2,054 research outputs found
Instrument to collect fogwater for chemical analysis
An instrument is presented which collects large samples of ambient fogwater by impaction of droplets on a screen. The collection efficiency of the instrument is determined as a function of droplet size, and it is shown that fog droplets in the range 3–100-µm diameter are efficiently collected. No significant evaporation or condensation occurs at any stage of the collection process. Field testing indicates that samples collected are representative of the ambient fogwater. The instrument may easily be automated, and is suitable for use in routine air quality monitoring programs
Ammonoid soft tissue remains revealed by computed tomography
Findings of ammonoid soft tissues are extremely rare compared to the rich fossil record of ammonoid conchs ranging from the Late Devonian to the Cretaceous/Paleogene boundary. Here, we apply the computed-tomography approach to detect ammonoid soft tissue remains in well-preserved fossils from the Early Cretaceous (early Albian) of NE-Germany of Proleymeriella. The ammonites were found in glauconitic–phosphatic sandstone boulders. Analyses of the high-resolution Ct-data revealed the presence of cameral sheets, the siphuncular tube wall, and the siphuncle itself. The siphuncle is a long, segmented soft tissue that begins at the rear end of the body chamber and comprises blood vessels. Chemical analyses using energy-dispersive spectroscopy (EDS) showed that all preserved soft tissues were phosphatized and are now composed of fluorapatite. The same holds true for preserved shell remains that locally show the nacreous microstructure. We provide a short description of these soft tissue remains and briefly discuss the taphonomic pathway.Fil: Hoffmann, R.. Ruhr-Universität Bochum; AlemaniaFil: Moron Alfonso, Daniel Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Klug, C.. Universitat Zurich; SuizaFil: Tanabe, K.. The University Of Tokyo; Japó
Determining the unsaturated hydraulic conductivity of a compacted sand-bentonite mixture under constant volume and free-swell conditions
Highly compacted sand-bentonite mixtures are often considered as possible
engineered barriers in deep high-level radioactive waste disposals. In-situ,
the saturation of these barriers from their initially unsaturated state is a
complex hydro-mechanical coupled process in which temperature effects also play
a role. The key parameter of this process is the unsaturated hydraulic
conductivity of the barrier. In this paper, isothermal infiltration experiments
were conducted to determine the unsaturated hydraulic conductivity according to
the instantaneous profile method. To do so, total suction changes were
monitored at different locations along the soil specimen by using resistivity
relative humidity probes. Three constant volume infiltration tests were
conducted showing, unexpectedly, a decrease of the hydraulic conductivity
during infiltration. One test performed under free-swell conditions showed the
opposite and standard trend. These observations were interpreted in terms of
microstructure changes during wetting, both under constant volume and free
swell conditions
Protein dynamics with off-lattice Monte Carlo moves
A Monte Carlo method for dynamics simulation of all-atom protein models is
introduced, to reach long times not accessible to conventional molecular
dynamics. The considered degrees of freedom are the dihedrals at
C-atoms. Two Monte Carlo moves are used: single rotations about
torsion axes, and cooperative rotations in windows of amide planes, changing
the conformation globally and locally, respectively. For local moves Jacobians
are used to obtain an unbiased distribution of dihedrals. A molecular dynamics
energy function adapted to the protein model is employed. A polypeptide is
folded into native-like structures by local but not by global moves.Comment: 10 pages, 4 Postscript figures, uses epsf.sty and a4.sty; scheduled
tentatively for Phys.Rev.E issue of 1 March 199
First application of dynamic oxygen-17 magnetic resonance imaging at 7 Tesla in a patient with early subacute stroke.
