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%A A. Stefanie Reinhold
%A J. Ignacio Sanguinetti-Scheck
%A K. Hartmann
%A M. Brecht
%T Behavioral and neural correlates of hide-and-seek in rats
%J Science
%V 365
%N 6458
%P 1180-1183
%M SEP
%D 2019
%K jrnl, c2019, c201x, c20xx, zz0421, animal behaviour, rat, rats,
hide and seek, play, fun, game, games
%X "... We played hide-and-seek, an elaborate role-play game, with rats. We did
not offer food rewards but engaged in playful interactions after finding or
being found. Rats quickly learned the game & learned to alternate between
hiding v. seeking roles. They guided seeking by vision & memories of past
hiding locations & emitted game event-specific vocalizations. When hiding,
rats vocalized infrequently & they preferred opaque over transparent hiding
enclosures, a preference not observed during seeking. Neuronal recordings
revealed intense prefrontal cortex activity that varied with game events &
trial types ('hide' versus 'seek') & might instruct role play. The elaborate
cognitive capacities for hide-and-seek in rats suggest that this game might
be evolutionarily old."
-- [doi:10.1126/science.aax4705]['21].
(Surely an IgNobel prize contender?)
%A B. Vernot
%A et al
%T Unearthing Neanderthal population history using nuclear and mitochondrial
DNA from cave sediments
%J Science
%M APR
%D 2021
%K jrnl, MolBio, c2021, c202x, c20xx, zz0421, ancient DNA, Neanderthal, human,
history, cave, sediment, Spain
%X "... developed methods for the enrichment & analysis of nuclear DNA from
sediments, & applied them to cave deposits in W.Europe & S.Siberia dated to
between ~ 200,000 & 50,000 y. ago. We detect a population replacement in
N.Spain ~100,000 y. ago, accompanied by a turnover of mitochondrial DNA. We
also identify two radiation events in Neanderthal history during the early
part of the Late Pleistocene. ..."
-- [doi:10.1126/science.abf1667]['21].
%A J. Pablo Bonilla Ataides
%A D. K. Tuckett
%A S. D. Bartlett
%A S. T. Flammia
%A B. J. Brown
%T The XZZX surface code
%J Nat. Comms.
%V 12
%N 2172
%M APR
%D 2021
%K jrnl, c2021, c202x, c20xx, zz0421, quantum computing, fault tolerant, qubit,
XZZX surface code
%X "Performing large calculations with a quantum computer will likely require a
fault-tolerant architecture based on quantum error-correcting codes. ... we
show that a variant of the surface code - the XZZX code - offers remarkable
performance for fault-tolerant q.comp'n. The error threshold of this code
matches what can be achieved with random codes (hashing) for every
single-qubit Pauli noise channel; it is the first explicit code shown to have
this universal property. We present numerical evidence that the threshold
even exceeds this hashing bound for an experimentally relevant range of noise
parameters. ... show that it is possible to maintain all of these advantages
when we perform fault-tolerant quantum computation.
-- [doi:10.1038/s41467-021-22274-1]['21].
Also see [abc]['4/2021].
%A D. Deutsch
%A C. Marletto
%T Constructor theory of information
%J arXiv
%M MAY
%D 2014
%K TR, c2014, c201x, c20xx, zz0421, quantum physics, classical, information,
theory, qubits
%X "We present a theory of information expressed solely in terms of which
transformations of physical systems are possible & which are impossible -
i.e. in constructor-theoretic terms. Although it includes conjectured laws of
physics that are directly about info., indep. of the details of particular
physical instantiations, it does not regard info. as an a priori
mathematical or logical concept, but as something whose nature & properties
are determined by the laws of physics alone. It does not suffer from the
circularity at the foundations of existing info.theory (namely that info. &
distinguishability are each defined in terms of the other). It explains the
relationship between classical & quantum info., & reveals the single,
constructor-theoretic property underlying the most distinctive phenomena
assoc. with the latter, inc. the lack of in-principle distinguishability of
some states, the impossibility of cloning, the existence of pairs of
variables that cannot simultaneously have sharp values, the fact that
measurement processes can be both deterministic & unpredictable, the
irreducible perturbation caused by measurement, & entanglement (locally
inaccessible information).
-- 1405.5563@[arXiv]['21].
Also see [www]['21] & [www]['21].
