Chemical Oscillations out of Chemical Noise

The dynamics of one species chemical kinetics is studied. Chemical reactions are modelled by means of continuous time Markov processes whose probability distribution obeys a suitable master equation. A large deviation theory is formally introduced, which allows developing a Hamiltonian dynamical system able to describe the system dynamics. Using this technique we are able to show that the intrinsic fluctuations, originated in the discrete character of the reagents, may sustain oscillations and chaotic trajectories which are impossible when these fluctuations are disregarded. An important point is that oscillations and chaos appear in systems whose mean-field dynamics has too low a dimensionality for showing such a behavior. In this sense these phenomena are purely induced by noise, which does not limit itself to shifting a bifurcation threshold. On the other hand, they are large deviations of a short transient nature which typically only appear after long waiting times. We also discuss the implications of our results in understanding extinction events in population dynamics models expressed by means of stoichiometric relations

Safety and Mission Assurance Acronyms, Abbreviations, and Definitions

This NASA Technical Handbook compiles into a single volume safety, reliability, maintainability, and quality assurance and risk management terms defined and used in NASA safety and mission assurance directives and standards. The purpose of this handbook is to support effective communication within NASA and with its contractors. The definitions in this handbook are updated when the definition of the acronym or term is updated in the originating document

Modelo conceptual de gestión de la matrícula: aproximación desde un enfoque sistémico

Este trabajo aporta un modelo conceptual sistémico de la gestión estratégica de la matrícula para que sirva como referente a cualquier institución educativa y lo tome como plataforma para construir un plan estratégico de acuerdo a sus propias características

Complicaciones obstétricas durante puerperio mediato, en relación a la nueva clasificación de embarazo a término de la ACOG, en el hospital de Vitarte, año 2018

Objective: Determine the association between puerperal complications and the classification of Pregnancy to Term of the ACOG, in the Hospital of Vitarte, year 2018. Materials and methods: The study carried out is analytical, retrospective case-type and control. The study population was made up of patients with intermediate postpartum period and who had some complication during this period. It was represented by 268 patients, with 134 cases and 134 controls with a ratio of 1:1. The information was collected from the Clinical Histories and these were: age, degree of instruction, parity, N° CPN, RPM, BMI, hemoglobin, term pregnancy, type of delivery, duration of vaginal delivery, use of oxytocics, induction of labor, complication of J. labor, Apgar and volume of bleeding. Results: The most common type of puerperal complication was puerperal infection 61.19% and puerperal hemorrhage 30.60%. There was no statistical association between Pregnancy to Term and puerperal complication. Of the factors studied, N° insufficient CPN was 4.5 times more likely to present complication as well as other factors such as multiparity, overweight, anemia and the presence of complication during childbirth. Conclusions: It was found that there is no significant association between the classification of pregnancy in its different subclassifications and the presence of complications during puerperium. In terms of developing more complication, develop a specific type of complication and in a differentiated management between one or another classification of E. to term.Objetivo: Determinar la asociación entre las complicaciones puerperales y la clasificación de Embarazo a Término de la ACOG, en el Hospital de Vitarte, año 2018. Materiales y métodos: El estudio realizado es analítico, retrospectivo de tipo caso y control. La población estudiada estuvo conformada por pacientes con puerperio mediato y que tuvieron alguna complicación durante este lapso. Lo representaron 268 pacientes, con 134 casos y 134 controles con relación de 1:1. La información fue recolectada de las Historias clínicas y estas fueron: edad, grado de instrucción, paridad, N° CPN, RPM, IMC, hemoglobina, embarazo a término, tipo de parto, duración de parto vaginal, uso de oxitócicos, inducción de parto, complicación de T. Parto, ápgar y volumen de sangrado. Resultados: El tipo de complicación puerperal más frecuente fue la Infección puerperal 61,19% seguida de Hemorragia puerperal 30,60%. No hubo asociación estadística entre Embarazo a Término y complicación puerperal. De los factores estudiados el N° CPN insuficientes tuvo 4,5 veces mayor probabilidad de presentar complicación, así como otros factores tales como la multiparidad, el sobrepeso, la anemia y la presencia de complicación durante el parto tuvieron mayor probabilidad de presentar complicación. Conclusiones: Se encontró que no existe asociación significativa entre la clasificación de embarazo en sus diferentes subclasificaciones y la presencia de complicaciones durante puerperio, en términos de desarrollar mayor complicación, generar un tipo en específico de complicación y en un manejo diferenciado entre uno u otra clasificación de E. a término

