Groundwater and Porewater as Major Sources of Alkalinity to a Fringing Coral Reef Lagoon (Muri Lagoon, Cook Islands)

To better predict how ocean acidification will affect coral reefs, it is important to understand how biogeochemical cycles on reefs alter carbonate chemistry over various temporal and spatial scales. This study quantifies the contribution of shallow porewater exchange (as quantified from advective chamber incubations) and fresh groundwater discharge (as traced by 222Rn) to total alkalinity (TA) dynamics on a fringing coral reef lagoon along the southern Pacific island of Rarotonga over a tidal and diel cycle. Benthic alkalinity fluxes were affected by the advective circulation of water through permeable sediments, with net daily flux rates of carbonate alkalinity ranging from −1.55 to 7.76 mmol m−2 d−1, depending on the advection rate. Submarine groundwater discharge (SGD) was a source of TA to the lagoon, with the highest flux rates measured at low tide, and an average daily TA flux of 1080 mmol m−2 d−1 at the sampling site. Both sources of TA were important on a reef-wide basis, although SGD acted solely as a delivery mechanism of TA to the lagoon, while porewater advection was either a sink or source of TA dependent on the time of day. This study describes overlooked sources of TA to coral reef ecosystems that can potentially alter water column carbonate chemistry. We suggest that porewater and groundwater fluxes of TA should be taken into account in ocean acidification models in order to properly address changing carbonate chemistry within coral reef ecosystems

Drivers of pCO2 Variability in Two Contrasting Coral Reef Lagoons: The Influence of Submarine Groundwater Discharge

The impact of groundwater on pCO2 variability was assessed in two coral reef lagoons with distinct drivers of submarine groundwater discharge (SGD). Diel variability of pCO2 in the two ecosystems was explained by a combination of biological drivers and SGD inputs. In Rarotonga, a South Pacific volcanic island, 222Rn‐derived SGD was driven primarily by a steep terrestrial hydraulic gradient, and the water column was influenced by the high pCO2 (5501 µatm) of the fresh groundwater. In Heron Island, a Great Barrier Reef coral cay, SGD was dominated by seawater recirculation through the sediments (i.e., tidal pumping), and pCO2 was mainly impacted through the stimulation of biological processes. The Rarotonga water column had a higher average pCO2 (549 µatm) than Heron Island (471 µatm). However, pCO2 exhibited a greater diel range in Heron Island (778 µatm) than in Rarotonga (507 µatm). The Rarotonga water column received 29.0 ± 8.2 mmol free‐CO2 m−2 d−1 from SGD, while the Heron Island water column received 12.1 ± 4.2 mmol free‐CO2 m−2 d−1. Over the course of this study, both systems were sources of CO2 to the atmosphere with SGD‐derived free‐CO2 most likely contributing a large portion to the air‐sea CO2 flux. Studies measuring the carbon chemistry of coral reefs (e.g., metabolism and calcification rates) may need to consider the effects of groundwater inputs on water column carbonate chemistry. Local drivers of coral reef carbonate chemistry such as SGD may offer more approachable management solutions to mitigating the effects of ocean acidification on coral reefs

The effect of dissolved oxygen on N2O production by ammonia-oxidizing bacteria in an enriched nitrifying sludge

Dissolved oxygen (DO) is commonly recognized as an important factor influencing nitrous oxide (N2O) production by ammonia-oxidizing bacteria (AOB). However, it has been difficult to separate the true effect of DO from that of nitrite, as DO variation often affects nitrite accumulation. The effect of DO on N2O production by an enriched nitrifying sludge, consisting of both AOB and nitrite-oxidizing bacteria (NOB), was investigated in this study. Nitrite accumulation was minimised by augmenting nitrite oxidation through the addition of an enriched NOB sludge. It was demonstrated that the specific N2O production rate increased from 0 to 1.9±0.09 (n=3) mg N2O-N/hr/g VSS with an increase of DO concentration from 0 to 3.0mg O2/L, whereas N2O emission factor (the ratio between N2O nitrogen emitted and the ammonium nitrogen converted) decreased from 10.6±1.7% (n=3) at DO=0.2mg O2/L to 2.4±0.1% (n=3) at DO=3.0mg O2/L. The site preference measurements indicated that both the AOB denitrification and hydroxylamine (NH2OH) oxidation pathways contributed to N2O production, and DO had an important effect on the relative contributions of the two pathways. This finding is supported by analysis of the process data using an N2O model describing both pathways. As DO increased from 0.2 to 3.0mg O2/L, the contribution of AOB denitrification decreased from 92% - 95%-66% - 73%, accompanied by a corresponding increase in the contribution by the NH2OH oxidation pathway

European experience of the convergent atrial fibrillation procedure: Multicenter outcomes in consecutive patients

BackgroundThe objective of this collaborative, multicenter, European effort was to evaluate the outcomes of the convergent procedure for the treatment of persistent and long-standing persistent atrial fibrillation (AF) in consecutive patients at 4 European centers.MethodsOutcomes of consecutive patients, undergoing the convergent procedure at 4 European centers, were evaluated in this study. Epicardial ablation was performed before endocardial ablation. Convergent procedure outcomes were recorded by interrogation of implanted loop recorders or Holter monitors. Rhythm status and required interventions (antiarrhythmic drugs, cardioversions, and repeat ablations) were quantified 6 and 12 months after the procedure. Outcomes, monitoring type, and patient baseline characteristics were analyzed and reported.ResultsSeventy-three consecutive patients presenting with persistent AF (30.1%) or long-standing persistent AF (69.9%) underwent the convergent procedure between January 2010 and December 2011. At 6 months, 82% (56/68) were in sinus rhythm. At 12 months, 80% (53/66) were in sinus rhythm; single-procedure maintenance of sinus rhythm without postblanking period interventions was 76% (50/66); 52% (34/66) were in sinus rhythm and not receiving antiarrhythmic drugs.ConclusionsThis multicenter European collaborative effort demonstrated that the convergent procedure is a safe and efficacious treatment option for persistent and long-standing persistent AF

