time working at the hospital in years (r = - 0.136; p = 0.036). Midwives trained in CAT considered that the following therapies were useful or very useful for pain relief during labor and delivery: relaxation techniques (64.3%), hydrotherapy (84.8%) and the application of compresses to the perineum (75.9%). The availability of resources for providing CAT during normal birth care varied widely from center to center. Conclusions: Age may influence attitudes towards training. It is important to increase the number of midwives trained in CAM for pain relief during childbirth, in order to promote the use of CAT and ensure efficiency and safety. CAT resources at accredited hospitals providing normal childbirth care should also be standardized.

Use of alternative and complementary therapies in labor and delivery care: a cross-sectional study of midwives" training in Catalan hospitals accredited as centers for normal birth

Background: The use of complementary and alternative medicine (CAM) and complementary and alternative therapies (CAT) during pregnancy is increasing. Scientific evidence for CAM and CAT in the field of obstetrics mainly covers pain relief in labor. Midwives are responsible for labor and delivery care: hence, their knowledge of CAM and CAT is important. The aims of this study are to describe the professional profile of midwives who provide care for natural childbirth in Catalan hospitals accredited as centers for normal birth, to assess midwives" level of training in CAT and their use of these therapies, and to identify specific resources for CAT in labor wards. Methods: A descriptive, cross-sectional, quantitative method was used to assess the level of training and use of CAT by midwives working at 28 hospitals in Catalonia, Spain, accredited as public normal birth centers. Results: Just under a third of midwives (30.4%) trained in CAT after completion of basic training. They trained in an average of 5.97 therapies (SD 3.56). The number of CAT in which the midwives were trained correlated negatively with age (r = - 0.284; p < 0.001) and with their time working at the hospital in years (r = - 0.136; p = 0.036). Midwives trained in CAT considered that the following therapies were useful or very useful for pain relief during labor and delivery: relaxation techniques (64.3%), hydrotherapy (84.8%) and the application of compresses to the perineum (75.9%). The availability of resources for providing CAT during normal birth care varied widely from center to center. Conclusions: Age may influence attitudes towards training. It is important to increase the number of midwives trained in CAM for pain relief during childbirth, in order to promote the use of CAT and ensure efficiency and safety. CAT resources at accredited hospitals providing normal childbirth care should also be standardized.

Aplicação de danos mecânicos em abacates e seus efeitos na qualidade dos frutos

Este trabalho teve por objetivo avaliar o efeito da aplicação de danos mecânicos por impacto, compressão e corte em abacates 'Geada'. O trabalho consistiu em duas etapas: na primeira, o impacto foi aplicado deixando-se os frutos caírem, em queda livre, de 1,5 m a 3,0 m, com intervalo de 0,5 m; na compressão, os frutos sofreram a ação dos pesos: 6 kg por 12 horas e 12 kg por 6 horas. Para os cortes, foram realizados quatro cortes com 80 mm de comprimento e 4 mm de profundidade. Na segunda etapa, para a compressão, utilizou-se peso de 12 kg por tempo maior (24 h). No impacto, foi aplicada queda de 2,0 m, e os cortes, realizados da mesma maneira que na primeira etapa. Os efeitos de cada dano foram avaliados nos frutos armazenados sob condição ambiente quanto à coloração, perda de massa fresca e teores de sólidos solúveis e de acidez titulável. Queda de alturas maiores que 2,0 m levaram os frutos a rachaduras. Até 2,0 m de altura, formaram-se fissuras ao redor do caroço, que foram preenchidas por filamentos de aspecto duro e não se tornou visível externamente. O abacate não se mostrou suscetível à aplicação das compressões 6 kg/12 h e 12 kg/6 h, mas o tratamento 12 kg/24 h fez com que a casca apresentasse coloração verde mais escura durante três dias. Os cortes provocaram cicatrizes na casca.

