4,069 research outputs found
Searching for additional heating - [OII] emission in the diffuse ionized gas of NGC891, NGC4631 and NGC3079
We present spectroscopic data of ionized gas in the disk--halo regions of
three edge-on galaxies, NGC 891, NGC 4631 and NGC 3079, covering a wavelength
range from [\ion{O}{2}] 3727\AA to [\ion{S}{2}] 6716.4\AA.
The inclusion of the [\ion{O}{2}] emission provides new constraints on the
properties of the diffuse ionized gas (DIG), in particular, the origin of the
observed spatial variations in the line intensity ratios. We used three
different methods to derive electron temperatures, abundances and ionization
fractions along the slit. The increase in the [\ion{O}{2}]/H line ratio
towards the halo in all three galaxies requires an increase either in electron
temperature or in oxygen abundance. Keeping the oxygen abundance constant
yields the most reasonable results for temperature, abundances, and ionization
fractions. Since a constant oxygen abundance seems to require an increase in
temperature towards the halo, we conclude that gradients in the electron
temperature play a significant role in the observed variations in the optical
line ratios from extraplanar DIG in these three spiral galaxies.Comment: 43 pages, 29 figure
Process, People, Power and Conflict: Some Lessons from a Participatory Policy Process in Andhra Pradesh, India
A large body of empirical literature highlights the need for stakeholder participation within the context of policy change and democratic governance. This makes intuitive sense and may appear to be a straightforward process of managing conflicting interests, building consensus, and lining up support. The reality, however, is often much more complicated and conflictive, even where there is general agreement on the policy objectives. The present paper examines these issues in the context of participatory policy development for the delivery of veterinary services by para-professionals in the Indian state of Andhra Pradesh. It illustrates the challenges inherent in the politics of participatory policy processes and the potential of ‘agenda hijack’ by influential partners, resulting in missed learning opportunities. It also offers insights on practical steps to counter these dangers, as potential lessons for practitioners and project managers engaged in participatory policy reform processes.
A Product Life Cycle Ontology for Additive Manufacturing
The manufacturing industry is evolving rapidly, becoming more complex, more interconnected, and more geographically distributed. Competitive pressure and diversity of consumer demand are driving manufacturing companies to rely more and more on improved knowledge management practices. As a result, multiple software systems are being created to support the integration of data across the product life cycle. Unfortunately, these systems manifest a low degree of interoperability, and this creates problems, for instance when different enterprises or different branches of an enterprise interact. Common ontologies (consensus-based controlled vocabularies) have proved themselves in various domains as a valuable tool for solving such problems. In this paper, we present a consensus-based Additive Manufacturing Ontology (AMO) and illustrate its application in promoting re-usability in the field of dentistry product manufacturing
Experimental Philosophy, Robert Kane, and the Concept of Free Will
Trends in experimental philosophy have provided new and compelling results that are cause for re-evaluations in contemporary discussions of free will. In this paper, I argue for one such re-evaluation by criticizing Robert Kane’s well-known views on free will. I argue that Kane’s claims about pre-theoretical intuitions are not supported by empirical findings on two accounts. First, it is unclear that either incompatibilism or compatibalism is more intuitive to nonphilosophers, as different ways of asking about free will and responsibility reveal different answers. Secondly, I discuss how a study by Josh May supporting a cluster concept of free will may provide ethicists with a reason to give up a definitional model, and I discuss a direction future work might take. Both of these objections come from a larger project concerned with understanding the cognitive mechanisms that people employ when they make judgments about agency and responsibility—a project that promises not only to challenge contemporary philosophy, but to inform it
Mesoscopic anisotropic magnetoconductance fluctuations in ferromagnets
The conductance of a ferromagnetic particle depends on the relative
orientation of the magnetization with respect to the direction of current flow.
This phenomenon is known as "anisotropic magnetoresistance". Quantum
interference leads to an additional, random dependence of the conductance on
the magnetization direction. These "anisotropic magnetoresistance fluctuations"
are caused by spin-orbit scattering, which couples the electron motion to the
exchange field in the ferromagnet. We report a calculation of the dependence of
the conductance autocorrelation function on the rotation angle of the
magnetization direction.Comment: 4 pages, 3 figures, revtex
Magneto-quantum oscillations of the conductance of a tunnel point-contact in the presence of a single defect
The influence of a quantizing magnetic field to the conductance of a
tunnel point contact in the presence of the single defect has been considered.
We demonstrate that the conductance exhibits specific magneto-quantum
oscillations, the amplitude and period of which depend on the distance between
the contact and the defect. We show that a non-monotonic dependence of the
point-contact conductance results from a superposition of two types of
oscillations: A short period oscillation arising from electron focusing by the
field and a long period oscillation of Aharonov-Bohm-type originated from
the magnetic flux passing through the closed trajectories of electrons moving
from the contact to the defect and returning back to the contact.Comment: 13 pages, 3 figure
Controlled complete suppression of single-atom inelastic spin and orbital cotunnelling
The inelastic portion of the tunnel current through an individual magnetic
atom grants unique access to read out and change the atom's spin state, but it
also provides a path for spontaneous relaxation and decoherence. Controlled
closure of the inelastic channel would allow for the latter to be switched off
at will, paving the way to coherent spin manipulation in single atoms. Here we
demonstrate complete closure of the inelastic channels for both spin and
orbital transitions due to a controlled geometric modification of the atom's
environment, using scanning tunnelling microscopy (STM). The observed
suppression of the excitation signal, which occurs for Co atoms assembled into
chain on a CuN substrate, indicates a structural transition affecting the
d orbital, effectively cutting off the STM tip from the spin-flip
cotunnelling path.Comment: 4 figures plus 4 supplementary figure
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