2,305 research outputs found
Re-evaluating the role of natural killer cells in innate resistance to herpes simplex virus type 1
BACKGROUND: Interferon-Îł acts to multiply the potency with which innate interferons (α/ÎČ) suppress herpes simplex virus type 1 (HSV-1) replication. Recent evidence suggests that this interaction is functionally relevant in host defense against HSV-1. However, it is not clear which WBCs of the innate immune system, if any, limit HSV-1 spread in an IFN-Îł dependent manner. The current study was initiated to determine if natural killer (NK) cells provide innate resistance to HSV-1 infection, and if so to determine if this resistance is IFN-Îł-dependent. RESULTS: Lymphocyte-deficient scid or rag2(-/- )mice were used to test four predictions of the central hypothesis, and thus determine if innate resistance to HSV-1 is dependent on 1. NK cell cytotoxicity, 2. NK cells, 3. WBCs, or 4. the IFN-activated transcription factor, Stat 1. Loss of NK cell cytotoxic function or depletion of NK cells had no effect on the progression of HSV-1 infection in scid mice. In contrast, viral spread and pathogenesis developed much more rapidly in scid mice depleted of WBCs. Likewise, loss of Stat 1 function profoundly impaired the innate resistance of rag2(-/- )mice to HSV-1. CONCLUSION: Lymphocyte-deficient mice possess a very tangible innate resistance to HSV-1 infection, but this resistance is not dependent upon NK cells
The Magnitude-Size Relation of Galaxies out to z ~ 1
As part of the Deep Extragalactic Evolutionary Probe (DEEP) survey, a sample
of 190 field galaxies (I_{814} <= 23.5) in the ``Groth Survey Strip'' has been
used to analyze the magnitude-size relation over the range 0.1 < z < 1.1. The
survey is statistically complete to this magnitude limit. All galaxies have
photometric structural parameters, including bulge fractions (B/T), from Hubble
Space Telescope images, and spectroscopic redshifts from the Keck Telescope.
The analysis includes a determination of the survey selection function in the
magnitude-size plane as a function of redshift, which mainly drops faint
galaxies at large distances. Our results suggest that selection effects play a
very important role. A first analysis treats disk-dominated galaxies with B/T <
0.5. If selection effects are ignored, the mean disk surface brightness
(averaged over all galaxies) increases by ~1.3 mag from z = 0.1 to 0.9.
However, most of this change is plausibly due to comparing low luminosity
galaxies in nearby redshift bins to high luminosity galaxies in distant bins.
If this effect is allowed for, no discernible evolution remains in the disk
surface brightness of bright (M_B < -19) disk-dominated galaxies. A second
analysis treats all galaxies by substituting half-light radius for disk scale
length, with similar conclusions. Indeed, at all redshifts, the bulk of
galaxies is consistent with the magnitude-size envelope of local galaxies,
i.e., with little or no evolution in surface brightness. In the two highest
redshift bins (z > 0.7), a handful of luminous, high surface brightness
galaxies appears that occupies a region of the magnitude-size plane rarely
populated by local galaxies. Their wide range of colors and bulge fractions
points to a variety of possible origins.Comment: 19 pages, 12 figures. Accepted for publication in the Astrophysical
Journa
Hydrodynamical evolution near the QCD critical end point
Hydrodynamical calculations have been successful in describing global
observables in ultrarelativistic heavy ion collisions, which aim to observe the
production of the quark-gluon plasma. On the other hand, recently, a lot of
evidence that there exists a critical end point (CEP) in the QCD phase diagram
has been accumulating. Nevertheless, so far, no equation of state with the CEP
has been employed in hydrodynamical calculations. In this paper, we construct
the equation of state with the CEP on the basis of the universality hypothesis
and show that the CEP acts as an attractor of isentropic trajectories. We also
consider the time evolution in the case with the CEP and discuss how the CEP
affects the final state observables, such as the correlation length,
fluctuation, chemical freezeout, kinetic freezeout, and so on. Finally, we
argue that the anomalously low kinetic freezeout temperature at the BNL
Relativistic Heavy Ion Collider suggests the possibility of the existence of
the CEP.Comment: 13 pages, 12 figures, accepted for publication in Physical Review
Periodically kicked turbulence
Periodically kicked turbulence is theoretically analyzed within a mean field
theory. For large enough kicking strength A and kicking frequency f the
Reynolds number grows exponentially and then runs into some saturation. The
saturation level can be calculated analytically; different regimes can be
observed. For large enough Re we find the saturation level to be proportional
to A*f, but intermittency can modify this scaling law. We suggest an
experimental realization of periodically kicked turbulence to study the
different regimes we theoretically predict and thus to better understand the
effect of forcing on fully developed turbulence.Comment: 4 pages, 3 figures. Phys. Rev. E., in pres
UBVI Surface Photometry of the Spiral Galaxy NGC 300 in the Sculptor Group
We present UBVI surface photometry for 20.'5 X 20.'5 area of a late-type
spiral galaxy NGC 300. In order to understand the morphological properties and
luminosity distribution characteristics of NGC 300, we have derived isophotal
maps, surface brightness profiles, ellipticity profiles, position angle
profiles, and color profiles. By merging the I-band data of our surface
brightness measurements with those of Boeker et al. (2002) based on Hubble
Space Telescope observations, we have made combined I-band surface brightness
profiles for the region of 0."02 < r < 500" and decomposed the profiles into
three components: a nucleus, a bulge, and an exponential disk.Comment: 16 pages(cjaa209.sty), Accepted by the Chinese J. Astron. Astrophys.,
Fig 2 and 8 are degraded to reduce spac
Stratospheric ozone trends and variability as seen by SCIAMACHY from 2002 to 2012
Vertical profiles of the rate of linear change (trend) in the altitude range
15â50 km are determined from decadal O<sub>3</sub> time series obtained from
SCIAMACHY<sup>1</sup>/ENVISAT<sup>2</sup>
measurements in limb-viewing geometry. The trends are calculated by using a
multivariate linear regression. Seasonal variations, the quasi-biennial
oscillation, signatures of the solar cycle and the El NiñoâSouthern
Oscillation are accounted for in the regression. The time range of trend
calculation is August 2002âApril 2012. A focus for analysis are the zonal
bands of 20° Nâ20° S (tropics), 60â50° N, and
50â60° S (midlatitudes). In the tropics, positive trends of up to
5% per decade between 20 and 30 km and negative trends of up to
10% per decade between 30 and 38 km are identified. Positive O<sub>3</sub>
trends of around 5% per decade are found in the upper stratosphere in
the tropics and at midlatitudes. Comparisons between SCIAMACHY and EOS
MLS<sup>3</sup> show
reasonable agreement both in the tropics and at midlatitudes for most
altitudes. In the tropics, measurements from OSIRIS<sup>4</sup>/Odin and SHADOZ<sup>5</sup> are also analysed. These yield rates of
linear change of O<sub>3</sub> similar to those from SCIAMACHY. However, the
trends from SCIAMACHY near 34 km in the tropics are larger than MLS and
OSIRIS by a factor of around two.
