Morphological Variations of Sacrum in Adult Indian Population

Introduction: The sacrum is considered as a highly variable bone. Several morphological variations have been documented which exhibit differences in the frequency of occurrence and morphological characteristics in various study populations. Variant anatomy of the sacrum may be associated with backache, enuresis, neurological anomalies of the lower limb and functional disorders of lower urinary tract. Purpose: The purpose of this study was to identify and describe morphological variations of sacrum in Indian population and enable comparison with different populations. Materials and Methods: The study was conducted on 108 dry adult human sacra and morphological characteristics and variations were noted. Results: Sacral skewness was observed in 7.4% sacra with right sided skewness being predominant. The presence of accessory auricular surface (AAS) was noted in 13% sacra which was at the level of S3 vertebra in most sacra. Spina bifida (SB) was observed in 11.1% sacra and it was most commonly located at S1 vertebral level. Furthermore, the lumbo-sacral transitional vertebra (TV) was documented in 10.2% sacra. Conclusions: Sacrum displays numerous variations in Indian population such as skewness, AAS, SB and TV. Thorough knowledge of morphological characteristics and variations of sacrum is vital and should be contemplated during diagnosis and treatment of sacrum-related diseases.

Automatic detection and classification of atrial fibrillation using RR intervals and multi-eigenvalue / 生物医学工程学杂志

Atrial fibrillation (AF) is a common arrhythmia disease. Detection of atrial fibrillation based on electrocardiogram (ECG) is of great significance for clinical diagnosis. Due to the non-linearity and complexity of ECG signals, the procedure to manually diagnose the ECG signals takes a lot of time and is prone to errors. In order to overcome the above problems, a feature extraction method based on RR interval is proposed in this paper. The discrete degree of RR interval is described with the robust coefficient of variation (RCV), the distribution shape of RR interval is described with the skewness parameter (SKP), and the complexity of RR interval is described with the Lempel-Ziv complexity (LZC). Finally, the feature vectors of RCV, SKP, and LZC are input into the support vector machine (SVM) classifier model to achieve automatic classification and detection of atrial fibrillation. To verify the validity and practicability of the proposed method, the MIT-BIH atrial fibrillation database was used to verify the data. The final classification results show that the sensitivity is 95.81%, the specificity is 96.48%, the accuracy is 96.09%, and the specificity of 95.16% is achieved in the MIT-BIH normal sinus rhythm database. The experimental results show that the proposed method is an effective classification method for atrial fibrillation.

Stylish lengths: Mate choice in flowers.

The styles of flowers may represent an arena for pollen competition in the race to fertilize ovules. Accordingly, selection should favour a longer ‘race’ to better discriminate among variable pollen by increasing style length. Sampling across a taxonomically diverse range of wild and outcrossed species, we found that the distribution of style lengths within plants were skewed towards longer styles, as predicted. In self-pollinated domesticated species, where discrimination among pollen is less important, we found no such pattern. We conclude that style length is under directional selection towards longer styles as a mechanism for mate choice among pollen of variable quality.

Macroevolutionary dynamics and comparative methods of morphological diversification

Among the comparative approaches that have been used to understand the patterns of morphologicaldiversification, those related to the detection and evaluation of large-scale evolutionary trends have recentlybeen highlighted. A new method known as the analysis of skewness (ANSKEW) allows partitioning betweenthe passive and driven trends associated with the random occupation of a bounded morphological spaceand a single morphological attractor, respectively. This partitioning provides a better understanding of therelative role of processes that occur at distinct hierarchical levels associated with the macroevolutionarytrends of morphological diversification. In this paper, we used this new approach to understand the patternsof morphological diversification in Erodiscini (Coleoptera, Curculionidae, Otidocephalinae) beetles. Whengenera were used as subclades, ANSKEW revealed that 19.9% of the body size variation in the Erodiscini wasattributable to driven trends, i.e., a morphological attractor, whereas 80.1% of the variation was attributableto the occupation of different adaptive zones by distinct subclades (a passive process), with the passivecomponents being significant (based on 5,000 bootstrap samples). This simple approach to partitioningprovided insights into the intrinsic dynamics of body size evolution in this group without the need to considerexplicit phylogenetic structures. Such analyses could provide a starting point for further evaluation of adaptivevariation at multiple hierarchical levels and of the processes underlying the relationship between variationin body size and other ecological, physiological and behavioral aspects.