637 research outputs found
Anisotropic electrical resistivity of LaFeAsO: evidence for electronic nematicity
Single crystals of LaFeAsO were successfully grown out of KI flux.
Temperature dependent electrical resistivity was measured with current flow
along the basal plane, \rho_perpend(T), as well as with current flow along the
crystallographic c-axis, \rho_parallel(T), the latter one utilizing electron
beam lithography and argon ion beam milling. The anisotropy ratio was found to
lie between \rho_parallel/\rho_perpend = 20 - 200. The measurement of
\rho_perpend(T) was performed with current flow along the tetragonal [1 0 0]
direction and along the [1 1 0] direction and revealed a clear in-plane
anisotropy already at T \leq 175 K. This is significantly above the
orthorhombic distortion at T_0 = 147 K and indicates the formation of an
electron nematic phase. Magnetic susceptibility and electrical resistivity give
evidence for a change of the magnetic structure of the iron atoms from
antiferromagnetic to ferromagnetic arrangement along the c-axis at T^\ast = 11
K.Comment: 10 pages, 6 figures, minor change
Winter storm risk of residential structures ? model development and application to the German state of Baden-WĂŒrttemberg
International audienceThe derivation of probabilities of high wind speeds and the establishment of risk curves for storm damage is of prime importance in natural hazard risk analysis. Risk curves allow the assessment of damage being exceeded at a given level of probability. In this paper, a method for the assessment of winter storm damage risk is described in detail and applied to the German state of Baden-WĂŒrttemberg. Based on meteorological observations of the years 1971?2000 and on damage information of 4 severe storm events, storm hazard and damage risk of residential buildings is calculated on the level of communities. For this purpose, highly resolved simulations of storm wind fields with the Karlsruher Atmospheric Mesoscale Model (KAMM) are performed and a storm damage model is developed. Risk curves including the quantification of the uncertainties are calculated for every community. Local differences of hazard and risk are presented in state-wide maps. An average annual winter storm damage to residential buildings of minimum 15 million Euro (reference year 2000) for Baden-WĂŒrttemberg is expected
Rooney
Born to an Irish Catholic working-class family on the Northside of Pittsburgh, Art Rooney (1901â88) dabbled in semipro baseball and boxing before discovering that his real talent lay not in playing sports but in promoting them. Though he was at the center of boxing, baseball, and racing in Pittsburgh and beyond, Rooney is best remembered for his contribution to the NFL, in particular to the Pittsburgh Steelers, the team he founded in 1933. As Rooney led the team in the early years, he came to be known as footballâs greatest loser; his influence, however, was instrumental in making the NFL the best-run league in American pro sports. The authors show how Rooney saw professional footballâand the Steelersâthrough the Depression, World War II, the ascension of TV, and the development of the NFL. The book also follows him through the Steelersâ dynasty years under Rooneyâs sons, with four Super Bowl titles in the 1970s alone. The first authoritative look at one of the most iconic figures in the history of the NFL, this book is both a critical chapter in the story of football in America and a thoroughly engaging in-depth introduction to a character unlike any other in the annals of American sports
The Mixed-Valence <i>Catena</i>-Heteropolycation (Bi<sub>2</sub>S<sub>2</sub>)<sup>+</sup>
The reaction of Bi and Bi2S3 in the Lewis-acidic ionic liquid [BMIm]Cl . 4.3AlCl(3) (BMIm=1-n-butyl-3-methylimidazolium) at 200 degrees C yielded air-sensitive black crystals of (Bi2S2)[AlCl4]. X-ray diffraction on single-crystals revealed a monoclinic structure containing infinite chains infinity 1(Bi2S2) + . These polycations contain bismuth(II,III) and sulfur(-II) atoms, connected by polar covalent Bi-S and Bi-Bi bonds. The assignment of bonds is ambiguous as a distinction between primary and secondary interactions is arbitrary based on interatomic distances. A real-space quantum chemical bonding analysis, including delocalization indices, helped to quantify the interactions and charge distribution, confirming that a simple Lewis formula is inappropriate to describe the polycation
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Implicit learning of purely non-linguistic sequences: the role of Brocas area
The relevance of Brocaâs area to both language and non-linguistic sequence processing is well established. However, manyof the previous fMRI studies on artificial grammar learning use letter sequences as their non-linguistic stimuli. Since theletters are linguistic in nature, these may inadvertently activate language circuits independent of the artificial grammar. Inaddition, participants have been explicitly told before testing that they needed to classify sentences as either grammaticalor ungrammatical. Thus, it is possible that part or all of the activation of Brocaâs reported in these studies is an artifact ofthese manipulations. In our current study, we used sequences of human faces instead of letters, and tested participants insuch a way that they were never aware they were even being tested. Nevertheless, most participants still showed evidenceof learning the non-linguistic artificial grammar, and their Brocaâs area was also differentially active for âgrammaticalâ vs.âungrammaticalâ sequences
