750 resultados para amour courtois
Resumo:
1. As trees in a given cohort progress through ontogeny, many individuals die. This risk of mortality is unevenly distributed across species because of many processes such as habitat filtering, interspecific competition and negative density dependence. Here, we predict and test the patterns that such ecological processes should inscribe on both species and phylogenetic diversity as plants recruit from saplings to the canopy. 2. We compared species and phylogenetic diversity of sapling and tree communities at two sites in French Guiana. We surveyed 2084 adult trees in four 1-ha tree plots and 943 saplings in sixteen 16-m2 subplots nested within the tree plots. Species diversity was measured using Fisher's alpha (species richness) and Simpson's index (species evenness). Phylogenetic diversity was measured using Faith's phylogenetic diversity (phylogenetic richness) and Rao's quadratic entropy index (phylogenetic evenness). The phylogenetic diversity indices were inferred using four phylogenetic hypotheses: two based on rbcLa plastid DNA sequences obtained from the inventoried individuals with different branch lengths, a global phylogeny available from the Angiosperm Phylogeny Group, and a combination of both. 3. Taxonomic identification of the saplings was performed by combining morphological and DNA barcoding techniques using three plant DNA barcodes (psbA-trnH, rpoC1 and rbcLa). DNA barcoding enabled us to increase species assignment and to assign unidentified saplings to molecular operational taxonomic units. 4. Species richness was similar between saplings and trees, but in about half of our comparisons, species evenness was higher in trees than in saplings. This suggests that negative density dependence plays an important role during the sapling-to-tree transition. 5. Phylogenetic richness increased between saplings and trees in about half of the comparisons. Phylogenetic evenness increased significantly between saplings and trees in a few cases (4 out of 16) and only with the most resolved phylogeny. These results suggest that negative density dependence operates largely independently of the phylogenetic structure of communities. 6. Synthesis. By contrasting species richness and evenness across size classes, we suggest that negative density dependence drives shifts in composition during the sapling-to-tree transition. In addition, we found little evidence for a change in phylogenetic diversity across age classes, suggesting that the observed patterns are not phylogenetically constrained.
Resumo:
VEGF is considered as an important factor in the pathogenesis of macular edema. VEGF induces the rupture of the blood retinal barrier and may also influence the retinal pigment epithelial (RPE) outer retinal barrier. The aim of this work was to analyze the influence of the VEGF receptor pathways in the modulation of the RPE barrier breakdown in vitro and in vivo. The ARPE19 human junctions in culture are modulated by VEGF through VEGFR-1 but not through VEGFR-2. PlGF-1, that is a pure agonist of VEGFR-1, is produced in ARPE-19 cells under hypoxic conditions and mimics VEGF effects on the external retinal barrier as measured by TER and inulin flux. In vivo, the intravitreous injection of PlGF-1 induces a rupture of the external retinal barrier together with a retinal edema. This effect is reversible within 4 days. VEGF-E, that is a pure agonist of VEGFR-2, does not induce any acute effect on the RPE barrier. These results demonstrate that PlGF-1 can reproduce alterations of the RPE barrier occurring during diabetic retinopathy.
Resumo:
PURPOSE: The antiangiogenic effect of an antisense oligodeoxynucleotide (ODN) targeting insulin receptor substrate (IRS)-1 was evaluated on rat corneal neovascularization. METHODS: Eyes with neovessels were treated with subconjunctival injections of IRS-1 antisense oligonucleotide (ASODN), IRS-1 sense ODN (SODN), or PBS. At 8 and 24 hours after the first subconjunctival injection, the expression of IRS-1, VEGF, and IL-1beta mRNA was evaluated. IRS-1 protein levels were also measured at 8 hours by Western blot analysis (n = 4/group). On day 10, corneal neovascularization was quantified in flatmount corneas of rats treated daily from days 4 to 9. RESULTS: On day 10, new vessels covered 95.5% +/- 4% of the corneal area in PBS-treated eyes, 92% +/- 7% in SODN-treated eyes and 59% +/- 20% in ASODN-treated eyes (P < 0.001). In the ASODN-treated group, the expression and synthesis of IRS-1 were significantly downregulated when compared with the control groups. ASODN did not significantly affect the expression of VEGF but significantly decreased the expression of IL-1beta at 24 hours (P = 0.04). CONCLUSIONS: Subconjunctival injections of IRS-1 antisense ODN significantly inhibit rat corneal neovascularization. This effect may be mediated by a downregulation of IL-1beta. IRS-1 proteins may be interesting targets for the regulation of angiogenesis mediated by insulin, hypoxia, or inflammation.
