Strong Feedback Loop Research Articles

Biases and Feedbacks in the Knowledge System: from Academia to the Public and Back

In the philosophy of science, there are multiple concepts trying to answer the question of how scientists ‘know’ things, all circling around the notion of observation, thesis, falsification and corroboration – namely, the usual concepts of scientific practice. However, a whole different question is ‘how does the public know things?’. Understanding the answer to this question is crucial, since (at least in Western democracies) the public is the entity which funds, and through funding directs to a certain extent, the course of science. Here I discuss ‘the knowledge system’, a concept (proposed by the American writer Alex Epstein), which can generally be thought of as the set of institutions and processes which take part in the way the public becomes knowledgeable about certain (scientific) topics. I argue that the ‘knowledge system’ contains two inherent flaws, namely (i) the accumulation of biases; and (ii) strong feedback loops, which are almost unavoidable. I demonstrate these flaws with some examples and show how these flaws can (and already do) lead to policy suggestions that de-facto abolish academic freedom. Finally, I discuss possible ways to overcome – or at least minimize – the effect of these flaws on science and the scientific community.

Voice, Choice and Power: Using co-production to develop a community engagement strategy for an ethnically diverse community


 
 
 The context of the COVID-19 pandemic has amplified the need to increase co-production activities to empower communities. The pandemic has further highlighted systemic health and socioeconomic inequities, especially for those from ethnic minority communities and in areas of economic deprivation. This research article presents a complex, collaborative process of co-production we undertook as part of the service design of Community Engagement work within the Better Start Bradford Programme; a program of projects for pregnant women and families with children aged 0–4 years living in an ethnically diverse area. Using theory of change as our underpinning theoretical framework, we co-produced a community engagement logic model or ‘strategy’. Our approach involved nine 90-minute workshops with a range of community stakeholders. We used the seven Scottish National Standards for Community Engagement and Communities’ self-identified key concepts of ‘voice’, ‘choice’ and ‘power’ to structure the partnership activity. Workshop discussions were analysed using qualitative framework analysis, and we developed a comprehensive, multi-faceted community engagement logic model with the community.
 Discussions with the community highlighted that (1) the COVID-19 pandemic had opened new avenues of community engagement, primarily virtual ones, and a blended offer of face-to-face and online activities; (2) vital support for community readiness to engage, facilitated through culturally sensitive engagement delivered by trusted sources, transparent governance processes and informal consultation, combined with a flexible approach to adapting to the community’s needs; (3) the need for a continuous reflective process of recruitment to key governance roles to include a range of diverse voices to ensure power is given to community voices.
 
 
 
 A strong two-way feedback loop is at the core of our community engagement strategy, with both the community and the organisation playing equal roles.
 
 
 
 
 

Perceived causal symptom network of adolescent mental health issues

Adolescent mental health is difficult to capture in categories such as depression or specific anxiety disorders. An alternative is to approach psychiatric symptoms as causal networks, potentially revealing feedback loops that maintain a pathological state. One approach to creating such networks, implemented in the PECAN methodology, is to ask adolescents about their perceptions of the causes to their symptoms. For this purpose, a transdiagnostic item list was created, and adolescents who screened positive for depression (N = 55) completed twice in two weeks a survey quantifying perceptions of causality between their mental health problems. A network that was averaged across all participants was reliable and revealed three strong feedback loops: a first loop running through stress, insomnia, fatigue, procrastination, and back to stress; a second loop between stress and overthinking; and a third loop between stress and procrastination. Although all adolescents in the study screened positive for depression, symptoms of depression were not particularly central to the network. Instead, the most central symptoms were procrastination and overthinking. The average test-retest reliability for individual networks was low, limiting clinical application. In conclusion, PECAN was found to be reliable and useful when creating a group-level network of adolescent mental health problems. While informative at a group level, the method should be improved before it can be used to inform treatment at the individual level.

Climatic legacy effects on the drought response of the Amazon rainforest.

