910 research outputs found
Order-by-disorder in classical oscillator systems
We consider classical nonlinear oscillators on hexagonal lattices. When the
coupling between the elements is repulsive, we observe coexisting states, each
one with its own basin of attraction. These states differ by their degree of
synchronization and by patterns of phase-locked motion. When disorder is
introduced into the system by additive or multiplicative Gaussian noise, we
observe a non-monotonic dependence of the degree of order in the system as a
function of the noise intensity: intervals of noise intensity with low
synchronization between the oscillators alternate with intervals where more
oscillators are synchronized. In the latter case, noise induces a higher degree
of order in the sense of a larger number of nearly coinciding phases. This
order-by-disorder effect is reminiscent to the analogous phenomenon known from
spin systems. Surprisingly, this non-monotonic evolution of the degree of order
is found not only for a single interval of intermediate noise strength, but
repeatedly as a function of increasing noise intensity. We observe noise-driven
migration of oscillator phases in a rough potential landscape.Comment: 12 pages, 13 figures; comments are welcom
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Electron paramagnetic resonance investigation of the free radicals in the gas and particulate phases of cigarette smoke using spin-trapping techniques
Free radicals in cigarette smoke have been studied using spin trapping EPR techniques. 2R4F reference cigarettes were smoked using 35 ml puff volumes of 2 seconds duration, once every 60 seconds. The particulate phase of the smoke was separated from the gas phase by passing the smoke through a Cambridge filter pad. For both phases, free radicals were measured and identified. A range of spin-traps was employed: PBN, DMPO, DEPMPO, and DPPH-PBN. In the gas-phase, short-lived carbon- and oxygen- centered radicals were identified; the ratios between them changed during the smoking runs. For the first puffs, C-centered radicals predominated while for the later puffs, O-centered radicals were mainly observed. The particulate phase and the âtarâ were studied as well
Information fusion of GNSS sensor readings, field notes, and expert's a priori knowledge
Documenting machinery movements by using positioning technologies, such as global navigation satellite systems (GNSS), is essential to understand and further improve construction processes. However, before measurements can be meaningfully analysed the documented movements should be filtered to exclude outliers. Eliminating outliers manually is a time-demanding process, while automatic filtering can be inaccurate. In particular, path elements may get lost if machine-specific movements are misconceived as noisy data. As a trade-off, we propose an information fusion approach to filter paths of construction machines in a semi-automatic way. The approach allows an expert to relate âhardâ sensor and âsoftâ field records with his or her expectations about how machines can move in real construction projects. Specially developed open-source software illustrates the proposed approach for filtering the documented paths of machines involved in road paving projects. The initial testing of the developed software showed its suitability to filter outliers in GNSS data and identified possibilities for further improvements
Coupled insights from the palaeoenvironmental, historical and archaeological archives to support social-ecological resilience and the sustainable development goals
Many governments and organisations are currently aligning many aspects of their policies and practices to the sustainable development goals (SDGs). Achieving the SDGs should increase social-ecological resilience to shocks like climate change and its impacts. Here, we consider the relationship amongst the three elements�the SDGs, social-ecological resilience and climate change�as a positive feedback loop. We argue that long-term memory encoded in historical, archaeological and related �palaeo-data� is central to understanding each of these elements of the feedback loop, especially when long-term fluctuations are inherent in social-ecological systems and their responses to abrupt change. Yet, there is scant reference to the valuable contribution that can be made by these data from the past in the SDGs or their targets and indicators. The historical and archaeological records emphasise the importance of some key themes running through the SDGs including how diversity, inclusion, learning and innovation can reduce vulnerability to abrupt change, and the role of connectivity. Using paleo-data, we demonstrate how changes in the extent of water-related ecosystems as measured by indicator 6.6.1 may simply be related to natural hydroclimate variability, rather than reflecting actual progress towards Target 6.6. This highlights issues associated with using SDG indicator baselines predicated on short-term and very recent data only. Within the context of the contributions from long-term data to inform the positive feedback loop, we ask whether our current inability to substantively combat anthropogenic climate change threatens achieving both the SDGS and enhanced resilience to climate change itself. We argue that long-term records are central to understanding how and what will improve resilience and enhance our ability to both mitigate and adapt to climate change. However, for uptake of these data to occur, improved understanding of their quality and potential by policymakers and managers is required
Complement Receptor 1/Cd35 Is a Receptor for Mannan-Binding Lectin
Mannan-binding lectin (MBL), a member of the collectin family, is known to have opsonic function, although identification of its cellular receptor has been elusive. Complement C1q, which is homologous to MBL, binds to complement receptor 1 (CR1/CD35), and thus we investigated whether CR1 also functions as the MBL receptor. Radioiodinated MBL bound to recombinant soluble CR1 (sCR1) that had been immobilized on plastic with an apparent equilibrium dissociation constant of 5 nM. N-acetyl-d-glucosamine did not inhibit sCR1âMBL binding, indicating that the carbohydrate binding site of MBL is not involved in binding CR1. C1q inhibited MBL binding to immobilized sCR1, suggesting that MBL and C1q might bind to the same or adjacent sites on CR1. MBL binding to polymorphonuclear leukocytes (PMNs) was associated positively with changes in CR1 expression induced by phorbol myristate acetate. Finally, CR1 mediated the adhesion of human erythrocytes to immobilized MBL and functioned as a phagocytic receptor on PMNs for MBLâimmunoglobulin G opsonized bacteria. Thus, MBL binds to both recombinant sCR1 and cellular CR1, which supports the role of CR1 as a cellular receptor for the collectin MBL
The potential of permanent gullies in Europe as geomorphosites
Geotourism is a useful way to educate societies in the field of geomorphology and natural hazards. Geosites, including geomorphosites, represent the basis for the development of this type of tourism. This study describes twelve representative gully regions within nine European countries. The characteristics of 42 permanent gullies, gully systems and badland landscapes are presented and a geotouristic assessment of these gullies was made, based on scientific, educational, functional and touristic indicators. This assessment demonstrates a large difference between the selected gully sites, particularly with regard to functional and tourist values. The geotouristic potential of gullies is the highest in Italy and Spain and the lowest in Romania and Latvia. In some countries, permanent gullies are not regarded as geotouristic attractions at all, while in others they constitute a significant element of their tourism development strategy. Based on the analysis of scientific values of the gully sites, educational lessons to be learned were identified that are mainly related to i) gullies as a geological window, ii) present-day geomorphological processes, and iii) stages of historical gully erosion reflecting past human-environment interactions. These must be part of a broader strategy for the development of geotourism in gully regions. Gullies are potential geosites within existing or planned geoparks. Values of gullies for other forms of tourism (active, cultural, nature), should be also emphasized
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