Resonant vibrations, peak broadening and noise in single molecule contacts: beyond the resonant tunnelling picture

We carry out experiments on single-molecule junctions at low temperatures, using the mechanically controlled break junction technique. Analyzing the results received with more than ten different molecules the nature of the first peak in the differential conductance spectra is elucidated. We observe an electronic transition with a vibronic fine structure, which is most frequently smeared out and forms a broad peak. In the usual parameter range we find strong indications that additionally fluctuations become active even at low temperatures. We conclude that the electrical field feeds instabilities, which are triggered by the onset of current. This is underscored by noise measurements that show strong anomalies at the onset of charge transport

Ex-situ and in-situ investigations of thermal anti-oxidation treatments of stainless steels by reflection mode EXAFS

Different thermal treatments were performed for the anti-oxidation of steel surfaces, and the processes were investigated ex-situ and in-situ by surface sensitive reflection mode EXAFS experiments at the Cr and Fe K-edges. While the samples for the ex-situ studies were heat-treated in a conveyor belt furnace at temperatures between 600 and 900 °C in inert carrier gases (N2 or Ar) using different additives such as hydrogen (H2) and monosilane (SiH4), the in- situ anti-oxidation treatments have been performed in a high vacuum environment (p < 10-6 mbar). While the ex-situ experiments suggest that SiH4-additives are needed for the reduction of the steel to a metallic state, the in-vacuum treatments appear successful for temperatures above approx. 900 °C.DFG/FR 1388/8-1DFG/Ma 1175/48-

A modified two-dimensional sensory organization test that assesses both anteroposterior and mediolateral postural control

BackgroundThe Sensory Organization Test (SOT) was designed to measure changes in postural control in response to unreliable visual and/or proprioceptive feedback. However, secondary to the manipulation of sensory cues in only the sagittal plane, the SOT is capable of only describing postural control in a single direction. The present study aimed to characterize postural responses to a modified SOT designed to concurrently challenge both anteroposterior and mediolateral postural control.MethodsTwenty-one healthy adult volunteers (30.6 ± 10.2 years) completed the standard anteroposterior one-dimensional (1D) SOT, in addition to a modified SOT with the support surface sway-referenced to both anteroposterior and mediolateral postural sway (two-dimensional, 2D). Our primary analysis concerned a comparison of mediolateral, as well as anteroposterior postural sway measured during the standard one-dimensional (i.e., pitch tilt) and the novel two-dimensional (i.e., roll and pitch tilt) sway-referenced paradigms. Here, postural sway was quantified by calculating the root mean square distance (RMSD) of the center of pressure (CoP) during each trial.ResultsOur data showed that the 2D sway-referenced conditions yielded a selective increase in mediolateral postural sway relative to the standard 1D conditions for both wide (η2 = 0.66) and narrow (η2 = 0.78) stance conditions, with anteroposterior postural sway being largely unaffected (η2 = 0.001 to 0.103, respectively). The ratio between mediolateral postural sway in the sway-referenced conditions and postural sway in the corresponding stable support surface conditions was greater for the 2D (2.99 to 6.26 times greater) compared to 1D paradigms (1.25 to 1.84 times greater), consistent with a superior degradation of viable proprioceptive feedback in the 2D paradigm.ConclusionA modified 2D version of the SOT was shown to provide a greater challenge to mediolateral postural control relative to the standard 1D SOT protocol, putatively as a result of a superior capacity to degrade proprioceptive feedback in the mediolateral direction. Given these positive findings, future studies should investigate the clinical utility of this modified SOT as a means by which to better characterize sensory contributions to postural control in the presence of various sensorimotor pathologies, including vestibular hypofunction

Strength of the EpE_{\text{p}}=1.842 MeV resonance in the 40^{40}Ca(p,γ\gamma)41^{41}Sc reaction revisited

