Caldera unrest driven by CO2-induced drying of the deep hydrothermal system

Interpreting volcanic unrest is a highly challenging and non-unique problem at calderas, since large hydrothermal systems may either hide or amplify the dynamics of buried magma(s). Here we use the exceptional ground displacement and geochemical datasets from the actively degassing Campi Flegrei caldera (Southern Italy) to show that ambiguities disappear when the thermal evolution of the deep hydrothermal system is accurately tracked. By using temperatures from the CO2-CH4 exchange of 13C and thermodynamic analysis of gas ascending in the crust, we demonstrate that after the last 1982-84 crisis the deep hydrothermal system evolved through supercritical conditions under the continuous isenthalpic inflow of hot CO2-rich gases released from the deep (~8 km) magma reservoir of regional size. This resulted in the drying of the base of the hot hydrothermal system, no more buffered along the liquid-vapour equilibrium, and excludes any shallow arrival of new magma, whose abundant steam degassing due to decompression would have restored liquid-vapour equilibrium. The consequent CO2-infiltration and progressive heating of the surrounding deforming rock volume cause the build-up of pore pressure in aquifers, and generate the striking temporal symmetry that characterizes the ongoing uplift and the post-1984 subsidence, both originated by the same but reversed deformation mechanism

The geothermal potential of Campanian volcanoes: evaluation and opportunities.

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Tectonic stress and renewed uplift at Campi Flegrei caldera, southern Italy: New insights from caldera drilling

Deep drilling is a key tool for the investigation of active volcanoes in the modern Earth Sciences, as this provides the only means to obtain direct information on processes that occur at depth. Data acquired from drilling projects are fundamental to our understanding of volcano dynamics, and for mitigation of the hazards they pose for millions of people who live close to active volcanoes. We present here the first borehole measurement of the stress field in the crust of Campi Flegrei (southern Italy), a large active caldera, and one of the highest risk volcanoes worldwide. Measurements were performed to depths of ∼500 m during a pilot study for the Campi Flegrei Deep Drilling Project. These data indicate an extensional stress field, with a minimum horizontal stress of ca. 75% to 80% of the maximum horizontal stress, which is approximately equal to the vertical stress. The deviation from lithostatic conditions is consistent with a progressive increase in applied horizontal stress during episodes of unrest, since at least 1969. As the stress field is evolving with time, the outcome of renewed unrest cannot be assessed by analogy with previous episodes. Interpretations of future unrest must therefore accommodate the possibility that Campi Flegrei is approaching conditions that are more favourable to a volcanic eruption than has previously been the case. Such long-term accumulation of stress is not expected to be unique to Campi Flegrei, and so might provide a basis for improved forecasts of eruptions at large calderas elsewhere

Atributos químicos do solo tratado com composto orgânico de carcaça e despojo de abate de caprinos e ovinos.

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Sensitivity of bovine blastocyst gene expression patterns to culture environments assessed by differential display RT-PCR.

The use of culture media to support the development of preimplantation embryos to the blastocyst stage is often associated with detrimental effects on normal development. These effects have been uncovered largely by investigating the phenotypic abnormalities displayed by fetuses and newborns derived from cultured preimplantation embryos. Research to understand the impact of culture on the embryonic developmental programme has focused on embryo metabolism, gene expression and genomic imprinting. We have used differential display RT-PCR to examine culture influences on global transcript pools in bovine embryos. Others have examined culture influences on candidate marker genes in cultured murine, ovine and bovine embryos. These studies have demonstrated that culture conditions influence the amount of marker gene transcripts and downregulate or induce the expression of novel genes during early development. Optimized defined culture media maintain embryonic gene expression patterns closely resembling those displayed by embryos derived in vivo. Preimplantation mammalian embryos display an impressive capacity to respond to the pressures that suboptimal culture environments place upon them. However, this plasticity operates within a defined range of tolerances. Continued research using molecular techniques will lead to increased understanding of developmental mechanisms causing culture-related phenotypic abnormalities in post-implantation embryos

Tamanho da amostra foliar para avaliação do estado nutricional e índice SPAD de capim-elefante irrigado para corte.

Resumo: compor a amostra promoverá a otimização da mão de obra, além de diminuir erros inerentes à recomendação e avaliação do estado nutricional. A coleta de folhas de forrageiras para a diagnose do estado nutricional é uma etapa importante para subsidiar a adubação, sendo o tamanho da amostra imprescindível para representar adequadamente a população de plantas a ser manejada. Assim, objetivou-se dimensionar o número de amostras de folhas para a diagnose do estado nutricional de capim-elefante irrigado para corte, bem como o índice de clorofila SPAD (Soil Plant Analysis Development). A avaliação foi realizada em capineira de capim-elefante, var. Cameroon, com irrigação fixa de baixa aspersão, em área localizada em Sobral-CE, em solo Neossolo fluvico. Coletaram-se 40 amostras simples, em zigue-zague, de maneira aleatória, escolhendo-se folhas recém-expandidas. As variáveis mensuradas foram os teores foliares de macro (N, P, K, Ca, Mg e S) e micronutrientes (B, Cu, Fe, Mn e Zn) e o índice indireto de clorofila, com auxílio de um clorofilômetro. Considerando aceitável um erro amostral de 10%, a coleta de amostras simples de 16 e 80 plantas, respectivamente, para macro e micronutrientes em capim-elefante seria adequada. Para a medida indireta da clorofila, 8 amostras são necessárias para obter um erro de 10%. [Leaf size sample to nutritional state and SPAD index evaluation in elephant grass irrigated under cuts management]. Abstract: The determination of the amount of sample units that will compose the sample express the optimization of the workforce, and reduce errors inherent in the report of recommendation and evaluation of nutritional status. The leaf collection for diagnosis of nutritional status is an important step, and the sample size necessary to adequately represent the population to be assessed. Thus, the objective was evaluation to the number simple design of leaf samples for the diagnosis of nutritional status of elephant grass irrigated for cutting and SPAD (Soil Plant Analysis Development) index. The study was conducted in elephant grass, with a low fixed sprinkler irrigation, in an area located in Sobral-CE in alluvial soil. It was collected 40 samples simple, randomly, choosing newly expanded leaves. The variables measured were foliar concentrations of macro (N, P, K, Ca, Mg and S) and micronutrients (B, Cu, Fe, Mn and Zn) and the indirect index of chlorophyll, using a chlorophyll meter. Considering an acceptable error of 10%, the collection of single samples of 16 and 80 plants, respectively, for macronutrients and micronutrients in elephant grass would be appropriate. For the indirect measurement of chlorophyll (SPAD index) 8 plants would be required to obtain a 10% error

