scholarly journals Short-term forecast in the early stage of the COVID-19 outbreak in Italy. Application of a weighted and cumulative average daily growth rate to an exponential decay model

2020 ◽  
Author(s):  
Nicola Bartolomeo ◽  
Paolo Trerotoli ◽  
Gabriella Serio
Keyword(s):  
Growth Rate ◽  
Exponential Decay ◽  
Early Stage ◽  
Short Term ◽  
Daily Growth Rate ◽  
Daily Growth ◽  
Short Term Forecast ◽  
Term Forecast ◽  
Decay Model ◽  
Exponential Decay Model

scholarly journals Estimating the size of the COVID-19 outbreak in Italy: Application of an exponential decay model to the weighted and cumulative average daily growth rate

2020 ◽  
Author(s):  
Nicola Bartolomeo ◽  
Paolo Trerotoli ◽  
Gabriella Serio
Keyword(s):  
Growth Rate ◽  
Exponential Decay ◽  
Weighted Average ◽  
Gompertz Model ◽  
Exponential Growth Phase ◽  
Credibility Interval ◽  
Daily Growth Rate ◽  
Daily Growth ◽  
Decay Model ◽  
Exponential Decay Model

To estimate the size of the novel coronavirus (COVID-19) outbreak in Italy, this paper introduces the cumulated and weighted average daily growth rate (WR) to evaluate an epidemic curve, On the basis of an exponential decay model (EDM), we provide estimations of the WR in four-time intervals from February 27 to April 07, 2020. By calibrating the parameters of the EDM to the reported data in Hubei Province of China, we also attempt to forecast the evolution of the outbreak. We compare the EDM applied to WR and the Gompertz model, which is based on exponential decay and is often used to estimate cumulative events. Specifically, we assess the performance of each model to short-term forecast of the epidemic, and to predict the final epidemic size. Based on the official counts for confirmed cases, the model applied to data from February 27 until the 17st of March estimate that the cumulative number of infected could reach 131,280 (with a credibility interval 71,415-263,501) by April 25 (credibility interval April 12 to May 3). With the data available until the 24st of March the peak date should be reached on May 3 (April 23 to May 23) with 197,179 cumulative infections expected (130033-315,269); with data available until the 31st of March the peak should be reached on May 4 (April 25 to May 18) with 202,210 cumulative infections expected (155.235-270,737); with data available until the 07st of April the peak should be reached on May 3 (April 26 to May 11) with 191,586 (160,861-232,023) cumulative infections expected. Based on the average mean absolute percentage error (MAPE), cumulated infections forecasts provided by the EDM applied to WR performed better across all scenarios than the Gompertz model. An exponential decay model applied to the cumulated and weighted average daily growth rate appears to be useful in estimating the number of cases and peak of the COVID-19 outbreak in Italy and the model was more reliable in the exponential growth phase.

scholarly journals Public Compliance With Social Distancing Measures and SARS-CoV-2 Spread

2021 ◽  
pp. 003335492110112
Author(s):  
Hongjie Liu ◽  
Chang Chen ◽  
Raul Cruz-Cano ◽  
Jennifer L. Guida ◽  
Minha Lee
Keyword(s):  
Growth Rate ◽  
Reproduction Number ◽  
Early Stage ◽  
Human Mobility ◽  
The United States ◽  
Density Change ◽  
Regression Coefficients ◽  
Daily Growth Rate ◽  
Daily Growth ◽  
Social Distancing

Objective We quantified the association between public compliance with social distancing measures and the spread of SARS-CoV-2 during the first wave of the epidemic (March–May 2020) in 5 states that accounted for half of the total number of COVID-19 cases in the United States. Methods We used data on mobility and number of COVID-19 cases to longitudinally estimate associations between public compliance, as measured by human mobility, and the daily reproduction number and daily growth rate during the first wave of the COVID-19 epidemic in California, Illinois, Massachusetts, New Jersey, and New York. Results The 5 states mandated social distancing directives during March 19-24, 2020, and public compliance with mandates started to decrease in mid-April 2020. As of May 31, 2020, the daily reproduction number decreased from 2.41-5.21 to 0.72-1.19, and the daily growth rate decreased from 0.22-0.77 to –0.04 to 0.05 in the 5 states. The level of public compliance, as measured by the social distancing index (SDI) and daily encounter-density change, was high at the early stage of implementation but decreased in the 5 states. The SDI was negatively associated with the daily reproduction number (regression coefficients range, –0.04 to –0.01) and the daily growth rate (from –0.009 to –0.01). The daily encounter-density change was positively associated with the daily reproduction number (regression coefficients range, 0.24 to 1.02) and the daily growth rate (from 0.05 to 0.26). Conclusions Social distancing is an effective strategy to reduce the incidence of COVID-19 and illustrates the role of public compliance with social distancing measures to achieve public health benefits.

Short-term fluctuations in the live weight of identical twin cattle

1978 ◽  
Vol 27 (2) ◽  
pp. 141-146 ◽  
Author(s):  
C. S. Taylor ◽  
R. G. Griffiths ◽  
H. P. Donald
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Live Weight ◽  
Identical Twins ◽  
Identical Twin ◽  
Short Term ◽  
Daily Growth Rate ◽  
Daily Growth

ABSTRACTTwo pairs of uniformly treated identical twins were weighed four times daily for 16 days. In addition, daily growth rate was analysed for 10 pairs of identical twins kept on high and low planes of nutrition over a 16-week period.Identical twins fluctuated in body weight from hour to hour and day to day in a significantly more similar manner than did unrelated animals. The greater similarity found when all animals were uniformly treated still persisted when identical twins were placed on different planes of nutrition.

