A palaeolimnological study of Loch Shin, Scotland. Final report to SEPA and the Forestry Commission

This project reports on analysis of a sediment core collected from the lower basin of Loch Shin in Sutherland, Scotland on 24 August 2015, spanning a total sediment depth of 31.5 cm. Palaeoecological techniques, principally diatom analysis of a dated core, were employed to assess environmental change at the loch since 1850 AD. The project aims to determine the reference conditions of the loch and to establish the onset, rate and magnitude of any changes in the diatom flora. The Scottish Environment Protection Agency are particularly interested in any changes in the loch that may have occurred in association with fish farming and forestry practices and whether the hydropower scheme has had any impact. Radiometric methods were applied to the core in order to date the recent sediments, revealing that the 31.5 cm core dates back to ~1850 AD. There is an increase in sedimentation rates before the 1920s, followed by small changes around a mean value of 0.026 g cm-2 yr-1 until the 2000s, after which the sedimentation rates increase slightly again in recent years to 0.038 g cm-2 yr-1. Diatom analysis was carried out on 21 samples distributed throughout the core and a diatom-total phosphorus (TP) transfer function was applied to the diatom data to reconstruct trophic status. There were marked changes in the diatom assemblages during the 160 year period represented by the core and cluster analysis revealed four major zones with the most significant split, reflecting floristic change, at 7.75 cm which corresponds to 1994. In the period from 1860 to 1930 (Zone 1), the sedimentary diatom assemblages of Loch Shin were very stable with a diatom flora typical of nutrient-poor, deep lakes and the diatom-inferred TP concentrations were low and stable at 5 μg L−1 indicating oligotrophic conditions. The diatom reference conditions of Loch Shin can thus be described as a community of oligotrophic, acidophilous-circumneutral taxa, particularly Cyclotella kuetzingiana, Achnanthidium minutissimum and Brachysira vitrea. The diatom assemblages began to change from ~1930 with the arrival of taxa more typically associated with mesotrophic waters, namely Aulacoseira subarctica and Asterionella formosa, marking an initial enrichment phase (Zone 2). The progressive and gradual nature of the shifts suggests a response to the cumulative effect of increasing pressures in the catchment during the mid to late twentieth century including dam construction and the consequent water level rise in the 1950s, as well as forestry plantation and fertilisation which took place from the 1960s. A more pronounced enrichment phase was evident from the mid-1990s with the expansion of Aulacoseira subarctica, the arrival of Fragilaria crotonensis and the decline, and in some cases the loss, of numerous taxa seen in the early part of the record (Zone 3). The diatom-inferred TP concentrations increased to 16 μg L−1. While the exact causes of these shifts cannot be established, the most marked changes in the diatoms are coincident with the arrival of the fish farms on the loch in 1994-1995 suggesting that aquaculture may have played a role. Since 2009 Fragilaria crotonensis has disappeared although the reasons for this are not clear (Zone 4). A. subarctica remains the dominant species and the planktonic component of the assemblages remains high at 50-60%. The diatom-inferred TP concentrations decreased to 11 μg L-1 at the core surface, indicating that there may be a recent phase of reduction in trophic status. However, given that there are no reported changes in land use or management since 2009 and that diatoms respond to a host of factors in addition to nutrient concentrations, it would be unwise to suggest that the disappearance of F. crotonensis from the recent sediment record is reflective of improving water quality. Clearly a more detailed study of recent management practices in the catchment and fish farms is required to establish whether there have been any real reductions in nutrient loads to the loch

Closing the brief case: A Fatal Case of Necrotizing Fasciitis Due to Multidrug-Resistant Acinetobacter baumannii

ANSWERS TO SELF-ASSESSMENT QUESTIONS 1. What is the most common etiology of monomicrobial (type 2) necrotizing fasciitis? a. Acinetobacter baumannii b. Staphylococcus aureus c. Streptococcus pyogenes d. Vibrio vulnificus Answer: c. Although all of the organisms listed cause type 2 necrotizing fasciitis, the most common cause is still S. pyogenes, with an incidence of 0.4 per 100,000 in the United States. Due to variations in reporting practices, the exact incidences of other etiologies are not known, but they are less common than S. pyogenes

