624 research outputs found
Structural investigations on -FeGe at high pressure and low temperature
The structural parameters of -FeGe have been determined at ambient
conditions using single crystal refinement. Powder diffraction have been
carried out to determine structural properties and compressibility for
pressures up to 30 GPa and temperatures as low as 82 K. The discontinuous
change in the pressure dependence of the shortest Fe-Ge interatomic distance
might be interpreted as a symmetry-conserving transition and seems to be
related to a magnetic phase boundary line.Comment: 4 pages, 5 figure
Electronic and Thermoelectric Properties of RuIn_{3-x}A_{x} (A = Sn, Zn)
Recently, we reported [M. Wagner et al., J. Mater. Res. 26, 1886 (2011)]
transport measurements on the semiconducting intermetallic system RuIn3 and its
substitution derivatives RuIn_{3-x}A_{x} (A = Sn, Zn). Higher values of the
thermoelectric figure of merit (zT = 0.45) compared to the parent compound were
achieved by chemical substitution. Here, using density functional theory based
calculations, we report on the microscopic picture behind the measured
phenomenon. We show in detail that the electronic structure of the substitution
variants of the intermetallic system RuIn_{3-x}A_{x} (A = Sn, Zn) changes in a
rigid-band like fashion. This behavior makes possible the fine tuning of the
substitution concentration to take advantage of the sharp peak-like features in
the density of states of the semiconducting parent compound. Trends in the
transport properties calculated using the semi-classical Boltzmann transport
equations within the constant scattering time approximation are in good
agreement with the former experimental results for RuIn_{3-x}Sn_{x}. Based on
the calculated thermopower for the p-doped systems, we reinvestigated the
Zn-substituted derivative and obtained ZnO-free RuIn_{3-x}Zn_{x}. The new
experimental results are consistent with the calculated trend in thermopower
and yield large zT value of 0.8.Comment: PRB Accepted, 11 pages, 10 figure
A lapa do Bugio
A jazida prĂŠ-histĂłrica do Bugio constitui uma das mais importantes grutas
sepulcrais da faixa estremenha. Encontrava-se intacta Ă data das primeiras
escavaçþes, realizadas em 1957 e 1958. Vicissitudes vårias que motivaram a
dissolução da primeira equipa e favoreceram diversas depredaçþes, entretanto
realizadas, impediram que, antes do recomeço dos trabalhos, em 1966, mesmo
dos materiais recuperados, se pudessem extrair todas as informaçþes neles
potencialmente contidas. Foi possĂvel, a partir do estudo exaustivo do espĂłlio conservado no Museu
de Sesimbra e no recolhido nas escavaçþes de 1966, estabelecer a seguinte
sucessĂŁo cronolĂłgica-cultural:
Primeira ocupação - corresponde talvez à ocupação mais importante,
integrĂĄvel no NeolĂtico recente-final estremenho. Estreitas analogias com o
"horizonte dolmĂŠnico" identificado na vizinha Lapa do Fumo e datado pelo
rĂĄdio-carbono de 3090 Âą 160 a. C. (SERRĂO,1978). A datação realizada no
Bugio deu 2800 Âą 45 a.C.
Segunda ocupação- corresponde muito provavelmente a momento inicial
(ou pleno) do CalcolĂtico, definido pela presença de raros produtos, como o
recipiente de osso recolhido na sep. 7 e "Ădolos" de calcĂĄrio, de osso e marfim.
Terceira ocupação - CalcolĂtico final, campaniforme - representada pelos
Grupos de Palmela e Inciso. Trata-se da ocupação menos importante,
excessivamente valorizada em trabalhos anteriores, talvez pela grande dispersĂŁo
de fragmentos cerâmicos que não ultrapassam, contudo, nove recipientes (alguns
deles representados por apenas um fragmento): taças em calote - (I), de bordo
espessado - (I), de tipo Palmela - (I), caçoilas acampanadas - (2), e vasos
campaniformes - (2), alĂŠm de dois recipientes de tipologia mal definida.Le gisement prĂŠhistorique de Bugio est l 'une des plus importantes grottes
sĂŠpulcrales du littoral de l'EstrĂŠmadure. Elle a ĂŠtĂŠ trouvĂŠe intacte lors des
premières fouilles, rÊalisÊes en 1957 et 1958. Diverses vicissitudes, qui devaient
aboutir à la dissolution de la première Êquipe de fouilleurs et favoriser le pillage
du site, empêchèrent la difusion de toute information avant la reprise des travaux
en 1966, mĂŞme sur le matĂŠriel rĂŠcupĂŠrĂŠ.
A partir de l' ĂŠtude exhaustive du mobilier conservĂŠ au MusĂŠe de Sesimbra
et de celui qui a ĂŠtĂŠ dĂŠcouvert en 1966, on a pu ĂŠtablir les niveaux chronologiques
suivants: Première occupation, peut-être la plus importante, s'intÊgrant dans le
NĂŠolithique rĂŠcent et final de l'EstrĂŠmadure, prĂŠsentant d' ĂŠtroites analogies avec
"l'horizon dolmĂŠnique" identifiĂŠ sur le site voisin de Lapa do Fumo, datĂŠ de
3090 Âą 160 a.C. par radio-carbone (SERRĂO, 1978). La datation obtenue Ă
Bugio est de 2800 Âą 45 a.C..
Seconde occupation, correspondant très probablement à la phase initiale ou
mĂŠdiane du Chalcolithique, dĂŠfinie par de rares productions, comme le rĂŠcipient
en os recueilli dans la sĂŠpulture 7 et les "idoles" en calcaire, en os et en ivoire.
