Burial Recording Mines: a valid technique to study bedform migration and storm impact above the sea-floor

Initially, Burial Recording Mines (BRMs) were used to understand the sea mine burial. It was a technique predominantly related to military purpose. The first experiment was made 1974. Now a day, it is used as a valid tool for marine science. This methodology gives the rare opportunity to observe and analyze the processes acting on the seafloor directly, making the estimation closer to the reality. During MARIDIV, we present the results of 3 months experiment using burial recording mines. The experiment was performed between September 2008 and January 2009. The Wandelaar region on the Belgian Continental Shelf was chosen as suitable test area. 10,000 measurements of the sediment height around the cylindrical object were recorded, each one of those every 15 minutes. The dataset collected, together with sediment characterization and hydrological and meteorological information, allowed the understanding of the bedform migration. During the experiment, 2 storms passed the test area, in October and November 2008. Using Burial Recording Mines gave the rare opportunity to observe and analyze the storm impact directly on the sea-floor. Processes during and after the second storm will be revealed

The impact of in-season national team soccer play on injury and player availability in a professional club

This study investigated the impact of in-season national team duty on injury rates and player availability in a professional soccer club. Time-loss injuries and exposure time during club and national team duties were recorded prospectively over 5 seasons (2009–2014). A time-loss injury was sustained by 37.7% of squad members participating in national duty, all injuries occurring in match-play. The incidence (per 1000 h exposure) for national team player match-play injuries did not differ (P = 0.608) to that for all players in club competitions: 48.0 (95% CI 20.9–75.5) vs. 41.9 (95% CI 36.5–47.4), incidence rate ratio = 1.2 (CI: 0.8–2.4). The majority (58%) of national team injuries resulted in a layoff ≤1 week. Of all working days lost to injury generally, 5.2% were lost through injury on national duty. Injury incidence in the week following national duty was comparable (P = 0.818) in players participating or not: 7.8 (95% CI 3.6–12.0) vs. 7.1 (95% CI: 4.6–9.6), incidence rate ratio = 1.1 (CI: 0.7–2.7). While approximately 40% of participating players incurred a time-loss injury on national duty, no training injuries were sustained and injuries made up a negligible part of overall club working days lost to injury. Following duty, players had a similar injury risk to peers without national obligations

Search for anisotropic effects of hcp solid helium on optical lines of cesium impurities

The anisotropic effect of a hcp 4He solid matrix on cesium atoms has been proposed as a tool to reveal the parity violating anapole moment of its nucleus. It should also result in splitting the D2 optical excitation line in a way depending on the light polarization. An experimental investigation has been set up using oriented hcp helium crystals in which cesium metal grains are embedded. Atoms are created by laser sputtering from this grains. Optical absorption spectra of the D2 line have been recorded in the temperature range of 1.0 to 1.4 K at liquid/solid coexistence pressure by monitoring the fluorescence on the D2 line at 950 nm. No significant effect of the light polarization has been found, suggesting a statistically isotropic disordered solid environment for the cesium atoms.Comment: The original publication will be available at http://www.springerlink.co

Elevated CO₂ affects embryonic development and larval phototaxis in a temperate marine fish

As an effect of anthropogenic CO2 emissions, the chemistry of the world's oceans is changing. Understanding how this will affect marine organisms and ecosystems are critical in predicting the impacts of this ongoing ocean acidification. Work on coral reef fishes has revealed dramatic effects of elevated oceanic CO2 on sensory responses and behavior. Such effects may be widespread but have almost exclusively been tested on tropical reef fishes. Here we test the effects elevated CO2 has on the reproduction and early life history stages of a temperate coastal goby with paternal care by allowing goby pairs to reproduce naturally in an aquarium with either elevated (ca 1400 μatm) CO2 or control seawater (ca 370 μatm CO2). Elevated CO2 did not affect the occurrence of spawning nor clutch size, but increased embryonic abnormalities and egg loss. Moreover, we found that elevated CO2 significantly affected the phototactic response of newly hatched larvae. Phototaxis is a vision-related fundamental behavior of many marine fishes, but has never before been tested in the context of ocean acidification. Our findings suggest that ocean acidification affects embryonic development and sensory responses in temperate fishes, with potentially important implications for fish recruitment

Maintenance or change? Examining the reinforcing spiral between social media news use and populist attitudes

