Solid-state Marx based two-switch voltage modulator for the On-Line Isotope Mass Separator accelerator at the European Organization for Nuclear Research

A new circuit topology is proposed to replace the actual pulse transformer and thyratron based resonant modulator that supplies the 60 kV target potential for the ion acceleration of the On-Line Isotope Mass Separator accelerator, the stability of which is critical for the mass resolution downstream separator, at the European Organization for Nuclear Research. The improved modulator uses two solid-state switches working together, each one based on the Marx generator concept, operating as series and parallel switches, reducing the stress on the series stacked semiconductors, and also as auxiliary pulse generator in order to fulfill the target requirements. Preliminary results of a 10 kV prototype, using 1200 V insulated gate bipolar transistors and capacitors in the solid-state Marx circuits, ten stages each, with an electrical equivalent circuit of the target, are presented, demonstrating both the improved voltage stability and pulse flexibility potential wanted for this new modulator.

Repetitive Solid State Pulse Modulator Based on a DC Voltage Multiplier

A newly developed solid-state repetitive high-voltage (HV) pulse modulator topology created from the mature concept of the d.c. voltage multiplier (VM) is described. The proposed circuit is based in a voltage multiplier type circuit, where a number of d.c. capacitors share a common connection with different voltage rating in each one. Hence, besides the standard VM rectifier and coupling diodes, two solid-state on/off switches are used, in each stage, to switch from the typical charging VM mode to a pulse mode with the d.c. capacitors connected in series with the load. Due to the on/off semiconductor configuration, in half-bridge structures, the maximum voltage blocked by each one is the d.c. capacitor voltage in each stage. A 2 kV prototype is described and the results are compared with PSPICE simulations.

Mortality from asthma in the state of S. Paulo, Brazil (1970-1992)

Mortality from asthma has shown important variations over time in several countries. In Brazil, a mortality study performed in the 60s, covering the cities of S.Paulo and Ribeirão Preto, and other ten cities showed that S.Paulo presented the lowest death rate from asthma among of them all. It was decided to study the time trends of deaths from asthma and from the whole set of respiratory diseases from 1970 to 1992, in the population aged 15-34 yrs. old in the State of S.Paulo, as well as to compare them with those of other countries. Asthma mortality rates during the 23 years of observation since 1975, showed an oscillatory declining pattern with a peak of deaths in the initial years. The linearization of the curve allows the calculation of Pearson's correlation coefficient that was significantly negative, suggesting a decline in the mortality over this period, mainly in the 5-9 yrs. old and 30-34 yrs. old strata. The segmentation of data between the period of ICD-9, 1970 to 1978, and of ICD-9, 1979 and subsequent years, shows that there is stability within each period, in all age-groups, except for that of 5-9 yr. olds between 1970-1978. Comparing the rates of the population aged 15-34 yrs. old for the State of S. Paulo, Brazil, with trends observed in 14 other countries, an intermediate pattern for the first triennial period (1970-1972) as well as for the subsequent triennial periods, emerges. A prevalence study of asthma, a follow up program meant for using emergency rooms and a surveillance of deaths due to all respiratory diseases and specifically to asthma are strongly recommended.

Situação nutricional e alimentar de pré-escolares no semi-árido da Bahia (Brasil): I.Avaliação antropométrica

Foram estudados 754 pré-escolares de áreas urbanas de sete municípios do semi-árido da Bahia, Brasil. Os objetivos foram determinar a prevalência de déficit ponderal e estatural, indicativos de desnutrição atual e/ou pregressa e sua associação com a idade, sexo, renda em salário-mínimo (SM), escolaridade materna e adequação do consumo alimentar. Encontrou-se 22,9% de crianças com altura/idade abaixo de -2,0 DP (desnutrição pregressa), 19,1% com peso/idade e 3,6% com peso/altura abaixo de -2,0 DP (desnutrição atual). Em relação ao inquérito dietético somente 6,8% das crianças haviam consumido no dia anterior uma dieta que suprisse os requerimentos energéticos para sua faixa etária. Houve forte associação entre os indicadores A/l e P/l inadequados com renda familiar per capita (p=0,001 e p=0,000, respectivamente); crianças de famílias com renda per capita < 1/4 SM tinham duas vezes mais chance de estar desnutridas se comparadas com as do estrato de renda >1/2 SM. Em relação ao P/A como também P/l, os pré-escolares estudados no semi-árido apresentaram prevalências significativamente superiores às encontradas por pesquisa nacional realizada na mesma época (p=0,047 e p=0,000, respectivamente). Esses achados surpreendem, já que nas últimas décadas tem sido demonstrada no Brasil uma melhoria signifivativa na desnutrição e mortalidade infantil e parecem indicar que as crianças do semi-árido não lograram ainda alcançar os mesmos benefícios que o restante da população infantil brasileira.