Resumo:
The empirical literature on the asset allocation and medical expenditures of U.S. households consistently shows that risky portfolio shares are increasing in both wealth and health whereas health investment shares are decreasing in these same variables. Despite this evidence, most of the existing models treat financial and health-related choices separately. This paper bridges this gap by proposing a tractable framework for the joint determination of optimal consumption, portfolio and health investments. We solve for the optimal rules in closed form and show that the model can theoretically reproduce the empirical facts. Capitalizing on this closed-form solution, we perform a structural estimation of the model on HRS data. Our parameter estimates are reasonable and confirm the relevance of all the main characteristics of the model.
Resumo:
Le but de cet article est de montrer à l'aide d'un exemple concret comment les catégories « biographie » et « hagiographie » posent problème dans la discipline d'histoire comparée des religions. Il ne s'agit pas de traiter de la biographie ou de l'hagiographie en tant que genres littéraires, mais bien de voir comment se différencient, dans plusieurs types de récits sur la vie et l'oeuvre, les éléments hagiographiques et les éléments biographiques. Pour ce faire, je me concentrerai sur un personnage : la poétesse mystique Mīrābāī, qui a vécu au XVIe siècle de notre ère en Inde du Nord. Ce cas me paraît être intéressant puisque nous n'avons aucun matériel qui permette de rendre des conclusions définitives sur la vie de ce personnage qu'on postule comme historique. Mīrābāī n'a pas laissé de journal intime, de chroniques, ni d'autobiographie. Elle était une femme dévouée au dieu Krishna, une poétesse visant à vivre pleinement sa relation à une entité supra- humaine postulée culturellement, le dieu masculin, Krishna. Ce type de dévotion amoureuse, impliquant une relation d'amour total et d'abandon pour une divinité de prédilection, est appelé bhakti.
Resumo:
PURPOSE: Retinal degeneration has been associated with iron accumulation in age-related macular degeneration (AMD), and in several rodent models that had one or several iron regulating protein impairments. We investigated the iron concentration and the protective role of human transferrin (hTf) in rd10 mice, a model of retinal degeneration. METHODS: The proton-induced X-ray emission (PIXE) method was used to quantify iron in rd10 mice 2, 3, and 4 weeks after birth. We generated mice with the β-phosphodiesterase mutation and hTf expression by crossbreeding rd10 mice with TghTf mice (rd10/hTf mice). The photoreceptor loss and apoptosis were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling in 3-week-old rd10/hTf mice and compared with 3-week-old rd10 mice. The neuroprotective effect of hTf was analyzed in 5-day-old rd10 mice treated by intraperitoneal administration with hTf for up to 25 days. The retinal hTf concentrations and the thickness of the outer nuclear layer were quantified in all treated mice at 25 days postnatally. RESULTS: PIXE analysis demonstrated an age-dependent iron accumulation in the photoreceptors of rd10 mice. The rd10/hTf mice had the rd10 mutation, expressed high levels of hTf, and showed a significant decrease in photoreceptor death. In addition, rd10 mice intraperitoneally treated with hTf resulted in the retinal presence of hTf and a dose-dependent reduction in photoreceptor degeneration. CONCLUSIONS: Our results suggest that iron accumulation in the retinas of rd10 mutant mice is associated with photoreceptor degeneration. For the first time, the enhanced survival of cones and rods in the retina of this model has been demonstrated through overexpression or systemic administration of hTf. This study highlights the therapeutic potential of Tf to inhibit iron-induced photoreceptor cell death observed in degenerative diseases such as retinitis pigmentosa and age-related macular degeneration.
