Análisis isotópicos (δ13C y δ18OCO3) en fósiles del Paleoceno basal de la Formación Tremp (Lleida): Implicaciones paleoambientales

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

A multi-proxy geochemical investigation of the early Paleocene (Danian) continental palaeoclimate at the Fontllonga-3 site (South Central Pyrenees, Spain)

Chronologically well constrained non-marine deposits across the Cretaceous–Tertiary boundary (KTb) are exceptionally rare. The Fontllonga section (Tremp Formation, South Central Pyrenees, Lleida, Spain) constitutes one of these rare global records. Stable isotope (δ18OCO3 and δ13C) analyses have been performed on the carbonate fraction of 29 samples from diverse skeletal micro-remains (charophyte gyrogonites, gastropod shells, ostracod valves and isolated skeletal remains of lepisosteids and pycnodonts) from the earliest Danian site, Fontllonga-3. A mean Ba/Ca water palaeotemperature of 28.0 ± 6.7 °C has been obtained from the ganoine of 25 lepisosteid scales. This mean palaeotemperature is comparable with the temperature tolerance range for extant relatives of fossil osteoglossiform fish found at Fontllonga-3, which require a temperature range of 24°–35 °C (mean annual temperature 27–30 °C) to survive. Using the temperature range provided by the Ba/Ca palaeothermometer (21.3–34.7 °C), it is possible to determine δ18Owater values from the isotopic content of charophyte gyrogonites, gastropod shells, ostracod valves and fish remains (mean δ18OCO3 = − 5.00 ‰, σ = 0.21). δ18Owater values of between − 4.01 and − 0.95‰ (VSMOW) are calculated, which, when combined with (La/Yb)N versus (La/Sm)N plots, are in good agreement with the sedimentary interpretation of the site as an estuarine environment. Based upon a comparison with modern day meteorical conditions these isotopic values are relatively high for subtropical freshwaters, suggesting a low precipitation rate (amount effect, high evaporation rate and/or long residence time). When combined with other isotopic, palaeobotanical and mineralogical studies carried out in the Pyrenean and Tethys realms this first geochemical study of an early Paleocene site is consistent with there being a subtropical seasonally dry climate in the South Central Pyrenees at this time

Analysis of the geochemical variability in lepisosteid scales from the Fontllonga-3 site (early Danian, Tremp Formation, South Central Pyrenees, Spain): Implications for palaeoenvironmental studies

Rare Earth Element (REE), Ba/Ca, Sr/Ca and δ18OPO4 analyses have been performed on the ganoine and isopedine of different types of isolated scales (anterior, middle, posterior flank scales and dorsal body margin scales) from juvenile lepisosteids from the Fontllonga-3 site (early Danian, Tremp Formation, South-Central Pyrenees, Spain) with the aim of detecting the most suitable kind of scale to be used in palaeoclimate studies. The REE flat-shape patterns obtained in lepisosteid scales from Fontllonga-3 are indicative of the absence of late stage diagenesis and recrystallization and have confirmed the identification of the palaeoenvironment where the Fontllonga-3 lepisosteids inhabited to be that of an estuary. The Ba/Ca palaeothermometer shows that posterior flank scales record on average 4.52 °C (ganoine) and 3.49 °C (isopedine) higher temperatures when compared to middle flank scales, which may be related to the fact that posterior flank scales grow preferentially during the warm season, whilst middle flank scales, which have the greatest number of layers of ganoine per unit of time and grow all year round, record a greater amplitude with respect to palaeoenvironmental and palaeoclimatic variations. Temperature values obtained from anterior flank scales follow a pattern similar to that showed by middle flank scales, whilst temperature values provided by dorsal scales resemble the pattern furnished by posterior flank scales. The same relationship between scale position and temperature but to a lesser degree (1.48 °C) is also evident in the calculated δ18OPO4 temperatures. The Ba/Ca palaeothermometer was applied by considering Ba/Ca ratios of the water for different types of environments and it has been found out that a ratio similar to that of marine waters yielded the best approximation to δ18OPO4 temperatures (29.82 ± 3.76 °C). The mean Ba/Ca temperature value obtained from the analysis of all the ganoine samples (26.96 ± 5.72 °C) is also consistent with the temperature of the water in which extant relatives of osteoglossiform fish, whose remains have been found in Fontllonga-3 along with lepisosteid remains, inhabit nowadays (24–40 °C, with mean values of 27 to 32 °C). The mean Ba/Ca temperature values furnished by the isopedine are lower than that obtained on the ganoine which may be due to minor diagenetic alteration. On account of these results, it is recommended that a distinction should be made between different types of scales as this could provide information concerning the summer growth temperature (posterior flank scales) as well as the annual temperature range (middle flank scales). Furthermore, it is recommended that ganoine be used in all studies as it appears to be the most resistant tissue in lepisosteid scales to diagenetic alteration

