171 research outputs found
An anthropogenic origin of the "Sirente crater," Abruzzi, Italy
Abstractâ In this paper, we review the recent hypothesis, based mostly on geomorphological features, that a âŒ130 mâwide sag pond, surrounded by a saddleâshaped rim from the Sirente plain (Abruzzi, Italy), is the firstâdiscovered meteoritic crater of Italy. Subâcircular depressions (hosting ponds), with geomorphological features and size very similar to those exhibited by the main Sirente sag, are exposed in other neighboring intermountain karstic plains from Abruzzi. We have sampled presentâday soils from these sag ponds and from the Sirente sags (both the main "crater" and some smaller ones, recently interpreted as a crater field) and various Abruzzi paleosols from excavated trenches with an age range encompassing the estimated age of the "Sirente crater." For all samples, we measured the magnetic susceptibility and determined the Ni and Cr contents of selected specimens. The results show that the magnetic susceptibility values and the geochemical composition are similar for all samples (from Sirente and other Abruzzi sags) and are both significantly different from the values reported for soils contaminated by meteoritic dust. No solid evidence pointing at an impact origin exists, besides the circular shape and rim of the main sag. The available observations and data suggest that the "Sirente crater," together with analogous large sags in the Abruzzi intermountain plains, have to be attributed to the historical phenomenon of "transumanza" (seasonal migration of sheep and shepherds), a custom that for centuries characterized the basic socialâeconomical system of the Abruzzi region. Such sags were excavated to provide water for millions of sheep, which spent summers in the Abruzzi karstic high pasture lands, on carbonatic massifs deprived of natural superficial fresh water. Conversely, the distribution of the smaller sags from the Sirente plain correlates with the local pattern of the calcareous bedrock and, together with the characteristics of their internal structure, are best interpreted as natural dolines. In fact, reported radiocarbon ages for the formation of the main sag pond and of the smaller sags differ (significantly) by more than two millennia, thus excluding that they were all contemporaneously formed by a meteoritic impact
Harmony of transitions in assessing interpersonal motivations in transcripts analysis can discriminate between Adult Attachment Interview secure and disorganized individuals
SUMMARY. Aim. Assessing Interpersonal Motivations in Transcripts (AIMIT) is a validated coding system to assess the activation of interpersonal motivational systems (IMS) in the transcripts of psychotherapy sessions. The Transition Index (TI) is an AIMIT measure that reflects the levels of organisation, synchronisation and harmony amongst two or more IMS when they are rapidly shifting or simultaneously in the clinical dialogue. It is supposed to be a measure of integration and coherence of the patientâs state of mind within the psychotherapeutic sessions. It has also been hypothesized that low TI could be a marker for disorganization of attachment of the patient leading to difficulties in the therapeutic relationships and ruptures in the therapeutic alliance. In order to assess this hypothesis we tested its capability to discriminate between Adult Attachment Interview (AAI) organized and disorganized individuals. Methods. Two groups of 15 transcriptions of AAI matched for age and sex, one classified as free-autonomous and one as disorganized, were analysed by the AIMIT method. Results. Compared to organized individuals, disorganized patients at AAI reported lower TI scores (3.7±0.63 vs 3.0±0.53; F=2.98, p=0.005). Furthermore,
TI showed a good discriminant capability (Wilksâ Lambda=0.77, p=0.004). Discussion and Conclusion. This result seems to confirm the usefulness and reliability of AIMIT analysis in evaluating the interpersonal difficulties which often characterize the therapeutic relationship with disorganized attachment patient
Neogene and Quaternary geodynamic evolution of the Italian peninsula: the contribution of paleomagnetic data
Paleomagnetism has played an important role in the development of geodynamic models for the Italian peninsula. Paleomagnetic data from this area have been increasingly reported since the late 1960s, placing important constraints on geodynamics. A brief outline of the main concepts underlying a paleomagnetic study is provided in the first part of this paper. We also discuss the criteiia for the assessment of the reliability of paleomagnetic data. Finally,the data collected over the past 25 years in peninsular and insular Italy are synthetically reviewed, discussing the main implications for the geodynamic evolution of the Tyrrhenian - Apennines foreland system
The contribution of Palaeomagnetism in Volcanology for dating of Holocene eruptions and estimating the emplacement temperature of pyroclastic flows. Applications on Tenerife and El Hierro (Canary Islands) and on Volcán El Fuego (Guatemala)
Paleomagnetic Evidence for 25â15 Ma Crust Fragmentation of North Indochina (23â26°N): Consequence of Collision With Greater India NE Corner?
