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We investigate the viability of primordial black hole (PBH) formation in the standard model (SM) in a scenario that does not rely on specific inflationary features or any exotic physics such as phase transitions or nonminimal coupling to gravity. If the Brout-Englert-Higgs (BEH) field lies exactly at the transition between metastability and stability, its potential exhibits an inflexion point due to radiative corrections. The BEH can act like a stochastic curvaton field, leading to a non-Gaussian tail of large curvature fluctuations that later collapse into PBHs when they reenter inside the horizon. This scenario would require a precise value of the top-quark mass to ensure the Higgs stability, which is disfavored but still consistent with the most recent measurements. However, we also find that large curvature fluctuations are also generated on cosmological scales that are inconsistent with cosmic microwave background observations. We therefore conclude that the SM cannot have led to the formation of PBHs based on this mechanism. Nevertheless, a variation of the scenario based on the Palatini formulation of gravity may have provided the conditions to produce stellar-mass PBHs with an abundance comparable to dark matter, without producing too large curvature fluctuations on cosmological scales., SCOPUS: ar.j, info:eu-repo/semantics/published

Meteorites are rocks that fell from space. These unique extraterrestrial samples on Earth provide crucial information for understanding the origin and evolution of our Solar System. Antarctica is the world’s most prolific site for collecting meteorites, with more than 60% of all ∼ 80,000 meteorites ever found on Earth being collected there. Antarctic meteorites are found in areas where ice is exposed, in contrast to most of the continent’s surface which is covered by snow. During Antarctic meteorite recovery missions, these typically dark meteorites are easily found while lying on the surface of the visually contrasting light-blue colored ice. Moreover, the number of meteorites in these blue ice areas can be anomalously high. This concentration of meteorites is related to the sublimation of ice layers and the flow of the ice. Meteorite finds from Antarctica were always fairly dependent on serendipity, with experts selecting sites to visit based on their experience and a limited amount of imagery and maps. In this thesis, I perform continent wide data-driven analyses to understand the potential of blue ice areas for the recovery of meteorites and project their persistence in a warming climate. The search for Antarctic meteorites can be approached with data as there is wealth of observations available from the Antarctic continent, including meteorite finds and satellite products. Moreover, techniques to analyze large amounts of data efficiently are rapidly evolving, of which machine learning the most prominent. Hence, by combining diverse satellite observations in a deep learning framework, I detected blue ice areas. Meteorites are found on blue ice, but not all blue ice areas act as meteorite trap. Therefore, I selected indirect observations of the meteorite concentrating mechanism to understand and predict the presence of meteorites. One of these observations entailed the surface temperature. Consequently, I used projections of future surface temperatures to estimat, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

The objective of this research is to evaluate Landsat OLI/TIRS multi-spectral images, and fusion of GRASS GIS, GMT and QGIS software for land cover mapping in Guinea, West Africa. The scenes of Landsat imagery were acquired on February 2014, 2018 and 2023. Land cover data were used from FAO for validation of classes. The images were classified into 18 classes and upscaled to 10 classes for generalisation towards the study area regional setting. The method included K-means clustering using scripting approach with programming codes included in Appendix. The results demonstrated that the script-based computer vision approach to image processing, classification and analysis is effective in extracting land cover classes for environmental mapping of tropical region of West Africa., info:eu-repo/semantics/published

Mapping coastal regions is important for environmental assessment and for monitoring spatio-temporal changes. Although traditional cartographic methods using a geographic information system (GIS) are applicable in image classification, machine learning (ML) methods present more advantageous solutions for pattern-finding tasks such as the automated detection of landscape patches in heterogeneous landscapes. This study aimed to discriminate landscape patterns along the eastern coasts of Mozambique using the ML modules of a Geographic Resources Analysis Support System (GRASS) GIS. The random forest (RF) algorithm of the module 'r.learn.train' was used to map the coastal landscapes of the eastern shoreline of the Bight of Sofala, using remote sensing (RS) data at multiple temporal scales. The dataset included Landsat 8-9 OLI/TIRS imagery collected in the dry period during 2015, 2018, and 2023, which enabled the evaluation of temporal dynamics. The supervised classification of RS rasters was supported by the Scikit-Learn ML package of Python embedded in the GRASS GIS. The Bight of Sofala is characterized by diverse marine ecosystems dominated by swamp wetlands and mangrove forests located in the mixed saline-fresh waters along the eastern coast of Mozambique. This paper demonstrates the advantages of using ML for RS data classification in the environmental monitoring of coastal areas. The integration of Earth Observation data, processed using a decision tree classifier by ML methods and land cover characteristics enabled the detection of recent changes in the coastal ecosystem of Mozambique, East Africa., info:eu-repo/semantics/published

This paper presents an R-based approach to mapping dynamics of the flooded areas in the Inner Niger Delta (IND), Mali, using time series analysis of Landsat 8-9 satellite images. As the largest inland wetland in West Africa, the habitats of IND offers high potential for biodiversity of the flood-dependent e c o systems. IND is one of the most productive areas in West Africa. Mapping flooded areas based on satellite images enables to provide strategies for land management and rice planting and modelling vegetation types of IND. Our approach is based on using libraries of R programming language for processing six Landsat images, and each image was taken on November from 2013 to 2022. By capturing spatial and temporal structures of the satellite images on 2013, 2015, 2018, 2020, 2021 and 2022, the remote sensing data are combined to yield estimates of landscape dynamics that is temporally coherent, while helping to analyse fluctuations of spatial extent in fluvial wetlands caused by the hydrological processes of seasonal flooding. Further, by allowing packages of R to support image processing, an approach to mapping vegetation by NDVI, SAVI and EVI indices and visualising changes in distribution of different land cover classes over time is realised. In this context, processing Earth observation data by advanced scripting tools of R language provides new insights into complex interlace of climate-hydrological processes and vegetation responses. Our study contributes to the sustainable management of natural resources and improving knowledge on the functioning of IND ecosystems in Mali, West Africa., SCOPUS: ar.j, SCOPUS: re.j, info:eu-repo/semantics/published

[English version]This PhD thesis focuses on the comprehensive chemical and isotopic characterization of various meteorite types, aiming to enhance our understanding of significant processes that shaped the early solar system and its current state. The study centers on the volatility-controlled evaporation and condensation of elements related to asteroid impacts, specifically investigating isotopes of the moderately volatile elements (MVE) zinc, gallium, copper, and iron. The first part of this project was dedicated to the development of a Ga purification technique for precise isotopes measurements. Once established, this method was applied to meteorite samples. Most meteorites are generally regarded as pristine objects, but this is not always the case. Some processes such as thermal metamorphism, aqueous alteration and or impact-shock can significantly alter the chemical and isotopic composition of a meteorite. To investigate this, we studied the bulk MVE isotopes compositions of metal-rich equilibrated ordinary chondrites (H6). We found that the isotope systems show a correlation between the absolute range of isotopes compositions and the 50 % condensation temperature, with the more volatile elements present a higher range of fractionation. Also the range of fractionation observed does not appear to be linked to the shock stages or weathering grades of the samples indicating other processes at play. Their compositions could be inherited from the early solar nebula and accretion processes of the ordinary chondrites parent bodies, with minor effects of thermal metamorphism. We then shifted to metal-rich carbonaceous chondrites (CB and CH) which are thought to have origins related to an impact-vapor plume. We investigated their bulk elemental compositions and their isotopes compositions in Zn, Ga, Cu, and Fe. The observed distinctions in isotopic levels, particularly in Ga, Cu, Fe, and Zn, suggest complex processes at play during their formation. We could confirm vari, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

