317 research outputs found
PENGEMBANGAN PROGRAM PENGAJARAN BAHASA INDONESIA SEBAGAI BAHASA ASING PADA JURUSAN PENDIDIKAN BAHASA DAN SASTRA INDONESIA, FAKULTAS BAHASA DAN SENI UNIVERSITAS NEGERI YOGYAKARTA
Tujuan jangka panjang dari penelitian ini adalah melakukan pengembangan desain instruksional bagi a) Paket Program PBIPA bagi calon guru Bahasa Indonesia sebagai Bahasa Asing dan b) Paket Program Pengajaran BIPA dan membina jejaring dengan rekanan dalam dan luar negeri yang berminat terhadap pengembangan pengajaran bahasa dan budaya Indonesia. Target khusus yang akan dicapai dikaitkan dengan Kurikulum FBS UNY 2002, bahwa (1) Paket Program PBIPA merupakan paket pilihan yang berdiri sendiri dan kelulusannya diberikan sertifikat terpisah dari transkrip program S1 dan akan dibuka untuk mahasiswa Jurusan Bahasa Indonesia atau non-bahasa Indonesia. Karenanya, perlu dilakukan studi: i) desain instruksional dan beberapa aspeknya, ii) sosialisasi paket pada mahasiswa dan rekanan yang memerlukan lulusan program Paket Pengajaran PBIA, dan iii) melakukan penelitian perbaikan pengajaran untuk semua mata kuliah dalam Paket Pengajaran PBIA; (2) Paket Pengajaran BIPA akan ditekankan pada: i) penyusunan kurikulum bagi program in country 3 atau 6 bulan, pengajaran BIPA bagi keperluan khusus (Indonesian for Specific Purposes), dan penyusunan modul pembelajaran; ii) pembentukan jejaring dan kerjasama dengan universitas di luar negeri yang berminat terhadap pembelajaran bahasa dan budaya Indonesia, dan iii) membina kolaborasi dengan rekanan yang dimungkinkan terlibat dalam pelaksanaan Paket Pengajaran BIPA. Metode yang dipakai disesuaikan dengan tujuan pengembangan, antara lain: survei, observasional, dan berbagai metode yang dipakai dalam research-based teaching. Hasil penelitian ialah sebagai berikut. Dalam rancangan kurikulum 2007, program PBIPA diintegralkan dengan jumlah 144 sks. Hal ini berbeda dengan rancangan semula, yaitu memisahkan program PBIPA dari jumlah 144 sks. Pengintegralan ini sejalan dengan salah satu program I-MHERE, yaitu perintisan Jurusan PBSI menjadi program studi yang bertaraf internasional. Salah satunya ialah dengan memasuk-kan program PBIPA dalam kurikulum 2007 sebagai bagian yang integral dari jumlah 144 sks. Oleh karena hal tersebut, program ini untuk sementara waktu belum dapat dibuka untuk jurusan non PBSI. Silabus telah direvisi berdasarkan angket dan wawancara yang ditujukan kepada pihak-pihak (dosen) yang terlibat BIPA. Berdasarkan silabus yang telah direvisi ini dibuat tujuh modul yang akan diujicobakan pada tahap selanjutnya. Sosialisasi program PBIPA telah dilakukan secara nonformal kepada mahasiswa. Sosialisasi program ini secara formal baru akan dilakukan setelah kurikulum 2007 selesai dibuat. FBS, 2007 (PEND. BHS & SASTRA INDONESIA
3C454.3 reveals the structure and physics of its 'blazar zone'
Recent multi-wavelength observations of 3C454.3, in particular during its
giant outburst in 2005, put severe constraints on the location of the 'blazar
zone', its dissipative nature, and high energy radiation mechanisms. As the
optical, X-ray, and millimeter light-curves indicate, significant fraction of
the jet energy must be released in the vicinity of the millimeter-photosphere,
i.e. at distances where, due to the lateral expansion, the jet becomes
transparent at millimeter wavelengths. We conclude that this region is located
at ~10 parsecs, the distance coinciding with the location of the hot dust
region. This location is consistent with the high amplitude variations observed
on ~10 day time scale, provided the Lorentz factor of a jet is ~20. We argue
that dissipation is driven by reconfinement shock and demonstrate that X-rays
and gamma-rays are likely to be produced via inverse Compton scattering of
near/mid IR photons emitted by the hot dust. We also infer that the largest
gamma-to-synchrotron luminosity ratio ever recorded in this object - having
taken place during its lowest luminosity states - can be simply due to weaker
magnetic fields carried by a less powerful jet.Comment: 19 pages, 3 figures, accepted for publication in Ap
Kink instabilities in jets from rotating magnetic fields
We have performed 2.5D and 3D simulations of conical jets driven by the
rotation of an ordered, large-scale magnetic field in a stratified atmosphere.
