HAS PAGA MET ITS FINAL MATCH? CONTINUED EXPANSION OF CALIFORNIA’S PRIVATE ATTORNEYS GENERAL ACT LEADS TO TRADE GROUP’S CONSTITUTIONAL CHALLENGE

HAS PAGA MET ITS FINAL MATCH? CONTINUED EXPANSION OF CALIFORNIA’S PRIVATE ATTORNEYS GENERAL ACT LEADS TO TRADE GROUP’S CONSTITUTIONAL CHALLENG

Is there any relationship between the rates of interest and profit in the U.S. economy?

This paper studies the empirical relationship between the Federal funds effective rate and the rate of profit or profit-to-capital ratio in the U.S. economy. The linkages between these two variables are studied: 1) at business-cycle frequencies using various filters and employing cross-correlation, regression and simulation analysis; and 2) using Vector Autoregressive models that unveil the dynamic interactions between the variables. The different empirical results reveal that positive shocks in the fed funds interest rate generate negative responses of the rate of profit, thus corroborating previous findings that show that a tight monetary policy is associated with lower aggregate profitability level

On the interaction between economic growth and business cycles

The present paper studies the interaction between short-run fluctuations and economic growth by presenting empirical evidence of the impact of business cycle fluctuations on the rate of growth consistent with a constant unemployment rate in 13 Latin American and 18 OECD countries during the period 1981-2011. The results of both parametric (OLS and a panel estimator that allows for parameter heterogeneity and cross section dependence) and non-parametric (a penalized regression spline estimator) econometric techniques show that this measure of potential output experiences positive (negative) changes in periods of high (low) growth in the majority of countries, and, hence, that business cycles fluctuations have statistically significant effects on potential output. However, in contrast to the sample of OECD countries, less than half of the sample of Latin American countries experience statistically significant changes of this measure of potential output in periods of low growth

Caracterització molecular de subunitats reguladores de la fosfatasa Ppz1 en el llevat Saccharomyces cerevisiae

