Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Más filtros










Intervalo de año de publicación
1.
Sci Rep ; 10(1): 11255, 2020 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-32647235

RESUMEN

Dating of wood is a major task in historical research, archaeology and paleoclimatology. Currently, the most important dating techniques are dendrochronology and radiocarbon dating. Our approach is based on molecular decay over time under specific preservation conditions. In the models presented here, construction wood, cold soft waterlogged wood and wood from living trees are combined. Under these conditions, molecular decay as a usable clock for dating purposes takes place with comparable speed. Preservation conditions apart from those presented here are not covered by the model and cannot currently be dated with this method. For example, samples preserved in a clay matrix seem not to fit into the model. Other restrictions are discussed in the paper. One model presented covers 7,500 years with a root mean square error (RMSE) of 682 years for a single measurement. Another model reduced to the time period of the last 800 years results in a RMSE of 92 years. As multiple measurements can be performed on a single object, the total error for the whole object will be even lower.

2.
Sci Rep ; 10(1): 12427, 2020 07 24.
Artículo en Inglés | MEDLINE | ID: mdl-32709969

RESUMEN

Based on infrared spectral characteristics, six archeological sample sets of charcoals from German (5) and Brazilian (1) sites, covering the time span from the nineteenth century CE to 3950 BCE, were compared to a chronological (present to the fifteenth century BCE) series of Austrian charcoals. A typical chronological trend of several bands (stretch vibrations: O-C-O of carboxylates at 1,585-1,565 and 1,385-1,375 cm-1, C-O carboxylic acids at 1,260-1,250 cm-1) that indicate oxidation and subsequently increasing hydrophilicity (O-H stretch vibration at about 3,400 cm-1) was also contained in the archive samples. Three sample sets fit in the typical band development according to their age. For three sample sets this conformity was not observed. Despite the age of two sample sets (3950-2820 BCE), most charcoals were assigned to the Modern Period. Apart from the high degree of carbonization, anaerobic depositional conditions over a longer period of time seem to contribute to the surprising conservation. Non-removable mineral components in charcoals, as observed in a third sample set, strongly influence infrared band intensities and positions of organic compounds. The role of inorganic components in terms of charcoal aging, and the information we can obtain from spectral characteristics in an archeological context, are discussed.

3.
Plant Biol (Stuttg) ; 18(4): 585-93, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26789333

RESUMEN

Most species in Melastomataceae have poricidal anthers related to specialised bee buzz-pollination, while some have anthers with large openings associated to non-bee pollination systems. We tracked the evolution of anther morphology and seed number on the Miconieae phylogenetic tree to understand the evolutionary shifts in such pollination systems. Anther morphometric data and seed number were recorded for 54 taxa. Pollinators (bees, flies, wasps) were recorded for 20 available species. Ancestral state reconstruction was made using Maximum Likelihood from nrITS sequences. We used phylogenetic eigenvector regressions to estimate phylogenetic signal and the adaptive component for these traits. Species pollinated by bees or bees and wasps tend to have smaller pores and fruits with more seeds. Species pollinated by flies or flies and bees and/or wasps tend to have larger pores and fruits with less seeds. Independent evolution occurred three times for anthers with large pores and twice for fruits with few seeds. We detected a phylogenetic signal in both traits, and negative correlated evolution between them. In actinomorphic small-flowered Miconieae, changes in anther morphology can be related to generalisation in the pollination system incorporating flies and wasps as pollinators and lessening the importance of buzzing bees in such process. Differences in pollen removal and deposition may explain differences in anther morphology and seed number in Miconieae.


