527 research outputs found
Near-Infrared photometry and spectroscopy of NGC 6539 and UKS 1: two intermediate metallicity Bulge Globular Clusters
Using the SofI imager at ESO/NTT and NIRSPEC spectrograph at KeckII, we have
obtained J,K images and echelle spectra covering the range 1.5 - 1.8 micron for
the intermediate metallicity Bulge globular clusters NGC6539 and UKS1. We find
[Fe/H]=-0.76 and -0.78, respectively, and an average alpha-enhancement of +0.44
dex and +0.31 dex, consistent with previous measurements of metal rich Bulge
clusters, and favoring the scenario of rapid chemical enrichment. We also
measure very low 12C/13C=4.5 +/-1 isotopic ratios in both clusters, suggesting
that extra-mixing mechanisms due to cool bottom processing are at work during
the evolution along the Red Giant Branch. Finally, we measure accurate radial
velocities of =+31 +/-4Km/s and =+57 +/-6Km/s and velocity dispersion
of about 8 Km/s and 11 Km/s for NGC6539 and UKS1, respectively.Comment: 10 pages, 7 figures, accepted for publication at MNRA
Timeline analysis and wavelet multiscale analysis of the AKARI All-Sky Survey at 90 micron
We present a careful analysis of the point source detection limit of the
AKARI All-Sky Survey in the WIDE-S 90 m band near the North Ecliptic Pole
(NEP). Timeline Analysis is used to detect IRAS sources and then a conversion
factor is derived to transform the peak timeline signal to the interpolated 90
m flux of a source. Combined with a robust noise measurement, the point
source flux detection limit at S/N for a single detector row is
Jy which corresponds to a point source detection limit of the
survey of 0.4 Jy.
Wavelet transform offers a multiscale representation of the Time Series Data
(TSD). We calculate the continuous wavelet transform of the TSD and then search
for significant wavelet coefficients considered as potential source detections.
To discriminate real sources from spurious or moving objects, only sources with
confirmation are selected. In our multiscale analysis, IRAS sources selected
above can be identified as the only real sources at the Point Source
Scales. We also investigate the correlation between the non-IRAS sources
detected in Timeline Analysis and cirrus emission using wavelet transform and
contour plots of wavelet power spectrum. It is shown that the non-IRAS sources
are most likely to be caused by excessive noise over a large range of spatial
scales rather than real extended structures such as cirrus clouds.Comment: 16 pages, 19 figures, 5 tables, accepted for publication in MNRA
Near-Infrared photometry of four metal-rich Bulge globular clusters: NGC6304, NGC6569, NGC6637, NGC6638
We present high-quality near-Infrared photometry of four Bulge metal-rich
globular clusters, namely: NGC 6304, NGC 6569, NGC 6637 and NGC 6638. By using
the observed Colour-Magnitude Diagrams we derived a photometric estimates of
the cluster reddening and distance. We performed a detailed analysis of the Red
Giant Branch, presenting a complete description of morphologic parameters and
evolutionary features (Bump and Tip). Photometric estimates of the cluster
metallicity have been obtained by using the updated set of relations (published
by our group) linking the metal abundance to a variety of near-Infrared indices
measured along the Red Giant Branch. The detection of the Red Giant Branch Bump
and the Tip is also presented and briefly discussed.Comment: 12 pages, 15 figures, accepted for publication in MNRA
Adaptive Motor Imagery: A Multimodal Study of Immobilization-Induced Brain Plasticity.
The consequences of losing the ability to move a limb are traumatic. One approach that examines the impact of pathological limb nonuse on the brain involves temporary immobilization of a healthy limb. Here, we investigated immobilization-induced plasticity in the motor imagery (MI) circuitry during hand immobilization. We assessed these changes with a multimodal paradigm, using functional magnetic resonance imaging (fMRI) to measure neural activation, magnetoencephalography (MEG) to track neuronal oscillatory dynamics, and transcranial magnetic stimulation (TMS) to assess corticospinal excitability. fMRI results show a significant decrease in neural activation for MI of the constrained hand, localized to sensorimotor areas contralateral to the immobilized hand. MEG results show a significant decrease in beta desynchronization and faster resynchronization in sensorimotor areas contralateral to the immobilized hand. TMS results show a significant increase in resting motor threshold in motor cortex contralateral to the constrained hand, suggesting a decrease in corticospinal excitability in the projections to the constrained hand. These results demonstrate a direct and rapid effect of immobilization on MI processes of the constrained hand, suggesting that limb nonuse may not only affect motor execution, as evidenced by previous studies, but also MI. These findings have important implications for the effectiveness of therapeutic approaches that use MI as a rehabilitation tool to ameliorate the negative effects of limb nonuse
The First Detection of Cobalt in a Damped Lyman Alpha System
We present the first ever detection of Cobalt in a Damped Lyman Alpha system
(DLA) at z = 1.92. In addition to providing important clues to the star
formation history of these high redshift galaxies, we discuss how studying the
Co abundance in DLAs may also help to constrain models of stellar
nucleosynthesis in a regime not probed by Galactic stars.Comment: 4 pages, to appear in the proceedings of `New Quests in Stellar
Astrophysics: The Link Between Stars and Cosmology', eds. M. Chavez, A.
