607 research outputs found
A new scorpion species of the genus \u3ci\u3eButhus\u3c/i\u3e Leach, 1815 (Scorpiones, Buthidae) from Morocco
A new species belonging to the genus Buthus Leach (Scorpiones, Buthidae) is described from northeast of Tarfaya in the extreme southwest of Morocco. The new species does not belong to the “Buthus occitanus species complex”, but is rather associated with Buthus atlantis Pocock, species also known from the southern of Morocco. With the description of Buthus bonito sp. n., t Morocco is raised to 12. A checklist of these species is provided
L’institutionnalisation de la raison : le système de philosophie du droit de Robert Alexy et ses limites
Robert Alexy developed a legal philosophy which, aligning with the neo-constitutionalist paradigm, claimed to overcome the classic alternative between positivism and natural law. This claim led him to posit a theory of law, rights, and practical argumentation that culminated in the formulation of an “inclusive non-positivist” concept of law. The present investigation purports to reconstruct critically and systematically two central aspects of Alexy’s theory in the light of the central idea that structures his thought: “the institutionalization of reason” understood as the effort to reconcile the real and the ideal dimensions of law. The first chapter aims at contextualizing his work in view of its philosophical and legal sources of inspiration and at analyzing his metaphilosophy. It will be shown that besides the clear analytical and Kantian inheritance at work in his thought, the metaphysical theses he puts forth render its internal coherence difficult to maintain. The second chapter, dedicated to the study of his ideas regarding the nature and the concept of law, results in a critique of the “pretention to correctness” as well as of the establishment of the existence of human rights. It concludes that the foundation of the “inclusive non-positivism” he advocates is doubtful. Finally, the third chapter, which analyzes his theory of general practical discourse and legal argumentation, criticizes the logico-transcendental foundation of the discourse rules as well as of his metaethics. This critique unveils the prescriptive and ideological dimensions at work in his legal philosophy. Given the theoretical shortcomings of his work, his legal philosophy does not constitute a satisfactory “third way” between positivism and natural law. Nevertheless, it is an interesting attempt that illustrates, through its wide international reception, the contemporary aspiration to protect the fundamental liberties and rights of citizens in modern constitutional states.Robert Alexy a développé une philosophie du droit qui, dans la droite lignée du néo-constitutionnalisme, porte l’ambition de dépasser l’alternative classique qui oppose positivisme et jusnaturalisme. Cela le conduit à formuler une théorie du droit, des droits et de l’argumentation pratique qui culmine dans la formulation d’un concept « non-positiviste inclusif » de droit. Cette investigation propose une reconstruction critique et systématique de deux aspects centraux de la philosophie du droit de Robert Alexy à l’aune de l’idée centrale qui structure tout le programme théorique du juriste allemand : « l’institutionnalisation de la raison » conçue comme l’ambition de réconcilier la dimension réelle et idéale du droit. Le premier chapitre s’attache, d’une part, à contextualiser son œuvre à l’aune de ses sources d’inspirations philosophiques et juridiques ainsi que, d’autre part, à analyser sa métaphilosophie. Il révèle en outre que malgré l’héritage analytique et kantien qui structure son œuvre, les thèses proprement métaphysiques qu’il développe rendent la cohérence de sa pensée difficile à maintenir. Le deuxième chapitre, dédié à l’étude de ses développements relatifs au concept et à la nature du droit, se solde par une critique de la thèse de la « prétention de correction » et de l’établissement de l’existence des droits de l’homme qui permet de douter du bien-fondé du « non-positivisme inclusif » qu’il défend. Enfin, le dernier chapitre, dédié à l’analyse de sa théorie du discours pratique général ainsi qu’à sa théorie de l’argumentation juridique, propose une critique de la fondation logico-transcendantale des règles du discours et de sa métaéthique qui révèle le caractère essentiellement idéologique et prescriptif de son travail. Bien que les difficultés qui grèvent sa théorie sont insusceptibles de lui permettre de constituer une « troisième voie » entre positivisme et jusnaturalisme, son œuvre présente un intérêt historique indéniable et illustre, par l’ampleur de sa réception internationale, l’aspiration contemporaine à la protection des droits fondamentaux et à la réalisation de l’État de droit
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Development and pathology of the hyaloid, choroidal and retinal vasculature
During embryogenesis, the development and differentiation of the eye requires the concomitant formation of the neural/glial elements along with a dense vascular network. The adult neural retina is supported by two distinct vascular systems, the proper retinal vessels and the choroidal vessels. The two beds differ not only in their pattern of embryonic differentiation, but also in their function in the adult organism. The retinal vasculature has barrier properties similar to those observed in the brain, whereas the choroidal vessels display a highly fenestrated phenotype. The hyaloid vasculature is a transient embryonic vascular bed which is complete at birth in mammals and regresses contemporaneously with the formation of the retinal vasculature. The dependence of the retina on its blood supply makes it highly vulnerable to any vascular changes and indeed ocular diseases, such as proliferative retinopathy, age-related macular degeneration and the hyperplastic primary vitreous, which are associated with abnormalities of the different vascular beds of the eye. A number of factors have been implicated in developmental and pathological changes in vessel formation and regression, including fibroblast growth factors, platelet-derived endothelial growth factor and vascular endothelial growth factor, among others. The purpose of this review is to describe and discuss new insights into the mechanisms and molecular cues involved in the development of the normal and pathological vascular systems of the eye. The characterization of the molecules and cell-cell interactions involved in the formation, stabilization and regression of new vessels has led to the identification of potential control points for therapeutic intervention
