A commutative higher cycle map into Deligne-Beilinson cohomology

Das Ziel dieser Arbeit ist die Konstruktion eines Homomorphismus von partiell definierten, graduiert-kommutativen Algebren, der nach Ubergang zu rationalen Kohomologiegruppen mit der Regulatorabbildung reg zwischen motivischer und Deligne-Beilinson Kohomologie übereinstimmt.rnZu Beginn der Arbeit werden verschiedene Komplexe beschrieben, mit denen sich die motivische und die Deligne-Beilinson Kohomologie berechnen lassen.rnIm ersten Kapitel wird der Komplex der höheren Chow Ketten und der Unterkomplex der "alternierenden" Ketten "in guter Lage" eingeführt, die beide die motivische Kohomologie berechnen (letzterer mit rationalen Koeffizienten).rnIn den folgenden beiden Kapiteln werden Komplexe C_D und P_D beschrieben, mit denen sich die (rationale) Deligne-Beilinson Kohomologie berechnen lässt. Diese sind aufgebaut aus sogenannten Strömen, die im zweiten Kapitel eingeführt werden. Verknüpft sind die beiden Komplexe durch eine Auswertungsabbildung ev, die für rationale Koeffizienten zu einem Quasi-Isomorphismus wird. Auf beiden Komplexen lassen sich (Schnitt-)Produkte definieren, von denen jedoch nur das Produkt auf P_D gleichzeitig assoziativ und graduiert-kommutativ ist.rnIm vierten Kapitel wird ganz allgemein für eine Familie von Komplexen, die einer Reihe an Anforderungen genügt, ein (partiell definierter) Homomorphismus (der Regulator) von dem Komplex der höheren Chow Ketten in eben diese Komplexe konstruiert. Die beiden oben genannten Komplexe erfüllen diese Anforderungen und liefern daher Regulatoren reg_C und reg_P

Mongodb tra i database non relazionali - focus su Map-Reduce e gestione della memoria

Panoramica delle caratteristiche dei database NoSQL, con dettaglio su MongoDB: filosofia di progettazione, modello dei dati, indicizzazione, algoritmo Map-Reduce e gestione della memoria.

Metodi di map-matching per l'identificazione degli itinerari dei ciclisti

Negli ultimi anni si è assistito al considerevole aumento della disponibilità di dati GPS e della loro precisione, dovuto alla diffusione e all’evoluzione tecnologica di smartphone e di applicazioni di localizzazione. Il processo di map-matching consiste nell’integrare tali dati - solitamente una lista ordinata di punti, identificati tramite coordinate geografiche ricavate mediante un sistema di localizzazione, come il GPS - con le reti disponibili; nell’ambito dell’ingegneria dei trasporti, l’obiettivo è di identificare il percorso realmente scelto dall’utente per lo spostamento. Il presente lavoro si propone l’obiettivo di studiare alcune metodologie di map-matching per l’identificazione degli itinerari degli utenti, in particolare della mobilità ciclabile. Nel primo capitolo è esposto il funzionamento dei sistemi di posizionamento e in particolare del sistema GPS: ne sono discusse le caratteristiche, la suddivisione nei vari segmenti, gli errori di misurazione e la cartografia di riferimento. Nel secondo capitolo sono presentati i vari aspetti del procedimento di map-matching, le sue principali applicazioni e alcune possibili classificazioni degli algoritmi di map-matching sviluppati in letteratura. Nel terzo capitolo è esposto lo studio eseguito su diversi algoritmi di map-matching, che sono stati testati su un database di spostamenti di ciclisti nell’area urbana di Bologna, registrati tramite i loro smartphone sotto forma di punti GPS, e sulla relativa rete. Si analizzano altresì i risultati ottenuti in un secondo ambiente di testing, predisposto nell’area urbana di Catania, dove sono state registrate in modo analogo alcune tracce di prova, e utilizzata la relativa rete. La comparazione degli algoritmi è eseguita graficamente e attraverso degli indicatori. Vengono inoltre proposti e valutati due algoritmi che forniscono un aggiornamento di quelli analizzati, al fine di migliorarne le prestazioni in termini di accuratezza dei risultati e di costo computazionale.

