Advanced deep sea diving equipment

Design requirements are generated for a deep sea heavy duty diving system to equip salvage divers with equipment and tools that permit work of the same quality and in times approaching that done on the surface. The system consists of a helmet, a recirculator for removing carbon dioxide, and the diver's dress. The diver controls the inlet flow by the recirculatory control valve and is able to change closed cycle operation to open cycle if malfunction occurs. Proper function of the scrubber in the recirculator minimizes temperature and humidity effects as it filters the returning air

Between the historical languages and the reconstructed language : an alternative approach to the Gerundive + “Dative of Agent” construction in Indo-European

It is argued by Hettrich (1990) that the “dative of agent” construction in the Indo-European languages most likely continues a construction inherited from Proto-Indo-European. In two recent proposals (Danesi 2013, Luraghi 2016), it is argued that the “dative of agent” contains no agent at all, although the two proposals differ with regard to the reconstructability of the “dative of agent” construction. Luraghi argues that it is an independent secondary development from an original beneficiary function (cf. Hettrich 1990), while Danesi maintains that the construction is reconstructable for an earlier proto-stage. Elaborating on Danesi’s approach, we analyze gerundives with the “dative of agent” in six different Indo-European languages that bridge the east–west divide, namely, Sanskrit, Avestan, Ancient Greek, Latin, Tocharian, and Lithuanian. Scrutiny of the data reveals similarities at a morphosyntactic level, a semantic level (i.e. modal meaning and low degree of transitivity), and also, to some extent, at an etymological level. An analysis involving a modal reading of the predicate, with a dative subject and a nominative object, is better equipped to account for the particulars of the “gerundive + nominative + dative” construction than the traditional agentive/passive analysis. The proposal is couched within the theoretical framework of Construction Grammar, in which the basic unit of language is the Construction, i.e. a form–function correspondence, and no principled distinction between lexical items and complex syntactic structures is assumed. As these structures are by definition units of comparanda, required by the Comparative Method, they can be successfully utilized in the reconstruction of a proto-construction for Proto-Indo-European

The supply of deep-sea containerised shipping services in the northern italian port systems

In this paper, a review of deep-sea liner shipping services to/from Northern Italian ports is performed.The first section focuses on the analysis of statistical data regarding Italian foreing trade: with special reference to incoming and outcoming freight volumes transported by sea. The Italian import and export volumes with the rest of the world, during the years 2000 – 2010, are reported; in particular the trade by sea between Italy and Asia, in the years 2000 – 2010, is analysed. The development of containerised traffic at Italian ports, which represents the vast majority of global non-bulk freight flows, is shown. The statistics analysed show that the effects of the economic crisis are still in force, and the overall Italian maritime trade decreased in 2009, the year following the onset of the crisis, and rose again in 2010. In the second part of the paper deep-sea services in the northern Italian port systems have been considered. The list of deep-sea services and the values of the total DWT (deadweight tonnage, in thousands of tons) of the containerships departed (in the period of analysis: January 2011) from the North-Western Italian multiport gateway system are reported. The list of deep-sea services and the values of total DWT at the North-Easter Italian multiport gateway system is considered. The routes of containerships departed from North-Western Italian ports and the routes of containerships departed from North-Eastern Italian ports (North Adriatic Italian ports), in January 2011, are shown. The performed survey shows clearly that the main international routes connect Italian ports to the Red Sea and East Asia as well as to US ports. Other routes which connect Italian ports to South America, to Africa and to Oceania are only minor routes. North-western ports have several deep-sea departures, whereas Adriatic ports still play a minor role; the majority of the containerships directed to the Adriatic Sea refer to the Short Sea Shipping network. But it must be pointed out that the economic development of Central and Eastern EU countries and the extension of the Trans-European Transport Network towards the East could contribute to add and/or shift towards the Adriatic Sea some deep-sea services

Structure of the Antarctic plate by analysis of surface-wave group speed and a global Haar-wavelet model representation

