Volcanic and hydrothermal areas largely contribute to the natural emission of greenhouse gases to the atmosphere, although large uncertainties in estimating their global output still remain. ...Nevertheless, CO2 and CH4 discharged from hydrothermal fluid reservoirs may support active soil microbial communities. Such secondary processes can control and reduce the flux of these gases to the atmosphere. In order to evaluate the effects deriving from the presence of microbial activity, chemical and carbon (in CO2 and CH4) isotopic composition of interstitial soil gases, as well as diffuse CO2 fluxes, of three hydrothermal systems from Italy were investigated, i.e. (i) Solfatara crater (Campi Flegrei), (ii) Monterotondo Marittimo (Larderello geothermal field) and (iii) Baia di Levante in Vulcano Island (Aeolian Archipelago), where soil CO2 fluxes up to 2400, 1920 and 346 g m−2 day−1 were measured, respectively. Despite the large supply of hydrothermal fluids, 13CO2 enrichments were observed in interstitial soil gases with respect to the fumarolic gas discharges, pointing to the occurrence of autotrophic CO2 fixation processes during the migration of deep-sourced fluids towards the soil-air interface. On the other hand, (i) the δ13C-CH4 values (up to ~48‰ vs. V-PDB higher than those measured at the fumarolic emissions) of the interstitial soil gases and (ii) the comparison of the CO2/CH4 ratios between soil gases and fumarolic emissions suggested that the deep-sourced CH4 was partly consumed by methanotrophic activity, as supported by isotope fractionation modeling. These findings confirmed the key role that methanotrophs play in mitigating the release of geogenic greenhouse gases from volcanic and hydrothermal environments.
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•Greenhouse gases are released from hydrothermal systems through diffuse degassing.•Carbon in CO2 from soil gases is isotopically heavier than that from fumaroles.•CO2/CH4 ratios in soil gases are higher than those measured in fumarolic emissions.•Autotrophs and methanotrophs mitigate the release of geogenic greenhouse gases.•Microbes contribute to regulate CH4 (and CO2) emissions from hydrothermal areas.
In this study, the results of a continuous monitoring of (i) CO2 fluxes, and (ii) CO2 and CH4 concentrations and carbon isotopic ratios (δ13C-CO2 and δ13C-CH4) in air, carried out from 7 to 21 July ...2017 and from October 10 to December 15, 2017 in the city centre of Florence, are presented. The measurements were performed from the roof of the historical building of the Ximenes Observatory. CO2 flux data revealed that the metropolitan area acted as a net source of CO2 during the whole observation period. According to the Keeling plot analysis, anthropogenic contributions to atmospheric CO2 were mainly represented by vehicular traffic (about 30%) and natural gas combustion (about 70%), the latter contributing 7 times more in December than in July. Moreover, the measured CO2 fluxes were about 80% higher in fall than in summer, confirming that domestic heating based on natural gas is the dominant CO2 emitting source in the municipality of Florence. Even though the continuous monitoring revealed a shift in the δ13C-CO2 values related to photosynthetic uptake of atmospheric CO2, the isotopic effect induced by plant activity was restricted to few hours in October and, to a lesser extent, in November. This suggests that urban planning policies should be devoted to massively increase green infrastructures in the metropolitan area in order to counterbalance anthropogenic emissions. During fall, the atmospheric CH4 concentrations were sensibly higher with respect to those recorded in summer, whilst the δ13C-CH4 values shifted towards heavier values. The Keeling plot analysis suggested that urban CH4 emissions were largely related to fugitive emissions from the natural gas distribution pipeline network. On the other hand, δ13C-CH4 monitoring allowed to recognize vehicular traffic as a minor CH4 emitting source.
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•Reducing urban greenhouse gas emissions requires recognition of emitting sources.•Isotopic partitioning method was applied for source identification in Florence.•Florence acts as a net source of CO2 resulting from traffic and gas combustion.•Green infrastructures are not sufficient to counterbalance anthropogenic emissions.•CH4 emissions are mostly related to fugitive leakages from natural gas pipelines.
