Concentrations of levoglucosan, black carbon and ammonium from the RECAP ice core, East Greenland, for the last 5000 years in 20 years bins

This dataset presents the fire proxies levoglucosan, black carbon and ammonium measured in the RECAP ice core, in coastal East Greenland. The datasets cover a period of 5000 years and are averaged in 20 years bins. Levoglucosan has been determined using high performance liquid chromatography/negative ion electrospray ionization – tandem mass spectrometry (HPLC/(-)ESI-MS/MS). Black carbon has been measured using a BC analyzer connected to the Continuous Flow Analysis system. Ammonium (NH4+) has been measured by fluorescence within the Continuous Flow Analysis setup

A 5000 year-long record of levoglucosan, black carbon and ammonium from the RECAP ice core, East Greenland

This dataset presents the fire proxies levoglucosan, black carbon and ammonium measured in the RECAP ice core, in coastal East Greenland. The datasets cover a period of 5000 years and are averaged in 20 years bins. Raw concentrations of levoglucosan, black carbon and ammonium are also provided. Levoglucosan has been determined using high performance liquid chromatography/negative ion electrospray ionization – tandem mass spectrometry (HPLC/(-)ESI-MS/MS). Black carbon has been measured using a BC analyzer connected to the Continuous Flow Analysis system. Ammonium (NH4+) has been measured by fluorescence within the Continuous Flow Analysis setup

Ammonium (NH4+) raw data in the RECAP ice core, East Greenland, for the past 5000 years

This dataset presents the fire proxy ammonium (NH4+) measured in the RECAP ice core, in coastal East Greenland. The datasets cover a period of 5000 years. Ammonium (NH4+) has been measured by fluorescence within the Continuous Flow Analysis setup

Five thousand years of fire history in the high North Atlantic region:natural variability and ancient human forcing

Biomass burning influences global atmospheric chemistry by releasing greenhouse gases and climate-forcing aerosols. There is controversy about the magnitude and timing of Holocene changes in biomass burning emissions from millennial to centennial timescales and, in particular, about the possible impact of ancient civilizations. Here we present a 5 kyr record of fire activity proxies levoglucosan, black carbon, and ammonium measured in the RECAP (Renland ice cap) ice core, drilled in coastal eastern Greenland, and therefore affected by processes occurring in the high North Atlantic region. Levoglucosan and ammonium fluxes are high from 5 to 4.5 kyr BP (thousand years before 2000 CE) followed by an abrupt decline, possibly due to monotonic decline in Northern Hemisphere summer insolation. Levoglucosan and black carbon show an abrupt decline at 1.1 kyr BP, suggesting a decline in the wildfire regime in Iceland due to the extensive land clearing caused by Viking colonizers. All fire proxies reach a minimum during the second half of the last century, after which levoglucosan and ammonium fluxes increase again, in particular over the last 200 years. We find that the fire regime reconstructed from RECAP fluxes seems mainly related to climatic changes; however over the last mil-lennium human activities might have influenced wildfire frequency/occurrence substantially

Levoglucosan raw data in the RECAP ice core, East Greenland, for the past 5000 years

This dataset presents the fire proxy levoglucosan measured in the RECAP ice core, in coastal East Greenland. The datasets cover a period of 5000 years. Levoglucosan has been determined using high performance liquid chromatography/negative ion electrospray ionization – tandem mass spectrometry (HPLC/(-)ESI-MS/MS)

Levels and spatial distributions of levoglucosan and dissolved organic carbon in snowpits over the Tibetan Plateau glaciers

In this study, we collected 60 snowpit samples in nine glaciers from the northern to the southern Tibetan Plateau (TP), to study the levels and spatial distributions of levoglucosan and dissolved organic carbon (DOC). The lowest concentration of levoglucosan was found in the Yuzhufeng (YZF) glacier with a mean value of 0.24 ± 0.08 ng mLâ\u88\u92 1, while the highest concentration of levoglucosan was detected in the Gurenhekou (GRHK) glacier with a mean value of 11.72 ± 15.61 ng mLâ\u88\u92 1. However, the average DOC concentration in TP glaciers were comparable, without significant regional differences. The levoglucosan/DOC ratio ranged from 0.02 to 6.03% in the Tibetan Plateau glaciers. This ratios and the correlations between levoglucosan and DOC suggested that biomass burning products contributed only marginally to DOC levels in the TP glaciers. Moreover, the analysis of air mass backward trajectories suggested that levoglucosan and DOC in TP glaciers should be transported from the northwestern TP, internal TP, Central Asia, South and East Asia regions

Role of age and comorbidities in mortality of patients with infective endocarditis.

The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups: A total of 3120 patients with IE (1327  There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in th