Citizens around the world increasingly express support for populism. Here, we apply the reinforcing spirals model to examine whether, and how, social media news use shapes populist attitudes over time. Specifically, we assess if using social media as a news source serves to maintain existing populist attitudes or facilitates a shift in attitudes to a more extreme position. A cross-sectional survey (N = 195) highlighted a positive correlation between social media news use and populist attitudes. A four-wave longitudinal survey (N = 386) further showed that this relationship reflects media and selection effects. Over a period of three months, more frequent social media news use predicted stronger populist attitudes at subsequent measuring points. In addition, higher levels of populist attitudes were related to more frequent social media news consumption in the following waves. However, the frequency of social media news use did not change over time and populist attitudes did not become stronger during the study period. Taken together, the findings indicate that social media news use contributed to the maintenance of populist attitudes at a stable level. There is no evidence to suggest social media news use predicted more extreme populist attitudes. We discuss these results with respect to the (potentially continued) rise of populism; we also critically reflect on the phenomenon of attitude polarization online. 1

Theory of semiconductor quantum-wire based single- and two-qubit gates

A GaAs/AlGaAs based two-qubit quantum device that allows the controlled generation and straightforward detection of entanglement by measuring a stationary current-voltage characteristic is proposed. We have developed a two-particle Green's function method of open systems and calculate the properties of three-dimensional interacting entangled systems non-perturbatively. We present concrete device designs and detailed, charge self-consistent predictions. One of the qubits is an all-electric Mach-Zehnder interferometer that consists of two electrostatically defined quantum wires with coupling windows, whereas the second qubit is an electrostatically defined double quantum dot located in a second two-dimensional electron gas beneath the quantum wires. We find that the entanglement of the device can be controlled externally by tuning the tunneling coupling between the two quantum dots.Comment: 16 pages, 13 figures, RevTex4 two-column format, to appear in Phys. Rev.

CO2 induced seawater acidification impacts sea urchin larval development I: Elevated metabolic rates decrease scope for growth and induce developmental delay

Anthropogenic CO(2) emissions are acidifying the world's oceans. A growing body of evidence is showing that ocean acidification impacts growth and developmental rates of marine invertebrates. Here we test the impact of elevated seawater pCO(2) (129Pa, 1271 atm) on early development, larval metabolic and feeding rates in a marine model organism, the sea urchin Strongylocentrotus purpuratus. Growth and development was assessed by measuring total body length, body rod length, postoral rod length and posterolateral rod length. Comparing these parameters between treatments suggests that larvae suffer from a developmental delay (by ca. 8%) rather than from the previously postulated reductions in size at comparable developmental stages. Further, we found maximum increases in respiration rates of +100% under elevated pCO(2), while body length corrected feeding rates did not differ between larvae from both treatments. Calculating scope for growth illustrates that larvae raised under high pCO(2) spent an average of 39 to 45% of the available energy for somatic growth, while control larvae could allocate between 78 and 80% of the available energy into growth processes. Our results highlight the importance of defining a standard frame of reference when comparing a given parameter between treatments, as observed differences can be easily due to comparison of different larval ages with their specific set of biological characters

Energy metabolism and regeneration impaired by seawater acidification in the infaunal brittlestar, Amphiura filiformis

Seawater acidification due to anthropogenic release of CO2 as well as the potential leakage of pure CO2 from sub-seabed carbon capture storage sites (CCS) may impose a serious threat to marine organisms. Although infaunal organisms can be expected to be particularly impacted by decreases in seawater pH, due to naturally acidified conditions in benthic habitats, information regarding physiological and behavioral responses is still scarce. Determination of pO2 and pCO2 gradients within the burrows of the brittlestar Amphiura filiformis during environmental hypercapnia demonstrated that besides hypoxic conditions, increases of environmental pCO2 are additive to the already high pCO2 (up to 0.08 kPa) within the burrows. In response to up to 4 weeks exposure to pH 7.3 (0.3 kPa pCO2) and pH 7.0 (0.6 kPa pCO2), metabolic rates of A.filiformis were significantly reduced in pH 7.0 treatments accompanied by increased ammonium excretion rates. Gene expression analyses demonstrated significant reductions of acid-base (NBCe and AQP9) and metabolic (G6PDH, LDH) genes. Determination of extracellular acid-base status indicated an uncompensated acidosis in CO2 treated animals, which could explain depressed metabolic rates. Metabolic depression is associated with a retraction of filter feeding arms into sediment burrows. Regeneration of lost arm tissues following traumatic amputation is associated with significant increases in metabolic rate, and hypercapnic conditions (pH 7.0, 0.6 KPa) dramatically reduce the metabolic scope for regeneration reflected in 80% reductions in regeneration rate. Thus, the present work demonstrates that elevated seawater pCO2 significantly affects the environment and the physiology of infaunal organisms like A. filiformis