Characterisation of species and diversity of Anopheles gambiae Keele Colony

Anopheles gambiae sensu stricto was recently reclassified as two species, An. coluzzii and An. gambiae s.s., in wild-caught mosquitoes, on the basis of the molecular form, denoted M or S, of a marker on the X chromosome. The An. gambiae Keele line is an outbred laboratory colony strain that was developed around 12 years ago by crosses between mosquitoes from 4 existing An. gambiae colonies. Laboratory colonies of mosquitoes often have limited genetic diversity because of small starting populations (founder effect) and subsequent fluctuations in colony size. Here we describe the characterisation of the chromosomal form(s) present in the Keele line, and investigate the diversity present in the colony using microsatellite markers on chromosome 3. We also characterise the large 2La inversion on chromosome 2. The results indicate that only the M-form of the chromosome X marker is present in the Keele colony, which was unexpected given that 3 of the 4 parent colonies were probably S-form. Levels of diversity were relatively high, as indicated by a mean number of microsatellite alleles of 6.25 across 4 microsatellites, in at least 25 mosquitoes. Both karyotypes of the inversion on chromosome 2 (2La/2L+a) were found to be present at approximately equal proportions. The Keele colony has a mixed M- and S-form origin, and in common with the PEST strain, we propose continuing to denote it as an An. gambiae s.s. line

FUSE Observations of the Dwarf Novae UU Aql, BV Cen, and CH UMa in Quiescence

We report on FUSE spectra of three U Gem-type, long period, dwarf novae, UU Aql, BV Cen and CH UMa taken during their quiescence intervals. We discuss the line identifications in their spectra and attempt to characterize the source(s) of their FUV flux distribution. Archival IUE spectrum of CH UMa and BV Cen in quiescence were identified as having a matching flux level with the FUSE spectra and these were combined with each FUSE spectrum to broaden the wavelength coverage and further constrain model fits. Multi-component synthetic spectral fits from our model grids, consisting of single temperature white dwarfs, two-temperature white dwarfs, accretion disks and white dwarfs plus accretion disks, were applied to the FUSE spectra alone and to the combined FUSE + IUE spectra. We present the results of our model analyses and their implications.Comment: accepted in AJ, 26 pages, 6 tables, 8 figures (5 color, 3 b/w

Detection of Coronal Mass Ejections in V471 Tauri with the Hubble Space Telescope

V471 Tauri, an eclipsing system consisting of a hot DA white dwarf (WD) and a dK2 companion in a 12.5-hour orbit, is the prototype of the pre-cataclysmic binaries. The late-type component is magnetically active, due to its being constrained to rotate synchronously with the short orbital period. During a program of UV spectroscopy of V471 Tau, carried out with the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope, we serendipitously detected two episodes in which transient absorptions in the Si III 1206 A resonance line appeared suddenly, on a timescale of <2 min. The observations were taken in a narrow spectral region around Ly-alpha, and were all obtained near the two quadratures of the binary orbit, i.e., at maximum projected separation (~3.3 Rsun) of the WD and K star. We suggest that these transient features arise when coronal mass ejections (CME's) from the K2 dwarf pass across the line of sight to the WD. Estimates of the velocities, densities, and masses of the events in V471 Tau are generally consistent with the properties of solar CME's. Given our detection of 2 events during 6.8 hr of GHRS observing, along with a consideration of the restricted range of latitudes and longitudes on the K star's surface that can give rise to trajectories passing in front of the WD as seen from Earth, we estimate that the active V471 Tau dK star emits some 100-500 CME's per day, as compared to 1-3 per day for the Sun. The K dwarf's mass-loss rate associated with CME's is at least (5-25) x 10^{-14} Msun/yr, but it may well be orders of magnitude higher if most of the silicon is in ionization states other than Si III.Comment: 24 pages AASTeX, 4 figures. Accepted by Astrophysical Journa

