Chiral bosonization for non-commutative fields

A model of chiral bosons on a non-commutative field space is constructed and new generalized bosonization (fermionization) rules for these fields are given. The conformal structure of the theory is characterized by a level of the Kac-Moody algebra equal to $(1+ \theta^2)$ where $\theta$ is the non-commutativity parameter and chiral bosons living in a non-commutative fields space are described by a rational conformal field theory with the central charge of the Virasoro algebra equal to 1. The non-commutative chiral bosons are shown to correspond to a free fermion moving with a speed equal to $c^{\prime} = c \sqrt{1+\theta^2}$ where $c$ is the speed of light. Lorentz invariance remains intact if $c$ is rescaled by $c \to c^{\prime}$. The dispersion relation for bosons and fermions, in this case, is given by $\omega = c^{\prime} | k|$.Comment: 16 pages, JHEP style, version published in JHE

Modular Groups, Visibility Diagram and Quantum Hall Effect

We consider the action of the modular group $\Gamma (2)$ on the set of positive rational fractions. From this, we derive a model for a classification of fractional (as well as integer) Hall states which can be visualized on two ``visibility" diagrams, the first one being associated with even denominator fractions whereas the second one is linked to odd denominator fractions. We use this model to predict, among some interesting physical quantities, the relative ratios of the width of the different transversal resistivity plateaus. A numerical simulation of the tranversal resistivity plot based on this last prediction fits well with the present experimental data.Comment: 17 pages, plain TeX, 4 eps figures included (macro epsf.tex), 1 figure available from reques

Role of right posterior parietal cortex in maintaining attention to spatial locations over time

Recent models of human posterior parietal cortex (PPC) have variously emphasized its role in spatial perception, visuomotor control or directing attention. However, neuroimaging and lesion studies also suggest that the right PPC might play a special role in maintaining an alert state. Previously, assessments of right-hemisphere patients with hemispatial neglect have revealed significant overall deficits on vigilance tasks, but to date there has been no demonstration of a deterioration of performance over time--a vigilance decrement--considered by some to be a key index of a deficit in maintaining attention. Moreover, sustained attention deficits in neglect have not specifically been related to PPC lesions, and it remains unclear whether they interact with spatial impairments in this syndrome. Here we examined the ability of right-hemisphere patients with neglect to maintain attention, comparing them to stroke controls and healthy individuals. We found evidence of an overall deficit in sustaining attention associated with PPC lesions, even for a simple detection task with stimuli presented centrally. In a second experiment, we demonstrated a vigilance decrement in neglect patients specifically only when they were required to maintain attention to spatial locations, but not verbal material. Lesioned voxels in the right PPC spanning a region between the intraparietal sulcus and inferior parietal lobe were significantly associated with this deficit. Finally, we compared performance on a task that required attention to be maintained either to visual patterns or spatial locations, matched for task difficulty. Again, we found a vigilance decrement but only when attention had to be maintained on spatial information. We conclude that sustaining attention to spatial locations is a critical function of the human right PPC which needs to be incorporated into models of normal parietal function as well as those of the clinical syndrome of hemispatial neglect

Electronic cigarettes: A position statement from the Thoracic Society of Australia and New Zealand*

The TSANZ develops position statements where insufficient data exist to write formal clinical guidelines. In 2018, the TSANZ addressed the question of potential benefits and health impacts of electronic cigarettes (EC). The working party included groups focused on health impacts, smoking cessation, youth issues and priority populations. The 2018 report on the Public Health Consequences of E-Cigarettes from the United States NASEM was accepted as reflective of evidence to mid-2017. A search for papers subsequently published in peer-reviewed journals was conducted in August 2018. A small number of robust and important papers published until March 2019 were also identified and included. Groups identified studies that extended, modified or contradicted the NASEM report. A total of 3793 papers were identified and reviewed, with summaries and draft position statements developed and presented to TSANZ membership in April 2019. After feedback from members and external reviewers, a collection of position statements was finalized in December 2019. EC have adverse lung effects and harmful effects of long-term use are unknown. EC are unsuitable consumer products for recreational use, part-substitution for smoking or long-term exclusive use by former smokers. Smokers who require support to quit smoking should be directed towards approved medication in conjunction with behavioural support as having the strongest evidence for efficacy and safety. No specific EC product can be recommended as effective and safe for smoking cessation. Smoking cessation claims in relation to EC should be assessed by established regulators