Condensation of achiral simple currents in topological lattice models: a Hamiltonian study of topological symmetry breaking

We describe a family of phase transitions connecting phases of differing non-trivial topological order by explicitly constructing Hamiltonians of the Levin-Wen[PRB 71, 045110] type which can be tuned between two solvable points, each of which realizes a different topologically ordered phase. We show that the low-energy degrees of freedom near the phase transition can be mapped onto those of a Potts model, and we discuss the stability of the resulting phase diagram to small perturbations about the model. We further explain how the excitations in the condensed phase are formed from those in the original topological theory, some of which are split into multiple components by condensation, and we discuss the implications of our results for understanding the nature of general achiral topological phases in 2+1 dimensions in terms of doubled Chern-Simons theories

Legislative strengthening meets party support in international assistance: a closer relationship?

Recent reports recommend that international efforts to help strengthen legislatures in emerging democracies should work more closely with support for building stronger political parties and competitive party systems. This article locates the recommendations within international assistance more generally and reviews the arguments. It explores problems that must be addressed if the recommendations are to be implemented effectively. The article argues that an alternative, issue-based approach to strengthening legislatures and closer links with civil society could gain more traction. However, that is directed more centrally at promoting good governance for the purpose of furthering development than at democratisation goals sought by party aid and legislative strengtheners in the democracy assistance industry

Dehydration-induced tps gene transcripts from an anhydrobiotic nematode contain novel spliced leaders and encode atypical GT-20 family proteins

Accumulation of the non-reducing disaccharide trehalose is associated with desiccation tolerance during anhydrobiosis in a number of invertebrates, but there is little information on trehalose biosynthetic genes in these organisms.We have identified two trehalose-6-phosphate synthase (tps) genes in the anhydrobiotic nematode Aphelenchus avenae and determined full length cDNA sequences for both; for comparison, full length tps cDNAs from the model nematode, Caenorhabditis elegans, have also been obtained. The A. avenae genes encode very similar proteins containing the catalytic domain characteristic of the GT-20 family of glycosyltransferases and are most similar to tps-2 of C. elegans; no evidence was found for a gene in A. avenae corresponding to Ce-tps-1. Analysis of A. avenae tps cDNAs revealed several features of interest, including alternative trans-splicing of spliced leader sequences in Aav-tps-1, and four different, novel SL1-related transspliced leaders, which were different to the canonical SL1 sequence found in all other nematodes studied. The latter observation suggests that A. avenae does not comply with the strict evolutionary conservation of SL1 sequences observed in other species. Unusual features were also noted in predicted nematode TPS proteins, which distinguish them from homologues in other higher eukaryotes (plants and insects) and in micro-organisms. Phylogenetic analysis confirmed their membership of the GT-20 glycosyltransferase family, but indicated an accelerated rate of molecular evolution. Furthermore, nematode TPS proteins possess N- and C-terminal domains, which are unrelated to those of other eukaryotes: nematode C-terminal domains, for example, do not contain trehalose-6-phosphate phosphatase-like sequences, as seen in plant and insect homologues. During onset of anhydrobiosis, both tps genes in A. avenae are upregulated, but exposure to cold or increased osmolarity also results in gene induction, although to a lesser extent. Trehalose seems likely therefore to play a role in a number of stress responses in nematodes

Magnetic properties, domain-wall creep motion, and the Dzyaloshinskii-Moriya interaction in Pt/Co/Ir thin films

We study the magnetic properties of perpendicularly magnetized Pt/Co/Ir thin films and investigate the domain-wall creep method of determining the interfacial Dzyaloshinskii-Moriya (DM) interaction in ultrathin films. Measurements of the Co layer thickness dependence of saturation magnetization, perpendicular magnetic anisotropy, and symmetric and antisymmetric (i.e., DM) exchange energies in Pt/Co/Ir thin films have been made to determine the relationship between these properties. We discuss the measurement of the DM interaction by the expansion of a reverse domain in the domain-wall creep regime. We show how the creep parameters behave as a function of in-plane bias field and discuss the effects of domain-wall roughness on the measurement of the DM interaction by domain expansion. Whereas modifications to the creep law with DM field and in-plane bias fields have taken into account changes in the energy barrier scaling parameter α, we find that both α and the velocity scaling parameter v₀ change as a function of in-plane bias field

Socioeconomic indicators of health inequalities and female mortality: a nested cohort study within the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS)

