Alteration of volcanic deposits in the ANDRILL AND-1B core: Influence of paleodeposition, eruptive style, and magmatic composition

Alteration minerals, assemblages, and textures were studied in a 175-m-thick volcanic sequence found between 759.32 and 584.19 m below seafloor within the 1285-m-long ANDRILL (Antarctic Geological Drilling project) McMurdo Ice Shelf core (MIS AND-1B). Three main alteration zones were identified through the application of different analytical methods (optical and scanning electron microscopy, electron microprobe, and X-ray diffraction). Alteration zoning is guided by the texture of the volcanic deposits, which is in turn determined by the eruptive style, transport mechanisms, and paleodepositional conditions. In particular, alteration reflects the evolution of paleodepositional conditions from submarine or shallow water to subaerial due to the growth of a nearby volcanic edifice. The general alteration trend is also influenced by the contribution of volcanogenic sediments derived from the reworking of silica-rich pyroclasts from earlier volcanic activity

Ostracod and Foraminifer Responses to Late Pleistocene–Holocene Volcanic Activity in Northern Victoria Land as Recorded in Ross Sea (Antarctica) Marine Sediments

The impacts on ostracods and foraminifers caused by three Late Quaternary ashfalls of different intensities and recovered in the ANTA02-NW2 core sediments (Drygalski Basin, western Ross Sea) were analysed for the first time. Albeit with different timing, both associations demonstrated similar response patterns associated with the deposition of material from volcanic eruptions. In particular, based on the palaeontological evidence, it was possible to divide the cores into four intervals/phases recording the evolution of the ecosystem before and after the deposition events: (1) Pre-extinction phase (high abundance and high diversity values). (2) Extinction phase, characterised by the complete disappearance of ostracod fauna; the foraminiferal assemblage, although not entirely absent, records extremely low values of abundance and diversity (survivor assemblage). (3) Recovery phase (increasing abundance and diversity values), characterised by the recolonisation of some opportunistic taxa; species such as Australicythere devexa and Australicythere polylyca dominate the ostracod assemblage. (4) Post-extinction phase (high abundance and high diversity values), with the return to an environmental equilibrium characterised by the colonisation of specialised taxa such as Argilloecia sp., Cytheropteron sp., Echinocythereis sp., and Hemicytherura spp. Our results may aid in the understanding of how communities (i.e., ostracods and foraminifers) recovered after the impact of direct deposits of volcanic ash into ocean waters. The mechanisms by which disappearance and/or mortality was induced are still not clear. The release of toxic metals during the reaction of the volcanic ash with seawater, the resulting chemical alteration in the seawater, and the change in pH, together with the possible suppression of planktonic organisms, may have caused the two main extinction phases recorded by the ANTA02-NW2 core sediments

Geosynchronous inclined orbits for high-latitude communications

© 2017. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/We present and discuss a solution to the growing demand for satellite telecommunication coverage in the high-latitude geographical regions (beyond 55°N), where the signal from geostationary satellites is limited or unavailable. We focus on the dynamical issues associated to the design, the coverage, the maintenance and the disposal of a set of orbits selected for the purpose. Specifically, we identify a group of highly inclined, moderately eccentric geosynchronous orbits derived from the Tundra orbit (geosynchronous, eccentric and critically inclined). Continuous coverage can be guaranteed by a constellation of three satellites in equally spaced planes and suitably phased. By means of a high-precision model of the terrestrial gravity field and the relevant environmental perturbations, we study the evolution of these orbits. The effects of the different perturbations on the ground track (which is more important for coverage than the orbital elements themselves) are isolated and analyzed. The physical model and the numerical setup are optimized with respect to computing time and accuracy. We show that, in order to maintain the ground track unchanged, the key parameters are the orbital period and the argument of perigee. Furthermore, corrections to the right ascension of the ascending node are needed in order to preserve the relative orientation of the orbital planes. A station-keeping strategy that minimizes propellant consumption is then devised, and comparisons are made between the cost of a solution based on impulsive maneuvers and one with continuous thrust. Finally, the issue of end-of-life disposal is discussed.Peer ReviewedPostprint (author's final draft

