621 research outputs found

    Social security and the search behaviour of workers approaching retirement

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    This paper explores the links between unemployment, retirement and their associated public insurance programs. It is a contribution to a growing body of literature focused on a better understanding of the labor behavior of advanced—age workers, which has gained importance as the pension crisis looms. The analysis combines the development of a new theoretical model and a detailed exploration of the empirical regularities using the Spanish Muestra Continua de Vidas Laborales (MCVL) dataset. The model is a extension of the standard search model, designed to reproduce the non—stationary environment faced by workers approaching retirement and to explore the interaction of unemployment benefits and retirement pensions. Via calibrated simulations we show that the basic empirical reemployment and retirement patterns can be rationalized as the optimal responses to both the labor market conditions and the institutional incentives. Generous Unemployment Benefits (for durations of up to two years) together with very significant early retirement penalties, make optimal to stay unemployed without searching for large groups of unemployed workers. This moral hazard problem can he substantially alleviated through institutional reform. Setting the early retirement penalties according to the age when the individual withdraws from the labor force (rather than when he/she claims the pension for the first time) seems particularly beneficial. It increases the labor supply, reduces the financial cost for the social security system and generate enough extra resources to compensate for the welfare loss of those unemployed directly hit by the reform.Unemployment search, job benefit, retirement

    Impact of effectual propensity on entrepreneurial intention

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    For decades, entrepreneurship has been promoted in academia and the tourism sector and seen as an opportunity for new business ventures. In entrepreneurial behaviour, effectual logic shows how individuals use their resources to create new opportunities. This paper aims to determine effectual propensity as an antecedent of entrepreneurial intentions. For this purpose, and based on the TPB model, we conducted our research with tourism students from Cadiz and Seville (Spain) universities with Smart PLS 3. The results show that effectual propensity influences entrepreneurial intentions and that attitude and perceived behavioural control mediate between subjective norms and intentions. Our research has a great added value since effectual propensity is studied for the first time as an antecedent of intentions in people who have never been entrepreneurs.Durante décadas, el emprendimiento ha sido promovido en la academia y el sector del turismo, siendo visto como una oportunidad para nuevas empresas. En el comportamiento emprendedor, la lógica efectual muestra cómo los individuos utilizan sus recursos para crear nuevas oportunidades. Este documento tiene como objetivo determinar la propensión efectual como un antecedente de las intenciones emprendedoras. Con este propósito, y basándonos en el modelo TPB, llevamos a cabo nuestra investigación con estudiantes de turismo de las universidades de Cádiz y Sevilla (España) utilizando Smart PLS 3. Los resultados muestran que la propensión efectual influye en las intenciones emprendedoras y que la actitud y el control conductual percibido median entre las normas subjetivas e intenciones. Nuestra investigación tiene un gran valor agregado, ya que la propensión efectual se estudia por primera vez como antecedente de intenciones en personas que nunca han sido emprendedoras

    Maintenance of immune tolerance by Foxp3+ regulatory T cells requires CD69 expression

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    Although FoxP3+ regulatory T cells are key players in the maintenance of immune tolerance and autoimmunity, the lack of specific markers constitute an obstacle to their use for immunotherapy protocols. In this study, we have investigated the role of the C-type lectin receptor CD69 in the suppressor function of Tregs and maintenance of immune tolerance towards harmless inhaled antigens. We identified a novel FoxP3+CD69+ Treg subset capable to maintain immune tolerance and protect to developing inflammation. Although CD69+ and CD69−FoxP3+ Tregs exist in homeostasis, only CD69-expressing Tregs express high levels of CTLA-4, ICOS, CD38 and GITR suppression-associated markers, secrete high amounts of TGFβ and have potent suppressor activity. This activity is regulated by STAT5 and ERK signaling pathways and is impaired by antibody-mediated down-regulation of CD69 expression. Moreover, immunotherapy with FoxP3+CD69+ Tregs restores the homeostasis in Cd69−/− mice, that fail to induce tolerance, and is also highly proficient in the prevention of inflammation. The identification of the FoxP3+CD69+ Treg subset paves the way toward the development of new therapeutic strategies to control immune homeostasis and autoimmunityThis work was supported by funding from the Spanish Ministry of Economy and Competitiveness: SAF2011-27330 to P.M., SAF2010-15106 to M.L.T and SAF2011-25834 to F.S-M.; grant INDISNET (S2010/BMD-2332) from Comunidad de Madrid and RETICS Enfermedades Cardiovasculares (RD12/0042/0056) from Instituto de Salud Carlos III to P.M and F. S-M; and ERC-2011-AdG294340-GENTRIS to F.S-M. J.R.C. was supported by a CNIC post-doctoral fellowship, R. S-D is funded with a pre-doctoral fellowship from Comunidad de Madrid and E.R.B. and A.M-M. were supported by a FPI pre-doctoral fellowship from the Spanish Ministry of Economy and Competitiveness. The CNIC is supported by the Spanish Ministry of Economy and Competitiveness and the Pro CNIC Foundatio