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Understanding the formation of tropical yellow to red earth (TYRE) is essential for preserving soil multifunctionality in well-drained tropical landscapes. Weathering and bioturbation mutually interact in TYRE evolution, whereas allochthonous materials appear restricted to distinct (paleo)landscapes. A layered appearance of TYRE can result from quasi-constant deposition of invertebrate mound debris, outcompeting diffusional mixing. Age-depth profiles from optically stimulated luminescence (OSL) and charcoal radiocarbon (14Cchar) data of TYRE sites in different tropical landscapes, both from the literature and the present study, all reveal quasi-constant soil upbuilding, in accordance with our model. The rates of soil upbuilding are mostly in the range of 100–200 mm*ka−1, which conforms with published mounding rates of termites and ants. By comparison, geochemical transformation of rock to saprolite proceeds at rates at least one order of magnitude smaller. Termites mining saprolite, sometimes even below indurated subsoil, produce TYRE, thus linking the interconnected subsystems of differing process rates. The work of the bioengineers appears essential for transforming the deep-weathering products into well-structured TYRE. Future research may extend the provided database, the spatial scale, and the use of geochronology, coupled with paleoenvironmental proxies, in order to further enhance our understanding of tropical soil and landscape evolution, as one basis for advances in sustainable land use., SCOPUS: re.j, info:eu-repo/semantics/published

Extreme enhancements in the total columns of carbon monoxide (CO), peroxyacetyl nitrate (PAN), ethylene (C2H4 ), methanol (CH3 OH), and formic acid (HCOOH) were observed over the Canadian high Arctic during the period of 17–22 August 2017 by a ground‐based Fourier transform infrared (FTIR) spectrometer at Eureka, Nunavut (80.05°N, 86.42°W), and by the Infrared Atmospheric Sounding Interferometer (IASI) satellite instruments. These enhancements have been attributed to wildfires in British Columbia (BC) and the Northwest Territories (NWT) of Canada, and represent the largest short‐term perturbations of PAN, C2H4, and HCOOH above ambient concentrations over the 14‐year (2006–2020) Eureka time‐series. Enhancement ratios, emission ratios, and emission factors relative to CO were calculated for all species for both FTIR and IASI observations. The C2H4 and HCOOH emission factors are significantly larger than previous studies, suggesting unusually high emissions from these fires. The wildfire plumes were also simulated using the GEOS‐Chem model. Initial GEOS‐Chem simulations displayed a severe under‐estimation relative to observations for these fire plumes resulting from the injection height scheme of the model. Sensitivity tests highlighted that injection heights of 12.5 km for BC (based on previous studies) and 10 km for the NWT fires yielded the strongest correlations with ground‐based measurements. Applying these injection heights to the model significantly improves the simulated plume transport and agreement with ground‐ and space‐based observations. GEOS‐Chem was also used to estimate the magnitude of secondary in‐plume production of CH3OH and HCOOH; it was found to be an important component (∼18%) of the enhanced HCOOH columns at Eureka., SCOPUS: ar.j, info:eu-repo/semantics/published

Large releases of volatile organic compounds (VOCs) to the atmosphere occur frequently from heavy industries and megacities but these emission fluxes are still poorly constrained in current inventories. Identifying and monitoring such localized sources is therefore key to mitigate air pollution. Using the multi-annual and spatially dense measurements from the Infrared Atmospheric Sounding Interferometer (IASI) on Metop satellites, in combination with an advanced oversampling technique that augments the spatial resolution of averaged satellite data, we explore the potential of spaceborne infrared observations for tracking down anthropogenic emitters of VOCs. We report the detection of worldwide point-sources of several major VOCs, among which ethylene (C2H4) and methanol (CH3OH). Those are found to be mainly associated with heavy industries such as petrochemical hubs, coal-related activities (e.g. coal mining and processing), and megacities. For some point-sources, we provide a first order estimate of their annual VOC emissions based on the IASI measurements. We find an important mismatch between the top-down industrial fluxes and the VOC emissions from the anthropogenic inventory EDGAR, often dominated by non-industrial sectors. This work highlights the importance of current and future infrared satellite measurements to monitor and track industrial air pollution., info:eu-repo/semantics/nonPublished

Nitrous acid (HONO) plays a key role in atmospheric chemistry as a major source – through rapid photolysis – of the hydroxyl radical (OH), the primary oxidant in the Earth's atmosphere. However, significant uncertainties remain on the spatial and temporal variability of HONO, on its formation pathways in the atmosphere, and on the contribution of its primary emissions over its secondary formation. Recently, spaceborne measurements in the UV-Vis spectral domain, taken in the early afternoon with the S5P/TROPOMI instrument, have provided a first global picture of HONO in fresh biomass burning plumes, demonstrating the importance of satellite data for improving our representation of atmospheric HONO. With daily overpass times in the early morning and early evening, the polar-orbiting IASI/Metop instruments and their global measurements of the Earth's radiance in the thermal infrared, have the potential to contribute to tackling remaining uncertainties on HONO and to complement the TROPOMI measurements.So far detected by infrared satellite sounders in the exceptional 2009 and 2019/2020 Australian bushfires only, we use a sensitive detection method to demonstrate that unambiguous HONO enhancements can also be identified in IASI spectra recorded in concentrated fire plumesworldwide. With this method, we analyse the long, unique observational timeseries (2007-2022) of IASI and we report a 15-year record of fire events in which HONO has been detected. This dataset reveals first that HONO is primarily captured by IASI at the Northern Hemisphere mid and high latitudes, and secondly that the IASI evening measurements allow a significantly higher number of HONO detections than during daytime despite the overall weaker thermal contrast and lower measurement sensitivity affecting such night-time observations. We discuss different factors that can explain these features, such as the sharp intra-day variability of HONO, the links with the diurnal variations and intensity of fires, info:eu-repo/semantics/nonPublished

Since the 1900s, emissions of CFCs and other long-lived halogenated species have profoundly affected the chemical and radiative equilibrium of our atmosphere. These halogenated compounds are known to be powerful greenhouse gases and contribute, for chlorinated and brominated compounds, to the depletion of the ozone layer and to the development of the ozone hole. With the aim of mitigating their deleterious impact on the environment, most long-lived halogenated species are controlled by international treaties, the most famous of which is the Montreal Protocol of 1987. Their monitoring is essential to evaluate the effectiveness of international regulations with regard to emissions, and ultimately to assess the environmental impacts of the changes at play. Sustained global networks located on ground have provided highly accurate measurements of the atmospheric concentrations of long-lived halogenated species for 50 years. The aim of this thesis is to assess the potential of infrared satellite sounders operating in the nadir geometry, to contribute to their monitoring and thereby complement existing surface measurement networks. The research work is centered on the exploitation of the measurements from the IASI sounder. Its stability and the consistency between the diff erent instruments on the successive Metop (A,B and C) is remarkable and makes it a reference for climate monitoring. Among other things, IASI offers the potential to investigate trends in the concentration of various species better than with any other previous or current hyperspectral infrared sounder. The low noise of IASI radiances is also such that even weakly absorbing atmospheric constituents can be tracked, on single or at least on averaged spectra. As a first step, we sought to determine which long-lived halogenated species can be detected in IASI spectra. To achieve this, we have developed an innovative methodology, based on spectral whitening, which allows to isolate the weak spectral signatures, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

