1,148 research outputs found
Path-tracing Monte Carlo Library for 3D Radiative Transfer in Highly Resolved Cloudy Atmospheres
Interactions between clouds and radiation are at the root of many
difficulties in numerically predicting future weather and climate and in
retrieving the state of the atmosphere from remote sensing observations. The
large range of issues related to these interactions, and in particular to
three-dimensional interactions, motivated the development of accurate radiative
tools able to compute all types of radiative metrics, from monochromatic, local
and directional observables, to integrated energetic quantities. In the
continuity of this community effort, we propose here an open-source library for
general use in Monte Carlo algorithms. This library is devoted to the
acceleration of path-tracing in complex data, typically high-resolution
large-domain grounds and clouds. The main algorithmic advances embedded in the
library are those related to the construction and traversal of hierarchical
grids accelerating the tracing of paths through heterogeneous fields in
null-collision (maximum cross-section) algorithms. We show that with these
hierarchical grids, the computing time is only weakly sensitivive to the
refinement of the volumetric data. The library is tested with a rendering
algorithm that produces synthetic images of cloud radiances. Two other examples
are given as illustrations, that are respectively used to analyse the
transmission of solar radiation under a cloud together with its sensitivity to
an optical parameter, and to assess a parametrization of 3D radiative effects
of clouds.Comment: Submitted to JAMES, revised and submitted again (this is v2
Les effets de la règlementation de la culture : l’exemple de la production de vin en Calabre
Based on ethnographical fieldwork conducted in
Calabria, Italy, this paper studies the effects of regulations aimed to protect a cultural
practice, the production of wine, over a period of forty years. More precisely, it seeks to
demonstrate how state regulation of a cultural practice transforms the way the people view and
relate to the cultural process in question. Some aspects of the cultural heritage tend to
become more rigid, while other aspects continue to evolve.L’objectif de cet article consiste à analyser les
effets sur une pĂ©riode de plus de quarante ans de la mise en place de règlementations visant Ă
protĂ©ger une pratique culturelle, la production de vin. Plus spĂ©cifiquement, il cherche Ă
démontrer comment l’inscription d’une pratique culturelle dans un règlement oriente au fil du
temps les manières dont les personnes en viennent à se représenter l’activité culturelle en
question. Les dimensions explicites inscrites dans les règlements se rigidifient et ne doivent
plus évoluer, tandis que d’autres, non inscrites, peuvent continuer à évoluer et se
transformer. Cet article s’appuie sur une recherche ethnographique effectuée en Calabre,
Italie
Le développement de l'industrie vitivinicole et les représentations du vin à Cirò en Calabre : une anthropologie du particulier
Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal
Matériau composite à base de matière naturelle lignocellulosique
L'invention concerne un matériau composite à base de particules d'une matière naturelle lignocellulosique, notamment de bois. Ces particules sont dispersées dans une matrice d'un polymère thermoplastique choisi parmi les polyamides et les copolymères à blocs comprenant au moins un bloc polyamide. Un procédé de préparation de ce matériau composite comprend le mélange desdites particules et dudit polymère thermoplastique et la mise en forme de ce mélange
Diets containing shrimp protein hydrolysates provided protection to European sea bass (Dicentrarchus labrax) affected by a Vibrio pelagius natural infection outbreak
This study was conducted to investigate the effects of the dietary supplementation of shrimp protein hydrolysate (SPH) on somatic growth performance, innate immune response in juvenile European sea bass (Dicentrarchus labrax) and their differential cumulative mortality when affected by a Vibrio pelagius natural infection outbreak. A diet containing 20% fish meal (FM) was used as a control, whereas three other diets differing in the level of FM inclusion (75 and 25% FM replacement by plant protein sources) and the inclusion of the additive (5% FM, 5% FM + 5% SPH and 15% FM + 5% SPH) were tested. After 110 days, there were no statistically significant differences in somatic growth parameters nor proximate composition in fish fed different experimental diets (P > 0.05), while the humoral non-specific immune responses (lysozyme, bacteriolytic