Curvature estimates for spacelike hypersurfaces in de Sitter space

Local estimates of the maximal curvatures of admissible spacelike hypersurfaces in de Sitter space for k-symmetric curvature functions are obtained. They depend on interior and boundary data. The curvature function is also assumed to depend on the tilt/slope of the hypersurface and an additional growth condition holds

Going with the flow: Sedimentary processes along karst conduits within Chalk aquifers, northern France

Sediment-filled caves, conduits and voids are common inmany karst regions. These voids and the sediment they contain are important palaeoclimatic and palaeoenvironmental archives, but often have an adverse impact on engineering projects, mineral extraction and hydrogeology.Most studies into fluvial sedimentation in karst aquifers have focussed on more traditional karst areas. However, the nature and extent of fluvial sedimentation within caves and conduits in the important Upper Cretaceous Chalk Group aquifer (NW and Central Europe), and their impacts are lesswell known. This is principally due to a lack of accessible Chalk caveswith exposed 3D sediment archives for study. Fortunately, the discovery of the World's longest Chalk cave system by underground quarrying at Caumont in the Seine valley near Rouen, northern France, has exposed numerous sediment sections along 2.4 km of passage. Detailed analysis of the stratigraphy, mineralogy, sedimentology, provenance and the chronology of the exposed sediments including the novel use of Gamma-ray spectrometry, reveals complex stratigraphy and lateral facies distribution along a karst conduit. The depositional model comprises five allostratigraphical units since the mid-Chibanian, separated by periods of erosion. The units are derived from hyper-concentrated and sediment-laden flows, and include thalweg, channel, slackwater, backswamp speleothem facies and debris flow deposits that are interbedded. Speleothems precipitated during MIS 7, 6, 5e and 1. During MIS 7–6, detrital sediments filled almost all Chalk conduits, similar to other caves in the European Atlantic Margin, coevally with the Penultima (Saalian) Glacial Cycle and a maximum of the Earth eccentricity. Detrital sediments are derived from the erosion of local Chalk bedrocks as well as metamorphic and igneous rocks of remote areas, such as Morvan massif and Massif Central. The depositional model is consistent with the conception of the Chalk as a karst aquifer. Significant sediment aggradation caused upwards dissolution (paragenesis), conduit occlusion and subsequent genesis of new conduits by flow diversion, potentially altering the functioning of the chalk aquifer and the interpretation of Chalk hydrogeology (e.g., dye-tracing tests).PALECONOR project funded by Région NormandieComité Régional de Spéléologie de NormandieMuséum National d'Histoire Naturelle, Paris)France regional council's Sesame and Labex BcDiv programmesPlan Andaluz de Investigación, Desarrollo e Innovación 2020 (Junta de Andalucía, Spain

A GIS‑supported Multidisciplinary Database for the Management of UNESCO Global Geoparks: the Courel Mountains Geopark (Spain)

Funding for open access charge: Universidad de Granada/CBUA. The work was funded by the Courel Mountains UGGp.The management of a UNESCO Global Geopark (UGGp) requires a vast wealth of miscellaneous scientific knowledge that can be successfully organised using a Geographical Information System (GIS). This paper presents a pragmatic GIS database to assist in the suitable governance of the Courel Mountains UGGp (2017) in Northwest Spain. The database is structured in 66 coverages compiled from public sources and previous works or produced through traditional mapping (combining fieldwork and photointerpretation) and GIS tools. The acquired data was later homogenised and validated by a multidisciplinary team and archived in independent coverages. Forty thematic maps illustrate the broad range of cartographic information included in the GIS database. Among them, 25 basic maps provide an overview of the UGGp and 15 new maps focus on crosscutting and technical issues. All maps illustrate the huge potential of GIS to create new resources combining coverages and adapting the legend according to their purpose and audience. The database facilitates the suitable publishing of consistent outputs (e.g., brochures, books, panels, webpages, web serves), as well as the elaboration of technical data to assist the park management. The database furnishes information on the design of education actions, touristic routes, activities and Geopark facilities. The GIS database is also a supportive tool for scientific research and provides the necessary knowledge to conduct geoconservation actions based on land use, geological hazards and the occurrence of natural and cultural heritages. Altogether, the GIS database constitutes a powerful instrument for policy-making, facilitating the identification and evaluation of alternative strategy plans.Universidad de Granada/CBUACourel Mountains UGG

