Beyond the tree of texts: Building an empirical model of scribal variation through graph analysis of texts and stemmata

Stemmatology, or the reconstruction of the transmission history of texts, is a field that stands particularly to gain from digital methods. Many scholars already take stemmatic approaches that rely heavily on computational analysis of the collated text (e.g. Robinson and O’Hara 1996; Salemans 2000; Heikkilä 2005; Windram et al. 2008 among many others). Although there is great value in computationally assisted stemmatology, providing as it does a reproducible result and allowing access to the relevant methodological process in related fields such as evolutionary biology, computational stemmatics is not without its critics. The current state-of-the-art effectively forces scholars to choose between a preconceived judgment of the significance of textual differences (the Lachmannian or neo-Lachmannian approach, and the weighted phylogenetic approach) or to make no judgment at all (the unweighted phylogenetic approach). Some basis for judgment of the significance of variation is sorely needed for medieval text criticism in particular. By this, we mean that there is a need for a statistical empirical profile of the text-genealogical significance of the different sorts of variation in different sorts of medieval texts. The rules that apply to copies of Greek and Latin classics may not apply to copies of medieval Dutch story collections; the practices of copying authoritative texts such as the Bible will most likely have been different from the practices of copying the Lives of local saints and other commonly adapted texts. It is nevertheless imperative that we have a consistent, flexible, and analytically tractable model for capturing these phenomena of transmission. In this article, we present a computational model that captures most of the phenomena of text variation, and a method for analysis of one or more stemma hypotheses against the variation model. We apply this method to three ‘artificial traditions’ (i.e. texts copied under laboratory conditions by scholars to study the properties of text variation) and four genuine medieval traditions whose transmission history is known or deduced in varying degrees. Although our findings are necessarily limited by the small number of texts at our disposal, we demonstrate here some of the wide variety of calculations that can be made using our model. Certain of our results call sharply into question the utility of excluding ‘trivial’ variation such as orthographic and spelling changes from stemmatic analysis.

Psoriasis beyond the skin: an expert group consensus on the management of psoriatic arthritis and common co-morbidities in patients with moderate-to-severe psoriasis

BACKGROUND Psoriatic arthritis (PsA) and co-morbidities of psoriasis represent a significant clinical and economic burden for patients with moderate-to-severe psoriasis. Often these co-morbidities may go unrecognized or undertreated. While published data are available on the incidence and impact of some of them, practical guidance for dermatologists on detection and management of these co-morbidities is lacking. OBJECTIVE To prepare expert recommendations to improve the detection and management of common co-morbidities in patients with moderate-to-severe psoriasis. METHODS A systematic literature review was conducted on some common co-morbidities of psoriasis-cardiovascular (CV) diseases (including obesity, hypertension, hyperglycaemia and dyslipidaemia), psychological co-morbidities (including depression, alcohol abuse and smoking) and PsA-to establish the incidence and impact of each. Data gaps were identified and a Delphi survey was carried out to obtain consensus on the detection and management of each co-morbidity. The expert panel members for the Delphi survey comprised 10 dermatologists with substantial clinical expertise in managing moderate-to-severe psoriasis patients, as well as a cardiologist and a psychologist (see appendix) with an interest in dermatology. Agreement was defined using a Likert scale of 1-7. Consensus regarding agreement for each statement was defined as ≥75% of respondents scoring either 1 (strongly agree) or 2 (agree). RESULTS The expert panel members addressed several topics including screening, intervention, monitoring frequency, and the effects of anti-psoriatic treatment on each co-morbidity. Consensus was achieved on 12 statements out of 22 (3 relating to PsA, 4 relating to psychological factors, 5 relating to CV factors). The panel members felt that dermatologists have an important role in screening their psoriasis patients for PsA and in assessing them for psychological and CV co-morbidities. In most cases, however, patients should be referred for specialist management if other co-morbidities are detected. CONCLUSION This article provides useful and practical guidance for the detection and management of common co-morbidities in patients with moderate-to-severe psoriasis.

Space-qualified laser system for the BepiColombo Laser Altimeter

The space-qualified design of a miniaturized laser for pulsed operation at a wavelength of 1064 nm and at repetition rates up to 10 Hz is presented. This laser consists of a pair of diode-laser pumped, actively q-switched Nd:YAG rod oscillators hermetically sealed and encapsulated in an environment of dry synthetic air. The system delivers at least 300 million laser pulses with 50 mJ energy and 5 ns pulse width (FWHM). It will be launched in 2017 aboard European Space Agency’s Mercury Planetary Orbiter as part of the BepiColombo Laser Altimeter, which, after a 6-years cruise, will start recording topographic data from orbital altitudes between 400 and 1500 km above Mercury’s surface.

Measurement of the neutrino velocity with the OPERA detector in the CNGS beam using the 2012 dedicated data

In spring 2012 CERN provided two weeks of a short bunch proton beam dedicated to the neutrino velocity measurement over a distance of 730 km. The OPERA neutrino experiment at the underground Gran Sasso Laboratory used an upgraded setup compared to the 2011 measurements, improving the measurement time accuracy. An independent timing system based on the Resistive Plate Chambers was exploited providing a time accuracy of ∼1 ns. Neutrino and anti-neutrino contributions were separated using the information provided by the OPERA magnetic spectrometers. The new analysis profited from the precision geodesy measurements of the neutrino baseline and of the CNGS/LNGS clock synchronization. The neutrino arrival time with respect to the one computed assuming the speed of light in vacuum is found to be δtν≡TOFc−TOFν=(0.6±0.4 (stat.)±3.0 (syst.)) ns and δtν¯≡TOFc−TOFν¯=(1.7±1.4 (stat.)±3.1 (syst.)) ns for νμ and ν¯μ, respectively. This corresponds to a limit on the muon neutrino velocity with respect to the speed of light of −1.8×10−6<(vν−c)/c<2.3×10−6 at 90% C.L. This new measurement confirms with higher accuracy the revised OPERA result.