4,572 research outputs found
Tracking the reflexivity of the (dis)engaged citizen: some methodological reflections
The relationship between governments and citizens in many contemporary democracies is haunted by uncertainty and sociologists face the task of listening effectively to citizensâ own reflections on this uncertain relationship. This article reflects on the qualitative methodology of a recently completed UK project which used a combination of diary and multiple interviews/ focus groups to track over a fieldwork period of up to a year citizensâ reflections on their relationship to a public world and the contribution to this of their media consumption. In particular, the article considers how the projectâs multiple methods enabled multiple angles on the inevitable artificiality and performative dimension of the diary process, resulting in rich data on peopleâs complex reflections on the uncertain position of the contemporary citizen
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Getting it right: a model for compliance assessment
Compliance is important for organisations but models and tools to aid understanding of compliance behaviour is limited. This paper argues that the understanding of the interaction between subjects and objects and their intention to comply with requirements of rules and regulations may be a predictor of compliance behaviour. Thus, a Conceptual Compliance Assessment Model (CAM) is developed by extension of Technology Acceptance Model and Activity theory for assessment of compliance behaviour. Data collected and evaluated showed that the awareness and understanding of the mediational tool is critical in realizing the outcome. It also showed that other factors like the perceived usefulness, perceived ease of use, the community and the management set up also affected compliance behaviour. Essentially, the use of CAM will be useful in assessing the compliance activities of subjects which may aid in formulation of behaviour support systems to improve compliance behaviour
JWST MIRI and NIRCam Unveil Previously Unseen Infrared Stellar Populations in NGC 6822
NGC 6822 is a nearby (\sim490 kpc) non-interacting low-metallicity (0.2
Z_\odot) dwarf galaxy which hosts several prominent Hii regions, including
sites of highly embedded active star formation. In this work, we present an
imaging survey of NGC 6822 conducted with the NIRCam and MIRI instruments
onboard JWST. We provide a description of the data reduction, source
extraction, and stellar population identifications from combined near- and
mid-infrared (IR) photometry. Our NIRCam observations reach seven magnitudes
deeper than previous JHKs surveys of this galaxy, which were sensitive to just
below the tip of the red giant branch (TRGB). These JWST observations thus
reveal for the first time in the near-IR the red clump stellar population and
extend nearly three magnitudes deeper. In the mid-IR, we observe roughly two
magnitudes below the TRGB with the MIRI F770W and F1000W filters. With these
improvements in sensitivity, we produce a catalogue of \sim900,000 point
sources over an area of \sim 6.0 x 4.3 arcmin2. We present several NIRCam and
MIRI colour-magnitude diagrams and discuss which colour combinations provide
useful separations of various stellar populations to aid in future JWST
observation planning. Finally, we find populations of carbon- and oxygen-rich
asymptotic giant branch stars which will assist in improving our understanding
of dust production in low-metallicity, early Universe analogue galaxies
Gas Accretion via Lyman Limit Systems
In cosmological simulations, a large fraction of the partial Lyman limit
systems (pLLSs; 16<log N(HI)<17.2) and LLSs (17.2log N(HI)<19) probes
large-scale flows in and out of galaxies through their circumgalactic medium
(CGM). The overall low metallicity of the cold gaseous streams feeding galaxies
seen in these simulations is the key to differentiating them from metal rich
gas that is either outflowing or being recycled. In recent years, several
groups have empirically determined an entirely new wealth of information on the
pLLSs and LLSs over a wide range of redshifts. A major focus of the recent
research has been to empirically determine the metallicity distribution of the
gas probed by pLLSs and LLSs in sizable and representative samples at both low
(z2) redshifts. Here I discuss unambiguous evidence for
metal-poor gas at all z probed by the pLLSs and LLSs. At z<1, all the pLLSs and
LLSs so far studied are located in the CGM of galaxies with projected distances
<100-200 kpc. Regardless of the exact origin of the low-metallicity pLLSs/LLSs,
there is a significant mass of cool, dense, low-metallicity gas in the CGM that
may be available as fuel for continuing star formation in galaxies over cosmic
time. As such, the metal-poor pLLSs and LLSs are currently among the best
observational evidence of cold, metal-poor gas accretion onto galaxies.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
Springe
New Particles Working Group Report of the Snowmass 2013 Community Summer Study
This report summarizes the work of the Energy Frontier New Physics working
group of the 2013 Community Summer Study (Snowmass)
Gas Accretion and Star Formation Rates
Cosmological numerical simulations of galaxy evolution show that accretion of
metal-poor gas from the cosmic web drives the star formation in galaxy disks.
Unfortunately, the observational support for this theoretical prediction is
still indirect, and modeling and analysis are required to identify hints as
actual signs of star-formation feeding from metal-poor gas accretion. Thus, a
meticulous interpretation of the observations is crucial, and this
observational review begins with a simple theoretical description of the
physical process and the key ingredients it involves, including the properties
of the accreted gas and of the star-formation that it induces. A number of
observations pointing out the connection between metal-poor gas accretion and
star-formation are analyzed, specifically, the short gas consumption time-scale
compared to the age of the stellar populations, the fundamental metallicity
relationship, the relationship between disk morphology and gas metallicity, the
existence of metallicity drops in starbursts of star-forming galaxies, the
so-called G dwarf problem, the existence of a minimum metallicity for the
star-forming gas in the local universe, the origin of the alpha-enhanced gas
forming stars in the local universe, the metallicity of the quiescent BCDs, and
the direct measurements of gas accretion onto galaxies. A final section
discusses intrinsic difficulties to obtain direct observational evidence, and
points out alternative observational pathways to further consolidate the
current ideas.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
Springe
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
Constraints on the Ď_(c1) versus Ď_(c2) polarizations in proton-proton collisions at âs = 8 TeV
The polarizations of promptly produced Ď_(c1) and Ď_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at âs=8ââTeV. The Ď_c states are reconstructed via their radiative decays Ď_c â J/ĎÎł, with the photons being measured through conversions to eâşeâť, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the Ď_(c2) to Ď_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/Ď â ÎźâşÎźâť decay, in three bins of J/Ď transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
The azimuthal anisotropy of charged particles in PbPb collisions at
nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS
detector at the LHC over an extended transverse momentum (pt) range up to
approximately 60 GeV. The data cover both the low-pt region associated with
hydrodynamic flow phenomena and the high-pt region where the anisotropies may
reflect the path-length dependence of parton energy loss in the created medium.
The anisotropy parameter (v2) of the particles is extracted by correlating
charged tracks with respect to the event-plane reconstructed by using the
energy deposited in forward-angle calorimeters. For the six bins of collision
centrality studied, spanning the range of 0-60% most-central events, the
observed v2 values are found to first increase with pt, reaching a maximum
around pt = 3 GeV, and then to gradually decrease to almost zero, with the
decline persisting up to at least pt = 40 GeV over the full centrality range
measured.Comment: Replaced with published version. Added journal reference and DO
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