Limestone assimilation and the origin of CO2 emissions at the Alban Hills (Central Italy): constraints from experimental petrology.

International audienceThe Alban Hills volcanic region (20 km south of Rome, in the Roman Province) emitted a large volume of potassic magmas (> 280 km3) during the Quaternary. Chemical interactions between ascending magmas and the ~7000-8000-m-thick sedimentary carbonate basement are documented by abundant high temperature skarn xenoliths in the eruptive products and have been frequently corroborated by geochemical surveys. In this paper we characterize the effect of carbonate assimilation on phase relationships at 200 MPa and 1150-1050°C by experimental petrology. Calcite and dolomite addition promotes the crystallization of Ca-rich pyroxene and Mg-rich olivine respectively, and addition of both carbonates results in the desilication of the melt. Furthermore, carbonate assimilation liberates a large quantity of CO2-rich fluid. A comparison of experimental versus natural mineral, glass and bulk rock compositions suggests large variations in the degree of carbonate assimilation for the different Alban Hills eruptions. A maximum of 15 wt% assimilation is suggested by some melt inclusion and clinopyroxene compositions; however, most of the natural data indicate assimilation of between 3 and 12 wt% carbonate. Current high CO2 emissions in this area most likely indicate that such an assimilation process still occurs at depth. We calculate that a magma intruding into the carbonate basement with a rate of ~1-2•106 m3/year, estimated by geophysical studies, and assimilating 3-12wt% of host rocks would release an amount of CO2 matching the current yearly emissions at the Alban Hills. Our results strongly suggest that present CO2 emissions in this region are the shallow manifestation of hot mafic magma intrusion in the carbonate-hosted reservoir at 5-6 km depth, with important consequences for the present-day volcanic hazard evaluation in this densely populated and historical area

Limestone assimilation by basaltic magmas: an experimental re-assessment and application to Italian volcanoes

International audienceThe results of an experimental study of limestone assimilation by hydrated basaltic magmas in the range 1050-1150°C, 0.1–500 MPa are reported. Alkali basalts doped with up to 19 wt% of Ca,Mg-carbonates were equilibrated in internally heated pressure vessels and the resulting phase relationships are described. The major effects of carbonate incorporation are: 1) generation of CO2-rich fluid phases; 2) change in liquidus phase equilibria; the crystallization of Ca-rich clinopyroxene is favored and the other phases (e.g. olivine, plagioclase), present in the absence of carbonate assimilation, are consumed. As a consequence of the massive clinopyroxene crystallization, the residual melt is strongly silica-depleted and becomes nepheline-normative. Compositional and mineralogical evolutions observed in Mt.Vesuvius eruptive products match those documented in our experiments with added carbonates, suggesting the possibility that carbonate assimilation increased during the last 25ka of activity. In Central-Southern Italy, carbonate assimilation at shallow levels probably superimposes on deeper source heterogeneities

Infinite Product Representations for Kernels and Iteration of Functions

We study infinite products of reproducing kernels with view to their use in dynamics (of iterated function systems), in harmonic analysis, and in stochastic processes. On the way, we construct a new family of representations of the Cuntz relations. Then, using these representations we associate a fixed filled Julia set with a Hilbert space. This is based on analysis and conformal geometry of a fixed rational mapping R in one complex variable, and its iterations

Representation Formulas for Hardy Space Functions Through the Cuntz Relations and New Interpolation Problems

We introduce connections between the Cuntz relations and the Hardy space H2 of the open unit disk D. We then use them to solve a new kind of multipoint interpolation problem in H2, where for instance, only a linear combination of the values of a function at given points is preassigned, rather than the values at the points themselves

Solvent Dynamics and Thermodynamics at the Crystal-Solution Interface of Ibuprofen

