209 research outputs found
The Emergence of Enforcement
Get PDFHow do mechanisms that enforce cooperation emerge in a society where none are available and agents are endowed with raw power, that allows a more powerful agent to expropriate a less powerful one?
We study a model where expropriation is costly and agents can choose whether to engage in surplus-augmenting cooperation or engage in expropriation.
While in bilateral relations, if cooperation is not overwhelmingly productive and expropriation is not too costly, the latter will prevent cooperation, when there are three or more agents, powerful ones can become enforcers of cooperation for agents ranked below them. In equilibrium they will expropriate smaller amounts from multiple weaker cooperating agents who in turn will not deviate for fear of being expropriated more
heavily because of their larger expropriation proceeds.
Surprisingly, the details of the power structure are irrelevant for the existence of equilibria with enforcement provided that enough agents are present and one is ranked above all others. These details are instead key to the existence of other highly noncooperative equilibria that obtain in certain cases
Determination of lead and cadmium in titanium dioxide by differential pulse anodic stripping voltammetry
No full textA procedure for the simultaneous determination of lead and cadmium in TiO2, by differential pulse anodic stripping voltammetry (ASV) has been developed. The key feature of the method is the use of triethanolamine (TEA) to remove titanium interference: TiO2 undergoes acidic digestion with HF/H2SO4 at atmospheric pressure, TEA is added to the HCl solution of the residue and the solution is analysed using a standard ASV instrumentation, equipped with a hanging mercury drop electrode. The calibration curves for both lead and cadmium are linear up to 50 mug l(-1) of solution, and the detection limits are I mug l(-1), corresponding to I mug g(-1) of TiO2. Method reliability was tested by comparing the results with those given by electrothermal atomic absorption spectroscopy. The method has been successfully applied for determination of both contaminants in powdered titanium dioxide (raw materials) and in titanium dioxide-containing cosmetics (sunscreen products). (C) 2002 Published by Elsevier Science B.V
Fluorescent probes as markers of oxidative stress in keratinocyte cell lines following UVB exposure
No full textIn this work we describe the development of specific markers for determination of both the membrane and intracellular damage induced by free radicals generated by UVB radiation (5-150 mJ/cm(2)) in cultured keratinocytes. This using simple, specific and sensitive fluorescent probes: cis-parinaric acid (PNA) to monitor membrane lipid peroxidation and 2', 7'-dichloro-dihydrofluorescein diacetate (DCFH-DA) to evaluate the intracellular redox status, in parallel to the fluorimetric determination of the main intracellular antioxidant glutathione. To validate the methodologies, the changes in the intracellular oxidative status following exposure to low doses UVB were measured in both control and N-acetylcysteine-protected cells, in parallel with morphological analyses. UVB induces an early reduction of GSH inside the cell correlated with an increase in the intracellular peroxide content. The effects were time- and dose-dependent. In addition, using a sensitive fluorescent method, we quantitated the release of proteases, a family of proteolytic enzymes greatly involved in the onset/perpetuation of the free radical-induced skin damage from keratinocytes exposed to suberythemal UVB doses (5-15 mJ/cm(2)). The use of these fluorescent probes provides a reliable tool to detect the early signs of damage in keratinocyte cultures (when the apoptotic phenomenon has not yet been triggered) useful for future screening of protective molecules. (C) 2000 Elsevier Science S.A. All rights reserved
Commento Art. 43
No full textSi tratta del commento all'art. 43 della Carta dei diritti fondamentali dell'UE con particolare riferimento alla giurisprudenza della Corte di giustizia e alla legislazione dell'UE, oltre che alla principale dottrina di riferimento
sj-docx-1-new-10.1177_10482911221085728 - Supplemental material for Model Policies to Protect U.S. Fire-Based EMS Responders From Workplace Stress and Violence
No full textSupplemental material, sj-docx-1-new-10.1177_10482911221085728 for Model Policies to Protect U.S. Fire-Based EMS Responders From Workplace Stress and Violence by Jennifer A. Taylor, Regan M. Murray, Andrea L. Davis, Sherry Brandt-Rauf, Joseph A. Allen, Robert Borse, Diane Pellechia and David Piccone in NEW SOLUTIONS: A Journal of Environmental and Occupational Health Policy</p
Las revistas científicas argentinas y su inserción en circuitos internacionales de calidad certificada
Get PDFFil: Piccone, María Sol. Universidad de San Andrés. Departamento de Ciencias Sociales; Argentina.Este trabajo busca -en primera instancia- identificar e indagar las razones más
frecuentes por las cuales algunas revistas científicas argentinas que cumplen con
estrictos requisitos y pretenden entrar en circuitos de calidad de contenidos certificados
institucionalmente, no logran hacerlo. Existe una iniciativa institucional que se
desarrolla a nivel nacional que procura imprimir un sello de calidad a las revistas
argentinas en ciencia. Se trata del Núcleo Básico de Revistas Científicas y Tecnológicas
Argentinas (NB) vehiculizado por el CONICET (Consejo Nacional de Investigaciones
Científicas y Técnicas) a través de uno de sus centros de servicios, el CAICYT (Centro_
Argentino de Información Científica y Tecnológica), que se encarga de gestionar todo el
proceso de evaluación rigurosa, tanto en su forma editorial como en los contenidos.