and complement activities) were significantly enhanced by the inclusion of SPH in diets (P < 0.05). Additionally, an outbreak of the pathogenic bacteria V. pelagius, a bacterial species previously described as producer of the virulence factor hemolysin, occurred in all experimental tanks (4 replicates per diet) due to crowding and repeated handling stress for fish sorting. Survival rates among different experimental groups ten days after the bacterial epizootic differed depending on the diets, with groups containing SPH showing the best results (P < 0.05). In particular, fish fed the 15% FM + 5% SPH diet showed the highest survival rate (96.4 ± 5.0%), followed by those fed the 5% FM5 + 5% SPH5 (61.8 ± 16.3%). In contrast, survival rates in fish fed diets deprived of the additive (20% FM and 5% FM5 diets) were the lowest ones (32.0 ± 6.7% and 38.2 ± 13.5%, respectively). The present study showed that SPH can be incorporated in aquafeeds with high levels of FM substitution by PP sources without detrimental impact on the somatic growth performance of fish. In addition, the non-specific humoral immunity in seabass and their survival when affected by an epizootic outbreak of V. pelagius were positively affected, which showed the immunomodulatory benefits of shrimp protein hydrolysate to promote health and prevent diseases in fish.info:eu-repo/semantics/acceptedVersio
COMBINED CONDUCTIVE-RADIATIVE HEAT TRANSFER ANALYSIS IN COMPLEX GEOMETRY USING THE MONTE CARLO METHOD
Deterministic methods are commonly used to solve the heat balance equation in three-dimensional (3D) geometries. This article presents a preliminary study to the use of a stochastic method for the computation of the temperature in complex 3D geometries where the combined conductive and radiative heat transfers are coupled in the porous solid phase. The Monte Carlo algorithm and its results are validated by a comparison with the results obtained with a conventional finite-volume method
Net-Exchange parameterization of infrared radiative transfers in Venus' atmosphere
International audienceThermal radiation within Venus atmosphere is analyzed in close details. Prominent features are identified, which are then used to design a parameterization (a highly simplified and yet accurate enough model) to be used in General Circulation Models. The analysis is based on a net exchange formulation, using a set of gaseous and cloud optical data chosen among available referenced data. The accuracy of the proposed parameterization methodology is controlled against Monte Carlo simulations, assuming that the optical data are exact. Then, the accuracy level corresponding to our present optical data choice is discussed by comparison with available observations, concentrating on the most unknown aspects of Venus thermal radiation, namely the deep atmosphere opacity and the cloud composition and structure
Development of coronary dysfunction in adult progeny after maternal engineered nanomaterial inhalation during gestation
Maternal exposure to environmental contaminants during pregnancy can profoundly influence the risk of developing cardiovascular disease in adult offspring. Our previous studies have demonstrated impaired cardiovascular health, microvascular reactivity, and cardiac function in fetal and young adult progeny after maternal inhalation of nano-sized titanium dioxide (nano-TiO2) aerosols during gestation. The present study was designed to evaluate the development of cardiovascular and metabolic diseases later in adulthood. Pregnant Sprague-Dawley rats were exposed to nano-TiO2 aerosols (similar to 10 mg/m(3), 134 nm median diameter) for 4 h per day, 5 days per week, beginning on gestational day (GD) 4 and ending on GD 19. Progeny were delivered in-house. Body weight was recorded weekly after birth. After 47 weeks, the body weight of exposed progeny was 9.4% greater compared with controls. Heart weight, mean arterial pressure, and plasma biomarkers of inflammation, dyslipidemia, and glycemic control were recorded at 3, 9 and 12 months of age, with no significant adaptations. While no clinical risk factors (i.e., hypertension, dyslipidemia, or systemic inflammation) emerged pertaining to the development of cardiovascular disease, we identified impaired endothelium-dependent and -independent arteriolar dysfunction and cardiac morphological alterations consistent with myocardial inflammation, degeneration, and necrosis in exposed progeny at 12 months. In conclusion, maternal inhalation of nano-TiO2 aerosols during gestation may promote the development of coronary disease in adult offspring
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