Evidence is mounting that area-level socioeconomic indicators are important tools for predicting health outcomes. However, few studies have examined these alongside individual-level education. This nested cohort study within the control arm of the United Kingdom Collaborative Trial of Ovarian Cancer Screening (UKCTOCS) assesses the association of mutually adjusted individual (education) and area-level (Index of Multiple Deprivation-IMD 2007) socioeconomic status indicators and all-cause female mortality

The Normal State Resistivity of Grain Boundaries in YBa2Cu3O7-delta

Using an optimized bridge geometry we have been able to make accurate measurements of the properties of YBa2Cu3O7-delta grain boundaries above Tc. The results show a strong dependence of the change of resistance with temperature on grain boundary angle. Analysis of our results in the context of band-bending allows us to estimate the height of the potential barrier present at the grain boundary interface.Comment: 11 pages, 3 figure

The modular S-matrix as order parameter for topological phase transitions

We study topological phase transitions in discrete gauge theories in two spatial dimensions induced by the formation of a Bose condensate. We analyse a general class of euclidean lattice actions for these theories which contain one coupling constant for each conjugacy class of the gauge group. To probe the phase structure we use a complete set of open and closed anyonic string operators. The open strings allow one to determine the particle content of the condensate, whereas the closed strings enable us to determine the matrix elements of the modular $S$-matrix, also in the broken phase. From the measured broken $S$-matrix we may read off the sectors that split or get identified in the broken phase, as well as the sectors that are confined. In this sense the modular $S$-matrix can be employed as a matrix valued non-local order parameter from which the low-energy effective theories that occur in different regions of parameter space can be fully determined. To verify our predictions we studied a non-abelian anyon model based on the quaternion group $H=\bar{D_2}$ of order eight by Monte Carlo simulation. We probe part of the phase diagram for the pure gauge theory and find a variety of phases with magnetic condensates leading to various forms of (partial) confinement in complete agreement with the algebraic breaking analysis. Also the order of various transitions is established.Comment: 37 page

Adjusting to the COVID-19 Outbreak in the United States: The impact of disruptions on habits and changes in health behaviors

The COVID-19 pandemic provides a naturalistic test of whether pandemic-related disruptions weaken habits and undermine behavior stability. We hypothesized that better capacity to effortfully guide behavior (self-regulation) would buffer this effect and be associated with behavior stability and development of new habits to accomplish daily behaviors. A cross-sectional study of 416 MTurk workers recruited in April 2020 (Mage = 34.60, SD = 11.51) indicated that pandemic-related disruptions generally exceeded people’s capacity to effortfully modify their behavior. Self-regulation related to the development of new habits and to lower likelihood that work productivity decreased. Self-regulation also protected against the effect of disruption on the likelihood that substance use increased. Besides these associations, self-regulation was largely unrelated to health-related behaviors and, in some instances, associated with poorer outcomes. These findings underscore the need to appreciate the impact of contextual disruptions in interpreting and promoting change in health-related behaviors

How Adolescents Use Text Messaging Through their High School Years

Co‐construction theory suggests adolescents use digital communication to address developmental challenges. For a sample of 214 ethnically diverse adolescents, this research used direct observation to investigate the frequency, content, and timing of texting with parents, peers, and romantic partners through grades 9–12. Analyses showed that texting frequency follows a curvilinear trajectory, peaking in eleventh grade. Adolescents discussed a range of topics, predominantly with peers. Communication with parents was less frequent, but consistent over time. Approximately 45‐65% of adolescents communicated with romantic partners, texting heavily and about topics similar to those discussed with peers. Texting may help adolescents navigate key developmental challenges of adolescence—the establishment of autonomy, intimate peer relationships, romantic relationships, and self‐identity

A deuterium nuclear magnetic resonance study of chain disorder in lamellar potassium palmitate: The effect of long and short chain guests

The deuterium magnetic resonance spectra of lamellar phases of host perdeuterated potassium palmitate mixed with varying amounts of guest protiated potassium octanoate and behenate and 86.3 mol% D2O are reported. At higher temperatures, the short chain guests give rise to more fluidity and the long chain guests give rise to less fluidity towards the end of the host chain. At low temperatures there are changes in the interaction between the polar head group and the water which depend on sample composition. The transition from the lamellar phase to the low temperature gel phase is investigated and in some cases the gel phase is found to be a complicated many-phase region, at least for the water. The spectral results are presented in detail but compact and empirical methods of analysis are also investigated