1,180 research outputs found

    Absolute continuity of Wasserstein barycenters on manifolds with a lower Ricci curvature bound

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    Given a complete Riemannian manifold MM with a lower Ricci curvature bound, we consider barycenters in the Wasserstein space W2(M)\mathcal{W}_2(M) of probability measures on MM. We refer to them as Wasserstein barycenters, which by definition are probability measures on MM. The goal of this article is to present a novel approach to proving their absolute continuity. We introduce a new class of displacement functionals exploiting the Hessian equality for Wasserstein barycenters. To provide suitable instances of such functionals, we revisit Souslin space theory, Dunford-Pettis theorem and the de la Vall\'ee Poussin criterion for uniform integrability. Our method shows that if a probability measure P\mathbb{P} on W2(M)\mathcal{W}_2(M) gives mass to absolutely continuous measures on MM, then its unique barycenter is also absolutely continuous. This generalizes the previous results on compact manifolds by Kim and Pass arXiv:1412.7726 [math.AP]

    FreePSI: an alignment-free approach to estimating exon-inclusion ratios without a reference transcriptome.

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    Alternative splicing plays an important role in many cellular processes of eukaryotic organisms. The exon-inclusion ratio, also known as percent spliced in, is often regarded as one of the most effective measures of alternative splicing events. The existing methods for estimating exon-inclusion ratios at the genome scale all require the existence of a reference transcriptome. In this paper, we propose an alignment-free method, FreePSI, to perform genome-wide estimation of exon-inclusion ratios from RNA-Seq data without relying on the guidance of a reference transcriptome. It uses a novel probabilistic generative model based on k-mer profiles to quantify the exon-inclusion ratios at the genome scale and an efficient expectation-maximization algorithm based on a divide-and-conquer strategy and ultrafast conjugate gradient projection descent method to solve the model. We compare FreePSI with the existing methods on simulated and real RNA-seq data in terms of both accuracy and efficiency and show that it is able to achieve very good performance even though a reference transcriptome is not provided. Our results suggest that FreePSI may have important applications in performing alternative splicing analysis for organisms that do not have quality reference transcriptomes. FreePSI is implemented in C++ and freely available to the public on GitHub

    Effect of architectural adjustments on pedestrian flow at bottleneck

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    In the last decades, a series of terrible accidents happened within pedestrian crowds, which makes crowd dynamic a significant issue to be investigated. Literature reviews show that pedestrian flow presents different features within different architectural layout. In this paper, pedestrian movement properties at bottleneck are studied by carrying out series of experiments under laboratory condition. The influence of door sizes and exit locations on pedestrian crowd flow is investigated. It was found that larger door width resulted in shorter evacuation time and faster flow rate. By comparing the fundamental diagram among crowd evacuation, the average velocity increases as the width increases under the same density condition. Interestingly, the influence of the boundary layer, as well as the effective width on pedestrian crowd dynamic, was clearly observed. Our results suggest that the combination of exit width and location resulted in a synergistic effect, but the exit widths gradually became the most important factor influencing the flow rate

    Wealth Effects Of Bank Mergers And Acquisitions In Asian Emerging Markets

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    Through analysis of stock responses to two different types of banking M&A deals, specifying M&A and diversifying M&A, we find that specifying M&A deals incur positive cumulative abnormal returns (CAR) in both two-day and three-day windows without controlling for firm size. Diversifying M&A deals incur positive CAR in two different event windows. However, the differences between the two windows are not statistically significant. Contrary to previous studies on M&A in the banking industry of developed markets, the results of our study indicate that markets do not distinguish among various types of M&A deals in the banking industry around the date of announcement. Diversifying M&A generate positive three-day CARs but they are not significantly better than specifying M&A

    Research progress on the development of pennycress (Thlaspi arvense L.) as a new seed oil crop: a review

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    Compared with other crops, pennycress (Thlaspi arvense L.) is a niche emerging oil crop. In recent years, research on pennycress has been increasingly reflected in various directions. Pennycress belongs to the Brassicaceae family and was introduced from Eurasia to North America. It has been found worldwide as a cultivated plant and weed. In this paper, we review the advantages of pennycress as a supplementary model plant of Arabidopsis thaliana, oil and protein extraction technology, seed composition analysis based on metabolomics, germplasm resource development, growth, and ecological impact research, abiotic stress, fatty acid extraction optimization strategy, and other aspects of studies over recent years. The main research directions proposed for the future are as follows: (1) assemble the genome of pennycress to complete its entire genome data, (2) optimize the extraction process of pennycress as biodiesel, (3) analyze the molecular mechanism of the fatty acid synthesis pathway in pennycress, and (4) the functions of key genes corresponding to various adversity conditions of pennycress

    Cardiac Specific Overexpression of Mitochondrial Omi/HtrA2 Induces Myocardial Apoptosis and Cardiac Dysfunction.

