A contribution to the closed geodesic problem

The closed geodesic problem has been solved by many authors under additional hypothesis. In this paper we develop a new way to solve this problem, by defining finitely many obstruction classes. This permits to enlarge significantly the family of manifolds for which this problem is solved. Our method which relies on the concept of A ∞ -section of a homomorphism of differential graded algebras, shows explicitly how the natural structure of shc-algebra on the singular cochains of a space comes into play

On the electron-scattering power of protein structures in the spinach chloroplast

The relative electron-scattering power of chromidia and interchromidia in protein structures of the spinach chloroplast was examined with the aid of the electron microscope. It has been demonstrated that: 1. 1. The technique of Marton and Schiff holds for WO3 crystals and silica films too. 2. 2. The mean electron-scattering constant of the chromidia amounts to about 1.34 times that of the interchromidia in preparations treated with acetone. After lipoid removal with lipase this value is 1.56. This indicates that the constitution of the chromidia is different from that of the interchromidia

Geochemical-geophysical investigations, Fairbanks district

Trace element distribution in a subarctic valley in the Cleary Hill area of the Fairbanks gold district has been studied. Zinc and arsenic have been found excellent pathfinder elements for auriferous deposits. Methods of analysis for copper, lead, zinc, molybdenum, silver and arsenic as well as heavy metals are discussed. The University of Alaska method #2 has been improved, Terrain, slope, and frozen ground have little effect upon the distribution of trace elements associated with the Cleary H i l l vein. A new method for the determination of zinc using dilute acid is proposed. Analysis of geochemical data by trend surface procedures proved effective for localization of anomalies

Thomas Slater to General Jacob Morris, October 3, 1828

Thomas Slater wrote from Lebanon, NY to Jacob Morris, addressed to Butternutts, Ostego County, NY to inform him of the death of Peter Kean, his son-in-law, the day before. Attached to this letter is another one dated May 25, 1931 it is addressed to Christine Griffin Kean Roosevelt, Peter\u27s granddaughter, from J.C. Pearson. Pearson had sent her the previous letter and offered to sell it to her for $2. People Included: Peter Philip James Kean, Sarah Sabina Kean, Mr. Dayton, Mr. Palmerhttps://digitalcommons.kean.edu/lhc_1820s/1011/thumbnail.jp

Seasonal Home Advantage in English Professional Football; 1974–2018

We study seasonal home advantage in English professional football over the period 1974 to 2018. We distinguish between absolute home advantage, enjoyed equally by all teams in a division, and relative home advantage, which differs among teams in the division. We find that absolute home advantage is substantial, ranging from 0.59 to 0.64 in terms of points per game or 0.44 to 0.46 in terms of goal difference. Likewise, clubs differ substantially in the relative home advantage they enjoy. Relative home advantage is positively related to within-team variation in attendance and the use of an artificial pitch. Despite big cross-divisional differences in attendance, absolute home advantage is about the same in all divisions. Finally, there is a substantial decline in absolute home advantage over time that materializes equally across divisions

Convective Vortices on Mars: A Reanalysis of Viking Lander 2 Meteorological Data, Sols 1-50

On 7th August 1976 the Viking 2 lander touched down at Utopia Planitia, Mars. We have reanalysed Viking lander 2 meteorological data, and it is the object of this research to give not only annual but diurnal statistics of convective vortex formation for the Viking 2 landing site

Using a Multi-Resolution Approach to Improve the Accuracy and Efficiency of Flooding Predictions

Main Objectives • Reduce the computational load by using a coarser resolution mesh when the storm track is uncertain • Increase the accuracy of predictions by using a higher resolution mesh as the storm approaches landfall • Increase the simulation possibilities including ensemble generation during operational forecastin

Drell-Yan production at small q_T, transverse parton distributions and the collinear anomaly

Using methods from effective field theory, an exact all-order expression for the Drell-Yan cross section at small transverse momentum is derived directly in q_T space, in which all large logarithms are resummed. The anomalous dimensions and matching coefficients necessary for resummation at NNLL order are given explicitly. The precise relation between our result and the Collins-Soper-Sterman formula is discussed, and as a by-product the previously unknown three-loop coefficient A^(3) is obtained. The naive factorization of the cross section at small transverse momentum is broken by a collinear anomaly, which prevents a process-independent definition of x_T-dependent parton distribution functions. A factorization theorem is derived for the product of two such functions, in which the dependence on the hard momentum transfer is separated out. The remainder factors into a product of two functions of longitudinal momentum variables and x_T^2, whose renormalization-group evolution is derived and solved in closed form. The matching of these functions at small x_T onto standard parton distributions is calculated at O(alpha_s), while their anomalous dimensions are known to three loops.Comment: 32 pages, 2 figures; version to appear in Eur. Phys. J.

Une histoire de cordes et de diagonales

Dans ces notes nous expliquons comment les applications diagonales relevées à l’espace des cordes permettent de définir toutes les opérations qui constituent la topologie des cordes. Les premières opérations ont été introduites par M. Chas etD. Sullivan, de manière élémentaire, en 1999. Depuis cette date la topologie des cordes a connu un développement rapide et ceci en interaction avec différents domaines des mathématiques qui seront évoqués dans le dernier chapitre. Bien que la définition de toutes les opérations soit un sujet ardu nous avons essayé d’en fournir une présentation la plus simple possible. Ceci est réalisable grâce à la notion d’application de Gysin d’une application continue, [17], qui met en évidence le caractère topologique de ces opérations et permet surtout une présentation commune du cas différentiable et du cas des espaces classifiants. La topologie des cordes peut être vue comme une partie de la Théorie Topologique des Cordes introduite par Witten dans l’étude de la théorie (physique) des cordes. (La théorie topologique des cordes est intimement reliée à différents domaines des mathématiques tels que, la théorie de Chern-Simons, les invariants de Gromov-Witten, la symétrie miroir,... ) Ce texte peut être lu « en diagonale » et sans aucun pré-requis en physique