Measurement of forces between and within bilayers of neutral phospholipids

Phospholipids in water form lamellar phases made up of alternating layers of water and bimolecular lipid leaflets. Three complementary methods, osmotic, mechanical, and vapour pressures, were used to measure the work of removing water from lamellar phases composed of frozen dipalmitoylphosphatidylcholine ( DPPC ), melted DPPC, egg phosphatidylethanolamine or equimolar mixtures of DPPC and cholesterol ( DPPC/CHOL ), Concurrently the structural changes that resulted from this water removal were measured using X-ray diffraction. The work was divided into that which forces the bilayers together ( F ) and that which compresses the molecules together within the bilayers ( F )# A large repulsive force exists between bilayers composed of each of the lipids studied and this force increases exponentially as bilayer separation is decreased. F is affected by the nature of the head groups, conformation of the acyl chains and heterogeneity of these chains. In general all of the melted phosphatidylcholines ( melted DPPC, egg lecithin and DPPC/CHOL ) have large equilibrium separations in excess water resulting from large repulsive hydration forces between these bilayers. By comparison, egg PE has an increased attractive force, and frozen DPPC has a decreased hydration force; each results in smaller separations in water for these two lipids. The chemical potentials of the water between the bilayers for all these lipids lie on a continuum, indicating that interbilayer water cannot be characterized by two discrete states, usually referred to as "bound" or "non**bound". For all lipids studied a maximum of 25 % of the total work done on the system goes into deforming the bilayers. The method used here viii to separate repulsion from deformation, developed for us by v. A. Parsegian, provides a unique method for the measurement of lateral pressure of a bilayer and its modulus of deformability ( Y ). Lateral pressure is affected by the nature of the head group, conformation and heterogeneity of the acyl chains. For small changes in molecular surface area ( A ) near equilibrium, both melted and frozen DPPC have similar values for the deformability modulus. Thus in this regime it requires about the same force to change the angle of tilt of frozen chains as it does to compress the fluid bilayer. The introduction of cholesterol into bilayers of DPPC reduces dramatically the lateral pressure of the bilayers over a large range of molecular surface areas ( A ). The variation in the magnitude of bilayer repulsion with different phospholipids provides a basis for the mechanism of lipid segregation in mixed lipid systems and suggests that interacting heterogeneous membranes may influence or modulate the composition of the opposing membrane. The measurements of deformabilities of bilayers provides a direct comparison of them with the properties of monolayers.

Les algorithmes de haute résolution en tomographie d'émission par positrons : développement et accélération sur les cartes graphiques

