The Roles of Extrinsic and Intrinsic Factors in the Freshwater Life-History Dynamics of a Migratory Salmonid

Key life-cycle transitions, such as metamorphosis or migration, can be altered by a variety of external factors, such as climate variation, strong species interactions, and management intervention, or modulated by density dependence. Given that these life-history transitions can influence population dynamics, understanding the simultaneous effects of intrinsic and extrinsic controls on life-history expression is particularly relevant for species of management or conservation importance. Here, we examined how life histories of steelhead (Oncorhynchus mykiss) are affected by weather, pink salmon abundance (Oncorhynchus gorbuscha), experimental nutrient addition, and density-dependent processes. We tested for impacts on the size of steelhead smolts (juveniles migrating to the sea), as well as their age and abundance across four decades in the Keogh River, British Columbia, Canada. Larger steelhead smolts were associated with warmer years and artificial nutrient addition. In addition, higher pink salmon abundance and artificial nutrient addition correlated with juvenile steelhead migrating at younger ages. While density dependence appeared to be the primary factor regulating the abundance of steelhead smolts, nutrient addition and temperature were positively and negatively associated with smolt production, respectively, prior to 1991, and pink salmon spawning abundance was positively associated with smolt production after 1990. Thus, this study provides evidence that the temporal dynamics of one species of salmon is linked to the juvenile life history of co-occurring steelhead. A complex interplay of species interactions, nutrient subsidies, density dependence, and climatic variation can control the life-history expression of species with complex life cycles

Three-Dimensional Simulations of Magnetized Thin Accretion Disks around Black Holes: Stress in the Plunging Region

We describe three-dimensional general relativistic magnetohydrodynamic simulations of a geometrically thin accretion disk around a non-spinning black hole. The disk has a thickness $h/r\sim0.05-0.1$ over the radial range $(2-20)GM/c^2$. In steady state, the specific angular momentum profile of the inflowing magnetized gas deviates by less than 2% from that of the standard thin disk model of Novikov & Thorne (1973). Also, the magnetic torque at the radius of the innermost stable circular orbit (ISCO) is only $\sim2$ of the inward flux of angular momentum at this radius. Both results indicate that magnetic coupling across the ISCO is relatively unimportant for geometrically thin disks.Comment: 4 pages, 4 figures, ApJL accepte

Outpatient prescription practices in patients with atrial fibrillation (from the NCDR PINNACLE registry)

This study sought to evaluate inappropriate prescribing practices in an atrial fibrillation (AF) population, as outlined by the 2016 ACC/AHA Clinical Performance and Quality Measures for Adults with Atrial Fibrillation or Atrial Flutter document. The 2016 AF quality measures document specified medications to avoid in certain AF populations, including aspirin and anticoagulant combination therapy in patients without cardiovascular disease, and non-dihydropyridine calcium channel blockers in patients with reduced ejection fraction. Using data from the NCDR PINNACLE registry, a national outpatient cardiology practice registry, we assessed rates of inappropriate prescription of two types of medications among AF outpatients from 5/1/2008-5/1/2016. Overall rates of inappropriate prescription and variation by practice were calculated. Patient and practice factors associated with inappropriate prescription were assessed in adjusted analyses. A total of 107,759 of 658,250 (16.4%) patients without cardiovascular disease were inappropriately prescribed an antiplatelet and anticoagulant together, and 5,731 of 150,079 (3.8%) patients with reduced ejection fraction were inappropriately prescribed a non-dihydropyridine calcium channel blocker. Overall, 14.8% of AF patients were prescribed medications that were not recommended. Both patient and practice factors were associated with inappropriate prescribing, and the adjusted practice-level median odds ratio for inappropriate prescription was 1.70 (95% CI: 1.61-1.82), indicating a 70% likelihood that 2 random practices would treat identical AF patients differently. In a large registry of AF patients treated in cardiology practices, overall rates of inappropriate prescription practices, as defined by the 2016 AF quality measures, were relatively low, but significant practice variation was present

Variability of extracorporeal cardiopulmonary resuscitation utilization for refractory adult out-of-hospital cardiac arrest: an international survey study.

