VLT DETECTION OF A RED SUPERGIANT PROGENITOR OF THE TYPE II-P SUPERNOVA 2008bk

We report the identification of a source coincident with the position of the nearby Type II-P supernova (SN) 2008bk in high-quality optical and near-infrared preexplosion images from the ESO Very Large Telescope (VLT). The SN position in the optical and near-infrared preexplosion images is identified to within about +/- 70 and +/- 40 mas, respectively, using postexplosion-band images obtained with the NAOS CONICA adaptive optics system K-s on the VLT. The preexplosion source detected in four different bands is precisely coincident with SN 2008bk and is consistent with being dominated by a single point source. We determine the nature of the point source using the STARS stellar evolutionary models and find that its colors and luminosity are consistent with the source being a red supergiant progenitor of SN 2008bk with an initial mass of 8.5 +/- 1.0 M-circle dot.

Classical novae from the POINT-AGAPE microlensing survey of M31 - II. Rate and statistical characteristics of the nova population

The POINT-AGAPE (Pixel-lensing Observations with the Isaac Newton Telescope-Andromeda Galaxy Amplified Pixels Experiment) survey is an optical search for gravitational microlensing events towards the Andromeda galaxy (M31). As well as microlensing, the survey is sensitive to many different classes of variable stars and transients. In our first paper of this series, we reported the detection of 20 classical novae (CNe) observed in Sloan r' and i' passbands.

Theory of pixel lensing toward M31. II. The velocity anisotropy and flattening of the MACHO distribution

The POINT-AGAPE collaboration is currently searching for massive compact halo objects (MACHOs) toward the Andromeda galaxy (M31). The survey aims to exploit the high inclination of the M31 disk, which causes an asymmetry in the spatial distribution of M31 MACHOs. Here, we investigate the effects of halo velocity anisotropy and flattening on the asymmetry signal using simple halo models. For a spherically symmetric and isotropic halo, we find that the underlying pixel lensing rate in far-disk M31 MACHOs is more than 5 times the rate of near-disk events. We find that the asymmetry is further increased by about 30% if the MACHOs occupy radial orbits rather than tangential orbits, but it is substantially reduced if the MACHOs lie in a flattened halo. However, even for halos with a minor- to major-axis ratio of q = 0.3, the number of M31 MACHOs in the far side outnumber those in the near side by a factor of similar to2. There is also a distance asymmetry, in that the events on the far side are typically farther from the major axis. We show that, if this positional information is exploited in addition to number counts, then the number of candidate events required to confirm asymmetry for a range of flattened and anisotropic halo models is achievable, even with significant contamination by variable stars and foreground microlensing events. For pixel lensing surveys that probe a representative portion of the M31 disk, a sample of around 50 candidates is likely to be sufficient to detect asymmetry within spherical halos, even if half the sample is contaminated, or to detect asymmetry in halos as flat as q = 0.3, provided less than a third of the sample comprises contaminants. We also argue that, provided its mass-to-light ratio is less than 100, the recently observed stellar stream around M31 is not problematic for the detection of asymmetry.

An upper mass limit for the progenitor of the Type II-P supernova SN 1999gi

Masses and progenitor evolutionary states of Type II supernovae remain almost unconstrained by direct observations. Only one robust observation of a progenitor (SN 1987A) and one plausible observation (SN 1993J) are available. Neither matched theoretical predictions, and in this Letter we report limits on a third progenitor (SN 1999gi). The Hubble Space Telescope (HST) has imaged the site of the Type II-P supernova SN 1999gi with the Wide Field Planetary Camera 2 (WFPC2) in two filters (F606W and F300W) prior to explosion. The distance to the host galaxy (NGC 3184) of 7.9 Mpc means that the most luminous, massive stars are resolved as single objects in the archive images. The supernova occurred in a resolved, young OB association 2.3 kpc from the center of NGC 3184 with an association age of about 4 Myr. Follow-up images of SN 1999gi with WFPC2 taken 14 months after discovery determine the precise position of the supernova on the preexplosion frames. An upper limit of the absolute magnitude of the progenitor is estimated (M-v greater than or equal to -5.1). By comparison with stellar evolutionary tracks, this can be interpreted as a stellar mass, and we determine an upper mass limit of 9(-2)(+3) M.. We discuss the possibility of determining the masses or mass limits for numerous nearby core-collapse supernovae using the HST archive enhanced by our current SNAP program.

