Infrared spectrum of an extremely cool white-dwarf star

White dwarfs are the remnant cores of stars that initially had masses of less than 8 solar masses. They cool gradually over billions of years, and have been suggested(1,2) to make up much of the 'dark matter' in the halo of the Milky way. But extremely cool white dwarfs have proved difficult to detect, owing to both their faintness and their anticipated similarity in colour to other classes of dwarf stars. Recent improved models(3-5) indicate that white dwarfs are much more blue than previously supposed, suggesting that the earlier searches may have been looking for the wrong kinds of objects. Here we report an infrared spectrum of an extremely cool white dwarf that is consistent with the new models. We determine the star's temperature to be 3,500 +/- 200 K, making it the coolest known white dwarf. The kinematics of this star indicate that it is in the halo of the Milky Way, and the density of such objects implied by the serendipitous discovery of this star is consistent with white dwarfs dominating the dark matter in the halo.

Dense spectrum of resonances and particle capture in a near-black-hole metric

We show that a quantum scalar particle in the gravitational field of a massive body of radius R which slightly exceeds the Schwarzschild radius rs, possesses a dense spectrum of narrow resonances. Their lifetimes and density tend to infinity in the limit R?rs. We determine the cross section of the particle capture into these resonances and show that it is equal to the absorption cross section for a Schwarzschild black hole. Thus, a nonsingular static metric acquires black-hole properties before the actual formation of a black hole.

Microwave Irradiation for the Facile Synthesis of Transition-Metal Nanoparticles (NPs) in Ionic Liquids (ILs) from Metal-Carbonyl Precursors and Ru-, Rh-, and Ir-NP/IL Dispersions as Biphasic Liquid-Liquid Hydrogenation Nanocatalysts for Cyclohexene

Stable chromium, molybdenum, tungsten, manganese, rhenium, ruthenium, osmium, cobalt, rhodium, and iridium metal nanoparticles (MNPs) have been reproducibly obtained by facile, rapid (3 min), and energysaving 10 W microwave irradiation (MWI) under an argon atmosphere from their metal–carbonyl precursors [Mx(CO)y] in the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]). This MWI synthesis is compared to UV-photolytic (1000 W, 15 min) or conventional thermal decomposition (180–2508C, 6–12 h) of [Mx(CO)y] in ILs. The MWIobtained nanoparticles have a very small (<5 nm) and uniform size and are prepared without any additional stabilizers or capping molecules as long-term stable M-NP/IL dispersions (characterization by transmission electron microscopy (TEM), transmission electron diffraction (TED), and dynamic light scattering (DLS)). The ruthenium, rhodium, or iridium nanoparticle/IL dispersions are highly active
and easily recyclable catalysts for the biphasic liquid–liquid hydrogenation of cyclohexene to cyclohexane with activities of up to 522 (mol product)(mol Ru)1h1 and 884 (mol product)(molRh)1h1 and give almost quantitative conversion within 2 h at 10 bar H2 and 908C. Catalyst poisoning experiments with CS2 (0.05 equiv per Ru) suggest a heterogeneous surface catalysis of RuNPs.

Evidence for relativistic features in the X-ray spectrum of Mrk 335

We present an analysis of hard X-ray features in the spectrum of the bright Sy 1 galaxy Mrk 335 observed by the XMM-Newton satellite. Our analysis confirms the presence of a broad, ionized Fe Ka emission line in the spectrum, first found by Gondoin et al. The broad line can be modelled successfully by relativistic accretion disc reflection models. This interpretation is unusually robust in the case of Mrk 335 because of the lack of any ionized ('warm') absorber and the absence a clear narrow core to the line. Partial covering by neutral gas cannot, however, be ruled out statistically as the origin of the broad residuals. Regardless of the underlying continuum we report, for the first time in this source, the detection of a narrow absorption feature at the rest frame energy of ~5.9 keV. If the feature is identified with a resonance absorption line of iron in a highly ionized medium, the redshift of the line corresponds to an inflow velocity of ~0.11-0.15c. We present a simple model for the inflow, accounting approximately for relativistic and radiation pressure effects, and use Monte Carlo methods to compute synthetic spectra for qualitative comparison with the data. This modelling shows that the absorption feature can plausibly be reproduced by infalling gas providing that the feature is identified with Fe xxvi. We require the inflowing gas to extend over a limited range of radii at a few tens of r to match the observed feature. The mass accretion rate in the flow corresponds to 60 per cent of the Eddington limit, in remarkable agreement with the observed rate. The narrowness of the absorption line tends to argue against a purely gravitational origin for the redshift of the line, but given the current data quality we stress that such an interpretation cannot be ruled out. © 2006 The Authors.

