Miracle-dz/UniFAR-FTUs huggingface dataset:
Approximation algorithms for classification problems with pairwise relationships: metric labeling and Markov random fields

In a traditional classification problem, we wish to assign one of k labels (or classes) to each of n objects, in a way that is consistent with some observed data that we have about the problem. An active line of research in this area is concerned with classification when one has information about pairwise relationships among the objects to be classified; this issue is one of the principal motivations for the framework of Markov random fields, and it arises in areas such as image processing, biometry: and document analysis. In its most basic form, this style of analysis seeks a classification that optimizes a combinatorial function consisting of assignment costs-based on the individual choice of label we make for each object-and separation costs-based on the pair of choices we make for two "related" objects. We formulate a general classification problem of this type, the metric labeling problem; we show that it contains as special cases a number of standard classification frameworks, including several arising from the theory of Markov random fields. From the perspective of combinatorial optimization, our problem can be viewed as a substantial generalization of the multiway cut problem, and equivalent to a type of uncapacitated quadratic assignment problem. We provide the first non-trivial polynomial-time approximation algorithms for a general family of classification problems of this type. Our main result is an O(log k log log k)-approximation algorithm for the metric labeling problem, with respect to an arbitrary metric on a set of k labels, and an arbitrary weighted graph of relationships on a set of objects. For the special case in which the labels are endowed with the uniform metric-all distances are the same-our methods provide a 2-approximation.
New Limits on a Cosmological Constant from Statistics of Gravitational Lensing

We present new limits on cosmological parameters from the statistics of gravitational lensing, based on the recently revised knowledge of the luminosity function and internal dynamics of E/S0 galaxies that are essential in lensing high-redshift QSOs. We find that the lens models using updated Schechter parameters for such galaxies, derived from the recent redshift surveys combined with morphological classification, are found to give smaller lensing probabilities than were calculated earlier. Inconsistent adoption of these parameters from a mixture of various galaxy surveys gives rise to systematic biases in the results. We also show that less compact dwarf-type galaxies that largely dominate the faint part of the Schechter form luminosity function contribute little to lensing probabilities, so that earlier lens models overestimate incidents of small separation lenses. Applications of the lens models to the existing lens surveys indicate that reproduction of both the lensing probability of optical sources and the image separations of optical and radio lenses is significantly improved in the revised lens models. The likelihood analyses allow us to conclude that a flat universe with Ω0=0.3 and Ω0+λ0=1 is preferable, and a matter-dominated flat universe with λ0=0 is ruled out at the 98% confidence level. These new limits are unaffected by the inclusion of uncertainties in the lens properties.
Decrease of Fibulin-3 in Hepatocellular Carcinoma Indicates Poor Prognosis

Fibulin-3, originally identified in senescent and Werner syndrome fibroblasts, has been implicated in cell morphology, growth, adhesion and motility. Fibulin-3 exhibits both antitumor and oncogenic activities towards human cancers; however, the role of Fibulin-3 in hepatocellular carcinoma (HCC) remains elusive. In this study, we showed that both the mRNA and protein levels of Fibulin-3 were remarkably downregulated in HCC cell lines and fresh tissues. Immunohistochemical data revealed that Fibulin-3 was decreased in tumorous tissues in 67.1% (171/255) of cases compared to the corresponding adjacent nontumorous tissues. The results of statistical analysis indicated that low Fibulin-3 expression, defined by the receiver operating characteristic curve (ROC), was significantly associated with tumor differentiation (P = 0.008), clinical stage (P = 0.014) and serum AFP levels (P<0.01). Furthermore, Kaplan-Meier and multivariate analysis suggested that Fibulin-3 is an independent negative prognostic indicator for both overall (P<0.001) and recurrence-free (P = 0.036) survival. In addition, an in vitro study demonstrated that knockdown of Fibulin-3 by siRNA markedly increased cell viability and promoted cell invasion in HCC cells. Collectively, our data suggest that Fibulin-3 exhibits antitumor effects towards HCC and serves as a biomarker of unfavorable prognosis for this deadly disease.
Evaluation of a recombinant yeast cell estrogen screening assay.

