2,863 research outputs found
Restorative Justice-Informed Moral Acquaintance: Resolving the Dual Role Problem in Correctional and Forensic Practice
The issue of dual roles within forensic and correctional fields has typically been conceptualized as dissonance—experienced by practitioners— when attempting to adhere to the conflicting ethical requirements associated with client well-being and community protection. In this paper, we argue that the dual role problem should be conceptualized more broadly; to incorporate the relationship between the offender and their victim. We also propose that Restorative Justice (RJ) is able to provide a preliminary ethical framework to deal with this common ethical oversight. Furthermore, we unite the RJ framework with that of Ward’s (2013) moral acquaintance model to provide a more powerful approach—RJ informed moral acquaintance—aimed at addressing the ethical challenges faced by practitioners within forensic and correctional roles
Theory of Scanning Tunneling Spectroscopy of a Magnetic Adatom on a Metallic Surface
A comprehensive theory is presented for the voltage, temperature, and spatial
dependence of the tunneling current between a scanning tunneling microscope
(STM) tip and a metallic surface with an individual magnetic adatom. Modeling
the adatom by a nondegenerate Anderson impurity, a general expression is
derived for a weak tunneling current in terms of the dressed impurity Green
function, the impurity-free surface Green function, and the tunneling matrix
elements. This generalizes Fano's analysis to the interacting case. The
differential-conductance lineshapes seen in recent STM experiments with the tip
directly over the magnetic adatom are reproduced within our model, as is the
rapid decay, \sim 10\AA, of the low-bias structure as one moves the tip away
from the adatom. With our simple model for the electronic structure of the
surface, there is no dip in the differential conductance at approximately one
lattice spacing from the magnetic adatom, but rather we see a resonant
enhancement. The formalism for tunneling into small clusters of magnetic
adatoms is developed.Comment: 12 pages, 9 figures; to appear in Phys. Rev.
Global properties of Stochastic Loewner evolution driven by Levy processes
Standard Schramm-Loewner evolution (SLE) is driven by a continuous Brownian
motion which then produces a trace, a continuous fractal curve connecting the
singular points of the motion. If jumps are added to the driving function, the
trace branches. In a recent publication [1] we introduced a generalized SLE
driven by a superposition of a Brownian motion and a fractal set of jumps
(technically a stable L\'evy process). We then discussed the small-scale
properties of the resulting L\'evy-SLE growth process. Here we discuss the same
model, but focus on the global scaling behavior which ensues as time goes to
infinity. This limiting behavior is independent of the Brownian forcing and
depends upon only a single parameter, , which defines the shape of the
stable L\'evy distribution. We learn about this behavior by studying a
Fokker-Planck equation which gives the probability distribution for endpoints
of the trace as a function of time. As in the short-time case previously
studied, we observe that the properties of this growth process change
qualitatively and singularly at . We show both analytically and
numerically that the growth continues indefinitely in the vertical direction
for , goes as for , and saturates for . The probability density has two different scales corresponding to
directions along and perpendicular to the boundary. In the former case, the
characteristic scale is . In the latter case the scale
is for , and
for . Scaling functions for the probability density are given for
various limiting cases.Comment: Published versio
Theory for Electron-Doped Cuprate Superconductors: d-wave symmetry order parameter
Using as a model the Hubbard Hamiltonian we determine various basic
properties of electron-doped cuprate superconductors like
and for a
spin-fluctuation-induced pairing mechanism. Most importantly we find a narrow
range of superconductivity and like for hole-doped cuprates -
symmetry for the superconducting order parameter. The superconducting
transition temperatures for various electron doping concentrations
are calculated to be much smaller than for hole-doped cuprates due to the
different Fermi surface and a flat band well below the Fermi level. Lattice
disorder may sensitively distort the symmetry via
electron-phonon interaction
Spin-orbit Scattering and the Kondo Effect
The effects of spin-orbit scattering of conduction electrons in the Kondo
regime are investigated theoretically. It is shown that due to time-reversal
symmetry, spin-orbit scattering does not suppress the Kondo effect, even though
it breaks spin-rotational symmetry, in full agreement with experiment. An
orbital magnetic field, which breaks time-reversal symmetry, leads to an
effective Zeeman splitting, which can be probed in transport measurements. It
is shown that, similar to weak-localization, this effect has anomalous magnetic
field and temperature dependence.Comment: 10 pages, RevTex, one postscript figure available on request from
[email protected]
Calculations of the Knight Shift Anomalies in Heavy Electron Materials
We have studied the Knight shift and magnetic susceptibility
of heavy electron materials, modeled by the infinite U Anderson model
with the NCA method. A systematic study of and for
different Kondo temperatures (which depends on the hybridization width
) shows a low temperature anomaly (nonlinear relation between and
) which increases as the Kondo temperature and distance
increase. We carried out an incoherent lattice sum by adding the of
a few hundred shells of rare earth atoms around a nucleus and compare the
numerically calculated results with the experimental results. For CeSn_3, which
is a concentrated heavy electron material, both the ^{119}Sn NMR Knight shift
