scholarly journals Analysis on accessibility to urban facilities using the flexible distance attenuation function

2020 ◽  
Vol 3 (3) ◽  
pp. 375-383
Author(s):  
Yusuke Kataoka
Keyword(s):  
Attenuation Function

Potential short wave attenuation function of disturbed mangroves

2020 ◽  
pp. 106747 ◽  
Author(s):  
Wei Kit Lee ◽  
Serene H.X. Tay ◽  
Seng Keat Ooi ◽  
Daniel A. Friess
Keyword(s):  
Wave Attenuation ◽  
Short Wave ◽  
Attenuation Function

A multiple-building diffraction attenuation function expressed in terms of UTD coefficients for microcellular communications

2004 ◽  
Vol 40 (4) ◽  
pp. 298-300 ◽  
Author(s):  
José-Víctor Rodríguez ◽  
José-María Molina-García-Pardo ◽  
Leandro Juan-Llácer
Keyword(s):  
Attenuation Function

Application of Site Amplification Factors to Determine the Local Magnitude from Borehole Seismic Stations in Taiwan

2020 ◽  
Author(s):  
Tz-Shin Lai ◽  
Yih-Min Wu ◽  
Wei-An Chao
Keyword(s):  
Site Effect ◽  
Site Amplification ◽  
Force Balance ◽  
Earthquake Catalog ◽  
Local Magnitude ◽  
Broadband Seismometer ◽  
Near Surface ◽  
Amplification Factors ◽  
Attenuation Function ◽  
Borehole Seismic

<p>Since the inception of 62 borehole seismic arrays deployed by Central Weather Bureau (CWB) in Taiwan until the end of 2018, a large quantity of strong-motion records have been accumulated from frequently occurring earthquakes around Taiwan, which provide an opportunity to detect micro-seismicity. Each borehole array includes two force balance accelerometers, one at the surface and other at a depth of a few ten-to-hundred (30-492) meters, as well as one broadband seismometer is below the borehole accelerometer. In general, the background seismic noise level are lower at the downhole stations than surface stations. However, the seismograms recorded by the downhole stations are smaller than surface stations due to the near-surface site effect. In Taiwan, the local magnitude (M<sub>L</sub>) determinations use the attenuation function derived from surface stations. Therefore, the M<sub>L</sub> will be underestimated by using current attenuation function for downhole stations. In this study, we used 19079 earthquakes to investigate the site amplification at subsurface materials between downhole and surface stations. Results demonstrate the amplification factors ranging from 1.11 to 5.74, provide the site effect parameter at shallow layers and have a strong relationship with Vs30. Further, we apply the amplification factors to revise the station local magnitude for downhole station. The revised M<sub>L</sub> at downhole stations correlate well with the M<sub>L</sub> at surface stations. Implement of the downhole station in the M<sub>L</sub> determination, it enhances the ability to detect the micro-earthquake and makes the earthquake catalog more comprehensive in Taiwan.</p>

scholarly journals Nitrate sources and dynamics in the salinized rivers and estuaries – a <i>δ</i><sup>15</sup>N- and <i>δ</i><sup>18</sup>O-NO<sub>3</sub><sup>–</sup> isotope approach

2014 ◽  
Vol 11 (3) ◽  
pp. 4563-4589 ◽  
Author(s):  
D. Xue ◽  
P. Boeckx ◽  
Z. Wang
Keyword(s):  
Residence Time ◽  
Water Exchange ◽  
Aerobic Denitrification ◽  
Bohai Bay ◽  
Water Residence Time ◽  
Nitrate Sources ◽  
Attenuation Function ◽  
N Source ◽  
Three Rivers

Abstract. To trace NO3– sources and assess NO3– dynamics in the salinized rivers and estuaries, three rivers (HH River, CB River and JY River) and two estuaries (HH Estuary and CJ Estuary) along the Bohai Bay (China) have been selected to determine DIN and δ15N and δ18O-NO3–. Upstream of the HH River NO3– was removed 30.9 ± 22.1% by aerobic denitrification, resulting from effects of the floodgate: limiting water exchange with downstream and prolonging water residence time to remove NO3–. Downstream of the HH River NO3– was removed 2.5 ± 13.3% by NO3– turnover processes. Conversely, NO3– was increased 36.6 ± 25.2% by external N source addition in the CB River and 34.6 ± 35.1% by in-stream nitrification in the JY River, respectively. The HH and CY Estuaries behaved mostly conservative excluding the sewage input in the CJ Estuary. Hydrodynamics in estuaries have been changed by the ongoing reclamation projects, aggravating the estuaries losing the attenuation function of NO3–.

Effect of External Calcium Concentration on the Intensity Dependence of Light-Induced Membrane Current and Voltage Signals in Two Defined States of Adaptation in the Photo-Receptor of Limulus

1986 ◽  
Vol 41 (11-12) ◽  
pp. 1092-1110 ◽  
Author(s):  
H. Stieve ◽  
H. Gaube ◽  
J. Klomfaß
Keyword(s):  
Stimulus Intensity ◽  
Time Course ◽  
Calcium Concentration ◽  
Light Adaptation ◽  
Receptor Potential ◽  
Membrane Current ◽  
Current Response ◽  
Current Signal ◽  
Intensity Dependence ◽  
Attenuation Function

Abstract The intensity dependence of the response of the Limulus ventral nerve photoreceptor to light flashes was determined in alternating measurements for the membrane current signal (receptor current) under voltage clamp conditions and the membrane voltage signal (receptor potential). Responses were obtained at two reproducible states of adaptation, while the photoreceptor was superfused by physiological saline (10 mmol/l Ca2+), or by salines with either lowered (250 μmol/l) or raised (40 mmol/l) calcium concentration. For the dark-adapted state of the photoreceptor the double logarithmic plot of the response current-time integral F (or the current amplitude) vs. flash intensity rises in a steep, supralinear section (slope 2-4) to a curve knee towards a less steep, sublinear section (slope 0.2-0.6), but does not reach saturation in the intensity range tested. Light adaptation shifts the response size vs. intensity curve towards higher light intensities. This sensitivity shift is enlarged in raised, and almost abolished in low external [Ca2+]. The changes of response latency and time-to-peak with stimulus intensity or adaptation are almost identical for receptor current and receptor potential. The decrease-time of the receptor current response, however, depends much less on the stimulus intensity or the state of adaptation than that of the receptor potential. The relative changes in the time course of the receptor current caused by light adaptation are not much influenced by variation of the [Ca2+]ex. Interpretation: The macroscopic receptor current signal consists of a volley of overlapping bumps; the size of these bumps is scaled by a calcium-dependent attenuation function which increases with delay time. This gradual growing attenuation a(t) acts as automatic gain control and may be responsible for the sublinear slope of the intensity dependence of the size of the receptor current. The supralinear slope of this dependence at lower stimulus intensities is probably caused by cooperative effects. Changes in the time course of the macroscopic receptor current due to light adaptation or varied calcium concentration are based on changes in the latency distribution of the underlying bump volley, and the size of the attenuation function.

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