26 research outputs found

    Analytical approach to network inference : Investigating degree distribution

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    The authors thank Dr. Daniel Vogel for helpful comments and discussions. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 642563.Peer reviewedPublisher PD

    Iterative procedure for network inference

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    Acknowledgements This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 642563. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.Peer reviewedPostprin

    Impact of network characteristics on network reconstruction

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    When a network is inferred from data, two types of errors can occur: false positive and false negative conclusions about the presence of links. We focus on the influence of local network characteristics on the probability α\alpha - of type I false positive conclusions, and on the probability β\beta - of type II false negative conclusions, in the case of networks of coupled oscillators. We demonstrate that false conclusion probabilities are influenced by local connectivity measures such as the shortest path length and the detour degree, which can also be estimated from the inferred network when the true underlying network is not known a priory. These measures can then be used for quantification of the confidence level of link conclusions, and for improving the network reconstruction via advanced concepts of link thresholding

    Improving network inference : The impact of false positive and false negative conclusions about the presence or absence of links

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    This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 642563.Peer reviewedPostprin

    The Blurred Lines of Intercultural Mediation: Professional Recognition through Formal and Informal Practices in Italy

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    Over the past few decades, Europe has been feeding on a narrative of skepticism and crisis that has not spared the discourse on migration, highlighting states’ fragmentation over the adoption of common migration man-agement policies. Long-lasting difficulties in regional integration have been heightened and efforts to build a sound knowledge-based European society weakened. European states are meeting migration challenges and in so doing are inter alia confronted with the essential role played by intercultural mediation in the interaction between foreigners and host societies. Within such a framework, this article aims at contributing to the debate on the shortcomings of integrated mediation practices across Europe. It thus analyses the theoretical frame-work on mediation, with reference to instruments adopted by both the European Union and the Council of Europe, and accompanies such a review with reflections triggered by an empirical study on mediation conduc-ted at a local level in Italy. The country sets an interesting case study, as it faces well-known migration manage-ment issues that meet Eurosceptic and nationalist tones. The research explores the regional institutional system in place, or the absence thereof, and touches upon how this is perceived and experienced by mediation professionals operating in the asylum and reception field. It provides instances of how, despite some transna-tional coordination, those who operate at the national and local level have heterogeneous backgrounds and refer to sub-state institutional frameworks that are rather far from the idea of a regionally integrated profession-alisation of the role. Drawing thus parallels between the European and the local context, the contribution suggests the rethinking of the professional figure of the mediator and the possibility of grounding the role on common educational and training paths. Keywords: Council of Europe, European Union, Intercultural Mediation, Cultural Diversity, Migration, European Social Inclusio

    Latency correction in sparse neuronal spike trains

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    Background: In neurophysiological data, latency refers to a global shift of spikes from one spike train to the next, either caused by response onset fluctuations or by finite propagation speed. Such systematic shifts in spike timing lead to a spurious decrease in synchrony which needs to be corrected. New Method: We propose a new algorithm of multivariate latency correction suitable for sparse data for which the relevant information is not primarily in the rate but in the timing of each individual spike. The algorithm is designed to correct systematic delays while maintaining all other kinds of noisy disturbances. It consists of two steps, spike matching and distance minimization between the matched spikes using simulated annealing. Results: We show its effectiveness on simulated and real data: cortical propagation patterns recorded via calcium imaging from mice before and after stroke. Using simulations of these data we also establish criteria that can be evaluated beforehand in order to anticipate whether our algorithm is likely to yield a considerable improvement for a given dataset. Comparison with Existing Method(s): Existing methods of latency correction rely on adjusting peaks in rate profiles, an approach that is not feasible for spike trains with low firing in which the timing of individual spikes contains essential information. Conclusions: For any given dataset the criterion for applicability of the algorithm can be evaluated quickly and in case of a positive outcome the latency correction can be applied easily since the source codes of the algorithm are publicly available.Comment: 15 pages, 9 figure

    Reconstruction scheme for excitatory and inhibitory dynamics with quenched disorder: application to zebrafish imaging

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    An inverse procedure is developed and tested to recover functional and structural information from global signals of brains activity. The method assumes a leaky-integrate and fire model with excitatory and inhibitory neurons, coupled via a directed network. Neurons are endowed with a heterogenous current value, which sets their associated dynamical regime. By making use of a heterogenous mean-field approximation, the method seeks to reconstructing from global activity patterns the distribution of in-coming degrees, for both excitatory and inhibitory neurons, as well as the distribution of the assigned currents. The proposed inverse scheme is first validated against synthetic data. Then, time-lapse acquisitions of a zebrafish larva recorded with a two-photon light sheet microscope are used as an input to the reconstruction algorithm. A power law distribution of the in-coming connectivity of the excitatory neurons is found. Local degree distributions are also computed by segmenting the whole brain in sub-regions traced from annotated atlas

    Congenital aplasia of the optic chiasm and esophageal atresia: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>The complete absence of the chiasm (chiasmal aplasia) is a rare clinical condition. Hypoplasia of the optic nerve and congenital nystagmus are almost invariably associated characteristics. Microphthalmos or anophthalmos are common features in chiasmal aplasia, while central nervous system abnormalities are less frequent. Esophageal atresia can be isolated or syndromic. In syndromic cases, it is frequently associated with cardiac, limb, renal or vertebral malformations and anal atresia. More rarely, esophageal atresia can be part of anophthalmia-esophageal-genital syndrome, which comprises anophthalmia or microphthalmia, genital abnormalities, vertebral defects and cerebral malformations. Here, a previously unreported case of chiasmal aplasia presenting without microphthalmos and associated with esophageal atresia is described.</p> <p>Case presentation</p> <p>Aplasia of the optic chiasm was identified in a Caucasian Italian 8-month-old boy with esophageal atresia. An ultrasound examination carried out at 21 weeks' gestation revealed polyhydramnios. Intrauterine growth retardation, esophageal atresia and a small atrial-septal defect were subsequently detected at 28 weeks' gestation. Repair of the esophageal atresia was carried out shortly after birth. A jejunostomy was carried out at four months to facilitate enteral feeding. The child was subsequently noted to be visually inattentive and to be neurodevelopmentally delayed. Magnetic resonance imaging revealed chiasmal aplasia. No other midline brain defects were found. His karyotype was normal.</p> <p>Conclusion</p> <p>If achiasmia is a spectrum, our patient seems to depict the most severe form, since he appears to have an extremely severe visual impairment. This is in contrast to most of the cases described in the literature, where patients maintain good--or at least useful-- visual function. To the best of our knowledge, the association of optic nerve hypoplasia, complete chiasmal aplasia, esophageal atresia and atrial-septal defect, choanal atresia, hypertelorism and psychomotor retardation has never been described before.</p
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