Dynamics of arc-continent collision: the role of crustal-mantle dynamics on controlling the spatio-temporal evolution of stress 

2021 ◽  
Author(s):  
Andres Felipe Rodriguez Corcho ◽  
Sara Morón ◽  
Rebecca Farrington ◽  
Romain Beucher ◽  
Louis Moresi ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
Large Scale ◽  
Temporal Evolution ◽  
Density Contrast ◽  
Simultaneous Occurrence ◽  
Return Flow ◽  
Continental Lithosphere ◽  
Mantle Dynamics ◽  
Spatio Temporal

<p>Arc-continent collision is the process by which intra-oceanic arc crust is accreted to continental margins and the most important mechanism that enables the growth of the continental crust since Phanerozoic times. We use numerical visco-plastic mechanical models to explore: (i) the role of lithospheric-mantle dynamics in controlling the spatio-temporal evolution of stress in arc-continent collision settings, and (ii) the role of density contrasts in the evolution of the stress regime. We performed a series of simulations only varying the thickness of the arc based on natural examples as the arc thickness controls the buoyancy of intra-oceanic arcs. Therefore, we investigated a range of density contrasts between the arc and the continental plate. Modelling results show that arc-continent collision can evolve into two contrasting scenarios: (i) slab-anchoring and arc transference in dense arcs where the density contrast between the arc and the adjacent continental lithosphere is above -3% (15-31 km in thickness); and (ii) slab break-off in buoyant arcs where the density contrast between the arc and the adjacent continental lithosphere is below -3% (32-35 km in thickness). We conclude that the large-scale mantle return flow emerged from slab-anchoring facilitates the simultaneous occurrence of compression and extension in the margin by enhancing: (i) compression and lithospheric thickening of the buoyant intra-oceanic arc crust; and (ii) the density contrast between the accreted arc and the continental margin that triggers the release of a gravitational flow. In the particular case of buoyant arcs, the compressional body force applied by the deformed arc to the subducting plate drives its passive retreat. The results of our numerical modelling highlight the importance of the role of lithospheric-mantle dynamics on controlling the spatio-temporal evolution of stress.</p>

scholarly journals Contribution of low-frequency climatic–oceanic oscillations to streamflow variability in small, coastal rivers of the Sierra Nevada de Santa Marta (Colombia)

2019 ◽  
Vol 23 (5) ◽  
pp. 2379-2400 ◽  
Author(s):  
Juan Camilo Restrepo ◽  
Aldemar Higgins ◽  
Jaime Escobar ◽  
Silvio Ospino ◽  
Natalia Hoyos
Keyword(s):  
Energy Spectrum ◽  
Sierra Nevada ◽  
Large Scale ◽  
Low Frequency ◽  
Maximum Power ◽  
Simultaneous Occurrence ◽  
Atmospheric Processes ◽  
Low Frequency Oscillations ◽  
Streamflow Variability

Abstract. This study evaluated the influence of low-frequency oscillations, that are linked to large-scale oceanographic–atmospheric processes, on streamflow variability in small tropical coastal mountain rivers of the Sierra Nevada de Santa Marta, Colombia. We used data from six rivers that had > 32 years of complete, continuous monthly streamflow records. This investigation employed spectral analyses to (1) explore temporal characteristics of streamflow variability, (2) estimate the net contribution to the energy spectrum of low-frequency oscillations to streamflow anomalies, and (3) analyze the linkages between streamflow anomalies and large-scale, low-frequency oceanographic–atmospheric processes. Wavelet analyses indicate that the 8–12-year component exhibited a quasi-stationary state, with a peak of maximum power between 1985 and 2005. These oscillations were nearly in phase in all rivers. Maximum power peaks occurred for the Palomino and Rancheria rivers in 1985 and 1995, respectively. The wavelet spectrum highlights a change in river variability patterns between 1995 and 2015, characterized by a shift towards the low-frequency oscillations' domain (8–12 years). The net contribution of these oscillations to the energy spectrum was as high as 51 %, a value much larger than previously thought for rivers in northwestern South America. The simultaneous occurrence of hydrologic oscillations, as well as the increase in the amplitude of the 8–12-year band, defined periods of extremely anomalous wet seasons during 1989–1990, 1998–2002 and 2010–2011, reflecting the role of low-frequency oscillations in modulating streamflow variability in these rivers. Cross-wavelet transform and wavelet coherence revealed high common powers and significant coherences in low-frequency bands (>96 months) between streamflow anomalies and Atlantic Meridional Oscillation (AMO), Pacific Decadal Oscillation (PDO) and the Tropical North Atlantic Index (TNA). These results show the role of large-scale, low-frequency oceanographic–climate processes in modulating the long-term hydrological variability of these rivers.

scholarly journals ON SPATIAL CONSENSUS FORMATION: IS THE SZNAJD MODEL DIFFERENT FROM A VOTER MODEL?