The simulations cover about three orders of magnitude in distance to capture
the centrifugal acceleration as well as the evolution past the Alfven surface.
We find that the jets develop kink instabilities, the characteristics of which
depend on the velocity profile imposed at the base of the flow. The
instabilities are especially pronounced with a rigid rotation profile, which
induces a shearless magnetic field. The jet's expansion appears to be limiting
the growth of Alfven mode instabilities.Comment: 10 pages, 13 figures, accepted for publication in A&
Structure and Stability of Keplerian MHD Jets
MHD jet equilibria that depend on source properties are obtained using a
simplified model for stationary, axisymmetric and rotating magnetized outflows.
The present rotation laws are more complex than previously considered and
include a Keplerian disc. The ensuing jets have a dense, current-carrying
central core surrounded by an outer collar with a return current. The
intermediate part of the jet is almost current-free and is magnetically
dominated. Most of the momentum is located around the axis in the dense core
and this region is likely to dominate the dynamics of the jet. We address the
linear stability and the non-linear development of instabilities for our models
using both analytical and 2.5-D numerical simulation's. The instabilities seen
in the simulations develop with a wavelength and growth time that are well
matched by the stability analysis. The modes explored in this work may provide
a natural explanation for knots observed in astrophysical jets.Comment: 35 pages, accepted by the Ap
Cosine and Sine Operators Related with Orthogonal Polynomial Sets on the Intervall [-1,1]
The quantization of phase is still an open problem. In the approach of
Susskind and Glogower so called cosine and sine operators play a fundamental
role. Their eigenstates in the Fock representation are related with the
Chebyshev polynomials of the second kind. Here we introduce more general cosine
and sine operators whose eigenfunctions in the Fock basis are related in a
similar way with arbitrary orthogonal polynomial sets on the intervall [-1,1].
To each polynomial set defined in terms of a weight function there corresponds
a pair of cosine and sine operators. Depending on the symmetry of the weight
function we distinguish generalized or extended operators. Their eigenstates
are used to define cosine and sine representations and probability
distributions. We consider also the inverse arccosine and arcsine operators and
use their eigenstates to define cosine-phase and sine-phase distributions,
respectively. Specific, numerical and graphical results are given for the
classical orthogonal polynomials and for particular Fock and coherent states.Comment: 1 tex-file (24 pages), 11 figure
Physical properties of the jet in 0836+710 revealed by its transversal structure
Studying the internal structure of extragalactic jets is crucial for
understanding their physics. The Japanese-led space VLBI project VSOP has
presented an opportunity for such studies, by reaching baseline lengths of up
to 36,000 km and resolving structures down to an angular size of
mas at 5 GHz. VSOP observations of the jet in 0836+710 at 1.6 and 5 GHz have
enabled tracing of the radial structure of the flow on scales from 2 mas to 200
mas along the jet and determination of the wavelengths of individual
oscillatory modes responsible for the formation of the structure observed. We
apply linear stability analysis to identify the oscillatory modes with modes of
Kelvin-Helmholtz instability that match the wavelengths of the structures
observed. We find that the jet structure in 0836+710 can be reproduced by the
helical surface mode and a combination of the helical and elliptic body modes
of Kelvin-Helmholtz instability. Our results indicate that the jet is
substantially stratified and different modes of the instability grow inside the
jet at different distances to the jet axis. The helical surface mode can be
driven externally, and we discuss the implications of the driving frequency on
the physics of the active nucleus in 0836+710.Comment: Accepted for publication in Astronomy & Astrophysics Letter
Bendings of radio jets in BL Lacertae objects I: EVN and MERLIN observations
Several blazars, and BL Lac objects in particular, show a misalignment
between the jet orientation on parsec and kiloparsec scales. Some authors (i.e.
