2,126 research outputs found
The Impact of Galactic Disc Environment on Star-Forming Clouds
We explore the effect of different galactic disc environments on the
properties of star-forming clouds through variations in the background
potential in a set of isolated galaxy simulations. Rising, falling and flat
rotation curves expected in halo dominated, disc dominated and Milky Way-like
galaxies were considered, with and without an additional two-arm spiral
potential. The evolution of each disc displayed notable variations that are
attributed to different regimes of stability, determined by shear and
gravitational collapse. The properties of a typical cloud were largely
unaffected by the changes in rotation curve, but the production of small and
large cloud associations was strongly dependent on this environment. This
suggests that while differing rotation curves can influence where clouds are
initially formed, the average bulk properties are effectively independent of
the global environment. The addition of a spiral perturbation made the greatest
difference to cloud properties, successfully sweeping the gas into larger,
seemingly unbound, extended structures and creating large arm-interarm
contrasts.Comment: Accepted to MNRAS on 3rd December, 201
Introduction
Introduction to volume 6 of Macalester College\u27s journal Tapestries: Interwoven voices of local and global identities
The development of turbulent pipe flow
Whilst turbulence still remains one of the great mysteries of classical physics, its reputation for a chaotic lack of structure is under intense scrutiny. Research now points to the existence of highly organized large-scale structures within turbulent flows. Much of this research have almost exclusively been carried out within a so called fully-developed region of flow. This region is downstream of a point beyond which the flow field’s behavior is invariant. However, it has not been conclusively proven that a fully developed region actually exists. A literature survey found that most facilities are cited as being ‘sufficiently long’, yet no formal definition or documentary evidence of the fully developed condition is widely accepted. The aim of the study is to produce a detailed analysis of the flow from the uniform inlet conditions through to the fully-developed turbulent state, along with an accurate definition of what constitutes fully developed flow. This investigation concerns the affect of both the growth of large-scale structures and their role in the evolution of the flow to the fully-developed condition. With the increasing acceptance of the turbulent large-scale structures model, previous research has not yet shown how large-scale structures affect this development length. These aims were achieved by the design, development and deployment of a carriage to transport hot-wires within the pipe allowing measurements at any stream wise point within the working sectio
Internet pathways for stakeholder engagement and accountability: universities in the United Kingdom and their donors
Paper presented to the Accounting and Finance Association of Australia and New Zealand Annual Conference, Sydney, Australia, July 2008Universities world-wide experiencing reducing government financial support are seeking to satisfy financial shortfalls through alternative funding such as that from private contributors (especially alumni). When private corporations search for new funding streams, they turn to the internet, however the unregulated nature of internet reporting has brought calls for higher standards in internet reporting practices (e.g. IASC, 1999). Little is known about the use or quality of internet financial reporting by universities to attract private contributions or to account for the stewardship to current contributors.
The present research examined universities' current reporting practices, in order to understand more fully how contextual factors in the tertiary sector impact the availability and quality of universities' internet reporting. The research shows that the ease of accessibility of financial information on universities' websites is related to generic characteristics, such as the age and the financial status of universities. As well, quality of this unregulated internet financial varies widely.
The research expands on the relevant issues emerging from this unregulated environment and highlights gaps that exist between stakeholder's expectations and current internet practice. This study recommends improvements in the standard and quality of reporting in order for universities to discharge their accountabilit
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Multi-scale cellular engineering: From molecules to organ-on-a-chip.
Recent technological advances in cellular and molecular engineering have provided new insights into biology and enabled the design, manufacturing, and manipulation of complex living systems. Here, we summarize the state of advances at the molecular, cellular, and multi-cellular levels using experimental and computational tools. The areas of focus include intrinsically disordered proteins, synthetic proteins, spatiotemporally dynamic extracellular matrices, organ-on-a-chip approaches, and computational modeling, which all have tremendous potential for advancing fundamental and translational science. Perspectives on the current limitations and future directions are also described, with the goal of stimulating interest to overcome these hurdles using multi-disciplinary approaches
Counterdiabatic control of transport in a synthetic tight-binding lattice
Quantum state transformations that are robust to experimental imperfections
are important for applications in quantum information science and quantum
sensing. Counterdiabatic (CD) approaches, which use knowledge of the underlying
system Hamiltonian to actively correct for diabatic effects, are powerful tools
for achieving simultaneously fast and stable state transformations. Protocols
for CD driving have thus far been limited in their experimental implementation
to discrete systems with just two or three levels, as well as bulk systems with
scaling symmetries. Here, we extend the tool of CD control to a discrete
synthetic lattice system composed of as many as nine sites. Although this
system has a vanishing gap and thus no adiabatic support in the thermodynamic
limit, we show that CD approaches can still give a substantial, several
order-of-magnitude, improvement in fidelity over naive, fast adiabatic
protocols.Comment: 10 pages (+2 supplementary), 4 figure
Masticatory muscle pain before, during, and after treatment with orthopedic protraction headgear: A pilot study
Protraction headgear has been used in conjunction with a palatal expansion appliance to correct Class III malocclusion with maxillary deficiency and/or mandibular prognathism. In general, 800 gm of orthopedic force is used to protract the maxilla, and 75% of this force is transmitted to the temporomandibular joint (TMJ) area via the mandible. The effect of this heavy intermittent force on the TMJ has not been reported in the literature. The objectives of this study were to determine the level of masticatory muscle pain and EMG activity in patients treated with maxillary protraction headgear. Ten patients with skeletal Class III malocclusion whose treatment plan called for maxillary protraction headgear treatment participated in this study. Nocturnal masticatory muscle activity was determined using a portable electromyographic (EMG) recording device. Subjects wore the EMG device 14 nights before treatment, 14 nights during treatment, and 14 nights 1 month after active treatment. Masticatory muscle pain level was determined by muscle palpation, scored on a scale of 0 to 3 each period, according to the method of Gross and Gale. The examiner followed a sequence outlined by Burch to examine the masticatory muscles. Results showed no significant differences for masticatory muscle activities before, during, and after treatment. Only a few patients experienced level 1 masticatory pain during treatment. None of the patients experienced masticatory muscle pain 1 month after treatment. These results demonstrate no significant increase in masticatory muscle activity or muscle pain associated with orthopedic treatment using maxillary protraction headgear.published_or_final_versio
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