On high proper motion white dwarfs from photographic surveys

The interpretation of high proper motion white dwarfs detected by Oppenheimer et al (2001) was the start of a lively controversy. While the discoverers identify a large fraction of their findings as dark halo members, others interpret the same sample as essentially made of disc and/or thick disc stars. We use the comprehensive description of Galactic stellar populations provided by the "Besancon" model to produce a realistic simulation of Oppenheimer et al. data, including all observational selections and calibration biases. The conclusion is unambiguous: Thick disc white dwarfs resulting from ordinary hypotheses on the local density and kinematics are sufficient to explain the observed objects, there is no need for halo white dwarfs. This conclusion is robust to reasonable changes in model ingredients. The main cause of the misinterpretation seems to be that the velocity distribution of a proper motion selected star sample is severely biased in favour of high velocities. This has been neglected in previous analyses. Obviously this does not prove that no such objects like halo white dwarfs can exist, but Oppenheimer et al. observations drive their possible contribution in the dark matter halo down to an extremely low fraction.Comment: 4 pages, 1 figure, A&A Letters, accepte

Rocky Planetesimals as the Origin of Metals in DZ Stars

{Abridged}. An analysis of the calcium and hydrogen abundances, Galactic positions and kinematics of 146 DZ stars from the Sloan Digital Sky Survey demonstrates that interaction with the interstellar medium cannot account for their externally polluted atmospheres. The calcium-to-hydrogen ratios for the 37 DZA stars are dominated by super-solar values, as are the lower limits for the remaining 109 DZ stars. All together their metal-contaminated convective envelopes contain 10^{20+-2} g of calcium, commensurate with the masses of calcium inferred for large asteroids. It is probable that these stars are contaminated by circumstellar matter; the rocky remains of terrestrial planetary systems. In this picture, two predictions emerge: 1) at least 3.5% of all main sequence A- and F-type stars build terrestrial planets; and 2) the DZA stars are externally polluted by both metals and hydrogen, and hence constrain the frequency and mass of water-rich, extrasolar planetesimals.Comment: Accepted to MNRA

Composite Accretion Disk and White Dwarf Photosphere Analyses of the FUSE and HST Observations of EY Cygni

We explore the origin of FUSE and HST STIS far UV spectra of the dwarf nova, EY Cyg, during its quiescence using \emph{combined} high gravity photosphere and accretion disk models as well as model accretion belts. The best-fitting single temperature white dwarf model to the FUSE plus HST STIS spectrum of EY Cygni has T$_{eff} = 24,000$K, log $g = 9.0$, with an Si abundance of 0.1 x solar and C abundance of 0.2 x solar but the distance is only 301 pc. The best-fitting composite model consists of white dwarf with T$_{eff} = 22,000$K, log $g = 9$, plus an accretion belt with T$_{belt} = 36,000$K covering 27% of the white dwarf surface with V$_{belt} sin i = 2000$ km/s. The accretion belt contributes 63% of the FUV light and the cooler white dwarf latitudes contribute 37%. This fit yields a distance of 351 pc which is within 100 pc of our adopted distance of 450 pc. EY Cyg has very weak C {\sc iv} emission and very strong N {\sc v} emission, which is atypical of the majority of dwarf novae in quiescence. We also conducted a morphological study of the surroundings of EY Cyg using direct imaging in narrow nebular filters from ground-based telescopes. We report the possible detection of nebular material^M associated with EY Cygni. Possible origins of the apparently large N {\scv}/C {\sc iv} emission ratio are discussed in the context of nova explosions, contamination of the secondary star and accretion of nova abundance-enriched matter back to the white dwarf via the accretion disk or as a descendant of a precursor binary that survived thermal timescale mass transfer. The scenario involving pollution of the secondary by past novae may be supported by the possible presence of a nova remnant-like nebula around EY Cyg.Comment: To appear in AJ, Oct. 2004. 5 figures, including 2 color ones (2D pictures

A trophic model of the benthopelagic fauna distributed in the Santa Maria di Leuca cold-water coral province (Mediterranean Sea)

The benthopelagic fauna distributed in and around the Santa Maria di Leuca (SML) cold-water coral (CWC) province (Northern Ionian Sea–Central Mediterranean Sea) was analyzed through the development of a mass-balanced ecosystem model. A total of nine balanced simulations were provided taking into account the biomass data collected during several experimental bottom trawl surveys carried out from 2005 to 2010 in a depth range between 101 and 541 m. A total of 100 species were included in the analysis corresponding to 15 cephalopods, 25 crustaceans, 7 chondrichthyes and 54 osteichthyes. Simulations were developed maintaining the species-level detail. The total system throughput estimated in the SML CWC province trophic web resulted mainly due to consumption and about 80% of it was maintained by species with trophic level between 2 and 4. Results highlighted important features in terms of the structure and functioning of the system, such as the high level of activity maintained by intermediate trophic levels and the important role of top-down control in the faunal assemblage due to both vertebrate and invertebrate species

