Migration and urban schistosomiasis. The case of São Lourenço da Mata, Northeast of Brazil

A population-based case-control design was used to investigate the association between migration, urbanisation and schistosomiasis in the Metropolitan Region of Recife, Northeast of Brazil. 1022 cases and 994 controls, aged 10 to 25, were selected. The natives and the migrants who come from endemic areas have a similar risk of infection. On the other hand, the risk of infection of migrants from nonendemic areas seems to be related with the time elapsed since their arrival in São Lourenço da Mata; those who have been living in that urban area for 5 or more years have a risk of infection similar to that of the natives. Those arriving in the metropolitan region of Recife mostly emigrate from "zona da mata" and "zona do agreste" in the state of Pernambuco. Due to the changes in the sugar agro-industry and to the increase in the area used for cattle grazing these workers were driven to villages and cities. The pattern of urbanisation created the conditions for the establishment of foci of transmission in São Lourenço da Mata.

Serologic survey for hantavirus infections among wild animals in rural areas of São Paulo State, Brazil

A serosurvey was conducted in wild animals captured close to two areas where hantavirus cardiopulmonary syndrome (HCPS) occurred in São Paulo State, Brazil. Serum samples from a total of 43 mammals were tested for antibodies reactive with Sin Nombre (SN) hantavirus using a strip immunoblot assay. RNAs from the blood clots of the positive samples were submitted to reverse transcriptase-polymerase chain reaction (RT-PCR). Two rodents of the genus Oligoryzomys were positive for hantavirus antibodies. These animals were captured in the Iguape region and represented 16.7% (2/12) of the sera from rodents and 100.0% (2/2) of the Oligoryzomys captured in that area. RT-PCR failed to amplify any viral cDNA. These results are in agreement with other data that suggest that members of this genus are important reservoirs of hantaviruses in Brazil.

Haemoglobin and red cell counts in leptospirosis patients infected with different serovars

IntroductionThe aim of the study was to compare haemoglobin and red cell counts between patients known to be infected with a range of leptospiral serovars.MethodsThe study retrospectively compared the haemoglobin and red cell count results from the first blood samples taken from 207 patients at presentation to a Queensland Health hospital.ResultsSignificant differences were observed in haemoglobin and red cell counts in those infected with Leptospira interrogans serovars Szwajizak and Canicola when compared with most of the other serovars.ConclusionsThese findings suggest that haemoglobin and red cell counts may be useful in differentiating leptospiral serovars in leptospirosis patients.

Molecular phylogeny of the Myzorhynchella Section of Anopheles (Nyssorhynchus) (Diptera: Culicidae): genetic support for recently described and resurrected species

Phylogenetic relationships among species of the Myzorhynchella Section of Anopheles (Nyssorhynchus) were investigated using the nuclear ribosomal DNA second internal transcribed spacer (ITS2), the nuclear whitegene and mitochondrial cytochrome oxidase subunit I (COI) regions. The recently described Anopheles pristinus and resurrected Anopheles guarani were also included in the study. Bayesian phylogenetic analyses found Anopheles parvus to be the most distantly related species within the Section, a finding that is consistent with morphology. An. pristinus and An. guarani were clearly resolved from Anopheles antunesi and Anopheles lutzii, respectively. An. lutzii collected in the same mountain range as the type locality were found within a strongly supported clade, whereas individuals from the southern state of Rio Grande do Sul, tentatively identified as An. lutzii based on adult female external morphology, were distinct from An. lutzii, An. antunesi and from each other, and may therefore represent two new sympatric species. A more detailed examination of An. lutzii sensu latoalong its known geographic range is recommended to resolve these anomalous relationships.

Comparison of the infectivity of Trypanosoma cruzi insect-derived metacyclic trypomastigotes after mucosal and cutaneous contaminative challenges

Trypanosoma cruzi infects humans when infected triatomine vector excreta contaminate breaks in skin or mucosal surfaces. T. cruzi insect-derived metacyclic trypomastigotes (IMT) invade through gastric mucosa after oral challenges without any visible inflammatory changes, while cutaneous and conjunctival infections result in obvious local physical signs. In this study we compared the infectivity of T. cruzi IMT in mice after cutaneous and oral contaminative challenges simulating natural infections. The 50% infective dose (ID50) for oral challenge was 100 fold lower than the ID50for cutaneous challenge, indicating that oral mucosal transmission is more efficient than cutaneous transmission.

New host association: Polybia scutellaris (Hymenoptera, Vespidae) parasitized by Melaloncha (Diptera, Phoridae)

New host association: Polybia scutellaris (Hymenoptera, Vespidae) parasitized by Melaloncha (Diptera, Phoridae). The genus Melaloncha Brues is a large assemblage of New World, parasitoid phorid flies. They are parasitoids of Apoidea bees. However, here we present the first record of a wasp parasitized by Melaloncha sp. The new host is Polybia scutellaris (White), a neotropical eusocial wasp. The parasitized wasp was found in an urban park near the city of La Plata, Buenos Aires, Argentina. It appears that the genus Melaloncha parasitizes a wider range of social Hymenoptera than currently known.

