1,551 research outputs found
Mediation effect of students’ perception of accounting on the relationship between game-based learning and learning approaches
This study explores the mediation effect of students’ perceptions toward accounting to enhance their adoption of the deep learning approach. We adopt game-based learning (GBL) using a self-developed LEGO® simulation game as the active learning material. Participants of this study comprised undergraduate students majoring in accounting from a northern university in Italy. This study contributes to the literature by providing several new insights. First, we present statistical evidence of a mediation effect of students’ perceptions toward accounting on their learning approach, although the course offers a short-time activity. Second, we did not confirm the significance of students’ strong image of conformity in accounting as a mediator in the relationship between GBL and a surface approach to learning. We interpret that students hold more favorable images of conformity to accounting than before taking the GBL course, possibly fostering them to engage with deep approach processes while adopting appropriate facilitation of active learning
A spin metal-oxide-semiconductor field-effect transistor using half-metallic-ferromagnet contacts for the source and drain
We propose and theoretically analyze a novel metal-oxide-semiconductor
field-effect-transistor (MOSFET) type of spin transistor (hereafter referred to
as a spin MOSFET) consisting of a MOS gate structure and
half-metallic-ferromagnet (HMF) contacts for the source and drain. When the
magnetization configuration between the HMF source and drain is parallel
(antiparallel), highly spin-polarized carriers injected from the HMF source to
the channel are transported into (blocked by) the HMF drain, resulting in the
magnetization-configuration-dependent output characteristics. Our
two-dimensional numerical analysis indicates that the spin MOSFET exhibits high
(low) current drive capability in the parallel (antiparallel) magnetization,
and that extremely large magnetocurrent ratios can be obtained. Furthermore,
the spin MOSFET satisfies other important requirements for "spintronic"
integrated circuits, such as high amplification capability, low power-delay
product, and low off-current.Comment: 5 pages, 3 figure
Magneto-optical properties of a new group-IV ferromagnetic semiconductor Ge1-xFex grown by low-temperature molecular beam epitaxy
A new group-IV ferromagnetic semiconductor, Ge1-xFex, was successfully grown
by low-temperature molecular beam epitaxy (LT-MBE) without precipitation of
ferromagnetic Ge-Fe intermetallic compounds. The ferromagnetism of Ge1-xFex
films was investigated by magnetic circular dichroism (MCD). In particular, the
influence of the Fe content (FFe/FGe =1 - 10%) and growth temperature (100,
200OC) on the ferromagnetism was carefully studied. The MCD measurements
revealed that the band structure of the Ge1-xFex films was identical with that
of bulk Ge, and that the large spin splitting of the band structure was induced
by the incorporation of Fe atoms into the Ge matrix, indicating the existence
of s,p-d exchange interactions. The Ge1-xFex films showed ferromagnetic
behavior and the ferromagnetic transition temperature linearly increased with
increasing the Fe composition. These results indicate that the epitaxially
grown Ge1-xFex is an intrinsic ferromagnetic semiconductor.Comment: 15 pages, 4 figures. to appear in J. Appl. Phy
Relativistic Hartree approach with exact treatment of vacuum polarization for finite nuclei
We study the relativistic Hartree approach with the exact treatment of the
vacuum polarization in the Walecka sigma-omega model. The contribution from the
vacuum polarization of nucleon-antinucleon field to the source term of the
meson fields is evaluated by performing the energy integrals of the Dirac Green
function along the imaginary axis. With the present method of the vacuum
polarization in finite system, the total binding energies and charge radii of
16O and 40Ca can be reproduced. On the other hand, the level-splittings in the
single-particle level, in particular the spin-orbit splittings, are not
described nicely because the inclusion of vacuum effect provides a large
effective mass with small meson fields. We also show that the derivative
expansion of the effective action which has been used to calculate the vacuum
contribution for finite nuclei gives a fairly good approximation.Comment: 15 pages, 8 figure
Structure and magnetism of self-organized Ge(1-x)Mn(x) nano-columns