Objective: A growing interest in extracorporeal cardiopulmonary resuscitation (ECPR) as a rescue strategy for refractory adult out-of-hospital cardiac arrest (OHCA) currently exists. This study aims to determine current standards of care and practice variation for ECPR patients in the USA and Korea. Methods: In December 2015, we surveyed centers from the Korean Hypothermia Network (KORHN) Investigators and the US National Post-Arrest Research Consortium (NPARC) on current targeted temperature management and ECPR practices. This project analyzes the subsection of questions addressing ECPR practices. We summarized survey. Results: Overall, 9 KORHN and 4 NPARC centers reported having ECPR programs and had complete survey data available. Two KORHN centers utilized extracorporeal membrane oxygenation only for postarrest circulatory support in patients with refractory shock and were excluded from further analysis. Centers with available ECPR generally saw a high volume of OHCA patients (10/11 centers care for \u3e75 OHCA a year). Location of, and providers trained for cannulation varied across centers. All centers in both countries (KORHN 7/7, NPARC 4/4) treated comatose ECPR patients with targeted temperature management. All NPARC centers and four of seven KORHN centers reported having a standardized hospital protocol for ECPR. Upper age cutoff for eligibility ranged from 60 to 75 years. No absolute contraindications were unanimous among centers. Conclusion: A wide variability in practice patterns exist between centers performing ECPR for refractory OHCA in the US and Korea. Standardized protocols and shared research databases might inform best practices, improve outcomes, and provide a foundation for prospective studies

Amici Curiae Brief of the International Municipal Lawyers Association and Legal Scholars in Support of Defendants-Appellees in Portland Pipe Line Corporation, et al. v. City of South Portland, et al.

This brief to the Maine Supreme Judicial Court was filed in support of the City of South Portland by the Amici Curiae, including the International Municipal Lawyers Association and legal scholars, to provide the Court with a background on the role of local governments in land use planning, and to explain why the City of South Portland’s Clear Skies Ordinance falls easily within the City’s authority and was not preempted by state legislation.After studying the potential for bulk loading of crude oil within its boundaries, the City of South Portland concluded that the infrastructure requirements and environmental impacts of the activity posed a threat to public health and welfare and were incompatible with the community’s vision of itself for the future. The City therefore decided to enact the Clear Skies Ordinance, which prohibits the storing and handling of petroleum or petroleum products for the bulk loading of crude oil onto any marine tank vessel in specified zoning districts. Litigation followed, with plaintiffs arguing that the City lacked authority to enact the Ordinance and that, even if it had such authority in the first instance, that authority had been preempted by other state law. Defendants prevailed on summary judgment in the U.S. District Court for the District of Maine, and during the course of an appeal to the United States Court of Appeals for the First Circuit, the Circuit certified several questions to the Maine Supreme Judicial Court. This brief was filed in support of the City with regard to those certified questions.The brief begins by discussing how central the role of local governments is in making land use decisions, emphasizing the highly localized impacts of land use decisions for public health and welfare. It then describes the zoning mechanisms by which local governments exercise their land use power, and discusses why the zoning power is so important for protecting public health and environmental quality, and responding to the changing needs of communities.Next, the brief explains the legal underpinnings of the City of South Portland’s home rule authority. The Constitution of the State of Maine contains a broad grant of home rule authority that is further strengthened by a statutorily imposed rebuttable presumption of validity for exercises of that authority. Local exercises of zoning authority are consistent within this home rule grant, and the brief discusses why the Clear Skies Ordinance falls squarely within the local zoning power. Finally, the brief explains why the Ordinance has not been expressly or impliedly preempted by state law. For all of those reasons, the brief concludes that the City’s enactment of the Ordinance was valid in the first instance and should not be overturned

Advection-Dominated Accretion Model of Sagittarius A*: Evidence for a Black Hole at the Galactic Center

Sgr A* at the Galactic Center is a puzzling source. It has a mass M=(2.5+/-0.4) x 10^6 solar masses which makes it an excellent black hole candidate. Observations of stellar winds and other gas flows in its vicinity suggest a mass accretion rate approximately few x 10^{-6} solar masses per year. However, such an accretion rate would imply a luminosity > 10^{40} erg/s if the radiative efficiency is the usual 10 percent, whereas observations indicate a bolometric luminosity <10^{37} erg/s. The spectrum of Sgr A* is unusual, with emission extending over many decades of wavelength. We present a model of Sgr A* which is based on a two-temperature optically-thin advection-dominated accretion flow. The model is consistent with the estimated mass and accretion rate, and fits the observed fluxes in the cm/mm and X-ray bands as well as upper limits in the sub-mm and infrared bands; the fit is less good in the radio below 86 GHz and in gamma-rays above 100 MeV. The very low luminosity of Sgr A* is explained naturally in the model by means of advection. Most of the viscously dissipated energy is advected into the central mass by the accreting gas, and therefore the radiative efficiency is extremely low, approximately 5 x 10^{-6}. A critical element of the model is the presence of an event horizon at the center which swallows the advected energy. The success of the model could thus be viewed as confirmation that Sgr A* is a black hole.Comment: 41 pages (Latex) including 6 Figures and 2 Tables. Final Revised Version changes to text, tables and figures. ApJ, 492, in pres

Prograde and Retrograde Black Holes: Whose Jet is More Powerful?

