Regular dissections of an infinite strip

AbstractIn the early 1970s, Bro. U. Alfred Brousseau asked for the number of regions formed in an infinite strip by the mn segments that join m equally spaced points on one edge to n equally spaced points on the other. Using projective duality, we express the number of points, segments, and regions formed by Brousseau's configuration in terms of the numbers Lk(m,n) of lines that meet an m × n lattice array in exactly k points

Biological and toxicological investigations of Chicago area navigation projects

unpublishednot peer reviewe

Human Health Implications of Omega-3 and Omega-6 Fatty Acids in Blubber of the Bowhead Whale (Balaena mysticetus)

Concerns exist regarding the health and nutrition of subsistence-based communities in Alaska. An apparent increase in diabetes, heart disease, obesity, and other disease conditions among Alaska Natives has accompanied their change from a traditional diet to a more “Western” diet. In northern Alaska, the meat, maktak (epidermis and blubber), and other products of bowhead whales provide important components of Native diets. This study assessed the fatty acid constituents of bowhead whale blubber to evaluate their possible health benefits. Working with hunters in Barrow, Alaska, we acquired samples for chemical analysis from five blubber depths at each of six body locations. We used gas chromatography-mass spectrometry of fatty-acid picolinyl esters to confirm the fatty-acid composition of samples. Analyses indicated that bowhead blubber contains relatively high levels of omega-3 fatty acids and that, on average, blubber samples from sites at the umbilical girth contain more omega-3 fatty acids than do samples from a girth 1 m caudal to the blowhole (roughly at the axillary girth). Omega-6 fatty acids were rare or undetectable in all samples. Omega-3 fatty acids have been suggested or shown to be important in the treatment or prevention of many diseases, including elevated blood pressure and cholesterol, heart disease, stroke, diabetes, arthritis, depression, and some cancers. Beyond the cultural benefits associated with subsistence hunting of bowhead whales, consumption of bowhead whale blubber provides some important health and nutritional benefits.Il existe des inquiétudes quant à la santé et à l’alimentation des collectivités basées sur la subsistance en Alaska. L’augmentation apparente du diabète, des maladies cardiaques, des cas d’obésité et d’autres maladies chez les Autochtones de l’Alaska va de pair avec leur passage d’un régime alimentaire traditionnel à un régime plus « occidental ». Dans le nord de l’Alaska, la viande, maktak (épiderme et petit lard), et d’autres produits de la baleine boréale représentent d’importantes composantes du régime alimentaire des Autochtones. Dans le cadre de cette étude, nous nous sommes penchés sur les composants en acides gras du petit lard de la baleine boréale et ce, afin de déterminer leurs bienfaits possibles sur la santé. De concert avec des chasseurs de Barrow, en Alaska, nous avons prélevé des échantillons de cinq épaisseurs de petit lard provenant de chacun de six endroits différents du corps afin d’en faire l’analyse chimique. Nous avons utilisé la chromatographie en phase gazeuse et la spectrométrie de masse d’esters picoliniques d’acides gras pour confirmer la composition en acides gras des échantillons. Les analyses laissaient supposer que le petit lard de la baleine boréale a une teneur relativement élevée en acides gras oméga-3 et, qu’en moyenne, les échantillons de petit lard provenant des endroits situés à la hauteur ombilicale renferment de plus grandes quantités d’acides gras oméga-3 que les échantillons provenant d’un endroit situé 1 m de la queue jusqu’à l’évent (environ à la hauteur axillaire). Dans tous les échantillons, les acides gras oméga-6 se faisaient rares, voire même indécelables. Certaines recherches portent à croire ou démontrent que les acides gras oméga-3 jouent un rôle important dans le traitement ou la prévention de nombreuses maladies, dont l’hypertension artérielle, le taux de cholestérol élevé, les maladies du coeur, les accidents cérébrovasculaires, le diabète, l’arthrite, la dépression et certains cancers. En plus des avantages culturels liés à la chasse de subsistance de la baleine boréale, la consommation du petit lard de la baleine boréale présente d’importants avantages du point de vue de la santé et de l’alimentation

