Unraveling North-African riverine and eolian contributions to central Mediterranean sediments during Holocene sapropel S1 formation

Hydroclimate variability has exerted a fundamental control on the alternating deposition of organic-lean marl and organic-rich sapropel sediments in the eastern Mediterranean Sea (EMS). However, the exact mechanisms regarding the freshwater sources and related changes are still debated. Here, Sr and Nd isotopes and high-resolution elemental data are used to constrain different riverine and eolian supplies to the central Mediterranean over the past 9.8 ka. The detrital sediments in core CP10BC, taken at the margin of the Libyan shelf in the southwestern Ionian Sea, can be described by a three-endmember mixing system based on Sr and Nd isotopic compositions. The same systematics can also be deduced from Ti and K compositional variability. The endmembers comprise: Saharan Dust, Aegean/Nile, and Libyan Soil, representing the eolian supply from North Africa, the riverine inputs from the Aegean/Nile areas, as well as the riverine and shelf-derived fluxes from the Libyan-Tunisian margin, respectively. For the sapropel S1 period in particular, we find important detrital supplies from fossil river/wadi systems along the Libyan-Tunisian margin, activated by intensified African monsoon precipitation. Combining the temporal profiles with the consistent variability observed in the 87Sr/86Sr–1000/Sr diagram, such Libyan contribution has been most prominent during the uppermost period of sapropel S1 in core CP10BC. This observation is in agreement with hydroclimate reconstructions of northwestern Libya. Comparison of the Sr-Nd isotope data between core CP10BC and four cores taken along a west–east transect throughout the EMS shows that this detrital supply originated mainly from western Libya/Tunisia, and was transported as far eastward as ∼25°E while being diluted by an increasing Nile contribution

Alpha-decay properties of superheavy elements Z=113−125Z=113-125 in the relativistic mean-field theory with vector self-coupling of ω\omega meson

We have investigated properties of $\alpha$-decay chains of recently produced superheavy elements Z=115 and Z=113 using the new Lagrangian model NL-SV1 with inclusion of the vector self-coupling of $\omega$ meson in the framework of the relativistic mean-field theory. It is shown that the experimentally observed alpha-decay energies and half-lives are reproduced well by this Lagrangian model. Further calculations for the heavier elements with Z=117-125 show that these nuclei are superdeformed with a prolate shape in the ground state. A superdeformed shell-closure at Z=118 lends an additional binding and an extra stability to nuclei in this region. Consequently, it is predicted that the corresponding $Q_\alpha$ values provide $\alpha$-decay half-lives for heavier superheavy nuclei within the experimentally feasible conditions. The results are compared with those of macroscopic-microscopic approaches. A perspective of the difference in shell effects amongst various approaches is presented and its consequences on superheavy nuclei are discussed.Comment: Revised version, 14 pages, 12 eps figures. To appear in PRC. Discussion on shell effects is shortened in the revised version. However, commonality of the role of shell effects in extreme superheavy regions and in the regions near the r-process path is maintained. Existence of a secondary superdeformed minimum for Z=113 is verified with another Lagrangian se

Regional Imprints of Changes in the Atlantic Meridional Overturning Circulation in the Eddy-rich Ocean Model VIKING20X

A hierarchy of global 1/4° (ORCA025) and Atlantic Ocean 1/20° nested (VIKING20X) ocean/sea-ice models is described. It is shown that the eddy-rich configurations performed in hindcasts of the past 50–60 years under CORE and JRA55-do atmospheric forcings realistically simulate the large-scale horizontal circulation, the distribution of the mesoscale, overflow and convective processes, and the representation of regional current systems in the North and South Atlantic. The representation, and in particular the long-term temporal evolution, of the Atlantic Meridional Overturning Circulation (AMOC) strongly depends on numerical choices for the application of freshwater fluxes. The interannual variability of the AMOC instead is highly correlated among the model experiments and also with observations, including the 2010 minimum observed by RAPID at 26.5° N pointing at a dominant role of the forcing. Regional observations in western boundary current systems at 53° N, 26.5° N and 11° S are explored in respect to their ability to represent the AMOC and to monitor the temporal evolution of the AMOC. Apart from the basin-scale measurements at 26.5° N, it is shown that in particular the outflow of North Atlantic Deepwater at 53° N is a good indicator of the subpolar AMOC trend during the recent decades, if the latter is provided in density coordinates. The good reproduction of observed AMOC and WBC trends in the most reasonable simulations indicate that the eddy-rich VIKING20X is capable in representing realistic forcing-related and ocean-intrinsic trends

Controls on erosion patterns and sediment transport in a monsoonal, tectonically quiescent drainage, Song Gianh, central Vietnam

