Shallow-water hydrothermal venting linked to the Palaeocene–Eocene Thermal Maximum

The Palaeocene–Eocene Thermal Maximum (PETM) was a global warming event of 5–6 °C around 56 million years ago caused by input of carbon into the ocean and atmosphere. Hydrothermal venting of greenhouse gases produced in contact aureoles surrounding magmatic intrusions in the North Atlantic Igneous Province have been proposed to play a key role in the PETM carbon-cycle perturbation, but the precise timing, magnitude and climatic impact of such venting remains uncertain. Here we present seismic data and the results of a five-borehole transect sampling the crater of a hydrothermal vent complex in the Northeast Atlantic. Stable carbon isotope stratigraphy and dinoflagellate cyst biostratigraphy reveal a negative carbon isotope excursion coincident with the appearance of the index taxon Apectodinium augustum in the vent crater, firmly tying the infill to the PETM. The shape of the crater and stratified sediments suggests large-scale explosive gas release during the initial phase of vent formation followed by rapid, but largely undisturbed, diatomite-rich infill. Moreover, we show that these vents erupted in very shallow water across the North Atlantic Igneous Province, such that volatile emissions would have entered the atmosphere almost directly without oxidation to CO2 and at the onset of the PETM

Shallow-water hydrothermal venting linked to the Palaeocene–Eocene Thermal Maximum

The Palaeocene–Eocene Thermal Maximum (PETM) was a global warming event of 5–6 °C around 56 million years ago caused by input of carbon into the ocean and atmosphere. Hydrothermal venting of greenhouse gases produced in contact aureoles surrounding magmatic intrusions in the North Atlantic Igneous Province have been proposed to play a key role in the PETM carbon-cycle perturbation, but the precise timing, magnitude and climatic impact of such venting remains uncertain. Here we present seismic data and the results of a five-borehole transect sampling the crater of a hydrothermal vent complex in the Northeast Atlantic. Stable carbon isotope stratigraphy and dinoflagellate cyst biostratigraphy reveal a negative carbon isotope excursion coincident with the appearance of the index taxon Apectodinium augustum in the vent crater, firmly tying the infill to the PETM. The shape of the crater and stratified sediments suggests large-scale explosive gas release during the initial phase of vent formation followed by rapid, but largely undisturbed, diatomite-rich infill. Moreover, we show that these vents erupted in very shallow water across the North Atlantic Igneous Province, such that volatile emissions would have entered the atmosphere almost directly without oxidation to CO2 and at the onset of the PETM

Acute mountain sickness.

Acute mountain sickness (AMS) is a clinical syndrome occurring in otherwise healthy normal individuals who ascend rapidly to high altitude. Symptoms develop over a period ofa few hours or days. The usual symptoms include headache, anorexia, nausea, vomiting, lethargy, unsteadiness of gait, undue dyspnoea on moderate exertion and interrupted sleep. AMS is unrelated to physical fitness, sex or age except that young children over two years of age are unduly susceptible. One of the striking features ofAMS is the wide variation in individual susceptibility which is to some extent consistent. Some subjects never experience symptoms at any altitude while others have repeated attacks on ascending to quite modest altitudes. Rapid ascent to altitudes of 2500 to 3000m will produce symptoms in some subjects while after ascent over 23 days to 5000m most subjects will be affected, some to a marked degree. In general, the more rapid the ascent, the higher the altitude reached and the greater the physical exertion involved, the more severe AMS will be. Ifthe subjects stay at the altitude reached there is a tendency for acclimatization to occur and symptoms to remit over 1-7 days

Improved Turbulence Prediction in Turbomachinery Flows and The Effect on Three-Dimensional Boundary Layer Transition

International audienceFor numerical predicting turbomachinery flows a two-equation turbulence model in combination with a proper transition model to account for laminar boundary layers and their transition to turbulence is state of the art. is paper presents the ability of such a method (k-ω + γ-Re θ) for turbulence prediction and the effect on three-dimensional boundary layer behavior. For this purpose both applied models (turbulence and transition) are improved to be er account for turbulence length scale effects and three-dimensional transition prediction since these are the main deficiencies in predicting such kinds of flows. The improved numerical physical model is validated and tested on existing turbine cascades with detailed experimental data for the viscous regions and additionally on a low-speed axial compressor rig where wake-induced transition takes place

