Publications by R on The broken bridge between biologists and statisticians
Self-starting routines for nonlinear regression models
In R, the drc package represents one of the main solutions for nonlinear regression and dose-response analyses (Ritz et al., 2015). It comes with a lot of nonlinear models, which are useful to describe several biological processes, from plant growth to bioassays, from herbicide degradation to seed germination. These models are provided with self-...
6835 sym R (3482 sym/10 pcs) 4 img
A collection of self-starters for nonlinear regression in R
Usually, the first step of every nonlinear regression analysis is to select the function \(f\), which best describes the phenomenon under study. The next step is to fit this function to the observed data, possibly by using some sort of nonlinear least squares algorithms. These algorithms are iterative, in the sense that they start from some initi...
27302 sym R (11048 sym/21 pcs) 28 img
A collection of self-starters for nonlinear regression in R
Usually, the first step of every nonlinear regression analysis is to select the function \(f\), which best describes the phenomenon under study. The next step is to fit this function to the observed data, possibly by using some sort of nonlinear least squares algorithms. These algorithms are iterative, in the sense that they start from some initi...
27302 sym R (11048 sym/21 pcs) 28 img
Seed germination: fitting hydro-time models with R
I am locked at home, due to the COVID-19 emergency in Italy. Luckily I am healthy, but there is not much to do, inside. I thought it might be nice to spend some time to talk about seed germination models and the connections with survival analysis. We all know that seeds need water to germinate. Indeed, the absorption of water activates the hydrol...
18108 sym R (4937 sym/13 pcs) 4 img
Seed germination: fitting hydro-time models with R
I am locked at home, due to the COVID-19 emergency in Italy. Luckily I am healthy, but there is not much to do, inside. I thought it might be nice to spend some time to talk about seed germination models and the connections with survival analysis. We all know that seeds need water to germinate. Indeed, the absorption of water activates the hydrol...
18108 sym R (4937 sym/13 pcs) 4 img
Seed germination: fitting hydro-time models with R
I am locked at home, due to the COVID-19 emergency in Italy. Luckily I am healthy, but there is not much to do, inside. I thought it might be nice to spend some time to talk about seed germination models and the connections with survival analysis. We all know that seeds need water to germinate. Indeed, the absorption of water activates the hydrol...
18108 sym R (4937 sym/13 pcs) 4 img
AMMI analyses for GE interactions
The CoViD-19 situation in Italy is little by little improving and I feel a bit more optimistic. It’s time for a new post! I will go back to a subject that is rather important for most agronomists, i.e. the selection of crop varieties. All farmers are perfectly aware that crop performances are affected both by the genotype and by the environmen...
17034 sym R (9269 sym/17 pcs) 2 img
AMMI analyses for GE interactions
The CoViD-19 situation in Italy is little by little improving and I feel a bit more optimistic. It’s time for a new post! I will go back to a subject that is rather important for most agronomists, i.e. the selection of crop varieties. All farmers are perfectly aware that crop performances are affected both by the genotype and by the environmen...
17034 sym R (9269 sym/17 pcs) 2 img
Fitting complex mixed models with nlme. Example #5
A Joint Regression model Let’s talk about a very old, but, nonetheless, useful technique. It is widely known that the yield of a genotype in different environments depends on environmental covariates, such as the amount of rainfall in some critical periods of time. Apart from rain, also temperature, wind, solar radiation, air humidity and soil ...
11662 sym R (9136 sym/9 pcs) 2 img
Fitting complex mixed models with nlme. Example #5
A Joint Regression model Let’s talk about a very old, but, nonetheless, useful technique. It is widely known that the yield of a genotype in different environments depends on environmental covariates, such as the amount of rainfall in some critical periods of time. Apart from rain, also temperature, wind, solar radiation, air humidity and soil ...
11662 sym R (9136 sym/9 pcs) 2 img