10,539 research outputs found
Normalizers of tori
We determine the groups which can appear as the normalizer of a maximal torus
in a connected 2-compact group. The technique depends on using ideas of Tits to
give a novel description of the normalizer of the torus in a connected compact
Lie group, and then showing that this description can be extended to the
2-compact case.Comment: Published by Geometry and Topology at
http://www.maths.warwick.ac.uk/gt/GTVol9/paper31.abs.htm
The News in Financial Asset Returns
The notion that financial asset returns are predictors of future economic activity is widespread, but detailed analyses provide little support for financial markets ability to reveal future economic activity. Even though the evidence on various indicators used by different researchers is mixed, the authors of this article explore the notion that financial markets reveal useful information about future economic activity. This article examines and answers two questions: First, what is a good way of extracting information about future economic activity from asset prices? Second, do financial asset returns help predict economic activity over horizons from one month to five years? To determine whether news of an assets excess return can reveal information about unexpected economic activity, the authors construct a method of extracting the news about future economic activity from returns on financial assets. The authors use linear regressions to relate the unexpected parts of economic activity and the assets return to actual economic activity and the actual return on an asset. The evidence in the article shows that movements in financial markets do presage developments in the economy. The authors find that movements in the overall stock market and bond returns are the most important financial indicators. It remains to be seen whether those indicators hold up to variations in technique or the passage of time
Finiteness in derived categories of local rings
New homotopy invariant finiteness conditions on modules over commutative
rings are introduced, and their properties are studied systematically. A number
of finiteness results for classical homological invariants like flat dimension,
injective dimension, and Gorenstein dimension, are established. It is proved
that these specialize to give results concerning modules over complete
intersection local rings. A noteworthy feature is the use of techniques based
on thick subcategories of derived categories.Comment: 40 pages. Minor revisions. To appear in Commentarii Math. Helvetic
Branching, holding companies, and banking concentration in the Eighth District
Federal Reserve District, 8th ; Financial institutions
Constraints on θ_(13) from a three-flavor oscillation analysis of reactor antineutrinos at KamLAND
We present new constraints on the neutrino oscillation parameters Δm^2_(21), θ_(12), and θ_(13) from a three flavor
analysis of solar and KamLAND data. The KamLAND data set includes data acquired following a radiopurity upgrade and amounts to a total exposure of 3.49 x 10^(32) target-proton-year. Under the assumption of CPT invariance, a two-flavor analysis (θ_(13) = 0) of the KamLAND and solar data yields the best-fit values tan^2θ_(12) = 0.444^(+0.036)_(-0.030) and Δm^2_(21) = 7.50^(+0.19)_(-0.20) x 10^(-5) eV^2; a three-flavor analysis with θ13 as a free parameter yields the best-fit values tan^2θ_(12) = 0.452^(+0.035)_(-0.033), Δm^2_(21) = 7.50^(+0.19)_(-0.20) x 10^(-5) eV^2, and sin^2θ_(13) = 0.020^(+0.016)_(-0.016). This θ_(13) interval is consistent with other recent work combining the CHOOZ, atmospheric and long-baseline accelerator experiments. We also present a new global θ_(13) analysis, incorporating the CHOOZ, atmospheric, and accelerator data, which indicates sin^2θ_(13) = 0.009^(+0.013)-_(0.007). A nonzero value is suggested, but only at the 79% C.L
Measurement of the ^8B solar neutrino flux with the KamLAND liquid scintillator detector
We report a measurement of the neutrino-electron elastic scattering rate from ^8B solar neutrinos based on a 123 kton-day exposure of KamLAND. The background-subtracted electron recoil rate, above a 5.5-MeV analysis threshold is 1.49 ± 0.14(stat) ± 0.17(syst) events per kton-day. Interpreted as due to a pure electron flavor flux with a ^8B neutrino spectrum, this corresponds to a spectrum integrated flux of 2.77 ± 0.26(stat) ± 0.32(syst) ×10^6 cm^(−2_s^(−1). The analysis threshold is driven by ^(208)Tl present in the liquid scintillator, and the main source of systematic uncertainty is due to background from cosmogenic ^(11)Be. The measured rate is consistent with existing measurements and with standard solar model predictions which include matter-enhanced neutrino oscillation
DG algebras with exterior homology
We study differential graded algebras whose homology is an exterior algebra
over a commutative ring R on a generator of degree n, and also certain types of
differential modules over these DGAs. We obtain a complete classification when
R is the integers, or the prime field of characteristic p>0, and n is greater
than or equal to -1. The examples are unexpectedly interesting.Comment: 15 page
Partial radiogenic heat model for Earth revealed by geoneutrino measurements
The Earth has cooled since its formation, yet the decay of radiogenic isotopes, and in particular uranium, thorium and
potassium, in the planet’s interior provides a continuing heat source. The current total heat flux from the Earth to space is 44:2±1.0 TW, but the relative contributions from residual primordial heat and radiogenic decay remain uncertain. However, radiogenic decay can be estimated from the flux of geoneutrinos, electrically neutral particles that are emitted during radioactive decay and can pass through the Earth virtually unaffected. Here we combine precise measurements of the geoneutrino flux from the Kamioka Liquid-Scintillator Antineutrino Detector, Japan, with existing measurements from the Borexino detector, Italy.We find that decay of uranium-238 and thorium-232 together contribute 20.0^(+8.8)_(-8.6)TW to Earth’s heat
flux. The neutrinos emitted from the decay of potassium-40 are below the limits of detection in our experiments, but are known to contribute 4TW. Taken together, our observations indicate that heat from radioactive decay contributes about half of Earth’s total heat flux. We therefore conclude that Earth’s primordial heat supply has not yet been exhausted
Production of radioactive isotopes through cosmic muon spallation in KamLAND
Radioactive isotopes produced through cosmic muon spallation are a background for rare-event detection in ν detectors, double-β-decay experiments, and dark-matter searches. Understanding the nature of cosmogenic backgrounds is particularly important for future experiments aiming to determine the pep and CNO solar neutrino fluxes, for which the background is dominated by the spallation production of ^(11)C. Data from the Kamioka liquid-scintillator antineutrino detector (KamLAND) provides valuable information for better understanding these backgrounds, especially in liquid scintillators, and for checking estimates from current simulations based upon MUSIC, FLUKA, and GEANT4. Using the time correlation between detected muons and neutron captures, the neutron production yield in the KamLAND liquid scintillator is measured to be Y_n=(2.8±0.3)×10^(-4) μ^(-1) g^(-1) cm^2. For other isotopes, the production yield is determined from the observed time correlation related to known isotope lifetimes. We find some yields are inconsistent with extrapolations based on an accelerator muon beam experiment
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