818 research outputs found
Carbon nanotube: a low-loss spin-current waveguide
We demonstrate with a quantum-mechanical approach that carbon nanotubes are
excellent spin-current waveguides and are able to carry information stored in a
precessing magnetic moment for long distances with very little dispersion and
with tunable degrees of attenuation. Pulsed magnetic excitations are predicted
to travel with the nanotube Fermi velocity and are able to induce similar
excitations in remote locations. Such an efficient way of transporting magnetic
information suggests that nanotubes are promising candidates for memory devices
with fast magnetization switchings
X-Ray Detection of Transient Magnetic Moments Induced by a Spin Current in Cu
We have used a MHz lock-in x-ray spectro-microscopy technique to directly
detect changes of magnetic moments in Cu due to spin injection from an adjacent
Co layer. The elemental and chemical specificity of x-rays allows us to
distinguish two spin current induced effects. We detect the creation of
transient magnetic moments of on Cu atoms
within the bulk of the 28 nm thick Cu film due to spin-accumulation. The moment
value is compared to predictions by Mott's two current model. We also observe
that the hybridization induced existing magnetic moments on Cu interface atoms
are transiently increased by about 10% or .
This reveals the dominance of spin-torque alignment over Joule heat induced
disorder of the interfacial Cu moments during current flow
Observation of Precipitation Evolution in Fe-Ni-Mn-Ti-Al Maraging Steel by Atom Probe Tomography
We describe the full decomposition sequence in an Fe-Ni-Mn-Ti-Al maraging steel during isothermal annealing at 550 °C. Following significant pre-precipitation clustering reactions within the supersaturated martensitic solid solution, (Ni,Fe)3Ti and (Ni,Fe)3(Al,Mn) precipitates eventually form after isothermal aging for ~60 seconds. The morphology of the (Ni,Fe)3Ti particles changes gradually during aging from predominantly plate-like to rod-like, and, importantly, Mn and Al were observed to segregate to these precipitate/matrix interfaces. The (Ni,Fe)3(Al,Mn) precipitates occurred at two main locations: uniformly within the matrix and at the periphery of the (Ni,Fe)3Ti particles. We relate this latter mode of precipitation to the Mn-Al segregation
A study on the dynamics of temporary HIV treatment to assess the controversial outcomes of clinical trials: An <em>in-silico</em> approach
MSIS 2006 Curriculum Preview
The MSIS 2000 curriculum is now over 5 years old. That curriculum (the first revisions for the MS program since 1982) was widely adopted by IS departments throughout the world. A committee established jointly by AIS and ACM started working in summer 2003 on revising and updating the MS curriculum based on the experience of the adopting schools. The work is nearing completion. This paper describes the state of the revisions as of April 2005
MSIS 2006: Model Curriculum and Guidelines for Graduate Degree Programs in Information Systems
This article presents the MSIS 2006 Model Curriculum and Guidelines for Graduate Degree Programs in Information Systems. As with MSIS 2000 and its predecessors, the objective is to create a model for schools designing or revising an MS curriculum in Information Systems. The curriculum was designed by a joint committee of the Association for Information Systems and the Association for Computing Machinery. MSIS2006 is a major update of MSIS 2000. Features include increasing the number of required courses from 10 to 12 while revising prerequisites, introducing new courses and revising existing courses to modernize the curriculum, and alternatives for phased upgrading from MSIS2000 to MSIS 2006. As with the previous curriculum, it is the product of detailed consultation with the IS community. The curriculum received the endorsement of 8 major IS professional groups
A Symposium to Mark the Publication, by New York University Press, of Ian O’Donnell’s Prison Life: Pain, Resistance, and Purpose
Recognizing the major scholarly contributions to criminology by the noted Irish criminologist, Ian O’Donnell, The Prison Journal invited seven contemporary corrections and punishment scholars to offer insights into O’Donnell’s new book, Prison Life: Pain, Resistance, and Purpose. Offering contextually rich descriptions of prisoner life, the text features four case study prisons—H Blocks, Northern Ireland; Eastham Unit, Texas; Isir Bet, Ethiopia; and ADX Florence, Colorado, in pivotal time periods and through an individual\u27s custodial career in each institution. The symposium discussants focus on O’Donnell\u27s conceptual framework—the degree of prison integration, system and staff regulation, and legitimacy—and how these reflect the key interactions between punishment and society across time and culture
STM fingerprint of molecule–adatom interactions in a self-assembled metal–organic surface coordination network on Cu(111)
7 páginas, 5 figuras, 3 tablas.-- El pdf del artÃculo es la versión pre-print.A novel approach of identifying metal atoms within a metal–organic surface coordination network using scanning tunnelling microscopy (STM) is presented. The Cu adatoms coordinated in the porous surface network of 1,3,8,10-tetraazaperopyrene (TAPP) molecules on a Cu(111) surface give rise to a characteristic electronic resonance in STM experiments. Using density functional theory calculations, we provide strong evidence that this resonance is a fingerprint of the interaction between the molecules and the Cu adatoms. We also show that the bonding of the Cu adatoms to the organic exodentate ligands is characterised by both the mixing of the nitrogen lone-pair orbitals of TAPP with states on the Cu adatoms and the partial filling of the lowest unoccupied molecular orbital (LUMO) of the TAPP molecule. Furthermore, the key interactions determining the surface unit cell of the network are discussed.This work was financially supported by the European Union
through the Marie Curie Research Training Network
PRAIRIES (MRTN-CT-2006-035810). Support from the
Swiss National Science Foundation, the National Center of
Competence in Research (NCCR) ‘‘Nanoscale Science’’ and
the Wolfermann Naegeli Stiftung is also acknowledged. MP is
also grateful for support from the Swedish Research Council
(VR).Peer reviewe
MSIS 2000: Model Curriculum and Guidelines for Graduate Degree Programs in Information Systems
This article contains the official text of the MSIS 2000 model curriculum as approved by both the Association for Computing Machinery and the Association for Information Systems. It is presented here in its original form
Maturation of mammalian H/ACA box snoRNAs: PAPD5-dependent adenylation and PARN-dependent trimming
Small nucleolar and small Cajal body RNAs (snoRNAs and scaRNAs) of the H/ACA box and C/D box type are generated by exonucleolytic shortening of longer precursors. Removal of the last few nucleotides at the 3' end is known to be a distinct step. We report that, in human cells, knock-down of the poly(A) specific ribonuclease (PARN), previously implicated only in mRNA metabolism, causes the accumulation of oligoadenylated processing intermediates of H/ACA box but not C/D box RNAs. In agreement with a role of PARN in snoRNA and scaRNA processing, the enzyme is concentrated in nucleoli and Cajal bodies. Oligo(A) tails are attached to a short stub of intron sequence remaining beyond the mature 3' end of the snoRNAs. The noncanonical poly(A) polymerase PAPD5 is responsible for addition of the oligo(A) tails. We suggest that deadenylation is coupled to clean 3' end trimming, which might serve to enhance snoRNA stability
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