A segmentation approach to long duration surface EMG recordings.

The purpose of this study was to develop an automatic segmentation method in order to identify postural surface EMG segments in long-duration recordings. Surface EMG signals were collected from the cervical erector spinae (CES), erector spinae (ES), external oblique (EO), and tibialis anterior (TA) muscles of 11 subjects using a bipolar electrode configuration. Subjects remained seated in a car seat over the 150-min data-collection period. The modified dynamic cumulative sum (MDCS) algorithm was used to automatically segment the surface EMG signals. Signals were rejected by comparison with an exponential mathematical model of the spectrum of a surface EMG signal. The average power ratio computed between two successive retained segments was used to classify segments as postural or surface EMG. The presence of a negative slope of a regression line fitted to the median frequency values of postural surface EMG segments was taken as an indication of fatigue. Alpha level was set at 0.05. The overall classification error rate was 8%, and could be performed in 25 min for a 150-min signal using a custom-built software program written in C (Borland Software Corporation, CA, USA). This error rate could be enhanced by concentrating on the rejection method, which caused most of the misclassification (6%). Furthermore, the elimination of non-postural surface EMG segments by the use of a segmentation approach enabled muscular fatigue to be identified in signals that contained no evidence of fatigue when analysed using traditional methods.     

Distribution,bioclimatic niche and sympatry of two Erinaceidae in Tunisia

Numerous mammalian species of North Africa have an enigmatic distribution between the Mediterranean and Saharan area. In order to study the distribution of hedgehogs in Tunisia, field data were collected from several protected areas and various natural and peri-urban environments during 4 years 2015–2018 covering the all bioclimatic zones present in the country. The present work provides a detailed geographical and ecological distribution of hedgehogs with a total of 168 occurrence data of Atelerix algirus and Paraechinus aethiopicus. Atelerix algirus showed a wide distribution range from north to south being absent only in the extreme Saharan environment. Paraechinus aethiopicus has been recorded in the centre and the south with a specialisation in the arid and Saharan environment. A parapatry distribution is also shown with a sympatric area between arid and Saharan bioclimates. Our results improve knowledge of the bioclimatic niche and habitat characteristic of these taxa not clearly defined in previous research. The presence of the two hedgehogs on Djerba Island (A. algirus and P. aethiopicus) is also confirmed.     

Temporal patterns in natality and mortality of three threatened antelope species in North Africa: Oryx dammah,Addax nasomaculatus and Nanger dama

Long‐term population studies on large mammals are rare. Here, we have examined the threatened scimitar‐horned oryx, addax and dama gazelle's populations over the last 20 years in Bou Hedma National Park. Using monthly count data of the three studied species collected since 1995, we examined their population trends. Using autocorrelation analyses, we discovered endogenous natural cyclical fluctuations in the numbers of each species, with a periodicity of approximately 3 years. For all three studied species which seem to be opportunistic breeders, births and deaths occurred throughout the year, although with notable seasonality. By means of cross‐correlation, we discovered that during the first 7 years for which data were available, addax numbers were positively correlated with those of dama and inversely correlated with numbers of oryx. This pattern reversed during the following 4‐year period. The number of oryx was negatively correlated with dama during the first 4 years and then became positively correlated during the subsequent 7‐year period. Thus, we draw attention to difference in response to environmental and anthropogenic factors. Incorporating fundamental long‐term population data into developing management approaches, especially for potentially competitive species, is vital for their future long‐term survival and the success of conservation actions.