TY - JOUR AB - The excitonic insulator phase has long been predicted to form in proximity to a band gap opening in the underlying band structure. The character of the pairing is conjectured to crossover from weak (BCS-like) to strong coupling (BEC-like) as the underlying band structure is tuned from the metallic to the insulating side of the gap opening. Here we report the high-magnetic field phase diagram of graphite to exhibit just such a crossover. By way of comprehensive angle-resolved magnetoresistance measurements, we demonstrate that the underlying band gap opening occurs inside the magnetic field-induced phase, paving the way for a systematic study of the BCS-BEC-like crossover by means of conventional condensed matter probes. AU - Zhu, Z. AU - McDonald, R. D. AU - Shekhter, A. AU - Ramshaw, B. J. AU - Modic, Kimberly A AU - Balakirev, F. F. AU - Harrison, N. ID - 7066 JF - Scientific Reports SN - 2045-2322 TI - Magnetic field tuning of an excitonic insulator between the weak and strong coupling regimes in quantum limit graphite VL - 7 ER - TY - JOUR AB - Magneto-quantum oscillation experiments in high-temperature superconductors show a strong thermally induced suppression of the oscillation amplitude approaching the critical dopings [B. J. Ramshaw et al., Science 348, 317 (2014); H. Shishido et al., Phys. Rev. Lett. 104, 057008 (2010); P. Walmsley et al., Phys. Rev. Lett. 110, 257002 (2013)]—in support of a quantum-critical origin of their phase diagrams. We suggest that, in addition to a thermodynamic mass enhancement, these experiments may directly indicate the increasing role of quantum fluctuations that suppress the quantum oscillation amplitude through inelastic scattering. We show that the traditional theoretical approaches beyond Lifshitz-Kosevich to calculate the oscillation amplitude in correlated metals result in a contradiction with the third law of thermodynamics and suggest a way to rectify this problem. AU - Shekhter, Arkady AU - Modic, Kimberly A AU - McDonald, R. D. AU - Ramshaw, B. J. ID - 7065 IS - 12 JF - Physical Review B SN - 2469-9950 TI - Thermodynamic constraints on the amplitude of quantum oscillations VL - 95 ER - TY - JOUR AB - We answer a question of M. Gromov on the waist of the unit ball. AU - Akopyan, Arseniy AU - Karasev, Roman ID - 707 IS - 4 JF - Bulletin of the London Mathematical Society SN - 00246093 TI - A tight estimate for the waist of the ball VL - 49 ER - TY - JOUR AB - In the developing and adult brain, oligodendrocyte precursor cells (OPCs) are influenced by neuronal activity: they are involved in synaptic signaling with neurons, and their proliferation and differentiation into myelinating glia can be altered by transient changes in neuronal firing. An important question that has been unanswered is whether OPCs can discriminate different patterns of neuronal activity and respond to them in a distinct way. Here, we demonstrate in brain slices that the pattern of neuronal activity determines the functional changes triggered at synapses between axons and OPCs. Furthermore, we show that stimulation of the corpus callosum at different frequencies in vivo affects proliferation and differentiation of OPCs in a dissimilar way. Our findings suggest that neurons do not influence OPCs in “all-or-none” fashion but use their firing pattern to tune the response and behavior of these nonneuronal cells. AU - Nagy, Balint AU - Hovhannisyan, Anahit AU - Barzan, Ruxandra AU - Chen, Ting AU - Kukley, Maria ID - 708 IS - 8 JF - PLoS Biology SN - 15449173 TI - Different patterns of neuronal activity trigger distinct responses of oligodendrocyte precursor cells in the corpus callosum VL - 15 ER - TY - JOUR AB - Adipose tissues play key roles in energy homeostasis. Brown adipocytes and beige adipocytes in white adipose tissue (WAT) share the similar characters of thermogenesis, both of them could be potential targets for obesity management. Several thermo-sensitive transient receptor potential channels (thermoTRPs) are shown to be involved in adipocyte biology. However, the expression pattern of thermoTRPs in adipose tissues from obese mice is still unknown. The mRNA expression of thermoTRPs in subcutaneous WAT (sWAT) and interscapular brown adipose tissue (iBAT) from lean and obese mice were measured using reverse transcriptase-quantitative PCRs (RT-qPCR). The results demonstrated that all 10 thermoTRPs are expressed in both iBAT and sWAT, and without significant