589 research outputs found
Urban floods: a case study in the Savigliano area (North-Western Italy)
Flood processes and effects are examined, concerning two rivers in an urbanized area in North-Western Italy (Piedmont – Cuneo Plain). In May 2008, some areas in Northern Italy were struck by intense and persistent rainfall. In the Cuneo province (Southern Piedmont), floodplain with some urban areas was inundated over ca. ten square kilometres, and the city of Savigliano (about 21 000 inhabitants) was particularly hit by flood. A purposely-made historical research has evidenced approximately fifty flood events as having occurred since 1350 in the Savigliano area. Based upon historical data, both documents and maps, GIS (Geographical Information System) technique and field surveys were used to quantitatively assess the growing urbanization of the city and to describe flood processes and effects over years. This work aims to describe the dynamic behaviour of the 2008 flood, also comparing it to past events, in particular those that occurred in 1896. It is emphasized how the knowledge of past events can be helpful in reducing urban flooding
Uncorrected land-use planning highlighted by flooding: the Alba case study (Piedmont, Italy)
Alba is a town of over 30 000 inhabitants located along the Tanaro River (Piedmont, northwestern Italy) and is famous for its wine and white truffles. Many important industries and companies are based in Alba, including the famous confectionery group Ferrero. <br><br> The town suffered considerably from a flood that occurred on 5–6 November 1994. Forty-eight percent of the urban area was inundated, causing severe damage and killing nine people. After the flood, the Alba area was analysed in detail to determine the reasons for its vulnerability. <br><br> Information on serious floods in this area since 1800 was gathered from official records, state technical office reports, unpublished documents in the municipal archives, and articles published in local and national newspapers. Maps, plans and aerial photographs (since 1954) were examined to reconstruct Alba's urban development over the last two centuries and the planform changes of the Tanaro River. <br><br> The results were compared with the effects of the November 1994 flood, which was mapped from aerial photographs taken immediately after the flood, field surveys and eyewitness reports. <br><br> The territory of Alba was subdivided into six categories: residential; public service; industrial, commercial and hotels; sports areas, utilities and standards (public gardens, parks, athletics grounds, private and public sport clubs); aggregate plants and dumps; and agriculture and riverine strip. The six categories were then grouped into three classes with different flooding-vulnerability levels according to various parameters. Using GIS, the three river corridors along the Tanaro identified by the Autorità di Bacino del Fiume Po were overlaid on the three classes to produce a final map of the risk areas. <br><br> This study shows that the historic floods and their dynamics have not been duly considered in the land-use planning of Alba. The zones that were most heavily damaged in the 1994 flood were those that were frequently affected in the past and sites of more recent urbanisation. Despite recurrent severe flooding of the Tanaro River and its tributaries, areas along the riverbed and its paleochannels have been increasingly used for infrastructure and building (e.g., roads, a municipal dump, a prison, natural aggregate plants, a nomad camp), which has often interfered with the natural spread of the floodwaters. Since the 1994 flood, many remedial projects have been completed along the Tanaro and its tributaries, including levees, bank protection, concrete walls and floodway channels. In spite of these costly projects, some areas remain at high risk for flooding. <br><br> The method used, which considered historical data, river corridors identified by hydraulic calculations, geomorphological aspects and land-use planning, can indicate with good accuracy flood-prone areas and in consequence to be an useful tool for the coherent planning of urban expansion and the mitigation of flood risk
Geo-hydrological risk mitigation in a terraced landscape: LiDAR data analysis in the Portofino natural Park, Italy
Modification of steep slopes with man-made terraces is an ancient and widespread habit in many areas of the world. If the modification assures agricultural practices in mountainous areas, it results even as an important interference with the geomorphic processes: important quantities of soil and sediments are subtracted to the degradation processes and, in case of total abandonment of terraces, they result again available to erosion. Intense rain event may cause partial instability or even collapse of the anthropogenic structures, configuring terraces as an additional source of Geo-hydrological hazard. Recent events in Liguria - northern Italy, in Cinque Terre 2011 and Leivi (Chiavari) 2014, caused damages and even casualties due to the sudden collapse of terraced slopes. A crucial point in assessing the potential hazard caused by abandoned terraced slopes is identifying their real extension. LiDAR data analysis is an important assessment tool particularly in strong steepness areas due to the capability of recognizing linear regular structures.
