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Indoor Air Quality monitoring using low-cost sensors: Experimental set-up and characterization procedure
No full textMonitoring indoor environmental quality is a key requirement for addressing challenges related to smart cities and human health, including indoor air quality. Traditionally, indoor air monitoring has relied on high-end instrumentation, limiting large-scale and widespread deployment. The increasing availability of low-cost sensors offers new opportunities for scalable monitoring systems, provided their metrological performance is properly characterised. In this context, the Italian PRIN project MIRABLE (Measurement Infrastructure for Research on Healthy and Zero Energy Buildings in Novel Living Lab Ecosystems), involving the Italian National Metrology Institute (INRiM) and the Politecnico di Torino, aims to develop a multidomain measurement infrastructure for indoor environments using low-cost sensors in a full-scale living laboratory. At INRiM, a dedicated calibration system was developed to ensure the metrological traceability of CO2 and CO measurements obtained from low-cost sensors. Reference gas mixtures were prepared gravimetrically according to the International Standard ISO 6142-1 and dynamically diluted to reach low concentration levels. Calibration was carried out using a primary non-dispersive infrared (NDIR) reference analyser and a specially designed calibration chamber. This study presents calibration results for selected CO2 low-cost sensors and a preliminary evaluation of measurement uncertainty. The same methodology will be extended to low-cost CO and NOx sensors in future work
Graph theoretical characterization and QSPR modeling of aluminum and magnesium hydroxide networks through integrated face degree topological indices
No full textAluminum hydroxide (gibbsite) and magnesium hydroxide (brucite) rank among the most prevalent hydroxide minerals and function as structural prototypes for diverse layered materials, including phyllosilicates, layered double hydroxides, and emerging two-dimensional halides. An exciting feature of these materials is their novel electronic and spintronic functionalities. Gibbsite adopts a dioctahedral framework with one-third of its octahedral sites vacant and stabilized by hydrogen bonding, whereas brucite forms a fully occupied trioctahedral lattice bound by van der Waals interactions. Such structural differences critically influence their stability, reactivity, and functional versatility. The present study develops a topological framework by employing classical degree-based indices, along with face degree and degree-sum variants, to characterize their network structures and compute their properties. We employ univariate and bivariate regression models in conjunction with the quantitative structure–property relationship (QSPR) approach to predict physicochemical properties of aluminum and magnesium hydroxide configurations, such as P (base 10), molecular weight, and molar refractivity. The integrated methodology demonstrates improved structural discrimination and predictive reliability, highlighting the utility of topological indices in QSPR analysis
JWST reveals extended stellar disks for ALMA-bright dusty star-forming galaxies in the Spiderweb protocluster
No full textWe present JWST/NIRCam imaging of dusty star-forming galaxies (DSFGs) detected by the Atacama Large Millimetre/submillimetre Array (ALMA) in the Spiderweb protocluster at z = 2.16. We identified 22 DSFGs detected by both ALMA and JWST, ten of which are spectroscopically confirmed as protocluster members. This is the first systematic analysis of a statistical DSFG sample in z ∼ 2 protocluster environments using JWST/NIRCam data. Most of the DSFG members exhibit red colours and reside in the dusty star-forming region of the rest-frame UVJ diagram, indicating strong dust obscuration. The Gini-M20 diagram suggests that most DSFGs in this protocluster are late-type disks, with a significant fraction displaying clumpy and disturbed rest-frame UV/optical morphologies, but few showing clear merger signatures. The DSFG members exhibit relatively large stellar disks and effective radii with a median stellar mass of log(M/M⊙) = 10.8 ± 0.3, placing them above coeval field DSFGs and typical protocluster galaxies in the size–mass relation at both rest-frame optical and near-infrared wavelengths. These sizes are comparable to those of more evolved field DSFGs at z ∼ 1 − 2, indicating accelerated structural growth in dense environments. Moreover, these DSFG members show a decreasing trend in stellar size from shorter to longer wavelengths, with a moderately steep slope comparable to coeval field DSFGs. These results may support an inside-out growth scenario for protocluster evolution, in which massive galaxies near the centre are more evolved and more strongly affected by active galactic nucleus feedback and environmental effects, for example, ram-pressure stripping. We propose that the cold gas accretion at the protocluster outskirts drives intense star formation and stellar disk growth in ALMA-detected DSFGs, which are expected to evolve into massive elliptical galaxies at later stages
