Predicting long-term patterns of mass loss, nitrogen dynamics, and soil organic matter formation from initial fine litter chemistry in temperate forest ecosystems

1990 ◽  
Vol 68 (10) ◽  
pp. 2201-2208 ◽  
Author(s):  
John D. Aber ◽  
Jerry M. Melillo ◽  
Charles A. McClaugherty
Keyword(s):  
Weight Loss ◽  
Organic Matter ◽  
Exponential Decay ◽  
Litter Chemistry ◽  
Litter Type ◽  
Decay Function ◽  
Carbon Fraction ◽  
Exponential Decay Function ◽  
Initial Litter Chemistry

Long-term decomposition data are presented for several types of foliar and fine root litter in different stands in Wisconsin and Massachusetts, U.S.A. Changes in mass remaining as well as nitrogen and carbon fraction (extractives, cellulose, lignin) concentration are reported. Three models were developed for describing change in mass remaining with time: a litter-specific exponential decay function (statistical fit of data for each litter type), a generalized exponential decay function (k predicted from initial litter chemistry), and a carbon fraction model that calculates the weight loss of each carbon fraction individually as a function of current carbon chemistry regardless of litter type. The exponential decay function fits all litter data well for the portion of decomposition described here, but would not be appropriate for modeling longer term decomposition. Both the generalized and carbon fraction models predicted weight loss accurately. All litter types had similar carbon fraction chemistries at the end of the first phase of decomposition described here and also exhibited a narrow range of changes in nitrogen concentration per unit weight loss. It is concluded that the length of time required to convert litter into soil organic matter and the chemistry of the material produced by this process can be predicted from initial litter chemistry and (or) relatively short-term litter decay data. Key words: immobilization, mineralization, humus, lignin, cellulose, extractives.

scholarly journals Retinal Degeneration in Choroideremia follows an Exponential Decay Function

Ophthalmology ◽  
2018 ◽  
Vol 125 (7) ◽  
pp. 1122-1124 ◽  
Author(s):  
James W. Aylward ◽  
Kanmin Xue ◽  
Maria I. Patrício ◽  
Jasleen K. Jolly ◽  
Jonathan C. Wood ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Exponential Decay ◽  
Decay Function ◽  
Exponential Decay Function

scholarly journals Experimental study of the moisture content influence on CH4 adsorption and deformation characteristics of cylindrical bituminous coal core

2018 ◽  
Vol 36 (7-8) ◽  
pp. 1512-1537 ◽  
Author(s):  
Dingyi Hao ◽  
Lei Zhang ◽  
Mingxue Li ◽  
Shihao Tu ◽  
Cun Zhang ◽  
...  
Keyword(s):  
Moisture Content ◽  
Adsorption Capacity ◽  
Exponential Decay ◽  
Coal Mine ◽  
Bituminous Coal ◽  
Gas Adsorption ◽  
Decay Function ◽  
Exponential Decay Function ◽  
Adsorption Deformation ◽  
Original Moisture

Moisture content in coal is an important factor affecting the coal seam gas extraction. It directly affects the storage and flow of gas in bituminous coal. In this paper, the cylindrical bituminous coal cores of Xutuan coal mine in Huaibei coal mine group were studied as experimental objects, using the laboratory self-designed experimental device Gas Adsorption and Strain Testing Apparatus system. The influence of the bituminous coal moisture content on gas adsorption characteristics was studied. Drying experiments of coal samples showed that they lose the original moisture content following the exponential decay function of time. At wetting, the saturated moisture content in coal samples increased following the Exponential Association function of time. The experimental results show that the average original moisture content and average saturated moisture content of raw coal samples are 1.3 and 2.4%, respectively. On this basis, the gas adsorption experiments on samples with different moisture contents under different gas pressures were carried out. With the moisture content increase, the gas adsorption capacity and saturation value decreased and the decrease rate gradually reduced. The single exponential decay function describes the gas adsorption capacity dependence on moisture content. Moisture content also affects the adsorption deformation of bituminous coal. At high moisture content, the adsorption deformation of bituminous coal is less.

Time resolved fluorescence of aqueous tryptophan

1978 ◽  
Vol 56 (5) ◽  
pp. 743-745 ◽  
Author(s):  
D. M. Rayner ◽  
A. G. Szabo
Keyword(s):  
Exponential Decay ◽  
Emission Spectra ◽  
Fluorescence Decay ◽  
Time Resolved Fluorescence ◽  
Decay Function ◽  
Time Resolved ◽  
Exponential Decay Function

The fluorescence decay of aqueous tryptophan is shown to be described by a two exponential decay function whose components have life-times of 3.14 ns and 0.51 ns. These components are assigned as the solvent equilibrated 1La and 1Lb, states respectively. The time-resolved emission spectra are presented and can be resolved into two spectra with λmax at 350 nm and 335 nm corresponding to these two states.

