2,755 research outputs found
BIOTECHNOLOGY REGULATIONS AND THE WTO
This paper examines the regulation of trade in genetically modified organisms (GMOs) by the World Trade Organization (WTO). Despite rapid adoption of GMOs by a few exporters, many importers have developed relatively restrictive procedures for pre-market approval of GMOs, and are introducing mandatory labeling. While exporters have yet to seek a ruling from the WTO on these regulations, a trade dispute over GMOs is likely to occur before too long. Exporting countries will likely argue that importing countries' regulations are too restrictive, given existing scientific knowledge of the safety of current GM crops, and that labeling of GM foods is unnecessary due to the fact that they are typically similar to their conventional counterparts. In response, importing countries will likely argue that existing scientific knowledge about GMOs is insufficient, and that a precautionary approach to approval is appropriate. In addition, importers will claim that labeling is necessary due to the fact that they are not equivalent to their conventional counterparts, and consumers have a right to choose whether or not consume such foods, be it for religious, ethical or other reasons. In the event a panel will have decide on whether GM and non-GM products are "like goods", whether adequate risk assessment was undertaken for any regulation introduced for health reasons, whether labels constitute the "least trade distorting" way of meeting legitimate objectives, and whether regulations imply discrimination among suppliers or in favor of domestic producers. Experience with the SPS and TBT Agreements has not been extensive enough to indicate how such a panel might rule. But one can also view the issue in broader trade policy terms, as a balance between market access obligations that need to be adjusted as domestic regulations on new technologies are developed. A possible solution is for importing countries with tough GM regulation and mandatory labeling to offer reciprocal increases in market access for non-GM foods in compensation for any losses of market access for GM foods. There is a question though of whether such "rebalancing" is actually practical, and it would certainly add to the costs of dispute settlement in the WTO, but it may be the only viable solution in the long run if the WTO is not to be dragged in to evaluating social and ethical bases for regulation of biotechnology.Biotechnology, regulation, trade, WTO, International Relations/Trade, Research and Development/Tech Change/Emerging Technologies,
Cross-correlation Weak Lensing of SDSS galaxy Clusters II: Cluster Density Profiles and the Mass--Richness Relation
We interpret and model the statistical weak lensing measurements around
130,000 groups and clusters of galaxies in the Sloan Digital Sky Survey
presented by Sheldon et al. 2007 (Paper I). We present non-parametric
inversions of the 2D shear profiles to the mean 3D cluster density and mass
profiles in bins of both optical richness and cluster i-band luminosity. We
correct the inferred 3D profiles for systematic effects, including non-linear
shear and the fact that cluster halos are not all precisely centered on their
brightest galaxies. We also model the measured cluster shear profile as a sum
of contributions from the brightest central galaxy, the cluster dark matter
halo, and neighboring halos. We infer the relations between mean cluster virial
mass and optical richness and luminosity over two orders of magnitude in
cluster mass; the virial mass at fixed richness or luminosity is determined
with a precision of 13% including both statistical and systematic errors. We
also constrain the halo concentration parameter and halo bias as a function of
cluster mass; both are in good agreement with predictions of LCDM models. The
methods employed here will be applicable to deeper, wide-area optical surveys
that aim to constrain the nature of the dark energy, such as the Dark Energy
Survey, the Large Synoptic Survey Telescope and space-based surveys
Education Leaders Perspectives on Social & Emotional Learning
This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu.This peer-reviewed series of issue briefs is designed to help people understand, connect and champion social and emotional learning in a variety of settings and from a variety of perspectives
Dynamical Confirmation of SDSS Weak Lensing Scaling Laws
Galaxy masses can be estimated by a variety of methods; each applicable in
different circumstances, and each suffering from different systematic
uncertainties. Confirmation of results obtained by one technique with analysis
by another is particularly important. Recent SDSS weak lensing measurements of
the projected-mass correlation function reveal a linear relation between galaxy
luminosities and the depth of their dark matter halos (measured on 260 \hinv
kpc scales). In this work we use an entirely independent dynamical method to
confirm these results. We begin by assembling a sample of 618 relatively
isolated host galaxies, surrounded by a total of 1225 substantially fainter
satellites. We observe the mean dynamical effect of these hosts on the motions
of their satellites by assembling velocity difference histograms. Dividing the
sample by host properties, we find significant variations in satellite velocity
