Search publications of the members of the Royal Belgian institute of natural Sciences
-
Abeilles de Belgique et des régions limitrophes (Insecta: Hymenoptera: Apoidea) Famille Halictidae
-
Diversity of bone microstructure in mammals
-
Effects of elevational range shift on the morphology and physiology of a carabid beetle invading the sub-Antarctic Kerguelen Islands
-
Skilled in camouflage: Barbary sheep in the elite cemetery
-
Samenvatting v.d. volledige milieuvergunningsprocedure in de vorm v.e. flow-chart
-
The new stick insect genus Medauromorpha gen. nov. with one new species from Vietnam and notes on Medauroidea Zompro, 2000 (Phasmida: Phasmatidae: Clitumninae)
-
The Picasso stick insect. A striking new species of Calvisia from Vietnam with notes on captive breeding and new methods for incubation of eggs (Phasmida: Diapheromeridae: Necrosciinae)
-
Assessing the radiocarbon freshwater reservoir effect for a Northwest-European river system (the Schelde basin, Belgium)
- The freshwater reservoir effect (FRE) for the Schelde basin (Belgium) is assessed for the Roman, Medieval and early Post-medieval periods by comparing historical and archaeological dates from individual archaeological deposits with radiocarbon dates on the remains of freshwater fish and terrestrial mammals from those same deposits. This is the first time such an assessment has been attempted for the Schelde basin. The FRE offsets prove to be substantial for the historical periods considered. They also differ markedly between fish species and between size classes of a single species. These observations have implications for the evaluation of radiocarbon dates obtained on archaeological remains of humans (and animals) with a substantial amount of freshwater fish into their diet. The data obtained in this study suggest that it will not be easy to correct for any FRE.
-
StratigrapheR: making and using lithologs in R
- StratigrapheR is an open-source integrated stratigraphy package. It is available in the free software environment R (https://CRAN.R-project.org/package=StratigrapheR) and is designed to generate lithologs in a semi-automated way, to process stratigraphical information, and to visualize any plot along the lithologs in the R environment. The basic graphical principle behind StratigrapheR is the incremental addition of elements to a drawing: a plot is opened, and graphical elements are successively added. This allows compartmentalisation of the drawing process, as well as the superposition of different plots for comparison. For instance a litholog of a single section can be written as a single function including all the drawing sub-functions, and be integrated in a larger plot, for instance to be correlated to other sections or to show proxy data. The StratigrapheR package is designed for efficient work, and minimum coding, while still allowing versatility. The lithological information of beds (upper and lower boundary, hardness, lithology, etc.) is converted into polygons. All polygons are drawn together using a single function, and each polygon can have its personalised symbology allowing to distinguish lithologies. A similar workflow can be used for plotting proxies while distinguishing each sample by their lithology. Vector graphics can be imported as SVG files, and precisely drawn with the lithologs to serve as symbols or complex elements. Every type of symbol is plotted by calling one single function which repeats the drawing for each occurrence of the represented feature. This illustrates that the amount of work invested to make lithologs using StratigrapheR is related to their complexity rather than their length: a long but monotonous litholog (e.g. of marl-limestone alternations) only takes a few lines of code to generate. The StratigrapheR package also provides a set of functions to deal with selected stratigraphic intervals (for instance in the [0,1[ form): they allow simplification, merging, inversion and visualisation of intervals, as well as identifying the samples included in the given intervals, and characterising the relation of the intervals with each other (overlap, neighbouring, etc.). StratigrapheR includes PDF and SVG generation of plots, of any dimension. The generated PDF can even store multiple plots in a single file (each plot on a different page) to document data processing comprehensively.
