Using cattle hair to assess exposure to essential trace elements in volcanic soils.

BACKGROUND: In areas where cattle graze outdoors, the environmental availability of trace elements is of utmost importance for an adequate intake. Cattle hair trace elements can be used as exposure biomarkers to assess animal intake and help ensure good nutrition and animal welfare. The aim of this study was to evaluate the environmental exposure to trace elements in cattle grazing outdoors in a volcanic region (São Miguel Island, Azores) and assess the corresponding bioaccumulation factors. METHODS: Twenty-nine samples of pasture topsoil were collected in two areas of São Miguel with different geological characteristics: Picos fissure system (basaltic area) and Povoação volcano (trachytic area). Hair from fifty-four animals (calves and dairy cows) was collected in two grazing sites: Ponta Delgada (Picos fissure system) and Povoação (Povoação volcano). All samples were analysed by inductively coupled plasma mass spectrometry (ICP-MS) after digestion in aqua regia. RESULTS: Basaltic soils of the Picos fissure system had significantly higher concentrations of most trace elements, except Mo, when compared with the trachytic soils of Povoação volcano. Hair of calves from Povoação showed higher concentrations of most essential trace elements, except Mg, Cu, and Zn, than hair from calves of Ponta Delgada (considered in this study as a control group since they are raised in a barn). On the other hand, hair from dairy cows grazing in Ponta Delgada showed higher concentrations of most essential trace elements, except Mg, As, and Mo, when compared with hair of cows grazing in Povoação. CONCLUSIONS: Cattle hair trace elements are suitable biomarkers for the assessment of the environmental exposure to trace elements in volcanic soils. The results from dairy cows support the uneven distribution of essential trace elements (and their bioavailability) in the different soils of São Miguel, reinforcing the need to graze animals outdoors from an early age. Such practice (grazing cattle outdoors) provides another means of accessing essential trace elements that complemented with feed can reduce the natural depletion of these essential elements in the body due to reproductive phenomena and milk production.

Deficiency of essential elements in volcanic soils: potential harmful health effects on grazing cattle.

Several essential nutrients such as Fe, Co, Cu, I, Se, and Zn are vital to grazing cattle as they play a significant role in intracellular enzyme systems, with antioxidant and repair functions of DNA lesions. Feeds may supply most essential nutrients in adequate amounts. However, essential nutrient deficiencies are common and are mainly related to the geochemical characteristics of the soils, inherited from parent rocks. This study aims to assess the concentrations of the selected essential nutrients in topsoils and pasture grass from São Miguel Island (Azores) and discuss the possible effects of its deficiency in grazing cattle health. Sixty-eight samples of agricultural (pastures) topsoil and thirty samples of pasture grass were collected throughout São Miguel Island in areas with basaltic and trachytic parent rocks. Soil physicochemical properties and geochemical baselines of selected elements were determined on composite samples of soil and pasture grass in each site. Results indicate that the highest concentrations of the selected essential nutrients were observed in areas with basaltic soils, while the lowest values were found in areas with trachytic soils. These differences are considered of geogenic origin since they result from the weathering of volcanic parent rocks with different geochemical compositions. Data indicate a lack of some essential nutrients in topsoils (Co and Se) and/or pasture grass (Co, Cu, Se, and Zn) that can contribute to harmful health effects on grazing cattle. The uneven distribution of essential nutrients in topsoil and pasture grass and their deficiency can lead to several health problems in the cattle since these elements regulate physiological functions in biological systems. The identification of these deficit sites is important as it can help farmers to implement soil and/or animal supplementation programs to diminish possible health problems.

Cobalt distribution in the soils of São Miguel Island (Azores): From volcanoes to health effects.