Influence of soil pH on inorganic phosphorus sorption and desorption in a humid brazilian Ultisol

Liming is a common practice to raise soil pH and increase phosphorus (P) bioavailability in tropical regions. However, reports on the effect of liming on P sorption and bioavailability are controversial. The process of phosphorus desorption is more important than P sorption for defining P bioavailability. However few studies on the relationship between soil pH and P desorption are available, and even fewer in the tropical soils. The effects of soil pH on P sorption and desorption in an Ultisol from Bahia, Brazil, were investigated in this study. Phosphorus sorption decreased by up to 21 and 34 % with pH increases from 4.7 to 5.9 and 7.0, respectively. Decreasing Langmuir K parameter and decreasing partition coefficients (Kd) with increasing pH supported this trend. Phosphorus desorption was positively affected by increased soil pH by both the total amount of P desorbed and the ratio of desorbed P to initially sorbed P. A decreased K parameter and increased Kd value, particularly at the highest pH value and highest P-addition level, endorsed this phenomenon. Liming the soil had the double effect of reducing P sorption (up to 4.5 kg ha-1 of remaining P in solution) and enhancing P desorption (up to 2.7 kg ha-1 of additionally released P into solution).

Biomass and nutrient cycling in pure and mixed stands of native tree species in southeastern Bahia, Brazil

The objective of this paper is to study selected components of the nutrient cycle of pure and mixed stands of native forest species of Atlantic Forest in southeastern Brazil. Tree diameter, height, above-ground biomass, and nutrient content were determined in 22-year-old stands. Litterfall, litter decomposition, and nutrient concentration were evaluated from August 1994 to July 1995. The following species were studied: Peltogyne angustiflora, Centrolobium robustum, Arapatiella psilophylla, Sclerolobium chrysophyllum, Cordia trichotoma, Macrolobium latifolium. The litter of a natural forest and a 40-year-old naturally regenerated second-growth forest was sampled as well. The mixed-species outmatched pure stands in height, stem volume and total biomass (29.4 % more). The greatest amount of forest litter was observed in the natural forest (9.3 Mg ha-1), followed by the mixed-species stand (7.6 Mg ha-1) and secondary forest (7.3 Mg ha-1), and least litterfall was measured in the pure C. robustum stand (5.5 Mg ha-1). Litterfall seasonality varied among species in pure stands (CV from 44.7 to 91.4 %), unlike litterfall in the mixed-tree stand, where the variation was lower (CV 31.2 %). In the natural and second-growth forest, litterfall varied by 57.8 and 34.0 %, respectively. The annual rate of nutrient return via litterfall varied widely among forest ecosystems. Differences were detected between forest ecosystems in both the litter accumulation and quantity of litterlayer nutrients. The highest mean nutrient accumulation in above-ground biomass was observed in mixed-species stands. The total nutrient accumulation (N + P + K+ Ca + Mg) ranged from 0.97 to 1.93 kg tree-1 in pure stands, and from 1.21 to 2.63 kg tree-1 in mixed-species stands. Soil fertility under mixed-species stands (0-10 cm) was intermediate between the primary forest and pure-stand systems. The litterfall rate of native forest species in a mixed-species system is more constant, resulting in a more continuous decomposition rate. Consequently, both nutrient availability and quantity of organic matter in the soil are higher and the production system ecologically more sustainable.

Alocação de nutrientes em plantios de eucalipto no Brasil

Práticas de manejo florestal podem alterar a exportação de nutrientes do sítio. Este trabalho teve por objetivo estimar o conteúdo de nutrientes em árvores de eucalipto, em diferentes regiões do Brasil. Avaliou-se a influência de algumas características climáticas na produção e no conteúdo de nutrientes na biomassa, utilizando-se o banco de dados do Programa de Pesquisa em Solos e Nutrição de Eucalipto do Departamento de Solos - UFV. As características climáticas foram um importante componente dos modelos. A produção de biomassa e o conteúdo de nutrientes foram positivamente relacionados entre si e ambos foram menores nas regiões com menor disponibilidade de água. As estimativas apontaram que até à idade de 4,5 anos pós-plantio acumulam-se as maiores proporções de nutrientes (68 % do N, 69 % do P, 67 % do K, 63 % do Ca e 68 % do Mg) para a idade de corte de 6,5 anos. Isto indica que, após 4,5 anos, o potencial de resposta à aplicação de fertilizantes é menor. O conteúdo estimado de nutrientes acumulados na copa e na casca representou 65, 70, 64, 79 e 79 %, de N, P, K, Ca e Mg, respectivamente, até 6,5 anos de idade. Assim, a colheita apenas do lenho representa expressiva redução na exportação desses nutrientes proporcionando maior sustentabilidade da produção nas plantações de eucalipto.

