125 research outputs found
Lâentrepreneuriat social au QuĂ©bec. Lâexemple des centres de formation en entreprise et rĂ©cupĂ©ration
Lâentrepreneuriat social au QuĂ©bec a Ă©tĂ© peu Ă©tudiĂ© jusquâici. Pourtant, il recĂšle des comportements spĂ©cifiques liĂ©s tant aux paradigmes entrepreneuriaux traditionnels quâaux intĂ©rĂȘts des intervenants sociaux. Par exemple, les Centres de formation en entreprise et rĂ©cupĂ©ration (CFER), qui ont vu le jour dans une vingtaine de rĂ©gions au QuĂ©bec, offrent aux dĂ©crocheurs de seize Ă dix-huit ans une dĂ©marche dâapprentissage particuliĂšre, Ă partir dâune insertion partielle dans une entreprise de rĂ©cupĂ©ration mise sur pied et gĂ©rĂ©e par une Ă©quipe de professeurs-superviseurs. Ces Centres cherchent aussi Ă dĂ©velopper une entreprise rentable tout en permettant aux professeurs dâassurer la formation au travail de leurs Ă©tudiants plutĂŽt que de dĂ©lĂ©guer cette responsabilitĂ© Ă diverses entreprises par le biais de stages. La mise sur pied de ces entreprises suppose dâavoir dĂ©celĂ© une opportunitĂ© pour pouvoir assurer leur viabilitĂ©, une Ă©quipe entrepreneuriale avec un leader, informel ou non, et diverses ressources dâappoint Ă court et Ă long terme apportĂ©es par le milieu. De mĂȘme, elle a besoin de lâenthousiasme des professeurs et de lâappui de la commission scolaire sinon de quelques mĂ©cĂšnes de la rĂ©gion. LâexpĂ©rience de six CFER analysĂ©s montre que celle-ci nâest pas nĂ©cessairement facile, mais donne des rĂ©sultats importants tant Ă propos de la persĂ©vĂ©rance des Ă©tudiants que de leur placement par la suite dans des entreprises, sans compter les effets bĂ©nĂ©fiques sur la rĂ©cupĂ©ration de diverses matiĂšres et ainsi sur lâenvironnement.Thus far, little research has focused on social entrepreneurship in Quebec. Yet it involves specific behaviours related both to traditional entrepreneurial paradigms and to the interests of social actors. For example, the, Centres de formation en entreprise et rĂ©cupĂ©ration â CFERs (enterprise and recycling training centres), which have been created in some twenty regions of Quebec, offer dropouts aged sixteen to eighteen a specific learning process, based on partial placement in a recycling enterprise set up and managed by a team of teacher-supervisors. These Centres also seek to develop a profitable business, while enabling the teachers to provide work training to their students, rather than delegating this responsibility to various firms via traineeships. The setting up of these enterprises presupposes the identification of an opportunity to ensure their viability, an entrepreneurial team with a leader, whether informal or otherwise, and various ancillary resources provided by the community over the short to medium term. It also needs the enthusiasm of the teachers and the support of the school board, or else that of a few local sponsors. The experience of the six CFERs analysed shows that this is not necessarily easy, but gives important results in terms of the studentsâ perseverance, and of their subsequent placement in enterprises, not to mention the beneficial effects in terms of the recycling of various materials and on the environment
Pooling problem: Alternate formulations and solution methods
Copyright @ 2004 INFORMSThe pooling problem, which is fundamental to the petroleum industry, describes a situation in which products possessing different attribute qualities are mixed in a series of pools in such a way that the attribute qualities of the blended products of the end pools must satisfy given requirements. It is well known that the pooling problem can be modeled through bilinear and nonconvex quadratic programming. In this paper, we investigate how best to apply a new branch-and-cut quadratic programming algorithm to solve the pooling problem. To this effect, we consider two standard models: One is based primarily on flow variables, and the other relies on the proportion. of flows entering pools. A hybrid of these two models is proposed for general pooling problems. Comparison of the computational properties of