This study presents the chemical and isotopic compositions of hydrothermal gases from fumaroles discharging around Copahue volcano (Argentina). Gas samples, including those from two fumaroles at the ...active summit crater, were collected during 13 surveys carried out by different research teams from 1976 to February 2016. The time-series of H
2
, CO and light hydrocarbons showed episodic increases related to the main events of the last eruptive cycle that started on 19 July 2012. Concentration peaks were likely caused by enhanced input of hot magmatic fluids affecting the hydrothermal reservoir. These data contrast with the temporal variations shown by
Rc
/
Ra
and δ
13
C-CO
2
values in 2012–2014, which indicated an increasing input from a crustal fluid source. In 2015–2016, however, these isotopic parameters showed opposite trends; their composition became closer to that of the two summit fumaroles, which possibly corresponds to that of the deep magmatic-related end-member. The delayed and reduced compositional changes in the peripheral hydrothermal fluid discharge in response to the 2012–2016 eruptive events suggest that geochemical surveys of these emissions are unlikely to provide premonitory signals of volcanic unrest if the volcanic activity remains centered in the main crater. Instead, an instrument which is able to provide measurements of volcanic gases in the air (e.g. MultiGAS) may be used to detect changes at the summit crater. Otherwise, monitoring of seismic activity and ground deformation, as well as the periodic measurement of the chemistry of the water in the Rio Agrio, which is fed by thermal discharge from the summit crater, seem to represent the most reliable means of monitoring at Copahue. However, the relative compositional stability of the hydrothermal reservoir is a great advantage in terms of geothermal resource exploitation and could encourage new investments in the Copahue geothermal project which was abandoned in the 1990s.
Diatoms in the Pseudo‐nitzschia genus produce the neurotoxin domoic acid. Domoic acid bioaccumulates in shellfish, causing illness in humans and marine animals upon ingestion. In 2017, high domoic ...acid levels in shellfish meat closed shellfish harvest in Narragansett Bay, Rhode Island for the first and only time in history, although abundant Pseudo‐nitzschia have been observed for over 60 years. To investigate whether an environmental factor altered endemic Pseudo‐nitzschia physiology or new domoic acid‐producing strain(s) were introduced to Narragansett Bay, we conducted weekly sampling from 2017 to 2019 and compared closure samples. Plankton‐associated domoic acid was quantified by LC‐MS/MS and Pseudo‐nitzschia spp. were identified using a taxonomically improved high‐throughput rDNA sequencing approach. Comparison with environmental data revealed a detailed understanding of domoic acid dynamics and seasonal multi‐species assemblages. Plankton‐associated domoic acid was low throughout 2017–2019, but recurred in fall and early summer maxima. Fall domoic acid maxima contained known toxic species as well as a novel Pseudo‐nitzschia genotype. Summer domoic acid maxima included fewer species but also known toxin producers. Most 2017 closure samples contained the particularly concerning toxic species, P. australis, which also appeared infrequently during 2017–2019. Recurring Pseudo‐nitzschia assemblages were driven by seasonal temperature changes, and plankton‐associated domoic acid correlated with low dissolved inorganic nitrogen. Thus, the Narragansett Bay closures were likely caused by both resident assemblages that become toxic depending on nutrient status as well as the episodic introductions of toxic species from oceanographic and climatic shifts.
The antimicrobial activity on bacteria and fungi of increasing polarity extracts of
Rubus ulmifolius and that of some isolated constituents, quercetin-3-
O-β-
d-glucuronide; kaempferol-3-
O-β-
...d-glucuronide, gallic acid, ferulic acid and tiliroside was evaluated. The phenolic and tannins fractions showed an high antimicrobial activity.
Background
Assessment of hydration status is complex and difficult to detect in older persons. Different methods have been developed to determine hydration status in clinical settings, but their ...diagnostic accuracy remains questionable.
Aims
The aim of this study was to determine and compare the diagnostic accuracy of all methods routinely used in acute settings to detect dehydration in a cohort of hospitalized oldest-old persons, using as primary reference standard blood urea nitrogen (BUN) to creatinine ratio.
