Anders Svensson; Dorthe Dahl-Jensen; Jørgen Peder Steffensen; Thomas Blunier; Sune Olander Rasmussen; Bo Møllesøe Vinther; Paul Vallelonga; Emilie Capron; Vasileios Gkinis; Eliza Cook; +16 more
Anders Svensson; Dorthe Dahl-Jensen; Jørgen Peder Steffensen; Thomas Blunier; Sune Olander Rasmussen; Bo Møllesøe Vinther; Paul Vallelonga; Emilie Capron; Vasileios Gkinis; Eliza Cook; Helle Astrid Kjær; Raimund Muscheler; Sepp Kipfstuhl; Frank Wilhelms; Thomas F. Stocker; Hubertus Fischer; Florian Adolphi; Tobias Erhardt; Michael Sigl; Amaelle Landais; Frédéric Parrenin; Christo Buizert; Joseph R. McConnell; Mirko Severi; Robert Mulvaney; Matthias Bigler;
The last glacial period is characterized by a number of millennial climate events that have been identified in both Greenland and Antarctic ice cores and that are abrupt in Greenland climate records. The mechanisms governing this climate variability remain a puzzle that requires a precise synchronization of ice cores from the two hemispheres to be resolved. Previously, Greenland and Antarctic ice cores have been synchronized primarily via their common records of gas concentrations or isotopes from the trapped air and via cosmogenic isotopes measured on the ice. In this work, we apply ice core volcanic proxies and annual layer counting to identify large volcanic eruptions that have left a signature in both Greenland and Antarctica. Generally, no tephra is associated with those eruptions in the ice cores, so the source of the eruptions cannot be identified. Instead, we identify and match sequences of volcanic eruptions with bipolar distribution of sulfate, i.e. unique patterns of volcanic events separated by the same number of years at the two poles. Using this approach, we pinpoint 82 large bipolar volcanic eruptions throughout the second half of the last glacial period (12–60 ka). This improved ice core synchronization is applied to determine the bipolar phasing of abrupt climate change events at decadal-scale precision. In response to Greenland abrupt climatic transitions, we find a response in the Antarctic water isotope signals (δ18O and deuterium excess) that is both more immediate and more abrupt than that found with previous gas-based interpolar synchronizations, providing additional support for our volcanic framework. On average, the Antarctic bipolar seesaw climate response lags the midpoint of Greenland abrupt δ18O transitions by 122±24 years. The time difference between Antarctic signals in deuterium excess and δ18O, which likewise informs the time needed to propagate the signal as described by the theory of the bipolar seesaw but is less sensitive to synchronization errors, suggests an Antarctic δ18O lag behind Greenland of 152±37 years. These estimates are shorter than the 200 years suggested by earlier gas-based synchronizations. As before, we find variations in the timing and duration between the response at different sites and for different events suggesting an interaction of oceanic and atmospheric teleconnection patterns as well as internal climate variability.
We investigate the accuracy of how author names are reported in bibliographic records excerpted from four prominent sources: WoS, Scopus, PubMed, and CrossRef. We take as a case study 44,549 publications stored in the internal database of Sapienza University of Rome, one of the largest universities in Europe. While our results indicate generally good accuracy for all bibliographic data sources considered, we highlight a number of issues that undermine the accuracy for certain classes of author names, including compound names and names with diacritics, which are common features to Italian and other Western languages.
This paper presents the steps undertaken for building a word formation lexicon for Latin. The types of word formation rules are discussed and the semi-automatic procedure to pair their input and output lexical items is evaluated. An on-line graphical query system to access the lexicon is described as well. Questo articolo presenta le procedure di realizzazione di un lessico morfologico derivazionale per il latino. Sono descritti i tipi di regole di formazione di parola e viene valutata la qualità del sistema semi-automatico di individuazione delle parole in input e in output ad esse. Il sistema grafico d’interrogazione on-line dei dati è altresì presentato.