10,912 research outputs found

    Relation of lineaments to sulfide deposits: Bald Eagle Mountain, Centre County, Pennsylvania

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    The author has identified the following significant results. Discrete areas of finely-fractured and brecciated sandstone float are present along the crest of Bald Mountain and are commonly sites of sulfide mineralization, as evidenced by the presence of barite and limonite gossans. The frequency distributions of the brecciated float as the negative binomial distribution supports the interpretation of a separate population of intensely fractured material. Such zones of concentrated breccia float have an average width of one kilometer with a range from 0.4 to 1.6 kilometers and were observed in a quarry face to have subvertical dips. Direct spatial correlation of the Landsat-derived lineaments to the fractured areas on the ridge is low; however, the mineralized and fracture zones are commonly assymetrical to the lineament positions. Such a systematic dislocation might result from an inherent bias in the float population or could be the product of the relative erosional resistance of the silicified material in the mineralized areas in relation to the erosionally weak material at the stream gaps

    Lineaments and Mineral Occurrences in Pennsylvania

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    The author has identified the following significant results. A conservative lineament map of Pennsylvania interpreted from ERTS-1 channel 7 (infrared) imagery and Skylab photography was compared with the distribution of known metallic mines and mineral occurrences. Of 383 known mineral occurrences, 116 show a geographical association to 1 km wide lineaments, another 24 lie at the intersection of two lineaments, and one lies at the intersection of three lineaments. The Perkiomen Creek lineament in the Triassic Basin is associated with 9 Cu-Fe occurrences. Six Pb-Zn occurrences are associated with the Tyrone-Mount Union lineament. Thirteen other lineaments are associated with 3, 4, or 5 mineral occurrences each

    Codeless GPS Applications to Multi-Path: CGAMP

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    Cordless Global Positioning System (GPS) Applications to Multi-Path (CGAMP) is meeting the challenge of exploiting the L-band signals from the Global Positioning System (GPS) satellites for the measurement of the impulse response of radio transmission channels over space-Earth paths. This approach was originally suggested by E. K. Smith and has been pursued by J. Lemmon, without an affordable implementation being identifiable. In addition to the high cost of a suitable P code correlating GPS receiver, there is also the major impediment of the often announced Department of Defense policy of selective availability/anti-spoof (SA/AS) that clouds reliable access to the wideband (20 MHz) P channel of the GPS signals without cryptographic access. A technique proposed by MacDoran utilizes codeless methods for exploiting the P channel signals implemented by the use of a pair of antennas and cross correlation signal detection

    Statistical Isotropy violation of the CMB brightness fluctuations

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    Certain anomalies at large angular scales in the cosmic microwave background measured by WMAP have been suggested as possible evidence of breakdown of statistical isotropy(SI). Most CMB photons free-stream to the present from the surface of last scattering. It is thus reasonable to expect statistical isotropy violation in the CMB photon distribution observed now to have originated from SI violation in the baryon-photon fluid at last scattering, in addition to anisotropy of the primordial power spectrum studied earlier in literature. We consider the generalized anisotropic brightness distribution fluctuations, Δ(k,n^,τ)\Delta(\vec{k}, \hat{n}, \tau) (at conformal time τ\tau) in contrast to the SI case where it is simply a function of k|\vec{k}| and k^n^\hat{k} \cdot \hat{n}. The brightness fluctuations expanded in Bipolar Spherical Harmonic (BipoSH) series, can then be written as Δ12LM(k,τ)\Delta_{\ell_1 \ell_2}^{L M}(\vec{k}, \tau) where L>0L > 0 terms encode deviations from statistical isotropy. We study the evolution of Δ12LM(k,τ)\Delta_{\ell_1 \ell_2}^{L M}(\vec{k}, \tau) from non-zero terms Δ34LM(k,τs)\Delta_{\ell_3 \ell_4}^{L M}(\vec{k}, \tau_s) at last scattering. Similar to the SI case, power at small spherical harmonic (SH) multipoles of Δ34LM(k,τs)\Delta_{\ell_3 \ell_4}^{L M}(\vec{k},\tau_s) at the last scattering, is transferred to Δ12LM(k,τ)\Delta_{\ell_1 \ell_2}^{L M}(\vec{k}, \tau) at larger SH multipoles. The structural similarity is more apparent in the asymptotic expression for large values of the final SH multipoles. This formalism allows an elegant identification of any SI violation observed today to a possible origin in the SI violation present in the baryon-photon fluid (eg., due to the presence of significant magnetic field).Comment: 14 pages, 4 figures, added illustrative example of SI violation in baryon-photon fluid, matches version accepted for publication in Phys. Rev.

    The Active Traveling Wave in the Cochlea

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    A sound stimulus entering the inner ear excites a deformation of the basilar membrane which travels along the cochlea towards the apex. It is well established that this wave-like disturbance is amplified by an active system. Recently, it has been proposed that the active system consists of a set of self-tuned critical oscillators which automatically operate at an oscillatory instability. Here, we show how the concepts of a traveling wave and of self-tuned critical oscillators can be combined to describe the nonlinear wave in the cochlea.Comment: 5 pages, 2 figure

    Economic considerations of Alzheimer's disease and related disorders

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    Economic analyses of geriatric syndromes are seldom performed. However, demographic and epidemiological imperatives have led to significant interest in the evaluation of AD-related costs. Over 300 papers devoted to economic considerations of Alzheimer's disease have been published in peer-reviewed journals, within the last five years. In these papers, the chosen perspective (costs to society or to specific payers) is important. Analytical methods are still evolving and remain complex. Unresolved methodological issues will need to be addressed to further our understanding of long-term economic consequences. At present, it is clear that diagnostic and drug costs are low compared to the major cost of institutionalization. Thus, directing efforts at early diagnosis and delaying nursing home placement are two key cost-containment interventions. In this respect, the need to support informal care should not be underestimate

    Analysis of the resistance in p-SiGe over a wide temperature range

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    The temperature dependence of a system exhibiting a `metal-insulator transition in two dimensions at zero magnetic field' (MIT) is studied up to 90K. Using a classical scattering model we are able to simulate the non-monotonic temperature dependence of the resistivity in the metallic high density regime. We show that the temperature dependence arises from a complex interplay of metallic and insulating contributions contained in the calculation of the scattering rate 1/\td(E,T), each dominating in a limited temperature range.Comment: 4 pages with 5 figure

    A Map of Update Constraints in Inductive Inference

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    We investigate how different learning restrictions reduce learning power and how the different restrictions relate to one another. We give a complete map for nine different restrictions both for the cases of complete information learning and set-driven learning. This completes the picture for these well-studied \emph{delayable} learning restrictions. A further insight is gained by different characterizations of \emph{conservative} learning in terms of variants of \emph{cautious} learning. Our analyses greatly benefit from general theorems we give, for example showing that learners with exclusively delayable restrictions can always be assumed total.Comment: fixed a mistake in Theorem 21, result is the sam
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