115 research outputs found
Il testo ‘secondo’: verso una tipologia delle trasformazioni testuali
No full textIl Medio Evo è un periodo caratterizzato da un forte sperimentalismo letterario e da una duttilità testuale che consente con straordinaria facilità la trasformazione del testo d’un’opera nei testi di nuove opere. L’autore individua e illustra quattro forme principali di queste trasformazioni: 1) la traduzione; 2) la riformulazione; 3) il montaggio e 4) l’infiorescenza. In ognuna di queste forme sono distinguibili ulteriori sottotipi di avatar letterarî, a volte molto importanti, come i seguenti: stesura, redazione, rimaneggiamento, rifacimento, adattamento, pastiche, ciclizzazione, spin-off, reboots e altri ancora.The Middle Ages are a time characterized by strong literary experimentation and textual plasticity allowing for an extraordinary ease in transforming the text from a literary work into further texts of other works. The author identifies and shows the four main types of transformation: 1) translation; 2) reformulation; 3) editing and 4) inflorescence. Within each of these types, further subtypes of literary avatars can be found, sometimes very important ones, such as drawing up, drafting, rehashing, remaking, adapting, pastiche, serialization, spin-off, reboots and more
Potentialities of the microbial consortium Curvularia kusanoi -Trichoderma pleuroticola as a biological pretreatment for the degradation of fibrous sources
No full textObjective. To evaluate the potentiality of the microbial consortium Curvularia kusanoi L7- Trichoderma pleuroticola as biological pretreatment of high fiber sources destined for animal production. Materials and methods. The Strains used where Curvularia kusanoi L7 and Trichoderma pleuroticola. The degradative potential was evaluated through the production kinetics of cellulolytic (endo-1,4-β-glucanase and exo-1,4-β-glucanase) and ligninolytics enzymes (laccase and peroxidase) in solid submerged fermentation of bran wheat and sugarcane bagasse. The growth of the co culture in plates was analyzed. The effect of the consortium on the carbon mineralization of raw wheat straw was determined and the degree of fiber degradation was evaluated by infrared spectroscopy (IR). Resulted. Both strains showed high cellulolytic production. Only C. kusanoi L7 showed ligninolytic activity, with a maximum laccase activity of 1400 U / L. No antagonism was found between the strains and the results of carbon mineralization and evaluation of their final products by IR indicate the effectiveness of the consortium to degrade the cell wall more efficiently than each of the strains individually. Conclusions. It is concluded that the microbial consortium C. kusanoi L7-T. pleuroticola has great potential for structural modification of fibrous sources destined for animal feeding.Objetivo. Evaluar la potencialidad del consorcio microbiano Curvularia kusanoi L7- Trichoderma pleuroticola como método biológico de pretratamiento de alimentos altos en fibra destinados a la producción animal. Materiales y métodos. Se utilizaron las cepas Curvularia kusanoi L7 y Trichoderma pleuroticola. Se evaluó el potencial degradativo a través de las cinéticas de producción de las enzimas celulolítica (endo-1,4-β- glucanasa y exo-1,4-β- glucanasa) y ligninolíticas (lacasa y peroxidasa) en fermentación sólido sumergido de salvado de trigo y de bagazo de caña de azúcar. Se analizó el crecimiento del cocultivo en placas. Se determinó el efecto del consorcio sobre la mineralización del carbono de la paja de trigo cruda y se evaluó el grado de degradación de la fibra por espectroscopía infrarroja (IR). Resultados. Ambas cepas mostraron alta producción celulolítica . Solo C. kusanoi L7 mostró actividad ligninolítica, con actividad lacasa máxima de 1400 U/L. No se encontró antagonismo entre las cepas y los resultados de mineralización del carbono y evaluación de sus productos finales mediante IR, indican la efectividad del consorcio para degradar la pared celular de forma más eficiente que cada una de las cepas de manera individual. Conclusiones. Se concluye que el consorcio microbiano C. kusanoi L7-T.pleuroticola presenta grandes potencialidades para emplearse en la modificación estructural de fuentes fibrosas destinadas a la alimentación animal
Environmental Conditions Modulate Warming Effects on Plant Litter Decomposition Globally
No full textEmpirical studies worldwide show that warming has variable effects on plant litter decomposition, leaving the overall impact of climate change on decomposition uncertain. We conducted a meta-analysis of 109 experimental warming studies across seven continents, using natural and standardised plant material, to assess the overarching effect of warming on litter decomposition and identify potential moderating factors. We determined that at least 5.2 degrees of warming is required for a significant increase in decomposition. Overall, warming did not have a significant effect on decomposition at a global scale. However, we found that warming reduced decomposition in warmer, low-moisture areas, while it slightly increased decomposition in colder regions, although this increase was not significant. This is particularly relevant given the past decade's global warming trend at higher latitudes where a large proportion of terrestrial carbon is stored. Future changes in vegetation towards plants with lower litter quality, which we show were likely to be more sensitive to warming, could increase carbon release and reduce the amount of organic matter building up in the soil. Our findings highlight how the interplay between warming, environmental conditions, and litter characteristics improves predictions of warming's impact on ecosystem processes, emphasising the importance of considering context-specific factors
