Do OB Runaway Stars Have Pulsar Companions?

We have conducted a VLA search for radio pulsars at the positions of 44 nearby OB runaway stars. The observations involved both searching images for point sources of continuum emission and a time series analysis. Our mean flux sensitivity to pulsars slower than 50 ms was 0.2 mJy. No new pulsars were found in the survey. The size of the survey, combined with the high sensitivity of the observations, sets a significant constraint on the probability, $f_p$, of a runaway OB star having an observable pulsar companion. We find $f_p \le 6.5$\% with 95\% confidence, if the general pulsar luminosity function is applicable to OB star pulsar companions. If a pulsar beaming fraction of \onethird\ is assumed, then we estimate that fewer than 20\% of runaway OB stars have neutron star companions, unless pulsed radio emission is frequently obscured by the OB stellar wind. Our result is consistent with the dynamical (or cluster) ejection model for the formation of OB runaways. The supernova ejection model is not ruled out, but is constrained by these observations to allow only a small binary survival fraction, which may be accommodated if neutron stars acquire significant natal kicks. According to Leonard, Hills and Dewey (1994), a 20\% survival fraction corresponds to a 3-d kick velocity of 420 km s$^{-1}$. This value is in close agreement with recent revisions of the pulsar velocity distribution.Comment: Submitted to the Astronomical Journal. 16 pages. Latex uses aaspp4.sty. 3 postscript figures. Address correspondence to Colin Philp ([email protected]). Revision was to replace .ps file with latex fil

Molecular brakes regulating mTORC1 activation in skeletal muscle following synergist ablation

The goal of the current work was to profile positive (mTORC1 activation, autocrine/paracrine growth factors) and negative [AMPK, unfolded protein response (UPR)] pathways that might regulate overload-induced mTORC1 (mTOR complex 1) activation with the hypothesis that a number of negative regulators of mTORC1 will be engaged during a supraphysiological model of hypertrophy. To achieve this, mTORC1- IRS-1/2 signaling, BiP/CHOP/IRE1, and AMPK activation were determined in rat plantaris muscle following synergist ablation (SA). SA resulted in significant increases in muscle mass of 4% per day throughout the 21 days of the experiment. The expression of the insulin-like growth factors (IGF) were high throughout the 21st day of overload. However, IGF signaling was limited, since IRS-1 and -2 were undetectable in the overloaded muscle from day 3 to day 9. The decreases in IRS-1/2 protein were paralleled by increases in GRB10 Ser501/503 and S6K1 Thr389 phosphorylation, two mTORC1 targets that can destabilize IRS proteins. PKB Ser473 phosphorylation was higher from 3– 6 days, and this was associated with increased TSC2 Thr939 phosphorylation. The phosphorylation of TSC2 Thr1345 (an AMPK site) was also elevated, whereas phosphorylation at the other PKB site, Thr1462, was unchanged at 6 days. In agreement with the phosphorylation of Thr1345, SA led to activation of AMPK1 during the initial growth phase, lasting the first 9 days before returning to baseline by day 12. The UPR markers CHOP and BiP were elevated over the first 12 days following ablation, whereas IRE1 levels decreased. These data suggest that during supraphysiological muscle loading at least three potential molecular brakes engage to downregulate mTORC1. m

Lipid Composition of Oil Extracted from Wasted Norway Lobster (Nephrops norvegicus) Heads and Comparison with Oil Extracted from Antarctic Krill (Euphasia superba)

In the UK, the Norway lobster (Nephrops norvegicus) supports its most important shellfish fishery.Nephropsare sold either whole, or as “tails-only” for the scampi trade. In the “tailing” process, the “head” (cephalothorax) is discarded as waste. A smaller crustacean species, the Antarctic krillEuphasia superba, represents an economically valuable industry, as its extractable oil is sold as a human dietary supplement. The aim of this study was to determine the amount and composition of the oil contained in discardedNephropsheads and to compare its composition to the oil extracted from krill. Differences due to Geographical variation and seasonal patterns in the amount and composition of lipid were also noted. Results indicated thatNephropshead waste samples collected from more southern locations in Scotland (Clyde Sea area) contained higher levels of oil when compared to samples collected from northern locations in Iceland. Moreover, seasonal differences within the Clyde Sea area in Scotland were also observed, with oil extracted fromNephropshead waste peaking at around 11.5% during the summer months when larger and more mature females were caught by trawl. At this time of the year, the valuable fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) accounted for around 23% of the total fatty acid content in oil extracted fromNephropshead waste. A seasonal effect on EPA content was found, with higher levels obtained in the summer, while no trend was found in DHA percentages. Finally, oil fromNephropshead waste contained a higher proportion of EPA and DHA than krill oil but these fatty acids were more abundantly linked to the neutral lipids rather to than polar lipids. The characterization of lipid that could be extracted fromNephropshead waste should be seen as a first step for the commercial use of a valuable resource currently wasted. This approach is extremely relevant given the current limited supply of EPA and DHA and changes in the Common Fisheries Policy

