Neoproterozoic Microfossils from the Margin of the East European Platform and the Search for a Biostratigraphic Model of Lower Ediacaran Rocks

A ca. 600 m thick siliciclastic succession in northern Russia contains abundant and diverse microfossils that document early to middle Ediacaran deposition along the northeastern margin of the East European Platform. The Vychegda Formation is poorly exposed but is well documented by a core drilled in the Timan trough region (Kel’tminskaya-1 borehole). Vychegda siliciclastics lie unconformably above Tonian to lower Cryogenian strata and below equivalents of the late Ediacaran Redkino succession that is widely distributed across the platform. The basal 10 m of the formation preserve acritarchs and fragments of problematic macrofossils known elsewhere only from pre-Sturtian successions. In contrast, the upper, nearly 400 m of the succession contains abundant and diverse large acanthomorphic acritarchs attributable to the Ediacaran Complex Acanthomorph Palynoflora (ECAP). This distinctive set of taxa is known elsewhere only from lower, but not lowermost, Ediacaran rocks. In between lies an additional assemblage of relatively simple filaments and stratigraphically long ranging sphaeromorphic acritarchs interpreted as early Ediacaran in age. Bearing in mind that knowledge of late Cryogenian (post-Strurtian/pre-Marinoan) microfossils is sparse, the Vychegda record is consistent with data from Australia and China which suggest that diverse ECAP microfossil assemblages appeared well into the Ediacaran Period. Accumulating paleontological observations underscore both the promise and challenges for the biostratigraphic characterization of the early Ediacaran Period.Organismic and Evolutionary Biolog

Ediacaran Microfossils from the Ura Formation, Baikal-Patom Uplift, Siberia: Taxonomy and Biostratigraphic Significance

Abundant and diverse microfossils from shales of the uppermost Ura Formation, central Siberia, document early to middle Ediacaran life along the southeastern margin of the Siberian Platform. The Ura Formation is well exposed in a series of sections in the Lena River basin but the best microfossil assemblages come from a locality along the Ura River. Here, the uppermost twenty meters of the formation contain diverse microfossils exceptionally well preserved as organic compressions. Fossils include nearly two dozen morphospecies of large acanthomorphic microfossils attributable to the Ediacaran Complex Acanthomorph Palynoflora (ECAP), a distinctive assemblage known elsewhere only from lower, but not lowermost, to middle Ediacaran rocks. Discovery of ECAP in strata previously considered Mesoproterozoic through Cryogenian confirms inferences from chemostratigraphy, dramatically changing stratigraphic interpretation of sedimentary successions and Proterozoic tectonics on the Siberian Platform. Systematic paleontology is reported for 36 taxa (five described informally) assigned to 23 genera of both eukaryotic and prokaryotic microfossils. One new genus and two new species are proposed: Ancorosphaeridium magnum n. gen. n. sp. and A. minor n. gen. n. sp.Organismic and Evolutionary Biolog

β-Polymorph of phenazepam: a powder study

The title compound [systematic name: 7-bromo-5-(2-chloro­phen­yl)-1H-1,4-benzodiazepin-2(3H)-one] (β-polymorph), C15H10BrClN2O, has been obtained via cryomodification of the known α-polymorph of phenazepam [Karapetyan et al. (1979 ▶). Bioorg. Khim. 5, 1684–1690]. In both polymorphs, the mol­ecules, which differ only in the dihedral angles between the aromatic rings [75.4 (2)° and 86.2 (3)° in the α- and β-polymorphs, respectively], are linked into centrosymmetric dimers via N—H⋯O hydrogen bonds. In the crystal structure of the β-polymorph, weak inter­molecular C—H⋯O hydrogen bonds further link these dimers into layers parallel to bc plane

Microfossils from the lower Mesoproterozoic Kaltasy Formation, East European Platform