Situação nutricional e alimentar de pré-escolares no semi-árido da Bahia (Brasil): II ­ Hipovitaminose A

Foram estudados 754 pré-escolares de áreas urbanas de sete municípios do semi-árido do Estado Bahia, Brasil, com o objetivo de determinar a prevalência da hipovitaminose A e sua associação com a idade, sexo, renda em salário-mínimo, escolaridade materna e adequação dietética em vitamina A. Na amostra estudada não se registrou nenhum caso de sinais e/ou sintomas de xeroftalmia durante o exame clínico-oftalmológico. Em 563 crianças foi possível a coleta de sangue para determinação de retinol sérico; encontrou-se um valor médio de 20,3 µg/dl (DP=10,8µg/dl) e uma prevalência de 15,3% de níveis deficientes (abaixo de 10,0 µg/dl). Em todos os sete municípios estudados a prevalência de retinol sérico deficiente foi superior a 5,0% que é nível crítico proposto pela OMS para considerar a hipovitaminose A como problema de saúde pública. A distribuição de retinol sérico encontrada não teve relação com o sexo das crianças, mas com a idade, diminuindo a prevalência de níveis deficientes e baixos na medida em que a idade aumenta. Não se encontrou associação entre renda familiar per capita ou escolaridade materna e a prevalência de níveis de retinol deficiente. Os resultados de consumo alimentar provenientes do inquérito recordatório de 24h mostraram que apenas 8% das crianças consumiram quantidades adequadas de retinol ou de seus precursores; 66% ingeriam abaixo da metade e quase 35% delas não chegaram a ingerir nem um quarto da quantidade recomendada para sua faixa etária. A carência de vitamina A deve ser considerada como problema de saúde pública severo, tanto pela alta prevalência de níveis deficientes de retinol em todos os municípios como também pela dimensão da inadequação dietética.

A energia das ondas e o seu aproveitamento

As crises energéticas surgidas no decorrer do último século, incluindo a crise do petróleo, obrigaram o Homem a procurar cada vez mais fontes de energia alternativas e preferencialmente inesgotáveis. Desta situação, resultou uma forte aposta na exploração das fontes de energias renováveis, que são uma das principais alternativas para responder a um aumento de procura, e também, face às exigências de consumos actuais, beneficiando de ao se apostar numa energia limpa e renovável existir uma forte redução nos impactes ambientais que outras fontes de energia não apresentam. O aproveitamento dos recursos provenientes de fontes de energia renováveis para a produção de energia já existe há vários anos, e, em alguns casos, atingiram já um estado de maturidade considerável, como é caso da energia eólica. Em comparação, o mesmo já não acontece com a energia das ondas. Embora o oceano apresente um recurso com enorme potencial para ser explorado, incluindo as ondas e correntes oceânicas, os dispositivos tecnológicos necessários para a exploração deste recurso encontram-se maioritariamente ainda em fase experimental, havendo casos pontuais que atingiram a fase pré-comercial. Assim, não existe até à data um dispositivo padrão para a exploração da energia das ondas em grande escala, contrariamente ao que acontece com a energia eólica. Para esta situação, contribuiu o elevado número de dispositivos patenteados para a exploração da energia das ondas, nenhum deles com vantagens significativas relativamente a outros, e também, devido ao facto de a exploração deste tipo de energia não poder ser feito de igual modo na costa ou a muitos quilómetros dela. Na presente dissertação são apresentados alguns dos principais dispositivos existentes para a extracção de energia proveniente das ondas oceânicas, com especial atenção para os dispositivos de coluna de água oscilante.

