316 research outputs found
Organising Equal Freedom:From antagonism to agonism
This thesis is a theoretical and empirical study of prefigurative, pluralist, radically horizontal intra and inter personal processes of subjectification. The research context is Greek radical worker co-operatives abiding to pluralist radically horizontal organizing practices and prefigurative politics (autonomous, and social and solidarity economy). My methodological, conceptual, and empirical contributions aimed to align and support this contextâs situated process for radically horizontal organizing, that is âco-formation toward synthesisâ (Gr. "syndiamorfosi pros synthesiâ) assembly organizing, and address a key situated challenge, that of informal hierarchies. Through an intersubjective interpretative phenomenological lens, I employed a Militant Research -situated, co-produced, movement-led- methodological framework. This framework also entailed developing this thesis through practices of pluralist radical horizontality. Within academic discussions on selfhood, equality, freedom, and prefiguration, I developed the sensitising concepts of agonistic self-creation for intra personal processes, and agonistic empathy for inter personal processes of pluralist radical horizontality. To support these intra and inter personal processes further, I followed a fictocritical approach to empirical data. This approach allowed me to blend fact, fiction, theory, critique, and literary methods in single narratives. I developed four such narratives. Finally, I proposed seven lenses for observing movements in intra and inter personal processes, and Heraclitusâ agonistic metaphor of the farmersâ drink kykeon for visualizing these movements
A catalogue of nuclear stellar velocity dispersions of nearby galaxies from \u2009H\u3b1 STIS spectra to constrain supermassive black hole masses
We present new measurements for the nuclear stellar velocity dispersion \u3c3* within sub-arcsecond apertures for 28 nearby galaxies. Our data consist of Space Telescope Imaging Spectrograph (STIS) long-slit spectra obtained with the G750M grating centred on the H\u3b1 spectral range. We fit the spectra using a library of single stellar population models and Gaussian emission lines, while constraining in most cases the stellar-population content from an initial fit to G430L STIS spectra. We illustrate how these \u3c3* measurements can be useful for constraining the mass M\u2022 of supermassive black holes (SBHs) by concentrating on the cases of the lenticular galaxies NGC 4435 and NGC 4459. These are characterized by similar ground-based half-light radii stellar velocity dispersion \u3c3e values but remarkably different M\u2022 as obtained from modelling their central ionized-gas kinematics, where NGC 4435 appears to host a significantly undermassive SBH compared to what is expected from the M\u2022 - \u3c3e relation. For both galaxies, we build Jeans axisymmetric dynamical models to match the ground-based stellar kinematics obtained with Spectrographic Areal Unit for Research on Optical Nebulae integral-field spectrograph, including an SBH with M\u2022 value as predicted by the M\u2022 - \u3c3e relation and using high-resolution HST images taken with the Advanced Camera for Surveys to construct the stellar-mass model. By mimicking the HST observing conditions we use such reference models to make a prediction for the nuclear \u3c3* value. Whereas this was found to agree with our nuclear \u3c3* measurement for NGC 4459, for NGC 4435 the observed \u3c3* is remarkably smaller than the predicted one, which further suggests that this galaxy could host an undermassive SBH
PLIERS: a Popularity-Based Recommender System for Content Dissemination in Online Social Networks
In this paper, we propose a novel tag-based recommender system called PLIERS,
which relies on the assumption that users are mainly interested in items and
tags with similar popularity to those they already own. PLIERS is aimed at
reaching a good tradeoff between algorithmic complexity and the level of
personalization of recommended items. To evaluate PLIERS, we performed a set of
experiments on real OSN datasets, demonstrating that it outperforms
state-of-the-art solutions in terms of personalization, relevance, and novelty
of recommendations.Comment: Published in SAC '16: Proceedings of the 31st Annual ACM Symposium on
Applied Computin
Network disruption and recovery: Co-evolution of defender and attacker in a dynamic game
The evolution of interactions between individuals or organizations are a central theme of complexity research. We aim at modeling a dynamic game on a network where an attacker and a defender compete in disrupting and reconnecting a network. The choices of how to attack and defend the network are governed by a Genetic Algorithm (GA) which is used to dynamically choose among a set of available strategies. Our analysis shows that the choice of strategy is particularly important if the resources available to the defender are slightly higher than the attackers'. The best strategies found through GAs by the attackers and defenders are based on betweenness centrality. Our results agree with previous literature assessing strategies for network attack and defense in a static context. However, our paper is one of the first ones to show how a GA approach can be applied in a dynamic game on a network. This research provides a starting-point to further explore strategies as we currently apply a limited set of strategies only
Exosome-mediated transfer of miR-222 is sufficient to increase tumor malignancy in melanoma
BACKGROUND:
Growing evidence is showing that metastatic cell populations are able to transfer their characteristics to less malignant cells. Exosomes (EXOs) are membrane vesicles of endocytic origin able to convey their cargo of mRNAs, microRNAs (miRs), proteins and lipids from donors to proximal as well as distant acceptor cells. Our previous results indicated that miR-221&222 are key factors for melanoma development and dissemination. The aim of this study was to verify whether the tumorigenic properties associated with miR-222 overexpression can be also propagated by miR-222-containing EXOs.