Consultable des del TDXA la portada: Facultat VeterinàriaTítol obtingut de la portada digitalitzadaLa fosfo-defosforilación de aminoácidos es uno de los procesos de regulación reversible más extendidos en los seres vivos. Este tipo de reacciones es llevado a cabo por la acción opuesta de las proteínas quinasas y las proteínas fosfatasas. A pesar de ello, el genoma de la levadura codifica un número mayor de Ser/Thr quinasas. Por ello, algunas fosfatasas han desarrollado un mecanismo de regulación distinto, que se basa en la unión de la subunidad catalítica a una o más subunidades reguladoras. Éstas determinan la localización subcelular, la especificidad por el sustrato y, en definitiva, la función de la fosfatasa. Éste es el caso de la fosfatasa de tipo 1, que está codificada por GLC7 en la levadura Saccharomyces cerevisiae, un enzima esencial que desarrolla funciones muy importantes en la biología de la célula y cuya función está regulada por la unión de la subunidad catalítica a multitud de subunidades reguladoras distintas. El genoma de la levadura codifica dos fosfatasas, conocidas con el nombre de Ppz1 y Ppz2 y cuya mitad carboxiterminal está relacionada estructuralmente con Glc7. A pesar de no ser esenciales, estas fosfatasas desarrollan un papel importante en la biología de la levadura Saccharomyces cerevisiae. En concreto, ejercen un control negativo sobre la tolerancia salina y la progresión del ciclo celular y positivo en el mantenimiento de la integridad celular. En el momento de iniciar este trabajo sólo se conocía una subunidad reguladora de estas fosfatasas, conocida con el nombre de Hal3 o Sis2. Esta proteína actúa como inhibidora de todas las funciones conocidas de Ppz1. Sin embargo, su mecanismo de actuación es desconocido. El primer objetivo de este trabajo ha sido intentar profundizar en la regulación que lleva a cabo la fosfatasa Ppz1 en el control del ciclo celular de la levadura. Para ello, se ha generado un doble mutante condicional sit4 hal3 que presenta una parada entre las fases G1 y S del ciclo. Esta cepa se ha transformado con dos genotecas multicopia diferentes. Gracias a ello se han podido aislar una serie de genes que, en multicopia son capaces de suprimir el fenotipo de esta cepa. Entre ellos se encuentran elementos reguladores del ciclo celular ya conocidos, algunas fosfatasas, elementos involucrados en homeostasis salina y tres genes cuya función era desconocida por el momento, que han sido renombrados VHS1, VHS2 y VHS3. En segundo lugar, se ha investigado el mecanismo de acción de Hal3 sobre la fosfatasa Ppz1. Para ello se han estudiado elementos hallados en la secuencia de Hal3 posiblemente relevantes para la función de esta proteína. Además, se ha realizado una estrategia de mutagénesis al azar de la zona más conservada de Hal3 seguida de una búsqueda de pérdida de función. Esto ha permitido hallar una serie cambios aminoacídicos únicos que interfieren en la función de Hal3. La caracterización bioquímica posterior ha permitido determinar dos regiones en la secuencia de Hal3 importantes para la unión a Ppz1 y una tercera región importante para inhibir a la fosfatasa. Finalmente, se ha estudiado el papel biológico de YFR003c, un ORF cuya función era desconocida por el momento. Estos estudios han demostrado que codifica una proteína con características afines a los inhibidores de la fosfatasa de tipo 1 humana. Además, se ha podido demostrar que Yfr003c es capaz de unirse e inhibir in vitro a Glc7 y, con menor eficiencia, a Ppz1. Estudios posteriores in vivo refuerzan la hipótesis del papel de Yfr003c como inhibidor de Glc7. Por este motivo, ha recibido el nombre de Ypi1 (Yeast Phosphatase 1 Inhibitor) y se ha propuesto como el primer inhibidor conocido de Glc7 en la levadura Saccharomyces cerevisiae.Phospho-dephosphorylation of amino acids is one of the most extended mechanisms of reversible regulation found in living organisms. This kind of reactions is driven by the opposite action of kinases and phosphatases. In spite of this fact, yeast genome encodes more Ser/Thr protein kinases. For this reason some phosphatases have developed a different regulatory mechanism based on the union of the catalytic subunit to one or more regulatory proteins which in turn regulate the subcellular location, the specificity for substrate and thus, the function of the phosphatase. This is the case of Protein Phosphatase 1, encoded by the essential gene GLC7 in the yeast Saccharomyces cerevisiae. This enzyme plays an important role in the yeast and it is tightly regulated by the union of the catalytic subunit to different regulatory proteins. The genome of the yeast also encodes two phosphatases, named Ppz1 and Ppz2 that are structurally related to Glc7. Although they are not essential, they also play an important role in the biology of the yeast. These phosphatases act negatively in the control of the progression of cell cycle and in the maintenance of the salt tolerance and positively in the control of osmotic integrity. In the early steps of this work there was described only one regulatory subunit of these phosphatases named Hal3 or Sis2. Although its specific mechanism of function is still unknown it has been described that this protein acts as an inhibitor for all the known functions of Ppz1. In this work we tried to deepen in the regulation of the cell cycle progression driven by Ppz1. For this reason, we created a conditional sit4 hal3 double mutant, which presents, in non-permissive conditions, a blockade between the G1 and S phases of the cell cycle. This strain was transformed with two different multicopy libraries and colonies able to grow in non-permissive conditions were selected and plasmidic DNA extracted and sequenced. This procedure allowed us to identify a total of 13 genes that, when overexpressed, were able to suppress the phenotype of this strain under non-permissive conditions. They include well-known cell cycle regulatory elements but also some phosphatases, some genes that develop different roles in the control of salt tolerance and three genes with no known function until now that we renamed VHS1, VHS2 and VHS3. We also investigated the regulatory interaction between Hal3 and Ppz1. For this reason, we studied some elements found in the sequence of Hal3 that could be relevant for the function of this protein. Furthermore, we developed a strategy of random mutagenesis of the most conserved region of Hal3 followed by a screening of loss of function of the protein. This procedure allowed us to identify several amino acidic changes that affect Hal3 function in vivo. Biochemical characterization shows the presence of two regions in Hal3 that are important for the union to Ppz1 and a third one that is relevant in the inhibition of the phosphatase activity. Finally, we studied the biological role of YFR003c, an uncharacterized ORF with no known function. Our work demonstrated that YFR003c encodes a protein that shares characteristics commonly found in some inhibitors of the human protein phosphatase 1. We have shown that YFR003c is able to interact with Glc7 and Ppz1 in vitro. Furthermore, YFR003c acts as an inhibitor of Glc7 and, in a lesser degree, of Ppz1. Overexpression studies have shown that YFR003c can act in vivo as an inhibitor of Glc7. For this reason we renamed it YPI1 (for Yeast Phosphatase 1 Inhibitor) and it has been proposed to be the first endogenous inhibitor of Glc7 in the yeast Saccharomyces cerevisiae

Photoautotrophic removal of hydrogen sulfide from biogas using purple and green sulfur bacteria

