1,828 research outputs found
Emergence and persistence of communities in coevolutionary networks
We investigate the emergence and persistence of communities through a
recently proposed mechanism of adaptive rewiring in coevolutionary networks. We
characterize the topological structures arising in a coevolutionary network
subject to an adaptive rewiring process and a node dynamics given by a simple
voterlike rule. We find that, for some values of the parameters describing the
adaptive rewiring process, a community structure emerges on a connected
network. We show that the emergence of communities is associated to a decrease
in the number of active links in the system, i.e. links that connect two nodes
in different states. The lifetime of the community structure state scales
exponentially with the size of the system. Additionally, we find that a small
noise in the node dynamics can sustain a diversity of states and a community
structure in time in a finite size system. Thus, large system size and/or local
noise can explain the persistence of communities and diversity in many real
systems.Comment: 6 pages, 5 figures, Accepted in EPL (2014
An alternative strategy for cloning minor permeases in Aspergillus nidulans
The uapC gene was cloned by complementation of the cryosensitive phenotype of uapA mutants following the instant gene bank method. The analysis of the transformants is presented and a strategy to clone other transport related genes is proposed
General coevolution of topology and dynamics in networks
We present a general framework for the study of coevolution in dynamical
systems. This phenomenon consists of the coexistence of two dynamical processes
on networks of interacting elements: node state change and rewiring of links
between nodes. The process of rewiring is described in terms of two basic
actions: disconnection and reconnection between nodes, both based on a
mechanism of comparison of their states. We assume that the process of rewiring
and node state change occur with probabilities Pr and Pc respectively,
independent of each other. The collective behavior of a coevolutionary system
can be characterized on the space of parameters (Pr, Pc). As an application,
for a voterlike node dynamics we find that reconnections between nodes with
similar states lead to network fragmentation. The critical boundaries for the
onset of fragmentation in networks with different properties are calculated on
this space. We show that coevolution models correspond to curves on this space
describing functional relations between Pr and Pc. The occurrence of a
one-large-domain phase and a fragmented phase in the network is predicted for
diverse models, and agreement is found with some earlier results. The
collective behavior of system is also characterized on the space of parameters
for the disconnection and reconnection actions. In a region of this space, we
find a behavior where different node states can coexist for very long times on
one large, connected network.Comment: 6 pages, 6 figure
METRIC DOCUMENTATION OF CULTURAL HERITAGE: RESEARCH DIRECTIONS FROM THE ITALIAN GAMHER PROJECT
GAMHer is a collaborative project that aims at exploiting and validating Geomatics algorithms, methodologies and procedures in the framework of new European regulations, which require a more extensive and productive use of digital information, as requested by the Digital Agenda for Europe as one of the seven pillars of the Europe 2020 Strategy. To this aim, GAMHer focuses on the need of a certified accuracy for surveying and monitoring projects with photogrammetry and laser scanning technologies, especially when used in a multiscale approach for landscape and built heritage documentation, conservation, and management. The approach used follows a multi-LoD (level of detail) transition that exploits GIS systems at the landscape scale, BIM technology and "point cloud based" 3d modelling for the scale of the building, and an innovative BIM/GIS integrated approach to foster innovation, promote users' collaboration and encourage communication between users. The outcomes of GAMHer are not intended to be used only by a community of Geomatics specialists, but also by a heterogeneous user community that exploit images and laser scans in their professional activities
Chaplygin gas with non-adiabatic pressure perturbations
Perturbations in a Chaplygin gas, characterized by an equation of state , may acquire non-adiabatic contributions if spatial variations of the
parameter are admitted. This feature is shown to be related to a specific
internal structure of the Chaplygin gas. We investigate how perturbations of
this type modify the adiabatic sound speed and influence the time dependence of
the gravitational potential which gives rise to the Integrated Sachs-Wolfe
effect in the anisotropy spectrum of the cosmic microwave background.Comment: 16 pages, comments and references added, accepted for publication in
Class.Quantum Gra
Metric documentation of cultural heritage: Research directions from the Italian gamher project
GAMHer is a collaborative project that aims at exploiting and validating Geomatics algorithms, methodologies and procedures in the framework of new European regulations, which require a more extensive and productive use of digital information, as requested by the Digital Agenda for Europe as one of the seven pillars of the Europe 2020 Strategy. To this aim, GAMHer focuses on the need of a certified accuracy for surveying and monitoring projects with photogrammetry and laser scanning technologies, especially when used in a multiscale approach for landscape and built heritage documentation, conservation, and management. The approach used follows a multi-LoD (level of detail) transition that exploits GIS systems at the landscape scale, BIM technology and "point cloud based" 3d modelling for the scale of the building, and an innovative BIM/GIS integrated approach to foster innovation, promote users' collaboration and encourage communication between users. The outcomes of GAMHer are not intended to be used only by a community of Geomatics specialists, but also by a heterogeneous user community that exploit images and laser scans in their professional activities
