A Quantitative Non-radial Oscillation Model for the Subpulses in PSR B0943+10

In this paper, we analyze time series measurements of PSR B0943+10 and fit them with a non-radial oscillation model. The model we apply was first developed for total intensity measurements in an earlier paper, and expanded to encompass linear polarization in a companion paper to this one. We use PSR B0943+10 for the initial tests of our model because it has a simple geometry, it has been exhaustively studied in the literature, and its behavior is well-documented. As prelude to quantitative fitting, we have reanalyzed previously published archival data of PSR B0943+10 and uncovered subtle but significant behavior that is difficult to explain in the framework of the drifting spark model. Our fits of a non-radial oscillation model are able to successfully reproduce the observed behavior in this pulsar.Comment: 45 pages, 16 figures, accepted Ap

A Commentary

17 USC 105 interim-entered record; under review.It is with great interest that we read the article on the twentyfirst-century hospital ship by the esteemed Rear Adm. (ret.) Michael Baker, Mr. Jacob Baker, and Capt. (ret.) Fred “Skip” Burkle. Many of the concepts they outline are viable options worth consideration, but the future hospital ship is only one piece of the system-based, integrated approach for projecting medical power in support of Naval superiority.Identified in text as U.S. Government work

A Phase 3 Study of Evolocumab (AMG 145) in Statin-Treated Japanese Patients at High Cardiovascular Risk

Evolocumab (AMG 145), a fully human monoclonal antibody against PCSK9, significantly reduced low-density lipoprotein cholesterol (LDL-C) levels in phase 2 and 3 studies. This phase 3 study evaluated the efficacy and safety of evolocumab plus atorvastatin in Japanese patients with hyperlipidemia or mixed dyslipidemia and high cardiovascular risk. Patients were randomized to atorvastatin 5 or 20 mg/day for 4 weeks. Subsequently, patients underwent second randomization to evolocumab 140 mg biweekly (Q2W) or 420 mg monthly (QM) or placebo Q2W or QM. Coprimary end points were % change from baseline in LDL-C at week 12 and mean of weeks 10 and 12. Secondary end points included change and % change in other lipids and proportion of patients reaching LDL-C <70 mg/dl. Adverse events and laboratory values were recorded. Four hundred four patients were randomized to study drug. At baseline, the mean (SD) age was 61 (10) years (placebo) and 62 (11) years (evolocumab); 39% and 40% were women; 14% and 12% had cerebrovascular or peripheral arterial disease; and 51% and 47% had diabetes. At entry, mean (SD) calculated LDL-C was 128 (23) mg/dL; after stabilization on atorvastatin 5 and 20 mg/day, baseline LDL-C levels were 118 (35) and 94 (24) mg/dL, respectively. Mean LDL-C reductions at week 12 for evolocumab versus placebo ranged from 67% to 76%. No imbalances were observed in adverse events between treatment groups. Efficacy and safety for Q2W or QM evolocumab dosing were similar. In conclusion, in high-risk Japanese patients receiving stable statin therapy, evolocumab markedly reduced LDL-C and was well tolerated

Ultrasound-triggered antibiotic release from PEEK clips to prevent spinal fusion infection: Initial evaluations.

Despite aggressive peri-operative antibiotic treatments, up to 10% of patients undergoing instrumented spinal surgery develop an infection. Like most implant-associated infections, spinal infections persist through colonization and biofilm formation on spinal instrumentation, which can include metal screws and rods for fixation and an intervertebral cage commonly comprised of polyether ether ketone (PEEK). We have designed a PEEK antibiotic reservoir that would clip to the metal fixation rod and that would achieve slow antibiotic release over several days, followed by a bolus release of antibiotics triggered by ultrasound (US) rupture of a reservoir membrane. We have found using human physiological fluid (synovial fluid), that higher levels (100–500 μg) of vancomycin are required to achieve a marked reduction in adherent bacteria vs. that seen in the common bacterial medium, trypticase soy broth. To achieve these levels of release, we applied a polylactic acid coating to a porous PEEK puck, which exhibited both slow and US-triggered release. This design was further refined to a one-hole or two-hole cylindrical PEEK reservoir that can clip onto a spinal rod for clinical use. Short-term release of high levels of antibiotic (340 ± 168 μg), followed by US-triggered release was measured (7420 ± 2992 μg at 48 h). These levels are sufficient to prevent adhesion of Staphylococcus aureus to implant materials. This study demonstrates the feasibility of an US-mediated antibiotic delivery device, which could be a potent weapon against spinal surgical site infection. Statement of Significance: Spinal surgical sites are prone to bacterial colonization, due to presence of instrumentation, long surgical times, and the surgical creation of a dead space (≥5 cm 3 ) that is filled with wound exudate. Accordingly, it is critical that new approaches are developed to prevent bacterial colonization of spinal implants, especially as neither bulk release systems nor controlled release systems are available for the spine. This new device uses non-invasive ultrasound (US) to trigger bulk release of supra-therapeutic doses of antibiotics from materials commonly used in existing surgical implants. Thus, our new delivery system satisfies this critical need to eradicate surviving bacteria, prevent resistance, and markedly lower spinal infection rates

