49 research outputs found
Self-gravitating fundamental strings and black-holes
The configuration of typical highly excited (M >> M_s ~ (alpha')^{-1/2})
string states is considered as the string coupling g is adiabatically
increased. The size distribution of very massive single string states is
studied and the mass shift, due to long-range gravitational, dilatonic and
axionic attraction, is estimated. By combining the two effects, in any number
of spatial dimensions d, the most probable size of a string state becomes of
order l_s = sqrt{2 alpha'} when g^2 M / M_s ~ 1. Depending on the dimension d,
the transition between a random-walk-size string state (for low g) and a
compact (~ l_s) string state (when g^2 M / M_s ~ 1) can be very gradual (d=3),
fast but continuous (d=4), or discontinuous (d > 4). Those compact string
states look like nuggets of an ultradense state of string matter, with energy
density rho ~ g^{-2} M_s^{d+1}. Our results extend and clarify previous work by
Susskind, and by Horowitz and Polchinski, on the correspondence between
self-gravitating string states and black holes.Comment: 28 pages, Revtex, minor misprints and references correcte
BCL-XL overexpression promotes tumor progression-associated properties article
By using human melanoma and glioblastoma cell lines and their derivative BCL-XL overexpressing clones, we investigated the role of BCL-XL in aggressive features of these two tumor histotypes. We found that in both models, BCL-XL overexpression increased in vitro cell migration and invasion and facilitated tumor cells to form de novo vasculogenic structures. Furthermore, BCL-XL overexpressing cells exhibited higher tumors sphere formation capacity and expressed higher levels of some stem cell markers, supporting the concept that BCL-XL plays essential roles in the maintenance of cancer stem cell phenotype. BCL-XL expression reduction by siRNA, the exposure to a BCL-XL-specific inhibitor and the use of a panel of human melanoma cell lines corroborated the evidence that BCL-XL regulates tumor progression-associated properties. Finally, the vascular markers and the vasculogenic mimicry were up-regulated in the BCL-XL overexpressing xenografts derived from both tumor histotypes. In conclusion, our work brings further support to the understanding of the malignant actions of BCL-XL and, in particular, to the concept that BCL-XL promotes stemness and contributes to the aggressiveness of both melanoma and glioblastoma
At the intersection of cultural and natural heritage: Distribution and conservation of the type localities of Italian endemic vascular plants
We conducted a GIS spatial analysis with the aim of providing the first quantitative large-scale overview of the distribution patterns of 1536 type localities (loci classici) of 1216 Italian endemic vascular plants and their relationship with a set of descriptive variables. Whereas some variables were used to model the presence-absence distribution patterns of the type localities for the whole set of endemics as well as for the subset of narrow endemics, others (e.g., presence inside or outside protected areas and Italian Important Plant Areas) were considered with the purpose of assessing potential assets or risks for conservation.
The largest number of type localities was found within the Mediterranean biogeographic region (1134), followed by the Alpine region (306) and Continental region (96). A total of 670 locations are located on islands, whereas 866 are located on the Italian mainland (139 and 124 in the case of narrow endemics, respectively). A large number of type localities are located in mountainous areas and along the coastline, which can be seen as a potential risk for conservation. On the contrary, we detected a positive correlation with the distance from roads, which might be considered to be an asset. Importantly, 1030 type localities fall inside protected areas, whereas 506 localities fall outside protected areas, with 259 of these unprotected localities on islands.
We propose considering the results of the analysis of the distribution of type localities of Italian endemics to be a strategic tool for conservation planning and resource management. Application of plant micro-reserves and integration of diverse legislation tools are suggested to strengthen efforts and increase conservation success
Notulae to the Italian alien vascular flora 6
In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions of taxa in the genera Acalypha, Acer, Canna, Cardamine, Cedrus, Chlorophytum, Citrus, Cyperus, Epilobium, Eucalyptus, Euphorbia, Gamochaeta, Hesperocyparis, Heteranthera, Lemna, Ligustrum, Lycium, Nassella, Nothoscordum, Oenothera, Osteospermum, Paspalum, Pontederia, Romulea, Rudbeckia, Salvia, Sesbania, Setaria, Sicyos, Styphnolobium, Symphyotrichum, and Tradescantia. Nomenclature and distribution updates, published elsewhere, and corrigenda are provided as supplementary material
Notulae to the Italian native vascular flora: 1
In this contribution, new data concerning the Italian distribution of native vascular flora are presented. It includes new records, exclusions, and confirmations pertaining to the Italian administrative regions for taxa in the genera Arundo, Bromopsis, Cistus, Crocus, Festuca, Galeopsis, Genista, Lamium, Leucanthemum, Nerium, Orobanche, Peucedanum, Pilosella, Polycnemum, Stipa and Viola
Safe Integration of Fully Automated Road Transport Systems in Urban Environments: Basis for Missing Legal Framework
International audienceAutomated Road Transport Systems (ARTS) are transport systems based on the use of fully automated road vehicles controlled by a centralized fleet and infrastructure management system. ARTS are aimed (at least at the beginning) at supplementing mass transit in the last mile and are commercially available today. However, their deployment is limited at the moment, to protected or special roads, while in urban areas, where these systems can be most beneficial, they cannot be implemented due to the absence of an adapted legal framework. The CityMobil2 project, financed by the European Commission, aims at removing (amongst others) the legal barriers that prevent the deployment of Automated Road Transport Systems in urban areas, by developing a specific legal framework. Previous experiences based on risk assessment and Failure Mode, Effect and Criticality Analysis (FMECA) have demonstrated being acceptable to the National authorities. On this basis, the CityMobil2 project has started developing a methodology for the certification of fully Automated Road Transport Systems, aimed at guaranteeing an adequate level of safety. The certification framework has been developed at theoretical level, but during the next phases of the CityMobil2 project, it will be tested in real life conditions during the ARTS demonstrations that will be organized in several cities of Europe, in order to make of this methodology a major reference for a future legal framework