7,993 research outputs found
Partisipasi Masyarakat dalam Pembangunan melalui Ruang Virtual dan Ruang Nyata
: This study aimed to describe and analyze the community participation in the development of the Salatiga city through information technology. By using the descriptive qualitative approach to observe the formation of community Kabar Salatiga. From the results in the field was found that the formation of community Kabar Salatiga not separated from the role of actor. Actor as agents of change utilize the social media (facebook) so that people can participate to gives information in criticizing, voice their opinions about the Salatiga city's development which currently and has already run. Kabar Salatiga community participation in the development not only manifested through the information provided by the virtual community. The passage of time the actors forming / creating real community of Kabar Salatiga by doing positive activities like helping people who are not able etc. With the community participation in development through information technology is expected the community no longer as an object but a subject.
Keywords: The Role of Actors, Virtual Space, Space Real, developmen
Red Quasars and Quasar Evolution: the Case of BALQSO FIRST J155633.8+351758
We present the first near-IR spectroscopy of the z=1.5 radio-loud BALQSO
FIRST J155633.8+351758. Both the Balmer decrement and the slope of the
rest-frame UV-optical continuum independently suggest a modest amount of
extinction along the line of sight to the BLR (E(B-V)~0.5 for SMC-type screen
extinction at the QSO redshift). The implied gas column density along the line
of sight is much less than is implied by the weak X-ray flux of the object,
suggesting that either the BLR and BAL region have a low dust-to-gas ratio, or
that the rest-frame optical light encounters significantly lower mean column
density lines of sight than the X-ray emission. From the rest-frame UV-optical
spectrum, we are able to constrain the stellar mass content of the system.
Comparing the maximal stellar mass with the black hole mass estimated from the
bolometric luminosity of the QSO, we find that the ratio of the black hole to
stellar mass may be comparable to the Magorrian value, which would imply that
the Magorrian relation is already in place at z=1.5. However, multiple factors
favor a much larger black hole to stellar mass ratio. This would imply that if
the Magorrian relation characterizes the late history of QSOs, and the
situation observed for F1556+3517 is typical of the early evolutionary history
of QSOs, central black hole masses develop more rapidly than bulge masses.
[ABRIDGED]Comment: 23 pages, 4 embedded postscript figures; Accepted for publication in
The Astronomical Journal, December 200
Confinement induced three-dimensional trajectories of microswimmers in rectangular channels
We study the trajectories of a model microorganism inside three-dimensional
channels with square and rectangular cross-sections. Using (i) numerical
simulations based on lattice-Boltzmann method, and (ii) analytical expressions
using far-field hydrodynamic approximations and method of images we
systematically investigate the role of the strength and finite-size of the
squirmer, confinement dimensions, and initial conditions in determining the
three dimensional trajectories of microswimmers. Our results indicate that the
hydrodynamic interactions with the confining walls of the channel significantly
affect the swimming speed and trajectory of the model microswimmer.
Specifically, pullers always display sliding motion inside the channel: weak
pullers slide through the channel centerline, while strong pullers slide
through a path close to any of the walls. Pushers generally follow helical
motion in a square channel. Unlike pullers and pushers, the trajectories of
neutral swimmers are not easy to generalize, and are sensitive to the initial
conditions. Despite this diversity in the trajectories, the far-field
expressions capture the essential features of channel-confined swimmers.
Finally, we propose a method based on the principle of superposition to
understand the origin of the three-dimensional trajectories of channel confined
swimmers. Such construction allows us to predict and justify the origin of
apparently complex 3D trajectories generated by different types of swimmers in
channels with square and rectangular cross sections
Neutrinos in flat extra dimension: towards a realistic scenario
We consider the simple extension of the Standard Model in which an additional
right handed neutrino propagates along a flat extra dimension, while the
Standard Model fields are confined on a 3-brane. The fifth dimension is
orbifold compactified. In this scenario, the neutrino mass can be
naturally suppressed. By studying systematically the fundamental parameter
space, we show that the strong phenomenological constraints on mixing angles
between active and sterile neutrinos (especially those derived from the SNO
experiment data) do not conflict with the possibility of generating a realistic
neutrino mass spectrum. As a second step, we explore the possibility of a
successful leptogenesis through the decays of the Kaluza-Klein excitations of
the right handed neutrino.Comment: 16 pages, 2 ps figure
First Results from the Large Area Lyman Alpha Survey
We report on a new survey for z=4.5 Lyman alpha sources, the Large Area Lyman
Alpha (LALA) survey. Our survey achieves an unprecedented combination of volume
and sensitivity by using narrow-band filters on the new 8192x8192 pixel CCD
Mosaic Camera at the 4 meter Mayall telescope of Kitt Peak National
Observatory.
Well-detected sources with flux and equivalent width matching known high
redshift Lyman alpha galaxies (i.e., observed equivalent width above 80
Angstroms and line+continuum flux between 2.6e-17 and 5.2e-17 erg/cm^2/sec in
an 80 Angstrom filter) have an observed surface density corresponding to 11000
+- 700 per square degree per unit redshift at z=4.5. Spatial variation in this
surface density is apparent on comparison between counts in 6561 and 6730
Angstrom filters.
Early spectroscopic followup results from the Keck telescope included three
sources meeting our criteria for good Lyman alpha candidates. Of these, one is
confirmed as a z=4.52 source, while another remains consistent with either
z=4.55 or z=0.81. We infer that 30 to 50% of our good candidates are bona fide
Lyman alpha emitters, implying a net density of about 4000 Lyman alpha galaxies
per square degree per unit redshift.Comment: 10 pages, 2 figures (3 .ps files), uses AASTeX 4. Submitted to The
Astrophysical Journal Letter
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