Effects of ground movements on realistic guide models for the European Spallation Source

We model the effect of ground movement, based on empirical experience, on the transport properties of long neutron guides by ray-tracing simulations. Our results reproduce the large losses found by an earlier study for a simple model, while for a more realistic engineering model of guide mounting, we find the losses to be significantly smaller than earlier predicted. A detailed study of the guide for the cold neutron spectrometer BIFROST at the European Spallation Source shows that the loss is 7.0(5) % for wavelengths of 2.3-4.0 {\AA}; the typical operational wavelength range of the instrument. This amount of loss does not call for mitigation by overillumination as suggested in the previous work. Our work serves to quantify the robustness of the transport properties of long neutron guides, in construction or planning at neutron facilities worldwide.Comment: 8 pages, 12 figure

Triangular prism-shaped β-peptoid helices as unique biomimetic scaffolds

β-Peptoids are peptidomimetics based on N-alkylated β-aminopropionic acid residues (or N-alkyl-β-alanines). This type of peptide mimic has previously been incorporated in biologically active ligands and has been hypothesized to be able to exhibit foldamer properties. Here we show, for the first time, that β-peptoids can be tuned to fold into stable helical structures. We provide high-resolution X-ray crystal structures of homomeric β-peptoid hexamers, which reveal right-handed helical conformations with exactly three residues per turn and a helical pitch of 9.6–9.8 Å between turns. The presence of folded conformations in solution is supported by circular dichroism spectroscopy showing length- and solvent dependency, and molecular dynamics simulations provide further support for a stabilized helical secondary structure in organic solvent. We thus outline a framework for future design of novel biomimetics that display functional groups with high accuracy in three dimensions, which has potential for development of new functional materials

Acceptable noise level: Repeatability with Danish and non-semantic speech materials for adults with normal hearing

Objective: The acceptable noise level (ANL) is used to quantify the amount of background noise that subjects can accept while listening to speech, and is suggested for prediction of individual hearing-aid use. The aim of this study was to assess the repeatability of the ANL measured in normal-hearing subjects using running Danish and non-semantic speech materials as stimuli and modulated speech-spectrum and multi-talker babble noises as competing stimuli. Design: ANL was measured in both ears at two test sessions separated by a period ranging from 12 to 77 days. At each session the measurements at the first and the second ear were separated in time by 15-30 minutes. Bland-Altman plots and calculation of the coefficient of repeatability (CR) were used to estimate the repeatability. Study sample: Thirty nine normal-hearing subjects. Results: The ANL CR was 6.0-8.9 dB for repeated tests separated by about 15-30 minutes and 7.2-10.2 dB for repeated tests separated by 12 days or more. Conclusions: The ANL test has poor repeatability when assessed with Danish and non-semantic speech materials on normal-hearing subjects. The same CR among hearing-impaired subjects would imply too poor repeatability to predict individual patterns of future hearing-aid use

Acceptable noise level with Danish, Swedish, and non-semantic speech materials.

Objective: Acceptable noise level (ANL) has been established as a method to quantify the acceptance of background noise while listening to speech presented at the most comfortable level. The aim of the present study was to generate Danish, Swedish, and a non-semantic version of the ANL test and investigate normal-hearing Danish and Swedish subjects' performance on these tests. Design: ANL was measured using Danish and Swedish running speech with two different noises: Speech-weighted amplitude-modulated noise, and multitalker speech babble. ANL was also measured using the non-semantic international speech test signal (ISTS) as speech signal together with the speech-weighted amplitude-modulated noise. The latter condition was identical in both populations. Study sample: Forty Danish and 40 Swedish normal-hearing subjects. Results: In both populations ANL results were similar to previously reported results from American studies. Generally, significant differences were seen between test conditions using different types of noise within ears in each population. Significant differences were seen for ANL across populations, also when the non-semantic ISTS was used as speech signal. Conclusions: The present findings indicate that there are extrinsic factors, such as instructions, affecting the ANL results. Summario Objetivo: Se ha establecido el Nivel de Ruido Aceptable (ANL) como un método para cuantifi car la aceptación de ruido de fondo mientras se escucha lenguaje presentado al nivel más confortable. El objetivo de este estudio fue generar las versiones sueca, danesa y una no-semántica de la prueba ANL e investigar el desempeño de sujetos normoyentes daneses y suecos en estas pruebas. Diseño: Se midió el ANL utilizando un discurso continuo en danés y sueco con dos diferentes ruidos: ruido con amplitud modulada en el rango del lenguaje y balbuceo de varios hablantes. También se midió el ANL utilizando la prueba internacional no-semántica de señal de lenguaje (ISTS) como la señal lingüística junto con ruido con amplitud modulada en el rango del lenguaje. Esta última condición fue idéntica en ambas poblaciones. Muestra: Cuarenta sujetos daneses y 40 sujetos suecos normoyentes. Resultados: en ambas poblaciones los resultados de ANL fueron muy similares a los reportado previamente en estudios americanos. Generalmente, se vieron diferencias signifi cativas para el ANL entre poblaciones, también cuando el ISTS no semántico fue utilizado como señal lingüística. Conclusiones: Estos hallazgos indican que hay factores extrínsecos tales como las instrucciones, que afectan los resultados de ANL