2017Poster in Atti di convegnometadata only access
Large-scale brain integration patterns differ in focused-attention and open-monitoring meditation
Daphné BertrandDubois
;
David Meunier
;
Annalisa Pascarella
;
Vittorio Pizzella
;
Laura Marzetti
;
Karim Jerbi
An important process underlying meditation and its benefits involves the regulation of attention. Although the two main meditation categories - open-monitoring meditation (OMM) and focused-attention meditation (FAM) - are associated with different benefits and attentional processes, direct comparisons between the attentional neural mechanism of FAM and OMM are rare. This study uses magnetoencephalography (MEG) recordings in 12 expert meditators to compare FAM and OMM by assessing (i) source spectral power, (ii) seed-based functional connectivity of key regions in attention, (including anterior cingulate cortex, dorsolateral prefrontal cortex and the thalamus) and (iii) graph theory metrics that describe brain-wide efficiency of information processing. We reconstructed the source space using minimum norm estimate and computed spectral power and functional connectivity in multiple frequency bands (delta, theta, alpha, beta, gamma) using a custom-designed python-based MEG analysis pipeline (NeuroPycon). The results reveal unique patterns of neural processes specific to FAM or OMM. Among other things, compared to FAM, OMM appears to be characterized by enhanced small-world network properties. By contrast, FAM exhibits greater functional connectivity between the anterior cingulate cortex and frontal regions. These findings shed light onto the mechanisms that potentially mediate the different behavioral and attentional capacities associated with each of the two meditation techniques. Our results are discussed in the context of previous behavioral and fMRI studies on meditation and attention.
Under the current deluge of omics, module networks distinctively emerge as methods capable of not only identifying inherently coherent groups (modules), thus reducing dimensionality, but also hypothesizing cause-effect relationships between modules and their regulators. Module networks were first designed in the transcriptomic era and further exploited in the multi-omic context to assess (for example) miRNA regulation of gene expression. Despite a number of available implementations, expansion of module networks to other omics is constrained by a limited characterization of the solutions' (modules plus regulators) accuracy and stability-an immediate need for the better characterization of molecular biology complexity in silico. We hence carefully assessed for LemonTree-a popular and open source module network implementation-the dependency of the software performances (sensitivity, specificity, false discovery rate, solutions' stability) on the input parameters and on the data quality (sample size, expression noise) based on synthetic and real data. In the process, we uncovered and fixed an issue in the code for the regulator assignment procedure. We concluded this evaluation with a table of recommended parameter settings. Finally, we applied these recommended settings to gut-intestinal metagenomic data from rheumatoid arthritis patients, to characterize the evolution of the gut-intestinal microbiome under different pharmaceutical regimens (methotrexate and prednisone) and we inferred innovative clinical recommendations with therapeutic potential, based on the computed module network.
Motivation: Cells derived by cellular engineering, i.e. differentiation of induced pluripotent stem cells and direct lineage reprogramming, carry a tremendous potential for medical applications and in particular for regenerative therapies. These approaches consist in the definition of lineage-specific experimental protocols that, by manipulation of a limited number of biological cues-niche mimicking factors, (in) activation of transcription factors, to name a few-enforce the final expression of cell-specific (marker) molecules. To date, given the intricate complexity of biological pathways, these approaches still present imperfect reprogramming fidelity, with uncertain consequences on the functional properties of the resulting cells. Results: We propose a novel tool eegc to evaluate cellular engineering processes, in a systemic rather than marker-based fashion, by integrating transcriptome profiling and functional analysis. Our method clusters genes into categories representing different states of (trans) differentiation and further performs functional and gene regulatory network analyses for each of the categories of the engineered cells, thus offering practical indications on the potential lack of the reprogramming protocol.
DEFINED FACTORS; TRANSCRIPTION FACTORS; ENDOTHELIAL-CELLS; DIRECT CONVERSION; STEM-CELLS; FIBROBLASTS; DIFFERENTIATION; IDENTITY; NETWORKS; NEURONS
In this paper the Wiener estimator for signal-denoising is generalized to
finite frame operators. In particular, a two-stage procedure which results
in a non-linear and non-diagonal estimator is proposed. Advantages and
disadvantages with respect to the classical Wiener estimator used with
orthonormal basis operator are discussed showing results on standard and
real test signals.