The unique tectonic setting of the Antarctic plate — all surrounded by active ocean ridges, geodynamically stationary, and crossed by the largest asymmetric continental rift — make it a very interesting subject, that recently has received increased attention because of the International Polar Year (IPY). We present a seismic tomographic study targeted at improving the resolution of previous models, by virtue of an extended dataset and a multiresolution spherical-wavelet based model representation. We limit the present study to modeling laterally-varying fundamental-mode Rayleigh wave group speed, that is mainly related to the structure of crust and uppermost mantle. We use single-station dispersion analysis on the surface wave train to measure group arrival times of the Rayleigh-wave fundamental mode in the period range between 30 and 150 s. On each seismogram we iteratively apply a multiple filter – to identify group arrival times with frequency – and a phase-matched filter, to isolate the fundamental mode within the wave train. We then use dispersion measurements to compute two-dimensional maps of wave group speed in the region. We parameterize the Earth using nearly-orthogonal spherical Haar wavelets based on iterative subdivisions of the icosahedron. This representation is particularly suited to implement multi-resolution, as needed for a regional model embedded into a global one. The model shows with increased detail important features such as the narrow transition between cratonic structure in East Antarctica and accreted West Antarctica, separated by the Transantarctic Mountains bordering the rift. Inclusion of data from temporary experiments carried on within the IPY, as they become available, will locally further improve resolution

Seismic Anisotropy of the Victoria Land region, Antactica

We present shear-wave splitting results obtained from the analysis of core refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We use an eigenvalue technique to isolate the rotated and shifted shear-wave particle motion, in order to determine the best splitting parameters. Average values show clearly that dominant fast axis direction is NE-SW oriented, in accordance with previous measurements obtained around this zone. Only two stations, OHG and STAR show different orientations, with N-S and NNW-SSE main directions. On the basis of the periodicity of single shear-wave splitting measurements with respect to back-azimuths of events under study, we infer the presence of lateral and vertical changes in the deep anisotropy direction. To test this hypothesis we model waveforms using a cross-convolution technique for the cases of one and two anisotropic layers. We obtain a significant improvement on the misfit in the double layer case for the two stations. For stations where a multi-layer structure does not fit, we investigate lateral anisotropy changes at depth through Fresnel zone computation. We find that anisotropy beneath the Transantarctic Mountains (TAM) is considerably different from that beneath the Ross Sea. This feature influences the measurement distribution for the two permanent stations TNV and VNDA. Our results show a dominant NE-SW direction over the entire region, but other anisotropy directions are present and maybe interpreted in the context of regional tectonics

Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica)

We present shear-wave splitting results obtained from analysis of core refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We used eigenvalue technique to linearize the rotated and shifted shear-wave particle motion, in order to determine the best splitting parameters. A well-scattered distribution of single shear-wave measurements has been obtained. Average values show clearly that dominant fast axis direction is NE-SW oriented, accordingly with previous measurements obtained around this zone. Only two stations, OHG and STAR show different orientations, with N-S and NNW-SSE main directions. On the basis of the periodicity of single shear-wave splitting measurements with respect to back-azimuths of events under study, we inferred the presence of lateral and vertical changes in the deep anisotropy direction. To test this hypothesis we have modelling waveforms using a cross-convolution technique in one and two anisotropic layer's cases. We obtained a significant improvement on the misfit in the double layer case for the cited couple of stations. For stations where a multi-layer structure does not fit, we looked for evidences of lateral anisotropy changes at depth through Fresnel zone computation. As expected, we find that anisotropy beneath the Transantarctic Mountains (TAM) is considerably different from that beneath the Ross Sea. This feature influences the measurement distribution for the two permanent stations TNV and VNDA. Our results show a dominant NE-SW direction over the entire region, but other anisotropy directions are present and find an interpretation when examined in the context of regional tectonics

