30 Marzo, 2015 14:30

Approximated Lax Pair for reduced order modeling. Application to electrophysiology

J.F. Gerbeau, Inria Paris

Aula Saleri VI Piano MOX Dipartimento di Matematica POLITECNICO DI MILANO

abstract

abstract

A reduced-order model algorithm, called ALP, is proposed to solve nonlinear evolution partial differential equations. It is based on approximations of generalized Lax pairs. Contrary to other reduced-order methods, like Proper Orthogonal Decomposition, the basis on which the solution is searched for evolves in time according to a dynamics specific to the problem. It is therefore well-suited to solving problems with progressive front or wave propagation. Another difference with other reduced-order methods is that it is not based on an off-line / on-line strategy. Numerical examples are shown for the FKPP equations and for the bidomain model of electrophysiology. This work was done in collaboration with Damiano Lombardi and Elisa Schenone.

contact: christian.vergara@polimi.it

25 Marzo, 2015 12:15

Seminari di Cultura Matematica

Mente e creatività

Piero De Giacomo, Università di Bari

aula B21, edificio 14, Campus Bonardi

A reduced-order model algorithm, called ALP, is proposed to solve nonlinear evolution partial differential equations. It is based on approximations of generalized Lax pairs. Contrary to other reduced-order methods, like Proper Orthogonal Decomposition, the basis on which the solution is searched for evolves in time according to a dynamics specific to the problem. It is therefore well-suited to solving problems with progressive front or wave propagation. Another difference with other reduced-order methods is that it is not based on an off-line / on-line strategy. Numerical examples are shown for the FKPP equations and for the bidomain model of electrophysiology. This work was done in collaboration with Damiano Lombardi and Elisa Schenone.

contact: christian.vergara@polimi.it

19 Marzo, 2015 11:00

MOX Seminar

Pointing in an undergraduate abstract algebra lecture: Interface between speaking and writing

Nathalie Sinclair, Simon Fraser University a Vancouver

Aula Saleri VI Piano Dipartimento di Matematica POLITECNICO DI MILANO

abstract

abstract

The typical teaching format of undergraduate mathematics classrooms is the lecture, which commonly involves a large amount of talking and writing on the board. In addition to speaking and writing, professors use their hands to communicate. In this talk, I focus specifically on the use of the hand (and fingers) to point. In particular, I will examine the acts of pointing made by a a professor in a third-year group theory lecture and discuss their function. I will show how they form a central component in communication, particularly in terms of (1) bringing mathematical objects into being, (2) relating these objects to each other and (3) connecting the spoken with the written and drawn.

contact:chiara.andra@polimi.it

18 Marzo, 2015 12:15

Seminari di Cultura Matematica

Maksimovich. La storia di Bruno Pontecorvo

Giuseppe Mussardo, SISSA, Trieste

aula B21, edificio 14, Campus Bonardi

The typical teaching format of undergraduate mathematics classrooms is the lecture, which commonly involves a large amount of talking and writing on the board. In addition to speaking and writing, professors use their hands to communicate. In this talk, I focus specifically on the use of the hand (and fingers) to point. In particular, I will examine the acts of pointing made by a a professor in a third-year group theory lecture and discuss their function. I will show how they form a central component in communication, particularly in terms of (1) bringing mathematical objects into being, (2) relating these objects to each other and (3) connecting the spoken with the written and drawn.

contact:chiara.andra@polimi.it

11 Marzo, 2015 11:45

Seminari di Cultura Matematica

I veri e i falsi accordi sul clima tra scienza, economia e politica

Franco Foresta Martin, Giornalista scientifico

aula Rogers, Campus Leonardo

The typical teaching format of undergraduate mathematics classrooms is the lecture, which commonly involves a large amount of talking and writing on the board. In addition to speaking and writing, professors use their hands to communicate. In this talk, I focus specifically on the use of the hand (and fingers) to point. In particular, I will examine the acts of pointing made by a a professor in a third-year group theory lecture and discuss their function. I will show how they form a central component in communication, particularly in terms of (1) bringing mathematical objects into being, (2) relating these objects to each other and (3) connecting the spoken with the written and drawn.

contact:chiara.andra@polimi.it

11 Marzo, 2015 15:00

Sezione di Probabilità Quantistica

Relativistic Causality and Local Disentanglement in Quantum Field Theory

Giovanni Valente, University of Pittsburgh

Aula Consiglio VII piano, Dipartimento di Matematica, ed. 14, Campus Leonardo

abstract

abstract

La nozione di entanglement fra sistemi quantistici separati pone due problemi fondamentali in filosofia della meccanica quantistica. Primo, le correlazioni non-locali che ne derivano sembrano determinare un conflitto con la condizione di causalità relativistica, che implica che processi causali non possano propagarsi ad una velocità superiore a quella della luce, sollevando cosí una questione di incompatibilità con la teoria della relatività speciale di Einstein. Secondo, la presenza dell’entanglement sembra pregiudicare la possibilità di ottenere una suddivisione del mondo microscopico in sistemi fisici indipendenti. In questo seminario, si discuteranno tali problemi nel contesto della formulazione algebrica della teoria quantistica dei campi. Si inizierà mostrando come si possa derivare un teorema sull’impossibilità di inviare messaggi superluminali sulla base di operazioni locali. Successivamente, si dimostrerà l’esistenza di operazioni locali che hanno l’effetto di distruggere l’entanglement fra campi quantistici separati, soddisfacendo in tal modo ad una condizione necessaria per la loro indipendenza reciproca.