Actualmente, son pocas las instancias regionales cuyo objetivo es velar por las
características calificadas de los contenidos que se publican en las revistas1 para que las
mismas puedan formar parte de los circuitos de calidad con rango internacional. La
existencia de iniciativas como el NB evidencia una toma de decisión en materia de política científica como parte de una política de desarrollo, en ese campo, a nivel
nacional. En el mismo sentido, el Estado argentino está invirtiendo recursos económicos
y humanos en esta actividad de evaluación, razón por la cual desentrañar, en principio,
si el problema está en alguna etapa del proceso de evaluación o cuáles son los motivos
principales que esgrimen los evaluadores para rechazar el ingreso de algunas revistas
científicas en circuitos de calidad, favorecería su mejor tratamiento y resolución.
También esperamos que los resultados de este estudio abran la posibilidad a las revistas
nacionales de constituirse en una opción de publicación y difusión del conocimiento
científico generado por prestigiosos autores de todo el mundo
sj-docx-2-new-10.1177_10482911221085728 - Supplemental material for Model Policies to Protect U.S. Fire-Based EMS Responders From Workplace Stress and Violence
No full textSupplemental material, sj-docx-2-new-10.1177_10482911221085728 for Model Policies to Protect U.S. Fire-Based EMS Responders From Workplace Stress and Violence by Jennifer A. Taylor, Regan M. Murray, Andrea L. Davis, Sherry Brandt-Rauf, Joseph A. Allen, Robert Borse, Diane Pellechia and David Piccone in NEW SOLUTIONS: A Journal of Environmental and Occupational Health Policy</p
Influence of manganese dioxide and manganic ions on the production of two proteins in Arthrobacter sp.
No full textThe production by Arthrobacter sp. of a 30-kDa surface protein and a 25-kDa cytoplasmic protein was increased by the presence of MnO2 in the medium. This high production was also observed in the presence of MnO4- (Mn VII). N-terminal and partial internal sequences of the 30-kDa surface protein have shown no homology with other known proteins. The role of this protein is still unknown, but its highly induced synthesis is possibly related to the binding or the processing of manganic ion by the cells. The 25-kDa cytoplasmic protein has been identified by its N-terminal matching sequence as a superoxide dismutase isoenzyme (Mn-SOD). SOD activity measurements performed on cytoplasmic fractions are related to the protein amounts observed by gel electrophoresis. Arthrobacter sp. synthesized and exhibited SOD activity in both aerobic and anaerobic conditions, thus suggesting other or additional physiological functions for this enzyme
Influence of manganese dioxide and manganic ions on the production of two proteins in Arthrobacter sp.
No full textThe production by Arthrobacter sp. of a 30-kDa surface protein and a 25-kDa cytoplasmic
protein was increased by the presence of MnO2 in the medium. This high production
was also observed in the presence of MnO4¡ (Mn VII). N-terminal and partial internal
sequences of the 30-kDa surface protein have shown no homology with other known
proteins. The role of this protein is still unknown, but its highly induced synthesis is
possibly related to the binding or the processing of manganic ion by the cells. The
25-kDa cytoplasmic protein has been identi® ed by its N-terminal matching sequence as
a superoxide dismutase isoenzyme (Mn-SOD). SOD activitymeasurements performedon
cytoplasmic fractions are related to the protein amounts observed by gel electrophoresis.
Arthrobacter sp. synthesized and exhibited SOD activity in both aerobic and anaerobic
conditions, thus suggesting other or additional physiological functions for this
enzyme.
Keywords anaerobic respiration, Arthrobacter, manganese oxidation±reduction,
protein expressio
- …
