New developments in cold neutron storage with perfect crystals Jaekel, M.R.; Jericha, E.; Rauch, H.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2005, Letnik:
539, Številka:
1
Journal Article
Recenzirano
A second generation cold neutron storage apparatus has been installed at the pulsed neutron source ISIS. The instrument VESTA-II is designed to confine neutrons between two Bragg-reflecting perfect ...crystal mirrors and to release them in various pulses. A new type of gating has been realized which allows a flexible control of transmission or reflection by the crystal plates. In combination with various other improvements, it creates the potential to extend the scope of its predecessor VESTA-I and facilitate flexible use of the peak intensity of pulsed neutron sources. We discuss the design and concept of the new instrument, present the first experimental results, and review the key elements of the scientific program for the future.
When auditory and visual speech information are presented together, listeners obtain an audiovisual (AV) benefit or a speech understanding improvement compared with auditory-only (AO) or visual-only ...(VO) presentations. Cochlear-implant (CI) listeners, who receive degraded speech input and therefore understand speech using primarily temporal information, seem to readily use visual cues and can achieve a larger AV benefit than normal-hearing (NH) listeners. It is unclear, however, if the AV benefit remains relatively large for CI listeners when trying to understand foreign-accented speech when compared with unaccented speech. Accented speech can introduce changes to temporal auditory cues and visual cues, which could decrease the usefulness of AV information. Furthermore, we sought to determine if the AV benefit was relatively larger in CI compared with NH listeners for both unaccented and accented speech.
AV benefit was investigated for unaccented and Spanish-accented speech by presenting English sentences in AO, VO, and AV conditions to 15 CI and 15 age- and performance-matched NH listeners. Performance matching between NH and CI listeners was achieved by varying the number of channels of a noise vocoder for the NH listeners. Because of the differences in age and hearing history of the CI listeners, the effects of listener-related variables on speech understanding performance and AV benefit were also examined.
AV benefit was observed for both unaccented and accented conditions and for both CI and NH listeners. The two groups showed similar performance for the AO and AV conditions, and the normalized AV benefit was relatively smaller for the accented than the unaccented conditions. In the CI listeners, older age was associated with significantly poorer performance with the accented speaker compared with the unaccented speaker. The negative impact of age was somewhat reduced by a significant improvement in performance with access to AV information.
When auditory speech information is degraded by CI sound processing, visual cues can be used to improve speech understanding, even in the presence of a Spanish accent. The AV benefit of the CI listeners closely matched that of the NH listeners presented with vocoded speech, which was unexpected given that CI listeners appear to rely more on visual information to communicate. This result is perhaps due to the one-to-one age and performance matching of the listeners. While aging decreased CI listener performance with the accented speaker, access to visual cues boosted performance and could partially overcome the age-related speech understanding deficits for the older CI listeners.
The rock-hosted, oceanic crustal aquifer is one of the largest ecosystems on Earth, yet little is known about its indigenous microorganisms. Here we provide the first phylogenetic and functional ...description of an active microbial community residing in the cold oxic crustal aquifer. Using subseafloor observatories, we recovered crustal fluids and found that the geochemical composition is similar to bottom seawater, as are cell abundances. However, based on relative abundances and functional potential of key bacterial groups, the crustal fluid microbial community is heterogeneous and markedly distinct from seawater. Potential rates of autotrophy and heterotrophy in the crust exceeded those of seawater, especially at elevated temperatures (25 °C) and deeper in the crust. Together, these results reveal an active, distinct, and diverse bacterial community engaged in both heterotrophy and autotrophy in the oxygenated crustal aquifer, providing key insight into the role of microbial communities in the ubiquitous cold dark subseafloor biosphere.