La tomographie d’émission par positrons (TEP) est une modalité d’imagerie moléculaire utilisant des radiotraceurs marqués par des isotopes émetteurs de positrons permettant de quantifier et de sonder des processus biologiques et physiologiques. Cette modalité est surtout utilisée actuellement en oncologie, mais elle est aussi utilisée de plus en plus en cardiologie, en neurologie et en pharmacologie. En fait, c’est une modalité qui est intrinsèquement capable d’offrir avec une meilleure sensibilité des informations fonctionnelles sur le métabolisme cellulaire. Les limites de cette modalité sont surtout la faible résolution spatiale et le manque d’exactitude de la quantification. Par ailleurs, afin de dépasser ces limites qui constituent un obstacle pour élargir le champ des applications cliniques de la TEP, les nouveaux systèmes d’acquisition sont équipés d’un grand nombre de petits détecteurs ayant des meilleures performances de détection. La reconstruction de l’image se fait en utilisant les algorithmes stochastiques itératifs mieux adaptés aux acquisitions à faibles statistiques. De ce fait, le temps de reconstruction est devenu trop long pour une utilisation en milieu clinique. Ainsi, pour réduire ce temps, on les données d’acquisition sont compressées et des versions accélérées d’algorithmes stochastiques itératifs qui sont généralement moins exactes sont utilisées. Les performances améliorées par l’augmentation de nombre des détecteurs sont donc limitées par les contraintes de temps de calcul. Afin de sortir de cette boucle et permettre l’utilisation des algorithmes de reconstruction robustes, de nombreux travaux ont été effectués pour accélérer ces algorithmes sur les dispositifs GPU (Graphics Processing Units) de calcul haute performance. Dans ce travail, nous avons rejoint cet effort de la communauté scientifique pour développer et introduire en clinique l’utilisation des algorithmes de reconstruction puissants qui améliorent la résolution spatiale et l’exactitude de la quantification en TEP. Nous avons d’abord travaillé sur le développement des stratégies pour accélérer sur les dispositifs GPU la reconstruction des images TEP à partir des données d’acquisition en mode liste. En fait, le mode liste offre de nombreux avantages par rapport à la reconstruction à partir des sinogrammes, entre autres : il permet d’implanter facilement et avec précision la correction du mouvement et le temps de vol (TOF : Time-Of Flight) pour améliorer l’exactitude de la quantification. Il permet aussi d’utiliser les fonctions de bases spatio-temporelles pour effectuer la reconstruction 4D afin d’estimer les paramètres cinétiques des métabolismes avec exactitude. Cependant, d’une part, l’utilisation de ce mode est très limitée en clinique, et d’autre part, il est surtout utilisé pour estimer la valeur normalisée de captation SUV qui est une grandeur semi-quantitative limitant le caractère fonctionnel de la TEP. Nos contributions sont les suivantes : - Le développement d’une nouvelle stratégie visant à accélérer sur les dispositifs GPU l’algorithme 3D LM-OSEM (List Mode Ordered-Subset Expectation-Maximization), y compris le calcul de la matrice de sensibilité intégrant les facteurs d’atténuation du patient et les coefficients de normalisation des détecteurs. Le temps de calcul obtenu est non seulement compatible avec une utilisation clinique des algorithmes 3D LM-OSEM, mais il permet également d’envisager des reconstructions rapides pour les applications TEP avancées telles que les études dynamiques en temps réel et des reconstructions d’images paramétriques à partir des données d’acquisitions directement. - Le développement et l’implantation sur GPU de l’approche Multigrilles/Multitrames pour accélérer l’algorithme LMEM (List-Mode Expectation-Maximization). L’objectif est de développer une nouvelle stratégie pour accélérer l’algorithme de référence LMEM qui est un algorithme convergent et puissant, mais qui a l’inconvénient de converger très lentement. Les résultats obtenus permettent d’entrevoir des reconstructions en temps quasi-réel que ce soit pour les examens utilisant un grand nombre de données d’acquisition aussi bien que pour les acquisitions dynamiques synchronisées. Par ailleurs, en clinique, la quantification est souvent faite à partir de données d’acquisition en sinogrammes généralement compressés. Mais des travaux antérieurs ont montré que cette approche pour accélérer la reconstruction diminue l’exactitude de la quantification et dégrade la résolution spatiale. Pour cette raison, nous avons parallélisé et implémenté sur GPU l’algorithme AW-LOR-OSEM (Attenuation-Weighted Line-of-Response-OSEM) ; une version de l’algorithme 3D OSEM qui effectue la reconstruction à partir de sinogrammes sans compression de données en intégrant les corrections de l’atténuation et de la normalisation dans les matrices de sensibilité. Nous avons comparé deux approches d’implantation : dans la première, la matrice système (MS) est calculée en temps réel au cours de la reconstruction, tandis que la seconde implantation utilise une MS pré- calculée avec une meilleure exactitude. Les résultats montrent que la première implantation offre une efficacité de calcul environ deux fois meilleure que celle obtenue dans la deuxième implantation. Les temps de reconstruction rapportés sont compatibles avec une utilisation clinique de ces deux stratégies.