and positive muon Knight shift are studied. Also, lattice coherence effects by
conduction electron scattering at every rare earth site are included using the
average-T matrix approximation. Also NMR Knight shifts for YbCuAl and the
proposed quadrupolar Kondo alloy Y_{0.8}U_{0.2}Pd_{3} are studied.Comment: 31 pages of RevTex, 22 Postscript figures, submmitted to PRB, some
figures are delete
The polo-like kinase 1 (PLK1) inhibitor NMS-P937 is effective in a new model of disseminated primary CD56+ acute monoblastic leukaemia
CD56 is expressed in 15–20% of acute myeloid leukaemias (AML) and is associated with extramedullary diffusion, multidrug resistance and poor prognosis. We describe the establishment and characterisation of a novel disseminated model of AML (AML-NS8), generated by injection into mice of leukaemic blasts freshly isolated from a patient with an aggressive CD56+ monoblastic AML (M5a). The model reproduced typical manifestations of this leukaemia, including presence of extramedullary masses and central nervous system involvement, and the original phenotype, karyotype and genotype of leukaemic cells were retained in vivo. Recently Polo-Like Kinase 1 (PLK1) has emerged as a new candidate drug target in AML. We therefore tested our PLK1 inhibitor NMS-P937 in this model either in the engraftment or in the established disease settings. Both schedules showed good efficacy compared to standard therapies, with a significant increase in median survival time (MST) expecially in the established disease setting (MST = 28, 36, 62 days for vehicle, cytarabine and NMS-P937, respectively). Importantly, we could also demonstrate that NMS-P937 induced specific biomarker modulation in extramedullary tissues. This new in vivo model of CD56+ AML that recapitulates the human tumour lends support for the therapeutic use of PLK1 inhibitors in AML
Scanning tunneling spectroscopy of high-temperature superconductors
Tunneling spectroscopy played a central role in the experimental verification
of the microscopic theory of superconductivity in the classical
superconductors. Initial attempts to apply the same approach to
high-temperature superconductors were hampered by various problems related to
the complexity of these materials. The use of scanning tunneling
microscopy/spectroscopy (STM/STS) on these compounds allowed to overcome the
main difficulties. This success motivated a rapidly growing scientific
community to apply this technique to high-temperature superconductors. This
paper reviews the experimental highlights obtained over the last decade. We
first recall the crucial efforts to gain control over the technique and to
obtain reproducible results. We then discuss how the STM/STS technique has
contributed to the study of some of the most unusual and remarkable properties
of high-temperature superconductors: the unusual large gap values and the
absence of scaling with the critical temperature; the pseudogap and its
relation to superconductivity; the unprecedented small size of the vortex cores
and its influence on vortex matter; the unexpected electronic properties of the
vortex cores; the combination of atomic resolution and spectroscopy leading to
the observation of periodic local density of states modulations in the
superconducting and pseudogap states, and in the vortex cores.Comment: To appear in RMP; 65 pages, 62 figure
Extremely long quasiparticle spin lifetimes in superconducting aluminium using MgO tunnel spin injectors
There has been an intense search in recent years for long-lived
spin-polarized carriers for spintronic and quantum-computing devices. Here we
report that spin polarized quasi-particles in superconducting aluminum layers
have surprisingly long spin-lifetimes, nearly a million times longer than in
their normal state. The lifetime is determined from the suppression of the
aluminum's superconductivity resulting from the accumulation of spin polarized
carriers in the aluminum layer using tunnel spin injectors. A Hanle effect,
observed in the presence of small in-plane orthogonal fields, is shown to be
quantitatively consistent with the presence of long-lived spin polarized
quasi-particles. Our experiments show that the superconducting state can be
significantly modified by small electric currents, much smaller than the
critical current, which is potentially useful for devices involving
superconducting qubits
Gate-tunable black phosphorus spin valve with nanosecond spin lifetimes
Two-dimensional materials offer new opportunities for both fundamental
science and technological applications, by exploiting the electron spin. While
graphene is very promising for spin communication due to its extraordinary
electron mobility, the lack of a band gap restricts its prospects for
semiconducting spin devices such as spin diodes and bipolar spin transistors.
The recent emergence of 2D semiconductors could help overcome this basic
challenge. In this letter we report the first important step towards making 2D
semiconductor spin devices. We have fabricated a spin valve based on ultra-thin
(5 nm) semiconducting black phosphorus (bP), and established fundamental spin
properties of this spin channel material which supports all electrical spin
injection, transport, precession and detection up to room temperature (RT).
Inserting a few layers of boron nitride between the ferromagnetic electrodes
and bP alleviates the notorious conductivity mismatch problem and allows
efficient electrical spin injection into an n-type bP. In the non-local spin
valve geometry we measure Hanle spin precession and observe spin relaxation
times as high as 4 ns, with spin relaxation lengths exceeding 6 um. Our
experimental results are in a very good agreement with first-principles
calculations and demonstrate that Elliott-Yafet spin relaxation mechanism is
dominant. We also demonstrate that spin transport in ultra-thin bP depends
strongly on the charge carrier concentration, and can be manipulated by the
electric field effect
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