848 research outputs found
Orientation dependence of thermal and mechanical hysteresis in Ni51Fe18Ga27Co4 single crystals
The orientation dependence of thermal ΔТ and mechanical Δσ hysteresis was investigated in Ni51Fe18Ga27Co4 single crystals as-grown with isobaric (shape memory effect) and isothermal (superelasticity) experiments. Single crystals oriented along the [001]-direction show a high reversible deformation of 001 ЭПФ ε = (4,0 ± 0,2) % for martensitic transformations, small thermal hysteresis ΔТ = (22 ± 2) K and mechanical Δσ001 = (47 ± 2) МПа hysteresis, as compared with to single crystals oriented along the [110]-direction. Such orientation dependence is determined by the contribution of the L10-martensite under the εdetw in deformation of transformation
Acute angiotensin II receptor blockade facilitates parahippocampal processing during memory encoding in high-trait-anxious individuals
Background
Angiotensin II receptor blockers (ARBs) have been associated with preventing posttraumatic stress disorder symptom development and improving memory. However, the underlying neural mechanisms are poorly understood. This study investigated ARB effects on memory encoding and hippocampal functioning that have previously been implicated in posttraumatic stress disorder development.
Methods
In a double-blind randomized design, 40 high-trait-anxious participants (33 women) received the ARB losartan (50 mg) or placebo. At drug peak level, participants encoded images of animals and landscapes before undergoing functional magnetic resonance imaging, where they viewed the encoded familiar images and unseen novel images to be memorized and classified as animals/landscapes. Memory recognition was assessed 1 hour after functional magnetic resonance imaging. To analyze neural effects, whole-brain analysis, hippocampus region-of-interest analysis, and exploratory multivariate pattern similarity analysis were employed.
Results
ARBs facilitated parahippocampal processing. In the whole-brain analysis, losartan enhanced brain activity for familiar images in the parahippocampal gyrus (PHC), anterior cingulate cortex, and caudate. For novel images, losartan enhanced brain activity in the PHC only. Pattern similarity analysis showed that losartan increased neural stability in the PHC when processing novel and familiar images. However, there were no drug effects on memory recognition or hippocampal activation.
Conclusions
Given that the hippocampus receives major input from the PHC, our findings suggest that ARBs may modulate higher-order visual processing through parahippocampal involvement, potentially preserving intact memory input. Future research needs to directly investigate whether this effect may underlie the preventive effects of ARBs in the development of posttraumatic stress disorder
On Non-Abelian Symplectic Cutting
We discuss symplectic cutting for Hamiltonian actions of non-Abelian compact
groups. By using a degeneration based on the Vinberg monoid we give, in good
cases, a global quotient description of a surgery construction introduced by
Woodward and Meinrenken, and show it can be interpreted in algebro-geometric
terms. A key ingredient is the `universal cut' of the cotangent bundle of the
group itself, which is identified with a moduli space of framed bundles on
chains of projective lines recently introduced by the authors.Comment: Various edits made, to appear in Transformation Groups. 28 pages, 8
figure
Representativeness and repeatability of microenvironmental personal and head exposures to radio-frequency electromagnetic fields
The aims of this study were to: i) investigate the repeatability and representativeness of personal radio frequency-electromagnetic fields (RF-EMFs) exposure measurements, across different microenvironments, ii) perform simultaneous evaluations of personal RF-EMF exposures for the whole body and the head, iii) validate the data obtained with a head-worn personal distributed exposimeter (PDE) against those obtained with an on-body worn personal exposimeter (PEM). Data on personal and head RF-EMF exposures were collected by performing measurements across 15 microenvironments in Melbourne, Australia. A body-worn PEM and a head-worn PDE were used for measuring body and head exposures, respectively. The summary statistics obtained for total RF-EMF exposure showed a high representativeness (r(2) > 0.66 for two paths in the same area) and a high repeatability over time (r(2) > 0.87 for repetitions of the same path). The median head exposure in the 900 MHz downlink band ranged between 0.06 V/m and 0.31 V/m. The results obtained during simultaneous measurements using the two devices showed high correlations (0.42 < r(2) < 0.94). The highest mean total RF-EMF exposure was measured in Melbourne's central business district (0.89 V/m), whereas the lowest mean total exposure was measured in a suburban residential area (0.05 V/m). This study shows that personal RF-EMF microenvironmental measurements in multiple microenvironments have high representativeness and repeatability over time. The personal RF-EMF exposure levels (i.e. body and head exposures) demonstrated moderate to high correlations