We report on the structural and magnetic properties of thin Ge(1-x)Mn(x)films
grown by molecular beam epitaxy (MBE) on Ge(001) substrates at temperatures
(Tg) ranging from 80deg C to 200deg C, with average Mn contents between 1 % and
11 %. Their crystalline structure, morphology and composition have been
investigated by transmission electron microscopy (TEM), electron energy loss
spectroscopy and x-ray diffraction. In the whole range of growth temperatures
and Mn concentrations, we observed the formation of manganese rich
nanostructures embedded in a nearly pure germanium matrix. Growth temperature
mostly determines the structural properties of Mn-rich nanostructures. For low
growth temperatures (below 120deg C), we evidenced a two-dimensional spinodal
decomposition resulting in the formation of vertical one-dimensional
nanostructures (nanocolumns). Moreover we show in this paper the influence of
growth parameters (Tg and Mn content) on this decomposition i.e. on nanocolumns
size and density. For temperatures higher than 180deg C, we observed the
formation of Ge3Mn5 clusters. For intermediate growth temperatures nanocolumns
and nanoclusters coexist. Combining high resolution TEM and superconducting
quantum interference device magnetometry, we could evidence at least four
different magnetic phases in Ge(1-x)Mn(x) films: (i) paramagnetic diluted Mn
atoms in the germanium matrix, (ii) superparamagnetic and ferromagnetic low-Tc
nanocolumns (120 K 400 K) and
(iv) Ge3Mn5 clusters.Comment: 10 pages 2 colonnes revTex formatte
Towards a global model of accounting education
Purpose - The purpose of this paper is to examine the accounting education systems in three countries - Australia, Japan and Sri Lanka - to inform the development and testing (by application) of a Global Model of Accounting Education
Spin-glass-like behavior of Ge:Mn
We present a detailed study of the magnetic properties of
low-temperature-molecular-beam-epitaxy grown Ge:Mn dilute magnetic
semiconductor films. We find strong indications for a frozen state of
Ge_{1-x}Mn_{x}, with freezing temperatures of T_f=12K and T_f=15K for samples
with x=0.04 and x=0.2, respectively, determined from the difference between
field-cooled and zero-field-cooled magnetization. For Ge_{0.96}Mn_{0.04}, ac
susceptibility measurements show a peak around T_f, with the peak position T'_f
shifting as a function of the driving frequency f by Delta T_f' / [T_f' Delta
log f] ~ 0.06, whereas for sample Ge_{0.8}Mn_{0.2} a more complicated behavior
is observed. Furthermore, both samples exhibit relaxation effects of the
magnetization after switching the magnitude of the external magnetic field
below T_f which are in qualitative agreement with the field- and
zero-field-cooled magnetization measurements. These findings consistently show
that Ge:Mn exhibits a frozen magnetic state at low temperatures and that it is
not a conventional ferromagnet.Comment: Revised version contains extended interpretation of experimental dat
Anti-tumor and anti-angiogenic activity of novel hydantoin derivatives: Inhibition of VEGF secretion in liver metastatic osteosarcoma cells
A series of new azaspiro bicyclic hydantoin derivatives has been designed and synthesized. Initially, the anti-proliferative effect of the hydantoin derivatives was evaluated against human ovarian cancer cells (SKOV-3 and OVSAHO) and murine osteosarcoma cells (LM8 and LM8G7). Among the tested compounds, 8-(3-fluorobenzyl)-1′-(4-(methylsulfonyl)benzyl)-8-azaspiro[bicyclo[3.2.1]octane-3,4′-imidazolidine]-2′,5′-dione (7h) and 8-(3,4-difluorobenzyl)-1′-(4-(methylsulfonyl)benzyl)-8-azaspiro[bicyclo[3.2.1]octane-3,4′-imidazolidine]-2′,5′-dione (7i) showed a significant anti-proliferative activity against the OVSAHO and LM8G7 cells. The real-time monitoring of the effect of the compounds 7h and 7i against the proliferation of LM8G7 was revealed that resulting IC50 values were 102 μM and 13 μM, respectively. We reasoned that the presence of fluorine atom at the 3rd position of the phenyl ring of the hydantoin side chain may determine the potency of the molecule. Furthermore, the compound 7i inhibited the tube formation of the mouse endothelial cells. Finally, the treatment of the compound 7i against the proliferation of LM8G7 cells demonstrated the down regulation of the secretion of VEGF, indicate the potential angioinhibitory effects. In conclusion, our findings demonstrate the suppression of the secretion of VEGF by LM8G7 cells by the compound 7i might contribute at least in part to the antitumor action
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