Resumo Drogas anti-helmínticas têm sido usadas estrategicamente em rebanhos criados nos trópicos. Essas drogas têm sido utilizadas no tratamento do endoparasitismo, o que resultou em um aumento no desempenho dos animais. A cutia (Dasyprocta leporina) é um roedor neotropical com potencial para domesticação e tem sido criada intensivamente em Trinidad. Porém, o objetivo desta pesquisa foi investigar o efeito do uso de anti-helmínticos no desempenho de crescimento da cutia. Através de uma busca na literatura, constatou-se que esse tipo de estudo na cutia não foi realizado. Neste experimento, quatorze cutias desmamadas pesando 1kg foram divididas em dois grupos aleatoriamente. O primeiro grupo (T1) não recebeu nenhum tratamento anti-helmíntico, mas o segundo grupo (T2) foi tratado com Endovet Ces® por via subcutânea a cada três meses. Não houve diferenças significativas (p> 0,05) entre os dois grupos no peso da carcaça, ganho de peso, porcentagem de cobertura (quente e frio), coração, pulmão, pele, cabeça e pés. No entanto, uma diferença significativa (p <0,05) foi observada entre os grupos no peso do fígado e depenagem. Para os autores, esta é a primeira vez que parâmetros de carcaça são apresentados na literatura. O peso vivo dos animais ao final do experimento variou de 2,4 kg a 2,6 kg e os animais tinham uma porcentagem de curativo de 57% a 55%. Os resultados sugerem que o uso de anti-helmínticos em cutias criadas intensivamente não teve efeito significativo no ganho de peso e na porcentagem de curativo.

Abstract Anthelmintic drugs have been used strategically in livestock reared in the tropics. These drugs have been used in the treatment of endoparasitism which have resulted in an increase in the animals’ performance. The agouti (Dasyprocta leporina) is a neo-tropical rodent with the potential for domestication and has been farmed intensively in Trinidad. However, the objective of this research was to investigate the effect of anthelmintic use of the growth performance of the agouti. In searching the literature, it was found that this type of study on the agouti has not been done. In this experiment fourteen weaned agoutis weighing 1kg were divided into two groups randomly. The first group (T1) was not given any anthelmintic treatment but the second group (T2) was treated with Endovet Ces® subcutaneously every three months. There were no significant differences (p > 0.05) between the two groups in the carcass weight, weight gain, dressing percentage (hot and cold), heart, lungs, skin, head and feet. However, a significant difference (p < 0.05) was seen between groups in the weight of liver and pluck. To the authors knowledge this is the first time that carcass parameters has been presented in literature. The live weight of the animals at the end of the experiment ranged from 2.4 kg to 2.6 kg and animals had a dressing percentage of 57% to 55%. The results are suggestive that the use of anthelmintic drugs in agoutis reared intensively had no significant effect on weight gain and dressing percentage.

Resumo Parasitas de importância veterinária têm se concentrado fortemente em animais domésticos que foram introduzidos na região neotrópica. O texto usado no ensino de parasitologia para estudantes de veterinária em Trinidad investigou apenas os parasitas de espécies domesticadas. No texto de parasitologia veterinária revisado, nenhuma menção foi feita sobre os parasitas que afetam os animais selvagens neotropicais. As informações sobre animais selvagens neotropicais tiveram que ser obtidas a partir de textos sobre o manejo de animais selvagens nos Neotrópicos. Os textos revisados neste documento vão de meados da década de 1950 até 2020. As informações apresentadas nesta revisão revelam o trabalho exaustivo realizado sobre os parasitas de espécies domesticadas, mas também revelaram poucas informações sobre animais neotropicais com potencial para domesticação. Em conclusão, esta revisão revela a lacuna de informação que existe nos textos de parasitologia utilizados no ensino de estudantes de veterinária. No futuro, esses textos de parasitologia podem ser revisados para incluir capítulos sobre os parasitas de animais neotropicais com potencial para domesticação. Atualmente, os alunos que se formam no curso de parasitologia veterinária têm poucas informações sobre os parasitas de animais que estão presentes em seus “quintais”.