[Also search for: Marletto].
%A C. Marletto
%T Constructor theory of life
%J arXiv
%M JUL
%D 2014
%K TR, c2014, c201x, c20xx, zz0421, life, reproduction, replication, replicator,
natural selection, Darwinian, evolution
%X "Neo-Darwinian evol. theory explains how the appearance of purposive design
in the sophisticated adaptations of living organisms can have come about
without their intentionally being designed. The explanation relies crucially
on the possibility of certain physical processes: mainly, gene replication &
natural selection. ... I show that for those processes to be possible without
the design of biological adaptations being encoded in the laws of physics,
those laws must have certain other properties. The theory of what these
properties are is not part of evolution theory proper, & has not been
developed, yet without it the neo-Darwinian theory does not fully achieve its
purpose of explaining the appearance of design. To this end I apply
Constructor Theory's new mode of explanation to provide an exact formulation
of the appearance of design, of no-design laws, & of the logic of
self-reproduction & natural selection, within fundamental physics. I conclude
that self-reproduction, replication & natural selection are possible under
no-design laws, the only non-trivial condition being that they allow digital
information to be physically instantiated. This has an exact characterisation
in the constructor theory of information. I also show that under no-design
laws an accurate replicator requires the existence of a 'vehicle'
constituting, together with the replicator, a self-reproducer."
-- 1407.0681@[arXiv]['21].
[Also search for: Marletto constructor]
%A A. Vezzosi
%A A. Mortberg
%A A. Abel
%T Cubical Agda: A dependently typed programming language with univalence and
higher inductive types
%J JFP
%M APR
%D 2021
%K jrnl, FP, JFP, c2021, c202x, c20xx, zz0421, type, dependent, dependant,
types, system, Agda, functional programming language
%X "... Cubical type theory provides a solution by giving computational meaning
to Homotopy Type Theory and Univalent Foundations, in particular to the
univalence axiom and higher inductive types (HITs). ... describes an ext'n of
the dependently typed functional [PL] Agda with cubical primitives, making it
into a full-blown proof assistant with native support for univalence and ..."
-- [doi:10.1017/S0956796821000034]['21].
[Also search for: Agda].
%A S. Bates
%A T. Hastie
%A R. Tibshirani
%T Cross-validation: what does it estimate and how well does it do it?
%J arXiv
%M APR
%D 2021
%K TR, c2021, c202x, c20xx, zz0421, stats, cross validation, estimate, accuracy,
variance, bootstrap, splitting, model, confidence interval, CI, stats
%X "... one would like to think that cross-validation estimates the prediction
error for the model at hand, fit to the training data. We prove that this is
not the case for the linear model fit by ordinary least squares; rather it
estimates the avg. prediction error of models fit on other unseen training
sets drawn from the same pop'n. We further show that this phenomenon occurs
for most popular ests. of prediction error, inc. data splitting,
bootstrapping, & Mallow's Cp. Next, the std confidence intervals for
prediction error derived from cross-validation may have coverage far below
the desired level. Because each data point is used for both training &
testing, there are correlations among the measured accuracies for each fold,
& so the usual est. of variance is too small. We introduce a nested
cross-validation scheme to est. this variance more accurately, & show
empirically that this modification leads to intervals with approx. correct
coverage ... Lastly, our analysis also shows that when producing confidence
intervals for prediction accuracy with simple data splitting, one should not
re-fit the model on the combined data, since this invalidates the CIs."
-- 2104.00673@[arXiv]['21]. [50 refs. via AK]
%A P. Bloem
%T Finding motifs in knowledge graphs using compression
%J arXiv
%M APR
%D 2021
%K TR, c2021, c202x, c20xx, zz0421, maths, graph, network, motif, compress
%X "We introduce a method to find network motifs in knowledge graphs. Network
motifs are useful patterns or meaningful subunits of the g. that recur
frequently. We extend the common definition of a n/wk motif to coincide with
a basic g.pattern. We introduce an approach, inspired by recent work for
simple gs., to induce these from a given knowledge g., & show that the motifs
found reflect the basic structure of the g.. Specifically, we show that in
random gs., no motifs are found, & that when we insert a motif artificially,
it can be detected. Finally, we show the results of motif induction on three
real-world knowledge gs.."
-- 2104.08163@[arXiv]['21].
[Also search for: graph motif compress].