Fermi-surface topology of the iron pnictide LaFe2_2P2_2

We report on a comprehensive de Haas--van Alphen (dHvA) study of the iron pnictide LaFe$_2$P$_2$. Our extensive density-functional band-structure calculations can well explain the measured angular-dependent dHvA frequencies. As salient feature, we observe only one quasi-two-dimensional Fermi-surface sheet, i.e., a hole-like Fermi-surface cylinder around $\Gamma$, essential for $s_\pm$ pairing, is missing. In spite of considerable mass enhancements due to many-body effects, LaFe$_2$P$_2$ shows no superconductivity. This is likely caused by the absence of any nesting between electron and hole bands.Comment: 5 pages, 4 figure

Fermi Surface Properties of Low Concentration Cex_{x}La1−x_{1-x}B6_{6}: dHvA

The de Haas-van Alphen effect is used to study angular dependent extremal areas of the Fermi Surfaces (FS) and effective masses of Ce$_{x}$La$_{1-x}$B$_{6}$ alloys for $x$ between 0 and 0.05. The FS of these alloys was previously observed to be spin polarized at low Ce concentration ($x$ = 0.05). This work gives the details of the initial development of the topology and spin polarization of the FS from that of unpolarized metallic LaB$_{6}$ to that of spin polarized heavy Fermion CeB$_{6}$ .Comment: 7 pages, 9 figures, submitted to PR

On the de Haas-van Alphen effect in inhomogeneous alloys

We show that Landau level broadening in alloys occurs naturally as a consequence of random variations in the local quasiparticle density, without the need to consider a relaxation time. This approach predicts Lorentzian-broadened Landau levels similar to those derived by Dingle using the relaxation-time approximation. However, rather than being determined by a finite relaxation time $\tau$, the Landau-level widths instead depend directly on the rate at which the de Haas-van Alphen frequency changes with alloy composition. The results are in good agreement with recent data from three very different alloy systems.Comment: 5 pages, no figure

Gas Dynamics in the LINER Galaxy NGC 5005: Episodic Fueling of a Nuclear Disk

We report high-resolution CO(1-0) observations in the central 6 kpc of the LINER galaxy NGC 5005 with the Owens Valley Radio Observatory millimeter array. Molecular gas is distributed in three components - a ring at a radius of about 3 kpc, a strong central condensation, and a stream to the northwest of the nucleus but inside the 3 kpc ring. The central condensation is a disk of about 1 kpc radius with a molecular gas mass of 2 x 10^9 M_sun. The stream between the 3 kpc ring and the nuclear disk lies on a straight dust lane seen in the optical. If this material moves in the plane of the galaxy, it has a velocity offset by up to ~ 150 km/s from galactic rotation. We suggest that an optically inconspicuous stellar bar lying within the 3 kpc ring can explain the observed gas dynamics. This bar is expected to connect the nuclear disk and the ring along the position angle of the northwest stream. A position-velocity cut in this direction reveals features which match the characteristic motions of gas in a barred potential. Our model indicates that gas in the northwest stream is on an x_1 orbit at the bar's leading edge; it is falling into the nucleus with a large noncircular velocity, and will eventually contribute about 2 x 10^8 M_sun to the nuclear disk. If most of this material merges with the disk on its first passage of pericenter, the gas accretion rate during the collision will be 50 M_sun/yr. We associate the nuclear disk with an inner 2:1 Lindblad resonance, and the 3 kpc ring with an inner 4:1 Lindblad resonance. The high rate of bar-driven inflow and the irregular appearance of the northwest stream suggest that a major fueling event is in progress in NGC 5005. Such episodic (rather than continuous) gas supply can regulate the triggering of starburst and accretion activity in galactic nuclei. (abridged)Comment: 26 pages, 12 figures, AASTeX, ApJ in press (Feb. 10, 2000). For full-resolution figures, see http://www.ovro.caltech.edu/mm/science/science.htm

TOP2A and EZH2 Provide Early Detection of an Aggressive Prostate Cancer Subgroup.

