698 research outputs found
Nitric Acid Particles in Cold Thick Ice Clouds Observed at Global Scale: Link with Lightning, Temperature, and Upper Tropospheric Water Vapor
Signatures of nitric acid particles (NAP) in cold thick ice clouds have been derived from satellite observations. Most NAP are detected in the Tropics (9 to 20% of clouds with T less than 202.5 K). Higher occurrences were found in the rare mid-latitudes very cold clouds. NAP occurrence increases as cloud temperature decreases and NAP are more numerous in January than July. Comparisons of NAP and lightning distributions show that lightning is the main source of the NOx, which forms NAP in cold clouds. Qualitative comparisons of NAP with upper tropospheric humidity distributions suggest that NAP play a role in the dehydration of the upper troposphere when the tropopause is colder than 195K
Shortwave radiative forcing and efficiency of key aerosol types using AERONET data
The shortwave radiative forcing (&Delta;<i>F</i>) and the radiative forcing efficiency (&Delta;<i>F</i><sup>eff</sup>) of natural and anthropogenic aerosols have been analyzed using estimates of radiation both at the Top (TOA) and at the Bottom Of Atmosphere (BOA) modeled based on AERONET aerosol retrievals. Six main types of atmospheric aerosols have been compared (desert mineral dust, biomass burning, urban-industrial, continental background, oceanic and free troposphere) in similar observational conditions (i.e., for solar zenith angles between 55&deg; and 65&deg;) in order to compare the nearly same solar geometry. The instantaneous &Delta;<i>F</i> averages obtained vary from â122 ± 37 Wm<sup>â2</sup> (aerosol optical depth, AOD, at 0.55 ÎŒm, 0.85 ± 0.45) at the BOA for the mixture of desert mineral dust and biomass burning aerosols in West Africa and â42 ± 22 Wm<sup>â2</sup> (AOD = 0.9 ± 0.5) at the TOA for the pure mineral dust also in this region up to â6 ± 3 Wm<sup>â2</sup> and â4 ± 2 Wm<sup>â2</sup> (AOD = 0.03 ± 0.02) at the BOA and the TOA, respectively, for free troposphere conditions. This last result may be taken as reference on a global scale. Furthermore, we observe that the more absorbing aerosols are overall more efficient at the BOA in contrast to at the TOA, where they backscatter less solar energy into the space. The analysis of the radiative balance at the TOA shows that, together with the amount of aerosols and their absorptive capacity, it is essential to consider the surface albedo of the region on which they are. Thus, we document that in regions with high surface reflectivity (deserts and snow conditions) atmospheric aerosols lead to a warming of the Earth-atmosphere system
Multi-resolution image analysis for vehicle detection
Proceeding of: Second Iberian Conference, IbPRIA 2005, Estoril, Portugal, June 7-9, 2005Computer Vision can provide a great deal of assistance to Intelligent Vehicles. In this paper an Advanced Driver Assistance Systems for Vehicle Detection is presented. A geometric model of the vehicle is defined where its energy function includes information of the shape and symmetry of the vehicle and the shadow it produces. A genetic algorithm finds the optimum parameter values. As the algorithm receives information from a road detection module some geometric restrictions can be applied. A multi-resolution approach is used to speed up the algorithm and work in realtime. Examples of real images are shown to validate the algorithm.Publicad
Comparison of CALIPSO-Like, LaRC, and MODIS Retrievals of Ice Cloud Properties over SIRTA in France and Florida during CRYSTAL-FACE
This study compares cirrus particle effective radius retrieved by a CALIPSO-like method with two similar methods using MODIS, MODI Airborne Simulator (MAS), and GOES imagery. The CALIPSO-like method uses lidar measurements coupled with the split-window technique that uses the infrared spectral information contained at the 8.65-micrometer, 11.15-micrometer and 12.05-micrometer bands to infer the microphysical properties of cirrus clouds. The two other methods, sing passive remote sensing at visible and infrared wavelengths, are the operational MODIS cloud products (referred to by its archival product identifier MOD06 for MODIS Terra) and MODIS retrievals performed by the CERES team at LaRC (Langley Research Center) in support of CERES algorithms; the two algorithms will be referred to as MOD06- and LaRC-method, respectively. The three techniques are compared at two different latitudes: (i) the mid-latitude ice clouds study uses 18 days of observations at the Palaiseau ground-based site in France (SIRTA: Site Instrumental de Recherche par Teledetection Atmospherique) including a ground-based 532 nm lidar and the Moderate Resolution Imaging Spectrometer (MODIS) overpasses on the Terra Platform, (ii) the tropical ice clouds study uses 14 different flight legs of observations collected in Florida, during the intensive field experiment CRYSTAL-FACE (Cirrus Regional Study of Tropical Anvils and cirrus Layers-Florida Area Cirrus Experiment), including the airborne Cloud Physics Lidar (CPL) and the MAS. The comparison of the three methods gives consistent results for the particle effective radius and the optical thickness, but discrepancies in cloud detection and altitudes. The study confirms the value of an active remote-sensing method (CALIPSO-like) for the study of sub-visible ice clouds, in both mid-latitudes and tropics. Nevertheless, this method is not reliable in optically very thick tropical ice clouds
