Search

Objectives Multiple aspects of the metabolic syndrome (MetS) remain problematic. Here we assess the association between epidemic obesity and the other MetS traits, and MetS utility for cardiovascular disease (CVD) risk assessment. Methods Italian population-based Progetto CUORE data were used: 17 252 women and men ages 35–69 years, baseline 1984–1993, mean follow-up of 10 years, for nonfatal plus fatal CVD events. NCEP-ATP III criteria defined MetS. Results Epidemic obesity was strongly related to epidemic rates of the four other MetS traits. Only four of 16 possible MetS trait combinations were common; their CVD hazard ratios ranged from 1.21 to 1.70. In multivariate analyses MetS was no better than the sum of its parts in predicting CVD, important information was lost due to omission of non-HDL-C and smoking, and from considering MetS traits as yes/no variables. CVD risk prediction by MetS was less strong for men and no stronger for women than by classical risk factors (blood pressure, diabetes, serum cholesterol, smoking, overweight/obesity). Conclusions These findings are concordant with the inference that epidemic obesity importantly influences epidemic occurrence of the other MetS traits; they also indicate that use of MetS for CVD risk assessment has limitations and needs critical reconsideration.

Background. Previously reported time trends of myocardial infarction rates in the MONICA Brianza 35-64-year-old population showed a clear decline in coronary heart disease mortality, mostly attributable to concurrent reductions in myocardial infarction attack rates, and to a lesser extent in 28-day case fatality. The aims of this study were to estimate time trends in more recent years (up to 1997-1998) in the same population and in the same age range, and to assess the impact of myocardial infarction among 35-74-year-old residents, an age range never investigated before in Italy using standardized population-based registers. Methods. The myocardial infarction register in the Brianza population was resumed in 1997-1998, adopting the same standardized methods for data collection and classification of suspect coronary events as the WHO MONICA project, including the age group 65-74 years in addition to age groups usually covered. Age-specific and age-standardized rates of validated coronary mortality rates, of attack rates, and incidence rates and of 28-day case fatality were calculated. Time changes were estimated as the difference in rates. Results. In comparison to the rates among 35-64-year-old residents, the 35-74 age-standardized rates of coronary event mortality in the biennium are more than 3 times higher in women and more than twice in men. Similarly, the attack and incidence rates increased respectively from 243 to 381 and from 197 to 292 per 100 000 in men, from 38 to 107 and from 33 to 87 per 100 000 in women. Statistically significant reductions are observed in coronary death rates, myocardial infarction attack rates and 28-day case-fatality rates between 1993-1994 and 1997-1998 in men. Analogous but not statistically significant changes are reported for women. Conclusions. In the Brianza MONICA population in the second half of the 1990s, coronary event death rates continued to decrease. In contrast with trends observed in previous years, the prominent quote of the reduction is attributable to case-fatality rates in the acute phase

Cold and thermal waters were sampled on Vulcano Island from shallow wells in June 1995, June 1996 and January-February 1997; additional samples refer to a thermal spring, meteoric water from domestic cisterns and local seawater. The chemical and isotopic (hydrogen, oxygen, tritium and strontium in water, and sulfur and oxygen in sulfate ions) compositions show that: 1) the shallow hydrothermal system is formed by the mixing of waters of meteoric origin and various ages with crater-type fumarolic steam and gases (phreato-volcanic waters), with water rising from the geothermal reservoir expected to exist at depth (sulfate-chloride waters), and with steam and gases released from the geothermal reservoir itself (steam-heated-waters); 2) a major seawater contribution occurs only in water from a well exploited in the Togo-Togo Camping, that is locate very close to the shoreline; 3) dissolved sulfate mostly derives from oxidation of fumarolic/magmatic sulfur species, with minor sporadic contributions from seawater or from dissolution of secondary anhydrite; and 4) major changes in the chemical and isotopic compositions of the bulk groundwater system were not observed during the study period, and the appreciable variations in waters from few wells may be interpreted as due to changes in the mixing proportions of the endmembers or to direct rainwater dilution. Based on the present study and previous ones from literature, an updated geochemical model is proposed for the groundwater system at Vulcano and its relations with the crater and beach fumarolic fluids.

We have applied the LIBS technique to reveal the deuterium concentration in water samples obtained by mixing almost pure D2O with H2O.

