Polymers selection for a liquid inoculant of Azospirillum brasilense based on the Arrhenius thermodynamic model

Plant growth promoting bacteria (PGPB) enhances the growth of their hosts and can protect them from biotic and abiotic stresses. Bacterial inoculants contain one or more of these beneficial strains in a carrier material, which must be able to maintain the viability of the cells during the time of storage, and also guarantee the biological activity of the strains once applied in the soil. These inoculants can be solid, liquid, gel or oil-based, depending on the characteristics of the strains and the shelf life expected by the producers. In this study, we used a method of accelerated degradation to select a polymer and a concentration to maintain cell stability of a liquid inoculant based on the strain C16 Azospirillum brasilense. A screening at 45°C was made to compare the protectant effect of five polymers on the viability of the strain (p/v): carrageenan (1.5%), sodium alginate (1%), trehalose (10 mM), polyvinylpyrrolidone (2%), glycerol (10 mM) and phosphate saline buffer as control. Carrageenan and sodium alginate showed significant differences in cell viability over the use of other polymers (P < 0.05). We evaluated cell viability with these two polymers at three concentrations and three different temperatures (4, 28 and 45°C) for 60 days and determined the bacterial degradation rates. Based on the Arrhenius thermodynamic model, we calculated the time required to reduce cell concentration in three log units, and observed that the protectant activity of each polymer and each concentration depends on the temperature of storage. Cell viability was best preserved in all treatments at 4°C. In general, alginate prolonged cell viability at 28°C, and carrageenan at 45°C. Alginate at 1% and  carrageenan at 0.75% showed a stable behavior (superior to the control) in the three evaluated temperatures, so we conclude that they can be used for a  formulation of a liquid inoculant based on the strain C16 of A. brasilense.Key words: Energy of activation, degradation, cell death, kinetics, formulation

Rumen function and digestion parameters associated with differences between sheep in methane emissions when fed chaffed lucerne hay

An indoor experiment involving 10 rumen-cannulated Romney sheep was conducted in May and June 1998 at AgResearch Grasslands, Palmerston North, New Zealand, under restricted feeding conditions. in order to test the hypothesis that animal factors, in particular rumen fractional outflow rate (FOR) and rumen volume, have an influence on the between-sheep variation in methane (CH4) emission. Sheep were fed 2-hourly on chaffed lucerne hay. Following an acclimatization period of 21 days, the experiment lasted 16 days. Energy and nitrogen (N) balances were measured on days 1-6. Cr-EDTA marker was continuously infused into the rumen from day 9 to 16, and rumen contents emptied and sampled on days 13 and 16. Particulate and fluid FOR were estimated using feed lignin and Cr-EDTA, respectively. Daily CH, production was measured by the sulphur hexafluoride tracer technique on days 2, 5, 6, 12 and 15 of the experiment. CH4 production (g/day) was positively correlated with the pool size of organic matter (OM) in the rumen (OM pool, g) (r = 0.84, P = 0.002), OM intake (OMI, g/day) (r = 0.67, P = 0.04), and the rumen fill (g. wet digesta) (r = 0.76, P = 0.01). Multiple regression analysis showed that CH4 production was best predicted (R-2 = 0.88) as a function of OM pool and the molar % of butyrate; however, OM pool alone accounted for a large proportion (R-2 = 0.71) of the variation in CH4 production. CH4 yield (% gross energy intake, % GEI) was negatively correlated with the particulate FOR (%/h) ( r= -0.75, P = 0.01) and buffering capacity of rumen fluid (mmol HCl) (r = -0.72, P = 0.02) but positively correlated with the digestibility of cellulose (r = 0.66, P = 0.04). Multiple regression analysis showed that CH, yield was best predicted as a function of particulate FOR, OMI (g/kg liveweight(0.75)) and the molar % of butyrate (R-2 = 0.88). Particulate FOR alone explained a large proportion (R-2 = 0.57) of the variation in CH4 Yield. Particulate FOR was negatively correlated with rumen fill (r = -0.69, P = 0.03) and digestibility of cellulose (r = -0.65, P = 0.04). These results suggest that sheep with lower rumen particulate FOR (i.e. longer rumen retention times) had larger rumen fills and higher fibre digestibilities and CH4 yields. If rumen particulate FOR is to be used as a tool for CH4 mitigation, the repeatability of its relationship to CH4 emission must be assessed, preferably under grazing conditions

