7,135 research outputs found
Feasibility experiments on time-resolved fluorosensing applied to oil slicks
The introduction of time resolved observations can provide a very penetrating tool in the practice of laser fluorosensing. The investigations have demonstrated a relevance of multispectral, time resolved analysis for oil fingerprinting. By comparative studies on a variety of crude oils and their most significant fractions, it was found that the process of time decay in a composite oil is characterized by a few steps, which are associated with specific components in the medium light range. The average decay times of these pure fractions are markedly differentiated as to absolute values and spectral spread; as a consequence, the corresponding parameters in the resultant crude are quite sensitive to the particular mixture of these components. Measurements of the time response give then a finer discrimination between oil classes, depending on the relative content of certain fractions. Experiments were pursued with an improved fluorosensor facility, in order to test the application of time resolved fluorosensing to remote samples on water
Alkane-grown Beauveria bassiana produce mycelial pellets displaying peroxisome proliferation, oxidative stress, and cell surface alterations
The entomopathogenic fungus Beauveria bassiana is able to grow on insect cuticle18 hydrocarbons as the sole carbon source, inducing several enzymes involved in alkane19 assimilation and concomitantly increasing virulence against insect hosts. In this study, we20 describe some physiological and molecular processes implicated in growth, nutritional21 stress response, and cellular alterations found in alkane-grown fungi. The fungal cytology22 was investigated using light and transmission electron microscopy (TEM) while the surface23 topography was examined using atomic force microscopy (AFM). Fungal hydrophobicity24 was also measured on the cell surface. Additionally, the expression pattern of several genes25 associated with oxidative stress, peroxisome biogenesis, and hydrophobicity were analysed26 by qPCR. We found a novel type of growth in alkane-cultured B. bassiana similar to27 mycelial pellets described in other alkane-free fungi, which were able to germinate and28 produce viable conidia in media without a carbon source and to be pathogenic against29 larvae of the beetles Tenebrio molitor and Tribolium castaneum. Optical microscopy and30 TEM showed that pellets were formed by hyphae cumulates with high peroxidase activity,31 exhibiting peroxisome proliferation and an apparent surface thickening. Alkane-grown32 conidia appeared to be more hydrophobic and cell surfaces displayed different topography33 than glucose-grown cells, as it was observed by AFM. We also found a significant34 induction in several genes encoding for peroxins, catalases, superoxide dismutases, and35 hydrophobins. These results show that both morphological and metabolic changes are36 triggered in mycelial pellets derived from alkane-grown B. bassiana.Fil: Huarte Bonnet, Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Santos Da Paixao, Flavia Regina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Ponce, Juan C. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Santana, Marianela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Prieto, Eduardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Pedrini, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; Argentin
Does player specialization predict player actions? Evidence from penalty kicks at FIFA World Cup and UEFA Euro Cup
Penalty-kicks are analysed in the literature as `real life experiments' for assessing the use of rational mixed strategies by professional players. However, each penalty kick cannot be considered a repetition of the same event because of the varying background conditions, in particular the heterogeneous ability of different players. Consequently, aggregate statistics over datasets composed of a large number of penalty kicks mediate the behaviour of the players in \emph{different} games, and the properties of optimal mixed strategies cannot be tested directly because of \emph{aggregation bias}. In this paper we model the heterogeneous ability of players. We then test the hypothesis that differently talented players randomise over different actions. To this aim, we study a dataset that collects penalties kicked during shootout series in the last editions of FIFA World-Cup and UEFA Euro-Cup (1994-2012) where kickers are categorized as specialists and non-specialists. The results support our theoretical prediction
Location of the Energy Levels of the Rare-Earth Ion in BaF2 and CdF2
The location of the energy levels of rare-earth (RE) elements in the energy
band diagram of BaF2 and CdF2 crystals is determined. The role of RE3+ and RE2+
ions in the capture of charge carriers, luminescence, and the formation of
radiation defects is evaluated. It is shown that the substantial difference in
the luminescence properties of BaF2:RE and CdF2:RE is associated with the
location of the excited energy levels in the band diagram of the crystals
Remotely sensed variables explain microhabitat selection and reveal buffering behaviours against warming in a climate-sensitive bird species
