628 research outputs found
Rebuild to Preserve: renewal of the historical buildings along the alleyways in Kyoto (Japan)
Ponència presentada a: Session 9: Forma urbana y relaciones entre historia y proyecto: el medio ambiente como patrimonio / Urban form and relationships between design and history: environmental heritage, arquitecture and plannin
Public participation in planning and preservation of alleyways in Japan
Ponència presentada a: Session 2: Post-ocupación / Post-occupancy: buildings and citie
Equilibrium Properties of Mouse-Torpedo Acetylcholine Receptor Hybrids Expressed in Xenopus Oocytes
This study used messenger RNA encoding each subunit (α, β, γ
and δ) of the nicotinic acetylcholine (ACh) receptor from mouse BC3H-1 cells and from Torpedo electric organ. The mRNA was synthesized in vitro by transcription with SP6 polymerase from cDNA clones. All 16 possible combinations that include one mRNA for each of α, β, γ and δ were injected into oocytes. After allowing 2-8 d for translation and assembly, we assayed each oocyte for (a) receptor assembly, measured by the binding of [^125]α-bungarotoxin to the oocyte surface, and (b) ACh-induced conductance, measured under voltage clamp at various membrane potentials. All combinations yielded detectable
assembly (30-fold range among different combinations) and ACh-induced
conductances (>1,000-fold range at 1 µM). On double-logarithmic coordinates, the dose-response relations all had a slope near 2 for low concentrations of ACh. Data were corrected for variations in efficiency of translation among identically injected oocytes by expressing ACh-induced conductance per femtomole
of α-bungarotoxin-binding sites. Five combinations were tested for d-tubocurarine
inhibition by the dose-ratio method; the apparent dissociation
constant ranged from 0.08 to 0.27 µM. Matched responses and geometric
means are used for describing the effects of changing a particular subunit
(mouse vs. Torpedo) while maintaining the identity of the other subunits. A
dramatic subunit-specific effect is that of the β subunit on voltage sensitivity of
the response: g_ACh(-90 mV)/g_Ach(+30 mV) is always at least 1, but this ratio
increases by an average of 3.5-fold if β_M replaces β_T. Also, combinations
including γ_T or δ_M usually produce greater receptor assembly than combinations
including the homologous subunit from the other species. Finally, E_ACh is
defined as the concentration of ACh inducing 1 µS/fmol at -60 mV; E_ACh is
consistently lower for α_m. We conclude that receptor assembly, voltage sensitivity,
and E_ACh are governed by different properties
Variation of Inner Radius of Dust Torus in NGC4151
The long-term optical and near infrared monitoring observations for a type 1
act ive galactic nucleus NGC 4151 were carried out for six years from 2001 to
2006 b y using the MAGNUM telescope, and delayed response of flux variations in
the band to those in the band was clearly
detected. Based on cross correlation analysis, we precisely measured a lag time
for eight separate periods, and we found that is not
constant changing be tween 30 and 70 days during the monitoring period. Since
is the ligh t travel time from the central energy source out to the
surrounding dust torus, this is the first convincing evidence that the inner
radius of dust torus did ch ange in an individual AGN. In order to relate such
a change of with a change of AGN luminosity , we presented a
method of taking an average of th e observed -band fluxes that corresponds
to the measured value of , and we found that the time-changing track
of NGC 4151 in the versus diagram during the monitoring period
deviates from the relation of expected from dust
reverberation. This result, combined with t he elapsed time from period to
period for which was measured, indicat es that the timescale of dust
formation is about one year, which should be taken into account as a new
constraint in future studies of dust evolution in AGNs.Comment: 5 pages, 3 figures, To appear in the ApJ Lette
Protostellar Collapse with Various Metallicities
The thermal and chemical evolution of gravitationally collapsing protostellar
clouds is investigated, focusing attention on their dependence on metallicity.