Human resource allocation to multiple projects based on members’ expertise, group heterogeneity and social cohesion

Project managers regularly allocate human resources to construction projects. This critical task is usually executed by fulfilling the minimum project staffing requirements normally based around the quantity and competence of project members. However, research has shown that team performance can increase by up to 10% and 18%, respectively, as a consequence of the group members’ heterogeneity and social cohesion. Also, there is currently no practical quantitative tool which incorporates these aspects to allow project managers to achieve this task efficiently and objectively. A new quantitative model for the effective allocation of human resources to multiple projects, which takes into account group heterogeneity and social cohesion is proposed. This model is easy to build, update and use in real project environments with the use of a spreadsheet and a basic optimization engine (e.g. Excel Solver). A case study is proposed and solved with a Genetic Algorithm to illustrate the model implementation. Finally, a validation example is provided to exemplify how group heterogeneity and social cohesion condition academic achievement in an academic setting

Small- scale structure of infaunal polychaete communities in an estuarine environment: Methodological approach

12 páginas, 3 figuras, 2 tablasThis study compares different methods for the estimation of minimal areas (viz. species/area curves, diversity/area curves, similarity/area curves, variance/mean ratio vs. area curves) as community structure descriptions. The comparisons are based upon two polychaete taxocoenoses from muddy and sandy habitats, located in a semienclosed shallow-water Mediterranean bay (Alfacs Bay, Ebro Delta, NW Mediterranean).The mud community appeared to be very homogeneous, with very low diversity. This community displayed high structural simplicity (related to various stress factors), and therefore, qualifies as a physically controlled community). The diversity index was stabilized for areas of 37 cm2, quantitative similarity (Kulcznski index) was higher than 0·7 for areas of 90 cm2, and density of individuals was stabilized for areas of 120 cm2. Therefore, and area of 120 cm2 is suggested as being representative of the community structure. However, it was impossible to define a qualitatively adequate sampling area ( more than 300cm2). The sand community displayed hig structural complexity, with hig species richness and high diversity. This community was characterized by high environmental stability and high variability of microhabitats, as is frequent in biologically accomodated communities. Tne number of individuals became homogeneous for areas of 600-1000 cm2, diversity was stabilized around 300 cm2 and a Kulczynski similarity index of 0·7 was alredy attained at areas of 1000cm2. Thus, a quantitatively representative sampling area of between 700 and 1000 cm2 was suggested. Moreover, the more general pattern of species distribution (with an important set of common species) was directly related to the relatively low qualitative minimal area (400 cm2)Peer reviewe

Mammalian turnover as an indicator of climatic and anthropogenic landscape modification: A new Meghalayan record (Late Holocene) in northern Iberia

Acknowledgements AB.M-A. developed part of this research as part of the ERC Consoli- dator Grant (SUBSILIENCE ref. 818299). We thank J.A. Delgado for his technical work on studying macromammal assemblage. Financial sup- port was provided by the Bilbao Port Authority (Autoridad Portuaria de Bilbao) within the project “Estabilizaci´on del sector occidental de la Cantera de Punta Lucero en el Puerto de Bilbao”. We are also grateful to Juan Manuel L´opez-García and the anonymous reviewer for their sug- gestions and comments that strongly improved the manuscript.Supplementary data to this article can be found online at https://doi.org/10.1016/j.palaeo.2023.111476The Punta Lucero III cave is a natural trap where abundant vertebrate remains were accumulated during the Meghalayan (Late Holocene). To better understand the paleoenvironmental conditions in which this record was accumulated, the micromammal assemblage, comprising a minimum number of 1396 individuals belonging to 19 taxa, was studied using the Mutual Ecogeographic Range and the Habitat Weighting Method. Throughout ~2600 years, the micromammal community's quick turnover reflected a shift from patchy forests and humid meadows to open, shrubbier grasslands. The Late Holocene Thermal Maximum's humid and mild climatic conditions underwent a cooling and aridification phase, coeval with the Iron Age Cold Epoch. These concluded in a slight temperature rising, coeval with the Roman Warm Period. Macromammals experienced a shift from wild populations to domestic herds. Therefore, this work discusses a broader context for this mammalian turnover from a human cultural perspectiveERC Consolidator Grant (SUBSILIENCE ref. 818299)Bilbao Port Authority (Autoridad Portuaria de Bilbao)Estabilización del sector occidental de la Cantera de Punta Lucero en el Puerto de Bilba

