JD-R model in entrepreneurship : the impacts of job demands and resources on well-being and performance

Le modèle des demandes et ressources (JD-R) est largement utilisé pour comprendre comment promouvoir le bien-être et la performance des employés pour un large éventail de professions. Malgré de nombreuses études basées sur le JD-R, nous en savons relativement peu sur les entrepreneurs. Ainsi, l'objectif de cette thèse est d'évaluer l'impact de certaines caractéristiques du travail (c.-à-d., demandes et ressources au travail) sur la santé psychologique (c.-à-d., épuisement professionnel et engagement au travail) et la performance des entrepreneurs. Au total, une étude pilote, une étude longitudinale réalisée pendant la pandémie de COVID-19 et une étude comparative entre entrepreneurs et employés démontrent que les demandes au travail élevées (c.-à-d., surcharge, ambiguïté et conflit de rôle) épuisent les employés mentalement et physiquement, entraînant ainsi un épuisement énergétique et des problèmes de santé (c.-à-d., l'épuisement professionnel). En revanche, les ressources au travail (c.-à-d., l'autonomie, l'adaptabilité et la proactivité) se sont avérées favoriser l'engagement et la performance. Alternativement, les résultats suggèrent que les demandes et ressources au travail réduisent respectivement l'engagement et l'épuisement professionnel. Cependant, aucune interaction entre les demandes et ressources au travail n'a été trouvée. Une comparaison entre entrepreneurs et employés a également révélé que la relation entre les ressources au travail et l'engagement est moins importante pour les entrepreneurs que pour les employés. Ce projet de recherche démontre l'applicabilité et la transférabilité du modèle JD-R aux entrepreneurs et permet de mettre en évidence les différences entre cette population et les employés.The Job Demands-Resources model (JD-R) is widely used to understand how to promote employee well-being and performance across a broad range of occupations. Despite many findings based on the JD-R, we know comparatively few about entrepreneurs. Thus, the objective of this thesis is to evaluate the impact of certain work characteristics (i.e., job demands and resources) on entrepreneurs’ well-being (i.e., burnout and work engagement) and performance. Altogether, a pilot study, a longitudinal study made during the COVID-19 pandemic, and a comparative study between entrepreneurs and employees showed that high job demands (i.e. role overload, role ambiguity, and role conflict) exhaust entrepreneurs mentally and physically, therefore leading to energy depletion and health problems (i.e. burnout). In contrast, job resources (i.e. autonomy, adaptivity, and proactivity) were found to foster engagement and performance. Alternatively, results suggest that job demands and resources respectively reduce engagement and burnout. However, no interactions between job demands and resources were found. A comparison between entrepreneurs and employees also revealed that the relation between job resources and engagement is more important for employees than for entrepreneurs. This research project demonstrates the applicability and transferability of the JD- R model to entrepreneurs and helps highlight differences between this population and employees

Analysis of the capacity of google trends to measure interest in conservation topics and the role of online news

With the continuous growth of internet usage, Google Trends has emerged as a source of information to investigate how social trends evolve over time. Knowing how the level of interest in conservation topics--approximated using Google search volume--varies over time can help support targeted conservation science communication. However, the evolution of search volume over time and the mechanisms that drive peaks in searches are poorly understood. We conducted time series analyses on Google search data from 2004 to 2013 to investigate: (i) whether interests in selected conservation topics have declined and (ii) the effect of news reporting and academic publishing on search volume. Although trends were sensitive to the term used as benchmark, we did not find that public interest towards conservation topics such as climate change, ecosystem services, deforestation, orangutan, invasive species and habitat loss was declining. We found, however, a robust downward trend for endangered species and an upward trend for ecosystem services. The quantity of news articles was related to patterns in Google search volume, whereas the number of research articles was not a good predictor but lagged behind Google search volume, indicating the role of news in the transfer of conservation science to the public

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

A Distinct Role of the Autonomic Nervous System in Modulating the Function of Lymphatic Vessels under Physiological and Tumor-Draining Conditions

Lymphatic vessels (LVs) are important in the regulation of tissue fluid homeostasis and the pathogenesis of tumor progression. We investigated the innervation of LVs and the response to agonists and antagonists of the autonomic nervous system in vivo. While skin-draining collecting LVs express muscarinic, α- and β-adrenergic receptors on lymphatic endothelial cells and smooth muscle cells, intestinal lacteals express only β-adrenergic receptors and muscarinic receptors on their smooth muscle cells. Quantitative in vivo near-infrared imaging of the exposed flank-collecting LV revealed that muscarinic and α-adrenergic agonists increased LV contractility, whereas activation of β-adrenergic receptors inhibited contractility and initiated nitric oxide (NO)-dependent vasodilation. Tumor-draining LVs were expanded and showed a higher innervation density and contractility that was reduced by treatment with atropine, phentolamine, and, most potently, isoproterenol. These findings likely have clinical implications given the impact of lymphatic fluid drainage on intratumoral fluid pressure and thus drug delivery

