32622 Imaging technologies for presurgical margin assessment of basal cell carcinoma

Basal cell carcinoma (BCC) is the most common skin cancer worldwide. Mohs micrographic surgery is a highly used BCC treatment, involving staged resection of the tumor with complete histologic evaluation of the peripheral margins. A reduction in the number of Mohs stages would significantly improve care and could result in substantial economic benefits, estimated at $36 million USD in savings per annum. Noninvasive imaging modalities can potentially streamline the surgical management of skin cancers by refining presurgical assessments of tumor size. We assessed the current imaging techniques in dermatology and their application for tumor margin assessment of BCCs prior to Mohs micrographic surgery. These include dermoscopy, photodynamic diagnosis (PDD), high-frequency ultrasound (HFUS), optical coherence tomography (OCT), reflectance confocal microscopy (RCM), and optical polarization imaging (OPI). Each technology is limited or strengthened by its resolution, depth, speed of imaging, field of view, maneuverability, and billing. RCM, and a combination of RCM with video mosaicking technique and OCT, appear to be promising imaging techniques in pre-surgical margin assessment because of the superior resolution of RCM and the enhanced depth of imaging of OCT. OPI is also favorable for margin assessment based on its field of view and maneuverability. Further research and efficacy studies are necessary before such techniques can be implemented widely. It is imperative that general dermatologists and Mohs surgeons alike are well informed regarding the existing technologies given the increasing incidence of skin cancer and the associated rising costs

1861-09-17 L.T. Boothby inquires about Simon McCausland\u27s return to his regiment

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1861-11-27 Mr. Boothby recommends Winfield Scott Howe for a commission

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Depth of maximum of extensive air showers and cosmic ray composition above 10**17 eV in the geometrical multichain model of nuclei interactions

The depth of maximum for extensive air showers measured by Fly's Eye and Yakutsk experiments is analysed. The analysis depends on the hadronic interaction model that determine cascade development. The novel feature found in the cascading process for nucleus-nucleus collisions at high energies leads to a fast increase of the inelasticity in heavy nuclei interactions without changing the hadron-hadron interaction properties. This effects the development of the extensive air showers initiated by heavy primaries. The detailed calculations were performed using the recently developed geometrical multichain model and the CORSIKA simulation code. The agreement with data on average depth of shower maxima, the falling slope of the maxima distribution, and these distribution widths are found for the very heavy cosmic ray mass spectrum (slightly heavier than expected in the diffusion model at about 3*10**17 eV and similar to the Fly's Eye composition at this energy).Comment: 11pp (9 eps figures

On the invariant causal characterization of singularities in spherically symmetric spacetimes

The causal character of singularities is often studied in relation to the existence of naked singularities and the subsequent possible violation of the cosmic censorship conjecture. Generally one constructs a model in the framework of General Relativity described in some specific coordinates and finds an ad hoc procedure to analyze the character of the singularity. In this article we show that the causal character of the zero-areal-radius (R=0) singularity in spherically symmetric models is related with some specific invariants. In this way, if some assumptions are satisfied, one can ascertain the causal character of the singularity algorithmically through the computation of these invariants and, therefore, independently of the coordinates used in the model.Comment: A misprint corrected in Theor. 4.1 /Cor. 4.

Structural Analysis of Historical Constructions by Graphic Methodologies based on Funicular and Projective Geometry

This paper presents a graphic methodology for the structural analysis of domes and other surfaces of revolution, based on a combined use of funicular and projective geometry. By considering a dome as a network of lines of latitude and longitude, the equilibrium of the network is analyzed in both horizontal and vertical projection. The resulting dual configuration is also a spatial system that can be considered by its projection in a horizontal and a vertical plane. The dome is divided by latitude and longitude into an arbitrary number of sectors, and the equilibrium is enforced at each node. The tangential forces can be considered for their net effect at each node; the net effect of two tangential forces, equal in magnitude, at a node is a radially directed force in the plane of the line of latitude, acting outwards (compression) or inwards (tension). Considering their horizontal projection, and its dual form, it is possible to choose the shape of the radial force diagram (the vertical projection and the force diagram), and identify the radial forces associated with it, and thus the tangential forces. The new methodology is presented through its application to a hemispherical brick dome of small thickness. The hemispherical brick dome has been also analyzed by applying the slicing technique, considering different hypotheses regarding the structural behavior of the haunch filling, according to its morphological characterization. The structural analysis of the brick dome using both methodologies allows us to contrast the results obtained

On the cyclically fully commutative elements of Coxeter groups

Let W be an arbitrary Coxeter group. If two elements have expressions that are cyclic shifts of each other (as words), then they are conjugate (as group elements) in W. We say that w is cyclically fully commutative (CFC) if every cyclic shift of any reduced expression for w is fully commutative (i.e., avoids long braid relations). These generalize Coxeter elements in that their reduced expressions can be described combinatorially by acyclic directed graphs, and cyclically shifting corresponds to source-to-sink conversions. In this paper, we explore the combinatorics of the CFC elements and enumerate them in all Coxeter groups. Additionally, we characterize precisely which CFC elements have the property that powers of them remain fully commutative, via the presence of a simple combinatorial feature called a band. This allows us to give necessary and sufficient conditions for a CFC element w to be logarithmic, that is, ℓ(wk)=k⋅ℓ(w) for all k≥1, for a large class of Coxeter groups that includes all affine Weyl groups and simply laced Coxeter groups. Finally, we give a simple non-CFC element that fails to be logarithmic under these conditions

Twisted supersymmetric 5D Yang-Mills theory and contact geometry

We extend the localization calculation of the 3D Chern-Simons partition function over Seifert manifolds to an analogous calculation in five dimensions. We construct a twisted version of N=1 supersymmetric Yang-Mills theory defined on a circle bundle over a four dimensional symplectic manifold. The notion of contact geometry plays a crucial role in the construction and we suggest a generalization of the instanton equations to five dimensional contact manifolds. Our main result is a calculation of the full perturbative partition function on a five sphere for the twisted supersymmetric Yang-Mills theory with different Chern-Simons couplings. The final answer is given in terms of a matrix model. Our construction admits generalizations to higher dimensional contact manifolds. This work is inspired by the work of Baulieu-Losev-Nekrasov from the mid 90's, and in a way it is covariantization of their ideas for a contact manifold.Comment: 28 pages; v2: minor mistake corrected; v3: matches published versio

Geometric construction of D-branes in WZW models

The geometric description of D-branes in WZW models is pushed forward. Our starting point is a gluing condition\, $J_{+}=FJ_-$ that matches the model's chiral currents at the worldsheet boundary through a linear map $F$ acting on the WZW Lie algebra. The equivalence of boundary and gluing conditions of this type is studied in detail. The analysis involves a thorough discussion of Frobenius integrability, shows that $F$ must be an isometry, and applies to both metrically degenerate and nondegenerate D-branes. The isometry $F$ need not be a Lie algebra automorphism nor constantly defined over the brane. This approach, when applied to isometries of the form $F=R$ with $R$ a constant Lie algebra automorphism, validates metrically degenerate $R$-twined conjugacy classes as D-branes. It also shows that no D-branes exist in semisimple WZW models for constant\, $F=-R$.Comment: 23 pages, discussion of limitations of the gluing condition approach adde