Infinities of stable periodic orbits in systems of coupled oscillators

We consider the dynamical behavior of coupled oscillators with robust heteroclinic cycles between saddles that may be periodic or chaotic. We differentiate attracting cycles into types that we call phase resetting and free running depending on whether the cycle approaches a given saddle along one or many trajectories. At loss of stability of attracting cycling, we show in a phase-resetting example the existence of an infinite family of stable periodic orbits that accumulate on the cycling, whereas for a free-running example loss of stability of the cycling gives rise to a single quasiperiodic or chaotic attractor

Multilevel governance challenges in transitioning towards a national approach for REDD+:Evidence from 23 subnational REDD+ initiatives

Although REDD+ was conceived as a national approach to reducing emissions from deforestation and forest degradation, many of the early advances have been at the subnational level. It is critical to link these subnational efforts to emerging national REDD+ frameworks, including with respect to finance and benefit distribution, setting reference levels, measurement, reporting and verification (MRV), land policy and safeguards. We use evidence from interviews with proponents from 23 subnational REDD+ initiatives in six countries to characterize the multilevel governance challenges for REDD+. We analyse the differences in perceived challenges between subnational jurisdictional programs and project-based initiatives, and then analyse proponents’ perceptions of the relationship between government policies at multiple levels and these REDD+ initiatives. We find important multilevel governance challenges related to vertical coordination and information sharing and horizontal and inter-sectoral tensions, as well as concerns over accountability, equity and justice. Though the shift to a nested, jurisdictional or national REDD+ is sometimes approached as a technical design issue, this must be accompanied by an understanding of the interests and power relations among actors at different levels. We outline challenges and suggest priority areas for future research and policy, as countries move towards a national REDD+ system

Spatial patterns of desynchronization bursts in networks

We adapt a previous model and analysis method (the {\it master stability function}), extensively used for studying the stability of the synchronous state of networks of identical chaotic oscillators, to the case of oscillators that are similar but not exactly identical. We find that bubbling induced desynchronization bursts occur for some parameter values. These bursts have spatial patterns, which can be predicted from the network connectivity matrix and the unstable periodic orbits embedded in the attractor. We test the analysis of bursts by comparison with numerical experiments. In the case that no bursting occurs, we discuss the deviations from the exactly synchronous state caused by the mismatch between oscillators

Investigating the Efficacy of Attention Bias Modification in Reducing High Spider Fear: The Role of Individual Differences in Initial Bias

Background and objectives: Attention Bias Modification (ABM) targets attention bias (AB) towards threat and is a potential therapeutic intervention for anxiety. The current study investigated whether initial AB (towards or away from spider images) influenced the effectiveness of ABM in spider fear. Methods: AB was assessed with an attentional probe task consisting of spider and neutral images presented simultaneously followed by a probe in spider congruent or spider incongruent locations. Response time (RT) differences between spider and neutral trials > 25 ms was considered 'Bias Toward' threat. RT difference < - 25 ms was considered 'Bias Away' from threat, and a difference between 25 ms and +25 ms was considered 'No Bias'. Participants were categorized into Initial Bias groups using preABM AB scores calculated at the end of the study. 66 participants' (Bias Toward n = 27, Bias Away n = 18, No Bias n = 21) were randomly assigned to ABM-active training designed to reduce or eliminate a bias toward threat and 61 (Bias Toward n = 17, Bias Away n = 18, No Bias n = 26) to ABM-controL Results: ABM-active had the largest impact on those demonstrating an initial Bias Towards spider images in terms of changing AB and reducing Spider Fear Vulnerability, with the Bias Away group experiencing least benefit from ABM. However, all Initial Bias groups benefited equally from active ABM in a Stress Task. Limitations: Participants were high spider fearful but not formally diagnosed with a specific phobia. Therefore, results should be confirmed within a clinical population. Conclusions: Individual differences in Initial Bias may be an important determinant of ABM efficacy

Performance Metrics for the Objective Assessment of Capacitive Deionization Systems

In the growing field of capacitive deionization (CDI), a number of performance metrics have emerged to describe the desalination process. Unfortunately, the separation conditions under which these metrics are measured are often not specified, resulting in optimal performance at minimal removal. Here we outline a system of performance metrics and reporting conditions that resolves this issue. Our proposed system is based on volumetric energy consumption (Wh/m$^3$) and throughput productivity (L/h/m$^2$) reported for a specific average concentration reduction, water recovery, and feed salinity. To facilitate and rationalize comparisons between devices, materials, and operation modes, we propose a nominal standard testing condition of removing 5 mM from a 20 mM NaCl feed solution at 50% water recovery for CDI research. Using this separation, we compare the desalination performance of a flow-through electrode (fte-CDI) cell and a flow between membrane (fb-MCDI) device, showing how significantly different systems can be compared in terms of generally desirable desalination characteristics. In general, we find that performance analysis must be considered carefully so to not allow for ambiguous separation conditions or the maximization of one metric at the expense of another. Additionally, for context we discuss a number of important underlying performance indicators and cell characteristics that are not performance measures in and of themselves but can be examined to better understand differences in performance

Autologous Gingival Fibroblast Culture on Commercially Available Collagen Membrane

BACKGROUND: Gingival fibroblasts play an important role in soft tissue healing and regeneration. Gingival tissue is a source for mesenchymal stem cells in tissue engineering. AIM OF THE STUDY: To assess the viability of gingival fibroblast before and after seeding on to collagen membrane. MATERIALS AND METHOD: Isolation of gingival fibroblasts was done for 5 samples. Morphology and growth characteristics was observed using a phase contrast microscope and viability was assessed using trypan blue and MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay. RESULTS: Five successful cultures yielded sufficient cells for characterization. Among five, growth characteristics and morphology were assessed for one sample. The population doubling time (PDT) and the seeding efficiency was 2.608 and 72.6% respectively. The gingival fibroblasts showed 94% viability before seeding on to collagen membrane. The MTT assay which was done after seeding on to collagen membrane suggested no considerable difference in the viability of fibroblasts. At One hour the gingival fibroblast adhered to the collagen membrane showed a rounded morphology. After 24 hours the gingival fibroblast attached to the collagen membrane showed a spindle shaped morphology. CONCLUSION: The gingival fibroblasts were isolated from gingival connective tissue of five different samples. The growth characteristics and phenotype of gingival fibroblasts was assessed for one sample. The gingival fibroblasts were assessed before and after seeding on to collagen membrane and were found to be viable