Engaging with the European Union? Exploring the Europeanization of the British National Party

Hostility towards the process of European integration is generally considered to constitute one of the hallmarks of the far right ‘family’ in Europe. This article acknowledges such opposition but it also recognises that the rhetoric is often at odds with actual policy activities and aspirations. Not only have far right parties long advocated greater European inter-party co-operation but they are now actively pursuing engagement with the European Union, especially the European Parliament, as a means of advancing their own strategic interests and boosting their finances. This article focuses on one far right party, namely the British National Party (BNP) and examines the party's approach towards the EU, its activities within the EP and its efforts to boost pan European cooperation through the new Alliance of European National Movements (AENM). It argues that the party's engagement with the European Union may have allowed the BNP to take advantage of new political opportunity structures but in turn, opened it up to Europeanization and made it increasingly dependent on the EU.

Burkholderia cenocepacia Type VI Secretion System Mediates Escape of Type II Secreted Proteins into the Cytoplasm of Infected Macrophages

Burkholderia cenocepacia is an opportunistic pathogen that survives intracellularly in macrophages and causes serious respiratory infections in patients with cystic fibrosis. We have previously shown that bacterial survival occurs in bacteria-containing membrane vacuoles (BcCVs) resembling arrested autophagosomes. Intracellular bacteria stimulate IL-1ß secretion in a caspase-1-dependent manner and induce dramatic changes to the actin cytoskeleton and the assembly of the NADPH oxidase complex onto the BcCV membrane. A Type 6 secretion system (T6SS) is required for these phenotypes but surprisingly it is not required for the maturation arrest of the BcCV. Here, we show that macrophages infected with B. cenocepacia employ the NLRP3 inflammasome to induce IL-1ß secretion and pyroptosis. Moreover, IL-1ß secretion by B. cenocepacia-infected macrophages is suppressed in deletion mutants unable to produce functional Type VI, Type IV, and Type 2 secretion systems (SS). We provide evidence that the T6SS mediates the disruption of the BcCV membrane, which allows the escape of proteins secreted by the T2SS into the macrophage cytoplasm. This was demonstrated by the activity of fusion derivatives of the T2SS-secreted metalloproteases ZmpA and ZmpB with adenylcyclase. Supporting this notion, ZmpA and ZmpB are required for efficient IL-1ß secretion in a T6SS dependent manner. ZmpA and ZmpB are also required for the maturation arrest of the BcCVs and bacterial intra-macrophage survival in a T6SS-independent fashion. Our results uncover a novel mechanism for inflammasome activation that involves cooperation between two bacterial secretory pathways, and an unanticipated role for T2SS-secreted proteins in intracellular bacterial survival.

Urotensin II in the central nervous system of the frog Rana ridibunda: Immunohistochemical localization and biochemical characterization

Urotensin II (UII) is traditionally regarded as a product of the neurosecretory cells in the caudal portion of the spinal cord of jawed fishes. A peptide related to UII has been recently isolated from the frog brain, thereby providing the first evidence that UII is also present in the central nervous system of a tetrapod. In the present study, we have investigated the distribution of UII-immunoreactive elements in the brain and spinal cord of the frog Rana ridibunda by immunofluorescence using an antiserum directed against the conserved cyclic region of the peptide. Two distinct populations of UII-immunoreactive perikarya were visualized. The first group of positive neurons was found in the nucleus hypoglossus of the medulla oblongata, which controls two striated muscles of the tongue. The second population of immunoreactive cell bodies was represented by a subset of motoneurons that were particularly abundant in the caudal region of the cord (34% of the motoneuron population). The telencephalon, diencephalon, mesencephalon, and metencephalon were totally devoid of UII-containing cell bodies but displayed dense networks of UII-immunoreactive fibers, notably in the thalamus, the tectum, the tegmentum, and the granular layer of the cerebellum. In addition, a dense bundle of long varicose processes projecting rostrocaudally was observed coursing along the ventral surface of the brain from the midtelencephalon to the medulla oblongata. Reversed-phase high-performance liquid chromatography analysis of frog brain, medulla oblongata, and spinal cord extracts revealed that, in all three regions, UII-immunoreactive material eluted as a single peak which exhibited the same retention time as synthetic frog UII. Taken together, these data indicate that UII, in addition to its neuroendocrine functions in fish, is a potential regulatory peptide in the central nervous system of amphibians. (C) 1996 Wiley-Liss, Inc.