SUBSTITUSI FERMENTASI BUNGKIL KELAPA SAWIT DALAM PAKAN BUATAN TERHADAP PERTUMBUHAN DAN KELANGSUNGAN HIDUP BENIH IKAN GURAMI (OSPHRONEMUS GOURAMY)

2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Farida . ◽  
Eka Indah Raharjo ◽  
Arnis Maylinda Sari
Keyword(s):  
Growth Rate ◽  
Palm Oil ◽  
Palm Kernel ◽  
Specific Weight ◽  
Feed Conversion ◽  
Daily Growth Rate ◽  
Daily Growth ◽  
Average Growth ◽  
Fermentation Residue ◽  
Average Average

ABSTRAKPenelitian bertujuan untuk mengetahui penggunaan fermentasi bungkil kelapa sawit dalam pakan buatan.Penelitian menggunakan Rancangan Acak Lengkap (RAL) yang terdiri dari 4 perlakuan 3 ulangan.Susunan perlakuan adalah Perlakuan A : bungkil kelapa sawit 12%, Perlakuan B : fermentasi bungkil kelapa sawit 15%, Perlakuan C : fermentasi bungkil kelapa sawit 18%, Perlakuan D : fermentasi bungkil kelapa sawit 21%. Penelitian ini dilakukan selama 60 hari untuk mengetahui laju pertumbuhan spesifikberat, laju pertumbuhan harianpanjang, konversi pakan, kelangsungan hidup dan kualitas air sebagai penunjang.Hasil penelitian menunjukkan pemberian pakan buatan dengan fermentasi bungkil kelapa sawit menghasilkan respon yang baik terhadap pertumbuhan ikan gurami. Pemberian pakan buatan dengan fermentasi bungkil kelapa sawit 18% (perlakuan C), memberikan hasil terbaik dengan laju pertumbuhan dengan rata – rata laju pertumbuhan spesifik berat 1.502%, laju pertumbuhan harian panjang 4.06%, nilai konversi pakan rata – rata 3.48 dan kelangsungan hidup rata – rata 90%.Kata Kunci : Fermentasi Bungkil Kelapa Sawit, Ikan Gurami, Laju PertumbuhanThe study aims to determine the use of fermentation residue oil palm in artificial feed .Research using a completely randomized design ( CRD ), which consists of 4 treatment three replications.The composition of the treatment is the treatment  A : 12 % of palm oil cake , Treatment B : fermented palm oil cake 15 % , Treatment C : fermented palm oil cake 18 % , Treatment D : fermentation residue palm oil 21 %.This research was conducted for 60 days to determine the specific growth rate of heavy , long daily growth rate , feed conversion , survival and quality of water as a supporter.The results showed the artificial feeding with fermented palm cake to produce a good response to the growth of carp.Feeding artificially by fermentation cake palm oil 18 % ( treatment C ) , gives the best results with a growth rate with the average - average growth rate of the specific weight of 1.502 % daily growth rate long- 4:06 % , the value of feed conversion average - average 3:48 and median survival - average of 90 % .Keywords : Fermentation Palm Kernel Oil, Fish carp, Growth Rate

Tree windthrow and forest soil turnover

1989 ◽  
Vol 19 (3) ◽  
pp. 386-389 ◽  
Author(s):  
D. A. Norton
Keyword(s):  
Forest Soil ◽  
Exponential Decay ◽  
Half Life ◽  
Soil Development ◽  
Turnover Time ◽  
Important Influence ◽  
Plant Distribution ◽  
Canopy Trees ◽  
Decay Model ◽  
Exponential Decay Model

Soil turnover as a result of tree windthrow has an important influence on soil development and plant distribution in forests. Estimates of the time needed for soil turnover in a given area are often made, but unless these take into account the potential for reestablishment of canopy trees onto sites previously affected by windthrow, they are likely to substantially underestimate turnover time. Soil turnover is not a regular, uniform process, but rather results in a mosaic of soils with different turnover histories. Because soil turnover follows an exponential decay model, some area of soil will never be turned over. As it is therefore not possible to define the time when all the soil in an area has been turned over, it is proposed that soil turnover half-life (the time at which half the soil has been turned over) be used as a measure of soil turnover.

scholarly journals Principal Possibility of the Successful Nowcast and Short-Term Forecast in the Middle Atmosphere Based on the Observed UV Irradiance

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
T. Egorova ◽  
E. Rozanov ◽  
A. V. Shapiro ◽  
W. Schmutz
Keyword(s):  
Climate Model ◽  
Middle Atmosphere ◽  
Satellite Measurements ◽  
Short Term ◽  
Short Term Forecast ◽  
Atmospheric Species ◽  
Term Forecast ◽  
Uv Irradiance ◽  
Solar Uv ◽  
Solar Uv Irradiance

We have applied chemistry-climate model (CCM) SOCOL to simulate the distribution of the temperature and gas species in the upper stratosphere and mesosphere. As an input for the simulation, we employ daily spectral solar UV irradiance measured by SUSIM instrument onboard UARS satellite in January 1992. We have carried out an ensemble of nine 1-month long simulations using slightly different initial states of the atmosphere. We have compared the obtained time evolution of the simulated species and temperature with available satellite measurements. The obtained results allowed us to define the areas where the nowcast and short-term forecast of the atmospheric species with CCM SOCOL could be successful.

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