2,273 research outputs found
Isomonodromic deformations of connections with singularities of parahoric formal type
In previous work, the authors have developed a geometric theory of
fundamental strata to study connections on the projective line with irregular
singularities of parahoric formal type. In this paper, the moduli space of
connections that contain regular fundamental strata with fixed combinatorics at
each singular point is constructed as a smooth Poisson reduction. The authors
then explicitly compute the isomonodromy equations as an integrable system.
This result generalizes work of Jimbo, Miwa, and Ueno to connections whose
singularities have parahoric formal type.Comment: 32 pages. One of the main theorems (Theorem 5.1) has been
significantly strengthened. It now states that the isomonodromy equations
give rise to an integrable system on the moduli space of framed connections
with fixed combinatorics instead of only on a principal GL_n bundle over this
space. Sections 5 and 6 have been substantially rewritte
The Archean crust in the Wawa-Chapleau-Timmins region. A field guidebook prepared for the 1983 Archean Geochemistry-Early Crustal Genesis Field Conference
This guidebook describes the characteristics and interrelationships of Archean greenstone-granite and high-grade gneiss terrains of the Superior Province. A 300-km long west to east transect between Wawa and Timmins, Ontario will be used to illustrate regional-scale relationships. The major geological features of the Superior Province are described
Coupled surface plasmon-polariton mediated photoluminescence from a top-emitting organic light-emitting structure
Copyright © 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 85 (2004) and may be found at http://link.aip.org/link/?APPLAB/85/182/1We report strong photoluminescence from a top-emitting organic light-emitting structure where emission takes place through a thin (55 nm) silver film. We show that this emission is mediated via coupled surface plasmon-polariton modes. Our results show that the addition of a dielectric grating to otherwise planar structures, such as surface-emitting organic light-emitting diodes, may offer a way to increase the external efficiency of top-emitting organic light-emitting diodes
Evolving mass spectra of the oxidized component of organic aerosol: results from aerosol mass spectrometer analyses of aged diesel emissions
International audienceThe species and chemistry responsible for secondary organic aerosol (SOA) formation remain highly uncertain. Laboratory studies of the oxidation of individual, high-flux SOA precursors do not lead to particles with mass spectra (MS) matching those of ambient aged organic material. Additionally, the complexity of real organic particles challenges efforts to identify their chemical origins. We have previously hypothesized that SOA can form from the atmospheric oxidation of a large suite of precursors with varying vapor pressures. Here, we support this hypothesis by using an aerosol mass spectrometer to track the chemical evolution of diesel exhaust as it is photochemically oxidized in an environmental chamber. With explicit knowledge of the condensed-phase MS of the primary emissions from our engine, we are able to decompose each recorded MS into contributing primary and secondary spectra throughout the experiment. We find that the SOA becomes increasingly oxidized as a function of time, quickly approaching a final MS that closely resembles that of ambient aged organic particulate matter. This observation is consistent with our hypothesis of an evolving suite of SOA precursors. Low vapor pressure, semi-volatile organic emissions can form condensable products with even a single generation of oxidation, resulting in an early-arising, relatively less-oxidized SOA. Continued gas-phase oxidation can form highly oxidized SOA in surprisingly young air masses via reaction mechanisms that can add multiple oxygen atoms per generation and result in products with sustained or increased reactivity toward OH
Increased levels of type VIII collagen in human brain tumours compared to normal brain tissue and non-neoplastic cerebral disorders.
The expression of type VIII collagen was examined in the normal and diseased human brain. Focal immunoreactivity was seen in histologically abnormal vessels of all four angiomas and 40 of 52 brain tumours (gliomas, meningiomas and schwannomas). An extended staining pattern, as well as a punctate distribution, was frequently observed in affected vessels. Staining was not apparent in nine normal brains and in 15 pathologic brains showing various cerebrovascular abnormalities, including Alzheimer's, Leigh's and Wernicke's diseases. Immunoblotting of glioblastomas revealed two bands at 56 kD and 67 kD which were also present at low levels in normal frontal cortex. The extracellular distribution of type VIII collagen was different from that of the other collagen types which have been described in brain and resembles patterns of expression described for certain tissues during mammalian embryogenesis (Kapoor et al., 1988). Our results provide additional evidence for the participation of type VIII collagen in some types of angiogenesis
Recent Legal Literature
Noyes: American Railroad Rates; Meyer: Railway Legislation in the United States; Diccy: Lectures on the Relation between Law and Public Opinion in England During the Nineteenth Century; Page: Law of Contracts; Camp: The Encyclopaedia of Evidence; Clement: Fire Insurance as a Void Conttract and as Affected by Construction and Waiver of Estoppel, including miscellaneous provisions and an analysis and comparison of the various standard forms, all reduced to rules with the relevant statutory provisions of all the states. Volume II.; Woodruff: A Selection of Cases on Domestic Relations and the Law of Persons; Kinkead: Jurisprudence Law and Ethics; Schouler: Law of the Domestic Relations Embracing Husband and Wife, Parent and Child, Fuardian and Ward, Infancy and Master and Servant; Hoyt (ed.): Report of the Colorado Bar Association. Volume 8
Molecular Gas in Candidate Double-Barred Galaxies II. Cooler, Less Dense Gas Associated with Stronger Central Concentrations
We have performed a multi-transition CO study of the centers of seven
double-barred galaxies that exhibit a variety of molecular gas morphologies to
determine if the molecular gas properties are correlated with the nuclear
