863 research outputs found

    How to Fix Coordination Lags in the Keynesian Macroeconomical Intervention?

    Get PDF
    The Keynesian macroecomic intervention often fails. This is most likely due to forecasting problems of the macroeconomy. This article present a software idea of fuzzy logic controlling unit which replaces long and tedious human intervention in macroeconomic stimulation process. The Keynesian Macroeconomic intervention now made by officials and politicians is suggested to be made by much faster and more purposeful automatic computer adjustment process. It is assumed that this kind of just in time and very fast automatic computer intervention would lead to optimimal usage of the resources in a much better way than any current human lead  systems would be able to do.

    The role of luck at Wall Street: What if I told you that Warren Buffet is merely lucky

    Get PDF
    Tämä pro gradu työ etsii tuurin merkitystä sijoitustoiminnassa. Työ juontaa aiheensa siitä väittämästä, että markkina indeksien käyttäytymistä voidaan kuvailla humalaisen ihmisen satunnaiskävelyllä. Koskaan et siis voi olla täysin varma, ottaako humalainen askeleen oikealle vai vasemmalle vai pysyykö yhtäkkisesti paikoillaan. Samalla tavalla voidaan ns. Random walk hypoteesin vallitessa katsoa, että pörssi-indeksi joko nousee, laskee tai pysyy paikoillaan ennalta arvaamattomasti kuin vedonlyönti rulettipöydän ääressä kasinolla. Näin ollen voidaan kauaskantoisesti olettaa, että on olemassa vain tuurilla menestykseen nousseita osakesuursijoittajia, koska sijoitustaidolla ei ole Eugene Faman tehokkaiden markkinoiden hypoteesin vallitessa mitään käytännön merkitystä. Nobelisti Eugene Faman mukaan fundamentalistianalyysilla tai teknisellä analyysillä ei pitäisi olla mitään käytännön merkitystä kenellekään sijoittajalle. Random walk - hypoteesi nauttii akateemisissa piireissä suurehkoa luottamusta. This master's thesis looks for the meaning of luck in investment activities. The work derives its subject from the claim that the behavior of market indices can be described as that of a drunk person on a random walk. So you can never be entirely sure whether a drunk man will take a step to the right or the left or does it suddenly stay still. Thus, it can be assumed that luck can explain successful stock investors' big incomes

    The role of electron-hole recombination in organic magnetoresistance

    Full text link
    Magneto-electrical measurements were performed on diodes and bulk heterojunction solar cells (BHSCs) to clarify the role of formation of coulombically bound electron-hole (e-h) pairs on the magnetoresistance (MR) response in organic thin film devices. BHSCs are suitable model systems because they effectively quench excitons but the probability of forming e-h pairs in them can be tuned over orders of magnitude by the choice of material and solvent in the blend. We have systematically varied the e-h recombination coefficients, which are directly proportional to the probability for the charge carriers to meet in space, and found that a reduced probability of electrons and holes meeting in space lead to disappearance of the MR. Our results clearly show that MR is a direct consequence of e-h pair formation. We also found that the MR line shape follows a power law-dependence of B0.5 at higher fields

    A 2D Quantum Walk Simulation of Two-Particle Dynamics

    Full text link
    Multi-dimensional quantum walks can exhibit highly non-trivial topological structure, providing a powerful tool for simulating quantum information and transport systems. We present a flexible implementation of a 2D optical quantum walk on a lattice, demonstrating a scalable quantum walk on a non-trivial graph structure. We realized a coherent quantum walk over 12 steps and 169 positions using an optical fiber network. With our broad spectrum of quantum coins we were able to simulate the creation of entanglement in bipartite systems with conditioned interactions. Introducing dynamic control allowed for the investigation of effects such as strong non-linearities or two-particle scattering. Our results illustrate the potential of quantum walks as a route for simulating and understanding complex quantum systems

    Heavy-Light Semileptonic Decays in Staggered Chiral Perturbation Theory

    Full text link
    We calculate the form factors for the semileptonic decays of heavy-light pseudoscalar mesons in partially quenched staggered chiral perturbation theory (\schpt), working to leading order in 1/mQ1/m_Q, where mQm_Q is the heavy quark mass. We take the light meson in the final state to be a pseudoscalar corresponding to the exact chiral symmetry of staggered quarks. The treatment assumes the validity of the standard prescription for representing the staggered ``fourth root trick'' within \schpt by insertions of factors of 1/4 for each sea quark loop. Our calculation is based on an existing partially quenched continuum chiral perturbation theory calculation with degenerate sea quarks by Becirevic, Prelovsek and Zupan, which we generalize to the staggered (and non-degenerate) case. As a by-product, we obtain the continuum partially quenched results with non-degenerate sea quarks. We analyze the effects of non-leading chiral terms, and find a relation among the coefficients governing the analytic valence mass dependence at this order. Our results are useful in analyzing lattice computations of form factors B→πB\to\pi and D→KD\to K when the light quarks are simulated with the staggered action.Comment: 53 pages, 8 figures, v2: Minor correction to the section on finite volume effects, and typos fixed. Version to be published in Phys. Rev.

