Think it Over

This section of Resonance presents thought-provoking questions, and discusses answers a few months later. Readers are invited to send new questions, solutions to old ones and comments, to ‘Think It Over’, Resonance, Indian Academy of Sciences, Bangalore 560 080. Items illustrating ideas and concepts will generally be chosen.     

How do wings generate lift?

How lift is generated by a moving wing is understood satisfactorily. But the rigorous explanation requires elaborate theoretical background, and hence there are many simpler explanations in the popular literature. In the first part of this article, some such popular models are discussed after briefly dealing with some required preliminary ideas. The concluding part of the article will deal with some simple quantitative models and then tie up many of these simple ideas and propositions together to the rigorous momentum conservation principle placing these popular models in perspective.     

A Random Variable Related to the Inversion Vector of a Partial Random Permutation

In this article, we define the inversion vector of a permutation of the integers 1, 2, . . . , n. We set up a particular kind of permutation, called a partial random permutation. The sum of the elements of the inversion vector of such a permutation is a random variable of interest.     

Intransitive Dice

In a recent issue of Teaching Statistics, an intransitive dice competition was published. In this article some further interesting results about such dice are presented.     

Hierarchical self-assembly of actin in micro-confinements using microfluidics

We present a straightforward microfluidics system to achieve step-by-step reaction sequences in a diffusion-controlled manner in quasi two-dimensional micro-confinements. We demonstrate the hierarchical self-organization of actin (actin monomers—entangled networks of filaments—networks of bundles) in a reversible fashion by tuning the Mg²⁺ ion concentration in the system. We show that actin can form networks of bundles in the presence of Mg²⁺ without any cross-linking proteins. The properties of these networks are influenced by the confinement geometry. In square microchambers we predominantly find rectangular networks, whereas triangular meshes are predominantly found in circular chambers.     

Incorporating the views of obstetric clinicians in implementing evidence-supported labour and delivery suite ward rounds: a case study

Objectives: To implement evidence‐supported delivery suite ward rounds using strategies to overcome barriers. Design: Qualitative case study to identify barriers and a quantitative assessment of outcomes on ward rounds. Method: After an introduction to the proposed evidence‐supported delivery suite ward round reactions were elicited from 15 clinicians. Responses were categorized into barriers related to knowledge, skills, attitudes and behaviour. Using strategies to overcome these barriers, a weekly evidence‐supported ward round was established. During patient‐centred discussions, clinical questions were formulated. Following literature searches, evidence was acquired and appraised. Results: Clinicians had limited awareness about the potential benefits of a clinical librarian's support during ward rounds. They were unsure of their skills in evidence‐based practice. There was scepticism, fear of loss of autonomy, poor motivation and resistance to change. Clinicians identified several factors that could impinge on their practice. Using appropriate strategies when evidence‐supported ward rounds were conducted, 67 questions were raised. However only seven articles were appraised in time to affect decisions on that ward round. Conclusions: Knowledge of barriers was helpful in developing plans for implementation of evidence‐supported ward rounds. The pilot study indicates the feasibility of this approach.