Stable Regime Research Articles

Digital authoritarianism and the devolution of authoritarian rule: examining Syria’s patriotic hackers

ABSTRACT Given the sensitive nature of cybersecurity in authoritarian regimes, the existence of semi-autonomous patriotic hackers raises questions about their function because no security-adjacent actor can survive without at least tacit regime approval. Reflecting the attention that the phenomenon has received from scholars of defence and cybersecurity, the hackers’ presence has to date been viewed as a pragmatic strategy that either compensates for autocrats’ own lack of technological capacity, or that deflects blowback from high-stakes cyber operations. But less is known about how the hackers’ presence relates to authoritarian stabilization and survival agendas. This prompts this article to ask: How does the devolution of cybersecurity functions to patriotic hackers influence regime stabilization and survival agendas? Observing patriotic hacking in Syria through work on authoritarian devolution, space and cybersecurity, the article argues that while there is much precedent for authoritarian power devolution, digital devolution has novel mechanisms and effects. This is because the internet enables regimes to consciously and instrumentally manipulate the process, thereby creating a sense of constantly shifting space between themselves and the hackers that facilitates new opportunities for authoritarian stabilization and survival.

Quaternary fluvial carbonate deposits of the Almonda River Valley, Central Portugal

This paper discusses the formation and preservation of a fluvial tufa system influenced by Atlantic climate based on stratigraphical, chronological (amino-acid racemization, AAR), sedimentological and stable-isotope analyses. On the southwestern Iberian Peninsula, the tufas and associated deposits of the Almonda River valley occur as isolated terraced bodies and reach 25 m thick. AAR dated most deposits to within the warm Marine Isotope Stage 5 (MIS-5). Two Holocene ages were reset within MIS-5 based on diverse criteria. Widely varied carbonate and minor allochthonous coarse detrital facies occur arranged in four simple vertical associations. The deposit geometry and facies association distribution correspond to a low- to moderate-sloped fluvial valley consisting of several short knickpoints and extensive flat areas between them. The latter are occupied by slow-flowing water facies (carbonate sand, lime mud, phytoclast and oncoid rudstones, and up-growing stem boundstones). Facies that formed in moderate- to high-slope substrates were stromatolite, moss and down-growing stem boundstones. The homogeneous Miocene bedrock lithology and gentle structural deformation propitiated this depositional architecture. Calcite δ13C and δ18O values suggest that the aquifer water provided the outflowing Almonda water with (1) 18O-enriched water, compared with present precipitation and groundwater δ18O values, and (2) 13C-depleted CO2 from bituminous rocks and vegetation cover in the catchment. The proximity to the Atlantic coast favoured the Mesozoic-rock aquifer recharge with 18O-enriched water precipitation, assuring water availability during the formation of the studied tufas. No evidence of frequent intense erosion phases might indicate stable precipitation regimes, which would have allowed the preservation of loose fine-grained and palustrine deposits.

State history and political instability: The disadvantage of early state development

AbstractThis article hypothesizes and empirically establishes that statehood experience, accumulated over a period of up to six millennia, lies at the deep roots of the spatial distribution of political instability across non‐European countries. Using the state history index measured between 3,500 BCE and 2000 CE, I consistently obtain precise estimates that long‐standing states outside Europe, relative to their newly established counterparts, are characterized by greater political uncertainty. I postulate that a very long duration of state experience impeded the transplantation of inclusive political institutions by European colonizers, which would eventually become central to shaping countries' ability to establish politically stable regimes outside Europe. The core findings place emphasis on the long‐term legacy of early state development for contemporary political instability.