The evolutionary history of the largest salamander family (Plethodontidae) is characterized by extreme morphological homoplasy. Analysis of the mechanisms generating such homoplasy requires an ...independent molecular phylogeny. To this end, we sequenced 24 complete mitochondrial genomes (22 plethodontids and two outgroup taxa), added data for three species from GenBank, and performed partitioned and unpartitioned Bayesian, maximum likelihood, and maximum parsimony phylogenetic analyses. We explored four dataset partitioning strategies to account for evolutionary process heterogeneity among genes and codon positions, all of which yielded increased model likelihoods and decreased numbers of supported nodes in the topologies (Bayesian posterior probability >0.95) relative to the unpartitioned analysis. Our phylogenetic analyses yielded congruent trees that contrast with the traditional morphology-based taxonomy; the monophyly of three of four major groups is rejected. Reanalysis of current hypotheses in light of these evolutionary relationships suggests that (i) a larval life history stage reevolved from a direct-developing ancestor multiple times; (ii) there is no phylogenetic support for the "Out of Appalachia" hypothesis of plethodontid origins; and (iii) novel scenarios must be reconstructed for the convergent evolution of projectile tongues, reduction in toe number, and specialization for defensive tail loss. Some of these scenarios imply morphological transformation series that proceed in the opposite direction than was previously thought. In addition, they suggest surprising evolutionary lability in traits previously interpreted to be conservative.
Porphine Homocoupling on Au(111) Seufert, K; McBride, F; Jaekel, S ...
Journal of physical chemistry. C,
07/2019, Letnik:
123, Številka:
27
Journal Article
Recenzirano
The covalent coupling of porphine molecules on Au(111) is studied by scanning probe microscopy experiments and density functional theory. At sufficient temperatures, dehydrogenative C–C coupling of ...the unfunctionalized molecules occurs directly on the surface. Characteristic dimer structures between individual porphine molecules are observed and assigned to various binding motifs that are distinguished by specific intermolecular connections. Different preparations show that the relative abundance of these motifs depends on the temperature of the gold sample during deposition and is explained by calculated free energies and kinetic aspects that are relevant during the linking process. Observations on the gold terraces are completed by studying polymerization at step edges, giving insight into their role during the covalent linking process.
•A scalable standard framework for managing railway operations is presented.•A web-based architecture communicates standard railML data among modules.•A proof-of-concept is provided by an application ...to the Swedish Iron Ore line.•The framework works independently from the algorithm for optimal replanning used.•The bases are set for achieving real-life interoperable traffic management.
Automatic real-time control of traffic perturbations has recently become a central issue for many European railway infrastructure managers. The aim is to make use of mathematical algorithms to maintain the required service availability during unplanned disturbances to operations. In the literature many tools for real-time traffic control are proposed, but their effects on traffic have never been studied neither in real life nor in fully realistic simulation environments. We can mention only a few pilot tests and a unique installation in the Lötschberg Base tunnel in Switzerland, which uses a replanning framework that is generally applicable but does not consider a standard data communication format. Standardisation of railway data is instead one of the main requirements of the European Railway Traffic Management System (ERTMS) to enable traffic interoperability across different countries along the Trans-European Transport Network (TEN-T). Following this direction, this paper introduces one of the outputs of the European project ON-TIME: a framework for the automatic real-time management of railway traffic, designed for being standard and interoperable across different European railways. We make use of a web-based Service-Oriented Architecture to ensure scalability and flexibility of application. A standard railML interface is used for the input/output data of the modules, allowing immediate applicability of the framework to any network having a railML representation. A proof-of-concept is provided where the framework is tested in a closed-loop with the simulation environment HERMES for perturbed traffic scenarios on different networks in the UK, the Netherlands and Sweden. Tests are performed for two different replanning algorithms (ROMA and RECIFE) used for the automatic detection and optimised resolution of train conflicts. The two algorithms are compared on the test case in Sweden. Results show that the design of the proposed framework is effective in managing traffic perturbations and is extendible to real-life systems.
Approximately 30,000 people are affected by severe injuries in Germany each year. Continuous progress in prehospital and hospital care has significantly reduced the mortality of polytrauma patients. ...With increasing survival rates, the functional outcome, health-related quality (hrQoL) of life and ability to work are now gaining importance. Aim of the study is, the presentation of the response behavior of seriously injured patients on the one hand and the examination of the factors influencing the quality of life and ability to work 12 months after major trauma on the other hand. Building on these initial results, a standard outcome tool shall be integrated in the established TraumaRegister DGUR in the future. In 2018, patients Injury Severity Score (ISS) greater than or equal to 16; age:18-75 years underwent multicenter one-year posttraumatic follow-up in six study hospitals. In addition to assessing hrQoL by using the Short-Form Health Survey (SF-12), five additional questions (treatment satisfaction; ability to work; trauma-related medical treatment; relevant physical disability, hrQoL as compared with the prior to injury status) were applied. Of the 1,162 patients contacted, 594 responded and were included in the analysis. The post-injury hrQoL does not show statistically significant differences between the sexes. Regarding age, however, the younger the patient at injury, the better the SF-12 physical sum score. Furthermore, the physically perceived quality of life decreases statistically significantly in relation to the severity of the trauma as measured by the ISS, whereas the mentally perceived quality of life shows no differences in terms of injury severity. A large proportion of severely injured patients were very satisfied (42.2%) or satisfied (39.9%) with the treatment outcome. It should be emphasized that patients with a high injury severity (ISS > 50) were on average more often very satisfied with the treatment outcome (46.7%). A total of 429 patients provided information on their ability to work 12 months post-injury. Here, 194 (45.2%) patients had a full employment, and 58 (13.5%) patients were had a restricted employment. The present results show the importance of a structured assessment of the postinjury hrQoL and the ability to work after polytrauma. Further studies on the detection of influenceable risk factors on hrQoL and ability to work in the intersectoral course of treatment should follow to enable the best possible outcome of polytrauma survivors.
