1,506 research outputs found
Housing tenure choices with private information
We model the provision of owner-occupied versus rental housing services as a competitive search economy where households have private information over their expected duration. Owning solves the private information problem at the cost of double search. With public information, households with low vacancy hazard rates pay lower rents and search in thicker markets. With private information, housing is under-provided to long-duration households to discourage short-duration households from searching there. If a household has a high enough expected duration, rental distortions become large enough that she prefers to own. Customizing a house ameliorates the information problem while rent control exacerbates it
Tridactyl tracks from the Lavini di Marco dinosaur ichnosite (Hettangian, Southern Alps, NE Italy). Ichnotaxonomical review and palaeobiogeography
The use of aerial- and close-range photogrammetry for the mapping of the Lavini di Marco tracksite (Hettangian, Southern Alps, NE Italy)
(EXCERPT FROM ABSTRACT) Close-range photogrammetry was executed following the procedure proposed by Mallison & Wings (2014). More than seventy 3D models were obtained and interpreted by means of color-coded and contour line images, which allow to improve the ichno- logical knowledge of the tracksite. The 3D models of the best-preserved tracks were used for the osteological reconstruction of the trackmakers’ autopodia, supposing the arthral position of the phalangeal pads. Three indirect methods were used to correlate tracks and their trackmakers: (i) synapomorphy-based approach; (ii) phenetic correlation; (iii) coincidence correlation (see Carrano & Wilson, 2001)
The final map was produced with different level of knowledge due to the distribution of tracks and current state of site preservation. Furthermore, it represents a complete documentation that will be used for future work of enhancement, preservation and valorization of the tracksite.
The ichnotaxonomical review of the quadrupedal trackways led us to emend the diagnosis of Lavinipes cheminii Avanzini et al. (2003) and to assign several other sparse tracks and trackways to L. chemini. The skeletal reconstruction of fore and hind limbs points towards Gongxianosaurus sp. as the most suitable trackmaker of L. cheminii. The herein supposed Laurasian affinity of the Lavini di Marco dinosaur assemblage clashes with the previous hypotheses that always link the Southern Alps sector with the Gondwana mainland
Sistemi ambientali e Rete Natura 2000 della Regione Basilicata: scoprire e proteggere gli ambienti naturali e i paesaggi culturali della Lucania
Hippopotamid dispersal across the Mediterranean in the latest Miocene: A re-evaluation of the Gravitelli record from Sicily, Italy
The first dispersal of Hippopotamidae out of Africa is recorded around 6 Ma, but this event is documented only in a few European localities. Among them, the uppermost Miocene deposits of Gravitelli in Sicily yielded particularly abundant hippopotamid remains. These specimens, published at the beginning of the 20th century, went lost during the 1908 earthquake that destroyed the city of Messina. The specimens from Gravitelli were ascribed to a new species, Hippopotamus siculus; their generic attribution was not questioned during the first half of the past century and they have not been revised in recent decades. The remains of the Gravitelli hippopotamid were mainly represented by isolated teeth and a few postcranial remains. Morphological and dimensional characters of the specimens, such as long lower premolars, lowcrowned molars, a lower canine with longitudinal ridges and a groove on the lateral surface and the overall dimensions suggest that the Sicilian hippopotamid was characterized by plesiomorphic features. The morphology of the specimens collected from Gravitelli is similar to that of Hexaprotodon? crusafonti, Archaeopotamus harvardi, Hexaprotodon sivalensis and Hexaprotodon garyam. Hexaprotodon? siculus is also morphometrically similar to Hexaprotodon sivalensis, but the lower premolars in the former are longer and wider than in the latter. Accordingly, we provisionally refer the Gravitelli hippopotamid to the genus Hexaprotodon. Hexaprotodon? siculus is dimensionally different from the Spanish latest Miocene hippopotamid, herein referred to as Archaeopotamus crusafonti, and the two species are considered as valid taxa. The paleobiogeography of the latest Miocene hippopotamids from the Mediterranean Basin is discussed
Correction of sun glint effect on MIVIS data of the Sicily campaign in July 2000
To assess the suspended and dissolved matter in water in the visible and near infrared spectral regions it is necessary
to estimate with adequate accuracy the water leaving radiance. Consequently radiance measured by a remote
sensor has to be corrected from the atmospheric and the sea surface effects consisting in the path radiance
and the sun and sky glitter radiance contributions. This paper describes the application of the sun glint correction
scheme on to airborne hyperspectral MIVIS measurements acquired on the area of the Straits of Messina
during the campaign in July 2000. In the Messina case study data have been corrected for the atmospheric effects
and for the sun-glitter contribution evaluated following the method proposed by Cox and Munk (1954,
1956). Comparison between glitter contaminated and glitter free data has been made taking into account the radiance
profiles relevant to selected scan lines and the spectra of different pixels belonging to the same scan line
and located out and inside the sun glitter area. The results show that spectra after correction have the same profile
as the contaminated ones, although, at this stage, free glint data have not yet been used in water constituent
retrieval and consequently the reliability of such correction cannot be completely evaluated
Classification of submersed aquatic vegetation of the Venice lagoon using MIVIS airborne data
In July 2001 an aerial survey with MIVIS (Multispectral Infrared and Visible Spectrometer) hyperspectral sensor and
an in situ survey campaign were performed on Venice lagoon to map benthic macro-algae and sea phanerogams distribution.
