Life History of Elsinoe panici

Elsinoe panici Tiffany and Mathre is widespread on native Panicum virgatum L. in Iowa. In June Sphaceloma (imperfect stage) conidia develop from acervuli on overwintered stromata of wind-dispersed leaf litter and culms. Germ cubes penetrate between epidermal cells of young leaves, and 2 wk later tiny yellowish, subepidermal stromata are visible. Secondary conidia develop from acervuli on these stromata within 2 wk and are spread to adjacent leaves. Stromata become black, raised, shiny, ovoid-elongate patches, composed of thick-walled pseudoparenchymatous cells. Chlorosis or necrosis does not develop around the stromata. Stromata are visible on all leaves throughout the season. Acervuli, appearing as white spots in black stromata, open by irregular tears in the epidermis. Ascostromata develop on lower leaves infrequently from late July into September. They are tan-bronze, raised, ovoid-elongate, softer, and more loosely structured than stromata. Asci mature at different times. Ascospores are discharged from the bitunicate asci and germinate directly by budding or by germ tubes

Emerging magnetic resonance imaging techniques and analysis methods in amyotrophic lateral sclerosis

Objective markers of disease sensitive to the clinical activity, symptomatic progression, and underlying substrates of neurodegeneration are highly coveted in amyotrophic lateral sclerosis in order to more eloquently stratify the highly heterogeneous phenotype and facilitate the discovery of effective disease modifying treatments for patients. Magnetic resonance imaging (MRI) is a promising, non-invasive biomarker candidate whose acquisition techniques and analysis methods are undergoing constant evolution in the pursuit of parameters which more closely represent biologically-applicable tissue changes. Neurite Orientation Dispersion and Density Imaging (NODDI; a form of diffusion imaging), and quantitative Magnetization Transfer Imaging (qMTi) are two such emerging modalities which have each broadened the understanding of other neurological disorders and have the potential to provide new insights into structural alterations initiated by the disease process in ALS. Furthermore, novel neuroimaging data analysis approaches such as Event-Based Modeling (EBM) may be able to circumvent the requirement for longitudinal scanning as a means to comprehend the dynamic stages of neurodegeneration . Combining these and other innovative imaging protocols with more sophisticated techniques to analyse ever-increasing datasets holds the exciting prospect of transforming understanding of the biological processes and temporal evolution of the ALS syndrome, and can only benefit from multicentre collaboration across the entire ALS research community

The Host Galaxies of Narrow-Line Seyfert 1s: Evidence for Bar-Driven Fueling

We present a study of the host-galaxy morphologies of narrow- and broad-line Seyfert 1 galaxies (NLS1s and BLS1s) based on broad-band optical images from the Hubble Space Telescope archives. We find that large-scale stellar bars, starting at ~1 kpc from the nucleus, are much more common in NLS1s than BLS1s. Furthermore, the fraction of NLS1 spirals that have bars increases with decreasing full-width at half-maximum (FWHM) of the broad component of H-beta. These results suggest a link between the large-scale bars, which can support high fueling rates to the inner kpc, and the high mass-accretion rates associated with the supermassive black holes in NLS1s.Comment: 19 pages, 4 figures (1a, 1b, 2, and 3), Accepted for publication in the Astronomical Journa

Dynamic Singularities in Cooperative Exclusion

We investigate cooperative exclusion, in which the particle velocity can be an increasing function of the density. Within a hydrodynamic theory, an initial density upsteps and downsteps can evolve into: (a) shock waves, (b) continuous compression or rarefaction waves, or (c) a mixture of shocks and continuous waves. These unusual phenomena arise because of an inflection point in the current versus density relation. This anomaly leads to a group velocity that can either be an increasing or a decreasing function of the density on either side of these wave singularities.Comment: 4 pages, 4 figures, 2 column revtex 4-1 format; version 2: substantially rewritten and put in IOP format, mail results unchanged; version 3: minor changes, final version for publication in JSTA

Evolving Regulation of Corporate Governance and the Implications for D&O Liability: The United States and Australia

This Article compares the modern corporate regulatory environments in the United States and Australia, including an analysis of the climate for Directors & Officers (D & O) liability coverage. Comparing these regulations across two large markets with similar historical bases for assessing director and officer liability allows us to explore which reforms may be more effective as new scandals emerge

Raman and fluorescence contributions to resonant inelastic soft x-ray scattering on LaAlO3_3/SrTiO3_3 heterostructures

We present a detailed study of the Ti 3$d$ carriers at the interface of LaAlO$_3$/SrTiO$_3$ heterostructures by high-resolution resonant inelastic soft x-ray scattering (RIXS), with special focus on the roles of overlayer thickness and oxygen vacancies. Our measurements show the existence of interfacial Ti 3$d$ electrons already below the critical thickness for conductivity and an increase of the total interface charge up to a LaAlO$_3$ overlayer thickness of 6 unit cells before it levels out. By comparing stoichiometric and oxygen deficient samples we observe strong Ti 3$d$ charge carrier doping by oxygen vacancies. The RIXS data combined with photoelectron spectroscopy and transport measurements indicate the simultaneous presence of localized and itinerant charge carriers. However, it is demonstrated that the relative amount of localized and itinerant Ti $3d$ electrons in the ground state cannot be deduced from the relative intensities of the Raman and fluorescence peaks in excitation energy dependent RIXS measurements, in contrast to previous interpretations. Rather, we attribute the observation of either the Raman or the fluorescence signal to the spatial extension of the intermediate state reached in the RIXS excitation process.Comment: 9 pages, 6 figure

The Narrow-Line Regions of LINERs as Resolved with the Hubble Space Telescope

LINERs exist in the nuclei of a large fraction of luminous galaxies, but their connection with the AGN phenomenon has remained elusive. We present Hubble Space Telescope narrowband [O III]5007 and H-alpha+[N II] emission-line images of the central regions of 14 galaxies with LINER nuclei. The compact, ~1 arcsec-scale, unresolved emission that dominates the line flux in ground-based observations is mostly resolved by HST. The bulk of this emission comes from regions with sizes of tens to hundreds of parsecs that are resolved into knots, filaments, and diffuse gas whose morphology differs from galaxy to galaxy. Most of the galaxies do not show clear linear structures or ionization cones analogous to those often seen in Seyfert galaxies. An exception is NGC 1052, the prototypical LINER, in which we find a 3 arcsec-long (~ 250 pc) biconical structure that is oriented on the sky along the galaxy's radio jet axis. Seven of the galaxies have been shown in previously published HST images to have a bright compact ultraviolet nuclear source, while the other seven do not have a central UV source. Our images find evidence of dust in the nuclear regions of all 14 galaxies, with clear indications of nuclear obscuration in most of the "UV-dark" cases. The data suggest that the line-emitting gas in most LINERs is photoionized by a central source (which may be stellar, nonstellar, or a combination thereof) but that this source is often hidden from direct view. We find no obvious morphological differences between LINERs with detected weak broad H-alpha wings in their spectra and those with only narrow lines. Likewise, there is no clear morphological distinction between objects whose UV spectra are dominated by hot stars (e.g., NGC 4569) and those that are AGN-like (e.g., NGC 4579).Comment: Accepted for publication in the ApJ. 25 pages, 3 tables, 9 JPEG Figure