Labour Supply, Work Effort and Contract Choice: Theory and Evidence on Physicians

We develop and estimate a generalized labour supply model that incorporates work effort into the standard consumption-leisure trade-off. We allow workers a choice between two contracts: a piece rate contract, wherein he is paid per unit of service provided, and a mixed contract, wherein he receives an hourly wage and a reduced piece rate. This setting gives rise to a non-convex budget set and an efficient budget constraint (the upper envelope of contract-specific budget sets). We apply our model to data collected on specialist physicians working in the Province of Quebec (Canada). Our data set contains information on each physician's labour supply and their work effort (clinical services provided per hour worked). It also covers a period of policy reform under which physicians could choose between two compensation systems: the traditional fee-for-service, under which physicians receive a fee for each service provided, and mixed remuneration, under which physicians receive a per diem as well as a reduced fee-for-service. We estimate the model using a discrete choice approach. We use our estimates to simulate elasticities and the effects of ex ante reforms on physician contracts. Our results show that physician services and effort are much more sensitive to contractual changes than is their time spent at work. Our results also suggest that a mandatory reform, forcing all physicians to adopt the mixed remuneration system, would have had substantially larger effects on physician behaviour than those observed under the voluntary reform.labour supply, effort, contracts, practice patterns of physicians, discrete choice econometric models, mixed logit

Modeling atrial arrhythmias : impact on clinical diagnosis and therapies

Atrial arrhythmias are the most frequent sustained rhythm disorders in humans and often lead to severe complications such as heart failure and stroke. Despite the important insights provided by animal models into the mechanisms of atrial arrhythmias, direct translation of experimental findings to new therapies in patients has not been straightforward. With the advances in computer technology, large-scale electroanatomical computer models of the atria that integrate information from the molecular to organ scale have reached a level of sophistication that they can be used to interpret the outcome of experimental and clinical studies and aid in the rational design of therapies. This paper reviews the state-of-the-art of computer models of the electrical dynamics of the atria and discusses the evolving role of simulation in assisting the clinical diagnosis and treatment of atrial arrhythmias

Physicians’ Multitasking and Incentives: Empirical Evidence from a Natural Experiment

We analyse how physicians respond to contractual changes and incentives within a multitasking environment. In 1999 the Quebec government (Canada) introduced an optional mixed compensation (MC) system, combining a fixed per diem with a partial (relative to the traditional fee-for-service system) fee for services provided. We combine panel survey and administrative data on Quebec physicians to evaluate the impact of this change in incentives on their practice choices. We highlight the differentiated impact of incentives on various dimensions of physician behaviour by considering a wide range of labour supply variables: time spent on seeing patients, time devoted to teaching, administrative tasks or research, as well as the volume of clinical services and average time per clinical service. Our results show that, on average, the reform induced physicians who changed from FFS to MC to reduce their volume of (billable) services by 6.15% and to reduce their hours of work spent on seeing patients by 2.57%. Their average time spent per service increased by 3.81%, suggesting a potential quality-quantity substitution. Also the reform induced these physicians to increase their time spent on teaching and administrative duties (tasks not remunerated under the fee-for-service system) by 7.9%. En 1999, le ministère de la Santé et des Services Sociaux du Québec introduisait un mode de rémunération mixte optionnel pour rémunérer l’activité hospitalière des médecins spécialistes. Ce mode combine une rémunération forfaitaire pour chaque jour de travail (per diem ou demi per diem) et une rémunération partielle à l’acte s’exprimant en un pourcentage du tarif habituellement applicable pour un service donné. Cette étude jumelle en panel des données de sondage du Collège des Médecins du Québec et des données administratives de la Régie de l’assurance maladie du Québec pour évaluer l’impact de ce mode de rémunération sur les choix de pratique des spécialistes. Nous mettons l’accent sur l’effet de la rémunération mixte sur plusieurs dimensions du comportement professionnel du médecin : heures consacrées aux patients, heures consacrées à l’enseignement, aux activités médicales administratives et à la recherche, volume de services médicaux et temps moyen par service médical. Nos résultats montrent que l’introduction de la rémunération mixte a incité les médecins qui sont passés de la rémunération à l’acte à la rémunération mixte à réduire leur nombre de services médicaux (facturables) de 6,15 % et à réduire leurs heures de travail consacrées aux patients de 2,57 %. En revanche, le temps moyen par service médical s’est accru de 3,81 %, ce qui peut suggérer une substitution entre la quantité et la qualité des services. La réforme a aussi incité ces médecins à accroître le temps consacré à l’enseignement et aux activités médicales administratives (activités non rémunérées par la rémunération à l’acte) de 7,9 %. En outre, le temps consacré par ces médecins à la recherche (activité non rémunérée par l’un ou l’autre des modes de rémunération) a diminué de 14,7 %. Enfin, le revenu des médecins qui sont passés à la rémunération mixte s’est accru de 8,05 %, indiquant qu’il était financièrement rentable pour ceux-ci de choisir ce mode de rémunération.physician payment mechanisms, multitasking, mixed-payment systems, incentive contracts, labour supply, self-selection, panel estimation., mécanismes de rémunération des médecins, fonctionnement multitâche, rémunération mixte, contrats incitatifs, offre de travail, auto-sélection, estimation en panel