On MIVIS VIS spectral range images, training areas for benthic macro-algae and sea phanerogams have
been selected by using sea truth data collected by CNR-ISMAR from in situ campaign and periodic area surveys
used in the lagoon by the local authorities. The derived spectral signature has been used to classify the area in order
to produce the maps of the pure and mixture submersed vegetation population. The algorithm applied to the data is
based on the Subpixel Spectral Analytical Process (SSAP) method. The method assumes that the spectrum of a single
pixel is composed of a fraction of the material of interest while the remainder of the observed spectra contains
background materials. In terms of recognition processes the produced maps present a very good agreement with the
sea truth data even though the fraction material expressed in the maps does not represent a quantitative estimation of
the material of interest
Relations between morphological settings and vegetation covers in a medium relief landscape of Central Italy
Morphometric units and vegetation classes were determined by applying two classification methods to the Soratte Mount area, a medium relief structure within the Italian Latium region. The study aims at defining the relationships between vegetation and landform types and highlighting the main morphological characteristics within examined land cover classes. These were the result of the application of a supervised classification method to the first 28 (VIS-NIR) bands of the airborne MIVIS data collected within an extensive survey campaign over Rome Province. The analysis was supported by photo-interpretation of peculiar MIVIS band combinations and by data acquired during field surveys and from a pre-existing vegetation map. The morphometric data were obtained by processing a raster DEM created from topographic maps. These data were processed by means of a new morphometric classification method based on the statistical multivariate investigation of local topographic gradients, calculated along the 8 azimuth directions of each pixel neighbourhood. Such approach quickly estimates the spatial distribution of different types of homogeneous terrain units, emphasizing the impact of erosional and tectonic processes on the overall relief. Mutual relations between morphometric units and vegetation types were assessed by performing a correspondence analysis between the results of the two classifications
Multiscale integration of satellite, airborne and field data for Mediterranean vegetation studies in the natural area of the Castelporziano Estate (Rome)
new experimental approach to land analysis has recently been developed, based on the integration of information
acquired on different scales; it enables the structure and the functionality of the vegetation in natural ecosystems
to be analysed. This research aims at assessing the potentiality of the experimental approach by the integration
of airborne and satellite remotely sensed data with ground measurements of structural parameters. In July
1999 a joint campaign for the acquisition of airborne (MIVIS, spatial resolution 3 m) and satellite remotely
sensed data (Landsat 5TM, spatial resolution 30 m) and measures taken at ground (PAI), was deployed in the
Presidential Estate at Castelporziano (Rome, Italy). The spectral signatures of the main vegetational types of the
Estate were examined and the PAI were related to NDVI values, calculated by means of satellite and airborne
images. The adopted approach enabled PAI maps to be produced. The linear relation between measured PAI and
estimated PAI showed a higher coefficient of determination when the MIVIS data were used. The sensor high
spectral resolution has moreover allowed to better describe the structural characteristics of the main plant typologies
at Castelporziano Estate
CNR LARA project, Italy: Airborne laboratory for environmental research
The increasing interest for the environmental problems and the study of the impact on the environment due to antropic activity produced an enhancement of remote sensing applications. The Italian National Research Council (CNR) established a new laboratory for airborne hyperspectral imaging, the LARA Project (Laboratorio Aero per Ricerche Ambientali - Airborne Laboratory for Environmental Research), equipping its airborne laboratory, a CASA-212, mainly with the Daedalus AA5000 MIVIS (Multispectral Infrared and Visible Imaging Spectrometer) instrument. MIVIS's channels, spectral bandwidths, and locations are chosen to meet the needs of scientific research for advanced applications of remote sensing data. MIVIS can make significant contributions to solving problems in many diverse areas such as geologic exploration, land use studies, mineralogy, agricultural crop studies, energy loss analysis, pollution assessment, volcanology, forest fire management and others. The broad spectral range and the many discrete narrow channels of MIVIS provide a fine quantization of spectral information that permits accurate definition of absorption features from a variety of materials, allowing the extraction of chemical and physical information of our environment. The availability of such a hyperspectral imager, that will operate mainly in the Mediterranean area, at the present represents a unique opportunity for those who are involved in environmental studies and land-management to collect systematically large-scale and high spectral-spatial resolution data of this part of the world. Nevertheless, MIVIS deployments will touch other parts of the world, where a major interest from the international scientific community is present
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