Extreme precipitation and drought events are predicted to become more intense and more frequent over the Amazon rainforest. Because changes in forest dynamics could prompt strong feedback loops to the global climate, it is of crucial importance to gain insight into the response of tropical forests to these recurring extreme climatic events. Here, we evaluated the Amazon forest stability (resistance and resilience) to drought in the context of past dry and wet climatic events using MODIS EVI satellite imagery and cumulative water deficit anomalies. We observed large spatial differences in the occurrence of extreme climatic events from 1980 to 2019, with an increase in drought frequency in the central and northern Amazon and drought intensity in the southern Amazon basin. An increasing trend in the occurrence of wet events was found in the western, southern, and eastern Amazon. Furthermore, we found significant legacy effects of previous climatic events on the forest drought response. An extreme drought closely preceding another drought decreased forest resilience, whereas the occurrence of a recent drier-than-usual event also decreased the forest resistance to later droughts. Both wetter-than-usual and extreme wet events preceding an extreme drought increased the resistance of the forest, and with similar effects sizes as dry events, indicating that wet and dry events have similarly sized legacy effects on the drought response of tropical forests. Our results indicate that the predicted increase in drought frequency and intensity can have negative consequences for the functioning of the Amazon forest. However, more frequent wet periods in combination with these droughts could counteract their negative impact. Finally, we also found that more stable forests according to the alternative stable states theory are also more resistant and resilient to individual droughts, showing a positive relationship between the equilibrium and non-equilibrium stability dynamics.

Technology Integrated Inclusive Learning Spaces for Industry 4.0 Adaptive Learners- Lur Model for Sustainable Competency Development

Goal of learning in this millennium is to create an inclusive learning environment for all. Inclusivity in the millennial age learning environment (referred to as Learning 4.0 age) is achieved through the integration of technology and learning accessed by masses in a standardized, indiscriminate, self-paced, affordable, and technologically friendly form, while also instilling in the learners with the skills required by Industry 4.0. To fully realize Industry 4.0's potential, organizations will need to take a more creative, inclusive approach to talent development and some deliberate unlearning of outdated approaches and learning of new ones. Thus, this study focuses on the Unlearning-Relearning (LUR) model to bridge the gap between Industry-academia 4.0 and fill the skill gaps. The study highlights the need to create technology-integrated inclusive learning spaces for millennials as per the industry 4.0 requirements by proposing an 'Unlearn-Relearn Model', which incorporates advanced technology and the unlearning-relearning concept and strong feedback loop to achieve its purpose of sustainable competency development.

Human TRMT112-Methyltransferase Network Consists of Seven Partners Interacting with a Common Co-Factor.

Methylation is an essential epigenetic modification mainly catalysed by S-Adenosyl methionine-dependent methyltransferases (MTases). Several MTases require a cofactor for their metabolic stability and enzymatic activity. TRMT112 is a small evolutionary conserved protein that acts as a co-factor and activator for different MTases involved in rRNA, tRNA and protein methylation. Using a SILAC screen, we pulled down seven methyltransferases—N6AMT1, WBSCR22, METTL5, ALKBH8, THUMPD2, THUMPD3 and TRMT11—as interaction partners of TRMT112. We showed that TRMT112 stabilises all seven MTases in cells. TRMT112 and MTases exhibit a strong mutual feedback loop when expressed together in cells. TRMT112 interacts with its partners in a similar way; however, single amino acid mutations on the surface of TRMT112 reveal several differences as well. In summary, mammalian TRMT112 can be considered as a central “hub” protein that regulates the activity of at least seven methyltransferases.

Spontaneous and Perturbational Complexity in Cortical Cultures.

