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"Critical transition"
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Socially-just radical alternatives for education and youth work practice : re-imagining ways of working with young people
\"Challenging dominant neoliberal discourses about ways of working with 'disconnected' young people, this book sets out ideas for generating radically different ways of thinking about such practices. Drawing on contemporary and historical material, the book argues that alternative approaches to formal and informal education are necessary to challenge repressive practices, and to help build a more equal, socially-just society. The book achieves this by re-imagining - with the aid of utopian studies - how formal and informal ways of working with young people might be made more empowering. Each chapter contributes to addressing the heterogeneity of experience of diverse life-worlds - in contrast to the homogenous one-size fits all approach to education and youth work that has become the dominant mode in neoliberal societies. Whilst many young people do make successful transitions to adulthood, a substantial minority are failed by an increasingly marketized social system - particularly education where young people are expected to achieve specified outcomes in a structure that does not speak to them, and leaves them wondering on the irrelevance of academic qualifications that seem to be out of their reach\"-- Provided by publisher.
Book
Resilience indicators
In the vicinity of tipping points—or more precisely bifurcation points—ecosystems recover slowly from small perturbations. Such slowness may be interpreted as a sign of low resilience in the sense that the ecosystem could easily be tipped through a critical transition into a contrasting state. Indicators of this phenomenon of 'critical slowing down (CSD)' include a rise in temporal correlation and variance. Such indicators of CSD can provide an early warning signal of a nearby tipping point. Or, they may offer a possibility to rank reefs, lakes or other ecosystems according to their resilience. The fact that CSD may happen across a wide range of complex ecosystems close to tipping points implies a powerful generality. However, indicators of CSD are not manifested in all cases where regime shifts occur. This is because not all regime shifts are associated with tipping points. Here, we review the exploding literature about this issue to provide guidance on what to expect and what not to expect when it comes to the CSD-based early warning signals for critical transitions.
Journal Article
Self-Organization of Genome Expression from Embryo to Terminal Cell Fate: Single-Cell Statistical Mechanics of Biological Regulation
A statistical mechanical mean-field approach to the temporal development of biological regulation provides a phenomenological, but basic description of the dynamical behavior of genome expression in terms of autonomous self-organization with a critical transition (Self-Organized Criticality: SOC). This approach reveals the basis of self-regulation/organization of genome expression, where the extreme complexity of living matter precludes any strict mechanistic approach. The self-organization in SOC involves two critical behaviors: scaling-divergent behavior (genome avalanche) and sandpile-type critical behavior. Genome avalanche patterns—competition between order (scaling) and disorder (divergence) reflect the opposite sequence of events characterizing the self-organization process in embryo development and helper T17 terminal cell differentiation, respectively. On the other hand, the temporal development of sandpile-type criticality (the degree of SOC control) in mouse embryo suggests the existence of an SOC control landscape with a critical transition state (i.e., the erasure of zygote-state criticality). This indicates that a phase transition of the mouse genome before and after reprogramming (immediately after the late 2-cell state) occurs through a dynamical change in a control parameter. This result provides a quantitative open-thermodynamic appreciation of the still largely qualitative notion of the epigenetic landscape. Our results suggest: (i) the existence of coherent waves of condensation/de-condensation in chromatin, which are transmitted across regions of different gene-expression levels along the genome; and (ii) essentially the same critical dynamics we observed for cell-differentiation processes exist in overall RNA expression during embryo development, which is particularly relevant because it gives further proof of SOC control of overall expression as a universal feature.
Journal Article
The Regime Shifts Database: a framework for analyzing regime shifts in social-ecological systems
Regime shifts, i.e., large, persistent, and usually unexpected changes in ecosystems and social-ecological systems, can have major impacts on ecosystem services, and consequently, on human well-being. However, the vulnerability of different regions to various regime shifts is largely unknown because evidence for the existence of regime shifts in different ecosystems and parts of the world is scattered and highly uneven. Furthermore, research tends to focus on individual regime shifts rather than comparisons across regime shifts, limiting the potential for identifying common drivers that could reduce the risk of multiple regime shifts simultaneously. Here, we introduce the Regime Shifts Database, an open-access database that systematically synthesizes information on social-ecological regime shifts across a wide range of systems using a consistent, comparative framework, providing a wide-ranging information resource for environmental planning, assessment, research, and teaching initiatives. The database currently contains 28 generic types of regime shifts and > 300 specific case studies. Each entry provides a literature-based synthesis of the key drivers and feedbacks underlying the regime shift, as well as impacts on ecosystem services and human well-being, and possible management options. Across the 28 regime shifts, climate change and agriculture-related activities are the most prominent among a wide range of drivers. Biodiversity, fisheries, and aquatic ecosystems are particularly widely affected, as are key aspects of human well-being, including livelihoods, food and nutrition, and an array of cultural ecosystem services. We hope that the database will stimulate further research and teaching on regime shifts that can inform policy and practice and ultimately enhance our collective ability to manage and govern large, abrupt, systemic changes in the Anthropocene.
Journal Article
Generic Indicators of Ecological Resilience: Inferring the Chance of a Critical Transition
Ecological resilience is the ability of a system to persist in the face of perturbations. Although resilience has been a highly influential concept, its interpretation has remained largely qualitative. Here we describe an emerging family of methods for quantifying resilience on the basis of observations. A first set of methods is based on the phenomenon of critical slowing down, which implies that recovery upon small perturbations becomes slower as a system approaches a tipping point. Such slowing down can be measured experimentally but may also be indirectly inferred from changes in natural fluctuations and spatial patterns. A second group of methods aims to characterize the resilience of alternative states in probabilistic terms based on large numbers of observations as in long time series or satellite images. These generic approaches to measuring resilience complement the system-specific knowledge needed to infer the effects of environmental change on the resilience of complex systems.
