5,742 research outputs found
W. E. B. Du Bois FBI Files (FOIA)
No full textCovers period 1942-1960.
William Edward Burghardt W. E. B. Du Bois was an American sociologist, historian, civil rights activist, Pan-Africanist, author, writer and editor.
PDF file is 530 pages
Bois noir epidemiology and management
No full textBOIS NOIR EPIDEMIOLOGY
Bois noir (BN) is the most important disease of the phytoplasma-associated grapevine yellows (GY) complex, causing important economic losses in all major wine-growing areas by reducing fruit quality and yields. BN has been associated with ‘Candidatus Phytoplasma solani’ (CaPsol, subgroup 16SrXIIA or stolbur group) (Quaglino et al., 2013). The main insect vector of CaPsol is the planthopper Hyalesthes obsoletus Signoret (Maixner, 1994), erratically transmitting CaPsol to grapevine and living
preferentially on stinging nettle, bindweed and other herbaceous plants and shrubs present in the vineyard and surrounding areas (Mori et al., 2020). Molecular approaches along with transmission trials unveiled that other polyphagous insect species can play a role in vectoring CaPsol to grapevine, including Reptalus panzeri Löw, Aphrodes makarovi Zachvatkin and Dicranotropis remaniaca Guglielmino (Quaglino et al., 2019). In addition, Reptalus artemisiae (Becker), Macrosteles quadripunctulatus (Kirschbaum), Anaceratagallia ribauti (Ossiannilsson), and Pentastiridius leporinus (L.) were also identified as putative CaPsol insect vectors, still lacking defined epidemiological role. Moreover, many other weedy hosts were found infected by CaPsol, showing the
existence of several reservoir plants in the different agroecosystems (Chuche et al., 2018). The multifaceted ecology of BN highlighted the great genetic diversity and adaptability of CaPsol phytoplasma.
BOIS NOIR MANAGEMENT
The complex epidemiology of BN, involving several insect vector species transmitting CaPsol from multiple plant hosts to grapevine, makes very difficult the disease containment in vineyards. Sustainable Bois noir management is based on grapevines and insect vectors strategies.
Bois noir management strategies focused on grapevine
The selection of healthy propagating material and the choice of grapevine varieties showing low susceptibility to the pathogen, can play a key role in the prevention of BN. To eliminate phytoplasma from infected mother plants, hot water treatments, cryotherapy, and tissue cultures were used, underlying the possible and promising applications of such methodologies on a large scale (Pierro et al., 2024). Nevertheless, after the introduction of phytoplasma-free planting materials in vineyards, the presence of insect vectors able to transfer phytoplasma into healthy plants still represents a concrete risk, thus the BN management strategy needs to be implemented by multiple management approaches. About curative strategies, the utilization of agronomical practices (partial uprooting and pulling of symptomatic plants, grafting of materials from recovered vines to symptomatic plants) and the treatments of the canopy of BN-affected grapevines with resistance inducers or biostimulants showed promising results in inducing recovery and increasing berry production in some grapevine cultivars.
The application of these strategies should be extended to wider geographic areas and grapevine varieties to have further confirmation of their effectiveness, optimizing the formulations of resistance inducers, and clarifying the involved mechanism of actions.
Bois noir management strategies focused on insect vectors
Since H. obsoletus (and many other BN insect vectors) is a polyphagous species, whose life cycle is not restricted in the vineyard, but also involves mainly surrounding areas, hedges and forests, the use of insecticides cannot significantly reduce neither the vector population, nor BN incidence (Mori et al., 2008). For the control of H. obsoletus on herbaceous plant hosts, chemical weeding, soil tilling, and frequent cuts were proposed (Mori et al., 2016); however, it should be considered that weed management may produce a relocation of insects, including those transmitting CaPsol, from wild
species to grapevine obtaining a fast and significant raising of BN incidence in vineyards.
Alternatively, in organic vineyards, programmed cuts until late summer are highly needed to promote the development of perennial grasses, competitive with stinging nettle (Maixner et al., 2010). Novel and sustainable vector control strategies have been recently developed such as the application of the biocontrol agents (entomopathogenic fungi and nematodes) against H. obsoletus (Moussa et al., 2021) and the microbial resource management (endosymbionts) in insect vectors (Gonella et al., 2011). In
some area the use of chaste tree in the vineyard surroundings as a trap plant for H. obsoletus to prevent BN spreading in the vineyard was suggested (Sharon et al., 2005).
Considering that BN epidemiology involves multiple plant hosts and several insect vectors, the disease management should include an integrated approach based on the direct and indirect vectors control and the use of resistant grapevines
41X Peter de Bois: vitale stad 2009-2014
No full textIn 41x Peter de Bois / Vitale Stad 2009- 2014 worden 41 columns van Peter de Bois gepubliceerd. Deze zijn verschenen vanuit zijn rol als hoofdredacteur van Vitale Stad. Dit vakblad biedt hoogwaardige en onafhankelijke kennis over de stad en beschrijft wat er gebeurt op het snijvlak van fysiek en sociaal. Vitale Stad duidt niet alleen de problemen, maar zoekt nadrukkelijk naar de oplossingen. Dit boek vormt een naslagwerk en inspiratiebron voor professionals die zich bezighouden met stedelijke vernieuwing en leefbaarheid. De inhoud speelt in op de sociale, fysieke én economische vraagstukken waar onze steden mee kampe
"Soft" and "Hard" Policy Measures for Young People
No full textAcross Europe there is an increasing consensus that individuals need to become more active in their
own social integration process. Participation in Transition focuses on young people’s motivation in their
transitions from education to work. Through an analysis of case studies the book provides empirical
insight into the transition experiences of young people and examines how different types of transition
policies affect motivation. The key objective is to examine whether and under what conditions the
principle of active participation is effective in re-motivating disengaged young people and argues that
mainstream approaches to activation remain ineffective as they neglect young people’s subjective
realities. The book adopts an innovative interdisciplinary approach that combines discrete research
and policy perspectives on the labour market, youth and citizenship as well as learning and motivation.