Dissociated cortical neurons in vitro display spontaneously synchronized, low-frequency firing patterns, which can resemble the slow wave oscillations characterizing sleep in vivo. Experiments in humans, rodents, and cortical slices have shown that awakening or the administration of activating neuromodulators decrease slow waves, while increasing the spatio-temporal complexity of responses to perturbations. In this study, we attempted to replicate those findings using in vitro cortical cultures coupled with micro-electrode arrays and chemically treated with carbachol (CCh), to modulate sleep-like activity and suppress slow oscillations. We adapted metrics such as neural complexity (NC) and the perturbational complexity index (PCI), typically employed in animal and human brain studies, to quantify complexity in simplified, unstructured networks, both during resting state and in response to electrical stimulation. After CCh administration, we found a decrease in the amplitude of the initial response and a marked enhancement of the complexity during spontaneous activity. Crucially, unlike in cortical slices and intact brains, PCI in cortical cultures displayed only a moderate increase. This dissociation suggests that PCI, a measure of the complexity of causal interactions, requires more than activating neuromodulation and that additional factors, such as an appropriate circuit architecture, may be necessary. Exploring more structured in vitro networks, characterized by the presence of strong lateral connections, recurrent excitation, and feedback loops, may thus help to identify the features that are more relevant to support causal complexity.

Scaling up of Brazil's Criança Feliz early childhood development program: an implementation science analysis.

To address inequities that prevent socioeconomically vulnerable young children from reaching their full developmental potential, Brazil implemented Programa Criança Feliz (PCF) ("Happy Child" early childhood development program) in 2934 of its 5570 municipalities. A qualitative case study was carried out on the basis of in-depth interviews with 22 key informants, employing purposive sampling, from past or current national and state coordination teams. Thematic analysis followed the RE-AIM framework, and complex adaptive system constructs mapped how barriers and enablers influenced scale-up. One overarching theme related to PCF emergence, and 18 subthemes were identified within the RE-AIM. An enabling national political environment favored PCF emergence through a top-down approach that led to governance challenges. Changes in the enrollment criteria for families facilitated reach, and evidence-based methodology favored the designing of the home visits. However, operationalizing the intersectoral actions remains a barrier for effectiveness, while intrasectoral resistance across levels delayed adoption. WhatsApp facilitated networking, capacity building, and adoption. Rushed scale-up generated barriers for quality delivery and led to different implementation pathways across municipalities. Legal institutionalization is critical to assure permanent funding and maintenance. PCF has enhanced early childhood services in Brazil, but strong negative feedback loops need to be addressed for effective sustainability.

Depression Dynamics Across a Decade: Daily Affective Experience and Yearly Depressive Symptomatology

Recent conceptualizations of depression and supporting empirical work suggests that elevations and allievations of depressive symptoms can be understood from a dynamic systems perspective. Specifically, depression is proposed to result from strong-feedback loops in a system comprised of highly interdependent component parts (e.g., affect states). Supporting this perspective, individual differences in emotional interia and strong connections across emotions at micro-level timescales have been consistently associated with individual differences in depressive symptomatology such that individuals with greater emotional inertia and cross-emotion relations show higher levels of depressive symptoms. Importantly, however, individual differences do not necessarily translate to intraindividual change. The present study explores whether emotional connectivity at the daily timescale differs within individuals across a ten-year span and how these associations relate to intraindividual changes in depressive symptomatology. The results of these individual-level analyses will help further a dynamic systems perspective of depression and help inform clinical interventions for depression.

Is Intercropping an Environmentally-Wise Alternative to Established Oil Palm Monoculture in Tropical Peatlands?

Tropical peatlands in Southeast Asia are important ecosystems that play a crucial role in global biogeochemical cycles, with a potential for strong climate feedback loops. The degradation of tropical peatlands due to the expansion of oil palm plantations and their impact on biodiversity and the carbon balance is a global concern. The majority of conversion of Southeast Asian peatlands to agriculture has been by smallholder oil palm farmers, who follow more varied cropping systems compared to industrial plantations, and have better scope for expansion of other alternative varied cropping systems if supported and encouraged. Using previously-published data on peat physicochemical properties, biodiversity and greenhouse gas emissions from small-holder oil palm plantations, we determined that prolonged oil palm monocropping for two generations would result in loss of carbon and peat functional properties that may lead to potential declassification of peatlands. We propose intercropping during the early stages of oil palm as a wise alternative for already-existing plantations in tropical peatlands to ameliorate some of the negative environmental impacts of oil palm on the physio-chemical properties of peat. However, we emphasize the need to more fully explore the sustainability of intercropping systems throughout the life cycle of palm plantations on peatlands, and integrate with current management practices. We also emphasize the further need for research to fully assess the impacts of oil palm intercropping compared to widely-practiced oil palm monocropping. Finally, we suggest changes in government certification policies to encourage intercropping practices by smallholders.

