7,999 research outputs found
Strategi Training Within Industry sebagai Upaya Peningkatan Kepercayaan Diri Siswa pada Mata Pelajaran Pengolahan Makanan Kontinental
Practices in Vocational High Schools hold an important role, because through practices, students could master the skills optimally. Confidence is a significant aspect that should be owned by students to conduct the practices. However in the field, there were several students of grade XI Jasa Boga I of SMKN 1 Sewon who had low confidence in the Continental Cuisine Practice. This was indicated by the hesitation of the students in conducting the practices. Every group depended on the teacher' assistance. This action research was conducted in three cycles that consisted of planning, implementation, observation, and reflection. The results of the study showed an improvement of the students' confidence from 2.49 become 2.66 and 2.86 in the subject of Continental Cuisine through Training within Industry Strategy
An exact Coulomb cutoff technique for supercell calculations
We present a new reciprocal space analytical method to cutoff the long range
interactions in supercell calculations for systems that are infinite and
periodic in 1 or 2 dimensions, extending previous works for finite systems. The
proposed cutoffs are functions in Fourier space, that are used as a
multiplicative factor to screen the bare Coulomb interaction. The functions are
analytic everywhere but in a sub-domain of the Fourier space that depends on
the periodic dimensionality. We show that the divergences that lead to the
non-analytical behaviour can be exactly cancelled when both the ionic and the
Hartree potential are properly screened. This technique is exact, fast, and
very easy to implement in already existing supercell codes. To illustrate the
performance of the new scheme, we apply it to the case of the Coulomb
interaction in systems with reduced periodicity (as one-dimensional chains and
layers). For those test cases we address the impact of the cutoff in different
relevant quantities for ground and excited state properties, namely: the
convergence of the ground state properties, the static polarisability of the
system, the quasiparticle corrections in the GW scheme and in the binding
energy of the excitonic states in the Bethe-Salpeter equation. The results are
very promising.Comment: Submitted to Physical Review B on Dec 23rd 200
Bound excitons in time-dependent density-functional-theory: optical and energy-loss spectra
A robust and efficient frequency dependent and non-local exchange-correlation
is derived by imposing time-dependent density-functional
theory (TDDFT) to reproduce the many-body diagrammatic expansion of the
Bethe-Salpeter polarization function. As an illustration, we compute the
optical spectra of LiF, \sio and diamond and the finite momentum transfer
energy-loss spectrum of LiF. The TDDFT results reproduce extremely well the
excitonic effects embodied in the Bethe-Salpeter approach, both for strongly
bound and resonant excitons. We provide a working expression for that
is fast to evaluate and easy to implement.Comment: 4 pages, 2 figures. To appear in Phys. Rev. Let
Driven low density granular mixtures
We study the steady state properties of a 2D granular mixture in the presence
of energy driving by employing simple analytical estimates and Direct
Simulation Monte Carlo. We adopt two different driving mechanisms: a) a
homogeneous heat bath with friction and b) a vibrating boundary (thermal or
harmonic) in the presence of gravity. The main findings are: the appearance of
two different granular temperatures, one for each species; the existence of
overpopulated tails in the velocity distribution functions and of non trivial
spatial correlations indicating the spontaneous formation of cluster
aggregates. In the case of a fluid subject to gravity and to a vibrating
boundary, both densities and temperatures display non uniform profiles along
the direction normal to the wall, in particular the temperature profiles are
different for the two species while the temperature ratio is almost constant
with the height. Finally, we obtained the velocity distributions at different
heights and verified the non gaussianity of the resulting distributions.Comment: 19 pages, 12 figures, submitted for publicatio
Critical properties of Ising model on Sierpinski fractals. A finite size scaling analysis approach
The present paper focuses on the order-disorder transition of an Ising model
on a self-similar lattice. We present a detailed numerical study, based on the
Monte Carlo method in conjunction with the finite size scaling method, of the
critical properties of the Ising model on some two dimensional deterministic
fractal lattices with different Hausdorff dimensions. Those with finite
ramification order do not display ordered phases at any finite temperature,
whereas the lattices with infinite connectivity show genuine critical behavior.
In particular we considered two Sierpinski carpets constructed using different
generators and characterized by Hausdorff dimensions d_H=log 8/log 3 = 1.8927..
and d_H=log 12/log 4 = 1.7924.., respectively.
The data show in a clear way the existence of an order-disorder transition at
finite temperature in both Sierpinski carpets.
By performing several Monte Carlo simulations at different temperatures and
on lattices of increasing size in conjunction with a finite size scaling
analysis, we were able to determine numerically the critical exponents in each
case and to provide an estimate of their errors.
Finally we considered the hyperscaling relation and found indications that it
holds, if one assumes that the relevant dimension in this case is the Hausdorff
dimension of the lattice.Comment: 21 pages, 7 figures; a new section has been added with results for a
second fractal; there are other minor change
Anisotropic excitonic effects in the energy loss function of hexagonal boron nitride
We demonstrate that the valence energy-loss function of hexagonal boron
nitride (hBN) displays a strong anisotropy in shape, excitation energy and
dispersion for momentum transfer q parallel or perpendicular to the hBN layers.
