581 research outputs found

    Roberto Calasso - deconstructing mythology: a reading of Le nozze di Cadmo e Armonia

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    This thesis reviews Roberto Calasso’s Le nozze di Cadmo e Armonia (1988) and demonstrates that thematic and formal elements of this text allow us to to cast a postmodern and poststructuralist light on his theorization of ‘absolute literature’ – a declaration of faith in the power of literature which may appear to clash with the late twentieth century postmodern and poststructuralist climate responsible for concepts such as la mort de l’auteur. The importance of these findings lies in their going against Calasso’s claim that he never needed to use the word ‘postmodern’ and his complete silence on contemporary literary criticism, as well as on most contemporary authors. Calasso’s self-representation (interviews, criticism and the themes of the part-fictional work-in-progress) acknowledges as influences ancient Greek authors, both canonical and marginal; French dĂ©cadence; the finis Austriae; Marxism; Nietzsche; Hindu mythology and Aby Warburg. These influences are certainly at work in Le nozze, however they may be employed to subvert Calasso’s self-presentation. I have explored in detail the representations of literature emerging from Le nozze, and shown that they allow the identification in Calasso’s texts of elements confirming his fascination with poststructuralism, in particular with the thought of Jacques Derrida, despite the complete silence on this philosopher throughout Calasso’s work

    Magnetic properties of the frustrated AFM spinel ZnCr_2O_4 and the spin-glass Zn_{1-x}Cd_xCr_2O_4 (x=0.05,0.10)

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    The TT-dependence (2- 400 K) of the electron paramagnetic resonance (EPR), magnetic susceptibility, χ(T)\chi (T), and specific heat, Cv(T)C_{v}(T), of the normalnormal antiferromagnetic (AFM) spinel ZnCr2_{2}O4_{4} and the spin-glass (SG) Zn1−x_{1-x}Cdx_{x}Cr2_{2}O4_{4} (x=0.05,0.10x=0.05,0.10) is reported. These systems behave as a strongly frustrated AFM and SG with % T_{N} ≈TG≈12 \approx T_{G}\approx 12 K and -400 K ≳ΘCW≳−500\gtrsim \Theta_{CW}\gtrsim -500 K. At high-TT the EPR intensity follows the χ(T)\chi (T) and the gg-value is TT-independent. The linewidth broadens as the temperature is lowered, suggesting the existence of short range AFM correlations in the paramagnetic phase. For ZnCr2_{2}O4_{4} the EPR intensity and χ(T)\chi (T) decreases below 90 K and 50 K, respectively. These results are discussed in terms of nearest-neighbor Cr3+^{3+} (S =3/2=3/2%) spin-coupled pairs with an exchange coupling of ∣J/k∣≈| J/k| \approx 50 K. The appearance of small resonance modes for Tâ‰Č17T\lesssim 17 K, the observation of a sharp drop in χ(T)\chi (T) and a strong peak in Cv(T)C_{v}(T) at TN=12T_{N}=12 K confirms, as previously reported, the existence of long range AFM correlations in the low-TT phase. A comparison with recent neutron diffraction experiments that found a near dispersionless excitation at 4.5 meV for Tâ‰ČTNT\lesssim T_{N} and a continuous gapless spectrum for T≳TNT\gtrsim T_{N}, is also given.Comment: 17 pages, 8 figures, 1 Table. Submitted to Physical Review

    First-time lidar measurement of water vapor flux in a volcanic plume

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    The CO2 laser-based lidar ATLAS has been used to study the Stromboli volcano plume. ATLAS measured water vapor concentration in cross-sections of the plume and wind speed at the crater. Water vapor concentration and wind speed were retrieved by differential absorption lidar and correlation technique, respectively. Lidar returns were obtained up to a range of 3 km. The spatial resolution was 15 mand the temporal resolution was 20 s. By combining these measurements, the water vapor flux in the Stromboli volcano plume was found. To our knowledge, it is the first time that lidar retrieves water vapor concentrations in a volcanic plume.Published1295–12981.10. TTC - TelerilevamentoJCR Journalreserve

    The bridge volcanic LIdar-BILLI: A review of data collection and processing techniques in the Italian most hazardous volcanic areas