Emergence and Stability of Hierarchical Structures under Cylindrical Confinement

AbstractFocusing on the formation of hierarchical structure under cylindrical confinement, the self‐assembly of A(BC)2B multiblock copolymer of chain length N in a nanopore with size R is studied using the self‐consistent field theory. The hierarchical concentric ring (HCk), hierarchical perforated cylinder (HPk), hierarchical helix (HHk), and even hierarchical disk (HDk) is obtained with different number of mid‐thin layers k via a proposed design principle. The results show that large pore size and χAB favor the hierarchical structure with more k, while χBC prefers hierarchical structure with less k, consistent with the results of hierarchical structure in bulk. By investigating the effect of the volume fraction of the tail A block (fA), the phase transition sequence, HCk → HPk → HHk → HDk is explored, which shares the same transition of multiblock copolymer in bulk with Lk → Gk → Ck → Sk. Finally, the phase diagram with respect to the fA and R is explored, where the stability regime of these hierarchical structures is well understood. The results provide a compelling panacea for the fabrication of hierarchical 3D nanostructures under confinement.

Optomechanically induced gain using a trapped interacting Bose-Einstein condensate

We investigate the realization of the phenomenon of optomechanically induced gain in a hybrid optomechanical system consisting of an interacting Bose-Einstein condensate trapped inside the optical lattice of a cavity which is generated by an external coupling laser tuned to the red sideband of the cavity. It is shown that the system behaves as an optical transistor while the cavity is exposed to a weak input optical signal which can be amplified considerably in the cavity output if the system is in the unresolved sideband regime. Interestingly, the system has the capability to switch from the resolved to unresolved sideband regime by controlling the s-wave scattering frequency of atomic collisions. We show that the system gain can be enhanced considerably by controlling the s-wave scattering frequency as well as the coupling laser intensity while the system remains in the stable regime. Based on our obtained results, the input signal can be amplified more than 100 million percent in the system output which is much larger than those already reported in the previously proposed similar schemes.

On the Numerical Stationary Distribution of Overdamped Langevin Equation in Harmonic System

Abstract Efficient numerical algorithm for stochastic differential equation has been an important object in the research of statistical physics and mathematics for a long time. In this paper we study the highly accurate numerical algorithm of the overdamped Langevin equation. In particular, our interest is the behaviour of the numerical schemes for solving the overdamped Langevin equation in the harmonic system. Three algorithms are obtained for overdamped Langevin equation, from the large friction limit of the schemes for underdamped Langevin dynamics. We derive the explicit expression of the stationary distribution of each algorithm by analysing the discrete time trajectory, for both one-dimensional and multi-dimensional cases. The accuracy of the stationary distribution of each algorithm is illustrated by comparing to the exact Boltzmann distribution. Our results demonstrate that, the “BAOA-limit” algorithm generates the exact distribution for the harmonic system in the canonical ensemble, within the stable regime of the time interval. The other algorithms do not produce the exact distribution of the harmonic system.

Stabilization of the flat Poiseuille-type flow for viscoelastic polymeric liquid

This paper presents a numerical study for the problem of the one-dimensional flow of viscoelastic liquid polymers between two parallel plates. The equations of a rheologically modified Vinogradov–Pokrovskii (mVP) model is used for the formulation of the problem. It is shown that the problem could have multiple steady-state solutions. The evaluation of non-steady solutions was performed to see if the time-dependent solutions got eventually attracted by the steady ones. Also for the case of multiple steady solutions, it was checked which one attracts the non-steady solution if any. The evaluation of time-dependent solutions was used to estimate the stability of equilibrium states. It is revealed that stable steady-state regimes of the problem exist under certain conditions, and also there could be no more than one stable regime for any given set of parameters. The calculations were performed to estimate the values of Reynolds and Weissenberg numbers corresponding to either stable or unstable steady regimes. The result indicates that instability of the steady flow could possibly occur for arbitrary low Reynolds numbers under certain balance of viscous and elastic forces.

WHY DOES A RULER TOLERATE CORRUPTION AND HOW CAN CORRUPTION POSSIBLY BE ELIMINATED?

