Tropical curves in sandpiles

We study a sandpile model on the set of the lattice points in a large lattice polygon. A small perturbation $\psi$ of the maximal stable state $\mu\equiv 3$ is obtained by adding extra grains at several points. It appears, that the result $\psi^\circ$ of the relaxation of $\psi$ coincides with $\mu$ almost everywhere; the set where $\psi^\circ\ne \mu$ is called the deviation locus. The scaling limit of the deviation locus turns out to be a distinguished tropical curve passing through the perturbation points. Nous consid\'erons le mod\`ele du tas de sable sur l'ensemble des points entiers d'un polygone entier. En ajoutant des grains de sable en certains points, on obtient une perturbation mineure de la configuration stable maximale $\mu\equiv 3$. Le r\'esultat $\psi^\circ$ de la relaxation est presque partout \'egal \`a $\mu$. On appelle lieu de d\'eviation l'ensemble des points o\`u $\psi^\circ\ne \mu$. La limite au sens de la distance de Hausdorff du lieu de d\'eviation est une courbe tropicale sp\'eciale, qui passe par les points de perturbation.Comment: small correction

The Impact of the Dutch Biopharmaceutical Industry on Regional Economic Development in the Randstad

The nature of economic development in advanced and developing economies alike has changed dramatically during the last generation as high-technology/knowledge-intensive industries have had a profound impact upon the way that people work and live. As The Economist has noted: "America gets more than half its economic growth from industries that barely existed a decade ago—such is the power of innovation, especially in the information and biotechnology industries.” The first phase of this revolution stemmed from the dramatic impact of information technologies such as the personal computer, software, the Internet, and now wireless communications. During the 1990s, an unprecedented stock market boom in the United States was driven by investment in these technologies. India, a country as poverty-stricken as any, has become an economic power because of its ability to effectively participate in the global information technology value chain. However, at present, the most important and the fastest growing segment of this emergent knowledge economy is biotechnology. While scientific knowledge as a whole has been doubling every ten years, it has been doubling every five years in the field of biology. The result has been a technological renaissance in biotechnology-related fields ranging from bioinformatics to biopharmaceuticals. This biotechnology-driven renaissance is reflected in the dramatic race to map the human genome and in the many new drugs that are influencing mankind's quality of life. The astounding rate of growth in this industry and a general desire to partake of its lucrative economic bounty has led national and regional governments to focus on the development of biotechnology clusters as a catalyst for regional economic development. Indeed, a survey of 77 local and 36 state economic development agencies in the U.S. reported that 83% have listed biotechnology as one of their top two targets for industrial development. For example, St. Louis, Missouri has sought to become a player in the field of agricultural biotechnology by creating a biotech cluster in the heart of its long-neglected inner-city. Outside the United States, Singapore has launched Biopolis, an 18.5 hectare, $300 million science park devoted exclusively to biomedical research and development; while neighboring Malaysia is doing the same with its BioValley Initiative. Thus, this keen focus on biotechnology is increasingly reshaping the physical environment of cities—both poor and rich—as they seek to become players in a lucrative industry of the future. Recently, continental Europe has also made a bid to become a dynamic player in the biotechnology industry as evidenced by the BioPartner Initiative of the Netherlands. How is this industry affecting the urban milieu? What is the impact of a particular high-technology industry—biotechnology--on regional economic development? Why have some areas been more successful than others in cultivating and developing biotechnology clusters? This paper will examine the evolution of the Dutch biopharmaceutical industry and its impact on regional economic development (real estate and labor markets) in the Randstad. Hypothesis: This dissertation is an examination of the consequences vis a vis regional economic development of biopharmaceutical clusters in the Randstad region of the Netherlands. These clusters are at different stages of evolution in respect to more advanced areas such as the United States and the UK; and are affected by a distinct policy environment. The clusters to be analyzed are situated in the polynuclear area of the Netherlands' Randstad. The historical dynamics of the biotechnology industry as well as the specific costs and benefits that it imposes upon the labor and real estate markets in this area will be assessed. The central hypotheses of this study is that the unique characteristics of the biotechnology industry is leading to gentrification (real estate impact); and that the biotechnology industry promotes bifurcation in the urban labor market as it enhances job growth amongst the highly skilled but is not a significant source of employment for the low and semi-skilled. The aforementioned gentrification hypothesis is built upon the anchor tenant hypothesis posited by Prof. Maryann Feldman in "The Locational Dynamics of the U.S. Biotech Industry: Knowledge Externalities and the Anchor Hypothesis.” Therein Dr. Feldman argues that an anchor tenant's brand recognition creates an externality for smaller stores who realize greater sales volume than they would in other locations. The value of this externality is reflected in higher rents the average tenant pays in comparison to the rent paid by the anchor tenant. This form of price discrimination reflects a willingness of the average tenants to pay a premium for location near the anchor tenant. Universities, hospitals and other components of the biotechnology cluster have the capacity to play the role of the anchor tenant, which is having a dramatic impact on the real estate and labor markets in the areas around biotech clusters