Asunto(s)
Melastomataceae/fisiología , Polinización , Animales , Abejas/fisiología , Evolución Biológica , Análisis por Conglomerados , Dípteros/fisiología , Flores/anatomía & histología , Flores/genética , Flores/crecimiento & desarrollo , Flores/fisiología , Melastomataceae/anatomía & histología , Melastomataceae/genética , Melastomataceae/crecimiento & desarrollo , Fenotipo , Polen/anatomía & histología , Polen/genética , Polen/crecimiento & desarrollo , Polen/fisiología , Semillas/anatomía & histología , Semillas/genética , Semillas/crecimiento & desarrollo , Semillas/fisiología , Avispas/fisiología
4.
Waste Manag ; 30(10): 1903-7, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20580543

RESUMEN

Mechanical biological treatment (MBT) of municipal solid waste (MSW) has become an important technology in waste management during the last decade. The paper compiles investigations of mechanical biological processes in Austrian MBT plants. Samples from all plants representing different stages of degradation were included in this study. The range of the relevant parameters characterizing the materials and their behavior, e.g. total organic carbon, total nitrogen, respiration activity and gas generation sum, was determined. The evolution of total carbon and nitrogen containing compounds was compared and related to process operation. The respiration activity decreases in most of the plants by about 90% of the initial values whereas the ammonium release is still ongoing at the end of the biological treatment. If the biogenic waste fraction is not separated, it favors humification in MBT materials that is not observed to such extent in MSW. The amount of organic carbon is about 15% dry matter at the end of the biological treatment.


Asunto(s)
Reactores Biológicos , Metano/biosíntesis , Eliminación de Residuos/métodos , Administración de Residuos/métodos , Amoníaco/metabolismo , Austria , Carbono/metabolismo , Sustancias Húmicas/análisis , Nitrógeno/metabolismo
5.
Waste Manag ; 30(4): 583-90, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19854633

RESUMEN

The Austrian Landfill Ordinance provides limit values regarding the reactivity for the disposal of mechanically biologically treated (MBT) waste before landfilling. The potential reactivity determined by biological tests according to the Austrian Standards (OENORM S 2027 1-2) can be underestimated if the microbial community is affected by environmental conditions. New analytical tools have been developed as an alternative to error-prone and time-consuming biological tests. Fourier Transform Infrared (FT-IR) spectroscopy in association with Partial Least Squares Regression (PLS-R) was used to predict the reactivity parameters respiration activity (RA(4)) and gas generation sum (GS(21)) as well as to detect errors resulting from inhibiting effects on biological tests. For this purpose 250 MBT-waste samples from different Austrian MBT-plants were investigated using FT-IR spectroscopy in the mid (MIR) and near infrared (NIR) area and biological tests. Spectroscopic results were compared with those from biological tests. Arising problems caused by interferences of RA(4) and GS(21) are discussed. It is shown that FT-IR spectroscopy predicts RA(4) and GS(21) reliably to assess stability of MBT-waste materials and to detect errors.


Asunto(s)
Monitoreo del Ambiente/métodos , Análisis Multivariante , Eliminación de Residuos , Residuos/análisis , Austria , Biodegradación Ambiental , Ciudades , Monitoreo del Ambiente/normas , Análisis de los Mínimos Cuadrados , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Espectroscopía Infrarroja por Transformada de Fourier
6.
Waste Manag ; 29(2): 859-68, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18782660

RESUMEN

The interaction of parameters determining the potential emissions of two different mechanically-biologically pretreated municipal solid wastes (MBT wastes) is elucidated in this work. The origins of the wastes are Germany and Sweden. By means of lab-scale experiments, increased stabilisation through composting is preferably determined by a decrease in respiration activity. Concurrently, the stabilisation is verified for the leachates by a decrease in COD, DOC, and BOD(5). Total organic carbon content reflects stabilisation less accurately. FT-IR and thermal analytical methods add valuable information about the state of degradation, especially when several distinct thermal parameters are taken into account. Mobility of Cr, Ni, Pb, and Zn produced by a batch leaching test with deionized water is reduced by the pretreatment of both materials. Mobility of copper unambiguously increased. A principle component analysis (PCA) of membrane fractionated leachates indicates an affinity of Cu to mobile humic acids or dissolved organic carbon. High Cr, Zn, and Ni contents in the solid co-occur with high contents of solid humic acids. To a lesser extent, this is also true for solid Cd, Cu, and Pb contents. Due to differences in required landfilling conditions, actual emissions and after-care phase length will depend on whether each waste is landfilled in Germany or Sweden.