The strength of the $E_{\rm p} = 1.842$ MeV resonance in the $^{40}$Ca(p,$\gamma$)$^{41}$Sc reaction is determined with two different methods: First, by an absolute strength measurement using calcium hydroxide targets, and second, relative to the well-determined strength of the resonance triplet at $E_\alpha$ = 4.5 MeV in the $^{40}$Ca($\alpha$,$\gamma$)$^{44}$Ti reaction. The present new value of $\omega\gamma=(0.192\pm0.017)$ eV is 37% (equivalent to $3.5\sigma$) higher than the evaluated literature value. In addition, the ratio of the strengths of the 1.842 MeV $^{40}$Ca(p,$\gamma$)$^{41}$Sc and 4.5 MeV $^{40}$Ca($\alpha$,$\gamma$)$^{44}$Ti resonances has been determined to be $0.0229\pm0.0018$. The newly corrected strength of the 1.842-MeV resonance can be used in the future as a normalization point for experiments with calcium targets.Comment: Submitted to Phys. Rev.

Terrestrial solar radiation driven photodecomposition of ciprofloxacin in clinical wastewater applying mesostructured iron(III) oxide

Cationic cylindrical polymer brushes based on polybutadiene-block-poly(2-vinylpyridine) were applied as structure-directing agent for mesostructuring F

The new Felsenkeller 5 MV underground accelerator

The field of nuclear astrophysics is devoted to the study of the creation of the chemical elements. By nature, it is deeply intertwined with the physics of the Sun. The nuclear reactions of the proton-proton cycle of hydrogen burning, including the 3He({\alpha},{\gamma})7Be reaction, provide the necessary nuclear energy to prevent the gravitational collapse of the Sun and give rise to the by now well-studied pp, 7Be, and 8B solar neutrinos. The not yet measured flux of 13N, 15O, and 17F neutrinos from the carbon-nitrogen-oxygen cycle is affected in rate by the 14N(p,{\gamma})15O reaction and in emission profile by the 12C(p,{\gamma})13N reaction. The nucleosynthetic output of the subsequent phase in stellar evolution, helium burning, is controlled by the 12C({\alpha},{\gamma})16O reaction. In order to properly interpret the existing and upcoming solar neutrino data, precise nuclear physics information is needed. For nuclear reactions between light, stable nuclei, the best available technique are experiments with small ion accelerators in underground, low-background settings. The pioneering work in this regard has been done by the LUNA collaboration at Gran Sasso/Italy, using a 0.4 MV accelerator. The present contribution reports on a higher-energy, 5.0 MV, underground accelerator in the Felsenkeller underground site in Dresden/Germany. Results from {\gamma}-ray, neutron, and muon background measurements in the Felsenkeller underground site in Dresden, Germany, show that the background conditions are satisfactory for nuclear astrophysics purposes. The accelerator is in the commissioning phase and will provide intense, up to 50{\mu}A, beams of 1H+, 4He+ , and 12C+ ions, enabling research on astrophysically relevant nuclear reactions with unprecedented sensitivity.Comment: Submitted to the Proceedings of the 5th International Solar Neutrino Conference, Dresden/Germany, 11-14 June 2018, to appear on World Scientific -- updated version (Figure 2 and relevant discussion updated, co-author A. Domula added

Widest geographic distribution of a shallow and mesophotic antipatharian coral (Anthozoa: Hexacorallia): Antipathes grandis VERRILL, 1928 – confirmed by morphometric and molecular analyses

We provide the first record of the shallow and mesophotic ( 200 m depth) benthic taxa have such wide geographic distributions

Device analyzer : a privacy-aware platform to support research on the Android ecosystem

Device Analyzer is an Android app available from the Google Play store. It is designed to collect a large range of data from the handset and, with agreement from our contributors, share it with researchers around the world. Researchers can access the data collected, and can also use the platform to support their own user studies. In this paper we provide an overview of the privacy-enhancing techniques used in Device Analzyer, including transparency, consent, purpose, access, withdrawal, and accountability. We also demonstrate the utility of our platform by assessing the security of the Android ecosystem to privilege escalation attacks and deter-mine that 88% of Android devices are, on average, vulnerable to one or more of these type of attacks