This is manifested by e.g. an energy shift of 0.7 eV that cannot be captured by
single-particle approaches and is a demonstration of a strong anisotropy in the
two-body electron-hole interaction. Furthermore, for in-plane directions of q
we observe a splitting of the -plasmon in the M direction that is absent in the
K direction and this can be traced back to band-structure effects.Comment: 10 pages, 4 figure
SITE SELECTION OF SEAWEED CULTURE USING SPOT AND LANDSAT SATELLITE DATA IN PARI ISLAND
One of several factors for seaweed culture success is to determine the suitable location for seaweed culture based on oceanographic parameters. The best location for seaweed culture is coastal waters with suitable requirements for total suspended solid (TSS), sea surface temperature (SST), and area with calm water that is sheltered from waves, strong current and predator, such as lagoon in the middle of an atoll. The purpose of this study was to locate the suitable area for seaweed culture in Pari island, Seribu island using SPOT and LANDSAT-TM data. The results showed that TSS in Pari island waters were in the range of 150 mg/l - 200 mg/l, SST in the range of 22-29°C, while coral reefs and lagoon was only available in some coastal locations. The analysis showed that most of Pari island waters were suitable for seaweed culture
Interactions Between Kidney Function and Cerebrovascular Disease: Vessel Pathology That Fires Together Wires Together
The kidney and the brain, as high-flow end organs relying on autoregulatory mechanisms, have unique anatomic and physiological hemodynamic properties. Similarly, the two organs share a common pattern of microvascular dysfunction as a result of aging and exposure to vascular risk factors (e.g., hypertension, diabetes and smoking) and therefore progress in parallel into a systemic condition known as small vessel disease (SVD). Many epidemiological studies have shown that even mild renal dysfunction is robustly associated with acute and chronic forms of cerebrovascular disease. Beyond ischemic SVD, kidney impairment increases the risk of acute cerebrovascular events related to different underlying pathologies, notably large artery stroke and intracerebral hemorrhage. Other chronic cerebral manifestations of SVD are variably associated with kidney disease. Observational data have suggested the hypothesis that kidney function influences cerebrovascular disease independently and adjunctively to the effect of known vascular risk factors, which affect both renal and cerebral microvasculature. In addition to confirming this independent association, recent large-scale human genetic studies have contributed to disentangling potentially causal associations from shared genetic predisposition and resolving the uncertainty around the direction of causality between kidney and cerebrovascular disease. Accelerated atherosclerosis, impaired cerebral autoregulation, remodeling of the cerebral vasculature, chronic inflammation and endothelial dysfunction can be proposed to explain the additive mechanisms through which renal dysfunction leads to cerebral SVD and other cerebrovascular events. Genetic epidemiology also can help identify new pathological pathways which wire kidney dysfunction and cerebral vascular pathology together. The need for identifying additional pathological mechanisms underlying kidney and cerebrovascular disease is attested to by the limited effect of current therapeutic options in preventing cerebrovascular disease in patients with kidney impairment
Sequential fissions of heavy nuclear systems
In Xe+Sn central collisions from 12 to 20 MeV/A measured with the INDRA
4 multidetector, the three-fragment exit channel occurs with a significant
cross section. In this contribution, we show that these fragments arise from
two successive binary splittings of a heavy composite system. Strong Coulomb
proximity effects are observed in the three-fragment final state. By comparison
with Coulomb trajectory calculations, we show that the time scale between the
consecutive break-ups decreases with increasing bombarding energy, becoming
compatible with quasi-simultaneous multifragmentation above 18 MeV/A.Comment: 6 pages, 5 figures, contribution to conference proceedings of the
Fifth International Workshop on Nuclear fission and Fission-Product
Spectroscop
Interface pinning and slow ordering kinetics on infinitely ramified fractal structures
We investigate the time dependent Ginzburg-Landau (TDGL) equation for a non
conserved order parameter on an infinitely ramified (deterministic) fractal
lattice employing two alternative methods: the auxiliary field approach and a
numerical method of integration of the equations of evolution. In the first
case the domain size evolves with time as , where is
the anomalous random walk exponent associated with the fractal and differs from
the normal value 2, which characterizes all Euclidean lattices. Such a power
law growth is identical to the one observed in the study of the spherical model
on the same lattice, but fails to describe the asymptotic behavior of the
numerical solutions of the TDGL equation for a scalar order parameter. In fact,
the simulations performed on a two dimensional Sierpinski Carpet indicate that,
after an initial stage dominated by a curvature reduction mechanism \`a la
Allen-Cahn, the system enters in a regime where the domain walls between
competing phases are pinned by lattice defects.
The lack of translational invariance determines a rough free energy
landscape, the existence of many metastable minima and the suppression of the
marginally stable modes, which in translationally invariant systems lead to
power law growth and self similar patterns. On fractal structures as the
temperature vanishes the evolution is frozen, since only thermally activated
processes can sustain the growth of pinned domains.Comment: 16 pages+14 figure
- …