Scintigraphic assessment of sympathetic innervation after transmural versus nontransmural myocardial infarction

To evaluate the feasibility of detecting denervated myocardium in the infarcted canine heart, the distribution of sympathetic nerve endings using 1–123 metaiodobenzylguanidine (MIBG) was compared with the distribution of perfusion using thallium-201, with the aid of color-coded computer functional map in 16 dogs. Twelve dogs underwent myocardial infarction by injection of vinyl latex into the left anterior descending coronary artery (transmural myocardial infarction, n = 6), or ligation of the left anterior descending coronary artery (nontransmural myocardial infarction, n = 6). Four dogs served as sham-operated controls. Image patterns were compared with tissue norepinephrine content and with histofluorescence microscopic findings in biopsy specimens.Hearts with transmural infarction showed zones of absent MIBG and thallium, indicating scar. Adjacent and distal regions showed reduced MIBG but normal thallium uptake, indicating viable but denervated myocardium. Denervation distal to infarction was confirmed by reduced norepinephrine content and absence of nerve fluorescence. Nontransmural myocardial infarction showed zones of wall thinning with decreased thallium uptake and a greater reduction or absence of MIBG localized to the region of the infarct, with minimal extension of denervation beyond the infarct. Norepinephrine content was significantly reduced in the infarct zone, and nerve fluorescence was absent.These findings suggest that 1) MIBG imaging can detect viable and perfused but denervated myocardium after infarction; and 2) as opposed to the distal denervation produced by transmural infarction, nontransmural infarction may lead to regional ischemic damage of sympathetic nerves, but may spare subepicardial nerve trunks that course through the region of infarction to provide a source of innervation to distal areas of myocardium

Surrounded by sound: The impact of tinnitus on musicians

AIM: To investigate the impact of tinnitus on professional musicians in the UK. BACKGROUND: Tinnitus is the experience of sound when an external source is absent, primarily associated with the ageing process, hearing loss, and noise exposure. Amongst populations exposed to industrial noise, noise exposure and noise-induced hearing loss (NIHL) have been found to be the factors most associated with tinnitus. The risk of NIHL amongst professional musicians is greater than that amongst the general population, meaning they may be at increased risk of tinnitus. METHODS: Seventy-four professional musicians completed an online survey involving closed and open-ended questions, and completed the Tinnitus fuctional Index (TFI) questionnaire. Descriptive statistics and thematic analysis of open-ended qualitative responses were used to analyse the data. RESULTS: Three themes were generated from the analysis of the responses to the open-ended questions. These themes were: (1) the impact of tinnitus on the lives of professional musicians, (2) professional musician experience of tinnitus services, support, and hearing health and safety, and (3) the support professional musicians want. The mean global TFI score for professional musicians was 39.05, interpreted as tinnitus being a moderate problem. Comparisons with general population data revealed lower TFI scores for the TFI subscales of ‘sense of control’ and ‘intrusiveness’ for professional musicians and higher for auditory difficulties associated with tinnitus amongst professional musicians. CONCLUSION: Tinnitus can negatively impact on professional musicians’ lives. There is a need for bespoke self-help groups, awareness raising, and education to prevent tinnitus and promote hearing health among musicians

Impact of the Great Recession on Unemployed Youth and NEET Individuals. ESRI Research Bulletin 2015/1/3

The impact that the Great Recession had on Ireland’s labour market is well documented, with the country’s unemployment rate increasing from 4.6 per cent in 2006 to 15 per cent in 2012. Young people were particularly hard hit by the downturn: their unemployment rate increased from 9.9 per cent to 33 per cent over the same time period. With this, the proportion of unemployed youths with no formal education increased over the recessionary period, as did the percentage that were long-term unemployed and those not in employment, education or training (NEET). While policymakers are aware of the unemployment rate of young people, little is known about this group’s profile or their labour market transitions, specifically into employment, pre and post the Great Recession. The same is true for NEET individuals. Given the importance of this information in the design of effective activation measures to assist unemployed youths and NEET individuals, ESRI researchers were involved in a number of studies examining unemployed and NEET youths: some of this work was undertaken in collaboration with the OECD. The results from this research are summarised in this Research Bulletin

Structural disorder and magnetism in the spin-gapless semiconductor CoFeCrAl

Disordered CoFeCrAl and CoFeCrSi0.5Al0.5 alloys have been investigated experimentally and by first-principle calculations. The melt-spun and annealed samples all exhibit Heusler-type superlattice peaks, but the peak intensities indicate a substantial degree of B2-type chemical disorder. Si substitution reduces the degree of this disorder. Our theoretical analysis also considers several types of antisite disorder (Fe-Co, Fe-Cr, Co-Cr) in Y-ordered CoFeCrAl and partial substitution of Si for Al. The substitution transforms the spin-gapless semiconductor CoFeCrAl into a halfmetallic ferrimagnet and increases the half-metallic band gap by 0.12 eV. Compared CoFeCrAl, the moment of CoFeCrSi0.5Al0.5 is predicted to increase from 2.01 μB to 2.50 μB per formula unit, in good agreement with experiment

