1,409 research outputs found
Monomorphic subtelomeric DNA in the filamentous fungus, Metarhizium anisopliae, contains a RecQ helicase-like gene.
In most filamentous fungi, telomere-associated sequences (TASs) are polymorphic, and the presence of restriction fragment length polymorphisms (RFLPs) may permit the number of chromosome ends to be estimated from the number of telomeric bands obtained by restriction digestion. Here, we describe strains of Metarhizium, Gliocladium and Paecilomyces species in which only one or a few telomeric bands of unequal intensity are detectable by Southern hybridization, indicating that interchromosomal TAS exchange occurs. We also studied an anomalous strain of Metarhizium anisopliae, which produces polymorphic telomeric bands larger than 8 kb upon digestion of genomic DNA with XhoI. In this case, the first XhoI site in from the chromosome end must lie beyond the presumed monomorphic region. Cloned telomeres from this strain comprise 18?26 TTAGGG repeats, followed at the internal end of the telomere tract by five repeats of the telomere-like sequence TAAACGCTGG. An 8.1-kb TAS clone also contains a gene for a RecQ-like helicase, designated TAH1, suggesting that this TAS is analogous to the Y elements in yeast and the subtelomeric helicase ORFs of Ustilago maydis (UTASRecQ) and Magnaporthe grisea (TLH1). The TAS in the anomalous strain of M. anisopliae, however, appears distinct from these in that it is found at most telomeres and its predicted protein product possesses a significantly longer N-terminal region in comparison to the M. grisea and U. maydis helicases. Hybridization analyses showed that TAH1 homologues are present in all other anomalous M. anisopliae strains studied, as well as in some other polymorphic strains, where the recQ-like gene also appears to be telomere-associated.Published online: 2 June 2005
Analytical relationship for the cranking inertia
The wave function of a spheroidal harmonic oscillator without spin-orbit
interaction is expressed in terms of associated Laguerre and Hermite
polynomials. The pairing gap and Fermi energy are found by solving the BCS
system of two equations. Analytical relationships for the matrix elements of
inertia are obtained function of the main quantum numbers and potential
derivative. They may be used to test complex computer codes one should develop
in a realistic approach of the fission dynamics. The results given for the
Pu nucleus are compared with a hydrodynamical model. The importance of
taking into account the correction term due to the variation of the occupation
number is stressed.Comment: 12 pages, 4 figure
Wideband digital phase comparator for high current shunts
A wideband phase comparator for precise measurements of phase difference of
high current shunts has been developed at INRIM. The two-input digital phase
detector is realized with a precision wideband digitizer connected through a
pair of symmetric active guarded transformers to the outputs of the shunts
under comparison. Data are first acquired asynchronously, and then transferred
from on-board memory to host memory. Because of the large amount of data
collected the filtering process and the analysis algorithms are performed
outside the acquisition routine. Most of the systematic errors can be
compensated by a proper inversion procedure.
The system is suitable for comparing shunts in a wide range of currents, from
several hundred of milliampere up to 100 A, and frequencies ranging between 500
Hz and 100 kHz. Expanded uncertainty (k=2) less than 0.05 mrad, for frequency
up to 100 kHz, is obtained in the measurement of the phase difference of a
group of 10 A shunts, provided by some European NMIs, using a digitizer with
sampling frequency up to 1 MHz. An enhanced version of the phase comparator
employs a new digital phase detector with higher sampling frequency and
vertical resolution. This permits to decrease the contribution to the
uncertainty budget of the phase detector of a factor two from 20 kHz to 100
kHz. Theories and experiments show that the phase difference between two high
precision wideband digitizers, coupled as phase detector, depends on multiple
factors derived from both analog and digital imprint of each sampling system.Comment: 20 pages, 9 figure
Spatially Resolved Far-Ultraviolet Spectroscopy of the Nuclear Region of NGC 1068
We carry out high-resolution FUSE spectroscopy of the nuclear region of NGC
1068. The first set of spectra was obtained with a 30" square aperture that
collects all emission from the narrow-line region. The data reveal a strong
broad OVI component of FWHM ~3500 kms-1 and two narrow OVI 1031/1037 components
of ~350 kms-1. The CIII 977 and NIII 991 emission lines in this spectrum can be
fitted with a narrow component of FWHM ~1000 kms-1 and a broad one of ~2500
kms-1. Another set of seven spatially resolved spectra were made using a long
slit of 1.25" X 20", at steps of ~1" along the axis of the emission-line cone.
We find that (1) Major emission lines in the FUSE wavelength range consist of a
broad and a narrow component; (2) There is a gradient in the velocity field for
the narrow OVI component of ~200 kms-1 from ~2" southwest of the nucleus to ~4"
northeast. A similar pattern is also observed with the broad OVI component,
with a gradient of ~3000 kms-1. These are consistent with the HST/STIS findings
and suggest a biconical structure in which the velocity field is mainly radial
outflow; (3) A major portion of the CIII and NIII line flux is produced in the
compact core. They are therefore not effective temperature diagnostics for the
conical region; and (4) The best-fitted UV continuum suggests virtually no
reddening, and the HeII 1085/1640 ratio suggests a consistently low extinction
factor across the cone.Comment: To appear in the Astrophysical Journal. 37 pages with 12 figure
HST Observations of the Serendipitous X-ray Companion to Mrk 273: Cluster at z=0.46?
