365 research outputs found

    Capital process and optimality properties of a Bayesian Skeptic in coin-tossing games

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    We study capital process behavior in the fair-coin game and biased-coin games in the framework of the game-theoretic probability of Shafer and Vovk (2001). We show that if Skeptic uses a Bayesian strategy with a beta prior, the capital process is lucidly expressed in terms of the past average of Reality's moves. From this it is proved that the Skeptic's Bayesian strategy weakly forces the strong law of large numbers (SLLN) with the convergence rate of O(\sqrt{\log n/n})$ and if Reality violates SLLN then the exponential growth rate of the capital process is very accurately described in terms of the Kullback divergence between the average of Reality's moves when she violates SLLN and the average when she observes SLLN. We also investigate optimality properties associated with Bayesian strategy

    Game-theoretic versions of strong law of large numbers for unbounded variables

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    We consider strong law of large numbers (SLLN) in the framework of game-theoretic probability of Shafer and Vovk (2001). We prove several versions of SLLN for the case that Reality's moves are unbounded. Our game-theoretic versions of SLLN largely correspond to standard measure-theoretic results. However game-theoretic proofs are different from measure-theoretic ones in the explicit consideration of various hedges. In measure-theoretic proofs existence of moments are assumed, whereas in our game-theoretic proofs we assume availability of various hedges to Skeptic for finite prices

    New procedures for testing whether stock price processes are martingales

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    We propose procedures for testing whether stock price processes are martingales based on limit order type betting strategies. We first show that the null hypothesis of martingale property of a stock price process can be tested based on the capital process of a betting strategy. In particular with high frequency Markov type strategies we find that martingale null hypotheses are rejected for many stock price processes

    Emission of polycyclic aromatic hydrocarbons (PAHs) and benzene, toluene, ethylbenzene and xylene (BTEX) from the furan moulding sands with addition of the reclaim

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    In this paper, the results of decomposition of a moulding sand with furfuryl resin also on a quartz matrix and with additions of a reclaimed material, under industrial conditions, are presented. Investigations of the gases emission in the test foundry plant were performed according to the original method developed in the Faculty of Foundry Engineering, AGH UST. The dependence of the emitted PAHs and BTEX group substances and ignition losses on the reclaim fraction in a moulding sand are of a linear character of a very high correlation coefficient R2. On the bases of the derived equations, it is possible to determine the amount of the emitted hazardous substances from the moulding sand containing the known fraction of the reclaim

    Neškodljivost kalupnih pjesaka sa bentonitom i svijetlećim nositeljima ugljika

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    Procedures have been developed to determine the volume, rate and composition (particularly BTEX: benzene, toluene, ethylbenzene and xylenes and PAHs (polycyclic aromatic hydrocarbons)) of gas evolution from moulds and cores prepared with various binders as a means of harmfulness of moulding sands. The rate of gas evolution from green sands with four different lustrous carbon carrier and BTEX content were determined. The gas evolution rates are highest in the range of about 20 to 30 s after contact with molten metal. In practice during the first 200-250 s the total emission of gases generated in investigated samples occurred. The main emitted component from the BTEX group was benzene.Postupci su razvijeni za određivanje volumena, brzine i sastava (posebice BTEX: benzen, toluen, etilbenzen, xilana) i PAH (policiklički automatski hidrokarbonati) plina koji nastaje iz kalupa i jezgri na različitim nosačima u težnji za neškodljivost kalupnih pijesaka. Brzine nastajanja plina iz pripravljenih pijesaka sa 4 različita svijetleća nositelja ugljika i sadržajem BTEX su određeni. Brzine nastajanja plina su najveće u razini 20 do 30 s poslije dodira sa rastopljenim metalom. Praktično, tijekom prvih 200-250 s ostvaruje se ukupna emisija stvorenih plinova u istraživanim uzorcima. Iz BTEX skupine, benzen je glavna emitirajuća komponenta

    Assessment of harmfulness of phenolic resins hardened by CO2 in an aspect of emission of substances from BTEX and PAH groups

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    Abstract Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. If in the initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylobenzene, xylenes), and also polycyclic aromatic hydrocarbons (PAHs) can be formed and released

    Lymph Node Characterization in Vivo Using Endoscopic Ultrasound Spectrum Analysis With Electronic Array Echo Endoscopes

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    Our purpose was to demonstrate the use of radiofrequency spectral analysis to distinguish between benign and malignant lymph nodes with data obtained using electronic array echo endoscopes, as we have done previously using mechanical echo endoscopes. In a prospective study, images were obtained from eight patients with benign-appearing lymph nodes and 11 with malignant lymph nodes, as verified by fine-needle aspiration. Midband fit, slope, intercept, correlation coefficient, and root-mean-square (RMS) deviation from a linear regression of the calibrated power spectra were determined and compared between the groups. Significant differences were observable for mean midband fit, intercept, and RMS deviation (t test P \u3c 0.05). For benign (n = 16) vs. malignant (n = 12) lymph nodes, midband fit and RMS deviation provided classification with 89 % accuracy and area under receiver operating characteristic (ROC) curve of 0.95 based on linear discriminant analysis. We concluded that the mean spectral parameters of the backscattered signals from electronic array echo endoscopy can provide a noninvasive method to quantitatively discriminate between benign and malignant lymph nodes

    Protective effect of stromal Dickkopf-3 in prostate cancer: opposing roles for TGFBI and ECM-1