Dynamic oxygen-17 (17O) magnetic resonance imaging (MRI) is an imaging method that enables a direct and non-invasive assessment of cerebral oxygen metabolism and thus potentially the distinction between viable and non-viable tissue employing a three-phase inhalation experiment. The purpose of this investigation was the first application of dynamic 17O MRI at 7 Tesla (T) in a patient with stroke. In this proof-of-concept experiment, dynamic 17O MRI was applied during 17O inhalation in a patient with early subacute stroke. The analysis of the relative 17O water (H217O) signal for the affected stroke region compared to the healthy contralateral side revealed no significant difference. However, the technical feasibility of 17O MRI has been demonstrated paving the way for future investigations in neurovascular diseases
Recommended from our members
Electron-ion recombination measurements of Fe7+, Fe8+, Fe13+ motivated by active galactic nuclei x-ray absorption features
Recent spectroscopic models of active galactic nuclei have indicated that the recommended electron-ion recombination rate coefficients for iron ions with partially filled Mshells are incorrect in the temperature range where these ions form in photoionized plasmas. We have investigated this experimentally for Fe7+ forming Fe6+, Fe8+ forming Fe7+, and Fe13+ forming Fe12+. The recombination rate coefficient was measured employing the electron-ion merged beams method at the Heidelberg heavy-ion storage-ring TSR. The measured energy range encompassed at least all dielectronic recombination (DR) resonances associated with core excitations within the M-shell of the parent ions. Already in our first measurement, that is for Fe13+, we find unusually strong DR resonances at low electron-ion collision energies leading to low temperature plasma DR rate coefficients orders of magnitude larger than the recommended rate coefficien
Winegrowers’ decision-making: A pan-European perspective on pesticide use and inter-row management
European viticultural landscapes not only support a significant share of rural livelihoods and cultural traditions, but also conserve biodiversity and sustain various ecosystem services. Winegrowers' practices of inter-row management (including whether to have vegetation in the inter-rows, type of vegetation, duration of vegetation cover, and soil tillage) and pesticide use (including herbicides in the inter-rows, fungicides, insecticides, and pheromone dispensers as an alternative) can affect these services. This study aims to understand winegrowers' decision-making driven by their personal characteristics, attitudes and beliefs towards viticultural practices, physical properties of vineyards, and farm management characteristics in five European winegrowing regions. These include Palatinate in Germany, Leithaberg in Austria, Tarnave in Romania, Bordeaux in France, and Montilla-Moriles in Spain. Based on a questionnaire survey, we constructed decision trees for each behaviour per case study as well as in a generic European model. We found factors that best explain how winegrowers manage their inter-rows and use pesticides. Results showed that not only do behaviours of winegrowers vary drastically across the case studies, but also the factors that explain most behaviours: farmers' attitudes and beliefs and farm management characteristics. This implies the importance of attitudes and beliefs – which are under-researched as compared to other factors – in understanding farmers’ behaviour. With the driving factors found to vary per case study, our results also imply the need for locally-adapted policies. Furthermore, our results suggest that the effects of climate change on European viticultural landscapes concern not only shifting production regions and changes in yields, but also changing pressure of pests and diseases. Any long-term behavioural change requires efforts from many stakeholders.This research was funded by the research project SECBIVIT which was funded through the 2017–2018 Belmont Forum and BiodivERsA joint call for research proposals, under the BiodivScen ERA-Net COFUND programme, with the funding organisations: Agencia Estatal de Investigación (Ministerio de ciencia e innovación/Spain), Austrian Science Fund (FWF) (grant number I 4025-B32), Federal Ministry of Education and Research (BMBF/Germany) through VDI/VDE Innovation + Technik GmbH, DLR Projektträger, French National Research Agency (ANR), Netherlands Organisation for Scientific Research (NWO), National Science Foundation (Grant #1850943) and Romanian Executive Agency for Higher Education, Research, Development and Innovation Funding (UEFISCDI). We would like to thank all winegrowers who participated in the focus groups, online questionnaires and personal interviews and the extension services who distributed our online questionnaire through their e-mail distribution list (DLR-Rheinpfalz)
Effects of beta-alanine supplementation on brain homocarnosine/carnosine signal and cognitive function: an exploratory study
Objectives: Two independent studies were conducted to examine the effects of 28 d of beta-alanine supplementation at 6.4 g d-1 on brain homocarnosine/carnosine signal in omnivores and vegetarians (Study 1) and on cognitive function before and after exercise in trained cyclists (Study 2). Methods: In Study 1, seven healthy vegetarians (3 women and 4 men) and seven age- and sex-matched omnivores undertook a brain 1H-MRS exam at baseline and after beta-alanine supplementation. In study 2, nineteen trained male cyclists completed four 20-Km cycling time trials (two pre supplementation and two post supplementation), with a battery of cognitive function tests (Stroop test, Sternberg paradigm, Rapid Visual Information Processing task) being performed before and after exercise on each occasion. Results: In Study 1, there were no within-group effects of beta-alanine supplementation on brain homocarnosine/carnosine signal in either vegetarians (p = 0.99) or omnivores (p = 0.27); nor was there any effect when data from both groups were pooled (p = 0.19). Similarly, there was no group by time interaction for brain homocarnosine/carnosine signal (p = 0.27). In study 2, exercise improved cognitive function across all tests (P0.05) of beta-alanine supplementation on response times or accuracy for the Stroop test, Sternberg paradigm or RVIP task at rest or after exercise. Conclusion: 28 d of beta-alanine supplementation at 6.4g d-1 appeared not to influence brain homocarnosine/ carnosine signal in either omnivores or vegetarians; nor did it influence cognitive function before or after exercise in trained cyclists
- …