In the present research LiDAR data analysis has been used to identify terraces in the Portofino Natural Park area (Liguria region, Italy) as one of the preliminary activities of the RECONECT European Union\u2019s Horizon 2020 Research and Innovation Programme project. The project plans to realize nature based solutions to mitigate geohydrological risk in two pilot areas in the Portofino promontory and the recovery of terraces is one of the foreseen
actions. Mapping terraces is the first step to evaluate the potential risk associated to the possible instability processes and the interventions to be realized. Land use evolution in the area from 1800 to present have been indeed found through historical maps examination and used in conjunction with LiDAR analysis results
A spatial multicriteria prioritizing approach for geo-hydrological risk mitigation planning in small and densely urbanized Mediterranean basins
Landslides and floods, particularly flash floods, occurred recently in many
Mediterranean catchments as a consequence of heavy rainfall events, causing
damage and sometimes casualties. The high hazard is often associated with
high vulnerability deriving from intense urbanization, in particular along
the coastline where streams are habitually culverted. The necessary risk
mitigation strategies should be applied at the catchment scale with a holistic
approach, avoiding spot interventions.
In the present work, a high-risk area, hit in the past by several floods and
concurrent superficial landslides due to extremely localized and intense
rain events, has been studied. A total of 21 small catchments have been identified:
only some of them have been hit by extremely damaging past events, but all
lie in the intense-rain high-hazard area and are strongly urbanized in the
lower coastal zone. The question is what would happen if an intense rain
event should strike one of the not previously hit catchments; some situations
could be worse or not, so attention has been focused on the comparison
among catchments. The aim of the research has been identifying a priority
scale among catchments, pointing out the more critical ones and giving a
quantitative comparison tool for decision makers to support strong
scheduling of long-time planning interventions at the catchment scale. The past
events' effects and the geomorphic process analysis together with the field
survey allowed us to select three sets of parameters: one describing the
morphometric–morphological features related to flood and landslide hazard,
another describing the degree of urbanization and of anthropogenic
modifications at the catchment scale and the last related to the elements that
are exposed to risk. The realized geodatabase allowed us to apply the spatial
multicriteria analysis technique (S-MCA) to the descriptive parameters and
to obtain a priority scale among the analyzed catchments. The scale can be
used to plan risk mitigation interventions starting from the more critical
catchments, then focusing economic resources primarily on them and obtaining
an effective prevention strategy. The methodology could be useful even to
check how the priority scale is modified during the progress of the
mitigation work realization.