We have used HST I-band images to identify Mrk 273X, the very unusual
high-redshift X-ray-luminous Seyfert 2 galaxy found by ROSAT in the same
field-of-view as Mrk 273. We have measured the photometric properties of Mrk
273X and have also analyzed the luminosity distribution of the faint galaxy
population seen in the HST image. The luminosity of the galaxy and the
properties of the surrounding environment suggest that Mrk 273X is the
brightest galaxy in a relatively poor cluster at a redshift near 0.46. Its
off-center location in the cluster and the presence of other galaxy groupings
in the HST image may indicate that this is a dynamically young cluster on the
verge of merging with its neighboring clusters. We find that Mrk 273X is a
bright featureless elliptical galaxy with no evidence for a disk. It follows
the de Vaucouleurs (r^{1/4}) surface brightness law very well over a range of 8
magnitudes. Though the surface brightness profile does not appear to be
dominated by the AGN, the galaxy has very blue colors that do appear to be
produced by the AGN. Mrk 273X is most similar to the IC 5063 class of active
galaxies --- a hybrid Sy 2 / powerful radio galaxy.Comment: Accepted for publication in the Astrophysical Journal. 8 pages,
including 4 postscript figures. Uses emulateapj.sty and psfig.sty. Higher
quality version of Figure 1 is available at
http://rings.gsfc.nasa.gov/~borne/fig1-markgals.gi
Time-odd mean fields in the rotating frame: microscopic nature of nuclear magnetism
The microscopic role of nuclear magnetism in rotating frame is investigated
for the first time in the framework of the cranked relativistic mean field
theory. It is shown that nuclear magnetism modifies the expectation values of
single-particle spin, orbital and total angular momenta along the rotational
axis effectively creating additional angular momentum. This effect leads to the
increase of kinematic and dynamic moments of inertia at given rotational
frequency and has an impact on effective alignments.Comment: 16 pages, 4 figures, submitted to Physical Review
Generalized Involution Models for Wreath Products
We prove that if a finite group has a generalized involution model, as
defined by Bump and Ginzburg, then the wreath product also has a
generalized involution model. This extends the work of Baddeley concerning
involution models for wreath products. As an application, we construct a
Gelfand model for wreath products of the form with abelian, and
give an alternate proof of a recent result due to Adin, Postnikov, and Roichman
describing a particularly elegant Gelfand model for the wreath product \ZZ_r
\wr S_n. We conclude by discussing some notable properties of this
representation and its decomposition into irreducible constituents, proving a
conjecture of Adin, Roichman, and Postnikov's.Comment: 29 page
Detection of Trichomonas vaginalis Using the Polymerase Chain Reaction in Pregnant and Non-Pregnant Women
Objective: Trichomonas vaginalis vaginal infections are often both asymptomatic and difficult to
detect by current methods. We evaluated the ability of a newly developed polymerase chain reaction (PCR) assay to
identify T. vaginalis in vaginal samples from pregnant and non-pregnant women
Investigating on the nuclear obscuration in two types of Seyfert 2 galaxies
We build a large sample of Seyfert 2 galaxies (Sy2s) with both optical
spectropolarimetric and X-ray data available, in which 29 Sy2s with the
detection of polarized broad emission line (PBL) and 25 without. We find that
for luminous Sy2s with L_[OIII] > 10^41 erg/s, sources with PBL have smaller
X-ray absorption column density comparing with those without PBL (at 92.3%
confidence level): most of the Sy2s with N_H<10^23.8 cm^-2 show PBL (86%, 12
out 14), while the fraction is much smaller for sources with heavier
obscuration (54%, 15 out 28). The confidence level of the difference in
absorption bounces up to 99.1% while using the "T" ratio (F_2-10keV/F_[O III])
as an indicator. We rule out observation or selection bias as the origin for
the difference. Our results, for the first time with high statistical
confidence, show that, in additional to the nuclei activity, the nuclear
obscuration also plays an important role in the visibility of PBL in Sy2s.
These results can be interpreted in the framework of the unified model. We can
reach these results in the unified model if: a) the absorption column density
is higher at large inclinations and b) the scattering region is obscured at
large inclinations.Comment: 28 pages, including 7 figures and 3 tables, ApJ accepte
A Radio Study of the Seyfert Galaxy IC 5063: Evidence for Fast Gas Outflow
New radio continuum (8 GHz and 1.4 GHz) and HI 21 cm line observations of the
Seyfert 2 galaxy IC 5063 (PKS 2048-572) were obtained with the Australia
Telescope Compact Array (ATCA). The 8 GHz image reveals a linear triple
structure (~4'', 1.5 kpc) oriented perpendicular to the optical polarization
position angle. It is aligned with the inner dust lane and shows strong
morphological association with the narrow emission line region (NLR). At 21 cm,
very broad (~700 km/s) HI absorption is observed against the strong continuum
source. This absorption is almost entirely blueshifted, indicating a fast net
outflow, but a faint and narrow redshifted component is also present. In IC
5063 we see clear evidence for strong shocks resulting from the radio
plasma-ISM interaction in the central few kpc. However, the energy flux in the
radio plasma is an order of magnitude smaller than the energy emitted in
emission lines. Thus, shocks are unlikely to account solely for the global
ionization of the emission line region, particularly at large distances.
The HI emission outlines a warped disk associated with the system of dust
lanes some ~2' (~38 kpc) in radius. The lack of kinematically disturbed gas
outside the central few kpc, coupled with the disk warp and close morphological
connection of the inner dust lanes and the large-scale ionized gas, support the
idea that the gas at large radii is photoionized by the central region, while
shadowing effects are important in defining its X-shaped morphology. The
kinematics of the ionized and of the neutral gas suggests the existence of a
dark halo.Comment: 18 pages, 8 Postscript figures, 3 jpeg figures, Postscript preprint
is available from http://jhufos.pha.jhu.edu/~zlatan/papers.htm
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