A wide range of chemicals with diverse structures derived from plant and environmental origins are reported to have hormonal activity. The potential for appreciable exposure of humans to such substances prompts the need to develop sensitive screening methods to quantitate and evaluate the risk to the public. Yeast cells transformed with plasmids encoding the human estrogen receptor and an estrogen responsive promoter linked to a reporter gene were evaluated for screening compounds for estrogenic activity. Relative sensitivity to estrogens was evaluated by reference to 17 beta-estradiol (E2) calibration curves derived using the recombinant yeast cells, MCF-7 human breast cancer cells, and a prepubertal mouse uterotrophic bioassay. The recombinant yeast cell bioassay (RCBA) was approximately two and five orders of magnitude more sensitive to E2 than MCF-7 cells and the uterotrophic assay, respectively. The estrogenic potency of 53 chemicals, including steroid hormones, synthetic estrogens, environmental pollutants, and phytoestrogens, was measured using the RCBA. Potency values produced with the RCBA relative to E2 (100) included estrone (9.6), diethylstilbestrol (74.3), tamoxifen (0.0047), alpha-zearalanol (1.3), equol (0.085), 4-nonylphenol (0.005), and butylbenzyl phathalate (0.0004), which were similar to literature values but generally higher than those produced by the uterotrophic assay. Exquisite sensitivity, absence of test compound biotransformation, ease of use, and the possibility of measuring antiestrogenic activity are important attributes that argue for the suitability of the RCBA in screening for potential xenoestrogens to evaluate risk to humans, wildlife, and the environment. ImagesFigure 1.Figure 2.Figure 3.Figure 4.
Taylor Rules and Inflation Targeting do not Work with Systematic Foreign Exchange Market Intervention

This paper examines how the systematic attempt to influence directly the path of the nominal exchange rate due to “fear of floating” affects the conduct of monetary policy under a Taylor rule and inflation targeting. The paper demonstrates that implementing a Taylor rule or an inflation-targeting scheme simultaneously with policies that try to moderate the rate of depreciation of the nominal exchange rate may result in an inconsistent monetary policy. In addition, the paper shows in a relatively simple framework the close theoretical connection between a Taylor rule and inflation targeting. ∗ This article does not reflect the opinion of the Central Bank of Venezuela. Professor Stephen Miller (University of Nevada at Las Vegas) made important contributions to previous versions of the paper. Any remaining errors are the sole responsibility of the author. 1.Introduction Inflation targeting became widely popular among central banks during the 1990s. The first wave of central banks that adopted inflation targeting in the first half o this decade was mainly from industrialized countries. In the late 1990s, however, several Latin American central banks embarked on inflation targeting. Currently, the central banks of Chile, Mexico, Brazil and Colombia practice inflation targeting. Jointly with the spreading of inflation targeting, there has been an explosion on the literature that covers different practical and theoretical aspects of this monetary policy regime. Bofinger (2001), however, points out that in contrast to monetary targeting that was applied by central banks after intensive academic discussion, inflation targeting was first put in practice by central banks and then researchers began to produce the theoretical support. Most of the literature available on inflation targeting has focused on country experiences with the scheme (Leiderman and Svensson, 1995, Bernanke et al 1999); implementation of inflation targeting as inflation forecast targeting (Svensson, 1996); analysis of the responses to different shocks, consequences of model uncertainty, effects of interest rate smoothing and stabilization, comparison with nominal GDP targeting, and implications of forward-looking behavior (Svensson, 1997); studying inflation targeting in the context of monetary policy rules (Svensson, 1998); examining the efficiency of inflation targeting in relation to Taylor rules in closed economies (Ball, 1997) and open economies (Ball, 1998). Although inflation targeting currently reflects the monetary policy strategy of choice of those countries that want to provide the economy with a nominal anchor while avoiding the excessive rigidity of “hard” or “soft” pegs, Calvo and Reinhart (2000) argue
Platelets: Developmental biology, physiology, and translatable platforms for preclinical investigation and drug development

This paper, developed from the proceedings of the 2007 Platelet Colloquium, considers emerging constructs in platelet biology, preclinical models of thrombosis, and their potential application to the development of platelet-directed pharmacotherapies. Discussed first is the developmental biology of platelets, including megakaryocyte maturation, and the role of apoptotic and growth factors and other proteins in thrombopoiesis. A brief overview of current methods and observations from platelet proteomic analyses is also presented, illustrating the complex interplay of genes, gene expression, protein expression, and protein modification in various atherothrombotic phenotypes. The factor Xa-platelet interface is used as a working model for discussion of anticoagulants as platelet antagonists, highlighting the importance of receptor expression, substrate binding kinetics, platelet subpopulations, and cofactors in thrombosis. Finally, we discuss the use of emerging technologies—such as intravital microscopy and ex vivo perfusion chambers—as translatable platforms for investigating the role of platelets and their pharmacologic inhibition in human health and disease.
Molecular Dynamics Simulations of the Adenosine A2a Receptor: Structural Stability, Sampling, and Convergence

