15 research outputs found

    Palaeoclimate inferred from ÎŽ18O and palaeobotanical indicators in freshwater tufa of Lake Äntu SinijĂ€rv, Estonia

    Get PDF
    We investigated a 3.75-m-long lacustrine sediment record from Lake Äntu SinijĂ€rv, northern Estonia, which has a modeled basal age >12,800 cal yr BP. Our multi-proxy approach focused on the stable oxygen isotope composition (ÎŽ18O) of freshwater tufa. Our new palaeoclimate information for the Eastern Baltic region, based on high-resolution ÎŽ18O data (219 samples), is supported by pollen and plant macrofossil data. Radiocarbon dates were used to develop a core chronology and estimate sedimentation rates. Freshwater tufa precipitation started ca. 10,700 cal yr BP, ca. 2,000 years later than suggested by previous studies on the same lake. Younger Dryas cooling is documented clearly in Lake Äntu SinijĂ€rv sediments by abrupt appearance of diagnostic pollen (Betula nana, Dryas octopetala), highest mineral matter content in sediments (up to 90 %) and low values of ÎŽ18O (less than −12 ‰). Globally recognized 9.3- and 8.2-ka cold events are weakly defined by negative shifts in ÎŽ18O values, to −11.3 and −11.7 ‰, respectively, and low concentrations of herb pollen and charcoal particles. The Holocene thermal maximum (HTM) is palaeobotanically well documented by the first appearance and establishment of nemoral thermophilous taxa and presence of water lilies requiring warm conditions. Isotope values show an increasing trend during the HTM, from −11.5 to −10.5 ‰. Relatively stable environmental conditions, represented by only a small-scale increase in ÎŽ18O (up to 1 ‰) and high pollen concentrations between 5,000 and 3,000 cal yr BP, were followed by a decrease in ÎŽ18O, reaching the most negative value (−12.7 ‰) recorded in the freshwater tufa ca. 900 cal yr BP

    Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

    Get PDF
    IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

    The Correlation Between Smoking, Snuff and MS

    No full text
    MS er en immunmediert, demyeliniserende sykdom i sentralnervesystemet. Selv om mye av etiologien fortsatt er uklar, antas det at bÄde genetiske og miljÞmessige faktorer bidrar i utviklingen av sykdommen. Oppgaven vÄr er en del av en pÄgÄende studie om risikofaktorer for MS som utfÞres ved Oslo Universitetssykehus, basert pÄ et spÞrreskjema hvor deltakerne blant annet ble spurt om nÄvÊrende og tidligere eksponering for rÞyking, passiv rÞyking og snusing. Til sammen ble 1374 personer inkludert i studien; 455 pasienter fra Oslo MS-register og 919 kontroller fra det norske beinmargsgiverregisteret. Dataene i pasientgruppen ble justert til Ä svare til tidspunktet for oppstart av sykdommen. Vi undersÞkte tobakk som risikofaktor for Ä utvikle MS ved Ä sammenligne aktive og passive rÞykevaner hos MS-pasienter med de i kontrollgruppen. Hedström et al. gjorde en lignende studie i Sverige i 2009, og vi har sammenlignet resultatene vÄre med deres data. Vi fant ingen signifikant Þkt risiko for utvikling av MS verken for snusere, passive rÞykere eller for dem som hadde sluttet Ä rÞyke, men en Þkt risiko for nÄvÊrende rÞykere. Mens risikoen sÄ ut til Ä vÊre Þkt ved et forbruk pÄ 1-5 pakkeÄr, fant vi ingen signifikant Þkt risiko for hÞyere tobakksforbruk. Feilkilder som seleksjonsbias, hukommelsesbias og tidsjustering av data i pasientgruppen kan ha pÄvirket resultatet

    Mindre gass, fÊrre eksplosjoner : Implementering av CO2-insufflasjon ved koloskopi ved gastroenterologisk avdeling pÄ Arendal sykehus

