Geometry of contours and Peierls estimates in d=1 Ising models

Following Fr\"ohlich and Spencer, we study one dimensional Ising spin systems with ferromagnetic, long range interactions which decay as $|x-y|^{-2+\alpha}$, $0\leq \alpha\leq 1/2$. We introduce a geometric description of the spin configurations in terms of triangles which play the role of contours and for which we establish Peierls bounds. This in particular yields a direct proof of the well known result by Dyson about phase transitions at low temperatures.Comment: 28 pages, 3 figure

"For terror of the deadness beyond": arctic environments and inhuman ecologies in Michelle Paver’s "Dark matter"

In this essay I examine Michelle Paver’s 2010 novel "Dark Matter", a ghost story, for how her use of \ud the gothic and horror contributes to undermining pastoral and romantic fantasies about the Arctic. \ud Drawing on the history of whale, walrus, and seal hunting in Svalbard, the site of the novel’s 1937 \ud scientific expedition, and my own experience there, I look at the tension Paver creates between the beauty \ud of the Svalbard environment and its long history as a location for human violence against nonhuman \ud animals. I suggest that, through the figure of the "gengånger", or “one who walks again,” and the built \ud environment and relics in Svalbard, Paver works to transmit both the violence of harvesting marine \ud mammals and the violence men perpetrate against each other in the name of resource extraction. In this \ud essay I engage in dialogue with recent environmental humanities work on ecophobia, dark ecologies, and \ud the ecocritical uses of fear, and argue for the consideration of the ghost story, a genre little studied by \ud ecocritics. Through highlighting the novel’s focus on violence linked to extractive practices, I suggest, \ud finally, that "Dark Matter" performs two important functions: it records past inhuman ecologies and it opens \ud out onto a reading of contemporary Arctic geopolitics.Este ensayo analiza cómo el uso de narrativas góticas y de terror en la novela de Michelle Paver \ud "Dark Matter" (La materia oscura, 2010), un cuento de fantasmas, debilita las fantasías bucólicas y \ud románticas del Ártico. Recurriendo a la historia de la caza de ballenas, morsas y focas en Svalbard, el \ud emplazamiento de la expedición científica de 1937 de la novela, así como mi propia experiencia allí, \ud analizo la tensión creada por Paver entre la belleza del medio ambiente de Svalbard y su larga historia \ud como lugar de violencia humana contra animales no-humano. Sugiero que, a través de la figura del \ud "gengänger", o “el que anda otra vez,” las reliquias y el medio ambiente construido de Svalbard, Paver \ud intenta transmitir tanto la violencia de la cosecha y comercio de mamíferos marinos como la que \ud perpetúan los hombres contra sí mismos en nombre de la extracción de recursos. En este ensayo entro en \ud dialogo con el trabajo reciente de las humanidades medioambientales sobre la ecofobia, las ecologías \ud oscuras, y el uso del miedo en la ecocrítica, y propongo el estudio del cuento de fantasmas, un género que \ud ha recibido poca atención de los ecocríticos. Al destacar el foco de la novela sobre la violencia relacionada \ud con las prácticas de extracción, sugiero, finalmente, que "Dark Matter", tiene dos funciones importantes: \ud graba ecologías inhumanas del pasado y abre una lectura de la geopolítica del Ártico contemporánea

An integrated LANDSAT/ancillary data classification of desert rangeland

Range inventorying methods using LANDSAT MSS data, coupled with ancillary data were examined. The study area encompassed nearly 20,000 acres in Rush Valley, Utah. The vegetation is predominately desert shrub and annual grasses, with some annual forbs. Three LANDSAT scenes were evaluated using a Kauth-Thomas brightness/greenness data transformation (May, June, and August dates). The data was classified using a four-band maximum-likelihood classifier. A print map was taken into the field to determine the relationship between print symbols and vegetation. It was determined that classification confusion could be greatly reduced by incorporating geomorphic units and soil texture (coarse vs fine) into the classification. Spectral data, geomorphic units, and soil texture were combined in a GIS format to produce a final vegetation map identifying 12 vegetation types

Detecting agricultural to urban land use change from multi-temporal MSS digital data

Conversion of agricultural land to a variety of urban uses is a major problem along the Wasatch Front, Utah. Although LANDSAT MSS data is a relatively coarse tool for discriminating categories of change in urban-size plots, its availability prompts a thorough test of its power to detect change. The procedures being applied to a test area in Salt Lake County, Utah, where the land conversion problem is acute are presented. The identity of land uses before and after conversion was determined and digital procedures for doing so were compared. Several algorithms were compared, utilizing both raw data and preprocessed data. Verification of results involved high quality color infrared photography and field observation. Two data sets were digitally registered, specific change categories internally identified in the software, results tabulated by computer, and change maps printed at 1:24,000 scale

Cyclic cycle systems of the complete multipartite graph

In this paper, we study the existence problem for cyclic $\ell$-cycle decompositions of the graph $K_m[n]$, the complete multipartite graph with $m$ parts of size $n$, and give necessary and sufficient conditions for their existence in the case that $2\ell \mid (m-1)n$

A Novel Hierarchy of Integrable Lattices

In the framework of the reduction technique for Poisson-Nijenhuis structures, we derive a new hierarchy of integrable lattice, whose continuum limit is the AKNS hierarchy. In contrast with other differential-difference versions of the AKNS system, our hierarchy is endowed with a canonical Poisson structure and, moreover, it admits a vector generalisation. We also solve the associated spectral problem and explicity contruct action-angle variables through the r-matrix approach.Comment: Latex fil

Integrable semi-discretization of the coupled nonlinear Schr\"{o}dinger equations

A system of semi-discrete coupled nonlinear Schr\"{o}dinger equations is studied. To show the complete integrability of the model with multiple components, we extend the discrete version of the inverse scattering method for the single-component discrete nonlinear Schr\"{o}dinger equation proposed by Ablowitz and Ladik. By means of the extension, the initial-value problem of the model is solved. Further, the integrals of motion and the soliton solutions are constructed within the framework of the extension of the inverse scattering method.Comment: 27 pages, LaTeX2e (IOP style

Deep learning-based parameter mapping for joint relaxation and diffusion tensor MR Fingerprinting

Magnetic Resonance Fingerprinting (MRF) enables the simultaneous quantification of multiple properties of biological tissues. It relies on a pseudo-random acquisition and the matching of acquired signal evolutions to a precomputed dictionary. However, the dictionary is not scalable to higher-parametric spaces, limiting MRF to the simultaneous mapping of only a small number of parameters (proton density, T1 and T2 in general). Inspired by diffusion-weighted SSFP imaging, we present a proof-of-concept of a novel MRF sequence with embedded diffusion-encoding gradients along all three axes to efficiently encode orientational diffusion and T1 and T2 relaxation. We take advantage of a convolutional neural network (CNN) to reconstruct multiple quantitative maps from this single, highly undersampled acquisition. We bypass expensive dictionary matching by learning the implicit physical relationships between the spatiotemporal MRF data and the T1, T2 and diffusion tensor parameters. The predicted parameter maps and the derived scalar diffusion metrics agree well with state-of-the-art reference protocols. Orientational diffusion information is captured as seen from the estimated primary diffusion directions. In addition to this, the joint acquisition and reconstruction framework proves capable of preserving tissue abnormalities in multiple sclerosis lesions