@misc{5421,
abstract = {Evolution occurs in populations of reproducing individuals. The structure of the population affects the outcome of the evolutionary process. Evolutionary graph theory is a powerful approach to study this phenomenon. There are two graphs. The interaction graph specifies who interacts with whom in the context of evolution. The replacement graph specifies who competes with whom for reproduction. The vertices of the two graphs are the same, and each vertex corresponds to an individual. A key quantity is the fixation probability of a new mutant. It is defined as the probability that a newly introduced mutant (on a single vertex) generates a lineage of offspring which eventually takes over the entire population of resident individuals. The basic computational questions are as follows: (i) the qualitative question asks whether the fixation probability is positive; and (ii) the quantitative approximation question asks for an approximation of the fixation probability. Our main results are: (1) We show that the qualitative question is NP-complete and the quantitative approximation question is #P-hard in the special case when the interaction and the replacement graphs coincide and even with the restriction that the resident individuals do not reproduce (which corresponds to an invading population taking over an empty structure). (2) We show that in general the qualitative question is PSPACE-complete and the quantitative approximation question is PSPACE-hard and can be solved in exponential time.},
author = {Chatterjee, Krishnendu and Ibsen-Jensen, Rasmus and Nowak, Martin},
issn = {2664-1690},
pages = {27},
publisher = {IST Austria},
title = {{The complexity of evolution on graphs}},
doi = {10.15479/AT:IST-2014-190-v2-2},
year = {2014},
}
@article{5813,
abstract = {We consider homogeneous Bose gas in a large cubic box with periodic boundary conditions, at zero temperature. We analyze its excitation spectrum in a certain kind of a mean-field infinite-volume limit. We prove that under appropriate conditions the excitation spectrum has the form predicted by the Bogoliubov approximation. Our result can be viewed as an extension of the result of Seiringer (Commun. Math. Phys.306:565–578, 2011) to large volumes.},
author = {Dereziński, Jan and Napiórkowski, Marcin M},
issn = {1424-0637},
journal = {Annales Henri Poincaré},
number = {12},
pages = {2409--2439},
publisher = {Springer Nature},
title = {{Excitation spectrum of interacting bosons in the Mean-Field Infinite-Volume limit}},
doi = {10.1007/s00023-013-0302-4},
volume = {15},
year = {2014},
}
@article{6126,
abstract = {Aerobic animals constantly monitor and adapt to changes in O2 levels. The molecular mechanisms involved in sensing O2 are, however, incompletely understood. Previous studies showed that a hexacoordinated globin called GLB-5 tunes the dynamic range of O2-sensing neurons in natural C. elegans isolates, but is defective in the N2 lab reference strain (McGrath et al., 2009; Persson et al., 2009). GLB-5 enables a sharp behavioral switch when O2 changes between 21 and 17%. Here, we show that GLB-5 also confers rapid behavioral and cellular recovery from exposure to hypoxia. Hypoxia reconfigures O2-evoked Ca2+ responses in the URX O2 sensors, and GLB-5 enables rapid recovery of these responses upon re-oxygenation. Forward genetic screens indicate that GLB-5's effects on O2 sensing require PDL-1, the C. elegans ortholog of mammalian PrBP/PDE6δ protein. In mammals, PDE6δ regulates the traffic and activity of prenylated proteins (Zhang et al., 2004; Norton et al., 2005). PDL-1 promotes localization of GCY-33 and GCY-35, atypical soluble guanylate cyclases that act as O2 sensors, to the dendritic endings of URX and BAG neurons, where they colocalize with GLB-5. Both GCY-33 and GCY-35 are predicted to be prenylated. Dendritic localization is not essential for GCY-35 to function as an O2 sensor, but disrupting pdl-1 alters the URX neuron's O2 response properties. Functional GLB-5 can restore dendritic localization of GCY-33 in pdl-1 mutants, suggesting GCY-33 and GLB-5 are in a complex. Our data suggest GLB-5 and the soluble guanylate cyclases operate in close proximity to sculpt O2 responses.},
author = {Gross, E. and Soltesz, Z. and Oda, S. and Zelmanovich, V. and Abergel, Z. and de Bono, Mario},