difference in the mRNA expression level of thermoTRPs between these two tissues. Moreover, Trpv1 and Trpv3 mRNA expression levels in both iBAT and sWAT were significantly decreased in high fat diet (HFD)-induced obese mice and db/db (leptin receptor deficient) mice. Trpm2 mRNA expression level was significantly decreased only in sWAT from HFD-induced obese mice and db/db mice. On the other hand, Trpv2 and Trpv4 mRNA expression levels in iBAT and sWAT were significantly increased in HFD-induced obese mice and db/db mice. Taken together, we conclude that all 10 thermoTRPs are expressed in iBAT and sWAT. And several thermoTRPs differentially expressed in adipose tissues from HFD-induced obese mice and db/db mice, suggesting a potential involvement in anti-obesity regulations. AU - Sun, Wuping AU - Li, Chen AU - Zhang, Yonghong AU - Jiang, Changyu AU - Zhai, Ming-Zhu AU - Zhou, Qian AU - Xiao, Lizu AU - Deng, Qiwen ID - 709 IS - 8 JF - Cell Biology International SN - 10656995 TI - Gene expression changes of thermo sensitive transient receptor potential channels in obese mice VL - 41 ER - TY - CONF AB - We revisit the problem of estimating entropy of discrete distributions from independent samples, studied recently by Acharya, Orlitsky, Suresh and Tyagi (SODA 2015), improving their upper and lower bounds on the necessary sample size n. For estimating Renyi entropy of order alpha, up to constant accuracy and error probability, we show the following * Upper bounds n = O(1) 2^{(1-1/alpha)H_alpha} for integer alpha>1, as the worst case over distributions with Renyi entropy equal to H_alpha. * Lower bounds n = Omega(1) K^{1-1/alpha} for any real alpha>1, with the constant being an inverse polynomial of the accuracy, as the worst case over all distributions on K elements. Our upper bounds essentially replace the alphabet size by a factor exponential in the entropy, which offers improvements especially in low or medium entropy regimes (interesting for example in anomaly detection). As for the lower bounds, our proof explicitly shows how the complexity depends on both alphabet and accuracy, partially solving the open problem posted in previous works. The argument for upper bounds derives a clean identity for the variance of falling-power sum of a multinomial distribution. Our approach for lower bounds utilizes convex optimization to find a distribution with possibly worse estimation performance, and may be of independent interest as a tool to work with Le Cam’s two point method. AU - Obremski, Maciej AU - Skórski, Maciej ID - 710 SN - 18688969 TI - Renyi entropy estimation revisited VL - 81 ER - TY - JOUR AB - To determine the dynamics of allelic-specific expression during mouse development, we analyzed RNA-seq data from 23 F1 tissues from different developmental stages, including 19 female tissues allowing X chromosome inactivation (XCI) escapers to also be detected. We demonstrate that allelic expression arising from genetic or epigenetic differences is highly tissue-specific. We find that tissue-specific strain-biased gene expression may be regulated by tissue-specific enhancers or by post-transcriptional differences in stability between the alleles. We also find that escape from X-inactivation is tissue-specific, with leg muscle showing an unexpectedly high rate of XCI escapers. By surveying a range of tissues during development, and performing extensive validation, we are able to provide a high confidence list of mouse imprinted genes including 18 novel genes. This shows that cluster size varies dynamically during development and can be substantially larger than previously thought, with the Igf2r cluster extending over 10 Mb in placenta. AU - Andergassen, Daniel AU - Dotter, Christoph AU - Wenzel, Dyniel AU - Sigl, Verena AU - Bammer, Philipp AU - Muckenhuber, Markus AU - Mayer, Daniela AU - Kulinski, Tomasz AU - Theussl, Hans AU - Penninger, Josef AU - Bock, Christoph AU - Barlow, Denise AU - Pauler, Florian AU - Hudson, Quanah ID - 713 JF - eLife SN - 2050084X TI - Mapping the mouse Allelome reveals tissue specific regulation of allelic expression VL - 6 ER - TY - CONF AB - Nested weighted automata (NWA) present a robust and convenient automata-theoretic formalism for quantitative specifications. Previous works have considered NWA that processed input words only in the forward direction. It is natural to allow the automata to process input words backwards as well, for example, to measure the maximal or average