A novel approach to the classification of terrestrial drainage networks based on deep learning and preliminary results on solar system bodies

Several approaches were proposed to describe the geomorphology of drainage networks and the abiotic/biotic factors determining their morphology. There is an intrinsic complexity of the explicit qualification of the morphological variations in response to various types of control factors and the difficulty of expressing the cause-effect links. Traditional methods of drainage network classification are based on the manual extraction of key characteristics, then applied as pattern recognition schemes. These approaches, however, have low predictive and uniform ability. We present a different approach, based on the data-driven supervised learning by images, extended also to extraterrestrial cases. With deep learning models, the extraction and classification phase is integrated within a more objective, analytical, and automatic framework. Despite the initial difficulties, due to the small number of training images available, and the similarity between the different shapes of the drainage samples, we obtained successful results, concluding that deep learning is a valid way for data exploration in geomorphology and related fields

Necrosis avascular secundaria al tratamiento de la luxación congénita de cadera: relación entre factores terapéuticos y secuelas radiológicas

Se presentan 108 casos de Luxación Congénita de Cadera (LCC) unilateral tratados con la misma metódica terapéutica: tracción más reducción abierta o cerrada dependiendo de los hallazgos artrográficos. Tras un seguimiento medio de 7 años (Rango: 5-13), 5 (5%) tenían una coxa magna, 14 (13%) mostraban disminución de la altura epifisaria, 22 (20%) tenían una coxa magna con disminución de la altura epifisaria 10 (9%) presentaban lesión fisaria residual. El análisis estadístico demostró asociación significativa (p<0,05 ) entre el desarrollo de coxa magna con disminución de la altura epifisaria y la ausencia de descenso cefálico al terminar la tracción, así como con la reducción abierta. La lesión fisaria residual, se encontró asociada significativamente a LCC Tipo IV de Tönnis, caderas que estuvieron más de 5 semanas en tracción, fallo en el descenso cefálico al finalizar la tracción y reducción abierta. En conclusión, se recomienda la tracción preoperatoria «efectiva», que desciende la cabeza femoral a nivel del cotilo, para disminuir las alteraciones radiológicas finales, secuelas de necrosis avascular.A total of 108 patients with unilateral congenital dislocation of the hip treated by the same therapeutic approach, are reviewed. The protocol for treatment consisted in traction and open or closed reduction, depending of the arthrographic findings. After 7-year follow-up (range, 5-13), 5 (5%) had coxa magna, 14 (13%) showed a decrease in epiphyseal height, 22 (20%) exhibited both coxa magna and decreased epiphyseal height, and 10 (9%) showed physeal damage. The statistical analysis revealed a significant relationship (p < 0,05) between the development of coxa magna with decreased epiphyseal height and both an absence of femoral head descent after traction and an open reduction of the hip. Physeal damage was found to be associated to Tönnis type-IV congenital dislocation, to hips undergoing more than 5 weeks traction, to failed cephalic descent following traction and an open reduction procedure. In conclusion, a effective preoperative hip traction allowing an appropriate descent of the femoral head to the acetabulum is recommended in order to prevent radiological alterations induced by avascular necrosis

The search for galaxy cluster members with deep learning of panchromatic HST imaging and extensive spectroscopy

Context. The next generation of extensive and data-intensive surveys are bound to produce a vast amount of data, which can be efficiently dealt with using machine-learning and deep-learning methods to explore possible correlations within the multi-dimensional parameter space. Aims. We explore the classification capabilities of convolution neural networks (CNNs) to identify galaxy cluster members (CLMs) by using Hubble Space Telescope (HST) images of fifteen galaxy clusters at redshift 0.19≲ z≲ 0.60, observed as part of the CLASH and Hubble Frontier Field programmes. Methods. We used extensive spectroscopic information, based on the CLASH-VLT VIMOS programme combined with MUSE observations, to define the knowledge base. We performed various tests to quantify how well CNNs can identify cluster members on ht basis of imaging information only. Furthermore, we investigated the CNN capability to predict source memberships outside the training coverage, in particular, by identifying CLMs at the faint end of the magnitude distributions. Results. We find that the CNNs achieve a purity-completeness rate ≳ 90%, demonstrating stable behaviour across the luminosity and colour of cluster galaxies, along with a remarkable generalisation capability with respect to cluster redshifts. We concluded that if extensive spectroscopic information is available as a training base, the proposed approach is a valid alternative to catalogue-based methods because it has the advantage of avoiding photometric measurements, which are particularly challenging and time-consuming in crowded cluster cores. As a byproduct, we identified 372 photometric cluster members, with mag(F814) < 25, to complete the sample of 812 spectroscopic members in four galaxy clusters RX J2248-4431, MACS J0416-2403, MACS J1206-0847 and MACS J1149+2223. Conclusions. When this technique is applied to the data that are expected to become available from forthcoming surveys, it will be an efficient tool for a variety of studies requiring CLM selection, such as galaxy number densities, luminosity functions, and lensing mass reconstruction

