Mineralogical Transformations and Soil Development in Shale Across a Latitudinal Climosequence

To investigate factors controlling soil formation, we established a climosequence as part of the Susquehanna-Shale Hills Critical Zone Observatory (SSHCZO) in central Pennsylvania, USA. Sites were located on organic matter-poor, iron-rich Silurian-aged shale in Wales, Pennsylvania, Virginia, Tennessee, Alabama, and Puerto Rico, although this last site is underlain by a younger shale. Across the climosequence, mean annual temperature (MAT) increases from 7 to 24°C and mean annual precipitation (MAP) ranges from 100 to 250 cm. Variations in soil characteristics along the climosequence, including depth, morphology, particle-size distribution, geochemistry, and bulk and clay mineralogy, were characterized to investigate the role of climate in controlling mineral transformations and soil formation. Overall, soil horizonation, depth, clay content, and chemical depletion increase with increasing temperature and precipitation, consistent with enhanced soil development and weathering processes in warmer and wetter locations. Secondary minerals are present at higher concentrations at the warmest sites of the climosequence; kaolinite increases from \u3c5% at northern sites in Wales and Pennsylvania to 30% in Puerto Rico. The deepest observed weathering reaction is plagioclase feldspar dissolution followed by the transformation of chlorite and illite to vermiculite and hydroxy-interlayered vermiculite. Plagioclase, although constituting \u3c12% of the initial shale mineralogy, may be the profile initiating reaction that begins shale bedrock transformation to weathered regolith. Weathering of the more abundant chlorite and illite minerals (∼70% of initial mineralogy), however, are more likely controlling regolith thickness. Climate appears to play a central role in driving soil formation and mineral weathering reactions across the climosequence

Early extracorporeal CPR for refractory out-of-hospital cardiac arrest

BACKGROUNDExtracorporeal cardiopulmonary resuscitation (CPR) restores perfusion and oxy-genation in a patient who does not have spontaneous circulation. The evidencewith regard to the effect of extracorporeal CPR on survival with a favorable neu-rologic outcome in refractory out-of-hospital cardiac arrest is inconclusive.METHODSIn this multicenter, randomized, controlled trial conducted in the Netherlands, weassigned patients with an out-of-hospital cardiac arrest to receive extracorporealCPR or conventional CPR (standard advanced cardiac life support). Eligible patientswere between 18 and 70 years of age, had received bystander CPR, had an initialventricular arrhythmia, and did not have a return of spontaneous circulationwithin 15 minutes after CPR had been initiated. The primary outcome was sur-vival with a favorable neurologic outcome, defined as a Cerebral PerformanceCategory score of 1 or 2 (range, 1 to 5, with higher scores indicating more severedisability) at 30 days. Analyses were performed on an intention-to-treat basis.RESULTSOf the 160 patients who underwent randomization, 70 were assigned to receiveextracorporeal CPR and 64 to receive conventional CPR; 26 patients who did notmeet the inclusion criteria at hospital admission were excluded. At 30 days, 14 pa-tients (20%) in the extracorporeal-CPR group were alive with a favorable neuro-logic outcome, as compared with 10 patients (16%) in the conventional-CPR group(odds ratio, 1.4; 95% confidence interval, 0.5 to 3.5; P = 0.52). The number of seri-ous adverse events per patient was similar in the two groups.CONCLUSIONSIn patients with refractory out-of-hospital cardiac arrest, extracorporeal CPR andconventional CPR had similar effects on survival with a favorable neurologic out-come. (Funded by the Netherlands Organization for Health Research and Develop-ment and Maquet Cardiopulmonary [Getinge]; INCEPTION ClinicalTrials.govnumber, NCT03101787.)Cardiolog

Search for high-energy neutrinos from gravitational wave event GW151226 and candidate LVT151012 with ANTARES and IceCube

The Advanced LIGO observatories detected gravitational waves from two binary black hole mergers during their first observation run (O1). We present a high-energy neutrino follow-up search for the second gravitational wave event, GW151226, as well as for gravitational wave candidate LVT151012. We find two and four neutrino candidates detected by IceCube, and one and zero detected by Antares, within ±500 s around the respective gravitational wave signals, consistent with the expected background rate. None of these neutrino candidates are found to be directionally coincident with GW151226 or LVT151012. We use nondetection to constrain isotropic-equivalent high-energy neutrino emission from GW151226, adopting the GW event's 3D localization, to less than 2×1051-2×1054 erg. © 2017 American Physical Society

Surface (sea floor) and near-surface (box cores) sediment mineralogy in Baffin Bay as a key to sediment provenance and ice sheet variations

To better understand the glacial history of the ice sheets surrounding Baffin Bay and to provide information on sediment pathways, samples from 82 seafloor grabs and core tops, and from seven box cores were subjected to quantitative X-ray diffraction weight percent (wt.%) analysis of the &lt;2 mm sediment fraction. The samples were collected between 67°N and 78°N, in water depths of 155 to 2375 m and were retrieved on cruises between A.D. 1964 and 2009. Grain size, magnetic characteristics, and colour reflectance data were also obtained on many of the samples. Twenty-one non-clay and 10 clay mineral species were identified; the average wt.% of the non-clay minerals was 70% and was dominated by quartz, various feldspars, and dolomite, whereas the dominant clay minerals were 1 M illite, biotite, and chlorite. Cluster analysis on principal component scores identified three main mineral groups, which also had strong associations with grain size and sediment magnetic properties. Box cores from the deep central basin (&gt;2000 m) all show an abrupt drop in calcite wt.% (post-5 cal ka BP?) following a major peak in detrital carbonate (mainly dolomite). This dolomite-rich detrital carbonate (DC) event in JR175BC06 is possibly coeval with the Younger Dryas cold event. Four possible glacial-sourced end members were employed in a compositional unmixing algorithm to gain insight into down core changes in sediment provenance at the deep central basin. Estimates of the rates of sediment accumulation in the central basin are only in the range of 2 to 4 cm/cal ka, surprisingly low given the glaciated nature of the surrounding land.</jats:p