Utilisation de séries temporelles d’images satellitales pour cartographier le dépérissement des boisements résineux du Sud Massif Central

La canicule de 2003 a provoqué dans le Sud Massif Central des dépérissements résineux brutaux et massifs. Après la crise est venu le temps de l’analyse, en évaluant d’abord l’étendue des impacts, ne serait-ce que pour organiser les reconstitutions à l’échelle régionale. La méthode de télédétection imaginée et mise en oeuvre avec succès est bien adaptée à ce type de phénomène, avec ceci d’original qu’elle intègre les coupes sanitaires d’urgence comme indicateur de l’intensité du dépérissement. Mais gardons-nous de généraliser, car de ce fait même elle ne se prêterait pas à l’évaluation d’autres types de dépérissement, plus diffus ou aux symptômes plus « subtils »

Detecting clear-cuts and decreases in forest vitality using MODIS NDVI time series

This paper examines the potential of MODIS-NDVI time series for detecting clear-cuts in a coniferous forest stand in the south of France. The proposed approach forms part of a survey monitoring the status of forest health and evaluating the forest decline phenomena observed over the last few decades. One of the prerequisites for this survey was that a rapid and easily reproducible method had to be developed that differentiates between forest clear-cuts and changes in forest health induced by environmental factors such as summer droughts. The proposed approach is based on analysis of the breakpoints detected within NDVI time series, using the "Break for Additive Seasonal and Trend" (BFAST) algorithm. To overcome difficulties detecting small areas on the study site, we chose a probabilistic approach based on the use of a conditional inference tree. For model calibration, clear-cut reference data were produced at MODIS resolution (250 m). According to the magnitude of the detected breakpoints, probability classes for the presence of clear-cuts were defined, from greater than 90% to less than 3% probability of a clear-cut. One of the advantages of the probabilistic model is that it allows end users to choose an acceptable level of uncertainty depending on the application. In addition, the use of BFAST allows events to be dated, thus making it possible to perform a retrospective analysis of decreases in forest vitality in the study area

Evaluation cartographique de la dynamique d'un paysage

Lors de la mise en place des Pares Naturels Régionaux, l'analyse de la dimensión paysagére tient xme place particuliére. Elle permet d'identifier les ensembles de territoires qui constituent des éléments caiactéristiques de l'intérét de ees Pares. Mais ees Pares ont souvent des superficies de plusieurs centaines de km2, et les méthodes de description des paysages qui sont employées doivent pouvoir opérer a des échelles intermédiaires (1:50 000). Les méthodes développées en géomatique (modele numérique de terrain, cartographie numérique, traitement des images satellitaires) offrent des perspectives intéressantes pour permettre de telles analyses. En particulier, elles permettent l'introduction d'une analyse multidimensionnelle de la qualiñcation des paysages

Sculpture moderne : la terre cuite française

Première série. Reproduction héliographique de l'oeuvre de / Joseph CheretCopia digital. España : Ministerio de Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201

Evaluating patient preference and satisfaction for human immunodeficiency virus therapy in France

Objectives The objectives were 1) to elicit relative preferences for attributes of antiretroviral therapies (ART) in people living with HIV (PLWH) and 2) to explore satisfaction and adherence with current ART. Patients and methods We conducted a multicenter cross-sectional study, consecutively enrolling PLWH receiving an ART. The quantitative part estimated the strength of preference for different attributes using an online discrete choice experiment (DCE). DCE data were analyzed using a mixed logit regression model. Qualitative data were collected through individual interviews. A preliminary coding framework was developed which was then further refined and applied during thematic analysis of factors influencing satisfaction and adherence. Results A total of 101 PLWH took part in the quantitative part and 31 in the qualitative part. Over 90% had an undetectable viral load. Quantitative data revealed a strong preference for a treatment with limited drug–drug interactions, diarrhea and long-term health problems (P<0.0001), and that did not need to be taken on an empty stomach (P<0.0001). Patients also preferred to avoid problems associated with treatment failure (P<0.0001) or one that left them with a higher viral load after the first weeks of treatment (P=0.044). Differences in CD4 cell count, and pills that must be taken with food were not significant drivers of treatment choice. The strength of these attributes was reflected in the qualitative data, highlighting the importance patients place on treatment efficacy, and also suggesting that some of these attributes may impact adherence. Many factors influencing adherence and satisfaction with treatment were identified, including pill size, worry about sexual transmission and impact on social life. Conclusion Most of the attributes included in this survey were important to participants when choosing an ART, in particular those related to quality of life, and these should be taken into account in order to optimize adherence and satisfaction

Maf links Neuregulin1 signaling to cholesterol synthesis in myelinating Schwann cells

Cholesterol is a major constituent of myelin membranes, which insulate axons and allow saltatory conduction. Therefore, Schwann cells, the myelinating glia of the peripheral nervous system, need to produce large amounts of cholesterol. Here, we define a crucial role of the transcription factor Maf in myelination and cholesterol biosynthesis and show that Maf acts downstream from Neuregulin1 (Nrg1). Maf expression is induced when Schwann cells begin myelination. Genetic ablation of Maf resulted in hypomyelination that resembled mice with defective Nrg1 signaling. Importantly, loss of Maf or Nrg1 signaling resulted in a down-regulation of the cholesterol synthesis program, and Maf directly binds to enhancers of cholesterol synthesis genes. Furthermore, we identified the molecular mechanisms by which Nrg1 signaling regulates Maf levels. Transcription of Maf depends on calmodulin-dependent kinases downstream from Nrg1, whereas Nrg1-MAPK signaling stabilizes Maf protein. Our results delineate a novel signaling cascade regulating cholesterol synthesis in myelinating Schwann cells