    Signaling through the leukocyte integrin LFA-1 in T cells induces a transient activation of Rac-1 that is regulated by Vav and PI3K/Akt-1

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    12 p.-8 fig.Integrin LFA-1 is a receptor that is able to transmit multiple intracellular signals in leukocytes. Herein we show that LFA-1 induces a potent and transient increase in the activity of the small GTPase Rac-1 in T cells. Maximal Rac-1 activity peaked 10-15 min after LFA-1 stimulation and rapidly declined to basal levels at longer times. We have identified Vav, a guanine nucleotide exchange factor for Rac-1, and PI3K/Akt, as regulators of the activation and inactivation phases of the activity of Rac-1, respectively, in the context of LFA-1 signaling based on the following experimental evidence: (i) LFA-1 induced activation of Vav and PI3K/Akt with kinetics consistent with a regulatory role for these molecules on Rac-1, (ii) overexpression of a constitutively active Vav mutant induces activation of Rac independently of LFA-1 stimulation whereas overexpression of a dominant-negative Vav mutant blocks LFA-1-mediated Rac activation, (iii) pharmacological inhibition of PI3K/Akt prevented the fall in the activity of Rac-1 after its initial activation but had no effect on Vav activity, and (iv) overexpression of a dominant-negative or a constitutively active Akt-1 induced or inhibited, respectively, Rac-1 activity. Finally, we show that T cells with a sustained Rac activity have impaired capacity to elongate onto ICAM-1. These results demonstrate that down-regulation of the activity of this GTPase is a requirement for the regulation of T cell morphology and motility and highlight the importance of temporal regulation of the signaling triggered from this integrin.This work was supported in part by Grants CICYT SAF 2001–2807 from Ministerio de Ciencia y Tecnología and FIS-01/1367 from Ministerio de Sanidad y Consumo (to C. C.), a fellowship from Comunidad de Madrid (to L. S.-M.), a Formación de Profesorado Universitario predoctoral fellowship from Ministerio de Educación, Cultura y Deporte (to N. S.-S.), and a postdoctoral fellowship from Ministerio de Educación, Cultura y Deporte (to M. D. G.-L.).Peer reviewe

    Maintenance of immune tolerance by Foxp3+ regulatory T cells requires CD69 expression

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    Although FoxP3+ regulatory T cells are key players in the maintenance of immune tolerance and autoimmunity, the lack of specific markers constitute an obstacle to their use for immunotherapy protocols. In this study, we have investigated the role of the C-type lectin receptor CD69 in the suppressor function of Tregs and maintenance of immune tolerance towards harmless inhaled antigens. We identified a novel FoxP3+CD69+ Treg subset capable to maintain immune tolerance and protect to developing inflammation. Although CD69+ and CD69-FoxP3+ Tregs exist in homeostasis, only CD69-expressing Tregs express high levels of CTLA-4, ICOS, CD38 and GITR suppression-associated markers, secrete high amounts of TGFβand have potent suppressor activity. This activity is regulated by STAT5 and ERK signaling pathways and is impaired by antibody-mediated down-regulation of CD69 expression. Moreover, immunotherapy with FoxP3+CD69+ Tregs restores the homeostasis in Cd69-/- mice, that fail to induce tolerance, and is also highly proficient in the prevention of inflammation. The identification of the FoxP3+CD69+ Treg subset paves the way toward the development of new therapeutic strategies to control immune homeostasis and autoimmunity.This work was supported by funding from the Spanish Ministry of Economy and Competitiveness: SAF2011-27330 to P.M., SAF2010-15106 to M.L.T and SAF2011-25834 to F.S-M.; grant INDISNET (S2010/BMD-2332) from Comunidad de Madrid and RETICS Enfermedades Cardiovasculares (RD12/0042/0056) from Instituto de Salud Carlos III to P.M and F. S-M; and ERC-2011-AdG294340-GENTRIS to F.S-M. J.R.C. was supported by a CNIC post-doctoral fellowship, R. S-D is funded with a pre-doctoral fellowship from Comunidad de Madrid and E.R.B. and A.M-M. were supported by a FPI pre-doctoral fellowship from the Spanish Ministry of Economy and Competitiveness. The CNIC is supported by the Spanish Ministry of Economy and Competitiveness and the Pro CNIC Foundation.Peer Reviewe

    Control of lymphocyte shape and the chemotactic response by the GTP exchange factor Vav

