1,721,128 research outputs found
A caccia di dinosauri. Scavare nel passato per scoprire il futuro del pianeta
No full textPerché mai, nell’epoca dell’esplosione della tecnologia, un giovane promettente dovrebbe fare il paleontologo? Quale interesse possono avere oggi ossa e tracce risalenti a milioni di anni fa?Sono domande che Federico Fanti, paleontologo e National Geographic Explorer, oltre che conduttore della trasmissione cult Il cacciatore di dinosauri, si è sentito porre molte volte. Ma la sua risposta è decisa e intrigante: scavare per capire come quelle incredibili creature – il 99,9% di tutte le forme di vita mai esistite! – abbiano affrontato i cambiamenti che la Terra ha subìto (ere glaciali, asteroidi, collisioni tra continenti, estinzioni di massa...) può aiutarci a comprendere perché il nostro Pianeta appaia attualmente com’è e quali mutazioni lo attendano se non trasformeremo presto le nostre abitudini.Ecco perché, sotto la minaccia drammatica del riscaldamento globale, è particolarmente interessante andare a caccia di dinosauri. Conscio di ciò, Fanti ci porta per mano nelle proprie missioni raccontate con ironia e spirito d’avventura, dal Canada alla Mongolia, dall’Inghilterra alla Tunisia, sempre in scenari remoti e affascinanti. Seguendo le sue indagini sul campo, impariamo così a osservare con l’occhio dello scienziato ambienti e stratificazioni e a ridimensionare la posizione della specie umana, una fra le tante sulla Terra. Il mondo non è nostro e la paleontologia – oggi più attuale che mai – ci induce non solo ad accettarlo ma anche a adeguarci di conseguenza
High evolutionary rates and the origin of the Rosso Ammonitico Veronese Formation (Middle-Upper Jurassic of Italy) reptiles
No full textThe fossil record of metriorhynchids and plesiosaurians from the Rosso Ammonitico Veronese Formation
(RAVFm, Middle–Upper Jurassic, Italy) is represented by elements collected between the eighteenth and
twentieth centuries. All the metriorhynchid material is referred to the genus Neptunidraco. The first RAVFm
plesiosaurian material was collected in the nineteenth century and referred to Plesiosaurus: elements
are here described and interpreted as a chimerical association of crocodylomorph and plesiosaurian
bones, providing the first co-occurrence of these clades in the RAVFm. The second plesiosaurian is the
associated skeleton that we refer to Anguanax zignoi gen. et sp. nov. Bayesian phylogenetic analysis
confirms the basal geosaurine affinities of Neptunidraco resulted by parsimony analysis. Using both
methods, Anguanax was recovered as a basal pliosaurid, sister group of the clade including Marmornectes
and Thalassophonea. Bayesian inference methods indicate that both Italian lineages diverged from other
known lineages between 176 and 171 Mya, also showing divergence rates significantly higher than any
other representative of their respective clades. We suggest a phase of rapid evolutionary adaptation to
deeper marine environments in the ancestors of the Rosso Ammonitico Veronese reptiles as a response to
the latest Liassic regressive regime in Northern Tethys
LC-MS/MS Analysis of AEA and 2-AG
No full text: LC-MS/MS is a powerful analytical technique that provides unequivocal identification and reliable quantification of the analytes, using Selected Reaction Monitoring or Multi Reaction Monitoring acquisition mode.Anandamide (N-arachidonoylethanolamine, AEA) and 2-Arachidonoylglycerol (2-AG) are the most abundant endocannabinoids (eCBs), which play a major role in a wide variety of physiological and pathological processes. Analysis of those compounds by means of LC-MS/MS allows the detection of very low concentrations in biological samples. Here, we describe how to determine AEA and 2-AG levels in tiny samples of tissues and plasma through LC-MS/MS, by using very quick and easy-to-perform extraction procedures, with reduced solvent consumption
LC-MS/MS based analytical strategies for the detection of lipid peroxidation products in biological matrices