Synergistic use of Lagrangian dispersion and radiative transfer modelling with satellite and surface remote sensing measurements for the investigation of volcanic plumes: the Mount Etna eruption of 25â27 October 2013
Abstract. In this paper we combine SO2 and ash plume dispersion modelling with satellite and surface remote sensing observations to study the regional influence of a relatively weak volcanic eruption from Mount Etna on the optical and micro-physical properties of Mediterranean aerosols. We analyse the Mount Etna eruption episode of 25â27 October 2013. The evolution of the plume along the trajectory is investigated by means of the FLEXible PARTicle Lagrangian dispersion (FLEXPART) model. The satellite data set includes true colour images, retrieved values of volcanic SO2 and ash, estimates of SO2 and ash emission rates derived from MODIS (MODerate resolution Imaging Spectroradiometer) observations and estimates of cloud top pressure from SEVIRI (Spinning Enhanced Visible and InfraRed Imager). Surface remote sensing measurements of aerosol and SO2 made at the ENEA Station for Climate Observations (35.52°âŻN, 12.63°âŻE; 50âŻmâŻa.s.l.) on the island of Lampedusa are used in the analysis. The combination of these different data sets suggests that SO2 and ash, despite the initial injection at about 7.0âŻkm altitude, reached altitudes around 10â12âŻkm and influenced the column average aerosol particle size distribution at a distance of more than 350âŻkm downwind. This study indicates that even a relatively weak volcanic eruption may produce an observable effect on the aerosol properties at the regional scale. The impact of secondary sulfate particles on the aerosol size distribution at Lampedusa is discussed and estimates of the clear-sky direct aerosol radiative forcing are derived. Daily shortwave radiative forcing efficiencies, i.e. radiative forcing per unit AOD (aerosol optical depth), are calculated with the LibRadtran model. They are estimated between â39 and â48âŻWâŻmâ2âŻAODâ1 at the top of the atmosphere and between â66 and â49âŻWâŻmâ2âŻAODâ1 at the surface, with the variability in the estimates mainly depending on the aerosol single scattering albedo. These results suggest that sulfate particles played a large role in the transported plume composition and radiative forcing, while the contribution by ash particles was small in the volcanic plume arriving at Lampedusa during this event
3.5 The homing flight ring test: method for the assessment of sublethal doses of plant protection products on the honey bee in field conditions
International audienc
Inhibiting the inflammasome with MCC950 counteracts muscle pyroptosis and improves Duchenne muscular dystrophy
Background: Duchenne muscular dystrophy (DMD) is the most common inherited human myopathy. Typically, the secondary process involving severe inflammation and necrosis exacerbate disease progression. Previously, we reported that the NLRP3 inflammasome complex plays a crucial role in this disorder. Moreover, pyroptosis, a form of programmed necrotic cell death, is triggered by NLRP3 via gasdermin D (GSDMD). So far, pyroptosis has never been described either in healthy muscle or in dystrophic muscle. The aim of this study was to unravel the role of NLRP3 inflammasome in DMD and explore a potentially promising treatment with MCC950 that selectively inhibits NLRP3.
Methods: Fourâweekâold mdx mice (n=6 per group) were orally treated for 2 months with MCC950 (mdxâT), a highly potent, specific, small-molecule inhibitor of NLRP3, and compared with untreated (mdx) and wild-type (WT) mice. In vivo functional tests were carried out to measure the global force and endurance of mice. Ex vivo biochemical and molecular analyses were performed to evaluate the pathophysiology of the skeletal muscle. Finally, in vitro tests were conducted on primary cultures of DMD human myotubes.
Results: After MCC950 treatment, mdx mice exhibited a significant reduction of inflammation, macrophage infiltration and oxidative stress (-20 to -65%, P<0.05 vs untreated mdx). MdxâT mice displayed considerably less myonecrosis (-54%, P<0.05 vs mdx) and fibrosis (-75%, P<0.01 vs mdx). Moreover, a more mature myofibre phenotype, characterized by larger-sized fibres and higher expression of mature myosin heavy chains 1 and 7 was observed. Mdx-T also exhibited enhanced force and resistance to fatigue (+20 to 60%, P<0.05 or less). These beneficial effects resulted from MCC950 inhibition of both active caspase-1 (-46%, P=0.075) and cleaved gasdermin D (N-GSDMD) (-42% in medium-sized-fibres, P<0.001). Finally, the anti-inflammatory action and the anti-pyroptotic effect of MCC950 were also recapitulated in DMD human myotubes.
