Search results for "vit.C"
showing 10 items of 297 documents
Evolution of polarization orientations in a flat universe with vector perturbations: CMB and quasistellar objects
2007
Various effects produced by vector perturbations (vortical peculiar velocity fields) of a flat Friedmann-Robertson-Walker background are considered. In the presence of this type of perturbations, the polarization vector rotates. A formula giving the rotation angle is obtained and, then, it is used to prove that this angle depends on both the observation direction and the emission redshift. Hence, rotations are different for distinct quasars and also for the Cosmic Microwave Background (CMB) radiation coming along different directions (from distinct points of the last scattering surface). As a result of these rotations, some correlations could appear in an initially random field of quasar po…
Prenylated Flavonoids from the Roots of Tephrosia rhodesica
2020
Five new compounds—rhodimer (1), rhodiflavan A (2), rhodiflavan B (3), rhodiflavan C (4), and rhodacarpin (5)—along with 16 known secondary metabolites, were isolated from the CH2Cl2–CH3OH (1:1) extract of the roots of Tephrosia rhodesica. They were identified by NMR spectroscopic, mass spectrometric, X-ray crystallographic, and ECD spectroscopic analyses. The crude extract and the isolated compounds 2–5, 9, 15, and 21 showed activity (100% at 10 μg and IC50 = 5–15 μM) against the chloroquine-sensitive (3D7) strain of Plasmodium falciparum. peerReviewed
A cytological and ultrastructural study on the maturation and germination of oospores of Plasmopara viticola from overwintering vine leaves.
1999
Observations on cytological and ultrastructural changes in Plasmopara viticola oospores were carried out during the overwintering period. Three types of oospores were observed. Type I, characterized by a thin inner oospore wall (IOW), large lipid globules and two nuclei, was recovered only in samples collected in October. These oospores were considered to be immature. Maturation occurred during November and involved a noticeable increase in thickness of the IOW, fusion of nuclei, formation of an ooplast and break up of large lipid globules into smaller ones (type II oospores). A few oospores (type III) showed abnormal organization with very large lipid globules and less frequently discernib…
Pakalpojumu eksportu ietekmējošie faktori
2015
Ekonomiski attīstītajās vai ar derīgajiem un cilvēkresursiem nabadzīgās valstīs pakalpojumu sektora īpatsvars kopējā ekonomikā sastāda lielāko daļu. Taču pētījumos pakalpojumu eksports lielākoties netiek atdalīts no preču eksporta un pētījumi, kuros tas tiktu analizēts, ir parādījušies lielākoties tikai pēdējo 10-15 laikā. Tādēļ šī pētījuma ietvaros tiek analizēti pakalpojumu eksportu ietekmējošie faktori. Tiek izmantots gravitācijas modelis, ar kura palīdzību ir veiksmīgi analizēta ārējā tirdzniecība jau vairāk nekā 50 gadu laikā. Balstoties uz pētījumiem par eksportu no konkrētām valstu grupām, gravitācijas modelim tiek pievienoti papildus faktori. Iegūtie rezultāti pierāda, ka katrai pak…
Las bodegas cooperativas y la comercialización del vino en España durante el siglo XX
2020
Resumen Las bodegas cooperativas surgieron con un doble objetivo: la elaboracion en comun del vino, para reducir los costes de produccion y aumentar la calidad del producto; y la venta en comun del vino, con una reduccion de los intermediarios y una mejora de la posicion de los viticultores en el proceso de comercializacion. Ambos objetivos tenian que suponer una mayor remuneracion del producto y, en consecuencia, del ingreso de los productores, que en el sector vitivinicola eran fundamentalmente pequenos agricultores familiares, enfrentados a un contexto de caida tendencial de los precios del vino. En este articulo realizamos una primera aproximacion al papel de las bodegas cooperativas en…
Soil water erosion on Mediterranean vineyards: A review
2016
Soil water erosion on cultivated lands represents a severe threat to soil resources in the world, and especially in Mediterranean areas, due to their topographic, edaphic and climatic conditions. Among the cultivated lands, vineyards deserve a particular attention because, aside representing one of the most important crops in terms of income and employment, they also have proven to be the form of agricultural use that causes one of the highest soil losses. Although the topic of soil water erosion on vineyards has been studied, it still raises uncertainties, due to the high variability of procedures for data acquisition, which consists into different scales of analysis and measurement method…
Climate change and risk management policies in viticulture
2022
In recent years, the adverse effects of climate change on agricultural productivity have been increasing dramatically. As a function of this situation, in many ter-ritorial contexts, productivity and profitability decrease due to uncontrollable events. In light of this situation, the entrepreneur should adopt strategies to decrease the risks of climate change and sustain agricultural productivity and farm profitability. The research used case studies of several wine-growing facilities of companies located in the Mediterranean area. The study estimated the losses of productivity and thus income due to climate change, which is occurring with increasing in-tensity. Subsequently, through the in…
Comparison between energy balance and mass balance models for actual evapotranspiration assessment
2009
The assessment of the water needs for a specific crop has a fundamental importance in the management of water resources. The application of empirical models able to retrieve estimates of the actual evapotranspiration (ETa) to assess the need for water could give a valid tool for the planning of water supply, avoiding unnecessary water losses. In this context, two independent models for estimating actual evapotranspiration were compared. The first model is based on an energy balance and uses remotely sensed data and ancillary data from weather stations to assess the ETa. The second model also uses remotely sensed data and climatic data on a daily basis from a weather network. Field measureme…
Le géographe et l'expertise dans le domaine des vins
2008
International audience; Le géographe semble avoir une certaine légitimité à intervenir dans le domaine des vins, et donc à être expert : tenir le rôle d'une personne choisie pour ses connaissances et chargée de solutionner un problème, une contestation, un procès ; ou de façon plus générale, à être capable de guider, de conseiller, d'éclairer. En particulier dans la construction d'espaces voués à une production agricole de qualité. Toute la question est bien sûr de mesurer leur insertion dans le monde professionnel, d'appréhender leurs moyens, leurs méthodes, leurs outils, comment et avec qui ils définissent des territoires du vin ? Enfin, et peut être surtout : répondent-ils aux nouvelles …