The numerical study presented in Part I (Dubbioso et al., 2017) on the bearing loads developed by the propellers
of a twin screw model during quasi-steady conditions is extended to transient maneuvers. In the previous study,
numerical simulations highlighted that the hydrodynamic loads might experience significant peak at moderate
turning rates due to complex interaction of the propeller with the wake. In the present paper, the complete turning
circle maneuver at ? 1/4 35 ? at Fr 1/4 0:265 is numerically simulated in order to analyze the character of the blade
loads during the transient phases after the actuation of the rudder (start and pull-out). The analysis shows that the
overall degradation of the propeller performance may occur also at kinematic conditions weaker than those
usually considered as the most critical ones (in general, tight maneuvers); therefore, these conditions should be
accounted for also in the early design phases.
Infection by Leishmania protozoan parasites can cause a variety of disease outcomes in humans and other mammals, from single self-healing cutaneous lesions to a visceral dissemination of the parasite. The correlation between chronic lesions and ecto-nucleotidase enzymes activity on the surface of the parasite is addressed here using damage caused in epithelial cells by nitric oxide. In order to explore the role of purinergic metabolism in lesion formation and the outcome of the infection, we implemented a cellular automata/lattice gas model involving major immune characters (Th1 and Th2 cells, IFN-gamma, IL-4, IL-12, adenosine-Ado-, NO) and parasite players for the dynamic analysis of the disease progress. The model were analyzed using partial ranking correlation coefficient (PRCC) to indicate the components that most influence the disease progression. Results show that low Ado inhibition rate over Th-cells is shared by L. major and L. braziliensis, while in L. amazonensis infection the Ado inhibition rate over Th-cells reaches 30%. IL-4 inhibition rate over Th-cell priming to Th1 independent of IL-12 are exclusive of L. major. The lesion size and progression showed agreement with published biological data and the model was able to simulate cutaneous leishmaniasis outcomes. The sensitivity analysis suggested that Ado inhibition rate over Th-cells followed by Leishmania survival probability were the most important characteristics of the process, with PRCC of 0.89 and 0.77 respectively. The simulations also showed a non-linear relationship between Ado inhibition rate over Th-cells and lesion size measured as number of dead epithelial cells. In conclusion, this model can be a useful tool for the quantitative understanding of the immune response in leishmaniasis.
leishmaniasis
cutaneous
adenosine (Ado)
model
lattice-gas
inflammation
A comprehensive approach to Sobolev-type embeddings, involving arbitrary rearrangement-
invariant norms on the entire Euclidean space R^n, is offered. In particular, the optimal target space in
any such embedding is exhibited. Crucial in our analysis is a new reduction principle for the relevant
embeddings, showing their equivalence to a couple of considerably simpler one-dimensional inequalities.
Applications to the classes of the Orlicz-Sobolev and the Lorentz-Sobolev spaces are also presented.
These contributions fill in a gap in the existing literature, where sharp results in such a general setting
are only available for domains of finite measure.
A comprehensive approach to Sobolev-type embeddings, involving arbitrary rearrangement-
invariant norms on the entire Euclidean space R^n, is offered. In particular, the optimal target space in
any such embedding is exhibited. Crucial in our analysis is a new reduction principle for the relevant
embeddings, showing their equivalence to a couple of considerably simpler one-dimensional inequalities.
Applications to the classes of the Orlicz-Sobolev and the Lorentz-Sobolev spaces are also presented.
These contributions fill in a gap in the existing literature, where sharp results in such a general setting
are only available for domains of finite measure.
Acceleration of leukocytes' epigenetic age as an early tumor- and sex-specific marker of breast and colorectal cancer
Durso Danielle Fernandes
;
Bacalini Maria Giulia
;
Sala Claudia
;
Pirazzini Chiara
;
Marasco Elena
;
Bonafe Massimiliano
;
do Valle Italo Faria
;
Gentilini Davide
;
Castellani Gastone
;
Caetano Faria Ana Maria
;
Franceschi Claudio
;
Garagnani Paolo
;
Nardini Christine
Changes in blood epigenetic age have been associated with several pathological conditions and have recently been described to anticipate cancer development. In this work, we analyze a publicly available leukocytes methylation dataset to evaluate the relation between DNA methylation age and the prospective development of specific types of cancer. We calculated DNA methylation age acceleration using five state-of-the-art estimators 9three multi-site: Horvath, Hannum, Weidner; and two CpG specific: ELOV2 and FHL2) in a cohort including 845 subjects from the EPIC-Italy project and we compared 424 samples that remained cancer-free over the approximately ten years of follow-up with 235 and 166 subjects who developed breast and colorectal cancer, respectively. We show that the epigenetic age estimated from blood DNA methylation data is statistically significantly associated to future breast and male colorectal cancer development. These results are corroborated by survival analysis that shows significant association between age acceleration and cancer incidence suggesting that the chance of developing age-related diseases may be predicted by circulating epigenetic markers, with a dependence upon tumor type, sex and age estimator. These are encouraging results towards the non-invasive and perspective usage of epigenetic biomarkers.
