Interdependence and dynamics of essential services in an extensive risk context: a case study in Montserrat, West Indies

The essential services that support urban living are complex and interdependent, and their disruption in disasters directly affects society. Yet there are few empirical studies to inform our understanding of the vulnerabilities and resilience of complex infrastructure systems in disasters. This research takes a systems thinking approach to explore the dynamic behaviour of a network of essential services, in the presence and absence of volcanic ashfall hazards in Montserrat, West Indies. Adopting a case study methodology and qualitative methods to gather empirical data, we centre the study on the healthcare system and its interconnected network of essential services. We identify different types of relationship between sectors and develop a new interdependence classification system for analysis. Relationships are further categorised by hazard conditions, for use in extensive risk contexts. During heightened volcanic activity, relationships between systems transform in both number and type: connections increase across the network by 41%, and adapt to increase cooperation and information sharing. Interconnections add capacities to the network, increasing the resilience of prioritised sectors. This in-depth and context-specific approach provides a new methodology for studying the dynamics of infrastructure interdependence in an extensive risk context, and can be adapted for use in other hazard contexts

Deformation of a renormalization-group equation applied to infinite-order phase transitions

By adding a linear term to a renormalization-group equation in a system exhibiting infinite-order phase transitions, asymptotic behavior of running coupling constants is derived in an algebraic manner. A benefit of this method is presented explicitly using several examples.Comment: 6 pages, 5 figures, revtex4, typo corrected, references adde

Is the mean-field approximation so bad? A simple generalization yelding realistic critical indices for 3D Ising-class systems

Modification of the renormalization-group approach, invoking Stratonovich transformation at each step, is proposed to describe phase transitions in 3D Ising-class systems. The proposed method is closely related to the mean-field approximation. The low-order scheme works well for a wide thermal range, is consistent with a scaling hypothesis and predicts very reasonable values of critical indices.Comment: 4 page

Expression of soluble, active fragments of the morphogenetic protein SpoIIE from Bacillus subtilis using a library-based construct screen

SpoIIE is a dual function protein that plays important roles during sporulation in Bacillus subtilis. It binds to the tubulin-like protein FtsZ causing the cell division septum to relocate from mid-cell to the cell pole, and it dephosphorylates SpoIIAA phosphate leading to establishment of differential gene expression in the two compartments following the asymmetric septation. Its 872 residue polypeptide contains a multiple-membrane spanning sequence at the N-terminus and a PP2C phosphatase domain at the C-terminus. The central segment that binds to FtsZ is unlike domains of known structure or function, moreover the domain boundaries are poorly defined and this has hampered the expression of soluble fragments of SpoIIE at the levels required for structural studies. Here we have screened over 9000 genetic constructs of spoIIE using a random incremental truncation library approach, ESPRIT, to identify a number of soluble C-terminal fragments of SpoIIE that were aligned with the protein sequence to map putative domains and domain boundaries. The expression and purification of three fragments were optimised, yielding multimilligram quantities of the PP2C phosphatase domain, the putative FtsZ-binding domain and a larger fragment encompassing both these domains. All three fragments are monomeric and the PP2C domain-containing fragments have phosphatase activity

Efeito do fogo na fenologia de Syagrus glaucescens Glaz. ex Becc. (Arecaceae)

