236 research outputs found
magma and volatile supply to post collapse volcanism and block resurgence in siwi caldera tanna island vanuatu arc
V24C-04. Allen, S. R. (2005). Complex spatterand pumice-rich pyroclastic deposits from an andesitic caldera forming eruption: The Siwi pyroclastic sequence, Tanna, Vanuatu. Bulletin of Volcanology 67
Structural and functional heterogeneity of hemocyanin: intra- and inter-specific comparison in four species of portunid crabs (Crustacea: Portunidae)
This work is focused on hemocyanin (Hc)
heterogeneity at population level and on the biochemical
characterization of the different subunit patterns.
Two different approaches have been used: we
have characterized Hc subunit composition to describe
the subunit polymorphism. Then, we have measured
the Hc oxygen-binding affinity to disclose the physiological
implications of such heterogeneity. In order to
evaluate the intra- and inter-specific variability, different
populations of Liocarcinus depurator, Liocarcinus
marmoreus, Liocarcinus holsatus, Necora puber
(Crustacea: Portunidae), from British Isles and Adriatic
Sea, have been sampled. Results indicate that Hc
polymorphism normally occurs at both intra- and interspecific
levels and involves the protein subunit type.
These evidences extend to the portunid Hc the concept
of molecular heterogeneity within species that have
been previously reported for other decapod and
amphipod crustaceans. Besides, the results support the
view that subunit composition of crustacean Hcs is almost
species-specific, but also that closely related
species share a common pattern. Furthermore, this
heterogeneity corresponds to different stability of the
native oligomers quaternary structure and different
oxygen affinity. The results are discussed in relation
with the environmental regimes that characterize the
different sampling areas. In addition to Hc, the hemolymph
collected in specimens from different sampling
areas contained also a non-respiratory pseudo-Hc. This
paper reports for the first time the occurrence of
pseudo-Hc at the level of population
Small-scale spatial variability of soil CO2 flux: Implication for monitoring strategy
In recent decades, soil CO2 flux measurements have been often used in both volcanic and seismically active areas to investigate the interconnections between temporal and spatial anomalies in degassing and telluric activities. In this study, we focus on a narrow degassing area of the Piton de la Fournaise volcano, that has been chosen for its proximity and link with the frequently active volcanic area. Our aim is to constrain the degassing in this narrow area and identify the potential processes involved in both spatial and temporal soil CO2 variations in order to provide an enhanced monitoring strategy for soil CO2 flux. We performed a geophysical survey (self-potential measurements: SP; electrical resistivity tomography: ERT) to provide a high-resolution description of the subsurface. We identified one main SP negative anomaly dividing the area in two zones. Based on these results, we set ten control points, from the site of the main SP negative anomaly up to 230 m away, where soil CO2 fluxes were weekly measured during one year of intense eruptive activity at Piton de la Fournaise. Our findings show that lateral and vertical soil heterogeneities and structures exert a strong control on the degassing pattern. We find that temporal soil CO2 flux series at control points close to the main SP negative anomaly better record variations linked to the volcanic activity. We also show that the synchronicity between the increase of soil CO2 flux and deep seismicity can be best explained by a pulsed process pushing out the CO2 already stored and fractionated in the system. Importantly, our findings show that low soil CO2 fluxes and low carbon isotopic signature are able to track variations of volcanic activity in the same way as high fluxes and high carbon isotopic signature do. This result gives important insights in terms of monitoring strategy of volcanic and seismotectonic areas in geodynamics contexts characterized by difficult environmental operational conditions as commonly met in tropical areaPublished13-264A. Oceanografia e climaJCR Journa
Resistance to stress and Hc functional modulation in Liocarcinus sp
This study is included in a project aimed to study the alterations on the structure of the Northern Adriatic Sea ecosystem produced by
fishing activity. The indirect or secondary effects of fishery such as the changes of the structure and trophic relationships of the ecosystem are
under investigation and we have particularly considered the effects on species such as Liocarcinus depurator that are captured and then
rejected because devoid of commercial value.
