Bipedal locomotion in Octopus vulgaris: A complementary observation and some preliminary considerations

Lacking an external shell and a rigid endoskeleton, octopuses exhibit a remarkable flexibility in their movements. Bipedal locomotion is perhaps the most iconic example in this regard. Until recently, this peculiar mode of locomotion had been observed only in two species of tropical octopuses: Amphioctopus marginatus and Abdopus aculeatus. Yet, recent evidence indicates that bipedal walking is also part of the behavioral repertoire of the common octopus, Octopus vulgaris. Here we report a further observation of a defense behavior that encompasses both postural and locomotory elements of bipedal locomotion in this cephalopod. By highlighting differences and similarities with the other recently published report, we provide preliminary considerations with regard to bipedal locomotion in the common octopus.     

A clinical comparison between two acoustic analysis softwares: MDVP and Praat

The Multi-Dimensional Voice Program (MDVP) and Praat are computer programs commonly used for acoustic analysis of voice in clinical and research settings. Both softwares extract a set of acoustic parameters, many of which are defined similarly. The purpose of this study was to compare results obtained by both programs, and examine whether they can clinically distinguish among pathological groups differently. Fifty-eight women participated in the study. Of these women, 28 were diagnosed with functional dysphonia and 30 were diagnosed with benign mass-lesions (10 nodules, ten polyps and 10 cysts). Six productions of the vowels /a/ and /i/, were analyzed using MDVP and Praat. Results show similar mean fundamental-frequency (mF0) values for both programs (P > 0.05). However, values of jitter, shimmer, noise-to-harmonic ratio (NHR) and degree of unvoiced (DUV) segment were significantly lower using Praat, in comparison with MDVP. Jitter values obtained using MDVP, for the vowel /i/, revealed a significant group difference between the nodule and cyst groups (P < 0.05). This group contrast was not observed using Praat. Results demonstrate that although high correlations are found between values obtained by both programs, individual numerical values vary greatly. Therefore, combining results from both programs are not advisable. In addition, there are indications that linear transformation for the results from one program to the other might lead to erroneous conclusions, and should be carried out with caution.