2,020 research outputs found
Don\u27t Be Cruel (Anymore): A Look at the Animal Cruelty Regimes of the United States and Brazil with a Call for a New Animal Welfare Agency
In the United States and around the world, animals exploited for human use suffer cruel and needless harm. The group bearing the brunt of this exploitation— agricultural animals—is routinely exempted from the largely ineffective and rarely enforced animal welfare and anti-cruelty regulations that exist today. This Article offers a comparative analysis of the agricultural animal welfare regimes of two countries with globally significant presence in the agriculture industry: the United States and Brazil. Even though the two countries approach agricultural animal welfare differently, they arrive at the same outcome: institutionalized indifference to animal suffering. To remedy the current regulatory structure, this Article proposes the creation of an independent federal agency— The Animal Welfare Agency (“AWA”)—to regulate the safety and welfare of all animals, including those used in agriculture. The AWA could significantly reduce systemic animal cruelty in both the United States and Brazil and represent an important step toward inserting morality and ethics into our relationships with animals
On statistically stationary homogeneous shear turbulence
A statistically stationary turbulence with a mean shear gradient is realized
in a flow driven by suitable body forces. The flow domain is periodic in
downstream and spanwise directions and bounded by stress free surfaces in the
normal direction. Except for small layers near the surfaces the flow is
homogeneous. The fluctuations in turbulent energy are less violent than in the
simulations using remeshing, but the anisotropy on small scales as measured by
the skewness of derivatives is similar and decays weakly with increasing
Reynolds number.Comment: 4 pages, 5 figures (Figs. 3 and 4 as external JPG-Files
Approach to ergodicity in quantum wave functions
According to theorems of Shnirelman and followers, in the semiclassical limit
the quantum wavefunctions of classically ergodic systems tend to the
microcanonical density on the energy shell. We here develop a semiclassical
theory that relates the rate of approach to the decay of certain classical
fluctuations. For uniformly hyperbolic systems we find that the variance of the
quantum matrix elements is proportional to the variance of the integral of the
associated classical operator over trajectory segments of length , and
inversely proportional to , where is the Heisenberg
time, being the mean density of states. Since for these systems the
classical variance increases linearly with , the variance of the matrix
elements decays like . For non-hyperbolic systems, like Hamiltonians
with a mixed phase space and the stadium billiard, our results predict a slower
decay due to sticking in marginally unstable regions. Numerical computations
supporting these conclusions are presented for the bakers map and the hydrogen
atom in a magnetic field.Comment: 11 pages postscript and 4 figures in two files, tar-compressed and
uuencoded using uufiles, to appear in Phys Rev E. For related papers, see
http://www.icbm.uni-oldenburg.de/icbm/kosy/ag.htm
Statistical analysis of coherent structures in transitional pipe flow
Numerical and experimental studies of transitional pipe flow have shown the
prevalence of coherent flow structures that are dominated by downstream
vortices. They attract special attention because they contribute predominantly
to the increase of the Reynolds stresses in turbulent flow. In the present
study we introduce a convenient detector for these coherent states, calculate
the fraction of time the structures appear in the flow, and present a Markov
model for the transition between the structures. The fraction of states that
show vortical structures exceeds 24% for a Reynolds number of about Re=2200,
and it decreases to about 20% for Re=2500. The Markov model for the transition
between these states is in good agreement with the observed fraction of states,
and in reasonable agreement with the prediction for their persistence. It
provides insight into dominant qualitative changes of the flow when increasing
the Reynolds number.Comment: 11 pages, 26 (sub)figure
Climatological aspects of the extreme European rainfall of August 2002 and a trajectory method for estimating the associated evaporative source regions
International audienceDuring the first half of August 2002, a sequence of extreme precipitation episodes affected many regions of central and southern Europe, culminating in one of the most severe flooding events ever experienced along sections of the river Elbe and its tributaries. In this paper, the synoptic meteorological situation during the primary flooding event, 11-13 August 2002, and its recent background is illustrated and discussed. Then, backward trajectory modelling of water vapour transport is employed to determine the sources and transport pathways of the moisture which rained out during the event. The Lagrangian trajectory model FLEXTRA is used together with high resolution operational meteorological analyses from the ECMWF to track a very large number of trajectories, initialized in a dense three-dimensional grid array over the extreme rainfall region. Specific humidity changes along each trajectory are mapped out to yield source-receptor relationships between evaporation and subsequent precipitation for the event. Regions of significant surface evaporation of moisture which later rained out were determined to be parts of the Aegean and Ligurian Seas during the initial stages of the event, while strong evaporation from eastern European land surfaces and from the Black Sea became dominant later on. The method also provides precipitation estimates based solely on specific humidity changes along Lagrangian airmass trajectories, which can be compared to ECMWF model forecast precipitation estimates
Chaos and Correspondence in Classical and Quantum Hamiltonian Ratchets: A Heisenberg Approach
Previous work [Gong and Brumer, Phys. Rev. Lett., 97, 240602 (2006)]
motivates this study as to how asymmetry-driven quantum ratchet effects can
persist despite a corresponding fully chaotic classical phase space. A simple
perspective of ratchet dynamics, based on the Heisenberg picture, is
introduced. We show that ratchet effects are in principle of common origin in
classical and quantum mechanics, though full chaos suppresses these effects in
the former but not necessarily the latter. The relationship between ratchet
effects and coherent dynamical control is noted.Comment: 21 pages, 7 figures, to appear in Phys. Rev.
