Miracle-dz/UniFAR-FTUs huggingface dataset:
Casing an assembler

Assemblers have been proposed as general purpose manufacturing devices, able to build a wide range of useful products as well as copies of themselves. Most proposals for assemblers involve an inside and an outside, separated by a barrier or casing. The outside is a relatively uncontrolled environment (a liquid solvent with dissolved feedstock molecules and impurities) while the inside environment is both better controlled (no impurities or undesired contaminants) and unreactive (a vacuum, or a noble gas such as neon). A graphite casing would be strong, flexible, relatively unreactive, and largely impenetrable. The use of a graphite casing raises a number of design issues: how to manufacture the new casing within the confines of the old casing, what shape the casing should have and what maintains that shape, the conditions under which the casing might fail, how to eject the new casing into the outside solvent, etc. We also discuss an improved method of using acoustic signals to power and control the assembler. In particular, the (possibly bulky) pressure-actuated pistons that were located internally to the casing in previous proposals are moved outside the casing. This lets us use pressurized neon, internally, to maintain the shape of the casing, much as the shape of an inflated balloon is maintained by internal air pressure. It also makes it easier to use larger pistons which can be driven by smaller pressure changes.
Game theoretic QoS modeling for joint resource allocation in multi-user MIMO cellular networks

This study addresses the resource allocation problem for multi-user MIMO systems with consideration of real-time services. Specifically, we focused on the delay constraints modeling in this paper, since it is a fundamental QoS requirement for all real-time services. To simultaneously meet the delay constraints of all users, we first modeled this resource allocation problem with specific delay restrictions as a bargaining game. Based on the Nash bargaining solution, we derived the system utility function that achieves delay constraints in a long term. Then, we formulated the resource allocation problem as an optimization problem through the weighted sum rate maximization, which can be solved by a modified iterative water-filling algorithm. Simulation results show that our proposed resource allocation algorithm not only achieves delay requirements for different realtime services, but also obtains the Pareto optimal efficiency with acceptable complexity.
Ownership Concentration and Firm Performance: Evidence from an Emerging Market

The initial view of the advantages of ownership concentration in joint stock companies was determined by the concern about the opportunistic managerial behavior. The growing importance of knowledge and human capital in the operation of firms shifts the focus of concern: excessive ownership concentration may stifle managerial initiative. This may be particularly true, and the results obtained in this paper support this hypothesis, in firms with high share of knowledge related activities. I explore the determinants of ownership concentration and the relationship between ownership structure and firm value in the context of a transition economy, i.e. an economy undergoing important changes in its legal and regulatory framework, in macroeconomic policy and most of all, in its property rights allocation. I focus on all non-financial companies traded on the Warsaw Stock Exchange since its inception in 1991 and up to 2003. We can observe that ownership of companies becomes more dispersed with the number of years of listing. The results reported in this paper suggest that firm adjust their ownership structure to firm specific characteristics and that firms belonging to the sector of high technology tend to have lower ownership concentration. The positive impact of ownership concentration on firm value detected in OLS regressions becomes even stronger when we control for the endogeneity of ownership.
Speaker normalization using cortical strip maps: a neural model for steady-state vowel categorization.

Auditory signals of speech are speaker dependent, but representations of language meaning are speaker independent. The transformation from speaker-dependent to speaker-independent language representations enables speech to be learned and understood from different speakers. A neural model is presented that performs speaker normalization to generate a pitch-independent representation of speech sounds, while also preserving information about speaker identity. This speaker-invariant representation is categorized into unitized speech items, which input to sequential working memories whose distributed patterns can be categorized, or chunked, into syllable and word representations. The proposed model fits into an emerging model of auditory streaming and speech categorization. The auditory streaming and speaker normalization parts of the model both use multiple strip representations and asymmetric competitive circuits, thereby suggesting that these two circuits arose from similar neural designs. The normalized speech items are rapidly categorized and stably remembered by adaptive resonance theory circuits. Simulations use synthesized steady-state vowels from the Peterson and Barney [Peterson, G. E. , and Barney, H.L. , J. Acoust. Soc. Am. 24, 175-184 (1952). ] vowel database and achieve accuracy rates similar to those achieved by human listeners. These results are compared to behavioral data and other speaker normalization models.
Shortened Ca2+ Signaling Refractoriness Underlies Cellular Arrhythmogenesis in a Postinfarction Model of Sudden Cardiac Death