Erratum: Search for photons with energies above 1018 eV using the hybrid detector of the Pierre Auger Observatory
No full textExposure calculation Due to a mistake in the numerical integration following eq. (6.2) of the original article [1], the exposure shown in figure 5 of the original article was incorrect. The correct exposure is shown in figure 1. 2 Upper limits on the integral photon flux and fraction The incorrect exposure affects the calculation of the upper limits on the integral photon flux following eq. (6.1) of the original article. The correct values for the upper limits are 0.038, 0.010, 0.009, 0.008 and 0.007 km−2 sr−1 yr−1 for threshold energies of 1, 2, 3, 5 and 10 EeV. The correct values for the upper limits on the integral photon fraction subsequently derived are 0.14 %, 0.17 %, 0.42 %, 0.86 % and 2.9 % for the same threshold energies. 3 Author list The author list of this erratum also corrects a mistake made in the original article, where F. Zuccarello was missing and Z. Zong was listed twice
Evidence for a mixed mass composition at the ‘ankle’ in the cosmic-ray spectrum
No full textWe report a first measurement for ultrahigh energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the ‘ankle’ at lg(E/eV)=18.5–19.0lg(E/eV)=18.5–19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4A>4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavored as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth
Depth of maximum of air-shower profiles at the Pierre Auger Observatory. I. Measurements at energies above 1017.8eV
No full textWe report a study of the distributions of the depth of maximum, X-max, of extensive air-shower profiles with energies above 10(17.8) eV as observed with the fluorescence telescopes of the Pierre Auger Observatory. The analysis method for selecting a data sample with minimal sampling bias is described in detail as well as the experimental cross-checks and systematic uncertainties. Furthermore, we discuss the detector acceptance and the resolution of the X-max measurement and provide parametrizations thereof as a function of energy. The energy dependence of the mean and standard deviation of the X-max distributions are compared to air-shower simulations for different nuclear primaries and interpreted in terms of the mean and variance of the logarithmic mass distribution at the top of the atmosphere
Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 × 1018 eV
No full textCosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come from studying the distribution of their arrival directions. Using 3 × 104 cosmic rays with energies above 8 × 1018 electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 km2 sr year, we determined the existence of anisotropy in arrival directions. The anisotropy, detected at more than a 5.2σ level of significance, can be described by a dipole with an amplitude of Embedded Image percent toward right ascension αd = 100 ± 10 degrees and declination δd = Embedded Image degrees. That direction indicates an extragalactic origin for these ultrahigh-energy particles
Muons in air showers at the Pierre Auger Observatory : Measurement of atmospheric production depth
No full text15 pages, 9 figures, accepted for publication in Physical Review D ; see paper for full list of authorsInternational audienceThe surface detector array of the Pierre Auger Observatory provides information about the longitudinal development of the muonic component of extensive air showers. Using the timing information from the flash analog-to-digital converter traces of surface detectors far from the shower core, it is possible to reconstruct a muon production depth distribution. We characterize the goodness of this reconstruction for zenith angles around 60 deg. and different energies of the primary particle. From these distributions we define X(mu)max as the depth along the shower axis where the production of muons reaches maximum. We explore the potentiality of X(mu)max as a useful observable to infer the mass composition of ultrahigh-energy cosmic rays. Likewise, we assess its ability to constrain hadronic interaction models
Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory
No full textWe report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to 80°and energies in excess of 4 EeV (4 à 1018eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providing directional information on any observed anisotropies. No deviation from isotropy is observed on any angular scale in the energy range between 4 and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured; while no other deviation from isotropy is observed for moments beyond the dipole one. The corresponding p-values obtained after accounting for searches blindly performed at several angular scales, are 1.3 à 10-5in the case of the angular power spectrum, and 2.5 à 10-3in the case of the needlet analysis. While these results are consistent with previous reports making use of the same data set, they provide extensions of the previous works through the thorough scans of the angular scales
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