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    Aberrant transforming growth factor–β (TGF-β) signaling is a hallmark of the stromal microenvironment in cancer. Dickkopf-3 (Dkk-3), shown to inhibit TGF-β signaling, is downregulated in prostate cancer and upregulated in the stroma in benign prostatic hyperplasia, but the function of stromal Dkk-3 is unclear. Here we show that DKK3 silencing in WPMY-1 prostate stromal cells increases TGF-β signaling activity and that stromal cellconditioned media inhibit prostate cancer cell invasion in a Dkk-3-dependent manner. DKK3 silencing increased the level of the cell-adhesion regulator TGF-β–induced protein (TGFBI) in stromal and epithelial cell-conditioned media, and recombinant TGFBI increased prostate cancer cell invasion. Reduced expression of Dkk-3 in patient tumors was associated with increased expression of TGFBI. DKK3 silencing reduced the level of extracellular matrix protein-1 (ECM-1) in prostate stromal cell-conditioned media but increased it in epithelial cell-conditioned media, and recombinant ECM-1 inhibited TGFBI-induced prostate cancer cell invasion. Increased ECM1 and DKK3 mRNA expression in prostate tumors was associated with increased relapse-free survival. These observations are consistent with a model in which the loss of Dkk-3 in prostate cancer leads to increased secretion of TGFBI and ECM-1, which have tumor-promoting and tumor-protective roles, respectively. Determining how the balance between the opposing roles of extracellular factors influences prostate carcinogenesis will be key to developing therapies that target the tumor microenvironment

    Hematopoietic Cells Derived from Cancer Stem Cells Generated from Mouse Induced Pluripotent Stem Cells

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    Cancer stem cells (CSCs) represent the subpopulation of cancer cells with the ability to differentiate into other cell phenotypes and initiated tumorigenesis. Previously, we reported generating CSCs from mouse induced pluripotent stem cells (miPSCs). Here, we investigated the ability of the CSCs to differentiate into hematopoietic cells. First, the primary cells were isolated from malignant tumors that were formed by the CSCs. Non-adherent cells (NACs) that arose from adherent cells were collected and their viability, as well as the morphology and expression of hematopoietic cell markers, were analyzed. Moreover, NACs were injected into the tail vein of busulfan conditioned Balb/c nude mice. Finally, CSCs were induced to differentiate to macrophages while using IL3 and SCF. The round nucleated NACs were found to be viable, positive for hematopoietic lineage markers and CD34, and expressed hematopoietic markers, just like homing to the bone marrow. When NACs were injected into mice, Wright-Giemsa staining showed that the number of white blood cells got higher than those in the control mice after four weeks. CSCs also showed the ability to differentiate toward macrophages. CSCs were demonstrated to have the potential to provide progenies with hematopoietic markers, morphology, and homing ability to the bone marrow, which could give new insight into the tumor microenvironment according to the plasticity of CSCs

    Pulsed Nonlinear Surface Acoustic Waves in Crystals

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    Abstract: Predictions from a recent theory for the propagation of nonlinear surface waves in anisotropic solids are comp~ed with measurements of laser-generated surface-wave pulses in silicon. These are the first reported comparisons of theory and experiment for the nonlinear evolution of surface waves in a crystal. THEORY AND EXPERIMENT A theoretical model was developed recently [1] that describes the propagation of plane nonlinear surface waves in anisotropic media. The spectral equations for the jth vector component (j = x, y, z) of the particle velocity in the surface wave are where x is the direction of propagation, z the coordinate normal to the traction-free surface of the solid, w the fundamental angular frequency and k the corresponding wavenurnber in the expansion; tinj (z) are eigenfunctions of the linear problem, and Rlm is a nonlinearity matrix that is known explicitly in terms of the second-and third-order elastic constants of the material. The coupled equations for Vn(x) are solved numerically, with the ad hoc absorption coefficients a~= n2Q1 intreduced for numerical stability when shocks are formed. Numerical simulations were reported for propagation in several real tryst als, and for different surface cuts and propagation directions [2]. This previous work [1,2] focused on radiation from monofrequency sources. Our purpose here is to report comparison of the theory with measurements of pulsed nonlinear surface waves in crystalline silicon. The present work thus extends an earlier comparison of theory and experiment [3] for nonlinear Rayleigh waves in an isotropic solid. Generation and detection of the surface waves were accomplished with Nd:YAG l~ers [3][4][5]. Laser radiation of wavelength 1064 nm, pulse duration 7 ns, and energy up to 50 mJ generated the surface waves. The radiation was focused with a cylindrical lens into a thin strip 6 mm by 50 pm on the surface of crystalline silicon cut along its (11 1) plane. To enhance the conversion of optical to elastic energy, a liquid layer having a large optical absorption coefficient was deposited on the surface of the silicon in the excitation region. The surface waves were detected by the deflection of a probe laser beam (diode pumped Nd:YAG, wavelength 532 nm, power 40 mW) that irradiated spots of approximately 4 pm in diameter on the surface of the silicon at distances 5 mm and 21 mm from the excitation region. The reflected probe signals were detected by two photodiodes, the output from which is proportional to the vertical velocity component v. at the surface. Surface wave pulses in these experiments had durations of 20-40 ns and peak strains of order 10-2. RESULTS Figures 1(a)-(c) show the measured waveforms and peak-normalized spectrum at distance x = 5 mm from the excitation region. Propagation of the surface wave was in the (112) direction of the (111) plane, and because of symmetry VV= O. Linear theory was used to compute the horizontal velocity VZ [1(b)] from the measured vertical velocity v= [1(a)]. The measurement at z = 5 mm was used w the starting condition for the computations, and the resulting predictions for the waveforms and spectra at z = 21 mm are shown as dashed lines i
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