Formal studies of decision threshold learning assume full feedback conditions, that is, no matter what the decision is (positive or negative), the feedback will be provided. However, in the real world feedback may be conditional on the decision made. For example, in college admissions decisions, there is no feedback available for the students who are not admitted. In this paper, we investigate ...

Controlled mechanical ventilation is characterized by a fixed breathing frequency and tidal volume. Physiological and mathematical models have demonstrated the beneficial effects of varying tidal volume and/or inspiratory pressure during positive-pressure ventilation. The addition of noise (random changes) to a monotonous nonlinear biological system, such as the lung, induces stochastic resonan...

We applied a physical model of the human vocal tract, which was originally designed for simulating English /r/, and tested whether the model can produce a certain range of vowels, especially mid front vowels. We first confirmed that the model can produce such vowels with high intelligibility. By changing the tongue height of the model, learners can adjust the vowel quality by listening to the o...

M observation of others’ choices can be informative about product quality. This paper develops an individual-level dynamic model of observational learning and applies it to a novel data set from the U.S. kidney market, where transplant candidates on a waiting list sequentially decide whether to accept a kidney offer. We find strong evidence of observational learning: patients draw negative qual...

A general theory of innovation and progress in human society is outlined, based on the combat between two opposite forces (conservatism/inertia and speculative herding “bubble” behavior). We contend that human affairs are characterized by ubiquitous “bubbles”, which involve huge risks which would not otherwise be taken using standard cost/benefit analysis. Bubbles result from self-reinforcing p...

Plant-soil feedbacks have been implicated in several successful plant invasions. However, simple identification of a feedback alone may not be enough to establish feedbacks as a mechanism behind plant invasion. I suggest that the relationship between soil community density and plant growth is an important unknown that strongly influences the impact of plant-soil feedbacks. I developed a mathema...

We propose a stochastic dynamic model of migration and economic aggregation in a system of employed (immobile) and unemployed (mobile) agents which respond to local wage gradients. Dependent on the local economic situation, described by a production function which includes cooperative effects, employed agents can become unemployed and vice versa. The spatiotemporal distribution of employed and ...

Overview of Normal Sexual Development The purpose of this review is to briefly describe inherited disorders resulting in ambiguous sexual morphology that have been reported in the dog and cat. An understanding of normal development is helpful in formulating a diagnostic plan and reaching a definitive diagnosis. Normal mammalian sexual development occurs in three steps, with each step depending ...

Bigger governments raise the possibilities for corruption; more corruption may in turn raise the support for redistributive policies that intend to correct the inequality and injustice generated by corruption. We formalize these insights in a simple dynamic model. A positive feedback from past to current levels of taxation and corruption arises either when wealth originating in corruption and r...

Cooperation and diversity abound in nature despite cooperators risking exploitation from defectors and superior competitors displacing weaker ones. Understanding the persistence of cooperation and diversity is therefore a major problem for evolutionary ecology, especially in the context of well-mixed populations, where the potential for exploitation and displacement is greatest. Here, we demons...