Three-years of SO2 flux measurements of Mt. Etna using an automated UV scanner array: comparison with conventional traverses and uncertainties in flux retrieval

Routine measurements of SO2 flux using the traverse method on Mt. Etna (Italy) were augmented in late 2004 when an array of automatic scanning ultraviolet spectrometers was installed. Each instrument allows one SO2 scan to be recorded every ~6 min. Here we report the methods that we developed to automatically and robustly transform SO2 profiles into SO2 flux data. Radian geometry and Fast Fourier Transform algorithm were used for reducing plume cross sections and for discriminating between volcanic plumes from those produced by water vapour clouds. Uncertainty in flux measurements depends on the accuracy of plume-height estimation, on assumptions concerning plume-geometry, and on the quality of the retrieved SO2 amounts. We compare 3 years of flux measurements made using both the automated network and “conventional” traverse methods beneath the plume. We found a good agreement between the datasets, both in terms of magnitude and in temporal variations. These results validate the Etna SO2 flux monitoring system. Emission rates are available to the 24-hour manned operations room via intranet, providing real-time information on degassing rates and plume location

Reply to comment from Liotta and Rizzo on “Evolution of CO2 , SO2 , HCl and HNO3 in the volcanic plumes from Etna” by Voigt et al. [Geophys. Res. Lett.; 41, doi:10.1002/2013GL058974]

Editor’s Note: The following comment and reply arise from an article published in Geophysical Research Letters by Voigt et al. (2014). The article addresses a volcanology topic, and the commenters take issue with some conclusions and offer an analysis of their own. Voigt and co-authors have responded. Why is this comment-and-reply being published in the Bulletin? It is because Geophysical Research Letters is one of a number of journals that do not offer any published forum for discussion of the papers they publish. This is a matter of editorial policy and a decision for each journal. The Bulletin of Volcanology does provide a forum for discussion of articles published. When contacted by Marcello Liotta with the request that the Bulletin consider hosting a discussion of the Voigt et al. volcanology article in GRL, I agreed to do so if the GRL authors were willing to engage with the comment. Voigt and co-authors were willing to do so and have been allowed a small amount of additional space to summarize for Bulletin readers the key points of the GRL paper under discussion before responding directly to the comment from Liotta and Rizzo. I hope that Bulletin readers find the discussion and reply of interest

Modulational instability in cigar shaped Bose-Einstein condensates in optical lattices

A self consistent theory of a cigar shaped Bose-Einstein condensate (BEC) periodically modulated by a laser beam is presented. We show, both theoretically and numerically, that modulational instability/stability is the mechanism by which wavefunctions of soliton type can be generated in cigar shaped BEC subject to a 1D optical lattice. The theory explains why bright solitons can exist in BEC with positive scattering length and why condensate with negative scattering length can be stable and give rise to dark solitary pulses.Comment: Submitted, 4 pages, 3 figures. Revised versio

Novel retrieval of volcanic SO2 abundance from ultraviolet spectra

The recent development of fixed networks of scanning ultraviolet spectrometers for automatic determination of volcanic SO2 fluxes has created tremendous opportunities for monitoring volcanoes but has brought new challenges in processing of the substantial data flow they produce. A particular difficulty in standard implantation of differential optical absorption (DOAS) methods is the requirement for a clear-sky (plume-free) background spectrum. Our experience after four years of measurements with two UV scanner networks on Etna and Stromboli shows that wide plumes are frequently observed precluding simple selection of clear-sky spectra. We have therefore developed a retrieval approach based on simulation of the background spectrum. We describe the method here and tune it empirically by collecting clear, zenith sky spectra using calibration cells containing known amounts of SO2. We then test the performance of this optimised retrieval using clear-sky spectra collected with the same calibration cells but for variable scan angles, time of day, and season (through the course of 1 year). We find in all cases acceptable results (maximum ~12% error) for SO2 column amounts. The method is therefore very suitable for automated SO2-plume monitoring

Monopoly as a ‘culture-history fact’: Knight, Menger, and the role of institutions