Long-distance wind-borne dispersal of the moth Cornifrons ulceratalis (Lepidoptera: Crambidae: Evergestinae) into the northern Mediterranean
On October 2006, during an episode of abnormally warm weather, the African moth Cornifrons ulceratalis (Lederer, 1858) was captured simultaneously for the first time in several sites in north-eastern Spain, the Balearic Islands and southern France. A deep depression situated over the Atlantic at the time gave rise to warm south-westerly winds, accompanied by suspended dust, that blew towards the north-western Mediterranean Basin. Back trajectories of air masses at two different altitudinal levels indicate that the moths most probably originated from an area located in Morocco and northern Algeria, where C. ulceratalis can be extremely abundant. With winter approaching, this invasion of a typically non-migratory species into the north-western Mediterranean Basin provides a good example of the so-called "pied piper" phenomenon, by which wind-borne insects may be carried into areas unfavourable for survival or reproduction. However, because climate change may make the establishment of this and other African species more likely in the future, we suggest that monitoring of this process may become an essential issue in the coming years
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Fatty Acid Binding Protein 4 Deficiency Protects against Oxygen-Induced Retinopathy in Mice
Retinopathy of prematurity (ROP) is a leading cause of blindness in children worldwide due to increasing survival rates of premature infants. Initial suppression, followed by increased production of the retinal vascular endothelial growth factor-A (VEGF) expression are key events that trigger the pathological neovascularization in ROP. Fatty acid binding protein 4 (FABP4) is an intracellular lipid chaperone that is induced by VEGF in a subset of endothelial cells. FABP4 exhibits a pro-angiogenic function in cultured endothelial cells and in airway microvasculature, but whether it plays a role in modulation of retinal angiogenesis is not known. We hypothesized that FABP4 deficiency could ameliorate pathological retinal vascularization and investigated this hypothesis using a well-characterized mouse model of oxygen-induced retinopathy (OIR). We found that FABP4 was not expressed in retinal vessels, but was present in resident macrophages/microglial cells and endothelial cells of the hyaloid vasculature in the immature retina. While FABP4 expression was not required for normal development of retinal vessels, FABP4 expression was upregulated and localized to neovascular tufts in OIR. FABP4−/− mice demonstrated a significant decrease in neovessel formation as well as a significant improvement in physiological revascularization of the avascular retinal tissues. These alterations in retinal vasculature were accompanied by reduced endothelial cell proliferation, but no effect on apoptosis or macrophage/microglia recruitment. FABP4−/− OIR samples demonstrated decreased expression of genes involved in angiogenesis, such as Placental Growth Factor, and angiopoietin 2. Collectively, our findings suggest FABP4 as a potential target of pathologic retinal angiogenesis in proliferative retinopathies
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Identification of a synergistic interaction between endothelial cells and retinal pigment epithelium
Abstract The retinal pigment epithelium located between the neurosensory retina and the choroidal vasculature is critical for the function and maintenance of both the photoreceptors and underlying capillary endothelium. While the trophic role of retinal pigment epithelium on choroidal endothelial cells is well recognized, the existence of a reciprocal regulatory function of endothelial cells on retinal pigment epithelium cells remained to be fully characterized. Using a physiological long‐term co‐culture system, we determined the effect of retinal pigment epithelium‐endothelial cell heterotypic interactions on cell survival, behaviour and matrix deposition. Human retinal pigment epithelium and endothelial cells were cultured on opposite sides of polyester transwells for up to 4 weeks in low serum conditions. Cell viability was quantified using a trypan blue assay. Cellular morphology was evaluated by H&E staining, S.E.M. and immunohistochemistry. Retinal pigment epithelium phagocytic function was examined using a fluorescent bead assay. Gene expression analysis was performed on both retinal pigment epithelium and endothelial cells by quantitative PCR. Quantification of extracellular matrix deposition was performed on decellularized transwells stained for collagen IV, fibronectin and fibrillin. Our results showed that presence of endothelial cells significantly improves retinal pigment epithelium maturation and function as indicated by the induction of visual cycle‐associated genes, accumulation of a Bruch's membrane‐like matrix and increase in retinal pigment epithelium phagocytic activity. Co‐culture conditions led to increased expression of anti‐angiogenic growth factors and receptors in both retinal pigment epithelium and endothelial cells compared to monoculture. Tube‐formation assays confirmed that co‐culture with retinal pigment epithelium significantly decreased the angiogenic phenotype of endothelial cells. These findings provide evidence of critical interdependent interactions between retinal pigment epithelium and endothelial cell involved in the maintenance of retinal homeostasis