Rationale: Diastolic spontaneous Ca2+ waves (DCWs) are recognized as important contributors to triggered arrhythmias. DCWs are thought to arise when [Ca2+] in sarcoplasmic reticulum ([Ca2+]SR) reaches a certain threshold level, which might be reduced in cardiac disease as a consequence of sensitization of ryanodine receptors (RyR2s) to luminal Ca2+. Objective: We investigated the mechanisms of DCW generation in myocytes from normal and diseased hearts, using a canine model of post–myocardial infarction ventricular fibrillation (VF). Methods and Results: The frequency of DCWs, recorded during periodic pacing in the presence of a &bgr;-adrenergic receptor agonist isoproterenol, was significantly higher in VF myocytes than in normal controls. Rather than occurring immediately on reaching a final [Ca2+]SR, DCWs arose with a distinct time delay after attaining steady [Ca2+]SR in both experimental groups. Although the rate of [Ca2+]SR recovery after the SR Ca2+ release was similar between the groups, in VF myocytes the latency to DCWs was shorter, and the [Ca2+]SR at DCW initiation was lower. The restitution of depolarization-induced Ca2+ transients, assessed by a 2-pulse protocol, was significantly faster in VF myocytes than in controls. The VF-related alterations in myocyte Ca2+ cycling were mimicked by the RyR2 agonist, caffeine. The reducing agent, mercaptopropionylglycine, or the CaMKII inhibitor, KN93, decreased DCW frequency and normalized restitution of Ca2+ release in VF myocytes. Conclusions: The attainment of a certain threshold [Ca2+]SR is not sufficient for the generation of DCWs. Postrelease Ca2+ signaling refractoriness critically influences the occurrence of DCWs. Shortened Ca2+ signaling refractoriness due to RyR2 phosphorylation and oxidation is responsible for the increased rate of DCWs observed in VF myocytes and could provide a substrate for synchronization of arrhythmogenic events at the tissue level in hearts prone to VF.
Summarization and Interaction Techniques for Enhancing the Learning Experience of How-to Videos

Video tutorials on the web have gained popularity, but most video repositories do not take into account the unique structure of how-to videos. Learners face difficulties in finding and watching relevant videos due to limited support for step-by-step navigation. We introduce ToolScape, a system for browsing and watching how-to videos powered by step-by-step annotations. It features the Storyboard summarization, which allows learners to quickly scan and review multiple videos, and the interactive timeline, which enables jumping to or repeating a particular step within a workflow. In a comparative study of three summarization techniques, learners found relevant videos in least time with Storyboard. In another study where participants engaged in design tasks with ToolScape and a control interface, the participants using ToolScape gained more self-efficacy, rated their own designs higher, and produced better designs. The study demonstrates the effectiveness of interactivity and learner control enabled by step-by-step navigation of how-to videos.
Machine Learning and Portfolio Optimization

The portfolio optimization model has limited impact in practice because of estimation issues when applied to real data. To address this, we adapt two machine learning methods, regularization and cross-validation, for portfolio optimization. First, we introduce performance-based regularization PBR, where the idea is to constrain the sample variances of the estimated portfolio risk and return, which steers the solution toward one associated with less estimation error in the performance. We consider PBR for both mean-variance and mean-conditional value-at-risk CVaR problems. For the mean-variance problem, PBR introduces a quartic polynomial constraint, for which we make two convex approximations: one based on rank-1 approximation and another based on a convex quadratic approximation. The rank-1 approximation PBR adds a bias to the optimal allocation, and the convex quadratic approximation PBR shrinks the sample covariance matrix. For the mean-CVaR problem, the PBR model is a combinatorial optimization problem, but we prove its convex relaxation, a quadratically constrained quadratic program, is essentially tight. We show that the PBR models can be cast as robust optimization problems with novel uncertainty sets and establish asymptotic optimality of both sample average approximation SAA and PBR solutions and the corresponding efficient frontiers. To calibrate the right-hand sides of the PBR constraints, we develop new, performance-based k-fold cross-validation algorithms. Using these algorithms, we carry out an extensive empirical investigation of PBR against SAA, as well as L1 and L2 regularizations and the equally weighted portfolio. We find that PBR dominates all other benchmarks for two out of three Fama-French data sets. This paper was accepted by Yinyu Ye, optimization.
Altered Feeding Patterns in Rats Exposed to a Palatable Cafeteria Diet: Increased Snacking and Its Implications for Development of Obesity