2003 ◽  
Vol 14 (10) ◽  
pp. 1331-1354 ◽  
Author(s):  
LAXMIDHAR BEHERA ◽  
FRANK SCHWEITZER
Keyword(s):  
Computer Simulations ◽  
Nearest Neighbor ◽  
Temporal Evolution ◽  
Relaxation Times ◽  
Nearest Neighbors ◽  
Voter Model ◽  
Consensus Formation ◽  
Spatio Temporal ◽  
Update Rules

In this paper, we investigate the so-called "Sznajd Model" (SM) in one dimension, which is a simple cellular automata approach to consensus formation among two opposite opinions (described by spin up or down). To elucidate the SM dynamics, we first provide results of computer simulations for the spatio-temporal evolution of the opinion distribution L(t), the evolution of magnetization m(t), the distribution of decision times P(τ) and relaxation times P(μ). In the main part of the paper, it is shown that the SM can be completely reformulated in terms of a linear voter model (VM), where the transition rates towards a given opinion are directly proportional to frequency of the respective opinion of the second-nearest neighbors (no matter what the nearest neighbors are). So, the SM dynamics can be reduced to one rule, "Just follow your second-nearest neighbor". The equivalence is demonstrated by extensive computer simulations that show the same behavior between SM and VM in terms of L(t), m(t), P(τ), P(μ), and the final attractor statistics. The reformulation of the SM in terms of a VM involves a new parameter σ, to bias between anti- and ferromagnetic decisions in the case of frustration. We show that σ plays a crucial role in explaining the phase transition observed in SM. We further explore the role of synchronous versus asynchronous update rules on the intermediate dynamics and the final attractors. As compared to the original SM, we find three additional attractors, two of them related to an asymmetric coexistence between the opposite opinions.

scholarly journals Histological and biochemical changes in Pinus spp. seeds during germination and post-germinative growth: triacylglycerol distribution and catalase activity

2000 ◽  
Vol 27 (12) ◽  
pp. 1109
Author(s):  
Marie-Noëlle Jordy ◽  
Susanna Danti ◽  
Jean-Michel Favre ◽  
Milvia Luisa Raccchi
Keyword(s):  
Apical Meristem ◽  
Temporal Evolution ◽  
Peripheral Zone ◽  
Pinus Pinaster Ait ◽  
Storage Area ◽  
Spatio Temporal ◽  
Mother Cells ◽  
Pinus Spp ◽  
Specific Lipid

The spatio-temporal evolution of catalase (CAT) activity and triacylglycerol distribution was investigated in seeds and seedlings from Pinus pinaster Ait., P. pinea L. and P. radiata D. Don during germination and post-germination. The high amount of triacylglycerols contained in the whole dehydrated embryo from the three species was progressively depleted, first, in the radicle and then in hypocotyl and cotyledons during post-germinative growth. In parallel, histological localisation of CAT activity and the quantitative analysis confirmed the involvement of this enzyme in cell detoxification from peroxide released during the intense lipid breakdown. Two isozymes, CAT-1 and CAT-2, were identified during post-germinative growth. Both were particularly active in the hypocotyl and radicle, while CAT-2 was specifically active in the photosynthetic tissues. These results emphasise that CAT activity is also independent from lipid metabolism in certain tissues. The role of each isoenzyme is discussed in connection with the metabolic changes occurring during seed germination and seedling growth. Special attention is given to the role of the shoot apex in triacylglycerol storage and breakdown. Central mother cells have been shown as a specific lipid storage area of the shoot apical meristem, in contrast with the peripheral zone in which lipid reserves were always reduced.

scholarly journals ROLE OF THE COLORED NOISE IN SPATIO-TEMPORAL BEHAVIOR OF TWO COMPETING SPECIES

2005 ◽  
Vol 05 (02) ◽  
pp. L337-L342 ◽  
Author(s):  
D. VALENTI ◽  
A. FIASCONARO ◽  
B. SPAGNOLO
Keyword(s):  
Noise Intensity ◽  
Large Scale ◽  
Colored Noise ◽  
Spatial Distributions ◽  
Temporal Behavior ◽  
Spatial Correlations ◽  
Interacting Species ◽  
Spatio Temporal ◽  
Nonmonotonic Behavior

We study the spatial distributions of two randomly interacting species, in the presence of an external multiplicative colored noise. The dynamics of the ecosystem is described by a coupled map lattice model. We find a nonmonotonic behavior in the formation of large scale spatial correlations as a function of the multiplicative colored noise intensity. This behavior is shifted towards higher values of the noise intensity for increasing correlation time of the noise.

