Taking heed of the 'danger space': acute descending necrotising mediastinitis secondary to primary odontogenic infection.

Descending necrotising mediastinitis (DNM) is an uncommon clinical entity which may arise secondary to primary odontogenic or neck infection in susceptible patients. Infection may spread contiguously via the alar or 'danger' space, a potential anatomical space posterior to the true retropharyngeal space.1 Spread of infection to the mediastinum almost always necessitates urgent cardiothoracic surgical intervention.2-4 This case report describes a male patient whose clinical deterioration following the diagnosis of submandibular abscess was investigated with CT imaging of the chest, where a diagnosis of DNM was made. Diagnosis was confirmed following surgical intervention and aspiration of pus from the mediastinum.

Individual Differences in Nonsymbolic Ratio Processing Predict Symbolic Math Performance.

What basic capacities lay the foundation for advanced numerical cognition? Are there basic nonsymbolic abilities that support the understanding of advanced numerical concepts, such as fractions? To date, most theories have posited that previously identified core numerical systems, such as the approximate number system (ANS), are ill-suited for learning fraction concepts. However, recent research in developmental psychology and neuroscience has revealed a ratio-processing system (RPS) that is sensitive to magnitudes of nonsymbolic ratios and may be ideally suited for supporting fraction concepts. We provide evidence for this hypothesis by showing that individual differences in RPS acuity predict performance on four measures of mathematical competence, including a university entrance exam in algebra. We suggest that the nonsymbolic RPS may support symbolic fraction understanding much as the ANS supports whole-number concepts. Thus, even abstract mathematical concepts, such as fractions, may be grounded not only in higher-order logic and language, but also in basic nonsymbolic processing abilities.