Background Rats prefer energy-rich foods over chow and eat them to excess. The pattern of eating elicited by this diet is unknown. We used the behavioral satiety sequence to classify an eating bout as a meal or snack and compared the eating patterns of rats fed an energy rich cafeteria diet or chow. Methods Eight week old male Sprague Dawley rats were exposed to lab chow or an energy-rich cafeteria diet (plus chow) for 16 weeks. After 5, 10 and 15 weeks, home-cage overnight feeding behavior was recorded. Eating followed by grooming then resting or sleeping was classified as a meal; whereas eating not followed by the full sequence was classified as a snack. Numbers of meals and snacks, their duration, and waiting times between feeding bouts were compared between the two conditions. Results Cafeteria-fed rats ate more protein, fat and carbohydrate, consistently ingesting double the energy of chow-fed rats, and were significantly heavier by week 4. Cafeteria-fed rats tended to take multiple snacks between meals and ate fewer meals than chow-fed rats. They also ate more snacks at 5 weeks, were less effective at compensating for snacking by reducing meals, and the number of snacks in the majority of the cafeteria-fed rats was positively related to terminal body weights. Conclusions Exposure to a palatable diet had long-term effects on feeding patterns. Rats became overweight because they initially ate more frequently and ultimately ate more of foods with higher energy density. The early increased snacking in young cafeteria-fed rats may represent the establishment of eating habits that promote weight gain.
On the design of perturbation-resilient atomic commit protocols for mobile transactions

Distributed mobile transactions utilize commit protocols to achieve atomicity and consistent decisions. This is challenging, as mobile environments are typically characterized by frequent perturbations such as network disconnections and node failures. On one hand environmental constraints on mobile participants and wireless links may increase the resource blocking time of fixed participants. On the other hand frequent node and link failures complicate the design of atomic commit protocols by increasing both the transaction abort rate and resource blocking time. Hence, the deployment of classical commit protocols (such as two-phase commit) does not reasonably extend to distributed infrastructure-based mobile environments driving the need for perturbation-resilient commit protocols. In this article, we comprehensively consider and classify the perturbations of the wireless infrastructure-based mobile environment according to their impact on the outcome of commit protocols and on the resource blocking times. For each identified perturbation class a commit solution is provided. Consolidating these subsolutions, we develop a family of fault-tolerant atomic commit protocols that are tunable to meet the desired perturbation needs and provide minimized resource blocking times and optimized transaction commit rates. The framework is also evaluated using simulations and an actual testbed deployment.
Effects of retinal glial cells on isolated rat retinal ganglion cells.

PURPOSE The effect of retinal glial cells on retinal ganglion cell (RGC) survival was investigated in cocultures of pure, isolated retinal glial cells with pure, isolated RGCs. METHODS RGCs from 2-day-old rats were cocultured for 48 hours, avoiding direct contact between cell types, with either nonconfluent retinal glial cells from 3-day-old rats or confluent retinal glial cells from 3-day-old, 12-day-old, or 1-year-old rats. Survival of RGCs was evaluated by flow cytometry. Amino acids were determined in culture medium. The effects of glutamate antagonists, 6-cyano-7-nitroquinoxaline-2,3-dione and MK801, a nitric oxide (NO) scavenger, 2-(4-carboxyphenyl)-4,4,5,5tetramethylimidazoline-1-oxyl-3-oxide potassium salt (c-PTIO), and an NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), were examined. RESULTS Nonconfluent retinal glial cells significantly reduced the survival of small and large RGCs, but confluent retinal glial cells reduced the survival of only small RGCs, regardless of the rat's age at the time of retinal glial cell harvesting. Profiles of some amino acids significantly varied, depending on the culture condition. Cocultures of RGCs with nonconfluent retinal glial cells released significantly more glutamate into the medium than cocultures of RGCs with confluent retinal glial cells or RGCs in pure culture. The glutamate antagonists improved the survival of RGCs cocultured with nonconfluent retinal glial cells, especially when the two were administered in combination, and in the case of large RGCs. c-PTIO and L-NAME, also improved the survival of RGCs cocultured with nonconfluent retinal glial cells. CONCLUSIONS Adverse effects of retinal glial cells on the survival of RGCs varied by size of the RGCs and retinal glial cell confluence. Glutamate and NO may be involved in retinal glial cell-related antisurvival effects.
The Lipid-RNA World