Effects of Electrical and Structural Remodeling on Atrial Fibrillation Maintenance: A Simulation Study

Atrial fibrillation, a common cardiac arrhythmia, often progresses unfavourably: in patients with long-term atrial fibrillation, fibrillatory episodes are typically of increased duration and frequency of occurrence relative to healthy controls. This is due to electrical, structural, and contractile remodeling processes. We investigated mechanisms of how electrical and structural remodeling contribute to perpetuation of simulated atrial fibrillation, using a mathematical model of the human atrial action potential incorporated into an anatomically realistic three-dimensional structural model of the human atria. Electrical and structural remodeling both shortened the atrial wavelength - electrical remodeling primarily through a decrease in action potential duration, while structural remodeling primarily slowed conduction. The decrease in wavelength correlates with an increase in the average duration of atrial fibrillation/flutter episodes. The dependence of reentry duration on wavelength was the same for electrical vs. structural remodeling. However, the dynamics during atrial reentry varied between electrical, structural, and combined electrical and structural remodeling in several ways, including: (i) with structural remodeling there were more occurrences of fragmented wavefronts and hence more filaments than during electrical remodeling; (ii) dominant waves anchored around different anatomical obstacles in electrical vs. structural remodeling; (iii) dominant waves were often not anchored in combined electrical and structural remodeling. We conclude that, in simulated atrial fibrillation, the wavelength dependence of reentry duration is similar for electrical and structural remodeling, despite major differences in overall dynamics, including maximal number of filaments, wave fragmentation, restitution properties, and whether dominant waves are anchored to anatomical obstacles or spiralling freely

Defining the phospho-adhesome through the phosphoproteomic analysis of integrin signalling

Cell-extracellular matrix (ECM) adhesion is a fundamental requirement for multicellular existence due to roles in positioning, proliferation and differentiation. Phosphorylation plays a major role in adhesion signalling; however, a full understanding of the phosphorylation events that occur at sites of adhesion is lacking. Here we report a proteomic and phosphoproteomic analysis of adhesion complexes isolated from cells spread on fibronectin. We identify 1,174 proteins, 499 of which are phosphorylated (1,109 phosphorylation sites), including both well-characterized and novel adhesion-regulated phosphorylation events. Immunoblotting suggests that two classes of phosphorylated residues are found at adhesion sites-those induced by adhesion and those constitutively phosphorylated but recruited in response to adhesion. Kinase prediction analysis identifies novel kinases with putative roles in adhesion signalling including CDK1, inhibition of which reduces adhesion complex formation. This phospho-adhesome data set constitutes a valuable resource to improve our understanding of the signalling mechanisms through which cell-ECM interactions control cell behaviour

A proteomic approach reveals integrin activation state-dependent control of microtubule cortical targeting

