An analytical model based on radiative heating for the determination of safety distances for wildland fires

International audienceThe radiative heat transfer is often the main thermal impact of a wildfire on people fighting the fire or on structures. Thus, the estimation of the radiation coming from the fire font and hitting a target is of primary importance for forest and urban managers. A new flame model based on the solid flame assumption is developed by considering a finite fire front width. The realistic description of finite fire front widths allows proposing a new criterion for the estimation of the radiative impact of the fire, which is based on the ratio fire front width/ flame length, opposed to the classical approach of considering only the flame length. The new model needs to be solved numerically so an analytical approximation is proposed to obtain a simple and useful formulation of the acceptable safety distance. A sensivity analysis is conducted on the different physical and geometrical parameters used to define the flame front. This analysis shows that the flame temperature is the most sensitive parameter. The results of the analytical model are compared with the numerical solution of the flame model and previous approaches based only on flame length. The results show that the analytical model is a good approximation of the numerical approach and displays realistic estimations of the acceptable safety distance for different fire front characteristics

NEW RECORDS OF NATIVE AND ALIEN VASCULAR PLANTS FROM ABRUZZO, LAZIO AND MOLISE NATIONAL PARK (ITALY) – AND ADDITIONS TO THE FLORA OF ABRUZZO AND MOLISE ADMINISTRATIVE REGIONS

The Abruzzo, Lazio and Molise National Park, a flagship conservation area in Italy, is a hotspot of floristic diversity and a crossroad for plant biogeography. In this work, as a result of recent field studies in the Park and herbarium revisions, we report 10 taxa new or confirmed for the Abruzzo administrative region, and 3 for the Molise administrative region. Moreover, 47 taxa of vascular plants (41 native and 6 alien taxa) that are new or confirmed for the flora of the Park are reported. Five taxa are excluded from the flora of the Park

NEW RECORDS OF NATIVE AND ALIEN VASCULAR PLANTS FROM ABRUZZO, LAZIO AND MOLISE NATIONAL PARK (ITALY) - AND ADDITIONS TO THE FLORA OF ABRUZZO AND MOLISE ADMINISTRATIVE REGIONS

The Abruzzo, Lazio and Molise National Park, a flagship conservation area in Italy, is a hotspot of floristic diversity and a crossroad for plant biogeography. In this work, as a result of recent field studies in the Park and herbarium revisions, we report 10 taxa new or confirmed for the Abruzzo administrative region, and 3 for the Molise administrative region. Moreover. 47 taxa of vascular plants (41 native and 6 alien taxa) that are new or confirmed for the flora of the Park are reported. Five taxa are excluded from the flora of the Park

Nanodot-Cavity Electrodynamics and Photon Entanglement

Quantum electrodynamics of excitons in a cavity is shown to be relevant to quantum operations. We present a theory of an integrable solid-state quantum controlled-phase gate for generating entanglement of two photons using a coupled nanodot-microcavity-fiber structure. A conditional phase shift of $O(\pi/10)$ is calculated to be the consequence of the giant optical nonlinearity keyed by the excitons in the cavities. Structural design and active control, such as electromagnetic induced transparency and pulse shaping, optimize the quantum efficiency of the gate operation.Comment: 4 pages 3 figure

Acute exacerbation of idiopathic pulmonary fibrosis: report of a series

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Drag in a resonantly driven polariton fluid

We study the linear response of a coherently driven polariton fluid in the pump-only configuration scattering against a point-like defect and evaluate analytically the drag force exerted by the fluid on the defect. When the system is excited near the bottom of the lower polariton dispersion, the sign of the interaction-renormalised pump detuning classifies the collective excitation spectra into three different categories (Ciuti and Carusotto 2005 Phys. Status Solidi b 242 2224): linear for zero, diffusive-like for positive and gapped for negative detuning. We show that both cases of zero and positive detuning share a qualitatively similar crossover of the drag force from the subsonic to the supersonic regime as a function of the fluid velocity, with a critical velocity given by the speed of sound found for the linear regime. In contrast, for gapped spectra, we find that the critical velocity exceeds the speed of sound. In all cases, the residual drag force in the subcritical regime depends on the polariton lifetime only. Also, well below the critical velocity, the drag force varies linearly with the polariton lifetime, in agreement with previous work (Cancellieri et al 2010 Phys. Rev. B 82 224512), where the drag was determined numerically for a finite-size defect

Spin Textures of Polariton Condensates in a Tunable Microcavity with Strong Spin-Orbit Interaction

We report an extended family of spin textures in coexisting modes of zero-dimensional polariton condensates spatially confined in tunable open microcavity structures. The coupling between photon spin and angular momentum, which is enhanced in the open cavity structures, leads to new eigenstates of the polariton condensates carrying quantised spin vortices. Depending on the strength and anisotropy of the cavity confinement potential and the strength of the spin-orbit coupling, which can be tuned via the excitonic/photonic fractions, the condensate emissions exhibit either spin-vortex-like patterns or linear polarization, in good agreement with theoretical modelling

Contribution to the floristic knowledge of Lipari and Panarea Islands (Sicilia, Italy)

The inventory of the taxa collected in 2022 during the annual field trip of the Working Group for Floristics, Systematics and Evolution of the Italian Botanical Society is reported. The field trip was held from 19th to 22th April in the islands of Lipari and Panarea (Aeolian Islands, Sicilia). Overall, 1,664 herbarium specimens were deposited in public and private herbaria. The flora documented for the studied area amounts to 386 specific and subspecific taxa, belonging to 241 genera and 74 families. Centaurea aeolica, Helichrysum litoreum (Asteraceae), and Dianthus rupicola subsp. aeolicus (Caryophyllaceae) were the only three Italian endemics found in the study area, whereas 48 alien taxa were recorded. Dimorphotheca ecklonis (Asteraceae), Nassella tenuissima (Poaceae), Solanum torvum (Solanaceae), and Viola wittrockiana (Violaceae) are casual alien species new to Sicilia, whereas Oenothera odorata (Onagraceae) is a new naturalized alien species for the Italian vascular flora