Journal Article
Planetary boundaries: Guiding human development on a changing planet
The planetary boundary (PB) concept, introduced in 2009, aimed to define the environmental limits within which humanity can safely operate. This approach has proved influential in global sustainability policy development. Steffen
et al.
provide an updated and extended analysis of the PB framework. Of the original nine proposed boundaries, they identify three (including climate change) that might push the Earth system into a new state if crossed and that also have a pervasive influence on the remaining boundaries. They also develop the PB framework so that it can be applied usefully in a regional context.
Science
, this issue
10.1126/science.1259855
Developments in the planetary boundaries concept provide a framework to support global sustainability.
The planetary boundaries framework defines a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth system. Here, we revise and update the planetary boundary framework, with a focus on the underpinning biophysical science, based on targeted input from expert research communities and on more general scientific advances over the past 5 years. Several of the boundaries now have a two-tier approach, reflecting the importance of cross-scale interactions and the regional-level heterogeneity of the processes that underpin the boundaries. Two core boundaries—climate change and biosphere integrity—have been identified, each of which has the potential on its own to drive the Earth system into a new state should they be substantially and persistently transgressed.
Journal Article
Spatial vegetation pattern formation and transition of an extended water–plant model with nonlocal or local grazing
In this paper, we analyze how vegetation patterns occur in arid and semi-arid ecosystems with different types of grazing, using both modelling approaches and mathematical analysis. The concepts of Tipping point and Turing point are helpful for us to understand the desertification that catastrophic and critical transitions may have on ecosystems. In the mathematical analysis, we extrapolated our analysis to local stability and Turing instability of local and nonlocal models. We found that the uniform vegetation state changes to vegetation pattern state or bare soil state, which means that there is overgrazing in this ecosystem. Therefore, we propose that vegetation patterns may be a warning signal for the onset of desertification. Some notes on numerical simulation are given, based on different diffusion coefficients, infiltration parameters and grazing rate. Numerical simulation not only verifies the validity of the theoretical results, but also obtains some results which can not be obtained in mathematical analysis.
Journal Article
Critical slowing down as early warning for the onset of collapse in mutualistic communities
Tipping points are crossed when small changes in external conditions cause abrupt unexpected responses in the current state of a system. In the case of ecological communities under stress, the risk of approaching a tipping point is unknown, but its stakes are high. Here, we test recently developed critical slowing-down indicators as early-warning signals for detecting the proximity to a potential tipping point in structurally complex ecological communities. We use the structure of 79 empirical mutualistic networks to simulate a scenario of gradual environmental change that leads to an abrupt first extinction event followed by a sequence of species losses until the point of complete community collapse. We find that critical slowing-down indicators derived from time series of biomasses measured at the species and community level signal the proximity to the onset of community collapse. In particular, we identify specialist species as likely the best-indicator species for monitoring the proximity of a community to collapse. In addition, trends in slowing-down indicators are strongly correlated to the timing of species extinctions. This correlation offers a promising way for mapping species resilience and ranking species risk to extinction in a given community. Our findings pave the road for combining theory on tipping points with patterns of network structure that might prove useful for the management of a broad class of ecological networks under global environmental change.
Significance Little is known on whether structurally diverse ecological networks may respond abruptly to anthropogenic stress and even less on our ability to detect such responses in advance. By simulating mutualistic communities en route to a tipping point, we show how critical slowing-down indicators may be used as early warnings for the collapse of ecological networks. Our findings not only confirm the existence of the generic dynamical signatures of tipping points in ecological networks but also suggest a promising way for identifying most vulnerable components in a broad class of networks at the brink of collapse.
Journal Article
Effects of temporal correlations in social multiplex networks
Multi-layered networks represent a major advance in the description of natural complex systems, and their study has shed light on new physical phenomena. Despite its importance, however, the role of the temporal dimension in their structure and function has not been investigated in much detail so far. Here we study the temporal correlations between layers exhibited by real social multiplex networks. At a basic level, the presence of such correlations implies a certain degree of predictability in the contact pattern, as we quantify by an extension of the entropy and mutual information analyses proposed for the single-layer case. At a different level, we demonstrate that temporal correlations are a signature of a ‘multitasking’ behavior of network agents, characterized by a higher level of switching between different social activities than expected in a uncorrelated pattern. Moreover, temporal correlations significantly affect the dynamics of coupled epidemic processes unfolding on the network. Our work opens the way for the systematic study of temporal multiplex networks and we anticipate it will be of interest to researchers in a broad array of fields.
Journal Article
Allowing variance may enlarge the safe operating space for exploited ecosystems
Variable flows of food, water, or other ecosystem services complicate planning. Management strategies that decrease variability and increase predictability may therefore be preferred. However, actions to decrease variance over short timescales (2–4 y), when applied continuously, may lead to long-term ecosystem changes with adverse consequences. We investigated the effects of managing short-term variance in three well-understood models of ecosystem services: lake eutrophication, harvest of a wild population, and yield of domestic herbivores on a rangeland. In all cases, actions to decrease variance can increase the risk of crossing critical ecosystem thresholds, resulting in less desirable ecosystem states. Managing to decrease short-term variance creates ecosystem fragility by changing the boundaries of safe operating spaces, suppressing information needed for adaptive management, cancelling signals of declining resilience, and removing pressures that may build tolerance of stress. Thus, the management of variance interacts strongly and inseparably with the management of resilience. By allowing for variation, learning, and flexibility while observing change, managers can detect opportunities and problems as they develop while sustaining the capacity to deal with them.
Journal Article