Classical Morphology of Plants as an Elementary Instance of Classical Invariant Theory

It has long been known that structural chemistry shows an intriguing correspondence with Classical Invariant Theory (CIT). Under this view, an algebraic binary form of the degree n corresponds to a chemical atom with valence n and each physical molecule or ion has an invariant-theoretic counterpart. This theory was developed using the Aronhold symbolical approach and the symbolical processes of convolution/transvection in CIT was characterized as a potential “accurate morphological method”. However, CIT has not been applied to the formal morphology of living organisms. Based on the morphological interpretation of binary form, as well as the process of convolution/transvection, the First and Second Fundamental Theorems of CIT and the Nullforms of CIT, we show how CIT can be applied to the structure of plants, especially when conceptualized as a series of plant metamers (phytomers). We also show that the weight of the covariant/invariant that describes a morphological structure is a criterion of simplicity and, therefore, we argue that this allows us to formulate a parsimonious method of formal morphology. We demonstrate that the “theory of axilar bud” is the simplest treatment of the grass seedling/embryo. Our interpretations also represent Troll's bauplan of the angiosperms, the principle of variable proportions, morphological misfits, the basic types of stem segmentation, and Goethe's principle of metamorphosis in terms of CIT. Binary forms of different degrees might describe any repeated module of plant organisms. As bacteria, invertebrates, and higher vertebrates are all generally shared a metameric morphology, wider implications of the proposed symmetry between CIT and formal morphology of plants are apparent

Univariate and multivariate models for the prediction of life-threatening complications in 586 cases of deep neck space infections: retrospective multi-institutional study

AbstractObjective:To identify deep neck infection factors related to life-threatening complications.Methods:This retrospective multi-institutional study comprised 586 patients treated for deep neck infections between 2002 and 2012. The statistical significance of variables associated with life-threatening complications of deep neck infections was assessed.Results:During treatment, life-threatening complications occurred in 60 out of 586 cases. On univariate analysis, life-threatening complications were linked to: dyspnoea, neck movement disturbance and dysphonia (all p &lt; 0.001); and parapharyngeal, anterior visceral or pretracheal deep neck involvement (all p &lt; 0.002). Aetiology was significantly linked to tonsils (p &lt; 0.001). Regarding infection type, fasciitis was a significant factor (p &lt; 0.001). Candida albicans was a significant bacterial culture (p &lt; 0.001). A multivariate step-wise model disclosed fewer significant variables: retropharyngeal space (p = 0.005) and major blood vessels area (p = 0.006) involvement, and bacterial culture C albicans (p &lt; 0.001).Conclusion:It can be predicted that patients with deep neck infections, with neck movement disturbances, dysphonia, dyspnoea and swelling of the external neck, accompanied by severe pain, and inflammatory changes in the retropharyngeal space and large vessel areas, with culture-confirmed infection of C albicans, are likely to develop life-threatening complications.</jats:sec