How do we treat the broad spectrum of patients with serious mental illness who have committed crimes? The Law 81/2014: limits and problems

In Italia è in corso un processo di deistituzionalizzazione che non ha precedenti al mondo. Si stanno progressivamente svuotando gli Ospedali Psichiatrici Giudiziari che non sono mai stati riformati negli ultimi 80 anni. Questo processo sta venendo attuato tramite una stratificazione di norme senza una progettualità diversa dalla rapida chiusura di queste fatiscenti strutture. Ai Dipartimenti di Salute Mentale (DSM) sono richieste una molteplicità di compiti nuovi e fortemente specialistici, e una estensione del loro potere di controllo, senza che queste strutture siano organizzate in tale senso. Alcune delle norme recentemente varate, come la Legge 81 del 2014, per risolvere alcuni problemi derivanti dalle difficoltà di deistituzionalizzazione complicano, a nostro parere, diversi aspetti gestionali di questa popolazione di gravi pazienti psichiatrici, che comunque non è assimilabile alla normale utenza dei DSM.Vi è necessità di un intervento legislativo coordinato e pensato su una prospettiva a lungo termineIn Italy an ongoing process of deinstitutionalization unprecedented in the world is been enacted.The Judicial Psychiatric Hospitals, that were never reformed in the past 80 years, are now on the edge of their closure.This process is being implemented through a layering of rules that had no purpose other than the rapid closure of these structures.The Mental Health Departments have now the responsibility of a multiplicity of new and highly specialized tasks, and an extension of their power to control.There is no previous organization for these tasks in the Mental Health System. Some of the recently enacted laws,such as the Law 81 of 2014, are intented to solve some problems, althought issues of deinstitutionalization are getting worse.In our opinion several management aspects of this population of severe psychiatric patients are unfit with the present organization of the Mental Health Services.There is need for legislative action coordinated and based on a long-term perspective

From hot rocks to glowing avalanches: Numerical modelling of gravity-induced pyroclastic density currents and hazard maps at the Stromboli volcano (Italy)

Gravity-induced pyroclastic density currents (PDCs) can be produced by the collapse of volcanic crater rims or due to the gravitational instability of materials deposited in proximal areas during explosive activity. These types of PDCs, which are also known as “glowing avalanches”, have been directly observed, and their deposits have been widely identified on the flanks of several volcanoes that are fed by mafic to intermediatemagmas. In this research, the suitability of landslide numerical models for simulating gravity-induced PDCs to provide hazard assessmentswas tested. This work also presents the results of a back-analysis of three events that occurred in 1906, 1930 and 1944 at the Stromboli volcano by applying a depth-averaged 3Dnumerical code named DAN-3D. The model assumes a frictional internal rheology and a variable basal rheology (i.e., frictional, Voellmy and plastic). The numerical modelling was able to reproduce the gravity-induced PDCs' extension and deposit thicknesses to an order ofmagnitude of that reported in the literature. The best resultswhen comparedwith field datawere obtained using a Voellmymodelwith a frictional coefficient of f=0.19 and a turbulence parameter ξ=1000 m s−1. The results highlight the suitability of this numerical code,which is generally used for landslides, to reproduce the destructive potential of these events in volcanic environments and to obtain information on hazards connected with explosive-related, mass-wasting phenomena in Stromboli Island and at volcanic systems characterized by similar phenomena.Published93-1065V. Dinamica dei processi eruttivi e post-eruttiviJCR Journa

Analysis of perturbations and station-keeping requirements in highly-inclined geosynchronous orbits