Volcanic soils cover only approximately 1% of the Earth's surface, yet they support 10% of the world's population due to their inherent fertility. However, deep magmatic processes may lead to depletion of certain elements in volcanic rocks. The imbalance of essential elements, such as cobalt, in soil parent materials can affect the health of plants and grazing animals and, thus, humans. Within the particular geological context of the Azores, the present study aims to assess cobalt concentration in volcanic soils to predict the risk of cobalt deficiency in animals and humans. Samples from agricultural topsoils and pasture grass were collected in six volcanic regions of São Miguel Island, and their physicochemical properties were measured, including selected transition metal element contents, such as iron, manganese and cobalt. The soil cobalt concentration was below 5 mg/kg in Povoação< Furnas/Congro< Sete Cidades< Fogo and was higher than 10 mg/kg in Picos< Nordeste. Cobalt concentrations were very low in pasture grass. Values below 0.1 mg/kg were observed in Furnas/Congro

Towards a 'Sea-Level Sensitive' dynamic model: impact of island ontogeny and glacio-eustasy on global patterns of marine island biogeography.

A synthetic model is presented to enlarge the evolutionary framework of the General Dynamic Model (GDM) and the Glacial Sensitive Model (GSM) of oceanic island biogeography from the terrestrial to the marine realm. The proposed 'Sea-Level Sensitive' dynamic model (SLS) of marine island biogeography integrates historical and ecological biogeography with patterns of glacio-eustasy, merging concepts from areas as diverse as taxonomy, biogeography, marine biology, volcanology, sedimentology, stratigraphy, palaeontology, geochronology and geomorphology. Fundamental to the SLS model is the dynamic variation of the littoral area of volcanic oceanic islands (defined as the area between the intertidal and the 50-m isobath) in response to sea-level oscillations driven by glacial-interglacial cycles. The following questions are considered by means of this revision: (i) what was the impact of (global) glacio-eustatic sea-level oscillations, particularly those of the Pleistocene glacial-interglacial episodes, on the littoral marine fauna and flora of volcanic oceanic islands? (ii) What are the main factors that explain the present littoral marine biodiversity on volcanic oceanic islands? (iii) How can differences in historical and ecological biogeography be reconciled, from a marine point of view? These questions are addressed by compiling the bathymetry of 11 Atlantic archipelagos/islands to obtain quantitative data regarding changes in the littoral area based on Pleistocene sea-level oscillations, from 150 thousand years ago (ka) to the present. Within the framework of a model sensitive to changing sea levels, we discuss the principal factors affecting the geographical range of marine species; the relationships between modes of larval development, dispersal strategies and geographical range; the relationships between times of speciation, modes of larval development, ecological zonation and geographical range; the influence of sea-surface temperatures and latitude on littoral marine species diversity; the effect of eustatic sea-level changes and their impact on the littoral marine biota; island marine species-area relationships; and finally, the physical effects of island ontogeny and its associated submarine topography and marine substrate on littoral biota. Based on the SLS dynamic model, we offer a number of predictions for tropical, subtropical and temperate volcanic oceanic islands on how rates of immigration, colonization, in-situ speciation, local disappearance, and extinction interact and affect the marine biodiversity around islands during glacials and interglacials, thus allowing future testing of the theory.

Enhancement of eruption explosivity by heterogeneous bubble nucleation triggered by magma mingling.

We present new evidence that shows magma mingling can be a key process during highly explosive eruptions. Using fractal analysis of the size distribution of trachybasaltic fragments found on the inner walls of bubbles in trachytic pumices, we show that the more mafic component underwent fracturing during quenching against the trachyte. We propose a new mechanism for how this magmatic interaction at depth triggered rapid heterogeneous bubble nucleation and growth and could have enhanced eruption explosivity. We argue that the data support a further, and hitherto unreported contribution of magma mingling to highly explosive eruptions. This has implications for hazard assessment for those volcanoes in which evidence of magma mingling exists.