Formulation of hydrophobic peptides for skin delivery via coated microneedles

Microneedles (MNs) have been investigated as a minimally-invasive delivery technology for a range of active pharmaceutical ingredients (APIs). Various formulations and methods for coating the surface of MNs with therapeutics have been proposed and exemplified, predominantly for hydrophilic drugs and particulates. The development of effective MN delivery formulations for hydrophobic drugs is more challenging with dosing restrictions and the use of organic solvents impacting on both the bioactivity and the kinetics of drug release. In this study we propose a novel formulation that is suitable for MN coating of hydrophobic auto-antigen peptides currently being investigated for antigen specific immunotherapy (ASI) of type 1 diabetes. The formulation, comprising three co-solvents (water, 2-methyl-2-butanol and acetic acid) and polyvinylalcohol 2000 (PVA2000) can dissolve both hydrophilic and hydrophobic peptide auto-antigens at relatively high, and clinically relevant, concentrations (25 mg/ml or 12.5 mg/ml). The drug:excipient ratio is restricted to 10:1 w/w to maximise dose whilst ensuring that the dry-coated payload does not significantly impact on MN skin penetration performance. The coating formulation and process does not adversely affect the biological activity of the peptide. The delivery efficiency of the coated peptide into skin is influenced by a number of parameters. Electropolishing the metal MN surface increases delivery efficiency from 2.0 ± 1.0% to 59.9 ± 6.7%. An increased mass of peptide formulation per needle, from 0.37 μg to 2 μg peptide dose, resulted in a thicker coating and a 20% reduction in the efficiency of skin delivery. Other important performance parameters for coated MNs include the role of excipients in assisting dissolution from the MNs, the intrinsic hydrophobicity of the peptide and the species of skin model used in laboratory studies. This study therefore both exemplifies the potential of a novel formulation for coating hydrophobic and hydrophilic peptides onto MN devices and provides new insight into the factors that influence delivery efficiency from coated MNs. Importantly, the results provide guidance for identifying critical attributes of the formulation, coating process and delivery device, that confer reproducible and effective delivery from coated MNs, and thus contribute to the requirements of the regulators appraising these devices

Far Ultraviolet Observations of the Dwarf Nova VW Hyi in Quiescence

We present a 904-1183 A spectrum of the dwarf nova VW Hydri taken with the Far Ultraviolet Spectroscopic Explorer during quiescence, eleven days after a normal outburst, when the underlying white dwarf accreter is clearly exposed in the far ultraviolet. However, model fitting show that a uniform temperature white dwarf does not reproduce the overall spectrum, especially at the shortest wavelengths. A better approximation to the spectrum is obtained with a model consisting of a white dwarf and a rapidly rotating ``accretion belt''. The white dwarf component accounts for 83% of the total flux, has a temperature of 23,000K, a v sin i = 400 km/s, and a low carbon abundance. The best-fit accretion belt component accounts for 17% of the total flux, has a temperature of about 48,000-50,000K, and a rotation rate Vrot sin i around 3,000-4,000 km/s. The requirement of two components in the modeling of the spectrum of VW Hyi in quiescence helps to resolve some of the differences in interpretation of ultraviolet spectra of VW Hyi in quiescence. However, the physical existence of a second component (and its exact nature) in VW Hyi itself is still relatively uncertain, given the lack of better models for spectra of the inner disk in a quiescent dwarf nova.Comment: 6 figures, 10 printed page in the journal, to appear in APJ, 1 Sept. 2004 issue, vol. 61

Draft Genome Sequences of Salinivibrio proteolyticus, Salinivibrio sharmensis, Salinivibrio siamensis, Salinivibrio costicola subsp. alcaliphilus, Salinivibrio costicola subsp. vallismortis, and 29 New Isolates Belonging to the Genus Salinivibrio

The draft genome sequences of 5 type strains of species of the halophilic genus Salinivibrio and 29 new isolates from different hypersaline habitats belonging to the genus Salinivibrio have been determined. The genomes have 3,123,148 to 3,641,359 bp, a G+C content of 49.2 to 50.9%, and 2,898 to 3,404 open reading frames (ORFs).España, Ministerio de Ciencia e Innovación CGL2013-46941-