Search results for "CTA"
showing 10 items of 9379 documents
Tectonic evolution of the northern Austral-Magallanes basin in the Southern Patagonian Andes from provenance analysis
2019
We studied the northern tip of the Austral-Magallanes basin in the Southern Patagonian Andes, between the Buenos Aires Lake and the Mayer River at 46°35′ SL and 48°35′ SL, respectively. Proposed objectives were: i) to differentiate Mesozoic-Cenozoic tectonostratigraphic units and, ii) to characterize the different deformational events that took place in the area linked to a variable regional geodynamic context. Sandstones provenance analysis was performed on the Aptian - Albian compressive retroarc deposits and Cenozoic foreland deposits. Studied samples were classified using tectonic discrimination diagrams which show: i) for Cretaceous rocks a dominant sediment source from a recycled orog…
The metamorphic rocks of the Nunatak Viedma in the Southern Patagonian Andes: Provenance sources and implications for the early Mesozoic Patagonia-An…
2019
The Nunatak Viedma within the Southern Patagonian Icefield has been considered as a volcanic center based on its geomorphologic features, despite the fact that field explorations by Eric Shipton determined its metamorphic nature 70 years ago. We carried out fieldwork to characterize this isolated outcrop and performed the first U-Pb dating in detrital zircons from the basement rocks located inside the Southern Patagonian Icefield. We recognized very-low grade metamorphic rocks, corresponding principally to metapelites and metapsammites, and scarce metabasites. Detrital zircons in three metapsammitic samples (composite group of 240 grains) yielded prominent age population peaks at ∼1090, ∼96…
Citizen Science in the Natural Sciences
2021
AbstractThe natural sciences include the life and physical sciences and study nature through observing and understanding phenomena, testing hypotheses, and performing experiments. Key principles such as reliability, validity, objectivity, and predictability are achieved through transparent assumptions, methods, data, and interpretations as well as multidisciplinarity.In this chapter we present insights into the genesis of citizen science in the natural sciences and reflect on the intellectual history of the natural sciences in relation to citizen science today. Further, we consider the current scientific approaches and achievements of natural science projects, which are applying citizen sci…
Early Diagnosis of Vegetation Health From High-Resolution Hyperspectral and Thermal Imagery: Lessons Learned From Empirical Relationships and Radiati…
2019
[Purpose of Review] We provide a comprehensive review of the empirical and modelling approaches used to quantify the radiation–vegetation interactions related to vegetation temperature, leaf optical properties linked to pigment absorption and chlorophyll fluorescence emission, and of their capability to monitor vegetation health. Part 1 provides an overview of the main physiological indicators (PIs) applied in remote sensing to detect alterations in plant functioning linked to vegetation diseases and decline processes. Part 2 reviews the recent advances in the development of quantitative methods to assess PI through hyperspectral and thermal images.
Change in dominance determines herbivore effects on plant biodiversity
2018
Herbivores alter plant biodiversity (species richness) in many of the world’s ecosystems, but the magnitude and the direction of herbivore effects on biodiversity vary widely within and among ecosystems. One current theory predicts that herbivores enhance plant biodiversity at high productivity but have the opposite effect at low productivity. Yet, empirical support for the importance of site productivity as a mediator of these herbivore impacts is equivocal. Here, we synthesize data from 252 large-herbivore exclusion studies, spanning a 20-fold range in site productivity, to test an alternative hypothesis—that herbivore-induced changes in the competitive environment determine the response …
Accuracy of IKONOS for mapping benthic coral-reef habitats: a case study from the Puerto Morelos Reef National Park, Mexico
2012
International audience; Reefs are being threatened by global warming, natural disasters, and the increased pressure of the global population. These habitats are in urgent need of mapping at high resolution so that these threats can be quantified. Remote sensing can potentially provide such quantitative data. In this article, we attempt to map benthic coral-reef habitats at the Puerto Morelos Reef National Park in Yucatan Peninsula (Mexico) and to assess the accuracy of the technique in providing a baseline data for future monitoring of changes and evolution of the reef system. An IKONOS image was used in combination with checkpoint ground sampling and classified using a supervised maximum l…
Managing boreal forests for the simultaneous production of collectable goods and timber revenues
2016
Timber Production is an economically important provisioning ecosystem service in forests, but is often in conflict with the provision of other ecosystem services. In multifunctional forestry, the production of timber and non-timber ecosystem services should coexist in the same landscape. To this end, we explored the capacity of a boreal landscape to simultaneously produce collectable goods − bilberry (Vaccimium myrtillus L.), cowberry (Vaccinium vitis-idaea L.) and cep (Boletus edulis Bull.) − alongside timber revenues. We also identified optimal forest management plans to achieve this. Furthermore, we analyzed trade-offs between collectable good yields and timber production, as well as bet…
New fossil arthropods (Notostraca and Insecta: Syntonopterida) in the Continental Middle Permian of Provence (Bas-Argens Basin, France).
2009
9 pages; Apart frequent and relatively common ichnites, only a few body fossils (Ostracoda) have been mentioned in the Red Continental Permian formations of Provence till these last years. During 2006 and 2007 field researches, new arthropods have been discovered in the Pradineaux Formation of the Bas-Argens. They are Triopsidae (Crustacea, Notostraca) and an insect wing (Syntonopteridae) corresponding to a new genus and species Gallolithoneura butchlii gen. et sp. n. This latter is the first insect record in the Permian of Provence and the youngest one of this enigmatic Carboniferous paleopteran family. As in the other French Permian basins (Lodève, Saint-Affrique), these discoveries demon…
Nomenclatural revision concerning some genera of the Order Trigoniida (Bivalvia)
2018
The authors have become aware of a couple of nomenclatural conflicts involving Mesozoic trigoniid genera, which are in need of clarification and proposal of replacement names: The case of Protrigonia. The subgenus Trigonia (Protrigonia) Guo, 1985 (p. 204, 269; type species Trigonia (Protrigonia) yunnanensis Guo, 1985), was proposed to encompass those species referred to the genus Trigonia which, according to that author, have small and nearly smooth shells and relatively weak teeth. Guo (1985) also included other Triassic species: Trigonia gaytani (von Klipstein, 1843) and Trigonia zlambachiensis Haas, 1909. According to Fang et al. (2009, p. 55) there was a wrong translation from the Chine…
Values and challenges in the assessment of coprophilous fungi according to the IUCN Red List criteria: the case study of Poronia punctata (Xylariales…
2020
Coprophilous fungi are specialized microorganisms, playing key roles in ecosystems and in several other contexts, whose protection requires more substantial efforts. This paper aims to highlight and discuss valuable and critical aspects faced during the process of the threat status assessment of Poronia punctata, providing inspirations for future conservation actions.