Desenvolvimento do método indireto de aferição da pressão arterial e dos critérios de diagnóstico da hipertensão / Development of the indirect method of recording blood pressure and hypertension diagnosis criteria / Desarrollo del método indirecto de mensuración de la presión arterial y de los criterios de diagnostico de la hipertensión

INTRODUÇÃO: A hipertensão arterial é um grave problema de saúde pública, estando fortemente associada às doenças cardiovasculares, que são as principais causas de morte no mundo. OBJETIVO: Realizar revisão de literatura sobre o desenvolvimento do método indireto de aferição da pressão arterial, o diagnóstico e a classificação da hipertensão. METODOLOGIA: Levantamento bibliográfico nas bases de dados Lilacs, Scielo e Medline, usando os seguintes descritores: história e determinação da pressão arterial, de acordo com o MeSH e DECs. Foram selecionados 22 artigos científicos. Com relação aos critérios de diagnóstico da hipertensão, foram analisados relatórios sobre a doença, produzidos por organizações nacionais e internacionais de saúde. RESULTADOS: A aferição da pressão arterial iniciou-se com a utilização de aparelhos e técnicas invasivas e rudimentares, evoluindo ao longo dos anos para o desenvolvimento dos modernos esfigmomanômetros de coluna de mercúrio e digitais. Até o final da década de 1950, não havia critérios padronizados para o diagnóstico da hipertensão, os quais vieram a ser estabelecidos em decorrência do aumento do número de casos de morbimortalidade por doenças cardiovasculares. Atualmente, a hipertensão é definida como pressão arterial > 140/90 mmHg. CONCLUSÃO: O desenvolvimento do método indireto de aferição da pressão arterial e dos critérios de diagnóstico da hipertensão foi e permanece sendo um processo contínuo extremamente importante para os estudos sobre a fisiopatologia e os fatores de risco das doenças cardiovasculares.

INTRODUCTION: Hypertension, a serious public health problem, is highly associated to cardiovascular disease, main cause of worldwide death toll. OBJECTIVE: A literature review of the development of the indirect method of recording blood pressure and hypertension diagnosis criteria and classification. METHODS: Data was collected from bibliographic databases Lilacs, Scielo and Medline; key words: history and blood pressure determination, according to MeSH and DECs. 22 scientific articles were selected. Reports published by National and International Health Organizations were evaluated. RESULTS: The recording of blood pressure was first performed by invasive and rudimentary techniques; it evolved throughout the years to the modern mercury column and digital sphygmomanometers. Until the end of fifties there were no standardized criteria for hypertension diagnosis; these were established because of the increasing morbidity and mortality due to cardiovascular disease. Currently, hypertension is defined as blood pressure > 140/90 mmHg. CONCLUSION: The development of the indirect method of recording blood pressure and hypertension diagnosis criteria has been an ongoing process. It has been as well very important for studying the physiopathology and risk factors for cardiovascular disease.

INTRODUCCIÓN: La hipertensión arterial es un grave problema de la salud pública, estando fuertemente asociada a las enfermedades cardiovasculares, que son las principales causas de muerte en el mundo. OBJETIVO: Efectuar una revisión de la literatura sobre el desarrollo del método indirecto de mensuración de la tensión arterial, diagnóstico y clasificación de la hipertensión. METODOLOGÍA: Se realizó una búsqueda bibliográfica en las bases de datos Lilacs, Scielo y Medline, usando los descriptores: historia y determinación de la presión sanguínea, según el MeSH y DECs. Fueron seleccionados 22 artículos científicos. Respecto a los criterios de diagnóstico de la hipertensión, fueron analizados informes deorganizaciones nacionales e internacionales de salud. RESULTADOS: La presión sanguínea comenzó a medirse con aparatos y técnicas invasivas y rudimentarias y, con el tiempo, con los modernos esfigmomanómetros de columna de mercurio y digitales. Hasta los últimos años de la década del 50 del siglo pasado, no había criterios estandarizados para el diagnóstico de la hipertensión, lo cual fue establecido a causa del aumento de la morbi-mortalidad por enfermedades cardiovasculares. Actualmente, la hipertensión se define como presión sanguínea > 140/90 mmHg. CONCLUSIÓN: El desarrollo del método indirecto de mensuración de la presión sanguínea y de los criterios de diagnóstico de la hipertensión fue y sigue siendo un proceso continuo, muy importante para los estudios sobre la fisiopatología y los factores de riesgo de las enfermedades cardiovasculares.