The objective of this study is the Liocarcinus sp. adaptative resistance to stress and the effects of biochemical parameters (allosteric effectors)
on Hc functional modulation
Disease spreading with social distancing: A prevention strategy in disordered multiplex networks
The frequent emergence of diseases with the potential to become threats at local and global scales, such as influenza A(H1N1), SARS, MERS, and recently COVID-19 disease, makes it crucial to keep designing models of disease propagation and strategies to prevent or mitigate their effects in populations. Since isolated systems are exceptionally rare to find in any context, especially in human contact networks, here we examine the susceptible-infected-recovered model of disease spreading in a multiplex network formed by two distinct networks or layers, interconnected through a fraction q of shared individuals (overlap). We model the interactions through weighted networks, because person-to-person interactions are diverse (or disordered); weights represent the contact times of the interactions. Using branching theory supported by simulations, we analyze a social distancing strategy that reduces the average contact time in both layers, where the intensity of the distancing is related to the topology of the layers. We find that the critical values of the distancing intensities, above which an epidemic can be prevented, increase with the overlap q. Also we study the effect of the social distancing on the mutual giant component of susceptible individuals, which is crucial to keep the functionality of the system. In addition, we find that for relatively small values of the overlap q, social distancing policies might not be needed at all to maintain the functionality of the system.Fil: Pérez, Ignacio Augusto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones FÃsicas de Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones FÃsicas de Mar del Plata; ArgentinaFil: Di Muro, Matias Alberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones FÃsicas de Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones FÃsicas de Mar del Plata; ArgentinaFil: la Rocca, Cristian Ernesto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones FÃsicas de Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones FÃsicas de Mar del Plata; ArgentinaFil: Braunstein, Lidia Adriana. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones FÃsicas de Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones FÃsicas de Mar del Plata; Argentin
Intra-eruptive gas emissions and shallow magma storage after the 2007 summit caldera collapse of Piton de la Fournaise, Reunion island
Helminth Communities of Owls (Strigiformes) Indicate Strong Biological and Ecological Differences from Birds of Prey (Accipitriformes and Falconiformes) in Southern Italy
We compared the helminth communities of 5 owl species from Calabria (Italy) and evaluated the effect of phylogenetic and ecological factors on community structure. Two host taxonomic scales were considered, i.e., owl species, and owls vs. birds of prey. The latter scale was dealt with by comparing the data here obtained with that of birds of prey from the same locality and with those published previously on owls and birds of prey from Galicia (Spain). A total of 19 helminth taxa were found in owls from Calabria. Statistical comparison showed only marginal differences between scops owls (Otus scops) and little owls (Athene noctua) and tawny owls (Strix aluco). It would indicate that all owl species are exposed to a common pool of 'owl generalist' helminth taxa, with quantitative differences being determined by differences in diet within a range of prey relatively narrow. In contrast, birds of prey from the same region exhibited strong differences because they feed on different and wider spectra of prey. In Calabria, owls can be separated as a whole from birds of prey with regard to the structure of their helminth communities while in Galicia helminths of owls represent a subset of those of birds of prey. This difference is related to the occurrence in Calabria, but not Galicia, of a pool of 'owl specialist' species. The wide geographical occurrence of these taxa suggest that local conditions may determine fundamental differences in the composition of local communities. Finally, in both Calabria and Galicia, helminth communities from owls were species-poor compared to those from sympatric birds of prey. However, birds of prey appear to share a greater pool of specific helmith taxa derived from cospeciation processes, and a greater potential exchange of parasites between them than with owls because of phylogenetic closeness
Long-term outcome of COVID-19 patients treated with helmet noninvasive ventilation vs. high-flow nasal oxygen: a randomized trial
Background: Long-term outcomes of patients treated with helmet noninvasive ventilation (NIV) are unknown: safety concerns regarding the risk of patient self-inflicted lung injury and delayed intubation exist when NIV is applied in hypoxemic patients. We assessed the 6-month outcome of patients who received helmet NIV or high-flow nasal oxygen for COVID-19 hypoxemic respiratory failure. Methods: In this prespecified analysis of a randomized trial of helmet NIV versus high-flow nasal oxygen (HENIVOT), clinical status, physical performance (6-min-walking-test and 30-s chair stand test), respiratory function and quality of life (EuroQoL five dimensions five levels questionnaire, EuroQoL VAS, SF36 and Post-Traumatic Stress Disorder Checklist for the DSM) were evaluated 6 months after the enrollment. Results: Among 80 patients who were alive, 71 (89%) completed the follow-up: 35 had received helmet NIV, 36 high-flow oxygen. There was no inter-group difference in any item concerning vital signs (N = 4), physical performance (N = 18), respiratory function (N = 27), quality of life (N = 21) and laboratory tests (N = 15). Arthralgia was significantly lower in the helmet group (16% vs. 55%, p = 0.002). Fifty-two percent of patients in helmet group vs. 63% of patients in high-flow group had diffusing capacity of the lungs for carbon monoxide < 80% of predicted (p = 0.44); 13% vs. 22% had forced vital capacity < 80% of predicted (p = 0.51). Both groups reported similar degree of pain (p = 0.81) and anxiety (p = 0.81) at the EQ-5D-5L test; the EQ-VAS score was similar in the two groups (p = 0.27). Compared to patients who successfully avoided invasive mechanical ventilation (54/71, 76%), intubated patients (17/71, 24%) had significantly worse pulmonary function (median diffusing capacity of the lungs for carbon monoxide 66% [Interquartile range: 47–77] of predicted vs. 80% [71–88], p = 0.005) and decreased quality of life (EQ-VAS: 70 [53–70] vs. 80 [70–83], p = 0.01). Conclusions: In patients with COVID-19 hypoxemic respiratory failure, treatment with helmet NIV or high-flow oxygen yielded similar quality of life and functional outcome at 6 months. The need for invasive mechanical ventilation was associated with worse outcomes. These data indicate that helmet NIV, as applied in the HENIVOT trial, can be safely used in hypoxemic patients. Trial registration Registered on clinicaltrials.gov NCT04502576 on August 6, 202
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