Instability mechanisms and evolution of a rocky cliff on the Atlantic coast of Spain

Predicting the response of rocky coasts to different erosional agents remains a great challenge at present. The episodic and discontinuous nature of the instability processes typical of hard bedrocks makes it difficult to make predictions based on observations over short research periods. This work aims to contribute to the understanding of the geomorphological evolution of rocky cliffs by means of a case study of a geologically complex cliff (developed on quartzite and slate) located on the Atlantic coast of Spain. The analysis of high-precision topographic models and orthophotographs, the use of geomatics techniques and geomorphological characterization have made it possible to define a model of the cliff behaviour. The results indicate that the structure of the bedrock determines the type of instability processes affecting the cliff and the morphology of the associated deposits. Lithology is the other main conditioning factor: while slate is easily eroded, quartzite offers greater strength and its detached blocks act as an effective natural defence element protecting the cliff and slowing down the coastal retreat. The evolution model established for this cliff explains the absence of retreat in the study period (2003–2022) and confirms the important role of local factors in cliff evolution.CRUE-CSICSpringer Nature"COSINES" Project, Call 2017 for RETOS Projects - Spanish Economy, Industry and Competitiveness Ministry-Ministerio de Economia, Industria y Competitividad (MINECO) CGL2017-83909-RSpanish Research AgencyAgencia Estatal de Investigacion (AEI)European Regional Development Found (FEDER)GEOCANCOSTA research group - Asturian Regional Government (Spain) GRUPIN-IDI-2018-184GEOCANTABRICAE research group - Asturian Regional Government (Spain) SV-PA-21-AYUD/2021/517

Nanocátalysts for oxygen removal from biomass derived biofuel

The use of bio-energy as a renewable alternative to fossil fuels is nowadays attracting more and more attention. Bio-fuel from biomass seems to be a potential energy substitute for fossil fuels since it is a renewable resource that could contribute to sustainable development and global environmental preservation and it appears to have significant economic potential. Liquid fuels can be obtained from fast pyrolysis of lignocellulosic biomass, where fast pyrolysis is a promising route because the process takes place at moderate temperatures, in absence of air and with a short hot vapor residence time. However, these liquid fuels have poor quality due to their low volatility, high viscosity, low heating value, a high oxygen content and poor chemical stability. This high oxygen is due to the presence of oxygen-containing compounds such as alcohols, aldehydes, ketones, furans and phenols. In this sense, catalytic hydrodeoxygenation (HDO) is one the most efficient processes to remove oxygen from these liquid fuels. In this context, the catalyst design is of upmost importance to achieve a high degree of deoxygenation, and bifunctional catalysts are required to achieve high degrees of activity. Noble metal and non-noble metal based catalysts will be evaluated in HDO of model molecules in order to get further insight about the important role of the active phase. Transition metal phosphides have shown excellent catalytic performances due to their good hydrogen transfer properties that diminishes the amount of metal exposed, avoiding, as much as possible, the deactivation, and modifies the electronic density of the catalyst leading to solids that favors the HDO. In addition these phosphides show bifunctional catalytic properties (metallic sites for hydrogenation and acid sites for cracking, methyl transfer reaction, dehydration and isomerization).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Weyl Estimates for spacelike hypersurfaces in de Sitter space

We study the isometric spacelike embedding problem in scaled de Sitter space, and obtain Weyl-type estimates and the corresponding closedness in the space of embeddings