Calculations are carried out for a range of metallicities spanning the local
interstellar value to zero. During the time when clouds are transparent to
continuous radiation, the temperatures are higher for those with lower
metallicity, reflecting lower radiative ability. However, once the clouds
become opaque, in the course of the adiabatic contraction of the transient
cores, their evolutionary trajectories in the density-temperature plane
converge to a unique curve that is determined by only physical constants. The
trajectories coincide with each other thereafter. Consequently, the size of the
stellar core at the formation is the same regardless of the gas composition of
the parent cloud.Comment: 30 pages. The Astrophysical Journal, 533, in pres
Long-Term Optical Continuum Color Variability of Nearby Active Galactic Nuclei
We examine whether the spectral energy distribution of optical continuum
emission of active galactic nuclei (AGNs) changes during flux variation, based
on accurate and frequent monitoring observations of 11 nearby Seyfert galaxies
and QSOs carried out in the B, V, and I bands for seven years by the MAGNUM
telescope. The multi-epoch flux data in any two different bands obtained on the
same night show a very tight linear flux to flux relationship for all target
AGNs. The flux of the host galaxy within the photometric aperture is carefully
estimated by surface brightness fitting to available high-resolution HST images
and MAGNUM images. The flux of narrow emission lines in the photometric bands
is also estimated from available spectroscopic data. We find that the
non-variable component of the host galaxy plus narrow emission lines for all
target AGNs is located on the fainter extension of the linear regression line
of multi-epoch flux data in the flux to flux diagram. This result strongly
indicates that the spectral shape of AGN continuum emission in the optical
region does not systematically change during flux variation. The trend of
spectral hardening that optical continuum emission becomes bluer as it becomes
brighter, which has been reported by many studies, is therefore interpreted as
the domination of the variable component of the nearly constant spectral shape
of an AGN as it brightens over the non-variable component of the host galaxy
plus narrow lines, which is usually redder than AGN continuum emission.Comment: 47 pages, 29 figures, AASTeX, Accepted for publication in Ap
Reverberation measurements of the inner radius of the dust torus in 17 seyfert galaxies
We present the results of a dust reverberation survey for 17 nearby Seyfert 1 galaxies, which provides the largest homogeneous data collection for the radius of the innermost dust torus. A delayed response of the K-band light curve after the V-band ligh
The Lick AGN Monitoring Project: Broad-Line Region Radii and Black Hole Masses from Reverberation Mapping of Hbeta
We have recently completed a 64-night spectroscopic monitoring campaign at
the Lick Observatory 3-m Shane telescope with the aim of measuring the masses
of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected
masses in the range ~10^6-10^7 M_sun and also the well-studied nearby active
galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including
NGC 5548) showed optical variability of sufficient strength during the
monitoring campaign to allow for a time lag to be measured between the
continuum fluctuations and the response to these fluctuations in the broad
Hbeta emission. We present here the light curves for the objects in this sample
and the subsequent Hbeta time lags for the nine objects where these
measurements were possible. The Hbeta lag time is directly related to the size
of the broad-line region, and by combining the lag time with the measured width
of the Hbeta emission line in the variable part of the spectrum, we determine
the virial mass of the central supermassive black hole in these nine AGNs. The
absolute calibration of the black hole masses is based on the normalization
derived by Onken et al. We also examine the time lag response as a function of
velocity across the Hbeta line profile for six of the AGNs. The analysis of
four leads to ambiguous results with relatively flat time lags as a function of
velocity. However, SBS 1116+583A exhibits a symmetric time lag response around
the line center reminiscent of simple models for circularly orbiting broad-line
region (BLR) clouds, and Arp 151 shows an asymmetric profile that is most
easily explained by a simple gravitational infall model. Further investigation
will be necessary to fully understand the constraints placed on physical models
of the BLR by the velocity-resolved response in these objects.Comment: 24 pages, 16 figures and 13 tables, submitted to Ap
The Lick AGN Monitoring Project: Photometric Light Curves and Optical Variability Characteristics
The Lick AGN Monitoring Project targeted 13 nearby Seyfert 1 galaxies with
the intent of measuring the masses of their central black holes using
reverberation mapping. The sample includes 12 galaxies selected to have black
holes with masses roughly in the range 10^6-10^7 solar masses, as well as the
well-studied AGN NGC 5548. In conjunction with a spectroscopic monitoring
campaign, we obtained broad-band B and V images on most nights from 2008
February through 2008 May. The imaging observations were carried out by four
telescopes: the 0.76-m Katzman Automatic Imaging Telescope (KAIT), the 2-m
Multicolor Active Galactic Nuclei Monitoring (MAGNUM) telescope, the Palomar
60-in (1.5-m) telescope, and the 0.80-m Tenagra II telescope. Having
well-sampled light curves over the course of a few months is useful for
obtaining the broad-line reverberation lag and black hole mass, and also allows
us to examine the characteristics of the continuum variability. In this paper,
we discuss the observational methods and the photometric measurements, and
present the AGN continuum light curves. We measure various variability
characteristics of each of the light curves. We do not detect any evidence for
a time lag between the B- and V-band variations, and we do not find significant
color variations for the AGNs in our sample.Comment: 16 pages, 20 figures, 8 tables, accepted for publication in ApJ
The Possibility of the Curriculum Designs implemented by the Social Studies Teachers : A Case Study on the Development and Application of the History Resource Book
The purposes of this paper are to describe the curriculum designs implemented by the four Social Studies teachers in the same school but from the different background, and to explain the reasons why they showed the various designs, even though they are requested to apply the common history resource book into the regular classes.
The present results suggested that the ideas and aims concerning the subject which each Social Studies teacher conceived had much influences on the differentiation of their practices, but their experiences of the professional development on the curriculum and instruction, the orientation of the school management, and the leadership demonstrated by the principal had more influences on the assimilation of their attitude toward the class improvement, particularly in the case of sampled teachers and school
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