We give a proof of the Nirenberg-Treves conjecture: that local solvability of principal type pseudo-differential operators is equivalent to condition (Psi). This condition rules out sign changes from - to + of the imaginary part of the principal symbol along the oriented bicharacteristics of the real part. We obtain local solvability by proving a localizable a priori estimate for the adjoint opera

Bakgrund till samt redogörelse för inrättandet av Lunds universitets årsskrift 1864 som ett forum för vetenskaplig publicering.

We consider the problem of computing the product of two n×n Boolean matrices A and B. For an n×n Boolean matrix C, let GC be the complete weighted graph on the rows of C where the weight of an edge between two rows is equal to its Hamming distance, i.e., the number of entries in the first row having values different from the corresponding entries in the second one. Next, letMWT(C) be the weight of a

Traditional efforts in standardizing video coding used to involve a lengthy process that resulted in large monolithic standards and reference codes. This approach has become increasingly ill-suited to the dynamics and the fast changing needs of the video coding community. Most importantly, there used to be no principled approach to leveraging the significant commonalities between the different cod

Popular Abstract in Swedish Bekämpningsmedel och algblomningar - finns det någon koppling? Inom det konventionella jordbruket används idag regelmässigt stora mängder bekämpnings-medel, bara i sverige spreds under år 2001 mer än 1700 ton kemiska bekämpnings-medel på åkrarna. Ett stort problem med användandet av dessa ämnen är risken att de sprids och förorenar den intilliggande naturen. De kan driIn this thesis I have investigated the effects of pesticide exposure on the ecosystem level using various types of experimental ecosystems, i.e. microcosms. The direct effect of exposure to cyperemthrin, a pyretroid insecticide, was a rapid decrease of crustancean zooplankton in enclosures in a lake. In the exposed enclosures the biomass of algae, heterotrophic nanoflagellates, ciliates and bacter

Complex and widespread activation in many brain areas is seen while performing, listening or mentally imaging music, activity that varies with training, previous exposure, personal preference, emotional involvement and many other factors. Playing a musical instrument demands extensive motor and cognitive abilities, and early musical learning results in plastic reorganization of the developing brai

The present thesis analyzes the reform of congregational singing in Livonia and Estonia in the first half of the 19th century. In this process the writings on the aesthetics of the congregational singing of a German pastor Johann Leberecht Ehregott Punschel (1778–1849) active in Livonia, and a chorale book (1839) that he edited occupied the central place. Punschel’s activities are directly associa

The growing social polarisation in Swedish society has increased the differences between pour and rich districts in the larger cities. The situation is worst in the housing areas built in the 1960s. But although Swedish urban policy has aimed for several decades at controlling segregation through extraordinary efforts in vulnerable housing areas, there is nothing to indicate that the processes of