There is a demand for communications services at high latitudes that is not well served by conventional geostationary satellites. Alternatives using low-altitude orbits require too large constellations. Other options are the Molniya and Tundra families (critically-inclined, eccentric orbits with the apogee at high latitudes). In this work we have considered derivatives of the Tundra type with different inclinations and eccentricities. By means of a high-precision model of the terrestrial gravity field and the most relevant environmental perturbations, we have studied the evolution of these orbits during a period of two years. The effects of the different perturbations on the constellation ground track (which is more important for coverage than the orbital elements themselves) have been identified. We show that, in order to maintain the ground track unchanged, the most important parameters are the orbital period and the argument of the perigee. Very subtle changes in the orbital period (due mainly to lunar perturbations) cause a large east-west drift of the ground trace which dwarfs the displacement due to the regression of the ascending node. From these findings, a station-keeping strategy that minimizes propellant consumption has then been devised. Our results offer interesting guidelines for the design and operation of satellite constellations using these orbits.Postprint (author's final draft

Historical explosive activity of Mount Melbourne Volcanic Field (Antarctica) revealed by englacial tephra deposits

Five tephra layers named BRH1 to 5 were sampled in an ice cliff located on the north-eastern flank of Mount Melbourne (northern Victoria Land, Antarctica). The texture, componentry, mineralogy, and major and trace element compositions of glass shards have been used to characterize these layers. These properties suggest that they are primary fall deposits produced from discrete eruptions that experienced varying degrees of magma/water interaction. The major and trace element glass shard analyses on single glass shards indicate that Mount Melbourne Volcanic Field is the source of these tephra layers and the geochemical diversity highlights that the eruptions were fed by compositionally diverse melts that are interpreted to be from a complex magma system with a mafic melt remobilizing more evolved trachy-andesitic to trachytic magma pockets. Geochemical compositions, along with textural and mineralogical data, have allowed correlations between two of the englacial tephra and distal cryptotephra from Mount Melbourne, recovered within a marine sediment core in the Edisto Inlet (~ 280 km northeast of Mount Melbourne), and constrain the age of these englacial tephra layers to between the third and the fourth century CE. This work provides new evidence of the intense historical explosive activity of the Mount Melbourne Volcanic Field and better constrains the rates of volcanism in northern Victoria Land. These data grant new clues on the eruptive dynamics and tephra dispersal, and considerably expand the geochemical (major and trace elements) dataset available for the Mount Melbourne Volcanic Field. In the future, this will facilitate the precise identification of tephra layers from this volcanic source and will help define the temporal and spatial correlation between Antarctic records using tephra layers. Finally, this work also yields new valuable time-stratigraphic marker horizons for future dating, synchronization, and correlations of different palaeoenvironmental and palaeoclimatic records across large regions of Antarctica

Thermal analysis of the antineutrino 144Ce source calorimeter for the SOX experiment

The technical note describes the calorimeter which will be used to measure the activity of the antineutrino 144Ce source of the SOX experiment at the Gran Sasso Laboratories. The principle of the calorimeter is based on the measurement of both mass flow and temperature increase of the water circulating in the heat exchanger surrounding the source. The calorimeter is vacuum insulated in order to minimize the heat losses. The preliminary design and thermal Finite Element Analysis (FEA) are reported in the note

Do Diagnostic Nerve Blocks Affect the Starting Dose of Botulinum Neurotoxin Type A for Spasticity? A Case-Control Study

One of the aims of diagnostic nerve blocks is to identify the overactive muscles that lead to a specific spasticity pattern. However, to date, there is no evidence on how nerve blocks may affect botulinum neurotoxin-A (BoNT-A) dose in patients with spasticity. This case-control study aims to assess the role of diagnostic nerve block in defining BoNT-A starting dose at first treatment. Patients with upper and lower limb spasticity treated for the first time with BoNT-A were retrospectively divided into two groups: Group 1 (n = 43) was evaluated with clinical assessment and diagnostic nerve block; Group 2 (n = 56) underwent clinical assessment only. Group 1 was injected with higher BoNT-A doses in some muscles (i.e., flexor digitorum profundus, soleus), and received a higher BoNT-A cumulative dose with a larger number of injected muscles for some spasticity patterns (i.e., "clenched fist", "flexed fingers", "adducted thigh"). Diagnostic nerve block may help the clinician to optimize and personalize the BoNT-A dose since the first BoNT-A treatment