158 research outputs found
On the enumeration of tanglegrams and tangled chains
Tanglegrams are a special class of graphs appearing in applications
concerning cospeciation and coevolution in biology and computer science. They
are formed by identifying the leaves of two rooted binary trees. We give an
explicit formula to count the number of distinct binary rooted tanglegrams with
matched vertices, along with a simple asymptotic formula and an algorithm
for choosing a tanglegram uniformly at random. The enumeration formula is then
extended to count the number of tangled chains of binary trees of any length.
This includes a new formula for the number of binary trees with leaves. We
also give a conjecture for the expected number of cherries in a large randomly
chosen binary tree and an extension of this conjecture to other types of trees
Oxytocin improves synchronisation in leader-follower interaction
The neuropeptide oxytocin has been shown to affect social interaction. Meanwhile, the underlying mechanism remains highly debated. Using an interpersonal finger-tapping paradigm, we investigated whether oxytocin affects the ability to synchronise with and adapt to the behaviour of others. Dyads received either oxytocin or a non-active placebo, intranasally. We show that in conditions where one dyad-member was tapping to another unresponsive dyad-member – i.e. one was following another who was leading/self-pacing – dyads given oxytocin were more synchronised than dyads given placebo. However, there was no effect when following a regular metronome or when both tappers were mutually adapting to each other. Furthermore, relative to their self-paced tapping partners, oxytocin followers were less variable than placebo followers. Our data suggests that oxytocin improves synchronisation to an unresponsive partner’s behaviour through a reduction in tapping-variability. Hence, oxytocin may facilitate social interaction by enhancing sensorimotor predictions supporting interpersonal synchronisation. The study thus provides novel perspectives on how neurobiological processes relate to socio-psychological behaviour and contributes to the growing evidence that synchronisation and prediction are central to social cognition
Manin matrices and Talalaev's formula
We study special class of matrices with noncommutative entries and
demonstrate their various applications in integrable systems theory. They
appeared in Yu. Manin's works in 87-92 as linear homomorphisms between
polynomial rings; more explicitly they read: 1) elements in the same column
commute; 2) commutators of the cross terms are equal: (e.g. ). We claim
that such matrices behave almost as well as matrices with commutative elements.
Namely theorems of linear algebra (e.g., a natural definition of the
determinant, the Cayley-Hamilton theorem, the Newton identities and so on and
so forth) holds true for them.
On the other hand, we remark that such matrices are somewhat ubiquitous in
the theory of quantum integrability. For instance, Manin matrices (and their
q-analogs) include matrices satisfying the Yang-Baxter relation "RTT=TTR" and
the so--called Cartier-Foata matrices. Also, they enter Talalaev's
hep-th/0404153 remarkable formulas: ,
det(1-e^{-\p}T_{Yangian}(z)) for the "quantum spectral curve", etc. We show
that theorems of linear algebra, after being established for such matrices,
have various applications to quantum integrable systems and Lie algebras, e.g
in the construction of new generators in (and, in general,
in the construction of quantum conservation laws), in the
Knizhnik-Zamolodchikov equation, and in the problem of Wick ordering. We also
discuss applications to the separation of variables problem, new Capelli
identities and the Langlands correspondence.Comment: 40 pages, V2: exposition reorganized, some proofs added, misprints
e.g. in Newton id-s fixed, normal ordering convention turned to standard one,
refs. adde
Effect of Protein Kinase Cβ Inhibition on Renal Hemodynamic Function and Urinary Biomarkers in Humans With Type 1 Diabetes: A Pilot Study
OBJECTIVE—The aim of this study was to examine the effect of protein kinase Cβ inhibition with ruboxistaurin on renal hemodynamic function and urinary biomarkers (monocyte chemoattractant protein-1 [MCP-1] and epidermal growth factor) in renin angiotensin system blockade-treated type 1 diabetic subjects
The human diabetes proteome project (HDPP): The 2014 update
Diabetes is an increasing worldwide problem leading to major associated health issues and increased health care costs. In 2012, 9.3% of the American population was affected by diabetes, according to the American Diabetes Association, with 1.7 million of new cases since during the year (www.diabetes.org). Proteome initiatives can provide a deeper understanding of the biology of this disease and help develop more effective treatments. The collaborative effort of the Human Diabetes Proteome Project (HDPP) brings together a wide variety of complementary resources to increase the existing knowledge about both type 1 and type 2 diabetes and their related complications. The goals are to identify proteins and protein isoforms associated with the pathology and to characterize underlying disease-related pathways and mechanisms. Moreover, a considerable effort is being made on data integration and network biology. Sharing these data with the scientific community will be an important part of the consortium. Here we report on: the content of the HDPP session held at the 12th HUPO meeting in Yokohama; recent achievements of the consortium; discussions of several HDPP workshops; as well as future HDPP directions as discussed at the 13th HUPO congress in Madrid, with a special attention given to the lists of prioritized, diabetes-related proteins and the proteomic means to study them.</p
Cooperation for public goods under uncertainty
Everyone wants clean air, peace and other public goods but is tempted to
freeride on others' efforts. The usual way out of this dilemma is to impose
norms, maintain reputations and incentivize individuals to contribute. In
situations of high uncertainty, however, such as confrontations of protesters
with a dictatorial regime, the usual measures are not feasible, but cooperation
can be achieved nevertheless. We use an Ising model with asymmetric spins that
represent cooperation and defection to show numerically how public goods can be
realized. Under uncertainty, people use the heuristic of conformity. The
turmoil of a confrontation causes some individuals to cooperate accidentally,
and at a critical level of turmoil, they entail a cascade of cooperation. This
critical level is much lower in small networks
The Smartphone Brain Scanner: A Portable Real-Time Neuroimaging System
Combining low cost wireless EEG sensors with smartphones offers novel
opportunities for mobile brain imaging in an everyday context. We present a
framework for building multi-platform, portable EEG applications with real-time
3D source reconstruction. The system - Smartphone Brain Scanner - combines an
off-the-shelf neuroheadset or EEG cap with a smartphone or tablet, and as such
represents the first fully mobile system for real-time 3D EEG imaging. We
discuss the benefits and challenges of a fully portable system, including
technical limitations as well as real-time reconstruction of 3D images of brain
activity. We present examples of the brain activity captured in a simple
experiment involving imagined finger tapping, showing that the acquired signal
in a relevant brain region is similar to that obtained with standard EEG lab
equipment. Although the quality of the signal in a mobile solution using a
off-the-shelf consumer neuroheadset is lower compared to that obtained using
high density standard EEG equipment, we propose that mobile application
development may offset the disadvantages and provide completely new
opportunities for neuroimaging in natural settings
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