Propagation of orientation selectivity in a spiking network model of layered primary visual cortex.

Neurons in different layers of sensory cortex generally have different functional properties. But what determines firing rates and tuning properties of neurons in different layers? Orientation selectivity in primary visual cortex (V1) is an interesting case to study these questions. Thalamic projections essentially determine the preferred orientation of neurons that receive direct input. But how is this tuning propagated though layers, and how can selective responses emerge in layers that do not have direct access to the thalamus? Here we combine numerical simulations with mathematical analyses to address this problem. We find that a large-scale network, which just accounts for experimentally measured layer and cell-type specific connection probabilities, yields firing rates and orientation selectivities matching electrophysiological recordings in rodent V1 surprisingly well. Further analysis, however, is complicated by the fact that neuronal responses emerge in a dynamic fashion and cannot be directly inferred from static neuroanatomy, as some connections tend to have unintuitive effects due to recurrent interactions and strong feedback loops. These emergent phenomena can be understood by linearizing and coarse-graining. In fact, we were able to derive a low-dimensional linear dynamical system effectively describing stimulus-driven activity layer by layer. This low-dimensional system explains layer-specific firing rates and orientation tuning by accounting for the different gain factors of the aggregate system. Our theory can also be used to design novel optogenetic stimulation experiments, thus facilitating further exploration of the interplay between connectivity and function.

Iterative generation of insight from text collections through mutually reinforcing visualizations and fuzzy cognitive maps

Developing a comprehensive explanation of complex social phenomena is a difficult task that analysts often have to perform using vast collections of text documents. On the one hand, solutions exist to assist analysts in creating causal maps from text documents, but these can only articulate the relationships at work in a problem. On the other hand, Fuzzy Cognitive Maps (FCMs) can articulate these relationships and perform simulations, but no environment exists to help analysts in iteratively developing FCMs from text. In this paper, we detail the design and implementation of the first tool that allows analysts to develop FCMs from text collections, using interactive visualizations. We make three contributions: (i) we combine text mining and FCMs, (ii) we implement the first visual analytics environment built on FCMs, and (iii) we promote a strong feedback loop between interactive data exploration and model building. We provide two case studies exemplifying how to create a model from the ground-up or improve an existing one. Limitations include the increase in display complexity when working with large collection of files, and the reliance on KL-divergence for ad-hoc retrieval. Several improvements are discussed to further support analysts in creating high-quality models through interactive visualizations.

The Third, System Stage of Corporate Governance: Why Institutional Investors Need to Move Beyond Modern Portfolio Theory

This paper focuses on underlying causes for the emerging systemic emphasis among major corporate governance institutional owners. It does this by building incorporating three stages of corporate governance: structure and process as governance (stage I), broadening to include E and S factors (stage II), and stage III, a system focus. By looking at system focus this paper breaks ground by arguing one must examine the role modern portfolio theory (MPT) in the investment processes and explore how MPT impacts corporate structure, behavior and governance. We focus on the dynamics of a portfolio, and of multiple portfolios (the market) becoming part of governance analysis and actions, challenging the idea that portfolio investment risk is limited to diversifying idiosyncratic risk through security selection assuming that will have no impact on beta. There are strong feedback loops between portfolio risk management, beta and systemic risk: they are conjoined.