flow and proportion models is made on several problem instances taken from the literature. Moreover, a simple alternating procedure and a variable neighborhood search heuristic are developed to solve large instances and compared with the well-known method of successive linear programming. Solution of difficult test problems from the literature is substantially accelerated, and larger ones are solved exactly or approximately.This project was funded by Ultramar Canada and Luc MassĂ©. The work of C. Audet was supported by NSERC (Natural Sciences and Engineering Research Council) fellowship PDF-207432-1998 and by CRPC (Center for Research on Parallel Computation). The work of J. Brimberg was supported by NSERC grant #OGP205041. The work of P. Hansen was supported by FCAR(Fonds pour la Formation des Chercheurs et lâAide Ă la Recherche)
grant #95ER1048, and NSERC grant #GP0105574
Phosphidoboratabenzene-Rhodium(I) complexes as precatalysts for the hydrogenation of alkenes at room temperature and atmospheric pressure
The di-tert-butylphosphido-boratabenzene ligand (DTBB) reacts with [(C2H4)2RhCl]2 yielding the dimeric
species [(C2H4)Rh(DTBB)]2 (1). This species was fully characterized by multinuclear NMR and X-ray crystallography.
Complex 1 readily dissociates ethylene in solution and upon exposure to 1 atm of H2 is capable
of carrying out the hydrogenation of ethylene. The characterization of two RhâH species by multinuclear
NMR spectroscopy is provided. The reactivity of 1 towards the catalytic hydrogenation of alkenes and
alkynes at room temperature and 1 atm of H2 is reported and compared to the activity of Wilkinsonâs catalyst
under the same reaction conditions
Les campagnes pour le 15$/h aux Ătats-Unis et le processus de revitalisation syndicale
Les diffĂ©rentes campagnes pour le 15/h aux Ătats-Unis favorisent la revitalisation syndicale, c'est-Ă -dire favorisent l'accumulation de pouvoir par les organisations syndicales et le dĂ©ploiement de stratĂ©gies inspirĂ©es du syndicalisme de mouvement social. Ce mĂ©moire prĂ©sente d'abord le contexte de l'adoption de la revendication d'un salaire minimum et d'un salaire dĂ©cent par les organisations syndicales amĂ©ricaines au dĂ©but du 20e siĂšcle puis l'historique de l'Ă©volution du salaire minimum fĂ©dĂ©ral jusqu'Ă nos jours. Concernant les campagnes pour le 15/h, est analysĂ©e plus en profondeur. Il semble que ces campagnes, qui prennent souvent la forme d'authentiques mouvements sociaux, participent effectivement Ă la revitalisation syndicale. Cependant, malgrĂ© les victoires Ă©conomiques importantes, les organisationsions syndicales amĂ©ricaines ont eu peu de succĂšs Ă transcrire ces mouvements en pouvoir institutionnel durable capable de renverser la tendance lourde au dĂ©clin syndical qui persiste depuis la dĂ©cennie 1980
[(IMes)2Pt(H)(ClBC5H4SiMe3)] : a BorabenzeneâPlatinum Adduct with an Unusual PtâClâB Interaction
A PtâClâB interaction is observed when a borabenzene derivative reacts with a platinum(0) precursor with bulky Nâheterocyclic carbene ligands. The resulting platinum(II) complex (see picture; Ptâ
red, Nâ
blue, Clâ
green, Bâ
pink, Siâ
yellow) involves a new bonding mode for borabenzene, which usually binds in an η6 fashion to transition metals
Magnetic resonance imaging of human tissue-engineered adipose substitutes
Adipose tissue (AT) substitutes are being developed to answer the strong demand in reconstructive surgery. To facilitate the validation of their functional performance in vivo, and to avoid resorting to excessive number of animals, it is crucial at this stage to develop biomedical imaging methodologies, enabling the follow-up of reconstructed AT substitutes. Until now, biomedical imaging of AT substitutes has scarcely been reported in the literature. Therefore, the optimal parameters enabling good resolution, appropriate contrast, and graft delineation, as well as blood perfusion validation, must be studied and reported. In this study, human adipose substitutes produced from adipose-derived stem/stromal cells using the self-assembly approach