No full textOxidative stress (OS) arises mainly from exposure to reactive oxygen species (ROS) such as superoxide anion, hydroxyl radical, and hydrogen peroxide. These molecules can cause significant damage to proteins, DNA, and lipids, leading to various diseases. Cells fight ROS with detoxifying enzymes; however, an imbalance can cause damage leading to ischemic conditions, heart disease progression, and neurological disorders such as Alzheimer's disease. Accurate assessment of OS levels is then crucial and oxidized lipidic products are considered relevant OS biomarkers. In fact, lipids are particularly prone to ROS attack, leading to lipid peroxidation, cell membrane damage, and toxic by-products affecting DNA, proteins, and low-density lipoproteins. This review reports on recent advances in LC-MS/MS approaches for OS lipidic biomarkers, focusing on overcoming analytical challenges. 3 different classes of biomarkers have been reported, malondialdehyde, isoprostanes and oxidised sterols. For each class, the main analytical challenges with a particular focus on derivatisation procedure, sensitivity, matrix effect, ionisation have been described and discussed. The recent advancements of the LC-MS-MS procedures move towards simpler approaches, reducing errors and improving the reliability of the measurement thus enabling a comprehensive and robust OS assessment
Three of North America's geoheritage sites and the lost 1863 exploration of Giovanni Capellini
No full textGeoparks and the valorization of sites with a strong geoheritage component is a new frontier fos sustainable tourism. A UNESCO special recognition was established in 2015, and much work has been undertaken in establishing sites in Europe and Asia, yet only five localities have been recognized iby UNESCO in North America. This paper discusses three sites relevant to geoheritage - Pulpit Rock in Massachusetts, Montmorency Falls in Quebec and Niagara Falls in New York and Ontario - which were visited in 1863 by the newly appointed professo of geology at Bologna University, Giovanni Capellini. During his four-month journeu across northeastern North America, he made sketches, took notes and collected more than 2000 specimens that together provide a depth of perspective on the importance of the geoheritage of the sites he visited. We chose these sites, among the many visited by Capellini, because Niagara Falls is now seeking UNESCO recognition, ant the othe two, though no longer fully accessible, remain important tourist sites and areas of geological interest
Tracing marine ingressions in continental deposits: the Bearpaw sea of west-central Alberta
No full textIntegrating palaeoecology and morphology in theropod diversity estimation: a case from the Aptian-Albian of Tunisia.
No full textCurrent knowledge of theropod dinosaurs of northern Africa and their diversity during the Early Cretaceous is deceptively fragmentary and commonly associated with inadequate stratigraphic and palaeoecological data. Thereby, confused taxonomic affinities of theropod remains, represented primarily by isolated teeth and fragmentary skeletal remains, resulted in speculations on the number of genera and their stratigraphic, geographic and ecological distribution. In this study, we introduce a discussion on the theropod diversity in the Aptian–Albian of southern Tunisia based on a multidisciplinary approach that combines detailed sedimentological analyses with canonical morphological and phylogenetic analyses. This study indicates the presence of three theropod clades, Spinosauridae, Abelisauroidea, and Carcharodontosauridae. Relevant for the identification of isolated specimens from the Saharan regions, carcharodontosaurids are not represented in the Aptian-Albian teeth record and thus relatively less abundant than spinosaurids and abelisauroids. Five ziphodont tooth morphotypes are referred to ontogenetic and/or positional differences among a single abelisauroid taxon. The other three teeth morphotypes most likely represent two distinct spinosaurid taxa. Finally, the calibrated stratigraphic distribution of discussed elements indicates a clear ecological partition between theropod taxa. In particular, abelisauroids and carcharodontosaurids are commonly found in inland, fluvial deposits together with titanosauriform and rebbachisaurid sauropods, and rare crocodilians. Conversely, spinosaurids are limited to estuarine to coastal deposits dominated by a rich and diverse crocodilian fauna along with actinopterygians and sarcopterygians, including large-sized coelacanthiforms
Evolution of the Western Interior Seaway in west-central Alberta (late Campanian, Canada): Implications for hydrocarbon exploration
Full text linkThis study presents the first integrated, high-resolution stratigraphic analysis of a large area of the Cretaceous
Western Interior Basin in Alberta (western Canada), providing new tools to discriminate sedimentary processes
and stratigraphic patterns of transgressive-regressive (T-R) cycles in correlative marine and non-marine domains.