Molecular dynamics (MD) simulations of membrane-embedded G-protein coupled receptors (GPCRs) have rapidly gained popularity among the molecular simulation community in recent years, a trend which has an obvious link to the tremendous pharmaceutical importance of this group of receptors and the increasing availability of crystal structures. In view of the widespread use of this technique, it is of fundamental importance to ensure the reliability and robustness of the methodologies so they yield valid results and enable sufficiently accurate predictions to be made. In this work, 200 ns simulations of the A2a adenosine receptor (A2a AR) have been produced and evaluated in the light of these requirements. The conformational dynamics of the target protein, as obtained from replicate simulations in both the presence and absence of an inverse agonist ligand (ZM241385), have been investigated and compared using principal component analysis (PCA). Results show that, on this time scale, convergence of the replicates is not readily evident and dependent on the types of the protein motions considered. Thus rates of inter- as opposed to intrahelical relaxation and sampling can be different. When studied individually, we find that helices III and IV have noticeably greater stability than helices I, II, V, VI, and VII in the apo form. The addition of the inverse agonist ligand greatly improves the stability of all helices.
How Better Information Can Reduce the Credibility of Experts' Advice

Two experts make yes/no predictions about whether an event, such as an economic crisis, will occur. They receive private signals about the likelihood of the event that are much more informative than the coarse recommendations they can ultimately convey. The experts may care about both absolute and relative performance. We show that when both experts receive strictly better information, the error rates of their all their unanimous predictions in the new equilibrium may be higher than before the information improvement. This unintuitive phenomenon raises the question of how society can optimally incentivize such experts. We find that, without the possibility of huge transfers, society's ability to extract good advice or even to interpret imperfect advice is severely limited.
Evaluating and improving the assessment and consistency of feedback within the Clinical Skills Laboratory at Dundee Dental School

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Sex‐Specific Spawning Behavior and Its Consequences in an External Fertilizer

Identifying the target of sexual selection in externally fertilizing taxa has been problematic because species in these taxa often lack sexual dimorphism. However, these species often show sex differences in spawning behavior; males spawn before females. I investigated the consequences of spawning order and time intervals between male and female spawning in two field experiments. The first involved releasing one female sea urchin’s eggs and one or two males’ sperm in discrete puffs from syringes; the second involved inducing males to spawn at different intervals in situ within a population of spawning females. In both, fertilization success was measured as the fraction of eggs fertilized and the paternity share of each male. The results indicate that spawning after females imposes a cost on males but only during sperm competition. Further, the optimal interval between the initiations of male and female spawning depends on degree of sperm competition, distance between males and females, and water velocity. The results show that sex differences in spawning timing of marine invertebrates can be explained on the basis of the differential costs and benefits of spawning out of synchrony with the other sex and that the result of sexual selection on external fertilizers may be behavioral rather than morphological differentiation of the sexes.
Identifying online opinion leaders using K-means clustering

Online opinion leaders play an important role in the dissemination of information in discussion forums. They are a high-priority target group for viral marketing campaigns. On an average, an opinion leader will tell about his or her experience with a product or company to 14 other people. It is important to identify such opinion leaders from data derived from online activity of users. We present an approach to identification of opinion leaders using the K-means clustering algorithm. This approach does not require knowledge of the user's opinions or membership in other forums.
Regenerative tree growth: structural results and convergence

We introduce regenerative tree growth processes as consistent families of random trees with n labelled leaves, n>=1, with a regenerative property at branch points. This framework includes growth processes for exchangeably labelled Markov branching trees, as well as non-exchangeable models such as the alpha-theta model, the alpha-gamma model and all restricted exchangeable models previously studied. Our main structural result is a representation of the growth rule by a sigma-finite dislocation measure kappa on the set of partitions of the natural numbers extending Bertoin's notion of exchangeable dislocation measures from the setting of homogeneous fragmentations. We use this representation to establish necessary and sufficient conditions on the growth rule under which we can apply results by Haas and Miermont for unlabelled and not necessarily consistent trees to establish self-similar random trees and residual mass processes as scaling limits. While previous studies exploited some form of exchangeability, our scaling limit results here only require a regularity condition on the convergence of asymptotic frequencies under kappa, in addition to a regular variation condition.
A Survey of Imprecise Signal Processing

Approximate computations allow for trading off between precision and other desired qualities like low energy consumption in a portable device with a limited battery life, or reduction in arithmetic complexities in favor of faster computations in a station. Signal processing applications are widely used in almost every aspect of our modern life including multimedia. What’s interesting is that signal processing algorithms can be structured to allow for approximate computations. Due to these applications’ inherent errorresiliency, trading off between accuracy in computation and other qualities will result in a more efficient system in terms of resource utilization with little degradation in quality. In this work, after examination of recent approaches in this field, we will compare them and suggest a hybrid method for realization of an even more efficient systems. Also a hypothesis that can make realization of a simple control strategy, in favor of an autonomous unit, is suggested for investigation. Keywords—approximate computation; signal processing; discrete cosine transform (DCT); efficient resource utilization.
Cardiovascular Activity linked to the Emotional State and Cognitive Workload during a Flight Simulation