Conclusion: Specific inhibition of the NLRP3 inflammasome can significantly attenuate the dystrophic phenotype. A novel finding of this study is the overactivation of GSDMD, which is hampered by MCC950. This ultimately leads to less inflammation and pyroptosis and to a better muscle maturation and function. Targeting NLRP3 might lead to an effective therapeutic approach for a better management of DMD.Fund for Scientific Research de BĂ©lgica (FNRS)-PDR/T.0026.2
Detection violent behaviors: A survey
Violence detection behavior is a particular problem regarding the great problem action recognition. In recent years, the detection and recognition of violence has been studied for several applications, namely in surveillance. In this paper, we conducted a recent systematic review of the literature on this subject, covering a selection of various researched papers. The selected works were classified into three main approaches for violence detection: video, audio, and multimodal audio and video. Our analysis provides a roadmap to guide future research to design automatic violence detection systems. Techniques related to the extraction and description of resources to represent behavior are also reviewed. Classification methods and structures for behavior modelling are also provided.European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project n â 039334; Funding Reference: POCI-01-0247-FEDER-039334].
This work has been supported by national funds through FCT â Fundação para a CiĂȘncia e Tecnologia through project UIDB/04728/202
Effects of mixing state on optical and radiative properties of black carbon in the European Arctic
Atmospheric aging promotes internal mixing of black carbon
(BC), leading to an enhancement of light absorption and radiative forcing.
The relationship between BC mixing state and consequent absorption
enhancement was never estimated for BC found in the
Arctic region. In the present work, we
aim to quantify the absorption enhancement and its impact on radiative
forcing as a function of microphysical properties and mixing state of BC
observed in situ at the Zeppelin Arctic station (78° N) in the
spring of 2012 during the CLIMSLIP (Climate impacts of short-lived pollutants
in the polar region) project.Single-particle soot photometer (SP2) measurements showed a mean mass
concentration of refractory black carbon (rBC) of 39 ng mâ3, while the
rBC mass size distribution was of lognormal shape, peaking at an rBC mass-equivalent diameter (DrBC) of around 240 nm. On average, the
number fraction of particles containing a BC core with
DrBC>80 nm was less than 5 % in the size range (overall
optical particle diameter) from 150 to 500 nm. The BC cores were internally
mixed with other particulate matter. The median coating thickness of BC cores
with 220 nm < DrBC<â260 nm was 52 nm, resulting
in a coreâshell diameter ratio of 1.4, assuming a coated sphere morphology.
Combining the aerosol absorption coefficient observed with an Aethalometer
and the rBC mass concentration from the SP2, a mass absorption cross section
(MAC) of 9.8 m2 gâ1 was inferred at a wavelength of 550 nm.
Consistent with direct observation, a similar MAC value (8.4 m2 gâ1
at 550 nm) was obtained indirectly by using Mie theory and assuming a
coated-sphere morphology with the BC mixing state constrained from the SP2
measurements. According to these calculations, the lensing effect is
estimated to cause a 54 % enhancement of the MAC compared to that of bare
BC particles with equal BC core size distribution. Finally, the ARTDECO
radiative transfer model was used to estimate the sensitivity of the
radiative balance to changes in light absorption by BC as a result of a varying
degree of internal mixing at constant total BC mass. The clear-sky noontime
aerosol radiative forcing over a surface with an assumed wavelength-dependent
albedo of 0.76â0.89 decreased, when ignoring the absorption enhancement, by
â0.12 W mâ2 compared to the base case scenario, which was constrained
with mean observed aerosol properties for the Zeppelin site in Arctic spring.
The exact magnitude of this forcing difference scales with environmental
conditions such as the aerosol optical depth, solar zenith angle and surface
albedo. Nevertheless, our investigation suggests that the absorption
enhancement due to internal mixing of BC, which is a systematic effect,
should be considered for quantifying the aerosol radiative forcing in the
Arctic region.</p
Codi-strat - an interdisciplinary network geared towards sustainable management of chronic and infective diseases
A collaborative effort of clinicians, infectologists, molecular biologists, pharmacologists,
veterinarians, bioinformaticians, management and education specialists is united in order to
develop novel strategies of detecting early stages of chronic and infective diseases, their
prevention and therapy. CODI-STRAT integrates 15 centers conducting leadingâedge
research of chronic inflammatory/infective diseases from seven European (five
Mediterranean) countries and the USA, with specific aims to: i) establish long-standing
partner center cross-disciplinary collaborations for clinical studies and research, ii) provide
young investigators with broad and content-driven training and employability and iii)
promote scientists up-skilled in genomics, transcriptomics, tissue expression, human
serological and genetic studies, bioinformatics, chip technology, cell cultures and animal
models, all directed toward clinical translation and chronic/infective disease management.
This manuscript outlines the goals, partner roles and development of CODI-STRAT and its
programme.peer-reviewe
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