The outflow efficiency (eta) from black hole (BH) accretion disc systems is known to depend upon both the BH spin (a) and the amount of large-scale magnetic flux threading the BH and disc. Semi-analytical flux-trapping models suggest retrograde BHs should trap much more large-scale magnetic flux near the BH leading to much higher eta than for prograde BHs. We self-consistently determine the amount of large-scale magnetic flux trapped by rapidly spinning (a = -0.9 and 0.9) BHs using global 3D time-dependent non-radiative general relativistic magnetohydrodynamic simulations of thick (h/r ~ 0.3-0.6) discs. We find that BH-trapped flux builds up until it is strong enough to disrupt the inner accretion disc. Contrary to prior flux-trapping models, which do not include the back-reaction of magnetic flux on the disc, our simulations show prograde BHs trap more magnetic flux, leading to about 3 times higher eta than retrograde BHs for |a| = 0.9. Both spin orientations can produce highly efficient jets, eta ~ 100%, with increasing eta for increasing disc thickness. The similarity of eta for prograde and retrograde BHs makes it challenging to infer the sign of BH spin based on jet energetics alone.Comment: 5 pages, 3 figures. Accepted to MNRAS. For associated movies see http://youtu.be/yNZLjsrz0Wo and http://youtu.be/bQE69wti3a

The Lifetime of FRIIs in Groups and Clusters: Implications for Radio-Mode Feedback

We determine the maximum lifetime t_max of 52 FRII radio sources found in 26 central group galaxies from cross correlation of the Berlind SDSS group catalog with the VLA FIRST survey. Mock catalogs of FRII sources were produced to match the selection criteria of FIRST and the redshift distribution of our parent sample, while an analytical model was used to calculate source sizes and luminosities. The maximum lifetime of FRII sources was then determined via a comparison of the observed and model projected length distributions. We estimate the average FRII lifetime is 1.5x10^7 years and the duty cycle is ~8x10^8 years. Degeneracies between t_max and the model parameters: jet power distribution, axial ratio, energy injection index, and ambient density introduce at most a factor of two uncertainty in our lifetime estimate. In addition, we calculate the radio active galactic nuclei (AGN) fraction in central group galaxies as a function of several group and host galaxy properties. The lifetime of radio sources recorded here is consistent with the quasar lifetime, even though these FRIIs have substantially sub-Eddington accretion. These results suggest a fiducial time frame for energy injection from AGN in feedback models. If the morphology of a given extended radio source is set by large-scale environment, while the lifetime is determined by the details of the accretion physics, this FRII lifetime is relevant for all extended radio sources.Comment: 18 pages, 7 figures. Accepted for publication in ApJ. High resolution paper available at http://www.astronomy.ohio-state.edu/~bird/BMK07.pd

Quasi-Periodic Occultation by a Precessing Accretion Disk and Other Variabilities of SMC X-1

We have investigated the variability of the binary X-ray pulsar, SMC X-1, in data from several X-ray observatories. We confirm the ~60-day cyclic variation of the X-ray flux in the long-term monitoring data from the RXTE and CGRO observatories. X-ray light curves and spectra from the ROSAT, Ginga, and ASCA observatories show that the uneclipsed flux varies by as much as a factor of twenty between a high-flux state when 0.71 second pulses are present and a low-flux state when pulses are absent. In contrast, during eclipses when the X-rays consist of radiation scattered from circumsource matter, the fluxes and spectra in the high and low states are approximately the same. These observations prove that the low state of SMC X-1 is not caused by a reduction in the intrinsic luminosity of the source, or a spectral redistribution thereof, but rather by a quasi-periodic blockage of the line of sight, most likely by a precessing tilted accretion disk. In each of two observations in the midst of low states a brief increase in the X-ray flux and reappearance of 0.71 second pulses occurred near orbital phase 0.2. These brief increases result from an opening of the line of sight to the pulsar that may be caused by wobble in the precessing accretion disk. The records of spin up of the neutron star and decay of the binary orbit are extended during 1991-1996 by pulse-timing analysis of ROSAT, ASCA, and RXTE PCA data. The pulse profiles in various energy ranges from 0.1 to >21 keV are well represented as a combination of a pencil beam and a fan beam. Finally, there is a marked difference between the power spectra of random fluctuations in the high-state data from the RXTE PCA below and above 3.4 keV. Deviation from the fitted power law around 0.06 Hz may be QPO.Comment: Accepted to ApJ. 33 pages including 11 figure