Calculating order parameter profiles utilizing magnetically aligned phospholipid bilayers for 2H solid-state NMR studies

Solid-state deuterium NMR spectroscopy was used to study the structural and dynamic properties of stearic acid-d(35) in magnetically aligned phospholipid bilayers as a function of temperature. Magnetically aligned phospholipid bilayers or bicelles are model systems, which mimic biological membranes for magnetic resonance studies. Paramagnetic lanthanide ions (Yb(3+)) were added to align the bicelles such that the bilayer normal is colinear with the direction of the static magnetic field. The corresponding order parameters of the stearic acid-d(35) probe were calculated and compared with values obtained from unoriented samples in the literature. The addition of cholesterol to the bicelle system decreases the fluidity of the phospholipid bilayers and increases the ordering of the acyl chains of stearic acid-d(35). This study demonstrates the feasibility of utilizing magnetically aligned bicelles for calculating 2H order parameter profiles for non-biological systems such as polymer-grafted membranes and Schiff's base complexes.     

Unnatural selection: talent identification and development in sport

The early identification of talented individuals has become increasingly important across many performance domains. Current talent identification (TI) schemes in sport typically select on the basis of discrete, unidimensional measures at unstable periods in the athlete's development. In this article, the concept of talent is revised as a complex, dynamical system in which future behaviors emerge from an interaction of key performance determinants such as psychological behaviors, motor abilities, and physical characteristics. Key nonlinear dynamics concepts are related to TI approaches such as sensitivity to initial conditions, transitions, and exponential behavioral distributions. It is concluded that many TI models place an overemphasis on early identification rather than the development of potentially talented performers. A generic model of talent identification and development is proposed that addresses these issues and provides direction for future research.     

On a Discrete-in-Time Order-Level Inventory Model for Deteriorating Items

An Order-Level inventory model continuous in units and discrete in time is developed for deteriorating items. The model is developed under deterministic demand and instantaneous delivery. Deterioration is assumed to be a constant fraction of the onhand inventory. An example is given to illustrate the model.