2,059 research outputs found
Classification under Streaming Emerging New Classes: A Solution using Completely Random Trees
This paper investigates an important problem in stream mining, i.e.,
classification under streaming emerging new classes or SENC. The common
approach is to treat it as a classification problem and solve it using either a
supervised learner or a semi-supervised learner. We propose an alternative
approach by using unsupervised learning as the basis to solve this problem. The
SENC problem can be decomposed into three sub problems: detecting emerging new
classes, classifying for known classes, and updating models to enable
classification of instances of the new class and detection of more emerging new
classes. The proposed method employs completely random trees which have been
shown to work well in unsupervised learning and supervised learning
independently in the literature. This is the first time, as far as we know,
that completely random trees are used as a single common core to solve all
three sub problems: unsupervised learning, supervised learning and model update
in data streams. We show that the proposed unsupervised-learning-focused method
often achieves significantly better outcomes than existing
classification-focused methods
Foreword
Proteins that contain long disordered regions are prevalent in the proteome and frequently associated with diseases. However, the mechanisms by which such intrinsically disordered proteins (IDPs) recognize their targets are not well understood. Here, we report the first experimental investigation of the interaction kinetics of the nuclear co-activator binding domain of CREB-binding protein and the activation domain from the p160 transcriptional co-activator for thyroid hormone and retinoid receptors. Both protein domains are intrinsically disordered in the free state and synergistically fold upon binding each other. Using the stopped-flow technique, we found that the binding reaction is fast, with an association rate constant of 3 x 10(7) M-1 s(-1) at 277 K. Mutation of a conserved buried intermolecular salt bridge showed that electrostatics govern the rapid association. Furthermore, upon mutation of the salt bridge or at high salt concentration, an additional kinetic phase was detected (similar to 20 and similar to 40 s(-1), respectively, at 277 K), suggesting that the salt bridge may steer formation of the productive bimolecular complex in an intramolecular step. Finally, we directly measured slow kinetics for the IDP domains (similar to 1 s(-1) at 277 K) related to conformational transitions upon binding. Together, the experiments demonstrate that the interaction involves several steps and accumulation of intermediate states. Our data are consistent with an induced fit mechanism, in agreement with previous simulations. We propose that the slow transitions may be a consequence of the multipartner interactions of IDPs
Entanglement R\'enyi -entropy
We study the entanglement R\'{e}nyi -entropy (ERE) as the
measure of entanglement. Instead of a single quantity in standard entanglement
quantification for a quantum state by using the von Neumann entropy for the
well-accepted entanglement of formation (EoF), the ERE gives a
continuous spectrum parametrized by variable as the entanglement
measure, and it reduces to the standard EoF in the special case . The ERE provides more information in entanglement
quantification, and can be used such as in determining the convertibility of
entangled states by local operations and classical communication. A series of
new results are obtained: (i) we can show that ERE of two states,
which can be mixed or pure, may be incomparable, in contrast to the fact that
there always exists an order for EoF of two states; (ii) similar as the case of
EoF, we study in a fully analytical way the ERE for arbitrary
two-qubit states, the Werner states and isotropic states in general
d-dimension; (iii) we provide a proof of the previous conjecture for the
analytical functional form of EoF of isotropic states in arbitrary d-dimension.Comment: 11 pages, 4 figure
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