The deuterium composition of natural waters, along with other isotopic and chemical data, is a fundamental parameter in geochemical studies. For example, 1) the deuterium concentrations in the water discharged from geothermal wells is useful to discriminate its possible source; 2) temporal variation of the deuterium content in the steam condensates from high-temperature volcanic fumaroles may indicate changes in the degassing mechanism from the related deep magma, or different contributions from shallow groundwater to the fumarolic conduits linked to changes (e.g. earthquake-induced) in the fracture permeability of the rocks. The deuterium content in a water sample is commonly obtained by a two-steps method. The water sample reacts with zinc shots at 450ºC to give hydrogen, that is subsequently transferred to the mass spectrometer for analysis. Recent preliminary applications of the LIBS technique by the Applied Laser Spectroscopy Laboratory at IFAM to deuterium-rich water samples revealed that the deuterium and hydrogen spectral lines can be easily distinguished if the deuterium concentration is higher than about 5 parts per hundred. More work will be necessary in the future to decrease this lower limit in the deuterium content.

A geothermal reservoir formed near the foot of the active crater of Vulcano Island mainly by condensation of magmatic vapor. Increases in the oxygen composition of the reservoir water are consistent with earthquake-induced increases in the contribution from delta(18)O-rich magmatic condensate to the geothermal reservoir. Subsequent (18)O exchanges during reactions between the highly reactive magmatic condensate and the local rocks at the temporarily increased reservoir temperature cause the reservoir water to shift to lighter (18)O values. These variations in the oxygen composition of the reservoir water are not reflected by the deuterium composition, as the deltaD value of the magmatic condensate released from the magma after the tectonic earthquakes approaches values very similar to that of the water in the geothermal reservoir.

On Vulcano Island, in southern Italy, numerous shallow wells have been drilled for domestic use at the foot of the active crater. The thermal water in the well which supplies water to the camp-site Camping Sicilia is a mixture of reservoir water and shallow steam-heated groundwater of meteoric origin. During 1986-1988, the only variations observed in the available isotopic and chemical compositions of the Camping Sicilia well water, which changed from the almost pure reservoir component to the almost pure steam-heated meteoric component, occurred just before two sequences of tectonic earthquakes recorded near thye island. After the seismic activity, the Camping Sicilia well water returned to its pre-earthquake composition. These changes in composition could be explained by the dilatancy-fluid diffusion model. According to this model, the observed variations in the Camping Sicilia well water composition could be the consequence of stress build-up prior to the seismic events, and stress reduction afterwards.

Preliminary study of the temporal variation of the isotopic composition of geothermal waters at Vulcano Island (Italy).

Interpretazione preliminare della composizione isotopica dell'acqua/vapore di sorgenti termali e fumarole in Islanda, Afar e Hawaii in base a dati di letteratura.

Preliminary study on the isotopic composition of 30 thermal waters collected in 1997 from shallow water wells located near the foot of the active crater at Vulcano Island, Italy.

Preliminary study on the isotopic composition of 42 thermal waters collected in 1996 from shallow water wells located near the foot of the active crater at Vulcano Island, Italy.

Preliminary study on the isotopic composition of 26 thermal waters collected in 1995 from shallow water wells located near the foot of the active crater at Vulcano Island, Italy.

On the active crater of Vulcano Island (Aeolian Islands, Italy) an intense fumarolic activity is observable, with maximum temperatures of about 600ºC. The figure plots the variations over time (1978-1988) in the isotopic composition of the vapor and in the temperature for two typical fumaroles, F1 (full circles) and F5 (open circles). The arrows indicate local swarms of very shallow earthquakes centered beneath the crater, due to fluid dynamics in the upper structures of the volcanic system. The isotopic data for the magmatic steam of Vulcano island yeild an estimate of original composition in the range of +8.0 to +9.0 delta(18)O and 0 to +10 deltaD (Bolognesi and D'Amore, 1992). The patterns in the figure suggest that, coincident with shallow seismic events, the permeability increased in the direction of the conduits which feed the fumaroles, favoring the introduction of meteoric water with very negative concentrations of delta(18)O and deltaD. Therefore: increase in meteoric water --> increase in flow of steam --> higher steam temperature and lower delta(18)O and deltaD. After the conclusion of periods of local seismic activity, the values of delta(18)O and deltaD gradually become more positive and the temperature values tend to diminish (1981-83, 1986-87). This can be explained by the fact that the scarcity or absence of local seismic activity allows for a gradual reduction in permeability due to the action of self-sealing processes in the access ways to the fumarolic conduits. Therefore, the meteoric component progressively decreases, and the isotopic values of the fumarolic vapor get closer to the delta(18)O and deltaD values characteristic of local magmatic steam. REFERENCES: Bolognesi L. and D'Amore F. (1992) Isotopic evidence of coexisting geothermal and active volcanic systems (Vulcano island, italy). In prep.