10 Marzo, 2015 11:30

MOX Seminar

Accurate Typing of SHORT Tandem Repeats from genome-wide sequencing data and its applications

Kateryna Makova, Pentz Professor of Biology -The Pennsylvania State University

Aula Saleri VI piano del Dipartimento di Matematica - MOX - Politecnico di Milano

abstract

abstract

Short Tandem Repeats (STRs) are implicated in dozens of human genetic diseases and contribute significantly to genome variation and instability. Yet profiling STRs from short-read sequencing data is challenging because of their high sequencing error rate. Here we developed STR-FM, Short Tandem Repeat profiling using Flank-based Mapping, a computational pipeline that can detect the full spectrum of STR alleles from short-read data, can adapt to emerging read-mapping algorithms, and can be applied to heterogeneous genetic samples (e.g., tumors, viral populations, and genomes of organelles). We used STR-FM to study STR error rates and patterns in publicly available human, and in-house generated ultra-deep plasmid, sequencing datasets. We discovered that STRs sequenced with a PCR-free protocol have up to 9-fold fewer errors than those sequenced with a PCR-containing protocol. We constructed an error correction model for genotyping STRs that can assign genotypes correctly to 98-100% of STRs and can distinguish heterozygous alleles containing STRs with consecutive repeat numbers. Applying our model and pipeline to Illumina sequencing data with 100-bp reads, we could confidently genotype several disease-related long trinucleotide STRs. Utilizing this pipeline, for the first time we determined the genome-wide STR germ-line mutation rate from a deeply sequenced human pedigree. More mutations originated in the male germ line. Additionally, we built a tool that recommends minimum sequencing depth for accurate STR genotyping, depending on repeat length of interest and sequencing read length. The required read depth increases with STR length and is lower for a PCR-free protocol. This suite of tools addresses the pressing challenges surrounding STR genotyping, and thus is of wide interest to researchers investigating disease-related STRs and STR evolution.

contact: anna.paganoni@polimi.it

6 Marzo, 2015 14:00

Sezione di Calcolo delle Variazioni ed Equazioni Differenziali

Exponential stability for thermoelastic Bresse systems with nonclassical heat conduction

Filippo Dell' Oro, Institute of Mathematics of the Academy of Sciences of the Czech Republic

Aula seminari III piano

abstract

abstract

We provide a comprehensive stability analysis of the thermoelastic Bresse system (also known as the circular arch problem). In particular, assuming a temperature evolution of Gurtin-Pipkin type, we establish a necessary and sufficient condition for exponential stability in terms of the structural parameters of the problem. As a byproduct, a complete characterization of the longtime behavior of Bresse-type systems with Fourier, Maxwell-Cattaneo and Coleman-Gurtin thermal laws is obtained.

6 Marzo, 2015 14:00

MOX Seminar

La tutela brevettuale dei metodi matematici

Roberto Tiezzi - Massimo Barbieri, Servizio Valorizzazione della Ricerca (TTO) POLITECNICO DI MILANO

Aula Saleri VI piano del Dipartimento di Matematica - MOX - Politecnico di Milano

abstract

abstract

N.A.

5 Marzo, 2015 15:00

Seminari FDS

Cronache dai Ghiacci: 90 giorni in antartide

Chiara Montanari, Politecnico di Milano

Aula Consiglio, 7° piano, edificio 14 Nave – Via Bonardi, 9 – Milano

abstract

abstract

Come si vive in una base di ricerca in Antartite, a -50 °C e 4000m di altitudine?
Concordia è una base di ricerca italo-francese prossima al Polo Sud. E’ situata su un altipiano di ghiaccio a 1.200 km dalla costa: un luogo isolato da tutto, un ambiente ostile e gelido, dove le condizioni climatiche impediscono qualsiasi tipo di vita. Ricercatori, biologi, climatologi di tutto il mondo vi studiano lo stato dei ghiacci e del pianeta. Organizzare la vita quotidiana non è semplice: l’approvvigionamento in viveri, materiali e carburante dipende dall’arrivo del convoglio via terra, la “traversa” , ma in Antartide nulla è più imprevedibile del meteo, e l’attesa può essere snervante e trasformarsi in un incubo. Ci sono, poi, la gestione delle emergenze logistiche e sanitarie e l’inevitabile conflittualità che esse generano. La gestione dei rapporti personali in un microcosmo asfittico, dove non vi è la possibilità di isolarsi né di allontanarsi, è infatti l’altra dura prova a cui sono sottoposti gli abitanti della base.

Nel 2013 Chiara Montanari è tornata alla stazione Concordia per la sua quarta spedizione in Antartide, questa volta, come responsabile della logistica. Vi ha trascorso i tre mesi dell’estate australe, quando il sole non tramonta mai. Per tutta la sua permanenza ha tenuto un diario, che quest’anno si è trasformato in un libro.

Con questa presentazione, ricca di immagini e filmati, ci propone uno squarcio di vita e condizioni di ricerca decisamente fuori dal comune.