The simplest possible beginning of abiogenesis has been a riddle from the last century, which is most successfully solved by the Lipid World hypothesis. However, origin of the next stages of evolution starting form lipids is still in dark. We propose a 'Lipid-RNA World Scenario' based on the assumption that modern stable lipid-RNA interactions are molecular fossils of an ancient stage of evolution when RNA World originated from Lipid World. In accordance to the faint young sun conditions, we present an 'ice-covered hydrothermal vent' model of Hadean Ocean. Our hypothetical model suggests that faint young sun condition probably provided susceptible physical conditions for an evolutionary route from Lipid-World to Protein-RNA World, through an intermediate Lipid-RNA World. Ancient ribozymes were 'protected' by lipids assuring their survival in prebiotic ocean. The origin of natural selection ensures transition of Lipid-RNA World to Protein-RNA World after the origin of ribosome. Assuming the modern peptidyltransferase as the proto-ribosome structure, we have presented a hypothetical translation mechanism: proto-ribosome randomly polymerized amino acids being attached to the inner layer of a lipid-vesicle, using only physical energies available from our Hadean Ocean model. In accordance to the strategy of chemical evolution, we also have described the possible evolutionary behavior of this proto-ribosome, which explains the contemporary three-dimensional structure of 50S subunit and supports the predictions regarding the ancient regions of it. It also explains the origin of membrane-free 'minimal ribosome' in the time of LUCA.
Development and implementation of a coupled computational muscle force optimization bone shape adaptation modeling method

Improved methods to analyze and compare the muscle‐based influences that drive bone strength adaptation can aid in the understanding of the wide array of experimental observations about the effectiveness of various mechanical countermeasures to losses in bone strength that result from age, disuse, and reduced gravity environments. The coupling of gradient‐based and gradientless numerical optimization routines with finite element methods in this work results in a modeling technique that determines the individual magnitudes of the muscle forces acting in a multisegment musculoskeletal system and predicts the improvement in the stress state uniformity and, therefore, strength, of a targeted bone through simulated local cortical material accretion and resorption. With a performance‐based stopping criteria, no experimentally based or system‐based parameters, and designed to include the direct and indirect effects of muscles attached to the targeted bone as well as to its neighbors, shape and strength alterations resulting from a wide range of boundary conditions can be consistently quantified. As demonstrated in a representative parametric study, the developed technique effectively provides a clearer foundation for the study of the relationships between muscle forces and the induced changes in bone strength. Its use can lead to the better control of such adaptive phenomena. Copyright © 2015 John Wiley & Sons, Ltd.
K‐ras and p53 Alterations in Genomic DNA and Transcripts of Human Pancreatic Adenocarcinoma Cell Lines