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Unlocking value from AI in financial services: strategic and organizational tradeoffs vs. media narratives
One of the sectors that AI is expected to transform more radically is financial services. In this Chapter, first, building on the extant literature, we develop a general conceptual model of the strategic and organisational tradeoffs inherent in extracting value from AI. Second, we use a topic modelling approach on two sources of data (a âcorpusâ of articles published in the global business press and a âcorpusâ of web articles concerning AI in financial institutions located in the City of London) to identify the narratives about AI in financial services from 2013 to 2019. The comparison between our model of AI value creation and the narratives emerging from our topic models reveals a significant divide. We elaborate on the implications of this divide and we offer suggestions on how to manage AI adoption for value creation
Immunotherapy in endometrial cancer: new scenarios on the horizon
This extensive review summarizes clinical evidence on immunotherapy and targeted therapy currently available for endometrial cancer (EC) and reports the results of the clinical trials and ongoing studies. The research was carried out collecting preclinical and clinical findings using keywords such as immune environment, tumor infiltrating lymphocytes, programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) expression, immune checkpoint inhibitors, anti-PD-1/PD-L1 antibodies and othersâ on PubMed. Finally, we looked for the ongoing immunotherapy trials on ClinicalTrials.gov. EC is the fourth most common malignancy in women in developed countries. Despite medical and surgical treatments, survival has not improved in the last decade and death rates have increased for uterine cancer in women. Therefore, identification of clinically significant prognostic risk factors and formulation of new rational therapeutic regimens have great significance for enhancing the survival rate and improving the outcome in patients with advanced or metastatic disease. The identification of genetic alterations, including somatic mutations and microsatellite instability, and the definition of intracellular signaling pathways alterations that have a major role in in tumorigenesis is leading to the development of new therapeutic options for immunotherapy and targeted therapy
Dynamic motor imagery mentally simulates uncommon real locomotion better than static motor imagery both in young adults and elderly
A new form of Motor Imagery (MI), called dynamic Motor Imagery (dMI) has recently been proposed. The dMI adds to conventional static Motor Imagery (sMI) the presence of simultaneous actual movements partially replicating those mentally represented. In a previous research conducted on young participants, dMI showed to be temporally closer than sMI in replicating the real performance for some specific locomotor conditions. In this study, we evaluated if there is any influence of the ageing on dMI. Thirty healthy participants were enrolled: 15 young adults (27.1\ub13.8 y.o.) and 15 older adults (65.9\ub19.6y.o.). The performance time and the number of steps needed to either walk to a target (placed at 10m from participants) or to imagine walking to it, were assessed. Parameters were measured for sMI, dMI and real locomotion (RL) in three different locomotor conditions: forward walking (FW), backward walking (BW), and lateral walking (LW). Temporal performances of sMI and dMI did not differ between RL in the FW, even if significantly different to each other (p = 0.0002). No significant differences were found for dMI with respect to RL for LW (p = 0.140) and BW (p = 0.438), while sMI was significantly lower than RL in LW (p<0.001). The p-value of main effect of age on participants' temporal performances was p = 0.055. The interaction between age and other factors such as the type of locomotion (p = 0.358) or the motor condition (p = 0.614) or third level interaction (p = 0.349) were not statistically significant. Despite a slight slowdown in the performance of elderly compared to young participants, the temporal and spatial accuracy was better in dMI than sMI in both groups. Motor imagery processes may be strengthened by the feedback generated through dMI, and this effect appears to be unaffected by age
Coupling of bioelectrochemical toluene oxidation and trichloroethene reductive dechlorination for single-stage treatment of groundwater containing multiple contaminants
Bioremediation of groundwater contaminated by a mixture of aromatic hydrocarbons and chlorinated solvents is typically challenged because these contaminants are degraded via distinctive oxidative and reductive pathways, thus requiring different amendments and redox conditions. Here, we provided the proof-of-concept of a single-stage treatment of synthetic groundwater containing toluene and trichloroethene (TCE) in a tubular bioelectrochemical reactor, known as a âbioelectric wellâ. Toluene was degraded by a microbial bioanode (up to 150 ÎŒmol Lâ1 dâ1) with a polarized graphite anode (+0.2 V vs. SHE) serving as the terminal electron acceptor. The electric current deriving from microbially-driven toluene oxidation resulted in (abiotic) hydrogen production (at a stainless-steel cathode), which sustained the reductive dechlorination of TCE to less-chlorinated intermediates (i.e., cis-DCE, VC, and ETH), at a maximum rate of 500 ÎŒeq Lâ1 dâ1, in the bulk of the reactor. A phylogenetic and functional gene-based analysis of the âbioelectric wellâ confirmed the establishment of a microbiome harboring the metabolic potential for anaerobic toluene oxidation and TCE reductive dechlorination. However, Toluene degradation and current generation were found to be rate-limited by external mass transport phenomena, thus indicating the existing potential for further process optimization
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