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    Myocardial apoptosis is a significant problem underlying ischemic heart disease. We previously reported significantly elevated expression of cytoplasmic Omi/HtrA2, triggers cardiomyocytes apoptosis. However, whether increased Omi/HtrA2 within mitochondria itself influences myocardial survival in vivo is unknown. We aim to observe the effects of mitochondria-specific, not cytoplasmic, Omi/HtrA2 on myocardial apoptosis and cardiac function. Transgenic mice overexpressing cardiac-specific mitochondrial Omi/HtrA2 were generated and they had increased myocardial apoptosis, decreased systolic and diastolic function, and decreased left ventricular remodeling. Transiently or stably overexpression of mitochondria Omi/HtrA2 in H9C2 cells enhance apoptosis as evidenced by elevated caspase-3, -9 activity and TUNEL staining, which was completely blocked by Ucf-101, a specific Omi/HtrA2 inhibitor. Mechanistic studies revealed mitochondrial Omi/HtrA2 overexpression degraded the mitochondrial anti-apoptotic protein HAX-1, an effect attenuated by Ucf-101. Additionally, transfected cells overexpressing mitochondrial Omi/HtrA2 were more sensitive to hypoxia and reoxygenation (H/R) induced apoptosis. Cyclosporine A (CsA), a mitochondrial permeability transition inhibitor, blocked translocation of Omi/HtrA2 from mitochondrial to cytoplasm, and protected transfected cells incompletely against H/R-induced caspase-3 activation. We report in vitro and in vivo overexpression of mitochondrial Omi/HtrA2 induces cardiac apoptosis and dysfunction. Thus, strategies to directly inhibit Omi/HtrA2 or its cytosolic translocation from mitochondria may protect against heart injury

    Silent messages in negotiations: The role of nonverbal communication in cross-cultural business negotiations

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    This study specifically explored the perceived importance of the following nonverbal factors in the negotiation process: proxemics (location and negotiation site), physical arrangement (seating and furniture arrangement), and kinesics (eye contact, facial expressions and gestures). The participants are professional business negotiators of different nationalities. The findings show that the negotiators\u27 perception about the three factors and their roles in negotiation are consistent with the nonverbal communication literature

    The Impact of Operating Parameters on the Gas-Phase Sulfur Concentration after High Temperature Sulfur Sorption on a Supported Mo-Mn Sorbent

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    The impact of operating parameters on H2S capture from a syngas mixture by a Mo-promoted Mn-based high-temperature sorbent was investigated. The parameters investigated included temperature, space velocity, H2S concentration in the feed gas, and steam content. The H2S and SO2 concentrations in the gas after passing over a bed of the sorbent were analyzed and compared with thermodynamic calculations. The results confirmed that low temperature, low space velocity, low H2S concentration, and a dry feed were favorable for achieving a low residual concentration of sulfur compounds in the effluent gas. The sorbent was able to reduce the residual H2S concentration to below 1 ppm under all tested conditions. However, the unavoidable steam content in the gas phase had a significant adverse effect on sulfur removal from the gas. An empirical model, containing the three variables, i.e., temperature, space velocity, and H2S concentration in the feed, was developed and can be used to predict the effluent H2S residual concentration after treatment by the 15Mn8Mo sorbent.publishedVersio

    Joint Synthesis of Safety Certificate and Safe Control Policy using Constrained Reinforcement Learning

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    Safety is the major consideration in controlling complex dynamical systems using reinforcement learning (RL), where the safety certificate can provide provable safety guarantee. A valid safety certificate is an energy function indicating that safe states are with low energy, and there exists a corresponding safe control policy that allows the energy function to always dissipate. The safety certificate and the safe control policy are closely related to each other and both challenging to synthesize. Therefore, existing learning-based studies treat either of them as prior knowledge to learn the other, which limits their applicability with general unknown dynamics. This paper proposes a novel approach that simultaneously synthesizes the energy-function-based safety certificate and learns the safe control policy with CRL. We do not rely on prior knowledge about either an available model-based controller or a perfect safety certificate. In particular, we formulate a loss function to optimize the safety certificate parameters by minimizing the occurrence of energy increases. By adding this optimization procedure as an outer loop to the Lagrangian-based constrained reinforcement learning (CRL), we jointly update the policy and safety certificate parameters and prove that they will converge to their respective local optima, the optimal safe policy and a valid safety certificate. We evaluate our algorithms on multiple safety-critical benchmark environments. The results show that the proposed algorithm learns provably safe policies with no constraint violation. The validity or feasibility of synthesized safety certificate is also verified numerically.Comment: 24 pages, 8 figures, accepted for oral presentation at L4DC 202
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