Hematopoietic stem cells, overview and pathways implied on their self-renewal mechanisms

Blood tissue is composed approximately in 45% by cells and its derivatives, with a life span of around 120 days for erythrocytes and 3 years for certain type of lymphocytes. This lost is compensated with the hematopoietic system activity and the presence of an immature primitive cell population known as Hematopoietic Stem Cells (HSCs) which perform the hematopoiesis, a process that is active from the beginning of the fetal life and produces near to 2 x 1011 eritrocytes and 1010 white blood cells per day (1). Hematopoietic Stem Cells are capable of both self-renewal and differentiation into multiple lineages, are located in a particular niche and are identified by their own cell surface markers, as the CD34 antigen. Recently it has been possible to advance in the understanding of self-renewal, differentiation and proliferation processes and in the involvement of the signaling pathways Hedgehog, Notch and Wnt. Studying the influence of these mechanisms on in vivo and in vitro behavior and the basic biology of HSCs, has given valuable tools for the generation of alternative therapies for hematologic disorders as leukemias.

Del viajero al turista: estética y política del paisaje urbano

El propósito de este ensayo es promover reflexiones sobre el paisaje urbano que vayan más allá del concepto de paisaje natural y de la noción de paisaje como objeto de representación pictórica. Gracias a una excursión inicial por la estética de la impureza propuesta por Mathieu Kessler, se describen los modos de ser del viajero y del turista: dos de los posibles enfoques perceptivos del paisaje que implican, cada uno a su manera, una particular disposición para la felicidad en el espacio geográfico. Semejante descripción ético-estética se amplia para recorrer, en sus complicidades, tensiones y paradojas, el modo de ser “citadino” o “ciudadano” de quien transita la ciudad contemporánea. Se defiende así la idea de que el exceso de ciudad que constituye ontológicamente la urbe contemporánea es en parte compensado —felicidad en la infelicidad— con la disposición ético-estética del transeúnte urbano.-----The aim of this essay is to promote thought on urban landscapes that go further than the concept of natural landscapes and than the notion of a landscape as an object of pictorial representation. Thanks to an initial digression of the esthetics of impurity proposed by Mathieu Kessler, the traveler’s and tourist’s way of being are described: two of the possible landscape’s perceptive focuses that imply, each in their own way, a particular disposition towards joy in the geographical area. Such ethical-esthetic description is widened to cover, the “urban city dweller” or the “citizen’s” ways of being and transiting the contemporary city within its complicities, pressures and paradoxes; thus defending the idea that the excess city which ontologically constitutes the contemporary metropolis is in part compensated –happiness in unhappiness– with the ethical-esthetic disposition of the temporary urban resident.

An empirical note on factor shares

In this study, we propose an explanation for why labor and capital shares do not seem to have a trend: an increasing trend in physical capital share is compensated by a decreasing trend in land share. Similarly, an increasing trend in human capital share is compensated by a decreasing trend in raw labor share. We also find empirical support for the claim that the elasticity of output with respect to reproducible factors, human and physical capital, is positively correlated with the income level. This result has important implications for economic growth theory and for empirical exercises related to economic growth

Doctors´ remuneration schemes and hospital competition in two-sided markets with common network externalities

This paper uses a two-sided market model of hospital competition to study the implications of di§erent remunerations schemes on the physiciansí side. The two-sided market approach is characterized by the concept of common network externality (CNE) introduced by Bardey et al. (2010). This type of externality occurs when occurs when both sides value, possibly with di§erent intensities, the same network externality. We explicitly introduce e§ort exerted by doctors. By increasing the number of medical acts (which involves a costly e§ort) the doctor can increase the quality of service o§ered to patients (over and above the level implied by the CNE). We Örst consider pure salary, capitation or fee-for-service schemes. Then, we study schemes that mix fee-for-service with either salary or capitation payments. We show that salary schemes (either pure or in combination with fee-for-service) are more patient friendly than (pure or mixed) capitations schemes. This comparison is exactly reversed on the providersíside. Quite surprisingly, patients always loose when a fee-for-service scheme is introduced (pure of mixed). This is true even though the fee-for-service is the only way to induce the providers to exert e§ort and it holds whatever the patientsívaluation of this e§ort. In other words, the increase in quality brought about by the fee-for-service is more than compensated by the increase in fees faced by patients.

Works Councils: An Agency Perspective

This paper investigates the role of works councils in a simple agency framework in whichworks councils are supposed to monitor manager's information on behalf of the workforce,but they are independent agents who might pursue their private interest. First, we considerthat workers can incentivize works councils through contingent monetary payments. In orderto deter collusion, workers must pay higher compensations in states of nature where they canbe expropriated by potential coalitions among works councils and management. Collusionmakes contingent payments costly and reduces workers' payoffs. Second, when elections areused to align works councils' interest only well compensated representatives would face aninter-temporal trade-off between accepting management's transfers at first period and losingrents at the second period. Elections increase the cost of entering on collusive behaviour withmanagement and works councils will try to behave on the employees' interest.

Works councils: an agency perspective

This paper investigates the role of works councils in a simple agency framework in which works councils are supposed to monitor manager’s information on behalf of the workforce, but they are independent agents who might pursue their private interest. First, we consider that workers can incentivize works councils through contingent monetary payments. In order to deter collusion, workers must pay higher compensations in states of nature where they can be expropriated by potential coalitions among works councils and management. Collusion makes contingent payments costly and reduces workers’ payoffs. Second, when elections are the exclusive mechanisms to align works councils’ interest, only well compensated representatives would face an intertemporal tradeoff between accepting management’s transfers at first period and losing rents at the second period. Elections increase the cost of entering on collusive behavior with management and works councils will try to behave on the employees’ interest.

Informality in the City: a Theoretical Analysis

This thesis theoretically studies the relationship between the informal sector (both in the labor and the housing market) and the city structure.