time between a response and the preceding request. We therefore introduce and study bidirectional NWA that can process input words in both directions. First, we show that bidirectional NWA can express interesting quantitative properties that are not expressible by forward-only NWA. Second, for the fundamental decision problems of emptiness and universality, we establish decidability and complexity results for the new framework which match the best-known results for the special case of forward-only NWA. Thus, for NWA, the increased expressiveness of bidirectionality is achieved at no additional computational complexity. This is in stark contrast to the unweighted case, where bidirectional finite automata are no more expressive but exponentially more succinct than their forward-only counterparts. AU - Chatterjee, Krishnendu AU - Henzinger, Thomas A AU - Otop, Jan ID - 711 SN - 18688969 TI - Bidirectional nested weighted automata VL - 85 ER - TY - JOUR AB - We establish a weak–strong uniqueness principle for solutions to entropy-dissipating reaction–diffusion equations: As long as a strong solution to the reaction–diffusion equation exists, any weak solution and even any renormalized solution must coincide with this strong solution. Our assumptions on the reaction rates are just the entropy condition and local Lipschitz continuity; in particular, we do not impose any growth restrictions on the reaction rates. Therefore, our result applies to any single reversible reaction with mass-action kinetics as well as to systems of reversible reactions with mass-action kinetics satisfying the detailed balance condition. Renormalized solutions are known to exist globally in time for reaction–diffusion equations with entropy-dissipating reaction rates; in contrast, the global-in-time existence of weak solutions is in general still an open problem–even for smooth data–, thereby motivating the study of renormalized solutions. The key ingredient of our result is a careful adjustment of the usual relative entropy functional, whose evolution cannot be controlled properly for weak solutions or renormalized solutions. AU - Fischer, Julian L ID - 712 JF - Nonlinear Analysis: Theory, Methods and Applications SN - 0362546X TI - Weak–strong uniqueness of solutions to entropy dissipating reaction–diffusion equations VL - 159 ER - TY - JOUR AB - Background HIV-1 infection and drug abuse are frequently co-morbid and their association greatly increases the severity of HIV-1-induced neuropathology. While nucleus accumbens (NAcc) function is severely perturbed by drugs of abuse, little is known about how HIV-1 infection affects NAcc. Methods We used calcium and voltage imaging to investigate the effect of HIV-1 trans-activator of transcription (Tat) on rat NAcc. Based on previous neuronal studies, we hypothesized that Tat modulates intracellular Ca2+ homeostasis of NAcc neurons. Results We provide evidence that Tat triggers a Ca2+ signaling cascade in NAcc medium spiny neurons (MSN) expressing D1-like dopamine receptors leading to neuronal depolarization. Firstly, Tat induced inositol 1,4,5-trisphsophate (IP3) receptor-mediated Ca2+ release from endoplasmic reticulum, followed by Ca2+ and Na+ influx via transient receptor potential canonical channels. The influx of cations depolarizes the membrane promoting additional Ca2+ entry through voltage-gated P/Q-type Ca2+ channels and opening of tetrodotoxin-sensitive Na+ channels. By activating this mechanism, Tat elicits a feed-forward depolarization increasing the excitability of D1-phosphatidylinositol-linked NAcc MSN. We previously found that cocaine targets NAcc neurons directly (independent of the inhibition of dopamine transporter) only when IP3-generating mechanisms are concomitantly initiated. When tested here, cocaine produced a dose-dependent potentiation of the effect of Tat on cytosolic Ca2+. Conclusion We describe for the first time a HIV-1 Tat-triggered Ca2+ signaling in MSN of NAcc involving TRPC and depolarization and a potentiation of the effect of Tat by cocaine, which may be relevant for the reward axis in cocaine-abusing HIV-1-positive patients. AU - Brailoiu, Gabriela AU - Deliu, Elena AU - Barr, Jeffrey AU - Console Bram, Linda AU - Ciuciu, Alexandra AU - Abood, Mary AU - Unterwald, Ellen AU - Brǎiloiu, Eugen ID - 714 JF - Drug and Alcohol Dependence SN - 03768716 TI - HIV Tat excites D1 receptor-like expressing neurons from rat nucleus accumbens VL - 178 ER -