Persistence of differences between sheep in methane emission under generous grazing conditions

Four low and four high methane (CH4) emitters were selected from a flock of 20 Romney sheep on the basis of CH4 production rates per unit of intake, measured at grazing using the sulphur hexafluoride (SF,) tracer technique. Methane emissions from these sheep were monitored at grazing for four periods (P): October, November, January and February 1999/2000. All measurements were carried out on perennial ryegrass/white clover pasture under generous herbage allowance, and the sheep were maintained on similar pastures during non-measurement periods. The tracer technique was used for all the CH4 measurements and feed DM intake was calculated from total faecal collection and estimated DM digestibility. Data for liveweight (LW), gross energy intake (GEI) and CH4 emission were analysed using split-plot analysis of variance. In addition, a between-period rank order correlation analysis was carried out for CH4 emission data. Low CH4 emitters were heavier (P < 0.05) than the high emitters in all the periods, but they did not differ (P < 0.05) in their gross energy intakes (GEL MJ/kg LW0.75). Low and high CH4 emitters consistently maintained their initial rankings in CH4 yield (% GEI) throughout the subsequent periods and the correlation analysis of rank order for CH4 yield showed strong between-period correlation coefficients, although this was weaker in the last period. It is suggested that feeding conditions that maximize feed intake (e.g. generous allowance of good quality pasture under grazing) favour the expression and persistence of between-sheep differences in CH4 yield

Fault-Tolerant Business Processes

Abstract. Service-oriented computing (SOC) paradigm promotes the idea of assembling application components into a network of loosely coupled services. Web services are the most promising SOC-based technology. A BPEL process definition represents a composite service that encapsulates some complex business logic including the invocation to other (external) web services. The complexity of a BPEL process together with the invocation of external services subject to network and computer failures requires countermeasures to tolerate this kind of failures. In this paper we present an overview of FT-BPEL, a fault-tolerant implementation of BPEL that copes both with failures of the machine running the BPEL process and network failures in a transparent way, that is, after a failure the system is able to resume the BPEL process consistently

Methane emission by alpaca and sheep fed on lucerne hay or grazed on pastures of perennial ryegrass/white clover or birdsfoot trefoil

Based on the knowledge that alpaca (Lama pacos) have a lower fractional outflow rate of feed particles (particulate FOR) from their forestomach than sheep (San Martin 1987), the current study measured methane (CH4) production and other digestion parameters in these species in three successive experiments (1, 2 and 3): Experiment 1, lucerne hay fed indoors; Experiment 2, grazed on perennial ryegrass/white clover pasture (PRG/WC); and Experiment 3, grazed on birdsfoot trefoil (Lotus corniculatits) pasture (Lotus). Six male alpaca and six castrated Romney sheep were simultaneously and successively fed on the forages either ad libitium or at generous herbage allowances (grazing). CH4 production (g/day) (using the sulphur hexafluoride tracer technique), voluntary feed intake (VFI), diet quality, and protozoa counts and volatile fatty acid concentrations in samples of forestomach contents were determined. In addition, feed digestibility, energy and nitrogen (N) balances and microbial N supply from the forestomach (using purine derivatives excretion) were measured in Experiment 1. Diets selected by alpaca were of lower quality than those selected by sheep, and the voluntary gross energy intakes (GEI, MJ) per kg of liveweight(0.75) were consistently lower (P0.05) in their CH4 yields (% GEI) when fed on lucerne hay (5.1 v. 4.7), but alpaca had a higher CH4 yield when fed on PRG/WC (9.4 v. 7.5, P0.05) in diet N partition or microbial N yield, but alpaca had higher (P<0.05) neutral detergent fibre digestibility (0.478 v. 0.461) and lower (P<0.01) urinary energy losses (5.2 v. 5.8 % GEI) than sheep. It is suggested that differences between these species in forestomach particulate FOR might have been the underlying physiological mechanism responsible for the differences in CH4 yield, although the between-species differences in VFI and diet quality also had a major effect on it