Abstract Parasites of veterinary importance have been heavily focused on domesticated livestock that was introduced into the neo-tropics. The text used in the teaching parasitology to veterinary students in Trinidad has only investigated the parasites of domesticated species. In the reviewed veterinary parasitology text no mention was made on the parasites that affect wild neo-tropical animals. Information on wild neo-tropical animals had to be sourced from texts on the management of wild life animals in the Neotropics. The texts that were reviewed in this document spanned from the mid-1950s to 2020. The information presented in this review reveals the exhaustive work done on the parasites of domesticated species but also revealed little information on neo-tropical animals with the potential for domestication. In conclusion, this review reveals the gap of information that is missing from parasitology texts used in the teaching of veterinary students. In the future these parasitology texts can be revised to include chapters on the parasites of neo-tropical animals with the potential for domestication. At present students that graduate from the veterinary parasitology course has little information on the parasites of animals which are present in their ‘backyards’.

Resumo As doenças reprodutivas têm sido bem documentadas em rebanhos domésticos, como ovinos, caprinos, bovinos e suínos. Porém, há muito pouca informação sobre essas doenças na cutia (Dasyprocta leporina). A cutia é usada como carne na América do Sul e no Caribe. Mais recentemente, a criação intensiva desse animal está sendo praticada na região neotropical., Há escassez de informações sobre distocia e prolapsos vaginais na cutia. Este documento relata três casos de doenças reprodutivas em cutias criadas em cativeiro em Trinidad e Tobago. O primeiro caso foi de uma cutia de aproximadamente 3 kg que estava na última fase de gestação, encontrada morta em sua gaiola. A vulva da mãe tinha as patas traseiras salientes do feto. A avaliação necroscópica da carcaça revelou pouco tecido adiposo e a mãe tinha dois fetos no corno direito do útero. Cada feto pesava aproximadamente 200 g. Os fetos eram bem formados com pelos, dentes e olhos. A placenta foi presa a cada feto. Os achados patológicos sugeriram que a distocia resultou de inércia uterina secundária, que foi a causa da morte da cutia adulta. O segundo caso foi o de uma cutia adulta pesando 2,5 kg. Essa fêmea deu à luz uma cria três semanas antes e foi observado que tinha prolapso vaginal., A cirurgia foi realizada e a vagina prolapsada foi colocada de volta na cavidade pélvica. Após essa intervenção, a vagina prolapsou duas vezes. Após a reinserção do tecido vaginal, a cutia foi eutanasiada. O terceiro caso também foi de distocia. No entanto, os fetos pesavam 235 g e 165 g e estavam em apresentação, postura e posicionamento normais. O feto, entretanto, não conseguiu passar pela vagina e ficou preso na cavidade pélvica. Isso causou inércia uterina secundária, que foi a causa da morte. As causas das doenças reprodutivas nesses casos são desconhecidas, mas o manejo da alimentação e o espaço concedido à cutia no final da gestação podem ser fatores contribuintes.

Abstract Reproductive diseases have been well documented in domestic livestock such as sheep, goat, cattle and pigs. However, there is very little information on these diseases in the agouti (Dasyprocta leporina). The agouti is used for its meat in South America and the Caribbean. More recently, intensive farming of this animal is being practiced in the Neotropics. There is dearth of information on dystocia and vaginal prolapses in the agouti. This document reports on three cases of reproductive diseases in captive reared agoutis in Trinidad and Tobago. The first case was a female agouti weighing approximately 3 kg that was in the last stage of pregnancy, which was found dead in its cage. The vulva of the mother had the protruding hind-limbs of the fetus. Necroscopic evaluation of carcass revealed little fat tissue and the mother had two fetuses in the right horn of the uterus. Each fetus weighed approximately 200 g. The fetuses were well formed with fur, teeth and eyes. The placenta was attached to each fetus. The pathological findings suggested that dystocia resulted from secondary uterine inertia which was the cause of death of the adult female agouti. The second case was that of an adult female agouti weighing 2.5 kg. This female had given birth to an offspring three weeks prior and was observed to have had a vaginal prolapse. Surgery was performed and the prolapsed vagina was placed back into the pelvic cavity. Further to this intervention, the vagina prolapsed twice. Subsequent to the re-insertion of the vaginal tissue the agouti was euthanized. The third case was also that of a dystocia. However, the fetuses weighed 235 g and 165 g respectively and were in normal presentation, posture and positioning. The fetus however was unable to pass via the vagina and was trapped in the pelvic cavity. This caused secondary uterine inertia which was the cause of death. The causes of reproductive diseases in these cases are unknown but the feeding management and space allowance given to the agouti in late gestation may be contributing factors.

