Exploring the Jungle of Intuitionistic Temporal Logics

The importance of intuitionistic temporal logics in Computer Science and Artificial Intelligence has become increasingly clear in the last few years. From the proof-theory point of view, intuitionistic temporal logics have made it possible to extend functional languages with new features via type theory, while from its semantical perspective several logics for reasoning about dynamical systems and several semantics for logic programming have their roots in this framework. In this paper we consider several axiomatic systems for intuitionistic linear temporal logic and show that each of these systems is sound for a class of structures based either on Kripke frames or on dynamic topological systems. Our topological semantics features a new interpretation for the `henceforth' modality that is a natural intuitionistic variant of the classical one. Using the soundness results, we show that the seven logics obtained from the axiomatic systems are distinct.Comment: Under consideration in Theory and Practice of Logic Programming (TPLP). arXiv admin note: text overlap with arXiv:1803.0507

3‐Deaza‐Adenosine Inhibition of Stimulus‐Response Coupling in Human Polymorphonuclear Leukocytes

In an effort to define better the functional role of S‐adenosyl‐methionine‐mediated methylation reactions in modulating polymorphonuclear (PMN) functional responses to chemotactic stimuli, we investigated the effects of 3‐deaza‐adenosine (3‐DZA), a known inhibitor of methylation reactions in phagocytic cells, on formyl methionyl‐leucyl‐phenylalanine (FMLP)‐induced responses in human PMN leukocytes. Using the fluorescent cyanine dye 3,3’‐dipropylthiocarbocyanine (di‐S‐C3‐(5)) as an optical probe of membrane potential we observed that 3‐DZA at concentrations that inhibit FMLP‐induced O2− production does not significantly alter FMLP‐induced changes in transmembrane potential. Additional studies showed an inhibitory effect of 3‐DZA on FMLP‐induced PMN pinocytosis and to a lesser degree on FMLP‐induced degranulation. However, pretreatment of PMNs with 3‐DZA did not alter FMLP‐induced changes in Quin‐2 fluorescence, an indicator of changes in intracellular calcium levels. These findings demonstrate a dissociation between chemotactic factor‐induced cell membrane depolarization, changes in intracellular calcium, and specific neutrophil functional responses and suggest that chemotactic factor‐induced changes in transmembrane potential and intracellular calcium are independent of chemotactic factor‐induced methylation reactions. Furthermore, 3‐DZA did not alter phorbol myristate acetate induced O2− production or fluid pinocytosis indicating a stimulus specificity for the inhibitory effects of this agent on O2− production.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141044/1/jlb0121.pd

Prostaglandin modulation of N-formylmethionylleucylphenylalanine-induced transmembrane potential changes in rat neutrophils

Prostaglandins of the E-series (PGEs) and PGI2 will inhibit formylmethionylleucylphenylalanine- (f-Met-Leu-Phe) induced lysosomal enzyme release and superoxide-anion (O-2) production by neutrophils. The inhibitory effects of PGEs and PGI2 on neutrophil functional responses have been correlated with their ability to increase intracellular cAMP. In this study we have examined the effects of PGEs and PGI2 on f-Met-Leu-Phe- and phorbol-myristate-acetate-induced rat neutrophil membrane potential changes using an optical probe of membrane potential 3,3-dipropylthiodicarbocyanine iodide. 15-(S)-15-methyl-PGE1 (15-methyl-PGE1), a stable analogue of PGE1 and PGI2 inhibited f-Met-Leu-Phe-induced transmembrane potential changes in a dose-dependent manner. This inhibition was correlated with the ability of these agents to increase intracellular cAMP levels and inhibit O-2 production and degranulation. In contrast, 15-methyl-PGE1 and PGI2, did not inhibit phorbol-myristate-acetate-induced transmembrane potential changes and O-2 production. These results suggest independent mechanisms of activation of neutrophils by phorbol myristate acetate and f-Met-Leu-Phe, and they also suggest that the inhibitory effects of prostaglandins and cAMP on f-Met-Leu-Phe-stimulated cells is at a step or steps prior to activation of those processes involved in effecting changes in transmembrane potential, which are common to both stimuli.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24755/1/0000177.pd