Epigenetics in Personality Disorders: Today's Insights

Objective: Epigenetic mechanisms have been described in several mental disorders, such as mood disorders, anxiety disorders and schizophrenia. However, less is known about the influence of epigenetic mechanisms with regard to personality disorders (PD). Therefore, we conducted a literature review on existing original data with regards to epigenetic peculiarities in connection with personality disorders. Methods: Systematic literature review using PRISMA guidelines. Search was performed via NCBI PubMed by keywords and their combinations. Used search terms included epigenetic, methylation, acetylation plus designations of specified personality traits and disorders according to DSM-IV. Results: Search yielded in total 345 publications, 257 thereof with psychiatric topic, 72 on personality disorder or traits, 43 of which were in humans and epigenetic, 23 thereof were original studies. Lastly, 23 original publications fulfilled the intended search criteria and were included. Those are 13 studies on gene methylation pattern with aggressive, antisocial and impulsive traits, 9 with borderline personality disorder (BPD), and 2 with antisocial personality disorder (ASPD). The results of these studies showed significant associations of PD with methylation aberrances in system-wide genes and suggest evidence for epigenetic processes in the development of personality traits and personality disorders. Environmental factors, of which childhood trauma showed a high impact, interfered with many neurofunctional genes. Methylation alterations in ASPD and BPD repeatedly affected HTR2A, HTR3A, NR3C1, and MAOA genes. Summary: Epigenetic studies in PD seem to be a useful approach to elucidate the interaction of co-working risk factors in the pathogenesis of personality traits and disorders. However, the complexity of pathogenesis leads to divergent results and impedes an explicit interpretation. Differing methylation patterns within the selected PD could indicate subgroups which would benefit from patient-oriented therapeutic adjustments. They might play a major role in the future design and observation of early therapeutic intervention and thus could help to prevent severe dysfunctional conduct or full-blown personality disorder in risk subjects

Perihematomal diffusion restriction as a common finding in large intracerebral hemorrhages in the hyperacute phase

<div><p>Purpose</p><p>There is growing evidence that a perihematomal area of restricted diffusion (PDR) exists in intraparenchymal hemorrhages (IPH) within 1 week of symptom onset (SO). Here, we study characteristics and the clinical impact of the PDR in patients with hyperacute (≤ 6 hours from SO) IPH by means of apparent diffusion coefficient (ADC).</p><p>Methods</p><p>This monocentric, retrospective study includes 83 patients with first-ever primary IPH from 09/2002-10/2015. 3D volumetric segmentation was performed for the IPH, PDR, and perihematomal edema (PHE) on fluid-attenuated inversion recovery, T2*/susceptibility weighted images, and ADC images.</p><p>Results</p><p>A PDR was seen in 56/83 patients (67.5%) presenting with hyperacute IPH. Multivariate logistic regression analysis revealed every 10-year increase of age (HR 1.929, 95% CI 1.047–3.552, <i>P</i> = .035) and male gender (HR 5.672, 95% CI 1.038–30.992, <i>P</i> = .045) as significant predictors of the presence of a PDR, but not IPH size, IPH location, nor National Institutes of Health Stroke Scale Score (NIHSS) at admission. We found no difference in NIHSS at discharge, hematoma removal, or mortality rate in PDR-positive patients. ADC values of the PDR show a step-wise normalization with increasing time from SO.</p><p>Conclusions</p><p>Occurrence of a PDR is a common finding in supratentorial hyperacute IPH, but shows no adverse short-term clinical impact. It may represent transient oligemic and metabolic changes.</p></div

Sequence parameters of FLAIR, DWI, and T2*/SWI of the different scanners.

<p>Sequence parameters of FLAIR, DWI, and T2*/SWI of the different scanners.</p

Multivariate regression analysis with gender, age, IPH location, time from symptom onset to MRI, NIHSS at admission, and log IPH volume as coefficients.

<p>Multivariate regression analysis with gender, age, IPH location, time from symptom onset to MRI, NIHSS at admission, and log IPH volume as coefficients.</p

Sequence parameters of FLAIR, DWI, and T2*/SWI of the different scanners.

<p>Sequence parameters of FLAIR, DWI, and T2*/SWI of the different scanners.</p

Baseline characteristics of all patients and perihematomal rim (PDR)-positive/PDR-negative patients.

<p>Data are given as median and interquartile range (in parenthesis).</p