Population dynamics and demographic history of Eurasian collared lemmings.

BACKGROUND: Ancient DNA studies suggest that Late Pleistocene climatic changes had a significant effect on population dynamics in Arctic species. The Eurasian collared lemming (Dicrostonyx torquatus) is a keystone species in the Arctic ecosystem. Earlier studies have indicated that past climatic fluctuations were important drivers of past population dynamics in this species. RESULTS: Here, we analysed 59 ancient and 54 modern mitogenomes from across Eurasia, along with one modern nuclear genome. Our results suggest population growth and genetic diversification during the early Late Pleistocene, implying that collared lemmings may have experienced a genetic bottleneck during the warm Eemian interglacial. Furthermore, we find multiple temporally structured mitogenome clades during the Late Pleistocene, consistent with earlier results suggesting a dynamic late glacial population history. Finally, we identify a population in northeastern Siberia that maintained genetic diversity and a constant population size at the end of the Pleistocene, suggesting suitable conditions for collared lemmings in this region during the increasing temperatures associated with the onset of the Holocene. CONCLUSIONS: This study highlights an influence of past warming, in particular the Eemian interglacial, on the evolutionary history of the collared lemming, along with spatiotemporal population structuring throughout the Late Pleistocene

Ancient DNA of narrow-headed vole reveal common features of the Late Pleistocene population dynamics in cold-adapted small mammals

The narrow-headed vole, collared lemming and common vole were the most abundant small mammal species across the Eurasian Late Pleistocene steppe-tundra environment. Previous ancient DNA studies of the collared lemming and common vole have revealed dynamic population histories shaped by climatic fluctuations. To investigate the extent to which species with similar adaptations share common evolutionary histories, we generated a dataset comprised the mitochondrial genomes of 139 ancient and 6 modern narrow-headed voles from several sites across Europe and northwestern Asia covering approximately the last 100 thousand years (kyr). We inferred Bayesian time-aware phylogenies using 11 radiocarbon-dated samples to calibrate the molecular clock. Divergence of the main mtDNA lineages across the three species occurred during marine isotope stages (MIS) 7 and MIS 5, suggesting a common response of species adapted to open habitat during interglacials. We identified several time-structured mtDNA lineages in European narrow-headed vole, suggesting lineage turnover. The timing of some of these turnovers was synchronous across the three species, allowing us to identify the main drivers of the Late Pleistocene dynamics of steppe- and cold-adapted species.NWOVI.C.191.070Human Origin

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Influence of the growth method upon the phase transition of RbCdCl

Structural properties of two RbCdCl3 samples grown either from the melt or from aqueous solution are studied via X-ray diffraction over a closed temperature cycle between 20 °C and 300 °C. During cooling step (300 $^\circ{\rm C}\to 20$ °C), the crystal grown from the melt undergoes a phase transition at 110 °C that drives it from the cubic structure into a tetragonal structure that still persists at 20 °C. It undergoes exactly the reverse phase transition at the same temperature during the heating ($20~^\circ{\rm C}\to 300~^\circ$C) step that immediately follows. The other crystal grows from aqueous solution at 20 °C in an orthorhombic structure (i.e. not tetragonal as that of the crystal grown from the melt and cooled down to this temperature). During the heating ($20~^\circ{\rm C}\to 300~^\circ$C) step, it undergoes a direct orthorhombic-cubic phase transition at 240 °C (without passing through the tetragonal phase) whereas, during subsequent cooling (300 $^\circ{\rm C}\to 20$ °C), it does not exhibit the corresponding reverse phase transition but rather exhibits exactly the same cubic-tetragonal phase transition at 110 °C as the crystal grown from the melt. However, for both crystals, this tetragonal phase observed at room temperature is unstable and slowly converts into an orthorhombic phase over the course of time. Complementary Differential Scanning Calorimetry (D.S.C.) and Thermo Gravimetric Analysis (T.G.A.) measurements have been carried out over the range ($20\to 300$) °C in order to interpret diffraction experiments