Fine-scale habitat selection modelling can allow a mechanistic understanding of habitat selection processes, enabling better assessments of the effects of climate and habitat changes on biodiversity. Remotely sensed data provide an ever-increasing amount of environmental and climatic variables at high spatio-temporal resolutions, and a unique opportunity to produce fine-scale habitat models particularly useful in challenging environments, such as high-elevation areas. Working at a 10-m spatial resolution, we assessed the value of remotely sensed data for investigating foraging habitat selection (in relation to topography, microclimate, land cover) in nestling-rearing white-winged snowfinch (Montifringilla nivalis), a high-elevation species highly sensitive to climate change. Adult snowfinches foraged at locations with intermediate vegetation cover and higher habitat heterogeneity, also avoiding extremely warm or extremely cold microclimates. Temperature interacted with other environmental drivers in defining habitat selection, highlighting trade-offs between habitat profitability and thermoregulation: snowfinches likely adopted mechanisms of behavioural buffering against physiologically stressful conditions by selecting for cooler, shaded and more snowy foraging grounds at higher temperatures. Our results matched those from previous studies based on accurate field measurements, confirming the species' reliance on climate-sensitive microhabitats (snow patches and low-sward grassland, in heterogeneous patches) and the usefulness of satellite-derived fine-scale modelling. Habitat suitability models built on remotely sensed predictors can provide a cost-effective method for periodic monitoring of species' habitats both at fine grain and over large extents. Fine-scale models also enhance our understanding of the actual drivers of (micro)habitat selection and of possible buffering behaviours against warming, allowing more accurate and robust distribution models, finer predictions of potential future changes and carefully targeted conservation strategies and habitat management
Invasive Crayfish moving Northwards: management challenges and policy implications at the local scale
Freshwater ecosystems in Italy, as most European countries, have been severely impacted by the invasion of alien crayfish. The two most widespread species in Trentino (NE Italy) are Procambarus clarkii and Faxionus limosus; for both species, the high elevation and cold climate of most of the Trentino territory represent a climatic barrier to their northwards spread. Procambarus clarkii is present in one small lake at 950 m asl, and Faxionus limosus in a group of 5 lakes at 450 m asl, over an area of about 80km2. the introduction of both species is associated with fish restocking, and lead to the extinction of existing populations of the native stone crayfish Austropotamobius pallipes. The Management Plan of Austropotamobius pallipes in Trentino listed the eradication/containment of these IAS populations among the conservation priorities for the native populations. The eradication campaigns of P. clarkii started in 2018 with a release/recapture campaign aimed at assessing the abundance of the populations, and continued in 2020, 2021, 2022. As a result, the capture efficiency decreased, suggesting a population reduction trend. The containment of Faxionus limosus is more difficult, given its presence in a higher number of lakes, three of which are hydrologically connected. A first containment campaign to prevent its spread in the river network is planned for summer 2023. The financial support to these activities has been granted by the local Nature 2000 networks and by the local administrations, which have also promoted the communication with citizens and stakeholders to raise consensus and collaboratio
Lignin degradation efficiency of chemical pre-treatments on banana rachis destined to bioethanol production
Valuable biomass conversion processes are highly dependent on the use of effective pretreatments for lignocellulose degradation and enzymes for saccharification. Among the nowadays available treatments, chemical delignification represents a promising alternative to physical-mechanical treatments. Banana is one of the most important fruit crops around the world. After harvesting, it generates large amounts of rachis, a lignocellulosic residue, that could be used for second generation ethanol production, via saccharification and fermentation. In the present study, eight chemical pretreatments for lignin degradation (organosolv based on organic solvents, sodium hypochlorite, hypochlorous acid, hydrogen peroxide, alkaline hydrogen peroxide, and some combinations thereof) have been tested on banana rachis and the effects evaluated in terms of lignin removal, material losses, and chemical composition of pretreated material. Pretreatment based on lignin oxidation have demonstrated to reach the highest delignification yield, also in terms of monosaccharides recovery. In fact, all the delignified samples were then saccharified with enzymes (cellulase and beta-glucosidase) and hydrolysis efficiency was evaluated in terms of final sugars recovery before fermentation. Analysis of Fourier transform infrared spectra (FTIR) has been carried out on treated samples, in order to better understand the structural effects of delignification on lignocellulose. Active chlorine oxidations, hypochlorous acid in particular, were the best effective for lignin removal obtaining in the meanwhile the most promising cellulose-to-glucose conversion
Localized versus itinerant magnetic moments in Na0.72CoO2
Based on experimental 59Co-NMR data in the temperature range between 0.1 and
300 K, we address the problem of the character of the Co 3d-electron based
magnetism in Na0.7CoO2. Temperature dependent 59Co-NMR spectra reveal different
Co environments below 300 K and their differentiation increases with decreasing
temperature. We show that the 23Na- and 59Co-NMR data may consistently be
interpreted by assuming that below room temperature the Co 3d-electrons are
itinerant. Their magnetic interaction appears to favor an antiferromagnetic
coupling, and we identify a substantial orbital contribution corb to the
d-electron susceptibility. At low temperatures corb seems to acquire some
temperature dependence, suggesting an increasing influence of spin-orbit
coupling. The temperature dependence of the spin-lattice relaxation rate
T1-1(T) confirms significant variations in the dynamics of this electronic
subsystem between 200 and 300K, as previously suggested. Below 200 K, Na0.7CoO2
may be viewed as a weak antiferromagnet with TN below 1 K but this scenario
still leaves a number of open questions.Comment: 8.7 pages, 6 Figures, submitted to Phys. Rev.
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