Resumo O desenvolvimento de um sistema de criação em cativeiro para as espécies de gambá do Caribe amplamente caçadas, Didelphis marsupialis insularis, pode auxiliar bastante no manejo e conservação dessa espécie nos neotrópicos. Embora essa espécie possua características ideais para a criação em cativeiro nessa região (tolerância a altas temperaturas e umidade, alta taxa de reprodução e resistência a doenças), alguns fatores, como o seu comportamento agressivo e informações limitadas sobre seu comportamento reprodutivo, impediram o desenvolvimento de um sistema para D. m. insularis. O presente estudo descreve um sistema de criação e o comportamento reprodutivo dessa espécie em condições de cativeiro. Seis gambás adultos (1 macho e 5 fêmeas) foram mantidos para reprodução durante um período de 10 meses. O tamanho da ninhada em bolsa foi em média de 5 ± 2,5 com um intervalo de 2 a 8. A duração da gestação foi de 13,25 ± 0,96 dias, e 4 ninhadas (n = 23) foram desmamadas com sucesso de 11 a 13 semanas. Verificou-se que o macho D. m. insularis exibe comportamentos de interesse que podem servir como indicadores de receptividade da fêmea, e, em geral, essa espécie pode ser criada com sucesso em condições de cativeiro nos neotrópicos.

Abstract Developing a captive breeding system for the widely hunted Caribbean species of opossum Didelphis marsupialis insularis can greatly aide in the management and conservation of this species in the neo-tropics. Although this species possesses ideal traits for captive breeding in this region (tolerance to high heat and humidity, high reproductive rate, and resistance to disease), challenges due to its aggressive behaviour and limited information on its breeding behaviour have prevented a system from being developed for this species. The present study describes a breeding system, and the reproductive behaviour of this species under captive conditions. Six (1 male; 5 females) adult opossums were maintained and managed for breeding over a ten (10) month period. Pouch litter sizes averaged 5±2.5 with a range of 2 to 8. Gestation length was found to be 13.25±0.96 days and 4 litters (n=23) were successfully weaned at 11-13 weeks. It was found that the male D. m. insularis exhibits behaviours of interest that can serve as indicators for receptivity of the female, and overall, that this species can be successfully reared and bred under captive conditions in the neo-tropics.

Resumo As instalações de reabilitação e assistência à vida selvagem na região neotropical do Caribe são limitadas, mas informações relevantes sobre populações selvagens podem ser obtidas nesses locais. Didelphis marsupialis insularis é uma espécie de marsupial neotropical, subestimada e popularmente caçada; no entanto, essa espécie está sendo cada vez mais admitida para a reabilitação. Os objetivos deste estudo foram: 1. Registrar as experiências de reabilitação de D. marsupialis insularis na ilha neotropical de Trinidad e Tobago; e 2. Extrair e destacar informações sobre a biologia dessa subespécie de gambá. Utilizando registros de admissão, obtidos ao longo de um período de aproximadamente quatro anos, foram mostrados dois períodos de reprodução, de fevereiro a março e de agosto a outubro. O tamanho da ninhada foi em média de cinco indivíduos, variando de um a oito jovens. Comumente encontrado em áreas urbanas do país, os ataques de cães foram relatados como a principal causa de internação dessa espécie. Assim, a informação registrada por essa instalação de reabilitação de vida selvagem forneceu uma grande visão sobre o gambá D. marsupialis insularis, que tem sido pouco estudado.