dispersion with host luminosity. We quantify these variations using a simple
dynamical model, measuring \mtsd a dynamical mass within 260 \hinv kpc. The
appropriateness of this mass reconstruction is checked by conducting a similar
analysis within an N-body simulation. Comparison between the dynamical and
lensing mass-to-light scalings shows reasonable agreement, providing some
quantitative confirmation for the lensing results.Comment: 7 pages, 3 figures, accepted for publication in ApJ Letter
Cross-correlation Weak Lensing of SDSS Galaxy Clusters III: Mass-to-light Ratios
We present measurements of the excess mass-to-light ratio measured
aroundMaxBCG galaxy clusters observed in the SDSS. This red sequence cluster
sample includes objects from small groups with masses ranging from ~5x10^{12}
to ~10^{15} M_{sun}/h. Using cross-correlation weak lensing, we measure the
excess mass density profile above the universal mean \Delta \rho(r) = \rho(r) -
\bar{\rho} for clusters in bins of richness and optical luminosity. We also
measure the excess luminosity density \Delta l(r) = l(r) - \bar{l} measured in
the z=0.25 i-band. For both mass and light, we de-project the profiles to
produce 3D mass and light profiles over scales from 25 kpc/ to 22 Mpc/h. From
these profiles we calculate the cumulative excess mass M(r) and excess light
L(r) as a function of separation from the BCG. On small scales, where \rho(r)
>> \bar{\rho}, the integrated mass-to-light profile may be interpreted as the
cluster mass-to-light ratio. We find the M/L_{200}, the mass-to-light ratio
within r_{200}, scales with cluster mass as a power law with index 0.33+/-0.02.
On large scales, where \rho(r) ~ \bar{\rho}, the M/L approaches an asymptotic
value independent of cluster richness. For small groups, the mean M/L_{200} is
much smaller than the asymptotic value, while for large clusters it is
consistent with the asymptotic value. This asymptotic value should be
proportional to the mean mass-to-light ratio of the universe . We find
/b^2_{ml} = 362+/-54 h (statistical). There is additional uncertainty in
the overall calibration at the ~10% level. The parameter b_{ml} is primarily a
function of the bias of the L <~ L_* galaxies used as light tracers, and should
be of order unity. Multiplying by the luminosity density in the same bandpass
we find \Omega_m/b^2_{ml} = 0.02+/-0.03, independent of the Hubble parameter.Comment: Third paper in a series; v2.0 incorporates ApJ referee's suggestion
Studying Inter-Cluster Galaxy Filaments Through Stacking GMBCG Galaxy Cluster Pairs
We present a method to study the photometric properties of galaxies in
filaments by stacking the galaxy populations between pairs of galaxy clusters.
Using Sloan Digital Sky Survey data, this method can detect the inter-cluster
filament galaxy overdensity with a significance of out to
. Using this approach, we study the color and luminosity
distribution of filament galaxies as a function of redshift. Consistent with
expectation, filament galaxies are bimodal in their color distribution and
contain a larger blue galaxy population than clusters. Filament galaxies are
also generally fainter than cluster galaxies. More interestingly, the observed
filament population seems to show redshift evolution at : the blue
galaxy fraction has a trend to increase at higher redshift: a filament "Butcher
Oemler Effect". We test the dependence of the observed filament density on the
richness of the cluster pair: richer clusters are connected by higher density
filaments. We also test the spatial dependence of filament galaxy overdensity:
this quantity decreases when moving away from the inter-cluster axis between a
cluster pair. This method provides an economical way to probe the photometric
properties of filament galaxies and should prove useful for upcoming projects
like the Dark Energy Survey.Comment: Submitted to Ap
A psychology based approach for longitudinal development in cognitive robotics.
A major challenge in robotics is the ability to learn, from novel experiences, new behavior that is useful for achieving new goals and skills. Autonomous systems must be able to learn solely through the environment, thus ruling out a priori task knowledge, tuning, extensive training, or other forms of pre-programming. Learning must also be cumulative and incremental, as complex skills are built on top of primitive skills. Additionally, it must be driven by intrinsic motivation because formative experience is gained through autonomous activity, even in the absence of extrinsic goals or tasks. This paper presents an approach to these issues through robotic implementations inspired by the learning behavior of human infants. We describe an approach to developmental learning and present results from a demonstration of longitudinal development on an iCub humanoid robot. The results cover the rapid emergence of staged behavior, the role of constraints in development, the effect of bootstrapping between stages, and the use of a schema memory of experiential fragments in learning new skills. The context is a longitudinal experiment in which the robot advanced from uncontrolled motor babbling to skilled hand/eye integrated reaching and basic manipulation of objects. This approach offers promise for further fast and effective sensory-motor learning techniques for robotic learning
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