Link prediction aims at detecting missing, spurious or evolving links in a network, based on the topological information and/or nodes attributes of the network. Under the assumption that the likelihood of the existence of a link between two nodes can be captured by nodes similarity, several methods have been proposed to compute similarity directly or indirectly, with information on node degree. However, correctly predicting links is also crucial in revealing the link formation mechanisms and thus in providing more accurate modeling for networks. We here propose a novel method to predict links by incorporating stochastic-block-model link generating mechanisms with node degree. The proposed method first recovers the underlying block structure of a network by modularity-based belief propagation, and based on the recovered block structural information it models the link likelihood between two nodes to match the degree sequence of the network. Experiments on a set of real-world networks and synthetic networks generated by stochastic block model show that our proposed method is effective in detecting missing, spurious or evolving links of networks that can be well modeled by a stochastic block model. This approach efficiently complements the toolbox for complex network analysis, offering a novel tool to model links in stochastic block model networks that are fundamental in the modeling of real world complex networks.
belief propagation
complex network
link prediction
modularity
We propose a multi-component discrete Boltzmann model (DBM) for premixed, nonpremixed, or partially premixed nonequilibrium reactive flows. This model is suitable for both subsonic and supersonic flows with or without chemical reaction and/or external force. A two-dimensional sixteen-velocity model is constructed for the DBM. In the hydrodynamic limit, the DBM recovers the modified Navier-Stokes equations for reacting species in a force field. Compared to standard lattice Boltzmann models, the DBM presents not only more accurate hydrodynamic quantities, but also detailed nonequilibrium effects that are essential yet long-neglected by traditional fluid dynamics. Apart from nonequilibrium terms (viscous stress and heat flux) in conventional models, specific hydrodynamic and thermodynamic nonequilibrium quantities (high order kinetic moments and their departure from equilibrium) are dynamically obtained from the DBM in a straightforward way. Due to its generality, the developed methodology is applicable to a wide range of phenomena across many energy technologies, emissions reduction, environmental protection, mining accident prevention, chemical and process industry.
We present an entropic version of the lattice Boltzmann pseudo-potential approach for the simulation of multiphase flows. The method is shown to correctly simulate the dynamics of impinging droplets on hydrophobic surfaces and head-on and grazing collisions between droplets, at Weber and Reynolds number regimes not accessible to previous pseudo-potential methods at comparable resolution.
Despite a long record of intense effort, the basic mechanisms by which dissipation emerges from the microscopic dynamics of a relativistic fluid still elude complete understanding. In particular, several details must still be finalized in the pathway from kinetic theory to hydrodynamics mainly in the derivation of the values of the transport coefficients. In this paper, we approach the problem by matching data from lattice-kinetic simulations with analytical predictions. Our numerical results provide neat evidence in favor of the Chapman-Enskog [The Mathematical Theory of Non-Uniform Gases, 3rd ed. (Cambridge University Press, Cambridge, U.K., 1970)] procedure as suggested by recent theoretical analyses along with qualitative hints at the basic reasons why the Chapman-Enskog expansion might be better suited than Grad's method [Commun. Pure Appl. Math. 2, 331 (1949)0010-364010.1002/cpa.3160020403] to capture the emergence of dissipative effects in relativistic fluids.
We present a systematic derivation of relativistic lattice kinetic equations for finite-mass particles, reaching close to the zero-mass ultrarelativistic regime treated in the previous literature. Starting from an expansion of the Maxwell-Juttner distribution on orthogonal polynomials, we perform a Gauss-type quadrature procedure and discretize the relativistic Boltzmann equation on space-filling Cartesian lattices. The model is validated through numerical comparison with standard tests and solvers in relativistic fluid dynamics such as Boltzmann approach multiparton scattering and previous relativistic lattice Boltzmann models. This work provides a significant step towards the formulation of a unified relativistic lattice kinetic scheme, covering both massive and near-massless particles regimes.