Asunto(s)
Contaminantes Atmosféricos/química , Gases/química , Eliminación de Residuos/métodos , Suecia
7.
Bioresour Technol ; 100(5): 1775-80, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19010667

RESUMEN

Sewage sludge samples representing different stages during waste water and sewage sludge treatment were collected at four Austrian municipal waste water treatment plants. Changes of sludge composition are reflected by a specific infrared spectroscopic pattern. Anaerobically digested sludge was subjected to aeration in lab-scale reactors in order to find out if post-aeration after anaerobic digestion provides enhanced organic matter degradation and stabilization. Spectral data were evaluated by means of multivariate statistics. Similar spectral characteristics of sludge degradation stages were visualized by principal component analysis. The effect of additional aerobic treatment of anaerobically stabilized sludge was revealed by discriminant analysis that distinguishes additionally aerated sludge from all the other degradation stages of sludge because of changes in the spectral pattern by increasing stabilization. Based on partial least squares regression (PLSR) a correlation coefficient of R(2)=0.91 was found between spectral characteristics and the chemical oxygen demand (COD).


Asunto(s)
Bacterias Aerobias/metabolismo , Aguas del Alcantarillado/microbiología , Eliminación de Residuos Líquidos/métodos , Análisis Discriminante , Análisis Multivariante , Oxígeno/metabolismo , Análisis de Componente Principal , Análisis de Regresión , Espectrofotometría Infrarroja
8.
Appl Spectrosc ; 62(2): 190-6, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18284795

RESUMEN

The reproducibility of infrared spectra from different waste materials such as compost, mechanically-biologically treated (MBT) municipal solid waste, and landfill materials was investigated. Reproducibility tests focused mainly on infrared spectra and parameter prediction from the spectrum developed for composts and MBT-waste, as well as band height ratio measurement for landfill materials in terms of practical applications. Compared to compost and landfill material, the reproducibility of infrared spectra from MBT-waste was considerably lower. Accordingly, sample preparation was modified and maximum mean deviation was minimized from 8.3% to 4.2%. The number of required spectra replicates was determined in consideration of practical aspects such as parameter prediction for composts and MBT-waste and the measurement of band height ratios (2925/1630 cm(-1)) of landfill materials. For composts two-fold measurements and for MBT-waste and landfill materials three-fold measurements were considered appropriate.


Asunto(s)
Eliminación de Residuos , Suelo/análisis , Espectroscopía Infrarroja por Transformada de Fourier , Administración de Residuos/métodos , Biodegradación Ambiental , Ciudades , Monitoreo del Ambiente/métodos , Reproducibilidad de los Resultados
9.
Waste Manag ; 28(10): 1699-710, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-17890074

RESUMEN

Fourier transform infrared (FTIR) spectroscopy combined with multivariate data analysis is under development as a method to classify waste materials. The chemical composition of the sample is reflected by a series of regions of the infrared spectrum which are used as variables for multivariate data analysis. In this study, separated biowaste collection, mechanically-biologically treated waste (MBT-waste), and old landfill materials were collected to provide materials representing different stages of decomposition. A total of 819 FTIR absorbance spectra were recorded. Principal component analyses (PCA) were performed followed by soft independent modeling of class analogy (SIMCA) for classification of waste materials. Strong classification occurred for an analysis where spectral carbonate regions were included, and for another analysis when they were not. The SIMCA model enabled the differentiation and the classification of unknown samples according to the three categories in both cases. The classification methods developed here provide an assessment tool that regulatory authorities may wish to explore when assessing whether a treated waste from an uncertain process can be classed as compost or MBT-waste.