Troisième occupation (Chalcolithique final, Campaniforme) reprÊsentÊe
par les Groupes de Palmela et incisĂŠ. Il s'agit d'une occupation moins importante,
surĂŠvaluĂŠe dans les travaux antĂŠrieurs, peut-ĂŞtre en raison de la grande dispersion
des fragments de cĂŠramiques qui ne correspondaient, cependant, qu'Ă neuf
rĂŠcipients: coupes en calotte (1 ), coupes au bord ĂŠpais (1), coupes de type de
Palmela (1), casseroles en forme de cloche (2), vases campaniformes (2) et deux
rĂŠcipients Ă la typologie mal dĂŠfinie
Guia de coleta de dados de ceratoconjuntivite bovina infecciosa (CBI).
Monitoramento de surtos; Registro dos dados nas tabelas; Registro fotogrĂĄfico; Coleta de material para anĂĄlises microbiolĂłgicasbitstream/item/176394/1/Documentos-149.pd
Field-induced transition within the superconducting state of CeRh2As2
Funding: We acknowledge funding from the Physics of Quantum Materials department and the research group âPhysics of Unconventional Metals and Superconductors (PUMAS)â of the Max Planck Society. C.G. and E.H. acknowledge support from the German Science Foundation (DFG) through grant GE 602/4-1 Fermi-NESt. P.M.R.B. was supported by the Marsden Fund Council from Government funding, managed by Royal Society Te ApÄrangi. R.K. is supported by the DFG through project. no. KU 3287/1-1. D.F.A. was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under award DE-SC0021971.Materials with multiple superconducting phases are rare. Here, we report the discovery of two-phase unconventional superconductivity in CeRh2As2 Using thermodynamic probes, we establish that the superconducting critical field of its high-field phase is as high as 14 tesla, even though the transition temperature is only 0.26 kelvin. Furthermore, a transition between two different superconducting phases is observed in a c axis magnetic field. Local inversion-symmetry breaking at the cerium sites enables Rashba spin-orbit coupling alternating between the cerium sublayers. The staggered Rashba coupling introduces a layer degree of freedom to which the field-induced transition and high critical field seen in experiment are likely related.PostprintPostprintPeer reviewe
Utilização de imagens termogråficas para diagnóstico de ceratoconjuntivite infecciosa bovina em animais da raça Hereford.
Resumo.Fernando Flores Cardoso, Daniel Portella Montardo, JosĂŠ Carlos Ferrugem Moraes, Marcos FlĂĄvio Silva Borba, Sandro da Silva Camargo, editores tĂŠcnicos
Chemistry of layered d-metal pnictide oxides and their potential as candidates for new superconductors
Layered d-metal pnictide oxides are a unique class of compounds which
consists of characteristic d-metal pnictide layers and metal oxide layers. More
than 100 of these layered compounds, including the recently discovered Fe-based
superconducting pnictide oxides, can be classified into 9 structure types.
These structure types and the chemical and physical properties of the
characteristic d-metal pnictide layers and metal oxide layers of the layered
d-metal pnictide oxides are reviewed and discussed. Furthermore, possible
approaches to design new superconductors based on these layered d-metal
pnictide oxides are proposed.Comment: 29 pages including 6 tables and 2 figure
Geometric deep learning as a potential tool for antimicrobial peptide prediction
Antimicrobial peptides (AMPs) are components of natural immunity against invading pathogens. They are polymers that fold into a variety of three-dimensional structures, enabling their function, with an underlying sequence that is best represented in a non-flat space. The structural data of AMPs exhibits non-Euclidean characteristics, which means that certain properties, e.g., differential manifolds, common system of coordinates, vector space structure, or translation-equivariance, along with basic operations like convolution, in non-Euclidean space are not distinctly established. Geometric deep learning (GDL) refers to a category of machine learning methods that utilize deep neural models to process and analyze data in non-Euclidean settings, such as graphs and manifolds. This emerging field seeks to expand the use of structured models to these domains. This review provides a detailed summary of the latest developments in designing and predicting AMPs utilizing GDL techniques and also discusses both current research gaps and future directions in the field
Brane-World Gravity
The observable universe could be a 1+3-surface (the "brane") embedded in a
1+3+\textit{d}-dimensional spacetime (the "bulk"), with Standard Model
particles and fields trapped on the brane while gravity is free to access the
bulk. At least one of the \textit{d} extra spatial dimensions could be very
large relative to the Planck scale, which lowers the fundamental gravity scale,
possibly even down to the electroweak ( TeV) level. This revolutionary
picture arises in the framework of recent developments in M theory. The
1+10-dimensional M theory encompasses the known 1+9-dimensional superstring
theories, and is widely considered to be a promising potential route to quantum
gravity. At low energies, gravity is localized at the brane and general
relativity is recovered, but at high energies gravity "leaks" into the bulk,
behaving in a truly higher-dimensional way. This introduces significant changes
to gravitational dynamics and perturbations, with interesting and potentially
testable implications for high-energy astrophysics, black holes, and cosmology.
Brane-world models offer a phenomenological way to test some of the novel
predictions and corrections to general relativity that are implied by M theory.
This review analyzes the geometry, dynamics and perturbations of simple
brane-world models for cosmology and astrophysics, mainly focusing on warped
5-dimensional brane-worlds based on the Randall--Sundrum models. We also cover
the simplest brane-world models in which 4-dimensional gravity on the brane is
modified at \emph{low} energies -- the 5-dimensional Dvali--Gabadadze--Porrati
models. Then we discuss co-dimension two branes in 6-dimensional models.Comment: A major update of Living Reviews in Relativity 7:7 (2004)
"Brane-World Gravity", 119 pages, 28 figures, the update contains new
material on RS perturbations, including full numerical solutions of
gravitational waves and scalar perturbations, on DGP models, and also on 6D
models. A published version in Living Reviews in Relativit
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