Bressan, A. Buzzoni, D. Mayy
The population of variable stars in M54 (NGC6715)
We present new B, V and I CCD time-series photometry for 177 variable stars
in a 13'X 13' field centered on the globular cluster M54 (lying at the center
of the Sagittarius dwarf spheroidal galaxy), 94 of which are newly identified
variables. The total sample is composed of 2 anomalous Cepheids, 144 RR Lyrae
stars (108 RR0 and 36 RR1), 3 SX Phoenicis, 7 eclipsing binaries (5 W UMA and 2
Algol binaries), 3 variables of uncertain classification and 18 long-period
variables. The large majority of the RR Lyrae variables likely belong to M54.
Ephemerides are provided for all the observed short-period variables. The
pulsational properties of the M54 RR Lyrae variables are close to those of
Oosterhoff I clusters, but a significant number of long-period ab type RR Lyrae
are present. We use the observed properties of the RR Lyrae to estimate the
reddening and the distance modulus of M54, E(B-V)=0.16 +/- 0.02 and
(m-M)_0=17.13 +/- 0.11, respectively, in excellent agreement with the most
recent estimates. The metallicity has been estimated for a subset of 47 RR
Lyrae stars, with especially good quality light curves, from the Fourier
parameters of the V light curve. The derived metallicity distribution has a
symmetric bell shape, with a mean of =-1.65 and a standard deviation
sigma=0.16 dex. Seven stars have been identified as likely belonging to the
Sagittarius galaxy, based on their too high or too low metallicity. This
evidence, if confirmed, might suggest that old stars in this galaxy span a wide
range of metallicities.Comment: 15 pages, 11 figures, accepted for publication by MNRA
The Public Assistance Policies of Cities and the Justice Concerns of Elected Officials: The Centrality of the Floors Principle in Addressing Urban Poverty
City councils are significant, though seldom central, actors in local policy networks providing public assistance to disadvantaged residents. Mayors and council members in 12 American cities more often support than oppose public assistance initiatives. They claim that their own normative judgments are more important to their preferences and voting behavior on such matters than are public opinion, group demands, or economic considerations. While such elected officials hold a variety of justice principles, the most important of these affecting their positions on public assistance issues is the “floors” principle. A broad ethical commitment to providing social minimums enhances support for living-wage ordinances, for linking subsidies for economic development to assistance to less advantaged citizens, and for exempting spending on social services from budget cuts. We discuss the implications of these findings for major theories of urban politics and policies—collective-action theory, regime theory, and pluralism—and for advocates on behalf of the urban poor
Control of electron transport routes through redox-regulated redistribution of respiratory complexes
Report of Seminar on Law and Medicine
Reports from the UK/CLE Seminar on Law and Medicine held May 26-28, 1976
The British Labour Party and the Antisemitism Crisis: Jeremy Corbyn and Image Repair Theory
This article utilises the work of William Benoit on image repair theory as a framework for examining the crisis communication of Jeremy Corbyn in relation to antisemitism within the Labour Party. By examining the self-defence rhetoric of Corbyn on the antisemitism allegations, the article identifies the following. Of the five strategies for crisis communication, Corbyn was overly reliant on denial, evading responsibility and reducing offensiveness; struggled to explain his attempts at corrective action; and reverted to accepting responsibility – that is, apologies – reluctantly and belatedly. Utilising existing perspectives on the most effective strategies for image repair – which emphasise the importance of effective corrective action and accepting responsibility at the expense of denial, evading responsibility and reducing effectiveness – the article argues that Corbyn undermined his own attempts at image repair in the crisis that defined his leadership
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