Methods
This retrospective study was conducted on 59 oldest-old subjects at hospital admission in an acute setting, with complete physical, biochemical, bioelectrical impedance analysis (BIA) and ultrasound assessment, including inferior vena cava diameters.
Results
Fifty-nine (45 women/14 men) subjects, with a mean age of 87.4 ± 5.9 years, were studied. Based on the value of the BUN/creatinine ratio, the whole population was divided into hyperhydrated (
n
= 10), normohydrated (
n
= 42), and dehydrated (
n
= 7) groups. Among parameters indicating the hydration status, serum sodium levels (
p
< 0.0001), serum chloride levels (
p
= 0.010), calculated plasma osmolarity (
p
< 0.0001), and fat mass (FM) (
p
= 0.030) differed significantly among groups. A ROC analysis showed that the highest and most significant value for dehydration detection was the calculated plasma osmolarity (AUC: 0.820,
p
= 0.013), which significantly correlated with clinical parameters including heart rate (
r
= 0.300;
p
= 0.021), capillary refill (
r
= 0.379;
p
= 0.013) and systolic blood pressure (
r
= − 0.261;
p
= 0.046).
Discussion
The measurement of calculated serum osmolarity is simple and inexpensive and may quickly provide high sensitivity and specificity indication of dehydration in hospitalized oldest-old persons.
Abstract
Background
The accuracy of currently available bleeding scores in patients on treatment with direct oral anticoagulants (DOACs) for venous thromboembolism (VTE) is undefined.
Purpose
In a ...prospective cohort of patients with VTE treated with DOACs, we evaluated the accuracy of the ATRIA, HAS-BLED, Kuijer, ORBIT, RIETE and VTE-BLEED risk scores in predicting major bleeding (according to ISTH definition).
Methods
The accuracy of different scores to correctly classify subjects into a defined risk category was assessed by the c-statistic.
Results
Overall, 1141 patients were evaluated and 1034 included in the study. The index event was pulmonary embolism in 509 patients (49.2%) and proximal deep vein thrombosis in the remaining patients (50.8%). During the 12-month study period, 26 major bleedings occurred in 25 patients (2.8% patient-year): 14 major bleedings occurred in the first 6 months of treatment and 12 from 6 to 12 months in the 654 patients remained on treatment.
In the 12-month study period, the VTE-BLEED score showed the best predictive value for bleeding complications (c-statistics 0.674, 95% CI 0.593–0.755). The lowest incidence of major bleeding (0.3%) was observed in the low risk category of VTE-BLEED which includes 38% of patients. The highest incidence of major bleeding (7.1%) was observed in the high-risk category of ORBIT which includes 10.9% of patients.
Conclusions
The VTE-BLEED score had the best accuracy in predicting major bleeding during treatment with DOACs for VTE. Whether the VTE-BLEED score can be used for decision making on anticoagulation should be tested in a management study.
