Stochastic Cost Benefit Rules: A Back-of-a-Lottery-Ticket Calculation Method

In this paper, we introduce cost benefit rules for projects embedded in a stochastic optimal growth framework. We model uncertainty in terms of Brownian motion and Ito integrals. Taking the mathematical expectation of the project means that the Ito integrals vanish, and we end up with a cost benefit rule that closely resembles its deterministic counterpart.Cost benefit analysis; stochastic optimal control theory; Brownian motion

Expression and role of the universal stress protein, UspA, of Escherichia coli during growth arrest

The synthesis of the small, cytoplasmic protein UspA universal stress protein A) of Escherichia coli is induced as soon as the cell growth rate falls below the maximal growth rate supported by the medium, regardless of the condition inhibiting growth. The increase in UspA synthesis appears to be the result of Induction of the monocistronic uspA gene. Induction of this gene during a heat-shock treatment is demonstrated to be the result of transcriptional activation of Σ 70 -dependent promoter which has previously been shown to be activated also during carbon starvation-induced growth arrest. Mutant cells lacking UspA grow at rates indistinguisible from the isogenic parent at different temperatures and in the presence of different growth inhibitors but are impaired in their ability to survive prolonged periods of complete growth inhibition caused by a variety of diverse stresses, including CdCl 2 , H 2 O 2 , DNP, CCCP exposure, and osmotic shock. Moreover, the uspA mutation results in an increased sensitivity of cells to carbon-source starvation (i.e. glucose, glycerol or succinate depletion). Also, the mutation causes a marked alteration in the timing of starvation protein expression but protein expression during steady-state growth appears to be normal. The results presented have prompted us to postulate that UspA may have a general protective function related to the growth arrest state.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73757/1/j.1365-2958.1994.tb00334.x.pd

Role of the \u3ci\u3eEscherichia coli\u3c/i\u3e FadR Regulator in Stasis Survival and Growth Phase-Dependent Expression of the \u3ci\u3euspA, fad\u3c/i\u3e, and \u3ci\u3efab\u3c/i\u3e Genes

The increased expression of the uspA gene of Escherichia coli is an essential part of the cell’s response to growth arrest. We demonstrate that stationary-phase activation of the uspA promoter is in part dependent on growth phase-dependent inactivation or repression of the FadR regulator. Transcription of uspA is derepressed during exponential growth in fadR null mutants or by including the fatty acid oleate in the growth medium of FadR1 cells. The results of DNA footprinting analysis show that FadR binds downstream of the uspA promoter in the noncoding region. Thus, uspA is a member of the fadR regulon. All the fad-lacZ fusions examined (fadBA, fadL, and fadD) are increasingly expressed in stationary phase with kinetics similar to that of the increased expression of uspA. In contrast, b-galactosidase levels decrease during stationary phase in a fabA-lacZ lysogen, consistent with the role of FadR as an activator of fabA. The growth phase-dependent increased and decreased transcription of fad genes and fabA, respectively, is dependent on the status of the fadR gene. Cells carrying a mutation in the FadR gene (fadRS219N) that makes it nonderepressible exhibit a weak stationary-phase induction of uspA and fad genes. In addition, cells carrying fadRS219N survive long-term stasis poorly, indicating that FadR-dependent alterations in fatty acid metabolism are an integral and important part of the adaptation to stationary phase

Role of the \u3ci\u3eEscherichia coli\u3c/i\u3e FadR Regulator in Stasis Survival and Growth Phase-Dependent Expression of the \u3ci\u3euspA, fad\u3c/i\u3e, and \u3ci\u3efab\u3c/i\u3e Genes

The increased expression of the uspA gene of Escherichia coli is an essential part of the cell’s response to growth arrest. We demonstrate that stationary-phase activation of the uspA promoter is in part dependent on growth phase-dependent inactivation or repression of the FadR regulator. Transcription of uspA is derepressed during exponential growth in fadR null mutants or by including the fatty acid oleate in the growth medium of FadR1 cells. The results of DNA footprinting analysis show that FadR binds downstream of the uspA promoter in the noncoding region. Thus, uspA is a member of the fadR regulon. All the fad-lacZ fusions examined (fadBA, fadL, and fadD) are increasingly expressed in stationary phase with kinetics similar to that of the increased expression of uspA. In contrast, b-galactosidase levels decrease during stationary phase in a fabA-lacZ lysogen, consistent with the role of FadR as an activator of fabA. The growth phase-dependent increased and decreased transcription of fad genes and fabA, respectively, is dependent on the status of the fadR gene. Cells carrying a mutation in the FadR gene (fadRS219N) that makes it nonderepressible exhibit a weak stationary-phase induction of uspA and fad genes. In addition, cells carrying fadRS219N survive long-term stasis poorly, indicating that FadR-dependent alterations in fatty acid metabolism are an integral and important part of the adaptation to stationary phase