There is a fundamental conflict of interests between the ruler and most citizens in non-democracies. When the ruler maximizes his benefit from taxation, the major constraint is that citizens might make attempts to overthrow the existing regime. The continuity and stability of regime are crucially related to the degree of support to the existing political regime by the bureaucracy. In this paper, we use a simple model to argue that, when the ruler maximizes his benefit and faces exogenous restriction on wage setting, toleration of corruption is necessary to induce the required support and effort from the bureaucracy. We then relax the exogenous restriction on wages and study the case in which the ruler may eliminate corruption by setting efficiency wage. We also explore the possibility that the ruler may use an audit device to check corruption.

Fatigue Phase‐field Modeling for Elastomeric Materials

AbstractFatigue failure prediction of elastomeric materials plays a crucial role in engineering applications, e.g., rolling tires. Experimental investigations, as a straightforward evaluation of fatigue failure, do not enable an efficient insight due to significant time consumption. Therefore, several numerical approaches are developed to model fatigue fracture or damage behavior of material components subjected to cyclic loading. Inspired by [1], the work at hand incorporates a degrading fracture toughness into a promising phase‐field method. As a smeared crack representation, the phase‐field model does not depend upon any explicit criterion for crack evolution, e.g., crack initiation and propagation. Furthermore, this work proposes a novel algorithm, which is based on a post‐processing technique, to evaluate the energy release rate for PARIS' parameters during the stable crack propagation regime. The methodology is implemented into the Finite Element framework and a demonstrative numerical example is simulated.

Hydrodynamic instability of odd-viscosity-induced shear-imposed falling film

In this paper, an analysis of linear and weakly nonlinear stability for an odd-viscosity-induced shear-imposed falling film over an inclined plane is performed. Using the Chebyshev spectral collocation approach, the linear effect for disturbance of arbitrary wavenumbers is numerically examined by solving the Orr–Sommerfeld eigenvalue problem within the framework of normal mode analysis. The study reveals that instability rises with increasing external shear in the streamwise direction. However, as external shear rises in the reverse flow direction, wave energy is dissipated, and the surface wave stabilizes. Furthermore, the longwave expansion method is applied to calculate the nonlinear surface deformation expression, and it is found that the odd viscosity has the ability to stabilize the fluid flow instability caused by a positive shear force. The investigation of weakly nonlinear stability is also performed using the multiple scale method, which led to the Ginzburg–Landau equation of the nonlinear surface deformation equation. The corresponding results confirm the significant effect of both imposed shear and odd viscosity coefficient on the existent subcritical unstable and supercritical stable zones along with unconditional and explosive zones near the threshold of the film flow instability. The bandwidth of the subcritical stable zone mitigates for the higher viscosity ratio while it enhances the flow-directed potent imposed shear. Additionally, the amplitude and phase speed of nonlinear waves in the supercritical stable regime rise with increasing induced shear in the fluid flow direction and gradually decrease with increasing the value of the odd viscosity coefficient.

Natural Convection Instabilities Using the Lattice Boltzmann Method: Cavity Aspect Ratio Effect

In this paper, the natural convection instability flows in a partial heating cavity filled with air and cooled by the top wall are numerically investigated using the lattice Boltzmann method; and the cavity is partially heated and contains a heat source from below that is presented as an electronic component. To track the cavity aspect ratio effect on the heat transfer over time, first, a series of numerical simulations is completed by varying the aspect ratio of the cavity from to . The results show that the change in aspect ratio has a noticeable impact on the heat transfer behavior, specifically on the temperature distribution in the cavity, and the numerical results obtained indicate two different temperature distribution regimes: a stable steady regime, and a stable oscillatory regime. In the second step, a numerical simulation is done to study the natural convection instability into the cavity for the aspect ratio configuration of . The results show that the cavity structure has an important effect on the heat transfer in the cavity. The lattice Boltzmann method choice as a numerical simulation approach is due to its considerable result in fluid flow simulation and also to its simplicity of implementation, and it has become a suitable alternative method for solving fluid dynamics and thermal problems, as well as challenged traditional methods in many sectors by its simplicity of implementation.