Comparison of metabolic abnormalities and clinical lipodystrophy 48 weeks after switching from HAART to Trizivir versus continued HAART: the Trizal study

PURPOSE: To analyze the evolution of clinical lipodystrophy (LD) and metabolic abnormalities in patients continuing to receive HAART versus patients switched to Trizivir (zidovudine, lamivudine, abacavir) after 48 weeks. METHOD: Patients treated with HAART >6 months with plasma HIV-1 RNA viral load (VL) <400 copies/mL and <50 copies/mL at screening were randomly assigned to continue HAART (103 patients) or to receive Trizivir (106 patients). Clinical LD was evaluated using a standardized patient questionnaire only at baseline, weeks 4 and 8, and then every 8 weeks until Week 48. Laboratory evaluation was performed every 4 weeks. RESULTS: The proportion of patients exhibiting >or=1 LD symptom at baseline was 40% in the Trizivir arm and 50% in HAART arm (difference not significant). After 48 weeks, the prevalence was 28% and 42% respectively (p =.03), and the median number of LD symptoms per patient was 2 in the Trizivir arm and 4 in the continued HAART arm (p =.016). Median decreases in cholesterol levels over the 48-week study period were greater in the Trizivir arm than in the continued HAART arm (-0.80 vs. -0.44 mmol/L; p lt.001). Median triglyceride levels decreased in the Trizivir arm but increased in the continued HAART arm (-0.17 and +0.01 mmol/L; p =.006). Suppression of VL was maintained in most patients with no differences between the two arms. CONCLUSION: A switch from "standard" HAART to Trizivir was associated with an improvement in clinical LD and blood lipid abnormalities after 48 weeks

Detecting clear-cuts and decreases in forest vitality using MODIS NDVI time series

This paper examines the potential of MODIS-NDVI time series for detecting clear-cuts in a coniferous forest stand in the south of France. The proposed approach forms part of a survey monitoring the status of forest health and evaluating the forest decline phenomena observed over the last few decades. One of the prerequisites for this survey was that a rapid and easily reproducible method had to be developed that differentiates between forest clear-cuts and changes in forest health induced by environmental factors such as summer droughts. The proposed approach is based on analysis of the breakpoints detected within NDVI time series, using the “Break for Additive Seasonal and Trend” (BFAST) algorithm. To overcome difficulties detecting small areas on the study site, we chose a probabilistic approach based on the use of a conditional inference tree. For model calibration, clear-cut reference data were produced at MODIS resolution (250 m). According to the magnitude of the detected breakpoints, probability classes for the presence of clear-cuts were defined, from greater than 90% to less than 3% probability of a clear-cut. One of the advantages of the probabilistic model is that it allows end users to choose an acceptable level of uncertainty depending on the application. In addition, the use of BFAST allows events to be dated, thus making it possible to perform a retrospective analysis of decreases in forest vitality in the study area

Photoactivated Refractive Index Anisotropy in Fluorescent Thiophene Derivatives

The optical control of anisotropy in materials is highly advantageous for many technological applications, including the real-time modulation of another light signal in photonic switches and sensors. Here, we introduce three thiophene derivatives with a donor-acceptor structure, which feature different positions of an electron-acceptor nitrile group, and both photoalignment and luminescence properties. Quantum chemical calculations highlight the presence of trans-forms stable at room temperature and metastable cis-isomers. Besides photoluminescence peaked at 440-460 nm and 0.4 ns lifetime, the three nonlinear optical chromophores exhibit photoinduced anisotropy of the refractive index closely depending on the specific molecular structure, with higher values of birefringence at lower driving signal being obtained for ortho substitution of the nitrile group. All-optical modulation of an external light beam at rates of hundreds of hertz is demonstrated in the fluorescent systems. This finding opens an interesting route to multispectral photonic switches embedded in the active layers of light-emitting devices

Thyroid hormones enhance mitochondrial function in human epidermis

Since it is unknown whether thyroid hormones (THs) regulate mitochondrial function in human epidermis, we treated organ-cultured human skin, or isolated cultured human epidermal keratinocytes, with triiodothyronine (100 pmol/L) or thyroxine (100 nmol/L). Both THs significantly increased protein expression of the mitochondrially encoded cytochrome C oxidase I (MTCO1), complex I activity, and the number of perinuclear mitochondria. Triiodothyronine also increased mitochondrial transcription factor A (TFAM) protein expression, and thyroxine stimulated complex II/IV activity. Increased mitochondrial function can correlate with increased reactive oxygen species production, DNA damage, and accelerated tissue aging. However, THs neither raised reactive oxygen species production or matrix metalloproteinase-1, -2 and -9 activity nor decreased sirtuin1 (Sirt1) immunoreactivity. Instead, triiodothyronine increased sirtuin-1, fibrillin-1, proliferator-activated receptor-gamma 1-alpha (PGC1 alpha), collagen I and III transcription, and thyroxine decreased cyclin-dependent kinase inhibitor 2A (p16(ink4)) expression in organ-cultured human skin. Moreover, TH treatment increased intracutaneous fibrillin-rich microfibril and collagen III deposition and decreased mammalian target of rapamycin (mTORC1/2) expression ex vivo. This identifies THs as potent endocrine stimulators of mitochondrial function in human epidermis, which down-regulates rather than enhance the expression of skin aging-related biomarkers ex vivo. Therefore, topically applied THs deserve further exploration as candidate agents for treating skin conditions characterized by reduced mitochondrial function