Abstract Syagrus glaucescens is an endemic and threatened palm from the rupestrian field of the Espinhaço Range, Minas Gerais, southeastern Brazil. The objective of this study was to evaluate the fire effect on the vegetative and reproductive phenology of S. glaucescens. It was tested the hypothesis that the occurrence of fire can affect the phenological patterns exhibited by this species. The study began after six months of fire occurrence. A total of 40 individuals were marked and observed monthly, 20 in a burned area (Queimado group) and 20 in an unburned adjacent area (Controle group), located in rupestrian fields areas of Serra do Cipó (MG). The analysis of phenophases was performed using the index of activity and the Fournier’s percent index of intensity. Leaf flushing and leaf fall were synchronous among the individuals of the two populations, during the studied period. The production of flowers and fruits on S. glaucescens was asynchronous for the most part of the time. However, in both studied areas most individuals were blooming during the dry season and fruiting in the rainy season. Rainfall seems to be the main factor determining the observed phenological patterns, and was significantly correlated with some phenophases of both burned and control groups. The burned plants flowered and fruited before the control group, and also produced a higher number of flowers and fruits, suggesting that fire may affect the phenology of this palm. Key words: endemic species, fire, rupestrian field, Serra do Cipó.Syagrus glaucescens é uma palmeira de pequeno porte, ameaçada de extinção e endêmica dos campos rupestres da Cadeia do Espinhaço, em Minas Gerais. O presente estudo teve como objetivo avaliar o efeito do fogo na fenologia vegetativa e reprodutiva de S. glaucescens. Foi testada a hipótese de que a ocorrência do fogo altera os ritmos fenológicos exibidos por esta espécie. O estudo teve início seis meses após a ocorrência do fogo. Foram marcados e observados, mensalmente, 20 indivíduos na área queimada (grupo Queimado) e 20 em uma área de controle adjacente (grupo Controle), localizados em áreas de campo rupestre da Serra do Cipó (MG). A análise das fenofases foi feita pelos métodos de índice de atividade e percentual de intensidade de Fournier. O brotamento e a senescência foliar foram constantes e sincrônicos entre os indivíduos das populações em praticamente todo o período estudado. A produção de flores e frutos em S. glaucescens foi assincrônica na maior parte do tempo. Entretanto, de uma forma geral, nos dois grupos avaliados, pôde-se observar maior percentual de indivíduos florescendo na estação seca e frutificando na estação chuvosa. A precipitação parece ser o principal fator determinante na definição dos padrões fenológicos, pois obteve correlação significativa com várias fenofases em ambos os grupos, Controle e Queimado. O grupo Queimado floresceu e frutificou antes do grupo Controle, além de ter produzido maior número de flores e frutos, sugerindo que o fogo afeta a fenologia desta palmeira. Palavras-chave: Campo rupestre, espécie endêmica, fogo, Serra do Cipó

Very long optical path-length from a compact multi-pass cell

The multiple-pass optical cell is an important tool for laser absorption spectroscopy and its many applications. For most practical applications, such as trace-gas detection, a compact and robust design is essential. Here we report an investigation into a multi-pass cell design based on a pair of cylindrical mirrors, with a particular focus on achieving very long optical paths. We demonstrate a path-length of 50.31 m in a cell with 40 mm diameter mirrors spaced 88.9 mm apart - a 3-fold increase over the previously reported longest path-length obtained with this type of cell configuration. We characterize the mechanical stability of the cell and describe the practical conditions necessary to achieve very long path-lengths

Finite size scaling in the 2D XY-model and generalized universality

In recent works (BHP), a generalized universality has been proposed, linking phenomena as dissimilar as 2D magnetism and turbulence. To test these ideas, we performed a MC study of the 2D XY-model. We found that the shape of the probability distribution function for the magnetization M is non Gaussian and independent of the system size --in the range of the lattice sizes studied-- below the Kosterlitz-Thoules temperature. However, the shape of these distributions does depend on the temperature, contrarily to the BHP's claim. This behavior is successfully explained by using an extended finite-size scaling analysis and the existence of bounds for M.Comment: 7 pages, 5 figures. Submitted to Phys. Rev. Lett. Details of changes: 1. We emphasized in the abstract the range of validity of our results. 2. In the last paragraph the temperature dependence of the PDF was slightly re-formulate

New version of the fluctuation Hamiltonian for liquids near the critical point

We propose new canonical form of the fluctuational Hamiltonian which takes into account the fact that in the vicinity of the critical point there are two fluctuating fields. They are the field of the number density and the entropy. The proposed canonical form is based on the $D_5$ catastrophe. In contrast to the standard approach of Landau-Ginzburg Hamiltonian which is based on $A_3$ catastrophe the canonical form proposed for the fluctuational Hamiltonian naturally includes the asymmetric coupling between the fields.Comment: 15 page

Transverse lattice calculation of the pion light-cone wavefunctions

We calculate the light-cone wavefunctions of the pion by solving the meson boundstate problem in a coarse transverse lattice gauge theory using DLCQ. A large-N_c approximation is made and the light-cone Hamiltonian expanded in massive dynamical fields at fixed lattice spacing. In contrast to earlier calculations, we include contributions from states containing many gluonic link-fields between the quarks.The Hamiltonian is renormalised by a combination of covariance conditions on boundstates and fitting the physical masses M_rho and M_pi, decay constant f_pi, and the string tension sigma. Good covariance is obtained for the lightest 0^{-+} state, which we identify with the pion. Many observables can be deduced from its light-cone wavefunctions.After perturbative evolution,the quark valence structure function is found to be consistent with the experimental structure function deduced from Drell-Yan pi-nucleon data in the valence region x > 0.5. In addition, the pion distribution amplitude is consistent with the experimental distribution deduced from the pi gamma^* gamma transition form factor and diffractive dissociation. A new observable we calculate is the probability for quark helicity correlation. We find a 45% probability that the valence-quark helicities are aligned in the pion.Comment: 27 pages, 9 figure