59 research outputs found

    Searching for galaxy-scale strong-lenses in galaxy clusters with deep networks -- I: methodology and network performance

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    Galaxy-scale strong lenses in galaxy clusters provide a unique tool to investigate their inner mass distribution and the sub-halo density profiles in the low-mass regime, which can be compared with the predictions from cosmological simulations. We search for galaxy-galaxy strong-lensing systems in HST multi-band imaging of galaxy cluster cores from the CLASH and HFF programs by exploring the classification capabilities of deep learning techniques. Convolutional neural networks are trained utilising highly-realistic simulations of galaxy-scale strong lenses injected into the HST cluster fields around cluster members. To this aim, we take advantage of extensive spectroscopic information on member galaxies in 16 clusters and the accurate knowledge of the deflection fields in half of these from high-precision strong lensing models. Using observationally-based distributions, we sample magnitudes, redshifts and sizes of the background galaxy population. By placing these sources within the secondary caustics associated with cluster galaxies, we build a sample of ~3000 galaxy-galaxy strong lenses which preserve the full complexity of real multi-colour data and produce a wide diversity of strong lensing configurations. We study two deep learning networks processing a large sample of image cutouts in three HST/ACS bands, and we quantify their classification performance using several standard metrics. We find that both networks achieve a very good trade-off between purity and completeness (85%-95%), as well as good stability with fluctuations within 2%-4%. We characterise the limited number of false negatives and false positives in terms of the physical properties of the background sources and cluster members. We also demonstrate the neural networks' high degree of generalisation by applying our method to HST observations of 12 clusters with previously known galaxy-scale lensing systems.Comment: 17 pages, 13 figures, to be published on A&

    Seroprevalence of five neglected parasitic diseases among immigrants accessing five infectious and tropical diseases units in Italy: a cross-sectional study.

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    : This multicentre cross-sectional study aims to estimate the prevalence of five neglected tropical diseases (Chagas disease, filariasis, schistosomiasis, strongyloidiasis, toxocariasis) among immigrants accessing health care facilities in five Italian cities (Bologna, Brescia, Florence, Rome, Verona). : Individuals underwent a different set of serological tests, according to country of origin and presence of eosinophilia. Seropositive patients were treated and further followed up. : A total of 930 adult immigrants were enrolled: 477 men (51.3%), 445 women (47.9%), 8 transgender (0.8%); median age was 37.81 years (range 18-80). Most of them were coming from the African continent (405/930, 43.5%), the rest from East Europe, South America and Asia. A portion of 9.6% (89/930) were diagnosed with at least one of the infections under study. Seroprevalence of each specific infection varied from 3.9% (7/180) for Chagas diseases to 9.7% (11/113) for toxocariasis. Seropositive people were more likely to be 35 to 40 years-old male and to come from South East Asia, Sub-Saharan Africa or South America. : The results of our study confirm that neglected tropical diseases represent a substantial health problem among immigrants and highlight the need for addressing this emerging public health issue.<br/

    Geiparvarin Analogs. 4.1. Synthesis and Cytostatic Activity of Geiparvarin Analogs Bearing a Carbamate Moiety or a Furocoumarin Fragment on the Alkenyl Side Chain