Lake Chad, situated in the semi-arid region of African Sahel, plays a vital role in hydrogeological balance of regional ecosystems. It presents an essential water source and provides a habitat for rare wildlife species including migrating waterbirds. However, the lake has shrunk significantly since the 1960s and has continued to reduce in size and extent during recent decades. Trends in drying and shrinking of Lake Chad are caused by environmental factors and changed climate. The desiccation of the lake is threatening environmental sustainability. This study focused on identification of changes in the Chad Lake area, wetland extent, and associated land cover types. The methods include the Geographic Resources Analysis Support System (GRASS) Geographic Information System (GIS) for remote sensing data classification. The maximum likelihood discriminant analysis classifier was applied for analysis of multispectral Landsat 8–9 OLI/TIRS images in 2013, 2017, and 2022. Detected changes in land cover types reflect variations in water balance and wetland area and extent around Lake Chad over recent decades. Cartographic scripting tools of GRASS GIS provide an efficient method of digital image processing for monitoring endorheic lakes of Central Africa. GRASS GIS methods provide an opportunity to automatically classify Earth observation data with cartographic scripts for environmental monitoring., Der Tschadsee liegt in der halbtrockenen Region der afrikanischen Sahelzone und spielt eine entscheidende Rolle für das hydrogeolo- gische Gleichgewicht regionaler Ökosysteme. Es stellt eine wichtige Wasserquelle dar und bietet Lebensraum für seltene Wildtierarten, darunter auch wandernde Wasservögel. Allerdings ist der See seit den 1960er-Jahren erheblich geschrumpft und hat in den letzten Jahr- zehnten immer weiter an Größe und Ausdehnung abgenommen. Tendenzen zur Austrocknung und Schrumpfung des Tschadsees werden durch Umweltfaktoren und verändertes Klima verursacht. Die Austrocknung des Sees gefährdet die ökologische Nachhaltigkeit. Diese Studie konzentrierte sich auf die Identifizierung von Veränderungen im Gebiet des Tschadsees, der Feuchtgebietsausdehnung und den damit verbundenen Landbedeckungstypen. Zu den Methoden gehört das GRASS GIS zur Klassifizierung von Fernerkundungsdaten. Der Maximum-Likelihood-Diskriminanzanalyse-Klassifikator wurde für die Analyse multispektraler Landsat 8-9 OLI/TIRS-Bilder in den Jahren 2013, 2017 und 2022 angewendet. Die festgestellten Veränderungen in den Landbedeckungstypen spiegeln Schwankungen im Wasserhaushalt, in der Feuchtgebietsfläche und in der Ausdehnung rund um den Tschadsee in den letzten Jahrzehnten wider. Kartogra- fische Skriptwerkzeuge des GRASS GIS bieten eine effiziente Methode der digitalen Bildverarbeitung zur Überwachung endorheischer Seen in Zentralafrika. Die GRASS GIS-Methoden bieten die Möglichkeit, die Erdbeobachtungsdaten automatisch nutzend kartografi- schen Skripten für die Umweltüberwachung zu klassifizieren., SCOPUS: ar.j, info:eu-repo/semantics/published

In this paper, the climate and environmental datasets were processed by the scripts of Generic Mapping Tools (GMT) and R to evaluate changes in climate parameters, vegetation patters and land cover types in Burkina Faso. Located in the southern Sahel zone, Burkina Faso experiences one of the most extreme climatic hazards in sub-saharan Africa varying from the extreme floods in Volta River Basin, to desertification and recurrent droughts. The data include the TerraClimate dataset and satellite images Landsat 8-9 Operational Land Imager (OLI) and Thermal Infrared (TIRS) C2 L1. The dynamics of target climate characteristics of Burkina Faso was visualised for 2013-2022 using remote sensing data. To evaluate the environmental dynamics the TerraClimate data were used for visualizing key climate parameter: extreme temperatures, precipitation, soil moisture, downward surface shortwave radiation, vapour pressure deficit and anomaly. The Palmer Drought Severity Index (PDSI) was modelled over the study area to estimate soil water balance related to the soil moisture conditions as a prerequisites for vegetation growth. The land cover types were mapped using the k-means clustering by R. Two vegetation indices were computed to evaluate the changes in vegetation patterns over recent decade. These included the Normalized Difference Vegetation Index (NDVI) and the Soil-Adjusted Vegetation Index (SAVI) The scripts used for cartographic workflow are presented and discussed. This study contributes to the environmental mapping of Burkina Faso with aim to highlight the links between the climate processes and vegetation dynamics in West Africa., info:eu-repo/semantics/published

This study documents the changes in the Land Use/Land Cover (LULC) in the region of saline lakes in north Tunisia, Sahara Desert. Remote sensing data are a valuable data source in monitoring LULC in lacustrine landscapes, because variations in the extent of lakes are visible from space and can be detected on the images. In this study, changes in LULC of the salt pans of Tunisia were evaluated using a series of 12 Landsat 8-9 Operational Land Imager (OLI) and Thermal Infrared (TIRS) images. The images were processed with the Geographic Resources Analysis Support System (GRASS) Geographic Information System (GIS) software. The study area included four salt lakes of north Tunisia in the two regions of the Gulf of Hammamet and Gulf of Gabès: (1) Sebkhet de Sidi el Hani (Sousse Governorate), (2) Sebkha de Moknine (Mahdia Governorate), (3) Sebkhet El Rharra and (4) Sebkhet en Noual (Sfax). A quantitative estimate of the areal extent analysed in this study is 182 km × 185 km for each Landsat scene in two study areas: Gulf of Hammamet and Gulf of Gabès. The images were analysed for the period 2017–2023 on months February, April and July for each year. Spatio-temporal changes in LULC and their climate–environmental driving forces were analysed. The results were interpreted and the highest changes were detected by accuracy assessment, computing the class separability matrices, evaluating the means and standard deviation for each band and plotting the reject probability maps. Multi-temporal changes in LULC classes are reported for each image. The results demonstrated that changes in salt lakes were determined for winter/spring/summer months as detected changes in water/land/salt/sand/vegetation areas. The accuracy of the classified images was evaluated using pixel rejection probability values, which were filtered out using the ‘r.mapcalc’ module of GRASS GIS. The confidence levels were computed and visualised with a series of maps along with the error matrix and measured conve, SCOPUS: ar.j, info:eu-repo/semantics/published

Visual sunspot observations are at the base of the single longest scientific record ofsolar activity, spanning four centuries (Owens, 2013). This primary reference index, theSunspot Number, was submitted to a full revision and re-calibration (Clette et al. 2016). Anew, improved series was released in July 2015, shedding new light on our understanding ofthe long-term variations and instabilities of the 11-year solar cycle. However, uncertaintiesremain in the revised series, and errors in past historical data must be further determined.A good overview of this ongoing effort can be found in Clette et al. 2016, 2023. Thecurrent revival of long-term solar studies aims to improve our ability to predict the futureevolution of the solar cycle, a primary quest in solar physics, constrain the latest physicalmodels of the solar dynamo, and improve our understanding of the solar influence on theEarth’s climate.The purpose of this thesis is to exploit all available historical sunspot data, including thefull database of raw sunspot counts maintained by the World Data Center SILSO (https://www.sidc.be/SILSO/home), which contains more than 500.000 observations spanningseveral centuries, to derive a better understanding of the scale differences between pastobservers, starting from the beginning of modern data produced by our worldwide SILSOobserving network, going back in time. Indeed, a key issue when building such a longterm record is to bring all observations to the same normalization scale by diagnosingand compensating for various inhomogeneity factors (instrumentation, observing practices,etc.). The level of solar activity can then be compared on a constant scale across multiplecenturies back to 1610 (the invention of the telescope).An in-depth statistical study of the most recent part of the data (35 years, 280 stationssince 1981) was realized through the VAL-U-SUN project that ended in 2021 (Brain. befederal funding; https://www.sidc.be/valusun/). This thesis extends these in, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