Abstract Wildlife rehabilitation facilities in the Caribbean region are limited, yet they can provide relevant information on wild populations. Didelphis marsupialis insularis is a popularly hunted, under-studied, neo-tropical marsupial species that is increasingly being admitted for rehabilitation. The aim of this study was 1. To record the experiences of rehabilitating D. marsupialis insularis in the neo-tropical island of Trinidad and Tobago and 2. To extract and highlight information on the biology of this opossum sub-species. Using admission records, obtained over a roughly four year period, two breeding periods (February to March and August to October) were illustrated. Litter sizes averaged five individuals, with a range of 1 to 8 young. This species was found to be common in urban areas of the country, with dog attacks reported as the major cause for admission. Thus the information recorded by this wildlife rehabilitation facility has provided great insight on the sparsely studied opossum, D. marsupialis insularis.

The global burden of chronic kidney disease (CKD) is rapidly increasing with a projection of becoming the 5th most common cause of years of life lost globally by 2040. CKD is a major cause of catastrophic health expenditure. The costs of dialysis and transplantation consume up to 3% of the annual healthcare budget in high-income countries. However, the onset and progression of CKD is often preventable. In 2020, the World Kidney Day campaign highlights the importance of preventive interventions – be it primary, secondary, or tertiary. This article focuses on outlining and analyzing measures that can be implemented in every country to promote and advance CKD prevention. Primary prevention of kidney disease should focus on the modification of risk factors and addressing structural abnormalities of the kidney and urinary tracts, as well as exposure to environmental risk factors and nephrotoxins. In persons with pre-existing kidney disease, secondary prevention, including blood pressure optimization and glycemic control, should be the main goal of education and clinical interventions. In patients with advanced CKD, management of co-morbidities such as uremia and cardiovascular disease is a highly recommended preventative intervention to avoid or delay dialysis or kidney transplantation. Political efforts are needed to proliferate the preventive approach. While national policies and strategies for non-communicable diseases might be present in a country, specific policies directed toward education and awareness about CKD screening, management, and treatment are often lacking. Hence, there is an urgent need to increase the awareness of preventive measures throughout populations, professionals, and policy makers.

ABSTRACT Brazilian processing plants have identified the so-calledspaghetti breast myopathy characterized by muscular dystrophy of unknown etiology. This study aimed at estimating the incidence of spaghetti breast myopathyin broilers from three commercial genetic strains (Ross, Cobb, Hubbard) reared in two different housing systems (DH, Dark house, and TS, Tunnel system), presenting different controlled ventilation systems and light availability. Breast meat samples (n=5,580) were collected and macroscopically evaluated for spaghetti breast myopathy according to a 0-2 scale, as 0 = normal, 1 = intermediate or moderate, and 2 = severe. A higher number of broilers reared in DH presented normal breasts and moderate myopathy relative to TS-reared birds. Ross broilers presented a higher incidence of normal breasts compared with Cobb and Hubbard broilers. The risk of presenting spaghetti breast myopathy was higher in broilers reared in DH than those in reared in TS, indicating that the exposure to DH environmental conditions may increase the chance of myopathy incidence. Broilers reared in dark houses presented 26% higher chance and 13% higher risk of showing spaghetti-breast myopathy the than those reared in tunnel-ventilated systems.

