1,825 research outputs found
Memories of a botanical trip to Mallorca in 1952
Abstract not availabl
Impact of information technology on future floras
Some important facilities offered by the information technology to innovate the development of traditional floras are illustrated and discussed. These include: random access interactive tools for the identification of species, low cost, easy updating, virtually unlimited space for high resolution images and texts, on-line utilities, strong synergy between authors and users. It is argued
that the combination of printed books with integrated digital utilities and data-sources is the most desirable structure for future floras
MIVIS image geocoding experience on merging position attitude system data and public domain GPS stream (ASI-GeoDAF)
The use of airborne scanners involves geo-referencing problems, which are difficult because of the need to know
the exact platform position and attitude for each scan line. The errors of the onboard navigation system are normally
corrected using ground control point on the image. This post-processing correction procedure is too long
in case of multiple flight campaigns, and besides it implies the need to have available 1:10000 orthophotoimages
or maps in digital format. To optimize the above procedure a new method to correct MIVIS navigational
data in the post-processing phase has been implemented. The procedure takes into consideration the GPS stream
in Rinex format of common knowledge and findable on the web, acquired at the ground stations of the Geodetic
Data Archiving Facilities provided by ASI. The application of this correction entails the assumption that the
environmental variables affecting both onboard and geodetic GPS equally affect the position measurements. The
airborne data correction was carried out merging the two data sets (onboard and ground station GPS) to achieve
a more precise aircraft trajectory. The present study compares the geo-coded images obtained by means of the
two post-processing methods
Cascading effects of canopy mortality drive long-term changes in understorey diversity in temperate old-growth forests of Europe
Questions: We investigated the influence of protracted mortality of a dominant canopy tree (Abies alba) on long-term understorey dynamics. We ask (a) how tree regeneration and understorey species diversity and composition changed over 32 years; and (b) whether the observed changes were mainly driven by mortality of A. alba.
Location: Three old-growth forest reserves dominated by A. alba and Fagus sylvatica in the Dinaric Mountains of Slovenia.
Method: Tree layer and understorey regeneration and herbs were surveyed in 147 plots across the three forest reserves in 1983 and 2015. Soils were also sampled in 2015. The study period coincides with a protracted period of increased A. alba mortality in the canopy layer associated with anthropogenic emissions.
Results: Between 1983 and 2015, the decline in canopy layer A. alba caused a recruitment pulse of F. sylvatica regeneration to the subcanopy tree layer across the three reserves. These changes were accompanied by a significant decline in plot level herb species richness. A model-based analysis of beta-diversity revealed significant community convergence during the study period, mainly caused by the loss of rare species. Ellenberg values indicate that these changes were mainly driven by loss of understorey light, while an increase in soil pH may have played a role also.
Conclusions: This observational study suggests that the long-term decline of A. alba resulted in a cascade of processes - widespread F. sylvatica recruitment that impeded penetration of light to the forest floor, and possibly a change in soil conditions due to the decline of coniferous litter. These changes caused a significant loss of herb diversity and homogenization of the understorey community across the three sites. This study sheds light on the potential cascading consequences triggered by episodes of increased tree mortality resulting from global-change-type drivers
Nutrients and pathways that regulate health span and life span
Both life span and health span are influenced by genetic, environmental and lifestyle factors. With the genetic influence on human life span estimated to be about 20\u201325%, epigenetic changes play an important role in modulating individual health status and aging. Thus, a main part of life expectance and healthy aging is determined by dietary habits and nutritional factors. Excessive or restricted food consumption have direct effects on health status. Moreover, some dietary interventions including a reduced intake of dietary calories without malnutrition, or a restriction of specific dietary component may promote health benefits and decrease the incidence of aging-related comorbidities, thus representing intriguing potential approaches to improve healthy aging. However, the relationship between nutrition, health and aging is still not fully understood as well as the mechanisms by which nutrients and nutritional status may affect health span and longevity in model organisms. The broad effect of different nutritional conditions on health span and longevity occurs through multiple mechanisms that involve evolutionary conserved nutrient-sensing pathways in tissues and organs. These pathways interacting each other include the evolutionary conserved key regulators mammalian target of rapamycin, AMP-activated protein kinase, insulin/insulin-like growth factor 1 pathway and sirtuins. In this review we provide a summary of the main molecular mechanisms by which different nutritional conditions, i.e., specific nutrient abundance or restriction, may affect health span and life span
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
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
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