Sound Icon, Inaugural Concert: Acoustic Spaces, March 26, 2011

This is the concert program of the Sound Icon, Inaugural Concert: Acoustic Spaces performance on Saturday, March 26, 2011 at 8:00 p.m., at the Boston University Concert Hall, 855 Commonwealth Avenue, Boston, Massachusetts. Works performed were Fata Morgana by Davide Ianni, Receil de pierre de sable by Joshua Fineberg, and Les Espaces Acoustiques by Gérard Grisey. Digitization for Boston University Concert Programs was supported by the Boston University Center for the Humanities Library Endowed Fund

Les formes et dépôts nivéo-éoliens actuels en Antarctique et au Nouveau-Québec

En Antarctique, région de McMurdo, vallée de Victoria, des dépôts nivéo-éoliens, faits de lits alternants de neige et de sable entraînés par le vent, épais de 0 à 2 m, sont pérennes. Conjointement aux glaciers à sable inclus, ils sont peut-être apparentés aux dépôts stratifiés découverts par Mariner 9 dans la région polaire sud de la planète Mars.À Poste-de-la-Baleine, 55°17' Nord, 77°46' Ouest, les dépôts nivéo-éoliens sont annuels, toute la neige fondant chaque été. Ils contribuent à engraisser la première plage soulevée sableuse et certaines dunes. Sur le pied de glace, ils forment 1, 2 ou 3 remparts littoraux éphémères ; le plus haut est le plus proche du rivage. Sur la neige fraîche se forment des rides mixtes de sable et neige, dont le dessin ressemble à celui de champs de dunes vus d'avion (traverse, réticulé, lobé … etc.) et est beaucoup plus photogénique que celui des rides de neige sur neige ou de sable sur sable. Suivant la proportion relative de neige et de sable, l'albedo peut prendre toutes les valeurs entre celles de la neige pure et du sable pur : ainsi pourraient peut-être s'expliquer une partie des variations d'albedo, en fonction du temps, observées à la surface de Mars.Les formes de dénivation sont des cônes pointus, des mamelons doux dont la surface est craquelée typiquement, des boulettes de sable, des bourrelets de sable (micromoraines de dénivation) et des réseaux de sable. Sous les surplombs de la glace impure qui forme la base du nivéo-éolien sur l'estran, des gouttelettes tombent ; elles forment, si elles sont d'eau pure, des microcratères d'impact ; si elles sont de sable humide, des pastilles de sable ; dans les cas intermédiaires, des stalagmites de sable.In Antarctica, McMurdo region, Victoria Valley, niveo-eolian deposits, made of alternating layers of wind driven snow and sand, 0-2 m thick, are perennial. Together with sandy glaciers, they perhaps have some kinship with the layered deposits discovered by Mariner 9 in the south polar region of Mars.In Poste-de-la-Baleine, 55°17' N., 77°46' W., niveo-eolian deposits are annual with the snow melting down every year. They contribute to the nourishment of the first sandy raised beach and of some dunes. On the ice-foot, they form 1, 2 or 3 ephemeral beach-ridges, the highest (1-3 m) being nearest the shore. Mixed ripples of sand and snow form on the fresh snow ; this pattern is much like that of dune-fields as seen from the air (transverse, reticulate, lobate, etc.) and is much more photogenic than that of sand upon sand, or snow upon snow. According to the relative proportion of snow and sand, their albedo may have every value between that of pure snow and that of pure sand ; this might be one model, among others, of the variations with time observed in the albedo of the Martian surface. Denivation forms are sharp cones, soft rounded hillocks, the sandy surface of which is typically cracked, sand pellets, sand rolls (denivation micromoraines) and sand nets. Under overhanging impure ice, which forms the base of the niveo-eolian upon the shore-sand, falling droplets of melt-water, when pure, form impact microcraters ; if saturated with sand, flattened sand pellets ; if intermediate, sand stalagmites