    Get PDF
    Problemstilling Det gjennomfÞres omtrent 50 000 koloskopier i Norge Ärlig. Tradisjonelt har man brukt romluft til Ä utvide tarmlumen, men de siste Ärene har det vist seg at insufflering med kun CO2 gir fÊrre pasientplager. Likevel utfÞres fortsatt koloskopiene ved mange norske sykehus med romluft. Vi kommer i denne oppgaven med et forslag til hvordan implementering av CO2-insufflering kan gjennomfÞres ved Arendal sykehus. Kunnskapsgrunnlag NÄr koloskopiene utfÞres med CO2-insufflering, opplever pasientene mindre smerter bÄde under og etter undersÞkelsen, og er mindre plaget av flatus, enn nÄr det benyttes romluft. Det er ikke vist noen signifikant forskjell i komplikasjoner. I 2012 ble det publisert EU-retningslinjer der bruk av CO2 anbefales som fÞrstevalg ved koloskopi. Dagens praksis og utfordringer Over halvparten av koloskopiene i Norge utfÞres med romluft, og ikke CO2. I Norge brukes det i tillegg mindre sedasjon og smertestillende under koloskopi enn i mange andre land. Det skulle tilsi at behovet for Ä bruke den minst smertefulle undersÞkelsesmetoden er enda stÞrre her i landet. Ved Arendal sykehus er det innfÞrt CO2-insufflering utelukkende ved det endoskopilaboratoriet som brukes i et screeningsprosjekt for cancer coli, mens de tre ordinÊre skopilaboratoriene benytter romluft. Utfordringene til implementering av CO2 er Ä overbevise de budsjettansvarlige om at det er nÞdvendig Ä bevilge midler til innkjÞp av utstyr, og Ä lÊre opp de ansatte om fordelene til CO2-insufflering, slik at de fÞlger nÞdvendige rutinene for at CO2 skal bli benyttet ved sÄ mange koloskopier som mulig. Prosess, ledelse og organisering Dette er et tofaset kvalitetsforbedringsprosjekt, der fase 1 er innfÞring av CO2-insufflering, og fase 2 er sikring av korrekt og hyppig bruk av de nye insufflatorene. Som utgangspunkt for gjennomfÞring av prosjektet, har vi brukt Langley og Nolans metode for kvalitetsforbedring med individuelle PUKK-sirkler for hver fase. Diskusjon og konklusjon Vi tror at en hovedutfordring ligger i Ä fÄ frem behovet for en slik kvalitetsforbedring blant de ansatte, bÄde ved laboratoriene og blant dem som har ansvar for bevilgning av midler. Det blir viktig Ä fÄ frem at plager under og etter koloskopi er et problem, selv om helsepersonellet ikke legger sÄ mye merke til det, og at disse plagene enkelt kan reduseres. Vi konkluderer med at dette prosjektet bÞr gjennomfÞres for Ä sikre norske pasienter et best mulig helsetilbud. Totalkostnaden er ikke stÞrre enn at fordelene med CO2-insufflering bÞr veie tyngre enn det Þkonomiske aspektet

    A very-high-energy component deep in the Îł-ray burst afterglow

    No full text
    Gamma-ray bursts (GRBs) are brief flashes of γ-rays and are considered to be the most energetic explosive phenomena in the Universe1. The emission from GRBs comprises a short (typically tens of seconds) and bright prompt emission, followed by a much longer afterglow phase. During the afterglow phase, the shocked outflow—produced by the interaction between the ejected matter and the circumburst medium—slows down, and a gradual decrease in brightness is observed2. GRBs typically emit most of their energy via γ-rays with energies in the kiloelectronvolt-to-megaelectronvolt range, but a few photons with energies of tens of gigaelectronvolts have been detected by space-based instruments3. However, the origins of such high-energy (above one gigaelectronvolt) photons and the presence of very-high-energy (more than 100 gigaelectronvolts) emission have remained elusive4. Here we report observations of very-high-energy emission in the bright GRB 180720B deep in the GRB afterglow—ten hours after the end of the prompt emission phase, when the X-ray flux had already decayed by four orders of magnitude. Two possible explanations exist for the observed radiation: inverse Compton emission and synchrotron emission of ultrarelativistic electrons. Our observations show that the energy fluxes in the X-ray and γ-ray range and their photon indices remain comparable to each other throughout the afterglow. This discovery places distinct constraints on the GRB environment for both emission mechanisms, with the inverse Compton explanation alleviating the particle energy requirements for the emission observed at late times. The late timing of this detection has consequences for the future observations of GRBs at the highest energies

