de Freitas S.R.C.,Federal University of Paraná |
Ferreira V.G.,Federal University of Paraná |
Palmeiro A.S.,Federal University of Paraná |
de Carvalho J.L.B.,University of Itajai Valey |
da Silva L.F.,University of Itajai Valey
International Association of Geodesy Symposia | Year: 2010
The region contiguous to the Brazilian Vertical Datum (BVD) lacks of observations and data required for realizing its connection with other vertical networks in the world as required for a Global Vertical Reference System (GVRS). A consistent positional and gravity data base in the region is a fundamental condition for realizing the future Vertical Datum SIRGAS (Sistema de Referência Geocêntrico para as Américas) - DVSIRGAS (Drewes et al., Vertical Reference System, IAG Symposia Series, Springer, Berlin. vol. 124, pp. 297-301, 2002). In the BVD region, placed in the Imbituba harbor, South Brazil, several benchmarks (BM's) have been lost. In order to improve the distribution of data in this region, we conducted a study on the behavior of the system of three linked lagoons under influence of the ocean dynamics in the region. They cover about 20 × 30 km with a 140 km perimeter in the contiguous region of the BVD. The purpose was to use its mean level as an indicator of a natural equipotential surface close to the geoid (or quasi-geoid). A local geodetic network with about 200 points was established. In this network gravity and precise position with Global Positioning System (GPS) were observed. Some of these points are existing BM's connected to the BVD. Three tide gauges that recorded the heights of the water level in the lagoons over a period of approximately 3 months were also employed. In this lagoon system, it was possible to determine an approximate equipotential surface from the mean lagoon level (MLL). Then, we determined the shift between the geopotential in the BVD and the lagoon system. Estimations coming from a global geopotential model allowed determination of a provisional value for the Sea Surface Topography (SST) in the BVD. © Springer-Verlag Berlin Heidelberg 2010.
Valletta A.,University of Rome La Sapienza |
Santamaria A.R.,University of Rome La Sapienza |
Fabrini G.,University of Rome La Sapienza |
Tocci N.,University of Rome La Sapienza |
And 4 more authors.
Plant Biosystems | Year: 2015
Centaurea cineraria subsp. circae is an endemic plant with a distribution area limited to Circeo mountain (Lazio, Italy), whose population was estimated in a very low number of individuals. The aim of this work was to investigate ex situ conservation strategies such as achene collection and in vitro plant propagation, which will permit to carry out restoration programmes. The test carried out on the achenes demonstrated that only 5.5% of them were morphologically healthy. Seed germination tests showed that seeds do not display dormancy and that germination does not require pre-treatments. The higher germination rate (67.5%) was observed under a photoperiod of 12/12 h (light/dark) and temperature regime +20/+10°C. The in vitro studies demonstrated that micropropagation, acclimatization and the transfer outdoors of C. cineraria subsp. circae are not particularly difficult: 74% of shoot explants in a Murashige and Skoog (MS) medium added with 0.5 mg/l benzylaminopurine and 2 mg/l kinetin formed multiple shoots; 100% of shoots rooted in the MS medium added with 0.5 mg/l indole-3-butyric acid and over 90% survived the acclimatization phase. After been transferred outdoors, the totality of in vitro-propagated plants bloomed and appeared morphologically indistinguishable from wild plants. Preliminary chemical analyses showed a similar profile for in vitro-propagated and wild plants. © 2015 Società Botanica Italiana