Resumo:
Raras vezes reflectimos sobre as relações e paralelismos existentes entre o trabalho do historiador e do jornalista. Embora os dois descrevam a realidade, as preocupações e os objectivos são bem diferentes. O que une os dois campos de actividade humana é a dependência da fonte, como condicionante de qualquer trabalho jornalístico ou histórico. No caso do trabalho jornalístico os padrões de qualidade incluem também actualidade dos trabalhos produzidos, o que provoca evidentemente um stress e muitas vezes obriga a sacrificar o aprofundamento das questões. O historiador, por seu lado, não é pressionado no trabalho pela deadline quase imediata, mas muito raras vezes dispõe das fontes directas. De qualquer forma, o jornalismo como tal, fica em relação de interdependência quer com a literatura, o que já foi suficientemente comentado e estudado, quer com a história.
Resumo:
PURPOSE: To evaluate the effect of intraocular administration of nitric oxide (NO) donors in the rabbit eye on intraocular pressure (IOP), inflammation, and toxicity. METHODS: Intravitreal and intracameral injections of two NO donors, SIN-1 and SNAP, and SIN-1C and BSS were performed. Clinical examination, IOP measurements, protein evaluation in aqueous humor, and histologic analysis of the ocular globes were realized. Nitric oxide release was demonstrated by nitrite production in the aqueous humor and in the vitreous using the Griess reaction. RESULTS: The drastic decrease of IOP, observed after a single NO donor injection, was correlated directly with nitrite production and, thus, to NO release. Injection of inactive metabolite of SIN-1, SIN-1C, which is not able to release NO, did not modulate IOP. When administered in the aqueous humor or in the vitreous, NO did not diffuse from one segment of the eye to another. No inflammation or histologic damage was observed as a result of a single NO donor administration. CONCLUSIONS: Nitric oxide is implicated directly in the regulation of IOP and its acute, and massive release into the rabbit eye did not induce inflammation or other growth toxic effects on the ocular tissues.
Resumo:
PURPOSE: To investigate the involvement of the cornea during endotoxin-induced uveitis (EIU) in the rat and the effect of Ngamma-nitro-L-arginine methyl ester (L-NAME) as nitric oxide synthase (NOS) inhibitor, administered by iontophoresis. METHODS: EIU was induced in Lewis rats that were killed at 8 and 16 hours after lipopolysaccharide (LPS) injection. The severity of uveitis was evaluated clinically at 16 hours, and nitrite levels were evaluated in the aqueous humor at 8 hours. Corneal thickness was measured, 16 hours after LPS injection, on histologic sections using an image analyzer. Transmission electron microscopy (TEM) was used for fine analysis of the cornea. Transcorneoscleral iontophoresis of L-NAME (100 mM) was performed either at LPS injection or at 1 and 2 hours after LPS injection. RESULTS: At 16 hours after LPS injection, mean corneal thickness was 153.7+/-5.58 microm in the group of rats injected with LPS (n=8) compared with 126.89+/-11.11 microm in the saline-injected rats (n=8) (P < 0.01). TEM showed stromal edema and signs of damage in the endothelial and epithelial layers. In the group of rats treated by three successive iontophoreses of L-NAME (n=8), corneal thickness was 125.24+/-10.36 microm compared with 146.76+/-7.52 microm in the group of rats treated with iontophoresis of saline (n=8), (P=0.015). TEM observation showed a reduction of stromal edema and a normal endothelium. Nitrite levels in the aqueous humor were significantly reduced at 8 hours by L-NAME treatment (P=0.03). No effect on corneal edema was observed after a single iontophoresis of L-NAME at LPS injection (P=0.19). Iontophoresis of saline by itself induced no change in corneal thickness nor in TEM structure analysis compared with normal rats. CONCLUSIONS: Corneal edema is observed during EIU. This edema is significantly reduced by three successive iontophoreses of L-NAME, which partially inhibited the inflammation. A role of nitric oxide in the corneal endothelium functions may explain the antiedematous effect of L-NAME.