of tissue engineering were implanted into athymic mice. The fate of the reconstructed AT substitutes implanted in vivo was successfully followed by magnetic resonance imaging (MRI), which is the imaging modality of choice for visualizing soft ATs. T1-weighted images allowed clear delineation of the grafts, followed by volume integration. The magnetic resonance (MR) signal of reconstructed AT was studied in vitro by proton nuclear magnetic resonance (1H-NMR). This confirmed the presence of a strong triglyceride peak of short longitudinal proton relaxation time (T1) values (200±53âms) in reconstructed AT substitutes (total T1=813±76âms), which establishes a clear signal difference between adjacent muscle, connective tissue, and native fat (total T1 âŒ300âms). Graft volume retention was followed up to 6 weeks after implantation, revealing a gradual resorption rate averaging at 44% of initial substitute's volume. In addition, vascular perfusion measured by dynamic contrast-enhanced-MRI confirmed the graft's vascularization postimplantation (14 and 21 days after grafting). Histological analysis of the grafted tissues revealed the persistence of numerous adipocytes without evidence of cysts or tissue necrosis. This study describes the in vivo grafting of human adipose substitutes devoid of exogenous matrix components, and for the first time, the optimal parameters necessary to achieve efficient MRI visualization of grafted tissue-engineered adipose substitutes
Under ice spills of conventional crude oil and diluted bitumen: Physiological resilience of the blue mussel and transgenerational effects
Spillages at sea of diluted bitumen (dilbit) from oil sands have received little attention until now. To our best knowledge, there are no reports on the impact of a severe exposure to dilbit on the Blue mussel (Mytilus edulis). In this study, adult Blue mussels were exposed to one conventional crude oil (Heidrun) and two dilbits (Cold Lake Blend and Access Western Blend) for a period of 7 days in an ice-covered environment and then maintained for three months until the spawning season. The exposed mussels were monitored for aromatic hydrocarbon bioaccumulation, physiological energetic budget, cellular stress, byssus production and gametogenesis. In spring, spawning was induced to characterize breeding success. Bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) was detected after three days of exposure, with higher concentrations of PAHs associated to the conventional oil (5.49 ± 0.12 ÎŒg·gâ1 d.w.) compared to both dilbits (0.91 ± 0.02 ÎŒg·gâ1; 0.51 ± 0.03 ÎŒg·gâ1 d.w.). Despite a fast depuration rate and a good resilience of the exposed mussels, significant negative effects were observed at the cellular, physiological and fitness levels, especially in offspring. Our results suggest a higher toxicity of the diluted bitumen compared to the conventional crude despite the lower bioaccumulation of total PAHs. Dilbit treatments caused evident negative transgenerational effects on unexposed F1 generation. -- Keywords : Diluted bitumen ; PAHs ; Blue mussel ; Winter oil spill ; Ice oil spill
Ablation of Proliferating Cells in the CNS Exacerbates Motor Neuron Disease Caused by Mutant Superoxide Dismutase
Proliferation of glia and immune cells is a common pathological feature of many neurodegenerative diseases including amyotrophic lateral sclerosis (ALS). Here, to investigate the role of proliferating cells in motor neuron disease, SOD1G93A transgenic mice were treated intracerebroventicularly (ICV) with the anti-mitotic drug cytosine arabinoside (Ara-C). ICV delivery of Ara-C accelerated disease progression in SOD1G93A mouse model of ALS. Ara-C treatment caused substantial decreases in the number of microglia, NG2+ progenitors, Olig2+ cells and CD3+ T cells in the lumbar spinal cord of symptomatic SOD1G93A transgenic mice. Exacerbation of disease was also associated with significant alterations in the expression inflammatory molecules IL-1ÎČ, IL-6, TGF-ÎČ and the growth factor IGF-1
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