1,786 research outputs found
Correlations of Globular Cluster Properties: Their Interpretations and Uses
Correlations among the independently measured physical properties of globular
clusters (GCs) can provide powerful tests for theoretical models and new
insights into their dynamics, formation, and evolution. We review briefly some
of the previous work, and present preliminary results from a comparative study
of GC correlations in the Local Group galaxies. The results so far indicate
that these diverse GC systems follow the same fundamental correlations,
suggesting a commonality of formative and evolutionary processes which produce
them.Comment: An invited review, to appear in "New Horizons in Globular Cluster
Astronomy", eds. G. Piotto, G. Meylan, S.G. Djorgovski, and M. Riello, ASPCS,
in press (2003). Latex file, 8 pages, 5 eps figures, style files include
Recommended from our members
CID-based ICP-AES instrumentation for continuous on-line analysis of aqueous industrial waste streams
A CID detection based ICP-AES instrument has been incorporated into an on-line continuous process monitoring system for analysis of aqueous industrial waste streams. Total wavelength coverage afforded by the CID detection allows increased confidence in the analytical results through use of multiple wavelengths for analysis of each element. Total wavelength coverage also allows quick detection of interferences present in the varying waste stream that may cause false positives. Several internal standards have been evaluated to correct for expected variations in the waste stream matrix, and results have been incorporated in the analytical method. The system has been tested on a surrogate waste stream and results are compared to those obtained through conventional ICP-AES analysis of waste stream grab samples
In-orbit background of X-ray microcalorimeters and its effects on observations
Methods.There are no experimental data about the background experienced by
microcalorimeters in the L2 orbit, and thus the particle background levels were
calculated by means of Monte Carlo simulations: we considered the original
design configuration and an improved configuration aimed to reduce the
unrejected background, and tested them in the L2 orbit and in the low Earth
orbit, comparing the results with experimental data reported by other X-ray
instruments.To show the results obtainable with the improved configuration we
simulated the observation of a faint, high-redshift, point source (F[0.5-10
keV]~6.4E-16 erg cm-2 s-1, z=3.7), and of a hot galaxy cluster at R200
(Sb[0.5-2 keV]=8.61E-16 erg cm-2 s-1 arcmin-2,T=6.6 keV). Results.First we
confirm that implementing an active cryogenic anticoincidence reduces the
particle background by an order of magnitude and brings it close to the
required level.The implementation and test of several design solutions can
reduce the particle background level by a further factor of 6 with respect to
the original configuration.The best background level achievable in the L2 orbit
with the implementation of ad-hoc passive shielding for secondary particles is
similar to that measured in the more favorable LEO environment without the
passive shielding, allowing us to exploit the advantages of the L2 orbit.We
define a reference model for the diffuse background and collect all the
available information on its variation with epoch and pointing direction.With
this background level the ATHENA mission with the X-IFU instrument is able to
detect ~4100 new obscured AGNs with F>6.4E-16 erg cm-2 s-1 during three years,
to characterize cluster of galaxies with Sb(0.5-2 keV)>9.4E-16 erg cm-2 s-1
sr-1 on timescales of 50 ks (500 ks) with errors <40% (<12%) on
metallicity,<16% (4.8%) on temperature,2.6% (0.72%) on the gas density, and
several single-element abundances.Comment: the PDF has poor quality, it will be improved in the futur
IT Value in Public Administrations: a Model Proposal for E-Procurement
Recent studies have affirmed the necessity of a discontinuity in the method of investigating the value produced in organisations by IT. Existing studies have in common a prevailing (when not exclusive) attention paid to the private sector, as testified by the frequent use of income or financial indicators to measure benefits. These approaches however cannot be directly applied to public utility organisations like public administrations. Taking into account this scenario, the present exploratory work looks at the analysis of IT investments in the public sector by identifying a viable approach to research in this domain. To move towards this objective, procurement management has been taken as the field to be observed, and an Italian publich Local Healthcare Agency which has managed several e-procurement projects has been analysed. This case represents a valuable context for examination and discussion because the outcomes of each project were evaluated in details. A riche IT Value Model devoted to the private secotr has been adopted and discussed, and later some resulting adaptations are suggested, together with some hints and