Fine root dynamics for forests on contrasting soils in the Colombian Amazon

It has been hypothesized that as soil fertility increases, the amount of carbon allocated to below-ground production (fine roots) should decrease. To evaluate this hypothesis, we measured the standing crop fine root mass and the production of fine roots (<2 mm) by two methods: (1) ingrowth cores and, (2) sequential soil coring, during 2.2 years in two lowland forests growing on different soils types in the Colombian Amazon. Differences of soil resources were defined by the type and physical and chemical properties of soil: a forest on clay loam soil (Endostagnic Plinthosol) at the Amacayacu National Natural Park and, the other on white sand (Ortseinc Podzol) at the Zafire Biological Station, located in the Forest Reservation of the Calderón River. We found that the standing crop fine root mass and the production was significantly different between soil depths (0–10 and 10–20 cm) and also between forests. The loamy sand forest allocated more carbon to fine roots than the clay loam forest with the production in loamy sand forest twice (mean±standard error=2.98±0.36 and 3.33±0.69 Mg C ha−1 yr−1, method 1 and 2, respectively) as much as for the more fertile loamy soil forest (1.51±0.14, method 1, and from 1.03±0.31 to 1.36±0.23 Mg C ha−1 yr−1, method 2). Similarly, the average of standing crop fine root mass was higher in the white-sands forest (10.94±0.33 Mg C ha−1) as compared to the forest on the more fertile soil (from 3.04±0.15 to 3.64±0.18 Mg C ha−1). The standing crop fine root mass also showed a temporal pattern related to rainfall, with the production of fine roots decreasing substantially in the dry period of the year 2005. These results suggest that soil resources may play an important role in patterns of carbon allocation to the production of fine roots in these forests as the proportion of carbon allocated to above- and below-ground organs is different between forest types. Thus, a trade-off between above- and below-ground growth seems to exist with our results also suggesting that there are no differences in total net primary productivity between these two forests, but with higher below-ground production and lower above-ground production for the forest on the nutrient poor soi

Caracterización Molecular de la Diversidad Fúngica de los Bosques Llucud y Palictahua: Potencialidades en Control Biológico/Molecular Characterization of Diversity Fungic of the Llucud and Palictahua Forests: Potential in Biological Control

Dentro de los microorganismos más abundantes que se pueden encontrar en formaciones ecosistémicas naturales como los bosques andinos del Ecuador se encuentran los hongos microscópicos, los cuales desempeñan funciones cruciales en dichos ecosistemas. Por lo cual el objetivo de esta investigación fue caracterizar molecularmente la diversidad de hongos presentes en los bosques nativos Llucud y Palictahua, estableciendo sus potencialidades de uso en el control biológico de plagas y enfermedades que afectan a los cultivos agrícolas y cuyo control en su mayoría se lo realiza con plaguicidas químicos. Mediante secuenciación de próxima generación (NGS por sus siglas en inglés) de las muestras compuestas de suelo tomadas del horizonte “A” (rizósfera) de cada bosque, se identificaron 56 especies de hongos en Palictahua y 38 en Llucud, presentándose en ambos bosques un total de 6 hongos con importantes potencialidades para su uso en el control biológico, dentro de las cuales se encontraron: Brachyphoris oviparasitica (nematófago), Simplicillium (entomopatógeno y micoparásito), Hamamotoa lignophila (levadura con actividad Killer) en Llucud, y Metarhizium robertsii (entomopatógeno), Brachyphoris oviparasitica (nematófago) y Paraphaeosphaeria parmeliae (micoparásito) en Palictahua. El Bosque Palictahua presentó mayor diversidad de hongos que el bosque Llucud, sin embargo es importante cuidar ambos bosques, pues poseen una gran riqueza microbiana con un sinnúmero de posibilidades de uso en la medicina, industria, biotecnología y otros campos. Among the most abundant microorganisms that can be found in natural ecosystem formations such as the Andean forests of Ecuador are microscopic fungi, which play crucial roles in these ecosystems. So that the objective of this research was to molecularly characterize the diversity of fungi present in the native forests Llucud and Palictahua, establishing their potential for use in the biological control of pests and diseases that affect agricultural crops and whose control is mostly carried out with chemical pesticides. Through next-generation sequencing (NGS for its acronym in English) of compound samples of soil took from “A” horizon (rhizosphere). 56 species of fungi were identified in Palictahua and 38 in Llucud, presenting in both forests a total of 6 fungi with significant potential for use in biological control, among which were found: Brachyphoris oviparasitica (nematophagous), Simplicillium sp. (entomopathogen and mycoparasite), Hamamotoa lignophila (yeast with Killer activity) in Llucud, and Metarhizium robertsii (entomopathogen), Brachyphoris oviparasitica (nematophagous) and Paraphaeosphaeria parmeliae (mycoparasite) in Palictahua. The Palictahua forest presented greater diversity of fungi than the Llucud forest, however it is important to take care of both forests, since they have a great microbial richness with a myriad of possibilities of use in medicine, industry, biotechnology and other fields. Palabras clave: Biodiversidad, Microbiota, Plaguicidas. Keywords: Biodiversity, Microbiota, Pesticides