WIKISemio : un outil de testing collaboratif de cartes : application au risque de piqûre de tiques

SAGEO 2019. Spatial Analysis and Geomatics, Clermont-Ferrand, FRA, 13-/11/2019 - 15/11/2019International audienceWeb2.0 tools (wiki, forum) have already been used successfully in geographic information systems (GIS) for collaborative editing of geo-referenced contents. On the other hand, no work was performed in collaborative testing of map semiology to date. To compensate for this lack, we propose WIKISemio, a web tool that integrates a WIKI.Les outils du Web2.0 (wiki, forum) ont été déjà utilisés avec succès dans les systèmes d'information géographique (SIG) pour l'édition collaborative de contenus géo-référencés. Par contre, aucun travail ne s'est intéressé au testing collaboratif de la sémiologie des cartes. Pour pallier ce manque, nous proposons WIKISemio, un outil web qui intègre un outil WIKI àun SIG pour permettre l'évaluation collaborative des variables sémiologiques de cartes

Geology, biostratigraphy and carbon isotope chemostratigraphy of the Paleogene fossil-bearing Dakhla sections, Southwestern Moroccan Sahara

International audienc

La storia a(l) tempo di Internet. Indagine sui siti italiani di storia contemporanea (2001-2003)

Il volume presenta i risultati di un'attenta ricognizione dei siti italiani di storia contemporanea operanti sul Web frutto della ricerca, sostenuta dalla Soprintendenza per i beni librari e documentari dell'IBC della Regione Emilia-Romagna, condotta da una solida equipe di studiosi tra il 2001 e il 2003. L'"opulenza informativa" inaugurata dalla rete e la carenza, d'altro canto, di chiavi di lettura per interpretare un sito e trattare le fonti elettroniche come una qualsiasi altra fonte informativa sono le premesse di questo lavoro, che intende affrontare criticamente il problema della storia (come di ogni altra forma di sapere) sottratta alla mediazione culturale degli operatori specializzati, storici, ma anche bibliotecari e archivisti. Ne deriva che il lettore non è più solo consumatore, ma anche produttore del testo. Il risvolto positivo è la crescente ampiezza dell'informazione stabilmente online ad opera di istituzioni pubbliche, archivi, giornali, centri di ricerca e associazioni, che agevola la ricerca storica e rende possibile nuovi tipi di indagine. La Rete può dunque promuovere pratiche originali di diffusione della conoscenza storica ma può anche appiattire quelle esistenti. Decisivo per il giudizio è l'insieme delle pratiche di comunicazione e di ricerca sul passato che si svolgono nel Web. Da qui questa ricerca, che si propone tre obiettivi: anzitutto proporre dei criteri orientativi per leggere criticamente i siti di storia; in secondo luogo offrire una rassegna ragionata di una parte consistente dei siti italiani di storia contemporanea; e infine trarre una prima e seppur parziale valutazione dello stato della storia italiana contemporanea in Rete. Il risultato è una classificazione dei siti in base ai soggetti produttori e ad argomenti chiave nella storiografia italiana contemporanea, e una schedatura che prende in esame per ogni sito identificazione, contenuti, struttura e linguaggi comunicativi e ne fornisce infine il giudizio complessivo dello specialista che lo ha esaminato. Un lavoro di grande importanza per iniziare la decodifica di un universo ricchissimo di informazioni e povero di strumenti interpretativi e critici quale è ancora il Web. Non a caso il volume esce nella collana ERBA della Soprintendenza per i beni librari e documentari dell'IBC della Regione Emilia-Romagna che ha promosso e sostenuto questo lavoro a riprova dell'attenzione, più volte testimoniata, verso il dibattito, quanto mai attuale al tempo di Internet, tra la difesa di principi e metodologie di alto livello tecnico-scientifico e l'opportunità della diffusione globale e immediata delle informazioni