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    7 FiguresRho GTPases control many facets of cell polarity and migration; namely, the reorganization of the cellular cytoskeleton to extracellular stimuli. Rho GTPases are activated by GTP exchange factors (GEFs), which induce guanosine diphosphate (GDP) release and the stabilization of the nucleotide-free state. Thus, the role of GEFs in the regulation of the cellular response to extracellular cues during cell migration is a critical step of this process. In this report, we have analyzed the activation and subcellular localization of the hematopoietic GEF Vav in human peripheral blood lymphocytes stimulated with the chemokine stromal cell–derived factor-1 (SDF-1α). We show a robust activation of Vav and its redistribution to motility-associated subcellular structures, and we provide biochemical evidence of the recruitment of Vav to the membrane of SDF-1α–activated human lymphocytes, where it transiently interacts with the SDF-1α receptor CXCR4. Overexpression of a dominant negative form of Vav abolished lymphocyte polarization, actin polymerization, and migration. SDF-1α–mediated cell polarization and migration also were impaired by overexpression of an active, oncogenic Vav, although the mechanism appears to be different. Together, our data postulate a pivotal role for Vav in the transmission of the migratory signal through the chemokine receptor CXCR4.From the Servicio de Inmunología, Hospital Universitario de la Princesa,Madrid, Spain; Centro de Investigación del Cáncer (CIC), Campus Miguel deUnamuno, Salamanca, Spain; and Facultad de Medicina, Universidad Autónoma de San Luis Potosí (UASLP), San Luis Potosí, Mexico.Peer reviewe

    Nosocomial outbreak of Pseudomonas aeruginosa endophthalmitis

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    We describe an outbreak of nosocomial endophthalmitis due to a common source, which was determined to be trypan blue solution prepared in the hospital's pharmacy service. We assume that viable bacteria probably gained access to the trypan blue stock solution during cooling after autoclaving. The temporal cluster of Pseudomonas aeruginosa endophthalmitis was readily perceived on the basis of clinical and microbiological findings, and an exogenous source of contamination was unequivocally identified by means of DNA fingerprinting. © 2006 by The Society for Healthcare Epidemiology of America. All rights reserved

    An Unusual Case of Locally Advanced Glycogen-Rich Clear Cell Carcinoma of the Breast

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    Glycogen-rich clear cell (GRCC) is a rare subtype of breast carcinoma characterized by carcinoma cells containing an optically clear cytoplasm and intracytoplasmic glycogen. We present the case of a 55-year-old woman with a palpable mass in the right breast and clinical signs of locally advanced breast cancer (LABC). The diagnosis of GRCC carcinoma was based on certain histopathological characteristics of the tumor and immunohistochemical analysis. To our knowledge, this is the first case of GRCC LABC with intratumoral calcifications. There is no evidence of recurrence or metastatic disease after 14 months’ follow-up

    Daycare center attendance buffers the effects of maternal authoritarian parenting style on physical aggression in children

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    A maternal authoritarian style has been related to the development of physical aggression during childhood and later future social problems; however, not too many studies have detected other than individual or family factors that may buffer this maternal effect. This work examines whether daycare center attendance may moderate the relationships between a mother authoritarian style and physical aggression. The study sample was 72 (40 girls) kindergarten children from Spain. Parents were asked to complete two questionnaires focused on individual family characteristics and parenting styles. At age 5, children physical aggression was assessed by direct observation at playtime; aggression scores at 6 was obtained by a peer-rated questionnaire. A least squared multiple regression was performed after controlling for children’s level of physical aggression at 5, child sex and siblings. A positive contribution of maternal authoritarian style on physical aggression was detected. Daycare center attendance appears to attenuate the effect of the mother’s authoritarian style on physical aggression, only in boys.This study was funded by the Andalusian Regional Government’s Plan Andaluz de Investigación (PAI-2003/04, HUM-554) and by the Basque Country Government (GIC07/19-IT-238-07)

    Theoretical study on the hydrophobic and hydrophilic hydration on large solutes: The case of phthalocyanines in water

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    A theoretical study on the hydration phenomena of three representative Phthalocyanines (Pcs): the metal-free, H2Pc, and the metal-containing, Cu-phthalocyanine, CuPc, and its soluble sulphonated derivative, [CuPc(SO3)4]4−, is presented. Structural and dynamic properties of molecular dynamics trajectories of these Pcs in solution were evaluated. The hydration shells of the Pcs were defined by means of spheroids adapted to the solute shape. Structural analysis of the axial region compared to the peripheral region indicates that there are no significant changes among the different macrocycles, but that of [CuPc(SO3)4]4−, where the polyoxoanion presence induces a typically hydrophilic hydration structure. The analyzed water dynamic properties cover mean residence times, translational and orientational diffusion coefficients, and hydrogen bond network. These properties allow a thorough discussion about the simultaneous existence of hydrophobic and hydrophilic hydration in these macrocycles, and indicate the trend of water structure to well define shells in the environment of hydrophobic solutes. The comparison between the structural and dynamical analysis of the hydration of the amphipathic [CuPc(SO3)4]4− and the non-soluble Cu–Pc shows a very weak coupling among the hydrophilic and hydrophobic fragments of the macrocycle. Quantitative results are employed to revisit the iceberg model proposed by Frank and Evans, leading to conclude that structure and dy- namics support a non-strict interpretation of the iceberg view, although the qualitative trends pointed out by the model are supported.Junta de Andalucía P11-FQM7607Ministerio de Ciencia e Innovación CTQ2008-0527
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