Design, fabrication and test of a flueric servovalve

Design and performance of pneumatic-input fluidic servovalv

Design, fabrication and test of a flueric servovalve Quarterly report, 28 Sep. - 28 Dec. 1965

Breadboard model of pneumatic-input flueric servovalve test

Development in a biologically inspired spinal neural network for movement control

In two phases, we develop neural network models of spinal circuitry which self-organises into networks with opponent channels for the control of an antagonistic muscle pair. The self-organisation is enabled by spontaneous activity present in the spinal cord. We show that after the process of self-organisation, the networks have developed the possibility to independently control the length and tension of the innerated muscles. This allows the specification of joint angle independent from the specification of joint stiffness. The first network comprises only motorneurons and inhibitory interneurons through which the two channels interact. The inhibitory interneurons prevent saturation of the motorneuron pools, which is a necessary condition for independent control. In the second network, however, the neurons in the motorneuron pools obey the size-principle, which is a threat to the desired invariance of joint angle for varying joint stiffness, because of the different amplification of inputs in the case these inputs are not equal. To restore the desired invariance the second network ha.s been expanded with Renshaw cells. The manner in which they are included in the circuitry corrects the problem caused by the addition of the size-principle. The results obtained from the two models compare favourably with the FLETE-model for spinal circuitry (Bullock & Grossberg, 1991; Bullock et al., HJ93; Bullock & Contreras-Vidal, 1993) which has been successful in explaining several phenomena related to motor control.Fulbright Scholarship; Office of Naval Research (N00014-92-J-1309, N00014-95-1-0409

We Need Faithful Farmers

A faithful farmer who cares is performing worshipful work. Posting about the calling of agriculture from In All Things - an online journal for critical reflection on faith, culture, art, and every ordinary-yet-graced square inch of God’s creation. https://inallthings.org/we-need-faithful-farmers

Biomarkers of focal and diffuse traumatic brain injury

Traumatic brain injury (TBI) is a pathologically heterogeneous disease affecting people of all ages. The highest incidence of TBI occurs in young people and the average age is 30 to 40 years. Injury grading may range from mild with a low frequency (1 per 100) of life-threatening intracranial hematoma that needs immediate neurosurgical operation and very low mortality (1 per 1,000) to severe with a high likelihood of life-threatening intracranial hematoma (up to 1 per 3), a 40% case fatality rate and a high disability rate (2 per 3) in survivors. Estimation of the prognosis in severe TBI is currently based on demographic and clinical predictors, including age, Glasgow Coma Scale, pupillary reactions, extracranial injury (hypotension and hypoxia) and computed tomography indices (brain swelling, focal mass lesions, subarachnoid hemorrhage). Biomarkers reflecting damage to neurons and astrocytes may add important complementary information to clinical predictors of outcome and provide insight into the pathophysiology of TBI

Limits on Lorentz violation in neutral-Kaon decay

The KLOE collaboration recently reported bounds on the directional dependence of the lifetime of the short-lived neutral kaon K_S with respect to the cosmic microwave background dipole anisotropy. We interpret their results in a general framework developed to probe Lorentz violation in the weak interaction. In this approach a Lorentz-violating tensor \chi_{\mu\nu} is added to the standard propagator of the W boson. We derive the K_S decay rate in a naive tree-level model and calculate the asymmetry for the lifetime. By using the KLOE data the real vector part of \chi_{\mu\nu} is found to be smaller than 10^-2. We briefly discuss the theoretical challenges concerning nonleptonic decays.Comment: Presented at the Sixth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 17-21, 2013

Intergenerational Risk Sharing, Pensions and Endogenous Labor Supply in General Equilibrium

In the context of a two-tier pension system, with a pay-as-you-go first tier and a fully funded second tier, we demonstrate that a system with a defined wage-indexed second tier performs strictly better than one with a defined contribution or defined real benefit second tier. The former completely separates systematic redistribution (confined to the first tier) from intergenerational risk sharing (the role of the second tier). This way labor supply is undistorted.funded pensions, risk sharing, overlapping generations, endogenous labour supply

Equilibrium of a Brownian particle with coordinate dependent diffusivity and damping: Generalized Boltzmann distribution

Fick's law for coordinate dependent diffusivity is derived. Corresponding diffusion current in the presence of coordinate dependent diffusivity is consistent with the form as given by Kramers-Moyal expansion. We have obtained the equilibrium solution of the corresponding Smoluchowski equation. The equilibrium distribution is a generalization of the Boltzmann distribution. This generalized Boltzmann distribution involves an effective potential which is a function of coordinate dependent diffusivity. We discuss various implications of the existence of this generalized Boltzmann distribution for equilibrium of systems with coordinate dependent diffusivity and damping.Comment: 11 pages, 1 figur