    No SMAD4 hypermethylation in colorectal cancer

    Get PDF
    The chromosome region 18q21 is frequently deleted in colorectal cancers. Three candidate tumour suppressor genes, DCC, SMAD4 and SMAD2, map to this region. The SMAD4(DPC4) gene was recently identified as a candidate pancreatic cancer suppressor gene. It is also a gene for juvenile polyposis tumour predisposition syndrome. Somatic SMAD4 mutations have been detected in some colorectal carcinomas. However, the frequency of these mutations is relatively low, and whether SMAD4 plays a key role in colorectal tumorigenesis is still unclear. In addition to loss of chromosomal material and intragenic mutations there is a third mechanism, DNA methylation, which may have an important role in gene inactivation. In the present study, we examined whether promoter hypermethylation could be a mechanism for SMAD4 inactivation. In total, 42 colorectal tumours were selected for the methylation analysis and no evidence of promoter hypermethylation was found. Our result suggests that hypermethylation of the SMAD4 promoter region is not a frequent event in colorectal tumorigenesis. © 2000 Cancer Research Campaig

    The Ammount of Interstellar Carbon Locked in Solid Hydrogenated Amorphous Carbon

    Full text link
    We review the literature and present new experimental data to determine the amount of carbon likely to be locked in form of solid hydrogenated amorphous carbon (HAC) grains. We conclude on the basis of a thorough analysis of the intrinsic strength of the C-H stretching band at 3.4 micron that between 10 and 80 ppM H of carbon is in the form of HAC grains. We show that it is necessary to know the level of hydrogenation (H/C) of the interstellar HAC to determine more precisely the amount of carbon it ties up. We present optical constants, photoluminescence spectroscopy, and IR absorption spectroscopy for a particular HAC sample that is shown to have a 3.4 micron absorption feature that is quantatively consistent with that observed in the diffuse interstellar medium.Comment: This paper is 14 pages long with 5 figures and will appear in the 1 December 1999 issue of Ap

    Experimental study of magneto-superconductor RuSr2Eu1.5Ce0.5Cu2O10: Effect of Mo doping on magnetic behavior and Tc variation

    Get PDF
    Mo doped ruthenocuprates Ru1-xMoxSr2Eu1.5Ce0.5Cu2O10 are synthesized for x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0, and their magnetic and superconducting properties are studied. It has been found that the magnetic transition temperature TZFCpeak, which corresponds to the appearance of weak ferromagnetic effect, decreases from its value of 75 K for x = 0.0 to 22 K, 25 K and 18 K, respectively for the x = 0.2, 0.4 and 0.6 samples. Another finding is that the magnetic susceptibility reduces at TZFCpeak by a factor of about 6, 85 and 413 for x = 0.2, 0.4, and 0.6 respectively. The samples of x = 0.8 and 1.0 are found to have no magnetic or superconducting effects. The values of the superconducting transition temperature are obtained from the resistivity versus temperature data. An important result is that Tc increases by 4.5 K and 7.0 K for x = 0.2 and 0.4 respectively, and then decreases by 17 K for x = 0.6. The observed variation of Tc with x has been explained in terms of a theory which combines the effects of weakening magnetic behavior and reducing carrier concentration in a phenomenological manner. The resulting theory is found to provide a good agreement with the observed value of Tc.Comment: 14 pages with Text + Figs. To Appear in PHYS. REV. B, Ist Jan. 2006 issu

    Accessing the purity of a single photon by the width of the Hong-Ou-Mandel interference

    Full text link
    We demonstrate a method to determine the spectral purity of single photons. The technique is based on the Hong-Ou-Mandel (HOM) interference between a single photon state and a suitably prepared coherent field. We show that the temporal width of the HOM dip is not only related to reciprocal of the spectral width but also to the underlying quantum coherence. Therefore, by measuring the width of both the HOM dip and the spectrum one can directly quantify the degree of spectral purity. The distinct advantage of our proposal is that it obviates the need for perfect mode matching, since it does not rely on the visibility of the interference. Our method is particularly useful for characterizing the purity of heralded single photon states.Comment: Extended version, 16 pages, 9 figure
    • …
    corecore