Massless particles on supergroups and AdS3 x S3 supergravity

Firstly, we study the state space of a massless particle on a supergroup with a reparameterization invariant action. After gauge fixing the reparameterization invariance, we compute the physical state space through the BRST cohomology and show that the quadratic Casimir Hamiltonian becomes diagonalizable in cohomology. We illustrate the general mechanism in detail in the example of a supergroup target GL(1|1). The space of physical states remains an indecomposable infinite dimensional representation of the space-time supersymmetry algebra. Secondly, we show how the full string BRST cohomology in the particle limit of string theory on AdS3 x S3 renders the quadratic Casimir diagonalizable, and reduces the Hilbert space to finite dimensional representations of the space-time supersymmetry algebra (after analytic continuation). Our analysis provides an efficient way to calculate the Kaluza-Klein spectrum for supergravity on AdS3 x S3. It may also be a step towards the identification of an interesting and simpler subsector of logarithmic supergroup conformal field theories, relevant to string theory.Comment: 16 pages, 10 figure

Guidance on Design and Construction of the Built Environment Against Wildland Urban Interface Fire Hazard: A Review

Wildland-Urban Interface (WUI) fires, a worldwide problem, are gaining more importance over time due to climate change and increased urbanization in WUI areas. Some jurisdictions have provided standards, codes and guidelines, which may greatly help planning, prevention and protection against wildfires. This work presents a wide systematic review of standards, codes and guidelines for the design and construction of the built environment against WUI fire hazard from North American, European, Oceanic countries, alongside with trans-national codes. The main information reviewed includes: the definition of WUI hazards, risk areas and related severity classes, the influence of land and environmental factors, the requirements for building materials, constructions, utilities, fire protection measures and road access. Some common threads among the documents reviewed have been highlighted. They include similar attempts at: (a) defining WUI risk areas and severity classes, (b) considering land factors including the defensible space (also known as ignition zones), (c) prescribing requirements for buildings and access. The main gaps highlighted in the existing standards/guidelines include lacks of detailed and widespread requirements for resources, fire protection measures, and lacks of taking into account environmental factors in detail. The main design and construction principles contained in the reviewed documents are largely based on previous research and/or good practices. Hence, the main contributions of this paper consist in: (a) systematically disseminate these guidance concepts, (b) setting a potential basis for the development of standards/guidelines in other jurisdictions lacking dedicated WUI fire design guidance, (c) highlighting gaps in existing standards/guidelines to be addressed by current and future research

How do paediatricians use and monitor antithyroid drugs in the UK? A clinician survey

Objective We aimed to document current practice in the medical management of paediatric hyperthyroidism in the UK and compare to international recommendations. Design A 27‐question online survey distributed via an electronic newsletter in August 2018. Participants Responses from 48 members (11%) of the British Society for Paediatric Endocrinology and Diabetes. Measurements Information about antithyroid drug (ATD) preference, treatment duration, monitoring of full blood count (FBC), management of neutropaenia, agranulocytosis screening and patient education. Results Carbimazole is favoured by 98% of respondents and a “dose titration” regimen preferred over “block and replace” (65% vs 29%). TRAbs (thyroid‐stimulating hormone receptor antibodies) are used for diagnostic purposes by 85% and by 33% to look for evidence of disease remission. The majority (81%) treat for a minimum of 2 years before considering a trial off ATD. All respondents reported that they “always/usually” warn their patients about the risk of agranulocytosis before starting ATD, but written information is “rarely/never” provided by 63%. Sore throat (98%) and fever (92%) are the most commonly cited symptoms used to alert a patient to possible agranulocytosis. FBC is measured prior to treatment by 65% and measured periodically during treatment by 70%. Conclusions The management of paediatric hyperthyroidism with ATDs in the UK is not consistent with all international recommendations because a block and replace ATD regimen remains widely used. TRAbs are utilized at presentation, but underused for detecting disease remission. National consensus guidelines and written patient information may refine the management of paediatric patients on ATDs

First-principles derivation of the AdS/CFT Y-systems

We provide a first-principles, perturbative derivation of the AdS5/CFT4 Y-system that has been proposed to solve the spectrum problem of N=4 SYM. The proof relies on the computation of quantum effects in the fusion of some loop operators, namely the transfer matrices. More precisely we show that the leading quantum corrections in the fusion of transfer matrices induce the correct shifts of the spectral parameter in the T-system. As intermediate steps we study UV divergences in line operators up to first order and compute the fusion of line operators up to second order for the pure spinor string in AdS5xS5. We also argue that the derivation can be easily extended to other integrable models, some of which describe string theory on AdS4, AdS3 and AdS2 spacetimes.Comment: 45 pages, 5 figures; v2: minor additions, JHEP versio

Morphological, physiological and pathogenic variability of small-spore Alternaria sp. causing leaf blight of Solanaceous plants in Algeria