Ferromagnetic redshift of the optical gap in GdN
We report measurements of the optical gap in a GdN film at temperatures from
300 to 6K, covering both the paramagnetic and ferromagnetic phases. The gap is
1.31eV in the paramagnetic phase and red-shifts to 0.9eV in the spin-split
bands below the Curie temperature. The paramagnetic gap is larger than was
suggested by very early experiments, and has permitted us to refine a
(LSDA+U)-computed band structure. The band structure was computed in the full
translation symmetry of the ferromagnetic ground state, assigning the
paramagnetic-state gap as the average of the majority- and minority-spin gaps
in the ferromagnetic state. That procedure has been further tested by a band
structure in a 32-atom supercell with randomly-oriented spins. After fitting
only the paramagnetic gap the refined band structure then reproduces our
measured gaps in both phases by direct transitions at the X point.Comment: 5 pages, 4 figure
Qualitative and quantitative demonstration of bead-to-bead transfer with bone marrow-derived human mesenchymal stem cells on microcarriers:utilising the phenomenon to improve culture performance
Human mesenchymal stem cells (hMSCs) are a key candidate for advanced cell therapies with numerous clinical trials investigating their potential to treat acute and chronic indications. However, important translational and manufacturing challenges need to be addressed to improve our capability for scalable production of fully functional cells. In this study, we have demonstrated, both qualitatively and quantitatively, the ability of bone marrow-derived hMSCs to migrate from one microcarrier to another, and, to populate fresh microcarriers when added into suspension culture. Additionally, we have shown that compared to inoculating a culture with cells in free suspension, inoculating 10% of near-confluent microcarriers from an initial seed microcarrier culture resulted in an increase in the cell growth rate and overall cell yield and a significant reduction in the lag phase. These findings were consistent across cells from three different BM-hMSC donors and across different culture medium conditions, foetal bovine serum-supplemented medium, human platelet lysate-supplemented medium and serum-free medium. This new cells-on-beads inoculation method is an effective means of process intensification with the potential to decrease manufacturing times and potentially costs of hMSC-based therapies
Role of neutral evolution in word turnover during centuries of english word popularity
© The Author(s). Here, we test Neutral models against the evolution of English word frequency and vocabulary at the corpus scale, as recorded in annual word frequencies from three centuries of English language books. Against these data, we test both static and dynamic predictions of two neutral models, including the relation between corpus size and vocabulary size, frequency distributions, and turnover within those frequency distributions. Although a commonly used Neutral model fails to replicate all these emergent properties at once, we find that modified two-stage Neutral model does replicate the static and dynamic properties of the corpus data. This two-stage model is meant to represent a relatively small corpus of English books, analogous to a âcanonâ, sampled by an exponentially increasing corpus of books among the wider population of authors. More broadly, this model â a smaller neutral model within a larger neutral model â could represent more broadly those situations where mass attention is focused on a small subset of the cultural variants
Segmenting Motion Capture Data Using a Qualitative Analysis
Many interactive 3D games utilize motion capture for both character animation and user input. These applications require short, meaningful sequences of data. Manually producing these segments of motion capture data is a laborious, time-consuming process that is impractical for real-time applications. We present a method to automatically produce semantic segmentations of general motion capture data by examining the qualitative properties that are intrinsic to all motions, using Laban Movement Analysis (LMA). LMA provides a good compromise between high-level semantic features, which are difficult to extract for general motions, and lowlevel kinematic features, which often yield unsophisticated segmentations. Our method finds motion sequences which exhibit high output similarity from a collection of neural networks trained with temporal variance. We show that segmentations produced using LMA features are more similar to manual segmentations, both at the frame and the segment level, than several other automatic segmentation methods
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