How Useful Are Environmental Safety Standards in Economics - the Example of Safe Minimum Standards for Protection of Species

The use of environmental safety standards is being increasingly advocated, and economists are being increasingly required to adapt their policy models to take account of such standards, e.g. by the use of transferable environmental damage quotas. The use of these standards may be a consequence of a greater desire to achieve more sustainable development and preserve the natural wealth available to future generations. An important means to this goal is to preserve biodiversity and genetic variability. Safe minimum standards for conservation of wildlife have been suggested as a way to achieve this. Sometimes safe minimum standards for conservation of species are defined in terms of their minimum viable populations and their minimum habitat requirements. However, as a review of recent scientific literature indicates, these safe minimum standards are very uncertain

La pharmacopée royale galénique et chimique de Moyse Charas

Cette thèse comporte trois parties distinctes : 1) Un aperçu de l'histoire médicale et pharmaceutique au XVIIème siècle. 2) La biographie de Moyse Charas, auteur de la Pharmacopée Royale. 3) Une étude de La Pharmacopée Royale Galénique et Chimique. Le XVIIème siècle a été marqué par de grandes découvertes comme, la circulation du sang par Harvey, la mise au point du microscope, des descriptions médicales de plus en plus précises, l'utilisation du quinquina. Certains médecins, s'attachèrent à ramener les esprits vers la clinique, l'observation et l'expérience. La pharmacopée Royale Galénique et Chimique est un ouvrage didactique, qui reflète les cours assurés par Moyse Charas au Jardin Royal des Plantes de Paris L'étude de la Pharmacopée chimique de Charas nous montre qu'au XVIIème siècle la distillation reste le procédé de prédilection des chimistes et que tout l'art de ces derniers consiste à l'appliquer aux matières les plus diverses, sinon les plus étranges.CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Fluorescence characteristics and photoinhibition in saplings of manwood on clear days and under overcast conditions Características da fluorescência e fotoinibição em arvoretas de acariquara em dias nublados e ensolarados

High irradiance may reduce the productivity of tropical plants by exacerbating photoinhibition of photosynthesis, particularly in the case of shade-adapted plants. The aim of this study was to determine the effect of cloud cover on the fluorescence characteristics and photoinhibition on saplings of manwood (Minquartia guianensis Aubl.). Three-year-old saplings were exposed to full irradiance either on clear days (10, 45 and 90 min) or under overcast conditions (120, 180, and 420 min). Changes in the population of functional photosystem II (PSII), the initial (Fo) and maximum fluorescences (Fm), and the Fv/Fm ratio (maximum potential quantum yield of PSII) were monitored after plant exposure to full irradiance and during recovery (within 48 h) at low light intensity. Although photoinhibition of PSII (Fv/Fm) was determined by the number of photons reaching the leaf surface (photon fluence), cloudiness tended to reduce the photoinhibitory effect of irradiance. Fo increased with fluence on cloudy days and was unaffected by irradiance on clear days, except for a sharp rise during the first 10 min of exposure to full sunlight. For a given photon fluence, Fm was lower on clear days. Recovery from photoinhibition was similar in both light environments. Although photon fluence is the preponderant factor determining the extent of photoinhibition, cloudiness might alleviate the photoinhibitory effect of irradiance.<br>Alta irradiância pode reduzir a produtividade de plantas tropicais por intensificar a fotoinibição da fotossíntese, particularmente em plantas adaptadas à sombra. O objetivo deste trabalho foi determinar o efeito da nebulosidade nas características da fluorescência e na fotoinibição em arvoretas de acariquara (Minquartia guianensis Aubl.). Plantas jovens de três anos de idade foram expostas à irradiância em dias ensolarados (10, 45 e 90 min) ou nublados (120, 180 e 420 min). Foram monitoradas mudanças na população de fotossistemas II (FSII) funcionais, na fluorescência inicial (Fo) e máxima (Fm) e na relação Fv/Fm (rendimento quântico potencial do FSII), antes da exposição das plantas à irradiância e durante a recuperação (até 48 h) sob baixa intensidade luminosa. Apesar de a fotoinibição (Fv/Fm) ser determinada pelo número de fótons incidentes na superfície da folha (fluência), houve tendência de a nebulosidade reduzir o efeito da irradiância na fotoinibição. Fo aumentou com a fluência em dias nublados, mas não em dias ensolarados, exceto pelo aumento nos primeiros 10 min de exposição à luz solar plena. Para uma dada fluência, Fm foi menor nos dias ensolarados. A recuperação da fotoinibição foi similar em ambos os ambientes de luz. Apesar de a fluência de fótons ser o fator preponderante na determinação do grau de fotoinibição, a nebulosidade ameniza o efeito fotoinibitório da irradiância