This paper presents the object detection algorithms GRASS GIS applied for Landsat 8-9 OLI/TIRS data. The study area includes the Sudd wetlands located in South Sudan. This study describes a programming method for the automated processing of satellite images for environmental analytics, applying the scripting algorithms of GRASS GIS. This study documents how the land cover changed and developed over time in South Sudan with varying climate and environmental settings, indicating the variations in landscape patterns. A set of modules was used to process satellite images by scripting language. It streamlines the geospatial processing tasks. The functionality of the modules of GRASS GIS to image processing is called within scripts as subprocesses which automate operations. The cutting-edge tools of GRASS GIS present a cost-effective solution to remote sensing data modelling and analysis. This is based on the discrimination of the spectral reflectance of pixels on the raster scenes. Scripting algorithms of remote sensing data processing based on the GRASS GIS syntax are run from the terminal, enabling to pass commands to the module. This ensures the automation and high speed of image processing. The algorithm challenge is that landscape patterns differ substantially, and there are nonlinear dynamics in land cover types due to environmental factors and climate effects. Time series analysis of several multispectral images demonstrated changes in land cover types over the study area of the Sudd, South Sudan affected by environmental degradation of landscapes. The map is generated for each Landsat image from 2015 to 2023 using 481 maximum-likelihood discriminant analysis approaches of classification. The methodology includes image segmentation by ‘i.segment’ module, image clustering and classification by ‘i.cluster’ and ‘i.maxlike’ modules, accuracy assessment by ‘r.kappa’ module, and computing NDVI and cartographic mapping implemented using GRASS GIS. The benefits of object, info:eu-repo/semantics/published

The volcanic Kerguelen Islands are formed on one of the world’s largest submarine plateaus. Located in the remote segment of the southern Indian Ocean close to Antarctica, the Kerguelen Plateau is notable for a complex tectonic origin and geologic formation related to the Cretaceous history of the continents. This is reflected in the varying age of the oceanic crust adjacent to the plateau and the highly heterogeneous bathymetry of the Kerguelen Plateau, with seafloor structure differing for the southern and northern segments. Remote sensing data derived from marine gravity and satellite radar altimetry surveys serve as an important source of information for mapping complex seafloor features. This study incorporates geospatial information from NOAA, EMAG2, WDMAM, ETOPO1, and EGM96 datasets to refine the extent and distribution of the extracted seafloor features. The cartographic joint analysis of topography, magnetic anomalies, tectonic and gravity grids is based on the integrated mapping performed using the Generic Mapping Tools (GMT) programming suite. Mapping of the submerged features (Broken Ridge, Crozet Islands, seafloor fabric, orientation, and frequency of magnetic anomalies) enables analysis of their correspondence with free-air gravity and magnetic anomalies, geodynamic setting, and seabed structure in the southwest Indian Ocean. The results show that integrating the datasets using advanced cartographic scripting language improves identification and visualization of the seabed objects. The results include 11 new maps of the region covering the Kerguelen Plateau and southwest Indian Ocean. This study contributes to increasing the knowledge of the seafloor structure in the French Southern and Antarctic Lands., info:eu-repo/semantics/published

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Monitoring wetlands of Kenya is critical for analysis of environmental changes since they present unique ecosystems with special hydrological balance and biodiversity. In this study, the Landsat 8-9 OLI/TIRS satellite images for 2015-2022 were classified using GRASS GIS scripts to evaluate changes in the Lorian Swamp wetland, north-eastern Kenya. The results of the image analysis presented maps of land cover changes including wetlands. The study demonstrated technical effectiveness of the GRASS GIS for image analysis, and contributed to the environmental monitoring of African wetlands., La surveillance des zones humides du Kenya est essentielle pour l’analyse des changements environnementaux car elles présentent des écosystèmes uniques avec un équilibre hydrologique et une biodiversité particuliers. Dans cette étude, les images satellite Landsat 8-9 OLI/TIRS pour 2015-2022 ont été classées à l’aide de scripts SIG GRASS pour évaluer les changements dans la zone humide du marais de Lorian, au nord-est du Kenya. Les résultats de l’analyse d’images ont présenté des cartes des changements d’occupation du sol, y compris les zones humides. L’étude a démontré l’efficacité technique du SIG GRASS pour l’analyse d’images et a contribué à la surveillance environnementale en Afrique., Monitorizarea zonelor umede din Kenya este esențială pentru analiza schimbărilor de mediu, deoarece acestea prezintă ecosisteme unice cu echilibru hidrologic și biodiversitate deosebite. În acest studiu, imaginile satelitului Landsat 8-9 OLI/TIRS pentru 2015-2022 au fost clasificate folosind scripturile GRASS GIS pentru a evalua schimbările din zona umedă Lorian Swamp, din nord-estul Keniei. Rezultatele analizei imaginii au prezentat hărți ale modificărilor acoperirii solului, inclusiv zonele umede. Studiul a demonstrat eficacitatea GIS GRASS pentru monitorizarea mediului în zonele umede africane., WoS: ar.j, info:eu-repo/semantics/published

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Automated classification of satellite images is a challenging task that enables the use of remote sensing data for environmental modeling of Earth’s landscapes. In this document, we implement a GRASS GIS-based framework for discriminating land cover types to identify changes in the endorheic basins of the ephemeral salt lakes Chott Melrhir and Chott Merouane, Algeria; we employ embedded algorithms for image processing. This study presents a dataset of the nine Landsat 8–9 OLI/TIRS satellite images obtained from the USGS for a 9-year period, from 2014 to 2022. The images were analyzed to detect changes in water levels in ephemeral lakes that experience temporal fluctuations; these lakes are dry most of the time and are fed with water during rainy periods. The unsupervised classification of images was performed using GRASS GIS algorithms through several modules: ‘i.cluster’ was used to generate image classes; ‘i.maxlik’ was used for classification using the maximal likelihood discriminant analysis, and auxiliary modules, such as ‘i.group’, ‘r.support’, ‘r.import’, etc. were used. This document includes technical descriptions of the scripts used for image processing with detailed comments on the functionalities of the GRASS GIS modules. The results include the identified variations in the ephemeral salt lakes within the Algerian part of the Sahara over a 9-year period (2014–2022), using a time series of Landsat OLI/TIRS multispectral images that were classified using GRASS GIS. The main strengths of the GRASS GIS framework are the high speed, accuracy, and effectiveness of the programming codes for image processing in environmental monitoring. The presented GitHub repository, which contains scripts used for the satellite image analysis, serves as a reference for the interpretation of remote sensing data for the environmental monitoring of arid and semi-arid areas of Africa., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

