29,908 research outputs found
The Kinematic and Spatial Deployment of Compact, Isolated High-Velocity Clouds
We have identified a class of high-velocity clouds which are compact and
apparently isolated. The clouds are compact in that they have angular sizes
less than 2 degrees FWHM. They are isolated in that they are separated from
neighboring emission by expanses where no emission is seen to the detection
limit of the available data. Candidates for inclusion in this class were
extracted from the Leiden/Dwingeloo HI survey of Hartmann & Burton and from the
Wakker & van Woerden catalogue of high-velocity clouds. The candidates were
subject to independent confirmation using either the 25-meter telescope in
Dwingeloo or the 140-foot telescope in Green Bank. We argue that the resulting
list, even if incomplete, is sufficiently representative of the ensemble of
compact, isolated HVCs - CHVCs - that the characteristics of their disposition
on the sky, and of their kinematics, are revealing of some physical aspects of
the class. The CHVCs are in fact distributed quite uniformly across the sky. A
global search for the reference frame which minimizes the velocity dispersion
of the ensemble returns the Local Group Standard of Rest with high confidence.
The CHVCs are not stationary with respect to this reference frame but have a
mean infall velocity of 100 km/s. These properties are strongly suggestive of a
population which has as yet had little interaction with the more massive Local
Group members. At a typical distance of about 1 Mpc these objects would have
sizes of about 15 kpc and gas masses, M_HI, of a few times 10^7 M_Sun,
corresponding to those of (sub-)dwarf galaxies. (abridged)Comment: 13 page LaTeX, requires aa.cls and rotate.sty, 5 GIF figures.
Accepted for publication in A&
Sports Marketing Ethics in Today\u27s Marketplace
Sports marketing is a fast-growing business endeavor. However, certain aspects of it have drawn criticisms from several corners (e.g., media, government, coaches, and fans). This paper raises a number of ethical questions about various dimensions of sports marketing. Advice for addressing some of the ethical problems that occur is provided. The paper specifically asks if organizations using professional sports associations as a promotional lever for increasing sales can be hurt by a lack of ethics on the part of the leagues, teams, or players. It also implies that sport organizations, regardless of economic benefits derived or strong player unions, have an obligation to create a positive and sustainable ethical climate and deliver an enforceable ethical code
On the stability of travelling waves with vorticity obtained by minimisation
We modify the approach of Burton and Toland [Comm. Pure Appl. Math. (2011)]
to show the existence of periodic surface water waves with vorticity in order
that it becomes suited to a stability analysis. This is achieved by enlarging
the function space to a class of stream functions that do not correspond
necessarily to travelling profiles. In particular, for smooth profiles and
smooth stream functions, the normal component of the velocity field at the free
boundary is not required a priori to vanish in some Galilean coordinate system.
Travelling periodic waves are obtained by a direct minimisation of a functional
that corresponds to the total energy and that is therefore preserved by the
time-dependent evolutionary problem (this minimisation appears in Burton and
Toland after a first maximisation). In addition, we not only use the
circulation along the upper boundary as a constraint, but also the total
horizontal impulse (the velocity becoming a Lagrange multiplier). This allows
us to preclude parallel flows by choosing appropriately the values of these two
constraints and the sign of the vorticity. By stability, we mean conditional
energetic stability of the set of minimizers as a whole, the perturbations
being spatially periodic of given period.Comment: NoDEA Nonlinear Differential Equations and Applications, to appea
Service provider difficulties in operationalising coercive control
We examined perspectives of social workers, police officers, and specialist domestic abuse practitioners about their perceived ability and organizational readiness to respond effectively to incidents of coercive and controlling behavior. Interviews revealed intervention and risk assessment strategies structured around an outdated, maladaptive concept of domestic abuse as an unambiguous and violent event and frontline services that lacked appreciation of the power dynamics inherent in controlling relationships. The analysis demonstrates how lack of definitional clarity around nonphysical domestic abuse can increase the use of discretion by frontline services and, by extension, increase the discounting of coercive control by pressured frontline officers
Viscous to Inertial Crossover in Liquid Drop Coalescence
Using an electrical method and high-speed imaging we probe drop coalescence
down to 10 ns after the drops touch. By varying the liquid viscosity over two
decades, we conclude that at sufficiently low approach velocity where
deformation is not present, the drops coalesce with an unexpectedly late
crossover time between a regime dominated by viscous and one dominated by
inertial effects. We argue that the late crossover, not accounted for in the
theory, can be explained by an appropriate choice of length-scales present in
the flow geometry.Comment: 4 pages, 4 figure
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