Ice nucleating particles (INPs) affect the radiative properties of cold clouds. Knowledge concerning their concentration above ground level and their potential sources is scarce. Here we present the ...first highly temperature resolved ice nucleation spectra of airborne samples from an aircraft campaign during late winter in 2018. Most INP spectra featured low concentration levels (<3 · 10−4 L−1 at −15°C). However, we also found INP concentrations of up to 1.8·10−2 L−1 at −15°C and freezing onsets as high as −7.5°C for samples mainly from the marine boundary layer. Shape and onset temperature of the ice nucleation spectra of those samples as well as heat sensitivity hint at biogenic INP. Colocated measurements additionally indicate a local marine influence rather than long‐range transport. Our results suggest that even in late winter above 80°N a local marine source for biogenic INP, which can efficiently nucleate ice at high temperatures, is present.
Plain Language Summary
Clouds are a key factor in the energy budget of the Arctic atmosphere. Ice nucleating particles (INPs) can modify the radiation properties and lifetime of clouds by affecting the relative abundance of liquid and frozen droplets in a cloud. Despite this important ability, knowledge about the INP concentration above ground level is limited as airborne INP measurements are very scarce in the Arctic. Here we present results from an aircraft campaign, which took place during the late winter of 2018 in latitudes above 80°N. We found INP concentrations at above −15°C, which are similar to those found in midlatitudes. These INPs also initiate freezing already at high temperatures. We found indications that the INPs are biogenic and originate from a local, marine source, rather than being transported from midlatitudes into the Arctic. Due to the presence of numerous cracks, open leads and polynyas in the sea ice in the investigation area, the ocean may provide a source for these biogenic INP in an environment, where sources on land are still shrouded in snow and ice. However, in a warming Arctic contributions from different sources might change, making the characterization of the current state important.
Key Points
Ice nucleating particles on airborne filter samples containing mainly Arctic marine boundary layer aerosol initiate freezing at −7.5°C
At −15°C, concentrations of ice nucleating particles ranged from up to 2 · 10−2 L−1 down to below 10−3 L−1
A local marine source and biogenic origin for the high‐temperature ice nucleating particles is likely
Allergy to the short ragweed (Ambrosia artemisiifolia) pollen is a major health problem. The ragweed allergen repertoire has been recently expanded with the identification of Amb a 11, a new major ...allergen belonging to the cysteine protease family. To better characterize Amb a 11, a recombinant proform of the molecule with a preserved active site was produced in Escherichia coli, refolded, and processed in vitro into a mature enzyme. The enzymatic activity is revealed by maturation following an autocatalytic processing resulting in the cleavage of both N- and C-terminal propeptides. The 2.05-Å resolution crystal structure of pro-Amb a 11 shows an overall typical C1A cysteine protease fold with a network of molecular interactions between the N-terminal propeptide and the catalytic triad of the enzyme. The allergenicity of Amb a 11 was confirmed in a murine sensitization model, resulting in airway inflammation, production of serum IgEs, and induction of Th2 immune responses. Of note, inflammatory responses were higher with the mature form, demonstrating that the cysteine protease activity critically contributes to the allergenicity of the molecule. Collectively, our results clearly demonstrate that Amb a 11 is a bona fide cysteine protease exhibiting a strong allergenicity. As such, it should be considered as an important molecule for diagnosis and immunotherapy of ragweed pollen allergy.
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