Keller-Segel system, chemotaxis and applications to a mathematical model for Alzheimer's disease

In questa tesi viene presentato il modello di Keller-Segel per la chemiotassi, un sistema di tipo parabolico-ellittico che appare nella descrizione di molti fenomeni in ambito biologico e medico. Viene mostrata l'esistenza globale della soluzione debole del modello, per dati iniziali sufficientemente piccoli in dimensione N>2. La scelta di dati iniziali abbastanza grandi invece può causare il blow-up della soluzione e viene mostrato sotto quali condizioni questo si verifica. Infine il modello della chemiotassi è stato applicato per descrivere una fase della malattia di Alzheimer ed è stata effettuata un'analisi di stabilità del sistema.

Italian American women in Helen Barolini's Umbertina

This essay analyzes the story and the culture of Italian American women, in particular how they are treated in the novel "Umbertina" by Helen Barolini. The essay first introduces briefly the causes of the great migration and the conditions of immigrants in the US. Then the focus moves on the analysis of the main themes that belong to the genre of Italian American literature. After having shortly treated the biography of Helen Barolini and a general presentation of her novel Umbertina, the essay goes on with the description of its three Italian American female characters and, in particular, of what it meant to be both immigrants and women, together with all the interior and generational conflicts they had to face in order to accept their new hybrid identity. An analysis of some meaningful metaphorical objects in the novel, such as the tin heart and the bedspread, the metaphor of Persephone and of the threshold conclude the essay. Through the analysis of the story of Umbertina, this essay wants to show how migration can lead to a displacement and the kind of journey people had to undertake in order to overcome the conflicts deriving from their belonging to an in-between culture and to accept their hybrid identity.