AbstractThe Cenozoic deformation of SE Asia is classically related to IndiaâAsia collision and Tibet Plateau rise, supposedly resulting in the southeastward drift of lithospheric blocks bounded by strikeâslip faults with displacements in the order of 1,000 km. Here we report on the paleomagnetism of 44 TriassicâCretaceous red bed sites from the northern Simao, Chuandian, and Lanping "blocks," along both sides of the Ailao ShanâRed River shear zone (north Indochina). In the Simao domain, remagnetization predates folding and subsequent 48â70° clockwise rotation of three 2â5 km wide subblocks separated by two unrotated blocks. A primary magnetization component from the Lanping domain center suggests variably clockwise rotated (up to 95° ± 24°) sites, interrupted by a 2â6 km wide block that is rotated counterclockwise by 27° ± 6°. Thus, the Lanping and Simao "blocks" are far from being rigid, being made of a mosaic of independently deforming subblocks, whose kinematics and association with documented tectonics are speculative. It is unclear whether both folding and widespread remagnetization were synchronous or diachronous across north Indochina, but (considering previously published results) strikeâslip activity along major shear zones, remagnetization, rotations, and crustal shortening overlapped within the 32â15 Ma time window, thus were likely genetically related. As opposed to previous models, we suggest that in early to midâCenozoic times, north Indochina was under the influence of oblique NeoâTethys subduction. Collision between the NE corner of Greater India and Indochina at ~30 Ma yielded ENEâWSW shortening and strikeâslip reactivation of preexisting faults, in turn fragmenting the crust into small, independently rotating, blocks
Volcanological evolution of Pantelleria Island (Strait of Sicily) peralkaline volcano: a review
Pantelleria volcano has a particularly intriguing evolutionary history intimately related to the peralkaline composition of its explosively erupted magmas. Due to the stratigraphic complexity, studies over the last two decades have explored either only the pre-Green Tuff ignimbrite volcanism or the post-Green Tuff activity. We here focus on the whole evolutionary history, detailing the achievements since the first pioneering studies, in order to illustrate how the adoption and integration of progressively more accurate methods (40Ar/39Ar, paleomagnetism, petrography, and detailed field study) have provided many important independent answers to unresolved questions. We also discuss rheomorphism, a distinct feature at Pantelleria, at various scales and possible evidence for multiple, now hidden, caldera collapses. Although the evolutionary history of Pantelleria has shown that each ignimbrite event was followed by a period of less intense explosivity (as could be the present-day case), new geochronological and geochemical data may indicate a long-term waning of volcanic activity
Inverse Modelling of the Reversely Magnetized, Shallow Plumbing System Hosting Oil Reservoirs of the Auca Mahuida Volcano (Payeina retroarc, Neuquén Basin, Argentina)
The Auca Mahuida volcano (2.03â0.88 Ma) located east of the Andean thrust front in the NeuquĂ©n basin (Argentina) hosts an oil system of thermogenic origin and is affected by the NWâSE striking-faults. Intrusive bodies and the underlying Jurassic sediments constitute the reservoir rocks. Aeromagnetic data collected in the Auca Mahuida area detected multiple dipolar magnetic anomalies, many of which have reverse polarity. Palaeomagnetic measurements on rock samples collected in the field together with available age determinations indicate that the reversely magnetized sources were mainly emplaced during the Matuyama reverse polarity chron while the normal polarity sources were emplaced during the Olduvai and/or Jaramillo subchrons. The location and geometry of the intrusive bodies is poorly known and the customary magnetic inversion is rendered difficult because of multiple natural remanent magnetization directions. To address these difficulties, a voxel inversion was applied to model the vector residual magnetic intensity (VRMI) transformation of the observed total magnetic intensity data. The modelling showed a 1.5âkm deep, subcircular ring-shaped intrusion below the summit of the volcano and a series of NWâSE elongated, fault-controlled intrusive bodies to depths up to 3â4âkm. Our results show that magnetic data and VRMI modelling help resolve the geometry of the shallow plumbing system of volcanoes with remanently magnetized sources, and estimate the depth and geometry of potential oil reservoirs in volcanic areas