Phylogeny of the Eurasian Wren Nannus troglodytes (Aves: Passeriformes: Troglodytidae) reveals deep and complex diversification patterns of Ibero-Maghrebian and Cyrenaican populations
Acknowledgments We are indebted to S. Birks (Burke Museum of Natural History and Culture, Seattle, WA, USA) and to J.-M. Pons (L’Institut de Systématique, Évolution, Biodiversité, Muséum national d’histoire naturelle, Paris, France), who kindly provided access to genetic material from their collections. We also thank G. López and CHAGRA ringing group for providing samples. All genetic analyses were performed at SGN-SNSD-Mol-Lab and we are grateful to A. Rauh, C. Spitzweg, A. Müller, and C. Kehlmaier for practical help in the molecular lab facilities. We would also like to thank M. Vamberger for support in phylogenetic analyses. Finally, we would like to thank four anonymous reviewers for constructive criticism on the manuscript. Erratum: Phylogeny of the Eurasian Wren Nannus troglodytes (Aves: Passeriformes: Troglodytidae) reveals deep and complex diversification patterns of Ibero-Maghrebian and Cyrenaican populations (PLoS ONE) (2020) 15: 3 (e0230151) DOI: 10.1371/journal.pone.0230151) F. Albrecht, J. Hering, E. Fuchs, J.C. Illera, F. Ihlow, T.J. Shannon, 2020. PLoS ONEPeer reviewedPublisher PD
Resonant Mie Scattering (RMieS) correction of infrared spectra from highly scattering biological samples
Infrared spectra of single biological cells often exhibit the “dispersion artefact” observed as a sharp decrease in intensity on the high wavenumber side of absorption bands, in particular the Amide I band at ~1655 cm-1, causing a downward shift of the true peak position. The presence of this effect makes any biochemical interpretation of the spectra unreliable. Recent theory has shed light on the origins of the ‘dispersion artefact’ which has been attributed to resonant Mie scattering (RMieS). In this paper a preliminary algorithm for correcting RMieS is presented and evaluated using simulated data. Results show that the ‘dispersion artefact’ appears to be removed, however, the correction is not perfect. An iterative approach was subsequently implemented whereby the reference spectrum is improved after each iteration, resulting in a more accurate correction. Consequently the corrected spectra become increasingly more representative of the pure absorbance spectra. Using this correction method reliable peak positions can be obtained
Physical and Biogeochemical Studies in the Subtropical and Tropical Atlantic
Maria S. Merian Cruise Report MSM18/L2
Cruise No. 18, Leg 2
May 11 – June 19, 2011
Mindelo (Cape Verde Islands) – Mindelo (Cape Verde Islands
Tomographic image of melt storage beneath Askja Volcano, Iceland using local microseismicity
We use P wave and S wave arrivals from microseismic earthquakes to construct 3-D tomographic Vp and Vs images of the magma storage region beneath Askja's central volcano in the Northern Volcanic Zone of Iceland. A distinctive ellipsoidal low-velocity anomaly, with both Vp and Vsvelocities 8-12% below the background, is imaged at 6-11 km depth beneath the caldera. The presence of a shallow magma chamber is corroborated by geodetic and gravity studies. The small Vp/Vs anomaly suggests a lack of pervasive melt. We interpret this anomaly as a region of multiple sills, some frozen but hot, others containing partial melt. A second, smaller low-velocity anomaly beneath the main magma storage region may represent a magma migration pathway. This interpretation is supported by the close proximity to the anomaly of clusters of deep, magmatically induced earthquakes. However, the location and shape of this deep anomaly are poorly constrained by the current data set
Maximal Temperature in Flux Compactifications
Thermal corrections have an important effect on moduli stabilization leading
to the existence of a maximal temperature, beyond which the compact dimensions
decompactify. In this note, we discuss generality of our earlier analysis and
apply it to the case of flux compactifications. The maximal temperature is
again found to be controlled by the supersymmetry breaking scale, T_{crit} \sim
\sqrt{m_{3/2} M_P}.Comment: 10 pages, 10 figures. v2:comment and references adde
- …