Single‐Well Pore Pressure Preconditioning for Enhanced Geothermal System Stimulation

AbstractThe stress state is an important parameter in terms of both earthquake nucleation and rupture. Here, a new stimulation technique is proposed for Enhanced Geothermal Systems (EGSs), which have previously been burdened with a number of high‐profile incidences of induced seismicity. This stimulation technique pre‐emptively alters, or preconditions, the stress state before injection. This preconditioning is achieved through fluid production, such that the zone of reduced pore pressure around the well results in a stress‐ and fracture‐energy‐ barrier to potential nucleating and/or propagating ruptures near the point of injection. Using an existing 1‐D linear slip‐weakening model, it is shown how this methodology has the potential to either suppress the nucleation of dynamic events or halt their propagation. In particular, reducing the pore pressure around the region to be stimulated such that the residual shear stress rises above the in‐situ value of shear stress results in ultimately stable nucleation regimes. These results hold for injection times which are small compared to the required time of production, but this methodology results in nucleation lengths, or, analogously, stimulated areas, which are orders of magnitudes larger than those safely achievable without preconditioning. An example of how this approach may be applied in the field as well as other possible methods to achieve a preconditioned reservoir are provided. Both laboratory‐scale and meso‐scale testing of preconditioning are recommended to further constrain the applicability of this methodology for the creation of EGSs.

Prediction of NOx Emission Based on Data of LHD On-Board Monitoring System in a Deep Underground Mine

The underground mining industry is at the forefront when it comes to unsafe conditions at workplaces. As mining depths continue to increase and the mining fronts move away from the ventilation shafts, gas hazards are increasing. In this article, the authors developed a statistical polynomial model for nitrogen oxide (NOx) emission prediction of the LHD vehicle with a diesel engine. The best-achieved prediction accuracy by the 4th order polynomial model for 11 and 10 input variables is about 8% and 13%, respectively. It is comparable with the sensors’ accuracy of 10% at a stable regime of loading and 20% in the transient periods of operation. The obtained results allow planning of ventilation system capacity and power demand for the large fleet of vehicles in the deep underground mines.

Giant Kelp Forest Resilience to Ocean Warming; Historical and Modern Systems

Giant kelp forests of the North Pacific are iconic among cool temperate marine communities. They are also amongst the most productive marine ecosystems, harboring significant biodiversity and supporting coastal economies. The fate of these systems over the next eight decades is uncertain, given the variance of outcomes for global warming scenarios and the complexities of ecological forecasting. There is a growing consensus that giant kelp will be susceptible to warming, leading to a decline of the communities. Kelp forest dynamics, however, are also controlled by biotic interactions. In the North Pacific, the main biotic factors today are kelp herbivory, especially by grazing sea urchins, and predatory control of the urchins, particularly by sea otters and sunflower sea stars. A recent study demonstrated that as late as the 18th century, the now extinct mega herbivore Steller’s sea cow, an obligate kelp browser, had a significant impact on North Pacific kelp forest dynamics. Mathematical models comparing the historical community to modern ones indicated that the sea cow would have increased forest resilience against reductions of predation of urchins caused by multiple types of perturbation. In addition to epidemics and temperature anomalies, it is expected that global temperatures will increase 2-4 degrees Celsius by the year 2100. Here we use the mathematical models to explore forest dynamics under various warming scenarios, including the changing impacts of epidemics and the frequency and intensity of warming anomalies. Preliminary results suggest that in contrast to a stable temperature regime, warming to 4 degrees increases chaotic dynamics, extinction of both sea urchins and sunflower sea stars, and abundance of understory algae. Those results also suggest that chaos and algal increase would be lessened in the presence of the extinct herbivore. These findings bear implications for future kelp forest management, conservation, and human economic exploitation.