issn = {0270-6474},
journal = {Journal of Neuroscience},
number = {50},
pages = {16726--16738},
publisher = {Society for Neuroscience},
title = {{GLOBIN-5-dependent O2 responses are regulated by PDL-1/PrBP that targets prenylated soluble guanylate cyclases to dendritic endings}},
doi = {10.1523/jneurosci.5368-13.2014},
volume = {34},
year = {2014},
}
@article{6739,
abstract = {We explore the relationship between polar and RM codes and we describe a coding scheme which improves upon the performance of the standard polar code at practical block lengths. Our starting point is the experimental observation that RM codes have a smaller error probability than polar codes under MAP decoding. This motivates us to introduce a family of codes that “interpolates” between RM and polar codes, call this family C inter = {C α : α ∈ [0, 1j}, where C α|α=1 is the original polar code, and C α|α=0 is an RM code. Based on numerical observations, we remark that the error probability under MAP decoding is an increasing function of α. MAP decoding has in general exponential complexity, but empirically the performance of polar codes at finite block lengths is boosted by moving along the family Cinter even under low-complexity decoding schemes such as, for instance, belief propagation or successive cancellation list decoder. We demonstrate the performance gain via numerical simulations for transmission over the erasure channel as well as the Gaussian channel.},
author = {Mondelli, Marco and Hassani, Hamed and Urbanke, Rudiger},
issn = {0090-6778},
journal = {IEEE Transactions on Communications},
number = {9},
pages = {3084--3091},
publisher = {IEEE},
title = {{From polar to Reed-Muller codes: A technique to improve the finite-length performance}},
doi = {10.1109/tcomm.2014.2345069},
volume = {62},
year = {2014},
}
@inproceedings{773,
abstract = {We describe a new randomized consensus protocol with expected message complexity O(n2log2n) when fewer than n/2 processes may fail by crashing. This is an almost-linear improvement over the best previously known protocol, and within logarithmic factors of a known Ω(n2) message lower bound. The protocol further ensures that no process sends more than O(n log3n) messages in expectation, which is again within logarithmic factors of optimal.We also present a generalization of the algorithm to an arbitrary number of failures t, which uses expected O(nt + t2log2t) total messages. Our protocol uses messages of size O(log n), and can therefore scale to large networks.
We consider the problem of consensus in the challenging classic model. In this model, the adversary is adaptive; it can choose which processors crash at any point during the course of the algorithm. Further, communication is via asynchronous message passing: there is no known upper bound on the time to send a message from one processor to another, and all messages and coin flips are seen by the adversary.
Our approach is to build a message-efficient, resilient mechanism for aggregating individual processor votes, implementing the message-passing equivalent of a weak shared coin. Roughly, in our protocol, a processor first announces its votes to small groups, then propagates them to increasingly larger groups as it generates more and more votes. To bound the number of messages that an individual process might have to send or receive, the protocol progressively increases the weight of generated votes. The main technical challenge is bounding the impact of votes that are still “in flight” (generated, but not fully propagated) on the final outcome of the shared coin, especially since such votes might have different weights. We achieve this by leveraging the structure of the algorithm, and a technical argument based on martingale concentration bounds. Overall, we show that it is possible to build an efficient message-passing implementation of a shared coin, and in the process (almost-optimally) solve the classic consensus problem in the asynchronous message-passing model.},
author = {Alistarh, Dan and Aspnes, James and King, Valerie and Saia, Jared},
editor = {Kuhn, Fabian},
location = {Austin, USA},
pages = {61 -- 75},
publisher = {Springer},
title = {{Communication-efficient randomized consensus}},
doi = {10.1007/978-3-662-45174-8_5},
volume = {8784},
year = {2014},
}