morphology and star forming activity. Near infrared galaxy surveys have
revealed the existence of nuclear stellar bars in a large number of barred or
lenticular galaxies. High resolution CO maps of these galaxies exhibit a wide
range of morphologies. Recent simulations of double-barred galaxies suggest
that variations in the gas properties may allow it to respond differently to
similar gravitational potentials. We find that the 12CO J=3-2/J=2-1 line ratio
is lower in galaxies with centrally concentrated gas distributions and higher
in galaxies with CO emission dispersed around the galactic center in rings and
peaks. The 13CO/12CO J=2-1 line ratios are similar for all galaxies, which
indicates that the J=3-2/J=2-1 line ratio is tracing variations in gas
temperature and density, rather than variations in optical depth. There is
evidence that the galaxies which contain more centralized CO distributions are
comprised of molecular gas that is cooler and less dense. Observations suggest
that the star formation rates are higher in the galaxies containing the warmer,
denser, less centrally concentrated gas. It is possible that either the bar
dynamics are responsible for the variety of gas distributions and densities
(and hence the star formation rates) or that the star formation alone is
responsible for modifying the gas properties.Comment: 27 pages + 6 figures; to appear in the April 20, 2003 issue of Ap
Trauma Exposure and Transdiagnostic Distress: Examining Shared and PTSD-Specific Associations
Dimensional models of psychopathology suggest that the causes and consequences of psychopathology are attributable to a combination of syndrome specific and transdiagnostic features. There is considerable evidence that trauma exposure confers risk for a wide range of psychiatric conditions, yet no previous work has specifically examined the higher-order effects of trauma exposure within a structural model. We examined transdiagnostic and PTSD-specific associations with multiple forms of trauma exposure within a nation-wide sample (N = 1,649; 50% female) of military Veterans over-selected for posttraumatic stress disorder (PTSD). A higher-order Distress variable was estimated using PTSD, major depressive disorder (MDD), and generalized anxiety disorder (GAD) symptoms as indicators. A structural equation model spanning three measurement time points over an average of 3.85 years was then used to examine the unique roles of higher-order Distress and PTSD residual variance in accounting for the relations between trauma exposure and psychosocial impairment. Results suggest that the association between trauma exposure and PTSD symptoms is primarily mediated by higher-order Distress, but that PTSD severity does have a significant association with trauma exposure independent of Distress. Both higher-order Distress and PTSD-specific variance were necessary to account for the association between trauma exposure and future functional impairment. This work suggests there may be shared etiology linking cumulative trauma exposure and a range of internalizing symptoms. Continued application of higher-order dimensional models is needed to provide a more comprehensive understanding of the consequences of trauma exposure
Multiwavelength Observations of the Low Metallicity Blue Compact Dwarf Galaxy SBS 0335-052
New infrared and millimeter observations from Keck, Palomar, ISO, and OVRO
and archival data from the NRAO VLA and IRAS are presented for the low
metallicity blue compact dwarf galaxy SBS 0335-052. Mid-infrared imaging shows
this young star-forming system is compact (0.31"; 80 pc) at 12.5 microns. The
large Br-gamma equivalent width (235 Angstroms) measured from integral field
spectroscopy is indicative of a ~5 Myr starburst. The central source appears to
be optically thin in emission, containing both a warm (~80 K) and a hot (~210
K) dust component, and the overall interstellar radiation field is quite
intense, about 10,000 times the intensity in the solar neighborhood. CO
emission is not detected, though the galaxy shows an extremely high global H I
gas-to-dust mass ratio, high even for blue compact dwarfs. Finally, the
galaxy's mid-infrared-to-optical and mid-to-near-infrared luminosity ratios are
quite high, whereas its far-infrared-to-radio and far-infrared-to-optical flux
ratios are surprisingly similar to what is seen in normal star-forming
galaxies. The relatively high bolometric infrared-to-radio ratio is more easily
understood in the context of such a young system with negligible nonthermal
radio continuum emission. These new lines of evidence may outline features
common to primordial galaxies found at high redshift.Comment: 28 pages including 6 figures; accepted for publication in the
Astronomical Journa
Search for Blue Compact Dwarf Galaxies During Quiescence
Blue Compact Dwarf (BCD) galaxies are metal poor systems going through a
major starburst that cannot last for long. We have identified galaxies which
may be BCDs during quiescence (QBCD), i.e., before the characteristic starburst
sets in or when it has faded away. These QBCD galaxies are assumed to be like
the BCD host galaxies. The SDSS/DR6 database provides ~21500 QBCD candidates.
We also select from SDSS/DR6 a complete sample of BCD galaxies to serve as
reference. The properties of these two galaxy sets have been computed and
compared. The QBCD candidates are thirty times more abundant than the BCDs,
with their luminosity functions being very similar except for the scaling
factor, and the expected luminosity dimming associated with the end of the
starburst. QBCDs are redder than BCDs, and they have larger HII region based
oxygen abundance. QBCDs also have lower surface brightness. The BCD candidates
turn out to be the QBCD candidates with the largest specific star formation
rate (actually, with the largest H_alpha equivalent width). One out of each
three dwarf galaxies in the local universe may be a QBCD. The properties of the
selected BCDs and QBCDs are consistent with a single sequence in galactic
evolution, with the quiescent phase lasting thirty times longer than the
starburst phase. The resulting time-averaged star formation rate is low enough
to allow this cadence of BCD -- QBCD phases during the Hubble time.Comment: Accepted for publication in ApJ. 17 pages. 13 Fig
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