Search results for "response"
showing 10 items of 4136 documents
Linear and nonlinear approximations for periodically driven bistable systems
2005
We analyze periodically driven bistable systems by two different approaches. The first approach is a linearization of the stochastic Langevin equation of our system by the response on small external force. The second one is based on the Gaussian approximation of the kinetic equations for the cumulants. We obtain with the first approach the signal power amplification and output signal-to-noise ratio for a model piece-wise linear bistable potential and compare with the results of linear response approximation. By using the second approach to a bistable quartic potential, we obtain the set of nonlinear differential equations for the first and the second cumulants.
Modeling sequential production: the migratory beekeeper case
2018
This paper formalizes a bio-economic model of migratory beekeeping activities, during the annual production cycle, so as to discern the optimal sequence of foraging sites for migratory beekeepers; it then proceeds to empirically verify the model via a case study. The model assumes that the apiary farm produces three marketable outputs under conditions of certainty with disjunctive resources at the sites. In particular, honey, commercial pollination services and nucleus colonies are produced sequentially at foraging sites throughout the year. The model determines a migratory beekeeperâs revenues, variable costs, gross income from each sequence of foraging sites under the constraint that th…
Metabolism and Lysine Biosynthesis Control in Brevibacterium Flavum: Impact of Stringent Response in Bacterial Cells
2005
Parameters affecting lysine biosynthesis by Brevibacterium flavum RC 115 cells under stringent response conditions (test guanosine 5′-diphosphate 3′-diphosphate accumulation in cells) caused by threonine limitation were investigated. Experimental results confirmed that an increase in lysine biosynthesis by this bacterium under stringent response conditions might be a result of an increase in the intracellular concentration of NADPH as well as lysine export activity.
Purification of recovered phosphoric acid by extracting aluminium with di-2-ethylhexyl phosphoric acid
2021
AbstractThe extraction of aluminium from dilute phosphoric acid with di-2-ethylhexyl phosphoric acid (DEHPA) was optimized using response surface methodology. The optimization was based on the experimental three-level central composite face-centred design (CCF) and was conducted on real-life samples. The three variables included were pH, extractant concentration and aqueous to organic phase ratio (AO). Under the optimized conditions (pH 2.5, 0.6 M DEHPA and AO ratio 1:2), extraction efficiency of 99% for aluminium in four extraction stages is achieved. The purified phosphoric acid solution can then be utilized by the fertilizing industry. Stripping tests for organic phase loaded with alumin…
Interferon-alpha (IFN-alpha) inhibits granulocyte-macrophage colony-stimulating factor (GM-CSF) expression at the post-transcriptional level in murin…
1995
Recently it has been shown that IFN-alpha inhibits expression of GM-CSF in adherent cells of human long-term bone marrow cultures (LTBMC) stimulated with interleukin-1 (IL-1), tumour necrosis factor-alpha (TNF-alpha) or endotoxin. The murine bone marrow stromal cell line +/+(-1).LDA11 was used to further define regulatory mechanisms of IFN-alpha inhibition on GM-CSF expression. This cell line originated from a murine Dexter type culture and exhibits a preadipocytic phenotype. As in human LTBMC, we could demonstrate a inhibitory effect of IFN-alpha co-incubation on GM-CSF activity in serum-free supernatants of +/+(-1).LDA11 stromal cell cultures stimulated with IL-1 or TNF-alpha or the combi…
A Dominance Variant Under the Multi-Unidimensional Pairwise-Preference Framework: Model Formulation and Markov Chain Monte Carlo Estimation.
2018
Forced-choice questionnaires have been proposed as a way to control some response biases associated with traditional questionnaire formats (e.g., Likert-type scales). Whereas classical scoring methods have issues of ipsativity, item response theory (IRT) methods have been claimed to accurately account for the latent trait structure of these instruments. In this article, the authors propose the multi-unidimensional pairwise preference two-parameter logistic (MUPP-2PL) model, a variant within Stark, Chernyshenko, and Drasgow’s MUPP framework for items that are assumed to fit a dominance model. They also introduce a Markov Chain Monte Carlo (MCMC) procedure for estimating the model’s paramete…
Qualitative and Quantitative Study on Videotaped Data for Fire Emergency Response
2016
During search and rescue (SAR) operations, information plays a significant role in empowering the emergency response personnel at various levels. But, understanding the information which is being shared between/among emergency personnel is necessary to improve current coordination systems. However, such systems can help the first responders to gain/increase their situational awareness and coordination. Moreover, there is still the lack of automatic and intelligent tools that can contribute to structure, categorize, and visualize the communicated content that occur during SAR operations. Therefore, in this paper, we present the concept of such analysis by using the qualitative methodology an…
The relationship between interdisciplinarity and distinct modes of university-industry interaction
2019
Abstract Interdisciplinary research (IDR) has raised increasing expectations among scholars and policymakers about its potential to produce ground-breaking scientific contributions and satisfy societal demands. While existing research highlights that novel connections across fields is beneficial for scientific contributions with high academic impact, comparatively less is known about whether IDR is positively associated to scientists’ engagement with non-academic actors. To investigate this, we examine whether there is a systematic relationship between scientists’ IDR-orientation and their interactions with industry. We conceptually distinguish four stylized modes of interaction (firm creat…
Changes in the cerebrovascular effects of endothelin-1 and nicardipine after experimental subarachnoid hemorrhage.
1993
The role of endothelium-related factors in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH) has gained interest since the discovery of endothelin-1 (ET-1). We have examined, before and after SAH, the responsiveness of the cerebrovascular bed of the goat to ET-1, the sources of Ca2+ in ET-1-induced responses, and the ability of the Ca2+ entry blocker nicardipine to counteract them. Before SAH, injection of ET-1 into the cerebral circulation increased cerebrovascular resistance, thereby producing dose-dependent reductions in cerebral blood flow (CBF), which were prevented by nicardipine. In isolated middle cerebral arteries, ET-1 induced concentration-dependent contr…
Subjective responses to different light sources. A study on light preferences and comparison of standard light measures with human individual estimat…
2013
The experimental research here described investigates how people perceive different light sources that have same CCTs and illuminance values on a visual task. The results show that photometric quantities like illuminances and CCTs fail to guarantee users comfort, because parameters like SPD of the light source and its technology heavily influence people's perception of an environment.