-
A posteriori verification methodology for astrochronology: a step further to improve the falsifiability of cyclostratigraphy
- Cyclostratigraphy is increasingly used to improve the Geologic Time Scale and our understanding of past climatic systems. However, except in a few existing methodologies, the quality of the results is often not evaluated. We propose a new methodology to document this quality, through a decomposition of a signal into a set of narrow band components from which instantaneous frequency and amplitude can be computed, using the Hilbert transform. The components can be obtained by Empirical Mode Decomposition (EMD), but also by filtering a signal (be it tuned or not) in any relevant way, and by subsequently performing EMD on the signal minus its filtered parts. From that decomposition, verification is performed to estimate the pertinence of the results, based on different concepts that we introduce: Integrity quantifies to what extent the sum of the components is equal to the signal. It is defined as the cumulated difference between (1) the signal, and (2) the summed components of the decomposition. EMD fulfils integrity by design, except for errors caused by floating-decimal arithmetic. Ensemble Empirical Mode Decomposition (EEMD) may fail to satisfy integrity unless noisy realisations are carefully chosen in the algorithm to cancel each other when averaging the realisations. We present such an algorithm implemented in R: “extricate”, which performs EEMD in a few seconds. Parsimony checks that the decomposition does not generate components that heavily cancel out. We propose to quantify it as the ratio between (1) the cumulated absolute values of each component (except the trend), and (2) the cumulated absolute values of the signal (minus the trend). The trend should be ignored in the calculation, because an added trend decreases the parsimony estimation of a similar decomposition. IMF departure (IMFD) quantifies the departure of each component to the definition of intrinsic mode functions (IMF), from which instantaneous frequency can reliably be computed. We define it as the mean of the absolute differences of the base 2 logarithms of frequencies obtained using (1) a robust generalized zero-crossing method (GZC, which simplifies the components into extrema separated by zero-crossings) and (2) a more local method such as the Hilbert Transform. Reversibility is the concept that all initial data points are preserved, even after linear interpolation and tuning. This allows to revert back to the original signal and discuss the significance of each data point. To facilitate reversibility we introduce the concept of quanta (smallest depth or time interval having significance for a given sampling) and an algorithm computing the highest rational common divisor of given values in R: “divisor”. This new methodology allows to check the final result of cyclostratigraphic analysis independently of how it was performed (i.e. a posteriori). Once the above-mentioned concepts are taken into account, the instantaneous frequencies, ratios of frequencies and amplitudes of the components can be computed and used to interpret the pertinence of the analysis in a geologically meaningful way. The instantaneity and independence of frequency and amplitude so obtained open a new way of performing time-series analysis.
-
Book review of « Current status of stratigraphic units named from Belgium and adjacent areas »
-
State of the art on the “calamine” - type zinc deposits of Belgium
-
La carte géologique de Wallonie
-
La mémoire du sous-sol
-
L’âge des rochers d’escalade de Belgique.
-
Historical variations in the isotopic composition of atmospheric zinc deposition from a zinc smelter
-
Hommage d’un géologue à Lambert Grailet
-
Geology of the Ardenne Anticlinorium, in the Amberloup - La Roche-en-Ardenne - Houffalizesector : The faults of the La Roche Syncline and the overturned Taverneux Anticline
-
Les sépultures des XVII-XVIIIèmes siècles fouillées en 1938 à Ngongo Mbata (République Démocratique du Congo) : recrutement et état sanitaire
- This article seeks to bring new insights on funerary practices of Ngongo Mbata (17-18th cent. AD), a Kongo Kingdom’s major site. The excavation that took place between 1938 and 1942, has delivered a number of tombs. The skeletal assemblage, curated in the Royal Belgian Institute of Natural Sciences, consists of 38 human skeletons. The bones are badly preserved. With the main aim of conducting the biological profile of Ngongo Mbata’s population (estimation of age, sex and stature). This was completed by a more specific study of dental pathologies and morphological variations to enrich this content. Finally, the studied population was placed in a larger geographical context to shed new light on populations in Central Africa. Despite the bad preservation of skeletons, our study has revealed a high presence of young individuals (less than 30 years old). Besides the dental pathological study has shown, a low frequency of dental carious, dental calculus or periodontal diseases, which seems to indicate a relatively good dental health. Beyond the lifestyles, this research has also revealed different aspects of the funerary practices of Kongo’s society. In the future, isotopic, micro-wear or dental metric variations research, could increase our knowledge and open new perspectives on diet, mobility and geographical origin of this population.
-
Waulsort Caverne X: A new cave site with Early Mesolithic human remains in Belgium.
- Caverne X in Waulsort (Namur province, Belgium), excavated in the 19 th century, revealed a burial site which was unexpectedly dated to the Final Upper Paleolithic (10,820 ± 80 BP, OxA-6856) in the 1990's. A re-examination of the collection and a new radiocarbon dating program was recently undertaken. The dates obtained on four left femurs (9285 ± 30 BP, ETH-74725; 9310 ± 30 BP, ETH-74726; 9340 ± 30 BP, ETH-74727; 9300 ± 30 BP, ETH-74728) revealed that the remains should in fact be attributed to the Early Mesolithic, ISSN 0259-3548 25 MM 28:2 (December 2020) consistent with 24 other 14 C dates obtained for eight cave sites in the Meuse Basin which range from ca. 9600 BP to 9000 BP. Caverne X contained 544 human remains belonging to at least nine individuals (one fetus, one perinatal/young child, one teenager, two adolescents/young adults and four adults), and 66 faunal remains consisting mainly of intrusive animals with the possible exception of a cervid antler, and one artefact (a small flint blade). Other than ochre deposits, all alterations (breakage, surface abrasion, impact scars and concretions) are post-depositional in origin. Carbon and nitrogen stable isotope analysis indicates a diet primarily based on terrestrial resources from an open landscape with proteins provided by large herbivores. Our study shows that Caverne X fits well with results already obtained for the Meuse Basin cave burials in terms of chronology, minimum number of individuals, funerary rituals and diet.