Galactic cosmic ray modulation near the heliospheric current sheet

Galactic cosmic rays (GCRs) are modulated by the heliospheric magnetic field (HMF) both over decadal time scales (due to long-term, global HMF variations), and over time scales of a few hours (associated with solar wind structures such as coronal mass ejections or the heliospheric current sheet, HCS). Due to the close association between the HCS, the streamer belt, and the band of slow solar wind, HCS crossings are often associated with corotating interaction regions where fast solar wind catches up and compresses slow solar wind ahead of it. However, not all HCS crossings are associated with strong compressions. In this study we categorize HCS crossings in two ways: Firstly, using the change in magnetic polarity, as either away-to-toward (AT) or toward-to-away (TA) magnetic field directions relative to the Sun and, secondly, using the strength of the associated solar wind compression, determined from the observed plasma density enhancement. For each category, we use superposed epoch analyses to show differences in both solar wind parameters and GCR flux inferred from neutron monitors. For strong-compression HCS crossings, we observe a peak in neutron counts preceding the HCS crossing, followed by a large drop after the crossing, attributable to the so-called ‘snow-plough’ effect. For weak-compression HCS crossings, where magnetic field polarity effects are more readily observable, we instead observe that the neutron counts have a tendency to peak in the away magnetic field sector. By splitting the data by the dominant polarity at each solar polar region, we find that the increase in GCR flux prior to the HCS crossing is primarily from strong compressions in cycles with negative north polar fields due to GCR drift effects. Finally, we report on unexpected differences in GCR behavior between TA weak compressions during opposing polarity cycles.

O mercado de gás natural veicular em Curitiba : visão dos taxistas

O tema do presente estudo consiste na análise da demanda do mercado de taxistas de Curitiba frente à possibilidade de utilização de um combustível alternativo menos oneroso e poluente: o Gás Natural Veicular – GNV. O objetivo principal deste trabalho foi de analisar o mercado atual do GNV entre os taxistas de Curitiba, verificando a possibilidade de ampliar do uso do GNV por esta frota através de uma pesquisa de mercado. Os dados da pesquisa servirão de subsídios para campanhas de marketing orientadas à ampliação acelerada do uso desta tecnologia. Para tanto, realizou-se uma pesquisa de satisfação para levantar os fatores determinantes para a tomada de decisão dos taxistas de Curitiba de utilizarem ou não um combustível alternativo menos oneroso e poluente como o Gás Natural Veicular – GNV. O estudo visou obter a percepção dos taxistas de Curitiba. Com base nos resultados da pesquisa foi possível estabelecer subsídios para campanhas de marketing orientadas à ampliação acelerada do uso desta tecnologia. Para realização da pesquisa, utilizou-se uma pesquisa exploratória, com entrevistas individuais da cúpula das organizações que trabalham com o Gás Natural, prospectando novos projetos para o futuro e as perspectivas de evolução do mercado de GNV em Curitiba, a qual forneceu subsídios para a pesquisa quantitativa junto aos taxistas da cidade de Curitiba. Constatou-se que somente 36% do público estudado é usuário de gás natural veicular, mas entre os não usuários, 82% já pensou em instalar o kit gás. As principais razões pelas quais os taxistas pesquisados não utilizam o GNV são a perda de espaço no porta-malas e a perda de potência do veículo. Entre os taxistas que utilizam o GNV, no que tange aos atributos relacionados à rede de distribuição, a maior insatisfação refere-se à localização dos postos e a maior satisfação às eventuais filas para abastecimento. Nesses mesmos atributos o que obteve maior índice de importância foi justamente a localização dos postos. Entre os atributos relacionados ao produto, o maior índice de satisfação foi o nível de poluição ambiental e a maior insatisfação espaço para armazenamento, sendo o desempenho do veículo considerado o mais importante. Quanto aos atributos relacionados aos equipamentos, verificou-se a segurança com o maior índice de satisfação e de importância.

The effects of the minimum wage on earnings and employment in Brazil

This paper analyzes the effects of the mlmmum wage on both, eammgs and employment, using a Brazilian rotating panel data (Pesquisa Mensal do Emprego - PME) which has a similar design to the US Current Population Survey (CPS). First an intuitive description of the data is done by graphical analysis. In particular, Kemel densities are used to show that an increase in the minimum wage compresses the eamings distribution. This graphical analysis is then forrnalized by descriptive models. This is followed by a discussion on identification and endogeneity that leads to the respecification of the model. Second, models for employment are estimated, using an interesting decomposition that makes it possible to separate out the effects of an increase in the minimum wage on number of hours and on posts of jobs. The main result is that an increase in the minimum wage was found to compress the eamings distribution, with a moderately small effect on the leveI of employment, contributing to alleviate inequality.