The identification of physiological markers of emotional and cognitive fluctuations during a flight can be useful to alert of risky situations due to their possible impact on pilot’s mental state and performance. In this study, heart rate (HR) and other features, such as R-R peak interval variability and the spectral power of specific frequency bands, have been extracted from ECG recordings throughout flight simulations. The temporal variation of these features within different experimental conditions has been explored to verify their reliability to discriminate episodes of mental overload. Our results show that the monotonic decrease of HR reflects the emotional regulation, mainly under secondary low cognitive overload. Conversely, the increase of the root mean square successive differences was linked to higher cognitive workload situations. Furthermore, the habituation analysis reveals that these features are severely affected when an external cognitive demand
“We Loved It Because We Felt That We Existed There in the Classroom!”: International Students as Epistemic Equals Versus Double-Country Oppression

The article compares student narratives of engagement in internationalization in the United Kingdom and Germany. The comparison signals a new area of critical sociology of internationalization which shows signs that internationalization in non-Anglophone countries may evolve under conditions the article calls “double-country oppression. ” “Double-country oppression” denotes a situation whereby international students are put at risk of exclusion not only on the basis of lacking characteristics that “bind” them to the country of education (in this case Germany) but also, and perhaps primarily, because they lack characteristics that “bind” them to Anglophone countries, despite being located in a non-Anglophone country. As such, “double-country oppression” has important pragmatic and conceptual implications as it calls into question analytical paradigms which center around the nation-state. The emergence of “double-country oppression” also challenges the view that there are new possibilities for epistemic democracy as more non-Anglophone countries enter the internationalization competition.
Indoor Positioning System Using Accelerometry and High Accuracy Heading Sensors

The current GPS signal structure and signal power levels are barely sufficient for indoor applications. Recent developments in high sensitivity receiver technology are promising for indoor positioning inside light structures such as wooden frame houses but generally not for concrete high rise buildings. Errors due to multipath and noise associated with weak indoor signals limit the accuracy and availability of GNSS in difficult indoor environments. An alternate approach makes use of inertial technologies. However, the use of a strapdown inertial navigation system (INS) system and its traditional mechanization as a personal indoor positioning system is rather unrealistic due to the rapidly growing positioning errors caused by gyro drifts. Even a high performance INS will cause hundreds of metres of positioning error in 30 minutes without GPS updates. The majority of previously proposed personal positioning systems utilize the Pedestrian Dead Reckoning (PDR) approach. These systems use accelerometers for step detection and step length estimation and magnetic compasses or low cost gyros for heading determination. In such systems, the error sources are the step length estimation error and the heading error. Assuming no heading error, the positioning error is directly proportional to the number of steps and, thus, to the distance traveled. However, the critical component of these systems is heading. Indoor, apart from measuring the Earth’s magnetic field, magnetic sensors will be subject to other local electromagnetic fields. Over time, low cost gyros will drift in a significant and unpredictable manner which makes them unsuitable for obtaining adequate heading information. In this paper, the heading problem is resolved by using one deg/hour ring laser gyros. A tactical-grade IMU is used to provide accurate heading information, and accelerometers are used only for step occurrence detection. A special study is carried out to examine errors in heading, if only one gyro is used instead of three. In this case, the three-gyro solution is used as a reference. To test the concept, several long period tests were performed, carrying the IMU in a backpack. Both DGPS and stand-alone receivers were included to compare two different level initialization sources. 3D-gyro heading solutions initialized with DGPS are promising. However, if only one gyro is used or DGPS is not available, heading solution accuracy degrades significantly. Size restrictions on current ring laser gyros limit the application of the proposed system. However, as gyro technology evolves, such a system may be beneficial for applications such as the positioning of rescue workers, police squads, and other indoor location and navigation applications.
Interactive Teleoperation Interface for Semi-autonomous Control of Robot Arms

We propose and develop an interactive semi-autonomous control of robot arms. Our system controls two interactions: (1) A user can naturally control a robot arm by a direct linkage to the arm motion from the tracked human skeleton. (2) An autonomous image-based visual servoing routine can be triggered for precise positioning. Coarse motions are executed by human teleoperation and fine motions by image-based visual servoing. A successful application of our proposed interaction is presented for a WAM arm equipped with an eye-in-hand camera.