Massive Star Formation in the Molecular Ring Orbiting the Black Hole at the Galactic Center

A ring of dense molecular gas extending 2-7 pc orbits the supermassive black hole Sgr A* at the center of our Galaxy. Using the Green Bank Telescope, we detected water maser lines and both narrow (0.35 km/s) and broad (30 - 50 km/s) methanol emission from the molecular ring. Two of the strongest methanol lines at 44 GHz are confirmed as masers by interferometric observations. These class I methanol masers are collisionally excited and are signatures of early phases of massive star formation in the disk of the Galaxy, suggesting that star formation in the molecular ring is in its early phase. Close inspection of the kinematics of the associated molecular clumps in the HCN (J=1-0) line reveals broad red-shifted wings indicative of disturbance by protostellar outflows from young (few times 10^4 yr), massive stars embedded in the clumps. The thermal methanol profile has a similar shape, with a narrow maser line superimposed on a broad, red-shifted wing. Additional evidence for the presence of young massive protostars is provided by shocked molecular hydrogen and a number of striking ionized and molecular linear filaments in the vicinity of methanol sources suggestive of 0.5-pc scale protostellar jets. Given that the circumnuclear molecular ring is kinematically unsettled and thus is likely be the result of a recent capture, the presence of both methanol emission and broad, red-shifted HCN emission suggests that star formation in the circumnuclear ring is in its infancy.Comment: 13 pages, 4 figures, ApJ Letters (in press

A Pulsational Model for the Orthogonal Polarization Modes in Radio Pulsars

In an earlier paper, we introduced a model for pulsars in which non-radial oscillations of high spherical degree (\el) aligned to the magnetic axis of a spinning neutron star were able to reproduce subpulses like those observed in single-pulse measurements of pulsar intensity. The model did not address polarization, which is an integral part of pulsar emission. Observations show that many pulsars emit radio waves that appear to be the superposition of two linearly polarized emission modes with orthogonal polarization angles. In this paper, we extend our model to incorporate linear polarization. As before, we propose that pulsational displacements of stellar material modulate the pulsar emission, but now we apply this modulation to a linearly-polarized mode of emission, as might be produced by curvature radiation. We further introduce a second polarization mode, orthogonal to the first, that is modulated by pulsational velocities. We combine these modes in superposition to model the observed Stokes parameters in radio pulsars.Comment: 19 pages, 4 figures accepted Ap

Incorporating interactive 3-dimensional graphics in astronomy research papers

Most research data collections created or used by astronomers are intrinsically multi-dimensional. In contrast, all visual representations of data presented within research papers are exclusively 2-dimensional. We present a resolution of this dichotomy that uses a novel technique for embedding 3-dimensional (3-d) visualisations of astronomy data sets in electronic-format research papers. Our technique uses the latest Adobe Portable Document Format extensions together with a new version of the S2PLOT programming library. The 3-d models can be easily rotated and explored by the reader and, in some cases, modified. We demonstrate example applications of this technique including: 3-d figures exhibiting subtle structure in redshift catalogues, colour-magnitude diagrams and halo merger trees; 3-d isosurface and volume renderings of cosmological simulations; and 3-d models of instructional diagrams and instrument designs.Comment: 18 pages, 7 figures, submitted to New Astronomy. For paper with 3-dimensional embedded figures, see http://astronomy.swin.edu.au/s2plot/3dpd