Integrin activation, which is regulated by allosteric changes in receptor conformation, enables cellular responses to the chemical, mechanical and topological features of the extracellular microenvironment. A global view of how activation state converts the molecular composition of the region proximal to integrins into functional readouts is, however, lacking. Here, using conformation-specific monoclonal antibodies, we report the isolation of integrin activation state-dependent complexes and their characterization by mass spectrometry. Quantitative comparisons, integrating network, clustering, pathway and image analyses, define multiple functional protein modules enriched in a conformation-specific manner. Notably, active integrin complexes are specifically enriched for proteins associated with microtubule-based functions. Visualization of microtubules on micropatterned surfaces and live cell imaging demonstrate that active integrins establish an environment that stabilizes microtubules at the cell periphery. These data provide a resource for the interrogation of the global molecular connections that link integrin activation to adhesion signalling

Talin mechanosensitivity is modulated by a direct interaction with cyclin-dependent kinase-1

AbstractTalin (TLN1) is a mechanosensitive component of adhesion complexes that directly couples integrins to the actin cytoskeleton. In response to force, talin undergoes switch-like behavior of its multiple rod domains that modulate interactions with its binding partners. Cyclin-dependent kinase-1 (CDK1) is a key regulator of the cell cycle, exerting its effects through synchronized phosphorylation of a large number of protein targets. CDK1 activity maintains adhesion during interphase, and its inhibition is a prerequisite for the tightly choreographed changes in cell shape and adhesion that are required for successful mitosis. Using a combination of biochemical, structural, and cell biological approaches, we demonstrate a direct interaction between talin and CDK1 that occurs at sites of integrin-mediated adhesion. Mutagenesis demonstrated that CDK1 contains a functional talin-binding LD motif, and the binding site within talin was pinpointed to helical bundle R8. Talin also contains a consensus CDK1 phosphorylation motif centered on S1589, a site shown to be phosphorylated by CDK1 in vitro. A phosphomimetic mutant of this site within talin lowered the binding affinity of the cytoskeletal adaptor KANK and weakened the response of this region to force as measured by single molecule stretching, potentially altering downstream mechanotransduction pathways. The direct binding of the master cell cycle regulator CDK1 to the primary integrin effector talin represents a coupling of cell proliferation and cell adhesion machineries and thereby indicates a mechanism by which the microenvironment can control cell division in multicellular organisms.</p

Contesting language policy for asylum seekers in the Northern periphery: The story of Tailor F

This article is about navigating asylum, employment and language policy in a new country as an asylum seeker. Through the story of one individual, we show that profound inequalities are exacerbated when forced migrants are limited in their choice of language they might study or use. The individual is Tailor F, an Iraqi man seeking asylum, and the country is Finland, officially bilingual, with a majority language (Finnish) and a minority language (Swedish). Finland’s official bilingualism does not extend evenly to language education provided for asylum seekers, who are taught Finnish regardless of the region where they are placed. Upon arrival, Tailor F was housed in a reception centre for asylum seekers located in a Swedish-dominant rural area of the country. Through our linguistic ethnography we examine how he navigates multilingually in his early settlement, his current work and his online life. We relate his story to explicit and implicit official bilingualism in Finland and discuss his lived experiences in relation to the contexts of asylum policy and employment. Tailor F’s story shows how, through his practices, he has contested implicit language policy for asylum seekers in order to gain membership of the local Swedish-dominant community, achieve a sense of belonging, and potentially realise his aspirations for the future

Talin rod domain-containing protein 1 (TLNRD1) is a novel actin-bundling protein which promotes filopodia formation

Talin is a mechanosensitive adapter protein that couples integrins to the cytoskeleton. Talin rod domain-containing protein 1 (TLNRD1) shares 22% homology with the talin R7R8 rod domains, and is highly conserved throughout vertebrate evolution, although little is known about its function. Here we show that TLNRD1 is an α-helical protein structurally homologous to talin R7R8. Like talin R7R8, TLNRD1 binds F-actin, but because it forms a novel antiparallel dimer, it also bundles F-actin. In addition, it binds the same LD motif-containing proteins, RIAM and KANK, as talin R7R8. In cells, TLNRD1 localizes to actin bundles as well as to filopodia. Increasing TLNRD1 expression enhances filopodia formation and cell migration on 2D substrates, while TLNRD1 down-regulation has the opposite effect. Together, our results suggest that TLNRD1 has retained the diverse interactions of talin R7R8, but has developed distinct functionality as an actin-bundling protein that promotes filopodia assembly