New high-precision strong lensing modeling of Abell 2744. Preparing for JWST observations

We present a new strong lensing (SL) model of the Hubble Frontier Fields galaxy cluster Abell 2744, at z=0.3072, by exploiting archival Hubble Space Telescope (HST) multi-band imaging and Multi Unit Spectroscopic Explorer (MUSE) follow-up spectroscopy. The lens model considers 90 spectroscopically confirmed multiple images (from 30 background sources), which represents the largest secure sample for this cluster field prior to the recently acquired James Webb Space Telescope observations. The inclusion of the sub-structures within several extended sources as model constraints allows us to accurately characterize the inner total mass distribution of the cluster and the position of the cluster critical lines. We include the lensing contribution of 225 cluster members, 202 of which are spectroscopically confirmed. We also measure the internal velocity dispersion of 85 cluster galaxies to independently estimate the role of the subhalo mass component in the lens model. We investigate the effect of the cluster environment on the total mass reconstruction of the cluster core with two different mass parameterizations. We consider the mass contribution from three external clumps, either based on previous weak-lensing studies, or extended HST imaging of luminous members around the cluster core. In the latter case, the observed positions of the multiple images are better reproduced, with a remarkable accuracy of 0.37", a factor of $\sim2$ smaller than previous lens models. We develop and make publicly available a Strong Lensing Online Tool (SLOT) to exploit the predictive power and the full statistical information of this and future models, through a simple graphical interface. We plan to apply our high-precision SL model to the first analysis of the GLASS-JWST-ERS program, specifically to measure the intrinsic physical properties of high-$z$ galaxies from robust magnification maps.Comment: 14 pages, 9 figures, 4 table

The Kormendy relation of early-type galaxies as a function of wavelength in Abell S1063, MACS J0416.1-2403 and MACS J1149.5+2223

The wavelength dependence of the Kormendy relation (KR) is well characterised at low-redshift, but poorly studied at intermediate redshifts. The KR provides information on the evolution of the population of early-type galaxies (ETGs), therefore, by studying it, we may shed light on the assembly processes of these objects and their size evolution. Since studies at different redshifts are generally conducted in different rest-frame wavebands, investigating whether there is a wavelength dependence of the KR is fundamental to interpret the conclusions we might draw from it. We analyse the KRs of the three Hubble Frontier Fields clusters, Abell S1063 (z = 0.348), MACS J0416.1-2403 (z = 0.396), and MACS J1149.5+2223 (z = 0.542), as a function of wavelength. This is the first time the KR of ETGs has been explored consistently in such a large range of wavelength at intermediate redshifts. We exploit very deep HST photometry, ranging from the observed B-band to the H-band, and VLT/MUSE integral field spectroscopy. We improve the structural parameters estimation we performed in a previous work (Tortorelli et al. 2018) by means of a newly developed Python package called morphofit (Tortorelli&Mercurio 2023). With its use on cluster ETGs, we find that the KR slopes smoothly increase with wavelength from the optical to the near-infrared bands in all three clusters, with the intercepts getting fainter at lower redshifts due to the passivisation of the ETGs population. The slope trend is consistent with previous findings at lower redshifts. The slope increase with wavelength implies that smaller size ETGs are more centrally concentrated than larger size ETGs in the near-infrared with respect to the optical regime. Since different bands probe different stellar populations in galaxies, the slope increase also implies that smaller ETGs have stronger internal gradients with respect to larger ETGs.Comment: Submitted to Astronomy and Astrophysics in the form of letter to the Editor, 5 pages, 1 figure, 1 tabl