New isotopic analyses of fluids were performed in the Larderello field about 10 years after reinjection tests began, and the results compared with data obtained in the pre-reinjection period. Whereas the isotopic composition of the steam is clearly affected by mixing with injected waters in the vicinity of the reinjection sites only, the isotopic composition of the gases appears to be modified over much wider zones. The isotopic temperatures derived from H and C isotopic exchanges between gas molecules such as CO2, CH4, H2 and H2O were all lower than the values obtained from the same geothermometers in the pre-reinjection surveys. The presence of a liquid water phase in the reservoir and the local formation of new CO2 and H2 with a quite different isotopic composition from the relatively deep components, are both considered in the interpretation of the field data. The kinetics of the isotope exchange reactions involved in the considered geothermometers are also discussed.

The Campiglia low-temperature geothermal system covers an area of about 30 km2 in southern Tuscany (Italy), only 20 km southwest of the Larderello geothermal field. The region is characterized by a main thermal aquifer (densely fractured carbonate-evaporitic Mesozoic formations) that is generally confined, but does crop out in some places. The thermal springs emerge on the boundaries of these outcrops. Seven water-points (springs and wells) in the geothermal system were monitored for three years. All of the springs revealed seasonal variations in flow rate, but constant chemical and isotopic compositions. Two of the wells, on the contrary, revealed strong variation in water composition. On the basis of the geohydrological and geochemical data, we have identified two possible water sources for the hydrothermal system and hypothesized the flowpaths followed by the waters feeding the various water-points.

Studio preliminare della composizione isotopica di gas e vapore campionato alle fumarole della Solfatara di Pozzuoli (NA), sia su base interpretativa della loro genesi che geotermometrica.

Right three years ago, on May 1983, a Symposium on Geochemical Surveillance of Volcanic and Seismic Activity was held in Palermo, Italy. In that occasion Carapezza, presenting the first report, emphasized the importance of studying the signs of impending seismic and volcanic events. What are these precursory signs? Obviously any correlations between a certain phenomenon and anomalies appearing prior to this phenomenon can be considered "precursory". However, despite some successful attempts at predicting these events by geochemical methods in various parts of the world, this approach is still neglected. The role of geochemistry should, on the contrary, be expanded and integrated with other disciplines. Classic and isotopic geochemistry may, in fact, give useful indications not only by showing anomalies considered precursory signs, but giving also parameters which are necessary to hypothesize a model of the volcanic apparatus; such a model will constitute the basic reference to evaluate possible variations of studied parameters. Applying geochemical methodologies to Pozzuoli Solfatara fluids, conclusions about their genesis and deep temperatures have been drawn. Relative ratios between non-reactive chemical species in gaseous phase, nitrogen, argon and helium, indicate an origin related to a mixing between a crustal and a mantle component. Important contributions from air-saturated water to gas emissions are thus excluded, even considering that the Solfatara water vapor is of meteoric origin as shown by its isotopic compositions. Nearest permeable outcrops are the Mesozoic limestones surrounding the impervious outcrops of the Phlegraean area; their presence at depth in the fumarole zone is indicated by the carbon isotopic composition of carbon dioxide, then where outcropping they act as recharge area to the system. As a number of geothermal wells has been drilled in the zone it has been possible to verify the applicability of isotopic geothermometers and of some gas-geothermometers when applied by a particular method. As fluids, according to experimental evidence, seem to be in chemical equilibrium at depth, changes in such a situation should be detectable by monitoring the studied parameters.

The study of carbon, hydrogen and oxygen isotopes in the system CO2-H2-CH4-H2O in the Pozzuoli Solfatara has led to some interesting considerations: - the steam originates from meteoric water and not from seawater contained in the volcanites, as hypothesized by some authors. This modifies the hydrogeological model; - the water in the reservoir undergoes strong reactions at high temperatures with surrounding rock; - the absence of tritium indicates that the water remains in the underground for at least 30 years; - the isotope geothermometers indicate similar temperature intervals to those measured in the geothermal boreholes in the region. The D geothermometer for the pair H2-H2O, in particular, gives a temperature value for the productive horizons feeding the surface manifestations that is comparable with that calculated by other authors with geochemical geothermometers applied in a study of the thermal waters of the region. The same temperature indications can also be obtained from a computation of the equilibrium constant of the equation: CO2 + 4 H2 = CH4 + 2 H2O by using a new criterium for choosing the equilibrium pressure.