The Song Gianh is a small-sized (~3500 km2), monsoon-dominated river in northern central Vietnam that can be used to understand how topography and climate control continental erosion. We present major element concentrations, together with Sr and Nd isotopic compositions, of siliciclastic bulk sediments to define sediment provenance and chemical weathering intensity. These data indicate preferential sediment generation in the steep, wetter upper reaches of the Song Gianh. In contrast, detrital zircon U-Pb ages argue for significant flux from the drier, northern Rao Tro tributary. We propose that this mismatch represents disequilibrium in basin erosion patterns driven by changing monsoon strength and the onset of agriculture across the region. Detrital apatite fission track and 10Be data from modern sediment support slowing of regional bedrock exhumation rates through the Cenozoic. If the Song Gianh is representative of coastal Vietnam then the coastal mountains may have produced around 132 000–158 000 km3 of the sediment now preserved in the Song Hong-Yinggehai Basin (17–21 of the total), the primary depocenter of the Red River. This flux does not negate the need for drainage capture in the Red River to explain the large Cenozoic sediment volumes in that basin but does partly account for the discrepancy between preserved and eroded sediment volumes. OSL ages from terraces cluster in the Early Holocene (7.4–8.5 ka), Pre-Industrial (550–320 year BP) and in the recent past (ca. 150 year BP). The older terraces reflect high sediment production driven by a strong monsoon, whereas the younger are the product of anthropogenic impact on the landscape caused by farming. Modern river sediment is consistently more weathered than terrace sediment consistent with reworking of old weathered soils by agricultural disruption

The Randomized Shortened Dental Arch Study: Tooth Loss

The evidence concerning the management of shortened dental arch (SDA) cases is sparse. This multi-center study was aimed at generating data on outcomes and survival rates for two common treatments, removable dental prostheses (RDP) for molar replacement or no replacement (SDA). The hypothesis was that the treatments lead to different incidences of tooth loss. We included 215 patients with complete molar loss in one jaw. Molars were either replaced by RDP or not replaced, according to the SDA concept. First tooth loss after treatment was the primary outcome measure. This event occurred in 13 patients in the RDP group and nine patients in the SDA group. The respective Kaplan-Meier survival rates at 38 months were 0.83 (95% CI: 0.74-0.91) in the RDP group and 0.86 (95% CI: 0.78-0.95) in the SDA group, the difference being non-significant

Recruitment collapse and population structure of the European eel shaped by local ocean current dynamics

Highlights: • We combine high-resolution ocean models with population genetics • Variation in wind-driven ocean currents mediates the collapse of A. anguilla • Female eels are philopatric within the Sargasso Sea, while males maintain gene flow • We present first evidence of the role of ocean currents in shaping species’ evolution Summary: Worldwide, exploited marine fish stocks are under threat of collapse [1]. Although the drivers behind such collapses are diverse, it is becoming evident that failure to consider evolutionary processes in fisheries management can have drastic consequences on a species’ long-term viability [2]. The European eel (Anguilla anguilla; Linnaeus, 1758) is no exception: not only does the steep decline in recruitment observed in the 1980s [ 3 and 4] remain largely unexplained, the punctual detection of genetic structure also raises questions regarding the existence of a single panmictic population [ 5, 6 and 7]. With its extended Transatlantic dispersal, pinpointing the role of ocean dynamics is crucial to understand both the population structure and the widespread decline of this species. Hence, we combined dispersal simulations using a half century of high-resolution ocean model data with population genetics tools. We show that regional atmospherically driven ocean current variations in the Sargasso Sea were the major driver of the onset of the sharp decline in eel recruitment in the beginning of the 1980s. The simulations combined with genotyping of natural coastal eel populations furthermore suggest that unexpected evidence of coastal genetic differentiation is consistent with cryptic female philopatric behavior within the Sargasso Sea. Such results demonstrate the key constraint of the variable oceanic environment on the European eel population

RNase1 as a potential mediator of remote ischaemic preconditioning for cardioprotection

© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. OBJECTIVES: Remote ischaemic preconditioning (RIPC) is a non-invasive and virtually cost-free strategy for protecting the heart against acute ischaemia-reperfusion injury (IRI). We have recently shown that the inhibition of extracellular RNA (eRNA) using non-toxic RNase1 protected the heart against acute IRI, reduced myocardial infarct (MI) size and preserved left ventricular systolic function in rodent animal MI models. Based on this previous work in animals, the role of the eRNA/RNase1 system in cardiac RIPC in humans should be defined. METHODS: Fourteen patients underwent cardiac surgery without RIPC; from each patient, six separate 5 ml blood specimens from radial artery and two blood specimens from coronary sinus at different time points during heart surgery were taken. Six healthy donors received RIPC (4 × 5 min upper limb ischaemia); blood parameters were quantified before and after RIPC. Twelve patients underwent cardiac surgery of which 6 received RIPC, whereas the remaining 6 were exposed to sham procedure. Circulating eRNA was quantified in plasma from arterial and coronary sinus blood obtained from patients undergoing cardiac by standard procedures. Tumour necrosis factor-α (TNF-α) production by heart tissue was assessed by enzyme-linked immuno-sorbent assay; RNase activity was quantified by an enzymatic assay. RESULTS: Before surgery, eRNA levels were similar in both groups (14 ± 6 vs 13 ± 5 ng/ml; P = 0.9967). In patients without RIPC, arterial eRNA levels rose during surgery (87 ± 12 ng/ml) and peaked after (127 ± 11 ng/ml) aortic declamping; accordingly, eRNA levels in coronary sinus blood were significantly higher (206 ± 32 ng/ml; P = 0.0129) than that in radial artery. Moreover, significant elevation of TNF-α (36 ± 6 ng/ml; P = 0.0059) particularly in coronary sinus blood after opening of the aortic clamping was observed. Interestingly, applying a RIPC protocol significantly increased levels of plasma endogenous vascular RNase1 by >7-fold, and the levels of arterial (31 ± 7 ng/ml; P = 0.0024) and coronary sinus (37 ± 9 ng/ml; P < 0.0001) circulating eRNA, as well as circulating TNF-α (20 ± 4 ng/ml; P = 0.0050) levels were significantly reduced. CONCLUSIONS: Upon RIPC, the level of cardioprotective RNase1 increased, while the concentration of damaging eRNA and TNF-α decreased. The present findings imply a significant contribution of the RIPC-dependent (endothelial) RNase1 for improving the outcome of cardiac surgery. However, the exact mechanism of RNase1-induced cardioprotection still remains to be explored

Regional Patterns of Sea Level Change Related to Interannual Variability and Multidecadal Trends in the Atlantic Meridional Overturning Circulation

Some studies of ocean climate model experiments suggest that regional changes in dynamic sea level could provide a valuable indicator of trends in the strength of the Atlantic meridional overturning circulation (MOC). This paper describes the use of a sequence of global ocean–ice model experiments to show that the diagnosed patterns of sea surface height (SSH) anomalies associated with changes in the MOC in the North Atlantic (NA) depend critically on the time scales of interest. Model hindcast simulations for 1958–2004 reproduce the observed pattern of SSH variability with extrema occurring along the Gulf Stream (GS) and in the subpolar gyre (SPG), but they also show that the pattern is primarily related to the wind-driven variability of MOC and gyre circulation on interannual time scales; it is reflected also in the leading EOF of SSH variability over the NA Ocean, as described in previous studies. The pattern, however, is not useful as a “fingerprint” of longer-term changes in the MOC: as shown with a companion experiment, a multidecadal, gradual decline in the MOC [of 5 Sv (1 Sv ≡ 106 m3 s−1) over 5 decades] induces a much broader, basin-scale SSH rise over the mid-to-high-latitude NA, with amplitudes of 20 cm. The detectability of such a trend is low along the GS since low-frequency SSH changes are effectively masked here by strong variability on shorter time scales. More favorable signal-to-noise ratios are found in the SPG and the eastern NA, where a MOC trend of 0.1 Sv yr−1 would leave a significant imprint in SSH already after about 20 years

Spatial and temporal patterns of pore water chemistry in the inter-tidal zone of a high energy beach

Submarine groundwater discharge (SGD) is a ubiquitous source of meteoric fresh groundwater and recirculating seawater to the coastal ocean. Due to the hidden distribution of SGD, as well as the hydraulic- and stratigraphy-driven spatial and temporal heterogeneities, one of the biggest challenges to date is the correct assessment of SGD-driven constituent fluxes. Here, we present results from a 3-dimensional seasonal sampling campaign of a shallow subterranean estuary in a high-energy, meso-tidal beach, Spiekeroog Island, Northern Germany. We determined beach topography and analyzed physico-chemical and biogeochemical parameters such as salinity, temperature, dissolved oxygen, Fe(II) and dissolved organic matter fluorescence (FDOM). Overall, the highest gradients in pore water chemistry were found in the cross-shore direction. In particular, a strong physico-chemical differentiation between the tidal high water and low water line was found and reflected relatively stable in- and exfiltrating conditions in these areas. Contrastingly, in between, the pore water compositions in the existing foreshore ridge and runnel system were very heterogeneous on a spatial and temporal scale. The reasons for this observation may be the strong morphological changes that occur throughout the entire year, which affect the exact locations and heights of the ridge and runnel structures and associated flow paths. Further, seasonal changes in temperature and inland hydraulic head, and the associated effect on microbial mediated redox reactions likely overprint these patterns. In the long-shore direction the pore water chemistry varied less than the along the cross-shore direction. Variation in long-shore direction was probably occurring due to topography changes of the ridge-runnel structure and a physical heterogeneity of the sediment, which produced non-uniform groundwater flow conditions. We conclude that on meso-tidal high energy beaches, the rapidly changing beach morphology produces zones with different approximations to steady-state conditions. Therefore, we suggest that zone-specific endmember sampling is the optimal strategy to reduce uncertainties of SGD-driven constituent fluxes