6,334 research outputs found
Who Benefits from Child Benefit?
Governments, over much of the developed world, make significant financial transfers to parents with dependent children. For example, in the US the recently introduced Child Tax Credit (CTC), which goes to almost all children, costs almost 25 a week on each of about 8 million children – about 1% of GNP. The typical rationale given for these transfers is that they are good for our children and here we investigate the effect of such transfers on household spending patterns. The UK is an excellent laboratory to address this issue because such transfers, known as Child Benefit (CB) have been simple lump sum universal payments for a continuous period of more than 20 years. We do indeed find that CB is spent differently from other income – paradoxically, it appears to be spent disproportionately on adult-assignable goods. In fact we estimate that as much as half of a marginal pound of CB is spent on alcohol. We resolve this puzzle by showing that the effect is confined to unanticipated variation in CB so we infer that parents are sufficiently altruistic towards their children that they completely insure them against shocks.altruism, child poverty, intra-household transfers
Intrinsic random walks and sub-Laplacians in sub-Riemannian geometry
On a sub-Riemannian manifold we define two type of Laplacians. The
\emph{macroscopic Laplacian} , as the divergence of the
horizontal gradient, once a volume is fixed, and the \emph{microscopic
Laplacian}, as the operator associated with a sequence of geodesic random
walks. We consider a general class of random walks, where \emph{all}
sub-Riemannian geodesics are taken in account. This operator depends only on
the choice of a complement to the sub-Riemannian distribution, and
is denoted .
We address the problem of equivalence of the two operators. This problem is
interesting since, on equiregular sub-Riemannian manifolds, there is always an
intrinsic volume (e.g. Popp's one ) but not a canonical choice of
complement. The result depends heavily on the type of structure under
investigation. On contact structures, for every volume , there exists a
unique complement such that . On Carnot groups, if
is the Haar volume, then there always exists a complement such that
. However this complement is not unique in general. For
quasi-contact structures, in general, for any choice of
. In particular, is not symmetric w.r.t. Popp's measure. This is
surprising especially in dimension 4 where, in a suitable sense, is
the unique intrinsic macroscopic Laplacian.
A crucial notion that we introduce here is the N-intrinsic volume, i.e. a
volume that depends only on the set of parameters of the nilpotent
approximation. When the nilpotent approximation does not depend on the point, a
N-intrinsic volume is unique up to a scaling by a constant and the
corresponding N-intrinsic sub-Laplacian is unique. This is what happens for
dimension smaller or equal than 4, and in particular in the 4-dimensional
quasi-contact structure mentioned above.Comment: 42 pages, 1 figure. v2: minor revisions; v3: minor typos corrected;
v4: final version, to appear on Advances in Mathematic
How to Host a Data Competition: Statistical Advice for Design and Analysis of a Data Competition
Data competitions rely on real-time leaderboards to rank competitor entries
and stimulate algorithm improvement. While such competitions have become quite
popular and prevalent, particularly in supervised learning formats, their
implementations by the host are highly variable. Without careful planning, a
supervised learning competition is vulnerable to overfitting, where the winning
solutions are so closely tuned to the particular set of provided data that they
cannot generalize to the underlying problem of interest to the host. This paper
outlines some important considerations for strategically designing relevant and
informative data sets to maximize the learning outcome from hosting a
competition based on our experience. It also describes a post-competition
analysis that enables robust and efficient assessment of the strengths and
weaknesses of solutions from different competitors, as well as greater
understanding of the regions of the input space that are well-solved. The
post-competition analysis, which complements the leaderboard, uses exploratory
data analysis and generalized linear models (GLMs). The GLMs not only expand
the range of results we can explore, they also provide more detailed analysis
of individual sub-questions including similarities and differences between
algorithms across different types of scenarios, universally easy or hard
regions of the input space, and different learning objectives. When coupled
with a strategically planned data generation approach, the methods provide
richer and more informative summaries to enhance the interpretation of results
beyond just the rankings on the leaderboard. The methods are illustrated with a
recently completed competition to evaluate algorithms capable of detecting,
identifying, and locating radioactive materials in an urban environment.Comment: 36 page
The cultural epigenetics of psychopathology: The missing heritability of complex diseases found?
We extend a cognitive paradigm for gene expression based on the asymptotic limit theorems of information theory to the epigenetic epidemiology of mental disorders. In particular, we recognize the fundamental role culture plays in human biology, another heritage mechanism parallel to, and interacting with, the more familiar genetic and epigenetic systems. We do this via a model through which culture acts as another tunable epigenetic catalyst that both directs developmental trajectories, and becomes convoluted with individual ontology, via a mutually-interacting crosstalk mediated by a social interaction that is itself culturally driven. We call for the incorporation of embedding culture as an essential component of the epigenetic regulation of human mental development and its dysfunctions, bringing what is perhaps the central reality of human biology into the center of biological psychiatry. Current US work on gene-environment interactions in psychiatry must be extended to a model of gene-environment-culture interaction to avoid becoming victim of an extreme American individualism that threatens to create paradigms particular to that culture and that are, indeed, peculiar in the context of the world's cultures. The cultural and epigenetic systems of heritage may well provide the 'missing' heritability of complex diseases now under so much intense discussion
Roman roads: The hierarchical endosymbiosis of cognitive modules
Serial endosymbiosis theory provides a unifying paradigm for examining the interaction of cognitive modules at vastly different scales of biological, social, and cultural organization. A trivial but not unimportant model associates a dual information source with a broad class of cognitive processes, and punctuated phenomena akin to phase transitions in physical systems, and associated coevolutionary processes, emerge as consequences of the homology between information source uncertainty and free energy density. The dynamics, including patterns of punctuation similar to ecosystem resilience transitions, are large dominated by the availability of 'Roman roads' constituting channels for the transmission of information between modules
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