Resumo A cutia (Dasyprocta leporina) produz filhotes precoces, e é a espécie cinegética mais caçada e criada em muitos países neotropicais. O entendimento da biologia reprodutiva, incluindo a relação entre o tamanho da ninhada e a funcionalidade das glândulas mamárias é crucial para o manejo conservacionista deste animal. Nos mamíferos precoces, como a cutia, manter o contato materno para a aprendizagem de padrões de forrageamento pode ser mais importante do que a demanda energética e de restrição nutricional durante a lactação, e a amamentação pode não desempenhar um papel importante quando comparado aos mamíferos altriciais. Portanto, neste estudo nós avaliamos a relação entre a funcionalidade mamária com o tamanho da ninhada, peso ao nascer da ninhada, e o número de partos em cutias cativas. A funcionalidade foi avaliada por meio de palpação manual das glândulas mamárias em fêmeas não sedadas (N=43). Nós comparamos a média do peso ao nascer de todos os recém-nascidos, macho e fêmeas recém-nascidos entre cutias com diferentes tamanhos de ninhadas e diferentes parturições, por meio da análise one–way ANOVA unifatorial; enquanto o teste do chi-quadrado de Pearson foi utilizado para detectar as relações entre a funcionalidade da glândula mamária, o tamanho da ninhada e o número de partos. O número de partos teve efeito na média de peso ao nascer dos filhotes (F0,822, P > 0,05), filhotes machos (F0,80, P > 0,05) ou filhotes fêmeas (F0,66, P > 0,05) nas ninhadas. A análise bivariada de Pearson (i) não mostrou correlação (P > 0,05) entre a funcionalidade da glândula mamária e o tamanho da ninhada e (ii) nenhuma correlação significativa (P > 0,05) entre a funcionalidade da glândula mamária e o número de parições. Os resultados sugerem que, embora todos os pares de tetas fossem funcionais, as cutias recém-nascidas podem não depender da nutrição materna para sobreviver; .embora todos os pares de tetas sejam funcionais, as cutias recém nascidas aparentemente não dependem da nutrição materna para sua sobrevivência; esta é, provavelmente, uma estratégia evolutiva que resulta em grandes populações da cutia em vida livre; e que pode explicar sua popularidade como espécie cinegética

Abstract The red-rumped agouti (Dasyprocta leporina) produces precocial young and is the most hunted and farmed game species in several Neotropical countries. An understanding of the reproductive biology, including the relationship between litter size and teat functionality is crucial for conservation management of this animal. In precocial mammals, as the red-rumped agouti, maintaining maternal contact to learn foraging patterns may be more important than the energy demands and nutritional constraints during lactation and suckling may not play important roles when compared to altricial mammals. Therefore, in this study we evaluated the relationship between mammary functionality with litter size, litter birth weight, and parturition number in captive red-rumped agouti. Functionality was assessed by manual palpation of teats from un-sedated females (N=43). We compared the average birth weight of all newborns, male newborns and female newborns among agoutis with different litter sizes and different parturitions by one way ANOVA’s, while Pearson’s Chi-squared tests were used to detect relationships between teat functionality, litter size, and parturition number. Parturition number had no effect on the mean birth weight of all young (F0.822, P > 0.05), male young (F0.80, P > 0.05) or female young (F0.66, P > 0.05) in the litters. We found (i) no significant correlations (P > 0.05) between teat functionality and litter size and (ii) no significant correlations (P > 0.05) between teat functionality and parturition number. This suggests that whilst all teat pairs were functional, functionality was a poor indicator of litter size; suggesting that female agouti young may not have a high dependency on maternal nutrition; an possible evolutionary strategy resulting in large wild populations; hence its popularity as a game species.