First evidence of post-seismic deformation in the central Mediterranean: Crustal viscoelastic relaxation in the area of the 1980 Irpinia earthquake (Southern Italy)

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Two-photon final states in peripheral heavy ion collisions

We discuss processes leading to two photon final states in peripheral heavy ion collisions at RHIC. Due to the large photon luminosity we show that the continuum subprocess $\gamma \gamma \to \gamma \gamma$ can be observed with a large number of events. We study this reaction when it is intermediated by a resonance made of quarks or gluons and discuss its interplay with the continuum process, verifying that in several cases the resonant process ovewhelms the continuum one. It is also investigated the possibility of observing a scalar resonance (the $\sigma$ meson) in this process. Assuming for the $\sigma$ the mass and total decay width values recently reported by the E791 Collaboration we show that RHIC may detect this particle in its two photon decay mode if its partial photonic decay width is of the order of the ones discussed in the literature.Comment: 10 pages, 8 figure

Relações biométricas e índice SPAD do milho submetido a fontes e doses de nitrogênio na regiao Semiárida do Brasil.

Resumo: O correto manejo da adubação nitrogenada e o emprego de tecnologias agregadas visam o melhor aproveitamento do N pelas culturas, em especial a cultura do milho. Objetivou-se avaliar as variáveis biométricas e os teores de clorofila, através de medidas indiretas em folhas de milho, em função da aplicação de fertilizantes nitrogenados em diferentes doses. O estudo foi conduzido no campo experimental da Empresa Brasileira de Pesquisa Agropecuária (Embrapa/CNPC) em Sobral-CE. Os tratamentos consistiram de cinco fontes de nitrogênio: uréia; uréia + NBPT; uréia + polímero; uréia + inibidor enzimático; e uréia + capeamento com enxofre elementar, em três níveis de adubação nitrogenada em cobertura: 100%, 75% e 50% da dose recomendada para a cultura, aplicados em cobertura 30 dias após o plantio. Quando as plantas apresentavam-se 50% pendoadas, foram avaliadas quanto às características biométricas (altura; diâmetro do caule; número de folhas) e medidas indiretas de clorofila com o auxílio de um medidor portátil. A variedade estudada foi o milho Catingueiro, adaptado às condições Semiáridas. Pode-se constatar que as plantas apresentaram diferentes comportamentos para o índice SPAD, em função das doses e dos adubos utilizados. Houve diferença significativa para número de folhas, quando comparadas fontes e doses de adubos, em relação à testemunha sem adubação, evidenciando a importância da adubação nitrogenada para a cultura do milho

Efeitos da aplicação de composto orgânico de carcaça e despojo de abate de caprinos e ovinos em micronutrientes, enxofre e alumínio do solo.

Resumo: A compostagem é uma forma de minimizar os impactos ambientais e o uso do composto orgânico melhora as características físicas e químicas do solo. Com o objetivo de avaliar a aplicação de doses do composto de carcaça de caprinos e ovinos nos atributos químicos em um Latossolo, em condições controladas, foi conduzido experimento no Departamento de Solos e Adubos da FCAV/Unesp ? Jaboticabal com o composto gerado pela Embrapa Caprinos e Ovinos. As doses do composto foram: zero; metade da dose padrão; a dose padrão; uma vez e meia e, duas vezes a dose padrão de composto orgânico. Para a dose padrão foi considerada a aplicação de 200 kg ha-1 de N e a quantidade presente no nutriente no composto. O delineamento experimental foram cinco doses do composto, sendo: zero; 5; 10; 15 e 20 t ha-1 de resíduo, com quatro repetições e três unidades por parcela, totalizando 60 unidades experimentais. As unidades foram acondicionadas em um recipiente de polietileno, com capacidade de 250 dm-3, contendo solo juntamente com os diferentes tratamentos, mantida em condições ambiente. No prazo de 90 dias, o solo contido em cada recipiente foi seco ao ar, peneirado e analisado quimicamente para micronutrientes, enxofre e alumínio. Com os resultados obtidos procedeu-se a análise de variância. Houve aumento das concentrações de B e de S-SO4 2-, e para Fe e Mn houve diminuição da concentração com aplicação do composto