Wildfire-induced shifts in groundwater discharge to streams identified with paired air and stream water temperature analyses

Within the western United States, increasingly severe and frequent wildfires may alter the magnitude, timing, and quality of water exported from burned areas by streams. Post-fire hydrologic studies often focus on peak stream flow responses to shifts in runoff generation or on annual streamflow yield response to changes in evapotranspiration following fire. However, the magnitude and duration of wildfire effects on groundwater recharge, changes in subsurface routing, and consequences for stream low flows sourced predominately by baseflow are poorly understood. Here, we demonstrate an approach using the amplitude and phase of paired annual air and stream water temperature signals to broadly identify changes in watershed subsurface flow contributions after fire. Watersheds were classified using pre-fire temperature data, as having air-coupled (i.e., reduced apparent groundwater signature), deep groundwater, or shallow groundwater stream temperature signals. Changes in pre- and post-fire paired air and stream water temperature metrics were compared for locations (n = 17) spanning a large range of physiographic and climatic conditions across the western United States. Pre- and post-fire comparisons were computed by quantile using bootstrapped confidence intervals (ci = 95), as well as in aggregate using Kruskal-Wallis and post-hoc Dunn tests. Statistical comparisons of pre- and post-fire temperature metrics suggest that overall, watersheds classified as having minimal groundwater influence are the most likely to experience fire-induced subsurface hydrologic change. More specifically, watersheds classified as having air-coupled or shallow groundwater signals experienced increases in the magnitude of groundwater discharge, with more stable annual thermal regimes post-fire that are less-coupled to ambient air temperature. These findings form the basis of a conceptual framework for watershed resistance to subsurface hydrologic change following fire that can be broadly applied as a first approximation for water management, impacts on aquatic habitat, and post-wildfire response planning.

Key Actors’ Perspectives on Agroforestry’s Potential in North Eastern Germany

As a land use management system, agroforestry has environmental, economic and societal benefits over conventional agriculture or forestry. Important benefits of combining tree growth with agricultural crops and/or forage production systems include higher biodiversity through more diverse habitats, the control of runoff and soil erosion, the augmentation of soil water availability, the creation of microclimates, carbon sequestration and provision of a more diverse farm economy. As the climate changes, north eastern Germany is likely to be particularly prone to severe effects from droughts and wind erosion in the future. However, the area of land under agroforestry makes up less than 2% of the total agricultural area in Germany. Through qualitative interviews with key actors, this study analyzed the benefits of, potentials for and barriers to implementing agroforestry systems in the federal state of Brandenburg. Results showed that agroforestry systems have significant potential in relation to several benefits, particularly the mitigation of soil erosion and stabilization of microclimate regimes. Additionally, agroforestry has the potential to provide wood for energy production or material uses. Although a small but highly innovative and interlinked community exists, administrative barriers and high start-up costs currently hamper the transition from conventional agriculture to agroforestry systems.

Investigating Hydroclimatic Variables Trends on the Natural Lakes of Western Greece Using Earth Observation Data.

Expected global climate change is allegedly becoming more intense, and the impacts on water resources are being tracked in various hydroclimatic regimes. The present research investigates a hydrologically important area of Greece, where four natural lakes are concentrated. It aims to quantify any potential long-term trends in lake water area, precipitation, and temperature timeseries. Water area timeseries spanning four decades are estimated by the mNDWI from Landsat satellite imagery and used as an index of each lake's water storage. Precipitation and temperature measurements are obtained from the open access datasets Hydroscope and ERA5-Land, respectively. All of the timeseries were tested seasonally and annually with the Pettitt and Mann-Kendal tests for statistically significant breakpoints and trends detection. No timeseries analysis resulted in a statistically significant (at 0.05 or 0.1 levels) annual or seasonal trend. The hydroclimatic regime over the past forty years in western Greece is found to have been relatively stable. Land use was also assessed to have been relatively unchanging, converging to the overall stability of the local water regime. However, the findings of this research should not be interpreted as a reassurance against climate change, but as a call to further research for the detailed regional and local assessment of climate change and hydroclimatic variability with acknowledged statistical approaches.