Spatio-temporal evolution of thin Alfven resonance layer

2010 ◽  
Vol 76 (5) ◽  
pp. 709-734
Author(s):  
I. S. DMITRIENKO
Keyword(s):  
Large Scale ◽  
Temporal Evolution ◽  
Spatial Structures ◽  
One Dimensional ◽  
Resonance Detuning ◽  
Different Types ◽  
Temporal Structures ◽  
Spatio Temporal ◽  
Over Time ◽  
Resonance Equation

AbstractWe describe the spatio-temporal evolution of one-dimensional Alfven resonance disturbance in the presence of various factors of resonance detuning: dispersion and absorption of Alfven disturbance, nonstationarity of large-scale wave generating resonant disturbance. Using analytical solutions to the resonance equation, we determine conditions for forming qualitatively different spatial and temporal structures of resonant Alfven disturbances. We also present analytical descriptions of quasi-stationary and non-stationary spatial structures formed in the resonant layer, and their evolution over time for cases of drivers of different types corresponding to large-scale waves localized in the direction of inhomogeneity and to nonlocalized large-scale waves.

scholarly journals Why a Large-Scale Mode Can Be Essential for Understanding Intracellular Actin Waves

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1533 ◽  
Author(s):  
Carsten Beta ◽  
Nir S. Gov ◽  
Arik Yochelis
Keyword(s):  
Large Scale ◽  
Mass Conservation ◽  
Coarse Grained ◽  
Cellular Functions ◽  
Multi Scale ◽  
Spatio Temporal ◽  
Actin Waves ◽  
Inhibitor Type ◽  
Activator Inhibitor Type

During the last decade, intracellular actin waves have attracted much attention due to their essential role in various cellular functions, ranging from motility to cytokinesis. Experimental methods have advanced significantly and can capture the dynamics of actin waves over a large range of spatio-temporal scales. However, the corresponding coarse-grained theory mostly avoids the full complexity of this multi-scale phenomenon. In this perspective, we focus on a minimal continuum model of activator–inhibitor type and highlight the qualitative role of mass conservation, which is typically overlooked. Specifically, our interest is to connect between the mathematical mechanisms of pattern formation in the presence of a large-scale mode, due to mass conservation, and distinct behaviors of actin waves.

Non-Linear Mechanisms in the Brain

1998 ◽  
Vol 53 (7-8) ◽  
pp. 677-685 ◽  
Author(s):  
Gottfried Mayer-Kress
Keyword(s):  
Large Scale ◽  
Brain Activity ◽  
External Noise ◽  
Neuronal System ◽  
Neuron Models ◽  
General Role ◽  
Non Linear ◽  
Spatio Temporal ◽  
The Brain

Abstract Non-linear dynamical models of brain activity can describe the spontaneous emergence of large-scale coherent structures both in a temporal and spatial domain. We discuss a number of discrete time dynamical neuron models that illustrate some of the mechanisms involved. Of special interest is the phenomenon of spatio-temporal stochastic resonance in which co­herent structures emerge as a result of the interaction of the neuronal system with external noise at a given level punitive data. We then discuss the general role of stochastic noise in brain dynamics and how similar concepts can be studied in the context of networks of con­nected brains on the Internet.

scholarly journals Analysis of Forest Deforestation and its Driving Factors in Myanmar from 1988 to 2017

2019 ◽  
Vol 11 (11) ◽  
pp. 3047 ◽  
Author(s):  
Rongfeng Yang ◽  
Yi Luo ◽  
Kun Yang ◽  
Liang Hong ◽  
Xiaolu Zhou
Keyword(s):  
Land Cover ◽  
Large Scale ◽  
Forest Cover ◽  
Agricultural Land ◽  
Temporal Evolution ◽  
Driving Factors ◽  
Deforestation Rate ◽  
Land Cover Data ◽  
Spatio Temporal ◽  
Landsat Satellite

Myanmar, abundant in natural resources, is one of the countries with high forest cover in Southeast Asia. Along with its rapid socio-economic development, however, the construction of large-scale infrastructure, expansion of agricultural land, and an increasing demand for timber products have posed serious threats to the forests and significantly affected regional sustainable development. However, the geographical environment in Myanmar is complex, resulting in the lack of long-term sequence of land cover data products. Based on 30 years’ Landsat satellite remote sensing imagery data and the land cover data extracted by a mixed classification method, this paper examined the spatial and temporal evolution characteristics of forest cover in Myanmar and investigated driving factors of the spatio-temporal evolution. Results show that the forest cover has decreased by 110,621 km2 in the past 30 years with the annual deforestation rate of 0.87%. Cropland expansion is the main reason for the deforestation throughout the study period. The study can provide basic information of the forest cover data to the Myanmar government for ecological environment protection. At the same time, it can provide important support to the “Belt and Road” initiative to invest in the region’s economy.

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