Arroz más nutritivo contra la desnutrición en América Latina

More nutritive rice against malnutrition in Latin America Three topics are addressed briefly: (1) information available on the Fe and Zn contents of the grain of 11 rice cultivars; (2) factors affecting its contents; and (3) a plant breeding strategy proposed to increase the nutritional value of rice in Latin America. The data obtained are backed up by results obtained by the International Rice Research Institute (IRRI) and reveal significant differences among cultivars regarding rice grain Fe and Zn contents in both rough and polished rice. Acceptable Fe and Zn contents were also observed in several commercial varieties; these, however, were never selected to improve this aspect of nutritional quality. Recent scientific data indicate that plant breeding is an effective and reliable tool of reasonable cost to develop improved germplasm with a better nutritional value than current varieties. Research conducted by IRRI, within the framework of the HarvestPlus project, and by CIAT, through the AgroSalud project, indicates that genetic variability does exist in rice regarding grain Fe and Zn contents. In conclusion, it is considered feasible to improve the nutritional quality of rice in Latin America, and advances have been made in several areas.Se tratan brevemente tres temas: 1) la información disponible sobre el contenido de hierro (Fe) y zinc (Zn) del grano en 11 cultivares de arroz; 2) los factores que afectan ese contenido; y 3) una estrategia de fitomejoramiento que se propone para incrementar el valor nutricional del arroz en América Latina. Los datos obtenidos, que son sustentados por los resultados del Instituto Internacional de Investigaciones sobre el Arroz (IRRI), indican diferencias significativas entre los cultivares respecto al contenido de Fe y de Zn del grano, tanto en el arroz integral como en el arroz pulido. Se observó además un contenido aceptable de Fe y de Zn en algunas variedades comerciales; éstas, sin embargo, nunca fueron seleccionadas para mejorar este aspecto de su calidad nutricional. Datos científicos recientes indican que el fitomejoramiento es una herramienta eficaz, confiable y de costo razonable para desarrollar germoplasma mejorado, cuyo valor nutricional sea mayor que el de las variedades corrientes. Las investigaciones realizadas por el IRRI, en el marco del proyecto HarvestPlus, y por el CIAT, a través del proyecto AgroSalud, indican que hay variabilidad genética en el arroz respecto al contenido de Fe y de Zn de su grano. En conclusión, se considera que es factible mejorar la calidad nutricional del arroz en América Latina, tarea en la que se ha logrado avanzar en diversas direcciones

Abundancia y diversidad de las comunidades de streptomyces en seis coberturas vegetales de la franja cafetera del quindío, colombia

Se seleccionaron seis coberturas vegetales de la franja cafetera del Quindío para un estudio comparativa de la estructura comunitaria del genero Streptomyces. Mediante recuento en placa se estimó la abundancia y diversidad morfotípica, y a partir de un análisis de PCR-RFLP del marcador rRNA 16S se estimó la diversidad genética de la comunidad aislada por cultivo y de la fracción complementaria no cultivable obtenida par extracción directa de DNA. Se encontraron diferencias estadísticamente significativas en la abundancia de Streptomyces entre las 6 coberturas vegetales, obteniendo no obstante valores de diversidad morfotípica sirnilares entre las coberturas. En el análisis genético cultivo-independiente se observo un patrón específico para cada cobertura, presentándose la diversidad genética más alta en la comunidad de los bosques. Los resultados demuestran que la estructura de la comunidad de Streptomyces es dependiente de la cobertura vegetal, en cuanto a los parámetros de diversidad y abundancia estudiados. (Para mayor información consulte Vol. 5 No.1, 2000)

Foxp3-positive macrophages display immunosuppressive properties and promote tumor growth

Identification of a population of Foxp3-expressing suppressive macrophages