The study has been carried out in the framework of the European Group for Integrated Social
Research (EGRIS).
Contents: A. Walther/M. du Bois-Reymond/A. Biggart: Learning, Motivation and Participation in Youth
Transitions: theoretical perspectives · A. Walther: Regulating Youth Transitions: trends, dilemmas and
variations across different ‘regimes’ in Europe · T. Bechmann Jensen/B. Stauber: Researching Motivation
and Participation in Youth Transitions in a Comparative Perspective · M. Cuconato/A. Hayes/G. Lenzi/
A. Walther: ‘Soft’ and ‘Hard’ Policy Measures for Young People · W. Plug/M. du Bois-Reymond: Transition
Patterns between Structure and Agency · B. Stauber/A. Walther: Motivational Careers in Transition:
expectations, experiences, and changes · B. Stauber/A. Holmboe/T. Bechmann Jensen/G. Lenzi/C. Laasch/
P. Leahy/A. López Blasco/W. Plug/H. Seifert: Experiences of Self-determination. Case studies into
biographical effects of participatory practice · A. Pohl/M. du Bois-Reymond/P. Burgess/A. Holmboe/
A. Hayes/L. Iacob/J. Machado Pais/O. Marcovici/M. Santos: Learning Biographies. Case studies into
dimensions and prerequisites of competence development · A. Walther/A. Pohl/P. Burgess: Potentials
of Participation for Citizenship and Social Inclusio
Le bois, un matériau hygroscopique
No full textInternational audienceLe bois est un matériau hygroscopique : sa teneur en eau dépend de l’humidité relative du milieu dans lequel il baigne. On appelle taux d’humidité du bois la masse d’eau de l’échantillon rapportée à sa masse anhydre, exprimée en pourcentage. Ce taux d’humidité peut dépasser 100 % : un échantillon de bois pesant 25 g humide, qui ne pèse plus que 10 g anhydre, présente un taux d’humidité de 1,5, soit 150 % [(25-10)/10]. Dans l’arbre, le bois est gorgé de liquide, son taux d’humidité est élevé. À la suite de l’abattage de l’arbre, le bois va s’équilibrer avec le milieu environnant, notamment par l’intermédiaire de la nouvelle surface créée: on parle de séchage. Une partie de l’eau contenue dans le matériau est dite « libre », elle disparaît lors du séchage, sans modification dimensionnelle. En dessous d’un certain taux d’humidité – appelé point de saturation des fibres (PSF), qui dépend de l’essence de bois concernée et qui est notamment lié à sa composition chimique –, l’eau éliminée par évacuation s’accompagnera d’un retrait dimensionnel. Ce retrait est très fortement anisotrope, il dépend de la direction du matériau considérée
La mystique du confucianisme : le saint
No full textBois G. La mystique du confucianisme : le saint. In: Revue d'histoire et de philosophie religieuses, 10e année n°4-5, Juillet-octobre 1930. pp. 448-466
Appréciation professionnelle de la qualité de l'aspect des débits du bois de chêne en fonction des caractères
No full textRapport de contrat de recherche *INRA, Unité Croissance, Production, Qualité des Bois, Equipe de Recherches sur la Qualité des Bois, 54280 Champenoux, France Diffusion du document : INRA, Unité Croissance, Production, Qualité des Bois, Equipe de Recherches sur la Qualité des Bois, 54280 Champenoux, Franc
A travers bois : morceau caractéristique pour piano : op. 44 / par G. Becker
No full textTitre uniforme : Becker, G. (18..-19.. ; compositeur). Compositeur. [À travers bois. Piano. Op. 44]Piano, Musique de -- +* 1800......- 1899......+:19e siècle
NUMERICAL AND EXPERIMENTAL INVESTIGATIONS IN A VANED DIFFUSER OF SHF IMPELLER: FLUID LEAKAGE EFFECT
No full textThe paper presents the analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV technique, pressure probe traverses and numerical simulations. PIV measurements have been performed at different heights inside one diffuser channel passage for a given speed of rotation and various flow rates. For each operating condition, PIV measurements have been made for different angular positions of the impeller. For each angular position, instantaneous velocities charts have been obtained on two simultaneous views, which allows, firstly, to cover the space between the leading edge of the impeller and the diffuser throat and secondly, to get a rather good evaluation of phase averaged velocity charts and “fluctuating rates “. Probe traverses have also been performed using a 3 holes pressure probe from hub to shroud diffuser width at different radial locations in between the two diffuser geometrical throats. The numerical simulations were realized with the two commercial codes: i-Star CCM+ 7.02.011 (at LML), ii-CFX 10.0 (at University of Padova). Fully unsteady calculations of the whole pump were performed. Comparisons between numerical and experimental results are presented and discussed for two flow rates. In this respect, the effects of fluid leakage due to the gap between the rotating and fixed part of the pump model are analysed and discussed
- …