PRUSSIC
No full textCharacterising the relationship between dense gas and star formation is critical for understanding the assembly of galaxies throughout cosmic history. However, due to the faintness of standard dense-gas tracers – HCN, HCO+, and HNC – dense gas in high-redshift galaxies remains largely unexplored. We present ALMA and NOEMA observations targeting HCN/HCO+/HNC (3–2) and (4–3) emission lines in 11 (mostly) gravitationally lensed dusty star-forming galaxies (DSFGs) at redshift z = 1.6 − 3.2. We detect at least one line in 10 out of 11 galaxies. Altogether, we detect 34 dense-gas transitions, more than quadrupling the number of extant high-redshift detections. Additionally, in two targets, we detect lower-abundance CO isotopologues 13CO and C18O, as well as CN emission. We derive excitation coefficients for HCN, HCO+, and HNC in DSFGs, finding them to be systematically higher than those in nearby luminous infrared galaxies. Assuming the canonical dense-mass conversion factor (αHCN = 10), we find that DSFGs have shorter dense-gas depletion times (median 23 Myr) than nearby galaxies (≈60 Myr), with a star-forming efficiency per free-fall time of 1−2%, a factor of a few higher than in local galaxies. We find a wide range of dense-gas fractions, with HCN/CO ratios ranging between 0.01 and 0.15. Finally, we put the first constraints on the redshift evolution of the cosmic dense-gas density, which increases by a factor of 7 ± 4 between z = 0 and z = 2.5, consistent with the evolution of the cosmic molecular-gas density
Diagnostic experiences of patients with cervical cancer: A qualitative study in Accra Metropolis, Ghana
No full textPurpose: The majority of cervical cancer cases are diagnosed at the advanced stage in low-income countries. However, there is limited information on the diagnostic experiences of patients with cervical cancer in sub-Saharan Africa. The current study explored the diagnostic experiences of patients who received cervical cancer diagnoses in Accra, Ghana. Method: An exploratory qualitative research design was used in this study. Using a purposive sampling technique, a semi-structured interview guide was used to interview 12 participants to gain insight into their diagnostic experiences with cervical cancer. The data collected were analysed using content analysis, in which major themes and subthemes were generated. These findings were supported with verbatim quotes from the participants. Results: Two major themes emerged with their corresponding sub-themes. 1. The patients experienced delayed diagnosis of cervical cancer. The patients attributed the delays to the missed diagnosis of the cancer in the hospital. 2. The main screening test reported was the Pap smear. Most of the patients stated they experienced pain, perceived violation of privacy during examination, and loss of blood during the Pap smear. Conclusion: It takes patients with symptoms of cervical cancer several visits to different hospitals to get a diagnosis of cervical cancer in Ghana. Initiation of traditional remedies and the perceived healthcare providers’ inability to recommend cervical cancer diagnostic tests accounted for the delayed diagnosis of the disease. These findings have implications for cervical cancer education, training of healthcare providers on cervical cancer diagnosis, and the development of cervical cancer assessment tools to improve cervical cancer management
Emulating redshift mixing due to blending in weak gravitational lensing
No full textContext. Galaxies whose images overlap in the focal plane of a telescope, commonly referred to as blends, are often located at different redshifts. Blending introduces a challenge to weak-lensing cosmology probes since such blends are subject to shear signals from multiple redshifts.
Aims. This effect can be described by joining shear bias and redshift characterisation in the effective redshift distribution, nγ(z), which includes the response of apparent shapes of detected objects to shear of galaxies at redshift, z. In this work, we propose a novel method to correct nγ(z) for redshift-mixed blending by emulating the shear response to neighbouring galaxies.
Methods. We designed a ‘half-sky-shearing’ simulation with Subaru Hyper Suprime Cam (HSC) wide-like specifications, which allowed us to extract the response of a detected object’s measured ellipticity to the shearing of neighbouring galaxies among numerous galaxy pairs.
Results. We demonstrate the feasibility of accurately emulating these pairwise responses and validate the robustness of our approach under varying observing conditions and galaxy population uncertainties. We find that the effective redshift of sources at the high-redshift tail of the distribution is about 0.05 lower than expected when the effect is not modelled.