A new method of determining brightness and size of cometary nuclei

2020 ◽  
Vol 492 (3) ◽  
pp. 4175-4188 ◽  
Author(s):  
Mieczyslaw Leszek Paradowski
Keyword(s):  
Bulk Density ◽  
Exponential Decay ◽  
Linear Dependence ◽  
New Method ◽  
Nuclear Density ◽  
Decay Function ◽  
Cometary Nuclei ◽  
Exponential Decay Function ◽  
Visual Magnitude ◽  
The Mean

ABSTRACT This paper presents a new method of determining the brightness and size of cometary nuclei that has been applied to the following 32 observed comets: 2P/Encke, 29P/Schwassmann-Wachmann 1, 102P/Shoemaker 1, 103P/Hartley 2, 168P/Hergenrother, 189P/NEAT, 260P/McNaught, 315P/LONEOS, P/2012 NJ (La Sagra), P/2013 J2 (McNaught), C/2006 S3 (LONEOS), C/2009 P1 (Garradd), C/2010 S1 (LINEAR), C/2010 X1 (Elenin), C/2011 J2 (LINEAR), C/2011 L4 (PANSTARRS), C/2011 W3 (Lovejoy), C/2012 F6 (Lemmon), C/2012 J1 (Catalina), C/2012 K1 (PANSTARRS), C/2012 S1 (ISON), C/2013 R1 (Lovejoy), C/2013 US10 (Catalina), C/2014 B1 (Schwartz), C/2014 E2 (Jacques), C/2014 Q2 (Lovejoy), C/2015 F4 (Jacques), C/2015 V2 (Johnson), C/2015 ER61 (PANSTARRS), C/2015 VL62 (Lemmon-Yeung-PANSTARRS), C/2016 A8 (LINEAR), and C/2017 O1 (ASASSN). The method consists in fitting the exponential decay function to the measured coma brightness in the aperture radius range from 0.5 to 2 pixels, and extrapolating this function to 0 pixels to obtain nuclear brightness. The R-band absolute nuclear magnitude RN(1, 1, 0), and the logarithm of the nucleus diameter DN expressed in kilometres, follow a linear dependence with the absolute total visual magnitude H. This dependence is of the form RN(1, 1, 0) = 12.5943 + 0.648H, and log DN[km] = 1.2415 − 0.13H. Comet 2P/Encke does not fit this dependence due to its high nuclear density of 800 kg m−3 (Sosa & Fernández 2009). The mean bulk density of the observed comets (except 2P/Encke) is 453 ± 29 kg m−3. The accuracy of the method in determining the brightness of comet nuclei at a level of 1σ is 8 per cent.

Modeling Treatment Response to Transcranial Magnetic Stimulation Using an Exponential Decay Function

2021 ◽  
Vol 89 (9) ◽  
pp. S195-S196
Author(s):  
Yosef Berlow ◽  
Amin Zandvakili ◽  
Lawrence Price ◽  
Noah Philip
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Treatment Response ◽  
Exponential Decay ◽  
Magnetic Stimulation ◽  
Decay Function ◽  
Exponential Decay Function

Lack of Effect of Stimulant and Depressant Drugs on Spiral Aftereffect

1967 ◽  
Vol 24 (3_suppl) ◽  
pp. 1263-1270 ◽  
Author(s):  
Thomas R. Scott ◽  
Robert A. Bragg ◽  
Augustus E. Jordan
Keyword(s):  
Motion Perception ◽  
Exponential Decay ◽  
Visual Motion ◽  
Motion Aftereffect ◽  
Neural Systems ◽  
Decay Function ◽  
Neuron Firing ◽  
Actual Measurement ◽  
Visual Motion Perception ◽  
Exponential Decay Function

Eysenck's claim that sodium amytal shortens and dexedrine lengthens the duration of spiral aftereffect was not borne out in any of four experiments designed to demonstrate it, including a replication of his study. A further replication, different only in the stimulus used, yielded no effect of amytal or dexedrine. Actual measurement of aftereffect rate immediately following the eliciting stimulus and after selected delays showed an exponential decay function for aftereffect rate but did not demonstrate any effect of the two drugs. This repeated failure to demonstrate a change in aftereffect as a result of the administration of drugs known to affect neuron firing thresholds has implications for the understanding of neurophysiology of visual motion perception. It was proposed that motion aftereffect is based on a comparison of the states of two neural systems both of which are equally affected by the drugs.

Sign in / Sign up

Export Citation Format

Share Document