Generating speech user interfaces from interaction acts

ABSTRACT We have applied interaction acts, an abstract user-service interaction specification, to speech user interfaces to investigate how well it lends itself to a new type of user interface. We used interaction acts to generate a VoiceXML-based speech user interface, and identified two main issues connected to the differences between graphical user interfaces and speech user interfaces. The first issue concerns the structure of the user interface. Generating speech user interfaces and GUIs from the same underlying structure easily results in a too hierarchical and difficult to use speech user interface. The second issue is user input. Interpreting spoken user input is fundamentally different from user input in GUIs. We have shown that it is possible to generate speech user interfaces based on. A small user study supports the results. We discuss these issues and some possible solutions, and some results from preliminary user studies

Conveying clinical reasoning based on visual observation via eye-movement modelling examples

Jarodzka, H., Balslev, T., Holmqvist, K., Nyström, M., Scheiter, K., Gerjets, P., & Eika, B. (2012). Conveying clinical reasoning based on visual observation via eye-movement modelling examples. Instructional Science, 40(5), 813-827. doi:10.1007/s11251-012-9218-5Complex perceptual tasks, like clinical reasoning based on visual observations of patients, require not only conceptual knowledge about diagnostic classes but also the skills to visually search for symptoms and interpret these observations. However, medical education so far has focused very little on how visual observation skills can be efficiently conveyed to novices. The current study applied a novel instructional method to teach these skills by showing the learners how an expert model visually searches and interprets symptoms (i.e., eye-movement modelling examples; EMMEs). Case videos of patients were verbally explained by a model (control condition) and presented to students. In the experimental conditions, the participants received a recording of the model’s eye movements superimposed on the case videos. The eye movements were displayed by either highlighting the features the model focused on with a circle (the circle condition) or by blurring the features the model did not focus on (the spotlight condition). Compared to the other two conditions, results show that a spotlight on the case videos better guides the students’ attention towards the relevant features. Moreover, when testing the students’ clinical reasoning skills with videos of new patient cases without any guidance participants studying EMMEs with a spotlight showed improved their visual search and enhanced interpretation performance of the symptoms in contrast to participants in either the circle or the control condition. These findings show that a spotlight EMME can successfully convey clinical reasoning based on visual observations

Actors that Unify Threads and Events

There is an impedance mismatch between message-passing concurrency and virtual machines, such as the JVM. VMs usually map their threads to heavyweight OS processes. Without a lightweight process abstraction, users are often forced to write parts of concurrent applications in an event-driven style which obscures control flow, and increases the burden on the programmer. In this paper we show how thread-based and event-based programming can be unified under a single actor abstraction. Using advanced abstraction mechanisms of the Scala programming language, we implemented our approach on unmodified JVMs. Our programming model integrates well with the threading model of the underlying VM

Learning perceptual aspects of diagnosis in medicine via eye movement modeling examples on patient video cases

Jarodzka, H., Balslev, T., Holmqvist, K., Nyström, M., Scheiter, K., Gerjets, P., & Eika, B. (2010). Learning perceptual aspects of diagnosis in medicine via eye movement modeling examples on patient video cases. In S. Ohlsson & R. Catrambone (Eds.), Proceedings of the 32nd Annual Conference of the Cognitive Science Society (pp. 1703-1708). Austin, TX: Cognitive Science Society.Complex tasks with a visually rich component, like diagnosing seizures based on patient video cases, not only require the acquisition of conceptual but also of perceptual skills. Medical education has found that besides biomedical knowledge (knowledge of scientific facts) clinical knowledge (actual experience with patients) is crucial. One important aspect of clinical knowledge that medical education has hardly focused on, yet, are perceptual skills, like visually searching, detecting, and interpreting relevant features. Research on instructional design has shown that in a visually rich, but simple classification task perceptual skills could be conveyed by means of showing the eye movements of a didactically behaving expert. The current study applied this method to medical education in a complex task. This was done by example video cases, which were verbally explained by an expert. In addition the experimental groups saw a display of the expert’s eye movements recorded, while he performed the task. Results show that blurring non-attended areas of the expert enhances diagnostic performance of epileptic seizures by medical students in contrast to displaying attended areas as a circle and to a control group without attention guidance. These findings show that attention guidance fosters learning of perceptual aspects of clinical knowledge, if implemented in a spotlight manner