Copepods encounter rates from a model of escape jump behaviour in turbulence
Ardeshiri H
;
Schmitt F G
;
Souissi S
;
Toschi F
;
Calzavarini E
A key ecological parameter for planktonic copepod studies is their encounter rates within the same population as well as with other species. The encounter rate is partly determined by copepod's swimming behaviour and is strongly influenced by turbulence of the surrounding environment. A distinctive feature of copepods' motility is their ability to perform quick displacements, often termed jumps, by means of powerful swimming strokes. Such a reaction has been associated to an escape behaviour from flow disturbances due to predators or other external signals. In the present study, we investigate the encounter rates of copepods of the same species in a developed turbulent flow with intensities comparable to those encountered in their natural habitat. This is done by means of a Lagrangian copepod (LC) model that mimics the jump escape reaction behaviour from localized high-deformation rate fluctuations in the turbulent flows. Our analysis shows that the encounter rate for copepods of typical perception radius of similar to eta, where eta is the dissipative scale of turbulence, can be increased by a factor up to similar to 10(2) compared to that experienced by passively transported fluid tracers of the same size. Furthermore, we address the effect of a minimal waiting time between consecutive jumps. It is shown that any encounter-rate enhancement is lost if such time goes beyond the dissipative time-scale of turbulence, tau(eta). Because typically in the ocean eta similar to 1mm and tau(eta) similar to 1s, this provides stringent constraints on the turbulent-driven enhancement of contact-rate due to a purely mechanical induced escape reaction. The implications of our results in the context of copepod ecology copepods are discussed.
turbulence
encounter rate
Lagrangian copepod model
Atmospheric emissions of carbon tetrachloride (CCl4) are regulated by the Montreal Protocol due to its role as a strong ozone-depleting substance. The molecule has been the subject of recent increased interest as a consequence of the so-called "mystery of CCl4", the discrepancy between atmospheric observations and reported production and consumption. Surface measurements of CCl4 atmospheric concentrations have declined at a rate almost 3 times lower than its lifetime-limited rate, suggesting persistent atmospheric emissions despite the ban. In this paper, we study CCl4 vertical and zonal distributions in the upper troposphere and lower stratosphere (including the photolytic loss region, 70-20 hPa), its trend, and its stratospheric lifetime using measurements from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), which operated onboard the ENVISAT satellite from 2002 to 2012. Specifically, we use the MIPAS data product generated with Version 7 of the Level 2 algorithm operated by the European Space Agency.
The CCl4 zonal means show features typical of long-lived species of anthropogenic origin that are destroyed primarily in the stratosphere, with larger quantities in the troposphere and a monotonic decrease with increasing altitude in the stratosphere. MIPAS CCl4 measurements have been compared with independent measurements from other satellite and balloon-borne remote sounders, showing a good agreement between the different datasets.
CCl4 trends are calculated as a function of both latitude and altitude. Negative trends of about -10 to -15 pptv decade-1 (-10 to -30 % decade-1) are found at all latitudes in the upper troposphere-lower stratosphere region, apart from a region in the southern midlatitudes between 50 and 10 hPa where the trend is positive with values around 5-10 pptv decade-1 (15-20 % decade-1). At the lowest altitudes sounded by MIPAS, we find trends consistent with those determined on the basis of long-term ground-based measurements (-10 to -13 pptv decade-1). For higher altitudes, the trend shows a pronounced asymmetry between the Northern and Southern hemispheres, and the magnitude of the decline rate increases with altitude. We use a simplified model assuming tracer-tracer linear correlations to determine CCl4 lifetime in the lower stratosphere. The calculation provides a global average lifetime of 47 (39-61) years, considering CFC-11 as the reference tracer. This value is consistent with the most recent literature result of 44 (36-58) years.
Book of proceedings of the workshop MASCOT 2015, 14th Meeting on Applied Scientific Computing and Tools, held in Rome on June 9 - 12, 2015, at IAC (CNR).
The program of the meeting, in each presentations, and the contents of this volume, in each paper, show advanced expertise matured in several countries, both in west and east Europe and overseas, all speakers and authors coming from high qualified universities and research centers. The large spectrum of topics approached by the applied scientific computing works deals with numer- ical methods and computational tools (i.e. approximation theory, grid genera- tion, unstructured grids, ...) for modelling a variety of fundamental problems, approximate and simulate important applicative problems in: fluid dynamics, granular materials and materials with memory, chemotaxis, crowd dynamics, environmental problems, urban heat islands, grinding wheels, imaging, image segmentation and data analysis.
Raccolta degli atti del workshop internazionale MASCOT 2015, 14th Meeting on Applied Scientific Computing and Tools, tenutosi a Roma nel periodo 9 - 12 giugno 2015 presso l'IAC (CNR).
This is the web-site of the workshop 'Mathematical Approach to Climate Change Impacts" held in Rome at INDAM on March 13 - 17, 2017, organized by Piermarco Cannarsa (uni. Tor Vergata), Daniela Mansutti (IAC - CNR) and Antonello Provenzale (IGG - CNR). Beside the program and other practical aspects related to the conference days, it exhibits the book of abstracts and, thanks to the generosity of the lecturers, the slides of each presentation (plenary, contributing and tutorial), which make it very rich of scientific information.