Mo
MA

Modelli   Matematici per
 le Applicazioni

Dipartimento di Matematica, Sapienza, Università di Roma

Seminari 2017

Torna ai seminari dell'anno corrente

24 novembre

ore 12.00-14.00

Aula Consiglio
Luca Giomi


Active fludis: from liquid crystals to living systems


Colonies of motile microorganisms, the cytoskeleton and its components, cells and tissues have much in common with soft condensed matter systems (i.e. liquid crystals, amphiphiles, colloids etc.), but also exhibit behaviors that do not appear in inanimate matter and that are crucial for biological functions. These unique properties arise when the constituent particles are active: they consume energy from internal and external sources and dissipate it by moving through the medium they inhabit. In this talk I will give a brief introduction to the notion of “active matter” and present some recent results on the hydrodynamics of active nematics suspensions in two dimensions.

27 ottobre

ore 12.00-14.00

Aula Consiglio
Barbara Mazzolai


New frontiers in biology based robotics


Can Nature improve technology? What is the link between living systems and robots?
giving way to a series of innovative robotic solutions assisting and supporting today’s society. A bioinspired approach needs a deep understanding of the selected biological models in order to extract the key features relevantRobots today are expected to operate in a variety of scenarios, being able to cope with uncertain situations and to react quickly to changes in the environment. In this scenario a strong relationship between Nature and technology plays a major role, with the winning approach of evaluating natural systems to abstract principles for new designs. Bioinspired soft robotics is a worldwide known paradigm to develop new solutions for science and technology, for designing robotic systems able to imitate the biological counterpart in some specific functions. Such biological principles traditionally originate from animal models for robots that can walk, swim, crawl, or fly. Recently, engineers, material and computer scientists have also increased their interest in plants, as a new model for developing robots and ICT solutions. In this talk I will present some scientific and technological challenges coming from both animals and plants. I will compare ideas, biological features, and technological translations coming from these two Kingdoms and related to areas of interest in robotics: movement, sensing and control.

26 maggio

ore 12.00-14.00

Aula Consiglio
Roberto Di Leonardo


The Physics and Engineering of Active Matter


Dense suspensions of swimming bacteria display striking motions that look extremely vivid when compared to the thermal agitation of colloidal particles of comparable size. These suspensions belong to a wider class of non-equilibrium systems that are now collectively referred to as active matter. Research in active matter physics deals with the fundamental aspects underlying some distinctive properties of these systems, such as the emergence of collective behavior and rectification phenomena. From a more engineering perspective, however, active matter can be looked at as a special kind of fuel: a small droplet of an active fluid can be used to propel micro-machines inside miniaturized chips, with no need of external driving fields or control. Using advanced tools for 3D optical imaging, manipulation and fabrication we study complex phenomena in active matter with direct and quantitative methods. I will review our recent work in this direction, from off-equilibrium transport and stationary states in active matter to the use of genetically engineered bacteria as controllable propellers for synthetic micro-machines.

7 aprile

ore 12.00-14.00

Aula Consiglio
Elena Agliari


A few steps in artificial intelligence


Artificial Intelligence (AI) has by now become pervasive in our every day life. In this seminar I will provide a very basic introduction to AI, reviewing the underlying ideas and the main models. These are inspired by advances in neuroscience and are based on the interpretation of information processing and communication patterns in a nervous system.
I will especially focus on models designed for accomplishing two special tasks, that is, "learning" and "retrieval". Briefly, the former is the ability to improve the performance through experience, the latter is the ability to exploit the information previously learnt. These smart capabilities emerge as collective features of network models based on elementary units (i.e., suitably stilyzed neurons), that interact each other in a dense, frustrated and non-linear way.
Finally, I will introduce the so-called deep learning algorithms, which is the subject of frontier AI research nowadays: these algorithms use a cascade of many layers of elementary units, whence they achieve by far better perfomances in terms of accuracy and of manageable information complexity. 

3 marzo

ore 12.00-14.00

Aula Consiglio
Mariano Bizzarri


Cell fate specification: global vs local control rules, i.e., instructive vs permissive models


The process of lineage specification is fundamental to the development and maintenance of tissues in multicellular organisms. An unsolved question is whether molecular cues such as growth factors actively push multipotent progenitors to commit to a particular lineage according to the so-called ‘instructive’ model. The opposite view posits that molecular cues simply support the survival and proliferation of cells that have already committed to a specific lineage by cell intrinsic agency or by environmental physical cues, in agreement with the ‘selective/permissive’ model. Ectopic-expression experiments have supported the instructive capacity of specific cytokines, even if a number of artifacts biased these models. Indeed, exposure to growth factors may have only an ‘enabling’ rather than an inductive role during cell fate specification. For instance, in microgravity conditions spontaneous, phenotypic determination occurs independently from any biochemical ‘signal’ that could act as ‘instructive’ cue, while the promoting cell fate transition occurs once the gravity constraint has been ‘wiped out’. Indeed, a cell population requires proper physical constraints to be committed towards a specific differentiating pathway. In absence of such physical cues, the intrinsic biological ‘variability’ cannot be properly ‘selected and canalized’ into a specific phenotype. We proposed an integrated model based on top-down causation processes borrowed from microgravity-based experiments, were system’s global factors show to be instrumental in shaping both morphology and function of lower constituents. Interactions among different levels is likely to occur according to nonlinear dynamics, involving biophysical and molecular cues. Cell fate transition, in both normal and pathological condition (as for cancer), may be framed according to the non-equilibrium thermodynamics. In agreement with this paradigm, the phenotypic determination may be represented by a Waddington’s landscape, where both irreversible and irreversible transition can happen. Within this perspective, cancer development can be viewed as a phenotypic differentiation ‘gone awry’, but still ‘reversible’ when different global constraints are modified. Yet, proper modelling as well as mathematical analysis of such process still awaits a compelling conceptualization.

27 gennaio

ore 12.00-14.00

Aula Consiglio
Loredana Santo


Shape Memory Polymer Composites for Aerospace Applications


Shape memory polymers and their composites (SMPs and SMPCs) belong to a new class of smart materials, which can have interesting applications as expandable/deployable structures and light actuators. In particular, SMPCs combine typical mechanical and functional properties of composites with shape memory properties. Such properties can be given to composite materials and structures by using shape memory polymer (SMP) matrices or integratingShape memory polymers and their composites (SMPs and SMPCs) belong to a new class of smart materials, which parts made of SMPs. In the case of integration, SMPC laminate can be obtained by adding a shape memory layer in form of powder between the two composite skins or flexible composite skins can be applied over a shape memory foam core obtaining composite sandwich. As shape memory materials, SMPCs can respond to specific external stimulus changing their configuration and then remember the original shape.