Basinal shales of the lower Mesoproterozoic Kaltasy Formation, sampled from three boreholes drilled into the southeastern East European Platform, Russia, contain abundant and moderately well preserved microfossils. 34 distinct entities have been identified, most assigned to simple sphaeromorphic or small filamentous taxa found widely and characterized by long stratigraphic ranges. Ornamented microfossils found in coastal successions of other lower Mesoproterozoic basins are absent, but large filamentous microfossils interpreted as possible benthic photosynthetic eukaryotes are recorded, drawing comparisons to relatively deep water shales in Siberia. In overall aspect, the Kaltasy microfossils are consistent with other broadly coeval assemblages, but they highlight the importance of environment, as well as age, in determining the distributions of remains that record the early diversification of marine eukaryotes. Rectia magna is described as a new species.Organismic and Evolutionary Biolog

A multi-wavelength polarimetric study of the blazar CTA 102 during a Gamma-ray flare in 2012

We perform a multi-wavelength polarimetric study of the quasar CTA 102 during an extraordinarily bright $\gamma$-ray outburst detected by the {\it Fermi} Large Area Telescope in September-October 2012 when the source reached a flux of F$_{>100~\mathrm{MeV}} =5.2\pm0.4\times10^{-6}$ photons cm$^{-2}$ s$^{-1}$. At the same time the source displayed an unprecedented optical and NIR outburst. We study the evolution of the parsec scale jet with ultra-high angular resolution through a sequence of 80 total and polarized intensity Very Long Baseline Array images at 43 GHz, covering the observing period from June 2007 to June 2014. We find that the $\gamma$-ray outburst is coincident with flares at all the other frequencies and is related to the passage of a new superluminal knot through the radio core. The powerful $\gamma$-ray emission is associated with a change in direction of the jet, which became oriented more closely to our line of sight ($\theta\sim$1.2$^{\circ}$) during the ejection of the knot and the $\gamma$-ray outburst. During the flare, the optical polarized emission displays intra-day variability and a clear clockwise rotation of EVPAs, which we associate with the path followed by the knot as it moves along helical magnetic field lines, although a random walk of the EVPA caused by a turbulent magnetic field cannot be ruled out. We locate the $\gamma$-ray outburst a short distance downstream of the radio core, parsecs from the black hole. This suggests that synchrotron self-Compton scattering of near-infrared to ultraviolet photons is the probable mechanism for the $\gamma$-ray production.Comment: Accepted for publication in The Astrophysical Journa

Magnetic Dirac semimetal state of (Mn,Ge)Bi2_2Te4_4

For quantum electronics, the possibility to finely tune the properties of magnetic topological insulators (TIs) is a key issue. We studied solid solutions between two isostructural Z$_2$ TIs, magnetic MnBi$_2$Te$_4$ and nonmagnetic GeBi$_2$Te$_4$, with Z$_2$ invariants of 1;000 and 1;001, respectively. For high-quality, large mixed crystals of Ge$_x$Mn$_{1-x}$Bi$_2$Te$_4$, we observed linear x-dependent magnetic properties, composition-independent pairwise exchange interactions along with an easy magnetization axis. The bulk band gap gradually decreases to zero for $x$ from 0 to 0.4, before reopening for $x>0.6$, evidencing topological phase transitions (TPTs) between topologically nontrivial phases and the semimetal state. The TPTs are driven purely by the variation of orbital contributions. By tracing the x-dependent $6p$ contribution to the states near the fundamental gap, the effective spin-orbit coupling variation is extracted. As $x$ varies, the maximum of this contribution switches from the valence to the conduction band, thereby driving two TPTs. The gapless state observed at $x=0.42$ closely resembles a Dirac semimetal above the Neel temperature and shows a magnetic gap below, which is clearly visible in raw photoemission data. The observed behavior of the Ge$_x$Mn$_{1-x}$Bi$_2$Te$_4$ system thereby demonstrates an ability to precisely control topological and magnetic properties of TIs

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat