Comparing Velscope VX and Traditional Oral Exams in Shisha (Hookah) Smokers: A Pilot Study

The purpose of this study was to compare oral findings using two exam types, the VELscope Vx® screening device versus a modified oral examination in detecting oral potentially malignant lesions in shisha smokers. Methods: Thirty-one participants who reported currently smoking shisha and tobacco were recruited. Participants were identified for smoking habits to include two groups, to include those who reported smoking shisha exclusively and those who reported smoking shisha and tobacco. Each group received both exam types; examiners used a standardized protocol. A health history questionnaire was also collected to assess participant\u27s oral cancer risk factors such as age, race, history of cancer, history of human papillomaviru.s, alcohol use, and length of time smoking. This demographic information was collected and compared across the two groups. Results: Of the 31 participants, 58% smoked shisha exclusively and 42 % smoked shisha and tobacco. Seventy-two percent of exclusive shisha smokers were male, 61 % were Asian, and the majority of study participants (89%) were between the ages of 19 and 34. No oral lesions were observed using VELscope Vx ® technology or modified oral examination. Conclusion: Due to the majority (89%) of the population being under 35 years of age, this population was not in an age group high risk for oral cancer. Exclusive shisha smokers were predominately Asian males. Alcohol was not found to be a significant risk factor for this study. Overall, a larger sample size is needed to determine the effectiveness of the VELscope compared to the traditional clinical oral cancer examination in shisha smokers

PT-Symmetric Quantum Electrodynamics and Unitarity

More than 15 years ago, a new approach to quantum mechanics was suggested, in which Hermiticity of the Hamiltonian was to be replaced by invariance under a discrete symmetry, the product of parity and time-reversal symmetry, $\mathcal{PT}$. It was shown that if $\mathcal{PT}$ is unbroken, energies were, in fact, positive, and unitarity was satisifed. Since quantum mechanics is quantum field theory in 1 dimension, time, it was natural to extend this idea to higher-dimensional field theory, and in fact an apparently viable version of $\mathcal{PT}$-invariant quantum electrodynamics was proposed. However, it has proved difficult to establish that the unitarity of the scattering matrix, for example, the K\"all\'en spectral representation for the photon propagator, can be maintained in this theory. This has led to questions of whether, in fact, even quantum mechanical systems are consistent with probability conservation when Green's functions are examined, since the latter have to possess physical requirements of analyticity. The status of $\mathcal{PT}$QED will be reviewed in this report, as well as the general issue of unitarity.Comment: 13 pages, 2 figures. Revised version includes new evidence for the violation of unitarit

Exact results for Casimir interactions between dielectric bodies: The weak-coupling or van der Waals Limit

In earlier papers we have applied multiple scattering techniques to calculate Casimir forces due to scalar fields between different bodies described by delta function potentials. When the coupling to the potentials became weak, closed-form results were obtained. We simplify this weak-coupling technique and apply it to the case of tenuous dielectric bodies, in which case the method involves the summation of van der Waals (Casimir-Polder) interactions. Once again exact results for finite bodies can be obtained. We present closed formulas describing the interaction between spheres and between cylinders, and between an infinite plate and a retangular slab of finite size. For such a slab, we consider the torque acting on it, and find non-trivial equilibrium points can occur.Comment: 4 pages, 3 figure

The Professoriate and the Post-Truth Era: A Historiographic Analysis of Expert Judgment and the Destabilization of Objective Truth

This paper explores the role that distrust of expert judgment plays in conservative critiques of higher education. We propose that academics should abandon the insistence on truth as the standard for the evaluation of research quality. Doing so would separate conservative critiques of higher education from broader concerns over expert judgment via the substitution of judgement criteria more readily accessible to laypeople. Based on evidence about how expert judgment actually functions, we propose utility as a standard accessible to all. We show this by describing a historiographic model of expert judgment within the research university. We close with a call for scholars to acknowledge the conflation of facts and values in their work—that is, its post-truth nature

Repulsive Casimir and Casimir-Polder Forces

Casimir and Casimir-Polder repulsion have been known for more than 50 years. The general "Lifshitz" configuration of parallel semi-infinite dielectric slabs permits repulsion if they are separated by a dielectric fluid that has a value of permittivity that is intermediate between those of the dielectric slabs. This was indirectly confirmed in the 1970s, and more directly by Capasso's group recently. It has also been known for many years that electrically and magnetically polarizable bodies can experience a repulsive quantum vacuum force. More amenable to practical application are situations where repulsion could be achieved between ordinary conducting and dielectric bodies in vacuum. The status of the field of Casimir repulsion with emphasis on recent developments will be surveyed. Here, stress will be placed on analytic developments, especially of Casimir-Polder (CP) interactions between anisotropically polarizable atoms, and CP interactions between anisotropic atoms and bodies that also exhibit anisotropy, either because of anisotropic constituents, or because of geometry. Repulsion occurs for wedge-shaped and cylindrical conductors, provided the geometry is sufficiently asymmetric, that is, either the wedge is sufficiently sharp or the atom is sufficiently far from the cylinder.Comment: 24 pages, 14 figures, contribution to the special issue of J. Phys. A honoring Stuart Dowker. This revision corrects typos and adds additional references and discussio