Purpose: Current clinical parameters do not stratify indolent from aggressive prostate cancer. Aggressive prostate cancer, defined by the progression from localized disease to metastasis, is responsible for the majority of prostate cancer–associated mortality. Recent gene expression profiling has proven successful in predicting the outcome of prostate cancer patients; however, they have yet to provide targeted therapy approaches that could inhibit a patient\u27s progression to metastatic disease. Experimental Design: We have interrogated a total of seven primary prostate cancer cohorts (n = 1,900), two metastatic castration-resistant prostate cancer datasets (n = 293), and one prospective cohort (n = 1,385) to assess the impact of TOP2A and EZH2 expression on prostate cancer cellular program and patient outcomes. We also performed IHC staining for TOP2A and EZH2 in a cohort of primary prostate cancer patients (n = 89) with known outcome. Finally, we explored the therapeutic potential of a combination therapy targeting both TOP2A and EZH2 using novel prostate cancer–derived murine cell lines. Results: We demonstrate by genome-wide analysis of independent primary and metastatic prostate cancer datasets that concurrent TOP2A and EZH2 mRNA and protein upregulation selected for a subgroup of primary and metastatic patients with more aggressive disease and notable overlap of genes involved in mitotic regulation. Importantly, TOP2A and EZH2 in prostate cancer cells act as key driving oncogenes, a fact highlighted by sensitivity to combination-targeted therapy. Conclusions: Overall, our data support further assessment of TOP2A and EZH2 as biomarkers for early identification of patients with increased metastatic potential that may benefit from adjuvant or neoadjuvant targeted therapy approaches. ©2017 AACR

Orbiter escape pole

A Shuttle type of aircraft (10) with an escape hatch (12) has an arcuately shaped pole housing (16) attachable to an interior wall and ceiling with its open end adjacent to the escape hatch. The pole housing 16 contains a telescopically arranged and arcuately shaped primary pole member (22) and extension pole member (23) which are guided by roller assemblies (30,35). The extension pole member (23) is slidable and extendable relative to the primary pole member (22). For actuation, a spring actuated system includes a spring (52) in the pole housing. A locking member (90) engages both pole members (22,23) through notch portions (85,86) in the pole members. The locking member selectively releases the extension pole member (23) and the primary pole member (22). An internal one-way clutch or anti-return mechanism prevents retraction of the extension pole member from an extended position. Shock absorbers (54)(150,152) are for absoring the energy of the springs. A manual backup deployment system is provided which includes a canted ring (104) biased by a spring member (108). A lever member (100) with a slot and pin connection (102) permits the mechanical manipulation of the canted ring to move the primary pole member. The ring (104) also prevents retraction of the main pole. The crew escape mechanism includes a magazine (60) and a number of lanyards (62), each lanyard being mounted by a roller loop (68) over the primary pole member (22). The strap on the roller loop has stitching for controlled release, a protection sheath (74) to prevent tangling and a hook member (69) for attachment to a crew harness

The Broadband Afterglow of GRB980329

We present radio observations of the afterglow of the bright gamma-ray burst GRB980329 made between one month and several years after the burst, a re-analysis of previously published submillimeter data, and late-time optical and near-infrared (NIR) observations of the host galaxy. From the absence of a spectral break in the optical/NIR colors of the host galaxy, we exclude the earlier suggestion that GRB980329 lies at a redshift of z >~5. We combine our data with the numerous multi-wavelength observations of the early afterglow, fit a comprehensive afterglow model to the entire broadband dataset, and derive fundamental physical parameters of the blast-wave and its host environment. Models for which the ejecta expand isotropically require both a high circumburst density and extreme radiative losses from the shock. No low density model (n << 10 cm^{-3}) fits the data. A burst with a total energy of ~ 10^{51} erg, with the ejecta narrowly collimated to an opening angle of a few degrees, driven into a surrounding medium with density ~ 20 cm^{-3}, provides a satisfactory fit to the lightcurves over a range of redshifts.Comment: 27 pages, incl. 6 figures, minor revisions (e.g. added/updated references) Accepted by Ap

The Discovery and Broad-band Follow-up of the Transient Afterglow of GRB 980703

We report on the discovery of the radio, infrared and optical transient coincident with an X-ray transient proposed to be the afterglow of GRB 980703. At later times when the transient has faded below detection, we see an underlying galaxy with R=22.6; this galaxy is the brightest host galaxy (by nearly 2 magnitudes) of any cosmological GRB thus far. In keeping with an established trend, the GRB is not significantly offset from the host galaxy. Interpreting the multi-wavelength data in the framework of the popular fireball model requires that the synchrotron cooling break was between the optical and X-ray bands on July 8.5 UT and that the intrinsic extinction of the transient is Av=0.9. This is somewhat higher than the extinction for the galaxy as a whole, as estimated from spectroscopy.Comment: 5 pages, 3 figures, and 2 tables. Submitted to the Astrophysical Journal Letters on 27 August 199