Evaluating Tsunami Impact on the Gulf of Cadiz Coast (Northeast Atlantic).

The Gulf of Cadiz coasts are exposed to tsunamis. Emergency planning tools are now taking into account this fact, especially because a series of historical occurrences were strikingly significant, having left strong evidence behind, in the mareographic records, the geological evidence or simply the memory of the populations. The study area is a strip along the Algarve coast, south Portugal, an area known to have been heavily impacted by the 1 November 1755 event. In this study we use two different tsunami scenarios generated by the rupture of two thrust faults identified in the area, corresponding to 8.1-8.3 magnitude earthquakes. Tsunami propagation and inundation computation is performed using a non-linear shallow water code with bottom friction. Numerical modeling results are presented in terms of flow depth and current velocity with maximum values of 7 m and 8 m/s for inundation depth and flow speed, respectively. These results constitute a valuable tool for local authorities, emergency and decision planners to define the priority zones where tsunami mitigation measures must be implemented and to develop tsunami-resilient communities.

Reliability of self-reported weight and height among State bank employees

INTRODUCTION: Self-reported weight and height were compared with direct measurements in order to evaluate the agreement between the two sources. METHOD: Data were obtained from a cross-sectional study on health status from a probabilistic sample of 1,183 employees of a bank, in Rio de Janeiro State, Brazil. Direct measurements were made of 322 employees. Differences between the two sources were evaluated using mean differences, limits of agreement and intraclass correlation coefficient (ICC). RESULTS AND CONCLUSIONS: Men and women tended to underestimate their weight while differences between self-reported and measured height were insignificant. Body mass index (BMI) mean differences were smaller than those observed for weight. ICC was over 0.98 for weight and 0.95 for BMI, expressing close agreement. Combining a graphical method with ICC may be useful in pilot studies to detect populational groups capable of providing reliable information on weight and height, thus minimizing resources needed for field work.

Cancer incidence in eighteen cities of the State of São Paulo, Brazil

OBJECTIVE: As in Brazil cancer registries are mostly based on large cities, there are no estimates per state or per region and information on the disease incidence in the vast in-land areas is very scarce. An incidence survey was conducted in 18 major cities of the state of São Paulo, excluding the capital, aiming to collect information about cancer incidence in the state of São Paulo. METHODS: Of the 18 cities in state of São Paulo included in the survey, all had available resources for cancer management. Data from the year of 1991 were collected by the personnel of the Instituto Brasileiro de Geografia e Estatística (Brazilian Institute of Statistics), who were especially trained by the study coordinators at the Fundação Oncocentro de São Paulo (Cancer Center of São Paulo). The collected data were processed and analyzed at the Oncocentro. Data collection, processing, and analyses were performed according to the recommendations of the International Agency for Research on Cancer. RESULTS: Although some discrepancies were observed in cancer incidence rates between the cities, results obtained for all 18 cities combined were remarkably close to those recently found for the city of São Paulo in the year 1993. One remarkable finding was the relatively high cancer incidence rates in both sexes in the city of Santos. CONCLUSIONS: The very similar all-sites cancer incidence rates found in the year 1991, when compared to those for the city of São Paulo in the year 1993, are suggestive that all regions have common cancer-related factors. Nevertheless, other explanations, such as the inclusion in the study of prevalent cases, as well as of non-residents, may have occurred in both studies, biasing the results. There is a need of further studies to confirm the high cancer incidence in Santos.

Intra-population plasticity of Anopheles darlingi's (Diptera, Culicidae) biting activity patterns in the state of Amapá, Brazil

OBJECTIVE: To assess the variation in Anopheles darlingi's biting activity compared to An. marajoara in the same locality and to biting activity data from other regions. METHODS: Using human bait, eight observations of the biting activity of An. darlingi and An. marajoara were carried out during 1999 and 2000 in the municipality of São Raimundo do Pirativa, state of Amapá, Brazil. Each observation consisted of three consecutive 13-hour collections, close to full moon. There were shifts of collectors in the observation points and nocturnal periods. RESULTS: An. darlingi revealed considerable plasticity of biting activity in contrast to An. marajoara, which showed well-defined crepuscular biting peaks. No significant correlation between density and biting activity was found, but a significant correlation existed between time and proportional crepuscular activity, indicating underlying ecological processes not yet understood. Two of the four available data sets having multiple observations at one locality showed considerable plasticity of this species' biting patterns as well. CONCLUSION: Intra-population variation of biting activity can be as significant as inter-population variation. Some implications in malaria vector control and specific studies are also discussed.

