17,346 research outputs found

    The Behavior of Money, Credit, and Prices in a Real Business Cycle

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    This paper analyzes the interaction of money and the price level with a business cycle that is fully real in origin, adopting a view which differs sharply from traditional theories that assign a significant causal influence to monetary movements. The theoretical analysis focuses on a banking system that produces transaction. services on demand and thus reflects market activity. Under one regime of bank regulation and fiat money supply by the monetary authority, the real business cycle theory predicts that (i)movements in external monetary measures should be uncorrelated with real activity and(ii) movements in internal monetary measures should be positively correlated with real activity. Preliminary empirical analysis provides general support for this focus on the banking sector since much of the correlation between monetary measures and real activity is apparently with inside money.

    Frequency Of Isolation Of Salmonella From Commercial Poultry Feeds And Their Anti-Microbial Resistance Profiles, Imo State, Nigeria

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    This study was conducted to determine the frequency of isolation of salmonella and their microbial resistance profiles across different commercial poultry feeds sold in Imo State, Nigeria. Thirty-six bulk feed samples were colleted from 154 bag across different feed types and brands which included Guinea (GF), Top (TF), Vital (VF), Extra (EF), Animal care (AF) and livestock (LF) feeds. The salmonella isolated were tested against 14 anti-microbial drugs using the disc diffusion method. Bacterial load enumeration of the samples indicated a range of <30 colony forming unit (CFU) to overgrowth at 104 serial dilutions. Eight feed samples (22.2%) which cuts across the entire feed brands expect EF were positive for salmonella. The highest prevalence of 28.8% and 25.0% were recorded for LF and TF respectively, while VF, GF and AF had 11.1 and 10.0% respectively. Salmonella isolates showed high rates of resistance (51-100%) against nitrofurantoin, ampicillin, tetracycline and ceftriazole, while moderate rates (31-50%) were recorded for chloramphenicol, oxfloxacin and cotrimoxazole. Low resistance rates (1-30%) were on the other hand recorded against ciprofloxacin and amoxycillin clavulanate (Augumentine), whereas zero resistance was demonstrated against pefloxacin, gentamycin, streptomycin and nalidixic. Commercial feeds form important channels for the dissemination of multi-drug resistant salmonella in Imo State, Nigeria

    On-chip cavity quantum phonodynamics with an acceptor qubit in silicon

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    We describe a chip-based, solid-state analogue of cavity-QED utilizing acoustic phonons instead of photons. We show how long-lived and tunable acceptor impurity states in silicon nanomechanical cavities can play the role of a matter non-linearity for coherent phonons just as, e.g., the Josephson qubit plays in circuit-QED. Both strong coupling (number of Rabi oscillations ~ 100) and strong dispersive coupling (0.1-2 MHz) regimes can be reached in cavities in the 1-20 GHz range, enabling the control of single phonons, phonon-phonon interactions, dispersive phonon readout of the acceptor qubit, and compatibility with other optomechanical components such as phonon-photon translators. We predict explicit experimental signatures of the acceptor-cavity system.Comment: 6 pages, 2 figures, PDFLaTeX. New version improves clarit

    Stochastic Trends and Economic Fluctuations

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    Recent developments in macroeconomic theory emphasize that transient economic fluctuations can arise as responses to changes in long run factors -- in particular, technological improvements -- rather than short run factors. This contrasts with the view that short run fluctuations and shifts in long run trends are largely unrelated. We examine empirically the effect of shifts in stochastic trends that are common to several macroeconomic series. Using a linear time series model related to a VAR, we consider first a system with GNP, consumption and investment with a single common stochastic trend; we then examine this system augmented by money and prices and an additional stochastic trend. Our results suggest that movements in the "real" stochastic trend account for one-half to two-thirds of the variation in postwar U.S. GNP.

    B-> rho pi, rho rho, pi pi: hunting for alpha

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    We determine the domains of the values of unitarity triangle angle alpha, allowed by the charmless strangeless B_d (\bar B_d) decays.Comment: 16 pages. Recent Belle results on CP asymmetries in B_d(\bar{B}_d)-->rho^+ rho^- decays are taken into account. Version to be published in Yad.Fi

    Topological entropy of realistic quantum Hall wave functions

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    The entanglement entropy of the incompressible states of a realistic quantum Hall system are studied by direct diagonalization. The subdominant term to the area law, the topological entanglement entropy, which is believed to carry information about topologic order in the ground state, was extracted for filling factors 1/3, 1/5 and 5/2. The results for 1/3 and 1/5 are consistent with the topological entanglement entropy for the Laughlin wave function. The 5/2 state exhibits a topological entanglement entropy consistent with the Moore-Read wave function.Comment: 6 pages, 6 figures; improved computations and graphics; added reference