Evaluation of Natural Language Tools for Italian: EVALITA 2007
EVALITA 2007, the first edition of the initiative devoted to the evaluation of Natural Language Processing tools for Italian, provided a shared framework where participants? systems had the possibility to be evaluated on five different tasks, namely Part of Speech Tagging (organised by the University of Bologna), Parsing (organised by the University of Torino), Word Sense Disambiguation (organised by CNR-ILC, Pisa), Temporal Expression Recognition and Normalization (organised by CELCT, Trento), and Named Entity Recognition (organised by FBK, Trento). We believe that the diffusion of shared tasks and shared evaluation practices is a crucial step towards the development of resources and tools for Natural Language Processing. Experiences of this kind, in fact, are a valuable contribution to the validation of existing models and data, allowing for consistent comparisons among approaches and among representation schemes. The good response obtained by EVALITA, both in the number of participants and in the quality of results, showed that pursuing such goals is feasible not only for English, but also for other languages
Portfolio selection problems in practice: a comparison between linear and quadratic optimization models
Several portfolio selection models take into account practical limitations on
the number of assets to include and on their weights in the portfolio. We
present here a study of the Limited Asset Markowitz (LAM), of the Limited Asset
Mean Absolute Deviation (LAMAD) and of the Limited Asset Conditional
Value-at-Risk (LACVaR) models, where the assets are limited with the
introduction of quantity and cardinality constraints. We propose a completely
new approach for solving the LAM model, based on reformulation as a Standard
Quadratic Program and on some recent theoretical results. With this approach we
obtain optimal solutions both for some well-known financial data sets used by
several other authors, and for some unsolved large size portfolio problems. We
also test our method on five new data sets involving real-world capital market
indices from major stock markets. Our computational experience shows that,
rather unexpectedly, it is easier to solve the quadratic LAM model with our
algorithm, than to solve the linear LACVaR and LAMAD models with CPLEX, one of
the best commercial codes for mixed integer linear programming (MILP) problems.
Finally, on the new data sets we have also compared, using out-of-sample
analysis, the performance of the portfolios obtained by the Limited Asset
models with the performance provided by the unconstrained models and with that
of the official capital market indices
Evaluation of Natural Language Tools for Italian: EVALITA 2007
EVALITA 2007, the first edition of the initiative devoted to the evaluation of Natural Language Processing tools for Italian, provided a shared framework where participants\u2019 systems had the possibility to be evaluated on five different tasks, namely Part of Speech Tagging (organised by the University of Bologna), Parsing (organised by the University of Torino), Word Sense Disambiguation (organised by CNR-ILC, Pisa), Temporal Expression Recognition and Normalization (organised by CELCT, Trento), and Named Entity Recognition (organised by FBK, Trento). We believe that the diffusion of shared tasks and shared evaluation practices is a crucial step towards the development of resources and tools for Natural Language Processing. Experiences of this kind, in fact, are a valuable contribution to the validation of existing models and data, allowing for consistent comparisons among approaches and among representation schemes. The good response obtained by EVALITA, both in the number of participants and in the quality of results, showed that pursuing such goals is feasible not only for English, but also for other languages
- âŠ