This study presents new maps of the topographic and geophysical setting and seismicity in the region of the Gulf of Panama. The spatial analysis is based on the comparative analysis of the datasets on geoid, free-air gravity anomaly, topography and earthquakes. The cartographic framework is developed using the Generic Mapping Tools (GMT) scripting toolset. Seismic activity in the Central America is high due to the complex geologic setting, tectonic activity and lithosphere plate subduction. The data include the Earth Gravitational Model (EGM2008), the General Bathymetric Chart of the Oceans (GEBCO) and gravity grids. The seismicity data were collected from the Incorporated Research Institutions for Seismology (IRIS) catalogue on 1970-2021. The variations in data were compared to analyse correlations between the geophysical, seismic and topographic parameters. Free-air gravity, geoid and topographic data derived from the high-resolution datasets were used to investigate their effects on the main seismic sources in the region. The comparison of the maps showed that the distribution of the shallow earthquakes in the Pacific segment of Panama coincides with negative free-air anomalies and lower geoid values. The results revealed high values of geoid in the high mountainous regions of Panama (Cordilliera de Talamanca, southern coast of Peninsula de Azuero and eastern Panama, 77.5-78.5°W), which correspond to the topographic roughness in the highlands. Negative values of geoid are found over the Caribbean Sea basin (−4 to 0 m). The analyses of seismicity showed 1740 earthquake events varying by magnitudes from 2.9 to 7.8 at the depths up to 225 m (near the west coast of Colombia). A high concentration of the earthquakes is in the western region of the Panama's shelf waters (~82-83.5°W), and on the border with Colombia (~77-78.5°W). High gravity anomalies (over 220 mGal) are found in the mountainous regions which match the geodynamic processes associated with the Earth str, SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

We use 47 gravitational wave sources from the Third LIGO-Virgo-Kamioka Gravitational Wave Detector Gravitational Wave Transient Catalog (GWTC-3) to estimate the Hubble parameter H(z), including its current value, the Hubble constant H0. Each gravitational wave (GW) signal provides the luminosity distance to the source, and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and H(z). The source mass distribution displays a peak around 34Me, followed by a drop-off. Assuming this mass scale does not evolve with the redshift results in a H(z) measurement, yielding H0 = 68+12-8 km s-1 Mpc-1 (68% credible interval) when combined with the H0 measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the H0 estimate from GWTC-1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value of H0 = 68+8-6 km s-1 Mpc-1 with the galaxy catalog method, an improvement of 42% with respect to our GWTC-1 result and 20% with respect to recent H0 studies using GWTC-2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about H0) is the well-localized event GW190814., 0, info:eu-repo/semantics/published

The gravitational wave detector Advanced Virgo+ is currently in the commissioning phase in view of the fourth Observing Run (O4). The major upgrades with respect to the Advanced Virgo configuration are the implementation of an additional recycling cavity, the Signal Recycling cavity (SRC), at the output of the interferometer to broaden the sensitivity band and the Frequency Dependent Squeezing (FDS) to reduce quantum noise at all frequencies. The main difference of the Advanced Virgo + detector with respect to the LIGO detectors is the presence of marginally stable recycling cavities, with respect to the stable recycling cavities present in the LIGO detectors, which increases the difficulties in controlling the interferometer in presence of defects (both thermal and cold defects). This work will focus on the interferometer commissioning, highlighting the control challenges to maintain the detector in the working point which maximizes the sensitivity and the duty cycle for scientific data taking., info:eu-repo/semantics/published

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The accretion of matter onto primordial black holes (PBHs) during the dark ages and the subsequent energy injection in the medium should have left imprints on the cosmic microwave background (CMB) anisotropies. Recent works have claimed stringent CMB limits on the PBH abundance, hardly compatible with a PBH interpretation of the gravitational-wave observations of binary black hole (BH) mergers. By using a more realistic accretion model based on hydrodynamical simulations and conservative assumptions for the emission efficiency, we show that CMB limits on the PBH abundance are up to 2 orders of magnitude less stringent than previously estimated between 10 and 104 M⊙. This reopens the possibility that PBHs might explain at the same time (at least a fraction of) the dark matter, some of the LIGO-Virgo-KAGRA binary BH mergers, and the existence of supermassive BHs. More generally, we emphasize that PBH accretion can be a rather complex physical process with velocity dependences that are hard to assess, which introduces large uncertainties in accretion-based limits on the PBH abundance., SCOPUS: ar.j, info:eu-repo/semantics/published

The probability of primordial black hole (PBH) formation is known to be boosted during the Quantum Chromodynamics (QCD) crossover due to a slight reduction of the equation of state. This induces a high peak and other features in the PBH mass distribution. But the impact of this variation during the process of PBH formation has so far not been considered in numerical simulations. In this work we simulate the formation of PBHs by taking into account the varying equation of state at the QCD epoch, compute the over-density threshold using different curvature profiles and find that the resulting PBH mass distributions are significantly impacted. The expected merger rate distributions of early and late PBH binaries is comparable to the ones inferred from the GWTC-3 catalog for dark matter fractions in PBHs within 0.1 < f PBH < 1. The distribution of gravitational-wave events estimated from the volume sensitivity could explain mergers around 30-50 M ⊙, with asymmetric masses like GW190814, or in the pair-instability mass gap like GW190521. However, none of the considered cases leads to a multi-modal distribution with a secondary peak around 8-15 M ⊙, as suggested by the GWTC-3 catalog, possibly pointing to a mixed population of astrophysical and primordial black holes., SCOPUS: ar.j, info:eu-repo/semantics/published

Desertification is one of the most destructive climate-related issues in the Sudan–Sahel region of Africa. As the assessment of desertification is possible by satellite image analysis using vegetation indices (VIs), this study reports on the technical advantages and capabilities of scripting the ‘raster’ and ‘terra’ R-language packages for computing the VIs. The test area which was considered includes the region of the confluence between the Blue and White Niles in Khartoum, southern Sudan, northeast Africa and the Landsat 8–9 OLI/TIRS images taken for the years 2013, 2018 and 2022, which were chosen as test datasets. The VIs used here are robust indicators of plant greenness, and combined with vegetation coverage, are essential parameters for environmental analytics. Five VIs were calculated to compare both the status and dynamics of vegetation through the differences between the images collected within the nine-year span. Using scripts for computing and visualising the VIs over Sudan demonstrates previously unreported patterns of vegetation to reveal climate–vegetation relationships. The ability of the R packages ‘raster’ and ‘terra’ to process spatial data was enhanced through scripting to automate image analysis and mapping, and choosing Sudan for the case study enables us to present new perspectives for image processing., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

The interactions between the geophysical processes and geodynamics of the lithosphere play a crucial role in the geologic structure of the Earth’s crust. The Bangui magnetic anomaly is a notable feature in the lithospheric structure of the Central African Republic (CAR) resulting from a complex tectonic evolution. This study reports on the coherence in the geophysical data and magnetic anomaly field analysed from a series of maps. The data used here include raster grids on free-air altimetric gravity, magnetic EMAG2 maps, geoid EGM2008 model and topographic SRTM/ETOPO1 relief. The data were processed to analyse the correspondence between the geophysical and geologic setting in the CAR region. Histogram equalization of the topographic grids was implemented by partition of the raster grids into equal-area patches of data ranged by the segments with relative highs and lows of the relief. The original data were compared with the equalized, normalized and quadratic models. The scripts used for cartographic data processing are presented and commented. The consistency and equalization of topography, gravity and geoid data were based using GMT modules ‘grdfft’ and ‘grdhisteq’ modules. Using GMT scripts for mapping the geophysical and gravity data over CAR shows an advanced approach to multi-source data visualization to reveal the relationships in the geophysical and topographic processes in central Africa. The results highlighted the correlation between the distribution of rocks with high magnetism in the central part of the Bangui anomaly, and distribution of granites, greenstone belts, and metamorphosed basalts as rock exposure. The correspondence between the negative Bouguer anomaly (<−80 mGal), low geoid values (<−12 m) and the extent of the magnetic anomaly with extreme negative values ranging from −1000 to −200 nT is identified. The integration of the multi-source data provides new insights into the analysis of crustal thicknesses and the average density of the Earth, SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

