Heinz von Foerster’s research while affiliated with University of Illinois, Urbana-Champaign and other places

... Take the example of stress: A social situation perceived as stressful elicits a response of the body's hypothalamus-pituitary-adrenal axis increasing the level of glucocorticosteroids in circulation, most importantly cortisol. This could be considered a 'trivial' response (von Foerster, 1962): stress input leads to hormone output -the same input always produces the same output according to a fixed and stable dose-response relationship. If bodies were trivial machines in von Foerster's sense, the stress axis would be a universal mechanism that responds in trivial, that is, stable and predictable, ways to changes in local environments. ...

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Situating local biologies: Anthropological perspectives on environment/human entanglements

... • bionics (i.e., the application of biological methods and systems found in nature to the study and design of engineering systems), • bio-inspired computing (i.e., analyzing, formalizing, and implementing biological processes using computers), and • self-organizing systems. See [7]. ...

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A Cybernetics Perspective on Data Science: Macro and Micro Views

... By contrast, the present model focuses on overall excitability of the network as a function of spatial heterogeneity of the functional properties of the gap junctions, rather than on the propagation of activity wavefronts and the spatial patterning of such fronts; these aspects have been considered elsewhere [4,32,47,48] . Whereas we considered the global activation threshold in an electrotonically coupled smooth muscle syncytium, a general argument regarding the all-or-none character of synaptically coupled networks, such as the central nervous system, was advanced by Ashby et al. [49]. This work has not considered heteromeric gap-junction channels with both Cx45 and Cx43 proteins. ...

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Alterations in gap junction connexin43/connexin45 ratio mediate a transition from quiescence to excitation in a mathematical model of the myometrium

... Due to the aforementioned features, microwave photonics attracted considerable interest from the radar and optical societies since the 1960s [4,[177][178][179][180][181][182][183]. A number of photonics-based techniques have been developed over the past few decades, ranging from LO signal generation, waveform modulation, up-and down-conversion, distribution, beamforming, filtering, to analog-to-digital conversion, which covers almost all the RF modules in radars as shown in Fig. 5 except for antennas and amplifiers. ...

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Microwave Photonic Radars

... Modeling of bacterial growth in ecology usually makes use of the Monod equation to predict bacterial growth kinetics, and exponential decay functions are used to model bacterial decay (Wade et al., 2016). The Monod model can be improved by the use of population models, such as the von Foerster equation (M' Kendrick, 1925;von Foerster et al., 1960). By assuming the age or maturity dependence of the population (Stukalin et al., 2013;Rochman et al., 2018;Hadd and Lahbiri, 2022), one can model more complex phenomena, such as population fluctuations, which result from age-dependent decay and growth, and potentially such models could also be used to model the growth lag. ...

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Dynamic population modeling of Bacterioplankton community response to gelatinous marine zooplankton bloom collapse and its impact on marine nutrient balance

... Further continuous structure can be added, with early extensions to size and age structures proposed in Fredrickson and Tsuchiya (1963); Bell and Anderson (1967) and Sinko and Streifer (1967), for cell and animal populations, respectively. Generalisations to a p-dimensional "physiological state vector" were first made in Fredrickson et al. (1967), and we refer to Gyllenberg (1983); Webb (1985); Tucker and Zimmerman (1988); 7 Heinz von Foerster was a biophysicist with wide-ranging interests, including population growth; his "Doomsday equation" predicted that human population growth rate would become infinite (on November 13th, 2026) (Von Foerster et al., 1960). Tongue was firmly in cheek here, as the exact day coincided with what would have been his birthday. ...

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Phenotype structuring in collective cell migration:a tutorial of mathematical models and methods

... Previous studies showed that poverty, population density, literacy, distance to the road network, and residing in a rural area were associated with canine and human rabies [22,23]. For this study, we obtained several maps: a poverty raster map (approximately 1km resolution) of the proportion of people per grid square living in poverty in the FCT [20]; a literacy raster map (approximately 1km resolution) showing the proportion of men and women aged 15-49 per grid square as literate in the FCT [21]; an urban extent grid (v.1) showing the proportion of rural and urban areas in the LGA, extracted from the Global Rural-Urban Mapping Project (GRUMP v.1) [24]; and a population density map at 30 arc-second (~1 km at the equator) resolution from the World Pop project [25]. We used a 20-year average for land cover and population density. ...

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Modelling modifiable factors associated with the probability of human rabies deaths among self-reported victims of dog bites in Abuja, Nigeria

... We have now set the stage to begin with the questions posed by von Foerster et al. (1960Foerster et al. ( :1292Foerster et al. ( - 1293) concerning the productivity of elements of a population as regards the net rate of growth. ...

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The Periodic Theory of Elements for World Population

... In Ref. 110 the exponent γ = 0.99 was declared, but taking into account the realistic fitting error ± 0.03, one obtains the hyperbolic equation shown on the right side of Eq. (11). The Doomsday or hyperbolic Eq. (11) met with extraordinary interest and strong criticism because of the spectacular prediction [111][112][113][114][115][116][117][118][119][120][121] . However, starting in the 1970s and 1980s, increasing deviations from Eq. (11) were observed, fortunately showing that von Forster Doomsday would not occur. ...

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Global population: from Super-Malthus behavior to Doomsday criticality