Resumo:
Contient : 1 « Deul et ennuy... » ; 2 « Beata es, Maria... » ; 3 « Da pacem, Domine... » ; 4 « Da pacem, Domine... » ; 5 « Dulcis amica Dei... » ; 6 « Si sumpsero... » ; 7 « O quam glorifica... » ; 8 « Si dedero... » ; 9 « Mes pensées... » ; 10 « L'eure est venue... » ; 11 « Despitant fortune... » ; 12 « Allez, regretz... » ; 13 « Les grans regretz... » ; 14 « Va t'em, regret... » ; 15 « Qui belles amours a... » ; 16 « Se je vous eslongne... » ; 17 « Helas! de vous certes... » ; 18 « Si vous voulez estre... » ; 19 « N'ay ge pas droit... » ; 20 « Ha! qu'il m'ennuye... » ; 21 « Seul et eureux... » ; 22 « La saison en est... » ; 23 « Penser en vous... » ; 24 « Venez, regretz... » ; 25 « Des fais mondains... » ; 26 « De plus en plus... » ; 27 « Mon souvenir... » ; 28 « A heur le tiens... » ; 29 « Tant ay d'ennuyt... » ; 30 « Comme femme desconfortée... » ; 31 « Si congié prens... » ; 32 « Se mieulx ne vient... » ; 33 « Plus que aultre... » ; 34 « En l'ombre d'ung buyssonnet... » ; 35 « La regrettée... » ; 36 « Je sçay tout... » ; 37 « Fors seullement... » ; 38 « Il n'est vivant... » ; 39 « Vostre beaulté... » ; 40 « Helas ! pourquoy... » ; 41 « Je ne viz oncques... » ; 42 « Royne dez flours... » ; 43 « Faisons boutons... » ; 44 « Fin ch'yo vivo... » ; 45 « Yo so contento... » ; 46 « Que vous ma dame... » ; 47 « La gaye pastoure... » ; 48 « Se j'ay perdu mon amy... » ; 49 « Mon seul plaisir... » ; 50 « Ce moys de may... » ; 51 « Si fayt il vous... » ; 52 « Pastourelle... » ; 53 « Belle, se j'avoye... » ; 54 « Amoureuse m'y fault estre... » ; 55 « Tant bel m'y sont... » ; 56 « Se j'avoye de la soie... » ; 57 « Lourdault... » ; 58 « L'autre jour m'y chevauchoye... » ; 59 « La nuyt s'en va... » ; 60 « Il estoit ung bon homme... » ; 61 « Fors seulement... » ; 62 « Crux triumphans... » ; 63 « Jesus, dignum nomen... » ; 64 « My levay... » ; 65 « Mary de par sa mere... » ; 66 « La cuiller d'or... » ; 67 « Faictes, s'il vous plait... » ; 68 « Ne par Dieu... » ; 69 « Seullette suis... » ; 70 « Mon mari m'a diffamée... » ; 71 « L'amour de moy est enclose... » ; 72 « Mannette m'a mandé... » ; 73 « A l'ombre du bissonnet... » ; 74 « Triste et pensif... » ; 75 « Cum summo... »
Resumo:
Cet article présente les résultats d'une enquête socio-ethnographique (entretiens et observations) au sein de la presse quotidienne sportive romande. Il révèle deux registres vocationnels au sein des journalistes de sport, dans un contexte de féminisation de ce groupe professionnel: là où les hommes évoquent une vocation pour le journalisme sportif, déclinée sur le mode de la passion sportive, les femmes revendiquent plus volontiers un amour de l'écriture et du journalisme. Liés à des modalités d'accès à la profession, des ressources et des socialisations professionnelles bien différenciés, ils induisent d'une part des modes d'investissement de la profession différents et d'autre part expliquent en grande part les ségrégations horizontales et verticales auxquelles les femmes journalistes doivent faire face.
Resumo:
Despite clear evidence of correlations between financial and medical statuses and decisions, most models treat financial and health-related choices separately. This article bridges this gap by proposing a tractable dynamic framework for the joint determination of optimal consumption, portfolio holdings, health investment, and health insurance. We solve for the optimal rules in closed form and capitalize on this tractability to gain a better understanding of the conditions under which separation between financial and health-related decisions is sensible, and of the pathways through which wealth and health determine allocations, welfare and other variables of interest such as expected longevity or the value of health. Furthermore we show that the model is consistent with the observed patterns of individual allocations and provide realistic estimates of the parameters that confirm the relevance of all the main characteristics of the model.