Frank Knight's theory of monopoly price has received relatively little attention in the literature on Risk, Uncertainty and Profit. We argue that Knight accepted and refined the monopoly price theory of Carl Menger and his followers. Knight highlights the difference between monopoly as an inevitable outcome of departures from perfect competition, and monopoly as a contingent or ‘culture-history fact’. In the latter case, coercive institutional barriers to potential competition shape the choice set of consumers and producers, and provide a crucial method for identifying monopoly gains. There are three benefits to this account of Knight's contributions: it rehabilitates the focus on the institutional determinants of monopoly price, as opposed to the mainstream emphasis on market frictions and imperfections; it opens the way for a Mengerian monopoly price theory that seriously engages the study of institutions; and it adds new evidence and nuance to ongoing debates about Knight's place in economics

The influence of a Juvenile\u27s Abuse History on Support for Sex Offender Registration

We investigated whether and how a juvenile’s history of experiencing sexual abuse affects public perceptions of juvenile sex offenders in a series of 5 studies. When asked about juvenile sex offenders in an abstract manner (Studies 1 and 2), the more participants (community members and undergraduates) believed that a history of being sexually abused as a child causes later sexually abusive behavior, the less likely they were to support sex offender registration for juveniles. Yet when participants considered specific sexual offenses, a juvenile’s history of sexual abuse was not considered to be a mitigating factor. This was true when participants considered a severe sexual offense (forced rape; Study 3 and Study 4) and a case involving less severe sexual offenses (i.e., statutory rape), when a juvenile’s history of sexual abuse backfired and was used as an aggravating factor, increasing support for registering the offender (Study 3 and Study 5). Theoretical and practical implications of these results are discussed

Executive functioning in preschool children affected by autism spectrum disorder: A pilot study

Introduction: Autism spectrum disorders (ASD) are a complex set of neurological dysfunction and development characterized by deficits in social and non-verbal interaction. Few studies have explored the executive functioning in ASD preschoolers. The aim of this pilot study is the assessment of executive functioning in preschool children with ASD. Material and methods: 8 ASD children (7 males, 1 female) mean age 3.09 (SD \ub1 0.83 years) were enrolled in the study and compared with a control group of 15 typically developing children (12 males, 3 females) (mean age 24.3 \ub1 0.61). All subjects underwent assessment of executive functioning with the BRIEF-P test. Results: The two groups were matched for age (p = 0.625) and gender (p = 0.900). Table 1 shows the comparison between the two groups at the BRIEF-P, with significantly higher scores on all subscales of ASD children compared with controls. Conclusions: Despite the small sample examined the results of this study agree with what is already known in the literature confirm the presence of a significant deficit in executive functions of subjects with ASD emphasizing for the first time the emergence of such problems at an early stage of development, but demanding further studies to confirm this

Exact eigenspectrum of the symmetric simple exclusion process on the complete, complete bipartite, and related graphs

We show that the infinitesimal generator of the symmetric simple exclusion process, recast as a quantum spin-1/2 ferromagnetic Heisenberg model, can be solved by elementary techniques on the complete, complete bipartite, and related multipartite graphs. Some of the resulting infinitesimal generators are formally identical to homogeneous as well as mixed higher spins models. The degeneracies of the eigenspectra are described in detail, and the Clebsch-Gordan machinery needed to deal with arbitrary spin-s representations of the SU(2) is briefly developed. We mention in passing how our results fit within the related questions of a ferromagnetic ordering of energy levels and a conjecture according to which the spectral gaps of the random walk and the interchange process on finite simple graphs must be equal.Comment: Final version as published, 19 pages, 4 figures, 40 references given in full forma

Phase diagram of two-lane driven diffusive systems

We consider a large class of two-lane driven diffusive systems in contact with reservoirs at their boundaries and develop a stability analysis as a method to derive the phase diagrams of such systems. We illustrate the method by deriving phase diagrams for the asymmetric exclusion process coupled to various second lanes: a diffusive lane; an asymmetric exclusion process with advection in the same direction as the first lane, and an asymmetric exclusion process with advection in the opposite direction. The competing currents on the two lanes naturally lead to a very rich phenomenology and we find a variety of phase diagrams. It is shown that the stability analysis is equivalent to an `extremal current principle' for the total current in the two lanes. We also point to classes of models where both the stability analysis and the extremal current principle fail