Robust Estimation of GARMA Model Parameters with an Application to Cointegration among Interest Rates of Industrialized Countries

We review the literature on long memory ARFIMA and GARMA models andintroduce a new efficient estimator for GARMA models, which we show to berobust. Next we conduct a Monte Carlo study to demonstate the power of theDickie–Fuller test when the data are generated from a stationary GARMAprocess. We conclude with a brief discussion of cointegration in the contextof GARMA models with an application to international interest rates.     

Between the wars

Abstract

During the 1930s the Julien Levy Gallery was the liveliest photographic centre in New York City. It opened in 1931, and it was Levy's plan to show photographs along with paintings and drawings and other works of art. It was at his Madison Avenue gallery that New Yorkers first saw the photographs of Atget that Berenice Abbott acquired shortly after the photographer's death, together with Julien Levy, who advanced the purchase funds. It was also there that Walker Evans had his first one-man show, and where Henri Cartier-Bresson was introduced to the American public. Through his series of exhibitions the New York public came to know the work of the avant garde in photography. Indeed, without Julien's pioneering work, the exhibition which the present reviewer organized for The Museum of Modern Art in 1937 would have been the poorer. Julien Levy has never received the recognition he deserves. Now, upon the occasion of receiving the Julien Levy Collection, partly as a gift, partly on extended loan, the Art Institute of Chicago has remedied the situation by publishing this modest but well illustrated and meticulously documented catalogue. Produced by David Travis, the museum's Associate Curator of Photography, it is, without question, the most important scholarly publication on the history of art photography between World Wars I and II. Not only does the book recreate the excitement of the discovery by Julien and his friends that photography was indeed a part of 'modern art', but it contains a wealth of information. Moreover, of the 58 photographs that are reproduced, three-quarters have not been previously published. They were made by 32 photographers. It is well to name them, for 15 have been almost entirely forgotten today. They were: Berenice Abbott, Manuel Alvarez-Bravo, Eugene Atget, Use Bing, Brassai:, Anton Bruehl, Henri Cartier-Bresson, Alvin Langdon Coburn, Imogen Cunningham, Walker Evans, Walter Hege, Gertrude Kasebier, Andre Kertesz, Clarence John Laughlin, Alice Lex-Nerlinger, Eli Lotar, George platt Lynes, Lee Miller, Lucia Moholy-Nagy, Laszlo Moholy-Nagy, Nadar, Oscar Nerlinger, Paul Outerbridge Jr, Roger Parry, Man Ray, Sherril V. Schell, Charles Sheeler, Emmanuel Sougez, Ralph Steiner, Paul Strand, Maurice Tabard, Umbo (Otto Umbehr), and Clarence H. White.     

Fitness Considerations for Contemporary Composite Materials: (Who’s Afraid of the Composite Micro-Crack?)

Avoiding the catastrophic failure of a large structure demands the material’s microstructure be designed in such as a way as to render any crack present innocuous thereby raising the integrity of that structure. Structural integrity of a composite material embraces contributions from: materials science and engineering; processing science; design and fabrication technology. It combines a number of interacting factors: the criticality of the application; the accessibility for and ability to inspect vital parts and components; the intended use including load spectrum and time; the consequences of impact, fatigue, temperature and hostile environment; the nature of inherent flaws; the constituent properties of the material system utilized; and it takes into account human factors.     

Partitioning a Square into Rectangles: NP-Completeness and Approximation Algorithms

In this paper we deal with two geometric problems arising from heterogeneous parallel computing: how to partition the unit square into p rectangles of given area s ₁ , s ₂ , . . . ,s _p (such that Σ _i=1 ^p s _i = 1 ), so as to minimize either (i) the sum of the p perimeters of the rectangles or (ii) the largest perimeter of the p rectangles? For both problems, we prove NP-completeness and we introduce a 7/4 -approximation algorithm for (i) and a $(2/\sqrt{3})$ -approximation algorithm for (ii).     

Overexpression of the ferritin H subunit in cultured erythroid cells changes the intracellular iron distribution

To test the hypothesis that variations in H- and L-subunit composition in the ferritin shell affect intracellular iron metabolism, we established stable transfectants of mouse erythroleukemia cells overexpressing the H-ferritin subunit. Analyses were performed on individual clones of transfected cells induced to differentiate with hexamethylenbisacetamide (HMBA). The results showed that there was a reduction in the amount of hemoglobin produced, in inverse relationship with the level of H-subunit overexpression. Incorporation of [2-14C]glycine into heme was reduced by 20% t0 30% in the clones overexpressing H-ferritin subunit compared with control clone. However, the reduction in hemoglobin production was not reversed by addition of heme precursors (delta-aminolevulinic acid or iron) or by hemin itself. A reduced accumulation of beta-globin mRNA was also observed, which could account for the impaired hemoglobin synthesis. Furthermore, synthesis of the endogenous L-ferritin subunit was greatly repressed. Gel retardation assays performed on cytoplasmic extracts of transfected cells using an iron-responsive element (IRE) as a probe revealed that in overexpressing cells, the iron-regulatory protein (IRP) had a conformation with a high RNA-binding affinity, thus leading to translational repression of the endogenous L-ferritin synthesis. These data suggest that an increased formation of H-rich isoferritins leads to a rapid chelation of the regulatory iron pool. While the mechanism underlying the reduction in beta-globin mRNA remains to be elucidated, this study provides direct evidence for the role of IRP-mediated regulation of ferritin expression in erythroid cell metabolism.