Charge transport in a single molecule transistor probed by scanning tunneling microscopy

We report on the scanning tunneling microscopy/spectroscopy (STM/STS) study of cobalt phthalocyanine (CoPc) molecules deposited onto a back-gated graphene device. We observe a clear gate voltage ( V g ) dependence of the energy position of the features originating from the molecular states. Based on the analysis of the energy shifts of the molecular features upon tuning  V g , we are able to determine the nature of the electronic states that lead to a gapped differential conductance. Our measurements show that capacitive couplings of comparable strengths exist between the CoPc molecule and the STM tip as well as between CoPc and graphene, thus facilitating electronic transport involving only unoccupied molecular states for both tunneling bias polarities. These findings provide novel information on the interaction between graphene and organic molecules and are of importance for further studies, which envisage the realization of single molecule transistors with non-metallic electrodes

Effectiveness of dupilumab treatment in 95 patients with atopic dermatitis: daily practice data

Background: Dupilumab is the first biologic registered for the treatment of moderate-to-severe atopic dermatitis (AD), and efficacy was shown in phase III clinical trials (primary outcome at week 16 was reached in 38% of patients). Currently, there are limited daily practice data available for dupilumab, especially when it is combined with systemic immunosuppressants. Objectives: To evaluate dupilumab treatment in daily practice in patients with AD. Methods: In this observational cohort study, we prospectively included all adult patients with AD who had been treated with dupilumab in two university hospitals in the Netherlands. Concomitant systemic immunosuppressive treatment was monitored. Physician-reported outcome measures and patient-reported outcome measures (PROMs) after ≥ 12 we

Drivers of pCO2 Variability in Two Contrasting Coral Reef Lagoons: The Influence of Submarine Groundwater Discharge

The impact of groundwater on pCO2 variability was assessed in two coral reef lagoons with distinct drivers of submarine groundwater discharge (SGD). Diel variability of pCO2 in the two ecosystems was explained by a combination of biological drivers and SGD inputs. In Rarotonga, a South Pacific volcanic island, 222Rn‐derived SGD was driven primarily by a steep terrestrial hydraulic gradient, and the water column was influenced by the high pCO2 (5501 µatm) of the fresh groundwater. In Heron Island, a Great Barrier Reef coral cay, SGD was dominated by seawater recirculation through the sediments (i.e., tidal pumping), and pCO2 was mainly impacted through the stimulation of biological processes. The Rarotonga water column had a higher average pCO2 (549 µatm) than Heron Island (471 µatm). However, pCO2 exhibited a greater diel range in Heron Island (778 µatm) than in Rarotonga (507 µatm). The Rarotonga water column received 29.0 ± 8.2 mmol free‐CO2 m−2 d−1 from SGD, while the Heron Island water column received 12.1 ± 4.2 mmol free‐CO2 m−2 d−1. Over the course of this study, both systems were sources of CO2 to the atmosphere with SGD‐derived free‐CO2 most likely contributing a large portion to the air‐sea CO2 flux. Studies measuring the carbon chemistry of coral reefs (e.g., metabolism and calcification rates) may need to consider the effects of groundwater inputs on water column carbonate chemistry. Local drivers of coral reef carbonate chemistry such as SGD may offer more approachable management solutions to mitigating the effects of ocean acidification on coral reefs

The genomes of two key bumblebee species with primitive eusocial organization

Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation

The neutron and its role in cosmology and particle physics

Experiments with cold and ultracold neutrons have reached a level of precision such that problems far beyond the scale of the present Standard Model of particle physics become accessible to experimental investigation. Due to the close links between particle physics and cosmology, these studies also permit a deep look into the very first instances of our universe. First addressed in this article, both in theory and experiment, is the problem of baryogenesis ... The question how baryogenesis could have happened is open to experimental tests, and it turns out that this problem can be curbed by the very stringent limits on an electric dipole moment of the neutron, a quantity that also has deep implications for particle physics. Then we discuss the recent spectacular observation of neutron quantization in the earth's gravitational field and of resonance transitions between such gravitational energy states. These measurements, together with new evaluations of neutron scattering data, set new constraints on deviations from Newton's gravitational law at the picometer scale. Such deviations are predicted in modern theories with extra-dimensions that propose unification of the Planck scale with the scale of the Standard Model ... Another main topic is the weak-interaction parameters in various fields of physics and astrophysics that must all be derived from measured neutron decay data. Up to now, about 10 different neutron decay observables have been measured, much more than needed in the electroweak Standard Model. This allows various precise tests for new physics beyond the Standard Model, competing with or surpassing similar tests at high-energy. The review ends with a discussion of neutron and nuclear data required in the synthesis of the elements during the "first three minutes" and later on in stellar nucleosynthesis.Comment: 91 pages, 30 figures, accepted by Reviews of Modern Physic