Evidence of malpractice

Investigate which, if any, of the following 4 papers present evidence of malpractice. We will need an objective approach to finding duplications, rotations, etc. and not one based simply on your visual perception, though of course your visual perception can help guide your research. We suggest using feature extraction and matching algorithms such as those found in OpenCV (SIFT, FLANN) to reach a forensically sound conclusion. You can start at https://opencv24-python- tutorials.readthedocs.io/en/latest/py_tutorials/py_feature2d/py_matcher/py_matcher.html for the algorithms and at https://pubpeer.com/ for examples of malpractice. It is advisable as well to follow Dr. Elisabeth Bik (Twitter handle @MicrobiomDigest) the leading expert in the field. The 4 papers to analyse are: 1 https://www.nature.com/articles/s41598-019-43093-x 2 https://www.nature.com/articles/s41598-019-41059-7 3 https://www.nature.com/articles/s41598-019-49821-7 4 https://www.nature.com/articles/s41598-019-49909-0