ABSTRACT There is limited data on community-acquired acute kidney injury (CA-AKI) in low/middle-income countries. This retrospective study focussed on the prevalence, severity and outcomes of CA-AKI at an institution in Jamaica. The selected population was patients who attended the University Hospital of the West Indies between January 2015 and June 2015. Acquired kidney injury was diagnosed and staged by KDIGO criteria. Four hundred and thirty-two patients (4.22%) met the diagnostic criteria of acute kidney injury (AKI). Of these, 171 (39.6%) had stage I AKI, 110 (25.5%) had stage II and 151 (35.0%) had stage III. Certain underlying causes such as volume depletion, various infections and cardiac failure were most prevalent causes of CA-AKI. Among the underlying causes, volume depletion remained as the leading cause of CA-AKI. Patients who had underlying causes which required urgent medical attention are likely to achieve recognition of CA-AKI at an early stage (95% CI: 1.884, 2.128, p < 0.001). Volume depletion and cardiac failure significantly increased the risk of CA-AKI (OR. 2.037, 95% CI: 1.130, 1.651, p = 0.004 and OR, 1.759, 95% CI: 1.827, 1.982, p = 0.03), respectively. Ninety-four patients (21.8%) had incomplete and 46 patients (10.6%) had no renal recovery at ≥ 90 days. The majority of patients who achieved complete renal recovery were patients who had stage I AKI (90.1%). Fifty-two patients with CAAKI (12%) required dialysis and most of them (86.5%) had stage III AKI. Stages I and II CA-AKI had better renal outcomes than stage III CA-AKI (95% CI: 1.566, 1.875, p < 0.001). The 30-day mortality and 90-day mortality among the patients with CA-AKI were 6.3% and 7.4%, respectively. The severity of CA-AKI varies with underlying cause. Earlier medical attention may link with better renal recovery. Volume depletion and cardiac failure are significant risk factors for CA-AKI and volume depletion remains as the leading cause of CA-AKI. Adverse outcomes are more likely to occur in patients with Stage III CA-AKI.

RESUMEN Los datos acerca de la lesión renal aguda adquirida en la comunidad (LRA-AC) en países de ingresos bajos y medios, son limitados. Este estudio retrospectivo se centró en la prevalencia, gravedad y resultados de LRA-AC en una institución en Jamaica. La población seleccionada estuvo formada por pacientes que acudieron al Hospital Universitario de West Indies entre enero de 2015 y junio de 2015. La lesión renal adquirida fue diagnosticada y dividida en etapas de acuerdo con los criterios de la organización KDIGO (siglas en inglés de “Enfermedad Renal: Mejorando los Resultados Globales”). Cuatrocientos treinta y dos pacientes (4.22%) cumplieron los criterios de diagnóstico de LRA. De estos, 171 (39.6%) estaban en la etapa I de LRA, 110 (25.5%) en la etapa II, y 151 (35.0%) en la etapa III. Ciertas causas subyacentes tales como la depleción del volumen, varias infecciones, y la insuficiencia cardíaca fueron las causas más prevalentes de LRA-AC. Entre las causas subyacentes, la depleción del volumen permaneció como la principal causa de LRA-AC. Los pacientes con causas subyacentes que requerían atención médica urgente tenían mayor probabilidad de reconocimiento de LRA-AC en una etapa temprana (IC de 95%: 1.884, 2.128, p < 0.001). La depleción del volumen y la insuficiencia cardíaca aumentaron significativamente el riesgo de LRA-AC (OR. 2.037, IC de 95%: 1.130, 1.651, p = 0.004 y OR. 1.759, IC de 95%: 1.827, 1.982, p = 0.03), respectivamente. Noventa y cuatro pacientes (21.8%) tuvieron una recuperación renal incompleta y 46 pacientes (10.6%) no tuvieron recuperación ninguna a los ≥ 90 días. La mayoría de los pacientes que lograron una recuperación renal completa eran pacientes en la etapa I de LRA (90.1%). Cincuenta y dos pacientes con LRA-AC (12%) requirieron diálisis y la mayor parte de ellos (86.5%) se encontraban en la etapa III de LRA. Las etapas I y II de LRA-AC tuvieron mejores re-sultados renales que la etapa III de LRA-AC (IC de 95%: 1.566, 1.875, p < 0.001). La mortalidad a los 30 días y a los 90 días entre los pacientes con LRA-AC fue de 6.3% y 7.4%, respectivamente. La gravedad de la LRA-AC varía según la causa subyacente. La atención médica temprana puede asociarse con una mejor recuperación renal. La depleción del volumen y la insuficiencia cardíaca son factores de riesgo significativos en la LRA-AC, y la depleción del volumen sigue siendo la causa principal de LRA-AC. Los resultados adversos son más probables en pacientes de la etapa III de LRA-AC.