    A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: The Group Catalog

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    With a large, unique spectroscopic survey in the fields of 28 galaxy-scale strong gravitational lenses, we identify groups of galaxies in the 26 adequately-sampled fields. Using a group finding algorithm, we find 210 groups with at least five member galaxies; the median number of members is eight. Our sample spans redshifts of 0.04 zgrp\le z_{grp} \le 0.76 with a median of 0.31, including 174 groups with 0.1<zgrp<0.60.1 < z_{grp} < 0.6. Groups have radial velocity dispersions of 60 σgrp\le \sigma_{grp} \le 1200 km s1^{-1} with a median of 350 km s1^{-1}. We also discover a supergroup in field B0712+472 at z=z = 0.29 consisting of three main groups. We recover groups similar to \sim 85% of those previously reported in these fields within our redshift range of sensitivity and find 187 new groups with at least five members. The properties of our group catalog, specifically 1) the distribution of σgrp\sigma_{grp}, 2) the fraction of all sample galaxies that are group members, and 3) the fraction of groups with significant substructure, are consistent with those for other catalogs. The distribution of group virial masses agrees well with theoretical expectations. Of the lens galaxies, 12 of 26 (46%) (B1422+231, B1600+434, B2114+022, FBQS J0951+2635, HE0435-1223, HST J14113+5211, MG0751+2716, MGJ1654+1346, PG 1115+080, Q ER 0047-2808, RXJ1131-1231, and WFI J2033-4723) are members of groups with at least five galaxies, and one more (B0712+472) belongs to an additional, visually identified group candidate. There are groups not associated with the lens that still are likely to affect the lens model; in six of 25 (24%) fields (excluding the supergroup), there is at least one massive (σgrp\sigma_{grp} \ge 500 km s1^{-1}) group or group candidate projected within 2^{\prime} of the lens.Comment: 87 pages, 8 figures, a version of this was published in Ap

    ASSESSING SENIOR SECONDARY STUDENTS’ KNOWLEDGE OF BASIC MATHEMATICAL SKILLS AND ALGEBRA

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    This study assessed the extent of the senior secondary students’ knowledge of basic mathematical skills and algebrainObio/Akpor Local Government Area (LGA) of Rivers State, Nigeria. Four research questions and four hypotheses guided the study. A minimum sample of 400 students obtained from a population of 18,087 using Taro Yamane formula was selected by simple random sampling. Basic Mathematical Skills Test (BMST) and Algebra Performance Test (APT) were used for data collection. The instruments were validated by experts in Mathematics Education while their reliabilities were established using test-retest method. The reliability coefficients of 0.74 and 0.78 were obtained for BMST and APT respectively by correlating the test and re-test scores of BMST and APT using the Pearson product moment correlation. Mean and standard deviation were used to answer the research questions while sample t-test and analysis of variance (ANOVA) were used to test the hypotheses at 0.05 significant level. Major result of the study showed that students’ knowledge of basic mathematical skills and algebra is significantly high. The result also revealed that the differences in the male and the female students’ knowledge of basic mathematical skills and algebra were not significant respectively. It was recommended among others that the current instructional process and practice in Mathematics at the basic and senior secondary education levels should be sustained and instead improved upon by the Mathematics teachers.  Article visualizations

    Transformation Properties of External Radiation Fields, Energy-Loss Rates and Scattered Spectra, and a Model for Blazar Variability

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    We treat transformation properties of external radiation fields in the proper frame of a plasma moving with constant speed. The specific spectral energy densities of external isotropic and accretion-disk radiation fields are derived in the comoving frame of relativistic outflows, such as those thought to be found near black-hole jet and gamma-ray burst sources. Nonthermal electrons and positrons Compton-scatter this radiation field, and high-energy protons and ions interact with this field through photomeson and photopair production. We revisit the problem of the Compton-scattered spectrum associated with an external accretion-disk radiation field, and clarify a past treatment by the authors. Simple expressions for energy-loss rates and Thomson-scattered spectra are given for ambient soft photon fields consisting either of a surrounding external isotropic monochromatic radiation field, or of an azimuthally symmetric, geometrically thin accretion-disk radiation field. A model for blazar emission is presented that displays a characteristic spectral and variability behavior due to the presence of a direct accretion-disk component. The disk component and distinct flaring behavior can be bright enough to be detected from flat spectrum radio quasars with {\it GLAST}. Spectral states of blazars are characterized by the relative importance of the accretion-disk and scattered radiation fields and, in the extended jet, by the accretion disk, inner jet, and cosmic microwave background radiation fields.Comment: 43 pages, 12 figures, ApJ, in press; includes improvements in response to referee report, added references, section of detectability with GLAS
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