Results of Operational Sea-Wave Monitoring with Radar Gauges

The German Federal Institute of Hydrology (BfG) developed a low-cost, non-contact sea-wave monitoring system based on a single radar sensor. A short description of the measuring system and the analysis of wave parameters is given. Furthermore, long-term wave measurements with this system, in combination with wind-measurements and statistics, are used to analyse possible future changes in wave heights. The results are in good agreement with those of other methods. Due to the good results achieved with the single radar sensor, an extension of the system which will be capable of recording directional information, is now under development. First results are presented in this study.El Instituto Federal Alemán de Hidrología (BfG) ha desarrollado un sistema de seguimiento de bajo coste, que no tiene contacto con la ola, basado en un sensor con un único radar. Se proporciona en el presente artículo una breve descripción del sistema de medición y del análisis de los parámetros de las olas. Además, las mediciones de olas por periodos largos efectuadas con este sistema, en combinación con las medidas del viento y las estadísti-cas, se utilizan para analizar los posibles cambios futuros en las alturas de las olas. Los resultados concuerdan con aquellos obtenidos mediante otros métodos. Debido a los buenos resultados obtenidos con el sensor de radar único, una extensión del sistema, que está ahora en fase de desarrollo, podrá registrar la información direccional. En este estudio se presentan los primeros resultados.L’Institut fédéral allemand d’hydrologie (BfG) a élaboré un système peu onéreux de surveillance à distance des vagues à partir d’un unique sondeur radar. Une brève description du système de mesure ainsi que l’analyse des paramètres des vagues est donnée. De plus, les mesures à long-terme des vagues avec ce système, combinées avec les mesures du vent et les statistiques sont utilisées pour analyser les changements futurs possibles des hauteurs de vagues. Les résultats concordent avec ceux établis au moyen d’autres méthodes. Du fait des bons résultats de l’unique sondeur radar, une extension du système qui pourrait enregistrer des informations relatives à la direction, est actuellement en cours de développement. Les premiers résultats sont présentés dans cette étud

Quantum spins and hybridization in artificially-constructed chains of magnetic adatoms on a superconductor

Magnetic adatom chains on surfaces constitute fascinating quantum spin systems. Superconducting substrates suppress interactions with bulk electronic excitations but couple the adatom spins to a chain of subgap Yu-Shiba-Rusinov (YSR) quasiparticles. Using a scanning tunneling microscope, we investigate such correlated spin-fermion systems by constructing Fe chains adatom by adatom on superconducting NbSe$_2$. The adatoms couple entirely via the substrate, retaining their quantum spin nature. In dimers, we observe that the deepest YSR state undergoes a quantum phase transition due to Ruderman-Kittel-Kasuya-Yosida interactions, a distinct signature of quantum spins. Chains exhibit coherent hybridization and band formation of the YSR excitations, indicating ferromagnetic coupling. Longer chains develop separate domains due to coexisting charge-density-wave order of NbSe$_2$. Despite the spin-orbit-coupled substrate, we find no signatures of Majoranas, possibly because quantum spins reduce the parameter range for topological superconductivity. We suggest that adatom chains are versatile systems for investigating correlated-electron physics and its interplay with topological superconductivity

Original experimental data and code for the Paper ”Quantum spins and hybridization in artificially-constructed chains of magnetic adatoms on a superconductor“

Magnetic adatom chains on surfaces constitute fascinating quantum spin systems. Superconducting substrates suppress interactions with bulk electronic excitations but couple the adatom spins to a chain of subgap Yu-Shiba-Rusinov (YSR) quasiparticles. Using a scanning tunneling microscope, we investigate such correlated spin-fermion systems by constructing Fe chains adatom by adatom on superconducting NbSe2. The adatoms couple entirely via the substrate, retaining their quantum spin nature. In dimers, we observe that the deepest YSR state undergoes a quantum phase transition due to Ruderman-Kittel-Kasuya-Yosida interactions, a distinct signature of quantum spins. Chains exhibit coherent hybridization and band formation of the YSR excitations, indicating ferromagnetic coupling. Longer chains develop separate domains due to coexisting charge-density-wave order of NbSe2. Despite the spin-orbit-coupled substrate, we find no signatures of Majoranas, possibly because quantum spins reduce the parameter range for topological superconductivity. We suggest that adatom chains are versatile systems for investigating correlated-electron physics and its interplay with topological superconductivity

Osteosarcopenia, an Asymmetrical Overlap of Two Connected Syndromes: Data from the OsteoSys Study

Osteoporosis and sarcopenia are two chronic conditions, which widely affect older people and share common risk factors. We investigated the prevalence of low bone mineral density (BMD) and sarcopenia, including the overlap of both conditions (osteosarcopenia) in 572 older hospitalized patients (mean age 75.1 ± 10.8 years, 78% women) with known or suspected osteoporosis in this prospective observational multicenter study. Sarcopenia was assessed according to the revised defini tion of the European Working Group on Sarcopenia in Older People (EWGSOP2). Low BMD was defined according to the World Health Organization (WHO) recommendations as a T-score < −1.0. Osteosarcopenia was diagnosed when both low BMD and sarcopenia were present. Low BMD was prevalent in 76% and the prevalence of sarcopenia was 9%, with 90% of the sarcopenic patients showing the overlap of osteosarcopenia (8% of the entire population). Conversely, only few patients with low BMD demonstrated sarcopenia (11%). Osteosarcopenic patients were older and frailer and had lower BMI, fat, and muscle mass, handgrip strength, and T-score compared to nonosteosar copenic patients. We conclude that osteosarcopenia is extremely common in sarcopenic subjects. Considering the increased risk of falls in patients with sarcopenia, they should always be evaluated for osteoporosis

Noble gases sampled from three cruises in the eastern tropical Atlantic

Oceanic upwelling velocities are too small to be measured directly. Deviations of the He-3/He-4 ratio in the mixed layer from solubility equilibrium provide an indirect means to infer vertical velocities at the base of the mixed layer. This method is applied to the Mauritanian upwelling region for data from three cruises in summer 2006 and winter 2007 and 2008. Diapycnal mixing coefficients are estimated from microstructure measurements, reaching from 10**-3 m**2/s over the shelf break to 10**-5 m**2/s in the open ocean. The resulting upwelling velocities in the onshore region (upto 50 km from the 50 m isobath) are of the order of 2 x 10**-5 m/s}, in agreement with Ekman theory. Further offshore, in some cases the vertical velocities inferred from the helium isotope disequilibrium exceed the values derived from the wind stress curl by one order of magnitude. The Mauritanian coastal area as part of the Canary Current upwelling system belongs to the most productive ocean regions in the world. Nutrient fluxes into the mixed layer (both advective and diffusive) are equivalent to a net community production of about 1 g C/d, and associated heat fluxes vary between 183 +/- 62 W/m**2 in summer and 97 +/- 25 W/m**2 in winter. Regarding the flux into the mixed layer, the contribution of diffusion and advection are of similar magnitude for both heat and nutrients. The upwelling, however, provides the supply of cold and nutrient rich water from below. The large offshore vertical velocities inferred from the helium method are associated with nutrient fluxes of the same order as for the onshore region, and may be responsible for observed patches of high productivity in that area. The offshore heat fluxes due to upwelling and diapycnal mixing are smaller than 70 W/m**2 for all cruises