The increased burden of chronic kidney disease (CKD) in disadvantaged populations is due to both global factors and population-specific issues. Low socioeconomic status and poor access to care contribute to health care disparities and exacerbate the negative effects of genetic or biological predisposition. Provision of appropriate renal care to these populations requires a two-pronged approach: expanding the reach of dialysis through development of low-cost alternatives that can be practiced in remote locations, and implementation and evaluation of cost-effective prevention strategies. Kidney transplantation should be promoted by expansion of deceased donor transplant programs and use of inexpensive, generic immunosuppressive drugs. The message of World Kidney Day 2015 is that a concerted attack against the diseases that lead to end-stage renal disease, by increasing community outreach, better education, improved economic opportunity, and access to preventive medicine for those at highest risk, could end the unacceptable relationship between CKD and disadvantage in these communities.

The ADRC tuning is essentially a pole-placement technique and the desired performance is indirectly achieved through the location of the closed-loop poles. However, the final choice of these poles becomes a trial-and-error strategy. In contrast with pole-placement, in the LQR method, the desired performance objectives are directly and globally addressed by minimizing a quadratic function of the state and control input. ADRC tuning employing the LQR approach is then applied for decoupling uncertain MIMO systems. This is done by considering all the coupling and interference interactions between the channels of the system as disturbances, using an ESO to estimate them in real time and then canceling its effect employing the estimate as part of the control signal.

O objetivo deste trabalho é apresentar uma máquina para entalhamento de corpos de prova cerâmicos, bem como a escolha e a execução do entalhamento, usando SiC sinterizado via fase líquida, com adições de Al2O3 e Yb2O3, como material experimental para ser entalhado. Foi desenvolvido e construído, junto a uma empresa de S. Carlos-SP, um equipamento que permite produzir entalhes finos em corpos cerâmicos para posterior ruptura, visando determinar K IC pelo método SEVNB. Amostras de SiC com 10% de Al2O3+Yb2O3 foram sinterizadas a 1950 ºC, retificadas e entalhadas com lâminas de barbear e pastas diamantadas de 15, 9, 6, 3, 1 e 0,25 µm. A máquina produzida para o entalhamento das amostras está em operação no DEMAR-EEL-USP e, ao que se sabe, é a primeira no Brasil. Os resultados mostraram que em função da espessura da lâmina e da granulometria do agente abrasivo, pode-se produzir entalhes com diferentes raios de curvatura de sua ponta e profundidades.

The aim of this work is to present a machine to produce notches in ceramic bodies as well the choice and how to make the notches. SiC-ceramics was produced by liquid phase sintering as testing material. For the liquid sintering, a mixture of Al2O3 and Yb2O3 as additives was applied. The machine was developed and built by a company sited in S. Carlos-SP. It permits to obtain narrow notches in ceramic specimens to be fractured afterwards. That is to facilitate the measurement of KICbased on the SEVNB method. Specimens of 10% of (Al2O3+Yb2O3) containing SiC were sintered at 1950 ºC. Those specimens were machined and notched using the machine and razor blades and diamond pastes of 15, 9, 6, 3, 1 and 0.25 µm of particle size. The built machine is installed at DEMAR-EEL-USP, and it is said to be the first of that type in Brazil. The results showed that depending on the thickness of the razor blade and the size of the diamond particles, it can be produced notches with distinct tip radius and notch depth values.

