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In this paper, the response of two-dimensional framed structures made of rectangular cells to the sudden removal of columns is studied. A simulation algorithm based on the discrete-element method is employed, where the structural elements are represented by elasto-plastic Euler-Bernoulli beams with elongation-rotation failure threshold. The effect of structural cell slenderness and of topological hierarchy on the dynamic residual strength after damage is investigated. Topologically hierarchical frames have a primary structure made of a few massive elements, while homogeneous frames are made of many thin elements. It is also shown how depends on the activated collapse mechanisms, which are determined by the mechanical hierarchy between beams and columns, i.e., by their relative strength and stiffness. Finally, principles of robustness-oriented capacity design that seem to be in contrast to the conventional antiseismic capacity design are addressed. [ABSTRACT FROM AUTHOR]

In this paper, we study the progressive collapse of three-dimensional framed structures made of reinforced concrete after the sudden loss of a column. The structures are represented by elastoplastic Euler-Bernoulli beams with elongation-rotation failure threshold. We performed simulations using the discrete element method considering inelastic collisions between the structural elements. The results show what collapse initiation and impact-driven propagation mechanisms are activated in structures with different geometric and mechanical features. Namely, we investigate the influence of the cross sectional size and reinforcement α and of the plastic capacity β of the structural elements. We also study the final collapse extent and the fragment size distribution and their relation to α, β, and to the observed collapse mechanisms. Finally, we compare the damage response of structures with symmetric and asymmetric reinforcement in the beams. [ABSTRACT FROM AUTHOR]

Depression is the most prevalent functional psychiatric disorder in late life. The problem of motor disorders associated with antidepressant use is relevant in the elderly. Elderly people are physically more frail and more likely to be suffering from physical illness, and any drug given may exacerbate pre-existing diseases, or interact with other drug treatments being administered for physical conditions. Antidepressants have been reported to induce extrapyramidal symptoms, including parkinsonism. These observations prompted us to review the neurobiological mechanism that may be involved in this complex interplay including neurotransmitters and neuronal circuits involved in movement and emotion control and their changes related to aging and disease. The study of the correlations between motor and mood disorders and their putative biochemical bases, as presented in this review, provide a rationale either to understand or to foresee motor side effects for psychotropic drugs, in particular antidepressants. [ABSTRACT FROM AUTHOR]