Modelling the distribution of the Ocellated Lizard in France : implications for conservation
The Ocellated Lizard, Timon lepidus (Daudin 1802) occupies the Mediterranean regions of southwestern Europe (Portugal, Spain, France, and the extreme northwest of Italy). Over the last decades, a marked decline in its population has been observed, particularly on the northern edge of its distribution. As a result, it is currently considered a threatened species, especially in France and Italy. In France, a national action plan for its conservation has been put in place. In this study, ecological niche modelling (ENM) was carried out over the entire area of France in order to evaluate the species' potential distribution, more accurately define its ecological niche, guide future surveys, and inform land use planning so this species can be better taken into consideration. The modelling used data representing 2,757 observation points spread over the known range of the species, and 34 ecogeographical variables (climate, topography, and vegetation cover) were evaluated. After removing correlated variables, models were fitted with several combinations of variables using eight species distribution model (SDM) algorithms, and then their performance was assessed using three model accuracy metrics. Iterative trials changing the input variables were used to obtain the best model. The optimized model included nine determining variables. The results indicate the presence of this species is linked primarily to three climate variables: precipitation in the driest month, precipitation seasonality, and mean temperature in the driest quarter. The model was checked by a sample dataset that was not used to fit the model, and this validation dataset represented 25% of the overall field observations. Of the known occurrence locations kept aside to check the results, 94% fell within the presence area predicted by the modelled map with a presence probability greater than 0.7, and 90% fell within the area with a presence probability ranging from 0.8 to 1, which represents a very high predictive value. These results indicate that the models closely matched the observed distribution, suggesting a low impact of either geographical factors (barriers to dispersal), historical factors (dispersal process), or ecological factors (e.g., competition, trophic resources). The overlap between the predicted distribution and protected areas for this species reveals that less than 1% of the potential distribution area is protected by strong regulatory measures (e.g., national parks and natural reserves). The knowledge obtained in this study allows us to recommend some guidelines that would favor the conservation of this species.Peer reviewe
VEGF and TGF-β are required for the maintenance of the choroid plexus and ependyma
Although the role of vascular endothelial growth factor (VEGF) in developmental and pathological angiogenesis is well established, its function in the adult is less clear. Similarly, although transforming growth factor (TGF) β is involved in angiogenesis, presumably by mediating capillary (endothelial cell [EC]) stability, its involvement in quiescent vasculature is virtually uninvestigated. Given the neurological findings in patients treated with VEGF-neutralizing therapy (bevacizumab) and in patients with severe preeclampsia, which is mediated by soluble VEGF receptor 1/soluble Fms-like tyrosine kinase receptor 1 and soluble endoglin, a TGF-β signaling inhibitor, we investigated the roles of VEGF and TGF-β in choroid plexus (CP) integrity and function in adult mice. Receptors for VEGF and TGF-β were detected in adult CP, as well as on ependymal cells. Inhibition of VEGF led to decreased CP vascular perfusion, which was associated with fibrin deposition. Simultaneous blockade of VEGF and TGF-β resulted in the loss of fenestrae on CP vasculature and thickening of the otherwise attenuated capillary endothelium, as well as the disappearance of ependymal cell microvilli and the development of periventricular edema. These results provide compelling evidence that both VEGF and TGF-β are involved in the regulation of EC stability, ependymal cell function, and periventricular permeability
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Expression and Role of VEGF-A in the Ciliary Body
Purpose.: The role of VEGF-A in the normal ciliary body is largely unexplored. The ciliary body is similar in many respects to the choroid plexus of the brain, and we demonstrated previously the importance of VEGF-A in maintenance of choroid plexus vasculature and ependymal cells. Therefore, the role of VEGF-A in ciliary body homeostasis was explored.
Methods.: Swiss-Webster mice (VEGF-LacZ) were used to determine VEGF-A expression during ciliary body development and in the adult. VEGFR2 expression was determined in adult wild type C56BL/6J mice. Systemic VEGF-A neutralization in vivo was achieved with adenovirus-mediated overexpression of soluble VEGFR1 (sFlt1). Following VEGF-A neutralization, the ciliary epithelium was analyzed by light microscopy and transmission electron microscopy (TEM). The effect of VEGF-A blockade on ciliary body function also was assessed by measuring intraocular pressure.
Results.: VEGF-A expression was detected at embryonic day 18.5 (E18.5), the onset of ciliary process formation. In the adult ciliary body, VEGF-A was expressed by the pigmented epithelium, whereas VEGFR2 was localized primarily to the capillary endothelium and nonpigmented epithelium. Systemic VEGF-A neutralization led to a thinning of the nonpigmented epithelium, vacuolization of the pigmented epithelium, loss of capillary fenestrations, and thrombosis. These changes were associated with impaired ciliary body function, as evidenced by decreased intraocular pressure in sFlt1-overexpressing animals (15.31 ± 2.06 mm Hg) relative to controls (18.69 ± 1.49 mm Hg).
Conclusions.: VEGF-A has an important role in ciliary body homeostasis. Potential for undesired off-target effects should be considered with the chronic use of anti–VEGF-A therapies
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