On three dimensional bosonization

We discuss Abelian and non-Abelian three dimensional bosonization within the path-integral framework. We present a systematic approach leading to the construction of the bosonic action which, together with the bosonization recipe for fermion currents, describes the original fermion system in terms of vector bosons.Comment: 15 pages, LaTe

Root rot pathogens of Cinnamomum cassia in Vietnam

A study was conducted to determine the pathogens causing root rot, wilt and dieback disease of Cinnamomum cassia (Chinese cinnamon or cassia) in Vietnam, in nurseries and plantations in the Yen Bai, Quang Ninh, Thanh Hoa and Quang Nam provinces, and streams in the Yen Bai province. Pathogens were identified using morphology and internal transcribed spacer (ITS) sequence analysis. The 204 isolates obtained included 125 Phytophthora isolates and 79 from other oomycete genera. There were 112 isolates of P. cinnamomi, four P. heveae, two P. virginiana, three P. multibullata and four P. × vanyenensis. The pathogenicity and virulence of 16 P. cinnamomi, two P. heveae, two P. multibullata and four P. × vanyenensis isolates were assessed using lesion size after under-bark inoculation of C. cassia stems, and root damage following inoculation of 4-month-old C. cassia seedlings. The most virulent isolate from both assessments was a P. cinnamomi from the Quang Nam plantation. Isolates of P. cinnamomi showed a wide range of virulence, with isolates from healthy trees or seedlings showing the lowest virulence. Isolates of P. × vanyenensis, P. multibullata and P. heveae showed moderate or low pathogenicity. This study showed that although P. cinnamomi is the most common pathogen associated with dieback disease in Vietnamese C. cassia plantations, other Phytophthora species may also cause this disease. Knowledge of the presence of these soil- and waterborne pathogens will encourage improved soil and water hygiene in nurseries and implement measures to prevent the spread of the pathogens in plantations

The stability paradox : why expansion of education for women has not delayed age at first union or childbearing in Latin America

Despite substantial improvements in women's education, the age atwhich Latin American women marry (cohabit) or become mothers for the first time has barely decreased over the past four decades. We refer to this as the "stability paradox." We examine the relationship between years of schooling and transitions to first union or child, analyzing retrospective information from 50 cohorts of women born between 1940 and 1989 in 12 Latin American countries. Absolute and relative measures of schooling are compared. Data is drawn from 38 Demographic Health Surveys (DHS) conducted between 1986 and 2012 in these countries. Results show that expected postponement in family transitions due to educational expansion was offset by a rise in union formation and childbearing within strata of absolute education, but stayed approximately constant within strata of relative education. The relative measure of education retains the stratifying power of education but neutralizes any effect attached to a specific number of years of schooling and the learning skills associated with them. This is consistent with the idea that access to education in Latin America reproduces existing patterns of socioeconomic advantage, rather than creating a more equitable distribution of learning opportunities and outcomes

Comment on "Bicritical and Tetracritical Phenomena and Scaling Properties of the SO(5) Theory"

The multicritical point at which both a 3-component and a 2-component order parameters order simultaneously in 3 dimensions is shown to have the critical behavior of the decoupled fixed point, with separate n=3 and n=2 behavior. This contradicts both the extrapolation of the epsilon-expansion at leading order, which yields the biconical point, and recent Monte Carlo simulations, which gave isotropic SO(5) behavior. Thus, this tetracritical point carries no information on the relevance of the so-called SO(5) theory of high-T superconductivity.Comment: 1 pag

Three dimensional fermionic determinants, Chern-Simons and nonlinear field redefinitions

The three dimensional abelian fermionic determinant of a two component massive spinor in flat euclidean space-time is resetted to a pure Chern-Simons action through a nonlinear redefinition of the gauge field.Comment: 18 pages, latex2

Zero modes of six-dimensional Abelian vortices

We analyze the fluctuations of Nielsen-Olesen vortices arising in the six-dimensional Abelian-Higgs model. The regular geometry generated by the defect breaks spontaneously six-dimensional Poincar\'e symmetry leading to a warped space-time with finite four-dimensional Planck mass. As a consequence, the zero mode of the spin two fluctuations of the geometry is always localized but the graviphoton fields, corresponding to spin one metric fluctuations, give rise to zero modes which are not localized either because of their behaviour at infinity or because of their behaviour near the core of the vortex. A similar situation occurs for spin zero fluctuations. Gauge field fluctuations exhibit a localized zero mode.Comment: 45 pages in Revtex style with 4 figure

Topological and Universal Aspects of Bosonized Interacting Fermionic Systems in (2+1)d

General results on the structure of the bosonization of fermionic systems in $(2+1)$d are obtained. In particular, the universal character of the bosonized topological current is established and applied to generic fermionic current interactions. The final form of the bosonized action is shown to be given by the sum of two terms. The first one corresponds to the bosonization of the free fermionic action and turns out to be cast in the form of a pure Chern-Simons term, up to a suitable nonlinear field redefinition. We show that the second term, following from the bosonization of the interactions, can be obtained by simply replacing the fermionic current by the corresponding bosonized expression.Comment: 29 pages, RevTe

Nonlinear rheological characteristics of single species bacterial biofilms

Bacterial biofilms in natural and artificial environments perform a wide array of beneficial or detrimental functions and exhibit resistance to physical as well as chemical perturbations. In dynamic environments, where periodic or aperiodic flows over surfaces are involved, biofilms can be subjected to large shear forces. The ability to withstand these forces, which is often attributed to the resilience of the extracellular matrix. This attribute of the extracellular matrix is referred to as viscoelasticity and is a result of self-assembly and cross-linking of multiple polymeric components that are secreted by the microbes. We aim to understand the viscoelastic characteristic of biofilms subjected to large shear forces by performing Large Amplitude Oscillatory Shear (LAOS) experiments on four species of bacterial biofilms: Bacillus subtilis, Comamonas denitrificans, Pseudomonas fluorescens and Pseudomonas aeruginosa. We find that nonlinear viscoelastic measures such as intracycle strain stiffening and intracycle shear thickening for each of the tested species, exhibit subtle or distinct differences in the plot of strain amplitude versus frequency (Pipkin diagram). The biofilms also exhibit variability in the onset of nonlinear behaviour and energy dissipation characteristics, which could be a result of heterogeneity of the extracellular matrix constituents of the different biofilms. The results provide insight into the nonlinear rheological behaviour of biofilms as they are subjected to large strains or strain rates; a situation that is commonly encountered in nature, but rarely investigated

NGO Visit to Vietnam, 14-21 May 1991: Observations and Comments

A team of six representatives from non-governmental organizations (NGOs) in the United States, Canada and Australia visited Vietnam from 14 to 21 May 1991, to assess the situation of people who have returned under the voluntary repatriation program established by the Comprehensive Plan of Action (CPA) for Indochinese refugees