Aminopropyltransferases Involved in Polyamine Biosynthesis Localize Preferentially in the Nucleus of Plant Cells

Plant aminopropyltransferases consist of a group of enzymes that transfer aminopropyl groups derived from decarboxylated S-adenosyl-methionine (dcAdoMet or dcSAM) to propylamine acceptors to produce polyamines, ubiquitous metabolites with positive charge at physiological pH. Spermidine synthase (SPDS) uses putrescine as amino acceptor to form spermidine, whereas spermine synthase (SPMS) and thermospermine synthase (TSPMS) use spermidine as acceptor to synthesize the isomers spermine and thermospermine respectively. In previous work it was shown that both SPDS1 and SPDS2 can physically interact with SPMS although no data concerning the subcellular localization was reported. Here we study the subcellular localization of these enzymes and their protein dimer complexes with gateway-based Bimolecular Fluorescence Complementation (BiFC) binary vectors. In addition, we have characterized the molecular weight of the enzyme complexes by gel filtration chromatography with in vitro assembled recombinant enzymes and with endogenous plant protein extracts. Our data suggest that aminopropyltransferases display a dual subcellular localization both in the cytosol and nuclear enriched fractions, and they assemble preferably as dimers. The BiFC transient expression data suggest that aminopropyltransferase heterodimer complexes take place preferentially inside the nucleus

The relationship between 100Cr6 steelmaking, inclusion microstructure and rolling contact fatigue performance

A processing-microstructure-performance approach is followed to study three bearing steel samples manufactured from the most frequently used continuous casting routes. The inclusion microstructures of the samples were altered by varying the metallurgy and hot working conditions. Inclusion size distribution information is obtained, showing the steel-making route that results in the highest cleanliness. 3D analysis of inclusion morphologies using electrolytic extraction indicates the irregularities on the surface to be favourable sites for crack nucleation under RCF. Flat-washer and ball-on-rod tests were conducted to study the rolling contact fatigue life of the steels, with the results from the flat-washer testing method being more representative for bearing life. This research suggests that early fatigue of bearings is governed by silicate fragmentation and late fatigue by TiN inclusions

Planejamento do desenvolvimento tecnológico na Petrobrás

O artigo apresenta as motivações que levaram à constatação da necessidade de maior atenção ao planejamento de longo prazo no CENPES. Discute tambem a metodologia seguida na elaboração do Plano Diretor, suas principals conclusões e consequências no planejamento da evolução do desenvolvimento tecnológico na PETROBRÁS

Functional Properties of Lupinus angustifolius

Protein isolates prepared by alkaline solubilization followed by isoelectric precipitation and freeze-drying from six varieties of Lupinus angustifolius (Haags Blaue, Sonate, Probor, Borlu, Boregine, and Boruta) grown in Mexico were evaluated for functional properties: nitrogen solubility, water-holding capacity (WHC), oil holding capacity (OHC), emulsion activity index (EAI), emulsion stability index (ESI), foaming capacity (FC), foam stability (FS), and gelling minimum concentration (GMC). The nitrogen solubility values, WHC, OHC, and FC did not show significant differences between the protein isolates. The solubility of the isolates was minimal at pH of 4.0 and 5.0 while the regions of maximum solubility were found at pH of 2.0 and 10.0. There were significant differences in EAI and ESI depending on the varieties used. The isolates of the Boregine and Borlu varieties showed the highest EAI with 29.3 and 28.3 m2 g−1, respectively, while the lowest index was recorded in the isolate obtained from the Sonate variety (24.6 m2 g−1). Like solubility, these indices also increased at both extremes of pH evaluated; both properties were minimal in the isoelectric pH range (4.0 to 5.0)

Insecticidal activity of the petroleum ether extract of ageratum conyzoides l.

Se estableció que el extracto de éter de petróleo (pe 40-60"') de Ageratum conyzoides L. presenta fuerte actividad insecticida contra larvas de tercer estadio de Musca domestica (Díptera), contra larvas de tercer, cuarto y quinto estadio de Cynthia carye (Lepidoptera) y contra individuos adultos de Acanthoscelides obtectus (Coleóptera). En esta acción insecticida podrían estar involucrados dos flavonoides conocidos que se aislaron de este extracto: eupalestina y lucidina dimetiléter. También se aisló prococeno II, cromeno éste que demostró ser altamente tóxico contra larvas de M. domestica cuando las pruebas de contacto se hicieron irradiando con luz solar. En cambio, no mostró ningún efecto cuando los ensayos se hicieron en la oscuridad o bajo irradiación de luz UV