The Colli Albani volcanic complex (Lazio, Italy) hosts areas characterized by anomalously high emissions of CO2-rich gases (e.g. Tivoli, Cava dei Selci, Tor Caldara, Solforata). The source of these ...gases is a regional aquifer within the Mesozoic carbonate rock sequences. These degassing zones release significant concentrations of H2S and other toxic gases (e.g. GEM: Gaseous Elemental Mercury, and Rn) and represent a serious hazard for local inhabitants, especially for those living at Cava dei Selci (near Rome, Italy), where the emitting areas are nested inside residential neighborhoods. In April 2016, a comprehensive geochemical survey was carried out in an abandoned stone quarry nearby the urban settlement aimed to: (i) investigate the gas composition from both punctual discharges and anomalously high diffuse soil degassing sites, and (ii) evaluate their environmental impact on the local air quality. The spatial distribution of the soil CO2 fluxes was mainly dependent on the local geostructural setting, whereas shallow secondary processes (e.g. oxidation and gas-water interaction) likely represent the main controlling factor on reactive and/or water-soluble gas species, such as CH4 and H2S. The total output of CO2 from the abandoned stone quarry accounted for 0.53% of total CO2 discharged from the whole Colli Albani volcanic district. The naturally emitted toxic gases (e.g. CO2, H2S, CH4, GEM) largely affect the air quality and pose a serious threat for the health of the local residents. A mobile multi-instrumental station able to continuously and simultaneously acquire CO2, H2S, SO2, CH4, GEM and CO was deployed to verify the concentrations of both the main deep-originated gas compounds and potential secondary gaseous contaminants (i.e. SO2) around and inside the urban settlement most exposed to the lethal gases. Hydrogen sulfide was found to be the most impacting gas, occasionally exceeding the 24-h air quality guideline for ambient air and causing odor annoyance at a distance up to more than 250 m downwind from the emitting area. In poorly ventilated basements, toxic gas accumulations up to hazardous levels were measured, producing anomalous outdoor air concentrations at the street level in front of the descending vehicular access to private garages and relatively far from the main emitting area. The geochemical survey, carried out via mobile station and soil gas measurements, resulted to be particularly efficient for evaluating the potential effects caused by gas emissions in inhabited areas. The multi-measurement approach adopted in the present study is of paramount importance for managing future urban development plans.
•Natural gas emissions and air quality at Cava dei Selci were investigated.•Processes in the soil affected diffuse emissions of endogenous gases.•A mobile multi-instrumental station (MMS) was deployed for air quality measurement.•H2S was the most impacting gas in the residential area.•The MMS is a pivotal tool for managing future monitoring and intervention plans.
The Domuyo volcanic complex (Neuquén Province, Argentina) hosts one of the most promising geothermal systems of Patagonia, giving rise to thermal manifestations discharging hot and Cl−-rich fluids. ...This study reports a complete geochemical dataset of gas and water samples collected in three years (2013, 2014 and 2015) from the main fluid discharges of this area. The chemical and isotopic composition (δD-H2O and δ18O-H2O) of waters indicates that rainwater and snow melting are the primary recharge of a hydrothermal reservoir located at relative shallow depth (400–600m) possibly connected to a second deeper (2–3km) reservoir. Reactive magmatic gases are completely scrubbed by the hydrothermal aquifer(s), whereas interaction of meteoric waters at the surface causes a significant air contamination and dilution of the fluid discharges located along the creeks at the foothill of the Cerro Domuyo edifice. Thermal discharges located at relatively high altitude (~3150ma.s.l.), namely Bramadora, are less affected by this process, as also shown by their relatively high R/Ra values (up to 6.91) pointing to the occurrence of an actively degassing magma batch located at an unknown depth. Gas and solute geothermometry suggests equilibrium temperatures up to 220–240°C likely referred to the shallower hydrothermal reservoir. These results, confirming the promising indications of the preliminary surveys carried out in the 1980′s, provide useful information for a reliable estimation of the geothermal potential of this extinct volcanic system, although a detailed geophysical measurements is required for the correct estimation of depth and dimensions of the fluid reservoir(s).
•Compositional data of thermal fluids from the Domuyo volcanic complex are reported.•Air contamination dilute most hydrothermal gases at the volcano foothill.•Gas geothermometry indicates reservoir temperatures up to 220°C.•Preliminary estimations of the potential for geothermal energy are confirmed.•A conceptual geochemical model for the hydrothermal system is proposed.
The composition of essential oils from leaves and flowers of two hybrids (Carlos and Florom 350) of
Helianthus annuus cultivated in Tuscany (Italy) was investigated. The compounds were identified ...using gas chromatography (GC)/mass spectrometry (MS) analyses. Sixty-nine compounds were identified in the essential oils of leaves and flowers of sunflower plants harvested in July. Significant percentage variations were recorded between the leaves and flowers oil content. The monoterpenes were the major compounds present in both essential oils examined. α-pinene content was higher in flowers (72.6%) than in leaves (28.6%). The content of sabinene was ∼2 times higher in leaves than in flowers. There were no significant differences between the essential oil composition of the oils obtained from the same organs of the two hybrids.
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