The Dipion Mass Spectrum In e+e- Annihilation and tau Decay: A Dynamical (rho0, omega, phi) Mixing Approach

We readdress the problem of finding a simultaneous description of the pion form factor data in e+e- annihilations and in tau decays. For this purpose, we work in the framework of the Hidden Local Symmetry (HLS) Lagrangian and modify the vector meson mass term by including the pion and kaon loop contributions. This leads us to define the physical rho, omega and phi fields as linear combinations of their ideal partners, with coefficients being meromorphic functions of s, the square of the 4--momentum flowing into the vector meson lines. This allows us to define a dynamical, i.e. s-dependent, vector meson mixing scheme. The model is overconstrained by extending the framework in order to include the description of all meson radiative (V P gamma and P gamma gamma couplings) and leptonic (Ve+e- couplings) decays and also the isospin breaking (omega/ phi --> pi+ pi-) decay modes. The model provides a simultaneous, consistent and good description of the e+e- and tau dipion spectra. The expression for pion form factor in the latter case is derived from those in the former case by switching off the isospin breaking effects specific to e+e- and switching on those for tau decays. Besides, the model also provides a good account of all decay modes of the form V P gamma, Pgamma gamma as well as the isospin breaking decay modes. It leads us to propose new reference values for the rho^0 --> e+ e- and omega --> pi+ pi- partial widths which are part of our description of the pion form factor. Other topics (phi --> K anti K, the rho meson mass and width parameters) are briefly discussed. Therefore, we confirm the 3.3 sigma discrepancy between the theoretical estimate of a_mu based on e+e- and its direct BNL measurement.Comment: 71 pages, 8 figures. Accepted by EPJ C. Version 3: correct minor typos, minor changes spread out into the text. Extension of Sections 12.2 and 12.3.5 and introduction of the new Appendix

The spatial distribution and origin of the FUV excess in early-type galaxies

We present surface photometry of a sample of 52 galaxies from the GALEX and 2MASS data archives, these include 32 normal elliptical galaxies, 10 ellipticals with weak Liner or other nuclear activity, and 10 star forming ellipticals or early-type spirals. We examine the spatial distribution of the Far Ultra-Violet excess in these galaxies, and its correlation with dynamical and stellar population properties of the galaxies. From aperture photometry we find that all galaxies except for recent major remnants and galaxies with ongoing star formation show a positive gradient in the (FUV-NUV) colour determined from the GALEX images. The logarithmic gradient does not correlate with any stellar population parameter, but it does correlate with the central velocity dispersion. The strength of the excess on the other hand, correlates with both [alpha/Fe] and [Z/H], but more strongly with the former. We derive models of the underlying stellar population from the 2MASS H-band images, and the residual of the image from this model reveals a map of the centrally concentrated FUV excess. We examine a possible hypothesis for generating the FUV excess and the radial gradient in its strength, involving a helium abundance gradient set up early in the formation process of the galaxies. If this hypothesis is correct, the persistence of the gradients to the present day places a strong limit on the importance of dry mergers in the formation of ellipticals.Comment: 36 pages, accepted for publication in MNRAS. Appendices will appear in online journal only. This version has reduced resolution for the figure in Appendix B to comply with arXiv size limit

The Angular Correlation Function of Galaxies from Early SDSS Data

The Sloan Digital Sky Survey is one of the first multicolor photometric and spectroscopic surveys designed to measure the statistical properties of galaxies within the local Universe. In this Letter we present some of the initial results on the angular 2-point correlation function measured from the early SDSS galaxy data. The form of the correlation function, over the magnitude interval 18<r*<22, is shown to be consistent with results from existing wide-field, photographic-based surveys and narrower CCD galaxy surveys. On scales between 1 arcminute and 1 degree the correlation function is well described by a power-law with an exponent of ~ -0.7. The amplitude of the correlation function, within this angular interval, decreases with fainter magnitudes in good agreement with analyses from existing galaxy surveys. There is a characteristic break in the correlation function on scales of approximately 1-2 degrees. On small scales, < 1', the SDSS correlation function does not appear to be consistent with the power-law form fitted to the 1'< theta <0.5 deg data. With a data set that is less than 2% of the full SDSS survey area, we have obtained high precision measurements of the power-law angular correlation function on angular scales 1' < theta < 1 deg, which are robust to systematic uncertainties. Because of the limited area and the highly correlated nature of the error covariance matrix, these initial results do not yet provide a definitive characterization of departures from the power-law form at smaller and larger angles. In the near future, however, the area of the SDSS imaging survey will be sufficient to allow detailed analysis of the small and large scale regimes, measurements of higher-order correlations, and studies of angular clustering as a function of redshift and galaxy type