Heat and Material Balance of Heliopyrolysis Device

The article proposes a technological scheme for the process of obtaining alternative fuels from local biomass by the method of heliopyrolysis. Besides, the temperature regime in the reactor of the pyrolysis device and the thermal energy savings consumed for the specific needs of the device, as well as the thermal performance of the device are analyzed. It is known that reducing energy consumption in pyrolysis technology is a major challenge because energy (heat) must first be supplied to maintain the reactor temperature regime. Typically, the processes carried out in a pyrolysis unit are carried out at the expense of coal, natural gas or electricity consumption. For the operation very large amount of thermal energy is required to decompose biomass waste, and additional heating of biomass requires excessive energy consumption. To prevent these technological problems, the article proposes a solar concentrator’s heliopyrolysis system to heat the pyrolysis reactor. Applying a solar concentrator to this type of pyrolysis device can achieve a temperature of 400–700 °C. A schematic diagram of the experimental pyrolysis unit of the solar concentrator was developed, and samples of alternative fuels (pyrogas, liquid, solid fuels) were obtained as a result of thermal processing of biomass. Based on the analysis of the material balance of a heliopyrolysis plant with a parabolic-cylindrical solar concentrator, it was found that about 20 % pyrogas, 60 % liquid fuel, 8–20 % solid alternative fuel were obtained during the pyrolysis of cotton stalks with an initial biomass load of 3.76 kg. In order to determine the consumption of thermal energy in the pyrolysis process, as well as for the replaced solar energy, an analysis of the heat balance of the proposed installation was carried out. It is shown that the use of a solar concentrator makes it possible to reduce the specific energy consumption for the pyrolysis process by up to 30 %. The proposed heliopyrolysis device makes it possible to reduce the consumption of thermal energy for own needs, increase the overall efficiency of the installation and ensure a stable temperature regime for pyrolysis.

Employment stability and decent work: Trends, characteristics and determinants in a liberal market economy

It is often assumed that the ideological dominance of neoliberalism has profoundly altered job security and long-term employment relationships. Such claims of a more unstable and insecure jobs market in the twenty-first century are the focus of this paper. Using Labour Force Survey data employment stability in the private sector over more than 20 years in Ireland is examined. As a liberal market economy, Ireland represents a fitting context in which to examine this issue given that it is one of the world's most globalised economies and among the most severely affected by the global financial crisis. Assertions of a more unstable and insecure labour market are not in the main supported by our findings. Reasons suggested for the persistence of a stable employment regime are the continued strategic institutional role of trade unions in influencing regulation, and the interest of employers in retaining skilled employees. However, the emergence of the challenging economic conditions since the pandemic may challenge trade union capacity and employer support for such stability.

Noise-modulated multistable synapses in a Wilson-Cowan-based model of plasticity.

Frequency-dependent plasticity refers to changes in synaptic strength in response to different stimulation frequencies. Resonance is a factor known to be of importance in such frequency dependence, however, the role of neural noise in the process remains elusive. Considering the brain is an inherently noisy system, understanding its effects may prove beneficial in shaping therapeutic interventions based on non-invasive brain stimulation protocols. The Wilson-Cowan (WC) model is a well-established model to describe the average dynamics of neural populations and has been shown to exhibit bistability in the presence of noise. However, the important question of how the different stable regimes in the WC model can affect synaptic plasticity when cortical populations interact has not yet been addressed. Therefore, we investigated plasticity dynamics in a WC-based model of interacting neural populations coupled with activity-dependent synapses in which a periodic stimulation was applied in the presence of noise of controlled intensity. The results indicate that for a narrow range of the noise variance, synaptic strength can be optimized. In particular, there is a regime of noise intensity for which synaptic strength presents a triple-stable state. Regulating noise intensity affects the probability that the system chooses one of the stable states, thereby controlling plasticity. These results suggest that noise is a highly influential factor in determining the outcome of plasticity induced by stimulation.