110,478 research outputs found
Method of resolving clock synchronization error and means therefor Patent
Development of method for synchronizing clocks at several ground stations based on signals received from spacecraft or satellite
Embodying gender, age, ethnicity and power in ‘the field’: Reflections on dress and the presentation of the self in research with older Pakistani Muslims
This article is available open access through the publisher’s website at the link below. Copyright @ 2012 Sociological Research Online.In recent years, there has been an increasing interest in researching people growing older in the South Asian ethnic minority communities in the UK. However, these populations have received comparatively little attention in wide-ranging discussions on culturally and socially appropriate research methodologies. In this paper, we draw on the experiences of a young female Pakistani Muslim researcher researching older Pakistani Muslim women and men, to explore the significance of gender, age and ethnicity to fieldwork processes and 'field' relationships. In particular, we highlight the significance of dress and specific presentations of the embodied self within the research process. We do so by focusing upon three key issues: (1) Insider/Outsider boundaries and how these boundaries are continuously and actively negotiated in the field through the use of dress and specific presentations of the embodied 'self'; (2) The links between gender, age and space - more specifically, how the researcher's use of traditional Pakistani dress, and her differing research relationships, are influenced by the older Pakistani Muslim participants' gendered use of public and private space; and (3) The opportunities and vulnerabilities experienced by the researcher in the field, reinforced by her use (or otherwise) of the traditional and feminine Pakistani Muslim dress. Our research therefore highlights the role of different presentations of the embodied 'self' to fieldwork processes and relationships, and illustrates how age, gender and status intersect to produce fluctuating insider/outsider boundaries as well as different opportunities and experiences of power and vulnerability within research relationships.ESR
Segmented back-up bar Patent
Segmented back-up bar for butt welding large tubular structures such as rocket booster bodies or tank
The case for inflow of the broad-line region of active galactic nuclei
The high-ionization lines of the broad-line region (BLR) of thermal active
galactic nuclei (AGNs) show blueshifts of a few hundred km/s to several
thousand km/sec with respect to the low-ionization lines. This has long been
thought to be due to the high-ionization lines of the BLR arising in a wind of
which the far side of the outflow is blocked from our view by the accretion
disc. Evidence for and against the disc-wind model is discussed. The biggest
problem for the model is that velocity-resolved reverberation mapping
repeatedly fails to show the expected kinematic signature of outflow of the
BLR. The disc-wind model also cannot readily reproduce the red side of the line
profiles of high-ionization lines. The rapidly falling density in an outflow
makes it difficult to obtain high equivalent widths. We point out a number of
major problems with associating the BLR with the outflows producing broad
absorption lines. An explanation which avoids all these problems and satisfies
the constraints of both the line profiles and velocity-resolved
reverberation-mapping is a model in which the blueshifting is due to scattering
off material spiraling inwards with an inflow velocity of half the velocity of
the blueshifting. We discuss how recent reverberation mapping results are
consistent with the scattering-plus-inflow model but do not support a disc-wind
model. We propose that the anti-correlation of the apparent redshifting of
H with the blueshifting of CIV is a consequence of contamination of the
red wings of H by the broad wings of [O III].Comment: 15 pages, 15 figures. To appear in special issue of Astrophysics and
Space Science, "Spectral Line Shapes in Astrophysics
Information Technology and Legal Ethics: Expanding the Teaching and Understanding of Legal Ethics Through the Creation of a New Generation of Electronic Reference Materials
Cramton and Martin present a very brief summary of the inward-looking elements of the Cornell Law School prorgam to improve the basic required course in professional ethics and to encourage the pervasive teaching of the subject throughout the law curriculum. The Cornell program focuses on the preparation and dissemination of electronic material on legal ethics on a state-by-state basis
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Line Shifts, Broad-Line Region Inflow, And The Feeding Of Active Galactic Nuclei
Velocity-resolved reverberation mapping suggests that the broad-line regions (BLRs) of active galactic nuclei (AGNs) can have significant net inflow. We use the STOKES radiative transfer code to show that electron and Rayleigh scattering off the BLR and torus naturally explains the blueshifted profiles of high-ionization lines and the ionization dependence of the blueshifts. This result is insensitive to the geometry of the scattering region. If correct, then this model resolves the long-standing conflict between the absence of outflow implied by velocity-resolved reverberation mapping and the need for outflow if the blueshifting is the result of obscuration. The accretion rate implied by the inflow is sufficient to power the AGN. We suggest that the BLR is part of the outer accretion disk and that similar magnetohydrodynamic processes are operating. In the scattering model, the blueshifting is proportional to the accretion rate so high-accretion-rate AGNs will show greater high-ionization line blueshifts, as is observed. Scattering can lead to systematically too high black hole mass estimates from the C IV line. We note many similarities between narrow-line region (NLR) and BLR blueshiftings, and suggest that NLR blueshiftings have a similar explanation. Our model explains the higher blueshifts of broad absorption line QSOs if they are more highly inclined. Rayleigh scattering from the BLR and torus could be more important in the UV than electron scattering for predominantly neutral material around AGNs. The importance of Rayleigh scattering versus electron scattering can be assessed by comparing line profiles at different wavelengths arising from the same emission-line region.US National Science Foundation AST 03-07912, AST 08-03883Space Telescope Science Institute AR-09926.01GEMINI-CONICYT Fund of Chile 32070017FONDECYT of Chile 1120957French GdR PCHECenter for Theoretical Astrophysics (CTA) through Czech Ministry of Education, Youth and Sports LC06014ANR-11-JS56-013-01Astronom
Interferometric measurement of resonance transition wavelengths in C IV, Si IV, Al III, Al II, and Si II
We have made the first interferomeric measurements of the wavelengths of the
important ultraviolet diagnostic lines in the spectra \ion{C}{4} near 155 nm
and \ion{Si}{4} near 139 nm with a vacuum ultraviolet Fourier transform
spectrometer and high-current discharge sources. The wavelength uncertainties
were reduced by one order of magnitude for the \ion{C}{4} lines and by two
orders of magnitude for the \ion{Si}{4} lines. Our measurements also provide
accurate wavelengths for resonance transitions in \ion{Al}{3}, \ion{Al}{2}, and
\ion{Si}{2}.Comment: 6 pages, 2 figures, 1 tabl
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