Treating and Preventing Influenza in Aged Care Facilities: A Cluster Randomised Controlled Trial

PMCID: PMC3474842This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Nitrous Oxide Enhances Na ϩ /Ca ϩϩ Exchange in the Neuroblastoma Cell Line SK-N-SH 1

ABSTRACT Changes in the concentration of cytosolic free calcium ([Ca ϩ

How to do realistic political theory (and why you might want to)

In recent years, a number of realist thinkers have charged much contemporary political theory with being idealistic and moralistic. While the basic features of the realist counter-movement are reasonably well understood, realism is still considered a critical, primarily negative creed which fails to offer a positive, alternative way of thinking normatively about politics. Aiming to counteract this general perception, in this article I draw on Bernard Williams’s claims about how to construct a politically coherent conception of liberty from the non-political value of freedom. I do this because Williams’s argument provides an illuminating example of the distinctive nature of realist political thinking and its attractions. I argue that Williams’s account of realist political thinking challenges the orthodox moralist claim that normative political arguments must be guided by an ideal ethical theory. I then spell out the repercussions Williams’s claims about the significance of political opposition and non-moralised accounts of motivation have for our understanding of the role and purpose of political theory. I conclude by defending the realist claim that action-guiding political theory should accordingly take certain features of our politics as given, most centrally the reality of political opposition and the passions and experiences that motivate them. On this reading political realism offers a viable way of thinking about political values which cannot be understood in terms of the categories of intellectual separation – ideal/nonideal or fact-insensitive/fact-sensitive – that have marked political theory in recent years

Mead-halls of the Oiscingas: a new Kentish perspective on the Anglo-Saxon great hall complex phenomenon

Widely cited as a metaphor for the emergence of kingship in early medieval England, the great hall complex represents one of the most distinctive and evocative expressions of the Anglo-Saxon settlement record, yet interpretation of these sites remains underdeveloped and heavily weighted towards Yeavering. Inspired by the results of recent excavations at Lyminge, this paper undertakes a detailed comparative interrogation of three great hall complexes in Kent and exploits this new regional perspective to advance understanding of the agency and embodied meanings of these settlements as ‘theatres of power’. Explored through the thematic prisms of place, social memory and monumental hybridity, this examination leads to a new appreciation of the involvement of great hall sites in the genealogical strategies of 7th-century royal dynasties and a fresh perspective on how this remarkable yet short-lived monumental idiom was adapted to harness the symbolic capital of Romanitas

The needle in the haystack - Where to look for more isolated cooling neutron stars

Context: Isolated cooling neutron stars with thermal X-ray emission remain rarely detected objects despite many searches investigating the ROSAT data. Aims: We simulate the population of close-by young cooling neutron stars to explain the current observational results. Given the inhomogeneity of the neutron star distribution on the sky it is particularly interesting to identify promising sky regions with respect to on-going and future searches. Methods: Applying a population synthesis model the inhomogeneity of the progenitor distribution and the inhomogeneity of the X-ray absorbing interstellar medium are considered for the first time. The total number of observable neutron stars is derived with respect to ROSAT count rates. In addition, we present sky maps of neutron star locations and discuss age and distance distributions of the simulated neutron stars. Implications for future searches are discussed. Results: With our advanced model we can successfully explain the observed logN - logS distribution of close-by neutron stars. Cooling neutron stars will be most abundant in the directions of rich OB associations. New candidates are expected to be identified behind the Gould Belt, in particular in the Cygnus-Cepheus region. They are expected to be on average younger and then hotter than the known population of isolated cooling neutron stars. In addition, we propose to use data on runaway stars to search for more radio-quiet cooling neutron stars.Comment: 18 pages, 14 figures; added Erratum after bug in code was discovered, updated results in Appendix, main conclusions do not chang