With methods for processing remote sensing data becoming widely available, the ability to quantify changes in spatial data and to evaluate the distribution of diverse landforms across target areas in datasets becomes increasingly important. One way to approach this problem is through satellite image processing. In this paper, we primarily focus on the methods of the unsupervised classification of the Landsat OLI/TIRS images covering the region of the Qena governorate in Upper Egypt. The Qena Bend of the Nile River presents a remarkable morphological feature in Upper Egypt, including a dense drainage network of wadi aquifer systems and plateaus largely dissected by numerous valleys of dry rivers. To identify the fluvial structure and stream network of the Wadi Qena region, this study addresses the problem of interpreting the relevant space-borne data using R, with an aim to visualize the land surface structures corresponding to various land cover types. To this effect, high-resolution 2D and 3D topographic and geologic maps were used for the analysis of the geomorphological setting of the Qena region. The information was extracted from the space-borne data for the comparative analysis of the distribution of wadi streams in the Qena Bend area over several years: 2013, 2015, 2016, 2019, 2022, and 2023. Six images were processed using computer vision methods made available by R libraries. The results of the k-means clustering of each scene retrieved from the multi-temporal images covering the Qena Bend of the Nile River were thus compared to visualize changes in landforms caused by the cumulative effects of geomorphological disasters and climate-environmental processes. The proposed method, tied together through the use of R scripts, runs effectively and performs favorably in computer vision tasks aimed at geospatial image processing and the analysis of remote sensing data., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

This paper addresses the issue of the satellite image processing using GRASS GIS in the mangrove forests of the Niger River Delta, southern Nigeria. The estuary of the Niger River Delta in the Gulf of Guinea is an essential hotspot of biodiversity on the western coast of Africa. At the same time, climate issues and anthropogenic factors affect vulnerable coastal ecosystems and result in the rapid decline of mangrove habitats. This motivates monitoring of the vegetation patterns using advanced cartographic methods and data analysis. As a response to this need, this study aimed to calculate and map several vegetation indices (VI) using scripts as advanced programming methods integrated in geospatial studies. The data include four Landsat 8-9 OLI/TIRS images covering the western segment of the Niger River Delta in the Bight of Benin for 2013, 2015, 2021, and 2022. The techniques included the ’i.vi’, ’i.landsat.toar’ and other modules of the GRASS GIS. Based on the GRASS GIS ’i.vi’ module, ten VI were computed and mapped for the western segment of the Niger River Delta estuary: Atmospherically Resistant Vegetation Index (ARVI), Green Atmospherically Resistant Vegetation Index (GARI), Green Vegetation Index (GVI), Difference Vegetation Index (DVI), Perpendicular Vegetation Index (PVI), Global Environmental Monitoring Index (GEMI), Normalized Difference Water Index (NDWI), Second Modified Soil Adjusted Vegetation Index (MSAVI2), Infrared Percentage Vegetation Index (IPVI), and Enhanced Vegetation Index (EVI). The results showed variations in the vegetation patterns in mangrove habitats situated in the Niger River Delta over the last decade as well as the increase in urban areas (Onitsha, Sapele, Warri and Benin City) and settlements in the Delta State due to urbanization. The advanced techniques of the GRASS GIS of satellite image processing and analysis enabled us to identify and visualize changes in vegetation patterns. The technical excellence of the GRASS GIS in image, SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

In this paper, we present a new framework for improving soil strength using an advanced method of engineering statistics. The materials included clay till collected in Yttre Ringvägen, southern Sweden. Binders included quicklime, slag and ordinary Portland cement used as pure binders and blended mixtures. We first applied the Response Surface Methodology techniques aimed at binder blend optimisation: 1) Central Composite Design; 2) Box-Behnken Design; 3) Simplex Lattice Design. The Pareto charts were presented for modelling responses from tests with different binders and estimating their effects on soil strength. Finally, to examine the variables important for soil stabilisation, we also evaluated the effect of the amount of binder and the interaction between cement/lime/slag in different ratios: 30-50-20 %; 50-50-0 %; 100-0-0 % The paper highlights the major opportunities and challenges of engineering statistics as a cross-cutting research direction for the issues of civil engineering., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

Libraries with pre-written codes optimize the workflow in cartography and reduce labour intensive data processing by iteratively applying scripts to implementing mapping tasks. Most existing Geographic Information System (GIS) approaches are based on traditional software with a graphical user's interface which significantly limits their performance. Although plugins are proposed to improve the functionality of many GIS programs, they are usually ad hoc in finding specific mapping solutions, e.g. cartographic projections and data conversion. We address this limitation by applying the principled approach of Geospatial Data Abstraction Library (GDAL), library for conversions between cartographic projections (PROJ) and Geographic Resources Analysis Support System (GRASS) GIS for geospatial data processing and morphometric analysis. This research presents topographic analysis of the dataset using scripting methods which include several tools: (1) GDAL, a translator library for raster and vector geospatial data formats used for converting Earth Global Relief Model (ETOPO1) GeoTIFF in XY Cartesian coordinates into World Geodetic System 1984 (WGS84) by the 'gdalwarp' utility; (2) PROJ projection transformation library used for converting ETOPO1 WGS84 grid to cartographic projections (Cassini-Soldner equirectangular, Equal Area Cylindrical, Two-Point Equidistant Azimuthal, and Oblique Mercator); and (3) GRASS GIS by sequential use of the following modules: r.info, d.mon, d.rast, r.colors, d.rast.leg, d.legend, d.northarrow, d.grid, d.text, g.region, and r.contour. The depth frequency was analysed by the module 'd.histogram'. The proposed approach provided a systematic way for morphometric measuring of topographic data and combine the advantages of the GDAL, PROJ, and GRASS GIS tools that include the informativeness, effectiveness, and representativeness in spatial data processing. The morphometric analysis included the computed slope, aspect, profile, and tangential curvatur, SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