MAIT cells are activated in acute Dengue virus infection and after <i>in vitro</i> Zika virus infection

<div><p>Dengue virus (DENV) and Zika virus (ZIKV) are members of the <i>Flaviviridae</i> and are predominantly transmitted via mosquito bites. Both viruses are responsible for a growing number of infections in tropical and subtropical regions. DENV infection can cause lethargy with severe morbidity and dengue shock syndrome leading to death in some cases. ZIKV is now linked with Guillain-Barré syndrome and fetal malformations including microcephaly and developmental disorders (congenital Zika syndrome). The protective and pathogenic roles played by the immune response in these infections is unknown. Mucosal-associated invariant T (MAIT) cells are a population of innate T cells with potent anti-bacterial activity. MAIT cells have also been postulated to play a role in the immune response to viral infections. In this study, we evaluated MAIT cell frequency, phenotype, and function in samples from subjects with acute and convalescent DENV infection. We found that in acute DENV infection, MAIT cells had elevated co-expression of the activation markers CD38 and HLA-DR and had a poor IFNγ response following bacterial stimulation. Furthermore, we found that MAIT cells can produce IFNγ in response to <i>in vitro</i> infection with ZIKV. This MAIT cell response was independent of MR1, but dependent on IL-12 and IL-18. Our results suggest that MAIT cells may play an important role in the immune response to <i>Flavivirus</i> infections.</p></div

MAIT cells have elevated expression of activation markers in acute DENV infection.

<p>Gating strategy and representative flow plots of MAIT cell frequency (A). MAIT cell frequency in acute and convalescent DENV infection (n = 25, B). MAIT cell count, (as determined by multiplying the lymphocyte count by the frequency of MAIT cells in lymphocytes), in acute and convalescent DENV infection (n = 24, C). Co-expression of CD38 and HLA-DR by MAIT cells in acute and convalescent DENV infection (n = 15, D). CD127 expression (MFI) by MAIT cells in acute and convalescent DENV infection (n = 15, E). PD-1 expression by MAIT cells in acute and convalescent DENV infection (n = 15, F). CCR6 expression (MFI) by MAIT cells in acute and convalescent DENV infection (n = 15, G). ** indicates p < 0.01, and *** indicates p < 0.001.</p

Lower IFNγ production following <i>in vitro</i> stimulation with <i>E</i>. <i>coli</i> by MAIT cells in acute DENV infection.

<p>MAIT cells were stimulated with fixed <i>E</i>. <i>coli</i> (multiplicity of exposure 10) for 24h and IFNγ production by MAIT cells was evaluated by flow cytometry. Representative flow plots of IFNγ production by MAIT cells (A). IFNγ production by MAIT cells in response to <i>E</i>. <i>coli</i> stimulation in acute and convalescent DENV infection (n = 15, B). Association between the levels of sCD14 and MAIT cells IFNγ response to <i>E</i>. <i>coli</i> stimulation in acute DENV infection (C). * indicates p < 0.05.</p

MAIT cells response to <i>in vitro</i> ZIKV infection is dependent on IL-12 and IL-18.

<p>PBMCs were infected with ZIKV (MOI: 5) for 24h and IFNγ production by MAIT cells was evaluated by flow cytometry. Representative flow plots of IFNγ production by MAIT cells (A). MAIT cells IFNγ response to ZIKV infection (n = 9, B). PBMCs were incubated in presence of MR1 (n = 6), IL-12 (n = 4), IL-18 (n = 8), and IL-12 + IL-18 (n = 4) blocking antibodies and stimulated with <i>E</i>. <i>coli</i>, ZIKV, or heat inactivated ZIKV (n = 4) and IFNγ production by MAIT cells was measured (C). The results are presented as relative production of IFNγ by MAIT cells compared to the condition without any blocking antibody. Statistical analysis was performed before data normalization. PBMCs from HIV-1- (n = 8) and HIV-1+ (n = 6) subjects were infected with ZIKV (MOI: 5) and IFNγ production by MAIT cell was evaluated (D). PBMCs from HIV-1- (n = 6) and HIV-1+ (n = 6) subjects were treated with IL-12 and IL-18 (both at 50ng/ml) for 24 hours and IFNγ production by MAIT cell was evaluated (E). The bars and whiskers represent the median and interquartile range respectively. * indicates p < 0.05 and ** indicates p < 0.01.</p

Increased levels of sCD14 in acute DENV infection.

<p>Plasma levels of sCD14 (A) and IL-7 (B) in acute and convalescent DENV infection were determined for subjects 1–10 (n = 10) and for healthy control (n = 5). The bars and whiskers represent the median and interquartile range respectively. ** indicates p < 0.01.</p

DENV patient demographics and cell count.

<p>DENV patient demographics and cell count.</p