We analyzed 15 human pancreatic adenocarcinoma cell lines for alterations of the K‐ras and the p53 genes and their transcripts. In 11 cell lines (73.3%), point mutations of the K‐ras gene were found at codon 12 in exon 1. In 9 cell lines one allele was mutated and the other was wild type, and both the alleles were expressed into mRNA. In one cell line both alleles of codon 12 were mutated to TGT and GTT, respectively, hut only TGT was transcribed into mRNA. Alterations in mRNA of the p53 gene were detected in 10 cell lines (66.7%). Analysis of the genomlc sequence of the p53 gene revealed that the alterations consisted of 6 cases of base pair substitutions and 1 case of 1‐bp deletion in evolutionarily conserved exons 5 to 8, 2 cases of splicing mutations in exon 4, and 1 case of novel deletion from exons 2 to 9. In 14 cell lines (93.3%), alterations were identified in the K‐ras or p53 gene. Of these, 4 cell lines harbored K‐ras mutations without p53 alteration, whereas 3 cell lines exhibited p53 alterations without K‐ras mutation. Thus, it is suggested that activation of the K‐ras gene and inactivation of the p53 gene are strongly and cooperatively associated with pancreatic carcinogenesis.
Intermittent Hypoxia Effect on Osteoclastogenesis Stimulated by Neuroblastoma Cells

Background Neuroblastoma is the most common extracranial pediatric solid tumor. Intermittent hypoxia, which is characterized by cyclic periods of hypoxia and reoxygenation, has been shown to positively modulate tumor development and thereby induce tumor growth, angiogenic processes, and metastasis. Bone is one of the target organs of metastasis in advanced neuroblastoma Neuroblastoma cells produce osteoclast-activating factors that increase bone resorption by the osteoclasts. The present study focuses on how intermittent hypoxia preconditioned SH-SY5Y neuroblastoma cells modulate osteoclastogenesis in RAW 264.7 cells compared with neuroblastoma cells grown at normoxic conditions. Methods We inhibited HIF-1α and HIF-2α in neuroblastoma SH-SY5Y cells by siRNA/shRNA approaches. Protein expression of HIF-1α, HIF-2α and MAPKs were investigated by western blotting. Expression of osteoclastogenic factors were determined by real-time RT-PCR. The influence of intermittent hypoxia and HIF-1α siRNA on migration of neuroblastoma cells and in vitro differentiation of RAW 264.7 cells were assessed. Intratibial injection was performed with SH-SY5Y stable luciferase-expressing cells and in vivo bioluminescence imaging was used in the analysis of tumor growth in bone. Results Upregulation of mRNAs of osteoclastogenic factors VEGF and RANKL was observed in intermittent hypoxia-exposed neuroblastoma cells. Conditioned medium from the intermittent hypoxia-exposed neuroblastoma cells was found to enhance osteoclastogenesis, up-regulate the mRNAs of osteoclast marker genes including TRAP, CaSR and cathepsin K and induce the activation of ERK, JNK, and p38 in RAW 264.7 cells. Intermittent hypoxia-exposed neuroblastoma cells showed an increased migratory pattern compared with the parental cells. A significant increase of tumor volume was found in animals that received the intermittent hypoxia-exposed cells intratibially compared with parental cells. Conclusions Intermittent hypoxic exposure enhanced capabilities of neuroblastoma cells in induction of osteoclast differentiation in RAW 264.7 cells. Increased migration and intratibial tumor growth was observed in intermittent hypoxia-exposed neuroblastoma cells compared with parental cells.
Nurses' detection of ineffective inspiratory efforts during mechanical ventilation.

UNLABELLED BACKGROUND PATIENT: ventilator dyssynchrony is common and may influence patients' outcomes. Detection of such dyssynchronies relies on careful observation of patients and airway flow and pressure measurements. Given the shortage of specialists, critical care nurses could be trained to identify dyssynchronies. OBJECTIVE To evaluate the accuracy of specifically trained critical care nurses in detecting ineffective inspiratory efforts during expiration. METHODS We compared 2 nurses' evaluations of measurements from 1007 breaths in 8 patients with the evaluations of experienced critical care physicians. Sensitivity, specificity, positive predictive value, negative predictive value, and the Cohen κ for interobserver agreement were calculated. RESULTS For the first nurse, sensitivity was 92.5%, specificity was 98.3%, positive predictive value was 95.4%, negative predictive value was 97.1%, and κ was 0.92 (95% CI, 0.89-0.94). For the second nurse, sensitivity was 98.5%, specificity was 84.7%, positive predictive value was 70.7%, negative predictive value was 99.3%, and κ was 0.74 (95% CI, 0.70-0.78). CONCLUSION Specifically trained nurses can reliably detect ineffective inspiratory efforts during expiration.