Due to premature defoliation, early blight epidemics can cause major yield losses. Large-spore Alternaria species such as A. solani and A. tomatophila have long been recognized as important pathogens responsible for such blight disease in the family Solanaceae and thus represent a serious risk for crop production. Small-spore Alternaria species have also been frequently isolated from plant samples with typical blight symptoms but their incidence as primary pathogens is often controversial. In order to study the diversity of small-spore Alternaria species, 32 isolates were selected from a larger collection of 130 isolates from infected leaves, fruits and stems of tomato from various growing regions of North-West Algeria. Morphological characterization under standard conditions and polymerase chain reaction (PCR) analyses using specific primers to amplify a part of the ITS regions and the 5.8S gene were conducted to confirm their identification as members of the alternata section. They were then examined according to morphological characteristics of conidia and sporulation patterns on potato carrot agar (PCA) and were segregated into three morphological species: A. alternata, A. tenuissima and A. arborescens. Colony type, substrate colour, margin, zonation, pigmentation, colony diameter and conidia production were studied on potato sucrose agar (PSA). Physiological parameters and nutritional requirements of the isolates were also assessed and a data matrix based on cluster analysis and Euclidean distance was constructed. Results of pathogenicity test on tomato showed obvious diversity among the isolates and they could be separated into two groups based on their virulence. The dendrogram based on the influence of cultural, nutritional and physiological characters suggests moderate heterogeneity within the populations of A. alternata and A. tenuissima. The small-spore species formed five clusters that fundamentally paralleled the morphological groupings. However, the results provided no evidence for geographical and pathogenicity clustering of isolates

Conformal Current Algebra in Two Dimensions

We construct a non-chiral current algebra in two dimensions consistent with conformal invariance. We show that the conformal current algebra is realized in non-linear sigma-models on supergroup manifolds with vanishing dual Coxeter number, with or without a Wess-Zumino term. The current algebra is computed using two distinct methods. First we exploit special algebraic properties of supergroups to compute the exact two- and three-point functions of the currents and from them we infer the current algebra. The algebra is also calculated by using conformal perturbation theory about the Wess-Zumino-Witten point and resumming the perturbation series. We also prove that these models realize a non-chiral Kac-Moody algebra and construct an infinite set of commuting operators that is closed under the action of the Kac-Moody generators. The supergroup models that we consider include models with applications to statistical mechanics, condensed matter and string theory. In particular, our results may help to systematically solve and clarify the quantum integrability of PSU(n|n) models and their cosets, which appear prominently in string worldsheet models on anti-deSitter spaces.Comment: 33 pages, minor correction

Intermittent exploration on a scale-free network

We study an intermittent random walk on a random network of scale-free degree distribution. The walk is a combination of simple random walks of duration $t_w$ and random long-range jumps. While the time the walker needs to cover all the nodes increases with $t_w$, the corresponding time for the edges displays a non monotonic behavior with a minimum for some nontrivial value of $t_w$. This is a heterogeneity-induced effect that is not observed in homogeneous small-world networks. The optimal $t_w$ increases with the degree of assortativity in the network. Depending on the nature of degree correlations and the elapsed time the walker finds an over/under-estimate of the degree distribution exponent.Comment: 12 pages, 3 figures, 1 table, published versio

Alternaria species associated with early blight epidemics on tomato and other Solanaceae crops in northwestern Algeria

Early blight is a common disease of Solanaceae crops worldwide. The occurrence of Alternaria spp. was studied during three epidemics on tomato in northwestern Algeria. Alternaria was detected in more than 80 % of the diseased plant samples and accounted for more than 50 % of the total fungal isolates recovered from these samples. Morphological and molecular investigations revealed that small-spored isolates producing beaked conidia, i.e. belonging to the section alternaria, were prominent in most of the surveyed locations representing more than 80 % of the total Alternaria isolates in three locations (Mascara, Ain Témouchent and Sidi Belabbèsse). Based on their sporulation patterns they were recognized as A. alternata and A. tenuissima. Small-spored isolates producing conidia without beak and assigned to A. consortialis were also found at a low frequency (< 1 %). Large-spored isolates producing conidia ended by typical long beaks and identified as A. linariae (syn. A. tomatophila), A. solani and A. grandis were also recovered from all the sampled areas and represented 33.8 %, 6.3 % and 1.3 % of the total Alternaria isolates, respectively. Pathogenicity tests on tomato with a selection of 85 strains representative of the isolates collection revealed that all the tested isolates were able to produce extending lesions on inoculated leaves albeit with variable intensity. Large-spored species included the most aggressive isolates. Small-spored Alternaria, although less aggressive than large-spored Alternaria, had the ability to provoke brown necrotic spots and circumstantially developed synergistic interactions in mixed infections with moderately aggressive isolates of A. linariae

The conformal current algebra on supergroups with applications to the spectrum and integrability

We compute the algebra of left and right currents for a principal chiral model with arbitrary Wess-Zumino term on supergroups with zero Killing form. We define primary fields for the current algebra that match the affine primaries at the Wess-Zumino-Witten points. The Maurer-Cartan equation together with current conservation tightly constrain the current-current and current-primary operator product expansions. The Hilbert space of the theory is generated by acting with the currents on primary fields. We compute the conformal dimensions of a subset of these states in the large radius limit. The current algebra is shown to be consistent with the quantum integrability of these models to several orders in perturbation theory.Comment: 45 pages. Minor correction