Game theory approach to optimal linear state estimation and itsrelation to the minimum H∞-normestimation

A possible game theory approach to optimal state estimation is presented. It is found that in a certain differential game, the minimizer's policy is identical to the one obtained by optimal estimation in the minimum H_∞-norm sense. This interpretation of H_∞-optimal state estimation provides better insight into the mechanism of H_∞ -optimal filtering, especially in the case where the exogenous signals are not energy bounded     

Timing Nitrogen Fertilizer Application to Reduce Nitrogen Losses to the Environment

The advantage of using insurance to help a farmeradopt a best nitrogen management plan (BNMP) thatreduces the impact of agricultural production on theenvironment is analytically and empiricallydemonstrated. Using an expected value analysis, it isshown that an insurance program can be structured soas to reduce a farmer's cost of bearing the adoptionrisk associated with changing production practicesand, thus, to improve the farmer's certaintyequivalent net return thereby promoting the adoptionof a BNMP. Using the adoption of growing-season onlyN fertilizer application in Iowa as a case study, itis illustrated how insurance may be used to promotethe adoption of this practice to reduce N fertilizeruse. It is shown that it is possible for a farmer andan insurance company both to have an incentive todevelop an insurance adoption program that willbenefit both the farmer and the insurance company,increasing net social welfare and improvingenvironmental quality in Iowa.     

Directional interpolation via all-pass transfer function matricesand its application in Hankel-norm approximations

A new approach to the problem of multivariable interpolation via all-pass transfer function matrices that are not necessarily stable is presented. The approach applies to both state-space and classical function theoretic arguments and obtains a very simple expression for the all-pass matrix that satisfies the interpolation requirement. Unlike the solution that is obtained by the generalized Nevanlinna-Pick algorithm, this expression is derived in closed form explicitly in terms of the interpolation parameters. It allows a detailed investigation of the structure of the all-pass solution, and it is readily used in Hankel-norm approximations of linear multivariable systems     

Long Residence Times Revealed by Aurora A Kinase‐Targeting Fluorescent Probes Derived from Inhibitors MLN8237 and VX‐689

We report the development of three fluorescent probes for protein kinase Aurora A that are derived from the well‐known inhibitors MLN8237 and VX‐689 (MK‐5108). Two of these probes target the ATP site of Aurora A, and one targets simultaneously the ATP and substrate sites of the kinase. The probes were tested in an assay with fluorescence polarisation/anisotropy readout, and we demonstrated slow association kinetics and long residence time of the probes (k_on 10⁵–10⁷ M ^?1 s^?1, k_off 10^?3–10^?4 s^?1; residence time 500–3000 s). The presence of the Aurora A activator TPX2 caused a significant reduction in the on‐rate and increase in the off‐rate of fluorescent probes targeting ATP site. These observations were supported by Aurora A inhibition assays with MLN8237 and VX‐689. Overall, our results emphasise the importance of rational design of experiments with these compounds and correct interpretation of the obtained data.     

Perpendicular Orientation of Anisotropic Au‐Tipped CdS Nanorods at the Air/Water Interface

Anisotropic CdS nanorods tipped by Au nanoparticles on one edge (Au‐CdS‐NRs) are perpendicularly oriented at the air/water interface, whereby all the Au tips are located in the subphase, using the Langmuir–Blodgett technique. Since these nano‐objects reveal light‐induced charge separation at the semiconductor/metal interface, it is of high interest to control their organization. The orientation of these assemblies is studied in situ while compressing the Langmuir–Blodgett trough using the π‐A isotherm, Brewster angle microscopy, and horizontal touch voltammetry. All these analyses clearly confirm the induced organization of the amphiphilic Au‐CdS‐NRs by compression of the Langmuir layer. The compressed layers are successfully transferred by the Langmuir–Schaefer method onto transmission electron microscopy grids while maintaining the preferential orientation as analyzed by transmission, scanning and scanning trasmission electron microscopy, and X‐ray photoelectron spectroscopy. As far as can be determined, the Langmuir–Blodgett technique has not been used so far for perpendicularly orienting anisotropic nano‐objects. Moreover, these findings clearly demonstrate that anisotropic amphiphilic nano‐objects can be treated with some similarity to the traditional amphiphilic molecular building blocks.     

Nanoscale assembly in biological systems: from neuronal cytoskeletal proteins to curvature stabilizing lipids

The review will describe experiments inspired by the rich variety of bundles and networks of interacting microtubules (MT), neurofilaments, and filamentous-actin in neurons where the nature of the interactions, structures, and structure-function correlations remain poorly understood. We describe how three-dimensional (3D) MT bundles and 2D MT bundles may assemble, in cell free systems in the presence of counter-ions, revealing structures not predicted by polyelectrolyte theories. Interestingly, experiments reveal that the neuronal protein tau, an abundant MT-associated-protein in axons, modulates the MT diameter providing insight for the control of geometric parameters in bio- nanotechnology. In another set of experiments we describe lipid-protein-nanotubes, and lipid nano-tubes and rods, resulting from membrane shape evolution processes involving protein templates and curvature stabilizing lipids. Similar membrane shape changes, occurring in cells for the purpose of specific functions, are induced by interactions between membranes and proteins. The biological materials systems described have applications in bio-nanotechnology.     

Synchronized External Pulsation for Improved Tolerance to Acceleration Stress: Model Studies and Preliminary Experiments

Synchronized external pulsation is proposed as a method to improve tolerance to acceleration stress. This technique uses a modified anti-G suit which is pressurized and depressurized synchronously with the heart cycle. The feasibility of the procedure has been studied using a computer model of the cardiovascular system which includes the effects of Gz stress, and contains simulations of baroreceptor control of heart rate and venous tone. Model predictions indicate that for unprotected subjects, carotid pressure at eye level (ophthalmic artery pressure) decreases to 20 mmHg (beginning of central light loss) at approximately +3.6 Gz. Applying standard anti-G suit pressure to the model increases this level to 5.3 Gz. When synchronized external pulsation of 2 psi is superimposed on the standard anti-G suit pressure, the tolerance to acceleration stress is further augmented by at least 0.9 G above the protection afforded by the standard anti-G suit alone. A set of preliminary experiments on human subjects to test the feasibility of using the technique in the high-G environment has also been carried out. The results under various protection modes compare favorably to the model predictions. Our results suggest that the computer model presented here is a useful tool for studying cardiovascular responses under +GZ stress. It also indicates that using synchronized external pulsation pressure superimposed on the standard anti-G suit pressure may offer extra protection to acceleration stress.     

Two-degree-of-freedom H∞-optimization ofmultivariable feedback systems

A solution to the two-degree-of-freedom H_∞ -minimization problem that arises in the design of multivariable optimal continuous-time stochastic control systems is derived. A decoupling approach that enables a partially independent design of the prefilter and the feedback controller and yields a simple solution to the optimization problem is applied. This solution is obtained by transforming the optimization problem into two standard form (four-block) problems