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Several recent models that have been put forth to explain bradyseism at Campi Flegrei (CF), Italy, are discussed. Data obtained during long-term monitoring of the CF volcanic district has led to the development of a model based on lithological-structural and stratigraphic features that produce anisotropic and heterogeneous permeability features showing large variations both horizontally and vertically; these data are inconsistent with a model in which bradyseism is driven exclusively by shallow magmatic intrusions. CF bradyseism events are driven by cyclical magmatic-hydrothermal activity. Bradyseism events are characterized by cyclical, constant invariant signals repeating over time, such as area deformation along with a spatially well-defined seismogenic volume. These similarities have been defined as "bradyseism signatures" that allow us to relate the bradyseism with impending eruption precursors. Bradyseism is governed by an impermeable shallow layer (B-layer), which is the cap of an anticlinal geological structure culminating at Pozzuoli, where maximum uplift is recorded. This B-layer acts as a throttling valve between the upper aquifer and the deeper hydrothermal system that experiences short (1-102 yr) timescale fluctuations between lithostatic/hydrostatic pressure. The hydrothermal system also communicates episodically with a cooling and quasi-steady-state long timescale (103-104 yr) magmatic system enclosed by an impermeable carapace (A layer). Connectivity between hydrostatic and lithostatic reservoirs is episodically turned on and off causing alternatively subsidence (when the systems are connected) or uplift (when the systems are disconnected), depending on whether permeability by fractures is established or not. Earthquake swarms are the manifestation of hydrofracturing which allows fluid expansion; this same process promotes silica precipitation that seals cracks and serves to isolate the two reservoirs. Faults and fractures promote outgassing and reduce the vertical uplift rate depending on fluid pressure gradients and spatial and temporal variations in the permeability field. The miniuplift episodes also show "bradyseism signatures" and are well explained in the context of the short timescale process. [ABSTRACT FROM AUTHOR]

We present major and trace element data on clinopyroxene‐hosted, glassy melt inclusions (MIs) from a highly enriched (high 87Sr/86Sr = 0.71856) lava (ALIA‐D115‐18) from the Samoan hot spot. Following correction for post‐entrapment crystallization, the MIs are trachytic (62.6–65.4 wt% SiO2, 1.5–3.0 wt% MgO, and 7.2–10.6 wt% total alkalis (Na2O + K2O)) ALIA‐D115 lavas dredged off the submarine flanks of Savai'i Island, western Samoa have previously been suggested to exhibit binary endmember magma mixing between a mafic, low 87Sr/86Sr magma and an evolved, high 87Sr/86Sr magma (the Enriched Mantle 2 endmember; EM2). In major and trace element space, these ALIA‐D115 lavas form a mixing trend between more primitive Samoan shield lavas and the MIs of this study, suggesting the MIs could represent the EM2‐derived mixing endmember. Recent efforts to constrain the EM2 mixing endmember composition shows remarkable overlap with the MI compositions, supporting the argument they could represent the 87Sr/86Sr mixing endmember to the ALIA‐D115 lavas and are derived from the EM2 endmember. Additionally, one melt inclusion contains Fo73 olivines not in equilibrium with the trachytic melt, suggesting the melt interacted with a mafic magma prior to entrapment within host clinopyroxene. Projecting the ALIA‐D115 mixing trend in 87Sr/86Sr versus SiO2 and K2O space shows that the trend intersects an average MI composition at 87Sr/86Sr values of ∼0.725, thereby offering a window into more extreme compositions associated with the EM2 endmember. Plain Language Summary: Droplets of silicate melt (i.e. melt inclusions) captured in the mineral clinopyroxene were measured for their chemistry. The melt inclusions and their clinopyroxene hosts are found in one lava recovered from the submarine flanks of Savai'i Island—an oceanic island formed along the Samoan hot spot track. The melt compositions represent silicate liquids present during magma evolution beneath Samoa. Lavas erupted at Samoa uniquely show extreme chemical signatures associated with ancient continentally derived sediment that has been recycled into Earth's interior via subduction. These diagnostic recycled materials have subsequently been incorporated into the Samoan plume, although the composition and origin of this material remains enigmatic. The melt inclusions provide a window into the composition of this recycled material and this study shows the melt inclusions may have been derived from a sediment‐infiltrated source. Remarkably, mixing between the melt inclusions and other compositionally distinct lavas from Samoa can explain the range in chemistry of lavas dredged from Savai'i Island. The Samoan melt inclusions help us understand the origin and evolution of the source contributing to the volcanic rocks of the Samoan hotspot, and ultimately, the chemical evolution of the Earth's mantle. Key Points: Reconstructed clinopyroxene‐hosted melt inclusions from an enriched (high 87Sr/86Sr) Samoa hot spot lava are trachyticMelt inclusion chemical variability is not the result of post‐entrapment crystallization or diffusion, but represents magma heterogeneity upon captureThe melt inclusions are a mixing endmember for a suite of enriched Samoan lavas and may be evidence of Enriched Mantle two derived liquids [ABSTRACT FROM AUTHOR]

OBJECTIVE: About one-third of patients undergoing percutaneous coronary interventions (PCIs) for flow-limiting coronary stenosis continue to develop signs of myocardial ischemia (MI) during exercise stress test [EST], despite successful coronary revascularization. Coronary microvascular dysfunction is a likely major cause of the persistence of EST-induced MI in these patients. PATIENTS AND METHODS: We studied 15 patients (14 men, age 67±5 years) fulfilling the following strict inclusion criteria: (1) recent PCI (<6 months), with drug-eluting stent, of coronary artery stenoses for stable angina, with evidence of full success (no residual stenosis >20% in any vessel); (2) persistence of ST-segment depression induction during EST. After a basal investigation, patients received either ranolazine (375 mg bid) or isosorbide- 5-mononitrate (ISMN, 20 mg bid) for 3 weeks in a single-blind, randomized crossover study. Clinical assessment, symptom-limited EST, echocardiographic color-Doppler, with tissue-Doppler examination, and coronary microvascular dilator response to adenosine (CFR-ADO) and cold pressor test (CFR-CPT), assessed by transthoracic echo-Doppler, were obtained at baseline and the end of the 3-week therapy with each drug. RESULTS: Compared to both baseline and ISMN, ranolazine showed a longer time to 1 mm ST-segment depression (404±116 s vs. 317±98 and 322±70 s, respectively; p<0.01). No differences were observed in coronary microvascular function and diastolic left ventricular function between the 2 drugs and compared to baseline. CONCLUSIONS: Our data show that ranolazine, but not ISMN, improved time to ischemia during EST. This effect, however, was independent of any effects on coronary microvascular and diastolic function. [ABSTRACT FROM AUTHOR]

The accuracy of the Green-Kubo formulation for computing shear viscosity from equilibrium molecular dynamics simulations depends on the quality of the potential and on how the viscosity computation is carried out. We examine the role of the duration of the simulation, the number of particles used, and how the correlations are accumulated on the accuracy of the computed viscosity. We propose as a measure of the accuracy the standard deviation of five independently computed shear viscosity values based on independent components of the stress tensor. Using this measure, we examine the shear viscosity calculation for molten NaCl to determine the values of the run length, window width, and spacing between windows and obtain a good compromise between calculation time and viscosity quality. Significantly we note that even though viscosity can be calculated using relatively few particles, reducing state point uncertainty requires more, rather than less, particles. [ABSTRACT FROM AUTHOR]