Pennsylvania Folklife Vol. 43, No. 2

• The America\u27s Industrial Heritage Project: A Model for Cultural Tourism • The Harmonists are Waiting for You • The Quest for Authenticity in Tourism and Folklife Studies • Tourism and the Old Order Amish • The Log Cabin: Notes on its Structure and Dissemination • On the Making of Die Union Choral Harmonie (1833): Evidence from Henry C. Eyer\u27s Working Papers • In Memoriam: Paul R. Wieand, a True Artisthttps://digitalcommons.ursinus.edu/pafolklifemag/1139/thumbnail.jp

On the identity of Navicula gottlandica (Bacillariophyta), with the description of two new species Navicula eileencoxiana and Navicula bergstromiana from the Australo-Pacific region

During the past two decades, the subantarctic diatom flora has been the subject of several detailed taxonomic revisions, resulting in the description of a large number of new species. During a survey of the freshwater diatom flora of Macquarie Island (southern Pacific Ocean), an unknown Navicula species was observed showing resemblance to Navicula gottlandica. Populations of similar diatoms (previously reported as N. gottlandica) from Tasmania were also investigated. We here present a detailed morphological analysis of these diatoms, and compare it with the type material of N. gottlandica

Continuation for thin film hydrodynamics and related scalar problems

This chapter illustrates how to apply continuation techniques in the analysis of a particular class of nonlinear kinetic equations that describe the time evolution through transport equations for a single scalar field like a densities or interface profiles of various types. We first systematically introduce these equations as gradient dynamics combining mass-conserving and nonmass-conserving fluxes followed by a discussion of nonvariational amendmends and a brief introduction to their analysis by numerical continuation. The approach is first applied to a number of common examples of variational equations, namely, Allen-Cahn- and Cahn-Hilliard-type equations including certain thin-film equations for partially wetting liquids on homogeneous and heterogeneous substrates as well as Swift-Hohenberg and Phase-Field-Crystal equations. Second we consider nonvariational examples as the Kuramoto-Sivashinsky equation, convective Allen-Cahn and Cahn-Hilliard equations and thin-film equations describing stationary sliding drops and a transversal front instability in a dip-coating. Through the different examples we illustrate how to employ the numerical tools provided by the packages auto07p and pde2path to determine steady, stationary and time-periodic solutions in one and two dimensions and the resulting bifurcation diagrams. The incorporation of boundary conditions and integral side conditions is also discussed as well as problem-specific implementation issues

The Astropy Problem

The Astropy Project (http://astropy.org) is, in its own words, "a community effort to develop a single core package for Astronomy in Python and foster interoperability between Python astronomy packages." For five years this project has been managed, written, and operated as a grassroots, self-organized, almost entirely volunteer effort while the software is used by the majority of the astronomical community. Despite this, the project has always been and remains to this day effectively unfunded. Further, contributors receive little or no formal recognition for creating and supporting what is now critical software. This paper explores the problem in detail, outlines possible solutions to correct this, and presents a few suggestions on how to address the sustainability of general purpose astronomical software

The representation of snow in land surface schemes: results from PILPS 2(d)

Permission to place copies of these works on this server has been provided by the American Meteorological Society (AMS). The AMS does not guarantee that the copies provided here are accurate copies of the published work. © Copyright 2001 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/AMS) or from the AMS at 617-227-2425 or [email protected] land surface schemes (LSSs) performed simulations forced by 18 yr of observed meteorological data from a grassland catchment at Valdai, Russia, as part of the Project for the Intercomparison of Land-Surface Parameterization Schemes (PILPS) Phase 2(d). In this paper the authors examine the simulation of snow. In comparison with observations, the models are able to capture the broad features of the snow regime on both an intra- and interannual basis. However, weaknesses in the simulations exist, and early season ablation events are a significant source of model scatter. Over the 18-yr simulation, systematic differences between the models’ snow simulations are evident and reveal specific aspects of snow model parameterization and design as being responsible. Vapor exchange at the snow surface varies widely among the models, ranging from a large net loss to a small net source for the snow season. Snow albedo, fractional snow cover, and their interplay have a large effect on energy available for ablation, with differences among models most evident at low snow depths. The incorporation of the snowpack within an LSS structure affects the method by which snow accesses, as well as utilizes, available energy for ablation. The sensitivity of some models to longwave radiation, the dominant winter radiative flux, is partly due to a stability-induced feedback and the differing abilities of models to exchange turbulent energy with the atmosphere. Results presented in this paper suggest where weaknesses in macroscale snow modeling lie and where both theoretical and observational work should be focused to address these weaknesses