Conway & Murphy, 1993) have attempted to explain this behaviour invoking
helical jets for misalignment angles around 90\degr, showing how in this case
there are interesting implications for the understanding of the medium into
which the jet is expanding. By comparing sensitive VLA observations (Cassaro et
al., 1999) with images available in the literature for the BL Lac objects from
the 1-Jy Sample (Stickel et al., 1991), it is clear that there is a wide range
of misalignments between the initial jet direction and the kpc-scale jet, when
detected. We have carried out VLBI observations of these BL Lac objects, in
order to investigate the spatial evolution of the radio jets from few tens to
hundreds of mas, and to search for helical jets in this class of sources. We
present here the first dataset obtained from EVN+MERLIN observations at 5 GHz
for seven objects. From these observations we never have a clear detection of
helical jets, we only have a possible signature of their presence in 2 objects.
In only one of the sources with a misalignment angle around 90\degr the
presence of helical jets can be ruled out. This implies that it is not possible
to invoke helical jets to explain the morphology of all the sources showing a
misalignment of about 90\degr between the parsec and the kiloparsec scale
jets.Comment: 12 pages, 9 figures, latex, accepted by Astronomy & Astrophysic
A Sample of Low Redshift BL Lacs. I. The Radio Data
We present a new sample of 30 nearby (z<0.2) BL Lacs, selected to study the
nuclear as well as the large scale properties of low power radio sources. In
this first paper, we show and discuss new radio data taken with the VLA (19
objects at 1.4 GHz, either in A or C configuration, or both) as well as with
the VLBA (15 sources at 5 GHz). On the kiloparsec scale, all objects exhibit a
compact core and a variety of radio morphologies (jets, halos, secondary
compact components). On the parsec scale, we find weak cores and a few short,
one-sided, jets. From the jet/counter-jet ratio, core dominance, and
synchrotron self Compton model we estimate the intrinsic orientation and
velocity of the jets. The resulting properties of BL Lacs are similar to those
of a parent population composed of FR I radio galaxies.Comment: 46 pages, 12 figures, accepted for publication in Ap
Imaging nonequilibrium atomic vibrations with x-ray diffuse scattering
For over a century, x-ray scattering has been the most powerful tool for
determining the equilibrium structure of crystalline materials. Deviations from
perfect periodicity, for example due to thermal motion of the atoms, reduces
the intensity of the Bragg peaks as well as produces structure in the diffuse
scattering background. Analysis of the thermal diffuse scattering (TDS) had
been used to determine interatomic force constants and phonon dispersion in
relatively simple cases before inelastic neutron scattering became the
preferred technique to study lattice dynamics. With the advent of intense
synchrotron x-ray sources, there was a renewed interest in TDS for measuring
phonon dispersion. The relatively short x-ray pulses emanating from these
sources also enables the measurement of phonon dynamics in the time domain.
Prior experiments on nonequilibrium phonons were either limited by
time-resolution and/or to relatively long wavelength excitations. Here we
present the first images of nonequilibrium phonons throughout the Brillouin
zone in photoexcited III-V semiconductors, indium-phosphide and
indium-antimonide, using picosecond time-resolved diffuse scattering. In each
case, we find that the lattice remain out of equilibrium for several hundred
picoseconds up to nanoseconds after laser excitation. The non-equilibrium
population is dominated by transverse acoustic phonons which in InP are
directed along high-symmetry directions. The results have wide implications for
the detailed study of electron-phonon and phonon-phonon coupling in solids.Comment: 10 pages, 3 figure
Waves and Instabilities in Accretion Disks: MHD Spectroscopic Analysis
A complete analytical and numerical treatment of all magnetohydrodynamic
waves and instabilities for radially stratified, magnetized accretion disks is
presented. The instabilities are a possible source of anomalous transport.
While recovering results on known hydrodynamicand both weak- and strong-field
magnetohydrodynamic perturbations, the full magnetohydrodynamic spectra for a
realistic accretion disk model demonstrates a much richer variety of
instabilities accessible to the plasma than previously realized. We show that
both weakly and strongly magnetized accretion disks are prone to strong
non-axisymmetric instabilities.The ability to characterize all waves arising in
accretion disks holds great promise for magnetohydrodynamic spectroscopic
analysis.Comment: FOM-Institute for plasma physics "Rijnhuizen", Nieuwegein, the
Netherlands 12 pages, 3 figures, Accepted for publication in ApJ
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