Producción CientíficaBiogas desulfurization based on anoxygenic photosynthetic processes represents an alternative to physicochemical technologies, decreasing the risk of O2 and N2 contamination. This work aimed at assessing the potential of Allochromatium vinosum and Chlorobium limicola for biogas desulfurization under different light intensities (10 and 25 klx) and H2S concentrations (1, 1.5 and 2%) in batch photobioreactors. In addition, the influence of rising biogas flow rates (2.9, 5.8 and 11.5 L d-1 in stage I, II and III, respectively) on the desulfurization performance in a 2.3 L photobioreactor utilizing C. limicola under continuous mode was assessed. The light intensity of 25 klx negatively influenced the growth of A. vinosum and C. limicola, resulting in decreased H2S removal capacity. An increase in H2S concentrations resulted in higher volumetric H2S removal rates in C. limicola (2.9–5.3 mg L-1 d-1) tests compared to A. vinosum (2.4–4.6 mg L-1 d-1) tests. The continuous photobioreactor completely removed H2S from biogas in stage I and II. The highest flow rate in stage III induced a deterioration in the desulfurization activity of C. limicola. Overall, the high H2S tolerance of A. vinosum and C. limicola supports their use in H2S desulfurization from biogas

Integration of Langevin Equations with Multiplicative Noise and Viability of Field Theories for Absorbing Phase Transitions

Efficient and accurate integration of stochastic (partial) differential equations with multiplicative noise can be obtained through a split-step scheme, which separates the integration of the deterministic part from that of the stochastic part, the latter being performed by sampling exactly the solution of the associated Fokker-Planck equation. We demonstrate the computational power of this method by applying it to most absorbing phase transitions for which Langevin equations have been proposed. This provides precise estimates of the associated scaling exponents, clarifying the classification of these nonequilibrium problems, and confirms or refutes some existing theories.Comment: 4 pages. 4 figures. RevTex. Slightly changed versio

TransfQMix: transformers for leveraging the graph structure of multi-agent reinforcement learning problems

Coordination is one of the most difficult aspects of multi-agent reinforcement learning (MARL). One reason is that agents normally choose their actions independently of one another. In order to see coordination strategies emerging from the combination of independent policies, the recent research has focused on the use of a centralized function (CF) that learns each agent's contribution to the team reward. However, the structure in which the environment is presented to the agents and to the CF is typically overlooked. We have observed that the features used to describe the coordination problem can be represented as vertex features of a latent graph structure. Here, we present TransfQMix, a new approach that uses transformers to leverage this latent structure and learn better coordination policies. Our transformer agents perform a graph reasoning over the state of the observable entities. Our transformer Q-mixer learns a monotonic mixing-function from a larger graph that includes the internal and external states of the agents. TransfQMix is designed to be entirely transferable, meaning that same parameters can be used to control and train larger or smaller teams of agents. This enables to deploy promising approaches to save training time and derive general policies in MARL, such as transfer learning, zero-shot transfer, and curriculum learning. We report TransfQMix's performances in the Spread and StarCraft II environments. In both settings, it outperforms state-of-the-art Q-Learning models, and it demonstrates effectiveness in solving problems that other methods can not solve.This project has received funding from the EU’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 893089. This work acknowledges the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S). We gratefully acknowledge the David and Lucile Packard Foundation.Peer ReviewedPostprint (author's final draft

Absorbing states and elastic interfaces in random media: two equivalent descriptions of self-organized criticality

We elucidate a long-standing puzzle about the non-equilibrium universality classes describing self-organized criticality in sandpile models. We show that depinning transitions of linear interfaces in random media and absorbing phase transitions (with a conserved non-diffusive field) are two equivalent languages to describe sandpile criticality. This is so despite the fact that local roughening properties can be radically different in the two pictures, as explained here. Experimental implications of our work as well as promising paths for future theoretical investigations are also discussed.Comment: 4 pages. 2 Figure

Sticky grains do not change the universality class of isotropic sandpiles

We revisit the sandpile model with ``sticky'' grains introduced by Mohanty and Dhar [Phys. Rev. Lett. {\bf 89}, 104303 (2002)] whose scaling properties were claimed to be in the universality class of directed percolation for both isotropic and directed models. Simulations in the so-called fixed-energy ensemble show that this conclusion is not valid for isotropic sandpiles and that this model shares the same critical properties of other stochastic sandpiles, such as the Manna model. %as expected from the existence of an extra %conservation-law, absent in directed percolation. These results are strengthened by the analysis of the Langevin equations proposed by the same authors to account for this problem which we show to converge, upon coarse-graining, to the well-established set of Langevin equations for the Manna class. Therefore, the presence of a conservation law keeps isotropic sandpiles, with or without stickiness, away from the directed percolation class.Comment: 4 pages. 3 Figures. Subm. to PR