12,297 research outputs found
U.S.-CANADIAN DAIRY TRADE TENSIONS: THE NATURE AND EFFECTS OF CANADIAN DAIRY POLICY
Agricultural and Food Policy, International Relations/Trade,
Enhancement of mobilities in a pinned multidomain crystal
Mobility properties inside and around degenerate domains of an elastic
lattice partially pinned on a square array of traps are explored by means of a
fully controllable model system of macroscopic particles. We focus on the
different configurations obtained for filling ratios equal to 1 or 2 when the
pinning strength is lowered. These theoretically expected but never observed
configurations are degenerated, which implies the existence of a multidomain
crystal. We show that the distinction between trapped and untrapped particles
that is made in the case of strong pinning is not relevant for such a weaker
pinning. Indeed, one ought to distinguish between particles inside or around
the domains associated to positional degeneracies. The possible consequences on
the depinning dynamics of the lattice are discussed.Comment: 7 pages, 10 figures Version 2 : longer versio
Single File Diffusion enhancement in a fluctuating modulated 1D channel
We show that the diffusion of a single file of particles moving in a
fluctuating modulated 1D channel is enhanced with respect to the one in a bald
pipe. This effect, induced by the fluctuations of the modulation, is favored by
the incommensurability between the channel potential modulation and the moving
file periodicity. This phenomenon could be of importance in order to optimize
the critical current in superconductors, in particular in the case where mobile
vortices move in 1D channels designed by adapted patterns of pinning sites.Comment: 4 pages, 4 figure
Partisan Conflict and Income Inequality in the United States: A Nonparametric Causality-in-Quantiles Approach
This paper examines the predictive power of a partisan conflict on income inequality. Our study contributes to the existing literature by using the newly introduced nonparametric causality-in-quantile testing approach to examine how political polarization in the United States affects several measures of income inequality and distribution overtime. The study uses annual time-series data between the periods 1917–2013. We find evidence in support of a dynamic causal relationship between partisan conflict and income inequality, except at the upper end of the quantiles. Our empirical findings suggest that a reduction in partisan conflict will lead to a reduction in our measures of income inequality, but this requires that inequality is not exceptionally high
Determination of the interactions in confined macroscopic Wigner islands: theory and experiments
Macroscopic Wigner islands present an interesting complementary approach to
explore the properties of two-dimensional confined particles systems. In this
work, we characterize theoretically and experimentally the interaction between
their basic components, viz., conducting spheres lying on the bottom electrode
of a plane condenser. We show that the interaction energy can be approximately
described by a decaying exponential as well as by a modified Bessel function of
the second kind. In particular, this implies that the interactions in this
system, whose characteristics are easily controllable, are the same as those
between vortices in type-II superconductors.Comment: 8 pages, 8 figure
Estimating hospital costs of catheter‐associated urinary tract infection
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/100140/1/jhm2079.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/100140/2/jhm2079-sup-0002-suppinfo.pd
The evolution of sperm morphometry in pheasants
Postcopulatory sexual selection is thought to be a potent evolutionary force driving the
diversification of sperm shape and function across species. In birds, insemination and
fertilisation are separated in time and sperm storage increases the duration of sperm
female interaction and hence the opportunity for sperm competition and cryptic female
choice. We performed a comparative study of 24 pheasant species (Phasianidae,
Galliformes) to establish the relative importance of sperm competition and the duration of
sperm storage for the evolution of sperm morphometry (i.e. size of different sperm traits).
We found that sperm size traits were negatively associated with the duration of sperm
storage but were independent of the risk of sperm competition estimated from relative
testis mass. Our study emphasises the importance of female reproductive biology for the
evolution of sperm morphometry particularly in sperm storing taxa
Energy Balance in the Solar Transition Region. IV. Hydrogen and Helium Mass Flows With Diffusion
In this paper we have extended our previous modeling of energy balance in the
chromosphere-corona transition region to cases with particle and mass flows.
The cases considered here are quasi-steady, and satisfy the momentum and energy
balance equations in the transition region. We include in all equations the
flow velocity terms and neglect the partial derivatives with respect to time.
We present a complete and physically consistent formulation and method for
solving the non-LTE and energy balance equations in these situations, including
both particle diffusion and flows of H and He. Our results show quantitatively
how mass flows affect the ionization and radiative losses of H and He, thereby
affecting the structure and extent of the transition region. Also, our
computations show that the H and He line profiles are greatly affected by
flows. We find that line shifts are much less important than the changes in
line intensity and central reversal due to the effects of flows. In this paper
we use fixed conditions at the base of the transition region and in the
chromosphere because our intent is to show the physical effects of flows and
not to match any particular observations. However, we note that the profiles we
compute can explain the range of observed high spectral and spatial resolution
Lyman alpha profiles from the quiet Sun. We suggest that dedicated modeling of
specific sequences of observations based on physically consistent methods like
those presented here will substantially improve our understanding of the energy
balance in the chromosphere and corona.Comment: 50 pages + 20 figures; submitted to ApJ 9/10/01; a version with
higher resolution figures is available at http://cfa-www.harvard.edu/~avrett
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Dissociating visuo-spatial and verbal working memory: It’s all in the features
Echoing many of the themes of the seminal work of Atkinson and Shiffrin (1968), this paper uses the Feature Model (Nairne, 1988, 1990; Neath & Nairne, 1995) to account for performance in working memory tasks. The Brooks verbal and visuo-spatial matrix tasks were performed alone, with articulatory suppression, or with a spatial suppression task; the results produced the expected dissociation. We used Approximate Bayesian Computation techniques to fit the Feature Model to the data and showed that the similarity-based interference process implemented in the model accounted for the data patterns well. We then fit the model to data from Guérard and Tremblay (2008); the latter study produced a double dissociation while calling upon more typical order reconstruction tasks. Again, the model performed well. The findings show that a double dissociation can be modelled without appealing to separate systems for verbal and visuo-spatial processing. The latter findings are significant as the Feature Model had not been used to model this type of dissociation before; importantly, this is also the first time the model is quantitatively fit to data. For the demonstration provided here, modularity was unnecessary if two assumptions were made: (1) the main difference between spatial and verbal working memory tasks is the features that are encoded; (2) secondary tasks selectively interfere with primary tasks to the extent that both tasks involve similar features. It is argued that a feature-based view is more parsimonious (see Morey, 2018) and offers flexibility in accounting for multiple benchmark effects in the field
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