In addition, this approach could be applied in a similar context, even among
sub-catchments, after identifying a suitable set of descriptive parameters
depending on the active geomorphological processes and the kind of
anthropogenic modification. The prioritization would allow to invest
economic resources in risk mitigation interventions priory in the more
critical catchments.</p
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Time–frequency representation of autoionization dynamics in helium
Autoionization, which results from the interference between direct photoionization and photoexcitation to a discrete state decaying to the continuum by configuration interaction, is a well known example of the important role of electron correlation in light–matter interaction. Information on this process can be obtained by studying the spectral, or equivalently, temporal complex amplitude of the ionized electron wave packet. Using an energy-resolved interferometric technique, we measure the spectral amplitude and phase of autoionized wave packets emitted via the sp2+ and sp3+ resonances in helium. These measurements allow us to reconstruct the corresponding temporal profiles by Fourier transform. In addition, applying various time–frequency representations, we observe the build-up of the wave packets in the continuum, monitor the instantaneous frequencies emitted at any time and disentangle the dynamics of the direct and resonant ionization channels
Processing Ordinality and Quantity: The Case of Developmental Dyscalculia
In contrast to quantity processing, up to date, the nature of ordinality has received little attention from researchers despite the fact that both quantity and ordinality are embodied in numerical information. Here we ask if there are two separate core systems that lie at the foundations of numerical cognition: (1) the traditionally and well accepted numerical magnitude system but also (2) core system for representing ordinal information. We report two novel experiments of ordinal processing that explored the relation between ordinal and numerical information processing in typically developing adults and adults with developmental dyscalculia (DD). Participants made “ordered” or “non-ordered” judgments about 3 groups of dots (non-symbolic numerical stimuli; in Experiment 1) and 3 numbers (symbolic task: Experiment 2). In contrast to previous findings and arguments about quantity deficit in DD participants, when quantity and ordinality are dissociated (as in the current tasks), DD participants exhibited a normal ratio effect in the non-symbolic ordinal task. They did not show, however, the ordinality effect. Ordinality effect in DD appeared only when area and density were randomized, but only in the descending direction. In the symbolic task, the ordinality effect was modulated by ratio and direction in both groups. These findings suggest that there might be two separate cognitive representations of ordinal and quantity information and that linguistic knowledge may facilitate estimation of ordinal information
Bypass subclavio-axilar derecho por herida de arma de fuego
El trauma torácico es común en los pacientes politraumatizados, mas aun, en los heridos por arma de fuego, la identificación de la gravedad de las lesiones, y la habilidad para resolverlas de manera oportuna, sumadas a la disponibilidad de recursos, determina la sobrevida en estos pacientes. Presentamos el caso de un paciente de 19 años que ingresó a nuestro hospital con una herida de proyectil de arma de fuego, a nivel facial-cevical-torácico, con compromiso vascular arterio-venoso subclavio derecho, asociado a lesión pulmonar, el cual pudo ser resuelto quirúrgicamente de manera exitosa en nuestra institución, con evolución favorable y seguimiento a un año sin secuelas.Facultad de Ciencias Médica
A Prognostic Model for Estimating the Time to Virologic Failure in HIV-1 Infected Patients Undergoing a New Combination Antiretroviral Therapy Regimen
<p>Abstract</p> <p>Background</p> <p>HIV-1 genotypic susceptibility scores (GSSs) were proven to be significant prognostic factors of fixed time-point virologic outcomes after combination antiretroviral therapy (cART) switch/initiation. However, their relative-hazard for the time to virologic failure has not been thoroughly investigated, and an expert system that is able to predict how long a new cART regimen will remain effective has never been designed.</p> <p>Methods</p> <p>We analyzed patients of the Italian ARCA cohort starting a new cART from 1999 onwards either after virologic failure or as treatment-naïve. The time to virologic failure was the endpoint, from the 90<sup>th </sup>day after treatment start, defined as the first HIV-1 RNA > 400 copies/ml, censoring at last available HIV-1 RNA before treatment discontinuation. We assessed the relative hazard/importance of GSSs according to distinct interpretation systems (Rega, ANRS and HIVdb) and other covariates by means of Cox regression and random survival forests (RSF). Prediction models were validated via the bootstrap and c-index measure.</p> <p>Results</p> <p>The dataset included 2337 regimens from 2182 patients, of which 733 were previously treatment-naïve. We observed 1067 virologic failures over 2820 persons-years. Multivariable analysis revealed that low GSSs of cART were independently associated with the hazard of a virologic failure, along with several other covariates. Evaluation of predictive performance yielded a modest ability of the Cox regression to predict the virologic endpoint (c-index≈0.70), while RSF showed a better performance (c-index≈0.73, p < 0.0001 vs. Cox regression). Variable importance according to RSF was concordant with the Cox hazards.</p> <p>Conclusions</p> <p>GSSs of cART and several other covariates were investigated using linear and non-linear survival analysis. RSF models are a promising approach for the development of a reliable system that predicts time to virologic failure better than Cox regression. Such models might represent a significant improvement over the current methods for monitoring and optimization of cART.</p
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