Synthesis of Organosilicon Ligands for Europium (III) and Gadolinium (III) as Potential Imaging Agents

The relaxivity of MRI contrast agents can be increased by increasing the size of the contrast agent and by increasing concentration of the bound gadolinium. Large multi-site ligands able to coordinate several metal centres show increased relaxivity as a result. In this paper, an “aza-type Michael” reaction is used to prepare cyclen derivatives that can be attached to organosilicon frameworks via hydrosilylation reactions. A range of organosilicon frameworks were tested including silsesquioxane cages and dimethylsilylbenzene derivatives. Michael donors with strong electron withdrawing groups could be used to alkylate cyclen on three amine centres in a single step. Hydrosilylation successfully attached these to mono-, di-, and tri-dimethylsilyl-substituted benzene derivatives. The europium and gadolinium complexes were formed and studied using luminescence spectroscopy and relaxometry. This showed the complexes to contain two bound water moles per lanthanide centre and T1 relaxation time measurements demonstrated an increase in relaxivity had been achieved, in particular for the trisubstituted scaffold 1,3,5-tris((pentane-sDO3A)dimethylsilyl)benzene-Gd3. This showed a marked increase in the relaxivity (13.1 r1p/mM−1s−1)

Penguins and seals transport limiting nutrients between offshore pelagic and coastal regions of Antarctica under changing sea ice

Large animals such as sea birds and marine mammals can transport limiting nutrients between different regions of the ocean, thereby stimulating and enhancing productivity. In Antarctica this process is influenced by formation and breakup of sea ice and its influence on the feeding behaviour of predators and their prey. We used analyses of bioactive metals (for example, Fe, Co, Mn), macronutrients (for example, N) and stable isotopes (δ13C and δ15N) in the excreta of Adélie (Pygoscelis adeliae) and emperor penguins (Aptenodytes forsteri) as well as Weddell seals (Leptonychotes weddellii) from multiple sites, among multiple years (2012–2014) to resolve how changes in sea ice dynamics, as indicated by MODIS satellite images, were coincident with prey switching and likely changes in nutrient fluxes between the offshore pelagic and coastal zones. We also sampled excreta of the south polar skua (Stercorarius maccormicki), which preys on penguins and scavenges the remains of both penguins and seals. We found strong coincidence of isotopic evidence for prey switching, between euphausiids (Euphausia superba and E. crystallorophias) and pelagic/cryopelagic fishes (for example, Pleuragramma antarcticum) in penguins, and between pelagic/cryopelagic fishes and Antarctic toothfish (Dissostichus mawsoni) in Weddell seals, with changes in sea ice cover among years. Further, prey switching was strongly linked to changes in the concentrations of nutrients (Fe and N) deposited in coastal environments by both penguins and seals. Our findings have important implications for understanding how the roles of large animals in supporting coastal productivity may shift with environmental conditions in polar ecosystems.Accepted manuscrip

Discovery of Ghost Cavities in Abell 2597's X-ray Atmosphere

A Chandra image of the central 100 kpc of the Abell 2597 cluster of galaxies shows bright, irregular, X-ray emission within the central dominant cluster galaxy (CDG), and two low surface brightness cavities located 30 kpc from the CDG's nucleus. Unlike the cavities commonly seen in other clusters, Abell 2597's ``ghost'' cavities are not coincident with the bright central radio source. Instead, they appear to be associated with faint, extended radio emission seen in a deep VLA radio map. We interpret the ghost cavities as buoyantly-rising relics of a radio outburst that occurred between 50--100 Myr ago. The demography of cavities in the few clusters studied thus far shows that galactic radio sources experience recurrent outbursts on a $\sim 100$ Myr timescale. Over the lifetime of a cluster, ghost cavities emerging from CDGs deposit \gae 10^{59-61} erg of energy into the intracluster medium. If a significant fraction of this energy is deposited as magnetic field, it would account for the high field strengths in the cooling flow regions of clusters. The similarity between the central cooling time of the keV gas and the radio cycling timescale suggests that feedback between cooling gas and the radio source may be retarding or quenching the cooling flow.Comment: includes two color and two black and white figures. Accepted for publication in the Astrophysical Journa