1,280 research outputs found

    Pulsational frequencies of the eclipsing delta-Scuti star HD 172189

    Full text link
    The eclipsing delta-Scuti star HD 172189 is a probable member of the open cluster IC 4756 and a promising candidate target for the CoRoT mission. The detection of pulsation modes is the first step in the asteroseismological study of the star. Further, the calculation of the orbital parameters of the binary system allows us to make a dynamical determination of the mass of the star, which works as an important constraint to test and calibrate the asteroseismological models. From a detailed frequency analysis of 210 hours of photometric data of HD 172189 obtained from the STEPHI XIII campaign we have identified six pulsation frequencies with a confidence level of 99% and a seventh with a 65% confidence level in the range between 100-300 uHz. In addiction, three eclipses were observed during the campaign, allowing us to improve the determination of the orbital period of the system.Comment: 6 pages, 7 figure

    Fungal growth on coffee husks and spent ground under solidstatecultivation conditions

    Get PDF
    The processing of coffee generates significant amounts of agricultural wastes. Coffee husks, comprised of dry outer skin, pulp and parchment, are probably the major residues from the handling and processing of coffee (1). Coffee spent ground is the main coffee industry residue obtained during the processing of raw coffee powder to prepare instant coffee. Coffee husks and spent ground are generated in more than two millions tons yearly (2), and the major problem encountered by the industries is the disposal of these residues, since they contain some amount of caffeine, polyphenols and tannins, which makes them toxic in nature (3). Filamentous fungi are microorganisms able to growth over complex substrates behind minimal conditions, and play an important role in the generation of natural compounds with high commercial interest. Therefore, the aim of the present work was to evaluate the ability of some fungal strains to growth on coffee husks (basically the parchment skin the hull that surrounds the coffee bean), and spent grounds, as an alternative to add value to these toxic residues. Strains from the genus Aspergillus, Penicillium, Mucor and Neurospora were used. Microbial growth was carried out in Petri plates containing 30% of coffee husks or spent ground and 70% of CzapekDox saline media, pH 5.0. The plates were inoculated with a suspension containing 5´106 spores/g dry residue, and maintained at 28ºC for 5 days. The spore suspension was prepared by scrap down the spores from PDA plates with a sterilized solution of 0.2% Tween 80, and counted in a Neubauer chamber. Cultivations were done in duplicate to each fungal in each different substrate. Radial growth rate (Ur, mm/h) was monitored kinetically measuring colony diameters every 12h. All the evaluated fungal strains showed mycelium presence over both residues. For almost all the strains, the invasion capacity was higher in coffee spent ground than in coffee husks. Highest growth rates were obtained with Neurospora crassa, with values of 0.99 and 0.76 mm/h for spent ground and husks, respectively. It was thus concluded that coffee husks and spent grounds can be successfully used as substrate for fungal strains growth. Among the evaluated strains Neurospora crassa gave the best results and could be thus evaluated in solidstate fermentation processes for the obtainment of compounds with commercial interest from these two agroindustrial residues

    Solid-state fermentation: a strategy for biological detoxification of coffee industry residues

    Get PDF
    Coffee is the second largest traded commodity in the world, after petroleum, and therefore, the coffee industry is responsible for the generation of large amount of residues. Among these residues, coffee silverskin (CS) and spent coffee grounds (SCG) are generated in significant amounts and merit special attention. Despite the large generation, most of these residues are unutilized, being discharged to the environment or burned for elimination, which are not environmentally friendly techniques. The discharge to the environment cause severe contamination and environmental pollution problems due to their toxic nature (presence of polyphenols, caffeine, and tannins), and burning results in the production of carbon dioxide, the green house gas. If the toxic constituents present in these materials could be removed, or, at least degraded to a reasonably low level, it would open new opportunities for the utilization of these residues. Therefore, the development of methods to decrease their toxicity or to utilize them as raw material for the production of value added compounds is of great relevance. Solid-state fermentation (SSF) can be defined as the growth of microorganisms on moistened solid substrate, in which enough moisture is present to maintain microbial growth and metabolism, but there is no free-moving water. In recent years, SSF has received more interest from researchers since several studies have demonstrated that this process may lead to higher yields and productivities or better product characteristics than submerged fermentation systems. Based on the above mentioned aspects, the present study consisted in evaluating the ability of seven different fungal strains from the genus Aspergillus, Mucor, Penicillium, and Neurospora, to grow and release phenolic compounds from CS and SCG under solid-state cultivation conditions, as an alternative for biological detoxification of these residues. The biomass production and content of phenolic compounds released from the substrates were monitored during the cultivations. According to the results, Penicillium purpurogenum, Neurospora crassa and Mucor released the highest amount of phenolic compounds from the materials, contributing thus for their detoxification, since phenolic compounds are closely related to the material toxicity. Biological detoxification of CS and SCG provides environmental benefits for the disposal of these residues, as well as economical benefits for the conversion of them to value added products that can be industrially applied