<br><br>
<br><br>
<sup>1</sup> SCanning Imaging Absorption spectroMeter for Atmospheric
CHartographY
<sup>2</sup> European environmental research satellite
<sup>3</sup> Earth Observing System (EOS) Microwave Limb Sounder (MLS)
<sup>4</sup> Optical Spectrograph and InfraRed Imager System
<sup>5</sup> Southern Hemisphere ADditional OZonesonde
SuperMassive Black Holes in Bulges
We present spatially extended gas kinematics at parsec-scale resolution for
the nuclear regions of four nearby disk galaxies, and model them as rotation of
a gas disk in the joint potential of the stellar bulge and a putative central
black hole. The targets were selected from a larger set of long-slit spectra
obtained with the Hubble Space Telescope as part of the Survey of Nearby Nuclei
with STIS (SUNNS). They represents the 4 galaxies (of 24) that display
symmetric gas velocity curves consistent with a rotating disk. We derive the
stellar mass distribution from the STIS acquisition images adopting the stellar
mass-to-light ratio normalized so as to match ground-based velocity dispersion
measurements over a large aperture. Subsequently, we constrain the mass of a
putative black hole by matching the gas rotation curve, following two distinct
approaches. In the most general case we explore all the possible disk
orientations, alternatively we constrain the gas disk orientation from the
dust-lane morphology at similar radii. In the latter case the kinematic data
indicate the presence of a central black hole for three of the four objects,
with masses of 10^7 - 10^8 solar masses, representing up to 0.025 % of the host
bulge mass. For one object (NGC2787) the kinematic data alone provide clear
evidence for the presence of a central black hole even without external
constraints on the disk orientation. These results illustrate directly the need
to determine black-hole masses by differing methods for a large number of
objects, demonstrate that the variance in black hole/bulge mass is much larger
than previously claimed, and reinforce the recent finding that the black-hole
mass is tightly correlated with the bulge stellar velocity dispersion.Comment: 26 pages, 11 Postscript figures, accepted for publication on Ap
Einstellungen und Selbstwirksamkeit von Lehrerinnen und Lehrern zur schulischen Inklusion in Deutschland - eine Analyse mit Daten des Nationalen Bildungspanels Deutschlands (NEPS)
In Deutschland wird der gemeinsame Unterricht von SchĂŒlerinnen und SchĂŒlern mit und ohne sonderpĂ€dagogischem Förderbedarf im Schulsystem stark ausgebaut. Als eine wichtige Voraussetzung fĂŒr eine gelungene Umsetzung des gemeinsamen Unterrichts wird in der Forschung die Einstellungen der beteiligten Lehrerinnen und Lehrer zur Inklusion gesehen. Der vorliegende Bei- trag berichtet ĂŒber die Selbstwirksamkeit und die allgemeine Einstellung zur Inklusion bei 130 KlassenlehrkrĂ€ften in der der 2. Welle der Startkohorte 3 (6. Jahrgangsstufe) des Nationalen Bildungspanels (NEPS). Insgesamt haben die RegelschullehrkrĂ€fte eine positive Einstellung gegenĂŒber der Inklusion, jedoch ist die Selbstwirksamkeit in Bezug auf Inklusion eher gering ausgeprĂ€gt. Die befragten KlassenlehrkrĂ€fte in Förderschulen trauen sich dagegen die Umsetzung des gemeinsamen Unterrichts eher zu. GegenĂŒber der Inklusion haben sie jedoch Bedenken und halten die Förderschule fĂŒr den optimaleren Förderort fĂŒr SchĂŒlerinnen und SchĂŒler mit sonderpĂ€dagogischem Förderbedarf
Phase ordering and shape deformation of two-phase membranes
Within a coupled-field Ginzburg-Landau model we study analytically phase
separation and accompanying shape deformation on a two-phase elastic membrane
in simple geometries such as cylinders, spheres and tori. Using an exact
periodic domain wall solution we solve for the shape and phase ordering field,
and estimate the degree of deformation of the membrane. The results are
pertinent to a preferential phase separation in regions of differing curvature
on a variety of vesicles.Comment: 4 pages, submitted to PR
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