METHODS:
EXOs were isolated by UltraCentrifugation or Exoquick-TC(Ž) methods. Preparations of melanoma-derived vesicles were characterized by using the Nanosight⢠technology and the expression of exosome markers analyzed by western blot. The expression levels of endogenous and exosomal miRNAs were examined by real time PCR. Confocal microscopy was used to evaluate transfer and uptake of microvesicles from donor to recipient cells. The functional significance of exosomal miR-222 was estimated by analyzing the vessel-like process formation, as well as cell cycle rates, invasive and chemotactic capabilities.
RESULTS:
Besides microvesicle marker characterization, we evidenced that miR-222 exosomal expression mostly reflected its abundance in the cells of origin, correctly paralleled by repression of its target genes, such as p27Kip1, and induction of the PI3K/AKT pathway, thus confirming its functional implication in cancer. The possible differential significance of PI3K/AKT blockade was assessed by using the BKM120 inhibitor in miR-222-transduced cell lines. In addition, in vitro cultures showed that vesicles released by miR-222-overexpressing cells were able to transfer miR-222-dependent malignancy when taken-up by recipient primary melanomas. Results were confirmed by antagomiR-221&222 treatments and by functional observations after internalization of EXOs devoid of these miRs
A Transfer Learning and Explainable Solution to Detect mpox from Smartphones images
In recent months, the monkeypox (mpox) virus -- previously endemic in a
limited area of the world -- has started spreading in multiple countries until
being declared a ``public health emergency of international concern'' by the
World Health Organization. The alert was renewed in February 2023 due to a
persisting sustained incidence of the virus in several countries and worries
about possible new outbreaks. Low-income countries with inadequate
infrastructures for vaccine and testing administration are particularly at
risk.
A symptom of mpox infection is the appearance of skin rashes and eruptions,
which can drive people to seek medical advice. A technology that might help
perform a preliminary screening based on the aspect of skin lesions is the use
of Machine Learning for image classification. However, to make this technology
suitable on a large scale, it should be usable directly on mobile devices of
people, with a possible notification to a remote medical expert.
In this work, we investigate the adoption of Deep Learning to detect mpox
from skin lesion images. The proposal leverages Transfer Learning to cope with
the scarce availability of mpox image datasets. As a first step, a homogenous,
unpolluted, dataset is produced by manual selection and preprocessing of
available image data. It will also be released publicly to researchers in the
field. Then, a thorough comparison is conducted amongst several Convolutional
Neural Networks, based on a 10-fold stratified cross-validation. The best
models are then optimized through quantization for use on mobile devices;
measures of classification quality, memory footprint, and processing times
validate the feasibility of our proposal. Additionally, the use of eXplainable
AI is investigated as a suitable instrument to both technically and clinically
validate classification outcomes.Comment: Submitted to Pervasive and Mobile Computin
Automated Support for the Design and Validation of Fault Tolerant Parameterized Systems: a case study
We propose a methodology to use the infinite state model checker MCMT, based on Satisfiability Modulo Theory techniques, for assisting in the design of fault tolerant algorithms. To prove the practical viability of our methodology, we apply it to formally check the agreement property of the reliable broadcast protocols of Chandra and Toueg
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