Solid-State Bipolar Marx Generator with Voltage Droop Compensation

This paper addresses the voltage droop compensation associated with long pulses generated by solid-stated based high-voltage Marx topologies. In particular a novel design scheme for voltage droop compensation in solid-state based bipolar Marx generators, using low-cost circuitry design and control, is described. The compensation consists of adding one auxiliary PWM stage to the existing Marx stages, without changing the modularity and topology of the circuit, which controls the output voltage and a LC filter that smoothes the voltage droop in both the positive and negative output pulses. Simulation results are presented for 5 stages Marx circuit using 1 kV per stage, with 1 kHz repetition rate and 10% duty cycle.

Solid-State Bipolar Marx Converter with Output Transformer and Energy Recovery

The purpose of this paper is to present and discuss a general HV topology of the solid-state Marx modulator, for unipolar or bipolar generation connected with a step-up transformer to increase the output voltage applied to a resistive load. Due to the use of an output transformer, discussion about the reset of the transformer is made to guarantee zero average voltage applied to the primary. It is also discussed the transformer magnetizing energy recovering back to the energy storage capacitors. Simulation results for a circuit that generates 100 kV pulses using 1000 V semiconductors are presented and discussed regarding the voltage and current stress on the semiconductors and result obtained.

Portuguese-Americans in the East Coast: is “crystallization” a myth?

In the last but one census of the population in the US, I had to respond as a foreigner resident, and when I was asked about my race, I chose to answer the ways I had heard the activists of the civil rights movement used to do in the US, when color blindness was an important thing to fight for – to “RACE” I added “HUMAN”...

Boulder deposition during major tsunami events

A remarkable accumulation of marine boulders located above the present spring tide level has occurred in two coastal lowlands of the Algarve (Portugal). The size-interval of the particles studied here is seldom reported in the literature in association with extreme events of coastal inundation, thus making this study of relevance to many other coasts worldwide. The spreads of boulders extend several hundred meters inland and well beyond the present landward limit of storm activity. The marine origin of the boulders is demonstrated by well-developed macro-bioerosion sculpturing and in situ skeletal remains of endolithic shallow marine bivalves. The good state preservation of the fossils within the boulders indicates that abrasion duringtransport and redeposition was not significant. We envisage boulder deposition as having taken place during the Lisbon tsunami of ad 1755 through the simultaneous landward entrainment of coarse particles from nearshore followed by rapid shoreward suspended-dominated transport and non-graded redeposition that excluded significant sorting by weight or boulder dimensions. We use numerical hydrodynamic modeling of tsunami (and storm) waves to test the observational data on boulder dimensions (density, size, distribution) on the most likely processes of sediment deposition. This work demonstrates the effectiveness of the study of boulder deposits in tsunami reconstruction. Copyright (C) 2011 John Wiley & Sons, Ltd.

Occupational accidents among middle and high school students of the state of São Paulo, Brazil

OBJECTIVES: To estimate the prevalence of occupational injuries and identify their risk factors among students in two municipalities. METHODS: A cross-sectional survey was conducted in public schools of the municipalities of Santo Antonio do Pinhal and Monteiro Lobato, Brazil. A stratified probabilistic sample was drawn from public middle and high schools of the study municipalities. A total of 781 students aged 11 to 19 years participated in the study. Students attending middle and high school answered a comprehensive questionnaire on living and working conditions, as well as aspects of work injuries, and health conditions. Multiple logistic regression models were fitted to estimate risk factors of previous and present occupational injuries. RESULTS: Of 781 students, 604 previously had or currently have jobs and 47% reported previous injuries. Among current workers (n=555), 38% reported injuries on their current job. Risk factors for work injuries with statistically significant odds ratio >2.0 included attending evening school, working as a housekeeper, waiter or brickmaker, and with potentially dangerous machines. CONCLUSIONS: The study results reinforce the need of restricting adolescent work and support communities to implement social promotion programs.