    Antibacterial protein-based fibres: combining recombinant DNA technology with electrospinning

    Get PDF
    [Excerpt] With the increasing healthcare-associated infections and antibiotic-resistant microorganisms there is a demand not only for new antimicrobial compounds but also for antimicrobial materials. Genetically engineered protein polymers functionalized with bioactive domains offer potential as multifunctional versatile materials for biomedical use. The present work describes the fabrication and characterization of antimicrobial fibre mats comprising the antimicrobial elastin-like recombinamer CM4-A200 [1]. [...]This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01- 0145-FEDER- 007569) through FCT I.P. and by ERDF through COMPETE2020 - POCI. The authors are grateful for funding from FCT (project “FunBioPlas” ERA-IB-2-6/0004/2014) and a fellowship to RM (SFRH-BPD/86470/2012). The authors also thank support from the COST Action MP1206

    Electrospun fibres of an elastin-like polymer functionalized with an antimicrobial domain

    Get PDF
    This work describes the production and characterization of nanofibres of a functionalized elastin-like recombinamer (ELR). The polymer was functionalized with an antimicrobial peptide domain by means of recombinant DNA technology and processed by electrospinning. The electrospun fibres were characterized for their morphology, physical-chemical, antimicrobial and cytotoxicity properties. The electrospun membranes showed no cytotoxicity against skin-related cell lines, suggesting the potential applicability of these materials for skin tissue engineering.This work was supported by FEDER through POFC – COMPETE and by Portuguese funds from FCT through the project PEst-OE/BIA/UI4050/2014. By the Spanish Minister of Economy and Competitiveness (MAT2012-38043-C02-01) and Junta de Castilla y León-JCyL (VA152A12-2 and VA155A12-2), Spain. AC, VS and RM, acknowledge FCT for SFRH/BD/75882/2011, SFRH/BPD/63148/2009 and SFRH-BPD/86470/2012 grants, respectively. The authors also thank support from the COST Action MP1206 “Electrospun Nano-fibres for bio inspired composite materials and innovative industrial applications”.info:eu-repo/semantics/publishedVersio

    Antimicrobial Electrospun Membranes of Selp/Ag Composites

    Get PDF
    Silk-elastin-like proteins (SELPs) are a new class of bioinspired, biologically synthesized block copolymers, composed of silk and elastin repeating units. SELP electrospun fibre mats show potential for application as wound dressings for skin regeneration. In this work, antimicrobial nanofibrous mats were produced by electrospinning SELP solutions containing different concentrations of silver nitrate without addition of reducing agents. The SELP/Ag composite materials demonstrated antimicrobial activity against both Gram– and Gram+ bacteria. Furthermore, the SELP/Ag composite materials showed no cytotoxicity against normal human skin fibroblasts.This work was supported by FCT/MEC through Portuguese funds (PIDDAC) - PEst-OE/BIA/UI4050/2014, PEST-C/FIS/UI607/2011, Matepro - NORTE-07-0124-FEDER-000037. RM, AC and VS, acknowledge FCT for SFRH-BPD/86470/2012, SFRH/BD/75882/2011 and SFRH/BPD/63148/2009 grants, respectively. The authors also thank support from the COST Action MP1206 “Electrospun Nano-fibres for bio inspired composite materials and innovative industrial applications”

    Procedimiento para la integración de la Gestión de la Calidad a la Gestión del Capital Humano en los Centros de Educación Superior

    Get PDF
    La calidad como filosofía de gestión se extiende y la Gestión del Capital Humano debe corresponder a la misma en función de asegurar la gestión de la calidad en las organizaciones. El objetivo del presente trabajo es describir el procedimiento que integra la gestión de la calidad en el sistema de Gestión del Capital  Humano para los centros de educación superior del país. A su vez,  se presentan algunas experiencias de su aplicación en la Universidad Central “Marta Abreu” de Las Villas y las ventajas del mismo como forma de facilitar la implantación de las normas cubanas de la familia 3000 sobre la gestión integrada del capital humano