We integrate gamma ray well-log analysis, measured sections, and paleontological data to determine sediment
accumulation and distribution during the second-order T-R cycle of the late Campanian Western Interior Seaway
over a previously unstudied area encompassing approximately 97,000 km2 of the Alberta foreland basin. The
Bearpaw Formation, historically regarded as the product of a single transgression, is shown to include two T-R
cycles, whose timing is constrained by new chronostratigraphic data that provides an unprecedented resolution
(~200 kyr) for the Cretaceous of western North America. Seven reference stratigraphic markers were mapped
across the study area from the marine deposits into the fluvial domains. 3D-modelled stratigraphic surfaces and
stratigraphic intervals resulted in isopach maps for consecutive systems tracts, allowing detailed interpretations
of their architecture and patterns of sediment accumulation. Our analysis provides paleogeographic maps for the
Western Interior Seaway, focusing primarily on the evidence of the paleo-coastlines during the documented
cycles. The distribution of fine-grained, primarily marine, sediments resulted in an effective seal for hydrocarbon
accumulation in the Belly River Group. Further oil migration upsection, within the Edmonton group, was prevented
by the occurrence of these sealing units. Data support the interpretation that eustasy provided the main
control on the evolution of the Western Interior Seaway during the late Campanian
LITHOBIOTOPES OF THE NEMEGT GOBI BASIN
Full text linkThree distinct but overlapping dinosaur-dominated faunas characterize the Upper Cretaceous Djadokhta, Baruungoyot, and Nemegt formations of the Nemegt Basin of Mongolia. Documented faunal differences cannot be explained easily by temporal succession, but can be understood in light of the physical processes controlling the life, death, and burial of taxa. The stratigraphy of the Gobi Desert region records tectonically driven geometries, clearly documenting preservational processes that differ from those acting in most other dinosaur-dominated beds worldwide. Small, asymmetric tectonic gra-bens were filled with Upper Cretaceous dinosaur-bearing deposits showing asymmetric distributions of facies, here termed lithobiotopes. The water-lain fluvial and alluvial plain facies of the Nemegt lithobiotope supported and preserved a fauna dominated by gigantic dinosaurs, but had a preservational bias against smaller animals. The Nemegt passed laterally into the interdune facies of the Baruungoyot lithobiotope, which represented a hostile environment for large species, but preserved smaller animals. This in turn passed laterally into the aeolianite facies of the Djadokhta lithobiotope, which is characterized by the remains of small dinosaurs and a rich fauna of other animals. The Nemegt Gobi Basin can be visualized as an oasis with a central pond supplied with water from ephemeral channels and surrounded by a semi-arid alluvial plain and dune fields. © 2021, Canadian Science Publishing. All rights reserved
Permian lobed Zoophycos as the product of the terrestrialization process: Behavioral innovation in the Tahkandit Limestone (Yukon River, Alaska, USA)
Full text linkPaleontological survey in the remote Yukon-Charley Rivers National Preserve in Alaska led to the discovery of
lobed Zoophycos from the lower Tahkandit Limestone (informally named Sandstone unit), an interval characterized
by grayish-green glauconitic sandstone and conglomerate of coastal origin. The studied Zoophycos consists
of a lobate skirt-like spreite bounded by a marginal tube. Smaller tongue-shaped lobes branch off from larger
parent lobes that share the same tongue-like shape. Sedimentological features, together with body fossils and
associated trace fossils (Planolites, Chondrites), indicate a shoreface habitat for the Zoophycos producer. This
shallow-marine environmental setting is in contrast with the deeper bathymetries in which lobed Zoophycos are
recovered in post-Palaeozoic times. The producer of the lobed Zoophycos of the Yukon River is interpreted as a
deposit-feeder that used sensory-driven, directed search for locating heterogeneously distributed trophic resources.
The Zoophycos producer filled its burrow with Coprolus-like fecal pellets, possibly complementing deposit
feeding with microbial gardening and/or food caching. Data presented here provide useful insight into the
morphological evolution and bathymetric distribution of Zoophycos, suggesting two ‘Golden Ages’ for lobed
Zoophycos: (1) Carboniferous–Permian and (2) Cretaceous–Neogene. This stratigraphic distribution supports the
important ecological role of major terrestrialization events, that are, the Palaeozoic expansion of land plants and
the Mesozoic expansion of angiosperms. The consequent increased input of nutrients to coastal areas was an
important contributor to declining trends in porewater oxygen concentrations. This phenomenon favored
adaptive traits to exploit nutrient-rich but oxygen-poor niches, among which the U-shaped marginal tube of
lobed Zoophycos was an efficient adaptation to bring oxygenated water into low-oxygen substrates
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