The choice of solvent is key in the manufacturing of solution-grown crystals due to the critical effect it can exert on their morphology. Here we set out to investigate the dynamics and thermodynamics of solvent molecules at the crystal-solution interface for the morphologically dominant crystal faces of ibuprofen. In particular, we evaluate how thermodynamically favourable the desorption of a solvent molecule is and estimate the rate of exchange of adsorbed solvent molecules with molecules from the bulk solution. This analysis is carried out for all four morphologically dominant crystal faces of ibuprofen {100}, {002}, {011} and {110}, and ten solvents, i.e. water, 1-butanol, toluene, cyclohexanone, cyclohexane, acetonitrile, trichloromethane, methanol, ethyl acetate and ethanol. Our work reveals that the structure of the solution and the exchange dynamics can be strongly dependent on both the crystal face and the solvent, i.e. the same solvent can show radically different structure when in contact with different faces, alternatively the same face can induce different structuring in different solvents. Moreover, we find particularly strong surface-solvent interactions for the {002} and {100} crystal faces in several of the solvents examined. We conclude that the role of desolvation in the growth process is solvent- and face-specific, and therefore it has the potential of impacting the crystal shape anisotropy. We provide a framework to rationalise this effect based on molecular simulations of the crystal/solution interface

Nutrition and AGE-ing: Focusing on Alzheimer’s Disease

Recently, the role of food and nutrition in preventing or delaying chronic disability in the elderly population has received great attention. Thanks to their ability to influence biochemical and biological processes, bioactive nutrients are considered modifiable factors capable of preserving a healthy brain status. A diet rich in vitamins and polyphenols and poor in saturated fatty acids has been recommended. In the prospective of a healthy diet, cooking methods should be also considered. In fact, cooking procedures can modify the original dietary content, contributing not only to the loss of healthy nutrients, but also to the formation of toxins, including advanced glycation end products (AGEs). These harmful compounds are adsorbed at intestinal levels and can contribute to the ageing process. The accumulation of AGEs in ageing (“AGE-ing”) is further involved in the exacerbation of neurodegenerative and many other chronic diseases. In this review, we discuss food’s dual role as both source of bioactive nutrients and reservoir for potential toxic compounds—paying particular attention to the importance of proper nutrition in preventing/delaying Alzheimer’s disease. In addition, we focus on the importance of a good education in processing food in order to benefit from the nutritional properties of an optimal diet

Le produzioni agricole nel 1985

Attività di osservatorio ; n.1/86- Indice #7- L'andamento della produzione 1985 e il contesto economico e politico generale #9- I prodotti #2

Piano provinciale di Alessandria : indicazioni per la commercializzazione e la trasformazione di alcuni prodotti agricoli

Quaderno ; n.41- Indice #4- Gli ortofrutticoli #7- Il vino #17- Le carni #2

Advanced Glycation end products (AGEs) in food: focusing on Mediterranean pasta

5Advanced glycation end products, also known as glycotoxins, are a diverse group of highly oxidant compounds with pathogenic significance in aged-chronic disease, including diabetes, cardiovascular disease and neurodegenerative disease. They are produced physiologically in the body when reducing sugar binds to a free amino acid group of macromolecules. Thus conditions such as hyperglycemia and/or oxidative stress can favor AGE product formation, contributing to ageing processes and the exacerbation of pathological states. Beside endogenous AGEs, dietary AGE intake contributes significantly to the body AGE pool. It assumes that if dietary AGE intake gets lower, any chronic disease, such as diabetes and cardiovascular disease can be ameliorated, and even cured. For this reason, recently great attention has been made on the identification and quantification of AGE products in the consumed foods. Here we reviewed some knowledge, found in literature, concerning the formation of AGEs in food, their gastrointestinal absorption, and their toxic effects. In addition original data on AGE content in the Mediterranean pasta was discussed in relation to their production processes and cooking time.openopenAbate, G.; Delbarba, A.; Marziano, M.; Memo, M.; Uberti, D.Abate, Giulia; Delbarba, Andrea; Marziano, Mariagrazia; Memo, Maurizio; Uberti, Daniela Letizi