Validation Empirique de l’Approche Alternative de la Théorie de la Croissance Exogène de Solow, et Stratégie de Croissance pour Madagascar

Il a été récemment établi par Mahazoasy (2023), une approche alternative du modèle de Solow avec technologie exogène. Cette approche alternative, faisant à l’instar du modèle de Solow, l’épargne, la démographie, les taux de dépréciation, de progrès technique et du capital humain, est originale et utile, dans la mesure où elle établit une condition mathématique nécessaire et suffisante pour que s’instaure une croissance à long terme au sein d’une économie. Pour qu’elle puisse être utilisée, il importe, cependant, que cette condition, établie de façon purement théorique, puisse être validée par une approche empirique. On considèrera, pour ce faire, l’économie brésilienne, qui connut une phase de forte croissance à long terme grâce aux bienfaits du transfert de technologies. Une fois cette validation obtenue, il sera possible de recourir au modèle pour déterminer la conditions à la fois nécessaire et suffisante pour qu’un pays pauvre, comme Madagascar, puisse décoller et connaître, à son tour, une croissance à long terme.&nbsp

Calorie restriction increases light-dependent photoreceptor cell loss in the neural retina of fischer 344 rats.

We investigated the effect of \u3e or = 8 months of 40% caloric restriction (CR) on photoreceptor cell loss in 12, 18, and 24 month-old Fischer 344 rats (N = 154). Rats were reared at the NIA Biomarkers Program, National Center for Toxicological Research. Photoreceptor cell density, assessed histologically, declined with age in both the CR-fed and ad lib (AL)-fed cohorts (P \u3c 0.000), but declines were more pronounced in the CR cohort (P \u3c 0.0005). The deleterious effect of CR was most pronounced in the central as opposed to the peripheral retina (P = 0.008), suggesting a light-dependent mechanism. Photoreceptor cell density was inversely associated with rearing under bright light (300-750 lux) as compared with rearing under lower illuminance (\u3c or = 200 lux) (P \u3c 0.0005). However, the deleterious effect of bright light on photoreceptor cell density was more pronounced in the CR cohort (P = 0.04). Effects of CR on circadian activity are likely to increase the actual light exposure of the CR cohort and may explain the apparent inability of CR to delay retinal aging in albino rats

Calorie restriction modulates age-dependent changes in the retinas of brown norway rats [In Process Citation]

The present study examined the effect of a 40% reduction in caloric intake (CR) versus ad libitum (AL) feeding on retinal aging. CR- and AL-fed Brown Norway (BN) rats were obtained at 12, 24 and 30 months of age from the National Center for Toxicological Research (NCTR). Age-dependent declines in outer nuclear layer (ONL=photoreceptor) cell densities, ONL height, inner nuclear layer (INL) cell densities, and thicknesses of the inner retina and whole retina were quantified in thick sections at six loci across the circumference of the sensory retina (four peripheral, two central). Data were analyzed by repeated measures, general linear models. Aging in both diet groups was associated with declines in ONL cell density, ONL height, peripheral INL cell density and total retinal thickness (

Vocal complexity in a socially complex corvid: gradation, diversity and lack of common call repertoire in male rooks

Peer reviewed: TruePublication status: PublishedVocal communication is widespread in animals, with vocal repertoires of varying complexity. The social complexity hypothesis predicts that species may need high vocal complexity to deal with complex social organization (e.g. have a variety of different interindividual relations). We quantified the vocal complexity of two geographically distant captive colonies of rooks, a corvid species with complex social organization and cognitive performances, but understudied vocal abilities. We quantified the diversity and gradation of their repertoire, as well as the inter-individual similarity at the vocal unit level. We found that males produced call units with lower diversity and gradation than females, while song units did not differ between sexes. Surprisingly, while females produced highly similar call repertoires, even between colonies, each individual male produced almost completely different call repertoires from any other individual. These findings question the way male rooks communicate with their social partners. We suggest that each male may actively seek to remain vocally distinct, which could be an asset in their frequently changing social environment. We conclude that inter-individual similarity, an understudied aspect of vocal repertoires, should also be considered as a measure of vocal complexity.</jats:p

Dietary Fiber and the Human Gut Microbiota: Application of Evidence Mapping Methodology

Interest is rapidly growing around the role of the human gut microbiota in facilitating beneficial health effects associated with consumption of dietary fiber. An evidence map of current research activity in this area was created using a newly developed database of dietary fiber intervention studies in humans to identify studies with the following broad outcomes: (1) modulation of colonic microflora; and/or (2) colonic fermentation/short-chain fatty acid concentration. Study design characteristics, fiber exposures, and outcome categories were summarized. A sub-analysis described oligosaccharides and bacterial composition in greater detail. One hundred eighty-eight relevant studies were identified. The fiber categories represented by the most studies were oligosaccharides (20%), resistant starch (16%), and chemically synthesized fibers (15%). Short-chain fatty acid concentration (47%) and bacterial composition (88%) were the most frequently studied outcomes. Whole-diet interventions, measures of bacterial activity, and studies in metabolically at-risk subjects were identified as potential gaps in the evidence. This evidence map efficiently captured the variability in characteristics of expanding research on dietary fiber, gut microbiota, and physiological health benefits, and identified areas that may benefit from further research. We hope that this evidence map will provide a resource for researchers to direct new intervention studies and meta-analyses

Vocal complexity in a socially complex corvid: gradation, diversity and lack of common call repertoire in male rooks

International audienceVocal communication is widespread in animals, with vocal repertoires of varying complexity. The social complexity hypothesis predicts that species may need high vocal complexity to deal with complex social organization (e.g. have a variety of different interindividual relations). We quantified the vocal complexity of two geographically distant captive colonies of rooks, a corvid species with complex social organization and cognitive performances, but understudied vocal abilities. We quantified the diversity and gradation of their repertoire, as well as the inter-individual similarity at the vocal unit level. We found that males produced call units with lower diversity and gradation than females, while song units did not differ between sexes. Surprisingly, while females produced highly similar call repertoires, even between colonies, each individual male produced almost completely different call repertoires from any other individual. These findings question the way male rooks communicate with their social partners. We suggest that each male may actively seek to remain vocally distinct, which could be an asset in their frequently changing social environment. We conclude that inter-individual similarity, an understudied aspect of vocal repertoires, should also be considered as a measure of vocal complexity