Influence of speed and heel-to-toe drop in running shoes for female recreational runners A cross-sectional study

In recent years, the popularity of running has boomed and the number of women runners has risen sharply. However, little research has been conducted into the running cycle as concerns female runners. The aim of this study is to analyse, in women runners, the relationships between spatiotemporal parameters in the running cycle, the heel drop in running shoes and a progressive increase in training speed, when running on a treadmill. Thirty-eight female runners were recruited from the Malaga University Athletics Club and Nerja Athletics Club. All were at least 18 years old, recreationally active (3–4 running sessions per week) and able to run 5kmin less than 25min. Their running performance on a treadmill was recorded and spatiotemporal parameters assessed using the OptoGait system. As the running speed increased (8–12–15km/h) the spatiotemporal parameters of the running cycle altered: the flight time increased (P<.001) and the contact time decreased (P=.05). Heel drop (4–12mm) was not significantly associated with any of the parameters (phase 1: P=.198; phase 2: P=.191; phase 3: P=.242). A progressive increase in training speed on a treadmill directly influences the spatiotemporal parameters of the running cycle in women runners

El uso de ChatGPT para la creación de actividades en el aula de chino como lengua extranjera: un estudio de caso de la competencia lectora

Cal incloure aquesta presentació a la col·lecció del grup .La irrupción de la inteligencia artificial (IA) y los modelos grandes de lenguaje (LLM), con ChatGPT como máximo exponente, nos obliga a repensar la enseñanza y el aprendizaje, en general, y el de lenguas extranjeras, en particular. Este potente modelo de lenguaje puede ser una herramienta valiosa para el diseño y desarrollo de actividades educativas en el aula de chino como lengua extranjera. En este contexto, nos preguntamos en qué medida los docentes podemos recurrir a ChatGPT para la creación de materiales docentes. Para abordar esta cuestión, en este estudio nos hemos marcado los siguientes objetivos: (1) evaluar la utilidad de ChatGPT en la generación de actividades dirigidas al desarrollo de la competencia lectora, y (2) determinar el procedimiento más eficaz en la creación de prompts para alcanzar dicho propósito. La metodología adoptada es un proceso exploratorio basado en el concepto de chain of thought (Sánchez-Gijón & Palenzuela-Badiola, 2023), mediante el cual se establece un diálogo continuo con el instrumento hasta lograr la actividad deseada. Los resultados preliminares indican las tipologías de actividades que se adecúan mejor a los objetivos didácticos y delinean el procedimiento óptimo para su creación y replicación. Este trabajo, más allá de sus hallazgos inmediatos, plantea importantes repercusiones e implicaciones didácticas, y sugiere un nuevo horizonte en la forma de concebir la enseñanza del chino y en cómo las tecnologías emergentes pueden ser integradas de manera efectiva en el aula

La multiplication de matériel de plantation de qualité pour améliorer l'état sanitaire et la productivité des cultures : pratiques clefs pour les bananiers et les bananiers plantain. Guide illustré

Available in English, French, Spanish and Arabic, on line and on CD-ROM, this illustrated guide summarizes the key practices for producing clean planting material of banana with a high yield potential for smallholders, depending on the pests and diseases which are present. The guide is also designed to contribute to better planning of the propagation of planting material for rural development and disaster relief projects. (Résumé d'auteur

Trackways Produced by Lungfish During Terrestrial Locomotion

Some primarily aquatic vertebrates make brief forays onto land, creating traces as they do. A lack of studies on aquatic trackmakers raises the possibility that such traces may be ignored or misidentified in the fossil record. Several terrestrial Actinopterygian and Sarcopterygian species have previously been proposed as possible models for ancestral tetrapod locomotion, despite extant fishes being quite distinct from Devonian fishes, both morphologically and phylogenetically. Although locomotion has been well-studied in some of these taxa, trackway production has not. We recorded terrestrial locomotion of a 35 cm African lungfish (Protopterus annectens; Dipnoi: Sarcopterygii) on compliant sediment. Terrestrial movement in the lungfish is accomplished by planting the head and then pivoting the trunk. Impressions are formed where the head impacts the substrate, while the body and fins produce few traces. The head leaves a series of alternating left-right impressions, where each impact can appear as two separate semi-circular impressions created by the upper and lower jaws, bearing some similarity to fossil traces interpreted as footprints. Further studies of trackways of extant terrestrial fishes are necessary to understand the behavioural repertoire that may be represented in the fossil track record