An analysis of a dual active bridge (DAB) converter under soft-switching mode in the whole operating range is presented in this paper. A detailed study of the impact of the transformer magnetizing inductance, L M, and snubber capacitance, Cxx, parameters on the soft-switching regions is carried out to obtain some design considerations. Simulation and experimental results which validate the theoretical analysis are also presented

La dilatación precoz en esofagitis caústica no está bien establecida. Objetivo: Evaluar el beneficio de la dilatación precoz, en la evolución y complicaciones de esofagitis caústicas grado II y III. Pacientes y Métodos: Estudio prospectivo de 32 niños, grupo A (dilatación precoz) y B (dilatación tardía). Se utilizo el índice de dilatación periódica para evaluar beneficio de la dilatación precoz. Resultados: edad promedio 2,3 años; 13 (40,62%) hembras y 19 (59,38%) varones; 21/32 (65,62%) desarrollaron estenosis esofágica, 6/15 (40,00%) grupo A, 15/17 (88,23%) grupo B (p=0,0041). Estenosis simples en 12/21 (57,14%), complejas 9/21 (42,85%), recurrentes 2/6 y refractaria 2/6, grupo A; 6/15 recurrente y 5/15 refractarias, 1/15 perforación esofágica, grupo B. El promedio de sesiones de dilatación 17 vs 44,6 (p=0,0297) e índice de dilatación periódica de 3,04 vs 4,11 (p=0.0002) grupo A y B respectivamente. Conclusiones: la dilatación precoz en esofagitis caústica es segura y contribuye a disminuir el número de sesiones de dilatación y complicaciones. Se destaca, la importancia de la prevención de la ingesta accidental de cáusticos.

Early dilatation in caustic esophagitis is not well established. Objective: Evaluate the benefits of early dilatation in the evolution and complications of grade I and II caustic esophagitis in children. Patients and Methods: Prospective study of 32 children, group A (early dilatation) and B (late dilatation). The periodic dilatation index was used to evaluate the benefits of early dilatation. Results: Average age 2,3 years old; 13 (40,62%) female and 19 (59,38%) male; 21/32 (65,62%) developed esophageal stenosis. 6/15 (40,00%) group A, 15/17 (88,23%) group B (p=0,0041). Simple stenosis in 12/21 (57,14%), complex 9/21 (42,85%), recurrent 2/6 and refractory 2/6, group A; 6/15 recurrent and 5/15 refractory, 1/15 esophageal perforation, group B. The average of dilatation sessions was 17 vs. 44,6 (p=0,0297) and periodic dilatation index was 3,04 vs. 4,11 (p=0.0002) group A and B respectively. Conclusions: early dilatation in caustic esophagitis is safe and contributes to decrease the number of dilatation sessions and complications

O concreto de cimento Portland é um dos materiais mais usados no mundo inteiro, entretanto, devido a sua estrutura ser muito complexa, torna-se imprescindível estudar suas propriedades com bastante profundidade. O concreto é produzido a partir de uma argamassa, de areia e cimento, com adição de agregados graúdos, sendo que suas propriedades estão basicamente suportadas nessa argamassa de constituição. O objetivo deste trabalho foi estudar a variação da rigidez de duas argamassas de composições com razão cimento:areia de 1:2 e 1:3 em função do tempo de cura, tendo como parâmetro a variação do módulo de Young. Os resultados mostraram que o módulo de Young cresce até atingir o valor máximo no oitavo dia, sendo que nos três primeiros dias esse crescimento é mais acentuado. A análise dos resultados indica que grande parte do processo de hidratação do cimento, com formação das ligações químicas responsáveis pela rigidez da argamassa, acontece nos primeiros dias de cura.

Concrete produced with Portland cement is one of building materials most widely used worldwide. However, due to its highly complex structure, its properties require in-depth studies. Concrete is a mortar consisting of a mixture of cement, sand and coarse aggregates, and its properties are represented basically by the mortar base. The aim of this work was to study the change in stiffness of two mortar compositions cured at 25 ºC with a cement-to-sand ratio of 1:2 and 1:3, as a function of curing time using the variation of Young modulus as the measuring parameter. The results showed that Young modulus increases up to a maximum value on the 8th day, and that this increase is more pronounced during the first three days. An analysis of the results indicates that a large part of the cement hydration process, involving the formation of chemical bonds that are responsible for the mortar stiffness, takes place in the early days of curing.