Analysis of a gaussian process and feed-forward neural networks based filter for forecasting short rainfall time series

In this paper, an analysis of kernel (GP) and feed-forward neural networks (FFNN) based filter to forecast short rainfall time series is presented. For the FFNN, the learning rule used to adjust the filter weights is based on the Levenberg-Marquardt method and Bayesian approach by the assumption of the prior distributions. In addition, a heuristic law is used to relate the time series roughness with the tuning process. The input patterns for both NN-based and kernel models are the values of rainfall time series after applying a time-delay operator. Hence, the NN´s outputs will tend to approximate the current value of the time series. The time lagged inputs of the GP and their covariance functions are both determined via a multicriteria genetic algorithm, called NSGA-II. The optimization criteria are the quantity of inputs and the filter´s performance on the known data which leads to Pareto optimal solutions. Both filters -FFNN and GP Kernel- are tested over a rainfall time series obtained from La Sevillana establishment. This work proposed a comparison of well-known filter referenced in early work where the contribution resides in the analysis of the best horizon of the forecasted rainfall time series proposed by Bayesian adjustment. The performance attained is shown by the forecast of the next 15 months values of rainfall time series from La Sevillana establishment located in (-31° 1´22.46"S, 62°40´9.57"O) Balnearia, Cordoba, Argentina.http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6706741&isnumber=6706705Fil: Rodriguez Rivero, C. Universidad Nacional de Córdoba; Argentina.Fil: Pucheta, J. Universidad Nacional de Córdoba; Argentina.Fil: Patiño, H. Universidad Nacional de Córdoba; Argentina.Fil: Baumgartner, J. Universidad Nacional de Córdoba; Argentina.Fil: Laboret, S. Universidad Nacional de Córdoba; Argentina.Fil: Sauchelli, V. Universidad Nacional de Córdoba; Argentina.Sistemas de Automatización y Contro

Refining the associations of the Fermi Large Area Telescope Source Catalogs

The Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) was released in February 2010 and the Fermi-LAT 2-Year Source Catalog (2FGL) appeared in April 2012, based on data from 24 months of operation. Since their releases, many follow up observations of unidentified gamma-ray sources (UGSs) were performed and new procedures to associate gamma-ray sources with potential counterparts at other wavelengths were developed. Here we review and characterize all the associations as published in the 1FGL and 2FGL catalog on the basis of multifrequency archival observations. In particular we located 177 spectra for the low-energy counterparts that were not listed in the previous Fermi catalogs, and in addition we present new spectroscopic observations of 8 gamma-ray blazar candidates. Based on our investigations, we introduce a new counterpart category of "candidate associations" and propose a refined classification for the candidate low-energy counterparts of the Fermi sources. We compare the 1FGL-assigned counterparts with those listed in the 2FGL to determine which unassociated sources became associated in later releases of the Fermi catalogs. We also search for potential counterparts to all the remaining unassociated Fermi sources. Finally, we prepare a refined and merged list of all the associations of the 1FGL plus 2FGL catalogs that includes 2219 unique Fermi objects. This is the most comprehensive and systematic study of all the associations collected for the gamma-ray sources available to date. We conclude that 80% of the Fermi sources have at least one known plausible gamma-ray emitter within their positional uncertainty regions.Comment: 26 pages, 24 figures, 7 tables, ApJS accepted for publication (pre-proof version uploaded