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    Volcanologists have demonstrated that carbon dioxide (CO2) fluxes are precursors of volcanic eruptions. Controlling volcanic gases and, in particular, the CO2 flux, is technically challenging, but we can retrieve useful information from magmatic/geological process studies for the mitigation of volcanic hazards including air traffic security. Existing techniques used to probe volcanic gas fluxes have severe limitations such as the requirement of near-vent in situ measurements, which is unsafe for operators and deleterious for equipment. In order to overcome these limitations, a novel range-resolved DIAL-Lidar (Differential Absorption Light Detection and Ranging) has been developed as part of the ERC (European Research Council) Project "BRIDGE", for sensitive, remote, and safe real-time CO2 observations. Here, we report on data collection, processing techniques, and the most significant findings of the experimental campaigns carried out at the most hazardous volcanic areas in Italy: Pozzuoli Solfatara (Phlegraen Fields), Stromboli, and Mt. Etna. The BrIdge voLcanic LIdar-BILLI has successfully obtained accurate measurements of in-plume CO2 concentration and flux. In addition, wind velocity has also been retrieved. It has been shown that the measurements of CO2 concentration performed by BILLI are comparable to those carried out by volcanologists with other standard techniques, heralding a new era in the observation of long-term volcanic gases

    Exchange bias effect in the phase separated Nd_{1-x}Sr_{x}CoO_3 at the spontaneous ferromagnetic/ferrimagnetic interface

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    We report the new results of exchange bias effect in Nd_{1-x}Sr_{x}CoO_3 for x = 0.20 and 0.40, where the exchange bias phenomenon is involved with the ferrimagnetic (FI) state in a spontaneously phase separated system. The zero-field cooled magnetization exhibits the FI (T_{FI}) and ferromagnetic (T_C) transitions at ~ 23 and \sim 70 K, respectively for x = 0.20. The negative horizontal and positive vertical shifts of the magnetic hysteresis loops are observed when the system is cooled through T_{FI} in presence of a positive static magnetic field. Training effect is observed for x = 0.20, which could be interpreted by a spin configurational relaxation model. The unidirectional shifts of the hysteresis loops as a function of temperature exhibit the absence of exchange bias above T_{FI} for x = 0.20. The analysis of the cooling field dependence of exchange bias field and magnetization indicates that the ferromagnetic (FM) clusters consist of single magnetic domain with average size around \sim 20 and ~ 40 \AA ~ for x = 0.20 and 0.40, respectively. The sizes of the FM clusters are close to the percolation threshold for x = 0.20, which grow and coalesce to form the bigger size for x = 0.40 resulting in a weak exchange bias effect.Comment: 9 pages, 9 figure

    Ambulatory surgery for perianal Crohn’s disease. Study of feasibility

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    Background. One-third of Crohn’s disease (CD) patients present perianal fistula. The gold standard in the diagnosis and treatment of symptomatic perianal disease (PAD) in CD is the exploration of the anal canal and distal rectum under anesthesia (EUA). This procedure is mainly conducted as a day case surgery. Unfortunately, it is not always possible to proceed within the ideal timing and any delay may well represent a relevant clinical issue. The aim of this study was to evaluate the feasibility of outpatient treatment of symptomatic perianal fistulas in CD patients. Methods. All CD patients under regular follow-up at our inflammatory bowel disease referral center, presenting with symptomatic perianal fistulas, were offered surgical consultation. The data of patients were prospectively collected for three years (February 2014 to February 2017) for the purpose of the study. All clinical information, including previous EUA and/or records from MRI and endoscopic ultrasound, was included. Outpatient anal canal and distal rectum exploration and treatment (OE) were undertaken during the specialist surgical consultation. Fistulas were classified according to Parks’s classification; the type of outpatient treatment and compliance of patients were recorded. Pain was assessed by VAS at the time of the procedure and during the first control. Patients were followed up in the surgical clinic in relation to the study. Results. Ninety-two CD patients with symptomatic perianal fistulas had surgical consultation during the study period. OE was offered to all but 18 patients who fulfilled the exclusion criteria or had an extremely severe disease; six patients refused the OE (8.11%). Of the 68 patients undergoing OE, eleven (16.18%) had previous surgery for perianal disease. The OE was accomplished in sixty-one patients (89.71%), while in 7 patients, it was abandoned for scarce compliance. Nine patients (14.75%) underwent drainage of perianal abscess; in 3 of them, it was possible to probe the fistula tract, find the internal orifice, and pass a loose seton. Overall, setonage was performed in 50 patients (81.97%). Rectovaginal setons were placed in 3 patients and more than one seton (up to 3) in 6 cases. Fistulotomy was performed in 4 simple subcutaneous fistulous tracts. Concordance with the preoperative findings was found in 54 out of 61 patients. EUA was scheduled at the time of OE for the 7 patients who did not complete the procedure. All sixty-one patients who had the OE were followed up for a minimum of 12 months. Conclusions. This preliminary study indicates that OE in CD patients with symptomatic perianal fistulas is safe and feasible in a high-volume referral center. It might provide several benefits, including patients’ logistics, reduce or remove patients’ symptoms and discomfort, allow for a timely start of medical therapy, and avoid further complications