limitations.Recent studies have affirmed the necessity of a discontinuity in the method of investigating the value produced in organisations by IT. Existing studies have in common a prevailing (when not exclusive) attention paid to the private sector, as testified by the frequent use of income or financial indicators to measure benefits. These approaches however cannot be directly applied to public utility organisations like public administrations. Taking into account this scenario, the present exploratory work looks at the analysis of IT investments in the public sector by identifying a viable approach to research in this domain. To move towards this objective, procurement management has been taken as the field to be observed, and an Italian publich Local Healthcare Agency which has managed several e-procurement projects has been analysed. This case represents a valuable context for examination and discussion because the outcomes of each project were evaluated in details. A riche IT Value Model devoted to the private secotr has been adopted and discussed, and later some resulting adaptations are suggested, together with some hints and limitations.Monograph's chapter
Feminist solidarity building as embodied agonism: An ethnographic account of a protest movement
Feminist solidarity, after early and idealistic conceptions of an allâencompassing sisterhood, has become preoccupied with understanding and theorising differences between women. This study develops an account of solidarity as embodied agonism, where difference and contest are experienced and negotiated through the body. Difference and contest are reframed within feminist solidarity projects as resources for, rather than inhibitors to, generating collective agency. This is done through an ethnography of a protest movement in Montenegro, which drew together diverse groups of women, and bring our data into conversation with theories of agonistic democratic practice and embodied performativity. Embodied agonistic solidarity is theorised as a participative and inclusive endeavour driven by conflictual encounters, constituted through the bodies, language and visual imagery of assembling and articulating subjects. Our account of solidarity is presented as constituted through three dimensions, each of which represents a different emphasis on sensory experience: exposing, which is to make one's body open to the hardship of others, enabling alliances between unlikely allies to emerge; citing, which is to draw on othersâ symbolic resources and to publicly affirm them; inhabiting, which is to embody the deprivations of others, enabling alliances to grow and persist
Solitary magnetic perturbations at the ELM onset
Edge localised modes (ELMs) allow maintaining sufficient purity of tokamak
H-mode plasmas and thus enable stationary H-mode. On the other hand in a future
device ELMs may cause divertor power flux densities far in excess of tolerable
material limits. The size of the energy loss per ELM is determined by
saturation effects in the non-linear phase of the ELM, which at present is
hardly understood. Solitary magnetic perturbations (SMPs) are identified as
dominant features in the radial magnetic fluctuations below 100kHz. They are
typically observed close (+-0.1ms) to the onset of pedestal erosion. SMPs are
field aligned structures rotating in the electron diamagnetic drift direction
with perpendicular velocities of about 10km/s. A comparison of perpendicular
velocities suggests that the perturbation evoking SMPs is located at or inside
the separatrix. Analysis of very pronounced examples showed that the number of
peaks per toroidal turn is 1 or 2, which is clearly lower than corresponding
numbers in linear stability calculations. In combination with strong peaking of
the magnetic signals this results in a solitary appearance resembling modes
like palm tree modes, edge snakes or outer modes. This behavior has been
quantified as solitariness and correlated to main plasma parameters. SMPs may
be considered as a signature of the non-linear ELM-phase originating at the
separatrix or further inside. Thus they provide a handle to investigate the
transition from linear to non-linear ELM phase. By comparison with data from
gas puff imaging processes in the non-linear phase at or inside the separatrix
and in the scrape-off-layer (SOL) can be correlated. A connection between the
passing of an SMP and the onset of radial filament propagation has been found.
Eventually the findings related to SMPs may contribute to a future quantitative
understanding of the non-linear ELM evolution.Comment: submitted to Nuclear Fusio
Bleeding from gastrointestinal angioectasias is not related to bleeding disorders - a case control study
n/aOriginal Publication:Charlotte M Hoog, Olle Brostrom, Tomas Lindahl, Andreas Hillarp, Gerd Larfars and Urban Sjoqvist, Bleeding from gastrointestinal angioectasias is not related to bleeding disorders - a case control study, 2010, BMC GASTROENTEROLOGY, (10), 113.http://dx.doi.org/10.1186/1471-230X-10-113Licensee: BioMed Centralhttp://www.biomedcentral.com
- âŠ