Experimental and economic analysis of concrete absorber collector solar water heater with use of dimpled tube

To increase the usage of solar water heaters in India, a low-cost solar collector made of concrete is experimentally investigated in Pune. The concrete slab consisting metal fibers is placed in a wooden box, with immersed serpentine copper tube and provided with glazing on top. With an objective of improving the efficiency of the collector, a heat transfer augmentation technique (dimple) is fabricated on water carrying serpentine tube. Testing is carried out in rainy, winter and summer seasons for different water flow rates to understand the working of collector throughout the year. Testing results show that average water temperature collected per day is 59 °C-69 °C. Further, to find the exact effect of dimples on outlet water temperature, two completely identical concrete plate collectors-one with a dimpled tube and other with a smooth tube, are designed, fabricated and tested simultaneously. The effect of dimples is observed up to 2.5 °C. Also, a detailed economic analysis and environmental benefits of concrete collector solar water heater for India are investigated in this paper

Ground‐based measurements of NOx and total reactive oxidized nitrogen (NOy) at Sable Island, Nova Scotia, during the NARE 1993 summer intensive

Measurements of NO, NO2, and total reactive oxidized nitrogen (NOy) were added to ongoing measurements of aerosols, CO, and O3 at Sable Island (43°55′N, 60°01′W), Nova Scotia, during the North Atlantic Regional Experiment (NARE) 1993 summer intensive. Ambient levels of NOx and NOy were found to be highly variable, and elevated levels can be attributed to the transport of polluted continental air or presumably to relatively fresh emissions from sources upwind (e.g., ship traffic). The median values for NOx and NOy are 98 and 266 parts per trillion by volume (pptv), respectively. A multiday pollution episode occurred during which elevated NOx and NOy were observed with enhanced levels of O3, CO, and condensation nuclei. Air masses of recent tropical marine origin characterized by low and constant levels of O3 and CO were sampled after Hurricane Emily. The correlation between ozone and CO is reasonably good, although the relation is driven by the single pollution episode observed during the study. The correlation of O3 with NOy and with NOy‐NOx is complicated by the presumed NOy removal processes in the marine boundary layer. Examination of the radiosonde data and comparisons of the surface data with those obtained on the overflying aircraft provide clear indications of vertical stratification above the site

Presence of the “Threatened” \u3ci\u3eTrimerotropis Huroniana\u3c/i\u3e (Orthoptera: Acrididae) in Relation to the Occurrence of Native Dune Plant Species and the Exotic \u3ci\u3eCentaurea Biebersteinii\u3c/i\u3e

Trimerotropis huroniana Wlk. is a “Threatened” species in Michigan and Wisconsin with a distribution limited to open dune systems in the northern Great Lakes region of North America. Pitfall traps were utilized in the Grand Sable Dunes of Pictured Rocks National Lakeshore, MI, along with an herbaceous plant survey, to identify the relationship of T. huroniana with native dune plant species, Ammophila breviligulata Fern. (American beachgrass, Poaceae), Artemisia campestris L. (field sagewort, Asteraceae), and the exotic invasive plant Centaurea biebersteinii DC. [=Centaurea maculosa, spotted knapweed, Lamarck] (Asteraceae). The absence of C. biebersteinii resulted in an increased likelihood of capturing T. huroniana. This was most likely due to the increased likelihood of encountering A. campestris in areas without C. biebersteinii. The occurrence of A. breviligulata was independent of C. biebersteinii presence. A significant positive linear relationship occurred between the percent cover of A. campestris and the traps that captured T. huroniana. There was no significant relationship between A. breviligulata percent cover and the traps that captured T. huroniana. The occurrence and distribution of T. huroniana is closely related to the presence and abundance of A. campestris. Habitat conservation and improvement for T. huroniana should include increases in A. campestris populations through the removal of C. biebersteinii