    Laser remote sensing calibration of ocean color satellite data

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    world ocean: in fact, those processes dramatically affect the climatic equilibrium of our planet. For this reason, many advanced active and passive remote sensors have been used to study phytoplankton dynamics, since such phenomena are thought to be responsible for the sequestration of atmospheric carbon dioxide, one of the most important greenhouse gases. In this paper, one laser system and three satellite radiometers routinely used for the study of the phytoplankton dynamics will be briefly reviewed. Satellite sensors have been preferred to airborne sensors because, to our knowledge, ocean color airborne radiometers have not been operated in Antarctica, at least not throughout the whole lapse of time examined in this study. Particular focus was on the laser system (ELF) and on a specific satellite radiometer (SeaWiFS). ELF is based on the laser-induced fluorescence of phytoplankton pigments and was conceived for the Italian expeditions to Antarctica. The goal of SeaWiFS is to provide the Earth science community with quantitative data on the global ocean bio-optical properties. Such satellite radiometer has been calibrated with in situ data mainly acquired in non polar regions. This is why a comparison between ELF and SeaWiFS measurements of chlorophyll-a surface concentrations in the Southern Ocean during the austral summer 1997-1998 was believed to be significant. Our results indicate that SeaWiFS overestimates high concentrations and underestimates low concentrations. In order to correct this behavior, the chlorophyll- a bio-optical algorithm of SeaWiFS has been recalibrated according to the measurements of ELF, thus providing a new estimation of the primary production in the Southern Ocean

    Particle size dependence of the magnetic properties of ultrafine granular films

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    Magnetic granular solids consist of ultrafine metal granules of nanometer sizes embedded in an insulating medium. The magnetic properties are dictated by the microstructure such as particle size, metal volume fraction, which are process controlled. We report the results of a series of granular Fe60(SiO2)40 films in which the particle size has been systematically varied. The magnetic coercivity, ranging from 500 to 2200 Oe, increases with particle size. The ferromagnetic-superparamagnetic transition had been studied by SQUID magnetometry and Mössbauer spectroscopy. The value of the magnetic anisotropy energy is found to be much larger than that due to magnetocrystalline anisotropy

    . New ground-based lidar enables volcanic CO2 flux measurements

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    There have been substantial advances in the ability to monitor the activity of hazardous volcanoes in recent decades. However, obtaining early warning of eruptions remains challenging, because the patterns and consequences of volcanic unrests are both complex and nonlinear. Measuring volcanic gases has long been a key aspect of volcano monitoring since these mobile fluids should reach the surface long before the magma. There has been considerable progress in methods for remote and in-situ gas sensing, but measuring the flux of volcanic CO2—the most reliable gas precursor to an eruption—has remained a challenge. Here we report on the first direct quantitative measurements of the volcanic CO2 flux using a newly designed differential absorption lidar (DIAL), which were performed at the restless Campi Flegrei volcano. We show that DIAL makes it possible to remotely obtain volcanic CO2 flux time series with a high temporal resolution (tens of minutes) and accuracy (<30%). The ability of this lidar to remotely sense volcanic CO2 represents a major step forward in volcano monitoring, and will contribute improved volcanic CO2 flux inventories. Our results also demonstrate the unusually strong degassing behavior of Campi Flegrei fumaroles in the current ongoing state of unrest
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