    The field high-amplitude SX Phe variable BL Cam: results from a multisite photometric campaign. II. Evidence of a binary - possibly triple - system

    Full text link
    Short-period high-amplitude pulsating stars of Population I (δ\delta Sct stars) and II (SX Phe variables) exist in the lower part of the classical (Cepheid) instability strip. Most of them have very simple pulsational behaviours, only one or two radial modes being excited. Nevertheless, BL Cam is a unique object among them, being an extreme metal-deficient field high-amplitude SX Phe variable with a large number of frequencies. Based on a frequency analysis, a pulsational interpretation was previously given. aims heading (mandatory) We attempt to interpret the long-term behaviour of the residuals that were not taken into account in the previous Observed-Calculated (O-C) short-term analyses. methods heading (mandatory) An investigation of the O-C times has been carried out, using a data set based on the previous published times of light maxima, largely enriched by those obtained during an intensive multisite photometric campaign of BL Cam lasting several months. results heading (mandatory) In addition to a positive (161 ±\pm 3) x 109^{-9} yr1^{-1} secular relative increase in the main pulsation period of BL Cam, we detected in the O-C data short- (144.2 d) and long-term (\sim 3400 d) variations, both incompatible with a scenario of stellar evolution. conclusions heading (mandatory) Interpreted as a light travel-time effect, the short-term O-C variation is indicative of a massive stellar component (0.46 to 1 M_{\sun}) with a short period orbit (144.2 d), within a distance of 0.7 AU from the primary. More observations are needed to confirm the long-term O-C variations: if they were also to be caused by a light travel-time effect, they could be interpreted in terms of a third component, in this case probably a brown dwarf star (\geq 0.03 \ M_{\sun}), orbiting in \sim 3400 d at a distance of 4.5 AU from the primary.Comment: 7 pages, 5 figures, accepted for publication in A&

    The pulsating hot subdwarf Balloon 090100001: results of the 2005 multisite campaign

    Full text link
    We present the results of a multisite photometric campaign on the pulsating sdB star Balloon 090100001. The star is one of the two known hybrid hot subdwarfs with both long- and short-period oscillations. The campaign involved eight telescopes with three obtaining UBVR data, four B-band data, and one Stromgren uvby photometry. The campaign covered 48 nights, providing a temporal resolution of 0.36microHz with a detection threshold of about 0.2mmag in B-filter data. Balloon 090100001 has the richest pulsation spectrum of any known pulsating subdwarf B star and our analysis detected 114 frequencies including 97 independent and 17 combination ones. The strongest mode (f_1) in the 2.8mHz region is most likely radial while the remaining ones in this region form two nearly symmetric multiplets: a triplet and quintuplet, attributed to rotationally split \ell=1 and 2 modes, respectively. We find clear increases of splitting in both multiplets between the 2004 and 2005 observing campaigns, amounting to 15% on average. The observed splittings imply that the rotational rate in Bal09 depends on stellar latitude and is the fastest on the equator. We use a small grid of models to constrain the main mode (f_1), which most likely represents the radial fundamental pulsation. The groups of p-mode frequencies appear to lie in the vicinity of consecutive radial overtones, up to the third one. Despite the large number of g-mode frequencies observed, we failed to identify them, most likely because of the disruption of asymptotic behaviour by mode trapping. The observed frequencies were not, however, fully exploited in terms of seismic analysis which should be done in the future with a larger grid of reliable evolutionary models of hot subdwarfs.Comment: accepted for publication in MNRA

    Propiedades puzolánicas de desechos de la industria azucarera (primera parte)

    Get PDF
    Non altered straw and sugar cane bagasse ash (CPC, CBC) collected directly from the boilers in the sugar industry and from non-controlled burning in the open fields turned up to be a reasonably good pozzolana, which can be utilized for the manufacture of lime-pozzolana binders. This paper presents a detailed survey of this material with the aim to use it as raw material in the manufacture of binders.Las cenizas de bagazo y paja de caña de azúcar (CPC, CBC), obtenidas en forma inalterada directamente de las calderas de la fábrica de azúcar, y de la quema incontrolada en el campo, representan una interesante fuente de puzolana reactiva, con potencialidad de ser usada en la preparación de aglomerantes del tipo cal/puzolana. El trabajo que se presenta realizó una evaluación integral de estas puzolanas, con el interés de utilizarlas como materia prima en la producción de aglomerantes
    corecore