Mutational spectrum of the ZEB1 gene in corneal dystrophies supports a genotype-phenotype correlation

Mutations in ZEB1 have been reported in posterior polymorphous corneal dystrophy (PPCD3; MIM #609141) and Fuchs' endothelial corneal dystrophy (FECD6; MIM #613270). Although PPCD and keratoconus are clinically and pathologically distinct, PPCD has been associated with keratoconus, suggesting a common genetic basis. The purpose of our study was to perform mutational screening of the ZEB1 gene in patients affected with keratoconus or PPCD.

“I miss being spoon-fed”. A comparison of transition from school to university education from the perspective of undergraduate pharmacy students

Background: The transition from school to university can be challenging and there is increasing concern among academics that students are inadequately prepared for entry to university courses.Aims: To investigate students’ views on transition from school to university education.Method: A focus group was conducted with first-year students and analysed using thematic analysis. Students were invited to participate in an electronic questionnaire; responses were analysed via SPSS for Windows. The Mann– Whitney U test was utilised with p<0.05 set as significant.Results: A response rate of 60% (88/147) was obtained for the questionnaire. Differences included staff-student interactions, learning methods, examination preparation and feedback provision. Many (85%) agreed that the main emphasis in school was on examination preparation; 29.6% considered this to be the case at university (z=-8.315; p<0.05). Most students (95.4%) considered the feedback they received at school helped improve performance; this decreased to 50% when asked about feedback at university (z=-8.326; p<0.05).Conclusion: Students appear to be insufficiently prepared for the demands of higher education. They desire various aspects of their university educational experience to be more akin to that of school, including: a greater level of individual attention, increased access to teaching staff, and further clarification and transparency about the standard required to pass exams. Further work can now be done by academic staff to aid the transition and improve the learning experience.

Resonantly Enhanced Multi-Photon Ionization Spectrum of the Neutral Green Fluorescent Protein Chromophore

The photophysics of the green fluorescent protein is governed by the electronic structure of the chromophore at the heart of its β-barrel protein structure. We present the first two-color, resonance-enhanced, multiphoton ionization spectrum of the isolated neutral chromophore in vacuo with supporting electronic structure calculations. We find the absorption maximum to be 3.65 ± 0.05 eV (340 ± 5 nm), which is blue-shifted by 0.5 eV (55 nm) from the absorption maximum of the protein in its neutral form. Our results show that interactions between the chromophore and the protein have a significant influence on the electronic structure of the neutral chromophore during photoabsorption and provide a benchmark for the rational design of novel chromophores as fluorescent markers or photomanipulators.

A realist literature review of transition to adult services by young people with life-limiting conditions in ireland.

Background As a result of improvements in care and treatment more young people with life-limiting conditions are now living beyond childhood, meaning they must make the transition from children's to adult services. The loss of long-standing relationships with providers of children's services combines with poor co-ordination of services to make this a daunting prospect for young people and their families. However, there is little evidence on transition services for young people with life limiting conditions, with few models of good practice in the literature.


Aims The purpose of this review was to determine the factors that promote or hinder the transition to adult services for young adults with life limiting conditions, and identify gaps to be addressed.


Methods A comprehensive search of the literature was undertaken using key terms, of the following databases; MEDLINE and the Cochrane Database of Systematic Reviews. 314 articles were sourced and inclusion and exclusion criteria were applied to highlight the most relevant literature.


Results Studies were reviewed using a realist review approach and three themes emerged from the literature. Barriers and facilitators to the transition process were identified associated with: 1. The patient 2. Parents/carers 3. The organisation.


Conclusion It is unclear from the literature what the specific factors are that promote or hinder the transition process for young adults with life limiting conditions who go through the transition from children's to adult services, therefore, research is required to identify the factors that promote and hinder the transition process in Ireland. This research is currently being carried out by the author as part of Doctoral studies. The three year full time Doctoral study commenced in January 2013 and is funded by the All Ireland Institute of Hospice and Palliative Care.