Search results for "Lado"
showing 10 items of 323 documents
Modulador acusto-óptico en amplitud de fibra óptica basado en ondas acústicas de flexión
2014
Se reporta un estudio experimental de la operación de un modulador acusto-óptico (MAO) de fibra óptica basado en la interacción acusto-óptica producida por ondas acústicas de flexión estacionarias. Concentramos nuestra atención en los efectos de reducir el diámetro en la fibra óptica como mecanismo para optimizar la respuesta espectral del MAO. Como caso particular reportamos un modulador de 70 ¹m de diametro con una alta profundidad de modulación (60 %), bajas perdidas por inserción (1.3 dB) y un ancho ancho de banda a 3 dB de 40 nm que opera en el rango de los megahertz. Los resultados obtenidos demuestran que el incluir fibras estrechadas se puede considerar como un grado extra de libert…
Biological and microclimatic monitoring for conservation of cultural heritage: a case study at the De Rossi room of the Palatina library in Parma
2019
Biological particles in heritage-related indoor environments (museums, libraries, archives) represent a hazard to artifacts (biodeteriogenic action), operators and visitors’ health. The aim of the study was to evaluate environmental biological contamination and microclimate conditions in different periods of the year in De Rossi room of the historical Palatina Library in Parma. Microclimatic measurements were recorded continuously for a period ranging from 11 to 17 days in: January–February, May and September 2017. Monitoring of bacterial and fungal contamination was performed for air by active and passive sampling and by nitrocellulose membranes on shelves and manuscripts. Microorganisms w…
Climate variability and lake ecosystem responses in western Scandinavia (Norway) during the last Millennium
2017
This paper provides a high-resolution temperature reconstruction for the last Millennium from Lake Atnsjøen, SE Norway (61°52′31″N, 10°10′37″E). The sedimentary record reveals strong influence of the large-scale global climate patterns on the local climate in southern part of Eastern Norway. We reconstructed mean July air temperature using Chironomidae-based transfer function and fossil Chironomidae assemblages. The reconstruction was supported by a selection of climate-sensitive geochemical and paleoecological sedimentary proxies of terrestrial and aquatic origin, including Cladocera, pollen and macrofossils. Presented results revealed that summer temperatures were 1–2 °C warmer than the m…
The response of flood-plain ecosystems to the Late Glacial and Early Holocene hydrological changes: A case study from a small Central European river …
2016
Abstract We use a range of environmental variables to explore the possible drivers influencing the biota, especially the composition of aquatic invertebrates, during the Younger Dryas (YD) and Early Holocene (EH) in different river valley sites: a well-developed meandering river and the confluence zone of headwater streams. Using pollen, macrofossil, cladoceran, and chironomid as well as geochemical and lithological data as proxies for environmental factors (i.e., water depth and temperature), we attempt to show that these different sites display similar hydroclimatic signals (especially floods). The geochemical records in the studied valley are correlated with environmental factors, such a…
The response of a shallow lake and its catchment to Late Glacial climate changes — A case study from eastern Poland
2015
In this study we investigate how climate fluctuation in the Late Glacial period influenced the development of a lake and its catchment located in the East European Plain. We analyzed the sediments of the lake for pollen, subfossil Cladocera, macrofossils and chemical composition. We aimed at disentangling: (1) the climate changes and their limno-ecological responses, (2) temperature dynamics with the use of Cladocera-based transfer function (MJT) and macrofossil-based reconstruction of mean minimum July temperature (MMJT), (3) timing of the response of different proxies to environmental changes. The results of multiproxy analyses explicitly suggest that the main driver for changes in aquati…
Late Weichselian and Holocene record of the paleoenvironmental changes in a small river valley in Central Poland
2016
Abstract: The developmental history, from the Oldest Dryas to the Late Holocene, of a paleolake and mire located in a river valley in Central Poland was studied using high-resolution records of pollen, macrofossils, Cladocera, sedimentology, and geochemistry from a 14 C dated sediment core. We inferred temperature and water level dynamics using cladocerans and palynological and geochemical methods were employed to investigate natural fluvial activity, particularly for these elements that are difficult to find through sedimentological methods. Our research demonstrates how climate fluctuation in the Late Glacial and Holocene periods influenced the development of a paleolake and mire in a sma…
A multiproxy study of Younger Dryas and Early Holocene climatic conditions from the Grabia River paleo-oxbow lake (central Poland)
2015
International audience; A multi-proxy reconstruction of water depth, temperature and precipitation inferred from Cladocera, Chironomidae and pollen assemblages has been obtained from Świerczyna paleo-oxbow (central Poland) during the Younger Dryas (YD) and Early Holocene. Results suggest that the YD was relatively cold and comprised two main phases. The first (ca. 12,500–12,000 cal. yrs BP) is characterized by a continental climatic regime and a decrease in winter temperatures and precipitation but an increase in spring/summer precipitation. The second phase (ca. 12,000–11,500 cal. yrs BP) was more mild with a variable continental climate, an increase in summer and winter temperature, a len…
Trophic state changes can affect the importance of methane-derived carbon in aquatic food webs
2017
Methane-derived carbon, incorporated by methane-oxidizing bacteria, has been identified as a significant source of carbon in food webs of many lakes. By measuring the stable carbon isotopic composition (δ13C values) of particulate organic matter, Chironomidae andDaphniaspp. and their resting eggs (ephippia), we show that methane-derived carbon presently plays a relevant role in the food web of hypertrophic Lake De Waay, The Netherlands. Sediment geochemistry, diatom analyses and δ13C measurements of chironomid andDaphniaremains in the lake sediments indicate that oligotrophication and re-eutrophication of the lake during the twentieth century had a strong impact on in-lake oxygen availabili…
Effect of addition of Opuntia ficus-indica mucilage on the biological leavening, physical, nutritional, antioxidant and sensory aspects of bread
2019
The addition of active compounds to enhance the functional properties of foods is a quite common practice. Recently, bread became one of the target foods to incorporate functional ingredients such as those deriving from Opuntia spp. So far, only Opuntia ficus-indica cladodes in powder has been tested. The addition of fresh O. ficus-indica mucilage (in substitution to water) did not influence the biological leavening of the doughs. The resulting breads showed a biological role of the cactus mucilage, because their antioxidant activity was higher than that of control wheat bread. The sensory analysis indicated a general appreciation of the breads enriched with O. ficus-indica mucilage by the …
A Metabarcoding Survey on the Fungal Microbiota Associated to the Olive Fruit Fly.
2017
The occurrence of interaction between insects and fungi is interesting from an ecological point of view, particularly when these interactions involve insect pests and plant pathogens within an agroecosystem. In this study, we aimed to perform an accurate analysis on the fungal microbiota associated to Bactrocera oleae (Rossi) through a metabarcoding approach based on 454 pyrosequencing. From this analysis, we retrieved 43,549 reads that clustered into 128 operational taxonomic units (OTUs), of which 29 resulted in the “core” associate fungi of B. oleae. This fungal community was mainly represented by sooty mould fungi, such as Cladosporium spp., Alternaria spp. and Aureobasidium spp., by pl…