The Impact of Treatments for Depression on the Dynamic Network Structure of Mental States: Two Randomized Controlled Trials

Evidence is growing that vulnerability to depression may be characterized by strong negative feedback loops between mental states. It is unknown whether such dynamics between mental states can be altered by treatment. This study examined whether treatment with imipramine or treatment with Mindfulness-Based Cognitive Therapy (MBCT) reduces the connectivity within dynamic networks of mental states in individuals with depressive symptoms. In the Imipramine trial, individuals diagnosed with major depression were randomized to imipramine treatment or placebo-pill treatment (n = 50). In the Mind-Maastricht trial, individuals with residual depressive symptoms were randomized to Mindfulness-Based Cognitive Therapy (MBCT) or to a waiting-list control condition (n = 119). Lagged associations among mental states, as assessed with the Experience Sampling Method (ESM), were estimated at baseline and post-intervention. The results show that few of the dynamic network connections changed significantly over time and few of the changes after MBCT and imipramine treatment differed significantly from the control groups. The decrease in average node connectivity after MBCT did not differ from the decrease observed in the waiting-list control group. Our findings suggest that imipramine treatment and MBCT do not greatly change the dynamic network structure of mental states, even though they do reduce depressive symptomatology.

MiR-24-mediated knockdown of H2AX damages mitochondria and the insulin signaling pathway

Mitochondrial deficits or altered expressions of microRNAs are associated with the pathogenesis of various diseases, and microRNA-operated control of mitochondrial activity has been reported. Using a retrovirus-mediated short-hairpin RNA (shRNA) system, we observed that miR-24-mediated H2AX knockdown (H2AX-KD) impaired both mitochondria and the insulin signaling pathway. The overexpression of miR-24 decreased mitochondrial H2AX and disrupted mitochondrial function, as indicated by the ATP content, membrane potential and oxygen consumption. Similar mitochondrial damage was observed in shH2AX-mediated specific H2AX-KD cells. The H2AX-KD reduced the expression levels of mitochondrial transcription factor A (TFAM) and mitochondrial DNA-dependent transcripts. H2AX-KD mitochondria were swollen, and their cristae were destroyed. H2AX-KD also blocked the import of precursor proteins into mitochondria and the insulin-stimulated phosphorylation of IRS-1 (Y632) and Akt (S473 and T308). The rescue of H2AX, but not the nuclear form of ΔC24-H2AX, restored all features of miR-24- or shH2AX-mediated impairment of mitochondria. Hepatic miR-24 levels were significantly increased in db/db and ob/ob mice. A strong feedback loop may be present among miR-24, H2AX, mitochondria and the insulin signaling pathway. Our findings suggest that H2AX-targeting miR-24 may be a novel negative regulator of mitochondrial function and is implicated in the pathogenesis of insulin resistance.

Antagonistic autoregulation speeds up a homogeneous response in Escherichia coli.

By integrating positive and negative feedback loops, biological systems establish intricate gene expression patterns linked to multistability, pulsing, and oscillations. This depends on the specific characteristics of each interlinked feedback, and thus one would expect additional expression programs to be found. Here, we investigate one such program associated with an antagonistic positive and negative transcriptional autoregulatory motif derived from the multiple antibiotic resistance (mar) system of Escherichia coli. We studied the dynamics of the system by combining a predictive mathematical model with high-resolution experimental measures of the response both at the population and single-cell level. We show that in this motif the weak positive autoregulation does not slow down but rather enhances response speedup in combination with a strong negative feedback loop. This balance of feedback strengths anticipates a homogeneous population phenotype, which we corroborate experimentally. Theoretical analysis also emphasized the specific molecular properties that determine the dynamics of the mar phenotype. More broadly, response acceleration could provide a rationale for the presence of weak positive feedbacks in other biological scenarios exhibiting these interlinked regulatory architectures.