    H.E.S.S. observations of the flaring gravitationally lensed galaxy PKS 1830–211

    No full text
    PKS 1830–211 is a known macrolensed quasar located at a redshift of zz = 2.5. Its high-energy gamma-ray emission has been detected with the Fermi-Large Area Telescope (LAT) instrument and evidence for lensing was obtained by several authors from its high-energy data. Observations of PKS 1830–211 were taken with the High Energy Stereoscopic System (H.E.S.S.) array of Imaging Atmospheric Cherenkov Telescopes in 2014 August, following a flare alert by the Fermi-LAT Collaboration. The H.E.S.S observations were aimed at detecting a gamma-ray flare delayed by 20–27 d from the alert flare, as expected from observations at other wavelengths. More than 12 h of good-quality data were taken with an analysis threshold of ∌67 GeV. The significance of a potential signal is computed as a function of the date and the average significance over the whole period. Data are compared to simultaneous observations by Fermi-LAT. No photon excess or significant signal is detected. An upper limit on PKS 1830–211 flux above 67 GeV is computed and compared to the extrapolation of the Fermi-LAT flare spectrum

    The starburst galaxy NGC 253 revisited by H.E.S.S. and Fermi-LAT

    No full text
    Context. NGC 253 is one of only two starburst galaxies found to emit Îł\gamma-rays from hundreds of MeV to multi-TeV energies. Accurate measurements of the very-high-energy (VHE; E > 100 GeV) and high-energy (HE; E > 60 MeV) spectra are crucial to study the underlying particle accelerators, probe the dominant emission mechanism(s) and to study cosmic-ray interaction and transport. Aims. The measurement of the VHE Îł\gamma-ray emission of NGC 253 published in 2012 by H.E.S.S. was limited by large systematic uncertainties. Here, the most up to date measurement of the Îł\gamma-ray spectrum of NGC 253 is investigated in both HE and VHE Îł\gamma-rays. Assuming a hadronic originof the Îł\gamma-ray emission, the measurement uncertainties are propagated into the interpretation of the accelerated particle population. Methods. The data of H.E.S.S. observations are reanalysed using an updated calibration and analysis chain. The improved Fermi−LAT analysis employs more than 8 yr of data processed using pass 8. The cosmic-ray particle population is evaluated from the combined HE–VHE Îł\gamma-ray spectrum using NAIMA in the optically thin case. Results. The VHE Îł\gamma-ray energy spectrum is best fit by a power-law distribution with a flux normalisation of (1.34 ± 0.14stat^{stat} ± 0.27sys^{sys})×10−13cm−2s−1TeV−110^{−13} cm^{−2} s^{−1} TeV^{−1} at 1 TeV – about 40% above, but compatible with the value obtained in Abramowski et al. (2012). The spectral index Γ=2.39±0.14stat±0.25sys\Gamma = 2.39 ± 0.14^{stat} ± 0.25^{sys} is slightly softer than but consistent with the previous measurement within systematic errors. In the Fermi energy range an integral flux of F(E > 60 MeV) = (1.56 ± 0.28stat^{stat} ± 0.15sys^{sys}) ×10−8cm−2s−110^{−8} cm^{−2} s^{−1} is obtained. At energies above ∌3 GeV the HE spectrum is consistent with a power-law ranging into the VHE part of the spectrum measured by H.E.S.S. with an overall spectral index Γ=2.22±0.06stat\Gamma = 2.22 ± 0.06^{stat}. Conclusions. Two scenarios for the starburst nucleus are tested, in which the gas in the starburst nucleus acts as either a thin or a thick target for hadronic cosmic rays accelerated by the individual sources in the nucleus. In these two models, the level to which NGC 253 acts as a calorimeter is estimated to a range of fcalf_{cal} = 0.1 to 1 while accounting for the measurement uncertainties. The presented spectrum is likely to remain the mostaccurate measurements until the Cherenkov Telescope Array (CTA) has collected a substantial set of data towards NGC 253
    corecore