My PhD research aims to encompass a detailed chemical and isotopic characterization of “well-preserved” Antarctic meteorites to improve our understanding of the (re-)distribution of various trace elements in specific meteorite types and the effects of the (re-)distribution on radiogenic isotope systematics. As Antarctic meteorites can be affected by alteration, prior to the investigation of the elemental distribution in meteorites and the isotopic effects of the (re-)distribution, the first task of this work has been dedicated to assessing the effects of Antarctic alteration on the chemical and isotopic compositions of ordinary chondrites, the most abundant class of meteorites, and more specifically on H group of ordinary chondrites. The main focus is placed on the systematic study of rare earth elements including their isotope systematics such as Sm-Nd and Lu-Hf.This PhD thesis first demonstrates that the effects of Antarctic alteration on the Sm-Nd and Lu-Hf systems in bulk H chondrites are generally limited and thus the Sm-Nd and Lu-Hf systems preserve their original compositions during Antarctic alteration. Secondly, the underlying mechanism of Antarctic alteration observed in the first part of the PhD study is investigated using in-situ measurement techniques including state-of-the-art laser ablation-inductively coupled plasma-time of flight-mass spectrometry (LA-ICP-TOF-MS). Simultaneously, the potential of LA-ICP-TOF-MS as a novel technique to study the elemental distribution is examined and evaluated. Finally, the distribution of lithophile elements among the constituent minerals in H chondrites is documented at the microscale and their re-distribution during thermal metamorphism in the parent body(ies), i.e. the thermal effects of the lithophile element distribution are quantified and discussed, with a direct link to the heterogeneity recorded in the Sm-Nd and Lu-Hf isotope systematics of bulk chondrites. Overall, this thesis confirms the generally pristine, Cette thèse de doctorat vise à apporter une caractérisation chimique et isotopique détaillée des météorites antarctiques considérées comme « bien conservées" afin d'améliorer notre compréhension de la (re-)distribution de divers éléments en traces dans des types de météorites spécifiques ainsi que pour les systèmes isotopiques radiogéniques. Comme les météorites antarctiques peuvent être affectées par l'altération, avant l'étude de la distribution élémentaire dans les météorites et les effets isotopiques de la (re-)distribution, la première tâche de ce travail a été consacrée à l'évaluation des effets de l'altération antarctique sur les compositions chimiques et isotopiques des chondrites ordinaires, la classe la plus abondante de météorites, et plus précisément du groupe H des chondrites ordinaires. L'accent est mis sur l'étude systématique des éléments des terres rares, y compris leur systématique isotopique Sm-Nd et Lu-Hf.Ce travail démontre d'abord que les effets de l'altération antarctique pour les systèmes Sm-Nd et Lu-Hf dans les chondrites de type H sont généralement limités et donc que ces systèmes conservent leurs compositions d'origine lors de l'altération antarctique. Deuxièmement, le mécanisme sous-jacent de l'altération antarctique a été étudié à l'aide de techniques de mesure in situ, notamment l'ablation laser et la spectrométrie de masse plasma-temps de vol à couplage inductif (LA-ICP-TOF -MS). Simultanément, le potentiel du LA-ICP-TOF-MS en tant que nouvelle technique pour étudier la distribution élémentaire a été examiné et évalué. Enfin, la distribution des éléments lithophiles parmi les minéraux constitutifs des chondrites H est documentée à l'échelle microscopique et leur redistribution lors du métamorphisme thermique dans le ou les corps parents. Ainsi, les effets thermiques de la distribution des éléments lithophiles sont quantifiés et discutés, avec un lien direct avec l'hétérogénéité enregistrée dans la systématique isotopique Sm-Nd et Lu-Hf, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

The radiation of bioturbation during the Ediacaran–Cambrian transition has long been hypothesized to have oxygenated sediments, triggering an expansion of the habitable benthic zone and promoting increased infaunal tiering in early Paleozoic benthic communities. However, the effects of bioturbation on sediment oxygen are underexplored with respect to the importance of biomixing and bioirrigation, two bioturbation processes which can have opposite effects on sediment redox chemistry. We categorized trace fossils from the Ediacaran and Terreneuvian as biomixing or bioirrigation fossils and integrated sedimentological proxies for bioturbation intensity with biogeochemical modeling to simulate oxygen penetration depths through the Ediacaran–Cambrian transition. Ultimately, we find that despite dramatic increases in ichnodiversity in the Terreneuvian, biomixing remains the dominant bioturbation behavior, and in contrast to traditional assumptions, Ediacaran–Cambrian bioturbation was unlikely to have resulted in extensive oxygenation of shallow marine sediments globally., SCOPUS: ar.j, info:eu-repo/semantics/published

Context. Determining ages of stars for reconstructing the history of the Milky Way remains one of the most difficult tasks in astrophysics. This involves knowing when it is possible to relate the stellar mass with its age and when it is not. The young a-rich (YAR) stars present such a case in which we are still not sure about their ages because they are relatively massive, implying young ages, but their abundances are a-enhanced, which implies old ages. Aims. We report the results from new observations from a long-Term radial-velocity-monitoring campaign complemented with high-resolution spectroscopy, as well as new astrometry and seismology of a sample of 41 red giants from the third version of APOKASC, which includes YAR stars. The aim is to better characterize the YAR stars in terms of binarity, mass, abundance trends, and kinematic properties. Methods. The radial velocities of HERMES, APOGEE, and Gaia were combined to determine the binary fraction among YAR stars. In combination with their mass estimate, evolutionary status, chemical composition, and kinematic properties, it allowed us to better constrain the nature of these objects. Results. We found that stars with M< M were all single, whereas stars with M> Mcould be either single or binary. This is in agreement with theoretical predictions of population synthesis models. Studying their [C/N], [C/Fe], and [N/Fe], trends with mass, it became clear that many YAR stars do not follow the APOKASC stars, favoring the scenario that most of them are the product of mass transfer. Our sample further includes two likely undermassive stars, that is to say of such as low mass that they cannot have reached the red clump within the age of the Universe, unless their low mass is the signature of mass loss in previous evolutionary phases. These stars do not show signatures of currently being binaries. Both YAR and undermassive stars might show some anomalous APOGEE abundances for the elements N, Na, P, K, and Cr; although, hig, SCOPUS: ar.j, info:eu-repo/semantics/published

In this paper, we describe two related scripting methods of cartographic data processing and visualization that provide 2D and 3D mapping of Japan with different algorithm complexity. The first algorithm utilizes Generic Mapping Toolset (GMT), which is known as an advanced console-based program for spatial data processing. The modules of GMT combine the functionality of scripting with the aspects of geoinformatics, which is especially effective for the rapid analysis of large geospatial datasets, multi-format data processing, and mapping in 2D and 3D modes. The second algorithm presents the use of the R programming language for cartographic visualization and spatial analysis. This R method utilizes the packages ‘tmap’, ‘raster’, ‘maps’, and ‘mapdata’ to model the morphometric elements of the Japanese archipelago, such as slope, aspect, hillshade and elevation. The general purpose graphical package ‘ggplot2’ of R was used for mapping the prefectures of Japan. The two scripting approaches demonstrated an established correspondence between the programming languages and cartography determined with the use of scripts for data processing. They outperform several well-known and state-of-the-art GIS methods for mapping due to their high automation of data processing. Cartography has largely reflected recent advances in data science, the rapid development of scripting languages, and transfer in the approaches of data processing. This extends to the shift from the traditional GIS to programming languages. As a response to these new challenges, we demonstrated in this paper the advantages of using scripts in mapping, which consist of repeatability and the flexible applicability of scripts in similar works., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

We propose a probabilistic approach to gauge the plausibility of a genetic link between a distal ejecta and a known impact structure, considering the only possible alternative that the distal ejecta could originate from an unknown impact site. We exemplify this approach in the case of three tektite strewn fields related to three known impact structures—the belizites, related to Pantasma (Nicaragua), the ivorites, related to Bosumtwi (Ghana), the moldavites, related to Ries (Germany), as well as on Manson crater ejecta. The computed probability for the unknown meteoritic impact is about 1% or less for these four cases studies., SCOPUS: ar.j, info:eu-repo/semantics/published

