4,182 research outputs found
A Microscopic Mechanism for Muscle's Motion
The SIRM (Stochastic Inclined Rods Model) proposed by H. Matsuura and M.
Nakano can explain the muscle's motion perfectly, but the intermolecular
potential between myosin head and G-actin is too simple and only repulsive
potential is considered. In this paper we study the SIRM with different complex
potential and discuss the effect of the spring on the system. The calculation
results show that the spring, the effective radius of the G-actin and the
intermolecular potential play key roles in the motion. The sliding speed is
about calculated from the model which well agrees with
the experimental data.Comment: 9 pages, 6 figure
Early Dust Formation and a Massive Progenitor for SN 2011ja?
SN 2011ja was a bright (I = -18.3) Type II supernova occurring in the nearby
edge on spiral galaxy NGC 4945. Flat-topped and multi-peaked H-alpha and H-beta
spectral emission lines appear between 64 - 84 days post-explosion, indicating
interaction with a disc-like circumstellar medium inclined 30-45 degrees from
edge-on. After day 84 an increase in the H- and K-band flux along with heavy
attenuation of the red wing of the emission lines are strong indications of
early dust formation, likely located in the cool dense shell created between
the forward shock of the SN ejecta and the reverse shock created as the ejecta
plows into the existing CSM. Radiative transfer modeling reveals both ~1.5 x
10^-4 Msun of pre-existing dust located ~ 10^16.7 cm away and ~ 5 x 10^-5 Msun
of newly formed dust. Spectral observations after 1.5 years reveal the
possibility that the fading SN is located within a young (3-6 Myr) massive
stellar cluster, which when combined with tentative 56Ni mass estimates of 0.2
Msun may indicate a massive (> 25 Msun) progenitor for SN 2011ja.Comment: 13 pages, 8 figures, submitted to MNRAS awaiting final referee repor
Excited D-branes and Supergravity Solutions
We investigate the general solution with the symmetry ISO(1,p)xSO(9-p) of
Type II supergravity (the three-parameter solution) from the viewpoint of the
superstring theory. We find that one of the three parameters (c_1) is closely
related to the ``dilaton charge'' and the appearance of the dilaton charge is a
consequence of deformations of the boundary condition from that of the boundary
state for BPS D-branes. We give three examples of the deformed D-branes by
considering the tachyon condensation from systems of D-\bar{D}p-branes,
unstable D9-branes and unstable D-instantons to the BPS saturated Dp-branes,
respectively. We argue that the deformed systems are generally regarded as
tachyonic and/or massive excitations of the open strings on Dp-\bar{D}p-brane
systems.Comment: 29 pages, 6 figures, LaTeX2e, typos corrected, references adde
A decade of ejecta dust formation in the Type IIn SN 2005ip
In order to understand the contribution of core-collapse supernovae to the
dust budget of the early universe, it is important to understand not only the
mass of dust that can form in core-collapse supernovae but also the location
and rate of dust formation. SN 2005ip is of particular interest since dust has
been inferred to have formed in both the ejecta and the post-shock region
behind the radiative reverse shock. We have collated eight optical archival
spectra that span the lifetime of SN 2005ip and we additionally present a new
X-shooter optical-near-IR spectrum of SN 2005ip at 4075d post-discovery. Using
the Monte Carlo line transfer code DAMOCLES, we have modelled the blueshifted
broad and intermediate width H, H and He I lines from 48d to
4075d post-discovery using an ejecta dust model. We find that dust in the
ejecta can account for the asymmetries observed in the broad and intermediate
width H, H and He I line profiles at all epochs and that it is
not necessary to invoke post-shock dust formation to explain the blueshifting
observed in the intermediate width post-shock lines. Using a Bayesian approach,
we have determined the evolution of the ejecta dust mass in SN 2005ip over 10
years presuming an ejecta dust model, with an increasing dust mass from
~10 M at 48d to a current dust mass of 0.1 M.Comment: Accepted by MNRAS, 17 pages, 11 figures. Author accepted manuscript.
Accepted on 04/03/19. Deposited on 07/03/1
Carbon-rich dust production in metal-poor galaxies in the Local Group
We have observed a sample of 19 carbon stars in the Sculptor, Carina, Fornax,
and Leo I dwarf spheroidal galaxies with the Infrared Spectrograph on the
Spitzer Space Telescope. The spectra show significant quantities of dust around
the carbon stars in Sculptor, Fornax, and Leo I, but little in Carina. Previous
comparisons of carbon stars with similar pulsation properties in the Galaxy and
the Magellanic Clouds revealed no evidence that metallicity affected the
production of dust by carbon stars. However, the more metal-poor stars in the
current sample appear to be generating less dust. These data extend two known
trends to lower metallicities. In more metal-poor samples, the SiC dust
emission weakens, while the acetylene absorption strengthens. The bolometric
magnitudes and infrared spectral properties of the carbon stars in Fornax are
consistent with metallicities more similar to carbon stars in the Magellanic
Clouds than in the other dwarf spheroidals in our sample. A study of the carbon
budget in these stars reinforces previous considerations that the dredge-up of
sufficient quantities of carbon from the stellar cores may trigger the final
superwind phase, ending a star's lifetime on the asymptotic giant branch.Comment: ApJ, in press, 21 pages, 12 figures. Replaced Fig 12, corrected two
reference
Usage and Attitudes of Physicians in Japan Concerning Traditional Japanese Medicine (Kampo Medicine): A Descriptive Evaluation of a Representative Questionnaire-Based Survey
Kampo medicine has been the primary medical model in Japan until the mid 1800s, regained a prominent role in today's Japanese medical system. Today, 148 herbal Kampo formulas can be prescribed under the national health insurance system, allowing physicians to integrate Kampo in their daily practice. This article aims to provide information about the extent to which Kampo is now used in clinics throughout Japan and about physician's current attitudes toward Kampo. We used the results of a 2008 survey that was administered to physicians throughout Japan (n = 684). The data showed that 83.5% of physicians currently use Kampo in the clinic, although the distribution of physicians who use Kampo differ widely depending on the specialty and provided a breakdown of Kampo usage by specialty. It will be interesting to see how each specialty incorporates Kampo into its respective field as Kampo continues to play a pertinent role in Japanese medical system
156 THE ROLE OF THE VOLUME-SENSITIVE CL- CURRENT IN THE PROCESS OF REGULATORY VOLUME DECREASE (RVD) IN FRESHLY ISOLATED RABBIT ARTICULAR CHONDROCYTES
Stand-alone water treatment: performance of electrospun nanofibers
The aim of this study was to evaluate the use of nanofiber microfiltration membranes, spun by an innovative electrospinning technique, in water filtration applications. This study bridges between developments in electrospinning techniques for the production of flat sheet membranes and the application of these membranes in water filtration. The functionalized or non-functionalized for the removal of pathogens was investigated, in term of chemical oxygen demand, total suspend solid and ammonium in the waste water. Physical properties such as clean water permeability (CWP) and strength were also examined. The results showed a very good removal of TSS (range 94.83-97.34%), COD (89.32-95.27%) and NH3-N (64.48-72.87%). These test showed that the electrospun membranes can be used for water filtration applications
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