Joint geophysical observations of ice stream dynamics

Ice streams play a major role in the ice mass balance and in the reckoning of the global sea level; they have therefore been object of wide scientific interest in the last three decades. During the 21st Italian Antarctic Expedition, in the austral summer 2005-06, we deployed a joint seismographic and geodetic network in the area of the David Glacier, Southern Victoria Land. This campaign followed a similar experiment carried out in the same area during the austral summer 2003-04 with the deployment of a seismographic network that recorded significant microseismicity beneath the David Glacier, primarily occurring as a few small clusters. In the latest 2005-06 deployment, 7 seismographic stations and 3 GPS geodetic receivers operated continuously for a period of 3 months (November 2005-early February 2006) in an area of about 100x150 km2 around the David Glacier. We have carried out several analyses using the combined data sets. These included the examination of the temporal evolution in earthquake magnitude and location and also the contemporaneous observation of both seismic activity and surface kinematics of the ice stream to possibly correlate the recorded microseismicity with the movement of the glacier, affected by the Ross Sea tides. Here we present some details of the two temporary networks and preliminary results and implications

Recent extension driven by mantle upwelling beneath the Admiralty Mountains (East Antarctica)

Northern Victoria Land is located at the boundary between an extended, presumably hot, region (West Antarctic Rift System) and the thick, possibly cold, East Antarctic craton. The style and timing of Tertiary deformation along with relationships with the magmatic activity are still unclear, and contrasting models have been proposed. We performed structural and morphotectonic analyses at the NE termination of northern Victoria Land in the Admiralty Mountains area, where the relationship between topography, tectonics, and magmatism is expected to be well pronounced. We found evidence of two subsequent episodes of faulting, occurring concurrently with the Neogene McMurdo volcanism. The first episode is associated with dextral transtension, and it is overprinted by extensional tectonics during the emplacement of large shield alkaline volcanoes. Upper mantle seismic tomography shows that the extensional regime is limited to regions overlying a low-velocity anomaly. We interpret this anomaly to be of thermal origin, and have tested the role of largescale upwelling on lithosphere deformation in the area. The results of this integrated analysis suggest that the morphotectonic setting of the region and the magmatism is likely the result of upwelling flow at the boundary between the cold cratonic and the hot stretched province (WARS), at work until recent time in this portion of the northern Victoria Land

Enamel interproximal reduction during treatment with clear aligners: digital planning versus OrthoCAD analysis

Background The aim of the study was to compare the amount of interproximal enamel reduction (IPR) provided on ClinCheck software with the amount of IPR carried out by the orthodontist during treatment with clear aligners. Methods 30 subjects (14 males, 16 females; mean age of 24.53 +/- 13.41 years) randomly recruited from the Invisalign account of the Department of Orthodontics at the University of Rome "Tor Vergata" from November 2018 to October 2019, were collected according to the following inclusion criteria: mild to moderate dento-alveolar discrepancy (1.5-6.5 mm); Class I canine and molar relationship; full permanent dentition (excluding third molars); both arches treated only using Comprehensive Package by Invisalign system; treatment plan including IPR. Pre- (T0) and post-treatment (T1) digital models (.stl files), created from an iTero scan, were collected from all selected patients. The OrthoCAD digital software was used to measure tooth mesiodistal width in upper and lower arches before (T0) and at the end of treatment (T1) before any refinement. The widest mesio-distal diameter was measured for each tooth excluding molars by "Diagnostic" OrthoCAD tool. The total amount of IPR performed during treatment was obtained comparing the sum of mesio-distal widths of all measured teeth at T0 and T1. Significant T1-T0 differences were tested with dependent sample t-test (P < 0.05). Results In the upper arch, IPR was digitally planned on average for 0.62 mm while in the lower arch was on average for 1.92 mm. As for the amount of enamel actually removed after IPR performing, it was on average 0.62 mm in the maxillary arch. In the mandibular arch, the mean of IPR carried out was 1.93 mm. The difference between planned IPR and performed IPR is described: this difference was on average 0.00 mm in the upper arch and 0.01 in the lower arch. Conclusions The amount of enamel removed in vivo corresponded with the amount of IPR planned by the Orthodontist using ClinCheck software