We present the development and evaluation of MOM6-COBALT-NWA12 version 1.0, a 1/12 model of ocean dynamics and biogeochemistry in the northwest Atlantic Ocean. This model is built using the new regional capabilities in the MOM6 ocean model and is coupled with the Carbon, Ocean Biogeochemistry and Lower Trophics (COBALT) biogeochemical model and Sea Ice Simulator version-2 (SIS2) sea ice model. Our goal was to develop a model to provide information to support living-marine-resource applications across management time horizons from seasons to decades. To do this, we struck a balance between a broad, coastwide domain to simulate basin-scale variability and capture cross-boundary issues expected under climate change; a high enough spatial resolution to accurately simulate features like the Gulf Stream separation and advection of water masses through finer-scale coastal features; and the computational economy required to run the long simulations of multiple ensemble members that are needed to quantify prediction uncertainties and produce actionable information. We assess whether MOM6-COBALT-NWA12 is capable of supporting the intended applications by evaluating the model with three categories of metrics: basin-wide indicators of the model's performance, indicators of coastal ecosystem variability and the regional ocean features that drive it, and model run times and computational efficiency. Overall, both the basin-wide and the regional ecosystem-relevant indicators are simulated well by the model. Where notable model biases and errors are present in both types of indicator, they are mainly consistent with the challenges of accurately simulating the Gulf Stream separation, path, and variability: for example, the coastal ocean and shelf north of Cape Hatteras are too warm and salty and have minor biogeochemical biases. During model development, we identified a few model parameters that exerted a notable influence on the model solution, including the horizontal viscosity, m, SCOPUS: ar.j, info:eu-repo/semantics/published

We introduce PARASO, a novel five-component fully coupled regional climate model over an Antarctic circumpolar domain covering the full Southern Ocean. The state-of-The-Art models used are the fast Elementary Thermomechanical Ice Sheet model (f.ETISh) v1.7 (ice sheet), the Nucleus for European Modelling of the Ocean (NEMO) v3.6 (ocean), the Louvain-la-Neuve sea-ice model (LIM) v3.6 (sea ice), the COnsortium for Small-scale MOdeling (COSMO) model v5.0 (atmosphere) and its CLimate Mode (CLM) v4.5 (land), which are here run at a horizontal resolution close to 1/4g .One key feature of this tool resides in a novel two-way coupling interface for representing ocean-ice-sheet interactions, through explicitly resolved ice-shelf cavities. The impact of atmospheric processes on the Antarctic ice sheet is also conveyed through computed COSMO-CLM-f.ETISh surface mass exchange. In this technical paper, we briefly introduce each model's configuration and document the developments that were carried out in order to establish PARASO. The new offline-based NEMO-f.ETISh coupling interface is thoroughly described. Our developments also include a new surface tiling approach to combine open-ocean and sea-ice-covered cells within COSMO, which was required to make this model relevant in the context of coupled simulations in polar regions. We present results from a 2000-2001 coupled 2-year experiment. PARASO is numerically stable and fully operational. The 2-year simulation conducted without fine tuning of the model reproduced the main expected features, although remaining systematic biases provide perspectives for further adjustment and development., SCOPUS: ar.j, info:eu-repo/semantics/published

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We present a directed search for continuous gravitational wave (CW) signals emitted by spinning neutron stars located in the inner parsecs of the Galactic Center (GC). Compelling evidence for the presence of a numerous population of neutron stars has been reported in the literature, turning this region into a very interesting place to look for CWs. In this search, data from the full O3 LIGO-Virgo run in the detector frequency band [10,2000] Hz have been used. No significant detection was found and 95% confidence level upper limits on the signal strain amplitude were computed, over the full search band, with the deepest limit of about 7.6×10-26 at ≃142 Hz. These results are significantly more constraining than those reported in previous searches. We use these limits to put constraints on the fiducial neutron star ellipticity and r-mode amplitude. These limits can be also translated into constraints in the black hole mass-boson mass plane for a hypothetical population of boson clouds around spinning black holes located in the GC., info:eu-repo/semantics/published

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Detection of a gravitational-wave signal of non-astrophysical origin would be a landmark discovery, potentially providing a significant clue to some of our most basic, big-picture scientific questions about the Universe. In this white paper, we survey the leading early-Universe mechanisms that may produce a detectable signal—including inflation, phase transitions, topological defects, as well as primordial black holes—and highlight the connections to fundamental physics. We review the complementarity with collider searches for new physics, and multimessenger probes of the large-scale structure of the Universe., SCOPUS: ar.j, info:eu-repo/semantics/published

We present the results of a model-based search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1 using LIGO detector data from the third observing run of Advanced LIGO and Advanced Virgo. This is a semicoherent search that uses details of the signal model to coherently combine data separated by less than a specified coherence time, which can be adjusted to balance sensitivity with computing cost. The search covered a range of gravitational-wave frequencies from 25 to 1600 Hz, as well as ranges in orbital speed, frequency, and phase determined from observational constraints. No significant detection candidates were found, and upper limits were set as a function of frequency. The most stringent limits, between 100 and 200 Hz, correspond to an amplitude h0 of about 10−25 when marginalized isotropically over the unknown inclination angle of the neutron star's rotation axis, or less than 4 × 10−26 assuming the optimal orientation. The sensitivity of this search is now probing amplitudes predicted by models of torque balance equilibrium. For the usual conservative model assuming accretion at the surface of the neutron star, our isotropically marginalized upper limits are close to the predicted amplitude from about 70 to 100 Hz; the limits assuming that the neutron star spin is aligned with the most likely orbital angular momentum are below the conservative torque balance predictions from 40 to 200 Hz. Assuming a broader range of accretion models, our direct limits on gravitational-wave amplitude delve into the relevant parameter space over a wide range of frequencies, to 500 Hz or more., 0, info:eu-repo/semantics/published

Intermediate-mass black holes (IMBHs) span the approximate mass range 100-105 M· ,between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M· providing direct evidence of IMBH formation. Here, we report on a dedicated search of O3 data for further IMBH binary mergers, combining both modeled (matched filter) and model-independent search methods. We find some marginal candidates, but none are sufficiently significant to indicate detection of further IMBH mergers. We quantify the sensitivity of the individual search methods and of the combined search using a suite of IMBH binary signals obtained via numerical relativity, including the effects of spins misaligned with the binary orbital axis, and present the resulting upper limits on astrophysical merger rates. Our most stringent limit is for equal mass and aligned spin BH binary of total mass 200 M· and effective aligned spin 0.8 at 0.056 Gpc-3 yr-1 (90% confidence), a factor of 3.5 more constraining than previous LIGO-Virgo limits. We also update the estimated rate of mergers similar to GW190521 to 0.08 Gpc-3 yr-1, 0, info:eu-repo/semantics/published

We present the first results from an all-sky all-frequency (ASAF) search for an anisotropic stochastic gravitational-wave background using the data from the first three observing runs of the Advanced LIGO and Advanced Virgo detectors. Upper limit maps on broadband anisotropies of a persistent stochastic background were published for all observing runs of the LIGO-Virgo detectors. However, a broadband analysis is likely to miss narrowband signals as the signal-to-noise ratio of a narrowband signal can be significantly reduced when combined with detector output from other frequencies. Data folding and the computationally efficient analysis pipeline, PyStoch, enable us to perform the radiometer map-making at every frequency bin. We perform the search at 3072 HEALPix equal area pixels uniformly tiling the sky and in every frequency bin of width 1/32 Hz in the range 20-1726 Hz, except for bins that are likely to contain instrumental artefacts and hence are notched. We do not find any statistically significant evidence for the existence of narrowband gravitational-wave signals in the analyzed frequency bins. Therefore, we place 95% confidence upper limits on the gravitational-wave strain for each pixel-frequency pair, the limits are in the range (0.030-9.6)×10-24. In addition, we outline a method to identify candidate pixel-frequency pairs that could be followed up by a more sensitive (and potentially computationally expensive) search, e.g. a matched-filtering-based analysis, to look for fainter nearly monochromatic coherent signals. The ASAF analysis is inherently independent of models describing any spectral or spatial distribution of power. We demonstrate that the ASAF results can be appropriately combined over frequencies and sky directions to successfully recover the broadband directional and isotropic results., 0, info:eu-repo/semantics/published