Three-dimensional electroanatomic entrainment map in atypical atrial flutter late after heart transplantation

Atrial flutter in the donor part of orthotopic heart transplants has been reported and successfully treated by radiofrequency ablation of the cavotricuspid isthmus, but mapping and ablation of atypical flutter circuits may be challenging.(1) Entrainment mapping has been used in combination with activation mapping to define the mechanism of atypical atrial flutter. Here, we report a case where colour-coded three-dimensional (3D) entrainment mapping allowed us to accurately determine and visualize the 3D location of the reentrant circuit and to plan the ablation of a left atrial flutter without the need for activation mapping.

The Politics of the "New North": Putting History and Geography at Stake in Arctic Futures

References to a “New North” have snowballed across popular media in the past 10 years. By invoking the phrase, scientists, policy analysts, journalists and others draw attention to the collision of global warming and global investment in the Arctic today and project a variety of futures for the region and the planet. While changes are apparent, the trope of a “New North” is not new. Discourses that appraised unfamiliar situations at the top of the world have recurred throughout the twentieth century. They have also accompanied attempts to cajole, conquer, civilize, consume, conserve and capitalize upon the far north. This article examines these politics of the “New North” by critically reading “New North” texts from the North American Arctic between 1910 and 2010. In each case, appeals to novelty drew from evaluations of the historical record and assessments of the Arctic’s shifting position in global affairs. “New North” authors pinpointed the ways science, state power, capital and technology transformed northern landscapes at different moments in time. They also licensed political and corporate influence in the region by delimiting the colonial legacies already apparent there. Given these tendencies, scholars need to approach the most recent iteration of the “New North” carefully without concealing or repeating the most troubling aspects of the Arctic’s past.

MAP kinase kinase 1 (MKK1) is essential for transmission of Trypanosoma brucei by Glossina morsitans

MAP kinase kinase 1 (MKK1) is encoded by a single copy gene in Trypanosoma brucei. It has been shown recently that MKK1 is not essential for bloodstream forms [14]. To investigate the requirement for MKK1 in other life-cycle stages we generated null mutants in procyclic forms of a fly-transmissible strain. These grew normally in culture and were able to establish midgut infections in tsetse at normal rates and intensities, but were incapable of colonising the salivary glands. Transformation of null mutants with an ectopic copy of MKK1 enabled parasites to complete the life cycle in tsetse and infect mice. This is the first example of a gene that is indispensable for transmission of T. brucei. It also raises the possibility that activating the MKK1 signalling cascade in vitro might trigger the differentiation and proliferation of life-cycle stages of T. brucei that are currently refractory to culture.

Metabolomics reveals the metabolic map of procainamide in humans and mice

Procainamide, a type I antiarrhythmic agent, is used to treat a variety of atrial and ventricular dysrhythmias. It was reported that long-term therapy with procainamide may cause lupus erythematosus in 25-30% of patients. Interestingly, procainamide does not induce lupus erythematosus in mouse models. To explore the differences in this side-effect of procainamide between humans and mouse models, metabolomic analysis using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOFMS) was conducted on urine samples from procainamide-treated humans, CYP2D6-humanized mice, and wild-type mice. Thirteen urinary procainamide metabolites, including nine novel metabolites, derived from P450-dependent, FMO-dependent oxidations and acylation reactions, were identified and structurally elucidated. In vivo metabolism of procainamide in CYP2D6-humanized mice as well as in vitro incubations with microsomes and recombinant P450s suggested that human CYP2D6 plays a major role in procainamide metabolism. Significant differences in N-acylation and N-oxidation of the drug between humans and mice largely account for the interspecies differences in procainamide metabolism. Significant levels of the novel N-oxide metabolites produced by FMO1 and FMO3 in humans might be associated with the development of procainamide-induced systemic lupus erythematosus. Observations based on this metabolomic study offer clues to understanding procainamide-induced lupus in humans and the effect of P450s and FMOs on procainamide N-oxidation.