Clustering dynamics of Lagrangian tracers in free-surface flows
We study the formation of clusters of passive Lagrangian tracers in a
non-smooth turbulent flow in a flat free-slip surface as a model for particle
dynamics on free surfaces. Single particle and pair dispersion show different
behavior for short and large times: on short times particles cluster
exponentially rapidly until patches of the size of the divergence correlation
length are depleted; on larger times the pair dispersion is dominated by almost
ballistic hopping between clusters. We also find that the distribution of
particle density is close to algebraic and can trace this back to the
exponential distribution of the divergence field of the surface flow.Comment: 5 pages, 5 Postscript figure
Mechanisms of deep brain stimulation for obsessive compulsive disorder: effects upon cells and circuits
Deep brain stimulation (DBS) has emerged as a safe, effective, and reversible treatment for a number of movement disorders. This has prompted investigation of its use for other applications including psychiatric disorders. In recent years, DBS has been introduced for the treatment of obsessive compulsive disorder (OCD), which is characterized by recurrent unwanted thoughts or ideas (obsessions) and repetitive behaviors or mental acts performed in order to relieve these obsessions (compulsions). Abnormal activity in cortico-striato-thalamo-cortical (CSTC) circuits including the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), ventral striatum, and mediodorsal (MD) thalamus has been implicated in OCD. To this end a number of DBS targets including the anterior limb of the internal capsule (ALIC), ventral capsule/ventral striatum (VC/VS), ventral caudate nucleus, subthalamic nucleus (STN), and nucleus accumbens (NAc) have been investigated for the treatment of OCD. Despite its efficacy and widespread use in movement disorders, the mechanism of DBS is not fully understood, especially as it relates to psychiatric disorders. While initially thought to create a functional lesion akin to ablative procedures, it is increasingly clear that DBS may induce clinical benefit through activation of axonal fibers spanning the CSTC circuits, alteration of oscillatory activity within this network, and/or release of critical neurotransmitters. In this article we review how the use of DBS for OCD informs our understanding of both the mechanisms of DBS and the circuitry of OCD. We review the literature on DBS for OCD and discuss potential mechanisms of action at the neuronal level as well as the broader circuit level
Providing Services to Family Caregivers at Home: Challenges and Recommendations for Health and Human Service Professions
The home represents a relatively new arena for practice for most service providers, especially those working with families of persons with dementia. This article describes four key factors to consider when working with caregivers of persons with dementia in their homes. The authors also discuss seven common challenges of service provision in the home and recommend strategies for addressing these challenges
Travelling waves in pipe flow
A family of three-dimensional travelling waves for flow through a pipe of
circular cross section is identified. The travelling waves are dominated by
pairs of downstream vortices and streaks. They originate in saddle-node
bifurcations at Reynolds numbers as low as 1250. All states are immediately
unstable. Their dynamical significance is that they provide a skeleton for the
formation of a chaotic saddle that can explain the intermittent transition to
turbulence and the sensitive dependence on initial conditions in this shear
flow.Comment: 4 pages, 5 figure
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