Quorum sensing activity and control of yeast-mycelium dimorphism in \u3ci\u3eOphiostoma floccosum\u3c/i\u3e

Quorum sensing (QS) activity in Ophiostoma fungi has not been described. We have examined the growth conditions on the control of dimorphism in Ophiostoma floccosum, an attractive biocontrol agent against blue-stain fungi, and its relationship with QS activity. In a defined culture medium with l-proline as the N source, a high inoculum size (107 c.f.u. ml-1) was the principal factor that promoted yeast-like growth. Inoculum size effect can be explained by the secretion of a QS molecule(s) (QSMs) responsible for inducing yeast morphology. QSM candidates were extracted from spent medium and their structure was determined by GC–MS. Three cyclic sesquiterpenes were found. The most abundant molecule, and therefore the principal candidate to be the QSM responsible for yeast growth of O. floccosum, was 1,1,4a-trimethyl-5,6-dimethylene-decalin (C15H24). Other two compounds were also detected

Quorum sensing activity and control of yeast-mycelium dimorphism in \u3ci\u3eOphiostoma floccosum\u3c/i\u3e

Quorum sensing (QS) activity in Ophiostoma fungi has not been described. We have examined the growth conditions on the control of dimorphism in Ophiostoma floccosum, an attractive biocontrol agent against blue-stain fungi, and its relationship with QS activity. In a defined culture medium with l-proline as the N source, a high inoculum size (107 c.f.u. ml-1) was the principal factor that promoted yeast-like growth. Inoculum size effect can be explained by the secretion of a QS molecule(s) (QSMs) responsible for inducing yeast morphology. QSM candidates were extracted from spent medium and their structure was determined by GC–MS. Three cyclic sesquiterpenes were found. The most abundant molecule, and therefore the principal candidate to be the QSM responsible for yeast growth of O. floccosum, was 1,1,4a-trimethyl-5,6-dimethylene-decalin (C15H24). Other two compounds were also detected

Zn-edta degradation by catechol-driven fenton reaction

Zn-EDTA degradabilty by catechol-driven Fenton reaction was studied. Response surface methodology central composite design was employed to maximize this complex degradation. Theoretical speciation calculations were in good agreement with the experimental results. Fenton and Fenton type treatments are typically thought to be applicable only in the highly acidic range, representing a major operational constraint. Interestingly, at optimized concentrations, this CAT-driven Fenton reaction at pH 5.5 achieved 100% Zn-EDTA degradation; 60% COD and 17% TOC removals, using tiny amounts of CAT (50 µM), Fe(III) (445 µM) and H2O2 (20 mM) with no evident ferric sludge

Laminar premixed flat non-stretched lean flames of hydrogen in air

Laminar burning velocity of lean hydrogen + air flames at standard conditions is still a debated topic in combustion. The existing burning velocity measurements possess a large spread due to the use of different measurement techniques and data processing approaches. The biggest uncertainty factor in these measurements comes from the necessity to perform extrapolation to the flat flame conditions, since all of the previously obtained data were recorded in stretched flames. In the present study, laminar burning velocity of lean hydrogen + air flames and its temperature dependence were for the first time studied in stretch-free flat flames on a heat flux burner. The equivalence ratio was varied from 0.375 to 0.5 and the range of the unburned gas temperatures was 278-358 K. The flat flames tended to form cells at adiabatic conditions, therefore special attention was paid to the issue of their appearance. The shape of the flames was monitored by taking OH* images with an EM-CCD camera. In most cases, the burning velocity had to be extrapolated from flat subadiabatic conditions, and the impact of this procedure was quantified by performing measurements in H-2 + air mixtures diluted by N-2. The effect of extrapolation was estimated to be of negligible importance for the flames at standard conditions. The measured burning velocities at 298 K showed an important difference to the previously obtained literature values. The temperature dependence of the burning velocity was extracted from the measured results. It was found to be in agreement with the trends predicted by the detailed kinetic modeling, as opposed to a vast majority of the available literature data. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved

Implementación de una Gestión de Inventarios para elevar la productividad en el almacén de RROV Fametal S.A.C, Chorrillos 2016

La presente investigación tuvo como objetivo principal, describir la realidad del almacén para así implementar una gestión de inventario y evaluar una mejora de la productividad en el almacén de RROV FAMETAL S.A.C Es preciso mencionar que la población de este trabajo es la misma que la muestra y estuvo conformada por los todos los elementos que intervienen en el desarrollo del inventario. La recolección de información se llevó a cabo a través de: observación directa, cuya técnica permitió visualizar almacenamiento y despacho de las existencias, lo cual ayudó a obtener la información en el mismo lugar donde ocurren los hechos. Para el análisis e interpretación de los datos obtenidos, se desarrolló una evaluación de la situación actual del almacén, en el cual se determinó los problemas en el proceso de despacho del almacén, luego se realizó esta misma evaluación una vez implementada la gestión de inventario, los resultados conseguidos se ingresaron al software estadístico llamado SPSS. De lo relatado anteriormente, y de acuerdo al análisis realizado se considera oportuno realizar seguimientos a la realización de los inventarios realizados mensualmente y analizando los resultados respectivos. De todo lo anterior expuesto, y de acuerdo con las observaciones realizadas se considera necesario ejecutar un análisis sistemático que contribuya a identificar y prevenir los modos de fallo, tanto del producto como del proceso, evaluando su gravedad, ocurrencia y detección, mediante los cuales, se calculará el número de prioridad de riesgo, para priorizar las causas, sobre las cuales habrá que actuar para evitar que se presenten dichos modos de fallo. Es necesario mencionar la importancia que tiene la realización de esta investigación ya que permitirá adquirir habilidades y encontrar soluciones a los posibles problemas que se puedan presentar