Asunto(s)
Residuos/clasificación , Modelos Teóricos , Análisis Multivariante , Análisis de Componente Principal , Espectroscopía Infrarroja por Transformada de Fourier , Residuos/análisis
10.
J Environ Monit ; 9(12): 1387-93, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18049778

RESUMEN

Five profiles of a 15-year-old bank containing over three weeks composted municipal solid waste were characterized by means of different parameters habitually applied in waste management (loss on ignition, total organic carbon, total nitrogen, NH(4)-N, pH), and in addition by humic acid determination, FTIR spectroscopy and thermal analysis. Stabilization processes are revealed by humic acid contents. Over the 15 year period organic matter had developed in various ways. Highest humic acid contents were found at 0.5 m below the surface. Below 1.0-1.5 m anaerobic conditions dominated causing a strong decline of humic acid concentrations. Despite similar contents of organic matter at 0.5 m and at 3.0 m organic matter quality differed. These differences were verified by infrared spectroscopic investigations and thermal analyses (differential scanning calorimetry DSC). The spectral pattern of 15-year-old profile samples (municipal solid waste including the biogenic fraction) was compared to current municipal solid waste and abandoned landfill materials. Current municipal solid waste samples comprised different degradation stages from fresh materials to stabilized waste, suitable for landfilling according to Austrian standards. Municipal solid waste originating from abandoned landfills closed in the seventies represented stable material. Principal component analysis was performed to detect similarities and differences. It is evident that the profile samples constitute a particular group in between municipal solid waste and abandoned landfill material. Some differences can be attributed to the divergent composition of municipal solid waste in the eighties when the organic fraction was not separated. Otherwise, landfill materials from the seventies with the same composition regarding the organic fraction were deposited together with construction waste. Heat flow curves (DSC profiles) of municipal solid waste, representing different decomposition stages, illustrate the development of enthalpies and reveal the status of the profile samples. It is evident that mechanical-biological pretreatment leads to a faster stabilization of waste organic matter.


Asunto(s)
Eliminación de Residuos , Rastreo Diferencial de Calorimetría , Sustancias Húmicas , Análisis de Componente Principal , Espectroscopía Infrarroja por Transformada de Fourier
11.
Water Sci Technol ; 53(8): 81-90, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16784192

RESUMEN

Further reduction of volatile suspended solids (VSS) during a post-stabilisation step was applied to evaluate the stabilisation degree of digested sewage sludge. For this purpose digested sludge was collected at four municipal wastewater treatment plants (WWTPs) and further stabilised in lab-scale chemostat reactors either under anaerobic or aerobic conditions. Experimental results showed that even in adequately digested sludge a consistent amount of VSS was degraded during aerobic post-stabilisation. It seems that aerobic conditions play a significant role during degradation of residual VSS. Additionally, specific VSS production (gVSS/peCOD110.d) as well as specific oxygen uptake rate were shown to be suitable parameters to assess the degree of sludge stabilisation at WWTPs. Fourier transform infrared spectroscopy was used to reveal changes in the sludge composition. Spectra of treated and untreated sludge samples indicated that the major component of residual VSS in stabilised sludge for instance consisted of biomass, while cellulose was absent.


Asunto(s)
Aguas del Alcantarillado/microbiología , Purificación del Agua/métodos , Aerobiosis , Anaerobiosis , Biodegradación Ambiental , Biomasa , Reactores Biológicos , Aguas del Alcantarillado/química , Espectroscopía Infrarroja por Transformada de Fourier
12.
Acta Vet Scand ; 35(2): 155-63, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7942381

RESUMEN

Field trials were carried out testing a new genetically engineered vaccine against Progressive Atrophic Rhinitis. The vaccine contained a non-toxic recombinant derivative of the P. multocida toxin. The experimental vaccine was compared with a commercial vaccine in 4 farms and in 1 farm 2 different dose regimens were applied. A total of 825 sows were included. The primary efficacy variable was a comparison of post mortem evaluation of the degree of conchae atrophy in the 4585 pigs. The pigs were slaughtered at normal slaughter weight. The secondary efficacy variables were serological response and age at slaughter. In all farms the experimental vaccine provided significantly better protection of the progeny than the control vaccine. The serological response in sows was significantly higher in all farms than the response to the control vaccine. The serological response did not differ between farms.


Asunto(s)
Proteínas Bacterianas , Vacunas Bacterianas , Pasteurella multocida/inmunología , Rinitis Atrófica/veterinaria , Enfermedades de los Porcinos/prevención & control , Animales , Animales Recién Nacidos , Toxinas Bacterianas/inmunología , Femenino , Rinitis Atrófica/prevención & control , Porcinos , Vacunas Sintéticas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...