Bernstein, Dukheim e a sociologia da educação na Inglaterra

Neste texto o autor procura elucidar o modo pelo qual Basil Bernstein utilizou e enriqueceu a contribuição de Durkheim para a análise de questões abordadas pela sociologia da educação.

Redução da influência da massa específica na determinação do teor de umidade de sementes de trigo

A medição da capacitância e da condutância de um capacitor contendo amostras de trigo permite a determinação de duas de suas propriedades dielétricas: a permissividade relativa (épsilon') e o fator de perda dielétrica (épsilon"). A utilização dessas propriedades, medidas simultaneamente em duas freqüências de oscilação do campo elétrico, permite reduzir ou eliminar o efeito da massa específica aparente na determinação do teor de umidade do trigo. Tal procedimento torna possível o monitoramento contínuo e em tempo real, sem a necessidade de retirar amostras, do teor de umidade de uma coluna de grãos em movimento, situação em que ocorrem as maiores variações na massa específica do produto. O objetivo deste trabalho consistiu na obtenção de equações que permitam reduzir ou eliminar o efeito da massa específica na determinação em linha do teor de umidade do trigo. Foram utilizadas amostras das variedades Hussar, Mercia e Hereward com teor de umidade entre 11% e 22% b.u. e massa específica no intervalo 666 kg m-3 <= ro <= 873 kg m-3. A equação que apresentou melhor desempenho permite calcular o teor de umidade do trigo com erros-padrão de calibração e de predição de 0,4 e 0,5 ponto percentual, respectivamente.

Carbon isotope discrimination and yield of upland rice as affected by drought at flowering

Field experiments involving upland rice genotypes, sown in various dates in late season, were carried out to assess the relationship of carbon isotope discrimination with grain yield and drought resistance. In each one of the three years, one trial was kept under good water availability, while other suffered water shortage for a period of 18-23 days, encompassing panicle emergence and flowering. Drought stress reduced carbon isotope discrimination measured on soluble sugars (deltas) extracted from stem uppermost internode at the end of the imposition period, but had relatively less effect on bulk dry matter of leaves, sampled at the same period, or that of uppermost internodes and grains, sampled at harvest. The drought-induced reduction in deltas was accompanied of reduced spikelet fertility and grain yield. In the three trials subjected to drought, genotypes with the highest yield and spikelet fertility had the lowest deltas. However, this relationship was weak and it was concluded that deltas is not a sufficiently reliable indicator of rice drought resistance to be useful as a screening test in breeding programs. On the other hand, grain yield and spikelet fertility of genotypes which were the soonest to reach 50% flowering within the drought imposition period, were the least adversely affected by drought. Then, timing of drought in relation to panicle emergence and to flowering appeared to be a more important cause of yield variation among genotypes than variation in deltas.

Inoculation methods under greenhouse conditions for evaluating soybean resistance to sudden death syndrome

The objectives of this work were to evaluate two greenhouse screening methods for sudden death syndrome (SDS) and to determine which one is best correlated with field resistance of soybean genotypes. The evaluations were done with three sets of genotypes that were classified as partially resistant, intermediate, and susceptible to SDS based on previous field evaluations. These three sets were independently evaluated for greenhouse SDS reactions using cone and tray inoculation methods. Plants were infected using grains of white sorghum [Sorghum bicolor (L.) Moench] infested with Fusarium solani f. sp. glycines. Foliar symptom severity was rated 21 days after emergence. The cone and field SDS ratings were significantly correlated and ranged from 0.69 for set 1 to 0.51 for set 3. Correlations of SDS ratings of genotypes between field and greenhouse tray ratings were significant for set 1 and not significant for set 2. The cone method showed the highest correlation with field results and is recommended to screen soybean genotypes for SDS resistance.

Whole-body MRI: comprehensive evaluation on a 48-channel 3T MRI system in less than 40 minutes. Preliminary results

OBJECTIVE: To evaluate a comprehensive MRI protocol that investigates for cancer, vascular disease, and degenerative/inflammatory disease from the head to the pelvis in less than 40 minutes on a new generation 48-channel 3T system. MATERIALS AND METHODS: All MR studies were performed on a 48-channel 3T MR scanner. A 20-channel head/neck coil, two 18-channel body arrays, and a 32-channel spine array were employed. A total of 4 healthy individuals were studied. The designed protocol included a combination of single-shot T2-weighted sequences, T1-weighted 3D gradient-echo pre- and post-gadolinium. All images were retrospectively evaluated by two radiologists independently for overall image quality. RESULTS: The image quality for cancer was rated as excellent in the liver, pancreas, kidneys, lungs, pelvic organs, and brain, and rated as fair in the colon and breast. For vascular diseases ratings were excellent in the aorta, major branch vessel origins, inferior vena cava, portal and hepatic veins, rated as good in pulmonary arteries, and as poor in the coronary arteries. For degenerative/inflammatory diseases ratings were excellent in the brain, liver and pancreas. The inter-observer agreement was excellent. CONCLUSION: A comprehensive and time efficient screening for important categories of disease processes may be achieved with high quality imaging in a new generation 48-channel 3T system.