Candidate Cluster Members with Deep learning

The next generation of extensive and data-intensive surveys are bound to produce a vast amount of data, which can be efficiently dealt with using machine-learning and deep-learning methods to explore possible correlations within the multi-dimensional parameter space. We explore the classification capabilities of convolution neural networks (CNNs) to identify galaxy cluster members (CLMs) by using Hubble Space Telescope (HST) images of fifteen galaxy clusters at redshift 0.19≲z≲0.60, observed as part of the CLASH and Hubble Frontier Field programmes. We used extensive spectroscopic information, based on the CLASH-VLT VIMOS programme combined with MUSE observations, to define the knowledge base. We performed various tests to quantify how well CNNs can identify cluster members on ht basis of imaging information only. Furthermore, we investigated the CNN capability to predict source memberships outside the training coverage, in particular, by identifying CLMs at the faint end of the magnitude distributions. We find that the CNNs achieve a purity-completeness rate ≳90%, demonstrating stable behaviour across the luminosity and colour of cluster galaxies, along with a remarkable generalisation capability with respect to cluster redshifts. We concluded that if extensive spectroscopic information is available as a training base, the proposed approach is a valid alternative to catalogue-based methods because it has the advantage of avoiding photometric measurements, which are particularly challenging and time-consuming in crowded cluster cores. As a byproduct, we identified 372 photometric cluster members, with mag(F814)<25, to complete the sample of 812 spectroscopic members in four galaxy clusters RX J2248-4431, MACS J0416-2403, MACS J1206-0847 and MACS J1149+2223. When this technique is applied to the data that are expected to become available from forthcoming surveys, it will be an efficient tool for a variety of studies requiring CLM selection, such as galaxy number densities, luminosity functions, and lensing mass reconstruction

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

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&

Astroinformatics based search for globular clusters in the Fornax Deep Survey

In the last years, Astroinformatics has become a well-defined paradigm for many fields of Astronomy. In this work, we demonstrate the potential of a multidisciplinary approach to identify globular clusters (GCs) in the Fornax cluster of galaxies taking advantage of multiband photometry produced by the VLT Survey Telescope using automatic self-adaptive methodologies. The data analysed in this work consist of deep, multiband, partially overlapping images centred on the core of the Fornax cluster. In this work, we use a Neural Gas model, a pure clustering machine learning methodology, to approach the GC detection, while a novel feature selection method (ΦLAB) is exploited to perform the parameter space analysis and optimization. We demonstrate that the use of an Astroinformatics-based methodology is able to provide GC samples that are comparable, in terms of purity and completeness with those obtained using single-band HST data and two approaches based, respectively, on a morpho-photometric and a Principal Component Analysis using the same data discussed in this work

Population genetic structure of Schistosoma haematobium and Schistosoma haematobium x Schistosoma bovis hybrids among school-aged children in Côte d'Ivoire

While population genetics of Schistosoma haematobium have been investigated in West Africa, only scant data are available from Cote d'Ivoire. The purpose of this study was to analyze both genetic variability and genetic structure among S. haematobium populations and to quantify the frequency of S. haematobium x S. bovis hybrids in school-aged children in different parts of Cote d'Ivoire. Urine samples were subjected to a filtration method and examined microscopically for Schistosoma eggs in four sites in the western and southern parts of Cote d'Ivoire. A total of 2692 miracidia were collected individually and stored on Whatman((R)) FTA cards. Of these, 2561 miracidia were successfully genotyped for species and hybrid identification using rapid diagnostic multiplex mitochondrial cox1 PCR and PCR Restriction Fragment Length Polymorphism (PCR-RFLP) analysis of the nuclear ITS2 region. From 2164 miracidia, 1966 (90.9%) were successfully genotyped using at least 10 nuclear microsatellite loci to investigate genetic diversity and population structure. Significant differences were found between sites in all genetic diversity indices and genotypic differentiation was observed between the site in the West and the three sites in the East. Analysis at the infrapopulation level revealed clustering of parasite genotypes within individual children, particularly in Duekoue (West) and Sikensi (East). Of the six possible cox1-ITS2 genetic profiles obtained from miracidia, S. bovis cox1 x S. haematobium ITS2 (42.0%) was the most commonly observed in the populations. We identified only 15 miracidia (0.7%) with an S. bovis cox1 x S. bovis ITS2 genotype. Our study provides new insights into the population genetics of S. haematobium and S. haematobium x S. bovis hybrids in humans in Cote d'Ivoire and we advocate for researching hybrid schistosomes in animals such as rodents and cattle in Cote d'Ivoire