Alternative Pricing Methods for Shout Call Options

Shout call options are exotic options that give the investor the ability to \u27shout\u27 during the life of the option, thus locking in a profit and resetting the strike price to the prevailing spot price. We look at two approaches to value such options. The first approach makes use of canonical variables of the classical heat equation and results in a series solution. In the second approach an integral formulation is used, which can be more amenable to pricing when there is more than one \u27shout\u27 allowed

Educating Farmers\u27 Market Consumers on Best Practices for Retaining Maximum Nutrient and Phytonutrient Levels in Local Produce

Few farmers\u27 market consumers are aware of how to retain optimal nutritional quality of produce following purchase. Our objective was to develop and evaluate educational materials intended to inform market consumers about best practices for storing, preserving, and consuming local produce to maximize nutrients and phytonutrients. Printed educational materials were developed and then evaluated via a survey of and interviews with Ohio farmers\u27 market consumers. The materials were modified to reflect consumer comments, and finalized materials were distributed to farmers\u27 markets throughout Ohio. The approach we used can be applied by other Extension professionals when developing educational materials for different audiences

Multiplexed, High Density Electrophysiology with Nanofabricated Neural Probes

Extracellular electrode arrays can reveal the neuronal network correlates of behavior with single-cell, single-spike, and sub-millisecond resolution. However, implantable electrodes are inherently invasive, and efforts to scale up the number and density of recording sites must compromise on device size in order to connect the electrodes. Here, we report on silicon-based neural probes employing nanofabricated, high-density electrical leads. Furthermore, we address the challenge of reading out multichannel data with an application-specific integrated circuit (ASIC) performing signal amplification, band-pass filtering, and multiplexing functions. We demonstrate high spatial resolution extracellular measurements with a fully integrated, low noise 64-channel system weighing just 330 mg. The on-chip multiplexers make possible recordings with substantially fewer external wires than the number of input channels. By combining nanofabricated probes with ASICs we have implemented a system for performing large-scale, high-density electrophysiology in small, freely behaving animals that is both minimally invasive and highly scalable

Long-term modification of cortical synapses improves sensory perception

Synapses and receptive fields of the cerebral cortex are plastic. However, changes to specific inputs must be coordinated within neural networks to ensure that excitability and feature selectivity are appropriately configured for perception of the sensory environment. Long-lasting enhancements and decrements to rat primary auditory cortical excitatory synaptic strength were induced by pairing acoustic stimuli with activation of the nucleus basalis neuromodulatory system. Here we report that these synaptic modifications were approximately balanced across individual receptive fields, conserving mean excitation while reducing overall response variability. Decreased response variability should increase detection and recognition of near-threshold or previously imperceptible stimuli, as we found in behaving animals. Thus, modification of cortical inputs leads to wide-scale synaptic changes, which are related to improved sensory perception and enhanced behavioral performance

A theory of how active behavior stabilises neural activity: neural gain modulation by closed-loop environmental feedback

During active behaviours like running, swimming, whisking or sniffing, motor actions shape sensory input and sensory percepts guide future motor commands. Ongoing cycles of sensory and motor processing constitute a closed-loop feedback system which is central to motor control and, it has been argued, for perceptual processes. This closed-loop feedback is mediated by brainwide neural circuits but how the presence of feedback signals impacts on the dynamics and function of neurons is not well understood. Here we present a simple theory suggesting that closed-loop feedback between the brain/body/environment can modulate neural gain and, consequently, change endogenous neural fluctuations and responses to sensory input. We support this theory with modeling and data analysis in two vertebrate systems. First, in a model of rodent whisking we show that negative feedback mediated by whisking vibrissa can suppress coherent neural fluctuations and neural responses to sensory input in the barrel cortex. We argue this suppression provides an appealing account of a brain state transition (a marked change in global brain activity) coincident with the onset of whisking in rodents. Moreover, this mechanism suggests a novel signal detection mechanism that selectively accentuates active, rather than passive, whisker touch signals. This mechanism is consistent with a predictive coding strategy that is sensitive to the consequences of motor actions rather than the difference between the predicted and actual sensory input. We further support the theory by re-analysing previously published two-photon data recorded in zebrafish larvae performing closed-loop optomotor behaviour in a virtual swim simulator. We show, as predicted by this theory, that the degree to which each cell contributes in linking sensory and motor signals well explains how much its neural fluctuations are suppressed by closed-loop optomotor behaviour. More generally we argue that our results demonstrate the dependence of neural fluctuations, across the brain, on closed-loop brain/body/environment interactions strongly supporting the idea that brain function cannot be fully understood through open-loop approaches alone

Importance of the difference in surface pressures of the cell membrane in doxorubicin resistant cells that do not express Pgp and ABCG2

P-glycoprotein (Pgp) represents the archetypal mechanism of drug resistance. But Pgp alone cannot expel drugs. A small but growing body of works has demonstrated that the membrane biophysical properties are central to Pgp-mediated drug resistance. For example, a change in the membrane surface pressure is expected to support drug–Pgp interaction. An interesting aspect from these models is that under specific conditions, the membrane is predicted to take over Pgp concerning the mechanism of drug resistance especially when the surface pressure is high enough, at which point drugs remain physically blocked at the membrane level. However it remains to be determined experimentally whether the membrane itself could, on its own, affect drug entry into cells that have been selected by a low concentration of drug and that do not express transporters. We demonstrate here that in the case of the drug doxorubicin, alteration of the surface pressure of membrane leaflets drive drug resistance

Establishment and characterization of a bladder cancer cell line with enhanced doxorubicin resistance by mevalonate pathway activation

Resistance to chemotherapy is a major problem in the treatment of urothelial bladder cancer. Several mechanisms have been identified in resistance to doxorubicin by analysis of resistant urothelial carcinoma (UC) cell lines, prominently activation of drug efflux pumps and diminished apoptosis. We have derived a new doxorubicin-resistant cell line from BFTC-905 UC cells, designated BFTC-905DOXO-II. A doxorubicin-responsive green fluorescent protein (GFP) reporter assay indicated that resistance in BFTC905-DOXO-II was not due to increased drug efflux pump activity, whereas caspase-3/7 activation was indeed diminished. Gene expression microarray analysis revealed changes in proapoptotic and antiapoptotic genes, but additionally induction of the mevalonate (cholesterol) biosynthetic pathway. Treatmentwithsimvastatin restored sensitivity of BFTC-905DOXO-II to doxorubicin to that of the parental cell line. Induction of the mevalonate pathway has been reported as a mechanism of chemoresistance in other cancers; this is the first observation in bladder cancer. Combinations of statins with doxorubicin-containing chemotherapy regimens may provide a therapeutic advantage in such case