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    none7As a continuation of previous studies on the synthesis and antitumor activity of geiparvarin analogues bearing a carbamate moiety in the alkyl side chain, a series of N-substituted [(E)- 3-(4,5-dihydro-5,5-dimethyl-4-oxo-2-furanyl)-2-butenyllcarbama(t1e5s a-f) were synthesized and tested with the objective to investigate the reason for the marked difference of cytostatic activity found between alkyl and phenyl derivatives. A series of compounds, characterized by different physicochemical properties, were designed in order to study this hypothesis. Moreover, to further investigate the modification of the alkenyl side chain, (E)- and (2)-[2-(4,5-dihydro- 5,5-dimethy1-4-oxo-2-furany1)propeny11-7~-furo[3,2-g][11benzop~an-7-o(nllea ,b) were synthesized, the latter compounds being the combination of two units, namely, the 3(2H)-furanone ring system endowed with potent alkylating properties and the furocoumarin portion which binds to DNA resulting in potential DNA-targeted alkylating agents. The compounds were tested for their cytostatic activity against proliferation of murine (L1210) and human (Molt/ 4F, CEM, or MT-4) tumor cells. The highest cytostatic activity found within both series of carbamic derivatives (15a-d,k and 15e,g-j) was associated with the highest global lipophilicity. With regard to compounds lla,b, the cytostatic activity of (Z)-furocoumarin llb might be related to a specific interaction with DNA (Le., intercalation).noneMANFREDINI S.; BARALDI P.G.; BAZZANINI R.; GUARNERI M.; SIMONI D.; BALZARINI J.; DE CLERCQ EManfredini, Stefano; Baraldi, Pier Giovanni; Bazzanini, R.; Guarneri, Mario; Simoni, Daniele; Balzarini, J.; DE CLERCQ, E

    Pyrazole related nucleosides. Synthesis and antiviral / antitumor activity of some substituted pyrazole and pyrazolo [4,3-d]1,2,3-triazin-4-one nucleosides

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    Several pyrazole and pyrazolo[4,3-d]-1,2,3-triazin-4-one ribonucleosides were prepared and tested for antiviral/antitumor activities. Appropriate heterocyclic bases were prepared by standard methodologies. Glycosylation of pyrazoles 6a-e,g,i and of pyrazolo[4,3-d]-1,2,3-triazin-4-ones 12f-1 mediated by silylation with hexamethyldisilazane, with 1-beta-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose, gave in good yields the corresponding glycosides 7a-e,g, 8g,i, 13f,h,k, and 14f, but could not be applied to compounds 12g,i,j,l. To overcome this occurrence, a different strategy involving the preparation, diazotization, and in situ cyclization of opportune pyrazole glycosides 9 and 10 was required. Moreover derivatives having the general formula 5 were considered not only as synthetic intermediates in the synthesis of 3 but also as carbon bioisosteres of ribavirin 4. All compounds were evaluated in vitro for cytostatic and antiviral activity. The pyrazolo[4,3-d]-1,2,3-triazin-4-one nucleosides that resulted were substantially devoid of any activity; only 15h,k showed a moderate cytostatic activity against T-cells. However, pyrazole nucleosides 9b,c,e were potent and selective cytotoxic agents against T-lymphocytes, whereas 9e showed a selective, although not very potent, activity against coxsackie B1

    Prodrugs of Ara-CMP and Ara-AMP with a S-acyl-2-thioethyl (SATE) biolabile phosphate protecting group: Synthesis and biological evaluation

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    The bis(S-pivaloyl-2-thioethyl) phosphotriesters of Ara-C and Ara-A were synthesized as potential bioreversible mononucleotide prodrugs. Some N- and O-acylated derivatives were also prepared with the aim to modify the lipophilicity of the title pronucleotides. Compounds were tested for their antitumor/antiviral activity against a variety of tumor cells and viruses

    Distributions of energy, luminosity, duration, and waiting times of gamma-ray burst pulses with known redshift detected by Fermi/GBM

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    Discovered more than 50 years ago, gamma-ray burst (GRB) prompt emission remains the most puzzling aspect of GRB physics. Its complex and irregular nature should reveal how newborn GRB engines release their energy. In this respect, the possibility that GRB engines could operate as self-organized critical (SOC) systems has been put forward. Here, we present the energy, luminosity, waiting time, and duration distributions of individual pulses of GRBs with known redshift detected by the Fermi Gamma-ray Burst Monitor (GBM). This is the first study of this kind in which selection effects are accounted for. The compatibility of our results with the framework of SOC theory is discussed. We found evidence for an intrinsic break in the power-law models that describe the energy and the luminosity distributions
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