Politics as organised combat – New players and new rules of the game in Sweden

ABSTRACTIn this paper, Sweden is used as an example of how organised politics has changed quite dramatically in the last couple of decades. The paper argues that there are a number of points that has recently changed Swedish organised politics in rather fundamental ways. These changes entail a new actor constellation in Swedish politics and policy-making, decreased visibility of political processes and the emergence of a strong feedback loop between inequality, participation and public policies. What this amounts to is a very different form of elite-driven policy-making than the old corporatist structures. An amorphous and quite invisible but still highly elite-driven process has emerged, in which inequality has increased dramatically, and the impact of money on politics has become stronger even in Sweden.

Financial sector and output dynamics in the euro area: Non-linearities reconsidered

We analyze the feedback mechanisms between economic downturns and financial stress for several euro area countries. Our study employs newly constructed financial condition indices that incorporate banking variables extensively. We apply a non-linear Logistic Vector Smooth Transition Autoregressive (LVSTAR) model for investigating instabilities in the link between the financial sector and economic activity. The LVSTAR model allows for non-linear dynamics and regime changes between low and high stress regimes. It can also replicate the regime-specific amplification effects shown by our theoretical model. The amplification effects, however, change over time. Specifically after the Lehman collapse, we observe the presence of strong non-linearities and amplification mechanisms for some euro area countries. Thus, these strong amplification effects appear to be related to rare but large events, and to a low-frequency financial cycle. Prior to the financial crisis outbreak we find corridor stability even if the financial sector shock takes place in a high stress regime. More important seems to be the shock propagation over time in the economy. Only with the occurrence of rare but large events we find strong endogenous feedback loops and a loss of stability as described by the high stress regime of our theoretical model. The economy leaves the corridor of stability and is prone to adverse feedback loops.

Atmospheric responses to idealized urban land surface forcing in eastern China during the boreal spring

AbstractIn contrast to the impacts of anthropogenic aerosols and greenhouse gases, little is known about the impact of urban land surface forcing (ULSF) on large‐scale atmospheric circulation. This study explores atmospheric responses to idealized ULSF in eastern China during the boreal spring using the Community Atmosphere Model version 5.1 coupled with the Community Land Model version 4. Results show that the ULSF leads to an increased air temperature in northern China both near the surface and in the lower troposphere. Related to a strong thermal feedback loop, a middle‐upper tropospheric cooling is found in eastern China while a relatively strong warming occurs in the middle‐high latitudes, which acts to enhance the meridional temperature gradient to the north of the source region and then shifts the East Asian subtropical jet stream (EASJ) southward. A weakened southwesterly in the lower troposphere in southern China slows down moisture transportation to northern China, and the southward shifted EASJ induces strong anomalous sinking motion to the north of the Yangtze River Valley (YRV). The associated changes in moisture and vertical airflow result in moisture divergence along the YRV and convergence in southern China. Thus, the spring rain belt is shifted southward, as characterized by below‐normal rainfall extending from the Huai River Valley to South Korea and above‐normal rainfall from southern China to the south coast of Japan. In addition, analysis of the upper tropospheric wave activity signifies that large‐scale atmospheric responses due to the ULSF also exert an important influence on local climate.

Feedback between Population and Evolutionary Dynamics Determines the Fate of Social Microbial Populations

Author SummaryThe fact that rapid evolution within a species can cause dramatic ecological changes has only recently begun to be appreciated. In particular, it has often been assumed that population dynamics, controlled by ecological circumstances such as the presence of predators or disease, occur at such different timescales compared with evolutionary dynamics that they are effectively de-coupled. Recent studies, however, have found that evolution can occur over ecological timescales and thus may have important effects on ecological dynamics. Here, we demonstrate the presence of a tight coupling between population dynamics and the evolutionary dynamics of a “social” microbial gene, which allows a laboratory population of budding yeast to cooperatively break down sucrose and grow on the simpler sugars released from it. In such cooperative populations, evolution may favor non-cooperative, or “cheater” individuals that do not contribute to the public good (in this case, the products of sucrose break down), but still use that public good to grow at the expense of the individuals that do cooperate. Our study shows that a population of cooperators that is invaded by cheaters does not collapse as a result of cheater proliferation but can evolve to a viable equilibrium. However, the coexisting population is less resilient to perturbations.