Conclusions. Given adequately processed image simulations, our correction method can be readily incorporated into future cosmological analyses to mitigate this source of systematic error
The molecular and atomic hydrogen gas content of the Boötes Void galaxy CG 910
No full textContext. Void galaxies are located in the most under-dense environments of the Universe, where the number density of galaxies is extremely low. They are, hence, good targets for studying the secular evolution of galaxies and the slow buildup of stellar mass through star formation. Although the stellar properties of void galaxies have been studied, very little is known about their cold gas content, both molecular (H2) gas and atomic hydrogen (H
Improved Absolute Polarization Calibrator for BICEP CMB Polarimeters
No full textCosmic birefringence is a hypothesized parity violation in electromagnetism that predicts a frequency-independent polarization rotation as light propagates. This would rotate the light from the Cosmic Microwave Background, producing an unexpected EB correlation. However, cosmic birefringence angle is degenerate with instrument polarization angle, and breaking this degeneracy requires an absolute polarization calibration. We calibrate the BICEP3 telescope (a 95GHz CMB polarimeter) by observing a rotating polarized source (RPS) with both the telescope and a small test receiver called the In-Situ Absolute Angle Calibrator (ISAAC)
Comportement à long terme du revêtement de deux galeries creusées dans de l’argile peu indurée dans le laboratoire souterrain de recherche HADES (Belgique)
No full textLa démonstration de la faisabilité technique de construction de galeries dans une argile peu indurée constitue un objectif majeur du programme belge de Recherche, Développement et Démonstration (RD&D) relatif au stockage géologique des déchets radioactifs de haute activité et/ou de longue durée de vie. Ce programme s’appuie sur le laboratoire souterrain HADES, construit dans l’Argile de Boom à Mol à une profondeur de 225 mètres, en plusieurs étapes depuis les années 1980. L’étude analyse l’évolution des convergences de deux galeries construites à des périodes et selon des techniques différentes : le « Test Drift » (1987, excavation semi-manuelle) et la galerie de liaison (2002, tunnelier). Les mesures montrent que les diamètres des deux galeries continuent à évoluer et ne sont donc pas stabilisés, respectivement 37 ans (pour le « Test Drift ») et 22 ans (pour la galerie de liaison) après leur construction. Leurs modes de déformation diffèrent significativement : le « Test Drift » subit une compression dans toutes les directions tandis que la galerie de liaison présente une compression verticale associée à une extension horizontale. L’évolution des convergences du « Test Drift » est analysée via l’introduction d’un modèle viscoélastique du type Kelvin-Voigt. Son application aux mesures de convergences de cette galerie a permis de reproduire les observations in situ sur plusieurs décennies, confirmant la nécessité de développer un modèle intégrant l’évolution temporelle des différents matériaux présents et de leurs interactions afin de bien comprendre le comportement à long terme du revêtement de galeries creusées dans une argile peu indurée. Les résultats de cette étude présentent un intérêt majeur pour la conception et l’optimisation des galeries de stockage géologique en milieu argileux peu induré
Cultural inheritance through Swarm intelligence learning
No full textCultural inheritance is the main factor for the evolution and skills development through generations.
This paper exploits two Machine Learning techniques to imitate the learning process that constitutes the cultural inheritance of Elephants in a Swarm Intelligence (SI) algorithm called the Robotic-Elephant Herding Optimization (REHO). The first REHO-based learning utilizes a GPU k-Nearest Neighbors (GPU-kNN) algorithm, while the second is based on a Deep Neural Network. The performances of the Machine Learning (ML) algorithms are evaluated through five well-known metrics. Their effectiveness in solving the Target Detection Problem is compared with the original REHO via several experiments. The results show that the Deep Learning (DL) model performs better than the GPU-kNN method. These findings prompted us to propose a new hybrid SI and DL model algorithm, namely Robotic-Elephant and Particle Cultural Algorithm (REPCA). This novel approach combines the strength of the REHO-based learning model with the dynamic velocity accelerator of Particle Swarm Optimization (PSO) and knowledge inheritance provided by the Cultural Algorithm. The application problem consists of a swarm of robots that cooperate to detect an exponentially increasing number of targets, known as the Dynamic Target Detection Problem (DTDP). The proposed REPCA is compared with up-to-date algorithms on recent and real-world applications covering the robotics field and the Covid-19 pandemic. The results show a significant positive impact that the cultural inheritance and hybrid methods bring to solve the DTDP