A new sum of graphs and caterpillar trees

Árboles oruga, o simplemente oruga, son árboles tales que cuandoles quitamos todas sus ramas (o arista final) obtenemos un camino. La cantidad de orugas no isomorfas con n ≥ 2 aristas es 2n−3 + 2⌊(n−3)/2⌋. Usandouna nueva suma de grafos, introducida en este artículo, proporcionamos unanueva prueba de este resultado.Caterpillar trees, or simply Caterpillar, are trees such that when we remove all their leaves (or end edge) we obtain a path. The number of nonisomorphic caterpillars with n ≥ 2 edges is 2n−3 + 2⌊(n−3)/2⌋. Using a new sum of graphs, introduced in this paper, we provided a new proof of this result

Estudio de propiedades de la madera de seis especies nativas en plantaciones de Costa Rica

Artículo científicoThis study details information about physical, chemical and mechanical properties, drying, preservation and workability of wood from Cordia alliodora, Dipteryx panamensis, Enterolobium cyclocarpum, Hieronyma alchorneoides, Samanea saman and Vochysia ferruginea trees, growing in forest plantations in Costa Rica. Variation of the general properties in relation to height showed that heartwood percentage decreases, bark percentage increases and pith percentage is not affected. Dipteryx panamensis showed both the highest values for specific gravity and the highest mechanic resistance. Both chemical properties and extractives presence were different among species. Heartwood was not possible to preserve in any of the species, though sapwood was. Penetration varied from partial irregular or vascular in the species. The highest durability was for Hieronyma alchorneoides and Vochysia ferruginea, species classified as of high durability. Finally, all species had good performance in the workability tests. The previous results indicate that these species, used for trading reforestation in Costa Rica, have acceptable characteristics to be commercialized and used in wooden products

Mejoramiento en la eficiencia del proceso de secado convencional y homogenización en el color de la Albura y el Duramen en madera de Teca (Tectona grandis L.) (Documento I)

Informe final de Proyecto de Investigación. Código: 5401-1401-1030Different drying schedules were investigated to decrease drying time of Tectona grandis L. wood from juvenile plantations, using the drying rate (DR) to reduce time. The DR value was 20% per day during the first stages and by the time the wood reached 30% of moisture content (MC), the DR remained in 8% per day until the end of drying. The initial moisture content (MCi) ranged between 92 and 115%, MCi was affected by grain pattern and heartwood percentage. The final moisture content (MCf) differed in 2.0% in relation to the MC targeted for this study. Drying time can be reduced from 140 hours to 105 hours, maintaining DR conditions and saving 33% of energy consumption. DR is affected by moisture content and drying time and this behavior can be modeled mathematically by the equation Y = a*t + b. In these relations, the factors with greatest influence were dry-bulb temperature and wet-bulb depression. Both relations show an inflexion point in the relation DR-MC, 80% in fast drying schedule and 40% in slow drying schedule. This MC indicates the point where the DR must be changed

WOOD PROPERTIES OF NINE ACETYLATED TROPICAL HARDWOODS FROM FAST-GROWTH PLANTATIONS IN COSTA RICA

The treatment of acetylation on tropical woods is influenced by their different levels of permeability and how these affect the weight percentage gain (WPG) in acetylated wood. The objective of the current study was to identify the effect of acetylation on the thermal stability, color, physical properties, hygroscopic and dimensional stability, wetting rate, and durability of nine tropical species of woods used for the commercial reforestation in Costa Rica. Study results showed that WPG varied from 2.2% to 16.8%. Positive significant correlations were observed between WPG and pre-exponential factors in TGA analysis and two parameters of dimensional and hygroscopic stability, whereas a negative correlation was observed with water absorption. In species with a WPG of over 10% (Vochysia ferruginea, V. guatemalensis, Cordia alliodora, and Enterolobium cyclocarpum) the thermal stability, wetting rate, hygroscopic stability, and resistance to biological attack showed an increase while swelling, and water absorption decreased. For these species, the best behaviors were obtained with an acetylation time of 2.5 hours and WPG values of over 10%. The same properties of wood in species with a WPG under 5% were found to be less affected by the different acetylation times and showed little difference in relation to untreated wood. Finally, the analysis showed that the dimensional stability obtained was attributed to the reduction of the absorptive capacity of the acetylated wood

Evaluación de la composición química, secado al aire, preservación y trabajabilidad de ocho especies de rápido crecimiento en plantación de Costa Rica

Artículo científicoCosta Rica has successfully planted various forestry species for wood production. However, the use of their wood is limited, due to poor knowledge about their chemical properties, air-dry, preserved and workability performance. The present study details information of these properties for the species: Alnus acuminata (Aa), Acacia mangium (Am), Bombacopsis quinata (Bq), Cupressus lusitanica (Cl), Swietenia macrophylla (Sm), Terminalia amazonia (Ta), Terminalia oblonga (To) and Vochysia guatemalensis (Vg). Among the results obtained, it was found that the wood of these species is in general slightly acidic, except Bq, which presented tendency to be basic. Different species show considerable variability in the content of holocellulose, lignin and extractable micronutrients. Regarding micronutrients, and in relation to other species it was found a high percentage in Vg. The use of boron as a preservative, may be applied in the 8 plantation species. The presence of heartwood in some species made it not possible to be preserved by the vacuum-pressure method, but the sapwood was possible to preserve in all species. The drying rate increased with increasing board thickness and drying time was different among species. The fastest drying rate was found in Ta and Am, followed by Sm, To, Aa and Cl with intermediate values and Vg with the slowest air-drying rate. Am, Bq, Cl, Sm and To present from excellent to good planing, sanding , drilling and molding, but Ta, Bq, Aa and Vg, especially Aa and Vg, in the workability operations were catalogued as poor or very poor quality