Observations of Non-radial Pulsations in Radio Pulsars

We introduce a model for pulsars in which non-radial oscillations of high spherical degree (l) aligned to the magnetic axis of a spinning neutron star reproduce the morphological features of pulsar beams. In our model, rotation of the pulsar carries a pattern of pulsation nodes underneath our sightline, reproducing the longitude stationary structure seen in average pulse profiles, while the associated time-like oscillations reproduce "drifting subpulses"--features that change their longitude between successive pulsar spins. We will show that the presence of nodal lines can account for observed 180 degree phase jumps in drifting subpulses and their otherwise poor phase stability, even if the time-like oscillations are strictly periodic. Our model can also account for the "mode changes" and "nulls" observed in some pulsars as quasiperiodic changes between pulsation modes of different l or radial overtone n, analogous to pulsation mode changes observed in oscillating white dwarf stars. We will discuss other definitive and testable requirements of our model and show that they are qualitatively supported by existing data. While reserving judgment until the completion of quantitative tests, we are inspired enough by the existing observational support for our model to speculate about the excitation mechanism of the non-radial pulsations, the physics we can learn from them, and their relationship to the period evolution of pulsars.Comment: 28 pages, 9 figures (as separate png files), Astrophysical Journal, in pres

Genetically engineered E. coli Nissle attenuates hyperammonemia and prevents memory impairment in bile‐duct ligated rats

Hyperammonemia associated with chronic liver disease (CLD) is implicated in the pathogenesis of hepatic encephalopathy (HE). The gut is a major source of ammonia production that contributes to hyperammonemia in CLD and HE and remains the primary therapeutic target for lowering hyperammonemia. As an ammonia‐lowering strategy, Escherichia coli Nissle 1917 bacterium was genetically modified to consume and convert ammonia to arginine (S‐ARG). S‐ARG was further modified to additionally synthesize butyrate (S‐ARG+BUT). Both strains were evaluated in bile‐duct ligated (BDL) rats; experimental model of CLD and HE. Methods One‐week post‐surgery, BDLs received non‐modified EcN (EcN), S‐ARG, S‐ARG+BUT (3x1011 CFU/day) or vehicle until sacrifice at 3‐ or 5‐weeks. Plasma (ammonia/pro‐inflammatory/liver‐function), liver fibrosis (hydroxyproline), liver mRNA (pro‐inflammatory/fibrogenic/anti‐apoptotic) and colon mRNA (pro‐inflammatory) biomarkers were measured post‐sacrifice. Memory, motor‐coordination, muscle‐strength, and locomotion were assessed at 5‐weeks. Results In BDL‐Veh rats, hyperammonemia developed at 3‐ and further increased at 5‐weeks. This rise was prevented by S‐ARG and S‐ARG+BUT, whereas EcN was ineffective. Memory impairment was prevented only in S‐ARG+BUT vs BDL‐Veh. Systemic inflammation (IL‐10/MCP‐1/endotoxin) increased at 3‐ and 5‐weeks in BDL‐Veh. S‐ARG+BUT attenuated inflammation at both timepoints (except 5‐week endotoxin) vs BDL‐Veh, whereas S‐ARG only attenuated IP‐10 and MCP‐1 at 3‐weeks. Circulating (ALT/AST/ALP/GGT/albumin/bilirubin) and gene expression liver‐function markers (IL‐10/IL‐6/IL‐1β/TGF‐β/α‐SMA/collagen‐1α1/Bcl‐2) were not normalized by either strain. Colonic mRNA (TNF‐α/IL‐1β/occludin) markers were attenuated by synthetic strains at both timepoints vs BDL‐Veh. Conclusion S‐ARG and S‐ARG+BUT attenuated hyperammonemia, with S‐ARG+BUT additional memory protection likely due to greater anti‐inflammatory effect. These innovative strategies, particularly S‐ARG+BUT, have potential to prevent HE

The Rosette Eye: the key transition phase in the birth of a massive star

Massive protostars dramatically influence their surroundings via accretion-induced outflows and intense radiation fields. They evolve rapidly, the disk and infalling envelope being evaporated and dissipated in $\sim$ 10$^5$ years. Consequently, they are very rare and investigating this important phase of early stellar evolution is extremely difficult. Here we present the discovery of a key transient phase in the emergence of a massive young star, in which ultraviolet radiation from the new-born giant has just punctured through its natal core. The massive young stellar object AFGL 961 II is readily resolved in the near infrared. Its morphology closely resembles a cat's eye and is here dubbed as the Rosette Eye. Emerging ionized flows blow out an hourglass shaped nebula, which, along with the existence of strong near-infrared excess, suggests the existence of an accretion disk in the perpendicular direction. The lobes of the hourglass, however, are capped with arcs of static H$_{2}$ emission produced by fluorescence. This study has strong implications for our understanding of how massive stars embark on their formation.Comment: 3 figure